Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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820 FXUS63 KIWX 261121 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 721 AM EDT Sun May 26 2024 .KEY MESSAGES... - Showers and thunderstorms expected this afternoon and tonight. Damaging wind, hail and localized flooding will all be possible. There is the possibility of a few tornadoes. - Lingering showers and thunderstorms may impact activities Memorial Day through Wednesday. - Hazardous swimming conditions for Lake Michigan beaches in La Porte County in Indiana and Berrien County in Michigan Memorial Day through Wednesday. && .DISCUSSION... Issued at 349 AM EDT Sun May 26 2024 Warm front boundary associated with a low pressure system over central IA this morning is now pushing into eastern MO and will move east/northeastward this morning. Latest HRRR model has a well defined line of rain/thunderstorms moving into the western parts of the CWA around Noon EDT today, which would be the first batch of strong to severe storms. The line should continue to move east/northeast and get through the rest of the CWA by 6 PM EDT. MU CAPE values around 1000-1200 j/kg late this morning with the warm frontal boundary passage. Bulk shear values of around 25 to 35 knots. Mid level lapse rates of 6.5 to 7.5 deg/km. Downdraft CAPE with boundary passage will sit right around 1000 j/kg. SR Helicity values around 150 m2/s2. So all threats with the first batch will be possible. However, wind threat seems to be the highest threat with hail right behind and one or two qlcs type tornados possible with the line. With PWATS of nearly 200 percent of normal, 1.65 inches, localized flooding will be possible with the first batch of storms but with storm motion perpendicular to the front will limit the widespread flooding issues. With more moist air pumping northward we will see dew points begin to modify higher with mid to upper 60s dew points behind the warm front and ahead of the cold front by early evening. The uncertainty increases with the second batch of storms accompanying the cold front which at this time looks to be more scattered and potentially weaker than the first batch of storms as the airmass was pretty worked over with the convection with the warm front and only a couple hours of recovery will be possible. Even so, there seems to be another increase in CAPE post frontal (500-1000 J/kg) which should be enough instability to allow for convection. Bulk shear will be slightly less with 20 to 30 knots available. These scattered storms look to move through the CWA from about 8 PM EDT until Midnight EDT. There may be a higher threat for localized flooding issues with the second batch of storms as already wet soils will be further saturated with any additional downpours, but PWATS will drop to around 1 inch post warm front storms. Highs today in the high 70s and low 80s. With the cold front through the area by the morning of Memorial Day a cooler airmass will be in place. With troughing sitting over the Great Lakes region several shortwaves will translate through the trough bringing periods of rain showers with even a few embedded thunderstorms each day from Monday through Wednesday. High temperatures will range each of those days from the mid 60s to the low 70s. The coolest day looks to be on Wednesday with most locations struggling to get out of the 60s. By Thursday morning, with the help of clearing skies from the incoming broad ridging pushing into the area late Wednesday, low temperatures on Thursday will drop into the mid 40s. We do start to see a warming trend by the end of the week with the ridge pushing eastward into the area. Thursday highs will be in the 70s for most locations with temps a few degrees cooler near Lake Michigan. Friday and Saturday will see highs in the upper 70s with a few spots seeing the low 80s. Chances of rain showers return on Saturday as a trough pushes through the upper midwest. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 712 AM EDT Sun May 26 2024 VFR conditions will deteriorate to MVFR/IFR this afternoon as a warm front brings chances for showers and thunderstorms through both terminals. Right now have a tempo between 19-21z at both sites for the visibility drops to MVFR/IFR. Ceilings look to stay on the higher side until the second round of showers and storms moves in. Low confidence with respect to this second round, as models are greatly conflicted about how widespread the additional development ahead of cold front rain/storms will be, so maintained a generic VCTS basically 22z-00z-ish, then had the second round of rain and storms impacting the terminal between 00z-4z. Rain and maybe embedded thunder could last through the 6-9z time frame, with visibility and ceilings dropping behind the cold front (moving through overnight). Light ESE flow will strengthen and shift southward through the day, eventually shifting west through Monday morning. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Andersen AVIATION...MCD