704
FXUS61 KLWX 170755
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
355 AM EDT SUN AUG 17 2025
SYNOPSIS
A WEAK AREA OF HIGH PRESSURE WILL GRADUALLY TRACK OFFSHORE TODAY.
A COLD FRONT APPROACHES FROM THE GREAT LAKES AND OHIO RIVER
VALLEY BEFORE CROSSING THROUGH THE AREA THIS EVENING INTO THE
OVERNIGHT HOURS. THIS FRONT WILL BRING INCREASED SHOWER AND
THUNDERSTORM CHANCES ALONG WITH COOLER TEMPERATURES TO THE
REGION AS THE BOUNDARY SAGS OFF TO THE SOUTH. THIS FRONTAL
SYSTEM REMAINS SOUTH OF THE REGION THROUGH MID-WEEK BEFORE
PULLING AWAY TOWARD THE COASTAL CAROLINAS BY LATE IN THE WEEK.
CANADIAN HIGH PRESSURE RETURNS FROM THE NORTH BY LATE WEEK INTO
NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
CURRENT OVERNIGHT CONDITIONS ARE FAIRLY TRANQUIL WITH SOME PASSING
MID-LEVEL CLOUDS OVERHEAD. OVER THE PAST 24 HOURS, DEW POINTS
HAVE DROPPED OFF BY A FEW DEGREES WHICH KEEPS READINGS IN THE
UPPER 60S TO LOW 70S. WINDS DO REMAIN SLIGHTLY ELEVATED WITH
SOUTH TO SOUTHWESTERLY WINDS AROUND 4 TO 8 MPH. SUCH WINDS HAVE
LARGELY OFFSET ANY DISCERNIBLE FOG PRODUCTION. HOWEVER, FOR
AREAS THAT DO FULLY DECOUPLE AND ATTAIN LIGHT WINDS, SOME PATCHY
RIVER/MOUNTAIN VALLEY FOG REMAINS POSSIBLE THROUGH AROUND 9 AM.
TODAY WILL OFFER THE WARMEST DAY OF THE PERIOD AS DAYTIME
HEATING IS AIDED BY A WESTERLY DOWNSLOPING FLOW REGIME. AS A
BROAD ANTICYCLONE STRENGTHENS ACROSS THE ARKLATEX UP TO THE
MISSOURI VALLEY, A CONVECTIVE COMPLEX LIKELY EMERGES OUT OF THE
LOWER GREAT LAKES AND OHIO VALLEY. THIS IS ALL IN RESPONSE TO A
COLD FRONT SLATED TO EDGE SOUTHEASTWARD THROUGH THE DAY.
IN ADVANCE OF THIS FRONTAL SYSTEM/CONVECTIVE LINE, AMPLE
HEATING IS EXPECTED TO TAKE PLACE. MANY LOCATIONS SHOULD SEE
HIGH TEMPERATURES RISE INTO THE LOW 90S. GIVEN 850-MB
TEMPERATURES SHOULD REACH THE 18-19C RANGE, A FEW 95 DEGREE
READINGS ALSO APPEAR POSSIBLE. THE QUESTION MARK WILL BE HOW
LONG ENHANCED LOW-LEVEL MOISTURE CAN REMAIN IN PLACE. INCREASED
BOUNDARY LAYER MIXING COULD EASILY NUDGE DEW POINTS DOWN BY A
FEW DEGREES WHICH WOULD SUPPORT DEW POINTS IN THE MID/UPPER 60S.
AT THIS POINT, HEAT INDICES NEAR THE CENTURY MARK ARE POSSIBLE,
BUT READINGS SHOULD FALL BELOW HEAT ADVISORY THRESHOLDS.
