905
FXUS63 KIWX 081803
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
203 PM EDT SAT AUG 8 2026
KEY MESSAGES
- THERE IS A SLIGHT CHANCE (20%) FOR A BRIEF SHOWER OR STORM THIS
AFTERNOON ALONG AND SOUTH OF THE US 24 CORRIDOR.
- AN ACTIVE PATTERN BRINGS PERIODIC CHANCES FOR THUNDERSTORMS
SUNDAY AFTERNOON THROUGH THE MIDDLE OF THE UPCOMING WEEK.
SOME STORMS COULD BE SEVERE AND MAY ALSO RESULT IN FLASH
FLOODING, ESPECIALLY SUNDAY NIGHT THROUGH MONDAY NIGHT.
- SEASONABLE TEMPERATURES ARE EXPECTED TO PERSIST.
DISCUSSION
ISSUED AT 203 PM EDT SAT AUG 8 2026
A COLD FRONT WILL SAG SOUTHEAST THROUGH NORTHEAST IN AND NORTHWEST
OH THIS AFTERNOON. THIS FRONT WILL HAVE UP TO NEAR 2000 J/KG OF
MLCAPE TO WORK WITH. HOWEVER, LACKING DEEP FORCING/MOISTURE, AND
ONLY 15-20 KTS OF EFFECTIVE SHEAR, SHOULD KEEP ANY CONVECTION SUB-
SEVERE AND ISOLATED (10-30%) ALONG THE FRONT. DRIER AIR THEN BRIEFLY
SETTLES IN POST-FRONTAL TONIGHT AND SUNDAY MORNING, WITH THE
POTENTIAL FOR PATCHY FOG EARLY SUNDAY AS WINDS GO LIGHT/CALM UNDER A
MAINLY CLEAR SKY.
THE AFOREMENTIONED FRONTAL BOUNDARY WILL LIFT BACK NORTHEAST TOWARD
THE MI STATE LINE SUNDAY AFTERNOON INTO SUNDAY NIGHT ON THE NOSE OF
INCREASING LOW LEVEL WEST-SOUTHWEST FLOW. THIS WILL ALLOW VERY
MUGGY/UNSTABLE AIR TO ADVECT BACK INTO THE LOWER GREAT LAKES. THIS
WILL SET THE STAGE FOR A PROLONGED, CONVECTIVELY ACTIVE PERIOD
ACROSS THE REGION THROUGH MIDWEEK AS SEVERAL LOW AMPLITUDE
SHORTWAVES SEND CONVECTIVE COMPLEXES THROUGH ON THE SOUTHERN FRINGES
OF DEVELOPING WEST-NORTHWEST FLOW ALOFT.
CHANCES FOR CONVECTION WILL ENTER THE PICTURE SUNDAY AFTERNOON INTO
EARLY SUNDAY EVENING WITH THE INITIAL THETA-E SURGE AND SOME
SEMBLANCE OF AN INCOMING MCS FROM THE WEST. THE BULK OF THE AREA MAY
SEE THIS FEATURE IN A WEAKENING, MORE ELEVATED STATE, THOUGH
COULD SEE A FEW CELLS ROOTED IN THE SURFACE (POTENTIALLY SEVERE)
INTO NORTHWEST IN, DEPENDING ON THE TIMING/INTENSITY OF
CONVECTION, AND THE POSITIONING OF THE SFC WARM FRONT. 12Z CAMS
DID COME INTO BETTER AGREEMENT ON ANOTHER SUBTLE IMPULSE
INVIGORATING A CLUSTER OF CONVECTION ALONG THE FRONTAL SLOPE
LATER SUNDAY NIGHT OVER MAINLY NORTHERN ZONES, POSSIBLY SINKING
SOUTH OVER THE AREA THROUGH MID MORNING MONDAY. FLOODING APPEARS
TO BE THE PRIMARY RISK, THOUGH A LOW END WIND THREAT COULD
EMERGE IF A DECENT COLD POOL BECOMES ESTABLISHED.
FORECAST SPECIFICS BECOME INCREASINGLY UNCERTAIN WITH TIME MONDAY
THROUGH WEDNESDAY AS WHERE THE NEXT SEVERAL CONVECTIVE CLUSTERS
TRACK WILL DEPEND ON HOW THE PREVIOUS CONVECTIVE CYCLE PLAYED OUT,
AND HOW ANY COLD POOLS MODULATE WHERE MESOSCALE COMPOSITE OUTFLOW
BOUNDARIES SET UP FOR RENEWED DIURNALLY DRIVEN THUNDERSTORM
ACTIVITY. IT IS WORTH NOTING THAT SHEAR/INSTABILITY/MOISTURE
PROFILES WILL SUPPORT THE POTENTIAL FOR SEVERE THUNDERSTORMS AND
FLOODING, PARTICULARLY LATE MONDAY AFTERNOON INTO MONDAY NIGHT.
OTHERWISE, GIVEN THE LOW CONFIDENCE, HELD CLOSE TO NBM GUIDANCE FOR
POPS AND TEMPS IN WHAT COULD BE A FAIRLY ACTIVE PERIOD.
MODELS OVERALL CONTINUE TO SUPPORT SOME SUPPRESSION BY THURSDAY AND
FRIDAY AS TROUGHING INTO THE NORTHEAST US LIKELY FORCES THE
BOUNDARY AND ASSOCIATED HUMIDITY/MOISTURE OFF TO THE SOUTH.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 144 PM EDT SAT AUG 8 2026
A WEAK COOL FRONT WILL CONTINUE TO TRACK EAST ACROSS NORTHEAST
INDIANA THROUGH THE REMAINDER OF THE AFTERNOON. RADAR IMAGERY
OVER PAST HOUR OR TWO HAS EXHIBITED SOME SIGNS OF A FEW CELLS
TRYING TO DEVELOP IMMEDIATELY AHEAD OF THE FRONT, BUT THE
TEMPORAL WINDOW OF THIS DEVELOPMENT APPEARS QUITE NARROW AT
KFWA, AND CONFIDENCE TO INCLUDE REMAINS TOO LOW AT THIS TIME. A
LOW LEVEL ANTICYCLONE WILL BUILD INTO THE AREA TONIGHT BEHIND
THIS FRONT WHICH SHOULD BE CONDUCIVE FOR GOOD RADIATIONAL
COOLING. RELATIVELY HIGH CROSSOVER TEMPS SHOULD SUPPORT SOME
MORE FOG FORMATION EARLY SUNDAY MORNING WITH GREATEST CONFIDENCE
OF IFR OR SUB IFR CONDITIONS AT KFWA. PERTURBED NORTHWEST FLOW
AND RETURN WARM/MOIST ADVECTION ON SUNDAY WILL INTRODUCE A
GREATER RISK OF SHOWERS AND THUNDERSTORMS, BUT NOT LIKELY UNTIL
LATER IN THE AFTERNOON OR SUNDAY NIGHT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...STEINWEDEL
AVIATION...MARSILI
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page