HMT-West 2007: Project Status

Weather Status: Large amplitude blocking ridge still holds sway to the west of the HMT area. Dry conditions will continue for at least the next 5 days. Long range forecasts are indicating a general breakdown and shift east of this ridge some time in the 5-6 Feb time frame. Two models (Canadian and NOGAPS) have an event progged for 5 Feb. Other models GFS, ECMWF, and most GFS ensemble members are delaying this event. NWS is keeping precipitation out of the extended range forecasts at this time. Details of the regime change are still very much unknown. Much of the available forecasts and other tools are highly divergent at this time. So...no IOP expected in the next 5 days ( to 5 Feb), but potential exists for an event between 6-10 Feb.

System Status: Report from WR and SAC indicates that owing to personnel problems the OAK supplemental soundings will be unavailable for at least 4 weeks. Best scenario would see these available again in March. HMT and WR staff are exploring options to carry these un-used sondes over to next year's operations.

Posted by Status Editor at 07:50 PM | Permalink | TrackBacks (0)

Weather Status: The ridge off the coast will sustain northerly flow aloft over the HMT region. A few short waves imbedded in this flow could cause some episodes of very light rain. Looking forward, the ensembles and set of global models are indicating a change in the regime by 5-6 Feb. It is unclear, however, how this will evolve. WR indicated that there are many uncertainties with the Pacific flow. The ensemble set is highly variable in the timing of a particular system. So we look toward the weekend expecting a change to begin and will stick with the expectation of a possible IOP near the 6th of Feb. Beyond the 6th the flow is more zonal on the coast and thus the outlook for the second week of Feb might be for a very active period.

System Status: Workstation training for the high resolution model probabilities will be conducted the next time rain is in the area. This could be during one of the light rain events expected with the northerly flow regime. We will try to give 24h notice. Time will be at 9am PST as requested.

John McGinley, ESRL/GSD

Posted by Status Editor at 10:29 PM | Permalink | TrackBacks (0)

Weather Status: The closed-off low continues to drift southward and becomes more irrelevant to the HMT each day. Ridge off the coast continues to dominate the weather over central California effectively blocking any troughs or moist surges into the area. This looks likely to continue for the next 5-6 days. Some hope is on the horizon as each global model run and associated ensemble members are weakening the ridge and propagating it eastward after 4 Feb. Significant tropical moisture mid Pacific, continues to move east and north so could phase nicely with the eastward shift of the ridge and increased SW flow over the ARB. Westward redevelopment of the tropical convection in the W. Pacific near 140E will help to rerograde the longwave ridge to a position nearer the dateline at high latitudes. At the same time the short wave component of the ridge will move eastward. This supports the idea that upper level flow will undercut the longwave feature and become southwesterly over the coast and open the door for a possible IOP in the 5-6 Feb time frame.
System status: Monterey WFO has its workstation up and running today. Stage is set for workstation and model training for RNO, SAC and MTY (TBD). GSD ensembles running well. No updates on Oakland supplemental soundings.

John McGinley, ESRL/GSD

Posted by Status Editor at 07:54 PM | Permalink | TrackBacks (0)

Weather Status: Closed low on the coast this morning drifted further south than expected. IPW values are maxed out at 0.6 in. This produced precipitation well south of the ARB. This low has an imbedded short wave that will push precip a little further north today along the Sierras. The NAM and two GSD ensemble members suggest this, but again too far south. The closed off low continues to drift SE. It will entrain a weak short wave moving in from the north that will sustain its strength for a day or two. The only hope for an IOP is in the long term. All global models are indicating a full-latitudinal ridge off the coast staying in place through at least Feb 3. The good news is that subtropical IPW is increasing and moving north and east. Once the ridge gives way moisture should be ready to move into central CA. The GFS ensemble is looking optimistic as about half the members are indicating the ridge moving easward with decreasing amplitude, opening the door for WSW flow into the area 5-6 Feb. The bad news is that this means no IOP for more than a week.

System Status:Chris Anderson reported the problems with Jet have been corrected and the ensemble is up and running again at full capability.

