752
FXUS63 KIWX 201007
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
607 AM EDT MON APR 20 2026
KEY MESSAGES
- VERY COLD THIS MORNING BUT TRENDING WARMER STARTING TUESDAY.
- THERE IS A 30% TO 40% CHANCE OF SHOWERS, AND PERHAPS A
THUNDERSTORMS, TUESDAY NIGHT. THEREAFTER, SHOWERS AND
THUNDERSTORMS FRIDAY.
DISCUSSION
ISSUED AT 209 AM EDT MON APR 20 2026
VERY COLD THIS MORNING WITH A FREEZE WARNING IN PLACE. EXPANSIVE
1028MB HIGH PRESSURE SPANS FROM MINNESOTA THROUGH THE NORTHERN
REACHES OF THE OHIO VALLEY. LIGHT WIND TODAY, MOSTLY SUNNY AND HIGH
TEMPERATURES CREEPING TOWARD 50 DEGREES. HIGH PRESSURE CONTINUES ITS
INFLUENCE TONIGHT HAS LOW TEMPERATURES TUMBLE INTO THE 30S ONCE
MORE. HOWEVER, A DEVELOPING SOUTHERLY WIND NEAR 5 TO 10 MPH MAY BE
ENOUGH TO LIMIT FROST FORMATION.
SHARPLY WARMER TUESDAY THROUGH AT LEAST FRIDAY WITH HIGH PRESSURE
AND UPPER-LEVEL TROUGHING TRANSITIONING TO SOMEWHAT ZONAL FLOW
ALOFT. AN ORPHANED FRONTAL ZONE DRAGS THROUGH THE MIDWEST TUESDAY
NIGHT. THIS FRONT ENCOUNTERS WARM, MOIST FLOW FROM THE GULF AMID
CONTINUED SOUTHEAST US HIGH PRESSURE (SIGNIFICANT NEED FOR RAIN IN
THE CAROLINAS) AND SPARKS SCATTERED SHOWERS AND PERHAPS A
THUNDERSTORM FOR THE OVERNIGHT HOURS.
AN UPPER-LEVEL RIDGE IS MAXIMIZED OVERHEAD THURSDAY WHEN
TEMPERATURES NEAR 80 ARE FORECAST, BEFORE A COLD FRONT ARRIVES FROM
WEST TO EAST LATE FRIDAY AFTERNOON. UPPER-LEVEL ENERGY WITH THIS
SYSTEM IS FOCUSED OVER THE UPPER-GREAT LAKES AS THE PARENT LOW
OCCLUDES, BUT A DEVELOPING SECONDARY 500-MB JET MAY PROVIDE ENOUGH
UPPER-LEVEL SUPPORT FOR THUNDERSTORMS. DRIER FOR THE WEEKEND WITH
TEMPERATURES CLOSER TO MORE SEASONABLE LEVELS; 60S/40S HIGH/LOW.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 605 AM EDT MON APR 20 2026
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE TAF PERIOD
BENEATH HIGH PRESSURE. LIGHT AND VARIABLE WIND TO BEGIN THE TAF
BECOMES WESTERLY THIS AFTERNOON, FOLLOWED BY INCREASING
SOUTHERLY FLOW LATE.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FREEZE WARNING UNTIL 11 AM EDT /10 AM CDT/ THIS MORNING FOR
INZ005>009-012>015-017-018-020-022>027-032>034-103-104-
116-203-204-216.
OH...FREEZE WARNING UNTIL 11 AM EDT THIS MORNING FOR OHZ001-002-004-
005-015-016-024-025.
MI...FREEZE WARNING UNTIL 11 AM EDT THIS MORNING FOR MIZ078>081-177-
277.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...BROWN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page