Texas winter wx thread (2009-2010)

[Portastorm]

I don't want a pipe buster...sorry.

Nor do I. Vodka cold without a snow/ice threat is a waste of good, cold Arctic air in my opinion!

(Portastorm begins his tiresome rant) But I've had my fill of cold with just enough snow flurries to count on two hands OR 40 degrees with rain. It's time for a bonafide wintry weather threat for south central Texas. North Texas has had two bites at the apple ... SE Texas one. Can it be our turn now?

[srainhoutx]

I don't want a pipe buster...sorry.

Nor do I. Vodka cold without a snow/ice threat is a waste of good, cold Arctic air in my opinion!

(Portastorm begins his tiresome rant) But I've had my fill of cold with just enough snow flurries to count on two hands OR 40 degrees with rain. It's time for a bonafide wintry weather threat for south central Texas. North Texas has had two bites at the apple ... SE Texas one. Can it be our turn now?

Just an FYI. The -AO dropping via ensembles to -6/-6.2 range. I suspect that we will see some waffling via guidance as this range of negative anomaly has only occurred 5 or 6 time since 1950. Also of note in the dropping of NAO and PNA as well. The signals would seem to indicate that with Cold Polar air in place and an active STJ, the chances continue to look interesting as we head into the first week of January Just something to think about.

http://www.cpc.noaa.gov/products/precip ... .sprd2.gif

http://www.cpc.noaa.gov/products/precip ... ensm.shtml

http://www.cpc.noaa.gov/products/precip ... ensm.shtml

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
855 AM EST WED DEC 30 2009

VALID 12Z SUN JAN 03 2010 - 12Z WED JAN 06 2010

TELECONNECTIONS WITH A NEGATIVE ANOMALY /THE POLAR VORTEX/ NORTH
OF THE NORTHWEST TERRITORIES OF CANADA COUPLED WITH A STRONG
POSITIVE MID-LEVEL ANOMALY /A CLOSED HIGH/ OVER SOUTHERN GREENLAND
FAVORS A SLOW-MOVING BUT PROGRESSIVE VORTEX NEAR THE
NORTHEAST/ATLANTIC CANADA AND A SOUTHERN STREAM NEAR THE US/MEXICO
BORDER. COMBINED WITH A DEEP CYCLONE CROSSING THE CENTRAL PACIFIC
THIS FAVORS RIDGING ACROSS WESTERN CANADA AND A REDEVELOPMENT OF A
MID-CONTINENT TROUGH BY THE END OF THE PERIOD. THE MODELS
GENERALLY SHARE THESE LARGER SCALE FLOW IDEAS QUITE WELL BUT
CONTINUE TO DIFFER WITH LESS PREDICTABLE SMALLER SCALE DETAILS.
RELATIVE MEASURE OF PREDICTABILITY VALUES /AT 500 MB/ PER THE GFS
ENSEMBLES ARE MAXIMIZED OVER THE EAST COASTS OF THE US AND CANADA
IN THE LARGER SCALE TROUGH WHILE THE WEST COAST SHOWS LOWER VALUES
AS DIFFERENCES IN SHORTWAVE TIMING/AMPLITUDE ARE EVIDENT.

THE 00Z ECMWF HAS MADE SIGNIFICANT POSITIVE CHANGES /INCREASED
HEIGHTS BY AT LEAST 60 METERS/ TO THE MID-LEVEL HEIGHT PATTERN
ACROSS THE DEEP SOUTH/FLORIDA WHEN COMPARED TO ITS PREVIOUS DAY OF
RUNS... BUT TAKES THE DEEP CYCLONE OFF THE NORTHEAST COAST WELL
NORTH AND WEST OF THE ECMWF/GFS ENSEMBLE MEAN POSITIONS INTO
CENTRAL QUEBEC. THE OPERATIONAL MODELS HAVE SHOWN A LARGE SHIFT IN
THE TRACK OF SAID CYCLONE... CLOSER TO THE COAST AND DEEPER... BUT
STILL SHOW GENERAL AGREEMENT OUTSIDE THE 00Z UKMET. A COLD AIRMASS
WILL BE IN PLACE ACROSS MUCH OF THE CENTRAL AND EASTERN US WITH
HIGH PRESSURE IN CENTRAL CANADA KEEPING NORTHERLY FLOW OVER THE
MISSISSIPPI VALLEY. THIS KEEPS MOST OF THE ACTION CONFINED TO THE
PAC NW BUT MAINLY THE NORTHEAST. NORTHERN NEW ENGLAND AND
ESPECIALLY MAINE COULD SEE ANOTHER HEFTY SNOWFALL AS THE DEEP SFC
LOW RETROGRADES TO JUST OFF THE COAST BEFORE LOOPING INTO THE GULF
OF ST. LAWRENCE BY TUE/D6.

