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February 28, 2007

Project Status: 28 Feb 2007 (IOP7; Wednesday Mid-Day)

Isolated showers continue to pop up over the American River Basin, but they are shallow, small in size and short in duration. Model guidance suggests that this regime may continue for another 18 hours, but there won't be more than 0.1 to 0.2 inches of liquid in any 6 h period.

The SMART-R has been operating almost continuously (down for an hour yesterday when no echoes were within range) since last Saturday evening and with no apparent data problems. Truly, this has been a marathon effort for the SMART-R crew of Les Showell and Gordon Carrie.

Although the forecast calls for very small amounts of precipitation to fall overnight, we have decided to declare the end of IOP-7 at 00 UTC 1 March (4 pm PST). This will allow Les and Gordon to pack up the SMART-R and drive it down to Auburn prior to sunset, when the roads will become less safe. Tomorrow, Les will start to drive the SMART-R back to Norman. We wish him safe travels


Kingsmill

Project Status: 28 Feb 2007 (IOP7; Wednesday Morning)

IOP-7 continues, but we are getting close to the end. Only a few isolated showers are over the American River Basin at present and activity will likely decrease as we approach the noon hour. A final decision on when to terminate the IOP will be made during our coordination call at 1930 UTC

Status issues:

1. There was a power outage at Big Bend from 22 UTC 27 Feb through 05 UTC 28 Feb
2. There has been a disruption in data telemetry from Colfax (CFC), most likely due to snow on the satelitte communications dish.


Kingsmill

Project Status: 27 Feb 2007 (IOP7; Tuesday Evening)

Precipitation rates in the American River Basin have increased sharply and been relatively steady since about 00 UTC. This trend should continue for a few more hours after which the precipitation will likely become more showery.

Status update: Surface meteorology data at Big Bend has not been updating since 22 UTC, which probably can be attributed to a data communication (phone line) problem.

Kingsmill

February 27, 2007

Project Status: 27 Feb 2007 (IOP7; Tuesday Mid-Day)

IOP-7 continues....More precipitation echoes are starting to make their way toward the American River Basin from the west-northwest. It is expected that the areal coverage of these echoes will increase during the afternoon and evening, as will the precipitation rates. Present thinking is that the precipitation will continue overnight and into Wednesday morning, decreasing during the afternoon and evening.

Sounding operations for IOP-7 concluded this morning with the 16 UTC launches from Reno and Sloughhouse. Soundings from Reno went well, whereas there were many problems with the soundings at Sloughhouse. These problems could be related to a faulty data acquisition computer, RF interference at the site or maybe a bad batch of sondes. Diagnosis of the problem is in progress.

SMART-R operations will continue overnight into Wednesday. A decision on when to terminate SMART-R operations will be made during the coordination call on Wednesday.

Other status issues:

1. The Sloughhouse profiler is still down. An engineer will be at the site on Thursday to begin repairs
2. The Colfax profiler went down overnight (08 UTC) due to a power failure. The system came back online at about 19 UTC


Kingsmill

Project Status: 27 Feb 2007 (IOP7; Tuesday Morning)

IOP-7 continues........The most intense precipitation last night occurred early in the evening. After about 03-04 UTC, the precipitation became more showery. This morning, the showery pattern is still evident, with isolated radar echoes scattered about the American River Basin. These isolated showers are likely to persist through the day in a very unstable air mass with snow levels dropping from 2000 feet down to maybe 1000 feet. Precipitation will likely become more widespread later this afternoon into tonight with rates increasing from their present relatively meager levels.

Status issue:

The SMART-R crew of Les Showell and Gordon Carrie will be staying in a nearby trailer for the duration of the IOP so that they do not have to travel between Foresthill and Auburn on an icy road. Les and Gordon are truly "roughing it" to allow SMART-R data collection throughout the IOP and we owe them a debt of gratitude for their efforts.


Kingsmill

Project Status: 26 Feb 2007 (IOP7; Monday Evening)

Here is the much delayed project status for today (apologies to all):

IOP #7 continues to roll along offering us much to ponder. We are not expecting a well-defined FROPA, but rather a long cold-advection process which is expected to begin at about 22Z today. Freezing levels should drop steadily from ~3400 feet to 1000-1400 feet by about 12Z on Tuesday.

We expect good precipitation overnight tonight with a lull during the day tomorrow (roughly 15Z on the 27th through 0Z on the 28th) then a reintensification overhnight again into Wednesday. Precipitation should wind down at around 0Z on on March 1st.

Paul Schultz has observed that the GFS has been handling this system very well and he has favored this info in his briefing.

Operations:
The last supplemental soundings at Sloughhouse and Reno will be at 16Z on Tuesday, February 27th. SMART-R will continue to run until 0Z on the March 1st (Wednesday at Midnight). With heavy snowfall predicted over much of the route between Auburn and Foresthill, Monday night into Tuesday and again Tuesday night into Wednesday -- the SMART-R crew should take special precautions. Paul Schultz has agreed to contact Steve Vasilov with 0Z model run update tonight to help with their planning. Safety first!

At the conclusion of this IOP, SMART-R will proceed to pack-up and head home as conditions permit.

Instrument Status:
It appears that a power supply may be out on the profiler at Sloughhouse. We'll see about getting a technician out there as soon as possible. We have been missing a few soundings at Sloughhouse as well; a firmware upgrade was just conducted - hopefully this will correct these issues. It appears that the Oakland soundings went off as planned (perhaps with a few delays). All's well with the Reno soundings. SMART-R has been running well.

Finally, this is also a reminder that we'll have a long-term weather discussion on Tuesday's call.

T. Schneider

February 26, 2007

Project Status: 25 Feb 2007 (IOP7; Sunday Evening)

Precipitation rates throughout the region have slowed over the evening. Alta still hovering a couple of tenths of a degree C above freezing, whereas Blue Canyon is nearly -3C. Total snow depth at BLU is ~21 inches since the beginning of the IOP. Some updated liquid equivalent totals: 2-3 inches at Big Bend, Norden and Onion Creek, 2.4 inches at Alta, 1.6 inches at Colfax, 2.1 inches at Foresthill, 0.6 inches at Sloughhouse and 0.5 inches at Truckee.

