589
FXUS61 KLWX 200102
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
902 PM EDT SAT JUL 19 2025
SYNOPSIS
SHOWER AND THUNDERSTORM CHANCES CONTINUE THROUGH THE
WEEKEND. A COLD FRONT FOLLOWS SUNDAY NIGHT. LESS HUMIDITY AND
DRIER CONDITIONS TO START NEXT 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 NEXT
WEEK.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
CONVECTIVE ACTIVITY CONTINUES TO MOVE ACROSS SOUTHERN MARYLAND.
THIS ACTIVITY WILL MOVE OFFSHORE OVER THE NEXT COUPLE HOURS.
OTHERWISE, A WARM/HUMID AIR MAINTAINS ITS PRESENCE INTO THE
OVERNIGHT HOURS. FORECAST LOW TEMPERATURES FALL INTO THE UPPER
60S TO MID 70S, LOCALLY DOWN INTO THE MID 60S ACROSS MOUNTAIN
LOCATIONS. GIVEN LIGHT WINDS AND A SATURATED BOUNDARY LAYER,
PATCHY FOG WILL AGAIN BE POSSIBLE, ESPECIALLY WEST OF I-95.
SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/
EXPECT SOME LINGERING PATCHY FOG ACROSS THE AREA, PARTICULARLY
ACROSS THE LOW-LYING RIVER AND MOUNTAIN VALLEYS. WITH THE MID-JULY
SOLAR INSOLATION ANGLE KICKING IN, ANY FOG SHOULD MIX OUT 2 TO 3
HOURS AFTER SUNRISE. FOR SUNDAY, A RESIDUAL SEVERE WEATHER RISK
LOOMS AHEAD OF THE NEXT COLD FRONT THAT ARRIVES LATER IN THE
EVENING/NIGHT. FORECAST MODELS FAVOR AN UPTICK IN TEMPERATURES
WITH AREA-WIDE HIGHS RISING BACK INTO THE LOW 90S. THIS
CONTRIBUTES TO INCREASING INSTABILITY LEVELS, COUPLED WITH AN
UPTICK IN VERTICAL SHEAR WITH THE APPROACH OF THE UPPER TROUGH.
HOWEVER, DESPITE THIS DECENT COMBINATION OF INSTABILITY/SHEAR,
THE 12Z SUITE OF HIGH-RESOLUTION MODELS ARE NOT VERY ENTHUSED AS
NOTED BY THE LACK OF MEMBERS IN THE 40 DBZ PAINTBALL PLOTS.
WITH THE SIGNAL REMAINING STRONG ENOUGH, THE STORM PREDICTION
CENTER HAS MAINTAINED A MARGINAL RISK ACROSS THE ENTIRE REGION.
A SEASONABLY STRONG COLD FRONT SWEEPS THROUGH THE AREA ON SUNDAY
NIGHT BEFORE FULLY CLEARING THE AREA BY EARLY MONDAY. HOWEVER,
THE FULL INFLUENCE OF THIS BOUNDARY DOES NOT REALLY KICK IN
UNTIL SUBSEQUENT DAYS. THUS, EXPECT LOW TEMPERATURES IN THE
UPPER 60S TO MID 70S ON SUNDAY NIGHT, WHILE LOW/MID 60S ARE MORE
COMMONPLACE WEST OF I-81.
BY MONDAY MORNING, THE COLD FRONT IS FORECAST TO BE CROSSING THE
VIRGINIA/NORTH CAROLINA BORDER. A SHIFT TO NORTHERLY WINDS
ENSUES AS A STRONG DOME OF CANADIAN HIGH PRESSURE CROSSES THE
ONTARIO/QUEBEC BORDER. A NOTABLE FALL IN TEMPERATURES AND DEW
POINTS OCCURS GIVEN THIS PATTERN CHANGE. ANY SHOWER CHANCES WILL
LIKELY BE RELEGATED TO THE POTOMAC HIGHLANDS BEFORE DIMINISHING
THROUGH THE EVENING HOURS. A COOL NIGHT LIES AHEAD WITH
WIDESPREAD LOW TEMPERATURES IN THE LOW/MID 60S. SOME POCKETS OF
MID/UPPER 50S ARE POSSIBLE ALONG THE ALLEGHENY FRONT.
LONG TERM /TUESDAY THROUGH SATURDAY/
A STRONG AREA OF HIGH PRESSURE WILL BUILD TO OUR NORTH ON TUESDAY.
NORTHERLY FLOW WILL ADVECT COOLER AND DRIER AIR INTO THE AREA,
LEADING TO BELOW NORMAL TEMPERATURES AND LESS HUMID CONDITIONS.
MOSTLY SUNNY SKIES ARE EXPECTED, WITH HIGHS IN THE LOW TO MID 80S
AND DEWPOINTS DROPPING INTO THE 50S AND LOWER 60S. SOME OF THE
COOLEST OVERNIGHT LOWS IN SOME TIME ARE EXPECTED TUESDAY NIGHT, WITH
MANY LOCATIONS DROPPING BACK INTO THE 50S AND LOWER 60S.
HIGH PRESSURE WILL SHIFT EASTWARD OFF THE NEW ENGLAND COASTLINE ON
WEDNESDAY. WINDS WILL GRADUALLY SHIFT FROM EASTERLY TO SOUTHERLY
OVER THE COURSE OF THE DAY, WHICH MAY LEAD TO A SLIGHT UPTICK IN
HUMIDITY, WITH DEWPOINTS CLIMBING BACK INTO THE LOWER 60S. SKIES
SHOULD REMAIN MOSTLY SUNNY, AND TEMPERATURES WILL REMAIN BELOW
NORMAL, WITH HIGHS IN THE LOW TO MID 80S.
