505
FXUS61 KLWX 262340
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
740 PM EDT WED AUG 26 2026
WHAT HAS CHANGED
NO CHANGES HAVE BEEN MADE TO THE FORECAST. LATEST MODEL GUIDANCE
HAS YET TO BOLSTER CONFIDENCE IN DETAILS OF STORMS THURSDAY.
KEY MESSAGES
- 1) SEVERE THUNDERSTORMS ARE POSSIBLE THURSDAY AMIDST
INCREASINGLY WARM AND HUMID CONDITIONS.
- 2) DRIER CONDITIONS HEADING INTO THE WEEKEND, WITH INCREASINGLY
HOT & HUMID CONDITIONS AT THE START OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...SEVERE THUNDERSTORMS ARE POSSIBLE THURSDAY AMIDST
INCREASINGLY WARM AND HUMID CONDITIONS.
MOISTURE RETURN INCREASES OVERNIGHT ALONG A NORTHWARD-LIFTING
WARM FRONT, WHICH COULD RESULT IN SOME ISOLATED TO SCATTERED
SHOWERS AND STORMS. THERE'S NOT A LOT OF MODEL AGREEMENT ON
WHERE OR WHEN (OR EVEN IF) THIS CONVECTION DEVELOPS, ALTHOUGH
ELEVATED INSTABILITY DOES GRADUALLY ADVECT NORTHWARD. THERE IS
SLIGHTLY MORE CONSENSUS CLOSER TO THE CHESAPEAKE BAY ON EITHER
SIDE OF SUNRISE, SO THAT IS WHERE THE MENTIONABLE CHANCES RESIDE
FOR NOW.
MORE NOTABLE FORCING ARRIVES THURSDAY AS AN UPPER LEVEL TROUGH
AND SURFACE COLD FRONT APPROACH FROM THE NORTHWEST. HOWEVER,
THESE FORCING FEATURES MAY BE SOMEWHAT DISPLACED FROM THE LOCAL
AREA DURING PEAK DIURNAL HEATING. THE FRONT WILL LAG TO OUR
NORTHWEST, WHILE THE STRONGEST FORCING WITH THE TROUGH PASSES
TO THE NORTH. A SECONDARY SHORTWAVE MAY APPROACH BUT NOT UNTIL
THE EVENING. THUS THERE REMAINS SOME UNCERTAINTY IN THE COVERAGE
AND TIMING OF ANY SHOWERS AND THUNDERSTORMS, ALTHOUGH THERE IS
SOME MODEL CONSENSUS ON DEVELOPMENT ALONG A SURFACE TROUGH
BETWEEN THE I-95 AND I-81 CORRIDORS BY MID AFTERNOON. RESIDUAL
CLOUD COVER AND ANY LEFTOVER MORNING SHOWERS COULD PUT A DAMPER
ON INSTABILITY. THEN, ESPECIALLY FOR AREAS NEAR AND EAST OF
I-95, CONVECTION MAY NOT ARRIVE UNTIL AFTER SUNSET, WHEN IT
COULD BE WEAKENING. HOWEVER, IF EVERYTHING DOES COME TOGETHER,
MODERATE INSTABILITY COMBINED WITH DEEP-LAYER SHEAR OF AROUND
25-35 KT COULD RESULT IN SOME SEVERE THUNDERSTORMS. DAMAGING
WINDS ARE THE PRIMARY THREAT. MODERATE MID LEVEL LAPSE RATES,
STRONG WINDS IN THE UPPER ATMOSPHERE, AND RELATIVELY LIGHT LOW
LEVEL WINDS COULD ALSO RESULT IN SOME SEVERE LEVEL HAIL.
WHILE THERE IS SOME LOW LEVEL CURVATURE TO HODOGRAPHS, IT'S
UNCLEAR IF THERE WILL BE SUFFICIENT SHEAR FOR A TORNADO THREAT.
WE WILL HAVE TO MONITOR HEAVY RAIN POTENTIAL AS WELL, SINCE
RELATIVELY UNIDIRECTIONAL FLOW RELATIVE TO THE SURFACE TROUGH
COULD RESULT IN SOME TRAINING (HINTED AT BY SPLOTCHES OF HIGHER
QPF IN SOME CAMS). AT THE MOMENT, THIS THREAT APPEARS HIGHER TO
OUR NORTH, AND PRECIPITABLE WATER VALUES AND WARM CLOUD DEPTHS
ARE RELATIVELY MODEST. THUS NO FLOOD WATCHES ARE PLANNED AT THIS
TIME. WHILE SOME SHOWERS AND STORMS MAY LINGER INTO THE NIGHT,
THE SEVERE WEATHER THREAT SHOULD BE WINDING DOWN BY MID TO LATE
EVENING.
THE COLD FRONT MAY BISECT THE AREA BY FRIDAY MORNING WHILE THE
MID/UPPER LEVEL TROUGH AXIS REMAINS TO THE WEST. SOME SHOWERS
AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE NEAR AND SOUTH OF
THE FRONT, ALTHOUGH THE RISK FOR STRONG THUNDERSTORMS IS LOWER.
KEY MESSAGE 2...DRIER CONDITIONS HEADING INTO THE WEEKEND, WITH
INCREASINGLY HOT & HUMID CONDITIONS AT THE START OF NEXT WEEK.
HEIGHTS BEGIN TO RISE SATURDAY AS AN UPPER LEVEL LOW DRIFTS
EASTWARD INTO NORTHERN QUEBEC. SURFACE HIGH PRESSURE WILL BUILD
FROM THE GREAT LAKES TOWARD THE NORTHERN MID ATLANTIC, WHICH
SHOULD PUSH THE COLD FRONT SOUTH ENOUGH TO KEEP MOST AREAS DRY.
