Texas/MX Obs And Discussion Thread.

[Srain]

Several things to watch in the Christmas Eve to New Years time frame. The storm track is shifting and that is a change. There appears to be a chance of severe weather to our NE with the Christmas Eve front. The front on the 28th is suggested by virtually all the global operational guidance (GFS, Euro, Canadian, & UKMET) to be a powerful Southern Plains storm. While the track will shift and certainly is not set in stone at this range, the fact that all medium range guidance is 'sniffing' out the storm brings some hope that it will be there in some form or fashion and end this run of a boring weather pattern.

[Srain]

We seem to be heading in the right direction, Jorge. The 12Z GFS suggests the Christmas Eve front is still on schedule and a robust storm takes shape across the Southern Plains and heads E. There are some positive signals of a pattern change as well. The Pacific appears to be heading toward a more favorable period and we are seeing signs of an MJO pulse that could invigorate the STJ. Also of note is the rising PNA depicted in the guidance as well. The Pacific flow of storms appears to reamain very active and hopefully the more active period will produce some better chances of moisture for TX/OK...

PNA heading toward a netural/slightly positive regime after being negative since mid November...

AO is expected to stay negative after dropping to a record negative range today (-5.17)...

[Srain]

Good to see HM coming onboard, isn't it Jorge...

http://www.americanwx.com/bb/index.php?/topic/4123-why-the-final-week-of-dec-is-trouble/

I'm still dreaming of a wet and maybe even white New Years Eve...

[Srain]

Some shifts in guidance for the Christmas Eve Storm have occurred overnight. A very complex and complicated forecast is ahead and expect some changes. The Euro, Canadian and UKMET has trended further S and stronger with an Upper Air feature (closed low) tracking across Southern California, Desert SW into the TX Panhandle and dropping ESE into LA, while the GFS keeps an open wave/trough further N exiting CO into KS and heading E. Now what does that mean? It appears more moisture may be involved with the Christmas Eve front and perhaps a 6-12 hours slower arriving Friday afternoon/evening versus the faster GFS solution. Also of note with the Euro solution is the chance of rain and possibly elevated storms across the TX Panhandle, W TX, N TX/OK along and N of the Upper Low track, should it verify. Christmas Day still looks cold and dry for now, but if the Euro solution is correct, there may well be some wrap around cloudiness/very light moisture and stiff northerly winds as a surface low pressure deepens over LA. The Euro solution also opens the door to a Major Christmas Weekend Winter Storm along the East Coast as well with very heavy snowfall totals and even a 'hint' of an Archambualt Signature for that area. In the longer range the pattern as well as guidance suggests a bonified chance at some much needed rain in Southern, SE TX as a coastal low/trough develops during the pre New Years Eve time frame. We have been hoping for some sort of pattern change and this may well be it.

Forecaster Roth in the HPC morning Prelim Update...

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

757 AM EST MON DEC 20 2010

VALID 12Z FRI DEC 24 2010 - 12Z MON DEC 27 2010

...SIGNIFICANT PRECIPITATION EXPECTED TO CONTINUE ALONG AND JUST

INLAND OF THE WEST COAST FOR ANOTHER 5 TO 6 DAYS...

TELECONNECTIONS WITH A RIDGE MOVING SLOWLY ACROSS THE PRAIRIE

PROVINCES OF CANADA FAVORS NEARLY CLOSED CYCLONES ALOFT MOVING

UNDER ITS BASE THROUGH THE NORTHERN ROCKIES/NORTHERN PLAINS LATER

THIS WEEK...A SOLUTION BEST INDICATED BY THE 00Z CANADIAN AND 00Z

GEFS AND ECMWF ENSEMBLE MEAN GUIDANCE. OTHERWISE...ENERGY MOVING

OUT INTO THE MIDWEST EARLY ON IS EXPECTED TO SCOOP UP SOME

SHORTWAVE ENERGY MOVING OUT OF THE SOUTHWEST AND SOUTHERN PLAINS

BEFORE LOSING LATITUDE AS IT MOVES THROUGH THE EAST UNDER THE BASE

OF A PORTION OF THE POLAR VORTEX DESCENDING THROUGH EASTERN

CANADA. THIS SOLUTION IS BEST REPRESENTED BY THE 06Z GFS/00Z

CANADIAN/00Z ECMWF AND GEFS MEAN GUIDANCE. OVERALL...USED A

COMPROMISE OF THE 00Z CANADIAN/00Z ECMWF ENSEMBLE MEAN...AS THE

06Z GFS MIGHT BE A TOUCH TOO QUICK PER ITS OCCASIONAL QUICK BIAS

WITH SYSTEMS IN THE WESTERLIES...WHICH LED TO GOOD CONTINUITY WITH

THE PRESSURES FROM SUNDAY AFTERNOON. THIS PATTERN SHOULD REMAIN

MOIST ALONG THE WEST COAST...AND COLD ACROSS THE NORTHERN

PLAINS/MIDWEST/MUCH OF THE EAST.

WEST AND PLAINS THIS WEEKEND INTO EARLY NEXT WEEK...

WITH STRONG RIDGING PERSISTING ACROSS WESTERN AND CENTRAL CANADA

THROUGH THE PERIOD...A PACIFIC SYSTEM IS EXPECTED TO MOVE THROUGH

THE REGION UNDERCUTTING THE RIDGE. TIMING ISSUES EXIST...WITH THE

06Z GFS THE QUICKEST. SINCE THE RIDGING ACROSS WESTERN AND

CENTRAL CANADA IS SHOWING SOME PROGRESSION IN THE NORTHERN

STREAM...A SLOWER PROGRESSION IS LIKELY IN THE SOUTHERN

STREAM...SO WENT WITH THE NON-06Z GFS GUIDANCE HERE.

