387
FXUS61 KLWX 131848
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
248 PM EDT THU AUG 13 2026
WHAT HAS CHANGED
WHILE ISOLATED SHOWERS REMAIN POSSIBLE THIS AFTERNOON NEAR THE
I-64 CORRIDOR, IT IS LOOKING A BIT LESS LIKELY GIVEN THE LACK OF
CUMULUS DEVELOPMENT THUS FAR. OTHERWISE, FOR FRIDAY, 12Z HIGH-
RESOLUTION MODELS SEEM TO FAVOR AREAS SOUTH OF U.S. 50 FOR THE
BETTER SHOT FOR ANY STRONGER CONVECTION. INSTABILITY DROPS OFF
PRETTY QUICKLY WITH NORTHWARD EXTENT.
KEY MESSAGES
- 1) SEASONABLY WARM WITH INCREASING SHOWER CHANCES HEADING INTO
FRIDAY, BEFORE TURNING DRIER TO START THE WEEKEND.
- 2) SHOWERS AND THUNDERSTORMS POSSIBLE BETWEEN SUNDAY AND
MONDAY AHEAD OF DRIER CONDITIONS NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...SEASONABLY WARM WITH INCREASING SHOWER CHANCES
HEADED INTO FRIDAY, BEFORE TURNING DRIER TO START THE WEEKEND.
BEING ALONG THE EASTERN FLANK OF THE SPRAWLING UPPER RIDGE
ACROSS THE SOUTHERN U.S., NORTHWESTERLY FLOW PERSISTS ALOFT. AT
THE SURFACE, A WAVY STALLED BOUNDARY PERSISTS ALONG THE
VIRGINIA/NORTH CAROLINA BORDER STRETCHING BACK TOWARD THE GREAT SMOKY
MOUNTAINS. TO THE NORTH OF THIS FRONTAL ZONE, THE LOCAL AREA
CONTINUES TO SEE FAIRLY TRANQUIL WEATHER. ALTHOUGH THE USUAL
SUMMERTIME GRADIENTS ARE ON THE WEAKER SIDE, AMPLE BOUNDARY
LAYER MIXING IS YIELDING SOME NORTHWESTERLY GUSTS UP TO 15 TO 20
MPH. THIS IS OCCURRING UNDERNEATH SCATTERED FAIR WEATHER CUMULUS
AND SOME THIN HIGH CIRRUS MOVING IN FROM THE LOWER GREAT LAKES.
WITH EARLY AFTERNOON TEMPERATURES IN THE 80S, EXPECT FURTHER
SURFACE HEATING TO CARRY HIGHS INTO THE UPPER 80S TO LOW 90S.
ADDING DEW POINTS IN THE MID/UPPER 60S WILL CARRY AFTERNOON HEAT
INDEX VALUES INTO THE LOW/MID 90S.
IN TERMS OF SHOWER CHANCES, WHILE A FEW 12Z HIGH-RESOLUTION
MODELS DEPICT SOME CONVECTION ACROSS CENTRAL VIRGINIA, A LACK OF
CUMULUS DEVELOPMENT SUGGESTS OTHERWISE. WILL MAINTAIN ISOLATED
SHOWERS TOWARD SUNDOWN, BUT ANY ACTIVITY DOES NOT APPEAR
IMMINENT BASED ON THE GOES-19 VISIBLE SATELLITE CHANNEL. HEADING
INTO THE EVENING AND OVERNIGHT, SOME INCREASE IN CLOUDS ARE
EXPECTED WITH OVERNIGHT LOWS ALONG/EAST OF U.S. 15 IN THE
LOW/MID 70S. WEST OF THIS HIGHWAY, MAINLY 60S CAN BE EXPECTED.
FRIDAY STILL PRESENTS A MIXED SIGNAL IN TERMS OF HOW ACTIVE THE
WEATHER MAY BECOME. THE MENTIONED BOUNDARY NEAR THE
VIRGINIA/NORTH CAROLINA BORDER IS FORECAST TO SLOWLY EDGE
NORTHWARD IN TIME. HOWEVER, ITS NORTHWARD PROGRESSION LIKELY
DOES NOT CARRY IT EVEN PAST SOUTHERN VIRGINIA. AS A RESULT, THE
BETTER INSTABILITY LIKELY STAYS OFF TO THE SOUTH WHICH WOULD
INFLUENCE OVERALL CONVECTIVE CHANCES. ONE OTHER ADDITIONAL ITEM
TO ADDRESS IS THE NOCTURNAL MESOSCALE CONVECTIVE SYSTEM (MCS)
EXPECTED TO BE CROSSING THE OHIO VALLEY EARLY FRIDAY. THE 12Z
HREF 40 DBZ PAINTBALL PLOT SHOWS MOST OF THIS COMPLEX DIVING
SOUTHEASTWARD ACROSS EASTERN KENTUCKY INTO SOUTHWESTERN
VIRGINIA. THIS WOULD LARGELY RIDE ALONG THE INSTABILITY GRADIENT
WHICH WOULD FAVOR KEEPING A BULK OF THIS ACTIVITY OUT OF THE
LOCAL AREA. SOME DECAYING SHOWERS COULD IMPACT THE CENTRAL
SHENANDOAH VALLEY/BLUE RIDGE REGION DURING THE MID/LATE MORNING
HOURS. ABUNDANT CLOUD COVER SHOULD LINGER OVER A BULK OF THE
AREA WHICH MAY HINDER SUBSEQUENT DIURNAL CONVECTION. INSTABILITY
IS A BIT HIGHER SOUTH OF U.S. 50 WHICH LIKELY DELINEATES THE
AREA TO SEE STRONG TO SEVERE CONVECTION. THIS LARGELY MATCHES
THE MARGINAL RISK AREA FROM THE STORM PREDICTION CENTER.
