Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 070727
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
325 AM EDT TUE JUL 7 2015

.SYNOPSIS... AN UPPER TROUGH ACROSS THE SOUTHERN APPALACHIANS WILL
LIFT AWAY FROM THE REGION TODAY. A RIDGE OF HIGH PRESSURE WILL THEN
DEVELOP OVER THE SOUTHEAST AND STRENGTHEN THROUGH THE REMAINDER OF
THE WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 915 PM MONDAY...

ISOLATED/SCATTERED CONVECTION THAT DEVELOPED EARLIER THIS AFTERNOON
HAS SHOWN A SLOW DOWNWARD TREND SINCE 00Z. THE EXCEPTION IS A BROKEN
NARROW BAND OF SHOWERS WITH ISOLATED T-STORMS WHICH EXTEND FROM EAST
OF THOMASVILLE TO NEAR ROXBORO. THIS BAND OF CONVECTION OCCURRING
ALONG A WEAK 850-700MB TROUGH WITH SOME ADDITIONAL SUPPORT ALOFT
FROM A VORT AXIS LIFTING N-NE ACROSS WESTERN NC. DUE TO THE PRESENCE
OF THIS FEATURE INTERACTING WITH THE MOISTURE AVAILABLE AND LOW
LEVEL (THOUGH WEAK) INSTABILITY...SHOULD SEE ISOLATED-SCATTERED
CONVECTION PERSIST WEST OF HIGHWAY THROUGH THE EVENING HOURS WITH A
DECREASE IN COVERAGE DURING THE OVERNIGHT HOURS.

LATER TONIGHT...EXPECT TO SEE AREAS OF STRATUS ONCE AGAIN DEVELOP
THOUGH EXPECT IT TO BE RELATIVELY THIN AND BRIEF IN DURATION. MIN
TEMPS 68-73.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 335 PM MONDAY...

EXPECT A PERIOD OF EARLY MORNING STRATUS TO START THE DAY WITH
CLOUDS LIFTING AND INTERVALS OF SUNSHINE ARRIVING TOWARD MID TO LATE
MORNING. CONVECTIVE COVERAGE ON TUESDAY SHOULD AGAIN BE LIMITED AS
THE UPPER TROUGH LIFTS NORTH SOMEWHAT AND THE AIR MASS DRIES OUT
WITH PW VALUES DROPPING 0.25 TO 0.50 INCHES FROM MONDAY AFTERNOON TO
TUESDAY AFTERNOON. A WEAK SURFACE TROUGH ORIENTED SOUTHWEST ACROSS
THE PIEDMONT COULD HELP TO INITIATE WIDELY SCATTED CONVECTION.
GIVEN WEAK FLOW AND GENERALLY WEAK INSTABILITY...SEVERE WEATHER
THREAT APPEARS MINIMAL. WILL INCLUDE SLIGHT CHANCE POPS MAINLY
ACROSS THE EAST FOR TUESDAY AFTERNOON AND EVENING. THICKNESS VALUES
INCREASE A BIT AS HEIGHTS RISE SLIGHTLY. THIS WILL SUPPORT HIGHS IN
THE 89 TO 94 RANGE. -BLAES

&&



.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 325 AM TUESDAY...

THU: THE WEAK PIEDMONT SURFACE TROUGH WILL HOLD OVER CENTRAL NC...
WHILE THE SYNOPTIC FRONTAL ZONE SETTLES SOUTHWARD INTO VA. EXPANSIVE
MID LEVEL RIDGING FROM THE LOWER MISS VALLEY ACROSS THE SOUTHEAST
STATES CONTINUES TO SLOWLY RETROGRADE WHILE SUPPRESSING THE
WESTERLIES TO OUR NORTH. ABUNDANT HEATING IS ASSURED.... WHICH WILL
PUSH THICKNESSES UP TO 5-10 M ABOVE NORMAL... INDICATING HIGHS IN
THE LOWER-MID 90S. FALLING DEWPOINTS WITH MIXING BY AFTERNOON SHOULD
KEEP HEAT INDICES BELOW CRITICAL VALUES OVER MUCH OF THE CWA
(ALTHOUGH THEY MAY EXCEED 100F BRIEFLY IN THE SE CWA). GIVEN THE
DEEP LAYER SUBSIDENCE AND NEAR-NORMAL PW... ANY SUBSTANTIAL RAIN
CHANCES WILL BE VERY LOW AND CONFINED TO THE EXTREME NORTH...
POTENTIALLY ALONG OUTFLOW EMANATING FROM CONVECTION ALONG THE FRONT
(PERHAPS ENHANCED BY A LOW CROSSING MD/DE)... AND ALONG AN INLAND-
MOVING SEA BREEZE LATE IN THE DAY.

