896
FXUS61 KLWX 140752
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
352 AM EDT FRI AUG 14 2020
SYNOPSIS
A SURFACE FRONT WILL MEANDER OVER THE REGION THROUGH THE
WEEKEND, BRINGING SHOWERS AND THUNDERSTORMS EACH DAY. LOW
PRESSURE WILL DEVELOP ON THIS FRONT AND MOVE ACROSS THE REGION
SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE WILL THEN BRIEFLY
RETURN EARLY NEXT WEEK BEFORE AN UNSETTLED PATTERN LIKELY
RETURNS BY THE MIDDLE OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
SEEING SEVERAL SHOWERS THAT HAVE DEVELOPED OVER CENTRAL VA AND
ALONG THE CHESAPEAKE BAY. THIS IS ASSOCIATED WITH ONSHORE FLOW
NORTH OF A DEEPENING SURFACE LOW ALONG THE NC COAST. THESE ARE
PROGRESSIVE ENOUGH THAT FLOODING IS NOT A CONCERN AT THIS POINT
WITH THIS SHOWER ACTIVITY.
ELSEWHERE ACROSS THE AREA, MOSTLY CLOUDY SKIES HAVE PREVAILED,
AND WILL CONTINUE TO DO SO THROUGH DAYBREAK. SOME PATCHY FOG
SEEMS TO BE TRYING TO DEVELOP IN A FEW SPOTS, BUT VISIBILITIES
AREN'T DROPPING ALL THAT MUCH. THINKING THE CLOUD COVER WILL
KEEP FOG COVERAGE FAIRLY LOW AS WE HEAD INTO SUNRISE.
FOR THE REST OF TODAY, A FRONTAL BOUNDARY TO OUR NORTH WILL DROP
SOUTH THROUGH THE AREA TODAY. MEANWHILE, A SLOW MOVING UPPER LOW
WILL BE APPROACHING FROM THE WEST. THIS WILL LEAD TO MORE
SHOWERS AND STORMS TODAY, ESPECIALLY INTO THE AFTERNOON HOURS.
HI-RES GUIDANCE DOESN'T PAINT AN OMINOUS PICTURE TODAY, WITH QPF
AMOUNTS MUCH LIGHTER THAN IN PREVIOUS DAYS ON THE 00Z HREF.
ADDITIONALLY, ANY SHOWERS/STORMS SHOULD BE RELATIVELY
PROGRESSIVE (AS WE ARE SEEING THIS MORNING). OF COURSE, GIVEN
THE ANTECEDENT CONDITIONS ACROSS A MAJORITY OF THE AREA, WILL
HAVE TO WATCH FOR ANY HEAVIER ELEMENTS THAT MAY TRY TO TRAIN
ALONG THE FRONT ITSELF. HOWEVER, WITH THE FRONT ACTUALLY MOVING
TODAY, THINK THIS WILL BE HARDER TO DO.
A BRIEF LULL IN ACTIVITY IS POSSIBLE OVERNIGHT TONIGHT FOR MUCH
OF THE AREA, THOUGH DO EXPECT LINGERING SHOWERS OVERNIGHT IN
CENTRAL VA AND EASTERN WV. OVERNIGHT LOWS INTO THE UPPER 60S/LOW
70S (UPPER 50S TO LOW 60S IN THE HIGHER ELEVATIONS).
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
ON SATURDAY, THE SLOW-MOVING UPPER TROUGH OVER THE OHIO VALLEY
WILL FINALLY SWING THROUGH THE REGION. ADDITIONALLY, AT THE
SURFACE, THE AFOREMENTIONED FRONTAL BOUNDARY WILL REMAIN OVER
CENTRAL VA. MEANWHILE, A SURFACE LOW WILL DEVELOP EAST OF THE
UPPER TROUGH AND LATCH ONTO THIS FRONT. THIS WILL RESULT IN LOW
PRESSURE MOVING JUST TO THE SOUTH OF THE REGION LATER SATURDAY
INTO EARLY SUNDAY. THE TRACK MAY MOVE RIGHT OVER SOME OF OUR
SOUTHERN ZONES. ONSHORE FLOW ASSOCIATED WITH THIS SYSTEM COULD
LEAD TO LOCALLY ENHANCED RAINFALL ALONG THE RIDGES AND IN THE
POTOMAC HIGHLANDS. GUIDANCE THEN TAKES THE LOW ACROSS SOUTHERN
MD INTO THE DELMARVA OVERNIGHT, WHILE ALSO GRADUALLY
STRENGTHENING IT. RAINFALL AMOUNTS COULD ALSO BE LOCALLY BE
ENHANCED FROM CENTRAL VIRGINIA TO SOUTHERN MARYLAND, WHERE
THEY'LL STAND THE BEST CHANCE OF DESTABILIZING AND DEVELOPING
SOME CONVECTIVE ELEMENTS. WITH THE CONTINUED CLOUDS AND STORMS,
HIGHS WILL CONTINUE TO BE IN THE 80S. LOWS WILL BE IN THE 60S
TO 70S.
ALL THIS BEING SAID, LOOKING AT A POTENTIAL FOR FLOODING
SATURDAY/SATURDAY NIGHT. CURRENT FORECAST SHOWS 2-3 INCHES OF
RAIN WITH THIS SYSTEM ACROSS CENTRAL VA AND INTO SOUTHERN MD.
SOME LOCALLY HIGHER AMOUNTS ARE LIKELY WITH CONVECTIVE ELEMENTS
AND UPSLOPE FLOW. GIVEN THE RECENT HEAVY RAINS, IT ISN'T GOING
TO TAKE MUCH TO CAUSE MORE FLOODING ISSUES.