OVERALL...THE 00Z CANADIAN HAD THE BEST ENSEMBLE MEAN SUPPORT...SO

WENT WITH A 00Z CANADIAN/00Z ECMWF ENSEMBLE MEAN COMPROMISE WITH

THIS SYSTEM. SIGNIFICANT PRECIPITATION ACROSS THE WEST IS

EXPECTED FOR ANOTHER 5 TO 6 DAYS...WITH LOCAL LIQUID EQUIVALENT

AMOUNTS OF 10 INCHES POSSIBLE ACROSS THE OLYMPIC

PENINSULA...NORTHERN COASTAL RANGES OF CALIFORNIA AND SISKIYOU

RANGE...AS WELL AS THE COASTAL RANGES OF SOUTHERN CALIFORNIA AND

SOUTHERN WASATCH DURING THIS TIME FRAME.

SOUTH AND EAST...

THE 00Z ECMWF IS SLOW/MORE CLOSED THAN THE OTHER DETERMINISTIC

GUIDANCE WITH ENERGY MOVING THROUGH THE SOUTHWEST AND SOUTHERN

PLAINS...WITH LESS THAN ONE-QUARTER OF THE OVERALL 00Z GLOBAL

ENSEMBLE GUIDANCE SUPPORTING ITS SOLUTION...IMPLYING IT IS TOO

SLOW. TELECONNECTIONS FARTHER NORTH IMPLY STRONGER ENERGY SHOULD

BE MOVING THROUGH THE NORTHERN TIER OF THE COUNTRY...WHICH SHOULD

ABSORB THE SOUTHWESTERN ENERGY AS IT MOVES INTO THE

PLAINS/MIDWEST. EITHER WAY...A SURFACE LOW IS EXPECTED TO MOVE

THROUGH THE SOUTHERN PLAINS INTO THE DEEP SOUTH OR TENNESSEE

VALLEY OFFSHORE THE VIRGINIA CAPES. THE BIGGER QUESTION IS HOW

CLOSE TO THE COAST THIS CYCLONE WILL TRACK. THE ECMWF BECOMES THE

MOST NORTHWESTERLY OF THE GUIDANCE AT THE SURFACE...AND IF THIS

SURFACE LOW WERE MOVING UP THE EAST SIDE OF AN AMPLIFIED TROUGH

RATHER THAN A PROGRESSIVE CLOSED CYCLONE A MORE COASTAL TRACK FOR

NEW ENGLAND WOULD MAKE SENSE. SINCE THIS DOES NOT APPEAR TO BE

THE CASE...AND THE 00Z ECMWF ALSO APPEARS TOO FAR NORTH WITH ITS

CYCLONE IN CANADA...ITS CYCLONE TRACK ALONG THE EAST COAST IS

PROBABLY TOO FAR NORTH/TOO CLOSE TO THE COAST. THE OTHER

GUIDANCE...INCLUDING THE ENSEMBLE MEAN SOLUTIONS...MOVE THIS

SYSTEM CLOSER TO THE GULF STREAM...A NATURAL BAROCLINIC ZONE/AREA

OF TEMPERATURE GRADIENT OFFSHORE THE EAST COAST...WHICH APPEARS

MORE LIKELY CONSIDERING THE FLOW PATTERN ALOFT. DUE TO

PREFERENCES ACROSS THE PLAINS AND WEST LATE IN THE PERIOD...CHOSE

THE 00Z CANADIAN HERE...ALTHOUGH THE 00Z ECMWF OR 00Z GEFS MEAN

ARE REASONABLE ALTERNATIVES. EITHER WAY...WINTER WEATHER SHOULD

SPREAD FROM THE CENTRAL PLAINS EASTWARD ACROSS THE TENNESSEE

VALLEY THROUGH THE MID-ATLANTIC STATES...AS WELL AS SNOW SHOWERS

UNDER THE BASE OF THIS SYSTEM ACROSS THE GREAT LAKES AND

NORTHEAST. THE IMPACT OF THIS SYSTEM ACROSS THE NORTHEAST REMAINS

SOMEWHAT OF A QUESTION MARK...BUT FOR THE TIME BEING...THE 00Z

ECMWF LOOKS LIKE A LOWER PROBABILITY ALTERNATIVE SCENARIO.

ROTH

[Srain]

The big question this morning in light of the over night guidance appears to be is the Euro correct with a close Upper Low tracking across TX for Christmas Eve? If it is correct, rain chances would increase across the Lone Star State with the nice return flow that is well established in our area (SE TX). Also, the cold front does appear to be a rather strong one and the development of an East Coast Winter Storm looks to keep those cool temps in place longer for Christmas Day weekend. Fingers crossed as the pattern suggests some rain chances during the pre New Years Eve time frame as well.

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

902 AM EST TUE DEC 21 2010

VALID 12Z SAT DEC 25 2010 - 12Z TUE DEC 28 2010

...CONTINUED WET ACROSS THE PACIFIC NORTHWEST...

...BELOW NORMAL TEMPS FROM THE PLAINS EASTWARD...

...POTENTIAL EAST COAST WINTER STORM SAT-MON...

