868
FXUS63 KLOT 220656
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
156 AM CDT WED APR 22 2026
KEY MESSAGES
- ISOLATED TO PERHAPS WIDELY SCATTERED SHOWERS/STORMS THIS
AFTERNOON MAINLY ACROSS PARTS OF NORTHWEST INDIANA.
- NOTABLY COOLER NEAR THE LAKE TODAY, BUT WARMING TO NEAR 80
DEGREES NEARLY AREA-WIDE THURSDAY.
- MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WITH ANOTHER COLD
FRONT VERY LATE THURSDAY NIGHT INTO FRIDAY.
- SEASONABLE AND DRY CONDITIONS OVER THE WEEKEND.
DISCUSSION
ISSUED AT 156 AM CDT WED APR 22 2026
SURFACE OBSERVATIONS, SATELLITE LOOPS, AND RADAR DATA REVEAL A
SOUTHWARD-MOVING COLD FRONT CURRENTLY NEAR MUSKEGON TO
MILWAUKEE, MOVING AT A STEADY CLIP AROUND 25 MPH NEAR THE
LAND/LAKE INTERFACE. THIS BOUNDARY WILL LIKELY CONTINUE TO SURGE
DOWN THE LAKE PRIOR TO DAYBREAK, AND THEN WILL BEING TO OOZE
INLAND. AFTER SUNRISE, INCREASING BOUNDARY LAYER MIXING WILL
SLOW THE FRONT'S SOUTHWESTWARD PROGRESS, INITIALLY LIKELY
GETTING HUNG UP WITHIN THE FIRST 5 MILES OR SO OF THE LAKEFRONT.
THIS BOUNDARY WILL EVENTUALLY GET AN ADDITIONAL PUSH FROM A
DIURNALLY-DEVELOPING LAKE BREEZE AND BEGIN TO MARCH FARTHER
INLAND LATE THIS AFTERNOON AND ESPECIALLY THIS EVENING.
TEMPERATURE TRENDS IN THE VICINITY OF THE LAKE ARE A BIT
UNCERTAIN TODAY GIVEN SOME NOTABLE TIMING DIFFERENCES WITH THE
HANDLING OF THE EVENTUAL SECONDARY LAKE BREEZE PUSH. THAT SAID,
HIGH TEMPERATURES AT THE IMMEDIATE LAKEFRONT WILL LIKELY HOLD IN
THE 50S WHILE AREAS SOUTH OF I-80 APPEAR SET TO RISE WELL INTO
THE 70S AND EVEN LOWER 80S THROUGH THE AFTERNOON.
DEEPER BOUNDARY LAYER MOISTURE WILL RESIDE ACROSS PARTS OF
NORTHWEST INDIANA LATER THIS MORNING AND AFTERNOON. FORECAST
SOUNDINGS LOOK QUITE CAPPED THROUGH THE MORNING, BUT MLCIN IS
EVENTUALLY FORECAST TO ERODE AS TEMPERATURES WARM. WHILE LARGE
SCALE FORCING LOOKS SOMEWHAT WEAK, GENERAL TROUGHING IS FORECAST
TO BE PRESENT ACROSS OUR NORTHWEST INDIANA LOCALES THIS
AFTERNOON AS A MODEST 700 MB SHORTWAVE SCOOTS OUT OF EASTERN
IOWA. THIS, COUPLED WITH INCREASED LOW-LEVEL CONVERGENCE ALONG
THE INLAND-MOVING LAKE BREEZE/FRONT WITHIN A MOIST BOUNDARY
LAYER MAY SUPPORT THE POTENTIAL FOR ISOLATED TO PERHAPS WIDELY
SCATTERED CONVECTION DURING PEAK HEATING. HAVE MAINTAINED SOME
20-30 PERCENT POPS GENERALLY SOUTH OF I-80 AND EAST OF I-57 FOR
THIS. WITH THE DEEPEST BL MOISTURE AND FORCING FORECAST TO
REMAIN JUST EAST OF OUR REGION, EXPECT THE HIGHEST COVERAGE OF
STORMS TO FOCUS ACROSS NORTH CENTRAL AND NORTHEAST INDIANA. IF
MORE ROBUST CONVECTIVE DEVELOPMENT MATERIALIZES, STORM MOTIONS
WOULD LIKELY BE QUITE SLOW, WITH AN ASSOCIATED POTENTIAL FOR
VERY LOCALIZED HEAVY RAINFALL. THIS SIGNAL IS NOT UBIQUITOUS
ACROSS THE HIGH-RES SUITE, BUT AT LEAST A SMATTERING OF
GUIDANCE POINTS TO THIS POTENTIAL FOR AN ANCHORED STORM OF TWO
GETTING CLOSE TO OUR FAR SOUTHEAST LATE IN THE DAY AND EARLY
EVENING. FINALLY, CAN'T RULE OUT THE POTENTIAL FOR A FUNNEL
CLOUD IN THIS ENVIRONMENT, CHARACTERIZED BY STEEPENING 0-1 KM
LAPSE RATES, INCREASING 0-3 KM MLCAPE, FAIRLY LOW DEEP LAYER
SHEAR, AND THE PRESENCE OF ENHANCED VERTICAL VORTICITY NEAR A
SURFACE BOUNDARY.
