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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 091755
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1255 PM EST TUE FEB 9 2010

.SYNOPSIS...
-- Changed Discussion --
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH THIS
AFTERNOON...AND MOVE NORTHEAST MOVING OFF THE NORTH CAROLINA COAST
TONIGHT. STRONG WINDS BEHIND A COLD FRONT WILL AFFECT THE
AREA ON WEDNESDAY.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM TUESDAY...

HAVE CANCELED THE WINTER WEATHER ADVISORY AS THE LATER ARRIVAL OF
THE PRECIP HAS ALLOWED TEMPS TO WARM INTO THE MID 30S. WET BULB
TEMPS AT 14Z/9 AM WERE NEAR 30 ACROSS THE NW PIEDMONT BUT SHOULD
WARM TO NEAR FREEZING BY THE TIME THE APPRECIABLE RAINFALL OCCURS.
MAY STILL SEE A BRIEF PERIOD OF SNOW/FREEZING RAIN AT PRECIP ONSET
ESPECIALLY NORTH OF WINSTON-SALEM AND GREENSBORO BUT AS PRECIP
INTENSITY INCREASES...SHOULD SEE PRECIP CHANGE TO ALL LIQUID. DELAY
OF PRECIP APPEARS TO BE CAUSED BY DIFFLUENT 850MB DEPICTED ON THE
12Z UPPER AIR ANALYSIS. STILL EXPECT PRECIP TO BLOSSOM OVER REGION
BETWEEN 15-18Z AS 925-850MB FLOW INCREASE...RESULTING IN
STRONGER ISENTROPIC LIFT. THUS WILL MAINTAIN CATEGORICAL POPS
FOR THIS AFTERNOON. MASSAGED MAX TEMPS A LITTLE BUT STILL ACHIEVED
MAX TEMPS IN THE MID 30S NW TO THE MID 40S SE. IF PRECIP IS DELAYED
UNTIL EARLY AFTERNOON INT HE E-NE...MAY NEED TO ADJUST MAX TEMPS UP
2-3 DEGREES.

TONIGHT...MAY NEED TO RESURRECT THE ADVISORY FOR THE NW PIEDMONT
LATER THIS EVENING/EARLY OVERNIGHT AS COLDER AIR WILL INFILTRATE THE
REGION BEHIND THE EXITING LOW PRESSURE SYSTEM. BEST MOISTURE
CONFINED TO THE LOWEST 6000-8000FT SO EXPECTING MAINLY LIGHT RAIN OR
DRIZZLE. AS TEMPS DROP TO NEAR OR SLIGHTLY BELOW FREEZING...COULD
SEE A 2-4 HOUR PERIOD OF FREEZING PRECIP. WILL RE-EVALUATE THIS
SCENARIO WITH THE LATEST MODEL GUIDANCE PLUS SEE HOW WELL MODELS
VERIFY 18Z CONDITIONS. FINALLY...MAY SEE SUFFICIENT DRYING OF ROAD
PAVEMENTS TONIGHT AS W-NW WINDS EXPECTED TO INCREASE DUE TO
TIGHTENING OF PRESSURE GRADIENT CAUSED BY DEEPENING SURFACE LOW OFF
THE DELMARVA  COAST AND THE APPROACH OF A HIGH PRESSURE SYSTEM FROM
THE WEST. INSTEAD OF AN ADVISORY FOR BLACK ICE...MAY BE ABLE TO GET
BY WITH A SPS.


&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 330 AM TUESDAY...

...HIGH WIND WATCH IN EFFECT FOR ALL OF CENTRAL NC ON
WEDNESDAY...

