Southern Plains winter wx thread (2009-2010)

[Extremeweatherguy]

Temperatures continue to fall in and around Oklahoma City tonight. Here is a look at the current conditions being reported around the region (as of just before midnight)...

Oklahoma City Will Rogers Airport
Time: 11:52pm
Temperature: 21F
Wind Chill: 4F

Oklahoma City Wiley Post Airport
Time: 11:53pm
Temperature: 20F
Wind Chill: 4F

Spencer, OK Mesonet Site
Time: 11:55pm
Temperature: 20F
Wind Chill: 7F

Norman/Max Wesheimer
Time: 11:31pm
Temperature: 23F
Wind Chill: 10F

Norman, OK Mesonet Site
Time: 11:55pm
Temperature: 21F
Wind Chill: 6F

El Reno, OK Mesonet Site
Time: 11:55pm
Temperature: 18F
Wind Chill: 2F

Guthrie, OK Mesonet Site
Time: 11:55pm
Temperature: 19F
Wind Chill: 4F

Link to view the very latest conditions: http://www.mesonet.org/

[Extremeweatherguy]

Both the 00z GFS and 00z ECMWF have backed off a little bit on early next week's potential arctic blast. They once again are trying to hold the cold air up to our north, eventually sending the majority of it to our north and east by mid next week.

And so the back and forth with the models continues..

[iorange55]

Both the 00z GFS and 00z ECMWF have backed off a little bit on early next week's potential arctic blast. They once again are trying to hold the cold air up to our north, eventually sending the majority of it to our north and east by mid next week.

And so the back and forth with the models continues..

GFS 06 is bringing it back lol oh the drama, huh?

[srainhoutx]

Hmmm...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
400 AM EST WED DEC 09 2009

VALID 12Z SUN DEC 13 2009 - 12Z WED DEC 16 2009

IN THE LARGE SCALE MODELS AND ENSEMBLE MEANS OFFER GENERALLY
AGREEMENT THAT FLOW SHOULD EVOLVE TOWARD AN ERN PAC TROF/WRN NOAM
RIDGE/ERN NOAM TROF CONFIGURATION BY THE MIDDLE OF NEXT WEEK.
SOME FCST DETAILS LEADING UP TO THIS PATTERN REMAIN IN QUESTION
THOUGH. GUIDANCE SHOWS CONSIDERABLE SPREAD WITH FLOW ACROSS SRN
CANADA AND THE NRN CONUS WITH PERHAPS A MORE DIVERSE ARRAY OF
SOLNS THAN 24 HRS AGO. AT THE VERY LEAST THE 00Z ECMWF IS ON THE
WRN EDGE OF THE GUIDANCE SPREAD WITH ITS SRN CANADA CLOSED LOW...
AND WITH TELECONNECTIONS RELATIVE TO THE LATE-PERIOD ERN PAC MEAN
TROF SUPPORTING A MODERATELY AMPLIFIED ERN NOAM TROF... THE ECMWF
MAY BE TOO SLOW TO TRACK THIS UPPER LOW EWD AND BY DAY 7 WED MAY
BE A LITTLE TOO FLAT WITH THE ERN CONUS TROF. STILL... EARLIER IN
THE PERIOD THERE ARE INDICATIONS FROM OTHER GUIDANCE INCLUDING THE
UKMET/GFS/GEFS MEAN THAT GO ALONG WITH THE 00Z ECMWF SLOWER TREND
FOR THE SURGE OF COLD AIR INTO THE CNTRL CONUS DURING THE
WEEKEND... SO A MODEST WEIGHTING OF SOME 00Z ECMWF ATTRIBUTES MAY
BE ACCEPTABLE.
WITH PACIFIC FLOW PROGRESSING ACROSS THE CONUS... GUIDANCE IS
ABOUT EVENLY SPLIT AS TO HOW DEFINED ENERGY OVER THE SRN
ROCKIES/PLAINS AS OF EARLY DAY 3 SAT WILL BE WHEN IT REACHES THE
EAST COAST. THESE DIFFS AFFECT EAST COAST/WRN ATLC WAVE
DEVELOPMENT WHICH OVER RECENT DAYS HAS SHOWN SOME OSCILLATING
NWD/SWD TRENDS. LATEST TRENDS ARE MORE SUPPRESSED ON AVERAGE BUT
THE GFS/UKMET MAINTAIN A BETTER DEFINED SHRTWV ALOFT AND SFC WAVE
VERSUS THE ECMWF/CANADIAN. GIVEN SIGNIFICANT MULTI-DAY
ADJUSTMENTS AND OPC COORDINATION WILL FAVOR A GFS/ECMWF COMPROMISE
WITH THIS WAVE. UPSTREAM THERE IS DECENT CLUSTERING WITH A TROF
MOVING INTO THE SOUTHWEST AND VICINITY BY SUN-MON BUT CONSIDERABLE
UNCERTAINTY WITH WHAT PROPORTION OF ENERGY MAY BE PICKED UP BY NRN
STREAM FLOW VERSUS CONTINUING EWD ACROSS THE SRN CONUS. AN
ENSEMBLE MEAN CONSENSUS APPEARS BEST UNTIL BETTER OPERATIONAL
AGREEMENT EMERGES. FINALLY WITH ERN PAC DEVELOPMENT LATE IN THE
PERIOD... THERE IS EMBEDDED DETAIL SPREAD BUT OTHERWISE DECENT
AGREEMENT IN PRINCIPLE FOR A DAYS 6-7 FCST.

