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Texas/MX Obs And Discussion Thread.


Srain

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Per the operational Euro, Ed, yes. However, the CMC ensembles had almost half of its members showing that trough further west and much colder for the Southern Plains.

Operational runs continue to struggle with the pattern per HPC.

The 12Z GEM continues to suggest a better PNA ridge. We will see...:scooter:

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I posted the Raleigh Euro ensemble means to show that the ensembles gave pretty good support to the operational Euro. Maybe I should re-read B-I's piece on proper use of models, and not hugging the Euro over other models, but if the Op Euro is supported by the means, it could be wildly wrong, but I trust it over the Canadian.

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So much for that warming trend expect starting tomorrow. HGX has lowered high temps for tomorrow yet again. We seem to be in a 15-20 degrees below climo pattern since last Sunday. Next week continues to look mighty interesting as well.

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Looking wet across the Lone Star State this weekend...

I won't say no to the rain, but we remain in the stable sector looking at the NAM, and are far enough removed from the cold air not to have any p-type fun. 500 mb low almost overhead, I was hoping maybe a pocket of happy thickness for Monterrey, but apparently not.

Maybe the GFS will be happier.

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I won't say no to the rain, but we remain in the stable sector looking at the NAM, and are far enough removed from the cold air not to have any p-type fun. 500 mb low almost overhead, I was hoping maybe a pocket of happy thickness for Monterrey, but apparently not.

Maybe the GFS will be happier.

No source of cold air for that one, and it's too weak of a shortwave to "create it's own cold". When a big cold high is missing, you need sub 558dm lows..and even then you might have boundary layer issues. I got one of those like 10 years ago, no cold air and sleet with surface temps around 50F

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HPC says toss out the GFS and Canadian as too progressive (fast) and trust the Euro (and UKMET to some extent)...regarding the pattern and pressures…support for a cutoff low to our W gains momentum...

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

155 AM EST FRI JAN 14 2011

VALID 12Z TUE JAN 18 2011 - 12Z FRI JAN 21 2011

THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7 ARE

BASED ON THE 00Z/14 ECMWF. THE LATEST DETERMINISTIC ECMWF HAS

ROBUST SUPPORT FROM BOTH THE 12Z/13 ECENS MEAN AND THE 00Z/14

UKMET FROM COAST TO COAST FOR MUCH OF THE MEDIUM RANGE. THE GFS

AND GEM GLOBAL ARE OUT OF SYNC WITH THE STRONG EUROPEAN CENTRE

CLUSTER WITH THE HANDLING OF THE MAJOR SHORTWAVES AFFECTING THE

NATION THIS FORECAST PERIOD...WITH THE GFS NOT EVEN WELL

CORRELATED WITH THE 00Z/14 GEFS MEAN. THE ECMWF HAS BEEN

VERIFYING STRONGLY ON AVERAGE THIS COLD SEASON WITH ITS SURFACE

PRESSURES...PARTICULARLY DAYS 6 AND 7. THE UPCOMING PATTERN WILL

BE HIGHLIGHTED BY SOME OF THE COLDEST AIR OF THE SEASON THUS FAR

FOR PORTIONS OF THE GREAT LAKES AND NORTHEAST...WITH LOW

THICKNESSES COINCIDING WITH HIGH SURFACE PRESSURES.

CISCO

San Angelo concurs and mentions the flip of the 06Z GFS...

HE MAIN ITEMS OF FOCUS NEXT WEEK POSSIBILITY OF FAIRLY STRONG

COLD FRONTAL PASSAGES LATE MONDAY NIGHT AND AGAIN THURSDAY MORNING.

