Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 160758
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 AM EDT WED APR 16 2014

.SYNOPSIS...

HIGH PRESSURE WILL BUILD OVERHEAD DURING MIDWEEK...BEFORE MOVE OFFSHORE
LATE IN THE WEEK. AN AREA OF LOW PRESSURE MAY AFFECT THE AREA SATURDAY.

&&

.NEAR TERM /TODAY/...

AS OF 07Z...1028MB SFC HIGH CENTERED OVER SWRN OHIO WILL INTENSIFY
AS IT MOVES NORTHEAST ACROSS THE NRN MID-ATLANTIC TODAY. PRESSURE
GRADIENT SLOWLY DECREASES THROUGH THE DAY...WITH NWLY GUSTS OF 30 TO
35 MPH EASING THROUGH THE AFTERNOON AND BECOMING NLY. NELY FLOW
TONIGHT AS A SFC RIDGE STALLS OVER THE AREA...SETTING UP COLD AIR
DAMMING THAT WILL PERSIST INTO THE WEEKEND. MAX TEMPS AROUND 50F
TODAY CWA WIDE (LOW 50S S OF KCHO).

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...

MIN TEMPS TONIGHT WILL BE MODERATED FROM NELY FLOW COMING OFF MID
40S OCEAN TEMPS AND LOW 50S BAY TEMPS. LEFT FREEZE WARNING DECISION
TO DAY SHIFT SINCE MOST GUIDANCE HAS ZONES IN THE LOW 30S. PIEDMONT
AND CENTRAL FOOTHILLS AREAS HAVE THE BEST CHANCE OF SEEING
SUBFREEZING TEMPS TONIGHT.

LOW CLOUDS SPREAD EAST INTO SRN MD THURSDAY AS THE ONSHORE FLOW
SATURATES. MAX TEMPS GENERALLY INCREASE NE TO SW BASED ON ONSHORE
FLOW...MID 50S FOR NERN MD TO UPR 50S/LOW 60S IN CNTRL SHEN VLY/KCHO.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...

HIGH PRES OVR NEW ENGLAND WL BE TRACKING SLOWLY NE THU NGT AND
FRI...LVG THE MID ATLC IN A WEDGING SITUATION WHICH IS XPCTD TO
LEAD TO A PD OF CAD CONDITIONS - NERLY LO LVL WINDS WHICH WL
CREATE A LOW CLD DECK OVR THE RGN E OF THE MTNS. THE SUNNIEST
PLACE IN THE FCST AREA FRI WL LKLY BE W OF THE BLUE RDG. NO PCPN
IS XPCTD - IF ANYTHING WERE TO DVLP IT WOULD BE DZ. LOWS THU NGT
IN THE 30S/L40S. HIGHS FRI 55-60.

ON SAT AN UPR LVL TROF WL TRACK N OF THE AREA...BUT WL DRAG A CD
FNT THRU THE RGN. SOMETIMES CAD ENVIRONMENTS OF LO CLDS CAN HANG
ARND IN THE MID ATLC UP TO 4 DAYS...BUT THIS DOES NOT LOOK TO BE
THE CASE THIS TIME...AS CD FOPA IS PRBLY THE #1 WAY TO DISLODGE
CAD. BUT W/ THIS WL ALSO COME THE PSBLTY OF RA. HIGHS SAT IN THE
M60S.

SUN LOOKING TO BE THE BETTER DAY OF THE WKND FOR OUTDOOR
ACTIVITIES - SKIES SHOULD CLR AS HIGH PRES RETURNS. LOWS SAT NGT
U30S/L40S. HIGHS IN THE LM60S.

TEMPS XPCTD TO SLOWLY CLIMB DURG THE 1ST PART OF THE NEW WK W/ UPR
LVL FLOW MORE OR LESS ZNL. BY TUE HIGH TEMPS SHOULD BE BACK ABV 70
ACROSS MUCH OF THE AREA.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...

VFR THROUGH TAF PERIOD AND GUSTY TODAY AS HIGH PRESSURE BUILDS
NORTHEAST ACROSS THE REGION. NW WINDS GUSTING AROUND 30 KT EARLY
THIS MORNING SLOWLY EASE THROUGH THE DAY. ONSHORE FLOW FROM COLD AIR
DAMMING RIDGE TONIGHT...THURSDAY (CONTINUING INTO SATURDAY).

