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Data updated Mon Apr 17 2006


FXUS62 KRAH 221616
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1109 AM EST THU FEB 22 2007

.SYNOPSIS...

A STRONG DRY COLD FRONT WILL MOVE EAST ACROSS CENTRAL NORTH
CAROLINA THIS AFTERNOON. WINDS WILL BE INCREASING THROUGH THE DAY
AS STRONG WINDS ALOFT UPSTREAM MIX DOWN TO THE SURFACE...
ESPECIALLY OVER THE NORTHWEST PIEDMONT. A WIND ADVISORY WILL BE
ISSUED FOR THE NORTHWEST PIEDMONT INCLUDING FORSYTH... GUILFORD...
DAVIDSON... RANDOLPH... AND ALAMANCE... VALID THROUGH MIDNIGHT
TONIGHT. 
&&

.SHORT TERM /REST OF TODAY/...

STRONG AND GUSTY WINDS... ASSOCIATED WITH A COLD FRONTAL PASSAGE 
THIS AFTERNOON... WILL BE THE PROBLEM OF THE AFTERNOON AND INTO THE 
NIGHT. THE STRONG COLD FRONT WAS APPROACHING NORTHWEST NORTH 
CAROLINA LATE THIS MORNING. THE FRONT WILL MOVE ACROSS CENTRAL NORTH 
CAROLINA THIS AFTERNOON. STRONG WINDS NOTED IN EXCESS OF 50 KNOTS AT 
H85 OVER THE OHIO VALLEY EXTENDING SE INTO THE NORTHERN NORTH 
CAROLINA MOUNTAINS LATE MORNING... WILL LIKELY OVERSPREAD THE 
NORTHWEST PIEDMONT THIS AFTERNOON. 

DURING MAXIMUM HEATING... SOME OF THE STRONGER WINDS WILL 
MIX DOWN TO THE SURFACE... ESPECIALLY OVER THE MORE ELEVATED 
PIEDMONT ZONES IN THE PIEDMONT TRIAD REGION INCLUDING 
WINSTON-SALEM... GREENSBORO... HIGH POINT... LEXINGTON... AND 
BURLINGTON. SUSTAINED WINDS OF 20 TO 30 MPH... WITH GUSTS TO BETWEEN 
45 AND 50 MPH POSSIBLE THERE. THESE STRONG GUSTY WINDS MAY LAST WELL 
AFTER SUNSET WITH THE STRONG CAA EXPECTED THROUGH AT LEAST MIDNIGHT. 

EAST AND SOUTH OF THE NORTHWEST PIEDMONT... THE WINDS WILL BECOME 
STRONG AND GUSTY THIS AFTERNOON. THEY SHOULD REMAIN BELOW THE WIND 
ADVISORY THRESHOLD OF GUSTS TO 46 MPH OR GREATER. FOR NOW... WILL 
CARRY WIND GUSTS TO NEAR 40 MPH OVER THESE AREAS INCLUDING RDU... 
FAY... RWI... RZZ... AND GSB. 

THE SURFACE TEMPS SHOULD ALSO SOAR TO NEAR RECORD LEVELS ALONG AND 
AHEAD OF THE FRONT. EXPECT HIGHS TO REACH OR EXCEED 70 AT MANY 
LOCATIONS... POSSIBLY 75 OVER THE SANDHILLS. 
&&

.CLIMATE...

RECORD HIGHS FOR FEBRUARY 22

RDU... 71 (1955).
GSO... 73 (1930).

&&

.FIRE WEATHER...

RELATIVE HUMIDITY VALUES WILL DIP TO AROUND 25 PERCENT NW THIS
AFTERNOON... AND 25-35 PERCENT ELSEWHERE. NO RED FLAG WARNING IS
EXPECTED AT THIS TIME DUE TO ONLY MARGINALLY DRY FUELS AND
EXPECTED MARGINALLY LOW RELATIVE HUMIDITY VALUES. 

ONLY SLOW RELATIVE HUMIDITY RECOVERY EXPECTED TONIGHT AS THE
SURFACE WINDS STAY UP. 

VERY DRY RELATIVE HUMIDITIES EXPECTED FRIDAY (15-20) PERCENT...
BUT WINDS WILL DECREASE BELOW RED FLAG CRITERIA. 

