February 1-5, 2011 Arctic Blast/Winter Storm Discussion

[tireman4]

Wxman57. Did you see Air Force Met's numbers for accumulation on Storm 2k?

[Rich]

wxman57, thanks for all your input and analysis regarding this upcoming event. When you give your insight on upcoming events I know we are all listening. (even if we are sometimes in wish-casting mode) you bring us to reality. I feel alot more confident in the upcoming event knowing you are onboard.

[TexasMetBlake]

<tapping foot...deep breathes...saying, geez, come on with it already! Gimme the zones!>

[Rich]

<tapping foot...deep breathes...saying, geez, come on with it already! Gimme the zones!>

I know right! I must of refreshed the HGX webpage a 100 times lol

[TexasMetBlake]

Dallas: WOW


[b]LOOKING AT THE FORECAST TEMPERATURES AND GOING THROUGH THE CLIMO
DATA IT IS APPARENT THAT THIS COLD SNAP WILL BE THE COLDEST SINCE
THE INFAMOUS DEC 1989 EVENT. FOR SOME DFW RECORD INFO SEE PNSDFW.[/b]

CONVECTIVE CUMULUS CLOUDS THIS AFTERNOON HAVE CONTAINED SOME WEAK
SNOW SHOWERS...BUT THIS ACTIVITY WILL END WITH SUNSET. WINTER
STORM WARNINGS/ADVISORIES WILL EXPIRE...BUT THE REGIONS THAT
WERE HIT HARD WITH SLEET AND SNOW WILL HAVE ICY AND SNOW/SLEET
PACKED ROADS FOR QUITE SOME TIME. TEMPERATURES WILL REMAIN WELL
BELOW FREEZING AND LIMITED SUNSHINE IS EXPECTED OVER THE NEXT FEW
DAYS TO HELP WITH MELTING.

THE CUMULIFORM CLOUD COVER SHOULD DISPERSE THIS EVENING. THE CLEAR
SKIES AND CONTINUED STRONG COLD ADVECTION /WITH CURRENT TEMPS IN
THE SINGLE DIGITS ACROSS WESTERN OKLAHOMA/ WILL CAUSE OUR TEMPS TO
DROP SEVERAL DEGREES AFTER SUNSET. SNOW PACK EXTENDS ACROSS THE
ENTIRE PLAINS TO THE DFW DOORSTEP AND LIMITED MODIFICATION OF THIS
ARCTIC AIR IS EXPECTED. HAVE UNDERCUT GUIDANCE TONIGHT BUT BELIEVE
THE ARRIVAL OF MID CLOUDS AFTER MIDNIGHT WILL HELP US OUT. A HARD
FREEZE WARNING HAS BEEN ISSUED DUE TO THE PROLONGED DURATION OF
SINGLE DIGIT AND TEEN TEMPERATURES. USUALLY WHEN WE GET TEMPS THIS
COLD IT IS ON A NIGHT OF RADIATIONAL COOLING AND IS SHORT LIVED.
WE ANTICIPATE ISSUES WITH FROZEN/BURST PIPES AND ALSO NON-NATIVE
VEGETATION NOT HARDY ENOUGH FOR THE RARE BUT EXTREME COLD TEXAS
WEATHER PRESENTS. WINDS SHOULD SUBSIDE BELOW ADVISORY CRITERIA
AROUND SUNSET BUT REMAIN BREEZY THROUGH TONIGHT. WIND CHILLS WILL
CONTINUE BELOW 0 AND WIND CHILL ADVISORY HAS BEEN EXTENDED
THROUGH 10 AM WEDNESDAY BUT WILL LIKELY BE EXTENDED FURTHER.