THE NORTH ATLANTIC OSCILLATION INDEX REMAINS NEGATIVE THIS MORNING

WITH A LARGE POSITIVE MID-LEVEL HEIGHT ANOMALY EXTENDING FROM

GREENLAND WESTWARD TOWARD HUDSON BAY WHICH IS BLOCKING THE

UPSTREAM FLOW...MUCH OF WHICH IS EXPECTED TO ORIGINATE FROM AN

INTENSE POLAR JET STREAM TRAVERSING THE BASE OF A QUASI-STATIONARY

UPPER CYCLONE OVER THE GULF OF ALASKA THROUGH THE MEDIUM RANGE

PERIOD.

MODEL AGREEMENT WITH THE LARGER-SCALE ASPECTS IS QUITE GOOD TO

BEGIN THE PERIOD. HOWEVER...THIS IS NOT THE CASE OVER THE CENTRAL

CONUS WHERE THE FLOW BEGINS TO SPLIT...WITH THE 00-06Z GFS/00Z

CANADIAN FASTER AND MORE AGGRESSIVE THAN THE 00Z ECMWF/UKMET IN

ALLOWING THE FLOW TO PHASE OVER THE MISSISSIPPI/TENNESSEE VALLEYS

BY DAYS 4/5. SEVERAL ASPECTS...INCLUDING RECENT SATELLITE TRENDS

OVER THE EASTERN PACIFIC SHOWING AN INTENSE POLAR JET TRAVERSING

THE WESTERN PERIPHERY OF AN ACCOMPANYING UPPER TROUGH...HIGHER

SPATIAL RESOLUTION OF THE ECMWF...AND MORE SOPHISTICATED

INITIALIZATION OF THE ECMWF...FAVOR AN ECMWF-LIKE SOLUTION VERSUS

THE 00-06Z GFS...IN ALL AREAS. HOWEVER...GIVEN THAT EVEN THE ECMWF

CAN NOT ACCOUNT FOR UNCERTAINTY IN INITIAL CONDITIONS...FEEL IT IS

MOST PRUDENT TO ADD INCREASING WEIGHT FROM ITS OWN ENSEMBLE MEAN

THROUGH THE ENTIRE PERIOD. THUS...THE UPDATED PRESSURES/FRONTS

WILL BEGIN WITH A 90/10 ECMWF/ECMWF ENSEMBLE MEAN BLEND

RESPECTIVELY DAY 3...WHILE GRADUALLY TRANSITIONING TOWARD A 40/60

ECMWF/ECMWF ENSEMBLE MEAN BLEND RESPECTIVELY BY DAY 7.

REGARDING SIGNIFICANT IMPACTS...THE PACIFIC NORTHWEST EXTENDING

PERHAPS AS FAR SOUTH AS THE SIERRAS WILL REMAIN UNDER THE

INFLUENCE OF AN UNUSUALLY STRONG POLAR JET STREAM EMBEDDED WITH

PERIODS OF HEAVY PRECIPITATION. DAYS 4/5 AND DAYS 6/7 QPF ACROSS

THE WEST ARE EXPECTED TO RANGE BETWEEN 2 AND 5 INCHES POSSIBLY

HIGHER...WITH THE LAST 2 RUNS OF THE ECMWF AND ITS MOST RECENT

ENSEMBLE MEAN USED AS A 1ST GUESS. MEANWHILE...THE EVOLVING TROUGH

OVER THE GREAT LAKES/OHIO VALLEY EARLY IN THE PERIOD FAVOR BELOW

NORMAL TEMPERATURES FOR ALL AREAS FROM THE PLAINS EASTWARD...WITH

SUBFREEZING TEMPERATURES POSSIBLY RETURNING THE ENTIRE GULF COAST

REGION AND MUCH OF FLORIDA BY DAYS 6/7. FINALLY...AN ECMWF-LIKE

SOLUTION FAVORS A WINTER STORM BEGINNING TO DEVELOP NEAR THE

SOUTHEAST COAST BY DAY 4 BEFORE ACCELERATING UP THE EAST COAST

DAYS 5/6. IT IS STILL TOO EARLY TO BE DEFINITIVE WITH THE PRECISE

DETAILS INCLUDING TRACK OF THIS SYSTEM AS MODEL SPREAD CONSIDERING

THE SPLIT-FLOW UPSTREAM BECOMES QUITE LARGE. WHILE THE 00Z ECMWF

IS MOST PREFERRED...MANY OF ITS OWN ENSEMBLE MEMBERS ARE BOTH

FASTER AND SLOWER WITH THE TRACK OF THE LOW WHICH HAS HUGE

IMPLICATIONS FOR THE ENTIRE EAST COAST. THUS...GIVEN THE

UNCERTAINTIES AND SPREAD...THE UPDATED TRACK ALONG THE EAST COAST

WAS MORE HEAVILY WEIGHTED TOWARD ITS OWN ENSEMBLE MEAN ESPECIALLY

LATE IN THE PERIOD.

JAMES

[somethingfunny]

Record High Status:

TOAST!!!

The old record was 82°.

Dallas / Fort Worth International Airport

Lat: 32.91 Lon: -97.03 Elev: 560

Last Update on Dec 21, 1:53 pm CST

Partly Cloudy

83 °F

(28 °C)Humidity:15 %Wind Speed:W 8 MPHBarometer:29.88" (1011.3 mb)Dewpoint:31 °F (-1 °C)Heat Index:80 °F (27 °C)Visibility:10.00 mi.

