Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 060731
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
330 AM EDT MON JUL 6 2015

.SYNOPSIS...A WEAK FRONT NEAR THE VIRGINIA BORDER WILL LIFT NORTH
TODAY AS AN UPPER LOW AND ASSOCIATED WEAK SURFACE LOW OVER WEST
VIRGINIA LIFT OFF TO THE NORTHEAST. BUILDING HIGH PRESSURE OVER THE
SOUTHEAST STATES AND CAROLINAS BEGINNING TONIGHT WILL BRING A TREND
TO WARMER AND DRIER WEATHER THROUGH THE MIDDLE AND END OF THE WORK
WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 320 AM MONDAY...

WATER VAPOR IMAGERY SHOWS A SLOWLY SHEARING UPPER LOW OVER THE OHIO
VALLEY AND AN ASSOCIATED SURFACE LOW OVER WEST VIRGINIA.  A FRONTAL
ZONE EXTENDS SOUTHEAST FROM THE LOW ACROSS SOUTHEASTERN VA AND ALONG
THE NV/VA BORDER THEN DIPS INTO NORTHEAST NC.  ALL CONVECTION HAS
DEPARTED TO THE NORTHEAST AND A RIBBON OF STRATUS IS SLOWLY
DEVELOPING ACROSS THE SOUTHERN AND WESTERN PIEDMONT...PER 11-9.3
MICRON IMAGERY.  IT APPEARS STRATUS WILL MAINLY CONFINED TO AREAS
BETWEEN THE YADKIN/PEE-DEE ROVER AND US HWY 1...AND WILL BURN OFF
BY MID-MORNING.  MEANWHILE...THE AFOREMENTIONED FRONT WILL LIFT NORTH
WELL INTO VA...LEAVING A SURFACE TROUGH OVER THE PIEDMONT.  THE
TROUGH SHOULD BE THE PRIMARY FOCUS FOR SCATTERED CONVECTION UNDER
THE CYCLONIC FLOW ALOFT THIS AFTERNOON...THOUGH DRIER 925MB AND
MIXING APPEAR TO LIMIT FORECAST  INSTABILITY TO ONLY AROUND 1000
J/KG.  BULK SHEAR IS ONLY AROUND 20KT...SO ORGANIZED CONVECTION IS
NOT EXPECTED...THOUGH INCREASING DCAPE COULD STILL ENHANCE WIND
GUSTS FROM A FEW STORMS.  HIGHS IN THE UPPER 80S NORTHWEST TO LOWS
90S SOUTHEAST.

ONE LAST SPOKE OF VORTICITY ROUNDING THE UPPER LOW COULD TRIGGER A
FEW SHOWERS TONIGHT AS IT PASSES ACROSS THE NORTHERN HALF OF THE
AREA....BUT MOST OF THE AREA SHOULD BE VOID OF ANY CONVECTION AS THE
AIRMASS DRIES A BIT AND PW DROPS BELOW 1.5".  LOWS IN THE UPPER 60S
AND LOWER 70S UNDER DECREASING CLOUD COVER.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 330 AM MONDAY...

AFTERNOON SHOWERS AND STORMS SHOULD BE MAINLY ISOLATED TUESDAY AS
THE UPPER LOW SHEARS TO OUR NORTH AND JUST A WEAK PIEDMONT TROUGH
REMAINS AMIDST RELATIVELY WEAK INSTABILITY.  MODELS DO SHOW A VERY
SHALLOW UPPER SHEAR LEVEL SHEAR AXIS...ABOVE 500 MB...DRIFTING
OVERHEAD...BUT INSTABILITY LOOKS TO BE LOW FOR THIS FEATURE TO
TRIGGER MUCH CONVECTION.  THUS...WILL MAINTAIN JUST SLIGHT CHANCE
POPS...WITH HIGHS COUPLE DEGREES WARMER THAN TODAY IN THE LOWER
90S.  LOWS TUESDAY NIGHT IN THE 69-73 RANGE.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 310 AM MONDAY...