A GOOD WARMUP IS EXPECTED ON MONDAY WITH WEST-SOUTHWEST LOW-LEVEL

FLOW AND 850 MB TEMPERATURES CLIMBING ABOVE 10 DEGREES C. AFTER

THE COLD FRONTAL PASSAGE HIGHS ON TUESDAY SHOULD BE AROUND 12-16

DEGREES COOLER THAN MONDAY. THE 00Z GFS AND ECMWF CONTINUE SO HAVE

DIFFERENCES WITH THE PATTERN LATER NEXT WEEK. THE 06Z GFS NOW

DEVELOPS AN UPPER LOW SOUTHWEST OF CALIFORNIA ON THURSDAY...WHICH

IT DID NOT SHOW ON ITS 00Z RUN. THE 06Z GFS LOOKS MORE SIMILAR TO

THE 00Z ECMWF WITH THIS FEATURE. GFS IS ALSO FASTER AND NOT AS

STRONG WITH THE COLD FRONT...BRINGING IT THROUGH OUR AREA EARLY

THURSDAY MORNING. THE ECMWF HAS THE FRONTAL PASSAGE DURING THE DAY

THURSDAY...HAS STRONGER COLD AIR ADVECTION AND IS SLOWER WITH THE

MODIFICATION ON FRIDAY. MODELS HAVE NOT BEEN SHOWING VERY MUCH

SKILL ON DAYS 6 AND 7. AT THIS TIME...LEANING TOWARD THE ECMWF

SOLUTION WHICH IS FAVORED BY HPC.

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I'll throw in my quick 2 cents before starting on the forecast for today. A quick glance at the 00z ECMWF and 06z GFS makes me want to puke. I strongly favor the overall pattern of the ECMWF by midweek (maybe not as wet) but I don't see why we won't see another quick blast of cold air by Thursday. Currently, western Canada has temps of -30F to -40F with surface pressures as highs as 1052 mb. We are seeing a good cross polar flow setting up through the weekend which should help to reinforce/intensify the cold temps. Sure, this cold air could be shunted to our east but I'm thinking we'll get at least a 1 day shot. Stay tuned... :whistle:

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I'll throw in my quick 2 cents before starting on the forecast for today. A quick glance at the 00z ECMWF and 06z GFS makes me want to puke. I strongly favor the overall pattern of the ECMWF by midweek (maybe not as wet) but I don't see why we won't see another quick blast of cold air by Thursday. Currently, western Canada has temps of -30F to -40F with surface pressures as highs as 1052 mb. We are seeing a good cross polar flow setting up through the weekend which should help to reinforce/intensify the cold temps. Sure, this cold air could be shunted to our east but I'm thinking we'll get at least a 1 day shot. Stay tuned... :whistle:

Good luck on that forecast, wall_cloud. I see the GFS has flipped again...:arrowhead:

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it sure has. Luckily, it has come in line with what I had thought yesterday with the cold air coming in very early Thursday.

Now the GEM agrees on a Thrusday FROPA. Oh and now we have another model suggesting a cutoff...

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The 12Z Euro now suggests the Arctic front will enter the Panhandle on Tuesday evening. And look out to our W. That model now suggests the cutoff low will move in a bit faster and cold air is becoming established across the Lone Star State...

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:popcorn:

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

215 PM EST FRI JAN 14 2011

VALID 12Z MON JAN 17 2011 - 12Z FRI JAN 21 2011

...MODELS AND ENSEMBLES SHOW QUITE AN INTERESTING FLOW PATTERN

OVER NOAM OVER THE NEXT WEEK...

