-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 151904
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
305 PM EDT SAT JUN 15 2013

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH TONIGHT... THEN
MOVE OFF THE SOUTHEAST COAST SUNDAY. SOUTHERLY FLOW BEHIND THIS HIGH
WILL BRING INCREASING MOISTURE INTO THE AREA... AHEAD OF A COLD
FRONT THAT WILL MOVE IN FROM THE WEST ON TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...

FORECAST IS IN GOOD SHAPE. LATEST SURFACE ANALYSIS SHOWS THE HIGH
PRESSURE AREA CENTERED JUST TO OUR NORTHWEST... SPREADING TO THE
ESE. LOOKING ALOFT... THE DEW POINT DEPRESSION ON THE 850 MB
ANALYSIS REMAINS UNDER 8 DEGREES C AROUND THE REGION... TOPPED OFF
BY DRY AND WARM AIR AT 700 MB WITH MORE WARMING ADVECTING IN FROM
THE WEST. STILL EXPECT WE`LL SEE SCATTERED FLAT CUMULUS FORMING
BENEATH THE SUBSIDENCE INVERSION ALOFT WITH FURTHER HEATING THIS
AFTERNOON. HIGH LEVEL MOISTURE NOTED UPSTREAM OVER THE OHIO VALLEY
(BLOWN OFF FROM MCS ACTIVITY) IS POISED TO EXPAND SOUTHEAST INTO NC
THROUGH THE DAY BASED ON UPPER LEVEL FLOW ON THE BACK SIDE OF THE
DEPARTING FULL-LATITUDE LONGWAVE TROUGH SITUATED JUST OFF THE EAST
COAST... SO WE SHOULD SEE INCREASING HIGH THIN CLOUDS AS THE DAY
WEARS ON. TEMPS ARE RUNNING A FEW DEGREES ABOVE YESTERDAY`S PACE...
AND DESPITE SLIGHTLY BELOW NORMAL THICKNESSES THIS MORNING...
THICKNESSES ARE EXPECTED TO RISE AROUND 20 METERS TODAY. BASED ON
THIS AND THE FACT THAT TEMPS ARE ALREADY IN THE UPPER 70S TO AROUND
80 IN SPOTS... HAVE NUDGED UP HIGHS TO 84-89. -GIH

NAM AND GFS BUFR SOUNDINGS SHOW A RELATIVELY DRY AND CAPPED AIR MASS
PERSISTS OVERNIGHT. AS THE SURFACE HIGH QUICKLY MOVES SOUTHEAST...THE
NAM AND GFS BOTH INCREASE WINDS JUST OFF OF THE SURFACE APPRECIABLY
COMPARED TO CURRENT CONDITIONS. THIS SHOULD RESULT IN MORE MIXING
OVERNIGHT AND A MORE NOTICEABLE SOUTH OR SOUTHWEST BREEZE CERTAINLY
COMPARED TO THE CALM CONDITIONS OF EARLY THIS MORNING...ALTHOUGH NOT
SURE ABOUT THE WINDS BEING QUITE AS HIGH AS THE 10KT THE MOS
GUIDANCE SUGGESTS LATE TONIGHT. STILL...WITH A SOUTHWEST FLOW AND A
LITTLE MORE MIXING...EXPECT WARMER OVERNIGHT LOWS...60 TO 65
DEGREES. -DJF

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
AS OF 305 PM SATURDAY...

A BROAD UPPER TROUGH OVER THE EASTERN TWO-THIRDS OF THE NATION WILL
GRADUALLY AMPLIFY THIS PERIOD AS AN UPPER RIDGE BUILDS OVER THE
SOUTHERN PLAINS INTO THE ROCKIES. A SERIES OF S/WS IN THE DEVELOPING
W-NW FLOW ALOFT WILL BRING A THREAT FOR SHOWERS AND T-STORMS TO THE
REGION MON INTO TUESDAY...AND POSSIBLY BY THE TAIL END OF THE WORK
WEEK. THE MAIN WEATHER HEADLINE FOR NEXT WEEK STILL LOOKS TO BE THE
GOOD PROBABILITY OF MAX TEMPS 4-7 DEGREES BELOW NORMAL FOR THE THIRD
WEEK IN JUNE. THE UPPER LEVEL JET FORECAST TO BE FARTHER SOUTH THAN
NORMAL FOR THIS TIME OF YEAR. THIS SWD POSITION WILL ALLOW COOLER
CANADIAN AIR TO SPILL INTO THE NORTHERN THIRD OF THE U.S. WITH SOME
RESIDUAL AFFECTS BEING FELT IN THE CAROLINAS.

SUNDAY NIGHT INTO EARLY MONDAY...THE AIR MASS OVER CENTRAL NC WILL
BECOME RATHER MOIST AS SW FLOW THROUGH THE LOWEST 10K FT ADVECT
MOISTURE CURRENTLY RESIDING OVER THE NORTHWEST GULF. MEANWHILE A
LINE OF CONVECTION ASSOCIATED WITH A SWD DRIFTING SURFACE BOUNDARY
WILL LIKELY CROSS NORTHERN VA LATE SUN. THIS LINE OF CONVECTION MAY
SEND AN OUTFLOW INTO NORTHERN NC SUNDAY SUNDAY EVENING. IF THIS
OCCURS...AVAILABLE MOISTURE AND LOW LEVEL INSTABILITY WOULD SUSTAIN
ISOLATED TO SCATTERED CONVECTION ACROSS OUR FAR NORTHERN COUNTIES
INTO THE NIGHT. PLAN TO MAINTAIN SLIGHT CHANCE POP FOR NOW. EXPECT
WARMER MIN TEMPS DUE TO MORE CLOUDS AND A LIGHT SLY WIND. MIN TEMPS
IN THE UPPER 60S TO NEAR 70.

