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000
FXUS64 KOUN 200959
AFDOUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
459 AM CDT MON MAY 20 2013

.DISCUSSION...
SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING WITH
VERY LARGE HAIL AND TORNADOES IS THE FORECAST CHALLENGE OF
THE DAY.

THROUGH 11 AM THIS MORNING...CAPPING SHOULD NOT ALLOW FOR
MUCH...IF ANY STORM DEVELOPMENT. LOCATIONS NEAR AND EAST OF
PONCA CITY HAVE THE BEST SHOT FOR AN ELEVATED STORM OR TWO.

CONFIDENCE IS HIGH THAT ANOTHER ROUND OF SIGNIFICANT SEVERE
THUNDERSTORMS WILL OCCUR THIS AFTERNOON INTO THIS EVENING IN THE
SPC MODERATE RISK AREA. THE ENVIRONMENT THIS AFTERNOON AND EVENING
WILL BE SIMILAR TO YESTERDAY WITH A FEW SUBTLE DIFFERENCES
INCLUDING SLIGHTLY LOWER LOW LEVEL HELICITY AND SHEAR VALUES AND
SLIGHTLY WEAKER CAPPING.

IT APPEARS THE HIGHEST CHANCE AREA FOR SEVERE STORMS THIS
AFTERNOON AND EVENING MAY BE A BIT FARTHER SOUTH THAN
YESTERDAY...PERHAPS NEAR A DUNCAN TO PAULS VALLEY TO SEMINOLE
LINE. THE OKLAHOMA CITY AREA MAY BE AFFECTED...PARTICULARLY THE
SOUTH SIDE INCLUDING NORMAN AND MOORE. FIRST STORMS MAY DEVELOP A
BIT EARLIER AS A RESULT OF SLIGHTLY WEAKER CAPPING...1 TO 3
PM...SOMEWHERE NEAR OR JUST EAST OF I-44 FROM LAWTON TO OKLAHOMA
CITY. BASED ON LATEST HRRR/MODEL GUIDANCE...STORMS WOULD LIKELY
BEGIN AS DISCRETE SUPERCELLS AND MAY REMAIN AS THIS STORM MODE...
THOUGH SOME MODELS HINT THAT STORMS MAY BECOME MORE LINEAR. LOW
LEVEL SHEAR IS FORECAST TO INCREASE SLOWLY THROUGHOUT THE
AFTERNOON WITH AN INCREASING CHANCE FOR TORNADOES...WHICH MAY
LARGE AND LONG LIVED. VERY LARGE HAIL WILL BE ANOTHER CONCERN WITH
ANY SUPERCELL. STORMS MAY DIMINISH OR MOVE INTO EASTERN OKLAHOMA
DURING THE EVENING HOURS AS THE LOW LEVEL JET VEERS TO THE
SOUTHWEST. THE CHANCES FOR SEVERE WILL DECREASE TONIGHT.

LOCATIONS NORTHWEST OF I-44 HAVE A MUCH LESS CHANCE FOR SEVERE
STORMS THROUGH TONIGHT. A FRONT NEAR A FREDERICK TO STILLWATER
LINE WILL MOVE VERY LITTLE THROUGH EARLY TUESDAY MORNING.
TEMPERATURES TODAY SHOULD BE A BIT COOLER THAN YESTERDAY IN
MOST LOCATIONS.

ON TUESDAY...THERE IS SOME POTENTIAL FOR SEVERE THUNDERSTORMS
ALONG AND SOUTH OF THE FRONT...MAINLY SOUTHEAST OF AN ARDMORE TO
ADA LINE...DURING THE AFTERNOON HOURS. DAMAGING WIND AND LARGE
HAIL MAY BE THE MAIN HAZARDS. CONFIDENCE OF SEVERE IS LOWER IN
THESE AREAS.

WEDNESDAY THROUGH SUNDAY...KEPT LOW CHANCES...20 TO 30 PERCENT
FOR STORMS DURING MOST PERIODS DURING THIS FRAME...THOUGH MID
LEVEL RIDGING SHOULD REDUCE STORM COVERAGE. A FEW SEVERE STORMS
ARE POSSIBLE NEARLY EACH DAY DUE TO MODERATE TO HIGH INSTABILITY
AND ABUNDANT LOW LEVEL MOISTURE. TEMPERATURES NEAR OR SLIGHTLY
BELOW AVERAGE ON WEDNESDAY ARE FORECAST TO BE ABOVE AVERAGE BY
THE WEEKEND.

MBS

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  85  64  77  58 /  30  50  30  10
HOBART OK         94  60  83  56 /  10  10  20  10
WICHITA FALLS TX  96  68  84  61 /  20  20  20  10
GAGE OK           84  53  83  48 /  20  10  10   0
PONCA CITY OK     83  60  78  53 /  20  40  20  10
DURANT OK         88  70  81  64 /  10  30  60  40

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&

$$

23/17