-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 201714
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
115 PM EDT MON MAY 20 2013

.SYNOPSIS...
A WEAKENING MID AND UPPER LEVEL TROUGH WILL SETTLE OVER CENTRAL
NORTH CAROLINA TODAY BRINGING MORE UNSETTLED CONDITIONS WITH LOCALLY
HEAVY RAIN. THE TROUGH WILL GRADUALLY MOVE TO NEAR THE COAST ON
TUESDAY REDUCING THE THREAT OF LOCALLY HEAVY RAIN.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 930 AM MONDAY...

...LOCALLY HEAVY RAIN TODAY INTO THE EVENING...

AN UPPER LEVEL MESO-LOW AND ASSOCIATED 500 MB TROUGH WILL LINGER
OVER THE SOUTHEASTERN COASTAL STATES TODAY...WHILE AT THE
SURFACE...RETURN FLOW AROUND A HIGH OF THE MID-ATLANTIC COAST WILL
KEEP LIGHT GRADUAL UPSLOPE FLOW OVER CENTRAL NORTH CAROLINA. CURRENT
RUN OF THE NAM SHOWS GOOD MOISTURE TRANSPORT AND CONVERGENCE OVER
THE CENTRAL AND EASTERN PORTIONS OF THE STATE. CURRENT SPC
MESO-ANALYSIS SHOWS PW VALUES BETWEEN 1.6 AND 1.8 INCHES ACROSS THE
CWA. THIS PATTERN SHOULD HOLD FOR MUCH OF THE DAY AS CURRENT AXIS OF
PRECIPITATION OVER THE CENTRAL PORTION OF THE CWA GRADUALLY MOVES
EASTWARD INTO THE I-95 CORRIDOR. FURTHER TO THE WEST A SHORTWAVE
TROUGH IS EXPECTED TO SWING THROUGH THE WESTERN HALF OF THE STATE
PROVIDING A LITTLE MORE FORCING FOR AFTERNOON SHOWERS AND
THUNDERSTORMS. HRRR MODEL INDICATES THAT SOME HEAVIER SHOWERS WILL
DEVELOP AND MOVE INTO SOUTHWESTERN COUNTIES THIS AFTERNOON. MUCH OF
THE CENTRAL PORTION OF THE CWA HAS RECEIVED SIGNIFICANT RAINFALL
OVER THE PAST 24 HOURS BUT RAINFALL RATES HAVE BEEN LOW ENOUGH THAT
ANY FLOODING PROBLEMS HAVE BEEN NON-EXISTENT AT THIS TIME. WE WILL
CONTINUE TO MONITOR URBAN AREAS AND SMALL STREAMS FOR FLOODING
ACTIVITY WITH CONTINUED RAINFALL THIS AFTERNOON.

AT THIS HOUR MUCH OF THE AREA IS OVERCAST...BUT SOME BREAKS IN THE
CLOUDS COULD PROVIDE SOME DIFFERENTIAL HEATING BOUNDARIES THIS
AFTERNOON. WHILE SHOWERS AND THE OCCASIONAL THUNDERSTORM WILL BE
PROBABLE THIS AFTERNOON...THE LIKELIHOOD THAT ANY OF THESE STORMS
BECOMES SEVERE IS RELATIVELY LOW. WHILE THERE IS SOME
INSTABILITY...EFFECTIVE SHEAR IS VIRTUALLY NON-EXISTENT AND LAPSE
RATES ARE MODEST AT BEST. NO DCAPE TO WORK WITH MAKES SEVERE WINDS
VERY UNLIKELY. EXPECT LOWER CEILINGS TO CONTINUE TO PREVAIL THROUGH
THE MORNING AND INTO THE AFTERNOON ALSO HINDERING INSTABILITY.
DESPITE THIS...HIGHS SHOULD STILL REACH NEAR THE 80 DEGREE MARK THIS
AFTERNOON AS SOUTHWESTERLY FLOW AND WARM AIR ADVECTION HELP ELEVATE
HIGHS TODAY. -ELLIS

SHOWERS AND SCATTERED THUNDERSTORMS SHOULD DIMINISH WITH LOSS OF
HEATING THIS EVENING. WITH THE BASE OF THE TROUGH STILL OVER THE
REGION... WE WILL CONTINUE TO CARRY LOW END POPS AND QPF UNDER 0.25.
LOWS 65-70. STRATUS AND FOG WILL AGAIN BE PROBLEMATIC ESPECIALLY
09Z-13Z/TUE. -BADGETT

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...

A CONTINUED WEAKENING TREND WITH THE TROUGH AND A GRADUAL SHIFT
EASTWARD WILL MEAN MORE SCATTERED AND LESS CONCENTRATED CONVECTIVE
RAINFALL ON TUESDAY AFTERNOON AND EVENING. SEVERAL MODEL SOLUTIONS
INDICATE THE SUBTROPICAL RIDGE EXTENDING WESTWARD FROM THE WESTERN
ATLANTIC OVER PORTIONS OF NC. AFTER A START TO THE DAY WITH LOW
STRATUS AND AREAS OF FOG... PARTLY SUNNY SKIES ARE EXPECTED. HIGHS
SHOULD REBOUND INTO THE LOWER TO MID 80S. HOWEVER... DEW POINTS WILL
STILL BE IN THE MID TO UPPER 60S. THE COOLER MET/NAM GUIDANCE LOOKS
MORE IN LINE WITH THE CURRENT EXPECTATIONS WITH THE SSW FLOW AND
PLENTY OF LOW LEVEL MOISTURE AND BROKEN AFTERNOON CLOUDINESS. WIDELY
SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED. THIS
ACTIVITY WILL DIMINISH TUESDAY EVENING WITH LOSS OF HEATING. PARTLY
CLOUDY SKIES WITH AREAS OF FOG AGAIN EXPECTED LATE AT NIGHT. LOWS IN
THE MID 60S.

