Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 181418
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1015 AM EDT SAT OCT 18 2014

.SYNOPSIS....A DRY COLD FRONT WILL EXIT CENTRAL NC EARLY THIS
AFTERNOON. A SECONDARY COLD FRONT ATTENDANT TO A POTENT BUT
MOISTURE-STARVED SHORTWAVE TROUGH ALOFT WILL CROSS THE REGION
THIS EVENING. HIGH PRESSURE WILL FOLLOW AND BUILD INTO THE REGION
FROM THE NORTHWEST SUNDAY.

&&

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

A S/W ROTATING ENE ACROSS SOUTHERN NEW ENGLAND WAS PROPELLING A COLD
FRONT ACROSS CENTRAL NC LATE THIS MORNING. THIS SFC FEATURE SHOULD
EXIT OUR REGION BY EARLY AFTERNOON. AIR MASS IS RATHER DRY AND
STABLE SO THE PASSAGE WILL NOT BE NOTED BY ANY WEATHER OR CLOUDS. NW
WINDS BEHIND THE FRONT WILL BECOME A LITTLE BREEZY THIS AFTERNOON
WITH GUSTS AROUND 20 MPH HIGHLY PROBABLE. THE NOTICEABLY COOLER AIR
WILL ARRIVE THIS EVENING WITH THE PASSAGE OF THE 700MB TROUGH.
FORECAST HIGH TEMPS LOWER 70S NW TO UPPER 70S SE APPEAR ON TARGET. -WSS


TONIGHT: A SECONDARY COLD FRONT...ONE ACCOMPANYING A POTENT
SHORTWAVE TROUGH FORECAST TO AMPLIFY FROM NW WISCONSIN THIS MORNING
TO NC/VA BY 06Z...WILL SWEEP SOUTHEAST ACROSS CENTRAL NC THIS
EVENING. THIS FRONT WILL ALSO BE A MOISTURE-STARVED ONE...WITH
SIMPLY A PERIOD OF PARTLY CLOUDY CONDITIONS...TO PERHAPS BRIEFLY
MOSTLY CLOUDY ONES MAINLY NEAR THE VA BORDER...AS THE MID LEVEL
TROUGH AND ASSOCIATED (RELATIVE) MOIST AXIS PIVOTS EAST. CAA-DRIVEN
LOWS IN THE 40S.  -MWS

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 340 AM SATURDAY...

BENEATH STRONG HEIGHT RISES ALOFT AND ASSOCIATED SUBSIDENCE...1020-
1025 MB SURFACE HIGH PRESSURE WILL BUILD EAST ACROSS THE TN VALLEY
AND CENTRAL APPALACHIANS...TO A POSITION DIRECTLY OVER EAST-CENTRAL
NC BY 12Z MON. DESPITE ABUNDANT SUNSHINE...TEMPERATURES WILL BE
NOTICEABLY COOLER...WITH HIGHS GENERALLY IN THE LOWER TO MIDDLE 60S
GIVEN PROJECTED 00Z LOW LEVEL THICKNESSES AROUND 1350 METERS.
SIMILAR THICKNESS VALUES AT 12Z MON WOULD SUPPORT WIDESPREAD 30S -
INCLUDING LOWER TO MIDDLE ONES IN THE TYPICALLY COOLER RURAL AREAS -
IF IDEAL RADIATION COOLING CONDITIONS WERE REALIZED. WHILE CALM WILL
PREVAIL UNDER THE INFLUENCE OF THE SURFACE RIDGE...THE APPROACH OF A
DEAMPLIFYING UPPER WAVE THAT WAS LOCATED OVER SW NEW MEXICO THIS
MORNING WILL RESULT IN INCREASING CIRRUS FROM THE WEST OVERNIGHT.
GIVEN THE EXPECTED INCREASING HIGH CLOUDS...EXPECT LOWS MOSTLY
BETWEEN 35 AND 40 DEGREES - COOLEST EAST AND NORTHEAST WHERE CLOUDS
WILL BE SLOWEST TO ARRIVE/WELL AFTER MIDNIGHT. PATCHY FROST WILL
BE POSSIBLE IN THE AFOREMENTIONED TYPICALLY COOLER AREAS.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 340 AM SATURDAY...