John McGinley, ESRL/GSD

Posted by Status Editor at 07:42 PM | Permalink | TrackBacks (0)

Weather Status: The closed off low still off the coast, will make a pass inland through the next 24 hrs. This will bring IPW values near an inch as some subtropical moisture is drawn north out of Mexico, and likely some light precipitation to the ARB. Amounts should be less than 0.5 inches. Flow is from the southeast and thus not generating any upslope. High resolution model guidance showed a maximum of half an inch in the eastern portion of the ARB from 2 out of 3 of the microphysics members. Closed off low stays in the area through 84-96 hrs (31 Jan) then drops SE. All global models are in agreement with generation of a large west coast ridge that probably peaks about 1-2 Feb. 8-9 day GFS forecasts indicate that about 5 Feb the strong Pacific flow begins to undercut the ridge. A system on Feb 6 should bring in the first trough and significant shot of high IPW air. An IOP is not likely until we see a scenario like this....namely, a significant modification of the ridge.

System Status: Chris Anderson reported problems with Jet running the latest ensemble. He will monitor the 18 GMT run to see if it recovers. No other reports were received.

John McGinley, ESRL/GSD

Posted by Status Editor at 07:51 PM | Permalink | TrackBacks (0)

Closed off trough off the west coast continues to meander bringing some rain and showers to the coastal ranges. Forecast for this system is very uncertain. An optimum track could bring some rain to the ARB but only in small amounts. 3-5 day progs indicate a huge ridge building off the coast which will put the Sierras in northerly flow and completely cut off any hope of high Pacific IPWs flowing into the HMT area. Long range outlook does offer some hope as the convective clusters in the W. Pacific are starting to couple with the westerly jet bringing an increased flow of moisture further north and east. Best hope is for this enhanced flow to undercut the ridge finally opening the door to the subtropics. However, this is probably not likely until the Feb 4-5 time frame. The bottom line is that no IOP is likely for a week or more. Workstations have arrived at Reno and Monterey with installations under way. Plan is for workstation user training and ensemble training to occur sometime in the next week.

John McGinley, ESRL/GSD

Posted by Status Editor at 08:05 PM | Permalink | TrackBacks (0)

Cutoff low continues to wobble offshore of northern California. However, it really doesn't matter because there is so little moisture available for the dynamics to act upon. Therefore, no more than scant (maybe a tenth of an inch of liquid) precipitation is forecast for the American River Basin over the next day or so (if the cutoff decides to wobble onshore at all). Beyond this weekend, the next best chance of precipitation appears to be late next week into the following week.

Kingsmill

Posted by Status Editor at 07:06 PM | Permalink | TrackBacks (0)

Short-range model guidance has been erratic over the past couple forecast cycles, but the end result in terms of precipitation for the American River Basin over the next few days is the same----i.e., conditions will remain dry. The next chance for precipitation in our domain appears to be around 2 February. Ed Berry and Klaus Weickmann will lead a more extended long range forecast discussion during our call on Friday.

Status issues--

Oakland supplemental soundings: Staffing issues at Oakland still preclude us from requesting supplemental launches from that site. Resolution of the staffing issues may occur over the next few weeks--expect an update in about 10 days.

HMT-West 2007 web page: The HMT-West 2007 web page has just been updated to include space for an image that allows recent activities/analyses/efforts/imagery etc associated with HMT-West to be highlighted. It is on the upper right hand portion of the main page and can be updated daily, if desired. This dynamic element will help keep the page fresh. To start, there is an image containing time series of precipitation from four of our HMT-West 2007 sites since the start of the project. Please provide suggestions for other aspects of HMT-West 2007 to highlight.

Kingsmill

Posted by Status Editor at 07:28 PM | Permalink | TrackBacks (0)

Yes, it's still dry over the American River Basin. The possible light precipitation that has been forecast to occur in our domain sometime during the Thursday-Saturday period is becoming even more unlikely than thought during the past couple of days. Model guidance suggests that the next possible weather system that could affect our domain may occur late next week (around 2 Feb) and then another possibility the following week (around 7 Feb).

Status update--

The ALPS workstations for Reno and Monterey were shipped today from Boulder and should arrive on Wednesday (24 Jan).

