Severe Thunderstorm Warning 60, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
122 PM EDT FRI JUN 22 2001

...WATCH UNTIL 7 PM LST WESTERN HALF...

MODELS HAVE INITIALIZED THE CURRENT SITUATION POORLY... HOWEVER ALL
POINT TO ACTIVITY ALONG THE FOOTHILLS THIS EVENING AND A FINGER OF
INSTABILITY/MOISTURE CONVERGENCE THAT EXTENDS FROM NEAR BOONE TO
AROUND LUMBERTON. THIS IS PUZZLING HOWEVER A CHECK OF THE WATER
VAPOR IMAGERY LENDS A CLUE. IF YOU LOOK AT CLOUDS ALONG THE
MOUNTAINS AND CLOUDS IN NORTH GEORGIA YOU CAN SEE THEM TURN
ANTICYCLONICALLY OVER NORTH CAROLINA. THE VORTEX OVER NORTH CENTRAL
NC IS AIDING CLOUDS AROUND ROXBORO THAT SHOULD MOVE INTO VIRGINIA.
THE VORTEX IS MARKED BY STRONG SUBSIDENCE ON THE IMAGERY. THE AREA
OF SUBSIDENCE IS NOT GETTING SMALLER BUT BEING OBSCURED BY THE HIGH
CLOUDINESS FROM THE NORTH GEORGIA CLOUDS. AS THE DRY AIR MOVES TO
THE NORTH AND VIRGINIA WE GET THE INCREASE IN MOISTURE CONVERGENCE
FROM BOONE TO LUMBERTON AREA. THUS LOOKS LIKE THIS EVENING
CONVECTION SHOULD BE IN THE SANDHILLS TO COASTAL PLAIN SOMEWHAT BUT
MAINLY THE WESTERN PIEDMONT AND FOOTHILLS.

TONIGHT LOOKS AS IF THE CONVECTION WILL MAKE THE WESTERN ZONES AND
WILL ONCE AGAIN MOVE FOR LIKELY POPS THEN THE FOCUS SHIFTS WITH THE
SURFACE FRONT TO THE EAST ON SATURDAY.

BY SATURDAY NIGHT AND SUNDAY THE AIR ABOVE 700 MB IS DRY AND DRYING.
MODELS ALL SEEM TO INDICATE THAT A CLOSED MID TO UPPER LEVEL LOW
WILL PULL LOW LEVEL MOISTURE AROUND IT BACK ACROSS CENTRAL NORTH
CAROLINA. THE AIR WILL BE SINKING DURING THIS TIME PERIOD AND MUCH
MORE STABLE. A VORTEX CAN BE SEEN IN THE WATER VAPOR IMAGERY OVER
MEMPHIS AT THIS TIME. THIS FEATURE HAS A LONG CYCLONIC SHEAR AXIS
EXTENDING ALONG THE GULF COAST. THIS FEATURE WILL NOT BE THE ONE
THAT CAUSES COULD BE IN NORTH GEORGIA ON SUNDAY HELPING TO WRAP
CLOUDS BACK INTO THE AREA... IT WILL TRACK NORTH OF THE PROJECTED
POSITION. THUS SOMETHING WOULD HAVE TO DEVELOP ALONG THE SHEAR AXIS
AND MOVE NORTHEAST TO NORTH GEORGIA BY SUNDAY. THUS WILL GO WITH
SLIGHT CHANCE OF SHOWERS ON SATURDAY NIGHT THROUGH SUNDAY AND CLOUDY
CONDITIONS.

EXTENDED...THERE IS A LACK OF UPPER LEVEL SUPPORT FOR THUNDERSTORMS
THROUGH THE EXTENDED PERIOD AS LONG WAVE RIDGE BUILDS OVER EASTERN
TWO THIRDS OF U.S. AND THE WESTERN ATLANTIC. MID-LEVEL CUT OFF LOW
COULD HELP TO DESTABILIZE UPPER LEVELS...BUT DEVELOPMENT AND
MOVEMENT OF THIS FEATURE REMAIN UNCERTAIN(WITH MEDIUM RANGE MODELS
DIFFERING IN THEIR SOLUTIONS). IN THE LOW LEVELS (SFC-850MB) WESTERN
ATLANTIC RIDGE BUILDS WESTWARD INTO NORTH CAROLINA...HELPING TO
MAINTAIN A WARM AND MOIST SOUTHERLY FLOW. THIS SHOULD BE ENOUGH~ TO
PRODUCE A FEW SHOWERS EACH AFTERNOON. IMPOSSIBLE TO FAVOR ONE DAY
OVER ANOTHER...SO A CHANCE WILL BE INCLUDED EACH DAY.

.RAH...SEVERE THUNDERSTORM WATCH UNTIL 7 PM LST WESTERN HALF OF
FORECAST AREA.

CLINE

NCZ007>010-021>026-038>041-073>076-083-084-222100-
ALAMANCE-ANSON-CHATHAM-DAVIDSON-DURHAM-FORSYTH-FRANKLIN-GRANVILLE-
GUILFORD-LEE-MONTGOMERY-MOORE-ORANGE-PERSON-RANDOLPH-RICHMOND-STANLY-
VANCE-WAKE-WARREN-

SEVERE WEATHER OUTLOOK FOR CENTRAL NORTH CAROLINA...UPDATED
NATIONAL WEATHER SERVICE RALEIGH NC
1100 AM EDT FRI JUN 22 2001

... THE THREAT FOR STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER THE PIEDMONT CONTINUES...

.SKYWARN SPOTTERS...
SKYWARN SPOTTER ACTIVATION IS NOT EXPECTED ACROSS CENTRAL NORTH
CAROLINA. HOWEVER...SPOTTERS ARE ENCOURAGED TO REPORT THREATENING
WEATHER OF ANY KIND TO THE NATIONAL WEATHER SERVICE.

.SYNOPTIC PATTERN...
A COLD FRONT ACROSS THE TENNESSEE VALLEY WILL MOVE SLOWLY EAST.
THE AIRMASS IN ADVANCE OF THE COLD FRONT ACROSS NORTH CAROLINA
IS MODERATELY MOIST AND UNSTABLE. WHEN THUNDERSTORMS DEVELOP A
SOUTHWESTERLY FLOW WILL PUSH ANY THUNDERSTORM ACTIVITY TOWARD
THE NORTHEASTWARD BETWEEN 10 AND 20 MPH.

.HAZARDOUS WEATHER DETAILS...
CLUSTERS OF SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AND FOOTHILLS LATER. THIS ACTIVITY WILL MOVE
NORTHEAST ACROSS PORTIONS OF THE PIEDMONT LATE THIS AFTERNOON AND
EVENING. THE MAIN AREA OF CONCERN IS THE WESTERN PIEDMONT OR AREAS
CLOSER TO THE FOOTHILLS.

WHILE THE WINDS ALOFT ARE NOT SUPPORTIVE OF WIDESPREAD SEVERE
THUNDERSTORMS...THE STRONGER STORMS WILL PRODUCE VERY HEAVY
RAIN...SMALL HAIL AND WIND GUSTS TO 45 MPH. THE GREATEST THREAT OF
SEVERE WEATHER WILL BE FROM 4 TO 8 PM.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

BLAES/CLINE