Texas winter wx thread (2009-2010)

[Ntxw]

Latest out of FW AFD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
913 PM CST SAT DEC 26 2009

.UPDATE...
HAVE MADE SOME CHANGES TO SKY CONDITIONS AND TEMPS FOR TONIGHT.
OTHER MINOR MAX/MIN ADJUSTMENTS MADE MONDAY THROUGH THURSDAY.

TONIGHTS NAM AND THIS MORNINGS GFS AND ECMWF CONTINUE TO DEPICT
INCREASING MOISTURE MONDAY INTO TUESDAY FROM THE SOUTHWEST AS
UPPER TROUGH APPROACHES. CURRENTLY...FORECAST SOUNDINGS ARE COLDER
ENOUGH FOR MOSTLY SNOW TUESDAY OVER THE NORTHWEST HALF... AND A
WINTRY MIX ELSEWHERE. AS WE MOVE INTO TUESDAY NIGHT...THE LOWER
ATMOSPHERE WARMS ABOVE FREEZING OVER THE SOUTH...RESULTING IN A
TRANSITION TO ALL RAIN. WINTRY MIX CONTINUES OVER THE NORTH. AS
NEW MODEL INFORMATION ROLLS IN OVER THE NEXT 48 HOURS...WE WILL BE
RE-EVALUATING THE TEMPERATURE STRUCTURE UP TO 15000 FEET TO
DETERMINE WHERE THE DIVIDING LINE BETWEEN LIQUID AND A MIX WILL
BE. 75

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.


looks to me like a snow event nw sections of n.tx and a winter precip including poss frz rain across the metroplex region... this is subject to change...

edit: looks like fws is thinkin the same thing, i would just say iam still slightly more worried about a frz rain event w/this upcoming system but we will see..

[HockeyTx82]

Do the computer models take into account snow pack when they spit out temps? There is a bunch of snow pack from Texas all they way up to Canada now. Just curious.......

[Ntxw]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.


looks to me like a snow event nw sections of n.tx and a winter precip including poss frz rain across the metroplex region... this is subject to change...

edit: looks like fws is thinkin the same thing, i would just say iam still slightly more worried about a frz rain event w/this upcoming system but we will see..

Just my personal opinion on this knowledge, but wouldn't freezing rain be cold shallow air undercutting warm air above? This event seems rather the opposite. Colder up throughout the column and the lowest levels warm which would prevent anything like freezing rain. Any thoughts?

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

you make a good point, iam not saying its not gonna be total snow just saying i was not
TOTALLY confident but we will see.. although quite frankly looking @ the latest data
more likely then not it is favoring snow

[Ntxw]

Do the computer models take into account snow pack when they spit out temps? There is a bunch of snow pack from Texas all they way up to Canada now. Just curious.......

I don't believe they do.

New gfs looks to be a bit colder than 12z.

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

gfs i believe trys pushing the system out way to quick... but we will see also
yes for most of the peroid this seems to favor a snow event v.s. anything else.. after
taking abit more time to look @ this i would think any of the 'winter mix' bag event
would poss be even further s,e of the metroplex but as of rightnow the snow event
looks to include the dallas-fortworth metroplex.

[gofrogs]

Whats the new gfs saying as it is running right know i believe and for the later new years eve time frame as the gfs lost that storm but has brought it back which is so stereotypical for the gfs.

[Ntxw]

Whats the new gfs saying as it is running right know i believe and for the later new years eve time frame as the gfs lost that storm but has brought it back which is so stereotypical for the gfs.

It lost the new year's storm, pushing it further north and dry. Though upper flow suggests disturbances moving through. Wait and see approach.

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.


gfs showing winter precip over northern, nc, nw tx into ok for tues,wed time frame still
based off what iam seeing this run... THIS RUN... this is *NOT* my forecast but iam not locked in any thought rightnow based off this, nam i would say dallas-fortworth metroplex possibly a inch or two of snow. rightnow 2 inch would be the high side of things further north and west back my way again and into ok there could be some areas closer to say maybe 4 inches.. this is still all up in the air iam gonna take tomorrow to very closely study everything, review data over the last 48 hrs or so and take into acct tomorrow's run and go from there..

[weatherguy425]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.


While 540 isn't exactly the magic number for frozen precip.. but the line is fairly far NW of the metroplex while surface temps are below freezing as far south as waco and austin for a part of the day on tuesday, which i think would suggest a freezing rain event...

