Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 061737 RRA
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
137 PM EDT WED MAY 6 2015

.SYNOPSIS...BERMUDA HIGH PRESSURE WILL PERSIST ACROSS THE AREA
THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL FORM NEAR THE BAHAMAS
AND MEANDER NEAR THE SOUTHEAST COAST THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...

A WEAK COLD FRONT WILL STALL...AND EVENTUALLY WASH OUT...OVER THE
VIRGINIAS TODAY. MEANWHILE TO OUR SOUTH-SOUTHEAST...MODELS ARE GOOD
AGREEMENT THAT THE DISORGANIZED CONVECTION NEAR THE BAHAMAS AND NW
CARIBBEAN ASSOCIATED WITH A BROAD UPPER TROUGH AND WEAK SFC TROUGH
WILL DEVELOP INTO A LOW PRESSURE AREA OVER THE NEXT 24 HOURS.

IN BETWEEN THESE TWO FEATURES...CENTRAL NC SHOULD REMAIN LARGELY
UNDER THE INFLUENCE OF A WEAKENING BERMUDA HIGH AND PERSISTENT
RIDGING ALOFT WHICH WILL SHOULD HELP MAINTAIN WARM AND MOSTLY DRY
CONDITIONS. THE EXCEPTION MAY BE ACROSS THE FAR NORTHERN ZONES...
NEAR THE NC-VA STATE LINE WHERE AN ISOLATED SHOWER OR TWO MAY
DEVELOP IN CLOSER PROXIMITY TO THE FRONT. HOWEVER...LACK OF MOISTURE
AND SUFFICIENT INSTABILITY WILL ACT TO SUPPRESS CONVECTIVE
DEVELOPMENT AND THUS WILL LEAVE OUT ANY RAIN CHANCES.

A PERSISTENCE FORECAST WILL BE DIFFICULT TO BEAT WRT TEMPERATURES
WITH NO CHANGE IN AIRMASS. HIGHS AGAIN IN THE LOWER 80S. LOWS
TONIGHT A TAD WARMER GIVEN ENCROACHING UPPER LEVEL CLOUD COVER
ASSOCIATED WITH THE LOW FORMING OFF THE SE COAST. LOWS IN THE UPPER
50S TO NEAR 60.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...

EXPECTATIONS ARE THAT THE LOW FORMING OFF THE SOUTHEAST COAST WILL
JOG SLOWLY NORTH-NORTHWESTWARD ON THURSDAY GIVEN WEAK STEERING FLOW
ON THE SOUTHERN AND EASTERN PERIPHERY OF CONTINUED RIDGING ALOFT
THAT EXTENDS FROM THE NORTHWEST GOM NEWD INTO THE NORTHEAST US.
THUS...WITH SYSTEM STILL REMAINING OFFSHORE...ANY IMPACTS THURSDAY-
THURSDAY NIGHT ARE STILL EXPECTED TO BE MINIMAL AND MOSTLY CONFINED
TO EASTERN/SOUTHEASTERN PORTIONS OF THE FORECAST AS BERMUDA RIDGING
CONTINUES TO RIDGE WESTWARD INTO THE AREA.

HAVE KEPT SLIGHT TO SMALL CHANCE POPS ACROSS THE SOUTHERN COASTAL
PLAIN AND SANDHILL COUNTIES. ASSOCIATED THICKENING CLOUDS SHIELD
WILL TEMPER DAYTIME HEATING IN THESE AREAS AS WELL...WITH HIGHS
RANGING FROM MID TO UPPER 70S ACROSS THE SOUTHEAST TO LOWER 80S OVER
THE WESTERN-CENTRAL PIEDMONT. BROKEN/OVERCAST SKIES COUPLED WITH
MORE HUMID AIR BEING DRAWN INTO THE AREA BY THE STRENGTHENING
ONSHORE FLOW WILL RESULT IN MILDER OVERNIGHT LOWS IN THE UPPER 50S
TO LOWER 60S.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 230 AM WEDNESDAY...