Steve Vasilov relayed that Les Showell has reported 3 periods of 50+ dBZ echoes over Foresthill and "pea size hail, probably graupel." Gordon Carrie passed along the following image from earlier this evening as the intense band of precip approached the ARB (image from 21:25 UTC, 25 Feb 07):

SR2.20070225.212616.DBZ copy.tiff

No change in status with respect to the Sloughhouse profiler.

T. Schneider

February 25, 2007

Project Status: 25 Feb 2007 (IOP7; mid-day Sunday)

IOP7 is going strong. The freezing levels have remained relatively constant at ~3500 feet +/- (roughly, just above Alta (ATA) which is hovering a few tenths to 1 deg. above 0C). SMART-R crew reported an inch or so of wet snow overnight at Forest Hill (FHL) that has since melted; current precip at FHL is rain with occasional sleet. Rain continues to fall at lower elevations and Blue Canyon (BLU) has added 17" of snow since 0Z. SMART-R shows a band of precip (w/45 dBZ echoes embedded) heading towards the ARB, out at about 50 km range (also visible on KDAX).

The latest forecast calls for freezing levels to remain in the 3300'-3700' range until FROPA which is expected at ~0Z Feb 27th (~4pm Monday, local time) at which point they will drop. The IOP7 end game is a question mark at this time as the models disagree about what will transpire from Tuesday night into Wednesday. No change in the operational plan for IOP7 is required at this time, we'll revisit this issue on Monday's daily status call at 11:30 PST.

Instrument Status Issues:
SMART-R crew reports that the radar has been running well - no issues at this time. Overnight snow was light and wet and did not stick to the dish. Soundings in Reno are going according to plan. There were a few minor issues with the Sloughhouse (SHS) soundings, but are generally OK. No one is sure what is happening with the Oakland soundings (supplemental or otherwise), we'll look into it. The SHS profiler is still acting up and early this afternoon, a technician will attempt to diagnose the problems remotely.

T. Schneider

Project Status: 25 Feb 2007 (Sunday Morning)

IOP-7 continues. Since 00 UTC yesterday evening, a little more than a foot of snow has fallen at Blue Canyon. Snow levels started out around 4000-4500 feet, but have moved down to around 3500 feet. Some liquid equivalent totals so far: around 2 inches at Big Bend, Norden and Onion Creek, 1.5 inches at Alta, 1.3 inches at Colfax, 1 inch at Foresthill, 0.5 inches at Sloughhouse and 0.25 inches at Truckee.

Instrument status issue: The profiler at Sloughhouse started to malfunction yesterday evening at about the time the IOP start (around 01 UTC). Efforts will be made today to diagnose and fix the problem remotely. Also, heated tipping bucket precip gauge at Blue Canyon is still capped and probably will remain that way through the rest of the IOP given the temperatures we are expecting.


Kingsmill

Project Status: 24 Feb 2007 (Saturday Evening)

Light precipitation moved into the American River Basin around 23 UTC (24 Feb) and increased in intensity around 01 UTC (25 Feb). SMART-R operations started at approximately 01 UTC. Therefore, the official start time for IOP-7 is 01 UTC 25 Feb. Sounding operations have just begun with the releases for the 04 UTC sondes.

A few instrumentation notes:

1) The heated tipping bucket gauge at Blue Canyon appears to be capped. This behavior started during IOP-6. It is possible that the heating element for the gauge has failed. Although its data are not displayed, there is a hot-plate gauge at Blue Canyon that is collecting data.

2) As this long event proceeds, the SMART-R crew will have to stop scanning occasionally to brush snow off of the radar antenna.

Kingsmill

February 24, 2007

Project Status: 24 Feb 2007 (Saturday)

Conditions are shaping up for an extended precipitation event in the northern Sierra Nevada over the next several days. With snow levels at or below 4000 feet throughout the event, the 5-6 inches of liquid equivalent should translate into lots of snow, which should cut into the snowpack deficit. IOP-7 will commence this evening.

A few small showers are evident at present over the valley (between Marysville and Oroville) and spotty weak echoes in the American River Basin. It is expected that the echoes will increase in areal coverage later this afternoon, with precip rates increasing quite a bit after local sunset (01-02 UTC 25 February). SMART-R operations will start at around 01 UTC and four-hourly sounding operations from Sloughhouse will start at 04 UTC (03 UTC release). Four-hourly supplemental sounding operations from Reno and Oakland will also start at 04 UTC. Sounding operations from Sloughhouse and Reno are scheduled to continue through 20 UTC 27 February (noon Tuesday) while the supplemental sounding operations from Oakland will stop after 20 UTC 25 February (noon Sunday).

February 23, 2007

Project Status: 23 Feb 2007 (Friday)

Except for a few pesky shallow showers in the mountains, the precipitation from our most recent event has ended. IOP-6 officially ended at 04 UTC 23 February, but SMART-R operations ceased at 22 UTC. At mid to upper levels of the American River Basin, storm total precipitation (liq equiv) was around 2 to 2.4 inches. Blue Canyon received about 15 inches of snowfall. In the valley, precip totals were under an inch. The snow level eventually sank below 3000 feet and deposited some snow at our Colfax observing site.

Now our attention turns to the next precipitation event forecast to impact our domain. The models have been fairly consistent in suggesting an extended period of precipitation beginning Saturday evening and ending Tuesday evening, with a quasi-lull in activity (but not cessation) late Sunday into early Monday. Liquid equivalent precipitation totals for the anticipated 72 hour event are likely to exceed 5 inches. And, with the relatively low snow levels (hovering around 4000 feet through Monday evening, then diving down to maybe 2000 feet on Tuesday), this storm should be quite a snow producer.

This storm is certainly IOP-worthy. Therefore, we will declare IOP-7. Soundings from Sloughhouse will commence at 04 UTC 25 February (Saturday evening) and be released at 4-hour intervals until 20 UTC 27 February (mid-day Tuesday). Four-hourly supplemental soundings from Reno will also start and end at these times. In addition, four-hourly supplemental soundings from Oakland will be released at 04, 08, 16 and 20 UTC 25 February (Saturday evening into Sunday mid-day) while staff are available during the weekend to make the launches. SMART-R operations will likely commence Saturday evening--we will provide more specific guidance after our coordination call on Saturday. The SMART-R crew should be prepared for long duration operations that will likely extend into Tuesday evening. They should also be prepared for snowfall at Foresthill and along the road from Foresthill to Auburn, especially later in the event (Monday night into Tuesday).


