551
FXUS61 KLWX 210603
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
203 AM EDT MON JUL 21 2025
SYNOPSIS
LOWER RAIN CHANCES AND LOWER HUMIDITY TODAY THROUGH THE MIDDLE OF
NEXT WEEK AS A STRONG AREA OF CANADIAN HIGH PRESSURE BUILDS TO THE
NORTH. A RETURN TO MORE SUMMERTIME CONDITIONS IS EXPECTED BY LATE
THIS WEEK.
NEAR TERM /THROUGH TONIGHT/
A COLD FRONT IS CURRENTLY TRACKING SOUTH THROUGH THE AREA EARLY THIS
MORNING. SHOWERS ALONG THE FRONT WILL BRING BRIEF PERIOD OF LIGHT TO
MODERATE RAIN FOR THOSE IN NORTHERN VA AND THE SHENANDOAH VALLEY,
WITH SPRINKLES ELSEWHERE. THE FRONT WILL MAKE GOOD PROGRESS EAST OF
THE BLUE RIDGE, PUSHING SOUTH OF I-66 BY SUNRISE. THE WESTERN HALF
OF THE FRONT WILL BE SLOWER TO CROSS THE CENTRAL APPALACHIANS AND
CENTRAL SHENANDOAH VALLEY THROUGH THIS AFTERNOON. THIS COULD PRODUCE
ANOTHER ROUND OF SHOWERS AND A FEW THUNDERSTORMS LATE THIS MORNING
THROUGH MID AFTERNOON. ELSEWHERE, DRY CONDITIONS ARE EXPECTED TODAY.
SEASONABLE TEMPERATURES AS HIGHS REACH THE LOW TO MID 80S THIS
AFTERNOON, WITH MUCH LESS HUMIDITY IN PLACE. A REINFORCING FRONT
MOVES THROUGH THIS EVENING AND SWEEPS OUT ANY REMAINING SHOWERS IN
CENTRAL VA. TONIGHT IS LIKELY TO BE THE FIRST "COOL" SUMMER NIGHT IN
A WHILE AS LOWS DROP TO THE 60S, WITH UPPER 50S IN THE MOUNTAINS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
CANADIAN HIGH PRESSURE DOMINATES ACROSS THE REGION THROUGH MID WEEK.
DRY AND SEASONAL CONDITIONS PREVAIL. HIGHS IN THE 80S EACH DAY AND
OVERNIGHT LOWS SETTLE IN THE 60S. NORTHEAST TO EAST WINDS ON TUESDAY
SHIFT TO SOUTHEAST ON WEDNESDAY AS THE HIGH SLIDES OFFSHORE. MID-
LEVEL RIDGING STARTS TO BUILD INTO THE AREA FROM THE WEST ON
WEDNESDAY, BUT WE WON'T SEE ANY SIGNIFICANT TEMPERATURE INCREASES
UNTIL LATE IN THE WEEK.
LONG TERM /THURSDAY THROUGH SUNDAY/
A PERSISTENT UPPER-LEVEL RIDGE REMAINS STUCK OVERHEAD THURSDAY WHILE
SURFACE HIGH PRESSURE SHIFTS OFFSHORE. THIS WILL BRING A RETURN TO
VERY WARM AND HUMID CONDITIONS TO THE REGION. HOWEVER, THUNDERSTORM
CHANCE WILL REMAIN VERY LOW ANYWHERE IN THE FORECAST AREA. EXPECT
HIGHS IN THE MID TO UPPER 80S, WITH DEWPOINTS CLIMBING BACK INTO THE
UPPER 60S TO LOW 70S.
THE UPPER-LEVEL RIDGE FINALLY BEGINS TO BREAK DOWN OVERHEAD WHILE A
WEAK COLD FRONT DROPS SOUTH ACROSS THE REGION. AT THIS TIME, THIS
LOOKS TO BRING THUNDERSTORMS POTENTIALLY FOR AREAS WEST OF THE BLUE
RIDGE. WE WILL SEE HOW THE PLACEMENT OF THE RIDGE WORKS OUT, BUT
STORMS FRIDAY MAY REALLY STRUGGLE TO DO MUCH WITH SUBSIDENCE ALOFT
STILL IN PLAY. HOWEVER, IT WILL BE MUCH HOTTER, WITH HIGHS REACHING
THE MID 90S. THIS WILL BE PAIRED WITH DEW POINT WELL INTO THE 70S.
WOULD BE CONCERNED FOR POTENTIAL HEAT HEADLINES ON FRIDAY FOR SURE,
SO THAT WILL BE SOMETHING TO KEEP IN MIND.