[Srain]

Record or tied maximum and high minimums at College Station, IAH and Hobby. Ouch...that front on late Christmas Eve is going to be welcome relief...

[wxmx]

The period for enhanced wintry chances for our areas is on track. An active STJ looks likely, but real cold seems elusive...but models are hinting at a chance early in Jan. Teleconnections are zeroing around the same time:

And of course :

[Srain]

Yep. The end of December, first week of January just keep popping up.

[TXWXCHX]

This will be my Christmas present if it actually rains!! Interesting days ahead...

[msp]

Glad i haven't missed anything more than another helping of unseasonable warmth. Looks like a drizzle warning may be needed for tomorrow. Y'all need to get to work on delaying that winter weather potential for a week or so til I'm down for the cotton bowl.

[Srain]

SPC says Merry Christmas...rain and elevated storms....

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1200 AM CST WED DEC 22 2010

VALID 231200Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

EXPECT LONGWAVE TROUGHING OFF W AND E COASTS...AND RIDGING OVER

CENTRAL NORTH AMERICA. SRN BRANCH OF SHORTWAVE TROUGH -- NOW

EVIDENT IN MOISTURE CHANNEL IMAGERY OFFSHORE CA COAST INVOF

130W-132W -- WILL MOVE INLAND DAY-1 AND REACH NRN AZ BY

23/12Z...PERHAPS WITH ACCOMPANYING SMALL/CLOSED CYCLONE AT 500 MB.

MOST SREF MEMBERS STILL ARE NOTICEABLY FASTER THAN DETERMINISTIC

MODELS WITH THIS SYSTEM. WHILE OPERATIONAL WRF APPEARS TO REMAIN

SLOWEST PROG...OTHER MODELS HAVE TRENDED TOWARD WRN-MOST SREF

OUTLIERS...AND TOWARD EVEN SLOWER WRF SOLUTIONS FOR SAME VALID

TIMES. OLDER/SLOWER WRF RUNS ALSO APPEAR TO BE VERIFYING BEST WITH

CURRENT POSITION/AMPLITUDE...WHILE SPECTRAL ALSO HAS SLOWED DOWN

THIS SYSTEM GREATLY. THEREFORE...WILL TREND FCST DECIDEDLY BEHIND

SREF CONSENSUS...AND MORE AKIN TO OPERATIONAL WRF/SPECTRAL POSITION

OF 500-MB TROUGH FROM SW KS TO PERMIAN BASIN BY END OF PERIOD.

IN RESPONSE...SFC CYCLOGENESIS FCST EARLY IN PERIOD OVER CENTRAL

CO...WITH LOW SHIFTING SEWD TOWARD NW TX/SERN PANHANDLE REGION BY

24/12Z. COLD FRONT WILL FORM OVER CENTRAL ROCKIES/HIGH PLAINS AND

MOVE SEWD ACROSS NERN NM AND TX PANHANDLE.

...AZ/NM...EARLY PERIOD...

ISOLATED TO WIDELY SCATTERED TSTMS MAY BE ONGOING AT 23/12Z OVER

PORTIONS AZ...WITH MRGL BUOYANCY AIDED BY PAC LOW-LEVEL MOISTURE AND

EFFECTS OF FAVORABLE MIDLEVEL COOLING ON LAPSE RATES ALOFT. REGIME

WILL SHIFT EWD ACROSS SRN PORTIONS 4-CORNERS REGION AND WRN

NM...WEAKENING AS IT LEAVES BEHIND MUCH OF BOUNDARY-LAYER

MOISTURE...BUT WITH A FEW LTG STRIKES POSSIBLE.

...PORTIONS SRN PLAINS TO WRN OZARKS REGION...

STG LOW-LEVEL WAA IS FCST ACROSS SRN/CENTRAL PLAINS THROUGHOUT

PERIOD...WRN PORTIONS OF WHICH WILL BE SUPERIMPOSED BENEATH

INCREASING LARGE-SCALE ASCENT/DCVA AND UPPER DIVERGENCE BY END OF

PERIOD...NEAR SFC LOW. ELEVATED LOW-LEVEL MOISTURE WILL BE

INCREASING WITH TIME THROUGHOUT DAY-2...IN PLUME FROM SW TX TO NERN

OK/SERN KS. PROBABILITY ALSO WILL INCREASE FOR PARCELS

ISENTROPICALLY LIFTED TO LFC...AMIDST INITIALLY VERY WEAK BUT

STEADILY INCREASING ELEVATED BUOYANCY. THEREFORE...BOTH SPOT

PROBABILITIES AND POTENTIAL AREAL COVERAGE OF THUNDER WILL INCREASE

THROUGH OVERNIGHT HOURS.

MULTITUDE OF RECENT FROPAS HAVE DEPLETED BOUNDARY-LAYER MOISTURE IN

UPSTREAM/GULF TRAJECTORIES. MARINE MODIFICATION SHOULD BE

INSUFFICIENT TO SUPPORT MORE THAN 40S-50S F SFC DEW POINTS N OF

I-10...WITH AIR MASS FARTHER S BEING CAPPED BENEATH MEXICAN ELEVATED

MIXED LAYER. THEREFORE...WHILE DEEP-LAYER SHEAR WILL BECOME

INCREASINGLY FAVORABLE OVERNIGHT...PARCELS WILL REMAIN ELEVATED

AMIDST WEAK CAPE GENERALLY AOB 300 J/KG. SVR POTENTIAL APPEARS TOO

SMALL/CONDITIONAL FOR PROBABILITIES.

