647
FXUS63 KIWX 181028
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
628 AM EDT SAT APR 18 2026
KEY MESSAGES
- PERIODS OF RAIN THIS MORNING, BUT THEN NO WIDESPREAD RAIN
CHANCES ARE EXPECTED UNTIL THURSDAY NIGHT INTO FRIDAY.
- MUCH COOLER TEMPERATURES ARRIVE AND PERSIST INTO EARLY NEXT
WEEK WITH CHANCES FOR NEAR OR BELOW FREEZING TEMPS SUNDAY AND
MONDAY MORNING.
DISCUSSION
ISSUED AT 252 AM EDT SAT APR 18 2026
TONIGHT AND SATURDAY:
THE RISK FOR SEVERE WEATHER HAS ENDED FOR TONIGHT. STORMS HAVE
LOST THE INSTABILITY AS EVIDENT BY THE LATEST LIGHTNING TRENDS,
AND ARE NOW REDUCED TO MAINLY RAIN SHOWERS. THESE RAIN SHOWERS
WILL PERSIST OVERNIGHT INTO SATURDAY MORNING AS AN UPPER LEVEL
TROUGH TO THE WEST WILL STILL PROVIDE WIDESPREAD FORCING FOR
ASCENT, BUT PRECIPITATION CHANCES END FROM WEST TO EAST ON
SATURDAY AS COOLER AND DRIER AIR MOVE ACROSS THE REGION IN THE
WAKE OF A COLD FRONT.
ONE CHANGE TO THE FORECAST WAS TO ADD SOME SPRINKLES TO THE
FORECAST FOR AREAS ALONG AND INLAND FROM THE LAKESHORE. FORECAST
SOUNDINGS SHOW STRATUS WITH A NARROW AREA OF INSTABILITY, SO
COULD HAVE SOME OF THE CLOUDS PRODUCE LIGHT PRECIPITATION.
SUNDAY THROUGH FRIDAY:
SEASONABLY COOL TEMPERATURES WILL LAST THROUGH THE WEEKEND, WITH
HIGHS ON SUNDAY STRUGGLING TO REACH 50. A WEAK SHORTWAVE WILL
MOVE ACROSS THE REGION, AND BRING SMALL CHANCES (20 PERCENT) FOR
A FEW RAIN SHOWERS. ON SUNDAY NIGHT HIGH PRESSURE WILL BUILD IN,
LEADING TO CLEAR SKIES AND LIGHT WINDS, WITH OVERNIGHT LOWS
FALLING BELOW FREEZING BY MONDAY MORNING. MONDAYS HIGHS WILL
REBOUND TO NEAR 50S.
LOOKING AHEAD, HIGH PRESSURE WILL MOVE EASTWARD, AND RETURN FLOW
WILL BRING SPRING-LIKE TEMPERATURES BACK ACROSS THE AREA. HIGHS
ON TUESDAY WILL BE IN THE LOW 70S, MID 70S WEDNESDAY, AND NEAR
80 BY THURSDAY.
AS FOR PRECIPITATION CHANCES, THERE IS A SMALL CHANCE (15 TO 20
PERCENT) A BOUNDARY COULD SPARK A FEW SHOWERS AND THUNDERSTORMS
TUESDAY INTO WEDNESDAY. MORE WIDESPREAD RAIN CHANCES (50 TO 60
PERCENT) RETURN LATE THURSDAY INTO FRIDAY AND A LARGER STORM
SYSTEM APPROACHES FROM THE WEST. THE LONG RANGE MACHINE LEARNING
GUIDANCE DOES INDICATE THIS SYSTEM COULD PRODUCE SEVERE WEATHER
ACROSS THE CENTRAL CONUS, BUT THAT IS TOO FAR OUT IN THE FUTURE
TO HAVE MUCH CONFIDENCE IN WHEN OR WHERE.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 619 AM EDT SAT APR 18 2026
EXISTING TAFS WERE ON TRACK OVERALL, REQUIRING ONLY MINOR
ADJUSTMENTS. RAIN AND EMBEDDED THUNDERSTORMS CONTINUE TO
GRADUALLY TRACK EAST AHEAD OF A COLD FRONT, WHICH IS CURRENTLY
EXITING ILLINOIS. WIND BECOMES NORTHWESTERLY BEHIND THIS AND
BREEZY. CANNOT RULE OUT BRIEF PERIOD OF IFR CEILINGS ON EITHER
SIDE OF THIS FRONT, BUT MVFR OR FUEL-ALTERNATE REPRESENTS MOST
OF THE UPSTREAM OBSERVATIONS. LOOK FOR ISOLATED SHOWERS NEAR
KSBN OFF THE LAKE LATE THIS AFTERNOON AS AN UPPER-LEVEL VORT MAX
ROTATES THROUGH. A RETURN TO VFR IS ANTICIPATED AS HIGH
PRESSURE SETTLES IN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR LMZ043-046.
DISCUSSION...NWS
AVIATION...BROWN
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