textproduct: Gaylord

KEY MESSAGES

- Increasingly hot and humid next week with periodic thunderstorm chances.

DISCUSSION

Issued at 148 AM EDT Sat Jun 27 2026

Pattern Synopsis and Forecast:

Quiet and uneventful weather (outside of any fog, especially this morning) will persist through the remainder of the weekend as sprawling surface high pressure remains largely in control, promoting slowly moderating temperatures under mostly clear skies. As we transition into next week, a highly anomalous heat dome, characterized by 597 decameter mid level heights, will intensify across the Southeast and Ohio Valley before steadily building northward into the Great Lakes region. Consequently, an extended period of unseasonably hot and humid conditions is expected to materialize, with the most oppressive heat index values likely concentrating between Tuesday and Thursday. The most obvious fail point for reaching our absolute maximum temperature potential will be the introduction of organized convection or thick convective debris clouds radiating from upstream complexes, which would act to significantly limit daytime insolation. Regardless of the exact high temperatures, a steady surge in low-level moisture will ensure that humidity increases noticeably. The latest LREF guidance is firmly on board with this synoptic evolution, projecting widespread upper 80s to mid 90s across the interior for the Tuesday through Thursday timeframe. This represents a pretty significant and consistent signal from the global ensemble models, and given the setup, upper 90s not out of the question near Saginaw Bay. While mesoscale details remain to be determined, the overarching pattern supports a several days of hot and humid weather next week.

Alongside the building heat, expect plenty of thermodynamic instability to pool across the region next week. Beginning on Monday, precipitable water values are forecast to surge well above climatological norms, accompanied by surface dewpoints reaching into the 90s and occasionally tapping into the lower 70s. Because northern Michigan will reside directly on the northern periphery of the expanding upper-level ridge, we will be susceptible to ridge riding short waves. Therefore, we will have to closely monitor the evolution of upstream convection to our west, which could propagate eastward into our area in some fashion. Right now, the best potential for showers and storms appears to be later Sunday into Monday, coinciding with the initial surge of northward moisture, followed by another window later Tuesday, and then periodically later in the week. The inherent subtleties of this pattern, combined with heavy mesoscale dependence regarding boundary interaction and residual cloud cover, will undoubtedly make for a tricky forecast. Pining down exact storm coverage and isolating any localized severe weather threats will be challenging at this lead time, so we will continue to monitor the upcoming pattern closely.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 118 PM EDT Sat Jun 27 2026

High confidence VFR conditions through the period. Skies generally FEW-SCT AOA 4kft. Generally light winds (AOB 10kts) with VRB directions due to local lake breeze interactions continuing through 00z. Mostly clear skies overnight with low chances for patchy BR development due to high clouds. E/SE winds of 5 to 10kts near the end of the period.

APX WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.