-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 180157
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
957 PM EDT MON JUN 17 2013

.SYNOPSIS...
A WEAK FRONTAL BOUNDARY REMAINS TO THE NORTH OF THE REGION
TONIGHT. THIS FRONT WILL MOVE SOUTHWARD THROUGH THE LOCAL AREA ON
TUESDAY...THEN WASHES OUT OVER THE CAROLINAS ON WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
WILL MAINTAIN ISO-SCT SHWRS ERLY TNGT WITH DECENT LO-LVL MOISTURE
ALBEIT WEAK FORCING. MOST PRECIP WILL STAY SOUTH OF THE FA TNGT
WHERE DEEP-LAYER MOISTURE IS HIGHER. OTW...EXPECT PRTLY CLDY SKIES
ON AVG WITH SOME DRYING IN MID LVLS. MILD TEMPS WITH LGT SOUTHERLY
FLOW...LOWS IN THE UPR 60S TO LWR 70S.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
UPPER LOW WILL CONTINUE TO DIG OVER ERN CANADA TONIGHT/TUES
MORNING...DEEPENING THE UPPER TROUGH OVER THE ERN CONUS. A MORE
POTENT SHORTWAVE (CURRENTLY OVER S CNTRL CANADA) WILL DIVE DOWN
THE BACKSIDE OF THE UPPER TROUGH...LOCATING OVER THE GREAT LAKES
REGION TUES AFTERNOON. ANOTHER SHORTWAVE WILL TRAVERSE THE TN
VALLEY...LIFTING OVER THE MID ATLANTIC LATE TUESDAY. THE
AMPLIFYING UPPER PATTERN WILL RESULT IN INCREASING SWLY FLOW (H85
WINDS INCREASING TO 20-30 KT) AND GOOD MOISTURE TRANSPORT INTO THE
REGION (ESPECIALLY SE VA/NE NC) TUES-WEDS. PRECIP WATER VALUES
PROGGED TO APPROACH 2 INCHES (NEARLY +2 STD DEV) BY TUES
AFTERNOON. MEANWHILE...HEIGHT FALLS WILL RESULT IN THE DEVELOPMENT
OF A SFC LOW OVER THE LOWER MS VALLEY TONIGHT. SFC LOW WILL
PROGRESS EWD TUESDAY...REACHING NRN NC LATE IN THE DAY TUESDAY.
AFOREMENTIONED SHORTWAVE AND DIVERGENCE ALOFT (THANKS TO RRQ OF
DEPARTING 100+ KT UPPER JET) WILL PROVIDE FORCING FOR ASCENT OVER
THE REGION IN ADVANCE OF THE APPROACHING SFC LOW. EXPECT SHOWERS
TO LIFT INTO THE REGION BEGINNING TUES MORNING...AND SPREADING EWD
DURING THE AFTERNOON. THETA-E ADVECTION AND TEMPS IN THE LOW/MID
80S AND DEWPOINTS IN THE UPPER 60S/LOW 70S WILL MAINTAIN A
MARGINALLY UNSTABLE AIRMASS FOR AFTERNOON AND EVENING
THUNDERSTORMS...ESPECIALLY OVER ERN VA/SERN VA/NE NC. STEEP LOW
LEVEL LAPSE RATES AS WELL AS DECENT MID LEVEL LAPSE RATES MAY
RESULT IN STRONG WINDS UNDER THE STRONGEST STORMS. HOWEVER...SHEAR
WILL REMAIN RATHER WEAK...SO ORGANIZED STRONG THUNDERSTORMS ARE
NOT ANTICIPATED. ABUNDANT MOISTURE AND DEEP LIFT WILL RESULT IN
THE POTENTIAL FOR HEAVY RAINFALL.

AS THE LOW CROSSES NRN NC TUESDAY NIGHT...THE FIRST SHORTWAVE
WILL LIFT OFF THE VA COAST AS THE SECOND SHORTWAVE CROSSES THE OH
VALLEY. HEIGHT FALLS AND FRONTOGENETIC FORCING AROUND THE NRN
PERIPHERY OF THE SFC LOW MAY ENHANCE RAINFALL OVER SRN VA TUES
NIGHT. HAVE OPTED TO INCREASE POPS TO LIKELY ACROSS THAT REGION.
SFC COLD FRONT WILL CROSS THE REGION EARLY WEDS MORNING...SETTLING
OVER THE CAROLINAS WED. WILL MAINTAIN HIGH CHANCE POPS OVER SRN
VA/NRN NC THROUGH EARLY WEDS AFTERNOON. THEREAFTER...HIGH PRESSURE
WILL USHER IN BEHIND THE DEPARTING LOW/SFC FRONT...SHUNTING THE
BEST MOISTURE OFFSHORE BY WEDS NIGHT. WILL KEEP LOW END CHANCE
POPS FOR SCATTERED SHOWERS WEDS AFTERNOON AS THE TROUGH REMAINS
ALONG THE COAST. DRY THURS AS HIGH PRESSURE BUILDS NORTH OF THE
REGION AND MOISTURE SOURCE PUSHES WELL OFFSHORE.

