Texas winter wx thread (2009-2010)

[srainhoutx]

Found this little nugget in the Amarillo morning Disco...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
354 AM CST FRI NOV 27 2009


.DISCUSSION...
THE SUBTROPICAL MOISTURE STREAM ASSOCIATED WITH THE WAVE MOVING
ACROSS CHIHUAHUA HAS RESULTED IN INCREASING HIGH LEVEL CLOUDS ACROSS
THE AREA DESPITE THE SUBSIDENCE FROM THE MID LEVEL ANTICYCLONE. AT
THE SURFACE...SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH. THE
RESULTANT DOWNSLOPE CONDITIONS SHOULD SUPPORT TEMPS REACHING THE
LOWER 70S ACROSS MUCH OF THE AREA. THE INCREASING HIGH CLOUDS SHOULD
BE THE ONLY FEATURE THAT PROHIBITS TEMPS FROM WARMING MUCH MORE THAN
THE FORECAST CURRENTLY DEPICTS. ON SATURDAY...THE FIRST COLD FRONT
WILL ARRIVE...DIPPING AS FAR SOUTH AS THE CANADIAN RIVER VALLEY BY
MIDDAY. TEMPS AHEAD OF THE FRONT SHOULD AGAIN WARM INTO THE UPPER
60S AND LOWER 70S...WITH UPPER 50S AND LOWER 60S ACROSS THE NORTH.

SATURDAY NIGHT IS WHEN THE FORECAST BECOMES MORE COMPLICATED. THE
SHORTWAVE CURRENTLY MOVING INTO THE PACNW WILL DIVE TO THE SOUTH
SOUTHEAST...CUTTING OFF OVER SOCAL THROUGH THE WEEKEND. THE NORTHERN
STREAM TROF WILL RAPIDLY MOVE ACROSS THE CENTRAL PLAINS. BETWEEN
THESE FEATURES...MODEST MID LEVEL FRONTOGENESIS...SUPER IMPOSED WITH
NEGATIVE EPV VALUES WILL LIKELY SUPPORT SOME LIGHT TO MODERATE
PRECIP BANDS LATE SATURDAY NIGHT INTO SUNDAY MORNING. ALOFT...AN H25
JET WILL MOVE INTO PLACE TO OUR SOUTHWEST...GIVING THE PANHANDLES A
BRIEF WINDOW OF ENHANCED VERTICAL MOTION. THE PRECIP IS FORECAST TO
CHANGE OVER TO SNOW DURING THE DAY AS THE COLDER AIR DEEPENS.
FORECAST SNOW TOTALS GENERALLY FALL IN THE 1 TO 2 INCH RANGE ACROSS
THE NORTHWEST HALF OF THE CWA...WITH TOTALS UNDER AN INCH IN THE
SOUTHEAST HALF. SNOW SHOULD END QUICKLY SUNDAY EVENING AS MID LEVEL
FRONTOLYSIS DEVELOPS.

MONDAY WILL REMAIN ON THE COOL SIDE. THE LOW CLOUDS ARE EXPECTED TO
BREAK ALLOWING TEMPS TO WARM INTO THE MID/UPPER 40S. WARMER TEMPS
ARE EXPECTED ON TUESDAY AS SOUTHWEST WINDS RETURN...BUT THIS SHOULD
BE SHORT LIVED AS THE NEXT COLD AIRMASS MARCHES SOUTH. THE
OPERATIONAL GFS IS THE OUTLIER OF THE LATEST SUITE OF MEDIUM RANGE
MODELS. IT TAKES THE NEXT WAVE OF COLD AIR AND MOVES IT TO THE EAST
ACROSS THE GREAT LAKES. THE CANADIAN...ECMWF AND UKMET SHOW A
PATTERN RESEMBLES A MCFARLAND SIGNATURE...WHICH WOULD SIGNIFY AN
IMPENDING COLD AIR DUMP. WE HAVE OPTED TO GO MORE ALONG WITH THE
ECMWF FORECAST AND HAVE IGNORED THE 00Z GFS AS IT STILL EXHIBITS
CONSIDERABLE DIFFERENCES AMONG ITS ENSEMBLE MEMBERS. FORECAST TEMPS
FOR THURSDAY AND FRIDAY CURRENTLY HOVER AROUND 40 DEGREES...BUT THIS
MAY BE TOO WARM IF THE PATTERN VERIFIES.

