Texas Winter 2012-2013

[Ntxw]

Today everything is a business! Good thing that Accuweather Pro has some great data of the ECMWF. Weatherbell has some great Model data too

Regarding the Christmas/Post Christmas storm the Operational and Ensemble Runs are still having a hard time forecasting....I suggest people dont get too caught up on any particular run just yet..

Yeah I used to do Accuwx pro for the text output, but it was starting to add up too much for my student budget! That's something I'd like weatherbell to do, it would come in handy. Of course now we have Wxman57 and his millimeter maps

[Ntxw]

It's coming folks. CFSv2 recent runs and ensembles still suggest the likelihood of some kind of REAL arctic outbreak to begin the first week of January, probably one of those once every many years type stuff if they are correct.



I made a post in early December that around the 15th would be centered for a regime shift. That change actually began around the 10th sending stronger and stronger fronts while adding snow cover across the country and next week's system is likely the final blow in the transition to the warmth and we settle into a prolonged cold period.

[ThunderSleetDreams]

Well hello there Fort Yukon... come on down!

[iorange55]

I don't disagree, Ntxw. I said a few days ago I didn't think that there would be any "record-breaking" temps, but I am starting to think twice....

There is a lot of cold to go around.

[SaskatchewanScreamer]

Well hello there Fort Yukon... come on down!

By any chance did you happen to notice whose province that ever so pretty *cold* purple colour is already in??????

And you want that -51C to come on down?????

Oh please come up and visit me........I have all kinds of lovely outings planned for you.

[ThunderSleetDreams]

Well hello there Fort Yukon... come on down!

By any chance did you happen to notice whose province that ever so pretty *cold* purple colour is already in??????

And you want that -51C to come on down?????

Oh please come up and visit me........I have all kinds of lovely outings planned for you.

I'd love some negative readings on the Gulf Coast. Cold air does not phase me... I have enough Gander Mountain Cold Weather gear to dress a small army. That's just some tough hiking weather in Saskatchewan, am i right?!

[CaptinCrunch]

Part of the NWS AFD, Well at least the part that counts....lol

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
407 PM CST THU DEC 20 2012

.DISCUSSION...

MONDAY THROUGH WEDNESDAY...ON MONDAY WE WILL BE CLOSELY WATCHING
THE PROGRESS AND INTENSITY OF THE COLD FRONT AS IT MOVES SOUTH
THROUGH THE PLAINS. AS THE PREVIOUS FORECAST DISCUSSION
MENTIONED...THE SPEED AND BAROCLINICITY OF THIS FRONT WILL PLAY A
ROLE IN WHERE OUR CHRISTMAS DAY STORM SYSTEM MOVES OVER THE
SOUTHERN PLAINS ON TUESDAY AND TUESDAY NIGHT. THE
GFS/ECMWF/CANADIAN ALL SHOW AT LEAST A SHALLOW COLD FRONT SINKING
SOUTH ALL THE WAY THROUGH THE CWA BY MONDAY AFTERNOON. NEARLY ALL
GUIDANCE SHOWS THIS FRONT MOVING THROUGH NORTH TX DRY...DUE TO
LIMITED DEPTH OF MOISTURE AND LACK OF UPPER LEVEL SUPPORT MONDAY
AFTERNOON. AS A RESULT...WENT AHEAD AND SHAVED POPS BACK TO THE
FAR SOUTHEAST PORTIONS OF THE FORECAST AREA FOR MONDAY AFTERNOON
AND ONLY MENTIONED RAIN SHOWERS AT THIS TIME.

