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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 160728
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
320 AM EDT SUN JUN 16 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER OUR REGION TODAY. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST MONDAY AND MOVE ACROSS OUR REGION LATE
TUESDAY INTO EARLY WEDNESDAY MORNING.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 315 AM SUNDAY...

FLATTENING OF THE UPPER RIDGE OVER THE MID ATLANTIC WILL RESULT IN
INCREASING WESTERLY FLOW ALOFT WITH MID AND HIGH CLOUDS SPREADING
ACROSS THE AREA TODAY. WESTERLY FLOW ALOFT AND APPROACHING FRONT
WILL TIGHTEN UP THE LEE TROF AND SOUTHWEST FLOW WILL STRENGTHEN TO
10-15 MPH WITH GUSTS TO PERHAPS 22 MPH THIS AFTERNOON. TEMPS WILL
BENEFIT FROM A MILDER START THIS MORNING AND ONGOING MID-UPPER 80S
FORECAST LOOKS GOOD.

CLOUDINESS...MAINLY MID AND UPPER...WILL BECOME PREVALENT TONIGHT AS
THE APPROACHING FRONT TRANSLATES INTO THE LEE TROF. RAIN CHANCES ARE
SMALL AND WILL BE MAINLY ACROSS THE NORTHERN TIER WHICH WILL BE
SKIRTED BY THE REMNANT OF A WEAKENING VORT MAX INDUCED BY CONVECTION
OVER THE OHIO VALLEY EARLY THIS MORNING. MINS WILL BE MILD AND
SEASONABLE...UPPER 60S.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
AS OF 315 AM SUNDAY...

MONDAY AND MONDAY NIGHT...TRANSITION TO A BROAD LONGWAVE TROF WILL
BE UNDERWAY AND THE LINGERING LOW LEVEL TROFFING ALONG THE ATLANTIC
SEABOARD WILL PROMOTE AN INCREASINGLY MOIST AIRMASS. THICKNESSES ARE
RELATIVELY HIGH AND SIMILAR TO SUNDAY...WITH THE POTENTIAL FOR UPPER
80S. MOSTLY CLOUDY SKIES WILL HAMPER INSOLATION A BIT...MOSTLY MID
80S WEST TO UPPER 80S EAST. CHANCES OF SHOWERS WILL INCREASE MONDAY
AFTERNOON INTO MONDAY NIGHT IN INCREASINGLY DISTURBED FLOW...BUT ITS
DIFFICULT TO PICK OUT A PARTICULAR FEATURE DURING THIS TIME FRAME TO
FOCUS ACTIVITY...WILL CONTINUE CHANCE CATEGORY POPS FAVORING THE
WEST AND NORTH.

TUESDAY AND TUESDAY NIGHT: WITHIN A BROAD TROUGH ALOFT EAST OF THE
ROCKIES...A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE TROUGH...AND
PERHAPS A PRECEDING MCV FROM CONVECTION INITIATED AHEAD OF THIS WAVE
OVER THE CENTRAL PLAINS LATER TODAY AND TONIGHT...WILL MIGRATE
THROUGH THE BASE OF THE TROUGH/ACROSS THE CENTRAL APPALACHIANS AND
MIDDLE ATLANTIC REGION TUE. THESE FEATURES WILL BE FOLLOWED QUICKLY
BY AN ELONGATED BUT STRONGER NORTHERN STREAM WAVE IN NW FLOW FROM
THE UPPER MIDWEST TO THE CENTRAL APPALACHIANS TUE NIGHT.

IN THE LOW LEVELS...A PRE-FRONTAL TROUGH OVER VA/NC TUE WILL BE
OVERTAKEN BY A COLD FRONT ATTENDING THE AFOREMENTIONED NORTHERN
STREAM S/W TROUGH...AND THIS MERGED BOUNDARY WILL SETTLE SOUTHWARD
ACROSS CENTRAL NC TUE NIGHT. WITH A CONDITIONALLY UNSTABLE AND
UNCAPPED ENVIRONMENT PER BUFR SOUNDINGS...AND WITH FORECAST
PRECIPITABLE WATER VALUES APPROACHING TWO INCHES...THE WEAK (~20
METER/12 HR) HEIGHT FALLS ASSOCIATED WITH THE SERIES OF DISTURBANCES
ALOFT AND LOW LEVEL CONVERGENCE ALONG THE PRE-FRONTAL TROUGH/FRONT
WILL SUPPORT THE DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS TUE. THE SLOW SOUTHWARD PASSAGE OF THE SURFACE FRONT WILL END
THE THREAT OF CONVECTION FROM NORTH TO SOUTH TUE EVENING AND
OVERNIGHT...WITH JUST A LINGERING CHANCE OF A FEW SHOWERS ALONG THE
FAR SOUTHERN TIER BY WED MORNING.