&&


.PREV DISCUSSION...
/ISSUED 630 AM EST THU FEB 22 2007/ 

SHORT TERM /REST OF TODAY/...

QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR NORTHERN PIEDMONT AND
COASTAL PLAIN. MOISTURE POOLING ALONG A WEAK STATIONARY FRONT AND
LIGHT WINDS HAS SET THE STAGE FOR WIDESPREAD DENSE FOG OVER THE
NORTHERN CWA. VISIBILITIES WILL IMPROVE AROUND 9AM OR SO AS MIXING
BEGINS AND WESTERLY WINDS INCREASE.

ALL UPDATED PRODUCTS HAVE ALREADY BEEN SENT.

PREV DISCUSSION...
/ISSUED 321 AM EST THU FEB 22 2007/ 

SHORT TERM /TODAY THROUGH SATURDAY/...
A WEAK SFC LOW CONTINUES TO MEANDER OVER THE NORTHERN PIEDMONT EARLY
THIS MORNING. THIS LOW IS ANCHORED ON AN ILL DEFINED STATIONARY
FRONT DRAPED ACROSS NC. SHWR AND TSTM ACTIVITY THAT HAS OCCURRED
FROM ROXBORO TO ROCKY MOUNT IS DIMINISHING AND MOVING OUT OF THE
AREA AS A WEAK SHORTWAVE PASSES THROUGH. NO FURTHER DEVELOPMENT
EXPECTED UPSTREAM SO NO POPS MENTIONED THIS MORNING. AREAS OF
PATCHY DENSE FOG AND LOW STRATUS WILL PERSIST UNTIL A FEW HOURS
AFTER SUNRISE DUE TO MOISTURE POOLING ALONG THE FRONT. WILL
CONTINUE TO MONITOR OBSERVATIONS FOR THE POSSIBILITY OF A DENSE
FOG ADVISORY.

A MUCH STRONGER FRONT...ANALYZED FROM LAKE MICHIGAN TO NE ARKANSAS...
WILL RAPIDLY TRANSLATE EAST INTO THE AREA TODAY AS A CLIPPER
SHORTWAVE MOVES FROM THE GREAT LAKES INTO THE MID ATLANTIC. WINDS
BECOME BREEZY TO WINDY BEHIND THE FRONT THIS AFTERNOON. THERE ARE
TWO REASONS FOR THIS. THE FIRST IS A TIGHTENING PRESSURE GRADIENT
THIS AFTERNOON AS SFC LOW PRESSURE DEEPENS OFF THE NJ COAST. THE
SECOND IS STRONG WESTERLY TO NORTHWESTERLY UPPER FLOW ASSOCIATED
WITH THE SHORTWAVE ENERGY. MODEL FORECAST SOUNDINGS SHOW A DRY
ADIABATIC PROFILE UP TO NEAR 750MB. WINDS THROUGHOUT MOST OF THE
LAYER ARE AROUND 40 KTS...WITH 45-50 KTS AT THE VERY TOP OF THE
MIXED LAYER. IN ADDITION...WINDS JUST 1500 FT ABOVE THE SFC
STRENGTHEN TO 30-35 KTS BY MID AFTERNOON. THEREFORE...SUSTAINED
WINDS NEAR 25 MPH WITH FREQUENT GUSTS TO 40 MPH ARE EXPECTED THIS
AFTERNOON. THESE VALUES ARE SLIGHTLY BELOW WIND ADVISORY CRITERIA
(SUSTAINED 25/GUSTS 45)...HOWEVER WILL REISSUE A SPECIAL WEATHER
STATEMENT TO HIGHLIGHT THE EXPECTED CONDITIONS.

ASIDE FROM THE WINDY WEATHER...TODAY WILL BE QUITE WARM. STRONG
DOWNSLOPE FLOW ALONG WITH THICKNESSES 30-35M ABOVE CLIMO THROUGH
MIDDAY SHOULD PRODUCE HIGHS IN THE UPPER 60S TO LOWER 70S. COLD
AIR ADVECTION DOES NOT KICK IN UNTIL VERY LATE THIS AFTERNOON.

