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KEY MESSAGES

- Dangerous heat and humidity are expected to cause impacts to northeast Montana this weekend. Highs will be in the 90s and 100s with lows in the mid 60s to low 70s.

- Hot and dry weather and breezy conditions will lead to near critican fire weather concerns for Sunday afternoon, but recent precipitation and green fuels may limit the extent of the risk. - Temperatures will moderate early next week, but are expected to remain above average.

DISCUSSION

WEATHER PATTERN OVERVIEW:

A large upper ridge over the western U.S. will become firmly established over the weekend. This will lead to mainly dry and hot weather conditions with the Extreme Heat Watch continuing for the period. Highs on Saturday and Sunday will reach into the 90s and 100s with lows in the 60s and 70s. In addition, this heat wave will be more humid than usual, especially in the northeastern zones where dew points may remain in the 60s. These prolonged conditions may raise risk for heat related illnesses.

Additionally, ensemble guidance is pointing to breezy conditions Sunday afternoon with southeast wind gusts potentially greater than 30 mph. If this comes to fruition in the presence of humidity in the teens and 20s, near critical fire weather conditions may emerge for parts of the area. Recent precipitation and green fuels may limit the overall extent of the risk, but this period remains worth monitoring.

While conditions will moderate some and precipitation chances will return next week, overall temperatures will remain near to above normal for this time of year, and heat stresses could last well into next week, especially for sensitive groups.

FORECAST CONFIDENCE & DEVIATIONS:

Minor adjustments to pops and humidity for the short term period were made for collaboration with neighbors and consistency. Otherwise NBM was left untouched. Ensembles are in line with good consensus for the hot and dry weather this weekend with above average confidence. Even if forecast maximums come in below expectations, the humid air mass would offset that moderation. Additionally, the combination of hot and humid conditions with little overnight recovery leave enough justification to keep the messaging going.

AVIATION

UPDATED: Thursday July 9 at 1800Z

FLIGHT CATEGORY: VFR

DISCUSSION: Mainly dry weather is expected over the taf cycle as upper ridging begins to gain an influence. Hot temperatures with highs above 100 degrees this weekend may lead to equipment issues.

WIND: Northwest winds will range from 5 to 15 kts this afternoon, becoming light and variable after 03Z.

GGW WATCHES/WARNINGS/ADVISORIES

Extreme Heat Watch from Saturday morning through late Sunday night for Central and Southeast Phillips-Central and Southern Valley-Daniels-Dawson-Eastern Roosevelt-Garfield-McCone-Northern Phillips-Northern Valley-Petroleum-Prairie-Richland-Sheridan- Southwest Phillips-Western Roosevelt-Wibaux.