Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 280711
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
311 AM EDT TUE APR 28 2015

.SYNOPSIS...HIGH PRESSURE WILL EXTEND INTO THE AREA FROM THE
NORTHWEST TODAY AND TONIGHT. MEANWHILE... LOW PRESSURE STRENGTHENING
ALONG THE GULF COAST TODAY WILL TRACK EAST THEN NORTHEAST OVER THE
SOUTHEAST STATES LATE TONIGHT THROUGH WEDNESDAY NIGHT... THEN SLOWLY
PULL OFF THE CAROLINA COAST THURSDAY.

&&

.NEAR TERM /TONIGHT/...
AS OF 1010 PM MONDAY...

A DEEP MID/UPPER LEVEL LOW CENTERED OFF THE NEW ENGLAND COAST THIS
EVENING CONTINUES TO PROVIDE THE AREA WITH CYCLONIC FLOW ALOFT...
WITH EMBEDDED S/W DISTURBANCES MOVING THROUGH THE MID-ATLANTIC INTO
THE CAROLINAS. ONE SUCH POTENT S/W IS EXPECTED TO SINK SOUTHWARD AND
INTO CENTRAL NC DURING THE EARLY MORNING HOURS OF TUESDAY.
HOWEVER... WITH THE COMBINATION OF WEAK LOW LEVEL COLD ADVECTION...
POOR DIURNAL TIMING.... AND LACK OF SIGNIFICANT MOISTURE (PW`S ARE
AROUND 0.4-0.5 INCHES... RESULTING IN PW`S OF AROUND 50% OF NORMAL)
NO PRECIP IS EXPECTED... WITH EVEN VERY LITTLE LOW TO MID CLOUD
COVER. IN FACT MOST OF THE CLOUD COVER OVERNIGHT WILL BE FROM SOME
HIGH CLOUD COVER STREAMING INTO THE AREA FROM CONVECTION NEAR THE
GULF COAST. PLAN TO INCREASE THE CLOUDS IN THE GRIDS ACROSS SOUTHERN
PORTIONS OF THE FA GIVEN THE CIRRUS. STILL THINK OVERNIGHT LOWS
SHOULD RANGE FROM THE UPPER 30S TO AROUND 40 ACROSS THE NORTHERN
RURAL LOCATIONS TO THE LOWER TO MID 40S ELSEWHERE... NEAR
STATISTICAL GUIDANCE.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM MONDAY...

WEDNESDAY AND WEDNESDAY NIGHT: TO BE UPDATED SOON.

THURSDAY AND THURSDAY NIGHT: CERTAINLY A SHIFT IN MODEL GUIDANCE
THIS EVENING AS THE INITIAL COASTAL LOW IS MORE SUPPRESSED TO THE
SOUTHEAST AND THE UPPER LOW MOVING IN FROM THE NORTH IS ABLE TO PUSH
SOUTHWARD UNIMPEDED. THE RESULT FOR THURSDAY IS UNCERTAIN WHEN IT
COMES TO PRECIPITATION BUT CHANCES HAVE CERTAINLY DECREASED IN THE
EAST WHERE IT IS POSSIBLE THAT PLACES MAY SEE VERY LITTLE RAIN ON
THURSDAY IN BETWEEN THE COASTAL AND UPPER LOWS. QPF VALUES HAVE ALSO
DROPPED SIGNIFICANTLY ACROSS THE REST OF THE CWA FROM PRIOR
SIMULATIONS. AS THE UPPER TROUGH DIGS SOUTHWARD THERE WILL BE PLENTY
OF FORCING WITH IT AS BULK SHEAR VALUES CLIMB TO NEAR 60 KTS...BUT
MUCH OF THIS BEING IN THE UPPER BOUNDS NEAR 5-6 KM. THIS IS ABOVE
THE MEAGER INSTABILITY THAT MAY SHOW UP BY THURSDAY NIGHT BUT EVEN
IN THE MID-LEVELS THERE COULD BE AS MUCH AS 30 KTS OF SHEAR TO WORK
WITH. AT THIS POINT NOT CONFIDENT ENOUGH TO INTRODUCE THUNDER INTO
THE FORECAST...WOULD EXPECT MAINLY CONVECTIVE SHOWERS ASSOCIATED
WITH THIS FEATURE AT THIS POINT. WITH THE COASTAL LOW FURTHER TO THE
SOUTHEAST...THERE WILL BE LESS OVERRUNNING PRECIP TO LOCK IN THE IN-
SITU DAMMING AND THUS TEMPERATURES ON THURSDAY COULD END UP BEING
HIGHER THAN EXPECTED. WILL RAISE A COUPLE DEGREES FOR NOW MAINLY
HIGHS IN THE MID 60S WITH LOWS IN THE UPPER 40S ON THURSDAY NIGHT. -
ELLIS

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 310 AM TUESDAY...

