Area forecast discussion updated at 9:09 p.m., from the National Weather Service, Norman

AREA FORECAST DISCUSSION…UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
909 PM CST WED FEB 20 2013

…WINTER STORM WITH HEAVY SNOW WILL AFFECT NORTHERN
OKLAHOMA LATE TONIGHT INTO THURSDAY…

.UPDATE…
REMOVED LOCATIONS SOUTHEAST OF A CHICKASHA TO MOORE TO
CHANDLER LINE FROM THE WINTER WEATHER ADVISORY.

EXTENDED THE WINTER STORM WARNING AND WINTER WEATHER
ADVISORY UNTIL 6 PM THURSDAY NORTH OF A CHEYENNE TO
ENID TO PERRY LINE.

———

.DISCUSSION…
WINTRY WEATHER AND SEVERE WEATHER POTENTIAL REMAIN THE
BIGGEST CHALLENGES. FORECAST REMAINS VERY COMPLICATED.

REMOVED THE LOCATIONS MENTIONED ABOVE FROM THE WINTER
WEATHER ADVISORY THINKING CHANCES OF ANY WINTRY
PRECIPITATION ACCUMULATIONS APPEAR TO VERY LOW BASED
ON LATEST HRRR/NAM12 DATA INDICATING A WARM NOSE OF AIR
+5 TO +10C AT 800 MB WHICH WOULD KEEP EVERYTHING LIQUID
IN THESE AREAS.

THOUGHT ABOUT REMOVING OKLAHOMA COUNTY FROM THE WINTER
WEATHER ADVISORY DUE TO DECREASING CONFIDENCE THAT
ADDITIONAL SNOW OR SLEET ACCUMULATIONS WILL BE ONE INCH
OR GREATER OR THAT FREEZING RAIN WILL OCCUR AT ALL WITH
SURFACE TEMPERATURES JUST ABOVE FREEZING…32 DEGREES.
HOWEVER…THERE DOES APPEAR TO BE A SMALL WINDOW CENTERED
AROUND 8 OR 9 AM FOR A QUICK INCH OF SNOWFALL.

HEAVY SNOWFALL OF 3 TO 6 INCHES WITH LOCALLY HEAVIER AMOUNTS
APPEARS TO BE A GOOD BET LATE TONIGHT INTO THURSDAY ACROSS
NORTHERN OKLAHOMA…ESPECIALLY NORTHWEST OF AN ARNETT TO
WOODWARD TO ALVA LINE…CLOSER TO MID LEVEL LOW. EXTENDED
HAZARD DURATION 6 HOURS ACROSS NORTHERN OKLAHOMA DUE TO
A SLOWER DEPARTURE OF THE APPROACHING MID/UPPER LOW.

FREEZING RAIN POTENTIAL TONIGHT INTO THURSDAY MORNING
APPEARS TO BE RATHER LOW DUE TO SURFACE WET BULB TEMPERATURES
GENERALLY IN THE 32 TO 37 DEGREE RANGE AND WITHOUT
SIGNIFICANT COLD AIR ADVECTION AT THE SURFACE. TEMPERATURES
WILL BE NEARLY STEADY FOR THE REST OF TONIGHT INTO
THURSDAY MORNING.

THE NEXT ROUND OF PRECIPITATION IS EXPECTED TO BEGIN
SOMEWHERE ACROSS FAR WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS 11 PM TO 1 AM. THIS PRECIPITATION WILL MAINLY BEGIN
AS RAIN…THEN SHOULD CHANGEOVER TO SNOW ACROSS NORTHWEST
OKLAHOMA. PRECIPITATION RATES MAY BE RATHER HIGH DUE TO
STRONG FORCING AND SOME ELEVATED INSTABILITY.

REGARDING SEVERE THUNDERSTORM POTENTIAL…A FEW STORMS
MAY CONTAIN HAIL UP TO THE SIZE OF QUARTERS DUE TO INCREASING
ELEVATED INSTABILITY…MAINLY OVER FAR SOUTHERN OKLAHOMA AND
WESTERN NORTH TEXAS MIDNIGHT TO 7 AM. WIDESPREAD SEVERE
APPEARS UNLIKELY.

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