SLIGHTLY BELOW NORMAL TUESDAY (LOW/MID 80S) WILL COOL TO NEARLY
-1 STD DEV WED AND THURS (LOW 80S). LOWS WILL FALL INTO THE LOW
60S...POSSIBLY UPPER 50S SOME LOCALES BY THURS MORNING.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A RATHER BENIGN PATTERN IS EXPECTED LATE THIS WEEK THROUGH THE
WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE SLOWLY DROPS S OFF THE
MID-ATLANTIC COAST. THERE IS VERY LITTLE POTENTIAL FOR
SHOWER/THUNDERSTORM DEVELOPMENT DUE TO A LACK OF LARGE SCALE FORCING
AND ANY SURFACE FOCUSING MECHANISMS. A GENERAL SHIFT OF THE
LOW-LEVEL FLOW FROM SE-SW WILL PRODUCE A STEADY WARMING TRENDS WITH
HIGHS RISING FROM THE LOW TO MID 80S FRIDAY...TO THE UPPER 80S TO
LOW 90S BY MONDAY. LOW TEMPERATURES SHOULD TREND UPWARD FROM 60-65
EARLY IN THE PERIOD TO THE UPPER 60S/LOW 70S LATE IN THE PERIOD.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
MOSTLY VFR CONDS EARLY TONIGHT WITH SOME SCATTERED SHOWERS/TSTMS
OVER THE PIEDMONT AND SOUTHSIDE VA. SOME OF THIS ACTIVITY MAY
LINGER INTO LATE TONIGHT BEFORE DYING...HOWEVER ONLY A SMALL
CHANCE THAT TERMINALS MAY BE AFFECTED. GUIDANCE DOES SUGGEST THAT
SOME ACTIVITY MAY DEVELOP NEAR ORF AROUND MIDNIGHT.
OTHERWISE...PARTIAL CLEARING LATE TONIGHT AND LOW LEVEL MOISTURE
MAY PRODUCE SOME FOG AND STRATUS DURING THE OVERNIGHT AND EARLY
TUE MORNING. BRIEF MVFR/IFR CONDS ARE LIKELY BEFORE FOG BURNS OFF
SHORTLY AFTER DAYBREAK. MVFR CLOUDS MAY LINGER THRU THE MORNING
PERIOD BEFORE BREAKING BY MID DAY.

CONDITIONS REMAIN UNSETTLED ON TUE AS A MORE ORGANIZED AREA OF LOW
PRESSURE APPROACHES THE MID ATLANTIC REGION. THERE ARE SOME TIMING
DIFFERENCES AS TO WHEN THE LOW CROSSES THE AREA...HOWEVER ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS SHOULD BE ANTICIPATED DURING THE
AFTN AND EVENING HOURS. ONCE AGAIN...A BRIEF REDUCTION TO CIGS/VIS
SHOULD BE EXPECTED UNDER STRONGER STORM CORES.

&&

.MARINE...
A DISSIPATING BOUNDARY IS PRESENTLY DROPPING ACROSS SE VA/NE NC THIS
AFTERNOON. ANY WIND SHIFT IS VERY LOCALIZED AT THIS TIME...WITH SW
FLOW RECOVERING N OF THE BOUNDARY...WHICH SHOULD CONTINUE OVERNIGHT
ACROSS THE MARINE AREA. A COLD FRONT IS SITUATED FROM THE EASTERN
GREAT LAKES THROUGH NEW ENGLAND AND THIS IS EXPECTED TO MOVE SOUTH
INTO PA TONIGHT AS LOW PRESSURE LIFTS ENE INTO THE TENNESSEE VALLEY.
NUMERICAL MODEL SOLUTIONS DIVERGE THROUGH THE DAY TUESDAY AS THE
19/12Z GFS LIFTS THE LOW ENE INTO W-CENTRAL NC WHILE THE 19/12Z NAM
LAGS THE LOW BACK OVER TN AT 00Z WEDNESDAY. THE 19/12Z ECMWF HAS
COME MORE INTO LINE WITH THE GFS IN TRACKING THE LOW ACROSS NC
TUESDAY NIGHT AND OFF THE COAST WEDNESDAY MORNING. IF THIS TIMING
VERIFIES THE WIND WOULD LIKELY SHIFT TO NNE FROM N-S LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING AND REMAIN NNE/NE THROUGH THURSDAY HIGH
PRESSURE BUILDS OVER NEW ENGLAND AND LOW PRESSURE LINGERS OFF THE
COAST. SCA WIND SPEEDS ARE POSSIBLE FOR THE BAY/SOUND/RIVERS LATE
TUESDAY NIGHT INTO WEDNESDAY WHILE ONSHORE FLOW HAS THE POTENTIAL TO
BUILD SEAS TO 5 FT WEDNESDAY INTO WEDNESDAY NIGHT. NO SCA FLAGS AT
THIS POINT GIVEN THE UNCERTAINTY AND THAT THE EARLIEST COMMENCEMENT
OF SCA CONDITIONS WOULD LIKELY BE LATE 3RD PERIOD INTO 4TH PERIOD.
THE HIGH SLOWLY SINKS S OFF THE COAST LATE IN THE WEEK INTO NEXT
WEEKEND WITH THE WIND VEERING FROM NE-S AND REMAINING AOB 15KT.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...JDM/SAM
NEAR TERM...MAS
SHORT TERM...SAM
LONG TERM...AJZ
AVIATION...BMD/JEF
MARINE...AJZ