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000
FXUS62 KRAH 241718 CCA
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
110 PM EDT FRI MAY 24 2013

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION THROUGH THE
WEEKEND.

&&

.NEAR TERM /TODAY/...
AS OF 1025 AM FRIDAY...
12Z ANALYSIS SHOWS THAT CURRENT FORECAST FOR TODAY IS ON TRACK PER
PREV DISCUSSION (INCLUDED BELOW FOR REFERENCE). THE ONLY ADJUSTMENT
WILL BE INCREASING THE NW WINDS A LITTLE SOONER.  FORECAST SOUNDINGS
SHOW AVG BL WIND IN THE 24-28KT RANGE ACROSS MUCH OF CENTRAL NC
TODAY...AND THIS IS SUPPORTED BY TRENDS IN THE GSO OBSERVED
SOUNDING. WITH TEMPS ALREADY IN THE UPPER 60S TO AROUND 70...DEEP
MIXING IS UNDERWAY AND WE`RE ALREADY SEEING SFC GUSTS UP TO 25 KT
ACROSS OUR NW ZONES.  OTHERWISE...LINGERING LIGHT SHOWERS ACROSS OUR
NE ZONES ARE ADDRESSED IN CURRENT POP/WX GRIDS...SO NO CHANGES
THERE. THIS ACTIVITY IS EXPECTED TO WIND DOWN AND MOVE EAST OF OUR
CWA BY EARLY TO MID AFTERNOON.

PREV DISCUSSION 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. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...

HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.

CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...

PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.

SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.

&&

.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...

A BAND OF BKN CLOUDS WITH CIGS GREATER THAN 4K FT...ALONG WITH SOME
EMBEDDED SPRINKLES...IS QUICKLY MOVING EAST OF I-95. THIS IS
OCCURRING IN CONJUNCTION WITH A SECONDARY BOUNDARY MOVING ACROSS THE
AREA. DRIER AIR AS NOTED BY 20+ DEG DWPT DEPRESSIONS IS FOUND BEHIND
THIS BOUNDARY...ALONG WITH CLEARING SKIES. AS SUCH...LOOK FOR VFR
CONDITIONS TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD. THE OTHER
MAIN CONCERN IS GUSTY NW WINDS. THROUGH SUNSET...LOOK FOR NW WINDS
10-15 KT WITH GUSTS IN THE LOW 20S. AFTER SUNSET AND THROUGH 18Z
SAT...LOOK FOR CLEAR SKIES AND LIGHT WINDS.

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.

&&

.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH 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...NP
NEAR TERM...NP/MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...NP/MWS
CLIMATE...MLM