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March 26, 2007

END OF HMT-West 2007

Active field operations for HMT-West 2007 have ended. Unattended sensors will continue to operate, although if they malfunction, they will not be repaired. The plan at present is to remove much of the remaining ESRL instrumentation during April and May. However, some surface sites, particularly those with soil moisture sensors, and the Truckee profiler, will remain in place long term.

Many thanks to the forecasters, engineers, instrument operators and coordinators, chief scientists, program managers and other key individuals that made HMT-West 2007 a success.

Dave Kingsmill

March 25, 2007

Project Status - 25 March 2007

Weather Status: Little change in outlook for precipitation for rain sampling. Rainfall event will start early Monday on the coast and lmid day in the mountains. Peak of event looks to be Monday evening ending by early Tuesday. Showers are possiibile in the cold core period Tuesday afternoon.

System Status: Coastal sampling from Sunday 2130 GMT to Tuesday 2130 GMT, and mountain sampling from Monday 0030GMT to Wed 0030GMT should capture all precipitation.

Operations Status: This is the last operational blog. Thanks to the stalwart few who held on to the end.

John McGinley, GSD

March 24, 2007

Project Status - 24 Mar 2007

Weather Status: Only issue today is when to turn on the rainfall samplers. IPW band still moving down coast but at a slower rate. Precip band moving with front should move into the area Sunday afternoon on the coast and later in the ARB. Cazadero and Bodega Bay look to be about 8 hrs ahead of Alta. Trough should bring moderate amounts of rain to the area.

System Status: Plan is to start the 48-hour collection period at 2130GMT at the coastal stations and 0030GMT Monday at Alta.

John McGinley, GSD

March 23, 2007

Project Status - 23 Mar 2007 - update

Owing to receiver problems at Slough House no soundings will be possible, so all sonde activities will be terminated for this IOP. The IOP will go on for modeling and precipitation collection so there will be a call tomorrow at 1830 GMT. Thanks to the efforts of all the folks at Reno and Slough House for their sonde
support over the HMT exercise.

McGinley

Project Status - 23 Mar 2007

Weather Status: Storm on track for a combination of events: First, an IPW plume is moving down the coast. Observational evidence shows this to be a well defined feature. Models bringing this into the ARB region after 18GMT Sunday, yet forecast no precipitation of any consequence. Second, trough and front with an intense period of warm advection rain begins Monday. Third, cold frontal passage looks to be late Monday/early Tuesday. Total precip amounts look to be in the 2-3 inch category with well defined warm advection precipitation. Thus we are calling an IOP for this event begining at 16GMT Sunday with sonde releases an hour earlier at both Slough House and Reno, and then continuing every four hours. By starting sondes early we can document the establishment of the moist plume, moistening of the PBL, and try to determine if the plume is actually stronger than predicted, and assess why models are not creating any rain in the warm advection on Sunday. Sonde schedules will be adjusted as necesssary at tomorrow's call.

System Status: for planning, sondes at Reno and Slough House centered on Sunday 16, 20; Monday 00, 04, 08 12 16 20; Tuesday 00, 04, 08GMT. Local time releases at Sunday 8am, 12pm, 4pm, 8pm; Monday 12am, 4am, 8am, 12pm 4pm, 8pm; Tuesday 12am....last one.

Rainfall sampling will be done during this event.

John McGinley, GSD

March 22, 2007

Project Status - 22 Mar 2007

Weather Status: Storm for Mon-Tues looking stronger in latest model runs. Precip amounts for the ARB are in the 1-3 inch range. Models indicate significant precipitation commencing early Monday with most intense period Monday evening. Moisture plume now pointed at the Pacific NW will drop south with the approach of the trof and be aimed at the ARB as early as Sunday afternoon. Models are indicating showers begining at this time. So....there are improved prospects for an IOP . One observation strategy would be to document the moistening of the boundary layer with time as the IPW plume and troph merge. This suggests sondes as early as Sunday. A decision on this will be made on Friday. So to summarize: possible IOP Mon-Tues with an outside chance of a Sunday start.

System Status: Sonde inventory shows numbers enough to cover this potential 48-hour event.

Operations Status: With the call today the HMT Experimental Period is formally over, however telecons to discuss this next potential IOP will continue daily at 1830GMT for those interested. The Status and Forecast blogs will also continue through the coming event. Operations are likely to shut down late Tuesday. Thanks to all who participated in the daily calls and the readers of the blogs.