..EDWARDS.. 12/22/2010

[Srain]

Glad i haven't missed anything more than another helping of unseasonable warmth. Looks like a drizzle warning may be needed for tomorrow. Y'all need to get to work on delaying that winter weather potential for a week or so til I'm down for the cotton bowl.

Things are cooling off as the backdoor front has slipped much further S that progged this morning. Infact it may make it across the Houston area or a bit S. Better get back near the New Year time frame...

[wxmx]

In the long range, the pattern change started by the infamous California- E Coast s/w is showing as a non typical Niña, and 10+ days away it is a lot more like a Niño. The 12z GFS and it's ensembles are starting to show an Aleutian low, W coast ridging and Davis straits ridging the first week of January...that would be totally unexpected by me, since I didn't think the relatively favorable pattern for cold us south wouldn't last more than 10-15 days... and during climo's coldest weeks of winter to boot! This would be an MJO driven pattern change, with almost all guidance showing a coherent wave reaching phase 7. Needless to say, the progress of things should be watched carefully, as snow in the forecasts is starting to look more probable.

For this far out, the consensus for all 3 teleconnectors metioned above is astounding:

[Srain]

In the long range, the pattern change started by the infamous California- E Coast s/w is showing as a non typical Niña, and 10+ days away it is a lot more like a Niño. The 12z GFS and it's ensembles are starting to show an Aleutian low, W coast ridging and Davis straits ridging the first week of January...that would be totally unexpected by me, since I didn't think the relatively favorable pattern for cold us south wouldn't last more than 10-15 days... and during climo's coldest weeks of winter to boot! This would be an MJO driven pattern change, with almost all guidance showing a coherent wave reaching phase 7. Needless to say, the progress of things should be watched carefully, as snow in the forecasts is starting to look more probable.

For this far out, the consensus for all 3 teleconnectors metioned above is astounding:

Great information Jorge. The signals are stunning and now if the goods can get delivered.

[bubba hotep]

In the long range, the pattern change started by the infamous California- E Coast s/w is showing as a non typical Niña, and 10+ days away it is a lot more like a Niño. The 12z GFS and it's ensembles are starting to show an Aleutian low, W coast ridging and Davis straits ridging the first week of January...that would be totally unexpected by me, since I didn't think the relatively favorable pattern for cold us south wouldn't last more than 10-15 days... and during climo's coldest weeks of winter to boot! This would be an MJO driven pattern change, with almost all guidance showing a coherent wave reaching phase 7. Needless to say, the progress of things should be watched carefully, as snow in the forecasts is starting to look more probable.

For this far out, the consensus for all 3 teleconnectors metioned above is astounding:

Thanks for the thoughts. Your MJO and teleconnection insights are always greatly appreciated.

It is nice to see that we should be getting so much needed rain here in North Central Texas. However, it is a major bummer that I am not watching this storm unfold from the Alexandria, Va home! I cashed in on Winter 2002/03 and last winter up there but would hate to miss out on the "big one"

[Srain]

It appears we are going to have a Christmas present in the form of some badly needed rain...

[bubba hotep]

It appears we are going to have a Christmas present in the form of some badly needed rain...

Nice job by the GFS, it started playing around with the on or around Christmas day rain/snow possibility almost two weeks ago. I think back on the 7th it originally had it as snow for our area but mid-40s and rain isn't too big of a bust.

[Srain]

The longer range could get real interesting around here...

[TXWXCHX]

It appears we are going to have a Christmas present in the form of some badly needed rain...

Wait, that's not a Low! That's Santa's Sleigh bringing a Heavenly Christmas gift to Texas - RAIN!!!

So is this low the spawn of a Super Nina's Pineapple Express? If so, I can only hope we could expect more of the same (unfortunately, the people of California might not be as thrilled about it as we are...) Is there an year analogue for a rainy La Nina in Central Texas?

EDIT: This page, "Civil War Weather Detectives" might contain some clues to the Great California Flood of 1861-1862. They have analysis of Summer Missouri weather which leads them to believe that a La Nina was in effect during the years of 1861-1862, which might provide insight into historic teleconnections involved in the Great Cali Flood - and perhaps might lend some important data for predicting patterns in this year? I know it's the wrong season, but it could provide some help with data...

[Srain]

What a great sight to see this morning. Rain and elevated storms across the Lone Star State. Man, has it been a long time since we've seen such a sight...Merry Christmas everyone...enjoy the pattern change...

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0633 AM CST FRI DEC 24 2010

VALID 241300Z - 251200Z

...NO SVR TSTM AREAS FORECAST...

A WELL-DEFINED SHORTWAVE TROUGH OVER EASTERN NM/WEST TX WILL TRACK

EAST-SOUTHEASTWARD ACROSS TX TODAY. MEANWHILE...AN ASSOCIATED

SURFACE COLD FRONT WILL BEGIN TO SURGE SOUTHWARD ACROSS OK/TX AND

PROVIDE THE PRIMARY FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS.

