Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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633 FXUS63 KIWX 271731 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 131 PM EDT Thu Jun 27 2024 .KEY MESSAGES... - Hazardous swimming conditions are expected on Lake Michigan today. Dangerous currents are likely, in addition to waves of 3 to 5 feet. - Friday we`ll see increasing clouds from west to east through the day, with highs in the upper 70s and low to mid 80s. Chances for showers and thunderstorms begin Friday evening and persist through Saturday night. && .DISCUSSION... Issued at 422 AM EDT Thu Jun 27 2024 Patchy fog developed this morning along US 30 and southward, with a couple locations in Cass and White Counties in IN dropping to about 1/4 to 3/4 of a mile for a couple hours. Was considering an SPS, however in the last hour there was rapid improvement, likely due to a very slight increase in wind speed and drop in humidity behind a weak surface trough. Winds are expected to continue to stay up around 5 mph or greater through morning hours in the north and west, with the far southern CWA near Grant/Blackford/Portland, IN Counties still showing calm winds with visibility between 1SM or less on the observations. It is possible some fog re-develops, or becomes more widespread in the area, especially where winds stay on the calm side further south for longer. I will hold off on any SPS until I see more consistent observations of 1 mile or less. Otherwise, I think most places will linger between 2-5SM until sunrise at worst, then improve. Quiet weather conditions today and during the day on Friday thanks to the upper level ridge and surface high building over the Great Lakes. Highs will be in the 70s today, then rise into the upper 70s and low to mid 80s Friday. Lows will be around 60 degrees. Otherwise, northerly winds behind the trough that is moving through right now have picked up on Lake Michigan to around 10 to 20 mph with gusts up to around 25 mph. Surface high pressure builds in rapidly behind the trough through the day, and is will be favorably positioned to allow for slightly gustier N-NE flow and longer fetch on Lake Michigan. Waves quickly came up to around 4-5 feet per the latest observations at Michigan City, IN Buoy and Bridgman, MI-with wave periods around 4-5 seconds. Wave direction will be more shore- parallel further north and become more oblique in La Porte county, IN. This will generate a strong southward flowing longshore current, which will re-direct offshore as a structural current on the north side of any piers or breakwalls. Rip currents are possible, but more likely further south in LaPorte where the wave angles of approach relative to shore fall more into the 30-59 degree range. Furthermore, if winds shift more N-NW this afternoon with the lake breeze, the more direct wave angle of approach, in combination with wave heights of 2 to 5 feet (lesser this afternoon), will make rip currents more likely within the sandbars. Maintained the going high swim risk and left the beach hazards statement as is (ending at 21z today). It`s possible if winds stay stronger than forecast and have a more NW-component to the wind/wave direction (vs N-NE) we may need to extend the beach hazards statement through this evening, particularly at La Porte where the conditions are most favorable longer into the day. Stay dry when waves are high, and steer clear of the piers! Waves could wash you off the pier and into the water, where you will most certainly be met with a staunch structural current that pulls you to deeper water. Those visiting the beaches should plan to stay out of the water. Last but not least SPC has added our entire CWA to a Marginal Risk for strong to severe storms on Saturday, which is reasonable given the forecasted synoptic pattern. It`s somewhat convoluted this far out, however it appears there are two potential rounds of storms, the first with the surface warm front lifting northward Friday night into Saturday morning (with a weak shortwave rippling through the upper level flow). The second round would be from around 15z -21z Saturday when a cold front moves west to east across our CWA. In terms of severe weather, the best potential will be with the cold front in the afternoon hours. The first round may not even develop over our area (some of the guidance pops it just east of us, some have little to no precipitation with it. Strong moisture transport will be ongoing from the gulf thanks to return flow over our exiting high pressure system (Sitting over the Atlantic by 6z Sat), with pwats reaching 150 to 200 percent of normal! Second, we have decent synoptic forcing with the cold front, 0-6 km bulk shear of 35 to 45 knots, and lastly-we will likely have some instability (models have between 400-1200 J/kg. This is of course conditional upon the first round-if it develops, how much convective debris is leftover, and how quick we can recover. It will also depend on timing, some of the models suggest the cold front coming through in the 12-15z time frame, which could limit the intensity of the storms (versus when instability is maximized further east as they have the best chance to recover from morning convection). Mid level lapse rates aren`t that great-around 5-6C/km, which could limit intensity as well, but it`s definitely worth watching. Sunday into Monday will be cooler and dry with highs in the 70s and low 80s. Additional rain and storm chances approach for the middle of next week. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 125 PM EDT Thu Jun 27 2024 VFR conditions expected through this TAF period with synoptic ridging in place. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement until 4 PM CDT this afternoon for INZ103. OH...None. MI...Beach Hazards Statement until 5 PM EDT this afternoon for MIZ177-277. MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LMZ043- 046. && $$ DISCUSSION...MCD AVIATION...Andersen