FXUS62 KRAH 140827
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
325 AM EST FRI NOV 14 2008

.SYNOPSIS...
A WARM FRONT JUST SOUTH OF CENTRAL NORTH CAROLINA THIS MORNING WILL 
DRIFT NORTHWARD THIS AFTERNOON AND TONIGHT. A STRONG COLD FRONT WILL 
APPROACH FROM THE EAST TONIGHT AND CROSS THE AREA SATURDAY AFTERNOON.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 AM FRIDAY...

RATHER COMPLICATED FORECAST THROUGH TONIGHT. WHILE FAIRLY CERTAIN 
THAT ALL LOCATIONS WILL SEE RAIN DURING THE NEXT 24 HOURS...MAX 
TEMPS TODAY WILL DEPEND UPON A FEW FACTORS. ALSO...APPEARS TO BE AN 
INCREASE THREAT FOR SEVERE STORMS LATE TONIGHT INTO SATURDAY MORNING.

UPPER LEVEL LOW THAT FORMED THU OVER S TX WAS BEGINNING TO LIFT 
SLOWLY TO THE NE FROM THE UPPER TX COAST TOWARD THE DEEP SOUTH. THIS 
FEATURE HAS BEGUN TO ENHANCE THE LOW LEVEL JET...EVIDENCE BY 
INCREASE IN CONVECTIVE ACTIVITY OVER GA INTO SC. A STALLED BOUNDARY 
OVER THE COASTAL SECTIONS OF SC AND NC WILL SLOWLY LIFT NORTH-NW 
TODAY AND TONIGHT IN RESPONSE TO THE INCREASING SLY WINDS ALOFT. 
THIS SHOULD LEAD TO AREAS OF SHOWERS AND ISOLATED THUNDER TO OCCUR 
THIS MORNING OVER THE SOUTHERN COUNTIES OF CENTRAL NC. SHOWERS ARE 
EXPECTED TO INCREASE IN COVERAGE AND INTENSITY ACROSS THE ENTIRE 
REGION THIS AFTERNOON AS THE WARM MOIST AIR JUST ABOVE THE SURFACE 
CONTINUES TO OVERRUN THE SLOW MOVING WARM FRONT. MAY SEE SOME 
ADDITIONAL LIFT ALOFT THIS AFTERNOON SUPPLIED BY INCREASING 
300-250MB WINDS. PRECIP WATER VALUES PROGGED TO BE BETWEEN 1.75 TO 2 
INCHES LATER TODAY...WELL ABOVE NORMAL FOR THIS TIME OF YEAR. WILL 
MENTION LOCALLY HEAVY RAIN IN FORECAST TEXT WITH ACTIVITY EXPECTED 
THIS AFTERNOON AS WELL AS TONIGHT. 

MAX TEMPS TODAY HIGHLY DEPENDENT UPON NORTHWARD MOVEMENT OF WARM 
FRONT AND EXPECTED SHOWER COVERAGE. 07Z TEMPS CURRENTLY RUNNING NEAR 
OR SLIGHTLY ABOVE MOS GUIDANCE. BASED ON SURFACE LIFTED INDICES 
FIELD...APPEARS THAT WARM FRONT MAY ADVANCE AS FAR NORTH AS 
RZZ-RDU-ALBEMARLE BY LATE AFTERNOON. THUS POTENTIAL FOR A 15-20 
DEGREE RANGE IN MAX TEMPS ACROSS FORECAST AREA WITH LOWER 70S SE 
TO UPPER 50S/NEAR 60 NW. POSSIBILITY THAT TRIAD AREA WILL REMAIN IN 
THE 50S ALL DAY AND NOT REACH 60 UNTIL SUNSET OR A LITTLE LATER.

THERMODYNAMICS REMAIN QUITE STRONG TONIGHT AS LOW LEVEL JET 
INCREASES TO 45-50KTS WHILE 130KT+ UPPER LEVEL JET ENTERS THE DEEP 
SOUTH BY EARLY SATURDAY. THE UPPER TX LOW LIFTS NE TONIGHT/EARLY SAT 
AND SHEARS ACROSS THE REGION. THIS FEATURE WILL ACT TO COOL TEMPS A 
TAD ALOFT...RESULTING IN MID LEVEL LAPSE RATES APPROACHING 6 DEG 
C/KM. MEANWHILE...GULF WILL BE WIDE OPEN AND STRONG LOW LEVEL JET 
WILL PULL MOIST UNSTABLE AIR INTO REGION AFTER 00Z SAT...MORE SO 
AFTER 06Z SAT. THE FAVORABLE KINEMATIC WIND FIELD AND INCREASINGLY 
FAVORABLE THERMODYNAMICS SUGGEST A BETTER POTENTIAL FOR STRONG OR 
SEVERE STORMS DURING THE LATE NIGHT HOURS TONIGHT INTO EARLY 
SATURDAY. MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS OR 
ISOLATED TORNADOES ASSOCIATED WITH BOWING CONVECTIVE SEGMENTS OR 
ISOLATED SUPERCELLS. TEMPS OVERNIGHT WILL HOLD STEADY OR MAY 
ACTUALLY RISE A COUPLE OF DEGREES.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 320 AM FRIDAY...

