Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 061946
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
335 PM EDT MON JUL 6 2015

.SYNOPSIS... AN UPPER TROUGH ACROSS THE SOUTHERN APPALACHIANS WILL
LIFT AWAY FROM THE REGION ON TUESDAY. 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 315 PM MONDAY...

VISIBLE AND WATER VAPOR SATELLITE IMAGERY SHOW MULTIPLE VORTEXES
ACROSS THE SOUTHERN APPALACHIANS. THE LARGER CIRCULATION ASSOCIATED
WITH THE UPPER LEVEL TROUGH AXIS IS EARLY SEEN ON REGIONAL WV
IMAGERY. IT WAS LOCATED ACROSS EASTERN TN AND WESTERN NC AND WAS
TRIGGERING CONVECTION ACROSS WV AND SOUTHWESTERN VA. ANOTHER
VORTEX...THIS ONE LOCATED IN SOUTHERN VA...WAS MORE SHALLOW AND CAN
BE IDENTIFIED IN THE VISIBLE SATELLITE IMAGERY. ONLY ISOLATED
CONVECTION HAS DEVELOPED SO FAR TODAY...MAINLY IN A NORTHEAST-
SOUTHWEST AXIS WHERE ENHANCED CUMULUS CLOUDS ARE INVIGORATED. LATEST
MESOANALYSIS SHOWS A WEAKLY UNSTABLE ENVIRONMENT WITH POOR MID LEVEL
LAPSE RATES HINDERING UPDRAFTS. IN ADDITION...WEAK...
UNIDIRECTIONAL LOW AND MID FLOW SHOULD KEEP STORM UNORGANIZED.
LOCALIZED FORCING FOR ASCENT WILL BE DRIVEN BY SPOKES OF VORTICITY
EMANATING FROM THE UPPER LOW AND IN SOUTHWEST-NORTHEAST CONVERGENCE
ZONES RESULTING FROM DIFFERENTIAL HEATING FROM MORNING STRATUS IN
THE EASTERN PIEDMONT AS WELL THE INLAND PENETRATING SEA BREEZE.
ANOTHER AREA OF CONVERGENCE WILL BE LOCATED ALONG A WEAK SURFACE
TROUGH IN THE WESTERN PIEDMONT. THE CONVECTION WILL HAVE A STORM
MOTION TO THE NORTHEAST WITH THE LARGER CONVECTIVE LINES GRADUALLY
SHIFTING EASTWARD. MOST OF THE CONVECTION THIS EVENING SHOULD
DIMINISH WITH SUNSET BUT GIVEN THE PROXIMITY OF THE THE UPPER
TROUGH...WOULD NOT BE SURPRISED TO SEE A SHOWER OR STORM LINGER INTO
THE OVERNIGHT. BUT A GENERAL DRYING OF THE ATMOSPHERE SHOULD LIMIT
COVERAGE OVERNIGHT AND BRING CONVECTIVE ACTIVITY TO AN END BY MID
EVENING. LOWS WILL RANGE IN THE UPPER 60S TO LOWER 70S. -BLAES
&&

.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 /WEDNESDAY THROUGH MONDAY/...
AS OF 150 PM MONDAY...

GRADUAL WESTWARD REGRESSION OF SUBTROPICAL RIDGING WILL LIFT THE
WESTERLIES AND PERSISTENT FRONTAL ZONE NORTH OF THE AREA IN THE
MIDWEEK. THE FRONTAL ZONE MAKES A SOUTHERLY JOG ON FRIDAY AS THE
RIDGE BEGINS TO AMPLIFY INTO THE CENTRAL CONUS...WITH ENSUING
NORTHWEST FLOW AND A GRADUAL UPTICK IN HEIGHTS OVER THE EAST COAST
THROUGH THE WEEKEND.

THE RIDING WILL LIMIT CONVECTION THROUGH FRIDAY...WITH SLIGHT
CHANCES...PRIMARILY DIURNALLY DRIVEN...ACROSS THE NORTHERN TIER DUE
TO PROXIMITY WITH THE ACTIVE WESTERLIES ZONE ACROSS THE OHIO VALLEY.
HIGHS WILL RANGE FROM 90 ACROSS THE NORTH TO 95 IN THE SOUTH AFTER
MORNING LOWS IN THE LOWER 70S.

OVER THE WEEKEND...DEEP NORTHWEST STEERING FLOW WILL INCREASE THE
CHANCE THAT UPSTREAM MESOSCALE DISTURBANCES WANDER IN TO INITIATE
CONVECTION ACROSS THE AREA. WILL THUS MAINTAIN CHANCE (30-40)
POPS...SHADED TOWARDS MAX HEATING EACH DAY...ON SATURDAY THROUGH
MONDAY. HIGHS WILL BE A COUPLE OF DEGREES WARMER...MOSTLY IN THE MID
90S...WITH POTENTIAL FOR SOME UPPER 90S ACROSS THE SOUTHERN TIER.


&&

.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 240 PM MONDAY...

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON AND PERSIST INTO THE EVENING HOURS. THE CONVECTION IS
EXPECTED TO BE THE MOST WIDESPREAD ACROSS THE COASTAL PLAIN AND
EASTERN PIEDMONT ALTHOUGH CONVECTION IS POSSIBLE ANYWHERE ACROSS
CENTRAL NC. STILL...THE COVERAGE IS LIKELY TO BE A LITTLE MORE
LIMITED THAN PREVIOUS DAYS AND WE WILL OMIT MENTION OF THUNDER IN
THE TAFS AND INCLUDE A TEMPO OF SHRA. ANOTHER ROUND OF STRATUS
APPEARS A GOOD BET OVERNIGHT ALTHOUGH NOT SURPRISINGLY GUIDANCE
DIFFERS ON THE PREFERRED LOCATION AND DEGREE OF COVERAGE. FOR NOW...
WILL INCLUDE A TEMPO PERIOD BEFORE AND JUST A LITTLE AFTER SUNRISE
TO ACCOUNT FOR SOME MVFR CEILINGS. CONDITIONS SHOULD BEGIN TO
IMPROVE AFTER SUNRISE TUESDAY WITH VFR SKY CONDITIONS LIKELY BY 14Z.
A MAINLY LIGHT SOUTHWESTERLY WIND AT AROUND 10KTS OR LESS IS
EXPECTED THROUGH THE PERIOD.

OUTLOOK...A RIDGE WILL BUILD OVER THE SOUTHEAST THROUGH THE PERIOD
SETTING UP A TYPICAL SUMMERTIME PATTERN. VFR CONDITIONS ARE EXPECTED
TO DOMINATE OUTSIDE OF MAINLY ISOLATED AFTERNOON OR EVENING
THUNDERSTORMS AND PATCHY FOG AROUND DAYBREAK. -BLAES

&&

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

&&

$$

SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...MLM
AVIATION..BLAES



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