(New!!) Cold for the Deep South (Models, Maps, Discussion)

[cheezyWXguy]

alrite...I'm gonna lay down my prediction for this weekend icestorm for DFW
Its obvious that this idea will be changed a lot but who doesnt change their predictions or forecasts?
thursday-partly cloudy, high around 70
thursday nite-mostly cloudy, with a slight cance of rain. Lows in the upper 30's
friday-cloudy with a a 30%chance of rain, mixing with freezing rain or very light sleet in the evening. highs in the lower 40's
friday nite-a 40%chance of freezing rain or very light sleet. Lows in the lower 30's
saturday-a 40%chance of sleet and freezing rain. Highs in the mid to upper 30's
saturday nite-mostly cloudy, with a 30%chance of freezing rain or light sleet. lows in the upper 20's
sunday-mostly cloudy with a 30% chance freezing rain, light sleet, or very light snow. highs in lower-mid 30's
sunday night- wintry mix tapreing off around midnite. lows in the upper 20's

[aggiecutter]

The Texarkana area forcast has freezing rain and sleet off and on all weekend. It looks like saturday night and sunday could get real interesting around here.

The arctic air continues to ooz south...

http://www.weatherimages.org/data/imag226.html

[Air Force Met]

Well...after reading the plethera of posts since last night about the blast that wasn't...I think I need to review my 850mb temp lessons again

OK...you cannot base your projected lows on what you see the 850 mb temps doing...radiational cooling or no radiational cooling. First...there could be a massive inversion between the sfc and the 850mb temps...and the sfc temps could be lower (which is common in arctic air before it modifies) or there may not be much of an inversion and the 850 temp may follow the moist or dry adiabate.

So...if you really want to know how cold you are going to get...figure out what your dewpoint is in the lower 50-100mb of the atmosphere is and given radiational cooling...that is how cold you will be. The 850mb temps are a good indicator of how cold the airmass is....but some of you guys are putting way too much stock in them for potential temps. There are too many factors...cloud cover...warm layers...inversions (again...common with arctic air)...lots of things.

Use them as an indicator but PLEASE start referencing some other data to figure out lows other than 850 temps. I might go insane.

[Air Force Met]

The Texarkana area forcast has freezing rain and sleet off and on all weekend. It looks like saturday night and sunday could get real interesting around here.

The arctic air continues to ooz south...

http://www.weatherimages.org/data/imag226.html

Well...right now it's -26F in Hallock, MN...and by your map you can see all the bitterly cold air moving into MN...which shows that the blast is going east....which given the upper flow...is no surprise.

It's not record cold...but it's within 10 degrees or so for this time of year...which is pretty darn chilly.

[Portastorm]

Some of the NWS forecasters in Texas in the last 48 hrs have suggested that this weekend's forecast will be challenging, due to the fact that modeling historically doesn't handle shallow cold airmasses well.

Here is my question: How do we know if the models have a good handle or not on the situation? Will we know by tomorrow at this time? Is the answer as simple as check out the surface temps in Kansas and Oklahoma tomorrow and see how they match with either the GFS or Euro or even the Canadian?

I just wonder what will tip off the pro mets on the developing situation.

[cctxhurricanewatcher]

Some of the NWS forecasters in Texas in the last 48 hrs have suggested that this weekend's forecast will be challenging, due to the fact that modeling historically doesn't handle shallow cold airmasses well.

Here is my question: How do we know if the models have a good handle or not on the situation? Will we know by tomorrow at this time? Is the answer as simple as check out the surface temps in Kansas and Oklahoma tomorrow and see how they match with either the GFS or Euro or even the Canadian?

I just wonder what will tip off the pro mets on the developing situation.

That's been the tone of their AFD's the whole weekend. It's totaly understandable though. When was the last time we really had something like this occur? It's been awhile.

Seems like most of the offices are also on board for a bigger cool down next week.

[Air Force Met]

That's been the tone of their AFD's the whole weekend.

Yeah...and they've covered their bases...like Houston Galveston which was calling for chilly and rainy in the AFD...but going for low 60's and a 30-40% chance of rain in the actual forcast....which really isn't my idea of chilly and rainy.

[cctxhurricanewatcher]

That's been the tone of their AFD's the whole weekend.

Yeah...and they've covered their bases...like Houston Galveston which was calling for chilly and rainy in the AFD...but going for low 60's and a 30-40% chance of rain in the actual forcast....which really isn't my idea of chilly and rainy.

Heck, we get that in April or May with a good rain system.

