457
FXUS61 KLWX 130124 AAA
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
924 PM EDT WED AUG 12 2026
WHAT HAS CHANGED
THUNDERSTORM RISK IS DIMINISHING TONIGHT.
KEY MESSAGES
- 1) DECREASING STORM COVERAGE TODAY BEFORE RAMPING UP LATE IN
THE WEEK WITH A RETURNING WARM FRONT.
- 2) SHOWERS AND THUNDERSTORMS POSSIBLE BETWEEN SUNDAY AND
MONDAY BEFORE BECOMING DRIER INTO EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...DECREASING STORM COVERAGE TODAY BEFORE RAMPING
UP LATE IN THE WEEK WITH A RETURNING WARM FRONT.
SCATTERED SHOWERS AND THUNDERSTORMS OVER CENTRAL PENNSYLVANIA
WILL TRACK SOUTHEAST AND LARGELY MISS OUR AREA TONIGHT, EXCEPT
PERHAPS CECIL COUNTY. OTHER SHOWERS TRIED TO FORM EARLIER OVER
SHENANDOAH COUNTY, BUT HAVE VANISHED. THERE IS A LOW-LEVEL
MOISTURE GRADIENT SEEN ON POLAR IMAGERY ROUGHLY ALONG RT 15 AND
THE 00Z IAD SOUNDING SHOWED 759 J/KG OF CAPE WITH LITTLE
INHIBITION. THERE IS A WEAK TROUGH THAT IS FCST TO CROSS THE
AREA BETWEEN NOW AND 06Z, SO THERE IS STILL A CHANCE SOME
SHOWERS OR STORMS MAY DEVELOP, BUT THE WINDOW IS CLOSING DOWN.
LIGHTNINGCAST V2 DOESN'T SHOW ANY DEVELOPMENT IMMINENT AT THIS
TIME. THE WINDOW FOR ANY DEVELOPMENT THIS EVENING IS VERY SHORT.
HEIGHTS FURTHER BUILD ON THURSDAY INTO FRIDAY AS UPPER RIDGING
STRETCHES UP FROM THE GULF OF AMERICA INTO THE CENTRAL AND
SOUTHEASTERN U.S. LOCALLY, BEING NORTH OF THIS RIDGE WILL FAVOR
CONTINUED NORTHWESTERLY FLOW ALOFT WHICH CARRIES THE RISK OF
MESOSCALE CONVECTIVE SYSTEMS (MCS) INTRUSIONS. ON THURSDAY, THE
MAIN SHOWER AND THUNDERSTORM CHANCES FOCUS ACROSS THE
ALLEGHENIES DOWN INTO THE CENTRAL VIRGINIA PIEDMONT AND I-64
CORRIDOR. THIS LARGELY TIES TO THE FRONT STILL BEING DISPLACED
OFF TOWARD THE SOUTH. EVENTUAL NORTHWARD PROGRESSION IS POSSIBLE
INTO FRIDAY WHICH INTRODUCES A BETTER CHANCE FOR STORMS. THE
LATEST ENSEMBLES SUPPORT PROBABILITIES IN THE 40 TO 70 PERCENT
RANGE. WHILE NOT A WASHOUT BY ANY MEANS, THIS SHOULD BE HEAVILY
GUIDED BY THE PEAK IN DAYTIME HEATING. HIGH TEMPERATURES EACH
DAY WILL BE IN THE 80S TO LOW 90S, WITH 70S FOR THE MOUNTAINS.
LIKEWISE, SEASONABLE CONDITIONS CAN BE EXPECTED OVERNIGHT.
AMPLE HIGH PRESSURE BUILDS TO THE NORTH OF THE REGION ON
SATURDAY AS THE FRONTAL ZONE AGAIN SAGS BACK TOWARD THE
CAROLINAS. AN ONSHORE COMPONENT TO THE WIND COULD KEEP SOME
ADDITIONAL CLOUD COVER AROUND. HOWEVER, OVERALL TRENDS SUGGEST A
DROP OFF IN HUMIDITY BEFORE WINDS RETURN TO SOUTHERLY LATE IN
THE WEEKEND.
KEY MESSAGE 2... SHOWERS AND THUNDERSTORMS POSSIBLE BETWEEN
SUNDAY AND MONDAY BEFORE BECOMING DRIER INTO EARLY NEXT WEEK.
