Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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488 FXUS63 KIWX 290019 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 819 PM EDT Sun Apr 28 2024 .KEY MESSAGES... - Showers and some thunderstorms will be possible this evening into early Monday and again Monday afternoon with gusty winds and heavy rain being the main threats. - Additional chances for showers and thunderstorms expected during mid to late week period next week. - Warm with highs in the 70s through Friday with 80s also possible on Thursday. && .DISCUSSION... Issued at 254 PM EDT Sun Apr 28 2024 The upper low pressure system across the Upper Mississippi Valley moves northeast into Canada this evening through Monday night. During which time, it`ll push its moisture stream into the forecast area tonight. After an afternoon of mostly dry weather, chances for rain are expected to increase west of IN-31 as it moves east. However, the surface convergence breaks down, instability only achieves 500 J/kg of energy, and precipitation amounts in models lower despite continued push of 1 to 1.5 inch PWATs (1 to 3 SDs above normal) along with 30 kts of effective shear into the area. As such, will look to keep likely PoPs at best. Then, as the moisture stream slides east on Monday, the area with the best chance to see any stronger storms appears to be east of IN-15 and perhaps even as far east as east of I-69. The 7 C/km mid level lapse rates depart the area before the afternoon, but there is some maintenance of the 30 kts of effective shear and 500 J/kg MUCAPE so perhaps a damaging wind gust could be had in the moist environment. Shear appears to have some tendency of both boundary-parallel and -perpendicular flow owing to individual cells and perhaps some linear segments as well. With the MBE vectors going into the inner circle perhaps there could be some back building or slow moving cells to allow for a heavy rain allotment with its convective component. Upper divergence appears to return to southeast after 00z Monday night, which could also support the heavy rain component. The moisture stream slides out of the area for Tuesday allowing for a drier day with sunshine to be observed, especially during the afternoon for eastern areas. Highs still reside in the 70s Monday and Tuesday. Tuesday night into Wednesday morning, a deepening progressive, but slightly negatively tilted area of vorticity swings into the Northern Great Lakes, forcing dissipates as precipitation approaches from the west, so will continue with the dry forecast for Wednesday. Additional ridging continues to build in the southeast CONUS Wednesday through Thursday night continuing the dry streak for the area. It won`t be until Friday that we have another chance to see more rain as a cold front comes through. Timing is in question especially as it pertains to if we can receive a convective component. Next weekend looks cooler with highs in the 60s. Saturday leans drier than Sunday, but Sunday`s chance for rain is on the low side as well. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 736 PM EDT Sun Apr 28 2024 Mostly dry conditions will continue at least through 12z Mon however a few light showers ahead of the trough as it continues to shift eastward tonight with another jet streak making its way around the base of the trough. This and the approach of the cold front should allow for an increase in speed convergence and lift which will increase chances of rain showers with even a few embedded storms and will then move eastward through the day on Monday. Currently have rain showers with VCTS for KSBN after 12z with showers after 18z Mon for KFWA. Did mention VCSH for KFWA after 12z Mon. Felt less confident on the exact timing of thunder for KFWA for later in the day so added as PROB30. At this time I have kept VFR conditions through the period, but would not be surprised to have a short period or two with the heavier showers/storms to get a temporary drop in cigs and vsby. Winds will also be gusty at times with gusts around 25-30 knots possible through the period. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Roller AVIATION...Andersen