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KEY MESSAGES

- Extreme Heat Warning this afternoon through tonight.

- Today's high temperatures reach or exceeding 100 in many places. Overnight temperatures are not expected to drop below the low to mid 70s near the Missouri River and south.

- Hot, dry, and windy conditions late Saturday and Sunday will create critical fire weather conditions.

- A stark cooldown across the region late Sunday and Monday.

DISCUSSION

WEATHER PATTERN OVERVIEW: An upper ridge over Montana will be flattened by an upper low that moves east from the Gulf of Alaska over the next several days. Southwest upper flow combined with prefrontal compressional heating will send the mercury above 100 for a lot of real estate from central to eastern Montana. Some locations likely to challenge daily high temperature records. An Excessive Heat Warning is in effect from noon today through noon Sunday for the western zones and till 6 pm Sunday for the eastern zones.

Increasing south winds will give rise to fire weather concerns as the sun shouldn/t have too many clouds to fight with. Only morning smoke would inhibit it and that should disperse during the day. A Red Flag Warning is in effect from 2 PM this afternoon to 9 PM MDT Sunday.

The strong upper low will send a couple cold fronts southeast across the area, the first one arriving about midnight tonight with the second pushing through Monday morning. Wind will signal their arrival as only small chances of brief showers are expected. A Lake Wind Advisory is effect tonight through Sunday that will likely need an extension through Monday.

After Monday, the upper trough moves east and a zonal flow succumbs a bit to a Desert southwest ridge by the end of the forecast cycle. Expect dry conditions with temperatures warming to near normal. Winds generally look light so Fire Weather issues should be minimal.

FORECAST CONFIDENCE & DEVIATIONS:

Base forecast elements were not changed as NBM seemed to be handling most elements well. However CAMS could provide more detail later today.

TFJ

AVIATION

UPDATED: 2230Z

FLIGHT CATEGORY: VFR

DISCUSSION: Clear skies are expected into tonight. Periods of mid level cumulus clouds will linger over eastern terminals. There is an isolated chance that KGGW visibility could drop into MVFR conditions from HAZE between about 03 to 15Z tonight.

WINDS: Southeast at 10 - 20 kts becoming west during the afternoon. Light and variable winds during the night.

DENSITY ALTITUDE: Will be a concern especially Saturday with temperatures near or over 100. Extra power and longer runway will be needed for takeoffs.

FIRE WEATHER

A hot day with very low humidity is expected today ahead of a cold front. A Red Flag Warning is in effect from 2 pm this afternoon to 9 PM Sunday. That is expected to move in late tonight. It will be cooler Sunday but the humidity will not be significantly lower while northwest winds will be significant. Cooler conditions with higher humidity is expected Monday. Winds are expected to be light Monday night with temperatures Tuesday morning in the 40s to around 50. Light winds are expected most of next week while temperatures slowly warm.

GGW WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning from noon Saturday to noon MDT Sunday for Central and Southeast Phillips-Central and Southern Valley- Garfield-Northern Phillips-Northern Valley-Petroleum-Southwest Phillips.

Red Flag Warning from 2 PM Saturday to 9 PM MDT Sunday for Dawson/McCone/Prairie/Richland/Wibaux Counties-Fort Peck Reservation and Daniels/Roosevelt/Sheridan Counties-Northern Valley and Northern Phillips Counties-Southern Petroleum and Southern Garfield Counties-The Little Rockies-The Lower Missouri River Breaks including the Charles M Russell National Wildlife Refuge.

Lake Wind Advisory from 6 PM Saturday to 6 PM MDT Sunday for Central and Southeast Phillips-Central and Southern Valley- Garfield-McCone-Petroleum.

Extreme Heat Warning from noon Saturday to 6 PM MDT Sunday for Daniels-Dawson-Eastern Roosevelt-McCone-Prairie-Richland- Sheridan-Western Roosevelt-Wibaux.