904
FXUS61 KLWX 111907
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
307 PM EDT FRI JUL 11 2025
SYNOPSIS
A VERY WARM AND HUMID AIR MASS WILL PERSIST THROUGH MONDAY. A
WEAK FRONT WILL APPROACH THE AREA LATE MONDAY, THEN CROSS THE
AREA MONDAY NIGHT BEFORE STALLING AND DISSIPATING SOUTH OF THE
AREA TUESDAY.
NEAR TERM /THROUGH TONIGHT/
ISOLATED AIR MASS THUNDERSTORMS ARE ONGOING WEST OF THE BLUE
RIDGE DUE TO TERRAIN CIRCULATIONS AND ARE DRIFTING ESE. NUCAPS
DATA FROM 1749Z SHOWED 850 MB MOISTURE AND INSTABILITY AXIS
RUNNING FROM NEAR HAGERSTOWN SOUTH ALONG THE US-15 CORRIDOR INTO
ORANGE COUNTY. ANOTHER MAXIMA IN CAPE IS SEEN OVER WESTERN MD
WHERE SEVERAL CLUSTERS OF THUNDERSTORMS ARE ONGOING. A MINIMA
IN MOISTURE AND CAPE IS SEEN EAST OF I-83 AND I-95 AND THE
CENTRAL SHENANDOAH VALLEY.
CONVECTIVE ACTIVITY IS EXPECTED TO DWINDLE QUICKLY AFTER 01Z
WITH A WARM AND MUGGY NIGHT EXPECTED. EXPECT PATCY DENSE FOG IN
AREAS THAT GET RAIN AND RIVER VALLEY FOG.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
CONTINUED HEIGHT RISES SATURDAY SHOULD KEEP THUNDERSTORM
COVERAGE WIDELY SCATTERED TO SCATTERED AND DISORGANIZED, BUT
EXPECTING THE CVRG TO BE GREATER THAN TODAY DUE TO MORE
INSTABILITY AVAILABLE. DOWNBURSTS WILL BE THE PRIMARY THREAT DUE
TO LARGE AMOUNTS OF INSTABILITY.
WEAK HEIGHT FALLS FROM APPROACHING UPPER LEVEL TROUGH SHOULD
HELP BOOST THUNDERSTORM POTENTIAL SUNDAY. EXPECT SIGNIFICANTLY
GREATER COVERAGE AND SOME SEVERE AND/OR FLASH FLOODING
LONG TERM /MONDAY THROUGH FRIDAY/
HEADING INTO NEXT WEEK, THE NORTHERN BRANCH OF THE JET STREAM WILL
CONTINUE TO HAVE AREAS OF AMPLIFICATION THAT TRACK ACROSS THE
NORTHERN TIER OF THE U.S. ONE SUCH AREA IS EXPECTED TO PUSH ACROSS
THE NORTHEASTERN U.S. ON MONDAY WHICH HELPS DRAG A LOOSELY DEFINED
COLD FRONT TOWARD THE MID-ATLANTIC REGION. CONTINUED WARM AND HUMID
CONDITIONS AHEAD OF THIS BOUNDARY WILL CERTAINLY INCREASE THE
THUNDERSTORM RISK ON MONDAY AFTERNOON/EVENING. WITH CONVECTION
LIKELY THE PREVIOUS DAY, IT REMAINS TO BE SEEN HOW MUCH CONVECTIVE
DEBRIS LINGERS INTO MONDAY MORNING. AS INSTABILITY IS PREDICATED ON
DAYTIME HEATING, THIS IS AN IMPORTANT ASPECT OF THE FORECAST WHICH
IS NOT COMPLETELY KNOWN YET. HOWEVER, THERE IS CERTAINLY A DECENT
SIGNAL FOR AN ELEVATED THREAT OF SEVERE THUNDERSTORMS AND FLASH
FLOODING.