WHERE THE MODELS SEEM TO DIFFER MOST SIGNIFICANTLY IS ON THE SPEED
OF STRONG COLD AIR ADVECTION DOWN THE HIGH PLAINS LATE MONDAY
AFTERNOON THROUGH THE OVERNIGHT HOURS. THIS IS MOST EVIDENT BY
LOOKING AT PROGGED H850 WINDS AND TEMPERATURES ALONG THE HIGH
PLAINS DURING THIS TIME FRAME. THE GFS IS ANYWHERE FROM 6 TO 12
HRS SLOWER WITH AN INTRUSION OF COLD...CANADIAN AIR DOWN THE HIGH
PLAINS FROM EARLY CHRISTMAS/TUESDAY MORNING THROUGH THE DAYTIME
HOURS. AS A RESULT...THE GFS TAKES THE NEXT POWERFUL UPPER LEVEL
STORM SYSTEM ON A MORE NORTHERLY TRACK OVER THE SOUTHERN PLAINS
TUESDAY AFTERNOON WITH THE ECMWF AND CANADIAN OFFERING UP THE MORE
SOUTHERLY TRACKS. ASSUMING THIS STRONG LOW-LEVEL COLD AIR
ADVECTION PLAYS AN IMPORTANT ROLE IN HOW FAR SOUTH THE UPPER LOW
WILL GO...FAVOR THE ECMWF AND CANADIAN TRACKS MORE SO THAN THE GFS
AT THIS TIME. THE PRIMARY REASON FOR THIS IS BECAUSE COLD AIR
TYPICALLY RACES SOUTH DOWN THE HIGH PLAINS MUCH FASTER THAN MEDIUM
RANGE GUIDANCE INDICATES. THEREFORE...TEND TO FAVOR THE MODELS
THAT SHOW A FASTER TRACK OF THE COLD AIR...AND A MORE SOUTHERLY
TRACK TO THE UPPER LOW OVER THE SOUTH PLAINS.

WITH THE DECISION MADE TO FAVOR THE MORE SOUTHERLY TRACK...WENT
AHEAD AND MENTIONED A CHANCE FOR PRECIPITATION TO CHANGE OVER TO
SNOW OR A RAIN/SNOW MIX AFTER SUNSET ON CHRISTMAS DAY FOR PORTIONS
OF NORTH TX. AT THIS TIME IT LOOKS AS THOUGH A CHANGE OVER TO SNOW
WILL BE TRYING TO KEEP PACE WITH PRECIPITATION ENDING FROM WEST TO
EAST ACROSS NORTH TX AS DRY MID-LEVEL AIR BUILDS OVER THE REGION
BEHIND THE UPPER LOW. AS SUCH...THINK THAT ANY SNOW WILL TEND TO
BE LIGHT AND ONLY LAST A COUPLE OF HOURS BEFORE ENDING TUESDAY
NIGHT. HAVE SOME CHANCE FOR SNOW...OR A RAIN/SNOW MIX MENTIONED IN
THE FORECAST TUESDAY NIGHT FOR MOST LOCATIONS NORTHWEST OF A LINE
FROM CANTON TO TEMPLE. AT THIS TIME...BECAUSE THE CHANGE OVER TO
SNOW APPEARS TO OCCUR AFTER WE LOSE ANY CONNECTION TO GULF
MOISTURE...VERY LITTLE IMPACT IS EXPECTED AT THIS TIME. HAVE
SNOWFALL OF ONE TENTH OF AN INCH OR LESS IN THE FORECAST AT THIS
TIME.

THERE REMAINS A GREAT DEAL OF UNCERTAINTY IN THE FORECAST...AS WE
ARE STILL STRUGGLING WITH FORECASTING THE PLACEMENT OF
LARGE/SYNOPTIC SCALE FEATURES. SMALLER SCALE DETAILS WILL HAVE A
LARGE IMPACT ON THIS SYSTEM...INCLUDING CHANCES AND AMOUNTS OF
SNOW POSSIBLE. THE FORECAST MAY UNDERGO LARGE CHANGES TO EITHER A
COMPLETELY DRY FORECAST TO MORE ACCUMULATING WINTRY WEATHER
DEPENDING ON THESE SMALLER SCALE...BUT VERY IMPORTANT CONCERNS.
THESE SMALLER SCALE FORECAST DETAILS WILL NOT LIKELY BE WELL
HANDLED UNTIL SUNDAY NIGHT INTO MONDAY AS WE GET A BETTER
CONSENSUS ON THE SPEED AND INTENSITY OF THE INITIAL COLD FRONT
MOVING SOUTH THROUGH THE PLAINS.

EXTENDED...THE POWERFUL UPPER LEVEL STORM SYSTEM MOVES EAST ON
WEDNESDAY LEAVING A DRY FORECAST AND BELOW NORMAL TEMPERATURES
OVER THE REGION FOR THE REMAINDER OF THE WEEK.