DURING THE AFTERNOON/EVENING HOURS, SKIES ARE LIKELY TO CLOUD UP
FROM NORTHWEST TO SOUTHEAST IN RESPONSE TO CONVECTION AND THE
ASSOCIATED CIRRUS ANVIL PLUMES. HIGH-RESOLUTION MODELS SUPPORT A
BROKEN LINE OF CONVECTION THAT TRACKS IN FROM THE NORTH. AIDED
BY STEEP LOW-LEVEL LAPSE RATES (8-9 C/KM), CONVECTIVE DOWNDRAFTS
COULD ATTAIN SOME FURTHER DOWNWARD MOMENTUM TRANSFER. THIS WILL
POSE A RISK OF DAMAGING WIND GUSTS WHICH IS SUPPORTED BY THE
MARGINAL RISK SHOWN BY THE STORM PREDICTION CENTER. THE CURRENT
OUTLOOK STRETCHES FROM THE EASTERN WEST VIRGINIA PANHANDLE DOWN
TO THE CENTRAL VIRGINIA PIEDMONT AND POINTS EASTWARD. ANY
CONVECTIVE THREAT LIKELY TAPERS OFF BY THE MID-EVENING AS
DECAYING ACTIVITY SLIDES TOWARD FAR SOUTHERN MARYLAND.
AS THE FRONTAL ZONE SLOWLY SAGS SOUTH OF THE AREA, SOME PATCHY
FOG IS POSSIBLE TONIGHT FROM I-81 WESTWARD. OVERNIGHT LOW
TEMPERATURES ARE FORECAST TO DROP INTO THE MID 60S TO LOW 70S,
SLIGHTLY COOLER IN THE HIGHER TERRAIN.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
A RECENT TREND IN THE GUIDANCE FAVORS KEEPING THE FRONTAL ZONE
SOUTH OF THE AREA THROUGH MID-WEEK. THIS ULTIMATELY FAVORS A
COOLER TEMPERATURE FORECAST RELATIVE TO PREVIOUS MODEL CYCLES.
FOR MONDAY, A NOTABLE NORTH-SOUTH ORIENTED THERMAL GRADIENT
EMERGES AS HIGHS NORTH OF U.S. 50 STAY IN THE MID/UPPER 70S.
OFF TO THE SOUTH, LOW/MID 80S ARE EXPECTED, PARTICULARLY CLOSER
TO THE I-64 CORRIDOR. BEING NORTH OF THE BOUNDARY, A STEADY
NORTHEASTERLY WIND IS EXPECTED WITH GUSTS UP TO 15 TO 20 MPH.
THIS WILL AID IN ENHANCED CLOUD COVER OVERSPREADING THE ENTIRE
REGION. SOME LIGHT OVERRUNNING SHOWER ACTIVITY IS POSSIBLE AT
ITMES, WITH ANY THREAT FOR THUNDERSTORMS LIKELY BEING TIED TO
AREAS THAT SEE SUNSHINE. WILL MAINTAIN CLOUDS AND SHOWER CHANCES
INTO MONDAY NIGHT AS MOISTURE CONTINUES TO OVERRUN THE BOUNDARY.
OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO THE 60S, WITH SPOTTY
70 DEGREE READINGS INSIDE D.C. AND BALTIMORE.
WHILE TUESDAY'S TEMPERATURE FORECAST HAS TRENDED DOWNWARD,
MULTI-ENSEMBLE BOX-AND-WHISKER PLOTS SHOW QUITE A BIT OF SPREAD.
THUS, THERE APPEARS TO BE SOME ENSEMBLE SOLUTIONS THAT EITHER
KEEP THE AREA DRIER OR MAINTAIN THE FRONT CLOSER TO U.S. 50. THE
CURRENT FORECAST PACKAGE FAVORS THE COOLER SCENARIO WHICH IS
COMPRISED OF PREVAILING EASTERLY WINDS. FORECAST HIGHS WOULD BE
IN THE MID/UPPER 70S FOR MOST LOCATIONS. HIGHER ELEVATIONS CAN
EXPECT READINGS IN THE UPPER 60S TO MID 70S. UNLIKE MONDAY WHERE
FORCING IS MORE NEBULOUS, GLOBAL MODELS SHOW SOME LOWERING OF
HEIGHTS APPROACHING FROM THE OHIO VALLEY. THIS WOULD AT LEAST
ENCOURAGE SOME ADDITIONAL SHOWER ACTIVITY AS MID/UPPER
ENERGETICS INTERACT WITH THE STALLED FRONTAL ZONE TO THE SOUTH.
