Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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414 FXUS63 KIWX 051025 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 625 AM EDT Wed Jun 5 2024 .KEY MESSAGES... - There is a marginal risk of severe thunderstorms from midday through this evening. -Damaging wind gusts, heavy rain, and hail are the primary hazards. - Warm and humid conditions today give way to cooler than-normal temperatures for much of the next seven days. && .UPDATE... Issued at 623 AM EDT Wed Jun 5 2024 Thunderstorms over central and southwest Illinois will be the ones to watch over the next several hours. These storms are forming ahead of an approaching cold front. Early-morning activity locally has diminished and moved northeast, thus leaving an unimpeded atmosphere for the approaching storms. Surface observations are plenty soupy this hour with temperatures near 70 and some dew points near 70 as well. furthermore, plenty of breaks are noted on satellite as well. Therefore, instability is plentiful this morning and that trend is expected to continue. High resolution guidance is picking up on these trends such that a broken line of storms could get going as far west as the South Bend area, and as early as about 15z (11am EDT). Forecast soundings in this area advertise strong-low level lapse rates, confirming the damaging wind gust threat, while shear continues to be marginal (but acceptable) near 25 to 30 knots. Overall, the severe weather risk remains marginal but the area of concern is shifting westward well outside the I-69 corridor. I`ve passed along this assessment to the SPC for consideration. && .DISCUSSION... Issued at 232 AM EDT Wed Jun 5 2024 A cold front approaching the Mississippi River this morning will bring a marginal risk of severe thunderstorms in the afternoon and evening along and east of I-69 (generally speaking). Damaging wind gusts are the primary concern, followed by heavy rainfall and hail. The timing of these storms remains about 2pm to 8pm EDT. Showers and thunderstorms are ongoing over northwest Indiana early this morning, associated with a MCV lifting in from Illinois, aided further by a strengthening 850-mb jet. Heavy rainfall and perhaps strong wind gusts near 40 mph are possible (as reported over northeast IL). Elsewhere in the forecast area will be untouched by the time the cold front arrives in the afternoon. Temperatures rising in the 80s with dew points near 70 degrees will permit impressive CAPE ahead of the cold front while shear and lapse rates are lacking (25 knots 0-6km and 6C/KM mid-level, respectively). Coverage of storms along the cold front varies among model guidance, likely due to the marginal environment, but guidance favors discrete cells in our area perhaps congealing into a line across central Ohio. Drying out for a time early in the night behind the cold front but a a few showers may arrive later on associated with a screaming, 85- knot jet at 500mb. Moisture transport from the Pacific is somewhat poor, navigating significantly poleward atop a towering ridge over the Four Corners before spilling over the Great Lakes. However, RH remains elevated in the column through Friday, warranting at least slight chance POPs at times as various embedded vorticity maximums rotated around the closed low aloft. Temperature-wise, Friday looks to be the coolest of the next seven with highs right near 70 following two distinct waves of CAA. This upper-level low lingers over the (eastern) Great Lakes into at least the start of next week, if not longer. This complicates the forecast as models do not handle cut-off lows very well. Overall, showers at times are probable paired with cooler-than-normal temperatures for June. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1241 AM EDT Wed Jun 5 2024 Scattered convection, associated with an upper level disturbance, will lift through the KSBN vicinity later tonight with brief vis/cig restrictions possible. A few showers could clip KFWA toward daybreak, though chances remain on the low side. A cold front then swings through KSBN midday, and KFWA this afternoon, with additional rounds of showers/storms anticipated along it. Mainly VFR, though MVFR ceilings may settle in for a time later this morning, mainly at KSBN. VFR/dry otherwise post frontal into Wednesday night. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ UPDATE...Brown DISCUSSION...Brown AVIATION...Steinwedel