GUIDANCE IN A LARGER SENSE AGREES THAT A COOLING/UNSETTLING AND

AMPLIFIED MID-UPPER LEVEL TROUGH WILL STEADILY PROGRESS FROM THE

EAST-CENTRAL US TO WRN ATLANTIC TUE-THU. IN THIS FLOW EMBEDDED

SYSTEM AND STREAM PHASING ISSUES THOUGH INTRODUCE INCREASED

UNCERTAINTY THOUGH AT LOWER LEVELS...ESPECIALLY WITH LOW

DEVELOPMENTS AND SENSIBLE WEATHER FOCUS. SOME OF THIS UNCERTAINTY

SEEMS RELATED TO THE LOW LEVEL RESPONSE TO HOW POTENT LEAD

ENERGIES DIGGING OUT FROM THE WRN US INTO THE BASE OF THE

MID-UPPER LEVEL TROUGH VERIFIES ACROSS THE US SRN TIER INTO EARLY

NEXT WEEK. THE 00 UTC ECMWF/UKMET/ECMWF ENSEMBLE MEAN ARE

SIGNIFICANTLY MORE AMPLIFIED THAN THE 00 UTC GFS/CANADIAN AND

THEIR RESPECTIVE ENSEMBLE MEANS. A SOLUTION ALOFT ON THE MORE

AMPLIFIED PORTION OF THE FULL SOLUTION ENVELOPE PROVIDED BY

GUIDANCE SEEMS REASONABLE CONSIDERING LATEST WATER VAPOR IMAGERY.

AT LOWER LEVELS THE 06 UTC GFS DID SUPPORT A MORE DEFINED SURFACE

WAVE AND THE 12 UTC GFS HAS NOW TRENDED TOWARD A MORE AMPLIFIED

SYSTEM. HPC PROGS MAINTAIN REASONABLE CONTINUITY WITH A LOW

TRACK/CYCLOGENESIS OVER/OFF THE MID-ATLANTIC THEN NEW ENG

TUE/WED...ALBEIT WITH LINGERING UNCERTAINTY CONSIDERING RECENT

GUIDANCE SENSITIVITY INCLUDING THE 12 UTC ECMWF THAT IS NOW

SLIGHTLY LESS AMPLIFIED/DEVELOPED THIS SYSTEM.

UPSTREAM...THE 00/12 UTC ECMWF/UKMET OFFER A STRONGER SOLUTION

THAN THE 00/06/12 UTC GFS AND CANADIAN WITH RE-EMERGING NRN STREAM

TROUGH ENERGY ALOFT SLATED TO DIG INTO THE NORTH-CENTRAL US

MIDWEEK AND ACROSS THE EAST-CENTRAL NRN TIER OF THE US INTO

THU/FRI THAT WOULD FAVOR QUITE AN ASSOCIATED LOW-LEVEL SURGE OF

BITTER COLD AIR INTO MUCH OF THE EAST-CENTRAL US AT THAT TIME.

ALSO...THE 00 UTC ECMWF/UKMET AND TO A LESSER EXTENT THE 00 UTC

ECMWF ENSEMBLE MEAN MEANWHILE DEPCIT MUCH SHARPER DIGGING OF

TROUGH ENERGIES FARTHER BACK DOWN THROUGH THE US WEST COAST. THIS

LEADS TO CLOSED LOW DEVELOPMENT CENTERED IN THE VICINITY OF SRN CA

BY DAYS 5-7 WED-FRI COMPARED TO MUCH BROADER AND MORE PROGRESSIVE

MID-UPPER LEVEL TROUGH PASSAGE ACROSS THE W-CENTRAL STATES IN

RECENT GFS/CANADIAN MODEL AND ENSEMBLE RUNS. THE 12 UTC GFS

THOUGH HAS TRENDED SLIGHTLY MORE AMPLIFIED THAN PRIOR 00/06 UTC

RUNS BUT THE 12 UTC ECMWF/UKMET HAVE TRENDED MORE PROGRESSIVE THAN

THEIR PRIOR RUNS...SEEMINGLY ALL WORKING SOMEWHAT CLOSER TO A MORE

CONCENSUS SOLUTION AT THIS POINT.