Kingsmill

Status: 22FEB07 (Thursday - sunset)

IOP-6 is winding down and will end with the final soundings from Sloughhouse and Reno at 04 UTC 23 Feb (8 pm) tonight. SMART-R ended its data collection at 22UTC on 22FEB after the snowfall stopped at Foresthill and over most of the ARB. Since then some convective snow showers have popped up and are adding minor additional amounts of snowfall. The trough aloft has moved onshore to central California and pecipitable water vapor now stands at 0.4 inches, or about half of its peak value earlier today. Precipitation accumulations (liq equiv) for the IOP include 1.30 inches at Blue Canyon (from the ALERT gauge) with about 10 inches of snowfall, 1.20 inches at Foresthill with 7 inches of snowfall, 1.50 inches at Big Bend (Yuba Gap), 1.25 inches at Alta, 0.80 inches at Colfax, and 0.50 inches at Sloughhouse. Except for Sloughhouse, all of these stations received snowfall today from this cold system.

The next storm - and possible IOP - is predicted to move into the ARB Saturday evening. The project field effort has 4 weeks remaining; SMART-R has 1 week remaining.

- Martner

February 22, 2007

Status: 22FEB07 (Thursday - midday)

IOP-6 continues as heavy (4-star) snow falls in the ARB down to altitudes of 2.5 kft, including 6 inches at Foresthill. However, the swath of precipitation has a sharp back side as indicated by radar and satellite, so the heavy precip should shut down fairly abruptly by this evening. Cold fropa occurred at SHS around 13 UTC this morning. Therefore, we will not need to continue the soundings nearly as long as anticipated yesterday.

The last soundings from Sloughhouse and Reno are now scheduled for 04 UTC on 23FEB (8 pm tonight). That will conclude IOP-6, even though some very light, showery precip may linger in the area for several hours longer. The SMART-R crew should also continue data collection until 8 pm tonight, unless the precipitation has clearly ended sooner than that.

System repair successes:
SMART-R has been working fine, but the crew has to sweep snow off the antenna regularly. The ESRL/GSD hi-rez model package is back on line.

System problems:
Three of the SHS soundings lost signal very early. Corrective steps are being tested, in consultation with Visala. The precip gage at Blue Canyon appears to have bridged over with snow very early in the event. Realtime communications to the ESRL sites at Colfax and Truckee have been recently lost, perhaps due to snow on the comm antennas - the data are preserved in the on-site computers. The rain gage at Healdsburg apparently failed completely in this storm.

Outlook:
The forecasters are expecting a break in the action on Friday into Saturday. But by Saturday evening another storm begins to hit the ARB. This one is likely to be cold and prolonged (72-hours) with QPF of 4-6 inches liq equiv. possible. It is probable that IOP-7 will be conducted on some portion or all of that oncoming storm. Supplemental soundings from Oakland (on the weekend only) and Reno and Sloughhouse might be needed. SMART-R crew (Showell and Carrie) need to be ready for operations as early as Saturday afternoon/early evening. Decisions regarding these items and start times will be forthcoming, possibly on tomorrow's (Friday's) conference call.

- Martner

Status: 22FEB07 (Thursday - sunrise)

IOP-6 is in progress with orographic snow and rain over the ARB finally underway. Precipitation began at Blue Canyon around 06 UTC (10 pm last night) and has accumulated only 0.1 inches of liquid equivalent from snowfall there so far. Colfax has had about 0.1 inches of rain. However a strong cold frontal rain band oriented N-S, with reflectivity of 45 dBZ, is crossing Sacramento and the Central Valley now and should soon intensify precip over the ARB. Cazadero in the Coast Range has picked up about 2 inches of rain from the storm so far. The ESRL/GSD hi-rez model products are back on line and indicate about 1.5 inches QPF for Blue Canyon by late tonight. The melting level aloft is near 3.7 kft and has been descending rapidly.

SMART-R began collecting continuous data at 23 UTC (7 pm) last night and has been working fine. Soundings from Sloughhouse and Reno at 4-hr intervals and operations of SMART-R will continue today and through tonight.

- Martner

Status: 21FEB07 (Wednesday - sunset)

IOP-6 continues in progress, but the storm is agonizingly slow to arrive at the ARB. It is at least 12 hours behind yesterday's forecasted schedule. However, NEXRAD finally shows echo forming over the basin. Meanwhile, the main part of the storm has been parked over California's North Coast all day, where 2-4 inches of rain have fallen in the coastal mountains. So there is still good hope for substantial precip in the ARB tonight and tomorrow. Soundings from Sloughhouse and Reno will continue at 4-hour intervals, and SMART-R will contine to monitor.

- Martner

February 21, 2007

Status: 21FEB07 (Wednesday - midday)

IOP-6 is in progress, but the storm is weaker and considerably slower than predicted yesterday. The onset of precip in the ARB is now not expected before about 4 pm today. Nevertheless, today's models are still predicting 1.5 to 2.5 inches of precipitation (liq equiv) from this system by Friday afternoon. Snow level should drop from 5 kft today to 1.5 kft on Friday. Sloughhouse and Reno soundings have been going up at 4-hr intervals since 12 UTC this morning, and will continue. SMART-R is set to go, but will hold off on data collection until the precip approaches the foothills. No rainwater chemistry sampling is being conducted in this storm. IOP-6 operations are expected to continue into Friday.

Problems (besides a sluggish storm):
There is a computer problem for the ESRL site at Cazadero in the Coast Range; manual intervention is being considered to solve that. The ESRL hi-rez model package suffered a major outage when a new compiler crashed on Monday and shut the system off since then. Availability of SHS soundings on the ALPS workstations in Monterey and CNRFC is still an issue. GSD is working to solve these problems.

The outlook for the next storms includes a weak (QPF ~ 0.6 inches) weekend event, followed by a more promising (QPF ~ 2.6 inches) storm on Tues. ECMWF has the second storm looking even stronger.

