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000
FXUS64 KTSA 052254
AFDTSA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
454 PM CST THU DEC 5 2013

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 0Z TAFS... WINTRY PRECIP MAINLY IN THE FORM OF FREEZING
RAIN IN THE SOUTH TO SLEET AN SNOW IN THE NORTH WILL PREVAIL AT
ALL SITES THROUGH MOST OF THE 24 HOUR FORECAST PERIOD. MVFR
CONDITIONS WILL GENERALLY PREVAIL AT ALL SITES... WITH
INTERMITTENT IFR CONDITIONS LIKELY WITH HEAVIER PRECIPITATION
BANDS. CONDITIONS WILL BEGIN TO IMPROVE FROM THE NORTH DURING THE
AFTERNOON FRIDAY.



&&

.PREV DISCUSSION... /ISSUED 420 PM CST THU DEC 5 2013/

DISCUSSION...

***WINTER WEATHER IMPACTS ARE ONGOING ACROSS EASTERN OKLAHOMA AND
 NORTHWEST ARKANSAS...AND SOME WILL BE SIGNIFICANT BY EVENTS END***

THE WELL TALKED ABOUT EVENT FOR THE BETTER PART OF A WEEK IS NOW
UNDERWAY. THE STAGE HAS BEEN SET...SUB-FREEZING ARCTIC AIR IS IN
PLACE...AND HAS UNDERCUT A STRONG SOUTHWESTERLY JET ALOFT
DOWNSTREAM FROM A DEEP WESTERN CONUS UPPER TROUGH. THE INCREASING
LOW-MID LVL FRONTOGENESIS AND ISENTROPIC LIFT HAS PRODUCED A
CONSISTENT SWATH OF PRECIPITATION THAT STRETCHES FROM NORTHERN TX
ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. SNOW AND SLEET ARE
PREDOMINANT NORTH AND WEST...WITH SLEET AND FREEZING RAIN
PREDOMINANT ACROSS THE SOUTH AND EAST AS A WARM LAYER IS
MAINTAINED BY THE SOUTHWEST FLOW ALOFT. SOME SLEET/SNOW ACCUMULATION
HAS ALREADY OCCURRED ACROSS NORTHEAST OKLAHOMA AND SOME ICING HAS
BEEN REPORTED IN THE SOUTHEAST...AND IS ALSO NICELY EVIDENT IN THE
MESONET CURRENT WIND SPEED PLOTS...AS THE ANEMOMETERS FREEZE UP.

ROUND TWO IS FORECAST BY THE MODELS TO BEGIN LATER THIS
EVENING...WITH THE BULK OF THE ACTIVITY AFTER MIDNIGHT. THIS WILL
BE IN RESPONSE TO THE APPROACHING SHORTWAVE TROUGH OVER THE
SOUTHWEST CONUS. A NICE BAND OF PRECIP WILL SET UP ALONG THE MID
LVL DEFORMATION ZONE FROM EAST CENTRAL-NORTHEAST OK UP INTO
NORTHWEST AR. GENERALLY...3 TO 6 INCHES OF SNOW/SLEET ACCUMULATION
IS EXPECTED BY FRIDAY MORNING...WITH SOME LOCALLY HIGHER AMOUNTS
IN NORTHWEST ARKANSAS. THUS...A WINTER STORM WARNING WILL REMAIN
IN EFFECT FOR NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS. THE
HEAVIEST BAND OF PRECIP WILL CONTINUE TO FOCUS FROM NORTHERN TX UP
ACROSS SOUTHEAST OK AND INTO WEST CENTRAL AR. TEMP PROFILES STILL
SUGGEST THAT THE WARM LAYER WILL BE DEEP ENOUGH AND THE SURFACE
COLD LAYER WILL NOT BE DEEP ENOUGH TO PREVENT LIQUID FROM REACHING
THE GROUND FOR MUCH OF THE NIGHT. AS A RESULT...SIGNIFICANT ICE
ACCUMULATION IS STILL EXPECTED...WITH A GOOD HALF INCH
POSSIBLE...WITH SOME LOCALLY HEAVIER AMOUNTS NEAR THE RED RIVER
AND HIGHER TERRAIN. SIGNIFICANT IMPACTS TO TRAVEL AND THE POWER
GRID ARE LIKELY IN THIS AREA...AND FOR THAT REASON AN ICE STORM
WARNING WILL REMAIN IN EFFECT. ANOTHER COUPLE INCHES OF SLEET AND
SNOW COULD ALSO FALL IN THE ICE STORM WARNING AREA FRIDAY MORNING.
THE PRECIP WILL COME TO A RAPID END FROM WEST TO EAST DURING THE
DAY FRIDAY AS THE WAVE MOVES ACROSS.

INCREASING LIFT FROM THE NEXT WAVE WILL BRING CHANCES OF LIGHT
PRECIPITATION OVER THE WEEKEND...MAINLY SATURDAY NIGHT INTO
SUNDAY. MOISTURE WILL BE LIMITED AS THE BEST MOISTURE WILL BE
SHUNTED WELL TO THE SOUTH AND EAST WITH THE SURFACE FRONT. LAYER
TEMP PROFILES SUGGEST MAINLY SNOW OR SLEET...BUT MODEL SOUNDINGS
ALSO SHOW DRYING OUT ALOFT IN THE -10C TO -15C LAYER...AND
SATURATION BELOW 700MB...THUS THE POTENTIAL FOR PATCHY FREEZING
DRIZZLE EXISTS AS SURFACE TEMPS REMAIN BELOW FREEZING DURING THIS
TIME. THE LIFT SHUTS OFF BY SUNDAY EVENING AS THE SYSTEM LIFTS OFF
TO OUR NORTH.

THE WESTERN TROUGH FINALLY EJECTS OUT OF THE WEST AND THE PATTERN
DEAMPLIFIES TOWARD THE MIDDLE OF NEXT WEEK. UNTIL THEN...THIS
HIGHLY AMPLIFIED UPPER PATTERN OVER THE EASTERN PACIFIC AND NORTH
AMERICA AND THE RESULTING CROSS POLAR FLOW WILL CONTINUE TO SEND
REINFORCING SURGES OF ARCTIC AIR INTO OUR REGION. LOWS ON SATURDAY
MORNING AND TUESDAY MORNING COULD DROP TO NEAR ZERO OR BELOW ZERO
OVER A SNOWPACK...WITH WIND CHILLS BELOW -10. BRRRRR. AREAS THAT
HAVE POWER OUTAGES FOR AN EXTENDED TIME WILL HAVE CONCERNS WITH
THE COLD.

LACY

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...ICE STORM WARNING UNTIL 6 PM FRIDAY FOR OKZ049-OKZ053-OKZ072-
     OKZ073-OKZ074-OKZ075-OKZ076.

     WINTER STORM WARNING UNTIL 6 PM FRIDAY FOR OKZ054-OKZ055-OKZ056-
     OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-
     OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-OKZ071.

AR...WINTER STORM WARNING UNTIL 6 PM FRIDAY FOR ARZ001-ARZ002-ARZ010-
     ARZ011.

     ICE STORM WARNING UNTIL 6 PM FRIDAY FOR ARZ019-ARZ020-ARZ029.

&&

$$

SHORT TERM...99
LONG TERM....99
AVIATION...06