THANKS TO DDC...ABQ...PUB AND LUB FOR THE COORDINATION.

[Portastorm]

Some early morning post-Thanksgiving thoughts from Portastorm:

1) NWSFO New Braunfels has dropped their forecasted high temps for early next week for Austin from the lower 60s to the mid 40s in the last 36 hours. Hmmm. This seems to happen every year.

2) The Euro and the Canadian both show the upper low crossing my part of Texas early next week which would mean an early December Snow Miracle for Bevo and his friends. The GFS does not. Looks like a challenging forecast period for our gooberment-paid weather forecasters.

3) Amarillo is using the words "McFarland Signature"??!!! Yikes!

4) OT but ... geez am I ever relieved the Horns didn't have to give the football back to Jerrod Johnson. That guy is a stud. Aggie fans should feel excited about their future with that guy at QB.

[srainhoutx]

HPC Prelim Disco offer some "hints" concerning our 1st and 2nd events. What an interesting week ahead for those that look forward to wintry weather in TX...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
859 AM EST FRI NOV 27 2009

VALID 12Z TUE DEC 01 2009 - 12Z FRI DEC 04 2009


UPDATED PRELIM PROGS SUBSTITUTED THE NEW 00Z/27 ECMWF ENSEMBLE
MEAN FOR THE OLDER 12Z/26 ECMWF MEAN USED IN THE EARLIER
BLEND....AND ELIMINATED THE DETERMINISTIC 12Z/26 ECMWF AS PART OF
THE MIX. THE 00Z/27 DETERMINISTIC ECMWF DID NOT SEEM TO BE IN
SERIOUS DISAGREEMENT WITH THE CORRESPONDING 12Z RUN. AND DETAIL
DIFFERENCES IN THE ECMWF SHORTWAVE DROPPING INTO THE NRN ROCKIES
TUE DAY 4 SEEM TO WORK THEMSELVES OUT WED-FRI DAYS 5-7 WITH
PREVIOUS 12Z CONTINUITY. ALSO...THE NEW 00Z/27 ECMWF MEAN WAS
COMPATIBLE WITH THE OLDER 12Z/26 ECMWF MEAN ON ALL THE MAIN
WEATHER FEATURES.

A MID LVL TROF EXTENDING FROM THE GRTLKS INTO THE PLAINS AS OF DAY
3 MON SHOULD CONTINUE NEWD...WHILE UPSTREAM NRN STREAM ENERGY
POISED TO ENTER WRN NOAM IS FCST TO AMPLIFY INTO THE CNTRL CONUS
BY MID-LATE WEEK. THIS DEEPENING NRN STREAM TROF WILL USHER
RATHER COLD AIR INTO THE ROCKIES/PLAINS...AND HELP TO EJECT A SRN
STREAM UPR LOW THAT SHOULD INITIALLY BE OVER EXTREME NRN MEXICO.
ONE OR MORE PIECES OF ERN PAC ENERGY MAY FLOW AROUND OR THRU A
MEAN RIDGE OVER THE ERN PAC.

HAVING DECIDED IN THE EARLY PRELIM TO DISPENSE WITH THE
DETERMINISTIC GFS...WE STAYED BASICALLY WITH A 00Z/27
DETERMINISTIC ECMWF/ECMWF ENSEMBLE MEAN SCENARIO. THE 06Z/27
DETERMINISTIC GFS CONTINUED THE APPARENTLY ERRONEOUS THEME OF THE
CORRESPONDING 00Z/27 RUN OF SHOWING MINIMAL INTERACTION BETWEEN
THE SRN STREAM AND THE POLAR BRANCH OF THE WESTERLIES.

THERE IS STILL A DECENT SPREAD WITH THE SYSTEM EJECTING FROM NRN
MEXICO. ENSEMBLE SPAGHETTI PLOTS SHOW THE ECMWF RUNS ARE ON THE
SLOWER SIDE OF THE SPECTRUM....BUT WE WILL AWAIT FUTURE GUIDANCE
BEFORE ADJUSTING FROM THE ECMWF HERE IN LIGHT OF ITS PREFERRED
HANDLING OF FLOW ELSEWHERE. ALSO...WE WILL BE WATCHING ANOTHER
AREA OF RELATIVELY HIGH SPREAD DEVELOPING OVER THE SWRN STATES THE
LATTER PORTION OF MEXT WEEK FROM YET ANOTHER SRN STREAM SYS.
RAUSCH/FLOOD

[wxman22]

yea it is incorrigible that the Euro has the cold core crossing right over central texas and then into southeast texas...

