textproduct: Gaylord

KEY MESSAGES

- Heat and humidity continues through the end of the week.

- Remaining active today through Friday with multiple rounds of thunderstorms. Large hail, damaging winds, and heavy rainfall possible.

- Still warm, but not nearly as humid this weekend into next week.

DISCUSSION

Issued at 200 AM EDT Wed Jul 1 2026

Pattern Synopsis and Forecast:

Long story short, heat and humidity continues through the end of the week with low predictability in thunderstorm chances.

Hot and humid conditions persist today through the end of the week, peaking today through Thursday. Temperatures rise into the upper 80s to mid 90s with dewpoints in the low to mid 70s, fostering heat indices in the mid 90s to low 100s at least, locally higher. As such, heat advisory will stay put. If we remain clear, high temperatures may eclipse yesterday and heat indices will likely be well above 100F, dangerous for those without adequate heating and vulnerable populations/pets. Temperatures and heat indices will not be quite as high on Thursday, but high heat stress will remain given little relief over the last several days.

Thunderstorm forecasting the past several days has been exhausting and incredibly difficult. No different today with a hot and humid airmass in place, fostering moderate to strong sfc based instability. Previous runs of the convective allowing models did show the potential for a very strong line of thunderstorms during the morning to midday hours, but given the lack of development across WI at this time, seems hard to see that coming to fruition, at least in the way/time that was previously thought. Based on the RAP progged fields, it does appear a convectively charged feature out of MN moves northeast within the southwest flow aloft, potentially aiding in some thunderstorm development mid afternoon into the evening. Not entirely confident on this potential overall, but there is a signal at least for the 4-6PM start time for strong to severe thunderstorm development, damaging winds and hail the main threats. Additional energy and thunderstorm complex inertia will make a run at northern MI tonight, and much like this past night, there is a chance for the activity to lose steam to some degree. That being said, tonight will feature the best chance for thunderstorm coverage. Any storm has the potential for heavy rain (strong instability and anomalous moisture), strong winds, and hail.

More or less a rinse and repeat on Thursday, with the evening and overnight the best potential for thunderstorms, a few strong. SPC's outlook has much of the region in a Marginal Risk (level 1 of 5) for severe thunderstorms, with a small sliver of a Slight Risk (level 2 of 5) near Manistee and vicinity, which is fair given the focus of convection being a little farther south. Rich moisture remains in place, so locally heavy rain on the table once again, along with the typical wind threat.

Better, more defined forcing arrives late week (although the exact positioning of the short wave/upper low is in question), and thus a more confident forecast in regards to thunderstorm coverage. There is at least a signal for areas of heavy rain showing up within the deterministic suite, but that will depend on the timing and longevity of the thunderstorms that will likely develop to our west. One would imagine strong winds would be the hazard, especially if an MCS moves in from the west. Moderate shear would also suggest hail is not impossible.

By this weekend, energy within the somewhat more zonal flow will keep the unsettled conditions around. That being said, temperatures will decrease with 80s most locations, with less humidity. High pressure develops over the Desert Southwest next week, looks like the monsoon convection is in full swing. Over northern Michigan, it remains warm as heights will be above normal.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 510 AM EDT Wed Jul 1 2026

Wouldn't be surprised to see some MVFR producing stratus develop after sunrise, with any low clouds quickly mixing out through the morning. Very low confidence forecast for the rest of the period owning to increasing uncertainty in thunderstorm evolution, organization, and timing. Tentatively appears best shot for most widespread activity holds off until later tonight. Will continue to run with VFR wording for now, unfortunately waiting for convective evolution for more specific impacts on the taf locations. Any storms that do develop could become locally severe, with gusty winds and very heavy rainfall. As previous forecaster mentioned, there definitely is potential for rapidly changing conditions and flight categories through the period.

APX WATCHES/WARNINGS/ADVISORIES

MI...Heat Advisory until 8 PM EDT Thursday for MIZ016>018-020>036- 041-042-097>099. MARINE...Small Craft Advisory from 4 PM this afternoon to 8 AM EDT Thursday for LMZ323-344-345. Small Craft Advisory from 2 AM to 8 AM EDT Thursday for LMZ341- 342. Small Craft Advisory from 4 PM this afternoon to 2 AM EDT Thursday for LMZ346.