Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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163
FXUS62 KRAH 111522
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1022 AM EST THU FEB 11 2016

.SYNOPSIS...A NARROW AREA OF HIGH PRESSURE WILL EXTEND ACROSS
CENTRAL NC TODAY THEN DRIFT SOUTHWARD. AN UPPER LEVEL DISTURBANCE
WILL CROSS OUR REGION FRIDAY. AN ARCTIC HIGH PRESSURE SYSTEM WILL
SEND SOME OF THE COLDEST AIR THIS WINTER SEASON INTO CENTRAL NC FOR
THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM THURSDAY...

HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY AS A FRONTAL SYSTEM
RESIDES TO OUR SOUTH. THE UPPER LEVEL EASTERN CONUS TROUGH WILL
BEGIN TO WEAKEN TODAY BUT PLENTY OF COLD AIR STILL IN PLACE AS
THICKNESSES SUGGEST HIGH TEMPERATURES TODAY ONLY MAKING IT INTO THE
UPPER 30S ACROSS THE NORTH TO LOW 40S IN THE SOUTH. THIS PUTS
DAYTIME HIGHS 10-15 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. A
BIT BREEZY AGAIN THIS AFTERNOON WITH WINDS SUSTAINED IN THE 5-10 KT
RANGE GUSTING TO NEAR 15 KTS OR SO THIS AFTERNOON. EXPECT LOW
TEMPERATURES TONIGHT TO ONCE AGAIN BE IN THE LOW 20S ACROSS THE
NORTH. CLOUDS WILL INCREASE FROM THE SOUTHWEST TONIGHT LIMITING
COOLING ACROSS THE SOUTHERN COUNTIES...MID 20S IN THESE AREAS.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 350 AM THURSDAY...

...POTENTIAL INCREASING FOR A WINTRY MIX TO OCCUR ACROSS THE EASTERN
THIRD OF CENTRAL NC FRIDAY...

THE LATEST MODEL GUIDANCE HAS TRENDED WETTER ACROSS THE EASTERN
COUNTIES OF NC FRIDAY IN ASSOCIATION WITH A SEWD MOVING UPPER
DISTURBANCE. THIS UPPER FEATURE SHOULD INDUCE AN AREA OF LOW
PRESSURE TO DEVELOP ALONG THE SC COAST AND MOVE NEWD ALONG/OFFSHORE
OF THE NC COAST FRIDAY AFTERNOON-EARLY EVENING.

RH CROSS SECTIONS DEPICT PLENTY OF MOISTURE IN THE FAVORED ICE
NUCLEATION GROWTH ZONE THOUGH MOISTURE INITIALLY IS LACKING IN THE
LOWER LAYERS OF THE COLUMN. THESE LAYERS EVENTUALLY MOISTEN THANKS
TO PRECIP FALLING THROUGH THE COLUMN ALONG WITH LOW LEVEL WARM AND
MOIST AIR ADVECTION. BY MID-LATE MORNING...ATMOSPHERE APPEARS TO BE
SUFFICIENTLY MOIST TO GENERATE PRECIP.

LIFT WILL BE SUPPLIED BY A COUPLE OF SOURCES: ONE BEING LOW LEVEL
ISENTROPIC UPGLIDE AND THE OTHER INCREASING DIVERGENCE ALOFT IN
CONJUNCTION WITH THE NOSE OF A 130KT JET. THIS LIFT APPEARS TO BE
MAXIMIZED  OVER THE REGION LATE MORNING THROUGH EARLY AFTERNOON.

THE TEMPERATURE PROFILE SUGGEST THAT THE PRECIPITATION WILL
INITIALLY START OUT AS LIGHT SNOW. AS WARMER AIR STARTS TO
OVERSPREAD THE REGION FROM THE SOUTH... SHOULD SEE THE SNOW MIX WITH
SLEET THEN EVENTUALLY TRANSITION TO A SLEET/RAIN/SNOW MIXTURE BEFORE
ENDING LATE IN THE DAY. AT THIS TIME EXPECT MOST OF THE PRECIP TO
OCCUR OVER SECTIONS OF THE SANDHILLS INTO THE COASTAL PLAIN AND THE
FAR EASTERN PIEDMONT BETWEEN 10 AM AND 4 PM. OVER THE REST OF THE
PIEDMONT...EXPECTING JUST A FEW PATCHES OF LIGHT SNOW OR SNOW
FLURRIES.