[SaskatchewanScreamer]

Well hello there Fort Yukon... come on down!

By any chance did you happen to notice whose province that ever so pretty *cold* purple colour is already in??????

And you want that -51C to come on down?????

Oh please come up and visit me........I have all kinds of lovely outings planned for you.

I'd love some negative readings on the Gulf Coast. Cold air does not phase me... I have enough Gander Mountain Cold Weather gear to dress a small army. That's just some tough hiking weather in Saskatchewan, am i right?!

It will phase you when I'm through with you......trust me!

[Ntxw]

By any chance did you happen to notice whose province that ever so pretty *cold* purple colour is already in??????

And you want that -51C to come on down?????

Oh please come up and visit me........I have all kinds of lovely outings planned for you.

They do not spare central and southern Canada. They build heights into Alaska (-EPO) and you become the new north pole .

[iorange55]

Let's just all ignore the 18z GFS. It's just a bratty teenager wanting attention.

[SaskatchewanScreamer]

By any chance did you happen to notice whose province that ever so pretty *cold* purple colour is already in??????

And you want that -51C to come on down?????

Oh please come up and visit me........I have all kinds of lovely outings planned for you.

They do not spare central and southern Canada. They build heights into Alaska (-EPO) and you become the new north pole .

Then you become the new Saskatchewan.

[Ntxw]

Let's just all ignore the 18z GFS. It's just a bratty teenager wanting attention.

18z is a complete mess. You can see all the windfields all over the place at 5h. It's likely to be more consolidated at the base of the trough to the left and right of the big high block over the Hudson Bay. Should be one big storm to the southwest and one over Maritime Canada like the ensemble.

[horselattitudesfarm]

So, we really don't know much more than we did yesterday! We do know the general timing and we know there will be a storm, but where will the storm track end up...and when will the cold air arrive? It's safe to assume that the models are being a little slow with the cold.

Tonight's runs should be interesting.

I'm gonna use the EYE Models. I use 2 of them that always work in realtime and are always accurate and always agree with each other. Right now the EYE Models show swaying trees flagging to the south-southeast, clear skies with a tinge of brown particulate, and lots of dead vegetation covered with dried reddish dirt courtesy of last nights red-rain fest (muddy rain that left my car looking like a leopard with red spots).

[iorange55]

Just thought I'd share Steve McCauley's (local weatherman) most recent thoughts posted on his Facebook page...

Our Christmas Storm is really looking impressive on the latest satellite imagery ... new data sets are coming in, and I will be posting updates.

This will be yet another major winter storm to strike the central US, and the question remains: will the data continue to suggest it will pass north of DFW and just give us a chance for rain and a brief shot at a brief sleet shower or snow flurry? Or will the storm change its path at the last minute?

And...

Alrighty then ... models are now ALL OVER THE PLACE (i.e., chaos levels just shot off the charts) in their depiction of next week's storm. But here is the best guess at this point.

Cold air arrives early Christmas morning now, bringing light rain showers that transition to light sleet and then to flurries in north Texas by late afternoon. Precip amounts still appears to be very light.

And because the precip will be light, there is a good chance that the screaming winds that will be occurring at the same time will evaporate much of the precipitation.

Since this storm is still over the Pacific it is not being sampled by any weather balloons from the United States, and this is a very complex-looking storm system (see earlier post of the satellite image of this storm). This is probably why we have seen a big shift in the precipitation pattern to our north. Notice that Oklahoma no longer appears to be the main target of this storm ... at least for now!

So stay tuned for periodic updates, espcially by the weekend as this storm should finally be pushing into the United States and will at that time be fully sampled by our upper-air observation network."

So...he's basically in the same clueless boat that we are.

[DonWrk]

Why did James Spann say things have came into better agreement today? He linked to a weather blog alabamawx.com I believe.

[SaskatchewanScreamer]

Alrighty then ... models are now ALL OVER THE PLACE (i.e., chaos levels just shot off the charts) in their depiction of next week's storm. But here is the best guess at this point.

Cold air arrives early Christmas morning now, bringing light rain showers that transition to light sleet and then to flurries in north Texas by late afternoon. Precip amounts still appears to be very light.

