{ "number": 970, "headline": "June 29, 2026 Monday Mega Heat Dome", "standfirst": "Forecasts trending hotter across the Big Cities of the Eastern Seaboard with 100\u00b0F+ likely for 71 million Americans into 4th of July weekend", "desk": "record", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2026-06-30", "published": "2026-06-30T01:36:46.057000Z", "updated": null, "access": "free", "body_html": "
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The main weather story this week continues to be the \u201cMega Heat Dome\u201d forming across the Eastern United States.

High Temperatures next 8-days \u2014 watching the population of at least 90\u00b0F + 100\u00b0F skyrocketing as the large population centers of the East Coast see extreme heat wave for multiple days.

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This is forecast post number 970: Day 180 of 2026. Day 29 of Atlantic Hurricane Season \u2014 very quiet with building El Ni\u00f1o \u2014 but the Western Pacific basin is about to uncork a powerhouse Super Typhoon

Author: Dr. Ryan Maue (X @RyanWeather X @weathertrader)

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Upper-Level Height Anomaly | AIFS-Single Next 10-days

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While very strong troughing digs into the Pacific Northwest = much cooler air across the West, a major ridge forms over NE Arctic Canada and extends down an axis into the U.S. Southeast forming the heat dome.

Ridging builds across the Eastern U.S. \u2014> dry and hot \u2014> HEAT DOME

Into Summer \u2014> Height Anomalies don\u2019t tell entire story \u2026 actual height does!

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5940 m height contours \u2014 not quite record level near 6000 m but plenty of subsidence to ensure very hot surface temperatures. We\u2019re entering the \u201cdog days of summer\u201d when the weather pattern stagnates with long-lasting, slow moving ridges.

NWS Precipitation Next 72-hours \u2014> Thursday Afternoon

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Nice to see South Florida with heavy rain from the easterly flow around the bottom periphery of the \u201cheat dome\u201d

My favorite parameter \u2014 next 48-hours of HRRR Precipitable Water

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Weather Into Tuesday Morning

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HRRR radar next 18-hours through Tuesday Noon ET

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HRRR Next 48-hours simulated Radar through Wednesday 2 PM ET

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Weather on Tuesday

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Blend of Models \u2014> Precipitation Next 7-days

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Flagship model: ECMWF AIFS 18z \u2014> Integrated Vapor Transport next 10-days

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Heat dome shuts down the Gulf of Mexico. Looks like a much drier than normal period ahead for the next 10-14 days to start July.

Germany ICON 18z | Precipitable Water | My Favorite Parameter

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Tropical system off the Southeast coast has a nice blob of 2\u201d+ PWAT and maybe become a nice tropical depression or storm for Georgia / North Florida / South Carolina = rainfall and clouds to break the \u201cheat dome\u201d

Temperature Analysis | RTMA | 7:45 PM ET

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About 78 million population at least 90\u00b0F at 7:45 PM ET

Temperature Anomaly | RTMA | 7:45 PM ET

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Lower 48 was -1.3\u00b0F below normal with chilly temperatures (relative to last days of June) across the Pacific Northwest and Northern Rockies

Heat Index Temperature | RTMA | 7:45 PM ET

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100s into the Great Lakes

High Temperatures Next 9-Days \u2014> Wednesday July 8th

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Northeast Regional Zoom

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Washington D.C. hottest on Friday with 105\u00b0F (very hot)

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NYC Central Park at 102\u00b0F on Thursday and Friday, and 100\u00b0F on Saturday, July 4th

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Boston to 100\u00b0F on Thursday

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Low Temperatures on Tuesday

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Muggy with lows in the mid-70s into Great Lakes

High Temperatures on Tuesday

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233 Million at least 90\u00b0F

ECMWF Flagship Ensemble Mean Temperature Anomaly next 15-days

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Trough \u2014> cooler across the Pacific Northwest with huge negative anomalies of -20\u00b0F vs. the formation of a ridge / heat dome across the Great Lakes and into the Mid-Atlantic + Canada

Week 1 \u2014> June 29 to July 5

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Week 2 \u2014> July 6 to July 12

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Tropical Update: Atlantic Basin \u2014 (15-day tracks forecast from EPS 12z)

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This disturbance (10%) is not being picked up by my storm tracker, but the minimum sea level pressure might be too high against the background environment of Bermuda High

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Western Pacific lights up with 2+ Typhoons likely with long-tracks = huge ACE

Next names are Bavi & Maysak

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Invest 95W will become a MONSTER. I would not be surprised to see Category 5 \u2014 155 knots (T 7.5) or higher

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My Atlantic Hurricane Season Forecast (2026)

From April 7, 2026: Atlantic Seasonal Hurricane Forecast: (11/5/2)

9-13 Named Storms (11 most likely)
4-7 Hurricanes (5 or 6 most likely)
1-3 Major Hurricanes (2 most likely)
Accumulated Cyclone Energy: 75-85 (well below normal)

NOAA 2026 Atlantic Hurricane Season Forecast

More details in Thursday, May 21, 2026 Tropical Update

", "body_key": null, "teaser_html": "

The main weather story this week continues to be the \u201cMega Heat Dome\u201d forming across the Eastern United States.

High Temperatures next 8-days \u2014 watching the population of at least 90\u00b0F + 100\u00b0F skyrocketing as the large population centers of the East Coast see extreme heat wave for multiple days.

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