AS PER THESE TWO GUIDANCE DIFFERENCES HIGHLIGHTED JUST ABOVE...A

DEEPLY AMPLIFIED LOW/TROUGH ANCHORING ACROSS THE NORTH PACIFIC

NEXT WEEK DOES HAVE QUITE A BIT OF JET ENERGY RUNNING UNDERNEATH

TO VARIOUS DEGREES. THIS NONETHELESS SEEMS MORE LIKELY TO FAVOR

MAINTAINING FOR A LONGER PERIOD A GREATER DOWNSTREAM RIDGE

AMPLITUDE ON THE HIGHER SPECTRUM OF THE FULL ENVELOPE OF SOLUTIONS

ACROSS THE NERN PACIFIC. THIS SHOULD THEN LEAD TO AN INCREASED

OPPORTUNITY FOR AT LEAST REASONABLY VIGOROUS DOWNSTREAM

DIGGING/AMPLITUDE WITH BOTH THE WRN US AND N-CENTRAL US SYSTEMS

MID-LATE NEXT WEEK. CONSIDERING THIS...BUT WITH STILL AMPLE

FORECAST SPREAD WITHIN ALL GUIDANCE...THE PRELIM HPC SOLUTION WAS

PRIMARILY DERIVED FROM A NEAR EVEN BLEND OF THE QUITE AMPLIFIED 00

UTC ECMWF AND A SOMEWHAT LESS ROBUST 00 UTC ECMWF ENSEMBLE MEAN.

FINAL HPC GUIDANCE MAINTAINED CONTINUITY STRENGTH OVER THE

N-CENTRAL US...BUT DID TREND TOWARD A SOMEWHAT MORE PROGRESSIVE

CA/SW US SYSTEM AFTER CONSIDERATION OF LATEST 12 UTC MODEL AND

ENSEMBLE GUDIANCE.

SCHICHTEL

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Wintry weather looks likely with the Jan 21st-22nd impulse for somewhere in TX. Too early to tell where, but W and N TX are the common sense suspects. Another round of negative NAO is very much in play for late Jan. No warmup on sight, other than the C and N W Coast.

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Wintry weather looks likely with the Jan 21st-22nd impulse for somewhere in TX. Too early to tell where, but W and N TX are the common sense suspects. Another round of negative NAO is very much in play for late Jan. No warmup on sight, other than the C and N W Coast.

Yep. Looks like a classic ice event at this range from W Central/Central/N and NE TX. Depending on just how strong the frontal boundary is and how far S it pushes mid week, perhaps part of S Central/SE TX could be added to that mix. We will see. I saw the NAO trend. Also nice to see the AO backing off that flirt with a positive. PNA is looking yummy...:wub:

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Sure looks like a classic Lone Star State Ice Storm in the making at this stage of the game. The trends today suggest the Arctic boundary will be pushing S into the Panhandle late on Wednesday. With the trough axis to our W and any U/A disturbance lurking in the NW flow, a classic over running event could well happen. Got to love those sharp/shallow Arctic Boundaries.

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Nice dent in the drought if it verifies...

Dent me, please... I'll pass on the ice if possible though :P

We've barely broken 40 degrees all week; that's not excruciating, but it's at least 10-15 degrees lower than was forecast for this weekend, plus we've had more moisture than anticipated for this last couple of weeks. Knowing that, I'd hedge my bets towards the colder/wetter side for next week as well...

Thank goodness I just had a woodheater installed - we'll be toasty warm even if we freeze over! :sun:

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HPC says all the operational models are out to lunch...:guitar:

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

722 AM EST SUN JAN 16 2011

VALID 12Z THU JAN 20 2011 - 12Z SUN JAN 23 2011

VERY POOR MODEL AND RUN TO RUN AGREEMENT THIS FORECAST PERIOD. ALL

OPERATIONAL MODEL FORECASTS ARE SUSPECT. USE OF LAGGED AVERAGE

FORECASTS EXAMINING MODEL RUN TO RUN CONSISTENCY YIELDS A SLIGHTLY

BETTER AGREED UPON ECMWF SOLUTION WHICH LOOKS CLOSEST TO THE 00Z

ECMWF MEAN. THIS WAS USED AS A BASE WITH MANUAL ADJUSTMENTS.

