424
FXUS63 KIWX 180518
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
118 AM EDT THU JUN 18 2026
KEY MESSAGES
- COOL AND BREEZY TODAY WITH HIGHS AROUND 70 AND GUSTS UP TO 30 MPH.
- LIGHT RAIN IS POSSIBLE TODAY AND SATURDAY. MORE WIDESPREAD
MODERATE RAIN IS EXPECTED ON SUNDAY.
- COOL WEATHER PERSISTS INTO NEXT WEEK WITH PERIODIC LOW
RAINFALL CHANCES.
DISCUSSION
ISSUED AT 118 AM EDT THU JUN 18 2026
990MB SURFACE LOW NOW PULLING INTO THE LOWER GREAT LAKES. TIGHT WNW
GRADIENT IN ITS WAKE WILL YIELD BREEZY CONDITIONS TODAY WITH GUSTS
25-30 MPH THROUGH THE AFTERNOON (HIGHEST NE). LAGGING MIDLEVEL VORT
MAX AND LOW LEVEL CYCLONIC FLOW WILL SUPPORT A FEW SHOWERS THIS
MORNING (AGAIN BEST CHANCES NE HALF) BUT WON'T AMOUNT TO MUCH. COOL
WNW FLOW PERSISTS FOR QUITE A WHILE AND WILL KEEP HIGHS IN THE 70S
MUCH OF THIS PERIOD. ANOTHER WEAK SHORTWAVE PASSES ON SAT WITH A FEW
SHOWERS LIKELY BUT WEAK FORCING AND LIMITED MOISTURE WILL KEEP
COVERAGE LIMITED AND AMOUNTS LIGHT.
A MUCH STRONGER WAVE CROSSES THE REGION ON SUNDAY. GOOD RIGHT
ENTRANCE JET DYNAMICS AND MIDLEVEL CVA WILL SUPPORT A GOOD LOW LEVEL
RESPONSE WITH 40+ KT LLJ, STRONG MOISTURE CONVERGENCE, AND DECENT
CYCLOGENESIS FOR JUNE STANDARDS. A SWATH OF 1-2" OF RAIN IS LIKELY
WITH THIS SYSTEM THOUGH MODELS STILL OSCILLATING IN EXACT TRACK.
WILL HAVE TO KEEP AN EYE ON INSTABILITY VALUES SOUTH OF THE LOW
TRACK GIVEN OBVIOUS HIGH SHEAR BUT FOR NOW PALTRY MIDLEVEL LAPSE
RATES AND OVERALL COOL ENVIRONMENT WITH LOW 60S SURFACE DEWPOINTS
SUGGEST A LIMITED SEVERE RISK. MORE COOL WEATHER THEN CONTINUES INTO
NEXT WEEK WITH A FEW LOW CHANCES FOR LIGHT RAIN DEPENDING ON
SHORTWAVE TRACKS.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 118 AM EDT THU JUN 18 2026
A BRIEF BREAK IN MVFR STRATUS IS EXPECTED THROUGH THE EARLY
MORNING BEFORE CAA FINALLY ARRIVES 12-15Z. THIS CAA WILL SUPPORT
MORE WIDESPREAD MVFR CEILINGS, PARTICULARLY AT KSBN WHERE FUEL-
ALTERNATE IS LIKELY FOR A TIME. CEILINGS SLOWLY LIFT THROUGH
THE AFTERNOON AND RETURN TO VFR BY AROUND 21Z. WNW WINDS GUST UP
TO 25 KTS THROUGH MIDAFTERNOON.
IWX WATCHES/WARNINGS/ADVISORIES
IN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR INZ103.
OH...NONE.
MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ177-277.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...AGD
AVIATION...AGD
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