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000
FXUS62 KRAH 240631
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
231 AM EDT FRI MAY 24 2013

.SYNOPSIS...
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A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
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&&

.NEAR TERM /TODAY/...
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AS OF 230 AM FRIDAY...

AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION.
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&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
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AS OF 240 PM THURSDAY...

TONIGHT: WINDS WILL REMAIN BLUSTERY WHICH WILL HELP TO OFFSET
RADIATIONAL COOLING A BIT AS THICKNESSES SUPPORT LOWS NEAR 40
DEGREES BUT WILL GO A BIT CONSERVATIVE IN THE LOWER 40S. STILL VERY
POSSIBLE TO BREAK THE LOW TEMPERATURE RECORDS AT BOTH RDU AND GSO
WHICH ARE BOTH 43 DEGREES. -ELLIS

SATURDAY THROUGH SUNDAY NIGHT...

A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.

TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.

MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
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&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...

12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W
TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING
TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS
ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A
LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN
AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW
ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES
ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID
WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE
TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN
WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING
CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR
NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO
THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER
80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS
VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90.


&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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AS OF 210 AM FRIDAY...

JUST A LITTLE LIGHT AND INSIGNIFICANT RAIN REMAINS FROM EARLIER
SHOWERS AND STORMS...AND THIS TOO SHOULD FURTHER DIMINISH DURING THE
NEXT COUPLE OF HOURS IN THE VICINITY OF KFAY/KRDU/KGSO. OTHERWISE...
AREAS OF STRATUS AND FOG ARE LIKELY TO AFFECT KFAY...KRWI...AND
PERHAPS AS FAR WEST AS KRDU THROUGH DAYBREAK...AS LOW LEVEL MOISTURE
WILL REMAIN HIGH AND WINDS LIGHT AHEAD OF A DIFFUSE COLD FRONT
APPROACHING FROM THE WEST. SOME LINGERING 7-9 THOUSAND FT CLOUD
COVER AND A FEW SHOWERS THROUGH MIDDAY AT EASTERN TERMINALS CAN ALSO
BE EXPECTED...WITH OTHERWISE CLEARING CONDITIONS AND A BREEZY AND
GUSTY NORTHWESTERLY WIND DEVELOPING BY AROUND 15Z. WINDS WILL
DIMINISH AROUND SUNSET.

OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
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&&

.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.

RECORD MIN TEMP/YEAR SET      MAY 25TH            MAY 26TH

RDU                           43 / 1967           43 / 1979

GSO                           43 / 1956           42 / 1930


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

&&

$$

SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...ELLIS/WSS
LONG TERM...WSS
AVIATION...MWS
CLIMATE...RAH