BY SUNDAY MORNING, THE LOW SHOULD BE PUSHING OFF TO THE EAST,
TAKING THE RAIN WITH IT. SOME GUIDANCE IS A LITTLE SLOWER
HOWEVER, SO LEAVING SOME POPS IN THROUGH THE EARLY AFTERNOON.
THOUGH, DO THINK THERE IS A GOOD SHOT WE ARE DRY BY EARLY
AFTERNOON. SUNDAY WILL BE MUCH COOLER THAN NORMAL, WITH HIGHS IN
THE MID TO UPPER 70S (LOW 80S CLOSER TO THE WATER). JUST HOPE WE
CAN GET THE RAIN OUT OF HERE EARLY ENOUGH TO ENJOY IT. SUNDAY
NIGHT WILL BE DRY, WITH LOWS RANGING FROM THE MID 50S IN THE
HIGHER ELEVATIONS TO UPPER 60S IN THE TYPICAL NORMAL AREAS ALONG
THE WATERS.
LONG TERM /MONDAY THROUGH THURSDAY/
TROUGHINESS WILL DOMINATE THE EAST COAST STATES THE FIRST HALF OF
NEXT WEEK KEEPING TEMPS AOB NORMAL. THERE WILL BE DRYING FOR THE
FIRST PART OF THE WEEK AS NW FLOW DEVELOPS IN THE WAKE OF LOW
PRESSURE ORGANIZING OFFSHORE. BY THE MIDDLE OF THE WEEK, MOISTURE
BEGINS TO INCREASE AS SFC HIGH MOVES OFFSHORE AND SRLY FLOW
DEVELOPS. HOWEVER, MOISTURE SUPPLY IS NOT EXPECTED TO BE ANYWHERE
CLOSE TO THE PAST FEW DAYS, SO THE RISK OF EXCESSIVE RAINFALL
APPEARS LOW AT THIS TIME. RIDGING TRIES TO BUILD ALONG THE EAST
COAST FOR THE SECOND HALF OF NEXT WEEK LIKELY LIMITING AREAL
COVERAGE OF SHOWERS AND T-STORMS.
AVIATION /07Z FRIDAY THROUGH TUESDAY/
CURRENTLY SEEING PLENTY OF LOWER CLOUDS THIS MORNING THANKS TO
PLENTIFUL LOW-LEVEL MOISTURE FLOWING INTO THE AREA IN ONSHORE
FLOW. FOG WILL STRUGGLE TO FORM THIS MORNING THOUGH, WITH VERY
LITTLE IN TERMS OF CLEARING AND WINDS OF 5-10 KTS. IFR
CONDITIONS WILL PERSIST THROUGH 13Z OR SO FOR MOST TERMINALS
DUE TO LOW CIGS. CLOUDS WILL GRADUALLY LIFT THROUGH THE DAY, BUT
LIKELY REMAIN MVFR MUCH OF THE DAY. SHOWERS AND STORMS POSSIBLE
AGAIN TODAY, BUT CONFIDENCE TOO LOW IN EXACT PLACEMENT TO ADD
INTO TAFS AT THIS TIME. DO THINK THE BEST SHOT WILL BE FOR
CHO/MRB THOUGH.
MORE SIGNIFICANT CHANCE FOR RAINFALL WILL MOVE INTO THE REGION
SATURDAY AFTERNOON AND CONTINUE THROUGH EARLY SUNDAY, AS LOW
PRESSURE TRACKS ALONG A STATIONARY FRONT TO OUR SOUTH. LOCALLY
HEAVY RAIN IS POSSIBLE WITH THIS SYSTEM, AND POTENTIALLY SOME
EMBEDDED THUNDERSTORMS (PRIMARILY TOWARDS CHO). VSBY/CIG
RESTRICTIONS LIKELY DURING THIS TIME.
CONDITIONS BEGIN TO CLEAR LATER IN THE DAY ON SUNDAY, AS LOW
PRESSURE PUSHES OFF TO THE EAST, WITH HIGH PRESSURE BUILDING IN
BEHIND IT AND VFR CONDITIONS RETURNING.
NO SIG WX EXPECTED THE FIRST HALF OF NEXT WEEK.
MARINE
GENERALLY SUB-SCA CONDITIONS EXPECTED ON THE WATERS THROUGH
SATURDAY. MAIN CONCERN EACH DAY WILL BE THUNDERSTORMS, PRIMARILY
DURING THE AFTERNOON HOURS, THOUGH SOME MAY DEVELOP DURING THE
MORNINGS. GUSTY WINDS AND EVEN A FEW WATERSPOUTS WILL BE
POSSIBLE WITH STRONGER STORMS.
ONSHORE FLOW IS EXPECTED TO PERSIST SUNDAY, AND MAY BE NEAR SMALL
CRAFT ADVISORY (SCA) LEVELS.
SCA CONDITIONS POSSIBLE MONDAY MORNING. OTHERWISE, WINDS SHOULD
DIMINISH THROUGH TIME NEXT WEEK.
TIDES/COASTAL FLOODING
MINOR COASTAL FLOODING IS POSSIBLE LATE SAT NIGHT AND SUN AS ONSHORE
FLOW STRENGTHENS AS LOW PRESSURE PASSES TO THE SOUTH.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...CJL
NEAR TERM...CJL
SHORT TERM...CJL/KJP
LONG TERM...LFR
AVIATION...LFR/CJL
MARINE...LFR/CJL
TIDES/COASTAL FLOODING...LFR
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