- Martner

Status: 21FEB07 (Wednesday - morning)

IOP-6 began with the soundings from Sloughhouse at 12 UTC (4 am) this morning, but the storm is off to a very slow start. Precipitation has not yet reached the ARB, with the nearest stations reporting rain being Red Bluff and Cazadero, as of 7 am. Forecasts from HPC indicate only a few tenths of an inch of precipitation will fall today, but almost 3 inches of liq equiv will arrive on Thursday. The SMART-R crew fixed the truck's battery yesterday and they will begin scanning and collecting data later this morning as the precipitation moves into the foothills. Soundings from Sloughhouse and Reno will be launched at 4-hour intervals.

- Martner

February 20, 2007

Status: 20FEB07 (Tuesday)

The approaching storm will be the focus of IOP-6. This will be another prolonged period of precipitation (Tues night - Friday afternoon). It will also be colder than other IOPs so far this winter; the snow level could reach as low as 1000 ft by Friday. Overall, 3-5 inches of liquid equivalent is expected for the ARB region, although the plume of vapor is not so impressive with this system.

Although very light precip may arrive at the ARB earlier, the soundings from Sloughhouse will begin at 12 UTC on 21FEB (4 am Wednesday) and will continue at 4-hour intervals until as late as 00 UTC, 24FEB (4 pm Firday). Supplemental soundings from Reno will begin at 16 UTC, 21FEB (8 am Wednesday) and continue at 4-hour intervals through 20UTC 23FEB (noon Friday). The SMART-R crew should be ready to begin data collection by 12UTC on 21FEB (4 am Wednesday), but they can fine-tune this start-up time as the weather approaches the foothills. Repairs to the SMART-R truck battery need to be completed today. No rainwater chemistry sampling will be conducted, because the QPF is not as high as desired for that work and the likelyhood of snow at Alta would be problematic.

Another storm is predicted for the weekend, but currently looks to be too weak for an IOP.

- Martner

February 19, 2007

Status: 19FEB07 (Monday)

Yesterday's wave did not produce any measurable precip at Blue Canyon. Thus, Friday's decsion to forego an IOP on that wave was good and saved the project some resources to devote to upcoming storms, such as the one that will hit the ARB this week.

The forecasts are calling for a prolonged period of precipitation, stretching from Tuesday evening to Friday afternoon. Heaviest rain is expected Wedensday night to Thursday morning. Precip accumulations may reach 5 inches for the whole event. The snow level will descend from around 6 kft Tuesday night to 2 kft by Friday morning.

IOP-6 will be conducted on this storm. The SMART-R crew (Jorgensen and Showell) should travel to Sacramento tomorrow, work on the truck's battery problem in the afternoon, and be ready to start collecting data around midnight (08 UTC, 21FEB). Soundings from Sloughhouse and supplemental soundings from Reno will also begin at 08UTC, 21FEB (Tuesday midnight), and will continue at 4-hour intervals through 00UTC, 24FEB (4 pm Friday). Light rain might occur before the first sounding, but that's ok. The end time for soundings may be earlier, if the storm moves out sooner than currently predicted. No rainwater sampling for chemical analysis has been requested by USGS for this storm.

- Martner

February 18, 2007

Status: 18FEB07 (Sunday)

Today's weak sytem may drop up to 0.5 inches in the ARB for HMT's unattended instruments to monitor. The next storm for this week looks much wetter, with QPF values in the 2.5-4.5 inch range, and a narrow plume of precipitable water vapor aound 1 inch. It is very likely that we will conduct IOP-6 on this storm. The models show precipitation from this storm beginning in the ARB late Tuesday night or before dawn on Wednesday morning. The heaviest precip is predicted to fall between Wednesday afternoon and Thursday morning. Following a lull on Thursday afternoon, precip may intensify again Thursday night before ending mid-day on Friday. The snow levels are forecast to start near 5 kft and drop as low as 2 kft, so this storm will be colder than IOP-5.

The SMART-R crew (Jorgensen and Showell) should be prepared to travel to Sacramento no later than Tuesday afternoon. If more time is needed to work on the truck battery, that should be factored into their travel schedule. Soundings from Sloughhouse and supplemental soundings from Reno will be needed for this storm, perhaps as early as 00 UTC on Feb 21 (4pm Tuesday) . The start times for the radar and soundings, and the interval between soundings, will be decided at tomorrow's conference call, after giving ourselves another 24 hours for the storm's timing to come into sharper focus. Meanwhile, crews should be alterted and prepared for another fairly wet and prolonged outing.

- Martner

February 17, 2007

Status: 17FEB07 (Saturday)

The "storm" arriving at the ARB tomorrow is fizzling out; progs now only call for about 0.1 inches of precip from it. Much more promising is the next system which might hit the ARB as early as Tuesday night, but with the brunt of the precipitation in the Wednesday-Friday (Feb 21-23) time frame. This one has a strong, but narrow plume of vapor stretching back to Hawaii in the progs. HPC is expecting 2.75-4.5 inches of liquid equivalent in the ARB from that storm.

As was decided yesterday, there will be no IOP for tomorrow's storm. However, an IOP on the next one is starting to look likely. SMART-R operators should be prepared to travel to Sacramento as early as Tuesday afternoon, but travel on Wednesday morning looks more likely at this time. SHS and RNO soundings will probably be requested for this mid-to-late-week storm as well, but it's too early to figure out the start time yet. More on this tomorrow.

- Martner

February 16, 2007

Status: 16FEB07 (Friday)

A weak storm is predicted to bring 0.2-0.6 inches of precipitation to the American river Basin on Sunday (18FEB). This is expected to be followed by a stronger system in the Wednesday-Friday (Feb 21-23) time frame next week. The QPF for the Sunday storm is well below the HMT threshold, and does not warrant an IOP. Thus, no crew deployments are needed for this weekend, and the HMT unattended instruments will monitor that sytsem alone. The daily conference calls will continue, as usual, to update forecasts concerning the second system and beyond.

