Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | 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 030205
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1005 PM EDT WED SEP 2 2015

.SYNOPSIS...A DISTURBANCE WILL DIVE FROM CENTRAL VA TO EASTERN NC
THROUGH EARLY THU. A LEE TROUGH WILL OTHERWISE LINGER OVER CENTRAL
NC UNTIL A BACK DOOR COLD FRONT MOVES SOUTHWEST ACROSS THE AREA LATE
FRI AND FRI NIGHT.

&&

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

WATER VAPOR SATELLITE IMAGERY DEPICTS A WELL-DEFINED SHORTWAVE
TROUGH OVER CENTRAL VA THIS EVENING. THIS FEATURE EARLIER FORCED
SCATTERED TO NUMEROUS SHOWERS AND STORMS OVER VA...WHICH HAVE
SUBSEQUENTLY PROPAGATED GENERALLY SOUTHEASTWARD INTO THE NORTHERN NC
PIEDMONT AND COASTAL PLAIN. THE ASSOCIATED OUTFLOW BOUNDARY
STRETCHED AT 0145Z FROM NEAR KBUY TO KRDU TO KASJ. WHILE SHOWERS
HAVE PERCOLATED ALONG THE LENGTH OF THE BOUNDARY...THE ORIENTATION
OF SHEAR VECTORS (FROM THE NW) RELATIVE TO THE BOUNDARY HAVE FOCUSED
STRONG AND SUSTAINED CONVECTIVE MAINTENANCE ALONG THE SE-FACING
OUTFLOW FLANK...AND THIS PROCESS WILL CONTINUE AND FAVOR FAR EASTERN
HALIFAX AND EDGECOMBE COUNTIES FOR THE STRONGEST CONVECTION DURING
THE NEXT HOUR.

OTHERWISE...SCATTERED OR WIDELY SO SHOWERS AND ISOLATED THUNDER WILL
OCCASIONALLY PERCOLATE...ALONG OUTFLOW...SOUTHEASTWARD WITH THE
PASSAGE OF THE AFOREMENTIONED SHORTWAVE TROUGH AND ASSOCIATED
FORCING FOR ASCENT AS IT CONTINUES SOUTHEASTWARD TOWARD THE PAMLICO
SOUND BY 12Z - TIMING WHICH SHOULD RESULT IN RAIN CHANCES MOVING
SOUTHEAST OF THE RAH CWFA BY AROUND 09Z. PERSISTENCE LOWS IN THE
UPPER 60S TO LOWER 70S.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 333 PM WEDNESDAY...

THE MID LEVEL VORTICITY MAX SHOULD BE SHIFTING OFF THE NRN NC COAST
THU MORNING... ALBEIT WITH A WEAK TRAILING SHEAR AXIS EXTENDING BACK
ACROSS THE NRN CWA. THIS TRAILING VORTICITY WILL SINK SLOWLY
SOUTHWARD THROUGH THE DAY BUT REMAIN EXTENDED ACROSS THE SRN CWA
LATE THU THROUGH THU NIGHT. PW VALUES WILL HAVE FALLEN WITH A
SLIGHTLY MORE STABLE AND SUBSIDING COLUMN BEHIND THE CORE OF THE
EXITING WAVE... SO EXPECT ANY SHOWER/STORM COVERAGE TO BE FAIRLY
SMALL GIVEN THE WEAK WIND FIELD... LACK OF STRONG FORCING FOR
ASCENT... AND LIMITED CAPE. WILL RETAIN AN ISOLATED POP JUST ACROSS
THE SOUTH AND SE NEAR THE SHEAR AXIS AND WHERE LOW LEVEL DEWPOINTS
WILL LIKELY BE HIGHER. ANOTHER MUCH WEAKER WAVE WILL PUSH INTO THE
REGION FROM THE SW LATE THU INTO THU NIGHT... BUT THIS APPEAR TO
CONTRIBUTE VERY LITTLE DYNAMIC FORCING... AND WITH LACK OF HEATING
AFTER SUNSET... COVERAGE SHOULD BE ISOLATED AT BEST WITH THIS SECOND
WAVE. WILL KEEP A MENTION OF ISOLATED STORMS IN THE NE CWA THROUGH
THE EVENING... THEN TREND POPS DOWN BELOW 15% OVERNIGHT. THIS
PATTERN CORRELATES WITH THE LOCATION OF THE SREF`S HIGHER CHANCES OF
MEASURABLE PRECIP. WITH GOOD MIXING AND CONTINUED ABOVE NORMAL
THICKNESSES... EXPECT STEAMY HIGHS OF 90-95. LOWS 67-72 UNDER PARTLY
CLOUDY SKIES. -GIH

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 315 PM WEDNESDAY...

