FXUS63 KIWX 220522 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 122 AM EDT Sun Mar 22 2026 .KEY MESSAGES... - There is a 30-60 percent chance of rain on Sunday with a few thunderstorms possible south of US-24. Severe weather is not expected. - Highs drop into the 40s for Monday but slowly climb back to the 60s by Thursday. - Dry conditions are expected Monday through Wednesday but additional rain is likely on Thursday. && .DISCUSSION... Issued at 145 PM EDT Sat Mar 21 2026 Main forecast concern is thunderstorm potential late tomorrow. A midlevel shortwave is currently entering the northern Great Lakes but becomes increasingly sheared with time as the mid/upper level flow briefly dampens and becomes more zonal late tonight. The most notable aspect of the system at this point is strong low level WAA. Lows tonight likely remain in the 50s given steady southwest wind/WAA. This strong W/SW flow advects modest surface dewpoints (mid/upper 50s) into the area along with a notable EML (midlevel lapse rates over 8 C/km). However, this also results in a strong capping inversion around 750mb for much of the day. The trailing surface cold front that crosses our CWA tomorrow arrives very early, reaching the US-24 corridor by 15-16Z. This significantly limits the potential for surface-based diurnal destabilization and, outside some broad low level convergence, this front doesn't have much available forcing for ascent (certainly not enough to overcome a strong cap, at least until a secondary shortwave arrives later tomorrow evening). In fact, forecast soundings show virtually no opportunity for surface-based convection with a strong cap ahead of the front and significant 1000-850mb CAA behind the front. There is still some postfrontal MUCAPE available as midlevel lapse rates remain on the high side but depth and strength of low level stable layer suggests small hail as the only potential threat. By the time the secondary shortwave arrives and diurnal destabilization is maximized (21-03Z), the surface front is already well SE of our area. Will maintain a thunderstorm mention and won't rule out some small hail south of US-24 but overall the severe risk appears very low. Rest of the forecast is relatively quiet as Canadian high pressure settles into the region for the Mon-Wed period. Highs Monday drop into the 40s with 850mb temps near -5C. Slow but steady moderation expected on Tue with WAA really ramping up late Wed. This will be our next chance of precip, particularly into Thu as another modest wave crosses the northern Great Lakes and sends a sharp cold front through our area. This system looks very similar to Sunday with decent theta-e advection ahead of the front but lackluster mid/upper level support for ascent in our area. Still plenty of time for adjustments here though. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 120 AM EDT Sun Mar 22 2026 A low pressure system moves through the Central Great Lakes this morning pushing a cold front southeastward through the area. With the arrival of a line of 700 mb vorticity, pushing into the area around 15z, models are already initiating showers and maybe a thunderstorm or two that could produce some hail. This quickly congeals into a line and shifts southward slowly, reaching FWA around 00z. It would appear that that's just showers moving through though and that the better chance for strong to severe storms resides south of even FWA for Sunday. With the passage of the cold front, we'll also have to watch for the formation of MVFR stratus as well as gusty winds up to around 25 kts around the evening time frame. It appears there's some uncertainty with the starting point of MVFR CIGs at SBN so will go with a tempo group until greater confidence can be realized. LLWS will also be possible at the start of the taf into this morning. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Small Craft Advisory from noon today to 3 PM EDT Monday for LMZ043-046. && $$ DISCUSSION...AGD AVIATION...Roller