- Martner

February 15, 2007

Status: 15FEB07 (Thursday)

The next precipitation in the ARB is scheduled to arrive on Sunday (Feb 18), but currently looks too weak (QPF ~0.25 inches) for an IOP. We will make a decision on that possibility tomorrow. Another, stronger storm is expected to arrive next week on about Wedsday night (Feb 21). That one is more promising for an IOP.

The SMART-R has been granted a 5-day extension for the end of it's duty schedule at Foresthill, and can remain there for operations through March 2nd, if the weather warrants it. Crew staffing for those additional 5 days needs to be arranged.

Today's conference call included a 45-minute debriefing discussion of the storms for IOP-4 and IOP-5 (Feb7-11). Combined, these were big rainers, following a month of dry weather. The broad-stoke picture was handled well in the forcasts up to 7 days in advance, but details of the forecasts, which are crucial to water and emergency managers, were more problematic. An in-depth analysis of this case by the HMT partners would be instructive.

- Marnter

February 14, 2007

Status: 14FEB07 (Wednesday)

Dry weather is expected in the American River Basin for the remainder of this week. The outlook for next week includes two possibilities for storms. The first comes on Sunday-Monday, but currently looks too weak to meet our IOP theshold. The second possibility is in the Wednesday-Saturday timeframe (Feb 21-24) and looks like a better precipitation producer. Meanwhile, no crew deployments are expected before this Saturday.

The daily confernce call tomorrow (Feb 15) will be extended to include a debriefing discussion of the storms and operations for IOP-4 (7-8FEB) and IOP-5 (8-11FEB). What made those storms tick? How good/bad were the forecasts? What observations did/didn't work? Brief summaries to jog our memories are posted on the HMT project web page. Go to the left sidebar, "Project Information", and click on "Operations Summary".
Maps of precp forecasts during IOP-5 from the ESRL/GSD high-rez ensembles can be viewed at:
http://www-frd.fsl.noaa.gov/mab/hmt/nex18.cgi?%20init=1200z&date=10&month=Feb07 .
Movie loops from NSSL of the SMART-R low-elevation scans from Foresthill are available at:
http://www.nssl.noaa.gov/hmt06/IOP4.mov and http://www.nssl.noaa.gov/hmt06/IOP5.mov .

- Martner

February 13, 2007

Status: 13FEB07 (Tuesday)

The field work part of this winter's project is now 2/3rds over; SMART-R has only 2 weeks remaining. Oregon will get hit with a storm this week, but the outlook for the American River Basin is quite dry for the next several days. Thus, no crew deployments are expected in the next few days.

The SMART-R has been repaired and is being exercised at Foresthill today.

The daily confernce call on Thursday (Feb 15) will be extended to include a debriefing discussion of the storms and operations for IOP-4 (7-8FEB) and IOP-5 (8-11FEB). What made those storms tick? How good/bad were the forecasts? What observations did/didn't work? Brief summaries to jog our memories are posted on the HMT project web page. Go to the left sidebar, "Project Information", and click on "Operations Summary". Maps of precp forecasts during IOP-5 from the ESRL/GSD high-rez ensembles can be viewed at:
http://www-frd.fsl.noaa.gov/mab/hmt/nex18.cgi?%20init=1200z&date=10&month=Feb07

- Martner

February 12, 2007

Status: 12FEB07 (Monday)

The big 3-day storm on the weekend ended up with 8.72 inches of pecipitation (liquid equivalent) at Blue Canyon during IOP-5. The outlook for this week calls for no more than minor amounts of precipitation. Thus, no crew deploymnets are expected in the next few days. Repair work is in progress on the SMART-R radar at Foresthill today.
Woody Roberts of ESRL/GSD will try to figure out why the ALPS workstations at the California WFOs are not getting the Sloughhouse sounding data.

- Martner

February 11, 2007

Status: 11FEB07 (Sunday - midday)

Light precipitation continues in the upper reaches of the ARB as the storm finally moves out. Although showery precipitation may linger several more hours, IOP-5 will end at 20 UTC (noon) today with the final soundings from Sloughhhouse and Reno.

This prolonged storm had a good atmospheric river connection to the tropical Pacific with up to 3 cm of precipitable water vapor, which camped over the ARB. That vapor plume has now moved south to Baja, but it left behind large 72-hour rain accumulations in the HMT area, including approximately 8 inches at Blue Canyon, 6 inches at Alta and Foresthill, and 5 inches at Colfax. These amounts were predicted fairly nicely at the start of the event. In the Coast Range, Cazadero picked up 10 inches. Streamflow at the North Fork AR Dam near Auburn jumped from far below normal to well above normal (from about 150 to 11,000 cfs), during IOP-4 + IOP-5. The antecedent month of dry weather precluded any serious risk of flooding, however. Supplemental soundings from Reno went flawlessly throughout the IOP. Some of the soundings from Sloughhouse had troubles. SMART-R was only able to cover the first day of the IOP, with holes, before its failure. Repair work is scheduled for the radar on Monday. Tyler Coplen of the USGS ran himself ragged between Alta, Bodega Bay and Cazadero setting up rainwater samples for chemical analysis. With some help from ESRL folks in Colorado, especially Dave White, it looks like the sampling was very successful in this IOP. We may schedule a debriefing for IOPs 4 & 5 on the conference call about mid-week to discuss the storm and ops.

The weather outlook now calls for mostly dry weather in the upcoming week. Thus, no crew deployments will be needed for at least a few days.

- Martner

News Story About HMT

In the midst of this nice IOP, KGO/ABC7 TV (the ABC affiliate in San Francisco) did a story on our HMT project. You can see the piece and read about it at:

http://abclocal.go.com/kgo/story?section=weather&id=5020322

The KGO crew visited the JOC in Sacramento and interviewed John Juskie and Art Henkel. I then took them out to see the equipment at Sloughhouse (they wanted the closest site). While the story does not get everything just right, it does capture some of the salient features of the HMT project in a favorable light.

I would like to thank our colleagues at the RFC and WFO in Sacramento for being gracious hosts and for putting up with the intrusion into their important work. This kind of outreach is one of the few outlets we have for sharing our important work with the people who pay for it and benefit by it.

-T. Schneider

Status: 11FEB07 (Sunday - sunrise)

IOP-5 continues as the precipitation begins to wane. A cold front at the surface passed through the ARB before dawn around 10 UTC, but precipitation continues at Blue Canyon and other locations.