WED-FRI: WITH THE DEPARTURE OF TODAY`S SHORTWAVE TROUGH AND
ASSOCIATED WEAK SURFACE LOW WELL TO OUR NE BY WED MORNING... MID
LEVEL RIDGING WILL BUILD OVER THE SOUTHEAST STATES MID-LATE WEEK.
THE ECMWF/GFS/CANADIAN AND GEFS MEAN ALL DEPICT THIS EXPANSIVE
FEATURE STRETCHING FROM TX/OK TO OFF THE SE COAST... AND THEY AGREE
ON A SLOW RETROGRESSION OF THE RIDGE TOWARD THE SRN PLAINS WITH
TIME. HOWEVER... THEY DIFFER A BIT REGARDING THE STRENGTH AND
CENTERPOINT OF THIS RIDGE... WITH THE CANADIAN CENTERED OVER THE FAR
SRN APPALACHIANS BY FRI... A POSITION BETWEEN THE MORE EASTERLY GFS
AND MORE WESTERLY ECMWF. BUT REGARDLESS OF THE SPECIFICS... THIS
RIDGE WILL SERVE TO SUPPRESS THE WESTERLIES WELL TO OUR NORTH AND
WILL STEADILY PUSH UP LOW LEVEL THICKNESSES ACROSS THE CAROLINAS...
FROM AROUND 5 M ABOVE NORMAL WED TO AS MUCH AS 10-15 M ABOVE NORMAL
FRI. GIVEN THAT WE`RE APPROACHING THE CLIMATOLOGICALLY HOTTEST TIME
OF THE YEAR... IT WON`T TAKE MUCH TO PUSH UP TEMP/HUMIDITY TO
UNCOMFORTABLE LEVELS. STATISTICAL GUIDANCE SUPPORTS HIGHS MOSTLY IN
THE LOWER 90S WED WARMING TO THE MID TO PERHAPS UPPER 90S BY FRI...
WITH LOWS FROM AROUND 70 TO MID 70S... A SLIGHT UPWARD BUMP FROM
PREVIOUS FORECASTS. DESPITE THE WARM SURFACE TEMPS... DEEP
SUBSIDENCE ALOFT AND LOW SHEAR ALONG WITH PW VALUES NEAR TO JUST
SLIGHTLY ABOVE NORMAL WILL LIMIT CONVECTION COVERAGE. EXPECT
SHOWER/STORM CHANCES WED-FRI TO BE JUST UNDER CLIMATOLOGY (15-30%)
AND LARGELY CONFINED TO OUR SOUTHEAST... ALONG THE INLAND-MOVING SEA
BREEZE... AND ACROSS THE FAR NORTH... NEAR THE DECAYING SURFACE
FRONTAL ZONE STRETCHED ACROSS VA.

SAT-SUN: THE MID LEVEL RIDGE CENTER IS EXPECTED TO HAVE SHIFTED
WESTWARD TO TX/OK BY THE WEEKEND... AND THE RESULTING NW FLOW OVER
NC WILL ALLOW SHORTWAVE ENERGY TO DROP ESE ACROSS NRN AND ERN NC.
ONE PRONOUNCED WAVE IN PARTICULAR SKIRTS ACROSS VA AND FAR NE NC
LATE SAT INTO SAT NIGHT ACCORDING TO THE GFS/ECMWF. AND WITH THE
RIDGE CENTER LIKELY TO CONTINUE A WESTWARD DRIFT TO NM/FOUR CORNERS
REGION BY SUN... ADDITIONAL DISTURBANCES APPEAR LIKELY TO CROSS
VA/NC SUN AS WELL. CLOUDS AND BETTER PRECIP COVERAGE MAY TRIM A
COUPLE DEGREES OFF HIGHS OVER THE WEEKEND ACROSS OUR NORTH AND
EAST... BUT IT SHOULD STILL REMAIN WARM AND HUMID WITH SLIGHTLY
ABOVE-NORMAL THICKNESSES YIELDING HIGHS OF 90-95... HOTTEST IN THE
SW CWA. WITH THE UPTICK IN DYNAMIC FORCING AND SLIGHTLY BETTER DEEP
LAYER SHEAR... WILL NUDGE UP POPS TO 20-40%... MAINLY ACROSS THE
NORTH/EAST. -GIH

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 140 AM MONDAY...

THE BULK OF LAST EVENINGS SHOWERS AND STORMS HAVE MOVED OFF INTO SE
VA...BUT AN ISOLATED SHOWER IS STILL POSSIBLE OVERNIGHT WITH A
LINGER FRONT JUST NORTH OF KRDU AND KRWI.  MEANWHILE...SOME CLEARING
ACROSS THE WESTERN PIEDMONT MAY RESULT IN PATCHY FOG AND/OR AN AREA
OF STRATUS...FOCUSED MOSTLY BETWEEN KGSO AND KRDU BASED ON NEAR TERM
MODEL GUIDANCE....THOUGH KINT/KGSO/KRDU/KRWI COULD ALL SEE SOME IFR
CEILINGS BY 12Z.

LATER TODAY...AFTER ANY MORNING STRATUS BURNS OFF...SCATTERED STORMS
ARE EXPECTED TO DEVELOP...PRIMARILY FROM KRDU TO THE EAST...MOVING
OFF TO THE NORTHEAST DURING THE LATE AFTERNOON AND EVENING.

LONG TERM: CONVECTIVE COVERAGE SHOULD BEGIN TO DECREASE IN THE
COMING DAYS AS HIGH PRESSURE BEGINS TO INFLUENCE THE PATTERN A
LITTLE MORE. STILL LIKELY THAT WE WILL SEE DIURNAL SHOWERS AND
STORMS THROUGH THE END OF THE WEEK.

&&

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

&&

$$

SYNOPSIS...HARTFIELD/22
NEAR TERM...22
SHORT TERM...22
LONG TERM...HARTFIELD
AVIATION..ELLIS/22


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