DESPITE STRONG SOUTHERLY LOW LEVEL WINDS AHEAD OF THE FRONT...LOW

LEVEL MOISTURE RETURN WILL BE QUITE LIMITED WITH ONLY MARGINAL

INSTABILITY EXPECTED TODAY. CONVECTION CURRENTLY OVER WEST-CENTRAL

TX WILL LIKELY PERSIST THROUGH THE DAY AND SPREAD SOUTHEASTWARD

TOWARD THE COAST. A FEW STRONG STORMS CANNOT BE RULED OUT THIS

AFTERNOON AND EVENING ACROSS CENTRAL TX AND THE MIDDLE TX GULF COAST

REGION. HOWEVER...PRESENT INDICATIONS ARE THAT SEVERE THREAT DOES

NOT WARRANT PROBABILITIES.

..HART/SMITH.. 12/24/2010

[bubba hotep]

Finally some rain up this way! We should be in for a nice soaking from the look of the radar.

[Srain]

Great to get about an inch of badly needed rainfall last evening. We also had several reports of flurries mixing with light rain around 11 PM last night just N of the Houston Metro (Rural Montgomery County). A balmy 39 with mist and drizzle this morning. What a change!

[Srain]

Wow, temps have dropped well below freezing in NW Harris County (27 at this hour) even with some light winds. It appears the coldest air of the season will settle into SE TX tonight and then we shift to an interesting week ahead. Guidance suggests a robust Coastal trough/low pressure will move N into Central TX increasing rain chances Tuesday/Wednesday and warm up there after as a powerful storm takes shape in the SW dropping a very deep trough into the Western CONUS. There are some differences between the GFS and Euro, but what is consistent is the continued advertisement of a very strong storm in the Southern and Central Plains with both severe and winter sides affecting parts of TX. We will need to watch this event closely as the week progresses as it could bring some interesting weather both Friday and Saturday into our region in time for the New Year. Stay tuned as they say.

[msp]

looks like CLL managed 0.67" a couple days ago. it'll help, but it's nowhere near a drought buster.

[Srain]

Another hard freeze this morning in SE TX with 26 for 5 hours so far in NW Harris County. Things look to get interesting Tuesday through Thursday for Central and Eastern TX with a robust short wave approaching and bringing some high percentage rain chances. The QPF totals are very encouraging and a chance at some strong storms/MCS as well. HGX is mentioning the possibility of heavy rainfall and hail. We certainly have shifted from our boring weather pattern of the past couple of months toward a more active period.

HPC:

SRN STREAM SHRTWV ENERGY ADVANCING EWD OUT INTO THE SRN PLAINS ON

TUE WILL BE INTERACTING WITH AN INCREASING SRLY RETURN FLOW OF

MOISTURE FROM THE GULF OF MEXICO BY LATER IN THE DAY AND THROUGH

EARLY WED. THE RESULT SHOULD BE THE DEVELOPMENT AND EXPANSION OF

AN AREA OF SHWRS/TSTMS ACRS CNTRL/ERN TX AND INTO MUCH OF THE LWR

MS VLY. THE GUIDANCE HAS TRENDED A LITTLE MORE ROBUST OVER THE

LAST DAY OR SO WITH THE MID LVL FORCING/DYNAMICS AND THIS SHOULD

HELP YIELD A STRONGER EVOLUTION OF CONVECTION WITH THE EXPECTATION

OF A MORE CONCENTRATED/ORGANIZED BAND OF CONVECTION MOVING EWD

ACRS THE WRN GULF COAST ON WED WITH HVY RAINFALL AMTS. THE

ECMWF/GFS SOLNS ARE DEPICTING A WELL-DEFINED LOW LVL JET OF UP TO

40 KTS AND A POOL OF 1.25 TO 1.5 INCH PWATS CROSSING FAR SERN

TX/LA AND COINCIDING WITH THE ARRIVAL OF THE UPR LVL SUPPORT.

EXPECT A FAVORABLE THERMODYNAMIC ENVIRONMENT FOR THE CONVECTION

AND WHAT WILL LIKELY QUALIFY AS AN MCS. THE ENERGY/CONVECTION

THOUGH SHOULD MOVE EWD WED NIGHT/THU TWD THE CNTRL GULF

COAST...AND IT IS EXPECTED TO WEAKEN WITH TIME AS IT ENCOUNTERS A

MORE STABLE BNDRY LYR. THE UPR LVL SUPPORT SHOULD ALSO BE

GRADUALLY SHEARING OUT/WEAKENING. HPC PREFERRED A SOLN TWD THE

WETTER GFS/ECMWF SOLNS...WITH THE HEAVIER AMTS ADJUSTED CLOSER TO

THE GULF COAST.

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1246 AM CST MON DEC 27 2010

VALID 281200Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A RELATIVELY LOW AMPLITUDE/PROGRESSIVE/SPLIT LARGE SCALE UPPER FLOW

REGIME IS EXPECTED TO BE PREVALENT OVER THE CONUS BY TUESDAY.

SEVERAL LOW AMPLITUDE SHORTWAVE TROUGHS ARE EXPECTED TO CROSS THE

SOUTHERN TIER OF THE CONUS...WITH TSTM POTENTIAL INCREASING TUESDAY

NIGHT ACROSS EAST TX/ARKLATEX. ADDITIONALLY...NEAR-COASTAL/OFFSHORE

TSTMS WILL BE POSSIBLE ACROSS THE PACIFIC NORTHWEST TUESDAY

NIGHT/EARLY WEDNESDAY AS AN UPPER TROUGH DEEPENS ALONG THE NORTHWEST

COAST.

...SOUTHEAST/EAST-CENTRAL TX TUESDAY NIGHT...

