Weather for New England and the Northeast

Area Forecast Discussion
National Weather Service Gray ME
222 PM EDT Wed Jul 8 2026

**What has Changed**
Confidence has increased that southeastern New Hampshire is going to see heat index values greater than 95 degrees Thursday afternoon. A Heat Advisory has been issued accordingly.

**Key Messages**

1. Heat and humidity build Thursday, lasting through Friday before a slow moving front brings cooler and drier air by late Friday night.
2. A couple of weak cold fronts bring a chance of thunderstorms on both Thursday and Friday afternoons and evenings. Some of these could be strong to severe.
3. Mostly dry with seasonable temperatures this weekend with a warming trend possible during the early to middle part of next week.

**Discussion**
The latest model guidance is all in good agreement on warm and sticky weather beginning Thursday as temperatures about 5000 feet above the surface, known as 850 millibar temperatures, climb significantly to between 61 and 64 degrees Fahrenheit under a low amplitude ridge, which is an elongated area of calm, warm air. This weather pattern will be quickly swinging through the region.

This supports surface temperatures in the upper 80s to 90 degrees. Southwesterly air flow will provide an extra boost to valley locations, which may push them more toward 91 to 92 degrees via downsloping, a process where air warms up as it moves down the side of mountains.

The southwesterly winds are also going to bring elevated dewpoints, a measure of atmospheric moisture, into the middle to upper 60s. This moisture will push heat indices up above 90 degrees in many locations. The southern New Hampshire portion of the Merrimack Valley may even see heat index values in the 95 degrees plus range, so meteorologists have gone ahead with a Heat Advisory for Eastern Hillsborough and Interior Rockingham.

The typical afternoon sea breeze likely gets kept at bay by the stronger land winds, so these warm temperatures should be realized right down to the coast. For areas north of the mountains, the front looks to begin to sag south of the International Border, bringing increased cloud cover and showers or storms. This stunts the warming potential, limiting these northern locations to the low to mid 80s.

As the front continues to sink southward Friday, cooler and drier air will be moving in behind it. As of now, areas north of the mountains stand the best chance of seeing a more pleasant day with highs in the mid to upper 70s and dewpoints down into the upper 50s and low 60s. South of the mountains, the warmer air mass of around 63 degrees Fahrenheit lingers around 5000 feet in southern zones, so those locations are likely to see another day with temperatures climbing into the upper 80s to 90 degrees.

Elevated dewpoints linger too, but with temperatures a little bit lower on Friday, heat indices should be lower as well. Computer guidance is still struggling slightly with the exact timing of the front, but it looks like by late Friday night most locations should be seeing the relief with low temperatures dropping into the 50s and 60s.

In addition to the heat and humidity, a couple of weak cold fronts will also bring chances for showers and thunderstorms during the afternoon to early evening hours each day for Thursday and Friday.

For Thursday, the higher overall chances for storms will be across the north in closer proximity to the cold front itself. Some of these could be strong to severe with 35 to 40 miles per hour of effective shear, which is a measure of how wind speed and direction change with height, helping to organize storms.

Atmospheric data shows around 500 Joules per kilogram of most unstable convective available potential energy, or MUCAPE, which represents the raw fuel available for storms. This comes from the High Resolution Ensemble Forecast, or HREF, which is a collection of several high resolution computer models averaged together.

Farther south, instability is forecast to be higher, in the 1000 to 1500 Joules per kilogram range, but storm coverage may be more limited because of lesser atmospheric forcing to kick off the storms, lesser wind shear, and some dry air aloft. However, if storms do develop in southern areas, they may carry more of a wind threat. This is because the dry air aloft can cause water droplets to evaporate rapidly, creating cooler, heavier air that rushes downward. This process enhances the downdraft convective available potential energy, or DCAPE, leading to strong wind gusts.

Precipitable water values, or PWATs, which measure the total amount of moisture in an atmospheric column, are climbing over 1.50 inches. This combined with deep warm cloud depths will support highly efficient rain rates. Because the atmospheric flow is moving roughly parallel to the frontal boundary, meteorologists will have to monitor for a localized flash flood risk if training can set up, which happens when multiple storms move repeatedly over the exact same area like boxcars on a train. This threat lines up well with a Marginal Risk for Excessive Rainfall issued by the Weather Prediction Center, or WPC, in and around the mountains.

Most computer guidance has this initial front pushing offshore Friday morning with a secondary front approaching later in the day. Lift from this second front should again allow showers and storms to develop in the afternoon. The latest midday computer guidance does not look to bring quite as much instability, but there still may be enough for a couple of strong to severe storms since the wind shear parameters look fairly similar to Thursday. The higher potential for strong storms looks to be south of the mountains this time around.

Surface high pressure, an area of sinking air that brings clearer skies, builds toward New England over the weekend. However, a 500 millibar shortwave, which is a small ripple or disturbance in the upper atmospheric flow, may provide enough lift for a few scattered showers on Saturday. Otherwise, dry conditions are forecast with fairly seasonable temperatures in the 80s.

For the early to middle part of next week, there is high confidence in a strong ridge of high pressure becoming centered over the Central and Northern Plains and into the Great Lakes.

Some expansion of this ridge is possible toward the Northeast to bring a warming trend, but New England also may remain more on the eastern edge of this system. Remaining on the edge could bring occasional chances of showers and storms, often called ridge rollers as they ride along the perimeter of the high pressure, along with more cloud cover.