John McGinley, GSD

March 21, 2007

Project Status - 21 Mar 2007

Weather Status: To wrap up the weak event yesterday, the trough did produce some scattered afternoon showers and thunderstorms that produced some moderate precipitation in the Central Valley. Blue Canyon had a few hundredths out of an afternoon shower. Focus for today is a system due to impact the ARB on Mon-Tues (Mar 26-27). If systems maintains its forecast strength HMT will be extended to capture the event. Flow by the weekend is predicted to be more zonal with a weak but well defined moisture plume and good wind speeds at 700mb. Most precipitation by the GFS appears to be frontal. The storm will have abundant cold air so snow levels may be low for March. Liquid amounts look like 1-2 inches, but this appears to be a downward trend relative to earlier progs. Timing is pretty consistent within the GFS ensemble, but the ECMWF is slower by 24 hrs. Timing on event looks like first raindrops at 18GMT on Mon (Mar 26) and ending Tues at 12GMT. So another brief event. Storm is still a monitoring target so we'll update the prospects tomorrow.

System Status: ALPS timing tests were completed for the RFC and RNO, still some problems with SAC. MRY will be done tomorrow.

John McGinley, GSD

March 20, 2007

Project Status - 20 Mar 2007

Weather Status: Storm over ARB almost a complete bust as wave basically split with energy going north and south of the experimental area. As of 20GMT Blue Canyon had no observed precipitation, despite the fact that the NAM last night was going for near an inch. Model ensembles never quit forecasting precipitation as well with amounts up to 1.5 inches even as late as the 20/06GMT runs. This mornings runs hinting at shower activity this afternoon beneath the cold core. NWS also expecting showers, so there may not be a complete shutout as the afternoon progresses. Case will be saved to study a bust situation. Beyond the end of the exercise the storm for next Mon-Tues (26-27 March) looks to be on an upward trend in the GFS and other global models. So outlook is for a possible event Monday-Tuesday. This will extend the exercise 4-5 days for ESRL staff.

System Status: Lack of rain at Slough House precluded the receiver test. All models up and running but not forecasting well.

Operations beyond 22 March: Telecons will be conducted with only ESRL personnel. Chief Scientist Fri-Tuesday: McGinley; Forecaster Fri-Sun: Szoke; Forecaster Mon-Tue: Schultz. Call participants will be all ESRL HMT staff: Kingsmill, Martner, Schneider, Neiman, White, Splitt, as available.

John McGinley, GSD

March 19, 2007

Project Status - 19 Mar 2007

Weather Status: Storm approaching coast is on schedule for a Tuesday morning arrival in the ARB, however precipitation amounts are marginal at best. Models keeping precip in the ARB in the .5-0.75 range over a very short duration (12-15 hrs), so not calling an IOP still looks like a good decision at this time. Ensemble models showing a bit more precip than large scale models with amounts up to 2 inches 100km NW of the ARB. In the ARB amounts are below an inch. NWS is in agreement with 0.5-0.75 forecast for the ARB. Further out, a very strong jet in the mid Pacific coupled to increasing convection in the area near 140E will begin to change things in the eastern Pacific. Long range models and MJO/Rossby wave propagation diagnostics indicate troughy conditions developing over the coast over the next two weeks. This, of course is beyond the sheduled end of the HMT. Consensus was that two storms (26-27 and 29-30 March) should be monitored for possible data collection. So...no IOP on current wave. Extension of project into next week is possible.

System Status: All local models back in action so a workstation comms timing test will be scheduled for Tuesday.

Operations Proposal: Daily telecons will end on the 22nd. ESRL personnel (only) will have a daily local consultation 23 through 30 March to determine if soundings should be launched for the two storms likely in the next week (26-27 March and 29-30 March). NWS and Slough House will be notified 24-48 hrs in advance for supplemental sondes. NWS will be consulted on forecast details as needed. ESRL personnel will will serve as volunteer forecasters through the extension period. Please give this proposal some condideration. We will discuss it on Thursday.

John McGinley, GSD

March 18, 2007

Project Status - 18 Mar 2007

Weather Status: Today's model runs continue to downtrend the QPF in the HMT region. Most models are well under an inch for the 16 hour event. Precip should begin 20 March 06-09GMT and be over by 22 GMT. It doesn't look like this will meet IOP criteria of 1inch in 24 hrs. NWS in agreement with low precip totals. Moisture band ahead of trough is weaker today than yesterday. All in all a discouraging outlook for the last storm in the regular HMT experimental period. Outlook beyond the 22nd indicates a possible stormy period next weekend, but details haven't revealed themselves as yet. During Monday's discussion we will consider extending the experiment to capture the weekend activity. If there is a big turnaround in the next 24 hrs we could consider a late-hour IOP, but right now this looks unlikely. So bottom line: no IOP for Tuesday.