ONSHORE FLOW CONTINUES INTO THE NIGHT WHICH SHOULD KEEP PLENTY
OF CLOUDS AROUND INTO TUESDAY NIGHT. FORECAST LOWS REMAIN
SIMILAR TO THE PRECEDING NIGHT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE CURRENT NHC TRACK HAS HURRICANE ERIN RECURVING BETWEEN THE
EASTERN SEABOARD AND BERMUDA DURING THE MID TO LATE PART OF THE
UPCOMING WEEK. WEDNESDAY LOOKS TO BE THE MOST ACTIVE CONVECTIVE DAY
FOR THE SECOND HALF OF THE WEEK AS THE HURRICANE'S INFLUENCE STILL
HAS NOT REACHED THE REGION. A PROGRESSIVE SHORTWAVE TROUGH IS
FORECAST TO TRACK OVER THE AREA, BRINGING AT LEAST SCATTERED
AFTERNOON TO EVENING THUNDERSTORMS. AFTERNOON TEMPS ON WEDNESDAY
REACH THE LOW TO MID 80S.
SUBSIDENCE ON HURRICANE ERIN'S WESTERN PERIPHERY WILL BRING LOWER
RAIN CHANCES TO OUR AREA FOR THURSDAY AND FRIDAY. THE LONG FETCH OF
NORTHEASTERLY WINDS PUSHES IN A COOLER MARINE AIRMASS WELL INTO THE
MID-ATLANTIC. THIS KEEP HIGHS ONLY IN UPPER 70S TO LOW 80S THURSDAY,
WITH PASSING SHOWERS AND ABUNDANT CLOUD COVER. SIMILAR CONDITIONS
ARE FORECAST FOR FRIDAY AS THE HURRICANE (PER NHC TRACK) IS FORECAST
TO QUICKLY PULL AWAY FROM THE U.S. COASTLINE.
IN WAKE OF ERIN, A SURFACE HIGH PRESSURE QUICKLY MOVES OVER THE AREA
INTO THE WESTERN ATLANTIC FRIDAY NIGHT INTO SATURDAY. THE RETURN OF
MOIST SOUTHERLY FLOW BRINGS HIGHER RAIN CHANCES AND WARMER
TEMPERATURES FOR THE START OF NEXT WEEKEND.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
VFR CONDITIONS REMAIN ACROSS ALL TERMINALS EARLY THIS MORNING.
GIVEN SLIGHTLY ELEVATED SOUTHERLY WINDS, THE THREAT FOR PATCHY
FOG/MIST HAS NOT UNFOLDED YET ACROSS KMRB AND KCHO. WINDS
GENERALLY RANGE FROM SOUTHWEST TO WESTERLY TODAY AHEAD OF THE
NEXT COLD FRONT. THIS FRONTAL SYSTEM CARRIES A BROKEN LINE OF
SHOWERS AND THUNDERSTORMS THAT MOVES THROUGH DURING THE
EARLY/MID EVENING HOURS. SOME RESTRICTIONS ARE POSSIBLE AS THIS
OCCURS, BUT THERE IS STILL PLENTY OF UNCERTAINTY. AS SUCH, WILL
MAINTAIN PROB30 GROUPS IN THE GENERAL 21Z-02Z WINDOW (EARLIER
FOR KMRB). BEHIND THE CONVECTION, SOME PATCHY FOG IS POSSIBLE
TONIGHT ACROSS THE WESTERN TERMINALS.
THE FRONTAL ZONE REMAINS SOUTH OF THE REGION ON MONDAY AND
TUESDAY. THIS MAINTAINS A LENGTHY PERIOD OF ONSHORE FLOW AND
PLENTY OF CLOUD COVER. NORTHEASTERLY WINDS ARE EXPECTED ON
MONDAY WITH GUSTS UP TO 15 TO 20 KNOTS. THESE WINDS SHIFT TO
EASTERLY BY TUESDAY. LOW CEILINGS ARE POSSIBLE DURING EACH
OVERNIGHT PERIOD. DURING THE DAYTIME, PASSING SHOWERS WILL ALSO
INTRODUCE SOME CHANCE FOR RESTRICTIONS AT TIMES.