[iorange55]

This could be one of the best winters in awhile


DFW NWS discussion

.DISCUSSION...
ELONGATED SURFACE HIGH PRESSURE CELL WILL CONTINUE TO BUILD INTO
THE REGION TODAY AS THE LARGE MIDWEST CYCLONE WINDS DOWN AND HEADS
OFF TO THE EAST. NW WINDS WILL BRING ABOUT WEAK COLD ADVECTION TO
THE AREA...WITH CONTINUED COLD BUT PLEASANT WEATHER THE NEXT
COUPLE DAYS. OF NOTE WILL BE SOME INCREASING HIGH CLOUDS TODAY AND
ESPECIALLY MONDAY AS THE SUBTROPICAL JET STREAM BECOMES ACTIVE.

PRIMARY CONCERN THIS FORECAST IS THE POTENTIAL FOR ANOTHER ROUND
OF WINTRY PRECIP ON TUESDAY. IMPRESSIVE SPLIT IN THE UPPER FLOW
WILL ORGANIZE MONDAY AS A WELL DEFINED SHORTWAVE TROUGH MOVES
THROUGH NORTHERN MEXICO UNDERNEATH A RIDGE AXIS SITUATED OVER THE
ROCKIES. THIS PATTERN CLOSELY MATCHES ONE OF THE SIX SYNOPTIC
PATTERNS THAT BRING SNOW EVENTS TO THE REGION /SEE THE LAST NWA
DIGEST ISSUE FOR THE WRITE-UP/. CLIMATOLOGY OF THIS PATTERN SAYS
ACCUMULATING SNOWFALL TENDS TO OCCUR NW OF A SAN ANGELO TO PARIS
LINE...AND ALSO MOISTURE IS PLENTIFUL BUT THERMAL PROFILES HAVE A
TOUGH TIME STAYING BELOW FREEZING AND THUS BECOME THE LIMITING
FACTOR. ADDING TO OUR CONFIDENCE OF SNOWY MODEL FORECASTS...IS
THAT THEY ARE ALIGNED WITH THIS CLIMO SIGNAL. MODELS DEPICT
PLENTIFUL PACIFIC/GULF MOISTURE...A THERMAL PROFILE BARELY COLD
ENOUGH TO SUPPORT SNOW...WITH ACCUMULATING SNOW MOST LIKELY NW OF
A COMANCHE TO ATHENS LINE.

INTERROGATING THE MODELS FOR THE FINER DETAILS...WE SEE FAIRLY
STRONG ISENTROPIC LIFT WILL SPREAD INTO NORTH TEXAS FROM THE SW
LATE MONDAY NIGHT AND CONTINUE UNTIL THE TROUGH AXIS PASSES
THROUGH TUESDAY NIGHT. THE THERMAL PROFILE ALTHOUGH INITIALLY WILL
BE ABOVE FREEZING...SHOULD RAPIDLY COOL ONCE PRECIPITATION BEGINS
DUE TO DRY AIR AND EVAPORATION. MODELS TODAY HAVE COME IN A LITTLE
COOLER WITH TEMPS IN THE ALL IMPORTANT 700-850MB LAYER...AND
SUGGEST PRIMARILY SNOW OVER THE NW HALF OF THE CWA AND RAIN OVER
THE FAR SE. SOMEWHERE IN BETWEEN...ROUGHLY FROM LAMPASAS TO TYLER
A MIX OF RAIN/SNOW OR A CHANGE OVER LINE WILL SET UP. BECAUSE
PRECIPITATION WILL BE GENERATED VIA ISENTROPIC LIFT IN THIS WARM
ADVECTION REGIME...THE RAIN/SNOW LINE WILL STEADILY ADVANCE NORTH
DURING THE DAY TUESDAY AND TUESDAY NIGHT. SURFACE TEMPS WILL
PROBABLY SETTLE AT 32F WHERE/WHEN THERE IS SNOW IS FALLING...BUT
ONCE SNOW CHANGES TO RAIN...THEY WILL WANT TO CREEP UPWARD...SO
THE THREAT FOR FREEZING RAIN IS LOW. WILL STAY CONSERVATIVE WITH
SNOW AMOUNTS FOR NOW...BUT THE BEST INTERSECTION OF HIGHEST QPF
AND SUBFREEZING COLUMN SUGGESTS SNOW ACCUMULATIONS OVER AN INCH
IN THE WEST...HALF INCH NORTH...AND LESSER AMOUNTS ELSEWHERE.