THE INTENSE MID LEVEL VORTEX... WITH HEIGHTS 3-4 STANDARD DEVIATIONS
BELOW NORMAL... CROSSES SOUTHERN VIRGINIA WEDNESDAY MORNING THROUGH
EARLY AFTERNOON AS A SURFACE LOW BOMBS JUST OFF THE NJ COAST.
THERE IS OVERWHELMING MODEL CONSENSUS OF A DEEP(DOWN TO 850MB)
STRATOSPHERIC OZONE INTRUSION WITHIN THE DRY SLOT AND ALONG THE
SOUTHERN/WESTERN QUADRANT OF THE CLOSED CYCLONE. WITH SOUNDINGS
SHOWING MIXING TO 775MB WEDNESDAY AFTERNOON...THIS INTRUSION
WILL LIKELY DRAG/MIX DOWN SOME OF THE 50 TO 60KT WINDS TO THE
SURFACE. WHILE A STRONGLY STABLE BL SHOULD CERTAINLY PREVENT FULL
REALIZATION OF THESE STRONG WINDS TO THE SFC...WIDESPREAD WIND GUSTS
OF 35 TO 40 MPH ARE EXPECTED...WITH THE POTENTIAL TO SEE SOME
LOCATIONS GUSTS OVER 40 MPH. WIND SPEEDS OF THIS MAGNITUDE ARE VERY
ALARMING CONSIDERING THE SATURATED/SOGGY SOILS ACROSS THE AREA...AS
TREE ROOTS WILL BE VERY VULNERABLE. COULD SEE WIDESPREAD WIND DAMAGE
FROM UPROOTED TREES. THUS WILL ISSUE A HIGH WIND WATCH FOR ALL OF
CENTRAL NC BEGINNING AT 6AM WEDNESDAY THROUGH 9PM.

WILL STAY ON THE COOL SIDE OF GUIDANCE FOR HIGHS WEDNESDAY...36-41
...WHICH AGREES WELL WITH LOCAL RESEARCH GIVEN THE LOW LEVEL DRY
ADIABATIC PROFILE. WIND CHILLS ARE LIKELY TO BE IN THE TEENS OVER
MUCH OF THE AREA AT LEAST THROUGH WEDNESDAY MORNING. WINDS REMAIN
VERY BRISK THROUGH MUCH OF WEDNESDAY NIGHT AS THE SURFACE CYCLONE
PULLS EAST AWAY FROM THE NORTHEAST COAST OVERNIGHT. LOWS 22-27.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 240 AM TUESDAY...

OVERALL...THE LONG TERM PERIOD IS SHAPING UP TO BE DRY...WITH BELOW
NORMAL TEMPS...AS NORTHWESTERLY FLOW PERSISTS COURTESY OF A STRONG
POLAR VORTEX ACROSS EASTERN CANADA.

THURSDAY THROUGH FRIDAY: HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST ON THURSDAY AS A STRONG LOW PRESSURE SYSTEM CONTINUES TO
MOVE NORTHEAST AWAY FROM THE CAROLINA COAST. THIS WILL RESULT IN AN
INCREASED PRESSURE GRADIENT WHICH WILL LEAD TO ANOTHER BREEZY DAY ON
THURSDAY (ALTHOUGH WINDS WILL BE WEAKER THAN EXPERIENCED ON
WEDNESDAY). MID/HIGH CLOUDS ARE EXPECTED TO INCREASE THROUGH FRIDAY
AS THE FLOW ALOFT PICKS UP AHEAD OF THE NEXT SYSTEM. THICKNESS
VALUES ARE PROGGED TO RANGE BETWEEN 1285-1295M...THEREFORE AM ONLY
EXPECTING HIGHS TO BE IN THE LOWER TO MID 40S...WITH LOWS IN THE
20S.