HIGH PRESSURE BUILDING INTO THE GREAT BASIN SHOULD BRING AN

OFFSHORE/SANTA ANA EVENT TO CA WED INTO THURS. A DIFUSE AREA OF

LOW PRESSURE SHOULD DEVELOP ALONG THE GLFMEX COAST FRI AND INTO

SAT AND MOVE OFFSHORE OF THE EAST COAST SAT AND SUN. RAIN

POTENTIAL ALONG THE GULF COAST AND SOUTHEAST COAST FRI AND SAT

WITH THE POSSIBILITY OF MORE WINTRY WEATHER ACROSS THE NRN EDGE OF

THE PRECIPITATION SHIELD IN THE INTERIOR PIEDMONT AND FOOTHILLS

AND POSSIBILY THE MID ATLC COASTAL PLAIN AS PER ECMWF ENS MEAN.

LOW CONFIDENCE FORECAST.

AN OVERALL BROAD TROUGH SETTING UP COAST TO COAST WILL KEEP MOST

OF CONUS BELOW NORMAL LATE WEEK AND WEEKEND.

ROSENSTEIN

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FYI: Some special sounding data will be launched around 18Z across TX/OK/AR/LA. There is even a suggestion of Winter RECON missions to better evaluate the situation ahead this week. Those are strong hints that there is certainly something ahead that requires as much data as possible...

NOUS42 KWNO 161339

ADMNFD

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE

NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD

1337Z SUN JAN 16 2011..CORRECTION...RELEASE SONDES TODAY NOT

TOMORROW...

THE 12Z NCEP MODEL PRODUCTION STARTED ON TIME..

12Z RAOB RECAP...

KPP/78970 - 10142; GROUND EQUIP PROBLEMS...

NCEP HPC IS REQUESTING 18Z SOUNDINGS FOR TODAY 1/16 FROM THE

FOLLOWING STATES TX..LA..OK..AR..THIS WOULD INCLUDE THE FOLLOWING

UPPER AIR SITES..72249 FWD..72250 BRO..72251 CRP..72261 DRT..72265

MAF..72363 AMA..72364 EPZ..72240 LCH..72248 SHV..72233 LIX..72340

LZK..72357 OUN..

74646 LMN..

THE REASON FOR THE REQUEST FOLLOWS...

IT WOULD BE BENEFICIAL TO THE MODEL GUIDANCE IF ALL UPPER AIR

SITES IN OKLAHOMA, ARKANSAS, TEXAS, AND LOUISIANA WERE ABLE TO

LAUNCH AN 18Z SET OF BALLOONS/RADIOSONDES TODAY 1/16 TO HELP

BETTER INITIALIZE THE INTERACTION BETWEEN A SOUTHERN STREAM TROUGH

MOVING OUT OF MEXICO AND A NORTHERN STREAM TROUGH EMERGING EAST OF

THE ROCKIES. THIS SHOULD RESULT

IN LESS SPREAD IN THE DETERMINISTIC GUIDANCE COUPLED WITH THE

SCHEDULED WINTER WEATHER RECON.

A CRITICAL WEATHER DAY IS NOT EXPECTED IN THE NEXT 3 DAYS.

$$

SHRUELL/SDM/NCO/NCEP

This was the CARCAH assignment (Winter RECON) issued yesterday for today/tomorrow...

000

NOUS42 KNHC 151930

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

0230 PM EST SAT 15 JANUARY 2011

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

VALID 16/1100Z TO 17/1100Z JANUARY 2011

WSPOD NUMBER.....10-046

I. ATLANTIC REQUIREMENTS

1. FLIGHT ONE -- TEAL 70

A. A66/ DROP 10 (BOGGY)/ 17/1200Z

B. AFXXX 09WSA TRACK66

C. 17/0730Z

D. 10 DROPS AS PUBLISHED ON TRACK

E. AS HIGH AS POSSIBLE/ 17/1400Z

2. OUTLOOK FOR SUCCEEDING DAY:

A. POSSIBLE A66/ DROP 10 (BOGGY)/ 18/0000Z

B. POSSIBLE A62/ DROP 10 (TORRY)/ 18/1200Z

II. PACIFIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.

3. REMARK: G-IV WINTER STORM MISSION TASKED

IN WSPOD 10-045 WILL FLY AS SCHEDULED.

SEF

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HGX thinking we'll have a very messy afternoon/evening...