And because the precip will be light, there is a good chance that the screaming winds that will be occurring at the same time will evaporate much of the precipitation.

Since this storm is still over the Pacific it is not being sampled by any weather balloons from the United States, and this is a very complex-looking storm system (see earlier post of the satellite image of this storm). This is probably why we have seen a big shift in the precipitation pattern to our north. Notice that Oklahoma no longer appears to be the main target of this storm ... at least for now!

So stay tuned for periodic updates, espcially by the weekend as this storm should finally be pushing into the United States and will at that time be fully sampled by our upper-air observation network."

So...he's basically in the same clueless boat that we are.[/quote]


I feel so much better now.

[Palmer divide shadow]

[SaskatchewanScreamer]

oooooooooooops read that too quickly and went out for supper.....I was laughing about the use of *screaming winds* NOT the evaporation (I didn't even notice that til now)!!!

Thought I'd better clear that mess up.

Sorry I don't wish drought on you folks!

edited to put this in....I was going to send it just to Vbhoutex but thought it would be better here:

I apologize for causing hard feelings. I really truly didn't notice the word evaporation til after I came back from supper. I seem to get caught up in the joking around and decide to cut and paste something that tickles my funny bone without carefully reading the whole posting first.

I knew as soon as I noticed the Texan thread hadn't moved and my name was still showing as last poster I'd screwed up again.

I really really have to learn NOT to cut and paste anything unless I have time to read it carefully (vs. my unthinking quick scan).

I just feel so bad ruining the thread by my thoughtlessness.

all I could say was crap.

I feel like that too as I know drought is no laughing matter down there.

[Ntxw]

Nothing like a nice hot cup of cocoa on a chilly night awaiting the suite of 0z runs!

NAM goes out to the 24th now, not far enough but it begins the digging process in California. It is the long range nam though which isn't reliable.

[Ntxw]

Since we're all waiting, here is a little special discussion from FW. What a great forecasting bunch we have here in north Texas.


****
THE CHRISTMAS NIGHT FORECAST IS ON EVERYONE/S MIND. WE HAVE BEEN
WATCHING THIS SYSTEM IN THE EXTENDED MODELS FOR SEVERAL DAYS...AND
CONTINUE TO RIGHTLY ASSESS THAT A POTENTIAL FOR A WINTER EVENT
EXISTS. UNFORTUNATELY MODEL GUIDANCE DOES NOT HAVE THE SKILL IN
THAT TIME RANGE TO ACCURATELY PREDICT THE INTENSITY AND LATITUDE
THE UPPER LEVEL SYSTEM WILL TAKE BECAUSE OF THE UNCERTAINTY ON
EXACTLY WHERE A COLD FRONT WILL BE ON TUESDAY. AS WE HAVE SAID IN
THE LAST 2 AFDS...THIS COLD FRONT IS THE KEY TO THE FORECAST.

BUT TO UNDERSTAND WHY...IT IS HELPFUL TO DISCUSS BAROCLINICITY
AND ITS AFFECTS ON THE MOVEMENT AND STRENGTH OF WEATHER SYSTEMS.
ESSENTIALLY THESE STORM SYSTEMS ARE BLOBS OF UPPER LEVEL
ENERGY...OR VORTICITY...OFTEN CALLED SHORTWAVES OR DISTURBANCES.
IN AN ATMOSPHERE WHERE THERE IS VERY LITTLE TEMPERATURE DIFFERENCE
FROM LOCATION TO LOCATION...THE MOTION OF THESE DISTURBANCES IS
BASICALLY DICTATED BY THE FLOW THEY ARE A PART OF. THEY BEHAVE
MUCH LIKE A LEAF WOULD IF IT WERE FLOATING DOWN A RIVER.