THREAT FOR STRONG/SEVERE CONVECTION WILL PERSIST THROUGH SATURDAY 
MORNING THEN BEGIN TO DWINDLE FROM WEST-TO-EAST SATURDAY AFTERNOON 
AS CORE OF LOW LEVEL JET LIFTS N-NE. 850-700MB TROUGH DOES NOT CROSS 
REGION UNTIL 00-06Z SUN. DUE TO THIS SLOWER THAN EXPECTED 
PASSAGE...HAVE DELAYED ENDING OF SHOWERS AND DISSIPATION OF CLOUD 
COVERAGE 3-4 HOURS FROM PREVIOUS FORECAST. DELAYED FRONTAL PASSAGE 
SUGGEST MAX TEMPS SATURDAY SHOULD REMAIN MILD...ESPECIALLY EAST 
HALF. -WSS

SUNDAY INTO MONDAY... MID AND UPPER TROUGHS WILL MOVE THROUGH AREA 
SUNDAY AND BE OFFSHORE BY SUNDAY NIGHT. STRONG NORTHWEST TO WEST 
FLOW BEHIND THE TROUGH COULD RESULT IN A FEW CLOUDS MAINLY ACROSS 
THE NORTHERN BORDER. HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE 
WEST AND NORTHWEST... SETTLING OVER THE CENTRAL GULF COAST STATES 
MONDAY. HIGHS SUNDAY WILL RANGE FROM 53 (NW) TO 58 (SE). LOWS SUNDAY 
NIGHT WILL RANGE FROM 29 TO 35. HIGHS MONDAY WILL BE IN THE MID 50S 
TO AROUND 60. -RHJ

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...

MONDAY NIGHT INTO TUESDAY... A LOW PRESSURE CENTER WILL MOVE EAST 
FROM THE GREAT LAKES TO WELL OFF THE NORTH ATLANTIC COAST. THE 
COMBINATION OF THIS SYSTEM COMBINED WITH HIGH PRESSURE BUILDING EAST 
FROM THE WESTERN PORTION OF THE NATION... WILL RESULT IN A NORTHERLY 
FLOW OF AIR PUSHING SOME CLOUDINESS INTO CENTRAL NORTH CAROLINA 
THROUGH WEDNESDAY EVENING. LOWS MONDAY NIGHT WILL BE IN THE LOW TO 
MID 30S. HIGHS TUESDAY WILL BE IN THE UPPER 40S TO MID 50S. 

HIGH PRESSURE WILL PERSIST OVER THE AREA TUESDAY NIGHT THROUGH EARLY 
THURSDAY. A WEAK SURFACE BOUNDARY WILL MOVE THROUGH THE AREA 
THURSDAY MORNING THROUGH THE AFTERNOON... SPREADING CLOUDINESS 
ACROSS THE REGION AS IT MOVES EAST/SOUTHEAST. LOWS TUESDAY NIGHT AND 
WEDNESDAY NIGHT WILL BE IN THE MID 20S TO AROUND 30. HIGHS WEDNESDAY 
WILL BE IN THE 40S... AND IN THE 50S ON THURSDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...

THE SATURATED AIR MASS LESS IN THE WAKE OF A COLD FRONT WHICH IS 
CURRENTLY ACROSS EASTERN NORTH CAROLINA... HAS RESULTED IN LOW LEVEL 
CLOUDINESS AND IFR TO LIFR VISIBILITIES. LIFR CONDITIONS WILL 
PERSIST OVER THE TAF AREA THROUGH 13Z. 

VISIBILITIES WILL GRADUALLY LIFT TO MVFR/IFR DURING THE LATE MORNING 
TO EARLY AFTERNOON FROM SOUTHEAST TO NORTHWEST AS A WARM FRONT LIFTS 
NORTH THROUGH THE AREA AND RAIN REDEVELOPS OVER THE REGION... AND 
WINDS SHIFT TO THE SOUTH. 

IFR TO LIFR CONDITIONS WILL ONCE AGAIN OVERSPREAD THE AREA TONIGHT 
IN RAIN AND FOG. GUSTY WINDS WILL DEVELOP OVER THE AREA TONIGHT 
AHEAD OF AN APPROACHING COLD FRONT. SOUNDING DATA ALSO INDICATES 
STRONG WINDS ALOFT...JUST OFF THE SURFACE. LLWS WILL BE ADDED TO THE 
NEXT TAF ISSUE FOR SATURDAY MORNING WHERE WINDS AROUND 2 THOUSAND 
WILL BE AT LEAST 35 TO 40 KNOTS. 

CEILINGS WILL BE SLOW TO IMPROVE SATURDAY NIGHT INTO EARLY SUNDAY AS 
A STRONG NORTH TO NORTHWEST GRADIENT MAY ENHANCE SOME COLD AIR 
STRATOCU OVER THE REGION. VFR CONDITIONS WILL RETURN BY SUNDAY 
AFTERNOON AND CONTINUE THROUGH TUESDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ021>023-
038-039.

&&

$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS/RHJ
LONG TERM...RHJ
AVIATION...RHJ