LOW-MID LEVEL MOISTURE INCREASES TOMORROW OVER THE NW HALF OF THE
CWA IN ASSOCIATION WITH A MID LEVEL WAVE. EXPECT ENOUGH LIFT AND
MOISTURE FOR SOME SNOW...BUT LOW LEVELS WILL LIKELY BE TOO DRY TO
CAUSE MUCH ACCUMULATION. WILL CARRY SNOW FLURRIES ACROSS THE NW
HALF OF THE CWA. HIGHS WILL REMAIN VERY COLD TOMORROW AS NORTH
WINDS AND MODEST COLD ADVECTION CONTINUE. MORE CLOUDS ARE EXPECTED
TOMORROW NIGHT AND WENT WITH LOWS NEAR TONIGHT/S FORECAST. MAV MOS
IS SEVERAL DEGREES COLDER THAN PERFECT PROG MODEL VALUES BUT MOS
IS LACKING A STATISTICAL FOUNDATION SINCE IT HAS NEVER SEEN VALUES
LIKE THIS BEFORE HERE. WINDS WILL BEGIN TO SUBSIDE THURSDAY BUT
CLOUD COVER OUT AHEAD OF AN UPPER LEVEL LOW SWINGING THROUGH THE
BIG BEND WILL KEEP THE MODERATION OF TEMPS SLOW.

THIS UPPER LOW PRESENTS A FORECAST CHALLENGE IN THAT THE 500 MB
PATTERN IS A VERY FAVORABLE ONE CLIMATOLOGICALLY FOR SIGNIFICANT
SNOWFALL IN TEXAS. MODELS CONTINUE TO SUGGEST MOISTURE WILL BE
LACKING...LIKELY DUE TO THE STRENGTH/DEPTH OF THE DRY ARCTIC AIR
MASS IN PLACE. HOWEVER...STILL BELIEVE MODELS ARE UNDERESTIMATING
THE AMOUNT MOISTURE THIS SYSTEM WILL BE ABLE TO BRING UP FROM THE
GULF. ON THE OTHER HAND THE ABSENCE OF A NEARBY BAROCLINIC ZONE
SHOULD KEEP THIS FEATURE FROM INTENSIFYING. GFS ENSEMBLE AND SREF
MEMBERS ARE UNANIMOUSLY MORE AGGRESSIVE WITH THE SNOW FORECAST AND
ABOUT 3/4 OF THEM PUT 1-2 INCHES OF SNOW ACROSS OUR SOUTHERN AND
SOUTHEAST COUNTIES. THIS IS A LITTLE HIGHER THAN I AM COMFORTABLE
FORECASTING AS I WOULD LIKE TO SEE EITHER THE OPERATIONAL ECMWF OR
GFS SOLUTION LOOK SIMILAR. BUT WE SHOW POPS FOR LIGHT SNOW ACROSS
THE SOUTHEAST HALF OF THE CWA THURSDAY NIGHT AND FRIDAY...AND KEEP
ACCUM LESS THAN 1 INCH...WITH HIGHER AMOUNTS LIKELY FARTHER
SOUTH CLOSER TO GULF MOISTURE. CLOUDS FROM THE UPPER LOW PASSING
OVER MAY EXTEND THE SUBFREEZING STREAK UNTIL SATURDAY.

THANKFULLY WESTERLY WINDS BEHIND THIS SYSTEM WILL BRING WARMER
WEATHER THIS WEEKEND. LINGERING SNOW PACK OVER THE W/NW WILL
TEMPER WARM UP MORE THAN MODELS RECOGNIZE SATURDAY...BUT HIGHS IN
THE 50S AND LOWS IN THE 30S ARE EXPECTED BY SUPERBOWL SUNDAY.
MODELS ARE INDICATING ANOTHER ARCTIC FRONT EARLY MONDAY OR LATE
TUESDAY...BUT WILL BLEND SOLUTIONS AND GO WITH MONDAY
AFTERNOON...DUE TO 500 MB PATTERN DISAGREEMENTS. NO UPPER LEVEL
SHORTWAVE COMES IN TANDEM WITH THIS FRONT AND ANY PRECIP WOULD BE
BRIEF AND LIGHT.

TR.92

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 8 21 8 23 13 / 5 10 10 10 10
WACO, TX 12 27 11 26 15 / 5 10 10 10 30
PARIS, TX 9 23 9 27 11 / 5 10 10 10 10
DENTON, TX 6 19 7 22 9 / 5 10 10 10 10
MCKINNEY, TX 9 21 8 25 9 / 5 10 10 10 10
DALLAS, TX 9 21 9 24 14 / 5 10 10 10 20
TERRELL, TX 11 23 8 27 12 / 5 10 10 10 20
CORSICANA, TX 13 25 12 27 16 / 5 10 10 10 30
TEMPLE, TX 12 27 11 25 15 / 5 10 10 10 30
MINERAL WELLS, TX 6 19 6 22 11 / 5 10 10 10 10

[Ptarmigan]

Yes, next Tue-Wed may be an even bigger (stronger) cold air outbreak, but a dry one that covers all the southern U.S. Euro has the 1050+ high dropping straight south to the lower Valley next week and the 850mb freezing line almost down to the Yucatan and NE to Miami.