THE MENTIONED FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH LATE
MONDAY NIGHT BEFORE SETTLING JUST OFF TO THE SOUTH DURING SUBSEQUENT
DAYS. WITH THE SOUTHEASTERN U.S. MID/UPPER RIDGE FLEXING NORTHWARD
IN TIME, THIS BUILDING OF HEIGHTS MAY LEAD TO THIS BOUNDARY STALLING
NEARBY. AS SUCH, SHOWER AND THUNDERSTORM CHANCES ARE EXPECTED TO
INCREASE THROUGH THE WEEK, PARTICULARLY AS THE STALLED FRONT RETURNS
NORTHWARD AS A WARM FRONT ON WEDNESDAY. THIS COMES WITH CONTINUED
SUMMERTIME HEAT AND HUMIDITY AS HIGHS SOAR INTO THE LOW 90S. WHILE
ENSEMBLE BOX-AND-WHISKER PLOTS SHOW INCREASING TEMPERATURE SPREAD,
IT DOES SEEM LIKELY READINGS STAY FAIRLY CLOSE TO CLIMATOLOGY.
HEADING INTO THE END OF THE NEXT WORK WEEK, THE MID-ATLANTIC REGION
SHOULD REMAIN WELL ENTRENCHED IN THE WARM/MOIST SECTOR.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
CAN'T RULE OUT A THUNDERSTORM AT IAD LATER TODAY, BUT MOST
LIKELY WILL STAY DRY. CHO AND MRB WILL HAVE THE BEST CHANCE OF
THUNDERSTORMS TODAY. EXPECTING A BIT MORE THUNDERSTORM COVERAGE
SAT AND PARTICULARY SUNDAY. HAVE ADDED PROB30 GROUPS FOR
SATURDAY FOR ALL THE MAJOR AIRPORTS.
WITH A COLD FRONT APPROACHING FROM THE WEST ON MONDAY, THERE WILL BE
AN INCREASING RISK OF SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON
TO EVENING HOURS. WHILE CONDITIONS SHOULD BE VFR OUTSIDE OF SUCH
STORMS, RESTRICTIONS ARE LOOKING LIKELY WITH ANY CONVECTIVE
ACTIVITY. SOME DEGREE OF WIND SHIFT TAKES PLACE LATE MONDAY BEHIND
THE FRONT, BUT GRADIENTS REMAIN ON THE WEAK SIDE.
THIS FRONTAL ZONE STALLS JUST OFF TO THE SOUTH BEFORE RETURNING
NORTHWARD AS A WARM FRONT ON WEDNESDAY. ADDITIONAL ROUNDS OF STORMS
MAY LEAD TO AFTERNOON/EVENING RESTRICTIONS.
MARINE
EXCELLENT BOATING CONDITIONS OVER THE WEEKEND WITH LIGHT WINDS
AND THUNDERSTORM POTENTIAL MOST LIKELY STAYING AWAY FROM THE
WATERS. BETTER CHANCE FOR THUNDERSTORMS MONDAY.
OVERALL GRADIENTS REMAIN ON THE WEAKER SIDE WHICH SHOULD KEEP
BACKGROUND WIND GUSTS AT 10 KNOTS OR LESS ON MONDAY AND TUESDAY.
HOWEVER, AN APPROACHING COLD FRONT CROSSES THROUGH THE REGION LATE
MONDAY BEFORE STALLING OFF TO THE SOUTH ON TUESDAY. THE ASSOCIATED
AFTERNOON/EVENING THUNDERSTORMS COULD LEAD TO SOME HAZARDOUS MARINE
CONDITIONS. SOME OF THE STRONGER STORMS MAY REQUIRE SPECIAL MARINE
WARNINGS.
TIDES/COASTAL FLOODING
A PROLONGED PERIOD OF SOUTHERLY WINDS WILL LEAD TO ELEVATED
TIDAL ANOMALIES OVER THE WEEKEND. THIS CARRIES MOST OF THE TIDAL
LOCATIONS INTO ACTION STAGE, PARTICULARLY DURING THE HIGHER OF
THE TWO ASTRONOMICAL HIGH TIDE CYCLES. SENSITIVE LOCATIONS,
SUCH AS ANNAPOLIS, ARE FORECAST TO HIT MINOR STAGE DURING THE
HIGH TIDE CYCLE SUNDAY MORNING.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...BRO
AVIATION...LFR/BRO
MARINE...LFR/BRO
TIDES/COASTAL FLOODING...
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