IN LIGHT OF LOW CONFIDENCE WITH SOME ASPECTS OF THE DAYS 3-7
SAT-WED FCST... PREFER TO MAKE ONLY A PARTIAL CONTINUITY
ADJUSTMENT TOWARD IDEAS OF LATEST GUIDANCE. THIS IS BEST ACHIEVED
BY A BLEND OF 00Z/12Z ECMWF RUNS AND 00Z GEFS/12Z ECMWF ENSEMBLE
MEANS... LOCALLY ADJUSTED TO ADD DEFINITION OR IN THE CASE OF THE
SYSTEM OFF THE WEST COAST LEAN A LITTLE MORE TOWARD THE GFS BASED
ON SHORT TERM PREFERENCES. FEATURES FOR WHICH THERE IS BETTER
AGREEMENT ARE FAIRLY WELL CAPTURED BY THIS BLEND.

RAUSCH

[Extremeweatherguy]

It is very cold in central Oklahoma today! After starting the morning in the mid teens (with wind chills as cold as -2F), we have only managed to warm up into the lower to middle 20s as of 12:30pm (with windchills still near 5-15F). It looks like we might *optimistically* make it into the upper 20s for a high today, before then entering a free fall in temperatures just after sunset. It appears quite possible that we may flirt with single digit readings by tomorrow morning if we can get some good radiational cooling overnight.

[srainhoutx]

Here is something we haven't seen so far this winter season. VIS Imagery shows a lot of snow cover to our N...

http://adds.aviationweather.noaa.gov/sa ... &itype=vis

[BlueIce]

So all the local forecasts for OKC have the temperatures rebounding by Friday and ending up with mid 50's on Saturday. What is going to push the Arctic Air back up to the north?

Is it going to be the low in New Mexico?


It looks like we have a pretty good sized High pressure dome on top of us

[Extremeweatherguy]

The 12z models continue to offer no help with next week's forecast and the potential arctic air.

The 12z ECMWF holds the cold air up in Canada, sending none of it into the southern plains. If it played out, then we would probably see seasonal or above seasonal temperatures for the first half of next week.

The 12z CMC shows the cold air diving full force into the country (including the southern plains) by early next week. If it played out, we would get quite chilly by early to mid next week, with below seasonal temperatures likely.

And the 12z GFS is somewhere in between the two, showing a slight push of colder air into the southern plains by early/mid next week, but nothing extreme. If it played out, we would probably be looking at seasonal or slightly below seasonal temperatures first the first half of next week. By late next week though, the GFS then pushes through a more substantial cold airmass and shows wintery precipitation breaking out in Oklahoma and Texas by Thursday into Friday.

Let the forecasting headaches continue..

