Southern Plains winter wx thread (2008-2009)

[Ed Mahmoud]

For a winter event to be truly successful, it must produce freezing/frozen in HOU and cancel school and work.

[Ed Mahmoud]

I'm starting to get excited about Sacramento, 2 GFS runs in a row have shown significant snow accumulation next week. It may be part of the GFS error that denies cold air to us deserving folks in the Plains, but I have Googled, snow in SAC is even rarer than snow in South Texas, and the 0Z GFS would drop a foot, paralyzing the city.

[Ed Mahmoud]

Just looking at the Canadian's depiction of the cold front coming early next week, +10ºC and -20ºC 850 mb isotherms (30ºC spread /54ºF) in about 150 miles. Yowza!

[jinftl]

Huge difference between a cold front...even one that brings 'downright cold' temps throughout the U.S....and one of the top 5 or so arctic outbreaks of the last 100 years which was being hinted at with the references to '89....it is just a matter of perspective...it can get 'crazy cold', even in spots that don't usually see it (along with wintry precip)...but it is very very bold to predict one of the coldest arctic outbreaks of the last 50 or 100 years....3 weeks in advance.

How many times does the Tropics board light up when there is a 7 day model run that shows a Cat 5 hitting Miami? We see a few of these "Andrew, only bigger" scenarios each season it seems in some model run....could it actually happen one time? Sure. Is it likely in any given season? Not really.

Now the model that saw the doomsday scenario still might have been on to something as far as a disturbance forming and even effecting either florida or the southeast U.S....or even Cuba..down the road. But it might just end up being a sheared t.s. off of Charleston, instead of the Cat 5 over downtown Miami.

I immediately thought of that parallel when 1983 or 1989, what could be argued the Cat 5-version of arctic invasions, started getting thrown around a week (or more) ago for what was to come this month. With that amount of hype, there is alot of room for disappointment if that is what folks are expecting to see. Could it happen just as those model runs showed....in terms of timing, location, and severity of cold? It could. But some lesser version of the 'arctic invasion of the century' is more likely. That doesn't mean that whatever comes will be boring though....

It may be cold, but we've had cold weather on and off lately. A few light freezes already as well. I doubt the record-breaking cold and/or wintry precip will pan out, but that's just my uneducated opinion based on these "scares" of 1989, etc. never coming to fruition. I will remain planted in wait-and-see mode, trying not to believe the hype, but always wishing for some snow.

Maybe some of yall should read wxman57's post in the texas winter weather forum...He sounds pretty bold and seems pretty sure that a massive arctic outbreak is in the works. God knows if its true, but it certainly gets my attention, considering he says theres a chance we in dallas might be looking at below freezing temps from sunday night to thursday...

[Ed Mahmoud]

wxman57 doesn't want us to have any fun
(pasted snip from KHOU local weather forum)

Timing is a bit sketchy this far out, as we still don't know what kind of airmass is coming down and when it'll be on the move. However, I'd estimate that the front may reach the Dallas area Sunday night or early Monday morning and the Houston area by Monday night/Tuesday morning.

Interesting that the Houston NWS office is totally buying the GFS solution from overnight and calling for nice warm weather all next week. I certainly don't see any major cold for us next week, the upper flow and lack of snow to the north should keep us from breaking any records. But we could see highs closer to 40 next Tue-Thu. Just enough to be miserable.

Actually, it isn't all bad if we have temps near/below 40 and dry surface air, and can keep advecting cool/dry air down while over-running precip sets up. If we can evaporatively cool to just below freezing, miss work/school, and not damage/kill my more cold sensitive plants (the orange tree, the pygmy date palm), then it would actually be a huge silver lining.

[Extremeweatherguy]

40 in Houston would probably mean below freezing here in Oklahoma City..perfect for wintry weather.

I just hope that any precipitation we do get up here is in the form of sleet/snow and not freezing rain!