Kingsmill

Posted by Status Editor at 07:25 PM | Permalink | TrackBacks (0)

Presently dry over the American River Basin, a condition that will persist into at least Wednesday. The Thursday-Saturday time frame this week may offer some very light precipitation, but liquid equivalent accumulations probably would not exceed 0.1 inches. Thereafter, a formidable ridge builds along the west coast with dry weather forecast into the second week of February.

No status updates to report at this time

Kingsmill

Posted by Status Editor at 07:29 PM | Permalink | TrackBacks (0)

Still dry in the American River Basin. There are hints of a weather system that could impact our domain late this week, but it is manifest only at mid-upper levels with virtually no surface reflection so it will likely be moisture starved. It is very unlikely that this system will produce precipitation. Thereafter, the long range continues to indicate dry conditions into at least the second week of February.

No status issues to report at this time

Kingsmill

Posted by Status Editor at 07:33 PM | Permalink | TrackBacks (0)

Not much change in the forecast. Still expecting dry conditions in the American River Basin for a while. There is a slight chance of precipitation in our domain at the end of next week, but if it occurs, it would most likely be a short duration and low QPF event. After that, the models are very pessimistic about precipitation in our domain going out to early February.

Kingsmill

Posted by Status Editor at 07:26 PM | Permalink | TrackBacks (0)

Conditions in the American River Basin continue to be dry. Medium to long range model forecasts indicate that this trend will continue for at least the next two weeks. Ed Berry and Klaus Weickmann suggest that there is an evolving pattern in the tropcial western Pacific Ocean that may create a more favorable (i.e., wet) weather pattern for California in about 15 days.

No status issues to report today

Kingsmill

Posted by Status Editor at 07:46 PM | Permalink | TrackBacks (0)

Dry and cold conditions continue over the American River Basin. Model guidance suggests that this condition will continue into at least the latter part of next week.

Status issues--

ALPS workstations: Workstations for the CNRFC and Sacramento WFO have already been installed. Workstations for Reno and Monterey will be shipped tomorrow or Monday (22 Jan). The current plan is for installation and training to occur remotely (i.e., no site visits by GSD staff)

Oakland supplemental soundings: The Oakland upper air contractor has identified a new observer. There have been delays in hiring this person that may be resolved in about 10 days. Once this person has been hired, it is anticipated that Oakland should be able to comply with requests for supplemental soundings.

Winter storms reconnaissance program: The goal of the Winter Storms Reconnaissance (WSR) Program.is to deploy spatially and temporally targeted dropsondes well out over the Pacific from aircraft flying out of Honolulu and Anchorage -- with the objective of improving the NCEP model forecasts in critical weather situations, especially when there is significant model disagreement or uncertainty. For the western U.S., the constraints of the program are such that the forecast event of interest would typically have to be identified 60-96 hours in advance (for a request to be made for targeted obs). The Monterey Forecast Office is serving as the Western Region Coordination Office for this season.

Posted by Status Editor at 07:30 PM | Permalink | TrackBacks (0)

The 500 mb cutoff low passed over San Francisco Bay today as forecast. Some light precipitation offshore and along the coast occurred; there was perhaps a trace of precipitation over the American River Basin. The cutoff low has now moved down toward southern California. Radar depicts a few showers off of Pt. Conception and along the coast near Santa Barbara.

Model guidance still suggests dry conditions will prevail in our domain for the rest of this week and into at least the early to middle part of next week.

Kingsmill

Posted by Status Editor at 07:41 PM | Permalink | TrackBacks (0)

Still dry and cold over the American River Basin today. Chances of precipitation in our domain for the next few days still look bleak. Today's 12 UTC model output positions the cutoff low a little further east (basically over Oakland) compared to yesterday's 12 UTC model output. However, the model's still do not generate much if any precipitation over our domain---the precipitation that falls (and it won't be that much) will be mainly restricted to the coastal zone. In the longer term, prospects for significant precipitation in our domain are slim for at least the next 10 days. Ed and Klaus will provide a more extended longer term discussion on Friday of this week.

Workstation status issue--

The workstations for Reno and Monterey were shipped from Boulder last Friday (12 Jan) and should arrive today or tomorrow. Current plans call for installation and training to occur via telephone.