IMPACTS CURRENTLY WILL BE LIMITED TO A QUICK ACCUMULATION ON
UNTREATED ROADS/PAVEMENTS WITH AMOUNTS VARYING FROM A DUSTING OVER
THE EASTERN SANDHILLS...EASTERN PIEDMONT AND SOUTHERN COASTAL
PLAIN...TO UP TO AN INCH OVER SECTIONS OF THE CENTRAL AND NORTHERN
COASTAL PLAIN.

HIGH TEMPS FRIDAY DEPENDENT ON PRECIP COVERAGE AND TYPE. HAVE
LOWERED MAX TEMPS IN THE EAST A FEW DEGREES FROM PREVIOUS FORECAST
IN ANTICIPATION OF BETTER PRECIP COVERAGE. HIGH TEMPS FRIDAY LOWER
30S NE TO UPEPR 30S SW.

SKIES WILL CLEAR OUT WEST-EAST FRIDAY NIGHT AS THE LOW PRESSURE
SYSTEM PULLS AWAY FROM THE NC COAST. NORTH-NWLY WINDS ON THE BACK
SIDE OF THE LOW WILL BEGIN TO ADVECT AN ARCTIC AIR MASS INTO CENTRAL
NC FRIDAY NIGHT. MIN TEMPS BY EARLY SATURDAY LOWER 20S NORTH AND MID
20S SOUTH.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 325 AM THURSDAY...

...BITTERLY COLD AIR THIS WEEKEND WITH A WINTRY WEATHER THREAT EARLY
NEXT WEEK...

SATURDAY THROUGH SUNDAY: ARCTIC HIGH PRESSURE WILL BUILD INTO THE
REGION ON SATURDAY AS THE DEPARTING SYSTEM LIFTS WELL OFF TO THE
NORTH AND EAST OF THE AREA... WHILE A MID/UPPER LOW OVER THE
NORTHEAST U.S. TO START THE PERIOD SHIFTS EASTWARD AND OFFSHORE BY
SATURDAY NIGHT. THIS SHOULD RESULT IN A DRY... BUT COLD WEEKEND
ACROSS CENTRAL NC... WITH BREEZY CONDITIONS EXPECTED ON SATURDAY.
THE SURFACE HIGH SHOULD SETTLE OVER THE REGION ON SUNDAY... AT LEAST
TAKING AWAY THE ADDED CHILLY BREEZE. WITH LOW LEVEL THICKNESS VALUES
EXPECTED TO BE WELL BELOW NORMAL FOR THIS WEEKEND (BOTTOMING OUT
NEAR 1230 METERS ON SUNDAY MORNING) THINK TEMPS WILL BE NEAR 20
DEGREES BELOW NORMAL. HIGHS ON SATURDAY MAY STRUGGLE TO REACH
FREEZING ACROSS THE NORTHERN HALF OF THE CWA... WITH HIGH TEMPS
SUNDAY GENERALLY FREEZING OR BELOW FOR MOST... IF NOT ALL... OF THE
CWA. EXPECT HIGH ON SATURDAY WILL RANGE FROM THE LOWER 30S NORTH TO
NEAR 40 ACROSS THE FAR SOUTH. HIGHS SUNDAY ARE EXPECTED TO RANGE
FROM THE UPPER 20S TO GENERALLY THE LOWER 30S. LOW SUNDAY MORNING
WITH SURFACE HIGH PRESSURE JUST TO THE NORTHWEST OF THE AREA ARE
EXPECTED TO RANGE FROM AROUND 10 TO 15 DEGREES.

