314
FXUS61 KCLE 080656
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
256 AM EDT SAT AUG 8 2026
WHAT HAS CHANGED
SHOWERS AND THUNDERSTORMS HAVE TRENDED A LITTLE MORE WIDESPREAD
EARLY THIS MORNING. A SLIGHT RISK FOR EXCESSIVE RAINFALL (LEVEL
2 OF 4) HAS BEEN ADDED FOR MONDAY AND MONDAY NIGHT.
KEY MESSAGES
1) WIDESPREAD SHOWERS AND THUNDERSTORMS WITH HEAVY DOWNPOURS EARLY
THIS MORNING, THEN SCATTERED SHOWERS AND THUNDERSTORMS AHEAD OF A
COLD FRONT LATE THIS AFTERNOON AND EVENING.
2) STRONG TO SEVERE THUNDERSTORMS AND HEAVY RAINFALL ARE POSSIBLE
MONDAY AND MONDAY NIGHT, WITH PERIODS OF HEAVY RAIN POSSIBLY
LINGERING TUESDAY.
3) TURNING GRADUALLY DRIER, COOLER, AND LESS HUMID WEDNESDAY INTO
NEXT WEEKEND.
DISCUSSION
KEY MESSAGE 1...
THE FAMILIAR PATTERN REMAINS THIS MORNING
CHARACTERIZED BY A BROAD MID/UPPER TROUGH OVER SOUTH CENTRAL CANADA
AND THE NORTHERN PLAINS INTO THE GREAT LAKES AND A BROAD MID/UPPER
RIDGE OVER THE DESERT SOUTHWEST AND SOUTHERN PLAINS. THIS IS KEEPING
ACTIVE WNW MID/UPPER FLOW IN PLACE ACROSS THE SOUTHERN GREAT LAKES
AND OHIO VALLEY OVERTOP A QUASI-STATIONARY EAST-WEST FRONT.
THE NEXT IN THE TRAIN OF REINFORCING SHORTWAVES IS MOVING INTO
WESTERN OHIO EARLY THIS MORNING. RAP ANALYSIS HINTS AT A WEAK
SURFACE WAVE TIED TO THIS MID/UPPER SHORTWAVE THAT IS TRAVERSING THE
FRONTAL BOUNDARY, AND THE BOUNDARY IS RETREATING NORTHWARD THIS
MORNING IN RESPONSE. WEAK WARM AIR/THETA E ADVECTION AND 500-1000
JOULES OF MLCAPE IN THE PRESENCE OF A VERY MOIST ENVIRONMENT IS
TRIGGERING A LARGE AREA OF CONVECTION ALONG THE SLOWLY RETREATING
FRONT THIS MORNING. THIS IS BEING AIDED BY UPPER DIFFLUENCE AND MID-
LEVEL PVA, SO EXPECT SHOWERS AND THUNDERSTORMS TO BE WIDESPREAD
AGAIN THIS MORNING AS THEY SLOWLY LIFT EAST AND NORTHEAST. GIVEN
PWATS NEAR 2 INCHES, SKINNY CAPE, AND HIGH FREEZING LEVELS WITH DEEP
WARM CLOUD LAYERS, TORRENTIAL RAINFALL WILL ACCOMPANY THE
CONVECTION, SO WILL NEED TO MONITOR FOR LOCALIZED FLOODING THIS
MORNING, PARTICULARLY IF HEAVY RAIN OCCURS IN SPOTS THAT SAW IT
YESTERDAY. MUCH OF THE LAKESHORE FROM ERIE AND LORAIN COUNTIES
THROUGH CENTRAL AND SOUTHERN CUYAHOGA COUNTY MEASURED 1 TO 3 INCHES
OF RAIN SINCE THURSDAY NIGHT, SO THESE AREAS WILL BE VULNERABLE IF
THE CONVECTION CAN BUILD FARTHER NORTH THIS MORNING.