Soundings at Sloughhouse and Reno will continue through 20UTC (noon) today. That will mark the end time for IOP-5.

- Martner

Status: 10FEB07 (Saturday evening)

IOP-5 continues on this marathon storm which has had a good atmospheric river connection to the tropical Pacific. Rainfall totals thus far for the IOP include approximately 6 inches at Blue Canyon, 5 inches at Alta, and 4.5 inches at Colfax and Foresthill. In the Coast Range, Cazadero has had 10 inches of rain. A convective N-S-oriented rainband with 50 dBZ centerline has formed south of Auburn as cooling aloft destabilizes the flow. GPS-Met precipitable water vapor values dropped off from peak of about 3 cm earlier today to 2 cm. Today's steady decline of surface pressue has ceased with the approach of the storm's back end cold front.

Soundings at Sloughhouse and Reno will continue through 20 UCT on 11FEB (noon Sunday).

- Martner

February 10, 2007

Status: 10FEB07 (Saturday - midday)

The storm and IOP-5 continue. It is about 2/3rds over now. Rainfall has been remarkably steady at Blue Canyon and has accumulated about 4.8 inches in the last 48 hours there. The forecasts are calling for about 3 additional inches in the next 24 hours or so. After that, not much chance for IOP-level storms for the next several days.

The SMART-R radar is out of action for the remainder of IOP-5. Engineer, Jerry Guynes is flying out from Texas on Sunday evening and he will try to fix the radar in place at Foresthill on Monday, with Kevin Manross assisting. Bruce Bartram returns to Colorado tonight. Meanwhile, the soundings will continue to document this nice atmospheric river event. Soundings at Sloughhouse and supplemental soundings at Reno wil continue at 4-hr intervals through 20UTC on 11FEB (noon PST on Sunday).

Radio and TV coverage of the project during this storm was good, we hear, including footage at the CNRFC and of our sounding crew at Sloughhouse.

- Martner

Status: 10FEB07 (Saturday - sunrise)

The prolonged storm continues with steady, moderate precipitation rates over the ARB. IOP-5 continues to monitor it with radiosonde launches at Sloughhouse and Reno, rainwater chemistry sampling, and the many unattended HMT instruments. Unfortunately, the SMART-R radar has been down since yesterday afternoon and is unlikely to return for this storm (see last night's status). Rain totals for the storm so far include approximately 4.5 inches at Blue Canyon, 3 inches at Foresthill, 0.5 inches at Sloughhouse, 0.4 inches at Truckee, and in the Coast Range 7.3 inches at Cazadero. HPC is predicting 3 more inches in the ARB by Monday morning, when the precip should finally end. Definitely the biggest storm of the winter so far. The melting level has hovered around 7900 ft for the last 24 hours, according to the S-band profiling radar at Colfax.

We plan to continue the sonde launches every 4 hours at Sloughhouse and Reno, in spite of the SMART-R outage.

The SMART-R engineer is sending parts out and he will arrive from Texas on Sunday night. He and Kevin Manross will try to get the radar repaired on Monday.

- Martner

Status: 9FEB07 (Friday evening)

The storm and IOP-5 continue, but without the SMART-R radar. Kevin Manross reports that the radar's antenna controller problem worsened and forced the radar out of action by this afternoon (2140 UTC 9FEB). The crew tried many work-around solutions and consulted with the radar's designer by phone, but to no avail. Thus, it looks like there will be no SMART-R data until a major repair is scheduled, probably too late for this storm. Meanwhile IOP-5 will continue with soundings at Sloughhouse and Reno and water chemistry sampling at least until midday tomorrow when we will reassess activities on the daily conference call. Blue Canyon has 3.5 inches of liq equiv from the storm thus far.

- Martner

February 09, 2007

Status: 9FEB07 (Friday - midday)

IOP-5 began at 20 UTC on 8FEB and continues to monitor a big, warm storm, which is expected to last another two days. NWS issued a winter storm warning, but no flood problems are anticipated, thanks to a month of dry weather preceeding this week. The IOP-5 storm's precipitation accumulations (liq. equiv.) already exceed 2.5 inches at Blue Canyon, and are approaching 2 inches at Colfax and Foresthill. Snow levels have been 6-7 kft. Cazadero in the Coast Range has already been drenched by 5 inches of rain.

Forecasts call for quite a lot more precipitation (QPF values of 3-4 inches additional) before the storm moves out of the ARB on Monday morning. More than 3 feet of snow may be still ahead for the very highest altitudes. No prolonged breaks in the precipitation are predicted by the models. The back-end cold frontal passage is predicted to arrive around 18 UTC on 11FEB (10 am Sunday) and precipitation should end 12-18 hours later.

Soundings at Sloughhouse and Reno have been mostly good, and will continue at 4 hour intervals. Currently we expect these launches to continue through 20 UTC on 11FEB (noon Sunday). The SMART-R radar has been having trouble with its antenna controller, causing occassional 15-30 minute data outages. The SMART-R crew will continue operations, as best they can, and should expect to be on duty through Sunday night. Rainwater chemistry sampling is in progress by USGS at Alta, Bodega Bay and Cazadero, but the equipment electronics at Cazadero got swamped and its continuing health is uncertain. ESRL's high-resoltion model ensembles failed to be produced this morning.

Botttom line: This is the biggest storm of the winter so far and IOP-5 will continue to cover it, in spite of some mostly minor problems.

- Martner

Status: 9FEB07 (Friday - sunrise)

IOP-5 is in progress. Good preceip liquid equivalent amounts already at ESRL gauges in the ARB, including approximately 2 inches at Blue Canyon, 1 inch at Foresthill, 1 inch at Colfax, 1.5 inches at Big Bend, 1 inch at Onion Creek (from snowfall), 0.2 inches ar Truckee, and 0.25 inches at Sloughhouse. Also 1.5 inches at Bodega Bay and 4 inches at Cazadero on the coast. HPC is predicting about 5 additional inches in the ARB between now and Monday morning.