SUNDAY NIGHT THROUGH WEDNESDAY: THE NEXT SYSTEM WITH A THREAT OF
WINTER WEATHER IS EXPECTED TO AFFECT THE AREA EARLY MONDAY INTO
TUESDAY. MEDIUM RANGE MODELS CONTINUE TO SHOW S/W ENERGY TRACKING
FROM THE PLAINS INTO THE EASTERN U.S EARLY NEXT WEEK... WHILE
AMPLIFYING. THIS SHOULD HELP A SURFACE LOW DEVELOP ACROSS THE
SOUTHEAST U.S... WITH PRECIP SPREADING INTO CENTRAL NC IN ADVANCE OF
THE APPROACHING SYSTEM ON SUNDAY NIGHT/MONDAY MORNING. MEANWHILE...
THE ARCTIC SURFACE HIGH (WHICH WILL BE OVERHEAD ON SUNDAY) WILL
SHIFT OFFSHORE SUNDAY NIGHT INTO MONDAY. HOWEVER... THERE SHOULD BE
AMPLE COLD DRY AIR IN PLACE TO SUPPORT EITHER SNOW OR SLEET EARLY
MONDAY MORNING... FOR LOCATIONS THAT DO INDEED SEE PRECIP (BEST
CHANCE ACROSS THE WESTERN/NORTHWESTERN PIEDMONT). HOWEVER... WE ARE
TALKING ABOUT S/W ENERGY THAT HAS NOT MOVED ONSHORE YET ACROSS THE
WESTERN U.S... WHICH HAS LED TIMING/TRACK/STRENGTH DIFFERENCES WITH
THIS SYSTEM FROM RUN TO RUN ALONG WITH A LARGE SPREAD IN THE MODELS
AND THE ENSEMBLES... THOUGH IT APPEARS WE SHOULD SEE SOME TYPE OF
DAMMING DEVELOP ON MONDAY (IN-SITU POSSIBLY). HOW AMPLIFIED THE
TROUGH IS AND THE TRACK AND CONFIGURATION OF THE SURFACE LOW/LOWS
WILL GREATLY AFFECT WHAT TYPE OF PRECIP WE SEE ON MONDAY INTO
TUESDAY (OUTSIDE OF THE INITIAL LEAD PRECIP WHICH WILL LIKELY BE IN
THE FORM OF SNOW OR SLEET). WILL CONTINUE TO TREND THE FORECAST TO
THE CLIMATOLOGICAL FAVORED AREAS FOR WINTER PRECIP... WITH MOST
LOCATIONS TURNING TO ALL RAIN BY MONDAY EVENING. GIVEN THE TIMING
ISSUES THERE IS SOME UNCERTAINTY WITH REGARD TO HOW FAST THE PRECIP
WILL EXIT... AND IF WE COULD SEE ANY WRAP AROUND WINTER PRECIP. FOR
NOW WILL CONTINUE TO SHOW TEMPS MODERATING ON TUESDAY... WITH ONLY
ONE P-TYPE... RAIN. DRY WEATHER IS EXPECTED TO RETURN ON TUESDAY
NIGHT AND CONTINUE FOR WEDNESDAY.

HIGH AND LOW TEMPS EARLY NEXT WEEK WILL GREATLY DEPEND ON THE TIMING
AND TRACK OF THE SYSTEM... THOUGH WE SHOULD SEE LOWS GENERALLY IN
THE 20S FOR MONDAY MORNING. TEMPS SHOULD MODERATE BACK TO NEAR
NORMAL BY MID NEXT WEEK... WITH HIGHS BACK INTO THE 50S... LOWS IN
THE 30S.

&&

.AVIATION /12Z THROUGH MONDAY/...
AS OF 640 AM THURSDAY...

HIGH CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL ACROSS CENTRAL NC
THROUGH TONIGHT. SFC WINDS WILL GENERALLY BE 10 KTS OR LESS EXPECT
IN THE VICINITY OF KRWI WHERE EARLY MORNING GUSTS 14-18KTS MAY OCCUR.

AN UPPER LEVEL DISTURBANCE WILL CROSS THE MID ATLANTIC FRIDAY. THIS
SYSTEM MAY BRING LOW END VFR/MVFR CEILINGS TO CENTRAL
NC...ESPECIALLY KRWI AND KFAY ALONG WITH A THREAT FOR LIGHT WINTRY
PRECIPITATION...MAINLY IN VICINITY OF KRDU...KRWI...AND KFAY. THE
WINTRY PRECIPITATION MAY CAUSE BRIEF INTERVALS OF MVFR CEILING AND
VISIBILITY.

ARCTIC AIR WILL SPILL INTO CENTRAL NC BEHIND THE DEPARTING DISTURBANCE
SATURDAY AND SUNDAY. BRISK NORTHERLY WINDS EXPECTED SATURDAY WITH
GUSTS 20-25KTS HIGHLY PROBABLE. THE NEXT THREAT FOR ADVERSE AVIATION
CONDITIONS SHOULD OCCUR MONDAY AS AN AREA OF LOW PRESSURE LIFTS
NORTHEASTWARD ACROSS THE SE U.S.

&&

.CLIMATE...

HERE ARE THE RECORD LOWS AND RECORD LOW MAXIMUM TEMPERATURES FOR SAT
FEB 13TH AND SUN FEB 14TH AT GSO... RDU... AND FAY:


       REC    YR     REC    YR
       LOW         LOW MAX
----------------------------------------------
GSO:
02/13   11   1955     31   1986
02/14    6   1905     22   1914

RDU:
02/13    4   1899     10   1899
02/14   -2   1899     27   1916

FAY:
02/13   14   1973     32   1955
02/14   12   1968     33   1916


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


&&

$$

SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
CLIMATE...WFO RAH



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