[aggiecutter]

portastorm, I always keep an eye on Denver, Amarillo, and OKC. If Denver is in the single digits, Amarillo in the mid to upper teens, and OKC near 20, generally the cold air will ooz on down into Texas, atleast the northern half of the state will be below freezing with precipitation. I have seen times when the arctic air would go more south than east and austin-san antonio would be colder than texarkana. Basically, all one can do is wait and see.

[gboudx]

This appears it's gonna be real close for the DFW area. Right now, the NWS has wintry mix forecasted as close as Denton-Decatur-Sherman. I assume we'll know more as today progresses to see how quickly the airmass moves south.

[Johnny]

AFM, at this time, what kind of temperatures would you forecast for Southeast, Texas over the weekend?

I'm seeing the cold front coming through sometime early Friday and once it does temperatures will continue to drop throughout the day and into the night. I think north and central portions of Southeast, Texas will drop into the mid 30's and not stray too far from that on Saturday...possibly lower to mid 40's and maybe a little higher this Sunday.

[Air Force Met]

AFM, at this time, what kind of temperatures would you forecast for Southeast, Texas over the weekend?

I'm seeing the cold front coming through sometime early Friday and once it does temperatures will continue to drop throughout the day and into the night. I think north and central portions of Southeast, Texas will drop into the mid 30's and not stray too far from that on Saturday...possibly lower to mid 40's and maybe a little higher this Sunday.

IMO...that's WAY too cold. I think highs saturday will be in the 50's. Lower 50's if there is more overrunning...and upper 50's if there is less. Take a look at what the NWS is forecasting and lower them by about 5 degrees and that's what I think is going to happen here. I don't think we will see the 30's in the SETX area...especially if there is cloud cover. If it clears...then maybe. The cold air is going to go east and the airmass that will move through us will be highly modified and shallow.

[Johnny]

Gotcha and glad to hear it actually. Now how about next week? Here's a clippet from what Jeff had to say. What do you think? Thanks

Secondary cold surge arrives Tuesday with renewed overrunning precip. This front may drive temps. closer to freezing across SE TX around Wednesday of next week and P-type may become an issue.

[Air Force Met]

Gotcha and glad to hear it actually. Now how about next week? Here's a clippet from what Jeff had to say. What do you think? Thanks

Secondary cold surge arrives Tuesday with renewed overrunning precip. This front may drive temps. closer to freezing across SE TX around Wednesday of next week and P-type may become an issue.

I don't think so. We'll cool down again but this air will also go east. If we do get near freezing it will be for morning lows and nothing more. Gotta wait and see what more model runs bring though.

[Extremeweatherguy]

these thick clouds today were not expected were they?

[Extremeweatherguy]

Latest Houston AFD:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
233 PM CST WED FEB 15 2006

.DISCUSSION...
NOT AN EASY FORECAST PACKAGE THIS AFTERNOON. MAIN PLAYER WILL BE AN
APPROACHING COLD FRONT THAT WILL MOVE SOUTHWARD INTO THE NORTHERN
PORTIONS OF SOUTHEAST TEXAS THURSDAY NIGHT. AHEAD OF THE FRONT
(TONIGHT THROUGH THURSDAY AFTERNOON)...EXPECT A CONTINUATION OF
OUR ABOVE NORMAL TEMPERATURES AND INCREASED CLOUD COVER UNDER A
CAPPED AIRMASS. WEAK DISTURBANCES ALOFT RIDING ACROSS THE AREA ON
A DEVELOPING WEST SOUTHWEST FLOW ALOFT MAY BRING SOME SPRINKLES TO
THE AREA TOO. BETTER RAIN CHANCES BEGIN TO ENTER THE PICTURE
THURSDAY NIGHT AND ON INTO THE WEEKEND AS THE AFOREMENTIONED COLD
FRONT SLOWLY MOVES INTO SOUTHEAST TEXAS AND LINGERS IN THE AREA
(POSSIBLY JUST OFF THE COAST). THIS FOCUSING BOUNDARY IN COMBINATION
WITH DISTURBANCES ALOFT...INCREASING PRECIPITABLE WATER VALUES AND
DEVELOPING ISENTROPIC UPGLIDE WILL BRING PERIODS OF RAIN AND COOLER
TEMPERATURES TO MOST OF SOUTHEAST TEXAS. HAVE CALLED FOR SLIGHTLY
HIGHER RAIN CHANCES AND COOLER TEMPERATURES ACROSS OUR NORTHERN
COUNTIES. THE BREAKDOWN OF MID/UPPER LEVEL RIDGING ALOFT (CENTERED
TO OUR SOUTH OVER THE WEEKEND) EARLY NEXT WEEK SHOULD ALLOW THE FRONT
TO FINALLY MOVE OFF TO OUR SOUTH. THE EXACT TIMING OF THIS SCENARIO
IS IN QUESTION...SO HAVE KEPT RAIN CHANCES IN THE FORECAST ON INTO
NEXT WEEK DUE TO THE EXPECTED CONTINUATION OF ISENTROPIC LIFT. 42