[Tireman4]

4) OT but ... geez am I ever relieved the Horns didn't have to give the football back to Jerrod Johnson. That guy is a stud. Aggie fans should feel excited about their future with that guy at QB.[/quote]


Yeah, another OT is that Jerrod Johnson graduated from Humble High School ( the high school is right down the street from me). He is really an all around great guy ( there was a write up on he and his family not too long ago).

[snow and ice]

Texarkana is not going to have a freeze this month. If this has ever happened in my lifetime, I can't remember it. The average date for the first freeze in Texarkana is around the second week of November. Needless to say, we are way past due.

The EURO and the Ensembles are in good agreement in the long range as far as the cold. Both have a very cold look with a west coast ridge and and central-southern trough.

http://www.ecmwf.int/products/forecasts ... 9112700!!/

http://www.meteo.psu.edu/~gadomski/ENSH ... /f240.html

[srainhoutx]

I will add that parts of Far W TX look to get some robust snow total if trend continues. El Paso continues to beef up their forecast for the first storm...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM
513 AM MST FRI NOV 27 2009

.SYNOPSIS...
A MINOR DISTURBANCE ALOFT HAS SPREAD SOME MID AND HIGH LEVEL
CLOUDINESS ACROSS THE SOUTHERN FRINGES OF THE BORDERLAND...OTHERWISE
ANOTHER MILD DAY IS IN STORE FOR OUR AREA WITH FRIDAY`S AFTERNOON
TEMPERATURES RISING TO ABOVE SEASONAL VALUES FOR THIS TIME OF
YEAR. THIS WILL BE THE LAST GOOD WEATHER DAY FOR THE BORDERLAND AS
A SIGNIFICANT WINTER STORM IS FORECAST TO MOVE INTO THE REGION
BEGINNING WITH RAIN SHOWERS MOVING INTO THE GILA WILDERNESS ON
SATURDAY WITH SHOWERS SPREADING EASTWARD ON SUNDAY COVERING THE
ENTIRE REGION BY MONDAY INTO TUESDAY MORNING. A COLD CLOSED LOW
ALOFT OVER THE BAJA AREA WILL START TO SPREAD CONSIDERABLE
MOISTURE EASTWARD AND EVENTUALLY OVERRUN MUCH COLDER POLAR AIR AT
THE SURFACE WHICH WILL BE BROUGHT INTO THE REGION BY A BACKDOOR
COLD FRONT LATER SUNDAY. HEAVY MOUNTAIN SNOWS ARE LIKELY WITH RAIN
SHOWERS CHANGING TO SNOW SHOWERS AT LOWER ELEVATIONS BY MONDAY
AFTERNOON AND CONTINUING INTO EARLY TUESDAY MORNING WITH
ACCUMULATIONS POSSIBLE IN THE LOWLANDS. LISTEN FOR FURTHER
INFORMATION ON NOAA WEATHER RADIO AND THE LOCAL MEDIA FOR UPDATES
TO THIS DEVELOPING STORM.

[iorange55]

I've noticed it looks really strong over west Texas, and then when it moves across Texas the Area is just as broad, but the amount of precip goes down considerably, is that normal? Or do you think the models are just not handling it right?

[srainhoutx]

A quick look at the 12Z NAM suggest a rather robust cutoff Upper Low developing over the Baja and moving slowly ESE into Northern MX. This feature is currently near the N CA coast and will be sampled with upper air data now. We shall see what that data will offer RE: future guidance. Concerning moisture, it will depend on the STJ. That will be the feed in the mid/upper levels intially for the Upper Low. With upper air data entered into future guidance output, should see a better picture of the possible future QPF across TX. Keep an eye on a surface low developing behind the front dragging down colder air at the surface. This surface low may develop near the coast in the NW GOM. The Upper Low will move in slowly behind the developing surface low creating an strong over running event. The pattern looks to be a 2 day event IMHO.

[wxman22]

Not gonna get excited yet ofcourse, but this setup looks so similar to last years surprise snow that its hard not to be optimistic, i guess will see...

