Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 191057
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
657 AM EDT SUN OCT 19 2014

.SYNOPSIS....HIGH PRESSURE WILL BUILD ACROSS THE TN VALLEY TODAY AND
SETTLE DIRECTLY OVER NC AND VA TONIGHT. THE HIGH WILL DRIFT OFFSHORE
MON...AHEAD OF AN UPPER LEVEL TROUGH THAT WILL MOVE INTO OUR REGION
MON NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM SUNDAY...

A COMPACT AND VIGOROUS SHORTWAVE TROUGH CENTERED DIRECTLY OVER
CENTRAL NC AT 07Z WILL MOVE QUICKLY EAST AND OFFSHORE THE VA/NC
COAST BY 12Z. DESPITE LIMITED MOISTURE...THE VIGOROUS AND
CONCENTRATED LIFT AND PRESENCE OF THE COLD POOL ALOFT HAS ALSO
SUPPORTED THE RECENT DEVELOPMENT OF SCATTERED...FAST-MOVING (45-50
MPH) SHOWERS FROM THE EASTERN SANDHILLS TO THE COASTAL PLAIN. ANY
SUCH SHOWER ACTIVITY WILL COME TO AN ABRUPT END/MOVE EAST BEFORE
DAYBREAK...SO SUBSIDENCE AND CLEARING IN STRONG HEIGHT RISES ALOFT...
AND 1025 MB SURFACE HIGH PRESSURE BUILDING SOUTHEAST FROM THE UPPER
MIDWEST...WILL OTHERWISE OVERSPREAD OUR REGION TODAY. A PERIOD OF
BREEZY NORTHWEST WINDS CAN BE EXPECTED AS THE MIXED LAYER DEEPENS
THIS MORNING AND TAPS INTO 20 KT WINDS JUST ABOVE THE
SURFACE...MAINLY OVER THE COASTAL PLAIN...BEFORE LESSENING AS THE
PRESSURE GRADIENT AND CAA RELAXES THIS AFTERNOON. PROJECTED 00Z LOW
LEVEL THICKNESSES AROUND 1350 METERS WILL SUPPORT NOTICEABLY COOLER
CONDITIONS DESPITE THE ABUNDANT SUNSHINE...GENERALLY IN THE MIDDLE
60S.

TONIGHT: THE APPROACH OF A DEAMPLIFYING UPPER WAVE THAT WAS LOCATED
OVER WESTERN OK THIS MORNING...AND A COMPLEX UPPER TROUGH AMPLIFYING
SOUTHEASTWARD FROM CENTRAL CANADA...WILL RESULT IN INCREASING HIGH
CLOUDS FROM THE WEST...PARTICULARLY AFTER MIDNIGHT. WITH THE CENTER
OF THE SURFACE HIGH EXPECTED TO BE DIRECTLY OVERHEAD...CALM AND
INITIALLY IDEAL RADIATIONAL COOLING CONDITIONS WILL SUPPORT QUICKLY
FALLING TEMPERATURES AFTER SUNSET...WITH A SLOWER FALL OR NEUTRAL
TENDENCY AS THE CIRRUS SPREAD EAST LATE. PROJECTED 12Z MON LOW LEVEL
THICKNESSES BETWEEN 1345-1350 METERS SHOULD SUPPORT LOWS MOSTLY IN
THE MIDDLE AND UPPER 30S...TO AROUND 40 DEGREES IN URBAN
AREAS...SUPPORTIVE OF PATCHY FROST IN THE TYPICALLY COOLER AREAS.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 340 AM SUNDAY...

SURFACE HIGH PRESSURE WILL MOVE OFFSHORE...AS THE HEIGHT FALLS ALOFT
ATTENDING THE UPPER TROUGH AMPLIFYING OUT OF CENTRAL CANADA SPREAD
SOUTHEASTWARD. RETURN FLOW AROUND THE HIGH WILL PROMOTE BOTH
MODERATING TEMPERATURES AND INCREASING STRATOCUMULUS...THE LATTER
MOST NOTABLY EAST OF INTERSTATE 95. CONSIDERABLE HIGH CLOUDS ARE
ALSO EXPECTED...AS THE UPPER JET AXIS ACCOMPANYING THE AMPLIFYING
TROUGH SETTLE OVERHEAD. HIGHS ABOUT 3 DEGREES ABOVE THOSE OF SUNDAY -
IN THE UPPER 60S...TO AROUND 70 DEGREES OVER THE SOUTHERN TIER. THE
OVERNIGHT PASSAGE OF A LEAD MID LEVEL TROUGH AND ASSOCIATED MID
LEVEL MOIST AXIS MON NIGHT WILL RESULT IN A BAND OF MID CLOUDS AND
VIRGA...BUT A STILL VERY DRY AIRMASS BELOW 10 THOUSAND FT SHOULD
PRECLUDE ANY PRECIPITATION FROM REACHING THE GROUND. NOT AS
COOL...WITH LOWS MAINLY IN THE UPPER 40S.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 315 AM SUNDAY...

