Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KRAH 261131
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
730 AM EDT SAT JUL 26 2014

.SYNOPSIS...A SURFACE TROUGH WILL DEVELOP OVER THE WESTERN PIEDMONT
THIS WEEKEND...RESULTING IN A VERY WARM SOUTHWEST FLOW. A STRONG
COLD FRONT WILL CROSS THE AREA ON MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 210 AM SATURDAY...

SHEARED S/W TROUGH AXIS WILL TRAVERSE THE AREA THIS MORNING...
RESULTING IN SCATTERED TO OCCASIONALLY BROKEN  MID AND HIGH CLOUDS.
SUBSIDENCE WILL FOLLOW IN ITS WAKE...COINCIDENT WITH PEAK AFTERNOON
HEATING...WHICH SHOULD LARGELY SUPPRESS CONVECTIVE RAIN CHANCES
TODAY AS FORCING WILL OTHERWISE BE CONFINED TO VERY SHALLOW
CONVERGENCE ASSOCIATED WITH THE DEVELOPING PIEDMONT SFC TROUGH.

LOW-LEVEL THICKNESSES ARE PROGGED TO REBOUND 20M FROM YESTERDAY AND
DESPITE SOME MORNING CLOUDS FROM BOTH S/W MOVING THROUGH THE AREA
ALONG WITH SLOW LIFTING/DISSIPATION OF MORNING STRATUS/FOG
ANTICIPATE WE SHOULD REACH FULL SUN READINGS. HIGHS IN THE UPPER
80S/NEAR 90 NORTH TO LOWER 90S SOUTH. LOWS TONIGHT UNDER CLEAR SKIES
IN THE LOWER TO MID 70S.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 320 AM SATURDAY...

SUNDAY AND SUNDAY NIGHT:
A STRONG UPPER TROUGH OVER THE UPPER MS VALLEY SUNDAY MORNING WILL
TRACK SOUTHEASTWARD INTO THE OH VALLEY SUNDAY/SUNDAY NIGHT.
ACCOMPANYING SURFACE FRONT WILL APPROACH THE SOUTHERN APPALACHIANS
LATE SUNDAY NIGHT/MONDAY MORNING. IN THE MEAN TIME...PIEDMONT TROUGH
BISECTING THE AREA WILL BEGIN TO SHARPEN UP.

IN ADVANCE OF THE MAIN SHORTWAVE...CONVECTION...POSSIBLY A MCS IS
EXPECTED TO BE ONGOING OVER THE CENTRAL AND POSSIBLY SOUTHERN
APPALACHIANS EARLY SUNDAY. SOME STORMS COULD PERSIST INTO THE
AFTERNOON AS THEY MOVE EASTWARD INTO THE VIRGINIA PIEDMONT AND
COASTAL PLAIN. IF THIS CONVECTIN DOES INDEED HOLD TOGETHER...OUTFLOW
FROM THESE STORMS COULD SUPPORT A SLIGHT TO SMALL CHANCE OF STORMS
MAINLY ACROSS THE NORTH/NORTHEAST SUNDAY AFTERNOON AS HINTED BY THE
LATEST EC AND SOME OF THE CONVECTION ALLOWING MODELS. IF STORMS
DO DEVELOP...A MODIFIED EML LAYER CHARACTERIZED BY LAPSE RATES OF
7.25-7.50 COULD SUPPORT ISOLATED SEVERE STORM THAT COULD
LARGE HAIL. WILL RETAIN SLIGHT TO SMALL CHANCE POPS SUNDAY NIGHT
WITH BEST CHANCE IN PROXIMITY TO SURFACE FRONT TO OUR NW.

DEEP MIXING AND 850MB TEMPS IN EXCESS OF 21C WILL LEAD TO HIGHS IN
THE MID AND UPPER 90S.  MIXING WILL DROP DEWPOINTS A
BIT...ESPECIALLY WEST OF THE PIEDMONT TROUGH...BUT TO THE EAST
DEWPOINTS ARE FORECAST TO REMAIN IN THE UPPER 60S TO AROUND 70.  THE
RESULTING HEAT INDEX VALUES ARE IN THE 100-103.  LOWS SUNDAY NIGHT
IN THE LOWER TO MID 70S.