IN TANDEM WITH A PROGGED SOUTHERN STREAM SHORTWAVE TROUGH...LARGE

SCALE HEIGHT FALLS/WARM ADVECTION SHOULD CONTRIBUTE TO

GRADUAL/MODIFIED MOISTURE RETURN AND INCREASING TSTM POTENTIAL

TUESDAY NIGHT/EARLY WEDNESDAY ACROSS SOUTHEAST TX TO THE ARKLATEX.

GIVEN THE RECENT FRONTAL INTRUSION ACROSS THE GULF/CARIBBEAN AND

CURRENTLY OBSERVED TRAJECTORIES...QUALITY MOISTURE RETURN IS

UNLIKELY AND A RELATIVELY LIMITED BUOYANCY ENVIRONMENT IS PROBABLE

THROUGH THE END OF THE PERIOD. ACCORDINGLY...MUCH OF THE CONVECTION

INLAND TUESDAY NIGHT COULD REMAIN ELEVATED ABOVE A MARGINALLY

MOIST/BUOYANT NEAR-SURFACE LAYER. WHILE FAVORABLE WIND FIELDS

COMBINED WITH INCREASING BUT MODEST MOISTURE COULD PERHAPS SUPPORT A

FEW STRONG/POSSIBLY ROTATING STORMS TUESDAY NIGHT/EARLY

WEDNESDAY...THE OVERALL SEVERE POTENTIAL APPEARS LOW SUCH THAT

PROBABILITIES ARE NOT CURRENTLY WARRANTED.

..GUYER.. 12/27/2010

[Srain]

The 12Z NAM continues to advertise a wet/stormy pattern in the Tuesday/Wednesday time frame. Infact the NAM suggests a rather strong vort max swinging through near the Wednesday 12Z time frame with a possible MCS near the Middle/Upper TX Coast. Certainly some interesting weather to be mindful of as we head toward the New Year. Edit to add the 12Z GFS 60 hour precip totals...

[Srain]

Great news for our drought parched region as a robust short wave and multiple disturbances will rotate across the region...

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0640 AM CST TUE DEC 28 2010

VALID 281300Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...TX/OK/AR...

A BROAD UPPER TROUGH OVER NORTHERN MEXICO AND AZ/NM WILL MOVE SLOWLY

EASTWARD AND ACROSS TX DURING THIS FORECAST PERIOD. SOUTHERLY LOW

LEVEL WINDS AHEAD OF THE TROUGH WILL TRANSPORT GULF MOISTURE

NORTHWARD WITH SURFACE DEWPOINTS CLIMBING INTO THE 50S AS FAR NORTH

AS THE RED RIVER BY WED MORNING. INCREASING LOW LEVEL WARM

ADVECTION AND LIFT WILL LIKELY RESULT IN SCATTERED SHOWERS AND

THUNDERSTORMS BY EVENING OVER PORTIONS OF CENTRAL TX...DEVELOPING

NORTHWARD INTO SOUTHEAST OK AND SOUTHWEST AR BY 29/12Z. WEAK LAPSE

RATES/INSTABILITY SHOULD PRECLUDE SEVERE STORMS.

...PACIFIC NORTHWEST COAST...

THE NEXT UPPER TROUGH AND STRONG MID/UPPER LEVEL JET WILL BEGIN

AFFECTING THE PACIFIC NORTHWEST COAST LATER TODAY. RAPID COOLING

ALOFT AND STRONG LARGE SCALE FORCING WILL INCREASE THE RISK OF A FEW

LIGHTNING STRIKES...MAINLY AFTER 29/06Z.

..HART/SMITH.. 12/28/2010

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1257 AM CST TUE DEC 28 2010

VALID 291200Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

THE LARGE SCALE PATTERN OVER THE CONUS IS EXPECTED TO REAMPLIFY INTO

WEDNESDAY...HIGHLIGHTED BY A DEEPENING LONGWAVE TROUGH OVER THE

INTERMOUNTAIN WEST/GREAT BASIN. A FEW TSTMS MAY BE POSSIBLE ACROSS

THE COASTAL PACIFIC NORTHWEST WEDNESDAY MORNING WITHIN A

POST-FRONTAL ENVIRONMENT...BUT OTHERWISE...THE MAIN TSTM POTENTIAL

FOR THE PERIOD IS EXPECTED TO BE ACROSS EAST/SOUTHEAST TX AND LA.

...SOUTHEAST/EAST TX AND SOUTHERN LA...

SHOWERS/EMBEDDED TSTMS WILL BE ONGOING WEDNESDAY MORNING ALONG THE

TX COAST/MUCH OF EAST TX. WHILE A SHORTWAVE TROUGH/SPEED MAX

ADVANCES EAST-NORTHEASTWARD OVER TX/LA ON WEDNESDAY...THE AIRMASS

OVER THE GULF WILL CONTINUE TO MODIFY/GRADUALLY RETURN TOWARD THE TX

COAST. ASIDE FROM ONLY MODEST AIRMASS MODIFICATION INTO

WEDNESDAY...EXTENSIVE INLAND CONVECTION SHOULD ALSO DETER AN

APPRECIABLY MOIST AIRMASS MAKING IT INLAND ALONG THE TX/LA

COAST...WITH CONSEQUENTIAL NEAR-SURFACE DESTABILIZATION UNLIKELY

ESPECIALLY AWAY FROM THE IMMEDIATE COAST. BUT GIVEN MODERATELY

STRONG/VEERING LOW/MID TROPOSPHERIC WINDS...SOME POTENTIAL MAY EXIST

FOR A FEW ROTATING STORMS/A BRIEF TORNADO AND/OR STRONG WINDS MAINLY

ALONG THE IMMEDIATE TX/LA COAST WEDNESDAY...ALTHOUGH ANY SUCH THREAT

SHOULD REMAIN MARGINAL/ISOLATED OVERALL.