Kingsmill

Posted by Status Editor at 07:25 PM | Permalink | TrackBacks (0)

Dry and cold over the American River Basin today. The weather system for mid-week will stay mainly offshore of northern California, perhaps influencing the coastal mountains but nothing for our domain. By late week, it will move down toward southern California. Timing on progression inland is not clear. In the longer term, there are hints that the subtropical jet will intensify during the week of 22 January, but the core of the jet looks to be south of the California-Mexico border.

No status updates to report at this time

Kingsmill

Posted by Status Editor at 07:29 PM | Permalink | TrackBacks (0)

Mainly dry over the American River Basin at present. There is a possibility of some light showers along and east of the Sierra crest this afternoon and tonight, but they shouldn't amount to much. The weather system that was forecast yesterday to possibly impact our domain during midweek will likely take a track southward along the coast down to southern California, without penetrating inland. In other words, chances for midweek precipitation of any significance (i.e., more than just spotty, short-duration showers) in our domain are very slim. At this time, an IOP for the event is very unlikely.

No status issues to report at this time

Kingsmill

Posted by Status Editor at 07:27 PM | Permalink | TrackBacks (0)

Presently dry over the American River Basin. Some light showers might develop Sunday into Sunday night, but mainly along and east of the Sierra crest---the ARB will be downsloping, so probably not much there.

The models are advertizing a more substantial weather system for the middle of next week compared to forecasts from the past couple days. Timing from today's 12UTC GFS suggests precipitation in our domain sometime during the Wednesday-Thursday period. Precip amounts for the ARB don't look particularly impressive; larger amounts are forecast for the coastal mountains. However, this is an encouraging trend compared to forecasts from the last few days. Certainly something to keep an eye on over the next several forecast cycles.

No status issues to report

Kingsmill

Posted by Status Editor at 03:44 PM | Permalink | TrackBacks (0)

As forecast, the cold system that passed over the American River Basin during the past day or so did not produce much in the way of liquid equivalent precipitation (a few tenths of an inch at best). The outlook for precipitation to occur in our domain during the next two weeks is not optimistic. There is a 500 mb cutoff low that wobbles around just offshore of central California during the latter part of next week, but it really doesn't produce much precipitation and barely makes it onshore before falling apart. The long range outlook based on tropical climate diagnostics provided by Ed Berry and Klaus Weikmann suggests that there might be better chances for active weather systems in our domain after week two.

There are no status issues to report today.

Kingsmill

Posted by Status Editor at 08:00 PM | Permalink | TrackBacks (0)

The current weather system is producing some radar echoes east of the Sierra crest, with snow reported in Reno and South Lake Tahoe. The Truckee 915 MHz profiler indicates low level flow out of the east-northeast, which is upslope on the east side of the Sierra crest. Over the American River Basin, there are only a few small, isolated echoes. The system is still forecast to produce no more than about a few tenths of an inch of liquid equivalent precipitation over the next 18-24 hours.

The medium to long-range outlook still does not provide much hope for precipitation in our domain out to at least 10 days. During our call on Friday, Klaus and Ed will lead a more extended long-range discussion.

Workstation status:

Installation of the ALPS workstation at Sacramento is in progress today, with training likely to start today or tomorrow.

Kingsmill

Posted by Status Editor at 07:48 PM | Permalink | TrackBacks (0)

A few light showers are currently evident in the vicinity of the American River Basin. Activity will probably increase slightly overnight into Thursday, but coverage will be spotty and total amounts of liquid equivalent precipitation will be well below 0.5 inches. In short, the decision yesterday not to declare an IOP for this system was the correct call.

Prospects for wet weather in our domain do not look good for the next week or two. The only glimmer of hope in the models is a strange cutoff low at 500 mb that is forecast to set up west of southern California / northern Mexico towards the middle of next week. This may turn out to be nothing or perhaps it is a signal of eventual undercutting westerlies from the subtropical jet. Time will tell. Klaus Weickmann and Ed Berry will provide a more extended discussion of the long range during our call on Friday (12 January).

No status issues to discuss at this time

Kingsmill

Posted by Status Editor at 08:31 PM | Permalink | TrackBacks (0)

A cold but weak storm will cross the HMT project area strating tomorrow evening and ending Thursday night. All of the models are predicting well less than 1 inch of liquid equivalent from this storm, which might end up being largely scattered snow flurries. This QPF is not impressive enough for an IOP. Therefore, we will settle for letting the unattended HMT instruments monitor this storm. Thus, no IOP and no crew deployments for now. Instead, we will save our resources for much bigger storms that may develop in the next several weeks.