HIGH PRESSURE WILL PROGRESS FURTHER OFFSHORE LATE IN THE WEEK AS
UPPER RIDGING BUILDS IN ALOFT FROM THE OHIO VALLEY. WINDS WILL
REMAIN SOUTHERLY AS THE THE HIGH SHIFTS FURTHER OFFSHORE, WHICH WILL
LEAD TO A RETURN OF THE HEAT AND HUMIDITY. DEWPOINTS WILL CLIMB
WELL INTO THE 60S ON THURSDAY, BEFORE RETURNING INTO THE 70S ON
FRIDAY. TEMPERATURES WILL BE ON THE INCREASE AS WELL, WITH HIGHS ON
THURSDAY IN THE LOW TO MID 90S, AND THEN MID TO POTENTIALLY EVEN
UPPER 90S BY FRIDAY. WITH THE UPPER RIDGE BUILDING IN FROM THE WEST,
SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO REMAIN LIMITED, OR
POTENTIALLY EVEN NON-EXISTENT ON THURSDAY. COVERAGE OF STORMS IS
EXPECTED TO REMAIN LOW ON FRIDAY AS WELL, BUT WITH LIKELY AT LEAST A
FEW STORMS AROUND AS THE UPPER LEVEL RIDGE STARTS TO WEAKEN SLIGHTLY.
AVIATION /01Z SUNDAY THROUGH THURSDAY/
CONVECTION WINDS DOWN ACROSS THE AREA TONIGHT WITH SOME PATCHY
FOG POSSIBLE, ESPECIALLY ACROSS KCHO AND KMRB.
SUNDAY'S CONVECTIVE THREATS APPEAR MORE UNCERTAIN, BUT OVERALL
PARAMETERS STILL SUPPORT SOME DEGREE OF CONCERN. HAVE PLAYED IT
MORE CONSERVATIVELY WITH JUST A PREVAILING -SHRA GROUP AT THE
D.C. AND BALTIMORE TERMINALS FROM 20-00Z SUNDAY. HOWEVER, COULD
EASILY SEE THIS UPGRADED TO -TSRA IN FUTURE TAF ISSUANCES.
FOR MONDAY, WINDS SHIFT TO NORTHERLY AS CANADIAN HIGH PRESSURE
BUILDS TO THE NORTH. THIS WILL SUPPORT VFR CONDITIONS WITH DRIER
WEATHER AHEAD.
VFR CONDITIONS ARE EXPECTED ON BOTH TUESDAY AND WEDNESDAY. WINDS
WILL BE OUT OF THE NORTH TO NORTHEAST ON TUESDAY AND START OUT
EASTERLY ON WEDNESDAY, BEFORE TURNING OUT OF THE SOUTH BY THE END OF
THE DAY.
MARINE
GRADIENTS REMAIN ON THE WEAK SIDE SO THERE ARE NO MARINE HAZARDS
TIED TO THE BACKGROUND WIND FIELDS. SMWS REMAIN IN EFFECT FOR
WIND GUSTS IN THUNDERSTORMS. RISK SHOULD LAST THROUGH THE LATER
HALF OF THE EVENING.
THE RISK FOR ADDITIONAL STORMS LOOMS ON SUNDAY AHEAD OF A MORE
FORMIDABLE COLD FRONT THAT TRACKS THROUGH LATE SUNDAY. THIS MAY
CAUSE SOME HAZARDOUS CONDITIONS FOR BOATERS, PARTICULARLY DURING
THE AFTERNOON AND EVENING HOURS. ADDITIONALLY, AN UPTICK IN
NORTHWEST TO NORTHERLY WINDS ON SUNDAY NIGHT INTO MONDAY
MORNING. SOME CHANNELING EFFECTS MAY FURTHER ENHANCE THESE
WINDS. SMALL CRAFT ADVISORIES MAY BE NEEDED DURING THIS PERIOD
OF UPTICK.
SUB-SCA LEVEL WINDS ARE EXPECTED ON BOTH TUESDAY AND WEDNESDAY.
WINDS WILL BE OUT OF THE NORTH TO NORTHEAST ON TUESDAY, AND
GRADUALLY TURN FROM OUT OF THE EAST TO OUT OF THE SOUTH OVER THE
COURSE OF THE DAY WEDNESDAY.
TIDES/COASTAL FLOODING
LIGHT WINDS ACROSS THE AREA WILL MAINTAIN ELEVATED TIDAL ANOMALIES.
AT THIS POINT, ONLY ANNAPOLIS COULD SEE A RUN AT MINOR TIDAL
FLOODING, MAINLY DURING THE HIGHER OF THE ASTRONOMICAL TIDES. THESE
WILL OCCUR DURING THE MIDDLE OF THE NIGHT THIS WEEKEND. A STRONG
COLD FRONT MOVES THROUGH THE WATERS LATE SUNDAY WHICH SHOULD HELP
LOWER WATER LEVELS INTO NEXT WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...BRO
NEAR TERM...BRO/CPB
SHORT TERM...BRO
LONG TERM...KJP
AVIATION...BRO/KJP/CPB
MARINE...BRO/KJP/CPB
TIDES/COASTAL FLOODING...LWX
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