000
FXUS61 KAKQ 182004
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
404 PM EDT TUE JUN 18 2013
.SYNOPSIS...
WEAK LOW PRESSURE TRACKS ACROSS THE REGION TODAY THROUGH TONIGHT
AS A COLD FRONT PUSHES SOUTH. THE LOW MOVES OFF THE COAST
WEDNESDAY WHILE THE COLD FRONT SETTLES ACROSS THE CAROLINAS. HIGH
PRESSURE BUILDS INTO THE REGION FROM THE NORTH THURSDAY THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
PER LATEST WATER VAPOR...SHORTWAVE HAS REACHED EXTREME WRN VA. AT
THE SFC...COLD FRONT HAS MADE VERY LITTLE SRN PUSH FROM EARLIER
TODAY AS A STATIONARY FRONT REMAINS ALIGNED FROM THE LOWER MS
VALLEY INTO THE MID ATLANTIC REGION. WAVE ALONG THE STATIONARY
BOUNDARY OBSERVED ON RADAR/OBS LOCATED OVER CNTRL VA HAS HELPED
ENHANCE CONVECTION THIS AFTERNOON NORTH AND WEST OF RICHMOND. THIS
WILL CONTINUE TO BE THE CASE THROUGH THE AFTERNOON AND INTO THIS
EVENING AS WAVES ALONG THE FRONT CONTINUE TO IMPACT THE REGION.
THE MOST PROMINENT WAVE IS CURRENTLY LOCATED OVER ERN TN AND IS
ASSOCIATED WITH COOLING CLOUD TOPS. SFC WAVE WILL CONTINUE TO
STRENGTHEN AS IT PROGRESSES EWD ACROSS NRN NC/SRN VA LATE THIS
AFTERNOON...AIDED BY THE AFOREMENTIONED UPPER LEVEL SHORTWAVE.
THIS WILL PUSH THE FRONT EWD ACROSS THE AREA. AS THIS
OCCURS...BETTER PRECIP COVERAGE EXPECTED THROUGH THE EVENING.
THETA-E ADVECTION AND TEMPS IN THE LOW 80S AND DEWPOINTS IN THE
LOW 70S WILL MAINTAIN A MARGINALLY UNSTABLE AIRMASS (1000-1200
J/KG CAPE) ACROSS ERN VA INTO NERN NC. MARGINAL LOW LEVEL LAPSE
RATES AND LOW LEVEL WSWLY FLOW OF 30-40 KT MAY PRODUCE BRIEF GUSTY
WINDS UP TO 40 MPH UNDER THE STRONGEST STORMS. OVER CNTRL
VA...WEAK LAPSE RATES DUE TO DEEP MOISTURE (PRECIP WATERS ~2
INCHES) WILL PREVENT STRONGER WINDS FROM MIXING DOWN. WEAK TO
MARGINAL SHEAR WILL INHIBIT ANY ORGANIZED CONVECTION. THE MAIN
THREAT WILL CONTINUE TO BE HEAVY RAINFALL AS PRECIP WATER REMAIN
AROUND 150% OF NORMAL. TOTAL QPF AMOUNTS WILL GENERALLY RANGE FROM
ONE HALF INCH TO ONE INCH. SECONDARY SHORTWAVE WILL REACH NWRN VA
LATE TONIGHT...HELPING PUSH THE FRONT OFFSHORE. BEST MOISTURE WILL
ALSO BE SHUNTED OFFSHORE...BUT REMNANT MOISTURE AND SUBTLE FORCING
FOR ASCENT WILL RESULT IN CONTINUED SHOWERS THROUGH THE
OVERNIGHT...ESPECIALLY ALONG THE COAST. MILD TONIGHT WITH TEMPS IN
THE MID/UPPER 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
TROUGH AXIS WILL LOCATE ALONG THE MID ATLANTIC COAST WEDS...AS A
STRONG HIGH PRESSURE RIDGE BUILDS OVER THE PLAINS. WILL MAINTAIN
SLIGHT CHANCE POPS WEDS ALONG THE COAST FOR LIGHT SHOWERS AS
SUBTLE FORCING FOR ASCENT AND REMNANT MOISTURE REMAIN. CONFLUENCE
ALOFT WILL ALLOW COOL HIGH PRESSURE TO BUILD OVER THE GREAT LAKES
REGION...EXTENDING INTO THE MID ATLANTIC REGION. COMBINATION OF
NWLY FLOW...LOWER HEIGHTS AND DECREASING LOW LEVEL THICKNESS
VALUES WILL TRANSLATE TO TEMPS IN THE LOW 80S WEDS AFTERNOON.
REMNANT MOISTURE AND STEEP LOW LEVEL LAPSE RATES WILL PROVIDE FOR
GENERALLY PARTLY CLOUDY SKIES. N/NELY WINDS 10 TO 15 MPH. ONSHORE
WINDS ALONG THE COAST WILL KEEP TEMPS GENERALLY IN THE MID/UPPER
70S OVER THE MD/VA ERN SHORE (THANKS TO OCEAN TEMPS STILL IN THE
UPPER 60S) AND ALONG THE IMMEDIATE COAST.