FRI: THE SYNOPTIC FRONT TO THE NORTH APPEARS LIKELY TO DIP NEAR OR
JUST INTO NE NC... WITH A RESIDUAL OUTFLOW POTENTIALLY DROPPING
FURTHER SOUTH WELL INTO NORTH CENTRAL NC... WHILE ALOFT... THE MID
LEVEL ANTICYCLONE CENTER CONTINUES TO DRIFT WESTWARD OVER THE LOWER
MISS VALLEY. WITH THE SUBSEQUENT TILT/DIP IN THE WESTERLIES DOWN THE
MIDATLANTIC COAST... MODELS DO TREND TOWARD A BIT MORE WEAK
SHORTWAVE ENERGY TRACKING SOUTHEASTWARD BRUSHING NE NC FRI NIGHT...
ALTHOUGH THE PROJECTED INSTABILITY SHOULD BE LOW (MUCAPE UNDER 750
J/KG ON THE GFS)... AND PW WILL ONLY BE SLIGHTLY ELEVATED OVER THE
ERN CWA. WILL PLACE LOW CHANCE POPS ACROSS THE NORTH/NE CWA AND IN
THE COASTAL PLAIN... ALONG THE WEAK SURFACE TROUGH. THICKNESSES WILL
AGAIN BE 5-10 M ABOVE NORMAL... SO EXPECT HIGHS ONCE AGAIN IN THE
LOW-MID 80S. LOWS 70-74 WITH LINGERING ISOLATED POPS OVER THE FAR
NORTH AND NORTHEAST OVERNIGHT.

SAT-MON: THE COMBINATION OF THE BUILDING RIDGE OVER THE SRN PLAINS
AND UP THE FRONT RANGE OF THE ROCKIES AND RESULTING STRENGTHENING NW
FLOW FROM THE UPPER MIDWEST THROUGH THE LOWER GREAT LAKES TO THE
MIDATLANTIC COAST WILL PLACE NC IN A MORE ACTIVE AND VOLATILE
WEATHER PATTERN... HIGHLIGHTED BY POCKETS OF MID LEVEL SHORTWAVE
ENERGY CROSSING OUR REGION IN NW STEERING FLOW... TRACKING ALONG THE
OLD DIFFUSE SURFACE FRONTAL ZONE. NORTHERN AND EASTERN PORTIONS OF
THE FORECAST AREA SHOULD SEE THE BEST CHANCES FOR CONVECTION...
ORIGINATING IN A HIGHLY UNSTABLE ENVIRONMENT OVER THE MIDWEST AND
THE OH VALLEY MOVING SOUTHEASTWARD OVER VA/NC. WHILE WE CAN`T
ACCURATELY TRACK SPECIFIC FEATURES AT THIS RANGE... THE IMPROVING
SHEAR AND INSTABILITY ALONG WITH GREATER DYNAMIC FORCING FOR ASCENT
SUPPORT BOOSTING POPS TO SLIGHTLY ABOVE CLIMATOLOGY DURING THIS
PERIOD... AND NOT NECESSARILY PEAKING IN THE TYPICAL LATE-DAY TIME
FRAME EITHER... AS HIGH LAPSE RATES WITHIN AN UPSTREAM EML MAY
SUSTAIN NOCTURNAL CONVECTION AS IT MOVES SOUTHEAST. STILL EXPECT
ABOVE NORMAL THICKNESSES TO EQUATE TO WARM TEMPS TOPPING OUT DAILY
IN THE LOWER TO MID 90S... AND THE THREAT OF 100+F HEAT INDEX VALUES
PARTICULARLY FROM THE TRIANGLE TO THE SOUTH AND EAST WILL LINGER
INTO EARLY NEXT WEEK. -GIH

&&

.AVIATION /00Z TUESDAY THROUGH FRIDAY/...
AS OF 140 AM TUESDAY...

VFR CONDITIONS FOR MOST OF THE REMAINDER OF THE NIGHT...ALTHOUGH A
LITTLE STRONGER FLOW JUST ABOVE THE SURFACE OVER THE COASTAL PLAIN
MAY LEAD TO SOME STRATUS BY 10-12Z.  HOWEVER...MODEL GUIDANCE ISN`T
REALLY INDICATING MUCH MORE THAN JUST A  FEW PATCHES OF IFR
STRATUS...SO THE LATEST TAF WILL REFLECT LESS IN THE WAY OF
RESTRICTIONS.  WHATEVER LOW CLOUDS THAT DO FORM WILL BURN OFF BY
14Z...AND SCATTERED CU IN THE 3-4K FT RANGE WILL DEVELOP FOR THE
AFTERNOON HOURS.  WITH DRIER AIR ON CENTRAL NC...ONLY WIDELY
SCATTERED SHOWERS AND ISOLATED STORMS ARE EXPECTED OVER THE COASTAL
PLAIN...PRIMARILY IN THE VICINITY OF KFAY AND/OR KRWI AFTER 18Z.

OUTLOOK...MOSTLY VFR CONDITIONS THROUGH THE END OF THE WEEK AS HIGH
PRESSURE DOMINATES THE REGION.  SOME AFTERNOON STORMS ARE POSSIBLE
EACH DAY...ALONG WITH EARLY MORNING VSBY RESTRICTIONS.

&&

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

&&

$$

SYNOPSIS...BLAES
NEAR TERM...WSS
SHORT TERM...BLAES
LONG TERM...HARTFIELD
AVIATION...22



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