[Extremeweatherguy]

Does anyone know what this weird formation forming on OKC radar is?

http://radar.weather.gov/radar.php?rid= ... 1&loop=yes

Is it an indication that flurries may soon start reaching the ground?

EDIT: Nevermind. I think my question has been answered. OKC is now reporting light precipitation reaching the ground.

[Extremeweatherguy]

So far all we have been getting in OKC is freezing drizzle. It is enough to notice when outside, but isn't causing any significant icing problems (yet). Hopefully the changeover to snow flurries will happen soon!

[gboudx]

DFW NWS has just changed us to 20% snow/sleet for the evening. From about 4pm to 10pm there's a chance so get out there with the video camera.

[Extremeweatherguy]

light snow now in OKC.

[gboudx]

Yeah you guys are under a WWA. We have a SWS for a dusting on grassy areas. But, I'll believe it when I see it.

[srainhoutx]

light snow now in OKC.

congrats EWG

[double D]

Make sure you post some pictures EWG.

[cctxhurricanewatcher]

Coldest Temps in 50 years headed to Southern California?

http://www.venturacountystar.com/news/2 ... sights-on/

[Ed Mahmoud]

Coldest Temps in 50 years headed to Southern California?

http://www.venturacountystar.com/news/2 ... sights-on/

See my Sacramento Snow Disaster thread...

[jinftl]

Interesting Discussion with today's CPC 6-10 Day and 8-14 Day Outlooks....mention possibility of freeze event in Southern California...and overall forecast confidence rated a very high 5 out of 5.


PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS, MD
300 PM EST TUE DEC 09 2008

6-10 DAY OUTLOOK FOR DEC 15 - 19 2008

TODAY'S MODEL SOLUTIONS ARE IN EXCELLENT AGREEMENT ON THE 500-HPA CIRCULATION
PATTERN OVER THE FORECAST DOMAIN FOR DAYS 6-10. A STRONG RIDGE IS FORECAST OVER
WESTERN ALASKA, A DEEP TROUGH OVER THE WESTERN CONUS, AND ANOTHER RIDGE (MAINLY
NOTICEABLE IN THE HEIGHT ANOMALY FIELD) ALONG THE EAST COAST. FOR THE MOST
PART, THERE IS NO SIGNIFICANT DIFFERENCE BETWEEN THE ENSEMBLE MEANS AND
OPERATIONAL RUNS TODAY REGARDING THE AMPLITUDE OF THE LONG WAVE FEATURES.
HOWEVER, THERE ARE SIGNIFICANT DIFFERENCES DURING THE WEEK 2 PERIOD BETWEEN THE
DETERMINISTIC GFS MODEL RUNS AND THE ENSEMBLE MEANS WHICH IS VERY IMPORTANT FOR
THE WESTERN CONUS. THIS IS DESCRIBED FURTHER DOWN IN THE WEEK 2 PORTION OF THE
MESSAGE. FOR DAYS 6-10, THE BELOW NORMAL 500-HPA HEIGHTS PREDICTED OVER THE
WESTERN CONUS SHOULD SUPPORT BELOW NORMAL SURFACE TEMPERATURES, WHILE THE ABOVE
NORMAL 500-HPA HEIGHTS IN THE EAST SHOULD SUPPORT ABOVE NORMAL SURFACE
TEMPERATURES. IN ALASKA, RELATIVELY WARM AND WET CONDITIONS ARE FORECAST FOR
WESTERN PORTIONS OF THE STATE, WHILE COLD AND DRY CONDITIONS ARE FORECAST
ELSEWHERE.

TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 15 PERCENT OF TODAY'S OPERATIONAL 0Z
GFS CENTERED ON DAY 8...15 PERCENT OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 8...15 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...15
PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...20 PERCENT OF
TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...5 PERCENT OF TODAY'S
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8...AND 15 PERCENT OF TODAY'S EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 7.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: WELL ABOVE AVERAGE, 5 ON A SCALE
OF 1 TO 5, DUE TO EXCELLENT AGREEMENT AMONG THE MODEL SOLUTIONS.





