Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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265 FXUS63 KIWX 231715 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 115 PM EDT Mon Sep 23 2024 .KEY MESSAGES... - Dry today and not as warm with highs in the 70s. - Scattered showers and thunderstorms arrive Tuesday and linger through much of the day. - Dry midweek before a low chance (20-30%) of showers late this week into the weekend. && .DISCUSSION... Issued at 250 AM EDT Mon Sep 23 2024 The surface low that brought welcome rain to the area is now over the eastern Great Lakes. Plenty of clouds upstream, however, associated with a Pacific moisture plume arriving atop a Southeast US Ridge. While dry weather is anticipated today, a surface low lifts in from the southern Mississippi River Valley tonight. This brings showers and thunderstorms by daybreak Tuesday that lingers most of the day. I fear there is some bust potential with how widespread this rainfall is. Guidance varies notably with where the axis of heavy rainfall occurs. This primarily hinges on how quickly showers and thunderstorms develop in the vicinity of a strengthening 500-mb jet, improving moisture transport, and potential deepening of the surface low. Generally speaking, rain totals will be notably less Lakeside, while those in northeast Indiana northwest Ohio could be in line for 0.75"-1" especially if thunderstorms develop in the afternoon. Some CAMs indicate a high likelihood of thunderstorms Tuesday afternoon in the vicinity of the low`s triple point and baroclinic zone aloft. Forecast soundings are characterized by tall, skinny CAPE profiles and increasing shear (30 knots 0-6km). Low- level lapse rates pale in comparison to Friday when two microbursts occurred. Nonetheless, 7 C/km represents an adequate value for an isolated damaging wind threat. Hodographs present some concern for rotating mesocyclones as well. This all will be worth monitoring over the next 24 hours and will hinge on how well we can destabilize Tuesday afternoon. Drying out Wednesday with highs in the low-to-mid 70s. A subtle warming trend follows as heights rise aloft in response to a ridge just east of the Four Corners. Trouble is brewing in the Gulf of Mexico and the tropical system that follows could bring rain to at least a portion of our area over the weekend. First, said moisture would need to overcome a Great Lakes ridge (sound familiar?). At this distance, hard to deviate much from the in- house blend which calls for 20-30% chance of showers late this week and into the weekend. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 114 PM EDT Mon Sep 23 2024 Shortwave trough and attendant sfc wave over MO will lift out across the terminals Tue. Post frontal stratus holding firm so far through this morning yet should mix a bit higher through this afternoon. However increasing moisture flux late tonight and overspread of large, incoming rain shield out of srn/cntrl IL will bring about widespread IFR conditions by daybreak and continue through much of Tue. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement until 4 PM CDT this afternoon for INZ103. OH...None. MI...Beach Hazards Statement until 5 PM EDT this afternoon for MIZ177-277. MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LMZ043- 046. && $$ DISCUSSION...Brown AVIATION...T