[Portastorm]

I've noticed it looks really strong over west Texas, and then when it moves across Texas the Area is just as broad, but the amount of precip goes down considerably, is that normal? Or do you think the models are just not handling it right?

Well, srainhoutx did a nice job of laying out some of the factors at play ... but the amount of moisture that the upper low will have to work with is going to depend on whether or not a surface low really develops in the NW Gulf. If it does, then it comes down to timing. But generally speaking, the surface low in the Gulf would cut off moisture inflow from the Gulf to the upper low.

[iorange55]

I've noticed it looks really strong over west Texas, and then when it moves across Texas the Area is just as broad, but the amount of precip goes down considerably, is that normal? Or do you think the models are just not handling it right?

Well, srainhoutx did a nice job of laying out some of the factors at play ... but the amount of moisture that the upper low will have to work with is going to depend on whether or not a surface low really develops in the NW Gulf. If it does, then it comes down to timing. But generally speaking, the surface low in the Gulf would cut off moisture inflow from the Gulf to the upper low.

Duh that was rather obvious I'm not sure why it didn't click.



The GFS 12 looks like in the long range it's starting to trend colder more in line with the euro.

[Portastorm]

Yeah, iorange55, I noticed that as well. You know, I'm really not worked up yet about the possibility of wintry weather in my part of Texas next week. These upper lows are so difficult to forecast that anything this far out cannot be too reliable. I've seen so many times where we (AUS) were forecasted to net something exciting out of an upper low and it didn't materialize for a variety of reasons (track of the low changed ... upper low sheared out ... upper low had less moisture than progged to work with, etc.).

This Charlie Brown has not laced up his kicking shoes just yet! However, I do think it is a good bet that our weather will turn colder and wetter in the next two weeks. I think we all can be confident in that!

[richtrav]

For the most part its true, that the artic blasts have been milder, but an event that sticks out in my mind is the 2004 storm when places like victoria texas got 13 inches of snow. Hell, even brownsville got 2.Sure it wasnt rididculously cold, but it was enough to drop a ton of snow by texas standards. Thats really all I wish for is the snow, not the incredibly frigid air...just enough to keep us below freezing long enough for me to get some good snow and a day or two off of school.
Frankly, I could care less about breaking temperature records

Oh yeah, that event was amazing, I was in SA at the time and thought my friends down in Harlingen were crazy when they said it was snowing, I figured it was just a couple of flurries (we didn't get a bit in SA). But sure enough, they were having their first snow since 1895. The most unusual part about it was that it managed to freeze as far south as the El Cielo and Aldama region in Tamaulipas judging from the frosted back trees in those areas while Texas was just in a fairly generic cold spell outside the southern part of the state. I have seen that once before, in Dec 1997, when it stayed above freezing in S Texas but brought a harsh cold snap and snow WAY down into Mexico, as far south as the Guadalajara area, and temps in the teens in San Luis Potosi. Really weird, you would think it would have to get very cold in TX or NM for it to reach the Mexican Plateau (as it did in '62) but apparently not

[Portastorm]

The 12z Euro run takes the upper low a little further north in its travel across Texas early next week. As said by myself and others here, I suspect the actual track may shift around a bit in the next 24-36 hours by the modeling. But if the 12z Euro run were to verify, I would think folks in the Big Bend area to San Angelo to Waco to Lufkin/Tyler might get early December snow fun. Just cold rain here in Austin.

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/ecmwfloop.html

[srainhoutx]

The 00Z NAM is running. We should see the first Upper Air samples of this system in the run now that it is onshore in CA.

[gofrogs]

WOOOOOOOOOOOOOOOOOW did you see the 18z gfs run in the ten to sixteen day run for dfw.

[zaqxsw75050]

Yeah... if the forecast verify (which I don't think it will happen) it would be a disaster... However, I think it is a good sign for us to see some wintry precip in the long range.

[srainhoutx]

The interetsing thing to watch is the trend to an active period across TX. Sure appears that we will see the snow cover increase to our N that will aid in less modified air masses as we move forward. Remember that we are not really into the wintry weather prime time for us in TX that usually starts taking shape in the mid December through February time frame. If this pattern persist, we will likely have plenty to discuss in the days and weeks ahead with the current El Nino Pattern.

[serenata09]

Can someone post a link to the 10-16 day?