DAMAGING WIND GUSTS WOULD BE THE PRIMARY THREAT FOR ANY MORE
INTENSE CELL. OTHERWISE, EXPECT MOSTLY CLOUDY SKIES WITH HIGHS
IN THE 80S (70S FOR THE MOUNTAINS), AMIDST LIKELY EAST TO
NORTHEASTERLY WINDS. SOME OVERNIGHT SHOWERS MAY LINGER ACROSS
PORTIONS OF THE REGION. FORECAST LOWS WILL BE IN THE 60S TO LOW
70S WITH CONTINUED OVERCAST CONDITIONS.
ON SATURDAY, SURFACE HIGH PRESSURE BEGINS TO BUILD ACROSS
ONTARIO DOWN INTO NEW ENGLAND WHILE THE STALLED FRONT SAGS
FURTHER SOUTH. THIS WILL FAVOR AN ONSHORE FLOW REGIME WITH WINDS
OUT OF THE EAST TO NORTHEAST. CONSEQUENTLY, THERE SHOULD BE
ADDED CLOUD COVER ACROSS THE REGION WHICH WILL YIELD A MIX OF
CLOUDS AND SUN. WHILE MANY STAY DRY ON SATURDAY, ADDITIONAL
PERTURBATIONS IN THE NORTHWESTERLY FLOW ALOFT SHOULD INCREASE
SHOWER CHANCES WEST OF I-95. SOME OF THIS ACTIVITY COULD EDGE
EASTWARD TO THE I-95 CORRIDOR BY LATE SATURDAY NIGHT. OVERALL
HIGH TEMPERATURES WILL BE IN THE LOW/MID 80S, WITH 70S ACROSS
THE HIGHER TERRAIN. NIGHTTIME LOWS SHOULD REMAIN VERY CLOSE TO
THE PREVIOUS NIGHT.
KEY MESSAGE 2...SHOWERS AND THUNDERSTORMS POSSIBLE BETWEEN
SUNDAY AND MONDAY AHEAD OF DRIER CONDITIONS NEXT WEEK.
BEGINNING THIS WEEKEND, AN UPPER-LEVEL PERTURBATION FORMS OVER THE
CANADIAN ROCKIES AND TRACKS EASTWARD, WITH A TROUGH FORMING OVER THE
NORTHEAST BY SUNDAY. THE RESULTANT FRONTAL BOUNDARY WILL BRING
INCREASED CHANCES FOR SHOWERS & THUNDERSTORMS BEGINNING SUNDAY
AFTERNOON AND LINGERING INTO MONDAY AS IT TRACKS OFFSHORE. AS THIS
GRADIENT PUSHES THROUGH, SOME SEVERE STORMS ARE POSSIBLE OUT OF THIS
SYSTEM. MODELS HAVE SHIFTED PROBABILITIES NORTHWARD TO OUR AREA HERE
OVER THE MID-ATLANTIC COMPARED TO MORE SOUTHWARD TRENDS EARLIER IN
THE WEEK, WITH SEVERAL MACHINE-LEARNING MODELS IDENTIFYING A 15%-30%
PROBABILITY FOR SEVERE STORMS OVER OUR REGION BEFORE SHIFTING
TOWARDS THE SOUTH BY MONDAY. THAT BEING SAID, THE RECENT SHIFT IN
TRACK MEANS THAT THERE IS STILL SOME UNCERTAINTY IN THE OVERALL
SEVERE POTENTIAL; NONETHELESS, SOME SHOWERS AND THUNDERSTORMS CAN BE
ANTICIPATED AS THIS FRONTAL BOUNDARY PUSHES OFF THE EAST COAST EARLY
NEXT WEEK.