&&


.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...

UPPER LEVEL RIDGE BUILDS BRIEFLY OVER THE AREA ON WEDNESDAY... WHICH
SHOULD DIMINISH THE COVERAGE OF CONVECTION... ALTHOUGH DIURNALLY
DRIVEN THUNDERSTORMS CONTINUE TO BE POSSIBLE WITH THE MOIST AIRMASS
OVER THE AREA. PWATS WILL REMAIN NEAR 1.5... 2 STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. WITH WEAK SHEAR... EXPECTING
PULSE TYPE STORMS. HIGHS IN THE MID 80S... LOWS MID 60S.

UPPER LEVEL RIDGE SHIFTS OFFSHORE THURSDAY. AFTERNOON THUNDERSTORMS
CONTINUE TO BE POSSIBLE IN THE AFTERNOON THURSDAY AS PWATS REMAIN
ABOVE NORMAL. BULK SHEAR INCREASES TO 25 TO 30 KTS... WHICH MAY
SUPPORT SOME MULTICELL ORGANIZATION. THICKNESSES REMAIN NEAR TO
SLIGHTLY ABOVE AVERAGE THURSDAY AND FRIDAY... FAVORING TEMPERATURES
CONTINUING TO A BE A FEW DEGREES ABOVE NORMAL... WITH HIGHS IN THE
80S AND LOWS IN THE UPPER 60S. THE TROUGH OVER THE MIDWEST MOVES
EASTWARD ON THURSDAY... AND THE ATTENDANT COLD FRONT PUSHES ACROSS
THE REGION FRIDAY. TIMING HAS TRENDED FASTER DURING TODAYS MODEL
RUNS... WITH THE FRONT MAKING IT THROUGH THE AREA EARLY FRIDAY...
AND TO THE CAROLINA COAST FRIDAY MORNING. STRONGEST DYNAMIC FORCING
REMAINS NORTH OVER NEW ENGLAND... AND WITH THE TIMING NOW LOOKING
MORE DIURNALLY UNFAVORABLE... DO NOT EXPECT A THREAT OF SEVERE
WEATHER.


&&

.AVIATION /18Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 115 PM MONDAY...

24 HOUR TAF PERIOD:

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL PREVAIL THIS
AFTERNOON ACROSS THE CWA AT ALL TERMINALS. CURRENTLY RADAR SHOWS
SHORTWAVE CURRENTLY MOVING ACROSS THE TRIAD WITH STRONGER CELLS ON
THE EASTERN SIDE WITH LINGERING SHOWERS TO THE WEST. FOR THE TRIAD
STRONGEST SHOWERS AND THUNDERSTORMS MOST LIKELY MOVING THROUGH NOW
THROUGH THE NEXT COUPLE OF HOURS AND DOWN TRENDING TO MOSTLY LIGHT
SHOWERS THEREAFTER. FURTHER TO THE EAST CONDITIONS SHOULD REMAIN
MORE FAVORABLE FOR HEAVIER SHOWERS AND THUNDERSTORMS THROUGH EARLY
EVENING. EXPECT CEILINGS TO BOUNCE BETWEEN VFR AND MVFR AND SINKING
OCCASIONALLY TO IFR IN THE STRONGER CELLS. WILL COVER THIS WITH A
TEMPO GROUP IN THE TAFS WITH VFR/MVFR PREVAILING. WINDS WILL REMAIN
GENERALLY SOUTHWESTERLY AT 5-10 KNOTS WITH OCCASIONAL GUSTS OF 15-20
IN HEAVY SHOWERS.

AFTER PRECIPITATION WINDS DOWN TONIGHT EXPECT SOME LOW
CEILINGS/VISIBILITIES...GENERALLY AFTER 3Z. EXPECT SOME FOG IN THE
WEST WITH MORE OF A LOW STRATUS SITUATION FURTHER TO THE EAST.
CONDITIONS SHOULD REMAIN SUB VFR EVERYWHERE UNTIL 15Z WHEN VFR
CEILINGS AND VISIBILITIES SHOULD RETURN. ALTHOUGH CONDITIONS WILL BE
IMPROVING AND GENERALLY DRYING...THE MESO-LOW WILL LINGER OVERHEAD
KEEPING THE CHANCE FOR SHOWERS ALIVE THROUGH THE END OF THE TAF
PERIOD.

LONG TERM:

LOW STRATUS AND FOG ARE EXPECTED TO RETURN TUESDAY NIGHT INTO
WEDNESDAY. WEDNESDAY WILL BE THE DRIEST DAY BUT WILL STILL HAVE THE
CHANCE FOR DIURNAL SHOWERS AND STORMS. THURSDAY AND THURSDAY NIGHT
WILL FEATURE THE PASSAGE OF A COLD FRONT AND A RETURN TO SUB-VFR
CONDITIONS. VFR CONDITIONS WILL GRADUALLY RETURN TO THE AREA ON
FRIDAY.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...ELLIS/BADGETT
SHORT TERM...BADGETT
LONG TERM...SEC
AVIATION...ELLIS