However, the 10-day outlook continues to be predominantly dry. Currently, the next possibility for a storm appears to be late next week. Meanwhile, we will continue to monitor the forecasts on the daily conference calls.

- Martner

Posted by Status Editor at 07:49 PM | Permalink | TrackBacks (0)

Here is today's belated entry...

This may become a broken record for some time to come, but it is dry again in the American River Basin (ARB), and the system that is approaching on January 11th is unlikely to do much to alter this. It's inland track from the north, will bring cold air with little moisture. QPFs for the region at this time range from 1/4" to 1/2" with a fairly low snow levels on January 10-11. Whatever precipitation may fall, is likely to begin late on Wednesday, January 10th.

Thus at this time an IOP for this event seems highly unlikely. However, a final decision is not requred until Tuesday, January 9th. The chief scientist (Martner) and the lead forecaster (Szoke) will consult Tuesday morning, prior to the daily call, and issue early notification to the SMART-R and Sloughouse balloon crews, should it be necessary (i.e. if all of the models make an about face and bring some moist air to the ARB).

Long-term Outlook:
The ridge shows every sign of hanging on, blocking any real chance of wet weather in the ARB region. So out to 10-15 days at least, there is little likelihood of significant precipitation. But hey, it is the weather and it likes to fool us, so I'll keep watching...

Some Brief Administrative Notes:
Brooks Martner will be pinch-hitting for Tim Schneider as chief scientist on Tuesday, January 9th. Dave Kingsmill will begin his turn as chief scientist, one day early, on January 10th.

Schneider

Posted by Status Editor at 12:52 AM | Permalink | TrackBacks (0)

Little change since yesterday's update:

Dry in the ARB for the near-term. The models are in general agreement about a system impacting the ARB on ~ January 11th. However, at this time it is likely to be a cold system with little or no precipitation. One or two model outliers suggest other possibilities, but... we'll see tomorrow: same bat-time, same bat-channel.

Long-range prospects do not appear to be very promissing either, with the ridge indicating that it wants to anchor itself in place, blocking west coast systems. All this makes one wonder what we were all excited about last week. What happened with respect to the eastward propagating MJO would be an interesting topic for discussion. This is why HMT is here!

Schneider

Posted by Status Editor at 08:43 PM | Permalink | TrackBacks (0)

There remains no short-term weather to speak of. Since yesterday, there is little change in the thinking on the system that is approaching ~January 11th, save for the fact that there is a little less optimism for precipitation; at this time the models have the system too far inland and too cold for much precipitation.

So we will continue to monitor the weather in the Pacific with fingers crossed.

There are no other status issues to report at this time.

Schneider

Posted by Status Editor at 07:42 PM | Permalink | TrackBacks (0)

We have passed back into a quiet period in the ARB and continue to monitor events in the Pacific. While a pattern shift is in the works, there remains some confusion as to the timing and nature of the shift. At this time the next best option for an IOP appears to be about 10 days out (~15Jan). We'll continue to monitor the situation.

Instrument Status (good news):
ESRL-GSD shipped an ALPS system to the Sacramento WFO today. It should arrive on Monday, and a GSD team plans to be out there on Tuesday for installation and demonstration. The remaining systems will be distributed after a short demonstration period, as noted before.

Schneider

Posted by Status Editor at 10:28 PM | Permalink | TrackBacks (0)

IOP #3 is beginning to wane as the system begins to move out of the area. The last sounding at Sloughhouse occured at ~18Z. The SMART-R crew will hang on until the last showers exit the ARB - nominally 21Z, but at the discretion of Dave Jorgensen. Current radar and visible satellie imagery suggests some post-frontal triggering of small convective cells near Oroville and to the east.

While this IOP was not a levee buster, with generally 2.3"-2.5" of precip in the central ARB at this time, there were some interesting features regarding the evolution of this storm, especially concerning the wind shifts before and after FROPA and also regarding the early cessation of precipiation on the coast (related?).

Forecast:
At this time the forecast calls for a quiet period for several days. But the shifting patterns in the pacific may bring interesting weather later next week -- sometime on or after Jan 10th.