THIS MORNING ACTIVITY WILL EXIT NW PA BY ABOUT 14Z, AND EXPECT A
LULL WITH QUITE A BIT OF SUNSHINE INTO THIS AFTERNOON ALLOWING
TEMPERATURES TO WARM INTO THE MID/UPPER 80S AHEAD OF THE TRAILING
COLD FRONT. THIS FRONT IS TRENDING A FEW HOURS SLOWER SINCE IT
PARALLELS THE MID/UPPER FLOW BUT SHOULD SINK ACROSS THE REGION THIS
EVENING. POOLING LOW-LEVEL MOISTURE ALONG THE BOUNDARY (DEW POINTS
70-75 F) BENEATH A PLUME OF STEEPER MID-LEVEL LAPSE RATES AROUND 7
C/KM WILL COMBINE WITH THE SURFACE HEATING TO YIELD STRONG
INSTABILITY THIS AFTERNOON AND EVENING. RAP AND NAM FORECAST
SOUNDINGS SUGGEST NEAR 3000 JOULES OF MLCAPE WILL BE POSSIBLE BY MID
TO LATE AFTERNOON, AND WITH JUST ENOUGH DEEP LAYER EFFECTIVE SHEAR
FOR LOOSE CONVECTIVE ORGANIZATION (0-6 KM SHEAR AROUND 25 KNOTS),
COULD SEE A FEW STRONG TO SEVERE STORMS WITH DAMAGING WINDS LATE
THIS AFTERNOON AND EVENING. THE MAIN QUESTION IS CONVECTIVE
COVERAGE. FORECAST SOUNDINGS SHOW QUITE A BIT OF DRY AIR, AND WHILE
THIS COULD AID DOWNBURST POTENTIAL (DCAPE NEAR 1000 JOULES), IT MAY
BE TOO DRY TO GET A LOT OF STORM COVERAGE. THE THINKING IS THAT
THERE WILL BE A BROKEN LINE OF CONVECTION THAT WILL MOVE ESE ACROSS
THE AREA IN THE 21-03Z TIMEFRAME, WITH A FEW WIDELY SCATTERED CELLS
POSSIBLE AHEAD OF THE LINE.
KEY MESSAGE 2...
WEAK SURFACE HIGH PRESSURE WILL BRIEFLY BUILD IN
TONIGHT AND SUNDAY, PUSHING THE FRONT TO NEAR THE OHIO RIVER AND
ALLOWING SOMEWHAT LESS HUMID AIR TO FILTER IN (DEW POINTS IN THE
LOW/MID 60S), HOWEVER, THE FRONT WILL RETREAT BACK NORTH AS A WARM
FRONT SUNDAY NIGHT IN RESPONSE TO A MUCH MORE POTENT MID/UPPER
SHORTWAVE DROPPING INTO THE UPPER MIDWEST. THIS WILL BRING THE RICH
LOW-LEVEL MOISTURE BACK INTO THE REGION FOR SUNDAY NIGHT AND MONDAY
AND POSSIBLY FUEL AN ORGANIZED SEVERE WEATHER AND HEAVY RAINFALL
EVENT.
CONFIDENCE CONTINUES TO BE LOW IN TERMS OF HOW CONVECTION WILL PLAY
OUT SUNDAY NIGHT THROUGH MONDAY NIGHT, SO THIS SET UP HAS A
HIGH CEILING BUT ALSO HIGH BUST POTENTIAL. AS THE POTENT
SHORTWAVE DROPS INTO THE UPPER MIDWEST SUNDAY EVENING, A 30-40
KNOT LOW-LEVEL JET AND NORTHEAST PERIPHERY OF A STOUT EML
SHOULD TRIGGER A SEVERE MCS THAT WILL PROPAGATE ESE INTO
NORTHERN ILLINOIS, NORTHERN INDIANA, AND LOWER MICHIGAN ALONG
THE STRONG INSTABILITY GRADIENT. THIS MCS WILL BE OUTRUNNING THE
BEST INSTABILITY AND UPPER SUPPORT BY THE TIME IT REACHES
NORTHERN OHIO OVERNIGHT SUNDAY NIGHT, BUT INSTABILITY WILL BE
SLOWLY INCREASING AS THE FRONTAL BOUNDARY RETREATS NORTH, SO
EXPECT IT TO AFFECT NORTHERN OHIO IN SOME FASHION SUNDAY NIGHT,
WITH POTENTIAL FOR GUSTY WINDS AND HEAVY DOWNPOURS. BEST CHANCE
FOR THIS WILL BE IN NW OHIO. THE BIGGER IMPACT FROM THIS MCS
WILL BE HOW IT AFFECTS CONVECTIVE REDEVELOPMENT MONDAY. THE
SHORTWAVE IS EXPECTED TO CONTINUE EAST ACROSS THE CENTRAL AND
SOUTHERN GREAT LAKES MONDAY WITH A RESULTANT INCREASE IN MID-
LEVEL FLOW YIELDING 40-50 KNOTS OF DEEP LAYER EFFECTIVE SHEAR.
