502
FXUS61 KLWX 201933
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
333 PM EDT SUN JUL 20 2025
SYNOPSIS
A COLD FRONT MOVES THROUGH THE AREA TONIGHT. LESS HUMIDITY AND
DRIER CONDITIONS TO START THE WORK WEEK AS CANADIAN HIGH
PRESSURE BUILDS IN TO THE NORTH. AS THIS RIDGE OF HIGH PRESSURE
MOVES INTO THE CANADIAN MARITIMES, HEAT AND HUMIDITY RETURN LATE
IN THE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
ISOLATED TO SCATTERED LIGHT SHOWERS WILL REMAIN POSSIBLE FOR
AREAS EAST OF ROUTE 15 UNTIL 6 OR 7 PM THIS EVENING, MAINLY
ACROSS NORTH CENTRAL AND NORTHEAST MD AS BROAD TROUGHING
DEVELOPS.
THIS EVENING...SHOWERS AND THUNDERSTORMS OVER SOUTHERN OHIO AND
WV WILL CROSS THE APPALACHIANS AND SHOULD ARRIVE IN A WEAKENED
STAGE BEFORE DISSIPATING OVERNIGHT. A COLD FRONT WILL CROSS THE
AREA OVERNIGHT WITH DRIER AIR FILTERING IN ON NORTH WINDS.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
COLD FRONT WILL CONTINUE TO PUSH SOUTH OF THE AREA MONDAY
AFTERNOON. THERE COULD STILL BE ENOUGH MOISTURE AND INSTABILITY
ALONG AND SOUTH OF I-64 IN CENTRAL VA FOR AN ISOLATED SHOWER OR
THUNDERSTORM TO DEVELOP BEFORE SUFFICIENT DRY AIR INHIBITS ANY
CONVECTIVE DEVELOPMENT. WARM, BUT NOTICEABLE LESS HUMID ON LIGHT
N BREEZES. TEMPS DROP INTO THE 60S MON NIGHT FOR THE FIRST TIME
SINCE EARLY IN THE MONTH.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
A LARGE UPPER RIDGE INITIALLY ACROSS THE GULF COAST UP TO THE
TENNESSEE/OHIO VALLEY IS EXPECTED TO BUILD NORTH AND EAST ON
WEDNESDAY AND THURSDAY. AS THIS OCCURS, STRONG SUBSIDENCE UNDERNEATH
THIS ANTICYCLONE CENTER WILL KEEP CONDITIONS DRY OVER THE REGION.
MOISTURE RETURN IS EXPECTED TO SLOWLY INCREASE THROUGH THE WEEK AS
HIGH PRESSURE ALONG THE EASTERN SEABOARD WEAKENS. BY THURSDAY, THIS
HELPS USHERS DEW POINTS BACK INTO THE LOW 70S. WHILE SOME EROSION OF
THE NORTHERN EXTENT OF THIS RIDGE OCCURS, EXPECT ABOVE AVERAGE
TEMPERATURES TO RETURN TO THE PICTURE FOR FRIDAY ONWARD. THE GLOBAL
MODEL CONSENSUS SUPPORTS MID/UPPER 90S TEMPERATURES ON FRIDAY, WHILE
LIKELY CONTINUING INTO SATURDAY. ADDING THE INCREASE IN HUMIDITY
LEVELS SHOULD ALLOW HEAT INDICES TO PUSH BACK INTO THE 100 TO 105
DEGREE RANGE. THUS, SOME SPOTS COULD NEAR OR REACH ADVISORY LEVEL
HEAT BOTH DAYS. GIVEN THIS IS STILL 5 TO 6 DAYS AWAY, DETAILS LIKE
CLOUD COVER, WIND SPEED/DIRECTION, AND INFLUENCE OF SHOWERS COULD
LEAD TO MORE PREDICTABILITY THAN GLOBAL ENSEMBLES SUGGEST.
THE GUIDANCE FURTHER INCREASE CONVECTIVE CHANCES NEXT WEEKEND AS A
SLOW MOVING FRONTAL BOUNDARY APPROACHES FROM THE WEST. GIVEN NEAR
NEUTRAL HEIGHT CHANGES, THERE IS SOME POTENTIAL FOR THIS BOUNDARY TO
STALL NEARBY. ENSEMBLE SPREAD INCREASES FURTHER GIVEN UNKNOWNS ABOUT
THE POSITION OF THIS FRONTAL SYSTEM.
AVIATION /19Z SUNDAY THROUGH FRIDAY/
ISOLD TO SCATTERED SHOWERS ARE EXPECTED INTO EARLY THIS EVENING.
THEN, WINDS WILL SHIFT FROM NW TO N AFTER FRONTAL PASSAGE. QUIET
MON AND TUE.
VFR CONDITIONS ARE EXPECTED ON WEDNESDAY AND THURSDAY AS THE AREA
FEELS THE INFLUENCE OF AN EXPANDING RIDGE OVER THE SOUTHERN U.S. ANY
SHOWER CHANCES WAIT UNTIL FRIDAY, ALBEIT WITH CHANCES AROUND 15 TO
25 PERCENT. AT THIS POINT, ANY THREAT FOR RESTRICTIONS SHOULD AWAIT
FOR NEXT WEEKEND. INITIAL WINDS WILL BE OUT OF THE SOUTH TO
SOUTHEASTERLY BEFORE SHIFTING TO SOUTHWESTERLY BY FRIDAY.
MARINE
ISOLATED BRIEF GUSTS TO 20 KT ARE POSSIBLE THIS AFTERNOON. THEN,
MORE STEADY 20 KT GUSTS ARE EXPECTED LATE THIS EVENING AND
OVERNIGHT AS WINDS TURN NORTHERLY BEHIND A COLD FRONG AND
CHANNELING INCREASES.
GRADIENTS REMAIN ON THE WEAKER SIDE WHICH SHOULD KEEP WINDS BELOW
ADVISORY THRESHOLDS. AS WINDS SHIFT TO SOUTHERLY ON THURSDAY, SOME
CHANNELING EFFECTS ARE POSSIBLE DURING THE EVENING INTO THE
OVERNIGHT HOURS. ANY CONVECTIVE CHANCES ARE VERY LOW UNTIL
CONDITIONS TURN MORE ACTIVE INTO NEXT WEEKEND.
TIDES/COASTAL FLOODING
WATER LEVELS ARE EXPECTED TO DROP THROUGH MONDAY AS NW TO N
WINDS STRENGTHEN WITH A FRONTAL PASSAGE. BY THE MIDDLE OF THE
WEEK, WATER LEVELS ARE EXPECTED TO RISE AGAIN ON STRENGTHENING
SSE WINDS. FOLLOWED ESTOFS GUIDANCE WHICH HAS PERFORMED THE BEST
ON SOUTHERLY FLOW REGIMES THIS SUMMER.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EDT
MONDAY FOR MDZ008.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EDT
MONDAY FOR ANZ530>534-537-539>541-543.
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR/KRR
LONG TERM...BRO
AVIATION...LFR/BRO
MARINE...LFR/BRO
TIDES/COASTAL FLOODING...
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page