THE MAIN PLAYER IN THE WEATHER PATTERN FOR THE LONG TERM WILL BE A
1026 MB SURFACE HIGH PRESSURE SYSTEM OVER NEW ENGLAND THAT WILL PUSH
A BACKDOOR COLD FRONT THROUGH THE AREA ON FRIDAY NIGHT AND SET UP A
WEDGE FRONT THAT IN PATTERN WILL BE REMINISCENT OF A COLD AIR
DAMMING SCENARIO BUT WITHOUT THE ISENTROPIC LIFT THAT WE USUALLY SEE
CONTRIBUTING TO MORE STRATIFORM RAIN ACROSS THE TRIAD. THE FEATURE
THROUGH WILL CAUSE LOW CLOUDS TO SPREAD ACROSS MUCH OF THE AREA ON
SATURDAY AND BRING IN MUCH COOLER HIGH TEMPERATURES (LOW TO MID 80S).

AS THE WEEKEND CONTINUES...A VERY WEAK LOW OFF OF THE FLORIDA COAST
WILL ATTEMPT TO HELP FORM AN INVERTED TROUGH ALONG THE CAROLINA
COAST BUT THE STRENGTH OF THIS FEATURE REMAINS UNCERTAIN AT THIS
TIME. CURRENT MODEL RUNS SUGGEST THAT THIS FEATURE MAY REMAIN FAIRLY
WEAK BUT IT WILL CERTAINLY CAUSE AN UPTICK IN POPS ACROSS EASTERN
PORTIONS OF THE CWA...PARTICULARLY SUNDAY AND MONDAY AFTERNOONS
DURING PEAK HEATING WITH PSEUDO WEDGE FRONT BOUNDARY HELPING TO
INITIATE CONVECTION. THE EXACT LOCATION OF THIS BOUNDARY IS TO BE
DETERMINED AND THUS THE AFTERNOON FORECAST REMAINS FAIRLY LOW
CONFIDENCE BUT GENERAL TRENDS SUGGEST THAT RAIN WILL BE MORE LIKELY
FURTHER EAST.

ON TUESDAY THE SURFACE HIGH BREAKS DOWN AND TEMPERATURES WILL START
A SLOW WARMING TREND INTO THE MID TO UPPER 80S BY MID WEEK. THE MAIN
THREAT FOR PRECIPITATION WILL BE WITH A FEW SHORTWAVES ALONG THE
SOUTH CAROLINA COAST WHICH MAY PROVIDE SOME FORCING FOR DIURNAL
SHOWERS OR STORMS BOTH DAYS.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 145 PM WEDNESDAY...

HIGH CONFIDENCE IN VFR CONDITIONS HOLDING THROUGH MID AFTERNOON
THU... ALTHOUGH THERE WILL BE ONE BRIEF PERIOD OF EXCEPTION. THE
PASSAGE OF AN UPPER LEVEL DISTURBANCE FROM NW TO SE THROUGH THE
REGION LATE TODAY THROUGH THIS EVENING WILL BRING SCATTERED
STORMS... MOST LIKELY TO AFFECT RWI AND PERHAPS RDU... WITH INT/GSO
SEEING A SLIGHTLY LOWER CHANCE OF STORMS AND FAY SEEING THE LEAST
CHANCE. THE PRIMARY WINDOW OF STORM POTENTIAL WILL BE 21Z-01Z AT
INT/GSO/RDU/RWI. A SHORT PERIOD OF GUSTY WINDS AND MVFR TO IFR
CONDITIONS CAN BE EXPECTED IN AND NEAR ANY STORMS... ALTHOUGH
COVERAGE WILL BE SMALL AND DURATION LESS THAN AN HOUR AT ANY GIVEN
LOCATION. OTHERWISE... ANY CIGS ARE LIKELY TO BE ABOVE 6K FT AGL.
LIGHT AND VARIABLE SURFACE WINDS WILL BECOME PREDOMINANTLY FROM THE
NE OR NORTH TONIGHT BUT REMAIN LIGHT THROUGH THU.

LOOKING BEYOND 18Z THU... VFR CONDITIONS LIKELY TO HOLD. THE CHANCE
OF SHOWERS AND STORMS INCREASES LATE FRI INTO FRI NIGHT IN
ASSOCIATION WITH A COLD FRONT PASSAGE... FOLLOWED BY A LOWER CHANCE
SAT AFTERNOON. SUB-VFR LOW CLOUDS AND FOG POSSIBLE LATE FRI NIGHT /
EARLY SAT MORNING... AND AGAIN LATE SAT NIGHT / EARLY SUN MORNING
WITH A LOW LEVEL FLOW FROM THE EAST OR NE BEHIND THE FRONT DRAWING
ATLANTIC MOISTURE INTO THE AREA. -GIH

&&

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

&&

$$

SYNOPSIS...26
NEAR TERM...26
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD



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