System Status: Slough House may take advantage of rain Tuesday morning to test rawinsonde receiver. WRF-NMM still down. Other ensemble members running.

John McGinley, GSD

March 17, 2007

Project Status - 17 Mar 2007

Weather Status: System expected early in the week continues to be a tough call. Models today are uniformly slower with the system not initiating precipitation until Tuesday morning. The length of the event is 24 hrs at best. Precip totals look to be near an inch but consensus looks more like 0.5 to 0.75. A slower scenario could be good as this enhances the entrainment of a weak moisture plume. Best guess at timing is first raindrops about 09GMT 20 Mar (Tue 2am) with the event over 06GMT 21 March (11pm Tuesday). Beyond this current system it looks like the Pacific is energizing with strong jet flow establishing itself off the Asian coast. Long range models show a possible system next weekend. with more after that. A decision for extending the project will be made on Monday after our interactions with the long rangers, Ed and Klaus. So for today, a possible IOP begining Tuesday, with a final go/no-go decsion tomorrow.

System Status: As a heads-up, if soundings are necessary for a Tuesday IOP , best guess is for launches near midnight to 1am Tuesday morning. Sonde frequency and more precise timing will be decided on tomorrow, IF an IOP is called. IOP or not, Slough House, under rainy skies should take the opportunity to perform a receiver test.
Local ensemble is running but not long range WRF-NMM, still down owing to data transfer problems.

John McGinley, GSD

March 16, 2007

Project Status - 16 Mar 2007

Weather Status: All signs are pointing to an open wave impacting central CA by Monday mid-day. Strength of system is still an issue with models backing off a bit on total precipitation. An IPW plume is present and may be captured by the wave. If so this could increase rainfall substantially. Current model forecasts indicate 0.8 to 1.3 inches with the higher amounts north of the HMT area. NWS feels QPF from 0.5-0.8". Precipitation start time in HMT domain would be 18GMT Monday. Precipitation could go on into Tuesday afternoon/evening. HPC not as encouraging with amounts less than half-an-inch. We'll look at this Saturday to better determine the prospects for an IOP. Monday we will look at the long range to consider prospects beyond the HMT end date of 22 March. So for today, looking 72hrs out, we may be launching an IOP. Over the weekend we'll fine tune this outlook.

System Status: Slough House has 18-19 sondes, enough for 3 days or so. Sonde activities need 24-48 hrs notification so will update Saturday and Sunday for possible Monday operations. Model data from WRF-ARW ensemble is streaming again. Problems still with NMM. Workstation timing test will not go forward until full model complement is up and running.

John McGinley, GSD

March 15, 2007

Project Status - 15 Mar 2007

Weather Status: Wave in mid Pacific will be focus of activity expected on Mon-Tues (Mar 19-20) next week. GFS a bit more encouraging today with larger QPF values offering the potential for over an inch in 24 hrs. System still is moving pretty fast making a 24 hr event likely. General trend in the GFS is for a stronger wave and wetter conditions all pointing to a likely operation Monday and Tuesday. Best guess on time would be 19/2100GMT to 20/2100GMT. NWS is on board with this outlook and is including precipitation in the long range forecasts. Beyond this event it appears that the subtropical jet is stronger suggesting that the models are "feeling" the tropical precipitation. Much more activity is evident for the latter part of next week. We will try to make a decision on Monday for extending the HMT beyond Mar 22nd for an impending intense event. For the next 72hrs no activity is expected.

System Status: A workstation comms test is needed requiring that high res model data be available. A fire over the weekend took out a Myrinet switch and this has deactivated 64 nodes on Jet. This has slowed down jobs to the point where output processing is quitting owing to time limit defaults. Thus model data has not been written to storage areas and ported to the ALPS disk. Chris Anderson is looking into this and possible work arounds.

John McGinley GSD

March 14, 2007

Project Status - 14 Mar 2007

Weather Status: Dry and warm as ridge builds over the HMT region. Trof of interest is in mid-Pacific. GFS deterministic run is fastest and driest of all models as the open wave hits the coast on Mon-Tues (Mar 19-20) next week. European, NOGAPS and Canadian all agree on a stronger, slower moving wave more in the Tue-Wed time frame. With the convective flare-up at 140E, models are probably slow to have worked in the latent heat release and momentum transfer so models may be unreliable and variable for a few cycles. Best guess is to favor the slower consensus and stick with a Tuesday-Wednesday scenario. Long range outlook for week two is uncertain for the same reason. Tropical flare-up will have impact on momentum transfer into mid latitudes and strenthening of subtropical jet. This points to possibly more favorable conditions beyond the event next week. We will update the long range outlook Monday to determine if project will continue beyond 22 March. For today: No IOP for the next 72 hours.