Schneider

Posted by Status Editor at 08:20 PM | Permalink | TrackBacks (0)

FROPA appears to have occured ~1700Z in the ARB.

Resource Status: 9 sondes were used for 7 soundings.

Here is an update from Foresthill (Jorgensen):
"Rain is finally winding down in the ARB. Just fairly weak stratiform remaining. Carroll and I will stay with it through at least the conference call. I've attached a screen dump showing the typical echo structure near the rain peak about 10 Z last night (2 AM PST). The vast majority of the rain was against the foothills and not much toward the valley. Peak reflectivities were only about 45, somewhat moderate in strength compared to the robust IOPs last year. Bright band seemed to come and go in strength as Brooks and Dave Kingsmill have noted from CALJET and PACJET studies of non-bright band rain."

"Radar has worked perfectly. No hiccups or data losses of any kind."

Schneider

Posted by Status Editor at 06:21 PM | Permalink | TrackBacks (0)

Dave Reynolds conference paper on the realtionship between the MJO and precip on the West Coast can be found at:

http://ams.confex.com/ams/pdfpapers/82840.pdf

If you have difficulty accessing this, send me an Email.

Schneider

Posted by Status Editor at 05:08 PM | Permalink | TrackBacks (0)

This is turning out to be a nice little event with precip at Blue Canyon already exceeding our expectations. Which raises an interesting question: why? Yesterday forecasts were generally calling for <2".

Some updated rain totals at this time (approx):

CFX: 0.6"
FHL: 2.6"
BLU: 2.5"
NDN: 1.8"
TRK: 0.5"

At Truckee (TRK) snow levels rose from 6800' at 4Z to 7800' at 0730Z. They have since dropped to 6700' again.

Here are a couple of overnight observations from Foresthill...

Dave Joregnesen:
"Its now 9700 UTC and the echo intensities have begun to drop off. A few hours earlier had fairly steady rain here and echo intensities approached 40 dbZ or so. ... No problems with the radar - been collecting data since startup at 0111 UTC."

Carroll Campbell (~15Z):
" It's just now getting light at the site, and the wind has just picked up and is blowing rain and shaking the trailer a bit."

Schneider

Posted by Status Editor at 03:47 PM | Permalink | TrackBacks (0)

The snow level (from profiler) at Truckee is being reported as 6800'.

Some rain totals at this time:
CFX: 0.2"
FHL: 0.6"
BLU: 0.7"
NDN: 0.3"
TRK: trace (<0.1")

Schneider

Posted by Status Editor at 05:55 AM | Permalink | TrackBacks (0)

Here is an update from Dave Jorgensen at Foresthill:

"I started data collection at 0111 with very light drizzle at the site started. Radar has worked continuously since then. Echoes are very light (max dbZ only about 30-35), but now covers most of ARB. Fog has also gotten fairly dense in the last hour or so. I would guess visibility is down to 50 yards or so."

Earlier (~22Z), Dave reported that the SR2 was operational with near-calm winds, sun to the SW but dark clouds to the north. Carroll Campbell has been "trained" and will work the graveyard shift.

Schneider

Posted by Status Editor at 03:42 AM | Permalink | TrackBacks (0)

IOP #3:
The forecast has been consistent over the past 3 days, with some slight variations in the timing and amount of precip in this system. The forecast calls for precip to begin at ~0Z January 3rd and end between 18-21Z on January 4th. FROPA is expected between 12-15Z on the 4th. Snow levels will begin at about 6500' to 7000' feet and drop to ~4000' after FROPA.

There is no cause to change the operating plan from yesterday:

> SMART-R operations are nominally slated to begin at 23Z on 3 Jan and to end at ~18Z on 4 Jan, however the SMART-R crew should be prepared for the IOP to continue at least until 21Z, and possibly longer

> Sloughhouse soundings will begin at 23Z on 3 Jan and will continue every three hours until 17Z on 4 Jan (total of 7 launches). The launch schedule is as follows (all times local):

1. Wed. 1/3, 3PM;
2. Wed. 1/3, 6PM;
3. Wed. 1/3, 9PM;
4. Thur. 1/4, 12AM;
5. Thur. 1/4, 3AM;
6. Thur. 1/4, 6AM;
7. Thur. 1/4, 9AM.

