Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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805 FXUS63 KIWX 242251 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 651 PM EDT Mon Jun 24 2024 .KEY MESSAGES... - A line of thunderstorms is expected to move through late overnight through early Tuesday morning bringing a chance for locally strong/damaging winds. - Confidence remains low on details regarding Tuesday afternoon/evening showers and thunderstorms. If these develop, large hail, damaging winds, and locally heavy rain will be main threats. - Seasonable temperatures and dry conditions expected Thursday and Friday before additional rain chances return Saturday. && .DISCUSSION... Issued at 250 PM EDT Mon Jun 24 2024 After our extended heat wave last week, we return to a more active, complex weather pattern over the next 24-36 hours. Convection currently in the Dakotas and MN will grow upscale and evolve into a MCS as we head through the evening and overnight hours. Overall agreement is for this complex to maintain intensity through Wisconsin where the greatest instability will reside, along with the stronger shear. A gradual weakening should take place as it works its way southeastward across SE Lake Michigan and Indiana where a rapid dropoff in overnight instability will be located. Nevertheless, mesoscale maintenance of the stronger cells may allow them to produce instances of strong/damaging wind gusts as they push into our forecast area and the updated Day 1 Outlook from SPC now drags a Slight Risk (2 of 5) into North Central Indiana and Southwest Michigan. CAMs have begun to latch onto this better as well, and given the 4mb pressure rises on the HRRR as the MCV moves across the lake, there is some concern for seiche activity along with an increase in wave action and rip current risk leading into Tuesday. Some closer evaluation of this will be needed as we head into the overnight hours... In the wake of the late overnight into early tomorrow morning convective complex, steep low/mid level lapse rates and hot daytime temperatures will contribute to rapid and intense instability across the forecast area. Bulk shear will be limited, ranging from 20-30kt, which will likely prevent a more significant severe episode if anything develops (more below). A corridor of low LCL heights will be favorable for a tornado environment, however, we will need existing surface boundaries to enhance low level helicity as this parameter looks meager. It`s worth noting that confidence in triggers due to the aforementioned earlier convection, and a lack of strong forcing during the day, may keep a lid on afternoon thunderstorms altogether. Therefore, at this time, confidence is very low in Tuesday afternoon/evening severe potential. If anything does develop, the thermodynamic profile will help to create robust updrafts with a hail and damaging wind threat; we`ll just have to see how the AM convection shakes out first. Fortunately, the hottest day of the week will be tomorrow before a frontal passage returns us back into more seasonable temperatures. We will have dry days on Thursday and Friday before another shortwave and surface front brings additional chances for rain and storms. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 651 PM EDT Mon Jun 24 2024 VFR conditions and light winds will persist into the early overnight on the back edge of stable high pressure. Chances for convection (and associated brief vis/cig restrictions and gusty winds) then enter the picture later tonight through early Tuesday afternoon as a MCS likely develops southeast through WI and MI, with a trailing outflow and incoming warm front allowing at least a broken/weakening line of convection to drop south into northern IN, best chances in the 12-16z window. Scattered elevated convection could even develop in advance of the main line in roughly the 9-12z window, though confidence in coverage and timing of convection remains low as activity will outpace better flow and instability. Winds will increase and back more to the west-southwest during the day tomorrow otherwise. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Small Craft Advisory from 2 AM to 2 PM EDT Tuesday for LMZ043- 046. && $$ DISCUSSION...Norman AVIATION...Steinwedel