System Status: High resolution models went down owing to loss of nodes. Runs are needed for ALPS workstation timing tests.

John McGinley, GSD

March 13, 2007

Project Status - 13 Mar 2007

Weather Status: As expected ridge has flattened today, but no weather is in the HMT area. Ridge will build for the next few days with warm tempertures expected over central CA. System moving off the coast of Asia today, will be the one to watch for next week. GFS solutions not as consistent as the set yesterday with the 12GMT run favoring a two-trough scenario, a minor one Tuesday and a higher amplitude system on Wed. GFS ensembles more consistent with single wave scenario, as are other models. Many of these sugest a slower evolution, more like Wed-Thursday (21-22 March). Good news is that models are holding out the hope of an IOP for mid week. For the next 72 hours, however, no weather or IOP is expected.

System Status: No reports.

John McGinley, GSD

Project Status - 12 Mar 2007

Weather Status: Ridge is flattening somewhat as as series of shortwaves impacts the Oregon-Washington coasts. Even the weak waves are getting weaker as the upper trof expected in the area later this week looks more insignificant. Good model consensus still points to 20-21 March with a major trough in the offing. Models, both deterministic GFS and ensembles have eliminated the closed off solution, brining in an open wave. UH IPW forecast shows a weak river in association. Long range outlook is planned on Wed to get some information to determine if the HMT goes beyond the 22 March closing day or is ended early. No IOP expected for next 72 hrs.

System Status: Turns out yesterday the HMT web page was down, even though the blog editors were up and running. All is good today.

John McGinley

March 11, 2007

Project Status - 11 March 2007

Weather Status: Outlook still bleak for the short term (0-5 days). A closed low will drift toward the coast by 15-16 March but models are indicating dry conditions with it. We will continue to monitor this system. Some flattening of the ridge off the coast is occurring but not enough to bring systems into central California. Beyond 5 days ridge grows, sustaining dry conditions. First break may come in the March 20-21 time frame. Question here is whether trof comes in as an open feature or closed-off. 9-10 days is a long way off and much could change. Decision for today: no operations for 72 hours.

System Status: All ESRL systems appear to be up and running today.

John McGinley

Project Status - 10 March 2007

Weather Status: General ridging conditions over the eastern Pacific with moist flow aimed at Oregon and Washington coasts. Ridge should flatten somewhat today and tomorrow with weak short waves moving moisture southward but not into the HMT area. Beyond 48 hours ridge builds off the coast moving the storm track further north and maintaining dry conditions over central California. Long range progs indicate the first chance for a significant trough is in the March 20-21 time frame. So for today......no operations anticipated for the next 72 hours.

System Status: A scheduled power outage at ESRL put most systems on reserve power with no impact to the models. HMT server was out most of Saturday. This delayed posting of forecasts and status on the blogs.

John McGinley

March 09, 2007

Project Status - 9 March 2007

Weather Status: Weak system will bring some light showers to areas of northern California, but no significant precipitation is expected. In the HMT area itself only a few elevated showers my be roaming around with no accumulation of rain. Out look for the next few days is to see some flattening of the ridge which will bring some significant moisture to the Oregon and Washington coasts, but nothing in central California. After that further building of the ridge will elimate any possibility of an IOP for a week or more. Beyond that a pattern change may be in the offing as discussed by our long range forecasters earlier this week. Bottom line: no IOP for the next three days.

System Status: No reports.

John McGinley

March 08, 2007

Project Status: 8 March 2007 (Thursday)

The past 24 hours delivered a bit of rain to the American River Basin, but things are looking dry in the coming days. We'll keep monitoring things and hoping that the Pacific can conjur up a system that will rain on the ARB next week (though I am mindful of the old adage, be careful of what you ask for...)

John McGinley will lead tomorrow's call.

T Schneider

March 07, 2007

Project Status: 7 March 2007 (Wednesday)

Light rain (<= 1/4") is expected in the American River Basin today, then drying. No IOPs today or in the next few days. Next chance is ~ one week out, stay tuned. Today's long-range discussion suggests a more active period is possible in weeks 2-3. We'll revisit this again in one week.

No Status issues to report at this time.

T. Schneider

March 06, 2007

Project Status: 6 March 2007 (Tuesday)

Little change in the outlook: light precipitation on Wednesday embedded in a sea of dryness. No IOPs on the horizon at this time. Let's hope that our long-range discussion with Ed Berry and Klaus Weickmann tomorrow (Wednesday, 7Mar), gives us a little hope.