[Extremeweatherguy]

Just to let everybody know. Accuweather.com now has a forecast of 49F for a high in northern Houston on Saturday. I usually do not like the accuweather forecasts past day 5...but since Saturday is only 4 days out, this forecast is more believable. My personal prediction would be that we struggle to reach 50F on Saturday and Sunday of this weekend with a breeze, clouds, and rain. Lows will also only be 5-10F cooler than the highs.

[gboudx]

DFW NWS still forecasting any wintry precip in the N and W zones. Ch 11 met, Mike Burger, just said the same thing; North and West of DFW.

BY 00Z SAT...GOOD AGREEMENT AMONG MODEL PARTIAL THICKNESS VALUES.
GFS PERFECT PROG PARTIAL THICKNESSES REMAIN IN THE RAIN ZONE...
THOUGH MOS OUTPUT STILL SUGGESTS 32F SFC ISOTHERM WILL TEASE THE
METROPLEX. MOS UNAWARE OF LACK OF SNOW PACK...OVERSAMPLING SIMILAR
EVENTS WITH WHICH NORMAL SNOWCOVER LIMITED MODIFICATION. HENCE...
MOS LOW TEMPS MAY BE A FEW DEGREES TOO COLD...WHICH WILL MAKE ALL
THE DIFFERENCE. PERFECT PROG SOUNDINGS SHOWING SFC TEMPS SAFELY
ABOVE FREEZING FROM THE METROPLEX SOUTH AND EAST.

AFTER PREFRONTAL TEMPS IN THE 70S AND 80S...INITIAL WARM NOSE WILL
BE EXTRAORDINARY. ALL PRECIP THROUGH SATURDAY SHOULD REACH THE
GROUND IN LIQUID FORM. SUBFREEZING AIR STILL LIKELY TO ENTER CWA...
LEADING TO -FZRA/FZDZ N AND W ZONES...PARTICULARLY OVERNIGHT AND
MORNING PERIODS. EXPECT FREEZING TEMPS ELSEWHERE TO BE BRIEF AND ICE
ISSUES TO BE LIMITED. QPF STILL APPEARS TO BE LIGHT...BUT ANY ICE
CAN CAUSE PROBLEMS...AND SLIGHT CHANGES TO RESULTING TEMPS COULD
IMPACT TRAVEL BEYOND WHERE FREEZING PRECIPITATION IS CURRENTLY
MENTIONED. CLOUDCOVER AND PRECIP WILL LIMIT DIURNAL RANGE...AND MORE
WIDESPREAD PRECIP OR EVAPORATIVE COOLING WILL REQUIRE HIGHS TO BE
LOWERED. THIS COULD LEAD TO ICE LINGERING LONGER IN COLDEST AREAS.
STILL THINK HIGHS WILL EXCEED FREEZING ALL AREAS...BUT ICE ON GROUND
WITH ONGOING PRECIP AND COLD ADVECTION COULD PROLONG TREACHEROUS
TRAVEL.

SFC COLD ADVECTION WILL BE NEARLY CONTINUOUS WELL INTO NEXT WEEK.
SOME PRECIP SAT NIGHT THROUGH MONDAY MAY BE FROZEN...ICE PELLETS OR
SNOW GRAINS...BUT -FZRA/FZDZ SHOULD STILL BE DOMINANT WINTER PRECIP
TYPE.

STILL APPEARS TO BE ANOTHER PUSH OF CA AIR FILTERING INTO NORTH
TEXAS EARLY NEXT WEEK. A LOT TO HAPPEN BETWEEN NOW AND THEN...BUT
SIGNIFICANT MODERATING OF THE SFC LAYER WILL BE DELAYED. HIGH TEMPS
NORTHERN HALF MAY MAY FAIL TO REACH 50 DEGREES...UNTIL WEDNESDAY.

[cheezyWXguy]

didnt u read plainsman's post in the "plains snowstorm thursday nite" topic when he said to ignore the part that says "N and W counties and suburbs only"?

[cheezyWXguy]

In my opinion...and so i hear, the NWS is being very consevative with this front...2 days ago, abc met troy dungan(or duncan, however u spell it) said that the temps may haf to be forecasted lower than mentioned at the time and it looks like that will still be the case...TWC seems to be onboard for the event as well, with highs in the mid to upper 30's on sunday with a lite wintry mix