


Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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502 FXUS63 KIWX 032354 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 754 PM EDT Thu Apr 3 2025 .KEY MESSAGES... - There is a chance of rain (40-60%) tonight, primarily south of US 24. - Dry to begin Friday followed by an increasing chance of rain from south to north. - A period of heavy rain is expected Friday night through Saturday which will worsen any ongoing flooding. && .DISCUSSION... Issued at 336 PM EDT Thu Apr 3 2025 A broad trough is centered over the Four Corners while a surface low is taking shape over the mid-Mississippi River Valley. Warm air advection is underway and is promoting a slowly blossoming precipitation shield across IL and IN. Cross sections depict a notable dry layer from 925mb to 700mb which will result in virga for the next few hours until saturation can occur, aided in part by improving 500mb jet dynamics. Overall this evening and tonight, a glancing blow of rain to those south of US 24 while the axis of heavy rain is focused toward the central part of Indiana. The western US trough sharpens through Friday and Saturday in response to an upstream ridge moving inland of the West Coast. This results in the heavy rain axis lifting further north into our forecast area. Friday begins dry but rain arrives from south to north through the day. The SPC has a sliver of our far southern counties in a marginal risk for severe weather. The HREF indicates a colocation of sub-500 j/kg MUCAPE and 60 knots of shear. Soundings are otherwise severely capped but could be cold enough to support hail from the strongest cores. Primary window of opportunity would be about 8p to 2am EDT Friday/Saturday. Confidence in severe weather occurring is low. A period of heavy rain is anticipated Friday night through Saturday morning. The placement of the deformation zone is still in question (with the NAM notably north). Such a northern solution could require additional counties to be added to the flood watch. Trends will need to be monitored closely among incoming high resolution guidance. The current forecast calls for about 2 to 3 inches of rain within the watch area, tapering off toward 1 inch in adjacent areas. This will certainly result in additional rises on area waterways. Drying out Sunday morning. Sharply colder by Monday afternoon as a stout and anomalous cold air mass blasts into the Great Lakes. Rain and then ultimately snow showers are expected along and in the wake of this front. Cold temperatures linger through Tuesday, followed by moderation as the trough moves east. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 736 PM EDT Thu Apr 3 2025 VFR conditions and light winds will prevail through this TAF period. However, a narrow trough over the central CONUS will allow disturbances to ride northeastward into central IN overnight. A few light showers may make it into northern IN however dry mid levels will keep most of the precip from making it to the surface. As this trough pivots eastward an influx of moisture will ride northward into the region Friday early evening bringing lower cigs and a chance of showers into the area after 22z Fri. Heavier rainfall amounts will develop after this TAF period on Friday night. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Flood Watch through Sunday morning for INZ009-017-018-020- 022>027-032>034. OH...Flood Watch through Sunday morning for OHZ001-002-004-005-015- 016-024-025. MI...None. MARINE...None. && $$ DISCUSSION...Brown AVIATION...Andersen