RESIDUAL OUTFLOW BOUNDARIES AND THE APPROACH OF A MID LEVEL TROUGH
INTERACTING WITH A MOISTURE-LADEN AIR MASS WILL TRIGGER SCATTERED
CONVECTION...ESPECIALLY IN THE AFTERNOON AND EVENING HOURS. WHILE
INSTABILITY PARAMETERS SUPPORTIVE OF A FEW STRONG STORMS...BULK
SHEAR VALUES OF 20KTS OR LESS FAVOR MULTI-CELLULAR/PULSE TYPE
CONVECTION.

MONDAY NIGHT THROUGH TUESDAY NIGHT...PRESENCE OF A MID LEVEL TROUGH
TRUDGING SLOWLY EAST ACROSS THE REGION COUPLED WITH THE MOIST AIR
MASS AND ADEQUATE INSTABILITY WILL SUPPORT THE CONTINUED DEVELOPMENT
OF SCATTERED TO NUMEROUS SHOWERS AND T-STORMS MONDAY NIGHT AND MORE
SO TUESDAY. AN INCREASING MID LEVEL WIND FIELD WILL INCREASE THE
BULK SHEAR TO 30-35KTS ACROSS THE NORTHERN COUNTIES TUESDAY
AFTERNOON. THIS ADDED ENERGY MAY CAUSE CONVECTION TO FORM INTO
BROKEN LINE SEGMENTS LATE IN THE DAY. SINCE AIR MASS WILL BE VERY
MOIST (LITTLE OPPORTUNITY FOR DRY AIR ENTRAINMENT)...SEVERE
POTENTIAL LOOKS LIMITED THOUGH WILL NEED TO MONITOR ELEVATED CORES
FOR WET MICROBURST POTENTIAL.  AS MID LEVEL TROUGH AND ASSOCIATED
SURFACE BOUNDARY DRIFT SWD TUESDAY NIGHT...EXPECT CONVECTION TO
DIMINISH FROM THE NORTH.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 305 PM SATURDAY...

WEDNESDAY THROUGH THURSDAY SHOULD SEE A RELATIVELY TRANQUIL WEATHER
PATTERN AS HIGH PRESSURE OVER THE LOWER GREAT LAKES NOSES SEWD INTO
OUR REGION. DEVELOPING ELY FLOW BY THURSDAY MAY ADVECT ATLANTIC
MOISTURE INTO CENTRAL NC RESULTING IN PERIODS OF CLOUDINESS. ANY
CONVECTION THAT OCCURS SHOULD BE LIMITED TO THE FAR SOUTHERN AND
WESTERN SECTIONS OF TH FORECAST AREA WHERE BETTER MOISTURE WILL
RESIDE. CONSIDERABLE CLOUDINESS.

MODEST MID-UPPER LEVEL RIDGING MAY OCCUR ACROSS THE SE U.S. FRI INTO
SATURDAY AHEAD OF THE NEXT S/W. THIS PATTERN WILL SUPPORT MORE OF A
SUMMERLIKE PATTERN WITH WARM AND SLIGHTLY HUMID CONDITIONS BY THE
END OF THE WEEK.

TEMPERATURE WISE....TEMPS MONDAY SHOULD BE FAIRLY CLOSE TO NORMAL
WITH MAX TEMPS IN THE MID-UPPER 80S. MAX TEMPS TUESDAY-THURSDAY WILL
LIKELY AVERAGE 4-5 DEGREES BELOW NORMAL...MAINLY DUE TO WIDESPREAD
SHOWERS TUESDAY AND LOW LEVEL N-NE FLOW ADVECTING COOLER AIR INTO
THE REGION WED-THU. MODIFYING AIR MASS WILL SEND TEMPS TO NEAR
NORMAL LEVELS BY SATURDAY.
-- End Changed Discussion --

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 150 PM SATURDAY...

HIGH CONFIDENCE OF VFR CONDITIONS THROUGH 18Z SUNDAY. SURFACE HIGH
PRESSURE AND WARM AND STABLE AIR ALOFT WILL RESULT IN MINIMAL CLOUD
COVER DURING THIS PERIOD... WITH ANY CLOUDS BASED ABOVE 5KFT AGL.
RELATIVELY LOW HUMIDITIES NEAR THE GROUND WILL LIMIT ANY FOG
DEVELOPMENT TONIGHT... RESULTING IN CONTINUED VFR VSBYS.

LOOKING BEYOND 18Z SUNDAY... CLOUDS WILL INCREASE SUNDAY AFTERNOON
AND NIGHT... AHEAD OF A COLD FRONT SLOWLY APPROACHING FROM THE
WEST... BUT CIGS SHOULD REMAIN VFR THROUGH SUNDAY NIGHT. BUT
INCREASING LOW LEVEL MOISTURE WILL BRING A RISK OF MVFR OR IFR FOG
LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. MVFR/IFR CONDITIONS AND
SHOWERS/STORMS ARE EXPECTED AS THE FRONT GETS CLOSER MONDAY
AFTERNOON THROUGH TUESDAY. VFR CONDITIONS ARE EXPECTED TO RETURN
BEHIND THE FRONT LATE TUESDAY NIGHT AND DOMINATE THROUGH THURSDAY...
ALTHOUGH BRIEF SUB-VFR CONDITIONS ARE POSSIBLE EARLY THURSDAY
MORNING. -GIH

&&

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

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/DJF
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...HARTFIELD