KEPT REASONABLE CONTINUITY FROM OVERNIGHT ISSUANCE... WITH A
GENERAL 00Z ECMWF/CANADIAN BLEND EARLY BEFORE BRINGING IN THE
WELL-PERFORMING 00Z ECMWF ENSEMBLE MEAN. MODIFICATIONS INCLUDED
DEEPENING THE SYSTEM OFF THE MAINE COAST IN LINE WITH MANY OF THE
OPERATIONAL MODELS AND NUDGING ITS POSITION AS WELL.

ROTH/FRACASSO

[srainhoutx]

N TX folks may see another quick shot for some snow on New Years Eve. GFS and RGEM suggests more moisture with the short wave heading SE into TX behind the front.

[Ntxw]

N TX folks may see another quick shot for some snow on New Years Eve. GFS and RGEM suggests more moisture with the short wave heading SE into TX behind the front.

What about for the rest of Texas next week? Are the models still calling for very cold air or has it been pushed back\less cold?

[srainhoutx]

Pick your poison. GFS not as cold, but the 00Z ECMWF brings the colder Polar air due S into TX. We'll see what the 12Z suggests.

[Ntxw]

:uarrow: Pick your poison. GFS not as cold, but the 00Z ECMWF brings the colder Polar air due S into TX. We'll see what the 12Z suggests.

I would tend to trust the EC more than the gfs for that kind of longer trend. We'll see I guess =P

[wxgirl69]

when does the 12z come out?

[orangeblood]

The 12z ECMWF run comes out around 1pm central time.

[Tireman4]

Should be coming out now....

[orangeblood]

A few things stand out to me in regards to the model runs today:

1) cold polar air will be around all of next week
2) northwesterly flow will be established early next week
2) the shortwaves coming out of northwest Canada are going to be hard for the models to handle
3) right now the forecast looks dry due to the models not being able to pick up these shortwaves
3) it doesn't look like the sub tropical jet will be in play next week. but if we can get one of those shortwaves to dig into the four corners area then will be talking about another winter storm over the southern plains for the middle of next week.

[WacoWx]

thanks orangeblood. how cold did the model come in? we talking 40's for highs or 20's? I know its early but I want this thread to be as exciting as its been for the last few days/weeks.
Plus, I cant read the models and I would like some REALLY in depth analysis/opinions. demanding, i know.

[srainhoutx]

A few things stand out to me in regards to the model runs today:

1) cold polar air will be around all of next week
2) northwesterly flow will be established early next week
2) the shortwaves coming out of northwest Canada are going to be hard for the models to handle
3) right now the forecast looks dry due to the models not being able to pick up these shortwaves
3) it doesn't look like the sub tropical jet will be in play next week. but if we can get one of those shortwaves to dig into the four corners area then will be talking about another winter storm over the southern plains for the middle of next week.

Good analysis. A point I will make is that guidance has suggested that the S/W currently causing Winter Storm Watches/Wanrings to our NW was not suppose to be a moisture generator in TX. That infact has changed today via guidance. As far as Arctic Cold, the airmass next week is of a Polar/Canadian orgin. Those looking for a shallow stronger(much colder airmass) will need to look elsewhere for that.

