Severe Thunderstorm Warning 175, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
200 PM EDT SUN AUG 17 2003

POTENTIALLY ACTIVE EVENING IN STORE FOR PARTS OF FORECAST AREA. MSAS
ANALYSIS PAINTS BEST INSTABILITY AXIS FROM SOUTHERN PIEDMONT THROUGH
TRIANGLE AREA THEN NE INTO NORTHERN COASTAL PLAIN. MODIFIED 12Z GSO
SOUNDING SUGGEST CAPE VALUES BETWEEN 3000-3500 J/KG WITH WBZ VALUES
STILL RATHER HIGH (BUT LOWER THAN PAST FEW DAYS) AT 12.5K FT AGL.
SLIGHTLY MORE STABLE AIR FILTERING INTO TRIAD AT THIS TIME. UPPER JET
AND ASSOCIATED VORT CENTER OVER OH VALLEY DROPPING MORE S THAN SE SO
EXPECT MOST CONVECTIVE ACTIVITY ASSOCIATED WITH THIS FEATURE TO REMAIN
WEST OF CENTRAL NC. JETLET OBSERVED EXITING MD/DELAWARE AT THIS TIME
WHILE SHEAR AXIS MOVING SLOWLY SE OVER REGION.  EXPECT MAJORITY OF
CONVECTIVE ACTIVITY TO OCCUR OVER THE COASTAL PLAIN... SANDHILLS AND
SOUTHERN/EASTERN PIEDMONT EARLY THIS EVENING THEN DIMINISH. PREVIOUS
FORECAST UPDATE INCREASED POPS TO LIKELY IN THE SOUTH AND SO LITTLE
NEED TO CHANGE AT THIS TIME. ACROSS THE NORTH...MAY TAPER POPS FROM 50%
NORTHERN COASTAL PLAIN TO 30% IN THE NW PIEDMONT.

FOR MON-TUE... AIRMASS DRIES OUT AS FLOW BECOMES MORE NORTHERLY IN THE
MID/UPPER LEVELS. TAIL END OF VORT MAX THAT CROSSES VA MON AFTERNOON
AND EVENING PROGGED TO CROSS FORECAST ARES LATE MON/MON NIGHT WITH WEAK
SHEAR AXIS OVERHEAD TUE. DUE TO LIMITED MOISTURE AVAILABILITY...ANY
CONVECTION SHOULD BE SCATTERED AT BEST.  ETA MODEL SOUNDINGS DEPICT
DECENT MID LEVEL CAP MON/TUE BUT WITH STRONG SURFACE HEATING...CAP
COULD BE BROKEN. AT THIS TIME PLAN TO KEEP POPS IN THE 20-30% CATEGORY
MON AND TUE LATE AFTERNOON/EARLY EVENING.

BY WED...MID/UPPER LEVEL ANTI-CYCLONE W-NW OF REGION WITH LOW LEVEL
EASTERLY FLOW SHOULD RESULT IN A MORE STABLE AIRMASS.

LOW LEVEL THICKNESS/TEMP SCHEME COMPARABLE TO MOS TEMPS...SO WILL
DEVIATE LITTLE FROM MOS MAX/MIN TEMPS THROUGH WED.

THU-SUN...RETURN FLOW ON BACK SIDE OF SURFACE HIGH WILL REPLENISH
MOISTURE INTO ATMOSPHERE. TROUGH DEVELOPMENT THU AND LINGERS INTO
FRI/SAT. WILL MAINTAIN CHANCE POPS THU-SUN. WITH TEMPS CLOSE TO
SEASONAL NORMS.

.RAH...NONE.

WSS

NCZ007>011-021>028-038>043-073>078-083>086-088-089-181000-

HAZARDOUS WEATHER OUTLOOK...CORRECTION FOR EXPIRATION TIME
NATIONAL WEATHER SERVICE RALEIGH NC
612 AM EDT SUN AUG 17 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...TODAY

SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE AREA LATER TODAY.
THE COMBINATION OF SURFACE BOUNDARIES... UPPER LEVEL DISTURBANCES...
ABUNDANT MOISTURE AND AFTERNOON HEATING WILL LEAD TO STRONG
THUNDERSTORMS. SOME OF THE STORMS COULD REACH SEVERE LIMITS WITH
THE MAJOR THREAT BEING STRONG WINDS.

.DAYS TWO THROUGH SEVEN...

...ENTER DETAILS HERE...

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

RHJ

NCZ026-027-172215-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
516 PM EDT SUN AUG 17 2003

...STRONG THUNDERSTORMS WILL MOVE ACROSS CENTRAL TO NORTHEAST
FRANKLIN AND MUCH OF NASH COUNTY THROUGH 615 PM EDT...

AT 515 PM EDT... DOPPLER RADAR INDICATED STRONG THUNDERSTORMS FROM
CENTERVILLE TO AVENTON TO NEAR ARCOLA. FREQUENT LIGHTNING AND HEAVY
RAIN WERE OCCURRING OVER THESE AREAS. THE THUNDERSTORMS WERE MOVING
SLOWLY TO THE SOUTHEAST AT 15 MPH.

ADDITIONAL THUNDERSTORMS WERE EXPECTED TO DEVELOP EAST OF THE
LOUISBURG AREA AND MOVE SOUTHEAST ACROSS EASTERN FRANKLIN AND NASH
COUNTY. THIS INCLUDES THE CASTALIA TO RED OAK AND POSSIBLY AS FAR
SOUTH AS NASHVILLE.

FREQUENT LIGHTNING... HEAVY RAIN... AND GUSTY WIND TO 30 MPH CAN BE
EXPECTED WITH THESE STORMS. WHEN THUNDER IS HEARD... GET AWAY FROM
WATER INCLUDING SWIMMING POOLS. MOVE OFF OF OPEN FIELDS AND INTO A
SAFE SHELTER.

BADGETT