FXUS64 KOUN 012018
AFDOUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
218 PM CST TUE DEC 1 2009
.UPDATE...
UPDATED FORECAST TO REFLECT THE POSSIBILITY OF LIGHT SLEET BEING
MIXED WITH THE RAIN ACROSS PARTS OF SOUTHERN OK AND WESTERN N-TX
FOR THE REMAINDER OF THE AFTERNOON. A FEW PIXELS OF 50 DBZ
REFLECTIVITIES SHOWING UP ON RADAR LIKELY INDICATE A LITTLE SLEET
MIXED IN WITH THE RAIN. SPS REPORTED SLEET FOR A SHORT BIT
EARLIER THIS AFTERNOON. WITH SURFACE TEMPERATURES WELL ABOVE
FREEZING THERE WILL BE NO ICING PROBLEMS. ALSO NUDGED HIGHS A FEW
DEGREES WARMER IN FAR NORTHWEST OK.
&&
.PREV DISCUSSION... /ISSUED 1154 AM CST TUE DEC 1 2009/
AVIATION...
MODEL FORECASTS DIFFER MARKEDLY IN CEILING HEIGHT AND VISIBILITY
FOR THE OVERNIGHT PERIOD...ESPECIALLY AT KOKC/KOUN/KCSM/KHBR. LOW
LEVELS OF THE ATMOSPHERE ARE FAIRLY DRY AND WILL TAKE SOME TIME TO
MOISTEN. THE UPPER LOW RESPONSIBLE FOR CLOUDS AND PRECIP WILL MOVE
RAPIDLY TO THE EAST/NORTHEAST. ADDITIONALLY...DRY AIR WILL MOVE
INTO OKLAHOMA AND EVENTUALLY NORTH TEXAS BEHIND A COLD FRONT EARLY
TOMORROW MORNING. THE OPTIMISTIC TAFS WERE WRITTEN WITH THIS IN
MIND...BUT THERE IS A CHANCE THAT LOW CEILINGS WED MORNING COULD
DEVELOP A LITTLE FURTHER NORTHWARD THAN FORECAST.
TAYLOR
PREV DISCUSSION... /ISSUED 1047 AM CST TUE DEC 1 2009/
UPDATE...
WILL SLOW THE SPREAD OF RAIN ACROSS N-TX AND CENTRAL/SW OK FOR THE
REMAINDER OF THE DAY AS IT IS WILL TAKE A LITTLE MORE TIME TO
MOISTEN UP THE DRY AIRMASS OVER THE REGION. WILL ALSO SLOW THE
ADVANCEMENT OF CLOUDS ACROSS THE NORTHERN HALF OF OK. BUMPED UP
WIND SPEEDS A LITTLE MORE QUICKLY OVER NW OK AS GUSTS TO NEAR 25
MPH ALREADY SHOWING UP ON THE OK MESONET. ALSO RAISED TEMPS A COUPLE
DEGREES IN FAR NW OK.
PREV DISCUSSION... /ISSUED 529 AM CST TUE DEC 1 2009/
AVIATION...
MID LEVEL CEILINGS ARE SPREADING INTO THE SOUTHWESTERN TAF SITES
/KSPS KLAW KHBR KCSM/ ALTHOUGH THE INITIAL ROUND OF RAIN CURRENTLY
OCCURRING IN WEST TEXAS WILL MAINLY STAY WEST OF THESE AIRPORTS.
RAIN CHANCES WILL INCREASE ACROSS THE SOUTHWESTERN SITES TODAY
AND SPREADING INTO CENTRAL OKLAHOMA SITES /KOUN KOKC/ THIS
EVENING AHEAD OF THE UPPER LEVEL STORM SYSTEM THAT WILL TRACK
ACROSS TEXAS TODAY AND TONIGHT. INITIALLY CIGS GENERALLY WILL BE
VFR ALTHOUGH LIKELIHOOD OF MVFR CIGS WILL INCREASE OVERNIGHT IN
THE SOUTHWEST... WITH SOME CHANCE OF IFR CIGS WITH SOME OF THE
RAIN AREAS LATE TONIGHT.