MON/MON NIGHT: FOCUS ON MONDAY WILL BE THE LIKELIHOOD FOR SEVERE WEATHER AS A
STRONG COLD FRONT APPROACHES AND MOVES THROUGH THE AREA. THIS FRONT
WILL BE PROPELLED TOWARDS THE REGION AS A UNSEASONABLE STRONG UPPER
LEVEL TROUGH PUSHES EAST...WITH STRONG 40-60M HEIGHT FALLS EXPECTED
TO OVERSPREAD CENTRAL NC. THIS WILL COMBINE WITH THE EXPECTED STRONG
INSTABILITY (~1500-2000 J/KG MLCAPE) AND 40-50 KNOTS OF BULK SHEAR
TO PRODUCE SCATTERED SEVERE STORMS...WITH SUPERCELLS PROBABLE
CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. ALTHOUGH
CONFIDENCE IS HIGH THAT THERE WILL BE SEVERE WEATHER ON MONDAY...
THERE ARE STILL SOME UNCERTAINTIES. DEEP WESTERLY FLOW MAY LIMIT
MOISTURE AND ULTIMATE COVERAGE...HOWEVER ANY STORM THAT DOES FORM
WILL LIKELY BE INTENSE. IN ADDITION...OUTFLOW BOUNDARIES AND DEBRIS
CLOUDINESS FROM CONVECTION SUNDAY NIGHT WILL HAVE AN IMPACT ON
CONVECTIVE DEVELOPMENT/LOCATION. REGARDLESS...AT THIS TIME...THE
BEST CHANCE FOR FOR PRECIP AND ULTIMATE SEVERE STORMS LOOKS TO BE
ACROSS THE EASTERN HALF OF THE FORECAST AREA (ALONG AND EAST OF THE
EXPECTED LOCATION OF THE LEE/PREFRONTAL TROUGH) AND POSSIBLY MORESO
ALONG AND EAST OF THE I-95 CORRIDOR WHERE ALL THE PARAMETERS WILL
LINE UP THE BEST. HIGH TEMPS ARE EXPECTED TO CLIMB INTO THE LOW TO
MID 90S AHEAD OF THE FRONT...WITH OVERNIGHT LOWS GENERALLY IN THE
MID TO UPPER 60S.
&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...

UPPER LEVEL TROUGHING WILL STAY IN PLACE OVER THE EAST COAST
THROUGHOUT THE ENTIRE LONG TERM PERIOD PERIOD...WHILE AT THE SURFACE
COOL...CANADIAN HIGH PRESSURE WILL SETTLE OVER THE AREA. ALL OF THIS
WILL LEAD TO BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE
LOW/MID 80S AND OVERNIGHT LOWS IN THE LOW/MID 60S...POSSIBLY EVEN
SOME UPPER 50S IN THE NORMAL COOLER SPOTS. IN ADDITION... MOSTLY DRY
CONDITIONS ARE EXPECTED THROUGH THE END OF THE WEEK...ALTHOUGH WILL
SHOW A SLIGHT INCREASE IN PRECIP CHANCES BY FRIDAY AS MOISTURE
SLOWLY RETURNS.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 730 AM SATURDAY...

24-HR TAF PERIOD: RAP SOUNDINGS SUGGEST LIFR MORNING FOG/STRATUS
WILL LIFT AND DISPERSE TO MVFR AOA 14Z WITH VFR CONDITIONS RETURNING
BY 16Z. EXPECT MOSTLY DRY CONDITIONS TODAY WITH WINDS PREDOMINATELY
FROM THE SOUTHWEST AND LIGHT. THE PROBABILITY FOR FOG TONIGHT IS
LOW...LIKELY LIMITED FOG PRONE LOCATIONS SUCH AS KRWI.

LOOKING AHEAD: A COLD FRONT WILL APPROACH FROM THE NW SUNDAY/EARLY
NEXT WORK WEEK... BRINGING THE POTENTIAL FOR SHOWERS/STORMS AND SUB-
VFR CONDITIONS LATE SUNDAY (IN THE NORTHWEST) INTO MONDAY...
PARTICULARLY MONDAY (ESPECIALLY EAST). VFR CONDITIONS ARE EXPECTED
TO RETURN BEHIND THE FRONT ON TUESDAY AND CONTINUE THROUGH AT LEAST
MID WEEK.

&&

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

&&

$$

SYNOPSIS...WSS
NEAR TERM...CBL
SHORT TERM...CBL/KRD
LONG TERM...KRD
AVIATION...CBL



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.