DEPENDING ON WHERE THE UPPER LOW ENDS UP AND HOW LONG IT LINGERS
OVER NC WILL DETERMINE IF PRECIPITATION LINGERS INTO FRIDAY.
REGARDLESS...QPF VALUES SHOULD BE LIGHT. EVENTUALLY THE LOW WILL
PUSH OFF TO THE EAST BUT REGARDLESS FRIDAY WILL BE THE START OF A
WARMING TREND THAT WILL START HIGHS ON FRIDAY NEAR 70 DEGREES AN END
UP NEAR 80 DEGREES BY MONDAY AFTERNOON. WITH A SURFACE HIGH FINALLY
MOVING INTO A MORE SUMMER-LIKE POSITION OVER THE WESTERN
ATLANTIC...SOUTHERLY RETURN FLOW OVER CENTRAL NC WILL KEEP
TEMPERATURES WARM AND DRY DESPITE ADVECTING A GRADUALLY MOISTENING
AIRMASS WITH PW VALUES GOING FROM A HALF OF AN INCH ON FRIDAY TO
CLOSER TO AN INCH ON MONDAY. LOWS WILL MODERATE THROUGH THIS PERIOD
FROM THE UPPER 40S TO THE UPPER 50S.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 110 AM TUESDAY...

VFR CONDITIONS ARE LIKELY ACROSS CENTRAL NC THROUGH 06Z TONIGHT.
SPRAWLING HIGH PRESSURE WILL EXTEND INTO THE FORECAST AREA FROM THE
NORTHWEST TODAY INTO TONIGHT...  BRINGING FAIRLY DRY AIR NEAR THE
SURFACE... ENSURING UNRESTRICTED VSBYS. WE WILL SEE SOME HIGH CLOUDS
STREAMING IN FROM THE SW THROUGH THE PERIOD... ESPECIALLY TONIGHT...
AS LOW PRESSURE FORMING OVER THE CENTRAL GULF COAST STARTS TO TRACK
SLOWLY TO THE EAST-NORTHEAST... WHILE UPPER LEVEL LOW PRESSURE
APPROACHES FROM THE WEST. WE`LL ALSO HAVE A FEW MID CLOUDS THIS
MORNING... MAINLY OVER THE NRN/ERN TERMINALS (RDU/RWI/FAY)...
RESULTING FROM AN UPPER DISTURBANCE DROPPING SOUTHWARD ALONG THE
MIDATLANTIC COAST. ANY CIGS WILL BE VFR... ABOVE 10 000 FT AGL.
WINDS WILL BE LIGHT AND MAINLY FROM THE NORTH AND NE.

LOOKING BEYOND 06Z TONIGHT... HIGH CLOUDS WILL THICKEN AND LOWER
LATE TONIGHT AS THE LOW PRESSURE MOVES INTO THE SOUTHEAST STATES...
AND CLOUDS BASED AROUND 4000 FT AGL ARE LIKELY TO MOVE IN FROM THE
SW LATE TONIGHT... HOWEVER CIGS WILL REMAIN VFR THROUGH DAYBREAK
WED. THE COMBINATION OF APPROACHING LOW PRESSURE TROUGH ALOFT FROM
THE WEST AND THE SURFACE LOW CROSSING THE SOUTHEAST STATES WILL LEAD
TO LOWERING CIGS AND INCREASING RAIN CHANCES FROM THE SOUTHWEST
WED... LASTING INTO THU. SUB-VFR CIGS ARE POSSIBLE LATE WED INTO
THU... HOWEVER CONFIDENCE IS NOT HIGH... AS THE WORST AVIATION
CONDITIONS MAY HOLD TO OUR SOUTH DURING THIS PERIOD. AVIATION
INTERESTS SHOULD MONITOR LATER FORECASTS AND CONDITIONS. THE CHANCE
OF IFR CONDITIONS INCREASES LATE THU NIGHT INTO FRI AS UPPER LEVEL
LOW PRESSURE MOVES IN FROM THE NW. THE DEPARTURE OF THE LOW PRESSURE
TO OUR EAST LATE FRI WILL BRING IMPROVING CONDITIONS BACK TO VFR
LATE FRI THROUGH SAT AS HIGH PRESSURE BUILDS IN FROM THE WEST. -GIH


&&

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

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...BSD
SHORT TERM...VINCENT/ELLIS
LONG TERM...ELLIS
AVIATION...HARTFIELD



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