WHILE WSW MEAN FLOW ALIGNED PARALLEL TO THE UNDERLYING SURFACE FRONT
SUGGESTS DOWNPOURS/ LOCALIZED FLOODING IN TRAINING STORMS ALONG THE
BOUNDARY MAY PROVIDE THE GREATEST IMPACT...INCREASING MID LEVEL
FLOW/BULK SHEAR TO AROUND 30 KTS MAY ALSO SUPPORT MULTI-CELL STORM
ORGANIZATION WITH PRECIPITATION-LOADED STRONG WET MICROBURST WIND
GUSTS. IN ADDITION...FORECAST MAXIMUM SRH AROUND 100 M2/S2 COULD BE
NEARLY DOUBLED LOCALLY INVOF OUTFLOW/BACKED SURFACE FLOW...WHICH
COULD SUPPORT BRIEF SUPERCELLULAR STRUCTURES...THOUGH SUCH A
SCENARIO WILL BE DEPENDENT ON MESO AND STORM SCALE INFLUENCES WITH
LIMITED PREDICTABILITY BEYOND A FEW HOURS. AS SUCH...WILL INCLUDE
ONLY A GENERIC ONE SENTENCE MENTION OF A STRONG TO SEVERE STORM IN
THE HWO FOR NOW FOR TUE. MOSTLY CLOUDY AND STORMY CONDITIONS WILL
SUPPORT HIGHS FROM THE UPPER 70S NW...TO LOWER TO MIDDLE 80S OVER
THE SOUTH...WITH LOWS MOSTLY IN THE UPPER 60S...TO AROUND 70 DEGREES
SOUTH.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 255 AM SUNDAY...

WEDNESDAY THROUGH SATURDAY: BELOW AVERAGE TEMPERATURES - IN THE
UPPER 70S TO LOWER-MIDDLE 80S - IN WEAK POST-FRONTAL HIGH PRESSURE
AND ASSOCIATED GENERALLY EAST TO ENE LOW LEVEL FLOW...WILL THEN
PREVAIL THROUGH THE END OF THE WEEK. HOWEVER...THE SURFACE FRONT
WILL LIKELY LINGER OVER SC THROUGH THU GIVEN CONTINUED FRONT-
PARALLEL FLOW ALOFT IN THE BASE OF BROAD EASTERN CONUS TROUGH. WILL
ACCORDINGLY MAINTAIN A SLIGHT CHANCE OF A SHOWER OR STORM OVER THE
FAR SOUTHERN SANDHILLS AND COASTAL PLAIN...IN CLOSEST PROXIMITY TO
THIS FRONT AND HIGHER BL MOISTURE...AND ALSO TOWARD THE YADKIN RIVER
WHERE A FEW WEAKENING SHOWERS/STORMS MAY DRIFT AFTER INITIATION AND
PROPAGATION FROM THE EASTERN SLOPES. A WARMER SOUTHEASTERLY...TO
SOUTHERLY RETURN FLOW BY SATURDAY...WILL RESULT IN RISING
TEMPERATURES TO AROUND THE 30-YEAR AVERAGE...AND HUMIDITY
LEVELS...BY THE WEEKEND. A RISK OF A FEW LATE AFTERNOON PULSE
SHOWERS OR STORMS WILL CONSEQUENTLY INCREASE TO NEAR CLIMATOLOGICAL
PROBABILITIES...AROUND 20 PERCENT OR SO...BY SAT.

&&

.AVIATION /06Z SUNDAY THROUGH FRIDAY/...
AS OF 130 AM SUNDAY...

VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD. GRADUALLY
INCREASING MOISTURE AND WARMER TEMPS WILL ALLOW BETTER COVERAGE OF
DIURNAL CLOUDS TODAY...POTENTIALLY BROKEN THIS AFTERNOON AROUND
5KFT. SOUTHWEST WINDS WILL BE INCREASING AHEAD OF AN APPROACHING
FRONT...WITH 10-12KTS SUSTAINED TODAY WITH GUSTS TO 20-22KTS THIS
AFTERNOON.  FRONT SAGGING SOUTH AND THE MID AND UPPER FLOW BECOMES
MORE WESTERLY SUNDAY NIGHT...WILL SEE MID LEVEL CLOUDS ON THE
INCREASE...WITH A SMALL CHANCE OF SHOWERS IN THE GSO/INT VICINITY
AFTER 00Z.

IN THE LONGER RANGE...THE APPROACHING FRONT WILL STALL ACROSS THE
AREA MONDAY NIGHT THROUGH TUESDAY...WITH MVFR/IFR CONDITIONS AND
INCREASING COVERAGE OF SHOWERS/STORMS. VFR CONDITIONS WILL RETURN
BEHIND THE FRONT LATE TUESDAY NIGHT AND DOMINATE THROUGH FRIDAY.

&&

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

&&

$$

SYNOPSIS...RAH
NEAR TERM...MLM
SHORT TERM...MLM/MWS
LONG TERM...MWS
AVIATION...MLM