[Ntxw]

The models didn't do a good job with the current cold blast just last weekend. Most having it fizzling out or not diving south enough and look at where our temperatures are at now. It's past noon and we've barely crept above the freezing mark in Dallas.

[srainhoutx]

All of the TX WFO's are lowering their high temps forecasted for today.

[OUwx13]

i really don't think the models are handling this at all. what could possibly keep the cold air from Oklahoma and Texas?

BTW: its a very cold day here in Oklahoma! Currently here on campus at OU it is 27F and tonight will be down right cold

[Ntxw]

I've heard there's the possibility the cold air could be shunted more east\southeast than due south (that could be why with a more zonal flow), however historically cold that dense and massive forces it's way south more so than not. We'll see

[rhoby13]

The forecasters down here in Austin were way off today. They all adjusted their forecast about 10 degrees colder this morning. Hasn't made it out of the lower 40's.

[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 the NHC and NWS products.


stickin to my guns.. major arctic air blast later then i first said but it still gonna happen i would say anytime around wednesday but gfs is showing arrival more by mid to late afternoon thu depending on your location bringing with it a chance of snow across ok & n.tx.. this looks like something quite BIG to me that could keep a large section of oklahoma, n.tx in the celler temp wise under the freezing mark for i would say possibly as long as a week which would keep this going thru the christmas holiday! accumulations,exc way way to far out to even go there but lets just say it has the possibilty of being a big big winter storm for the region, i would say it could be a very good memorable one, thing we are gonna have to watch for is temps and is it gonna fall as frz rain, snow and a mix? b/c with a situation like iam predicating it would be no good at all for ice and us being below 32 for that long.. but time will tell, if you look @ the last frame of gfs to iam seeing another re-enforcing shot of arctic air right around christmas time, in the 'flow' i see setting up i see a straight shot for the southern plains region of ok & tx...

dont get to excited yet everyone but its looking more and more likely breakdown chances:

for oklahoma & northern, north-central tx for next week of arctic air & likelyhood
of winter storm ie,snow and or ice: 70%

chance of a winter event happening on christmas day for our region: rightnow i would say 45% just becouse of your getting close to or a few days over 2 weeks out and in meteorology thats like a lifetime with things that could go wrong, but as for the 'trends' and such it looks quite favorable just not totally sold on it yet.


edit: i just got the latest gfs 18z run and to me its junk, i mean ANYTHING is possible but just the wx pattern we are
in the yr for to be expecting above norm precip, below norm temps i dont buy this latest run for NOTHING!! its even
hard for me to believe mid 60s even uptowards w.falls nearing 70 by later in the wkend if you buy into some of this..
for those of you not into the hardcore aspects of reading the raw wx data,exc this happens all the time flip flopping
with the models right before a big event, winter time is the most dificult time for forecasters and honestly sometimes
you just have to go with your gut knowledge & experience..

[Ntxw]

I agree with you to an extent. The warm up looks a bit suspicious to me as already the models have somewhat blown off on the temperatures as of late. 18z gfs isn't exactly the best run to look at either

[Extremeweatherguy]

I am really impressed with just how cold this current airmass turned out to be. After a morning low of just 15F, we only managed to make it up into the mid to upper 20s for a high! Now, at 5:08pm, temperatures are already starting to drop again. We are currently hovering near 23F, and it looks like we will be into the teens just after sunset. This is going to be one long and cooold night! We will probably have sub-20F readings around for a good 12-15 hours between this evening and tomorrow morning.

(BTW: Our average high and low this time of year is 51F/31F.)

[iorange55]

Well according to the GFS 00 not a thing is going to happen.

[PTPatrick]

Hopefully this winter doesnt turn out like last. I seem to remember an arctic blast about this time last year below zero temps made it pretty far south and that was when Denver set its all time record December low of -24. Left me thinking we would salvage a cold and snowy winter...but its never materialized. For us, winter blew its wad early and January and February were about as non snowy as it gets in Denver and February was one of Denvers warmest. Christmas, just 10 days after the 24 below zero record, was brown with highs in the 50s. Lets hope the pattern change doesnt go the same way again...but to look at the 0z GFS it could end up warm til the end of the month.