There will be no supplemental soundings at OAK and RNO.

As I post this belated entry, KDAX radar shows weak echoes (~20-25 dBZ) moving into the upper part of the ARB.

Long-term outlook:
As noted in the forecast discussion, there was a lively discussion about the 10-15 day prospects. A significant change in the current pattern is underway, with the MJO progressing eastward. This suggests that the west coast is in for an active stretch beginning on or about 11 Jan. Which part of the west coast would be affected is uncertain. Stay tuned and read John Brown’s nice summary of the discussion in the forecast blog.

Also, Andy Edman and Dave Reynolds were going to look into when NOAA's winter reconnaissance flights are to begin in the Pacific. It would be great if they could begin in time for the pending events.

Schneider

Posted by Status Editor at 12:07 AM | Permalink | TrackBacks (0)

IOP #3 has been declared and is set to commence on January 3rd.

Precipitation is expected to begin between 0Z-3Z, January 4th and to end between 18Z, Jan. 4th-0Z, Jan. 5th (local time: beginning at 4 pm-7 pm, January 3rd and ending between 10 am-4 pm on Jan. 4th). Blue Canyon could receive 1"-2" total, though there is some optimism for > 2". Snow levels should start at about 6500' and drop quickly to 4000' (or even 3500').

SMART-R Operations:
SMART-R operations are nominally scheduled to begin at 23Z January 3rd (3 pm local time) and to end at 18Z on January 4th (10 am local time). However, the SMART-R crew should be prepared to adjust start and end times somewhat, according to the initiation and cessation of precipitation - the goal being to bracket the precipitation with radar observations.

Sloughhouse Soundings:
A total of 7 sondes will be launched every three hours at Sloughhouse, beginning at 23Z (3pm local), January 3rd. The launch schedule is as follows (all times local): (i) Wed. 1/3, 3PM; (ii) Wed. 1/3, 6PM; (iii) Wed. 1/3, 9PM; (iv) Thur. 1/4, 12AM; (v) Thur. 1/4, 3AM; (vi) Thur. 1/4, 6AM; (vii) Thur. 1/4, 9AM.

There will be no supplemental soundings at Oakland or Reno for this IOP.

Instrument Status Update:
All surface data displays have returned to normal.

Also, due to an unfortunate event in at Oakland, the Oakland site is short staffed and launching supplemental balloons there may be problematic for some time.

Long-range:
Things might get interesting out beyond one week according to Dave Reynolds. See the forecast blog for further discussion.

Schneider

Posted by Status Editor at 08:26 PM | Permalink | TrackBacks (0)

It is dry once again in the American River Basin. Today's forecast assessment concurs with the past couple of days, though there is some cause for more optimism about getting 1"-2" of precipitation. This system is also expected to bring high winds at higher elevations and in the lee of the Sierras.

So we are still looking at an IOP (#3) for January 3rd-4th: Precipitation is expected to begin between 6Z (local: 10 pm, 3 Jan) and 12Z (local: 4 am, 4 Jan) on January 4th and end at about 0Z on the 5th (local: ~4 pm, 4 Jan), with peak precipitation occuring ~12-18Z on the 4th (local: 4 am-10 am). Snow levels will begin at 6500 feet and drop to 4000 feet by the end of the event.

Tentative plan for the soundings (Sloughhouse only): First sonde launch at 6Z January 4th. Last sonde launch 21Z on the 4th (after FROPA). Tomorrows call will firm everything up.

Long-range update from Klaus Weickmann:
Looking beyond the immediate future, Klaus's assessment of an event on the 10th and 11th is consistent with the current thinking of J. Brown and the west-coast forecasters: there is a slight chance of something on 10-11 Jan, but this looks like a dry system at this time. Things may begin to shake out and get more active beyond January 15th.

Instrument Status:
General status is nominal. A small glitch on the surface data display page (http://www.etl.noaa.gov/et7/data/) involving the date change (new year) is being looked into. The data are geing correctly displayed at: http://www.etl.noaa.gov/et7/data/sitemap/HMT/

Schneider

Posted by Status Editor at 09:01 PM | Permalink | TrackBacks (0)