Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 180645
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
245 AM EDT SAT APR 18 2015

.SYNOPSIS...HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTH
TODAY... THEN SHIFT SLOWLY OFFSHORE SUNDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH. THE WARM FRONT WILL MOVE NORTH ON SUNDAY
NIGHT. THIS WILL BE FOLLOWED BY A COLD FRONT THAT WILL PUSH WEST TO
EAST ACROSS CENTRAL NORTH CAROLINA LATE MONDAY INTO MONDAY EVENING.
&&

.NEAR TERM /TONIGHT/...
AS OF 950 PM FRIDAY...

A WELL-DEFINED SHORTWAVE TROUGH OVER NORTHERN AL/GA WILL MOVE
GENERALLY EAST ACROSS THE SOUTHERN APPALACHIANS...SC...AND FAR
SOUTHERN NC TONIGHT...TO A POSITION INVOF KILM BY 12Z SAT. AN
EXPANSIVE AREA OF SHOWERS WILL ACCOMPANY THIS FEATURE AS IT MOVES
EAST...WITH THE ASSOCIATED HIGHEST PROBABILITY OF RAIN OVER THE
SOUTHERN PIEDMONT/SANDHILLS/SOUTHERN COASTAL PLAIN AFTER
MIDNIGHT...WITH PROGRESSIVELY LOWER CHANCES TOWARD AND ESPECIALLY
NORTH OF HIGHWAY 64. IT APPEARED THAT A COUPLE UPSTREAM  CONVECTIVE
CLUSTERS OVER VA...WHICH INITIATED ALONG A LEE SURFACE TROUGH...MAY
MAINTAIN INTENSITY AS THEY PROPAGATED SOUTHEASTWARD ALONG THEIR
ASSOCIATED OUTFLOW INTO A WEAK INSTABILITY AXIS CENTERED OVER THE
NORTHERN NC PIEDMONT...BUT THAT ACTIVITY HAS MOSTLY DIMINISHED
DURING THE PAST FEW HOURS. SO WHILE A SHOWER OR TWO CANNOT BE
ENTIRELY RULED OUT OVER THE NORTHERN PIEDMONT AS BOTH PAIR OF
OUTFLOW DRIFT SOUTH...THE PROBABILITY OF OCCURRENCE IS QUITE LOW
RELATIVE TO THE INCOMING SHOWERS ASSOCIATED WITH THE AFOREMENTIONED
SHORTWAVE TROUGH. LOWS CLOSE TO CURRENT SURFACE DEWPOINT
TEMPERATURES...MOSTLY IN THE LOWER TO MIDDLE 60S. IF ANY APPRECIABLE
BREAKS IN THE CLOUDS OCCUR...MOST LIKELY OVER THE NORTHERN PIEDMONT
WHERE INFLUENCE FROM THE SHORTWAVE TROUGH AND ASSOCIATED
LIFT/MOISTURE WILL BE LESS PREVALENT...THEN PATCHY FOG WOULD BE
PROBABLE IN THOSE AREAS.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 300 PM FRIDAY...

SHOWERS WILL LINGER IN THE MORNING...ESPECIALLY IN THE SOUTHEAST...
AS THE SHORT WAVE MOVES OFFSHORE. COOL AIR ADVECTION IN NORTHEAST
FLOW WILL PROVIDE AN ISENTROPIC SURFACE TO INDUCE WEAK LOW LEVEL
FORCING IN THE SOUTH. MEANWHILE...UPPER RIDGING TRANSITIONS ACROSS
THE AREA DURING THE AFTERNOON TO EARLY OVERNIGHT...WHICH SHOULD BE
ANOTHER AID TO LIMITING CONVECTION LARGELY TO THE SOUTHERN TIER IN
THE AFTERNOON. WILL HAVE CHANCE POPS ACROSS THE FAR SOUTH TO SLIGHT
CHANCE ELSEWHERE. HIGHS WILL HAVE TO BE TONED DOWN DUE TO INCREASING
CLOUD COVERAGE AND WEAK COOL AIR ADVECTION. THICKNESSES SUPPORT A
COUPLE OF DEGREES EITHER SIDE OF 80.

THE UPPER RIDGING SHOULD DAMPEN ACTIVITY OVERNIGHT...BUT A WARM
FRONT WILL BE LIFTING NORTH...WITH H85 FLOW VEERING TO
SOUTHEAST...UPSLOPE...AND INCREASING. EXPECT PARTLY CLOUDY ACROSS
THE NORTH...WITH MORE CLOUDINESS IN THE SOUTH OVERNIGHT...AND COULD
SEE SHOWERS MIGRATE INTO THE FAR SOUTHWEST PIEDMONT BY MORNING. MINS
WILL BE COOLER ACROSS THE NORTH...MID 50S...GRADUATED TO AROUND 60
ACROSS THE SOUTHERN TIER.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...