S-band profilers show the freezing level has been near 6800 ft during the night. GPS-Met monitoring of precipitable water vapor showed peak values of 2.9 cm at Bodega Bay and 2.7 cm at Sloughhouse. Wind profilers show strong SW (upslope) flow above about 1 km MSL, but S flow in lower altitudes.

- Martner

February 08, 2007

Project Status: 8 Feb 2007

Weather Status: IOP 4 came to an end at 9:20GMT on 8 Feb. Rainfall amounts almost made an inch (0.99 at Blue Canyon), but for the most part amounts over the ARB were less than that. Still, it was a good opportunity to get the systems up and running again. SMART-R ran flawlessly through the event. NSSL put together a nice radar loop documenting the event. IOP 5 start looks good with the sounding releases at Slough House and Reno beginning at 20 GMT/8 Feb. Precip should start sometime between 8/21GMT and 9/00GMT. The approaching trough does have a IPW river in association but amounts are less than expected from yesterday's models. Still the event will produce 3-5 inches of rain with the maximum rate near 9/18GMT. SAC has issued a winter storm warning for the mountains above 6000ft. There is a short break indicated in some forecast models between 10/03 and 10/18GMT as the first minor wave moves east and the onset of the major trough. Cold frontal passage with the major trough looks to be sometime near 11 Feb/06GMT but timing is not exact. Plan is to run sondes one cycle past the cold frontal passage. This will be updated at tomorrow's telecon. This system should continue to Sunday afternoon (11 Feb/21GMT). Next event isn't until 15 Feb.

System Status: SMART-R running well; First sondes have been released for IOP 5. Rain sampling is underway at Cazadero and Bodega Bay. Power outage at Big Bend has started and should be completed by late afternoon. Problems were encountered with ensemble products getting to the ALPS workstation at MRY; there appears to be a problem getting the high resolution model products using MS Explorer version 7.0. Earlier versions (6.x) appear to work. Tim Schneider will host the media for site visits and HMT interviews.

Operational Decision Summary: Radar for IOP 5 begins at operator discretion; Sondes are underway at RNO and Slough House. They will continue until at least Saturday night/Sunday morning (11 Feb/10GMT). Stay tuned for an update at tomorrows HMT telecon.

John McGinley ESRL/GSD

February 07, 2007

Project Status: 7 Feb 2007

Weather Status: IOP 4 began with the start up of the radar at 16GMT on 7 Feb. Rain began in the ARB this morning so forecast timing was good. AT 18GMT radar indicated a prefrontal band moving into the Sierras. Some concern exists for the track of the surface low which is more northwest than expected. This could reduce the amount of precipitation over the ARB. Both NWS and HMT forecasters felt this would be a marginal event (<1"/24 hrs).Current conditions at the SMART-R radar site that it was raining steady, however observed gauge amounts only indicated near 0.1 as of 7/18GMT. The 36 hr high resolution ensemble indicated a 60% chance of an inch or more at some location in the ARB, with a 20% chance of 2 inches. The ARB should see the cold front pass by 8 Feb/06GMT, with the precipitation tapering off through 12GMT. Snow levels should be above 5500 ft lowering to 4500 ft by the end of the event. End of IOP 4 will likely be between 8/06GMT and 8/12GMT.

IOP 5 - Timing of the arrival of the second event is somewhat uncertain in the model forecasts with the GFS predicting the onset of rain in the ARB for 9 Feb/00GMT. This is clearly will be a warm advection event with a high IPW river aimed right at central CA. The current UH GFS forecasts indicate that this band is a bit weaker than yesterday. Thus, yesterday's GFS forecasts of 8-9 inches by the end of the event will be somewhat reduced in todays outlook perhaps in the 3-5 inch range. HPC identified some disagreement in the SRF ensemble. This set of forecasts had the precipitation maxima spread out from NW CA to the southern Sierras. IOP 5 will offically get underway at 20GMT 9 Feb with the first sonde releases at Reno and Slough House.

System Status: SMART-R is running well and is fully manned. Soundings were delayed for IOP 5 owing to adjustments in weather timing. Soundings will start mid-day Thursday. Final raingauge installation at Alta will take place today so sampling activity may begin with IOP 5. The Bodega Bay profiler was taken out by power system maintenance. Efforts are being made to get this back on line. A power outage is expected at Big Bend from 8 Feb 16GMT to 23GMT. Training was conducted today on probablistic products and the ALPS workstation. A web log has been estabished to record problems, comments, and recommendations on anything ALPS related: http://www-md.fsl.noaa.gov/eteam/HMT_evaluationsurveys/evaluationlogsurvey_HMT.html

Operational Decision Summary: For IOP 5, Slough House sondes will begin on 8 Feb/20GMT (12PST); Reno supplemental sondes begin on 8 Feb/20GMT. Both will be at 4 hour intervals and are planned to reach 70MB. Both sondes are likely to terminate 4 hrs (one sonde release) after the cold frontal passage for System 2 on Sunday. Timing of sonde temination will be discussed at the HMT telecon over the next few days.

John McGinley ESRL/GSD

February 06, 2007

Project Status: 6 Feb 2007

Weather Status: Model forecasts are in agreement that a major event will occur over the next 120 hrs. Specific details show there is some diversity of opinion in some model forecasts. Two systems will impact the ARB in the next 5 days. System 1 starts precipitation in the ARB around 16GMT on the 7th. Amounts from this cold-advection event will go over an inch. System 2 dominated by warm advection dynamics, will follow closely with only a 9-12hour break between events. A high IPW river is associated with this system. Precipitation starts up again mid-day on the 8th (18-21GMT) and is unlikely to abate until late Saturday or early Sunday (11 Feb at 12GMT). These start and ending times were well represented by the 3-km WRF-NMM running out to 72hrs. GFS amounts for the storm indicate 8-9 inches of rain in the area, with snowfall above 7500ft. Owing to the differences in the two events we will lable System 1 as IOP 4, and System 2 as IOP 5. In the long range additional troughs are likely through mid next week. Decisions on whether to pursue these will depend on the success of IOP 4 and 5.

System Status: Radar crews are traveling today for a start up late morning on Wednesday (Feb 7). Soundings at Slough House and supplemental soundings at Reno will be aimed at System 2 and begin Thursday morning (Feb 8). USGS rainwater sampling has good potential Thursday and beyond. Workstation and probabilisitic product training will be conducted at 9am PST. Dial the HMT meet-me number to tune in. Monterey reported exceedingly slow load times for model products on ALPS.