HOWEVER, SOME CONVERGENCE ALONG THE APPALACHIANS COULD RESULT IN
AN ISOLATED AFTERNOON SHOWER. TEMPERATURES REMAIN SEASONABLE
DURING THIS PERIOD, WITH DAILY HIGHS RANGING IN THE MID-TO-
UPPER 80S DURING THE DAY.
TOWARDS THE START OF NEXT WEEK, BROAD UPPER-LEVEL RIDGING STARTS TO
BUILD OVER THE SOUTHEAST. COMBINED WITH RELATIVELY MOIST AIR ALOFT,
HEAT & HUMIDITY HERE WILL START TO FEEL LIKE PEAK SUMMERTIME
CONDITIONS ONCE AGAIN. TEMPERATURES RISING TO THE LOWER TO MID
90S COMBINED WITH INCREASING DEW POINTS MAY RESULT IN HEAT INDEX
VALUES IN THE UPPER 90S TO JUST ABOVE 100. 850 MB TEMP
ANOMALIES SHOW THIS PATTERN ONLY CONTINUING TO BUILD IN THE
LONG- TERM, WHICH MAY LEAD TO A WARMER-THAN- AVERAGE START TO
SEPTEMBER SHOULD THIS PATTERN PERSIST. THUNDERSTORM CHANCES
COULD GRADUALLY INCREASE DURING THIS PERIOD AS RIDGING
TRANSITIONS OFFSHORE, ALTHOUGH FORCING APPEARS MINIMAL THROUGH
AT LEAST TUESDAY. REGARDLESS, ANTICIPATE A RETURN TO SUMMERTIME
HEAT & HUMIDITY HERE IN THE MID- ATLANTIC.
AVIATION /00Z THURSDAY THROUGH MONDAY/
A WARM FRONT LIFTING NORTH TONIGHT MAY BRING SOME ISOLATED TO
SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM. THE GREATEST MODEL
CONSENSUS IN CLOSER TO THE CHESAPEAKE BAY A FEW HOURS EITHER
SIDE OF SUNRISE. THUS INCLUDED PROB30 GROUPS FOR BWI AND MTN.
A COLD FRONT WILL APPROACH THE REGION ON THURSDAY. A FEW STRONG
TO SEVERE STORMS ARE POSSIBLE DURING THE AFTERNOON/EVENING,
WITH GUSTY WINDS BEING THE PRIMARY THREAT. TIMING AND COVERAGE
ARE STILL A BIT UNCERTAIN, SO ONLY HAVE PROB30 MENTIONED IN THE
TAFS FOR NOW.
AS THE FRONT STALLS NEARBY THURSDAY NIGHT, SOME MVFR TO IFR
CEILINGS OR VISIBILITIES MAY DEVELOP. CURRENT MODELS SEEM TO BE
FAVORING FOG, ESPECIALLY WEST OF THE METRO AREAS. SHOWERS AND
STORMS COULD EVEN REDEVELOP FRIDAY, BUT UNSURE IF THIS WOULD
IMPACT ANY OF THE TERMINALS (CHO WOULD HAVE THE HIGHEST CHANCE).
PREVAILING VFR CONDITIONS ARE EXPECTED SATURDAY THROUGH MONDAY
AS HIGH PRESSURE BUILDS ACROSS THE AREA.
MARINE
A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH 6 AM FOR MANY
LOCATIONS ALONG THE CHESAPEAKE BAY DUE TO SOUTHERLY CHANNELING.
WITH THE NEXT COLD FRONT NOT ARRIVING UNTIL LATE THURSDAY,
THERE ARE SOME HINTS OF SOME 15 TO 20 KNOT SOUTHERLY GUSTS
CONTINUING OR RENEWING THURSDAY, ESPECIALLY BY AFTERNOON.
ANOTHER SCA MAY BE NEEDED. THE FRONT WILL ALSO BRING THE RISK
OF STRONG, GUSTY THUNDERSTORMS, WHICH WOULD LIKELY NECESSITATE
SMWS. SOME THUNDERSTORMS ARE EVEN POSSIBLE AROUND SUNRISE, BUT
THE GREATEST RISK FOR SEVERE THUNDERSTORMS WILL BE DURING THE
LATE AFTERNOON AND EVENING.
SUB-SMALL CRAFT ADVISORY LEVEL WINDS ARE EXPECTED ON FRIDAY AS A
COLD FRONT MOVES IN FROM THE NORTHWEST. WHILE SOME ADDITIONAL
THUNDERSTORMS ARE POSSIBLE, THE GREATER RISK MAY BE SOUTH OF
MARYLAND. SUB-SCA LEVEL NORTH TO NORTHEASTERLY WINDS ARE
FORECAST FOR SATURDAY, BECOMING SOUTHERLY SUNDAY AS HIGH
PRESSURE PUSHES TO THE EAST.
TIDES/COASTAL FLOODING
INCREASING SOUTHERLY FLOW CONTINUES THROUGH TONIGHT, LEADING TO
RISING WATER LEVELS. MOST LOCATIONS WILL ONLY SEE ACTION
STAGES, BUT ANNAPOLIS COULD APPROACH MINOR FLOOD STAGE EARLY
THURSDAY MORNING. WITH THE LATEST FORECAST ONLY BARELY REACHING
FLOOD STAGE, WILL HOLD OFF ON AN ADVISORY UNTIL CONFIDENCE IN
THE WATER LEVEL TRENDS INCREASES.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ531>534-
537-539>541-543.
DISCUSSION...ADS/DHOF/CJL/SRT
AVIATION...ADS/DHOF/CJL/SRT
MARINE...ADS/DHOF/CJL/SRT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page