BY THE WEEKEND, A MORE ACTIVE UPPER-LEVEL PATTERN BEGINS TO SET UP,
AS A TROUGH BEGINS TO SETTLE OVER THE NORTHEAST CONUS. THIS WILL PUT
OUR REGION RIGHT IN LINE FOR SEVERAL SHORTWAVE TO ROUND THE BOTTOM
OF THE TROUGH INTO OUR REGION, AMIDST A CONTINUED HOT/HUMID AIR
MASS. BOTH SATURDAY AND SUNDAY POSE A THREAT FOR HEAT HEADLINES,
ESPECIALLY SATURDAY. ADDITIONALLY, BOTH DAYS WILL ALSO BRING THE
THREAT FOR SOME SEVERE THUNDERSTORMS AND VERY HEAVY RAINFALL. TOO
EARLY FOR EXACT DETAILS AT THIS TIME, BUT THINK THIS COULD BE
SOMETHING TO KEEP AN EYE ON OVER THE COMING DAYS.
AVIATION /06Z MONDAY THROUGH FRIDAY/
A COLD FRONT MOVES THROUGH THE AREA THIS MORNING, THOUGH PART OF IT
SLOWS AROUND CENTRAL VA. THIS COULD BRING SHOWERS TO CHO THIS
AFTERNOON, WITH DRY CONDITIONS ELSEWHERE. VFR CONDITIONS ARE
EXPECTED TO PREVAIL TODAY THROUGH MID WEEK AS HIGH PRESSURE BUILDS
IN FROM THE NORTH.
HIGH PRESSURE REMAINS OVERHEAD ON THURSDAY, LEADING TO CONTINUED VFR
CONDITIONS. AS THIS HIGH SHIFTS OFFSHORE LATE THURSDAY INTO FRIDAY,
HEAT AND HUMIDITY INCREASE, THUS INCREASING THE CHANCE FOR
THUNDERSTORMS. THIS WILL MAINLY BE WEST OF THE BLUE RIDGE HOWEVER,
SO BEST CHANCE AT MRB, WITH SMALLER CHANCES THAT RESIDUAL
SHOWERS/STORMS MAKE IT TO CHO/IAD LATE FRIDAY AFTERNOON. CHANCES
REMAIN AOB 30 PERCENT (HIGHEST WEST, CLOSER TO 15-20 PERCENT
EAST).
MARINE
NORTHERLY CHANNELING BEHIND A COLD FRONT MOVING THROUGH THE REGION
EARLY THIS MORNING WILL PRODUCE SCA CONDITIONS OVER MOST OF THE
WATERS. WINDS ARE FORECAST TO DIMINISH BY LATE MORNING, THEN FALL
BELOW SCA LEVELS THIS AFTERNOON AND EVENING.
ANOTHER BRIEF INCREASE IN WINDS IS POSSIBLE LATE TONIGHT, AND THESE
WINDS COULD BE CLOSE TO SCA LEVELS. THERE IS CURRENTLY NO SMALL
CRAFT ADVISORY IN EFFECT FOR TONIGHT DUE TO LOW CONFIDENCE, BUT
CONDITIONS WILL BE MONITORED AS NEW MODEL GUIDANCE COMES IN.
FAVORABLE MARINE CONDITIONS EXPECTED TUESDAY AND WEDNESDAY AS HIGH
PRESSURE DOMINATES ACROSS THE REGION.
BY THURSDAY, WINDS PICK UP A FEW KNOTS AND TURN SOUTHERLY. SUB-SCA
WINDS EXPECTED DURING THE DAY, BUT COULD SEE SOUTHERLY CHANNELING
DURING THE EVENING HOURS THAT COULD APPROACH SCA CRITERIA. WINDS
THEN TURN A BIT MORE SSW ON FRIDAY INTO FRIDAY EVENING, SO SUB-SCA
WINDS SHOULD PERSIST DURING THIS PERIOD. CAN'T COMPLETELY RULE OUT
SOME ROGUE NEAR-SCA GUSTS, BUT IT DOESN'T APPEAR QUITE AS LIKELY
FRIDAY EVENING.
TIDES/COASTAL FLOODING
WATER LEVELS ARE DROP TODAY AS NORTH WINDS STRENGTHEN BEHIND A COLD
FRONT THAT IS CROSSING THE AREA EARLY THIS MORNING. BY THE MIDDLE OF
THE WEEK, WATER LEVELS ARE EXPECTED TO RISE AGAIN ON STRENGTHENING
SOUTHEAST WINDS. SNAPBACK TIDE COULD PUSH WATER LEVELS INTO MINOR
FLOOD STAGE AT SOME SENSITIVE LOCATIONS (MAINLY ANNAPOLIS) BY THE
MIDDLE OF THE WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR MDZ008.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ530>534-537-
539>541-543.
SYNOPSIS...KRR
NEAR TERM...KRR
SHORT TERM...KRR
LONG TERM...CJL
AVIATION...KRR/CJL
MARINE...KRR/CJL
TIDES/COASTAL FLOODING...KRR
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