Severe Thunderstorm Warning 27, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
900 PM EDT SUN MAY 1 2016

.SYNOPSIS...
A FRONT WILL REMAIN STATIONARY ACROSS THE AREA THROUGH
TONIGHT THEN LIFT NORTH AS A WARM FRONT MONDAY. A COLD FRONT WILL
SLOWLY MOVE THROUGH MONDAY EVENING WITH MULTIPLE SURFACE WAVES
MOVING ACROSS THE AREA. ANOTHER COLD FRONT IS EXPECTED TUESDAY
NIGHT AND HIGH PRESSURE WILL BRIEFLY RETURN FOR WEDNESDAY. LOW
PRESSURE MAY IMPACT THE AREA THURSDAY AND FRIDAY BEFORE HIGH
PRESSURE RETURNS DURING THE WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
A STATIONARY FRONT REMAINS DRAPED FROM WESTERN MARYLAND THROUGH
THE SHENANDOAH VALLEY INTO NORTH CAROLINA. A COOL EASTERLY FLOW
WILL CONTINUE FOR AREAS NORTH AND EAST OF THE BOUNDARY...RESULTING
IN LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE AND AREAS OF FOG. FOG
MAY BE DENSE... ESPECIALLY ACROSS HILLTOPS AND HIGHER ELEVATIONS.
A DENSE FOG ADVISORY MAY BE NEEDED FOR PORTIONS OF THE AREA
OVERNIGHT. CONFIDENCE IS TOO LOW FOR AN ADVISORY AT THIS TIME WITH
CONCERN BEING THAT THE STRATUS DECK MAY PREVENT WIDESPREAD VSBYS
AT OR BELOW ONE-QUARTER MILE.

A FEW SHOWERS AND THUNDERSTORMS HAVE POPPED UP NEAR AND TO THE
SOUTH AND WEST OF THE BOUNDARY OVER THE SHENANDOAH VALLEY AND
POTOMAC HIGHLANDS. THIS ACTIVITY WILL SPREAD EAST THROUGH THE REST
OF THE CWA LATE THIS EVENING INTO THE OVERNIGHT HOURS.
HOWEVER...IT SHOULD WEAKEN AS IT MOVES INTO THE COOLER AIR.

MORNING LOW CLOUDS AND FOG WILL GRADUALLY ERODE MON MORNING WITH
TEMPS RISING INTO THE 70S AS WARM FRONT LIFTS INTO PA. SOME
DESTABILIZATION IS LIKELY TO TAKE PLACE IN THE AFTERNOON WITH SCT
SHOWERS AND T-STORMS EXPECTED. BEST INSTABILITY IS EXPECTED OVER
THE SRN HALF AND EAST OF THE BLUE RIDGE WHERE CDFNT WILL NOT CLEAR
THOSE AREAS UNTIL EVENING. A FEW SEVERE THUNDERSTORMS ARE POSSIBLE
ACROSS THESE AREAS...WITH DAMAGING WINDS AND LARGE HAIL BEING THE
PRIMARY THREATS.

&&

.SHORT TERM /MONDAY NIGHT/...
MOISTURE ADVECTION CONTINUES MON NIGHT IN SOUTHWEST FLOW AHEAD OF
700-500 MB WAVE. MULTIPLE SFC WAVES ARE EXPECTED TO CROSS THE AREA
MON NIGHT ALONG SLOW MOVING BDRY TO BRING ANOTHER ROUND OF MDT
PRECIP.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
ANOTHER IN A SERIES OF LOW PRESSURE WAVES WILL CROSS THE AREA
TUESDAY...THEN DEPART TO THE NORTHEAST TUESDAY NIGHT INTO
WEDNESDAY AS A STUBBORN FRONT REMAINS DRAPED OVER THE AREA.

A LARGE/COLD UPPER LOW WILL DIVE OUT OF CANADA STRAIGHT SOUTH TO
OVER THE MID-ATLANTIC THURSDAY...THEN SLOWLY PIVOT OFF TO THE EAST
THROUGH FRIDAY LEADING TO A CONTINUATION OF UNSETTLED WEATHER.
MODELS ARE MODEST WITH INSTABILITY IN SOUNDINGS AT THIS TIME BUT
COULD SEE AN INCREASING TREND GIVEN THE COLD AIR ALOFT IF FLOW TAKES
ON A MORE SOUTHERLY/WARM COMPONENT IN THE LOW-LEVELS WEDNESDAY.

AFTER THIS UPPER LOW LIFTS OUT...A LARGE AREA OF HIGH PRESSURE WILL
BEGIN BUILDING JUST OFF THE SOUTHEAST COAST LEADING TO A STRONG
WARMING TREND BEGINNING OVER THE WEEKEND.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
AN EASTERLY FLOW WILL RESULT IN MORE LOW CLOUDS ALONG WITH DRIZZLE
AND AREAS OF FOG. IFR/SUBIFR CONDITIONS ARE EXPECTED OVERNIGHT
INTO MONDAY MORNING. FOG MAY BE DENSE OVERNIGHT WITH VSBYS AROUND
ONE-QUARTER MILE POSSIBLE. A FEW SHOWERS AND PERHAPS AND ISOLATED
THUNDERSTORM WILL PASS THROUGH THE TERMINALS LATE THIS EVENING.
CONFIDENCE FOR THUNDER IS TOO LOW TO MENTION IN THE TAFS AT THIS
POINT...BUT WILL HAVE TO BE MONITORED. LOW CLOUDS AND FOG WILL
LIFT MONDAY MORNING. SCT T-STORMS EXPECTED MONDAY AFTERNOON AND
EVENING WITH ANOTHER ROUND OF MDT RAIN MON NIGHT.

SUB-VFR PSBL TUE-WED IN ANY LWR CIGS/SHWRS W/ FRONT STALLED
NEARBY. WINDS GENERALLY ELY 10 KTS.

&&

.MARINE...
WINDS GENERALLY BELOW SCA BUT GUSTY NEAR T-STORMS
ESPECIALLY MON AFTERNOON MIDDLE AND LOWER PORTIONS OF POTOMAC AND
CHES BAY.

A WEAK PRESSURE GRADIENT WILL PREVAIL OVER THE WATERS WITH A
FRONT STALLED NEARBY...LEADING TO GUSTS THAT SHOULD STAY LARGELY
BELOW SMALL CRAFT ADVISORY LEVELS DURING THE MIDDLE OF THE WEEK.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

SYNOPSIS...LFR
NEAR TERM...BJL/LFR
SHORT TERM...LFR
LONG TERM...DFH
AVIATION...BJL/LFR/DFH
MARINE...BJL/LFR/DFH

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