Seymour, TX Special Weather Statement

HAZARDOUS WEATHER OUTLOOK

Issued:

306 PM CDT FRI SEP 5 2008

Expires:

700 AM CDT SAT SEP 06 2008

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN... CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS. .DAY ONE...REST OF THIS AFTERNOON AND TONIGHT... THUNDERSTORM OUTLOOK... THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING IN PART OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS. LOCATION... THE SLIGHT RISK INCLUDES THE AREA WEST OF A LINE FROM ALVA TO WEATHERFORD... TO MOUNTAIN VIEW...AND ALTUS OKLAHOMA... TO QUANAH TEXAS. TIMING... THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE THROUGH 11 PM. IMPACTS... SUPERCELLS WITH THE PRIMARY THREAT BEING LARGE HAIL UP TO GOLF BALL SIZE. MINOR...AND LOCALLY SIGNIFICANT DAMAGE TO ROOFTOPS... AUTOMOBILES...AND TENDER VEGETATION. SEVERE WIND GUSTS AROUND 60 MPH. A LOW CHANCE FOR A TORNADO. RECOMMENDED ACTIONS... STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS THROUGH 11 PM. DISCUSSION... A SURFACE LOW PRESSURE WAS LOCATED IN THE OKLAHOMA PANHANDLE AROUND MID-AFTERNOON... WITH A COLD FRONT EXTENDING ACROSS THE EASTERN TEXAS PANHANDLE INTO WEST TEXAS. AN OUTFLOW BOUNDARY FROM THE MORNING THUNDERSTORMS... ALSO EXTENDED FROM THE LOW PRESSURE SOUTHEASTWARD ACROSS WESTERN AND CENTRAL OKLAHOMA. SOUTHEASTERLY WINDS AT LOW AND MID LEVELS HAS INCREASED THE MOISTURE ACROSS PARTS OF WESTERN NORTH TEXAS AND WESTERN OKLAHOMA TODAY...WITH DEWPOINTS IN THE LOW 60S. MEANWHILE...A BROAD UPPER LEVEL TROUGH OVER THE PLAINS ALONG WITH A DISTURBANCE MOVING THROUGH THE TROUGH... WILL MAINTAIN COOL TEMPERATURES ALOFT...AND MODERATE WIND SHEAR... PROVIDING A FAVORABLE ENVIRONMENT FOR ORGANIZED THUNDERSTORM DEVELOPMENT. STRONG HEATING ALONG AND SOUTH OF THE BOUNDARIES HAS RESULTED IN MODERATE INSTABILITY THIS AFTERNOON OVER THE SLIGHT RISK AREA. SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP NEAR AND AHEAD OF THE BOUNDARIES IN THE EASTERN TEXAS PANHANDLE TOWARD WESTERN OKLAHOMA. STORMS WILL THEN MOVE EAST AND SOUTHEAST THROUGH THE EVENING. SUPERCELLS ARE EXPECTED... WHICH WILL INCREASE THE THREAT FOR LARGE HAIL IN PARTICULAR... WITH A SECONDARY THREAT FOR DAMAGING WINDS. RELATIVELY HIGH CLOUD BASES WILL KEEP TORNADO POTENTIAL VERY LOW... BUT AN ISOLATED TORNADO COULD OCCUR... ESPECIALLY WITH ANY STORM THAT TURNS MORE STRONGLY TOWARD THE SOUTH. THUNDERSTORMS WILL BECOME ELEVATED... WITH DECREASING INSTABILITY BY LATE EVENING. A LOW LEVEL JET COULD MAINTAIN STORMS OVERNIGHT... SPREADING INTO NORTH CENTRAL AND CENTRAL OKLAHOMA. THESE STORMS COULD PRODUCE LIGHTNING...SMALL HAIL...AND LOCALLY HEAVY DOWNPOURS. PROBABILITY TABLE... VALID THROUGH 700 AM CDT SATURDAY SEP 6. PROBABILITY OF THUNDERSTORMS OCCURRING IN THE NWS NORMAN COUNTY WARNING AREA...90 PERCENT. PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...60 PERCENT. OTHER HAZARDOUS WEATHER... NONE. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY... THUNDERSTORM OUTLOOK... A FRONTAL BOUNDARY AND UPPER LEVEL TROUGH WILL REMAIN IN THE REGION THROUGH MONDAY... MAINTAINING ISOLATED TO SCATTERED THUNDERSTORMS AT ANY GIVEN TIME. THE GREATEST CHANCE FOR STORMS WILL BE ALONG INTERSTATE 40 UP TO THE KANSAS BORDER... WITH LOWER CHANCES TOWARD THE RED RIVER. ISOLATED SEVERE STORMS ARE POSSIBLE DURING THIS TIME... ALTHOUGH AN ORGANIZED SEVERE WEATHER EVENT IS NOT EXPECTED. COOLER... SURFACE HIGH PRESSURE WILL REMOVE THE CHANCE FOR STORMS MONDAY NIGHT... BUT MOISTURE AND A FEW THUNDERSTORMS WILL RETURN BY THE MIDDLE OF NEXT WEEK. OTHER HAZARDOUS WEATHER... NONE. THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 7 AM SATURDAY.