A CAD SET UP IN XPCTD THU NGT/FRI. THIS WOULD LKLY LEAD TO CIGS IN
THE MVFR RNG. A CD FNT IS XPCTD TO MOVE INTO THE AREA SAT WHICH
COULD PSBLY SPAWN RA/RW. VFR CONDS XPCTD SUN AS HIGH PRES RETURNS.

&&

.MARINE...

NWLY GALES OBS HAVE BEEN FAIRLY FEW AND FAR BETWEEN...EXCEPT WHERE
CHANNELING IS OCCURRING (SUCH AS AT COVE PT WHICH HAS HAD GUSTS
AROUND 40 KT). DCA HAD A 240 AM PEAK GUST OF 34 KT...SO THE GALE
WARNING WILL REMAIN UP FOR NOW FOR ALL WATERS. WILL PROBABLY BE ABLE
TO DROP BEFORE 6AM FOR NWRN PORTIONS OF THE WATERS...BUT EXTENDED
UNTIL 9AM FOR LOWER SRN MD WATERS FOR CONTINUED CHANNELING. SCA FOR
ALL WATERS TO 2PM AND MOST MD BAY UNTIL 6PM. FLOW BECOMES NELY THIS
EVENING...INCREASING TO 20 KT FOR LOWER SRN MD WATERS AFTER MIDNIGHT
(WHEN AN SCA GOES INTO EFFECT)...THEN EXPANDING UP THE REST OF THE
MD BAY BEFORE SUNRISE. ALL BUT THE UPPER TIDAL POTOMAC IN AN SCA FOR
THE DAY THURSDAY WITH NELY FLOW GUSTING AROUND 20 KT.


SMALL CRAFT ADVISORY LEVEL WIND GUSTS ARE POSSIBLE FOR PARTS OF
THE WATERS SAT NIGHT IN A TIGHTENING PRESSURE GRADIENT BETWEEN
LOW PRESSURE DEPARTING TO THE NORTH AND HIGH PRESSURE BUILDING IN
FROM THE WEST.

&&

.TIDES/COASTAL FLOODING...

STRONG NW WINDS HV CAUSED WATER LEVELS IN THE CHES BAY TO DROP TO 1
TO 1.5 FT BLO NRML. TIDAL BLOWOUT CONDITIONS ARE EXPECTED TO CONTINUE
TODAY WITH ANOMALIES UP TO 2 FEET BELOW NORMAL. MWS HAS BEEN ISSUED FOR
THIS. WATER LVLS SHOULD BEGIN TO RECOVER THIS AFTN.

&&

.CLIMATE...

A VERY COLD AIRMASS FOR MID APRIL IS CAUSING TEMPS TO APPROACH
RECORD MINIMUM TEMPERATURES THIS MORNING. BELOW IS A TABLE OF RECORD
MINIMUM TEMPERATURES FOR APRIL 16 ALONG WITH THE 3 AM TEMPS.

SITE...RECORD LOW TEMP   3 AM WED TEMP
DCA....29 F IN 1928      35
BWI....30 F IN 1962      33
IAD....28 F IN 1981      32

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     DCZ001.
     FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR DCZ001.
MD...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     MDZ004>007-009>011-013-014-016>018.
     FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ011-013-014-
     016>018.
     FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ004>007-009-
     010.
VA...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     VAZ036>040-042-050>057-501-502.
     FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ052>057.
     FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ036>040-042-
     050-051-501-502.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT THIS
     EVENING FOR ANZ531-532-537-539>541.
     SMALL CRAFT ADVISORY FROM 3 AM TO 6 PM EDT THURSDAY FOR
     ANZ530>533-538>541.
     GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ530>532-
     535>542.
     SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 2 PM EDT THIS
     AFTERNOON FOR ANZ530-535-536-538-542.
     SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT THURSDAY FOR ANZ536-
     542.
     SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EDT THIS
     EVENING FOR ANZ533-534-543.
     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EDT
     THURSDAY FOR ANZ534-537-543.
     GALE WARNING UNTIL 9 AM EDT THIS MORNING FOR ANZ533-534-543.

&&

$$
PRODUCTS...BAJ/WOODY!







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