-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 090041
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
741 PM EST SUN DEC 8 2013

.SYNOPSIS... COLD SURFACE HIGH PRESSURE WILL HOLD ON TONIGHT... THEN
BEGIN TO GIVE WAY MONDAY. A COLD FRONT WILL SLOWLY MOVE ACROSS THE
REGION MONDAY NIGHT AND TUESDAY.

&&

.NEAR TERM /TONIGHT/...
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AS OF 733 PM SUNDAY...

A FREEZING RAIN ADVISORY REMAINS IN EFFECT FOR THE PIEDMONT TRIAD
REGION THROUGH 500 AM.

THERE HAVE BEEN NO REPORTS OF ICING ON AREA ROADS...HOWEVER SOME
LIGHT ICING CONTINUES ON ELEVATED SURFACES MAINLY ALONG AND NORTH OF
INTERSTATE 40 IN THE WINSTON-SALEM TO GREENSBORO AREAS. LOCAL
TEMPERATURES HAVE BEEN HOVERING BETWEEN 31 AND 32...WITH OBVIOUSLY A
WARM GROUND KEEPING ANY ACCRUAL UP A FEW FEET ABOVE THE SURFACE.
STORM TOTAL PRECIPITATION AMOUNTS (LIQUID) HAVE BEEN UNDER A QUARTER
INCH...WITH ONLY UP TO 1/16 INCH OF ICING REPORTED IN NORTHERN
FORSYTH COUNTY.

WE WILL MAINTAIN THE FREEZING RAIN ADVISORY PER DIRECTIVE AS ANY
FREEZING RAIN MENTION REQUIRES AN ADVISORY. SOME LIGHT ACCRUAL MAY
CONTINUE OVERNIGHT BUT AS TEMPERATURES REACH 32...THERE IS AS MUCH
MELTING AS FREEZING. TEMPS SHOULD REACH 32.5 OR HIGHER AFTER 500
AM...THEN RISE TO NEAR 40 BY NOON MONDAY ELIMINATING THE THREAT.

ELSEWHERE...MOST OF THE NEXT ROUND OF RAIN IS EXPECTED TO LIFT UP
ALONG AND WEST OF THE BLUE RIDGE...POSSIBLY CLIPPING OUR NW ZONES
OVERNIGHT. THIS LEAVES MOST OF CENTRAL AND EASTERN NC IN THE
MIST/DRIZZLE LOW OVERCAST ASSOCIATED WITH THE CURRENT CLASSICAL CAD
EVENT.

THE MAIN PROBLEM LATER TONIGHT INTO MONDAY WILL BE AREAS OF DENSE
FOG AS THE WARM AIR BEGINS TO OVERTAKE THE COLD SURFACE AIR. WE MAY
NEED DENSE FOG ADVISORIES FOR MANY AREAS LATER TONIGHT INTO A
PORTION OF MONDAY IN LATER ISSUANCES.
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&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 255 PM SUNDAY...

MON AND MON NIGHT: SOME THINNING OF THE SATURATED CAD LAYER IS
LIKELY...PARTICULARLY OVER THE COASTAL PLAIN WHERE SREF MEAN AND NMM
BUFR SOUNDINGS DEPICT JUST A THIN SATURATED LAYER BETWEEN 500-1500
FT BY MON AFTERNOON. SOME BINOVC AND SCATTERING ARE ACCORDINGLY
LIKELY OVER THE COASTAL PLAIN AND EASTERN SANDHILLS WHERE THIS
DRYING OCCURS...WHILE LINGERING DEEPER COLD AIR DAMMING REGIME AND
ASSOCIATED OVERCAST AND PERIODS OF DRIZZLE...TRAPPED BY THE STILL
STOUT CAD INVERSION...HOLDS OVER THE PIEDMONT. TEMPERATURES WILL
CONSEQUENTLY VARY SIGNIFICANTLY FROM THE 40S OVER THE NW PIEDMONT TO
60S IN THE COASTAL PLAIN. ASIDE FROM THE DRIZZLE...NO APPRECIABLE
MEASURABLE RAIN IS EXPECTED UNTIL A DEAMPLIFYING MID LEVEL TROUGH
INDUCES WEAK FRONTAL WAVE DEVELOPMENT OVER THE LINGERING WEDGE FRONT
OVER THE CAROLINAS...AND PRODUCES A TENTH OR TWO OF RAIN OVERNIGHT.
LOWS IN THE 40S...TO LOWER 50S OVER THE SANDHILLS AND SOUTHERN-
CENTRAL COASTAL PLAIN.