THIS MID-LEVEL JET WILL ENCOURAGE A LOW-LEVEL JET RESPONSE BY
MONDAY EVENING TO POSSIBLY IGNITE A NEW MCS OVER SOUTHERN LOWER
MICHIGAN, LAKE ERIE, AND NORTHERN OHIO AHEAD OF A COLD FRONT,
BUT THE LOCATION AND STRENGTH OF THIS DEVELOPMENT DEPENDS ON HOW
MUCH CLOUD DEBRIS AND SHOWERS FROM SUNDAY NIGHT LINGER INTO
MONDAY. IF CLOUDS AND LEFTOVER SHOWERS ARE WIDESPREAD INTO
MONDAY AFTERNOON, INSTABILITY WILL BE REDUCED, AND THE NEW
CONVECTION MAY BE LESS ORGANIZED OR DEVELOP OUTSIDE OF OUR AREA.
HOWEVER, IF THE SUNDAY NIGHT ACTIVITY CLEARS OUT QUICKLY MONDAY
MORNING ALLOWING FOR STRONG DESTABILIZATION, THEN A POTENT
SEVERE WEATHER AND HEAVY RAINFALL SET UP COULD MATERIALIZE
MONDAY EVENING INTO MONDAY NIGHT. THE STRONG SHEAR AND
POTENTIALLY STRONG INSTABILITY COULD SUPPORT WIDESPREAD AND
SIGNIFICANT WIND DAMAGE, AS WELL AS EMBEDDED TORNADOES IF THE
HIGHER CEILING CAN BE REACHED, AND A PERSISTENT WESTERLY
NOCTURNAL LOW-LEVEL JET ORIENTED INCREASINGLY PARALLEL TO THE
SAGGING COLD FRONT BY MONDAY NIGHT ALSO SUPPORTS BACKBUILDING
AND TRAINING CONVECTION WITH AN ASSOCIATED FLASH FLOOD RISK. A
WPC SLIGHT RISK FOR EXCESSIVE RAINFALL HAS BEEN INTRODUCED FOR
MOST OF THE AREA MONDAY AND MONDAY NIGHT, AND THE AREA ALSO
REMAINS IN AN SPC SEVERE WEATHER OUTLOOK.
THE FRONT LOOKS TO BE SLOW TO SINK SOUTH TUESDAY AS IT REMAINS
ALIGNED PARALLEL TO THE WNW MID/UPPER FLOW, AND ADDITIONAL SHORTWAVE
ENERGY AND REMNANT OUTFLOW BOUNDARIES INTERACTING WITH IT IN THE
CONTINUED MOIST ENVIRONMENT COULD SUPPORT ADDITIONAL THUNDERSTORMS
AND HEAVY RAINFALL, SO MAINTAINED HIGH POPS THROUGH TUESDAY.
KEY MESSAGE 3...
THE BROAD MID/UPPER TROUGH WILL CONTINUE TO SLOWLY
DEEPEN ACROSS THE GREAT LAKES AND NORTHEAST CONUS WEDNESDAY INTO
NEXT WEEKEND AS A SERIES OF SHORTWAVES GRADUALLY FORCE THE SOUTHERN
CONUS RIDGE INTO THE 4 CORNERS REGION AND HELP THE LONGWAVE TROUGH
TO CARVE OUT AS A CLOSED LOW BECOMES ESTABLISHED NEAR HUDSON BAY.