SHORTWAVE ENERGY CURRENTLY OVER THE CANADIAN ROCKIES WILL DIVE
THROUGH THE MIDWEST AND CROSS THE AREA EARLY TUESDAY...IMMEDIATELY
FOLLOWED BY ANOTHER WAVE...AND ITS ASSOCIATED COLD FRONT...DIGGING
THROUGH THE DEEPENING LONGWAVE TROUGH TUESDAY EVENING.  DURING THE
DAY...A WEST-SOUTHWESTERLY WIND AND LIMITED CLOUD COVER AHEAD OF THE
COLD FRONT WILL ALLOW TEMPS TO WARM BACK INTO THE UPPER 60S AND
LOWER 70S. AS THE COLD FRONT MOVES THROUGH TUESDAY EVENING...A SHOT
OF STRONG DCVA WILL HAVE TO OVERCOME LIMITED MOISTURE...PW BELOW
0.75"...IN ORDER TO TO SQUEAK OUT A FEW ISOLATED...LIGHT
SHOWERS...MAINLY ACROSS THE FAR NORTHERN COASTAL PLAIN WHERE
MOISTURE PROFILES ARE SLIGHTLY MORE CONDUCIVE FOR PRECIP.
HOWEVER...MODELS ARE ONLY GENERATING A HUNDREDTH OR TWO OF QPF IN
SPOTS...SO SLIGHT CHANCE POPS CONTINUE TO BE THE BEST BET.

BEHIND THE FRONT...A NORTHWESTERLY WIND WILL PERSIST THROUGH MOST OF
THE WEEK AS THE UPPER TROUGH CLOSES OFF INTO AN UPPER LOW OVER THE
MID-ATLANTIC COAST.  MODELS HAVE HINTED AT A FEW SHOWERS ON
WEDNESDAY AFTERNOON AS THE CORE OF THE COLD AIR ALOFT AND SOME VERY
WEAK INSTABILITY DEVELOPS.  HOWEVER...MOISTURE WILL STILL EB
SEVERELY LACKING AND JUST ENHANCE CLOUD COVER SEEMS MORE LIKELY.
THICKNESSES ARE FORECAST TO BRIEFLY TOUCH 1340M ON WEDNESDAY
MORNING...THEN CLIMB BACK TOWARD NORMAL VALUES AROUND 1360M BY THE
END OF THE WEEK AS THE UPPER BEGINS TO DRIFT NORTHEAST AWAY FROM THE
REGION.  THUS...HIGHS WILL BE COOLEST WEDNESDAY IN THE LOW TO MID
60S AND TREND BACK INTO THE UPPER 60S TO LOWER 70S.

THERE ARE SIGNIFICANT MODEL DIFFERENCES BY NEXT WEEKEND AS ENERGY
CROSSING THE CENTRAL US IS FORCED INTO THE DEEP SOUTH AND THEN
EITHER MOVES EAST ACROSS THE SOUTHEAST US (GFS SOLUTION) OR CUTS OFF
OVER THE GULF COAST (ECMWF SOLUTION).  WPC HAS A STRONG PREFERENCE
FOR THE ECMWF AND ITS ENSEMBLE MEAN.  EITHER WAY THE FORECAST WILL
REMAIN DRY AND NEAR NORMAL THROUGH THE END OF THE EXTENDED PERIOD.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 655 AM SUNDAY...

STRONG SUBSIDENCE BEHIND A POTENT SHORTWAVE TROUGH (DISTURBANCE)
ALOFT EXITING THE NC COAST THIS MORNING WILL RESULT IN CLEAR SKIES
TODAY. NORTHWESTERLY SURFACE WINDS WILL BECOME BRIEFLY GUSTY INTO
THE 15-20 KT RANGE BETWEEN 13-17Z...STRONGEST AND MOST FREQUENT AT
EASTERN TERMINALS...BEFORE LESSENING THIS AFTERNOON AND BECOMING
CALM AT SUNSET...AS HIGH PRESSURE BUILDS INTO...AND SETTLES OVER...
NC.

OUTLOOK: MOISTURE IN SSE RETURN FLOW WILL RESULT IN A GOOD CHANCE OF
SCATTERED TO BROKEN STRATOCUMULUS BASED AROUND 3000 FT - MAINLY
ALONG COASTAL AREAS - THOUGH THE WESTERN EDGE OF THIS CLOUDINESS
COULD BRUSH KFAY AND KRWI MON AFTERNOON. THE DEVELOPMENT OF AN UPPER
LOW OVER THE MIDDLE ATLANTIC STATES...AND ASSOCIATED PASSAGE OF A
SURFACE COLD FRONT...WILL RESULT IN A CHANCE OF SHOWERS TUE
AFTERNOON.

&&

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

&&

$$

SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...BLS
AVIATION...MWS



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