THE DEEP MOISTURE FLUX IS EXPECTED TO BE PUSHING EAST OF OUR REGION
BY 12Z/MONDAY. THE TIMING OF THE BACK EDGE OF THE MAIN SHIELD OF
WIDESPREAD RAIN IS STILL DIFFICULT TO PIN DOWN. USING THE ENSEMBLE
APPROACH... IT APPEARS THAT THE SIGNIFICANT WEATHER SHOULD BEGIN TO
CLEAR OUT BETWEEN 09Z-15Z OR SO FROM WEST TO EAST MONDAY MORNING.

ONCE THE MID LEVELS DRY OUT MONDAY... THE SW FLOW IN THE WARM SECTOR
SHOULD ALLOW FOR AT LEAST PARTIAL CLEARING DURING MONDAY AFTERNOON.
THIS WOULD SET US UP FOR SCATTERED CONVECTIVE DEVELOPMENT
PARTICULARLY ALONG THE PRE-FRONTAL TROUGH AND/OR COLD FRONT EXPECTED
TO ARRIVE LATE IN THE DAY AND DURING THE EVENING. THE LATEST
STATICAL MOS SUGGESTS HIGHS OF 75-80 IN THE NW RANGING TO POSSIBLY
85 IN THE SANDHILLS. THIS COMBINED WITH FORECAST DEW POINTS IN THE
MID 50S NW TO LOWER 60S COASTAL PLAIN WOULD YIELD MUCAPE VALUES OF
1500+ J/KG WITH 2000 J/KG POSSIBLE IN THE COASTAL PLAIN AND EASTERN
PIEDMONT. THE WINDS FROM THE SURFACE TO ALOFT WILL BECOME
UNIDIRECTIONAL FROM THE SW SUGGESTING THAT THE MAIN SEVERE WEATHER
MODE WOULD MOST LIKELY BE THE THREAT OF STRAIGHT LINE WIND GUSTS.
AFTER THE LULL IN THE POP MONDAY MORNING... WE WILL RAISE POP MONDAY
AFTERNOON AND EVENING INTO THE 40-50 PERCENT RANGE AND CONTINUE TO
HIGHLIGHT THE POTENTIAL FOR A COUPLE OF STRONG TO SEVERE
THUNDERSTORMS MONDAY AFTERNOON INTO THE EVENING.

FOR MONDAY NIGHT THROUGH FRIDAY... THE PATTERN WILL CHANGE BACK TO
ONE THAT IS MUCH DRIER AND COOLER WITH A PREDOMINATE NW FLOW ALOFT
OVER NC. A DRY COLD FRONT IS FAVORED TO PUSH SOUTH THROUGH NC ON
THURSDAY AFTERNOON OR NIGHT. THE TEMPERATURES SHOULD BE WARMEST
WEDNESDAY AND THURSDAY OUT AHEAD OF THE FRONT (70S)... AND COOL BACK
INTO THE 65-70 RANGE BY FRIDAY. LOWS SHOULD BE IN THE MID 40S TO MID
50S MUCH OF THE WEEK.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 123 AM SATURDAY...

VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT. HOWEVER... VFR TO
MVFR CIGS CAN BE EXPECTED TODAY. THERE IS A CHANCE OF MVFR VSBYS
THIS MORNING WITH A CHANCE OF SHOWERS MAINLY AT KFAY.

A WARM FRONT WILL MOVE NORTH OVER NC SUNDAY. THIS WILL LOWER CIGS
AND VSBYS SUNDAY AS RAIN ARRIVES FROM THE SOUTH DURING THE DAY. IFR
TO LIFR CIGS AND VSBYS WITH RAIN AND FOG ARE EXPECTED LATE SUNDAY
INTO SUNDAY NIGHT.

MONDAY... CIGS WILL BREAK OUT INTO VFR DURING THE MORNING. THERE IS
A CHANCE OF SHOWERS AND THUNDERSTORMS WITH THE COLD FRONT MONDAY
AFTERNOON AND EVENING.

THE OUTLOOK BEYOND MONDAY...
A RETURN TO VFR CONDITIONS IS EXPECTED MONDAY NIGHT THROUGH FRIDAY.



&&

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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...RAH
SHORT TERM...MLM
LONG TERM...BADGETT
AVIATION...BADGETT


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