8-14 DAY OUTLOOK FOR DEC 17 - 23 2008

SLIGHT RETROGRESSION OF THE PREDICTED 6-10 DAY LONG WAVE PATTERN IS INDICATED
FOR WEEK 2. THE ENSEMBLE MEANS ARE IN FAIRLY GOOD AGREEMENT, THOUGH THE 00Z GFS
ENSEMBLE MEAN AND THE CANADIAN ENSEMBLE MEAN PREDICT A NOTICEABLY WEAKER TROUGH
OVER THE WESTERN CONUS, COMPARED TO THE OTHER ENSEMBLE MEANS. THE OPERATIONAL
00Z AND 06Z GFS RUNS DIFFER FROM ALL THE ENSEMBLE MEANS IN THAT THEY FORECAST
SPLIT FLOW ACROSS THE WEST. THE OPERATIONAL RUNS PREDICT THE NORTHERN JET
STREAM ALONG THE CANADIAN BORDER, AND A MID-LATITUDE JET STREAM OVER THE
REMAINDER OF THE CONUS. EMBEDDED WITHIN THIS MID-LATITUDE STREAM IS AN
AMPLIFIED TROUGH ALONG THE WEST COAST AND A RIDGE IN THE SOUTHEAST. THIS
DIFFERENCE BETWEEN THE OPERATIONAL RUNS AND THE ENSEMBLE MEANS IS VERY
SIGNIFICANT BECAUSE IF THE OPERATIONAL RUNS ARE CORRECT IN FORECASTING A SPLIT
FLOW PATTERN, CALIFORNIA WILL DODGE POTENTIALLY DAMAGING FREEZES TO CROPS. THE
ARCTIC AIR WILL BE LOCKED IN OVER THE NORTHERN TIER OF STATES FROM WASHINGTON
TO PERHAPS MINNESOTA, THOUGH VERY SHALLOW ARCTIC AIR CAN BE EXPECTED TO
UNDERCUT THE MEAN JET AND PENETRATE SLIGHTLY FURTHER SOUTH THAN WOULD OTHERWISE
BE ANTICIPATED. THE ENSEMBLE MEAN SOLUTIONS FAVOR A COLDER SCENARIO FOR
CALIFORNIA, BUT AT THIS TIME WE ARE GIVING SIGNIFICANT WEIGHT TO THE HIGHER
RESOLUTION GFS RUNS SINCE THEY SHOULD CATCH ON TO SIGNIFICANT CIRCULATION
CHANGES FIRST.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 15 PERCENT OF TODAY'S OPERATIONAL
0Z GFS CENTERED ON DAY 11...15 PERCENT OF TODAY'S OPERATIONAL 6Z GFS CENTERED
ON DAY 11...20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20
PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20 PERCENT OF
TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...AND 10 PERCENT OF TODAY'S
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: NEAR AVERAGE, 3 ON A SCALE OF 1
TO 5, DUE TO NOTICEABLE DIFFERENCES BETWEEN THE DETERMINISTIC AND ENSEMBLE MEAN
SOLUTIONS. THE GREATEST UNCERTAINTY IS OVER THE WEST.

[Extremeweatherguy]

Make sure you post some pictures EWG.

No good pictures to post. It has pretty much just remained very light snow/flurries for most of the afternoon with no significant accumulation. The only noticeable difference is that there is now a thin glaze of ice on the cars, and I slipped a few times on an icy sidewalk a little early (mostly due to the freezing drizzle that has been mixing in from time to time). It looks like the best accumulations will be remaining to my north, with 1-3" reported across north and northwest Oklahoma.

EDIT: It does look kind of like we might get grazed by the band coming in from the west. Might be enough to put down a quick dusting. I will post pictures if it does.

