Friday Morning Weather Summary

June 26, 2026 11:28 UTC

- The upcoming heat wave will peak during days 5-8 across the Midwest and East with major heat for some at the peak
- The forecast trended warmer across the Northeast/Mid-Atlantic during days 6-8 and cooler across the West in general today. Storms will be active in the Midwest

Heavy rain/storms will be a threat today into tonight from northeastern OK through a chunk of the OH Valley along a front. Flooding will be a risk. Rain/storms will impact the Mid-Atlantic into the TN Valley on Saturday. Severe storms and locally heavy rain will be a risk. The cooler pattern across the Midwest will end after Saturday. A big warm up will begin across most of the Central/Eastern US during days 3-5. The greatest anomalies will impact the Upper Midwest/Great Lakes. The Gulf Coast won't participate in the heat. To the west, a significant cold shot will impact the West, notably the northern Rockies/Great Basin, during days 2-5. It will be cold enough for mountain snow in the northern Rockies this weekend. The contrast between air masses will create severe weather risks across the northern Plains/Upper Midwest Saturday into early next week.

The heat wave in the Central/Eastern US will persist through day 8, notably across the Midwest through the Northeast. The guidance trended warmer across the Northeast and Mid-Atlantic and temperatures were warmed toward the warmer end of guidance. Below normal temperatures will persist across the West. The end of the period will see a gradual westward shift of warm anomalies as the upper ridge responsible for the heat wave shifts westward. Guidance trended less warm across the North Central US, but this didn't require significant change to account for. Temperatures had to be cooled in the West as the warm up trended slower over the last 24 hours. Scattered thunderstorm clusters could present cool risks at times across the Upper Midwest/Great Lakes.

The MJO will push through phase 6 during the day 11-15 period, which will help push the ridge into the Rockies and form a trough along the East Coast. Above normal temperatures will shift to the West. However, most guidance may be too warm in the Pacific Northwest. The AIFS guidance is cooler. Readings had to be cooled. The ECMWF is warmer across the Midwest and Northeast because its MJO forecast is weaker than other guidance. That said, the cooler GEFS trended a little warmer. Temperatures were raised, but the GEFS is still favored.

Friday Morning Model Summary

June 26, 2026 09:59 UTC

Most guidance trended warmer across the Mid-Atlantic and Northeast US during the day 6-10 period, especially during the peak 1-2 days of the upcoming heat wave. Temperatures will be raised as a result. Meanwhile, guidance shifted less warm across the North Central US during the day 7-10 period. This was a minor change. This won't require much change, maybe a degree or two here and there, to accommodate. Guidance trended cooler along the West Coast since 0Z yesterday. The 0Z runs overnight stabilized the trend. Some cooling will be necessary. Guidance trended warmer across the southern High Plains during most of week 2 and temperatures will be raised in those areas. The GEFS trended warmer in the Midwest/East during days 11-15. This won't require much change. The ECMWF trended cooler in the Northwest US and some cooling will occur.

Thursday Midday Update

June 25, 2026 18:24 UTC

- A surge of summer heat will engulf the Midwest/Great Lakes throughout much of the 5-10 day period
- Hot and humid conditions will work into the East by the 7-10 day period, peaking on days 8-9. Warmth should shift back towards the Interior West by the 11-15 day period

A complex of rain/storms will move across eastern KS into MO this afternoon into tonight. The main rain/storm threat should shift towards central IL and IN on Friday before reaching OH and the northern Mid-Atlantic Friday night into Saturday. Heavy rain producing flash flood risks will be the primary concern, but there will be a risk for a few embedded severe storms as well. A more active pattern will emerge this weekend across the Northern Plains, with multiple rounds of showers and storms expected. A trough will become stationed across the West, bringing a surge of below normal temperatures to the region over days 2-5. Waves of showers will also impact the Northwest during much of the 2-5 day period. Cooler readings will linger into Friday across much of the Midwest. Ridging will become established across the Midwest over days 3-5, providing a major warmup across the region, especially by Monday. Highs should reach the middle-to-upper 90s in Chicago and Minneapolis on Monday. Above normal temperatures are generally favored across the Southern Plains through the Southeast over days 2-5, while more seasonable temperatures are expected in the Northeast.

Sustained summer heat will be in place over the 6-10 day period from the Upper MS Valley through the Great Lakes/OH Valley and to the Appalachians. Highs in the middle-to-upper 90s will be common in and around the Great Lakes through day 8 before some moderation should occur by days 9-10. The warmup should be shorter in duration along the immediate East Coast, but highs along the I-95 Urban Corridor should still peak in the 90s on days 8-9, and Philadelphia/Washington D.C. could threaten 100 degrees. Less potent warm anomalies should extend through the Gulf Coast through the 6-10 day period. The cooler pattern in the West should hold through next Thursday before abating over days 9-10. Rounds of scattered showers and thunderstorms will impact the Upper Midwest much of next week, which will create some cool risks for locations impacted by storms.

Upper-level ridging should retrograde from the Midwest towards the Interior West during days 11-15 as the MJO reaches phase 6. This should allow for more seasonable temperatures to return to the East/South. Summer heat will ease over the course of the period across the Midwest, while increasing warmth is anticipated across the West, especially the Interior Northwest.

Thursday's Quick Midday Update

June 25, 2026 17:07 UTC

The 12Z GFS came in less cool during the 6-10 day period across CA through the Great Basin and into OR, especially by days 9-10. The Central and Southern Plains trended a bit warmer over days 8-10. New England came in considerably cooler over the 6-10 day period, with a more modest reduction of warmth extending towards the Mid-Atlantic Coast by the 8-10 day period. The OH Valley was warmer on day 6 as well as on days 9-10. During the 11-15 day period, the 12Z GFS was considerably warmer across the Northeast and the northern Mid-Atlantic. The new GFS was warmer for the 11-15 day period across the Rockies. The West Coast came in warmer on day 11 before trending less warm over days 12-15. The Northern and Central Plains trended less warm on day 11 before coming in warmer over the 12-15 day period. The Southern Plains were warmer for days 11-15.