Another freeze next week? I checked GFS and showed it would not be as cold as this one. It is too early to tell at this point.

[TexasMetBlake]

Houston:

COLD WX HAS ARRIVED AND WILL PERSIST INTO THE FIRST PARTS OF THE
WEEKEND. HAVE GENERALLY FOLLOWED (AND MANY TIMES UNDERCUT) LOWEST
ENSEMBLE MOS SUGGESTIONS REGARDING TEMPS. HARD FREEZE WARNING WILL
OBVIOUSLY CONTINUE AND WILL NEED TO BE EXTENDED EACH NIGHT UNTIL
FRI MORNING. WIND CHILL ADVSY WILL BE ISSUED TONIGHT FOR WNW & NRN
COUNTIES TONIGHT WITH WIND CHILL VALUES FCST TO DIP SLIGHTLY BELOW
ZERO. WILL PROBABLY SEE SOME PERIODS OF SUN ON WED BUT WITH THE
COLD START AND ONGOING CAA DOUBT WE`LL SEE READINGS GET OUT OF THE
30S AND POSSIBLY NOT ABOVE FREEZING AT ALL NORTH.

EXPECT MOISTURE TO BEGIN OVERRUNNING THE COLD AIR AT THE SFC ON
THURS. STILL ANTICIPATING A WINTER WX EVENT BEGINNING AS EARLY AS
LATE AFTN THURS NEAR THE COAST AS SOUNDINGS BECOME INCREASINGLY
SATURATED...BUT MOSTLY DURING THE OVERNIGHT HOURS THURSDAY NIGHT
AND FRIDAY MORNING. MODELS CONTINUING TO SHOW TROF DROPPING INTO
MEXICO THURS THEN EJECTING INTO TX DURING THE OVERNIGHT HOURS.
SOME DISCREPANCY AS TO WHAT THE TEMP PROFILE BETWEEN MODELS THURS
EVENING AND WOULDN`T BE SURPRISED TO SEE PRECIP START OUT AS A MIX
NEAR THE GALVESTON BAY REGION BEFORE CONVERTING OVER TO SNOW. HAVE
SHIFTED THE HIGHER CHANCES EVEN FURTHER INLAND AND ALSO TWEAKED
ACCUMS UP INTO THE 1-3" RANGE. AM GETTING CONCERNED ABOUT AMOUNTS
THOUGH AND AT THIS POINT WOULDN`T BE SURPRISED TO SEE EVEN HIGHER
AMOUNTS IN BANDING WHERE EVER IT SETS UP. CANADIAN MODEL WILL NOT
BACK DOWN ON ACCUMS AND THIS RUN ACTUALLY SHOWS COLDER H85 TEMPS.
LOOKED AT MOST OF THE OTHER MODELS FCST SOUNDINGS AND THEY APPEARED
FAIRLY IMPRESSIVE AT TIMES AND KINDA WONDER WHY SOME DEPICT SUCH
LOW QPFS. WILL REALLY NEED TO WATCH THIS.

AT THIS POINT...IT`S IMPORTANT TO UNDERSTAND THE FCST IS SUSCEPTIBLE
TO SUBSTANTIAL QPF CHANGES...TYPE AND WHERE THE HIGHER AMOUNT
WILL OCCUR. ALTHOUGH THE HIGHEST AVAIL MOISTURE IS NEAREST THE
COAST AND SE AREAS...THE UPPER LOW/VORT LOOKS LIKE IT`LL TAKE A
MORE NRLY TRACK THAN WE SAW XMAS EVE 2004 HENCE TOOK THE HIGHER
AMOUNTS A LITTLE FURTHER N THAN PREVIOUS FCST.

BRIEF "WARMUP" OVER THE WEEKEND FOLLOWED BY ANOTHER ARCTIC FRONT
MON (GFS) OR TUE (ECMWF). 47

[wxman57]

Yes, next Tue-Wed may be an even bigger (stronger) cold air outbreak, but a dry one that covers all the southern U.S. Euro has the 1050+ high dropping straight south to the lower Valley next week and the 850mb freezing line almost down to the Yucatan and NE to Miami.