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

1138 AM CST SUN JAN 16 2011

.DISCUSSION... /ISSUED 1052 AM CST SUN JAN 16 2011/ INITIAL ROUND

OF RAINFALL IS GRADUALLY TAPERING OFF AT LATE MORNING. GPSMET DATA

SHOWS PLENTY OF MOISTURE IN PLACE WITH PWS RUNNING 1.0-1.2 INCHES.

KHGX VWP SHOWS A 30-35 KT LOW LEVEL JET WHICH WILL CONTINUE TO

TRANSPORT MOISTURE INTO THE AREA. WATER VAPOR IMAGERY SHOWS A

SECOND SHORTWAVE NOW OVER WEST TEXAS. THIS DISTURBANCE WILL CROSS

THE AREA THIS AFTN/EVENING RESULTING IN AN ENHANCEMENT IN RAINFALL

ONCE AGAIN. SOME ISOLATED THUNDER IS EXPECTED AS WELL AS A POCKET

OF VERY COLD 500 MB TEMPS (-20 TO -22C) MOVES OVER THE CWA.

LOCALLY HEAVY RAINS WILL BE POSSIBLE WITH THE NEXT ROUND AS WELL.

MADE SOME ADJUSTMENTS TO POPS OTHERWISE NO CHANGES TO FORECAST.

Also notice the Mountain Waves associated with a strong Northerly flow dropping S from the Rockies in Far W TX/S NM...

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Winter RECON schedule has updated...

NOUS42 KNHC 161830

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

0130 PM EST SUN 16 JANUARY 2011

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

VALID 17/1100Z TO 18/1100Z JANUARY 2011

WSPOD NUMBER.....10-047

I. ATLANTIC REQUIREMENTS

1. FLIGHT ONE -- TEAL 71

A. A65/ DROP 10 (STIFF)/ 18/0000Z

B. AFXXX 10WSA TRACK65

C. 17/1800Z

D. 10 DROPS AS PUBLISHED ON TRACK

E. AS HIGH AS POSSIBLE/ 18/0200Z

FLIGHT TWO -- TEAL 72

A. A65/ DROP 10 (STIFF)/ 18/1200Z

B. AFXXX 11WSA TRACK65

C. 18/0615Z

D. 10 DROPS ON TRACK AS PUBLISHED

E. AS HIGH AS POSSIBLE/ 18/1400Z

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

3. REMARK: WC-130 WINTER STORM MISSION TASKED

ON WSPOD 10-046 WILL FLY AS SCHEDULED.

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It is interesting to see that Midland/Odessa, San Angelo, Norman and Shreveport are all mentioning the possibility of a wintry mix on Thursday. They all suggest that their temps may be too warm as well. And then the discussion begins to turn toward next weekend and another reinforcing shot of cold air and another Upper Air disturbance. Just another boring week ahead... :arrowhead:

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A little better agreement this morning via the Opertaional models, but still a bit of a spread within the ensembles and those operational models. The HPC spells out the differences and suggests the Euro is the best fit, for now...still looks like a icy Thursday from the Hill Country to NE TX...later in the medium/longer range, an unsettled pattern looks to remain in place as well...

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

801 AM EST MON JAN 17 2011

VALID 12Z FRI JAN 21 2011 - 12Z MON JAN 24 2011

EXPECT A LARGE SCALE MEAN TROF TO PERSIST OVER THE ERN HALF OF

CANADA INTO THE ERN HALF TO 2/3 OF THE CONUS FOR MOST OF THE

PERIOD. THERE ARE INDICATIONS THAT THE RIDGE OVER THE ERN PAC

WILL TRY TO BUILD INTO THE NWRN CONUS/WRN CANADA BY EARLY NEXT

WEEK. DIFFS STILL EXIST WITH DETAILS AMONG LATEST MODEL/ENSEMBLE

SOLNS AND CONSECUTIVE RUNS OF INDIVIDUAL MODELS BUT AS A WHOLE

AGREEMENT APPEARS TO HAVE IMPROVED COMPARED TO RECENT DAYS.