PREV DISCUSSION... /ISSUED 405 AM CST TUE DEC 1 2009/
DISCUSSION...
PRECIP IS EXPANDING ACROSS WEST/SOUTHWEST TEXAS THIS MORNING AHEAD
OF UPPER LOW MOVING INTO CHIHUAHUA... AND MAIN ISSUE WITH THIS
FORECAST IS THE PRECIPITATION ASSOCIATED WITH THIS STORM AS IT
MOVES ACROSS TEXAS. MODELS HAVE BEEN TRENDING TOWARD KEEPING THE
NORTH END OF THE PRECIP SHIELD FARTHER SOUTH... SO ALTHOUGH
PRECIPITATION IS ALMOST CERTAIN ACROSS NORTH TEXAS AND SOUTHERN
OKLAHOMA IT IS UNCLEAR WHERE THE NORTHERN END OF THIS PRECIP WILL
BE. BUT THE 00Z MODELS DID NOT HAVE THE PRECIPITATION SIGNAL AS
FAR NORTH AS IS CURRENTLY OCCURRING BETWEEN MIDLAND AND LUBBOCK
THIS MORNING. HAVE DECREASED POPS SOMEWHAT ACROSS THE CENTRAL AND
NORTH TODAY THROUGH TOMORROW BUT HAVE KEPT POPS AT THE HIGH SIDE
OR ABOVE CURRENT GUIDANCE RANGE. NEXT QUESTION IS PRECIP TYPE AS
MODELS ARE KEEPING LOW LEVEL TEMPERATURES WARMER THAN PREVIOUSLY
INDICATED. BUFR SOUNDINGS SHOW THAT MANY AREAS WILL HAVE A LARGE
ENOUGH AREA OF NEAR-SURFACE TEMPERATURES ABOVE 0C THAT THE
MIX/CHANGE TO SNOW IS MORE IN QUESTION. COOLER LOW-LEVEL
TEMPERATURES FROM THE NORTH WILL BE LATE TO ARRIVE ALTHOUGH THE
SOUTHWESTERN STORM SYSTEM WILL BRING A COOLER COLUMN WITH IT. WILL
MAINTAIN THE CHANCE OF RAIN/SNOW MIX IN THE PACKAGE BUT WILL USE
LOWER SNOW PROBABILITY WORDING... ESPECIALLY IN CENTRAL OKLAHOMA
WHERE LOW-LEVEL TEMPERATURES ARE EXPECTED TO BE WARMER BETWEEN THE
COLDER TEMPERATURES ADVECTING INTO THE NORTH AND THE COOLER COLUMN
CLOSER TO THE STORM SYSTEM TO THE SOUTH.
LOOKING FARTHER AHEAD... THE NORTHERN STREAM TROF EXTENDING
SOUTHWEST FROM THE GREAT LAKES BEGINS TO AFFECT THE PLAINS MORE
AFTER THIS SOUTHWESTERN SYSTEM MOVES NORTHEAST... AND MODELS ARE
DEVELOPING SOME QPF ACROSS THE SOUTHWEST/SOUTH ON THURSDAY NIGHT
AND FRIDAY AS THIS TROF AXIS PIVOTS THROUGH THE AREA. HAVE ADDED
SLIGHT CHANCE POPS BUT WILL NOT BE AS AGGRESSIVE AS SOME OF THE
MEX POPS NUMBERS YET. BELOW AVERAGE TEMPERATURES ARE EXPECTED TO
CONTINUE THROUGH THE FORECAST PERIOD AND ANOTHER COLD FRONT MOVES
INTO THE AREA ON SUNDAY. .26.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 35 44 26 43 / 50 30 0 10
HOBART OK 33 46 27 42 / 50 20 0 10
WICHITA FALLS TX 33 47 30 41 / 80 30 0 10
GAGE OK 27 43 20 36 / 20 10 10 10
PONCA CITY OK 35 44 23 39 / 30 10 0 10
DURANT OK 38 47 32 46 / 80 60 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
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