Status Issues:
+ Two new snow depth sensors have been installed at Big Bend (BBD) and Truckee (TRK).
+ The heated tipping bucket at Blue Canyon (BLU) has been fixed.
+ a planned power outage in Boulder CO on Saturday (10 Mar) will temporarily disable the HMT data server.

T. Schneider

March 05, 2007

Project Status: 5 March 2007 (Monday)

The outlook in a few words: not too exciting. Dry conditions in the American River Basin into Wednesday, then a weak system brings light precip Wednesday into Wednesday night -- less than 1/2" is expected. No IOPs are planned at this time.

Instrument Status:
A number of tests have been run on the sounding system at Sloughhouse. As a result the antenna for the sondes has been anchored a little better. We'll try to run a test during the light rain on Wednesday to see if we have worked out any of the kinks.

T. Schneider

March 04, 2007

Project Status: 4 March 2007 (Sunday)

Nothing to fret over for the next couple of days. Looking to mid-week, a warm but weak system is expected to affect the American River Basin on Wednesday with light QPFs. CNRFC is not overly concerned at this time with any rain-on-snow scenarios. On the whole, this system appears to be marginal at best.

We can defer any decisions about a possible IOP (which would be #8) until Monday or perhaps even Tuesday, but given today's outlook I would like to see things improve a bit before I get optimistic about an IOP. Factors influencing our decision: There was some discussion on today's call about things drying out in the ARB through mid-March which favors a more aggressive strategy. Also, as discussed in yesterday's status blog, is the situation with the Sloughhouse soundings, which have been problematic and are being debugged. This favors conserving resources. Finally, Reno would like at least a days notice for supplemental soundings, which gives us a little time should the QPFs begin to bump up in later model runs.

T. Schneider

March 03, 2007

Project Status: 3 March 2007 (Saturday)

The American River Basin is in for a pleasant day today with clouds building tomorrow then clearing through Monday.

The next shot at an event is Tuesday evening (00Z Wednesday), but at this time the models have it weakening. There is one interesting aspect to this event in that it will be a warm system and there is still a considerable amount of snow at lower elevations.

Decisions concerning a possible IOP#8 on Tuesday into Wednesday will depend on the forecast (at present it is marginal so d(model)/dt is important) and the status of the sounding system at Sloughhouse (see below).

Instrument Status:
We're still debugging the Sloughhouse sounding data system which has been acting up. We might be able to borrow a spare data system from within PSD but this is pending some additional tests. Timing is a factor (will we have enough time to get the borrowed system out there for the next IOP?)...

The SMART-R should be well on its way to OK by now (if it is not already there). So no more special radar operations for this year.

T. Schneider

March 02, 2007

Project Status: 2 March 2007 (Friday)

Over the last 24 hours, there have been a few stray showers in the American River Basin, but that activity is pretty much gone now. Our attention continues to focus on a potential wet and warm storm forecast to hit the west coast toward the middle of next week. Guidance from the last couple of forecast cycles indicates that the event is likely to be mostly north of our domain. There are also signs that the forecast intensity of the system is decreasing. It's still a long way out, so a lot can change.

Instrument status issue:

1) The 915 MHz wind profiler at Sloughhouse is back online.

2) The tipping bucket precipitation gauge at Blue Canyon is recording an accumulation this afternoon. This is an artifact. With air temperatures rising above 0 C at the site for the first time in a while, the snow that had collected in the unheated bucket (heater failure) is finally melting and creating tips.


Kingsmill

March 01, 2007

Project Status: 1 March 2007 (Thursday)

Some isolated showers still remain over the American River Basin. Only about 0.1 to 0.2 inches of liquid has fallen since the end of IOP-7 yesterday afternoon at 00 UTC. The showers will shut down later tonight as a ridge builds in to the area for the next couple days. Our next chance of significant precipitation appears to be early next week. A wet and warm storm is forecast to hit the west coast late Monday into Tuesday. This scenario could pose serious hydrologic concerns given all of the snow that has recently fallen, especially the snow at mid-slope levels (3000-5000 feet). The question is exactly where the storm will hit along the coast. Over the last few forecast cycles, model guidance has been pushing the brunt of the storm into extreme northern California and southern Oregon. Given the potential significance of the storm, attempts will be made to engage the Winter Storms Recon program to perform targeted observations in the Pacific that will provide better initialization information for the models

On the coordination call tomorrow (Friday), we will have an extended discussion about IOP-7. A summary of IOP-7 has been posted to the Operation Summary blog.


Kingsmill