COLD AIR ADVECTION TO DOMINATE TONIGHT. THIS SHOULD KEEP THE
BOUNDARY LAYER MIXED WITH BREEZY CONDITIONS CONTINUING FOR MOST
OF THE NIGHT. STAYED ON THE WARMER SIDE OF THE GUIDANCE WITH WINDS
STAYING UP. LOW 30S NORTH TO MID 30S SOUTH EXPECTED BY FRIDAY
MORNING.

HIGH PRESSURE CENTERED NEAR HUDSON BAY RIDGES INTO CENTRAL NC ON
FRIDAY. DRY WEATHER AND NEAR NORMAL TEMPS ARE IN THE FORECAST.
LIGHT WINDS AND LOW DEWPOINTS FRIDAY NIGHT SHOULD ALLOW TEMPS TO
DROP INTO THE MID AND UPPER 20S. 

NORTHEAST US TROUGH LIFTS OUT ON SATURDAY...ALLOWING SHORTWAVE
RIDGE TO ENTER THE AREA. SFC HIGH SHIFTS EAST IN RESPONSE...TURNING
OUR WINDS SOUTHERLY BY AFTERNOON. HIGHS A DEGREE OR TWO ABOVE
CLIMO EXPECTED.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
FRONTAL SYSTEM WILL APPROACH CENTRAL NC SATURDAY NIGHT AND CROSS THE 
AREA SUN. DECENT SLY FLOW AHEAD OF SYSTEM COUPLED WITH SUPPORT ALOFT 
SUGGEST SHOWERS LIKELY AHEAD OF FRONTAL SYSTEM. PROJECTED WIND FIELD 
IMPRESSIVE WITH GFS INDICATING 50KTS AT 3K FT. HOWEVER AIRMASS IS 
RATHER STABLE. PREVIOUS FORECAST OF CHANCE THUNDER FOR THE AFTERNOON 
HOURS DIFFICULT TO IMPROVE UPON. MODEL TIMING SUGGEST THAT PRECIP 
CHANCES GREATEST DURING THE DAYLIGHT HOURS SUN...WITH RAIN CHANCES 
TAPERING OFF WEST-TO-EAST LATE SUN INTO SUN EVENING. 

WESTERLY FLOW BEHIND SYSTEM WILL ADVECT DRIER AIR BUT AIRMASS 
APPEARS TO BE JUST SLIGHTLY COOLER WITH BULK OF COOL/COLD AIR ACROSS 
THE GREAT LAKES INTO NEW ENGLAND. POTENTIAL FOR A NOTICEABLE COOL 
DOWN BY MID WEEK AS NORTHERN STREAM S/W CROSSES TO OUR 
NORTH...TEMPORARILY AMPLIFYING TROUGH OVER REGION. LOWERED MAX TEMPS 
WED DOWN A CATEGORY FROM PREVIOUS FORECAST. DEEP WEST-NW FLOW 
SUGGEST AIRMASS OVER CENTRAL NC WILL LACK MOISTURE TO GENERATE 
PRECIP MON-WED.

AVIATION /08Z-06Z/...
A DIFFUSE STATIONARY FRONT AND WEAK LOW PRESSURE OVER THE AREA HAS 
ALLOWED LOW LEVEL MOISTURE TO POOL OVER CENTRAL NC OVERNIGHT.  THIS 
HAS LED TO AREAS OF FOG AND STRATUS... ESPECIALLY IN AREAS HAVING 
EXPERIENCED SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS...MAINLY 
KRWI. THESE CONDITIONS WILL LIKELY PERSIST UNTIL DAYBREAK WITH IFR 
OR LIFR AT KRWI...KFAY...AND POSSIBLY KRDU. OTHERWISE...VFR 
CONDITIONS ARE EXPECTED AT ALL TERMINAL SITES BY MID MORNING THU 
INTO THU EVENING. 

A DRY COLD FRONT WILL APPROACH FROM THE NW AND CROSS THE AREA THU 
AFTERNOON.  WNW SURFACE WINDS ARE EXPECTED TO BECOME QUITE GUSTY BY 
AFTERNOON...POSSIBLY UP TO 35 KNOTS. COLDER AIR WILL PUSH INTO THE 
AREA THU EVENING.  -RFG/WSS

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ021>023-038-
039.

&&

$$

SYNOPSIS...
SHORT TERM...BADGETT