DAYS 3-5 THU-SAT MAINTAIN A SOLN SIMILAR TO THE 00Z ECMWF. AS OF

EARLY DAY 3 THU THERE ARE TIMING DIFFS WITH THE COLD FRONT SURGING

THRU THE SRN PLAINS WITH THE 00Z/06Z GFS SLOWER THAN ECMWF-BASED

GUIDANCE. NEITHER SCENARIO IS AN OUTLIER COMPARED TO THE FULL

SOLN SPREAD. GIVEN THAT SUCH SURGES CAN SOMETIMES BE FCST A

LITTLE TOO SLOW... THE FASTER PORTION OF THE ENVELOPE SEEMS

REASONABLE. BY DAY 4 FRI THERE IS A MODERATE AMOUNT OF SPREAD

REGARDING POSSIBLE SFC DEVELOPMENT NEAR THE EAST COAST. THE 00Z

CANADIAN IS A DEEP/WWD EXTREME COMPARED TO OTHER MODEL/ENSEMBLE

SOLNS AND THE 06Z GFS IS RATHER FAR WWD AS WELL. THE 00Z GEFS

MEAN IS A SLOWER AND SLIGHTLY WEAKER VERSION OF THE 00Z ECMWF. ON

THE OTHER HAND THE UKMET AND CANADIAN/ECMWF ENSEMBLE MEANS SHOW

LESS DEVELOPMENT THAN THE 00Z ECMWF... LEAVING THE 00Z ECMWF AS A

GOOD INTERMEDIATE SOLN AT THIS TIME. BY DAY 5 SAT THE MAIN

FEATURE OF NOTE IS A WAVE REACHING THE PLAINS OR MS VALLEY. A

FASTER TREND OF THE 06Z GFS VERSUS THE 00Z GFS/GEFS MEAN ADD

SUPPORT TO THE 00Z ECMWF SCENARIO BUT THERE REMAINS ENOUGH

TIMING/DETAIL SPREAD TO KEEP CONFIDENCE MEDIUM TO LOW. FARTHER

WWD THE 00Z ECMWF IS ONE OF THE STRONGER SOLNS WITH A SHRTWV

REACHING THE NWRN CONUS BY EARLY SAT. THIS FEATURE IS FARTHER NWD

IN THE 00Z CMC AND HINTED AT IN WEAKER FORM BY ECMWF ENSEMBLES AND

THE UKMET. WILL AWAIT 12Z GUIDANCE FOR ANY CONFIDENT ADJUSTMENTS

TO THE ECMWF HANDLING OF THIS FEATURE IN LIGHT OF ECMWF PREFERENCE

ELSEWHERE.

DAYS 6-7 SUN-MON INCORPORATE 50-60 PCT OF THE 00Z ECMWF ENSEMBLE

MEAN WITH THE 00Z ECMWF AS CONFIDENCE DECREASES IN THE SPECIFICS

OF THE OPERATIONAL RUN. THE 00Z ECMWF IS WITHIN THE FULL SOLN

SPREAD OVER THE WEST/PLAINS BUT CURRENT MODEL/ENSEMBLE DIFFS AND

ECMWF RUN TO RUN CONTINUITY CHANGES REQUIRE A BLENDED APPROACH TO

ACCOUNT FOR UNCERTAINTY. MEANWHILE ENSEMBLE SUPPORT IS LACKING

FOR THE 00Z ECMWF IDEA OF A WELL DEFINED SFC LOW BEING LOCATED OFF

THE NEW ENGLAND COAST AS OF EARLY DAY 7 MON... AS GUIDANCE

CONSENSUS SHOWS BROADER FLOW ALOFT THAN FCST BY THE 00Z ECMWF.

THE PREFERRED BLEND STILL YIELDS A WEAK WAVE BUT IS MUCH CLOSER TO

THE MIDDLE OF THE FULL ARRAY OF GUIDANCE.

RAUSCH/CISCO

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