..GUYER.. 12/28/2010

HPC Day1:

...SCNTRL U.S....

BROAD POS TILTED SHRTWV MOVG ACRS THE SRN ROCKIES THIS MRNG WL

ENTER THE SRN PLNS LATER TDA/TNGT WITH SOME HGT FALLS/INCRSG

MID/UPR LVL SUPPORT THAT WL INDUCE DECENT DEEP LYRD LIFT FM NRN TX

INTO THE ARKLATX. MDLS ARE SHOWG WEAK UPR JET COUPLING DVLPG WITH

A POCKET OF STGR UPR LVL DVRG. DEEPER MSTR IS ALRDY WORKING INTO

SRN TX THIS MRNG WITH THE LATEST SATL DERIVED PWS LOOPS SHOWING

BOTH AN EPAC/CARIBBEAN CONNECTION THAT WL PROVIDE UNSEASONABLY

DEEP MSTR INTO THE REGION. PWS 1.00-1.25 INCHES ARE XPCTD TO BUILD

INTO THE REGION...BUT MDLS ALSO SHOW A POOL OF NR 1.50 INCH PWS

ALNG THE CNTRL TX CST. PW ANOMALIES ARE FCST TO BE 1-2 STDS ABV

NRML. 8H-7H FLOW FM THE S IS FCST TO BUILD TO 30-50 KTS THAT WL

PROVIDE MOD MSTR FLUX/THERMAL FORCG WITH THE MSTR LKLY TO BEGIN TO

POOL OVR NRN TX WHERE THE MDLS INDICATE A VRY WEAK ELEV BNDRY

FORMG. MDLS ARE GNRLY IN AGREEMENT WITH LGT PCPN DVLPG TDA OVR SRN

TX AND LIFTG/DVLPG NWD WITH ELEV CNVCTN DVLPG TNGT AS A LLJ FORMS.

MDLS FCST SOUNDGS ARE SHOWG SOME SMALL ELEV CAPE OF A FEW HUNDRED

J/KG THRU NRN TX/ARKLATX LATER TNGT. EXACT LAT/LON OF CNVCTV

DVLPMENT COULD BE ADJUSTED SWD IF DEEPER MSTR IS SEEN IN LATER

GUID. THE POOLG OF HIER PWS ALNG THE CNTRL TX CST LATER

TNGT...COULD ACTUALLY SUPPORT A SEPARATE SFC BASED AREA OF CNVCTN

LATER TNGT ALNG AN AREA OF WEAK CSTL CVRG.

HPC Day 2-3

SRN STREAM SHRTWV ENERGY ADVANCING EWD OUT INTO THE SRN PLAINS ON

WED WILL BE INTERACTING WITH AN INCREASING SRLY RETURN FLOW OF

MOISTURE FROM THE GULF OF MEXICO. THE MID LEVEL THETA-E ADVECTION

AND CONVERGENCE RESULTS IN THE DEVELOPMENT AND EXPANSION OF AN

AREA OF SHWRS/TSTMS ACRS CNTRL/ERN TX AND INTO MUCH OF THE LWR MS

VLY. THE 00Z GFS/NAM AND 12Z ECMWF SOLNS CONTINUE TO FCST A

WELL-DEFINED LOW LVL JET OF UP TO 40 KTS ALONG WITH A POOL OF NEAR

1.25 INCH PWATS CROSSING FAR SERN TX/LA...AND HENCE A MORE

FAVORABLE THERMODYNAMIC ENVIRONMENT FOR THE CONVECTION. THE

ENERGY/CONVECTION THOUGH SHOULD MOVE EWD WED NIGHT/THU ACRS THE

CNTRL GULF COAST...AND IT IS EXPECTED TO WEAKEN WITH TIME AS IT

ENCOUNTERS A MORE STABLE BNDRY LYR. THE UPR LVL SUPPORT SHOULD

ALSO BE GRADUALLY SHEARING OUT/WEAKENING TOO AND ONLY SCT ACTIVITY

IS EXPECTED TO SURVIVE INTO THE SOUTHEAST. HPC PREFERRED A SOLN

TWD THE WETTER 00Z GFS AND 00Z GEM REGIONAL SOLNS OVERALL...ALONG

WITH MORE CONCENTRATION OF CONVECTION CLOSER TO WRN GULF COAST

WHERE THE LOW LVL MOISTURE TRANSPORT AND CONVERGENCE SHOULD BE A

BIT BETTER DEFINED. A SEPARATE CONVECTIVE MAX THOUGH IS POSSIBLE

FARTHER NORTH ACRS CNTRL/SRN AR WHERE SOMEWHAT STRONGER MID LVL

DYNAMICS WILL BE CENTERED...AND ALSO A CARRYOVER FROM THE EXPECTED

DAY 1 ACTIVITY.

[Ed Lizard]

SWODY2 cautiously optimistic, "See Text/5% overall severe.

[Srain]

I'll bump our thread up as we have a nice event unfolding along the Middle and Upper TX Coast this morning. Heavy rainfall of an inch+ and surface as well as elevated storms are ongoing.