HOWEVER WHEN HORIZONTAL TEMPERATURE GRADIENTS EXIST...SUCH AS
WHEN A COLD FRONT IS NEARBY...THIS SIMPLE RULE GOES OUT THE
WINDOW. THIS IS CALLED A BAROCLINIC ATMOSPHERE. A DISTURBANCE THAT
MOVES INTO A BAROCLINIC ZONE WILL INTENSIFY. THIS IS BECAUSE LOW
LEVEL TEMPERATURE ADVECTION BEGINS TO INTERFACE WITH THE UPPER
LEVEL SYSTEM. IN SHORT...THERMAL ADVECTION IN THE LOW LEVELS
CAUSE HEIGHT CHANGES IN THE UPPER LEVELS...WHICH IN TURN
STRENGTHEN THE UPPER LEVEL VORTICITY CENTER...WHICH IN TURN
STRENGTHENS THE LOW LEVEL THERMAL ADVECTION...AND ETC. THE WHOLE
THING BECOMES A FEEDBACK LOOP. AN UPPER DISTURBANCE UNDERGOING
BAROCLINIC INTENSIFICATION WILL TRANSFORM INTO A CYCLONE AND WILL
NO LONGER MOVE WITH THE MEAN FLOW...BUT WILL CURVE TOWARD THE
POLE. IN THE PROCESS OF TURNING TOWARD THE POLE THE CYCLONE
OFTEN OCCLUDES...MEANING THEY LOSE THEIR ACCESS TO THE TEMPERATURE
GRADIENTS AND THEY WEAKEN. WE HAVE ALREADY SEEN MANY MODEL RUNS OF
A BIG WINTER CYCLONE DEVELOPING OVER THE SOUTHERN PLAINS AND
CURVING OFF TO THE NORTH. IN THE LATEST MODELS WE NO LONGER SEE
THAT SOLUTION AND SEE A WEAK TROUGH MOVING OVERHEAD.

THE REASON WHY THE MODELS HAVE BEEN ALTERNATING BETWEEN A POWERFUL
WINTER CYCLONE IN THE PLAINS AND A WEAK DISTURBANCE HAS BEEN DUE
TO THE LOCATION OF THE BAROCLINIC ZONE /OR COLD FRONT/ WHEN THE
DISTURBANCE REACHES THE SOUTHERN PLAINS. THE TREND IN MOST OF THE
MODELS HAS BEEN TO MOVE THE FRONT/BAROCLINIC ZONE INTO SOUTH
TEXAS. AS A RESULT THE UPPER LEVEL DISTURBANCE TRAVELS OVER TEXAS
WITHOUT STRENGTHENING BECAUSE THE TEMPERATURE GRADIENTS ARE WEAK
SO FAR BEHIND THE FRONT. THE SYSTEM THUS DOES NOT INTENSIFY UNTIL
IT REACHES THE NORTHERN GULF COAST WHERE A BAROCLINIC ZONE EXISTS.
THIS SCENARIO...WHICH WE ARE CURRENTLY FORECASTING...IS ONE THAT
WOULD ONLY PRODUCE LIGHT AMOUNTS OF WINTER PRECIP. THIS IS BECAUSE
THE SYSTEM WILL BE WEAK AND HAS NO ACCESS TO THE THERMAL GRADIENTS
IT NEEDS TO INTENSIFY. AN INTENSIFYING LOW WOULD BE ABLE AUGMENT
THE WIND FIELDS AND THUS TAP INTO THE GULF FOR MOISTURE.

IN ORDER TO GET A SIGNIFICANT SNOW STORM HERE...WE WOULD NEED THE
FRONT TO BE FARTHER NORTH THAN CURRENTLY FORECAST...BUT NOT SO FAR
NORTH THAT THE SYSTEM BEGINS ITS POLEWARD TURN AND STAYS NORTH OF
THE REGION ALTOGETHER. WE NEED A GOLDILOCKS POSITION OF THIS
FRONT. AGAIN...KNOWING THE PRECISE LOCATION OF A FRONT BEYOND 5
DAYS IS THE DIFFICULTY WITH THIS FORECAST. THANKFULLY THE LEAD
SHORTWAVE RESPONSIBLE FOR THE LOCATION OF THIS FRONT WILL BE
ONSHORE IN CALIFORNIA SATURDAY AND WILL BE SAMPLED BY THE BALLOON
NETWORK. IN ADDITION...WE WILL BE IN RANGE OF THE NAM BY TOMORROW
FOR HAVING ANOTHER OPINION ON THIS FRONT/S STRENGTH AND LOCATION
MONDAY NIGHT AND TUESDAY...EVEN IF WE DONT GET AN EXPLICIT DEC
25TH FORECAST FROM THE NAM UNTIL SATURDAY.