SUB-VFR CONDITIONS ARE POSSIBLE AT TIMES WEDNESDAY AND THURSDAY
DUE TO LOW CLOUDS MOVING OVER THE AREA. NORTHEAST TO NORTH
WINDS COULD BE GUSTY AT TIMES AS HURRICANE ERIN MAKES ITS
CLOSEST APPROACH TO THE REGION.
MARINE
EARLY THIS MORNING, SLIGHTLY ELEVATED SOUTHERLY WINDS CONTINUE
ACROSS WIDER PORTIONS OF THE CHESAPEAKE BAY. SOUTHERLY
CHANNELING EFFECTS CONTINUE TO MAINTAIN GUSTS TO AROUND 15
KNOTS. OTHERWISE, MAXIMUM WIND GUSTS OUTSIDE OF CONVECTION TODAY
SHOULD BE AROUND 10 TO 15 KNOTS. A BROKEN LINE OF SHOWERS AND
THUNDERSTORMS TRACK ACROSS THE WATERS THIS EVENING. A FEW
SPECIAL MARINE WARNINGS ARE POSSIBLE FOR ANY OF THE STRONGER
UPDRAFTS. BEHIND THE FRONTAL ZONE RESPONSIBLE FOR THESE STORMS,
WINDS TURN MORE NORTHERLY LATE TONIGHT INTO MONDAY MORNING.
WINDS SHIFT TO NORTHEASTERLY MIDDAY MONDAY WITH GUSTS INCREASING
TO 15 TO 20 KNOTS FOR THE SECOND HALF OF THE DAY. THIS PATTERN
HOLDS IN PLACE INTO TUESDAY MORNING. SMALL CRAFT ADVISORIES WILL
LIKELY BE NEEDED DURING THIS UPTICK IN NORTHEASTERLY FLOW. WINDS
SHIFT TO EASTERLY ON TUESDAY WITH GUSTS TO AROUND 15 KNOTS,
PERHAPS SLIGHTLY HIGHER AT TIMES. SOME SHOWERS ARE POSSIBLE EACH
DAY AS MOISTURE OVERRUNS THE FRONTAL ZONE TO THE SOUTH.
SCA CONDITIONS ARE LIKELY AT SOME POINT WEDNESDAY AFTERNOON INTO
THURSDAY EVENING AS HURRICANE ERIN MAKES ITS CLOSEST APPROACH TO THE
REGION. NORTH TO NORTHEAST WINDS COULD GUST AROUND 20-25 KNOTS
DURING THIS TIME. ELEVATED WINDS AROUND SCA LEVELS COULD LINGER INTO
FRIDAY, THEN DIMINISH FOR NEXT WEEKEND.
TIDES/COASTAL FLOODING
ELEVATED TIDAL ANOMALIES CONTINUE THROUGH THE REMAINDER OF THE
WEEKEND WITH SOME UPTICK FORECAST DUE TO ONSHORE WINDS. ANNAPOLIS IS
FORECAST TO REACH MINOR FLOOD AGAIN TONIGHT DURING HIGH TIDE.
WHILE OTHER LOCATIONS AREN'T CURRENTLY FORECAST TO FLOOD, SOME
COULD COME CLOSE, ESPECIALLY THIS EVENING (I,E HAVRE DE GRACE,
SOLOMONS, AND DAHLGREN). A PASSING COLD FRONT SHOULD REDUCE
WATER LEVELS SLIGHTLY HEADING INTO MONDAY AND TUESDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
MDZ014.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...BRO
NEAR TERM...BRO
SHORT TERM...BRO
LONG TERM...KRR
AVIATION...BRO/KRR
MARINE...BRO/KRR
TIDES/COASTAL FLOODING...LWX
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