Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 262321
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
620 PM EST FRI DEC 26 2014

.SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE CAROLINAS THROUGH
SATURDAY...THEN SHIFT OFFSHORE SATURDAY NIGHT. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST ON SUNDAY AND GRADUALLY MOVE SOUTHWARD
THROUGH THE REGION ON MONDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 300 PM FRIDAY...

LATEST SURFACE AND UPPER AIR ANALYSES SHOWS HIGH PRESSURE DOMINATING
CENTRAL NC...RESULTING IN CONTINUED TRANQUIL WEATHER. THE SURFACE
HIGH WILL REMAIN OVERHEAD TONIGHT...LEADING TO ANOTHER GREAT
RADIATIONAL COOLING SETUP AS SKIES STAY CLEAR AND WINDS BECOME
NEARLY CALM. MOSTLY LOWER 30S ARE EXPECTED (WITH MAYBE A FEW UPPER
20S IN THE NORMALLY COOLER LOCALES).

THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST.


&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...

SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.

SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.

SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 PM FRIDAY...

MONDAY THROUGH FRIDAY... PERTURBATION ALOFT AND ASSOCIATED SURFACE
WAVE AND FRONT WILL CROSS CENTRAL NC MONDAY MORNING. W-NW FLOW
BEHIND THE EXITING WEATHER SYSTEM MONDAY AFTERNOON-NIGHT WILL LEAD
TO DRIER AND MORE STABLE CONDITIONS. BASED ON CURRENT MODEL
TIMING...FAVOR HIGHEST POPS MONDAY MORNING WITH DECREASING POPS
MONDAY AFTERNOON AND LESS THAN 20 PERCENT POPS BY MONDAY NIGHT.
TEMPS MONDAY DEPENDENT UPON EVENTUAL TRACK OF THE SURFACE LOW. SOME
MODELS FAVOR A TRACK CLOSER TO THE NW PIEDMONT...PLACING BULK OF CWA
IN THE WARM SECTOR. OTHER MODELS CLUSTER AROUND A SOLUTION WITH THE
SFC WAVE CROSSING SC THEN UP ALONG THE NC COAST...PLACING CENTRAL NC
IN THE COOL SECTOR. THE LATER SOLUTION SEEMS MORE LIKELY CONSIDERING
THE POTENTIAL FOR A SHALLOW LAYER OF COOL AIR TO ADVECT INTO THE
REGION BEHIND THE INITIAL PERTURBATION. HAVE TRENDED MAX TEMPS A
LITTLE COOLER THAN MOS GUIDANCE BUT LATER FORECASTS MAY NEED TO
TREND COOLER.

TUESDAY THROUGH FRIDAY WILL FEATURE MAINLY DRY WEATHER WITH A
COOLING TREND AS BROAD UPPER LEVEL TROUGH COVERS THE U.S. THE WLY
FLOW ALOFT AND SFC HIGH PRESSURE DIVING SOUTHWARD ACROSS THE CENTRAL
U.S. NORMALLY SIGNALS DRY AND SEASONABLY COOL CONDITIONS FOR OUR
REGION. MAX TEMPS BY THE NEW YEAR WILL AVERAGE IN THE 40S TO NEAR 50
WITH MIN TEMPS IN THE 20S TO AROUND 30.

&&

.AVIATION /00Z SATURDAY THROUGH TUESDAY/...
AS OF 620 PM FRIDAY...

24-HOUR TAF PERIOD: HIGH CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL
THROUGH THE CURRENT TAF PERIOD. WINDS SHOULD BE CALM TO LIGHT AND
VARIABLE OVERNIGHT AS HIGH PRESSURE BUILDS OVERHEAD. SKIES WILL BE
CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH HIGH CLOUDS BUILDING IN
SATURDAY MORNING...BECOMING SCATTERED TO BROKEN. WINDS WILL BE
LIGHT AND GENERALLY SOUTHWESTERLY ON SATURDAY. -KC

LOOKING AHEAD: EXPECT AN INCREASING POTENTIAL FOR MVFR/IFR CEILINGS
AND RAIN LATE SATURDAY NIGHT THROUGH MONDAY AS A SLOW MOVING FRONT
PROGRESSES ACROSS THE REGION. CONDITIONS ARE EXPECTED TO IMPROVE BY
LATE MONDAY NIGHT INTO TUESDAY. -KRD

&&

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

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...KRD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...KC/KRD


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