869
FXUS63 KIWX 181859
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
259 PM EDT SAT APR 18 2026
KEY MESSAGES
- SHOWERS HAVE MOVED EAST OF THE AREA EARLIER TODAY ALLOWING
DRY WEATHER TO PREVAIL.
- UNSEASONABLY COOL WEATHER WILL BRING THE LIKELIHOOD OF FROST
AND FREEZING TEMPERATURES TONIGHT AND SUNDAY NIGHT.
- COOL SUNDAY AND MONDAY, THEN MUCH WARMER TUESDAY THROUGH
FRIDAY WITH HIGHS IN THE 70S AND 80S.
DISCUSSION
ISSUED AT 1201 PM EDT SAT APR 18 2026
STRONG COLD AIR ADVECTION WAS BEHIND A COLD FRONT THAT HAD
MOVED EAST OUT OF NORTHERN INDIANA. UPSTREAM DEW POINTS BEHIND
THE FRONT WERE IN THE LOW TO MID 30S. THIS IS A CLASSIC SET UP
FOR VERY CHILLY EARLY MORNING TEMPERATURES THE NEXT TWO NIGHTS
WITH WINDS BECOMING LIGHT AND WITH THE DRY AND CHILLY ARE OVER
THE FORECAST AREA. IN THIS REGARD, AFTER COLLABORATION WITH
SURROUNDING OFFICES, HAVE ISSUED A FROST ADVISORY AND A FREEZE
WATCH FOR TONIGHT AND TOMORROW NIGHT RESPECTIVELY. LOWS TONIGHT
ARE EXPECTED TO BE BETWEEN 33 AND 35 DEGREES. LOWS SUNDAY NIGHT
WILL RANGE FROM THE MID TO UPPER 20S NEAR THE MICHIGAN BORDER TO
AROUND 30 DEGREES FARTHER SOUTH.
VERY MILD WEATHER IS AHEAD THIS UPCOMING WEEK WITH HIGHS IN THE
70S AND 80S AS UPPER LEVEL RIDGING BUILDS OVER THE EASTERN CONUS
DOWNSTREAM OF AN UPPER LEVEL TROF OVER THE WEST COAST. BOTH THE
ECMWF AND GFS 850 MB TEMPERATURE ANOMALIES ARE VERY IMPRESSIVE
IN THE +8C TO +14C RANGE PER GFS; FULLY SUPPORTIVE OF THESE
WARM TEMPERATURES. PRECIPITABLE WATER VALUES SURGE NORTH LATE
FRIDAY AND SHOULD BE CLOSE TO 1.50" FRIDAY NIGHT. SOME CONCERN
FOR A THUNDERSTORM COMPLEX THAT MAY DEVELOP UPSTREAM AND MOVE
INTO THE WESTERN PART OF THE FORECAST AREA LATE THIS WEEK, BUT
AT THIS TIME UNCERTAINTY IS TOO LOOK TO ATTEMPT TO INCLUDE IN
THE FORECAST AT THIS TIME.
AVIATION /18Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 255 PM EDT SAT APR 18 2026
DRIER AIR WAS SPREADING OVER NORTHERN INDIANA ACCOMPANIED BY STRONG
COLD AIR ADVECTION. THE LATEST VISIBLE SATELLITE SHOWED SKIES WERE
CLEARING OVER NORTHWEST INDIANA. COLD STRATOCU WAS FARTHER NORTH,
BUT THESE CLOUDS ARE NOT EXPECTED TO DEVELOP A CEILING OVER THE
AREA. OVERALL, DRIER AIR WILL ARRIVE AND HELP CLEAR OUT THE MVFR
CLOUDS. AFTER WINDS DECOUPLE TONIGHT, DAYTIME HEATING AND MIXING
WILL OCCUR BY LATE MORNING ALLOWING WIND GUSTS TO TOP 20 KNOTS
AT BOTH TAF SITES.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR LMZ043-046.
DISCUSSION...SKIPPER
AVIATION...SKIPPER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page