THIS WILL CONTINUE TO PUSH THE ACTIVE FRONTAL BOUNDARY SLOWLY
SOUTHWARD, SO HAVE GRADUALLY DECREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS MID TO LATE WEEK. THIS WILL ALSO ALLOW PROGRESSIVELY
COOLER AND LESS HUMID CONDITIONS TO FILTER IN, WITH HIGHS IN THE 70S
BY THURSDAY AND FRIDAY AND LOWS DIPPING INTO THE 50S IN SOME AREAS.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
SHOWERS AND THUNDERSTORMS ARE SPREADING ACROSS THE AIRSPACE FROM
SOUTHWEST TO NORTHEAST. STORMS HAVE ALREADY LARGELY CLEARED KFDY
AND WILL MISS KTOL TO THE SOUTHEAST. OTHERWISE, SOME MIX OF TS
AND HEAVIER RAIN SHOULD REACH THE REMAINING TERMINALS THIS
MORNING AND HAVE TIMED IT ACROSS THE AREA. THERE SHOULD BE A
BREAK IN CONVECTIVE ACTIVITY LATER THIS MORNING, WHICH WILL HAVE
A MIX OF LOW VFR AND MVFR CEILINGS ACROSS THE REGION. A SLUGGISH
COLD FRONT WILL ENTER FROM THE NORTHWEST LATER TODAY AND
GENERATE SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY.
COVERAGE WILL BE PROBLEMATIC TO HAVE HIGH CONFIDENCE IN PLACING
AT A TERMINAL AND HAVE TIMED SOME PROB30S ACROSS THE AREA WHEN
THERE COULD BE THE BEST TIMING. THIS TIMING COULD SLOW AS THE
FRONT IS SLOWING DOWN ACROSS THE REGION. BEHIND THE STORMS AND
COLD FRONT, CEILINGS WILL CLEAR AND WINDS WILL SHIFT TO THE
WEST. THERE MAY BE SOME MVFR FOG/MIST CONSIDERATIONS TOWARD THE
END OF THE TAF PERIOD BUT WILL CONSIDER FOR FUTURE TAF
ISSUANCES.
OUTLOOK...NON-VFR BECOMING MORE LIKELY IN SHOWERS AND
THUNDERSTORMS SUNDAY NIGHT THROUGH TUESDAY. SOME STORMS COULD BE
STRONG TO SEVERE DURING THIS TIMEFRAME, ESPECIALLY ON MONDAY.
MARINE
SOUTHWEST FLOW WILL MAINTAIN ACROSS THE LAKE TODAY AHEAD OF A
COLD FRONT. THE COLD FRONT WILL CROSS THE LAKE TONIGHT BRINGING
SOME SCATTERED SHOWER AND STORM ACTIVITY TO THE REGION, FOLLOWED
BY NORTHWEST FLOW ON THE LAKE TONIGHT. A BRIEF RIDGE WILL BUILD
INTO THE REGION AND RETURN SOUTHWEST FLOW TO THE LAKE ON SUNDAY.
A SERIES OF LOW PRESSURE SYSTEMS WITH SHOWER AND THUNDERSTORM
CHANCES WILL MOVE THROUGH THE REGION ON SUNDAY NIGHT THROUGH
TUESDAY. WINDS ON THE LAKE WILL START SOUTHWEST AND BECOME
WESTERLY ON TUESDAY. A WEAK RIDGE WILL REENTER THE REGION ON
WEDNESDAY AND BRING LIGHT BUT VARIABLE FLOW OVER THE LAKE.
OVERALL, ANY MARINE HEADLINES THROUGH THE PERIOD WILL BE TIED TO
SHOWER AND THUNDERSTORM ACTIVITY AND PROBABLY NOT WINDS/WAVES.
CLE WATCHES/WARNINGS/ADVISORIES
OH...NONE.
PA...NONE.
MARINE...NONE.
DISCUSSION...GARUCKAS
AVIATION...SEFCOVIC
MARINE...SEFCOVIC
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