UPPER-LEVEL RIDGING CONTINUES TO BUILD OVER THE SOUTHWEST CONUS OVER
THE WEEKEND, WITH MULTIPLE SHORTWAVE TROUGHS TRACKING TO THE EAST
OFFSHORE OF NEW ENGLAND. BEGINNING SUNDAY, AN UPPER-LEVEL
PERTURBATION FORMS OVER THE CANADIAN ROCKIES AND TRACKS EASTWARD,
WITH A STEMMING FRONTAL BOUNDARY TRACKING ACROSS THE EAST COAST LATE
SUNDAY AND INTO MONDAY. THIS BOUNDARY WILL LIKELY BRING CHANCES FOR
SCATTERED SHOWERS AND THUNDERSTORMS HERE IN THE MID-ATLANTIC,
ALTHOUGH MODEL GUIDANCE HAS BEEN SOMEWHAT MARGINAL ON THE SEVERE
POTENTIAL FOR THIS EVENT. AS OF THE 12Z ENSEMBLE RUNS, SEVERAL
OUTPUTS HAVE THE HIGHEST LIKELIHOOD FOR SEVERE WEATHER JUST SOUTH OF
THE AREA TOWARDS SOUTHERN VA AND THE CAROLINAS, WHILE THE GFS
ENSEMBLE RUNS STILL HAVE A 15%-30% PROBABILITY FOR SEVERE WEATHER
CENTERED WITHIN THE REGION. SHOULD ANY THUNDERSTORMS BECOME SEVERE,
THE MOST LIKELY HAZARDS WILL LIKELY BE ELEVATED WIND GUSTS AS WELL
AS LOCALLY HEAVY RAINFALL. AS DROUGHT CONDITIONS CONTINUE TO IMPROVE
WITHIN THE REGION, FLOODING POTENTIAL BECOMES MORE OF A CONCERN WITH
ANY HEAVY RAINFALL-PRODUCING THUNDERSTORMS THAT MATERIALIZE.
OTHERWISE, TEMPERATURES REMAIN NEAR-NORMAL FOR MID-AUGUST, WITH
HUMID CONDITIONS AS WELL AS TEMPERATURES RANGING IN THE 80S AND
LOWER-90S AT TIMES NEAR THE METROS. HIGH PRESSURE MOVES INTO THE
REGION ONCE THE FRONTAL BOUNDARY PASSES OFFSHORE BY TUESDAY,
BRINGING DRIER CONDITIONS TO THE REGION.
AVIATION /01Z THURSDAY THROUGH MONDAY/
WHILE VFR CONDITIONS ARE EXPECTED INTO THURSDAY, HAVE INTRODUCED
A PROB30 FOR THUNDERSTORM RESTRICTIONS LATE THIS EVENING.
OTHERWISE, WINDS REMAIN SOMEWHAT VARIABLE AND LIGHT GIVEN
CONTINUED WEAK GRADIENTS. WINDS ON THURSDAY SHOULD BE MAINLY OUT
OF THE WEST TO NORTHWEST WITH THE FRONTAL ZONE OFF TO THE SOUTH.
ANY AFTERNOON/EVENING STORMS SHOULD BE CONFINED CLOSER TO I-64
AROUND KCHO, WITH OTHERS TO THE NORTH REMAINING DRY. MORE
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON FRIDAY
WHICH WOULD FAVOR FURTHER CONVECTIVE-DRIVEN RESTRICTIONS. HIGH
PRESSURE BUILDS TO THE NORTH ON SATURDAY WHICH SHOULD FAVOR VFR
CONDITIONS AMIDST EAST TO NORTHEASTERLY WINDS.
BEGINNING SUNDAY, A COLD FRONT COULD BRING SUB-VFR CONDITIONS TO
TERMINALS AS SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THROUGHOUT THE REGION. THESE CONDITIONS COULD BE INTERMITTENT
THROUGH MONDAY AS THE FRONT PASSES THROUGH. SOUTHEAST WINDS SHIFT
NORTHWEST MONDAY EVENING IN THE WAKE OF THE FRONT.
MARINE
BACKGROUND WINDS REMAIN ON THE WEAKER SIDE AS A FRONTAL ZONE
SAGS OFF TOWARD THE SOUTH. GUSTS WILL MOSTLY BE IN THE 5 TO 10
KNOT RANGE, WHILE PUSHING UP TO 15 KNOTS AT TIMES WHEN SOUTHERLY
CHANNELING OCCURS. THE MAIN THREAT FOR HAZARDOUS MARINE
CONDITIONS WOULD BE ON FRIDAY GIVEN MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS. ANY STORM WILL BE CAPABLE OF GUSTY WINDS AND
FREQUENT LIGHTNING. THIS FRONT DROPS TOWARD THE CAROLINAS ON
SATURDAY AS HIGH PRESSURE BUILDS OVER THE NORTHEASTERN U.S. THE
RESULTING WINDS WILL MAINLY BE OUT OF THE EAST TO NORTHEAST.
SCAS WILL LIKELY BE NEEDED BY SUNDAY AFTERNOON AS A COLD FRONT
TRACKS THROUGH THE REGION. BETWEEN SUNDAY & MONDAY, GUSTY SHOWERS
AND THUNDERSTORMS ARE POSSIBLE OVER THE WATERS. WINDS DIMINISH ONCE
THE FRONT PASSES THROUGH LATE MONDAY. SOUTHEAST WINDS SHIFT
NORTHWEST BY MONDAY EVENING IN THE WAKE OF THE FRONT.
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 THURSDAY MORNING HIGH TIDE. HOWEVER, THERE IS
CURRENTLY NO DISCERNIBLE THREAT FOR COASTAL FLOODING THIS WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...LFR/BRO/SRT
AVIATION...LFR/BRO/SRT
MARINE...LFR/BRO/SRT
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