LINGERING SHOWERS & THUNDERSTORMS REMAIN POSSIBLE ON MONDAY AS THE
STEMMING COLD FRONT TRANSITIONS OFFSHORE TO THE SOUTH. UPPER-LEVEL
PATTERNS RETURN TO A MORE ZONAL FLOW AT THIS POINT, WITH SURFACE
HIGH PRESSURE MOVING INTO THE REGION BY MIDWEEK. HUMIDITY LIKELY
REMAINS ELEVATED BY THIS TIME AS A TROUGH BRINGS MOISTURE JUST NORTH
OF THE REGION. HOWEVER, CHANCES FOR SEVERE WEATHER DIMINISHES FOR A
BIT AS HIGH PRESSURE BUILDS OVER THE APPALACHIANS. TEMPERATURES
REMAIN SEASONABLE, WITH HIGHS IN THE UPPER 80S AND LOWER 90S EACH
DAY.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
A MIXTURE OF SHALLOW FAIR WEATHER CUMULUS AND HIGH CLOUDS SHOULD
MAINTAIN VFR CONDITIONS ACROSS THE REGION. WITH THE FRONTAL ZONE
WELL OFF TO THE SOUTH, LOCAL TAF SITES ARE SEEING MAINLY
NORTHWESTERLY WINDS TODAY, WITH OCCASIONAL GUSTS TO AROUND 15
TO 20 KNOTS. WILL MAINTAIN A PROB30 GROUP AT KCHO FROM 4-8 PM
FOR THUNDERSTORMS, BUT THIS IS LOOKING LESS LIKELY BASED ON
CURRENT VISIBLE SATELLITE IMAGERY.
WINDS TURN MORE NORTHEASTERLY ON FRIDAY WITH A BROADER COVERAGE
OF SHOWERS AND THUNDERSTORMS. A DECAYING MCS MAY BRING SOME
MORNING RESTRICTIONS TO KCHO, WITH AFTERNOON/EVENING ACTIVITY
POSSIBLY IMPACTING THE D.C. TERMINALS. THE UNCERTAINTY SEEMS TO
INCREASE WITH NORTHWARD EXTENT FROM THE FRONT. FRIDAY NIGHT
CARRIES WITH IT CONTINUED ONSHORE FLOW WHICH COULD FAVOR SOME
LOWER CEILINGS OVERNIGHT. HIGH PRESSURE BUILDS OVER QUEBEC INTO
NEW ENGLAND ON SATURDAY WHICH WILL SUPPORT A RETURN TO VFR
CONDITIONS. THIS COMES WITH PREVAILING EASTERLY FLOW.
LINGERING SHOWERS AND THUNDERSTORMS COULD ALLOW INTERMITTENT SUB-VFR
CONDITIONS TO LINGER INTO MONDAY. ONCE THE FRONT PASSES THROUGH BY
TUESDAY, VFR CONDITIONS ARE ANTICIPATED WITH SOUTHWEST WINDS
SHIFTING NORTHWEST BY TUESDAY.
MARINE
WHILE NORTHWESTERLY WINDS WERE SLIGHTLY ELEVATED EARLIER IN THE
DAY, THE OVERALL MAGNITUDE OF WIND HAS GRADUALLY COME DOWN.
WINDS EVENTUALLY TURN MORE NORTHEAST TO EASTERLY INTO FRIDAY
AND SATURDAY, WITH GUSTS LARGELY STAYING BELOW ADVISORY
THRESHOLDS. ANY HAZARDOUS MARINE CONDITIONS WOULD BE TIED TO
CONVECTION, WITH FRIDAY BRINGING THAT GREATEST THREAT,
ESPECIALLY FOR THE MORE SOUTHERN WATERS. BY SATURDAY, EXPECT A
MOSTLY DRY DAY WITH HIGH PRESSURE BUILDING TO THE NORTH. WINDS
EVENTUALLY SHIFT TO SOUTHEASTERLY LATE SATURDAY WITH GUSTS UP TO
AROUND 15 KNOTS.
WINDS COULD REMAIN ELEVATED OVER THE WATERS INTO MONDAY MORNING AS
THE FRONT PASSES OFFSHORE BEFORE DIMINISHING BY THE END OF THE DAY.
WINDS STAY BELOW SCA LEVELS THROUGH MIDWEEK, WITH SOUTHERLY WINDS
SHIFTING NORTHERLY BY TUESDAY.
TIDES/COASTAL FLOODING
WATER LEVELS WILL SLOWLY ELEVATE IN THE NEXT COUPLE OF DAYS.
THIS BRINGS A MORE SENSITIVE LOCATION LIKE ANNAPOLIS INTO ACTION
STAGE FOR THE FRIDAY MORNING HIGH TIDE. HOWEVER, THERE REMAINS
NO DISCERNIBLE THREAT FOR COASTAL FLOODING THIS WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...BRO/SRT
AVIATION...BRO/SRT
MARINE...BRO/SRT
TIDES/COASTAL FLOODING...LWX
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