Another freeze next week? I checked GFS and showed it would not be as cold as this one. It is too early to tell at this point.

Check the Euro. Much colder air next Wed/Thu than this week, at least aloft. 850mb freeze line nearly down to the Yucatan and extending east to Miami next Thursday. 1057 high dropping straight south to Texas. Much larger outbreak extending all the way to Florida.

[TexasMetBlake]

14 in CLL tonight!!!!

19 at IAH!

[wxman57]

It would make sense that the core of the upper low passing a bit farther north might increase snow amounts farther north, but there will still be a good bit of moisture along the coast. Maybe everyone will share in the snow Friday?

[Mr. T]

HGX goes with 19 tonight for IAH and 14 for CLL

[Mr. T]

Tonight...Partly cloudy. Breezy. Much colder. Lows around 19. North winds 15 to 25 mph. Wind chill readings 2 to 12.

Wednesday...Partly cloudy. Colder. Highs in the mid 30s. North winds 10 to 15 mph. Lowest wind chill readings 2 to 12 in the morning.

Wednesday Night...Partly cloudy. Lows in the lower 20s. North winds 10 to 15 mph.

Thursday...Mostly cloudy. A 20 percent chance of flurries late in the afternoon. Little or no snow accumulation. Highs in the mid 30s. North winds 10 to 15 mph. Lowest wind chill readings 4 to 14 in the morning.

Thursday Night...Snow and sleet likely in the evening...then snow likely after midnight. Snow and sleet accumulation of 1 to 2 inches. Ice accumulation of less than one tenth of an inch. Lows in the mid 20s. North winds 5 to 10 mph. Chance of precipitation 60 percent.

Friday...Cloudy. Snow likely in the morning...then a chance of snow in the afternoon. Snow accumulation around 1 inch. Highs in the mid 30s. Chance of precipitation 60 percent in the morning decreasing to 30 percent in the afternoon.

Friday Night...Partly cloudy in the evening then clearing. Lows in the mid 20s.



Harris Zone!

[Rich]

orangeblood wrote:
It appears this upper low won't dig as far south thus causing less moisture to be pulled up from the gulf. If you want a 2004 storm, that storm needs to dig much further south.

From Air Force Met on Storm2K

That is incorrect.

The 2004 storm had the 300 DM line down just to the Red River of TX/OK. It ran from about a Perryton-CD-SPS-TXK line. The 320 DM line ran from the extreme corner of SE NM to about 50 miles N of Del Rio to Longview. The 330 line was down into Mex.

This storm has the 300 DM line along the west Tx/E NM borde - to the big bend of TX...south of Del Rio - to CLL to GGG. The 320 line is ovr west tx...into Mex...to Houston.

Another diff is the 700Mb moisture. The 2004 storm had the 90% RH's (precip threshold) just along the coast...this system has 90% over the eastern 1/3 of TX.

This is a stronger shotwave than 2004 (for example...heights over San Angelo will be 45 meters LOWER in this system than 2004)...it diggs much further south...and there is much more moisture progged.

[srainhoutx]

It would make sense that the core of the upper low passing a bit farther north might increase snow amounts farther north, but there will still be a good bit of moisture along the coast. Maybe everyone will share in the snow Friday?

That northerly trend started showing up night before last in some of the guidance. It raised an eyebrow and certainly the trends over the last 24 hours would agree we may all share in some form or fashion with this event. Hopefully it will verify, now that everyone's ears are perked.

[wxman57]

18Z NAM meteogram. About 0.3" moisture. Could equate to about 3" snow:

[srainhoutx]

18Z GFS suggests more moisture. That model is trending much wetter(snow) across most, if not all of Central/SE TX and points E.

[harpman]

We have gone from a cold rain to a possible sleet event here in s.e. La. See the progression??

[Ptarmigan]

HGX goes with 19 tonight for IAH and 14 for CLL

That would be the first since January 1996.

[Paul]

18Z seems a lot wetter....similar to the CMC....if you aint jumping on yet BiggerByte your going to be left behind....

[weatherfreak]

I check this forum all of the time...but never post! I just wanted to thank everyone for all of the great information! I am finally starting to get excited and hoping for a SNOW DAY on Friday!