THE MAIN FORECAST CHALLENGE LATE WEEK INTO THE WEEKEND REMAINS THE
EVOLUTION OF AN AREA OF LOW PRESSURE... WITH POSSIBLE SUB-TROPICAL
CHARACTERISTICS... FORECAST TO FORM NEAR THE BAHAMAS AND DRIFT NEAR
THE SOUTHEAST US COAST. THE TRACK OF THE POTENTIALLY SUBTROPICAL LOW
OFF/NEAR THE COAST HAS BEEN TRENDING WESTWARD WITH TIME... WITH MOST
MODELS CURRENTLY IN GENERAL AGREEMENT WITH THE LOW PRESSURE
POTENTIALLY REACHING NEAR THE NORTHERN SC COAST FRIDAY INTO
SATURDAY... THEN MEANDERING AROUND THE NC/SC BORDER REGION INTO THE
WEEKEND BEFORE WASHING OUT. HOWEVER... THE LOW HAS YET TO DEVELOP
AND IT WILL LIKELY BE A FEW MODEL RUNS BEFORE THE FORECAST
CONFIDENCE OF THE SYSTEM`S EVOLUTION BECOMES HIGH.

NOT SURPRISINGLY... THE QPF OF THE MODELS ARE ALL OVER THE PLACE NOT
ONLY WITH AMOUNTS (A FEW TENTHS OF AN INCH TO SEVERAL INCHES)... BUT
WITH PLACEMENT (RANGING FROM SC OR SOUTHERN NC TO OFFSHORE IN THE
GULF STREAM).

THEREFORE... WE WILL MAINTAIN OUR CURRENT FORECAST WHICH HIGHLIGHTS
MORE CLOUDS AND COOLER DAYTIME TEMPERATURES IN THE SOUTH AND EAST...
WITH HIGHER POPS IN THE SOUTH AND EAST FRI-SUN.

AFTER THAT... EARLY NEXT WEEK... A COLD FRONT SHOULD INCREASE THE
SHOWER AND THUNDERSTORM CHANCES FOR THE WEST AND NORTH BY MONDAY
NIGHT AND/OR TUESDAY... BEFORE DRYING AND COOLING CONDITIONS ARRIVE
MIDWEEK.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 135 PM WEDNESDAY...

24-HOUR TAF PERIOD: HIGH CONFIDENCE THAT VFR CONDITIONS...WITH JUST
SOME SCATTERED TO BROKEN HIGH CLOUDS...WILL PREVAIL THROUGH THE TAF
PERIOD AS HIGH PRESSURE CONTINUES RIDGING INTO THE AREA FROM THE
EAST. THERE IS A SLIGHT CHANCE FOR SOME SUB-VFR CIGS MOVING INTO THE
FAR SOUTH (KFAY) THURSDAY AFTERNOON...BUT WILL LEAVE MENTION OUT FOR
NOW. EASTERLY WINDS THIS AFTERNOON WILL BECOME LIGHT OVERNIGHT...
INCREASING AGAIN ON THURSDAY...STRONGEST IN THE SOUTH AND EAST.
EXPECT BROKEN CIGS AT 25 KFT (LOWER AT KFAY) BY 18Z THURSDAY. RAIN
SHOULD NOT IMPACT THE TERMINAL UNTIL AFTER THE 24 HOUR TAF PERIOD...
BUT SHOULD THEY MOVE IN EARLIER...KFAY AND KRWI WOULD BE THE FIRST
SITES TO EXPERIENCE THEM.

LOOKING AHEAD: THE MAIN AVIATION CONCERN FOR THURSDAY NIGHT THROUGH
MONDAY CONTINUES TO BE THE COASTAL LOW...CURRENTLY OFF THE FLORIDA
COAST...WHICH WILL SLOWLY DRIFT NORTHWARD ALONG THE SOUTHEAST U.S.
COAST...STALLING AND MEANDERING SOMEWHERE IN THE VICINITY OF SOUTH
CAROLINA OR NORTH CAROLINA LATE IN THE WEEK AND THROUGH THE WEEKEND.
ALTHOUGH MODEL AGREEMENT CONTINUES TO GET BETTER WITH THIS SYSTEM...
THERE IS STILL A LOT OF UNCERTAINTY WITH RESPECT TO THE PATH OF THIS
SYSTEM...BUT REGARDLESS...THIS SYSTEM COULD RESULT IN SOME ADVERSE
AVIATION IMPACTS IN WIDESPREAD SHOWERS AND THUNDERSTORMS...AND COULD
PERSIST THROUGH SUNDAY...ESPECIALLY ACROSS SOUTHERN AND EASTERN NC.
ADDITIONALLY...ENHANCED EASTERLY ONSHORE FLOW FROM THIS SYSTEM COULD
BRING AN INCREASE THREAT FOR MORNING STRATUS/FOG.

&&

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

&&

$$
SYNOPSIS...RAH
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...BADGETT
AVIATION...RAH


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