Operational Decision Summary: Commence SMART-R radar operations on Feb 7/16GMT (9amPST); Commence soundings at Slough House Feb 8/12GMT (4amPST); Commence supplemental soundings at Reno on Feb 8/16GMT (8amPST). All soundings will be at 4 hour intervals. Soundings are planned to 70MB. Termination of radar and soundings will be decided at the HMT telecon later in the week. Rainwater sampling for 48 hours should be done from mid-day Thursday to mid-day Saturday at all locations.

John McGinley, ESRL/GSD

February 05, 2007

Project Status: 5 Feb 2007

Weather Status: West coast ridge is finally out of the picture as it minors out and moves slowly eastward. All models in agreement that a first wave in a series of three or more, begins to bring precipitation into the ARB Feb 7 (Wed) in the morning. This first event is cold front driven with snow levels likely to be near 6000 ft. Models are indicating precipitation totals of close to an inch over the 18-24 hr period. A second wave close on the heels of the first moves in by Feb 8/12Z (Thurs). This one is likely to have a well defined atmospheric river in association, with the precipitation driven by warm advection. Models are indicating 2-3 inches by Feb 10. Snow levels expected to be just below 8000ft. Another event looks quite possible for 10-12 Feb. NWS WFOs in general agreement with this scenario. To reiterate: wave 1 - 7/15 to 8/06; wave 2 - 8/12 to 9/18; wave 3 10/06 to 12/00. Since we want to get a complete precipitation and hydrological record we will initiate IOP 4 beginning on 7 Feb (Wed) at 12GMT. Radar crews will travel on 6 Feb and be ready for operations Wednesday morning. Soundings will be delayed relative to the radar to capture the warm advection phase. Sounding will begin at Slough House and Reno on 8 Feb at 06GMT. These times will be examined and refined in tomorrow's update.

System status: An IOP 3 Summary has been posted on the HMT web site. USGS is installing rain sampling equipment to do chemical analysis on the rain at Bodega Bay, Cazadero, and Alta. The high resolution ensemble has been restored after some gaps caused by incomplete NAM files that serve at the background. Ensemble and workstation training is scheduled for 9am PST on Feb 7: Please dial in the meet-me number used for the daily telecon. Again, no supplemental soundings will be available at Oakland.

Operational decision summary: Travel 6 Feb; Commence SMART-R radar operations 7 Feb 1200GMT; Commence soundings at Slough House 8 Feb 06GMT, 3 hour intervals; Commence supplemental soundings at Reno 8 Feb 06GMT, 3 hour intervals. Sounding start times and interval may be updated at the HMT telecon on 6 Feb.

John McGinley, ESRL/GSD

February 04, 2007

Project Status: 4 Feb 2007

Weather Status: Demise of the west coast ridge still looks likely as door opens for potential IOP events later in the week. First system Wed Feb 7 will be weak and likely will not meet the precipitation criteria. NWS feels a good share of the forcing will go north of the HMT area. Better prospects are set for Friday Feb 9 with a second system likely to have a prolonged period of warm advection precipitation with a connected high IPW river. These systems are still well out in the central and western Pacific, but model consistency had been quite good with timing and intensity. If anything we have noted a tendency for the models to be a bit slow so this has moved potential IOP events back in time. So for today we can say no IOP for 72 hours.

System Status: No reports.

John McGinley, ESRL/GSD

February 03, 2007

Project Status: 3 Feb 2007

Weather Status: West coast ridge shows signs of beginning the breakdown process 5-6 Feb. It is shifting east and will be beaten down a bit by a weak shortwave. A sequence of systems 7 Feb, 9 Feb, and 11 Feb will likely bring precipitation to the HMT region. First wave loooks marinal at best with reduced runoff potential owing to extremely dry soil. These systems are still well out in the central and western Pacific and much can happen before they hit the coast. NWS recommends caution. UH IPW progs show a good river connection with the wave on the 9th. Each storm will bring a little bit more moisture aloft hinting at successivley more promising events as the sequence goes on. Earlier optimism about a system mid week is somewhat reduced, with better prospects as we near Feb 9 and the weekend. No IOP is expected in the next 3 days.

System Status: No reports.

John McGinley, ESRL/GSD

February 02, 2007

Project Status: 2 Feb 2007

Weather Status: Conditions similar to yesterday. Upper level ridge stationary and effectively blocking all troughs, shows signs of moving onshore 6 Feb. Trough begins to impact coast sometime after that. Best guess is 7 Feb. Beyond that, long range ensembles and models are showing the potential for 2-3 events up until 16 Feb. Outlook for week two indicates an MJO moving into the eastern Indian Ocean and consolidating with Indonisian convection that has been regenerating westward. Such a configuration feeds momentum into the westerlies that favor a further retrogression of the Pacific ridge. This may produce general troughy conditions off the west coast. This blends well with the long range NWP models, so signs are pointing to a more active period in Feb weeks 2 -3. So... for today no IOP, but prospects are looking up for the middle of next week.

System Status: MRY is having AWIPS problems related to relocalizations by NCF, necessitated by attempting to get MADIS data on the machines. This is not impacting the HMT ALPS workstation. Links to 3-km ensemble PQPFs are now on the HMT web page. Click on High Resolution Models then select the PQPF products.

John McGinley, ESRL/GSD

February 01, 2007

Project Status: 1 Feb 2007

Weather Status: Not much change in the situation as the upper ridge continues to be a prominent blocking feature off the coast. Long range forecasts are in agreement that the ridge moves westward at high latitudes allowing midlevel flow to begin to undercut and move into the coast. There is still much divergence among the models so the timing and details are unknown. Best guess today is a wave in the area on Feb 7. Models however, are ambiguous on whether this will be southern or northern CA. ECMWF indicates a possible series of events from the 7th to the 13th. Beyond that there is some indication from the longrange GFS ensemble that the ridge could try to reestablish itself. Don't want to hear this! Bottom line: no IOP for the next 5 days.

System Status: No reports today.

John McGinley, ESRL/GSD