[WacoWx]

which is colder: arctic or polar? i always thought the north pole was in the arctic circle.

[WacoWx]

nevermind, i think it was just answered.

[srainhoutx]

Arctic Airmass are much colder and shallower. With Arctic aimasses we often see temps in Denver warmer than here in TX. This is not good for snow growth. Polar/Canadian airmasses are deeper or higher in the atmosphere in most cases and that is what we would want to see for the entire column to be 'cold enough' to support snow. Simple answer, but hope it helps.

[attallaman]

Arctic Airmass are much colder and shallower. With Arctic aimasses we often see temps in Denver warmer than here in TX. This is not good for snow growth. Polar/Canadian airmasses are deeper or higher in the atmosphere in most cases and that is what we would want to see for the entire column to be 'cold enough' to support snow. Simple answer, but hope it helps.

So if I pictured a column like one of the ones on my front porch, to support snow very cold air would need to be at the top of that column which would represent the upper atmosphere all the way down to the bottom of that column which would represent the temperature at the ground or the surface? What are these maps being posted showing white, green, blue, with squiggly lines and numbers everywhere? I know they're model maps but what kind of model maps exactly and how can a non-MET like myself understand what all of those numbers mean?

[WacoWx]

THE WEEKEND IS SHAPING UP TO BE PRETTY NICE...ALTHOUGH A LITTLE ON
THE COOL SIDE. HIGHS WILL BE IN THE 40S AND 50S WITH LOWS IN THE
UPPER 20S AND LOWER 30S. ANOTHER SHOT OF COLDER AIR APPEARS LIKELY
TO MOVE INTO NORTH TEXAS EARLY NEXT WEEK. WILL HAVE SOME LOW POPS
IN FOR SUNDAY NIGHT AS THE FRONT SLIDES SOUTHWARD...ALTHOUGH
MOISTURE ONCE AGAIN LOOKS RATHER LIMITED. WILL CONTINUE TO FAVOR
COOLER TEMPS THAN THE MODEL GUIDANCE BASED ON LATEST TRENDS.
LATEST ECMWF RUN IS ALSO INDICATING AN EVEN COLDER SHOT OF AIR
HEADED SOUTH FOR THE LATTER PART OF NEXT WEEK. WILL HAVE TO
MONITOR THIS CLOSELY AS MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT
WITH THE OVERALL SYNOPTIC PATTERN BUT DIFFER ON ON MAGNITUDE OF
COLD AIR INTRUSION.

[gboudx]

Weather update from Steve LaNore, pro-met who worked in DFW area, but now in Tyler.

http://www.examiner.com/x-5182-Dallas-W ... iner-email

[jasons2k]

THE WEEKEND IS SHAPING UP TO BE PRETTY NICE...ALTHOUGH A LITTLE ON
THE COOL SIDE. HIGHS WILL BE IN THE 40S AND 50S WITH LOWS IN THE
UPPER 20S AND LOWER 30S. ANOTHER SHOT OF COLDER AIR APPEARS LIKELY
TO MOVE INTO NORTH TEXAS EARLY NEXT WEEK. WILL HAVE SOME LOW POPS
IN FOR SUNDAY NIGHT AS THE FRONT SLIDES SOUTHWARD...ALTHOUGH
MOISTURE ONCE AGAIN LOOKS RATHER LIMITED. WILL CONTINUE TO FAVOR
COOLER TEMPS THAN THE MODEL GUIDANCE BASED ON LATEST TRENDS.
LATEST ECMWF RUN IS ALSO INDICATING AN EVEN COLDER SHOT OF AIR
HEADED SOUTH FOR THE LATTER PART OF NEXT WEEK. WILL HAVE TO
MONITOR THIS CLOSELY AS MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT
WITH THE OVERALL SYNOPTIC PATTERN BUT DIFFER ON ON MAGNITUDE OF
COLD AIR INTRUSION.

Please cite the source, thank you.

[WacoWx]

^^^

http://forecast.weather.gov/product.php?site=NWS&issuedby=FWD&product=AFD&format=CI&version=1&glossary=1