Severe Thunderstorm Warning 199, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
245 PM EDT MON JUN 5 2006

.SHORT TERM /TONIGHT THROUGH THURSDAY/...

THROUGH TONIGHT: DESPITE LIMITED BOUNDARY LAYER MOISTURE... DYNAMIC
LIFT ASSOCIATED WITH THE INCOMING VORTICITY MAXIMUM WORKING ON A
WEAKLY UNSTABLE COLUMN HAS FORCED SCATTERED CONVECTION TO DEVELOP
OVER THE CWA... FOCUSED LARGELY ALONG THE DIFFUSE SURFACE DEWPOINT
GRADIENT. EXPECT THESE TO INCREASE IN COVERAGE OVER THE CENTRAL AND
EASTERN CWA WHERE MOISTURE AND INSTABILITY ARE BETTER... AND WHERE
MID LEVEL LAPSE RATES SHOULD STEEPEN AS THE MID LEVEL CLOSED LOW
DRIFTS OVERHEAD. WILL CONTINUE WITH CHANCE POPS FOR THE REST OF THE
AFTERNOON... HIGHEST EAST... THROUGH THIS EVENING. WITH LOW WET BULB
ZERO VALUES... WILL NEED TO WATCH FOR HAIL-PRODUCERS. WILL KEEP
CONSIDERABLE CLOUDS OVERNIGHT PARTICULARLY IN THE EAST HALF WITH THE
WEAK WIND FIELD AND LINGERING MOISTURE IN THE BOUNDARY LAYER. LOWS
54-58.

TUESDAY: THE MID LEVEL CLOSED LOW MEANDERS OVER EASTERN NC THROUGH
THE DAY WITH SURFACE CYCLOGENESIS NEAR OR OVER THE OUTER BANKS. AS
ONE MIGHT EXPECT... THE MODELS ARE IN DISAGREEMENT ON THE DETAILS...
BUT THEY BOTH INDICATE ENOUGH MOISTURE AND LOW LEVEL CONVERGENCE
WITH ONSHORE FLOW FOR SCATTERED SHOWERS AND STORMS... DESPITE
LIMITED INSTABILITY. THE GFS APPEARS TO HAVE CONVECTIVE FEEDBACK
ISSUES AND PREFER THE NAMS MORE CONSERVATIVE QPF. WILL RAISE POPS
TO HIGH CHANCES IN THE EAST... LOWER CHANCES IN THE WEST TUESDAY
THROUGH TUESDAY NIGHT. WITH GENERALLY MOSTLY CLOUDY SKIES... DONT
EXPECT TEMPERATURES TO BE THAT MUCH WARMER THAN TODAY. WILL HAVE
HIGHS 73-78... ON THE LOW END OF MOS GUIDANCE HIGHS.

TUESDAY NIGHT THROUGH THURSDAY: EXPECT LINGERING POPS IN THE EAST
TUESDAY NIGHT AS THE LOW MOVES FURTHER OFFSHORE AND LOW LEVEL FLOW
BACKS TO NORTHWESTERLY BY EARLY WEDNESDAY. THE GFS IS STICKING WITH
ITS SOLUTION OF ANOTHER WAVE DIVING FROM THE WESTERN GREAT LAKES
REGION SSE TO GA WEDNESDAY/THURSDAY... AND THE LAST COUPLE RUNS OF
THE NAM HAVE BOUGHT INTO THIS SOLUTION AS WELL. THIS SEEMS TO HAVE
MINIMAL IMPACT ON NC INTO THURSDAY... OTHER THAN A PERSISTENT WEAK
SURFACE TROUGH EXTENDING FROM THE SURFACE LOW OFF THE MIDATLANTIC
COAST BACK OVER THE CAROLINAS. COLUMN UNDERGOES GRADUAL DRYING WITH
SOME STABILIZATION IN THE MID LEVELS... AND WILL NOT CARRY POPS FOR
WEDNESDAY INTO THURSDAY... ALTHOUGH CONFIDENCE IN THIS IS NOT GREAT.
LATER FORECASTS MAY NEED TO ADD ISOLATED CONVECTION IF INSTABILITY
OR MOISTURE AVAILABILITY INCREASE. HAVE HELD TEMPERATURES PRETTY
CLOSE TO SEASONAL NORMALS BOTH DAYS... WITH HIGHS IN THE LOWER TO
MID 80S AND LOWS IN THE UPPER 50S TO LOWER 60S. -GIH

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

MID LEVEL TROUGH AXIS REMAINS SITUATED OVER NC THURSDAY NIGHT INTO
FRIDAY. WITH THE CANADIAN AND ECMWF BOTH SHOWING DECENT MID LEVEL
LAPSE RATES NEAR 6.5 C/KM AND POSITIVE VORTICITY ADVECTION WITH A
LAST-GASP WAVE DROPPING DOWN INTO THE TROUGH BASE... AND WITH BOTH
THE GFS AND ECMWF TAKING THE LEFT EXIT REGION OF A NORTHERLY JET
OVER THE AREA... WILL HOLD ONTO LOW CHANCE POPS MAINLY EAST THURSDAY
NIGHT AND FRIDAY. THEN THE MAIN STORY FOR SATURDAY THROUGH MONDAY
WILL BE THE BUILDING MID LEVEL RIDGING OVER THE DEEP SOUTH AND
SOUTHEAST STATES... AS THE TROUGH SHIFTS WELL OUT TO SEA AND AND NEW
TROUGHING DEVELOPS INTO THE NORTHERN PLAINS. WE MAY SEE A FEW
SHOWERS WITH WARM FRONTAL PASSAGE SATURDAY NIGHT OR EARLY SUNDAY...
BUT LATER FORECASTS CAN ADDRESS THIS MINOR RISK IF IT APPEARS
IMMINENT. 850 MB TEMPERATURES CLIMB TO 18+ DEGREES AND LOW LEVEL
THICKNESSES RISE TO 25-30 M ABOVE NORMAL INTO SUNDAY AND MONDAY...
AND WITH GOOD AGREEMENT AMONG THE MODELS ON THIS PATTERN... WILL
CARRY HIGHS IN THE UPPER 80S TO LOWER 90S SUNDAY AND 91-95 MONDAY...
WITH GENERALLY DRY WEATHER EXPECTED. -GIH

&&

.AVIATION...

CLOUDS BASES 35 HUNDRED TO 5 THOUSAND FEET THROUGH THE TAF PERIOD.
VISIBILITY UNRESTRICTED. NORTH TO NORTHEAST WINDS 10 TO 15 MPH
THROUGH AROUND MIDNIGHT...THAN LESS THAN 10 MPH.

UPPER LEVEL TROUGH MOVING THROUGH COMBINED WITH AFTERNOON HEATING
WILL LEAD TO THE DEVELOPMENT OF AFTERNOON AND EVENING THUNDERSTORMS.
THE STORMS WILL BE SCATTERED SO WILL ADD TO THE TAFS AS THEY
DEVELOP. THE STORMS SHOULD DISSIPATE WITH THE LOST OF HEATING. -RHJ

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...RHJ