[Extremeweatherguy]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
322 PM CST THU DEC 10 2009

.DISCUSSION...
A SURFACE RIDGE NOW CENTERED OVER NORTHEASTERN OK WILL MOVE OFF TO
THE EAST OVER THE NEXT 24 HOURS...WITH LIGHT SOUTHERLY WINDS
EXPECTED INTO SATURDAY MORNING. A RELATIVELY CLEAR SKY WILL ALLOW
FOR ANOTHER SOMEWHAT CHILLY MORNING FRIDAY...BUT A RETURN OF LOW
LEVEL SOUTHERLY FLOW WILL BRING US OUT OF THE BASEMENT. MODEL
GUIDANCE FORECASTS HAVE BEEN CLOSELY FOLLOWED THROUGH THIS
WEEKEND...THE LONE EXCEPTION BEING PRECIP TYPE FOR SATURDAY.
THERMODYNAMIC PROFILES INDICATE THAT ANY PRECIP WOULD BE GENERATED
VIA ISENTROPIC LIFT IN A LOW LEVEL HUMID BUT STABLE LAYER WITH
TEMPERATURES ABOVE FREEZING. THIS SPELLS WEAK LIFT AND LIGHT
AMOUNTS OF RAIN OR DRIZZLE. A BRIEF PERIOD OF FREEZING DRIZZLE IS
POSSIBLE IN AREAS OF NORTHERN OK WHERE DEW POINTS MAY STILL BE IN
THE UPPER 20S...BUT ALL AREAS ARE EXPECTED TO BE ABOVE FREEZING BY
MIDDAY.

GUSTY SOUTHWEST WINDS ARE EXPECTED ON SUNDAY...WITH MAXIMUM
TEMPERATURES FORECAST TO BE IN THE 60S AND EVEN LOWER 70S IN
PORTIONS OF SOUTHWESTERN OK AND WESTERN NORTH TX. THIS PERIOD WILL
NEED TO BE MONITORED...AS SOME FIRE WEATHER PRODUCTS MAY
EVENTUALLY BE NEEDED. FOLLOWING THIS...IT APPEARS THAT WE ARE IN
FOR ANOTHER SHOT OF COLD AIR ON MONDAY. THE COLD AIR IS FORECAST
TO SLIDE DOWN THE LEE SIDE OF THE ROCKIES FROM NORTH CENTRAL
CANADA...INDICATIVE OF A SHALLOW COLD AIRMASS. ABOUT 70 PERCENT OF
THE GFS ENSEMBLE MEMBERS SHOW THE CENTER OF THE HIGH OFF TO OUR
NORTHEAST...BUT IN SUCH A POSITION THAT WE WOULD STILL BE COOLING
OFF QUITE A BIT. THE 12Z ECMWF BRINGS THE COLD AIR DIRECTLY INTO
THE CWA. IT IS QUITE LIKELY THAT WE WILL STILL HAVE A FAIR AMOUNT
OF SNOW COVER TO OUR NORTH ON MONDAY...FURTHER MAKING A CASE FOR A
COLD SOLUTION.

THERE IS A SLIGHT CHANCE FOR LIGHT AMOUNTS OF RAIN OR FREEZING
RAIN IN OUR SOUTHEASTERN COUNTIES ON MONDAY AND MONDAY EVENING. BOTH
HIGH AND LOW TEMPERATURES FOR MONDAY THROUGH WEDNESDAY HAVE BEEN
LOWERED FROM THE PREVIOUS FORECAST...WITH GRADUAL WARMING
EXPECTED TO BEGIN ON WEDNESDAY AS THE SURFACE HIGH BEGINS TO MOVE
OFF TO THE EAST. GFS/ECMWF AGREE IN GENERAL ON A WESTERN US
RIDGE/EASTERN US TROUGH PATTERN THROUGH NEXT WEEK...LEAVING US
OPEN TO POSSIBLE FURTHER INTRUSIONS OF COLD AIR FROM THE NORTH.

TAYLOR

[Extremeweatherguy]