SOUTHERLY WINDS TUESDAY NIGHT AND WEDNESDAY WILL RESULT IN A
SLIGHT WARMING TREND...BUT THE NEXT UPPER TROUGH AND COLD FRONT
WILL ARRIVE THURSDAY. SOME MODELS SUGGESTING A CHANCE OF
PRECIP/SNOW AGAIN THURSDAY BUT WILL KEEP FORECAST DRY DUE TO
CONCERNS ABOUT MOISTURE. THE COLDER THAN NORMAL CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND...BUT WE SHOULD SEE A GRADUAL WARMING
TREND EACH DAY WITH GENERALLY SUNNY SKIES.

FINALLY...A LOOK BEYOND THIS FORECAST PERIOD SUGGESTS WE WILL NEED
TO KEEP AN EYE ON THE FATE OF AN EXTREMELY COLD AIRMASS THAT
WILL BE ORGANIZING IN NORTHERN CANADA. GFS/ECMWF FOR SEVERAL DAYS
HAVE BEEN BRINGING A POLAR VORTEX FROM SIBERIA ACROSS THE NORTH
POLE INTO THE CANADIAN ARCHIPELAGO. GFS KEEPS THE COLD AIR BOTTLED
UP...BUT THE ECMWF FOR A COUPLE DAYS HAS BEEN INDICATING A GOOD
UPPER PATTERN TO ALLOW THIS AIRMASS SOUTHWARD JAN 5-8. LAST RUN OF
THE ECMWF HAS A SURFACE HIGH OF 1066MB NORTH OF ALASKA...WHICH IS
THE HIGHEST I HAVE EVER SEEN THAT MODEL FORECAST.

[iorange55]

Btw GFS 06z look at about 216 hours and beyond.



wow.

[DentonGal]

Btw GFS 06z look at about 216 hours and beyond.



wow.

I'm new here iorange55, but if I'm reading it right, we're looking at 1/07/10 through 1/12/10 with highs in the teens. Is that correct? Wow is right!

[msstateguy83]

if that were correct that would be some record breaking cold.. highs in the teens lows single digits to as low as like 5 below zero.

[Portastorm]

if that were correct that would be some record breaking cold.. highs in the teens lows single digits to as low as like 5 below zero.

Fortunately the 6z GFS run looks screwy. Did you check out the upper level flow at that time? It's all wrong for a true Arctic, pipe-busting outbreak for Texas from the trajectory of the upper flow to the fact that the high is only 1037mb by the time it enters the continental US to the fact that it's not coming down from Montana and slipping down the leeside of the Rockies.

But the "trend" should be of note especially since the Euro is hinting the same thing.

[msstateguy83]

i didnt look @ that portastorm just answering the ? and was going of the fd out of fws but good point if the trajectory of the upper flow looks like such. but yeah take that with the euro should be watched closely. waiting for the 12z nam, running should be done shortly..

[Portastorm]

i didnt look @ that portastorm just answering the ? and was going of the fd out of fws but good point if the trajectory of the upper flow looks like such. but yeah take that with the euro should be watched closely. waiting for the 12z nam, running should be done shortly..

No worries ... just offering an observation.

I'm also curious to see what the 12zNAM has to offer. I do agree with your thoughts though in that you guys (North Texas) look good for another winter weather event. The big question is does the trough stay "open" as it crosses Texas or does it close off into a low? That will dictate who gets what in terms of precip/amounts, etc.

So ... how much snow is still on the ground in good, ol' Wichita Falls?

[msstateguy83]

still to dang much lol i have not checked to see how much officially has melted off but it has not
been much considering temps both christmas day, yesterday were only about 34-35 here. per
the list i saw lastnight i think just about every church in town canceled sunday services this
morning, (or atleast pretty close to every church) lol but i officially had almost 13 inches here
in the middle of the yard away from any areas where it would have drifted up. trust me if it
worked as easy as getting a u-haul, shipping it all to austin i would do that for ya lol

[Portastorm]

still to dang much lol i have not checked to see how much officially has melted off but it has not
been much considering temps both christmas day, yesterday were only about 34-35 here. per
the list i saw lastnight i think just about every church in town canceled sunday services this
morning, (or atleast pretty close to every church) lol but i officially had almost 13 inches here
in the middle of the yard away from any areas where it would have drifted up. trust me if it
worked as easy as getting a u-haul, shipping it all to austin i would do that for ya lol

That may be the only snow I would get this year at the rate we're going! Mighty kind offer!

I suspect y'all will be talking about the Christmas Blizzard of 2009 for years to come. But somehow I think that won't be the only winter weather event you see this year. More to come!!