Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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719 FXUS63 KIWX 300000 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 800 PM EDT Mon Apr 29 2024 .KEY MESSAGES... - Showers and a rumble of thunder possible this afternoon east of I-69. - Additional chances for showers and thunderstorms expected Friday. - Unseasonably warm through the week with temperatures 70s being attainable. && .DISCUSSION... Issued at 312 PM EDT Mon Apr 29 2024 This afternoon`s pattern is characterized by a strong moisture stream into the area with a connection to the Gulf, which allows 60+F degree dew points to remain across the area into tonight. With the morning showers creating debris clouds, getting 1000 J/kg of MUCAPE and decent low level lapse rates will likely be difficult. Shear appears to be present, but only with pockets of 30 kts of effective shear at best. It`s obvious on the NAM, but the ECWMF shows shades of this as well, that there`s a sort of pre-frontal/ differential heating trough that also helps to limit any thunderstorm production to east of I-69. If we can get some instability to form, perhaps there could be some stronger storms that develop as the NAM and to some extent the HRRR shows mainly east of I-69. The main threat looks to be damaging winds and heavy rain with the moisture loading present. Mid level height rises signal the return of surface high pressure for Tuesday providing a dry day. For Wednesday, a front passes through with forcing dissipating and moisture being a little lower. Perhaps a shower or storm could form, but don`t quite have confidence on where with model disagreement still existing on timing and moisture content. During this midweek period from Tuesday into Thursday, a subtropical southeast CONUS ridge builds and the pattern slows down allowing a trough across the Western CONUS and for showers and storms across the Plains States and Mississippi River Valley. As vorticity from the Western CONUS ejects northeast, it wouldn`t be completely out of the question that a few counties could receive a shower, but think much more of the messaging for this period should be on it being dry. Highs will also be trending warmer with low to mid 70s on Tuesday achieving highs securely into the 80s on Thursday. A resurgence of 60F degree dew points will be possible on Thursday allowing it to feel more humid again, but a better chance of that will be on Friday just out in front of a cold frontal moving in. The ECMWF has 500 to 1000 J/kg, but the shear appears to be lower, which may lessen the severity of it. The front appears to stall out along US-24 or just south of the forecast area, call it in the vicinity if you want, so am not quite ready to remove PoPs in that area quite yet with some lingering instability noted on the ECMWF. Sunday has a better chance to remain dry with mid level height rises taking over and surface high pressure coming in behind the now departing cold front. That departing cold front looks to have stunted the southeast CONUS ridge to some extent even if it still exists for Monday and Tuesday. As such, with a cold front pushing through during this period and 60F degree dew points, we`ll have to watch for another chance for showers and storms as long it times out favorably. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 722 PM EDT Mon Apr 29 2024 Slow moving cold front moving eastward this evening bringing showers and a few embedded thunderstorms across most of the area. KSBN still has a few light showers in the vicinity but should dry out over the next hour or so. KFWA on the other hand will continue to see light to moderate rain for the next several hours as the front eases eastward and then a few lingering light showers/sprinkles through 08z Tue or so. MVFR conditions with lowered cigs and a few short periods during heavier rains expected through 00z Tue for KSBN and through 08z Tue for KFWA. VFR conditions will then return and will see sky cover begin to trend clearer into Tuesday morning/afternoon with mostly light northwest winds, a few gusts Tuesday afternoon may approach 18 knots. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Roller AVIATION...Andersen