BAGGY MID LEVEL TROUGH AND NWLY FLOW WILL CONTINUE TO IMPACT THE
MID ATLANTIC REGION THROUGH FRI. SFC HIGH PRESSURE WILL SLIDE
OFFSHORE THURS-FRI. ONSHORE WINDS WILL CONTINUE THROUGH FRIDAY.
FRONT CURRENTLY IMPACTING THE REGION WILL STALL OFF THE SE
COAST...WITH BEST MOISTURE REMAINING WELL SOUTH OF THE REGION.
MODELS SUGGEST POTENTIAL FOR DIURNALLY DRIVEN CONVECTION OVER THE
HIGHER TERRAIN...BUT EXPECT PRECIP TO STAY W OF THE FA. TEMPS WILL
REMAIN SLIGHTLY BELOW NORMAL AS NWLY FLOW AND ONSHORE WINDS
CONTINUE (MID 80S...COOLER ALONG THE IMMEDIATE COAST). COOL
MORNING TEMPS THROUGH THE SHORT TERM WITH TEMPS GENERALLY IN THE
LOW 60S. SOME INLAND LOCALES (ESPECIALLY OVER THE ERN VA PIEDMONT)
WILL FALL INTO THE UPPER 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A RATHER BENIGN PATTERN IS EXPECTED THIS 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 INTO THE MID/UPPER
80S SATURDAY...TO THE UPPER 80S SUNDAY...AND EVENTUALLY TO THE UPPER
80S/LOW 90S BY MONDAY AND TUESDAY. LOW TEMPERATURES SHOULD TREND
UPWARD FROM AROUND 65 EARLY IN THE PERIOD TO THE UPPER 60S/LOW 70S
LATE IN THE PERIOD.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SHOWERS WITH EMBEDDED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON
AND EVENING AS A COLD FRONT SLOWLY MOVES ACROSS THE AREA. THE MAIN
IMPACT WILL BE LOCALIZED HEAVY RAINFALL AND GUSTY WINDS. EXPECT
CIGS AND VIS TO LOWER BRIEFLY INTO MVFR (AND POSSIBLY IFR)
CONDITIONS UNDER STRONGER STORM CORES. CONVECTIVE ACTIVITY IS
EXPECTED TO WANE AFTER MIDNIGHT AS THE FRONT PUSHES OFFSHORE BY
DAYBREAK WEDNESDAY MORNING. FOG MAY BE POSSIBLE THROUGHOUT THE
REGION LATE TONIGHT INTO THE MORNING AS WELL.
SHOWERS ARE EXPECTED TO LINGER NEAR THE COAST WEDNESDAY MORNING
BEFORE THE FRONT MOVES FARTHER OUT TO SEA. OTHERWISE...CONDITIONS
WILL START TO DRY OUT AND SKIES WILL GRADUALLY CLEAR FROM
NORTHWEST TO SOUTHEAST AS HIGH PRESSURE BUILDS INTO THE MID
ATLANTIC REGION FROM THE NORTHWEST. HIGH PRESSURE AND VFR
CONDITIONS WILL THEN DOMINATE THE WEATHER PATTERN FOR THE REST OF
THE WEEK INTO THE WEEKEND.
&&
.MARINE...
A FRONTAL BOUNDARY IS ALIGNED SW-NE ACROSS THE MID-ATLANTIC REGION
THIS AFTERNOON WITH SEVERAL WAVES OF LOW PRESSURE ALONG THE FRONT.
THE WESTERNMOST AREA OF LOW PRESSURE OVER W-CENTRAL NC WILL LIFT ENE
OVERNIGHT AND PULL OFF THE COAST EARLY WEDNESDAY MORNING. A BRIEF
SHALLOW NORTHERLY CAA SURGE SHOULD FOLLOW AS THE LOW PULLS OFF THE
COAST. THERE IS A TENDENCY FOR MODELS TO UNDER-ESTIMATE THESE TYPE
OF SURGES...SO A SHORT-DURATION LOW-END SCA HAS BEEN ISSUED FOR THE
BAY/LOWER JAMES/SOUND FROM 08-14Z (4-10AM). AS FOR THE OCEAN...THE
WIND WILL PROGRESSIVELY BECOME NE THROUGH THE DAY WEDNESDAY AS HIGH
PRESSURE BUILDS OFF OF CAPE COD. AT THIS TIME THE STRENGTH OF THE
FLOW IS NOT EXPECTED TO BE STRONG ENOUGH TO BUILDS SEAS TO 5FT...SO
NO SCA AT THIS TIME. THE HIGH LINGERS OFF THE NORTHEAST COAST
THROUGH THE END OF THE WEEK...AS A WEAK AREA OF LOW PRESSURE REMAINS
QUASI-STATIONARY OFF THE NC OUTER BANKS. THIS WILL MAINTAIN STEADY
10-15KT ONSHORE FLOW...WHICH WILL HELP MAINTAIN 3-4FT SEAS. THE HIGH
SLOWLY SINKS S OFF THE COAST DURING THE WEEKEND WITH THE WIND
SHIFTING TO S AND REMAINING AOB 15KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 AM EDT WEDNESDAY FOR
ANZ630>634-638.
&&
$$
SYNOPSIS...ALB
NEAR TERM...SAM
SHORT TERM...SAM
LONG TERM...AJZ
AVIATION...BMD
MARINE...AJZ