MODEL RUNS NOW IN BETTER AGREEMENT WITH THE FRONTAL PASSAGE ON
TUESDAY... WITH A FRONTAL WAVE DEVELOPING IN THE VICINITY OF THE
CAROLINAS. RAINFALL WILL END FROM WEST TO EAST BY 00Z WED AS THE
SYSTEM MOVES OFF THE EAST COAST. COLD ADVECTION BEHIND THE FRONT
WITH NORTH TO NORTHEAST FLOW WILL LEAD TO INITIALLY FLAT-LINED TEMPS
FALLING DURING THE DAY. COLDER LOWS IN THE 20S.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 250 PM SUNDAY...

A WEAK AREA OF HIGH PRESSURE BUILDS IN TO THE MID-ATLANTIC ON
WEDNESDAY...FOLLOWED BY A MUCH STRONGER AREA OF HIGH PRESSURE AND
REINFORCING SHOT OF COLD AIR BUILDS FOR FRIDAY... KEEPING TEMPS
BELOW NORMAL AND IN THE 40S... WITH DRY CONDITIONS TO END THE WEEK.

MODELS INDICATING A SOUTHERN STREAM SYSTEM AT THE END OF THE PERIOD.
BOTH MODELS DEVELOP AN INITIAL SURFACE TROUGH NEAR THE GULF ON
SATURDAY WITH A AN INITIAL SHORTWAVE MOVING OUT OF THE FOUR
CORNERS REGION... THIS IS FOLLOWED CLOSELY BY A SECOND, STRONGER
SHORTWAVE IN THE GFS... AND A SURFACE LOW DEVELOPING AND MOVING
NORTHEAST OVER THE AREA SUNDAY.. THE ECMWF HAS SOLUTIONS HAVE
VARIED CONSIDERABLY WITH THIS SECOND SHORTWAVE... RESULTING IN
VARIATIONS IN PRECIPITATION AMOUNT AND TIMING. THE 12Z RUN IS MUCH
CLOSER IN LINE WITH THE GFS. DESPITE DIFFERENCE IN THE DETAILS...
THE RESULTS SUPPORT PRECIPITATION CHANCES FOR THE WEEKEND.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
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AS OF 745 PM SUNDAY...

24-HR TAF PERIOD: ADVERSE AVIATION CONDITIONS WILL PREVAIL THROUGH
THE TAF PERIOD. EXPECT IFR/LIFR CEILINGS THIS EVENING TO FURTHER
LOWER TO LIFR/VLIFR OVERNIGHT...WITH A POTENTIAL FOR DENSE FOG BY
SUNRISE (12Z MON). ADDITIONALLY...PERIODS OF FREEZING DRIZZLE WILL
REMAIN POSSIBLE AT THE INT/GSO TERMINALS THROUGH 09Z MON. EXPECT
MARGINAL IMPROVEMENT AT BEST DURING THE DAY MONDAY GIVEN NO
SIGNIFICANT CAD EROSION MECHANISMS...WITH PERHAPS SOME DIURNAL
IMPROVEMENT IN CEILINGS TO IFR OR LOW-END MVFR (600-1200 FT AGL)
DURING THE AFTERNOON.

LOOKING AHEAD: ADVERSE CONDITIONS (IFR/MVFR AND PERHAPS LIFR)
ASSOC/W THE COLD AIR DAMMING WEDGE WILL MOST LIKELY LINGER THROUGH
THE DAY TUESDAY AS A COLD FRONT APPROACHES FROM THE WEST. VFR
CONDITIONS WILL RETURN TUE NIGHT AS DRY HIGH PRESSURE BUILDS INTO
THE REGION FROM THE WEST. VFR/DRY CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH THE REMAINDER OF THE WORK WEEK. -VINCENT
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&&

.RAH WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 5
AM EST MONDAY FOR NCZ007-008-021>024-038.

&&

$$

SYNOPSIS...PWB
NEAR TERM...MWS/PWB
SHORT TERM...MWS/SEC
LONG TERM...SEC
AVIATION...VINCENT