Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KRAH 300754
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
350 AM EDT SAT APR 30 2016

.SYNOPSIS...
A QUASI-STATIONARY FRONT --WITH COOL AND CLOUDY CONDITIONS TO THE
NORTH...AND MUCH WARMER ONES TO THE SOUTH-- WILL REMAIN OVER
SOUTHERN AND SOUTHWESTERN NC TODAY. THE FRONT AND ASSOCIATED
FOLLOWING WARMER TEMPERATURES WILL RETREAT NORTH ACROSS THE MIDDLE
ATLANTIC STATES LATE TONIGHT AND ESPECIALLY SUNDAY. WARM
SOUTHWESTERLY FLOW WILL THEN RESULT THROUGH MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 905 PM FRIDAY...

QUIET AND DRY BUT WITH INCREASING CLOUDS AND SOME FOG POTENTIAL
OVERNIGHT. LATEST ANALYSIS SHOWS THE FRONT STRETCHED ACROSS CENTRAL
VA AND NE NC... POISED TO PUSH A BIT FURTHER SSW INTO NC AS OFFSHORE
LOW PRESSURE OFF THE SE VA COAST DRAWS COOLER AND MORE STABLE AIR IN
FROM THE NNE... WITH THE STABILIZING ASSISTANCE OF NOCTURNAL
COOLING. EXPECT INCREASING AND THICKENING LOW CLOUDS PARTICULARLY
ACROSS THE NORTH AND EAST CWA... WITH POCKETS OF FOG AND DRIZZLE
POSSIBLE THERE. WHILE THE LOW CLOUDS MAY NOT QUITE MAKE IT INTO THE
SW CWA... WE`LL ALSO SEE INCREASING MID AND HIGH CLOUDS OVER OUR
SOUTH AND WEST RESULTING FROM UPPER LEVEL EVACUATION FROM THE
WEAKENING AL MCS. IN SHORT... SKIES SHOULD TREND TO PARTLY CLOUDY
WEST/SOUTH AND MOSTLY CLOUDY NORTH/EAST OVERNIGHT. TEMPS SHOULD
CONTINUE TO FALL BUT LEVEL OFF FOR THE OVERNIGHT HOURS... YIELDING
LOWS FROM THE MID 50S NW TO LOW-MID 60S SW. -GIH

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...

A PORTION OF THE COMPLEX UPPER LOW OVER THE WESTERN US WILL EJECT
EASTWARD AND RACE ACROSS LOWER GREAT LAKES ON SUNDAY...SHUNTING THE
SHORTWAVE RIDGE OVER THE SOUTHEAST US OFFSHORE. MEANWHILE...THE
FRONTAL ZONE LINGERING OVER CENTRAL NC TODAY WILL RETREAT NORTHWARD
IN TO THE MID-ATLANTIC REGION. ONGOING OVER SHOWERS OVER WESTERN
NC...OWING TO SOUTHEASTERLY LOW-LEVEL FLOW AND WEAK HEIGHT FALLS
ALOFT...WILL LIKELY BLEED INTO THE WESTERN PIEDMONT SUNDAY
MORNING...THOUGH WITHOUT BETTER SUPPORT ALOFT THE COVERAGE OF
SHOWERS AND STORMS IS A LITTLE UNCERTAIN WITH EASTWARD EXTENT SUNDAY
AFTERNOON. NAM/GFS FORECAST SOUNDINGS SHOW MODEST STEEPENING OF MID-
LEVEL LAPSE RATES AND MLCAPE POSSIBLY REACHING 1000-1500 J/KG CAPE
AMIDST PW OF 1.25-1.50".  CAPE GENERALLY APPEARS TO BE HIGHER IN THE
WEST..THOUGH THE DEGREE OF SURFACE HEATING IS UNCERTAIN GIVEN THE
AFOREMENTIONED MORNING PRECIP/CLOUD COVER.  DEEP LAYER SHEAR IS
MODEST...30-35KT ACROSS THE NORTH IN CLOSER TO PROXIMITY TO THE
SHORTWAVE CROSSING THE GREAT LAKES AND STRONGER MID-LEVEL FLOW.  THE
MAIN LIMITATION FOR SEVERE WEATHER APPEARS TO BE A LACK OF A
FOCUS...OUTSIDE IF A RIPPLE IN THE FLOW ALOFT.  THUS..ITS HEARD TO
HAVE MORE THAN CHANCE POPS AT THIS POINT...WITH LOW CONFIDENCE IN
ANY SEVERE STORMS.  HIGHS IN THE MID 70S NW TO AROUND 80 SE.