WHILE SOME ACTIVITY COULD LINGER THROUGH THE EVENING, WE SHOULD
TREND PRECIP-FREE DURING THE OVERNIGHT. SOME GUIDANCE NOW WANTS
TO PUSH SOME LAKE STRATUS/FOG INLAND INTO EARLY THURSDAY
MORNING, BUT WITH THE LOW-LEVEL FLOW TURNING OFFSHORE, HAVE NOT
INCLUDED A FOG MENTION OVER LAND AT THIS POINT, BUT MAY NEED TO
DO SO IN FUTURE UPDATES IF TRENDS CONTINUE. VERY WARM AND BREEZY
CONDITIONS WILL DEVELOP ON THURSDAY AHEAD OF THE NEXT COLD
FRONT. TEMPERATURES APPEAR LIKELY TO PUSH TOWARDS 80 ACROSS A
BROAD SWATH OF THE AREA, AND POTENTIALLY INTO THE MID 80S CLOSER
TO CENTRAL ILLINOIS.
SHOWERS AND THUNDERSTORMS WILL DEVELOP WELL TO OUR WEST THROUGH
THURSDAY AFTERNOON ON A COLD FRONT AND WILL THEN TRACK EASTWARD
INTO OUR AREA EITHER VERY LATE THURSDAY NIGHT OR FRIDAY MORNING.
THE INSTABILITY/SHEAR PARAMETER SPACE REMAINS UNIMPRESSIVE
LOCALLY. THE SEVERE THREAT CONTINUES TO APPEAR LOW IN OUR AREA.
SHOWERS AND SOME STORMS WILL PROBABLY LINGER INTO THE AFTERNOON
BEFORE THE COLD FRONT SWEEPS THROUGH THE AREA. MORE SEASONABLE
CONDITIONS WILL OCCUR OVER THE WEEKEND WITH TEMPERATURES IN THE
60S/LOWER 70S (AND COOLER TEMPERATURES NEAR THE LAKE). ANOTHER
STORM SYSTEM WILL APPROACH THE AREA TOWARDS THE MONDAY-MONDAY
NIGHT TIMEFRAME. LOTS OF VARIABILITY WITH THIS ONE AS THIS WILL
INVOLVE A BROAD TROUGH EJECTION ACROSS THE GREAT BASIN.
DEPENDING ON THE TIMING AND LOCATION OF THE ATTENDANT SURFACE
LOW, THERE COULD BE A STRONG-SEVERE THREAT WITH THIS, BUT MODEL
SPREAD IS TOO HIGH TO HAVE ANY CONFIDENCE IN A PARTICULAR
SOLUTION AT THIS POINT.
CARLAW
AVIATION /06Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 1242 AM CDT WED APR 22 2026
KEY MESSAGES FOR THE 06Z TAF PERIOD:
* POTENTIAL MVFR BR AND/OR STRATUS PREDAWN THROUGH WEDNESDAY
MORNING. LOW CONFIDENCE ON TIMING OF IMPACTS.
* LIKELY MUCH LATER IN TIMING OF W TO NE WIND SHIFT THAN
PREVIOUSLY FORECAST. NOW PROGGED FOR MID-LATE MORNING.
* ANOTHER SIGNAL FOR FOG AND LOW STRATUS WEDNESDAY NIGHT INTO
EARLY THURSDAY. THIS IS ALSO OF LOW CONFIDENCE.
LIGHT WSW'ERLIES WILL PREVAIL INTO WEDNESDAY MORNING. A FRONTAL
BOUNDARY IS PUSHING SOUTH THROUGH SOUTHERN WI TONIGHT, THOUGH
EXPECTED ARRIVAL AT THE TERMINALS AND RESULTANT NE WIND SHIFT
HAS TRENDED LATER IN TIME RECENTLY WITH A SLOWER PROGRESSION OF
THE BOUNDARY ACROSS NORTHERN IL NOW ANTICIPATED. WHILE THERE
REMAINS A SIGNAL FOR EARLIER IN THE MORNING, LATEST MODEL
GUIDANCE FAVORS MID- LATE MORNING, IF NOT EARLY AFTERNOON FOR A
SHIFT TO NE. FORECASTING CLOSER TO MID-MORNING IN THE TAFS, BUT
GOOD CHANCE TIMING WILL NEED TO PUSHED EVEN LATER IN FUTURE
ITERATIONS. LOOKING AT NEAR OR BELOW 10 KT ALL THE WHILE.
THE LATER TIMING OF THE FRONT HAS DRASTICALLY SHIFTED
EXPECTATIONS FOR FOG AND LOW STRATUS IMPACTS TONIGHT INTO EARLY
WEDNESDAY. WITH WINDS NOW EXPECTED TO STAY SW THROUGH THE
OVERNIGHT, FOG SHOULD HAVE A MUCH HARDER TIME BUILDING OVER THE
TERMINALS, ESPECIALLY DENSE FOG. STRONGER SIGNAL EXISTS FOR A
PERIOD OF MVFR CIGS DURING THE EARLIER HALF OF THE MORNING, IF
NOT LINGERING INTO EARLY AFTERNOON. CONFIDENCE IN IMPACTS
THROUGH WEDNESDAY MORNING IS CURRENTLY LOW, BUT NECESSARY AMDS
WILL BE ISSUED TO REFLECT LATEST THINKING.
VFR IS FAVORED WEDNESDAY AFTERNOON INTO EVENING. ANOTHER SIGNAL
EXISTS FOR IMPACTS DUE TO FOG AND LOW STRATUS WEDNESDAY NIGHT
INTO THURSDAY. THIS POTENTIAL IS OF LOW CONFIDENCE, AS WELL.
MAINTAINED VFR IN THE TAF DURING THIS PERIOD FOR NOW, BUT LOOK
FOR LOWER CONDITIONS IN FUTURE FORECASTS AS CONFIDENCE GROWS.
DOOM
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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