HIGH PRESSURE OVER THE REGION MONDAY MORNING WILL PUSH OFFSHORE
DURING THE DAY AND ALLOW SOME ADDITIONAL MODERATION OF TEMPS MONDAY
AND TUESDAY BEFORE A SHORTWAVE DIVES THROUGH THE MIDWEST AND CROSSES
CENTRAL NC TUESDAY EVENING.  DESPITE THE RETURN FLOW AHEAD OF THE
SHORTWAVE AND WARMING INTO THE UPPER 60S AND LOWER 70S...MOISTURE
WILL BE VERY LIMITED...CONFINED TO A SHALLOW LAYER AROUND 700MB.
MAY SEE A FEW SHOWERS WITH THE FRONT TUESDAY EVENING...ESPECIALLY
NEAR THE VA BORDER WHERE HEIGHT FALLS  AND DCVA ASSOCIATED WITH THE
TROUGH ALOFT WILL SLIGHTLY STRONGER.  WILL MAINTAIN THE SLIGHT
CHANCE FOR A FEW LIGHT SHOWERS TUESDAY AFTERNOON/EVENING.  BEHIND
THE FRONT...THE UPPER TROUGH IS FORECAST TO CONTINUE DEEPENING AND
EVENTUALLY CLOSE OFF NEAR THE MID-ATLANTIC COAST.  THE GFS AND ECMWF
BOTH SUGGEST THE POTENTIAL FOR SOME ADDITIONAL SHOWERS AS THE CORE
OF THE COLDER AIR ALOFT MOVES OVERHEAD WEDNESDAY...THOUGH CONFIDENCE
IN THIS IS PRETTY LOW GIVE THE LACK OF MOISTURE IN FORECAST
SOUNDING`S.  OTHERWISE...THE PATTERN SHOULD BE DRY FOR THE REMAINDER
OF THE REMAINDER OF THE WEEK AS THE UPPER LOW SLOWLY BEGINS TO DRIFT
OFFSHORE.  THICKNESSES ARE PROGGED TO FALL BACK INTO THE 1340-1345M
RANGE...WHICH IS ABOUT 10-15M BELOW NORMAL AND SUGGEST TEMPS IN THE
LOW/MID 60S MIDWEEK AND THEN REBOUNDING BACK TOWARD THE LOWER 70S.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 745 AM SATURDAY...

A PAIR OF DRY COLD FRONTS WILL CROSS CENTRAL NC DURING THE TAF
PERIOD - ONE THIS MORNING AND ANOTHER THIS EVENING. INITIALLY LIGHT
WSW SURFACE WINDS WILL VEER TO WNW AND INCREASE INTO THE 9-14 KT
RANGE WITH GUSTS OF 15-20 KTS...AS THE LEAD COLD FRONT CROSSES THE
AREA BETWEEN 14-17Z. A PERIOD OF BROKEN 3000-4000 FT CLOUDINESS MAY
SPILL EAST OF THE APPALACHIANS/INTO THE NW NC PIEDMONT (KINT/KGSO)
THIS EVENING...WITH FEW TO SCATTERED CLOUD BASES BETWEEN 4000-6000
FT...AND AT 25000 FT...ELSEWHERE AND OTHERWISE. WHILE SURFACE WINDS
WILL LESSEN AROUND SUNSET...THE PASSAGE OF THE SECONDARY COLD FRONT
WILL LIKELY CAUSE THEM TO PICK UP ONCE AGAIN...INTO THE 7-12 KT
RANGE WITH A FEW GUSTS MAINLY AT TRIAD TERMINALS...BETWEEN 00-06Z.

OUTLOOK: THE DEVELOPMENT OF AN UPPER LOW OVER THE MIDDLE ATLANTIC
STATES WILL RESULT IN A CHANCE OF SHOWERS TUE-WED.

&&

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

&&

$$

SYNOPSIS...WSS/MWS
NEAR TERM...WSS/MWS
SHORT TERM...MWS
LONG TERM...BLS
AVIATION...MWS



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