[Extremeweatherguy]

NWS in Norman looks excited about next week...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
309 PM CST TUE DEC 9 2008

.DISCUSSION...
AFTER FIRST HALF OF TONIGHT QUIETER WX ANTICIPATED FOR SECOND HALF
OF WEEK INTO THE WEEKEND. HOWEVER BEFORE WE GET THERE SOME WINTRY WX
EXPECTED THIS EVENING.

SHOULD SEE A GRADUAL SHIFT IN PRECIP FROM NORTHWEST TO SOUTHEAST
THIS EVENING ALONG WITH A SIMILAR SHIFT IN PRECIP TYPE. AS UPPER LOW
CONT TO MOVE SOUTH ACROSS TX... COLUMN WILL COOL AND MOISTEN FOR
LIGHT SNOW TO BECOME DOMINATE PRECIP TYPE THROUGH I-44 CORRIDOR WITH
PATCHY LIGHT FREEZING DRIZZLE FARTHER SOUTH. AMOUNTS EXPECTED TO
REMAIN VERY LIGHT AND SHOULD QUICKLY END LATER THIS EVENING WITH
CLEARING FROM WEST TO EAST DURING THE SECOND HALF OF THE NIGHT. WILL
FOR NOW LET WWA EXPIRE AT 6 PM AND LET EVENING SHIFT DECIDE IF ANY
EXTENSION IS NEEDED.

AFTER A COLD NIGHT SOME WARMING TOMORROW... ESPECIALLY SOUTHWEST.
MORE SUBSTANTIAL WARMING TREND THEN COMMENCES THURSDAY INTO THE
WEEKEND. WARM AND WINDY CONDTIONS OVER THE WEEKEND WILL ONCE AGAIN
RAISE WILDFIRE CONCERNS.

STILL QUITE A BIT OF UNCERTAINTY DURING THE LATTER PERIODS... AFTER
GFS AND ECMWF COMING MORE IN-LINE YESTERDAY AFTN. MORNING GFS DOES
NOT APPEAR TO WANT TO BRING ARCTIC AIR SOUTH THROUGH THE SOUTHERN
PLAINS EARLY NEXT WEEK AS IT HANGS UP ACROSS NORTHERN OK AND THEN
RETREATS BACK NORTH. DO NOT SEE THIS HAPPENING. ONCE IT BEGINS ITS
JOURNEY SOUTH NOT MUCH SHOULD STOP IT FROM MOVING ON SOUTH THROUGH
THE AREA. IT SHOULD THEN STICK AROUND FOR AT LEAST FOR A COUPLE OF
DAYS. THIS IS PROBLEMATIC AS SOUTHWEST FLOW ALOFT DEVELOPS ALLOWING
WAA UP OVER THE TOP OF VERY COLD ARCTIC AIR. THIS COULD LEAD TO
PERIODS OF FREEZING RAIN TO OCCUR ACROSS THE AREA BEGINNING ON
MONDAY AND CONTINUING TUESDAY AND POSSIBLY INTO WED... THE LATEST 12Z
ECMWF VERIFIES THIS POSSIBILITY.

Sunday Night: A 20 percent chance of rain. Mostly cloudy, with a low around 26.

Monday: A 20 percent chance of showers. Mostly cloudy, with a high near 36.

Monday Night: A slight chance of freezing rain. Mostly cloudy, with a low around 25. Chance of precipitation is 20%.

Tuesday: A slight chance of freezing rain. Cloudy, with a high near 29.

[Extremeweatherguy]

I just read JB's latest post, and he thinks the front next Monday may bring OKC temperatures that are 10-degrees colder than they were here this afternoon! If he is right, then we would be talking about daytime readings in the teens! Brr! He also thinks ice/snow problems could be in the works for us as well.

[Extremeweatherguy]

00z GFS is showing a 1050mb+ high pressure area coming into the northern plains next Monday...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_138l.gif

...looks like the model might be slowly starting to catch on.

UPDATE: In the end this run still winds up being too slow with the arctic air and continues to try and stall it in Texas. It is definitely an improvement over previous runs, but it is no where near perfect (yet).