176 FXUS63 KIWX 160553 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 153 AM EDT Thu May 16 2024 .KEY MESSAGES... - A period of dry weather this evening into Thursday morning. - More showers with scattered storms at times Thursday through the middle of next week, aside from Sunday. Locally heavy downpours possible. - The strongest storms are most possible on Monday and Tuesday. - Highs in the 70s to low 80s into the middle of next week. && .DISCUSSION... Issued at 243 PM EDT Wed May 15 2024 The broad trough across the eastern half of the CONUS slides east this afternoon and tonight ushering in a drier airmass for tonight. This is expected to scatter out overcast cloudiness, but partly cloudy skies are still possible tonight into Thursday morning. Perhaps a few areas could see BR, fog down to 2 to 4 miles or so, with dew points not dropping too far below 50 degrees and light winds taking over. There's not great confidence on where this occurs, but perhaps east winds and lingering low level moisture can create an environment conducive to it south of US-30. It's a quick reprieve from the rainfall, though, as moisture advects back in as a warm front encroaches on our western flank Thursday morning. It appears the better moisture stays west of I-69 for much of the day allowing the best chance for showers to be there perhaps along any convergent boundary that can come in there. Model confluence on showers in this same area occurs Thursday afternoon as instability between 500 and 1000 J/kg of MUCAPE forms overhead. The NAM appears to bring 30 kts of effective shear into areas south of US-30 so perhaps a strong thunderstorm could be possible, but think they would be isolated. These showers and storms look to spread eastward overnight perhaps along an outflow boundary with the 6 C/km mid level lapse rates and ~200 J/kg of MUCAPE. Continued chances for scattered off an on showers occur on Friday, but despite better chance for seeing 1000 J/kg of MUCAPE, we'll lack in the shear department so severe weather will be harder to come by. Mid level height rises and resultant ridging moves in by Saturday morning restricting the chance for more organized showers and storms, but pop-up showers and storms will be possible with 500 to 1500 J/kg of MUCAPE around. Shear, once again, appears lacking likely restricting overall severity of these storms. The mid level ridging and lack of forcing underneath an area of surface high pressure is expected to keep Sunday the driest of the next few days. Meanwhile, subtropical ridging takes root across the Gulf States next week as a trough digs across the West Coast. This sets up yet another active pattern as areas of vorticity are pushed into the area within a wet and moist environment with 60+F dew points. This allows for chances for showers and thunderstorms as afternoon instability allows for initiating cells. One ingredient for stronger storms makes an attempt to come into the region later Sunday and Monday time frame as 6 to 7 C/km lapse rates edge into the area. Am a little skeptical about how much overturning and mixing can occur within that airmass before it finally gets here, but that could make sustaining larger hail stones possible with some shear around. Between Monday and Tuesday, that does look possible with some shear to work with along with instability. Perhaps more urban areas could see standing water/flooding issues from these repeated rainfall events along with a little lower level of tolerance for increased rainfall in these areas. Highs generally range from the upper 60s to low 80s with the warmest days being Monday and Tuesday. Next Wednesday may provide another brief break as surface high pressure comes into the area. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 151 AM EDT Thu May 16 2024 The main synoptic scale feature to monitor for aviation weather this forecast cycle is a fairly strong upper trough lifting northeast across the Upper Midwest. The southern Great Lakes should receive only a glancing influence from this upper level short wave as brunt of this forcing bypasses northern Indiana to the north. Some better low level moisture transport will lift across the region in advance of this short wave which could set the stage for scattered showers and isolated thunderstorms this afternoon/evening, particularly from northwest Indiana into south central Lower Michigan. Have included a VCSH mention at KSBN this afternoon, and slightly more delayed into this evening at KFWA. While isolated thunderstorms are possible, confidence is still too low for point terminal forecasts to include with the 06Z TAFs. In terms of cigs/vsbys, have maintained low confidence TEMPO MVFR vsby mention at KFWA in the 09Z-12Z period with some patchy fog potential early this morning. Otherwise, VFR conditions are expected to persist through the period with only possible exception being in association with any isolated stronger showers and thunderstorms this afternoon into this evening. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Roller AVIATION...Marsili