FRIDAY NIGHT THROUGH SATURDAY: A SOUTHERN STREAM WAVE IS PROGGED TO
TRACK ACROSS THE SOUTHEAST STATES FRIDAY NIGHT AND SHIFT OFFSHORE BY
MIDDAY SATURDAY. DURING THE SAME TIME FRAME...NORTHERN STREAM ENERGY
IS PROGGED TO DROP DOWN THROUGH THE DAKOTAS AND INTO THE
MIDWEST/OHIO VALLEY...SUPPRESSING THE SOUTHERN STREAM WAVE TO OUR
SOUTH. THEREFORE...THE TRACK OF THIS WAVE AND ITS ASSOCIATED SURFACE
LOW IS EXPECTED TO BE FAR ENOUGH SOUTH THAT CENTRAL NORTH CAROLINA
SHOULD REMAIN PRECIP FREE FROM THIS SYSTEM. IN FACT...MODELS
CONTINUE TO SHOW THE REGION REMAINING DRY WITH THIS SYSTEM...HOWEVER
A SLIGHT NORTHERN SHIFT OF THE TRACK COULD LEAD TO SOME LIGHT PRECIP
ACROSS THE SANDHILLS. FORECAST SOUNDINGS AND PARTIAL THICKNESS
VALUES INDICATE ANY PRECIP THAT WOULD FALL IN THIS REGION WOULD BE
IN THE FORM OF SNOW. HOWEVER...FOR NOW WILL SHOW A DRY FORECAST FOR
THIS PERIOD...BUT THIS WILL HAVE TO MONITORED CLOSELY OVER THE NEXT
COUPLE OF DAYS. TEMPS WILL REMAIN QUITE CHILLY...WITH LOWS REMAINING
IN THE 20S AND HIGHS GENERALLY IN THE UPPER 30S TO LOWER 40S.

SUNDAY THROUGH MONDAY: MORE DRY AND AND COLD WEATHER EXPECTED FOR
THIS PORTION OF THE FORECAST. HOWEVER...BOTH THE GFS AND ECMWF SHOW
A CLIPPER DROPPING ACROSS THE UPPER MIDWEST INTO THE OHIO VALLEY BY
MONDAY...ALTHOUGH THERE ARE SIGNIFICANT TIMING AND STRENGTH
DIFFERENCES. NEVERTHELESS...MODELS PROG MOST OF THE ENERGY TO REMAIN
NORTH OF THE REGION...THEREFORE WILL MAINTAIN THE DRY FORECAST AND
BELOW NORMAL TEMPS.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 1245 PM TUESDAY...

AT 12 NOON AN AREA OF LOW PRESSURE WAS LIFTING NE OVER EASTERN SC.
THIS FEATURE WILL CONTINUE TO MOVE NE THIS AFTERNOON AND THIS
EVENING OVER THE COASTAL PLAIN OF THE CAROLINAS. A TROUGH ASSOCIATED
WITH THE SURFACE FLOW WILL AID TO FOCUS THE MAJORITY OF THE
PRECIPITATION OVER THE SANDHILLS...EASTERN PIEDMONT AND THE COASTAL
PLAIN. WHILE THE NEAR SURFACE WINDS WILL SLOWLY VEER FROM E-NE TO SE
THEN TO WEST LATER TONIGHT WITH SPEEDS AT OR LESS THAN 5 KTS...WINDS
AT 2000FT WILL BE INCREASING TO AROUND 25KTS AND VEER FROM SLY TO
WLY. HAVE MENTIONED LLWS FOR THE TERMINALS AT KRDU...KFAY AND
KRWI.

AFTER 06Z WED...THE SURFACE LOW WILL STRENGTH RAPIDLY. THIS WILL
RESULT IN BLUSTERY WINDS BY 08-10Z ACROSS THE REGION. EXPECT
FREQUENT GUSTS NEAR 25 KTS BY 09Z.

A RATHER DEEP MID/UPPER LEVEL LOW WILL CROSS THE AREA ON WEDNESDAY.
MEANWHILE A DEEP LOW OFF THE DELMARVA COUPLED WITH AN AREA OF HIGH
PRESSURE TO OUR WEST WILL CREATE VERY STRONG WLY WINDS WED.
SUSTAINED AROUND AROUND 25KTS PROBABLE WITH GUSTS 40-45 KTS LIKELY.
WOULD NOT BE SURPRISED IF A FEW SITES NORTH OF HIGHWAY 64 REPORT
GUSTS AROUND 50KTS.

WINDS WILL GRADUALLY SUBSIDE WEDNESDAY NIGHT. VFR CONDITIONS
EXPECTED THU THROUGH SUNDAY. IT WILL REMAIN WINDY THURSDAY BUT NOT
AS STRONG AS WHAT IS EXPECTED WEDNESDAY.
-- End Changed Discussion --


&&

.RAH WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...CBL
NEAR TERM...WSS
SHORT TERM...CBL/HARTFIELD
LONG TERM...KRR
AVIATION...WSS