THE NAM AND GFS INDICATE AT LEAST A CHANCE OF LINGERING SHOWERS INT
HE COASTAL PLAIN SUNDAY NIGHT AS THE DEEP LAYER FLOW VEERS TO MORE
WESTERLY AND DEEP MOISTURE SHIFTS EASTWARD. LOWS 61-68 WEST TO EAST.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 350 AM SATURDAY...

DEEP LAYER FLOW WILL BECOME MORE WEST-SOUTHWESTERLY ON MONDAY AS
DISTURBANCES CONTINUE TO TRACK FROM THE CENTRAL PLAINS TO THROUGH
THE OH VALLEY.  MID-LEVEL DRYING AND STRONGER BL MIXING WILL LIMIT
INSTABILITY ACROSS THE NORTHERN/WESTERN PIEDMONT...FOCUSING
SCATTERED SHOWERS AND STORMS TO SOUTHERN PIEDMONT AN COASTAL PLAIN.
MONDAY AFTERNOON.  HOWEVER...A COLD FRONT WILL APPROACH FROM THE
NORTHWEST LATE MONDAY...OFFERING A BETTER FOCUS FOR CONVECTION
MONDAY NIGHT AND INTO TUESDAY...DEPENDING ON HOW FAR SOUTH THE FRONT
SETTLES. FORECAST CONFIDENCE THEN FALLS FOR THE MID TO LATE WEEK
PERIOD AS RIDGE BUILDS OVER THE WESTERN US AND SHORTWAVES DROPPING
SOUTH OUT OF CANADA RESULT INTO A DEEP TROUGH OVER THE EASTERN US.
THE EVENTUAL AMPLITUDE OF THE TROUGH IS UNCERTAIN...BUT THE EC
ENSEMBLE SUGGESTS 2-3 STD BELOW NORMAL OVER THE DEEP SOUTH AND THE
OPERATIONAL GFS SETTLES AN UPPER LOW OVER THE CAROLINAS BY THE END
OF THE WEEK. THIS PATTERN SUGGESTS PERIODS OF SHOWERS WILL CONTINUE
TO BE POSSIBLE...WITH A SURFACE LOW LIKELY TO DEVELOP OFF THE
SOUTHEAST COAST BY THURSDAY...AND DAILY HIGHS AT LEAST A COUPLE
CATEGORIES BELOW NORMAL...IF NOT MORE.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AS OF 200 AM SATURDAY...

IFR TO MVFR RANGE STRATUS (600-2000 FT) --IN NORTHEASTERLY LOW
LEVEL FLOW ON THE COOL SIDE OF A SURFACE FRONT OVER WEST-CENTRAL
NC-- WILL CONTINUE TO EXPAND SOUTHWESTWARD ACROSS CENTRAL NC THIS
MORNING. THIS FRONTAL ZONE WILL SEPARATE LOW OVERCAST TO THE NORTH
FROM WARM VFR CONDITIONS AND A CHANCE OF THUNDERSTORMS ALONG AND
SOUTH OF THE FRONT. ALL CENTRAL NC TAF SITES ARE EXPECTED TO
REMAIN ON THE COOL/CLOUDY SIDE OF THE BOUNDARY TODAY...WITH MERELY
A GRADUAL RISE OF SUB-VFR CEILINGS INTO THE 1500-2500 FT RANGE
THIS AFTERNOON. HOWEVER...SOME EROSION OF THE LOW CLOUDS FROM THE
EDGES MAY LEAD TO A BRIEF SCATTERING TO VFR --MOST LIKELY AT FAY
AND RWI-- FOR A FEW HOUR PERIOD THIS AFTERNOON AND EVENING. A FEW
SHOWERS MAY ALSO AFFECT TRIAD TAF SITES THIS AFTERNOON.

CEILINGS WILL OTHERWISE LOWER ONCE AGAIN OVERNIGHT...ALONG WITH
THE ARRIVAL OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS AT PIEDMONT
TAF SITES THROUGH EARLY SUNDAY.

OUTLOOK: A SERIES OF WAVES OF LOW PRESSURE WILL TRACK ALONG A
STALLED FRONTAL ZONE ALONG THE SOUTHEAST UNITED STATES
COAST...WITH ASSOCIATED PERIODS OF RAIN AND SUB-VFR CONDITIONS
OVER CENTRAL NC...MON NIGHT THROUGH WED.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...HARTFIELD
SHORT TERM...22
LONG TERM...22
AVIATION...MWS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.