Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 050221
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1021 PM EDT SAT JUL 4 2015

.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT WILL MOVE OVERHEAD AND INTERACT WITH
A SURFACE FRONT THAT WILL WAVER ACROSS VA AND NC THROUGH MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM SATURDAY...

CONVECTION HAS BEEN ISOLATED TO WIDELY SCATTERED THIS EVENING.
MODEST INSTABILITY (500-1000 J/KG) IS STILL DEPICTED ON THE SPC
MESOSCALE ANALYSIS BUT CIN IS ON THE INCREASE. CONVECTION ACROSS THE
NORTHERN TIER OF THE FORECAST AREA MAY PERSIST A BIT LONGER AS AN
UPPER LEVEL SHEAR AXIS HELPS TO FOCUS THE PRECIP. IN ADDITION...A
SURFACE BOUNDARY IS ALSO LOCATED IN THIS VICINITY. THE SHEAR AXIS IS
PROGGED TO LIFT NORTHWARD THROUGH 06Z...HOWEVER ANOTHER VORT MAX IS
EXPECTED TO TRACK EAST-NORTHEASTWARD FROM SW TN THROUGH 12Z.
HOWEVER...AT THIS TIME IT APPEARS IT WILL REMAIN FAR ENOUGH WEST TO
HAVE TOO MUCH INFLUENCE ON OUR AREA (EXCEPT POSSIBLY OVER THE FAR
NORTHWEST PIEDMONT). NEVERTHELESS...GIVEN THE MOISTURE RICH AIR
MASS...A FEW SHOWERS MAY PERSIST THROUGH THE OVERNIGHT HOURS.
OVERNIGHT LOWS WILL BE SIMILAR TO PREVIOUS NIGHTS...GENERALLY UPPER
60S TO LOWER 70S.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 310 PM SATURDAY...

MID-UPPER LEVEL TROUGH OVER THE TN VALLEY AMPLIFIES...CAUSING
HEIGHTS OVER OUR REGION TO SLOWLY BUILD/EXPAND NORTHWARD. THIS WEAK
SUBSIDENCE MAY INITIALLY INHIBIT CONVECTIVE DEVELOPMENT...ESPECIALLY
ACROSS OUR SE COUNTIES. PERTURBATIONS ALOFT CROSSING WESTERN NC INTO
WESTERN VA WILL AID TO FOCUS LOW LEVEL CONVERGENCE OVER THE NW
PIEDMONT...LEADING TO SCATTERED CONVECTION BY AFTERNOON-EARLY
EVENING. SINCE MAJORITY OF MODEL GUIDANCE HAS BACKED OFF ON UPPER
SUPPORT...HAVE LIMITED POPS TO SOLID CHANCE ACROSS THE NW...TRENDING
TO SMALL CHANCE ACROSS THE SE.

MAX TEMPS SUNDAY AFTERNOON WILL FOLLOW SIMILAR TREND WITH MID 80S NW
DUE TO MIXTURE OF SUN/CLOUDS TO AROUND 90 SE.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 240 PM SUNDAY...

A WEAKENING MID LEVEL LOW INVOF THE SOUTHERN TO CENTRAL APPALACHIANS
MONDAY MORNING IS EXPECTED TO LIFT NORTHWARD AND WEAKEN MONDAY NIGHT
INTO TUESDAY. THE TRAILING ASSOCIATED WEAK S/W TROUGH IS EXPECTED TO
MOVE ACROSS CENTRAL NC ON MONDAY INTO MONDAY NIGHT. THUS... EXPECT
WE COULD SEE SOME SCATTERED SHOWERS AND STORMS MONDAY AFTERNOON INTO
THE EVENING AGAIN... WITH THE HIGHEST PROBABILITY ACROSS THE NORTH
AND EASTERN PORTIONS OF CENTRAL NC.

THE SUB-TROPICAL RIDGE IS THEN FORECAST TO ATTEMPT TO BUILD BACK
OVER THE SOUTHEASTERN U.S. HOWEVER... AS A SERIES OF NORTHERN STREAM
DISTURBANCES TRACK ACROSS THE NORTHERN TIER OF THE COUNTRY THE MID
LEVEL RIDGE WILL HAVE A HARD TIME FULLY EXERTING ITS DOMINATES ON
CENTRAL NC... WITH ANY ASSOCIATED SURFACE FRONT GENERALLY REMAINING
TO THE NORTH OF CENTRAL NC INTO AT LEAST LATE WEEK. HOWEVER... AS
ANY SUBSTANTIAL DISTURBANCES AND ASSOCIATED FRONTS PASS TO THE NORTH
OF CENTRAL NC... EXPECT WE SHOULD STILL SEE A SHARPENING OF THE
PIEDMONT TROUGH OVER CENTRAL NC DURING THIS THE MEDIUM RANGE...
HELPING TO YIELD ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS
EACH AFTERNOON AND EVENING.

HIGH TEMPS DURING THE PERIOD WILL START OFF SLIGHTLY BELOW NORMAL...
GENERALLY IN THE MID TO UPPER 80S ON MONDAY... WITH HIGHS REBOUNDING
TO AROUND NORMAL FOR THE REST OF THE PERIOD (UPPER 80S TO LOWER 90S.
LOW TEMPS ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S... WITH
POSSIBLY A FEW MID 70S BY LATE WEEK INTO NEXT WEEKEND.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 730 PM SATURDAY...

24 HOUR TAF PERIOD: SHOWER IN THE VICINITY OF KRWI WILL MOVE THROUGH
QUICKLY...OTHERWISE TAF SITES STAYING IN THE DRY WEATHER SO FAR.
STILL SOME GUSTS OUT THERE THIS AFTERNOON UP TO 20 KTS OR SO OUT OF
THE SOUTHWEST. THESE ARE EXPECTED TO DIE DOWN AFTER DARK. ISOLATED
TO SCATTERED CONVECTION STILL POSSIBLE THROUGH THE EVENING HOURS BUT
COVERAGE IS LIGHT ENOUGH TO KEEP IT OUT OF THE TAFS AT THIS TIME.
SCATTERED SHOWERS AND THUNDERSTORMS AGAIN POSSIBLE ON SUNDAY
AFTERNOON...INCREASING IN COVERAGE NEAR THE END OF THE TAF PERIOD.
MODELS DO NOT INDICATE MUCH IN THE WAY OF FOG OR LOW STRATUS BUT
TERMINALS RECEIVING RAIN COULD SEE SOME BRIEF DROP IN CONDITIONS
DURING THE OVERNIGHT HOURS.

LONG TERM: LONG TERM MODELS SHOW THE UNSETTLED PATTERN HOLDING OVER
CENTRAL NC...INDICATING A CHANCE FOR SHOWERS AND THUNDERSTORMS AS
WELL AS ADVERSE AVIATION CONDITIONS AT LEAST THROUGH MIDWEEK.

&&

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

&&

$$

SYNOPSIS...26
NEAR TERM...KRD
SHORT TERM...WSS
LONG TERM...BSD
AVIATION..ELLIS


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