textproduct: Glasgow

KEY MESSAGES

- A warming trend will continue through Memorial Day Weekend. Highs could be approaching 100 degrees in some locations on Tuesday. - Hot temperatures, low humidity will raise fire weather concerns for Monday and especially Tuesday when gusty southeast winds develop.

- Scattered thunderstorms are expected by Tuesday evening moving in from west to east, with an isolated stronger storm possible. Storm chance will then ramp up each afternoon into the weekend.

DISCUSSION

WEATHER PATTERN OVERVIEW: Upper ridging will continue to advance from the west over Memorial Day Weekend. Look for progressively warmer and even hotter daytime temperatures along with very dry afternoon relative humidity each day. High temperatures by Memorial Day will be well into the upper 80s to mid 90s for most of NE Montana while relative humidity reaches as low as 12 to 15 percent. However, wind is expected to be light during this time which will probably prevent Red Flag conditions.

On Tuesday as the ridge slides over to the east, low level southeast winds will ramp up to much stronger conditions, with high temperatures in the 90s and humidity readings between 10 and 20 percent. This combination in the presence of dry fuels may lead to fire concerns. Even where green up is underway, curing may take place from consecutive hot and dry weather days. Gusty southeast winds may also present boating hazards for Fort Peck Lake.

On Tuesday evening, an upper trough will move in from the west while thunderstorms will across central Montana. These storms will make progress eastward into NE Montana. An isolated stronger thunderstorm is certainly possible, with the greatest coverage expected to be for areas west of a line through OPheim to Glasgow to Jordan.

Wednesday onward: Ridge will remain just to the east with southern flow pattern across the west. While temps will come down a little each day, PWATs are expected to rise from 0.50" to 1.00" rapidly and then slowly to 1.10" by Friday. This will allow plenty of moisture to get pulled into the region with thunderstorms starting each afternoon over the central Montana mountains. These will then move off over eastern Montana with a chance for severe weather each afternoon and evening.

FORECAST CONFIDENCE & DEVIATIONS: No deviations to NBM were observed.

Confidence is MODERATE to HIGH that the culmination of hot, dry, and windy conditions along with drying fuels may present fire weather concerns by Tuesday.

Confidence is MODERATE in thunderstorms each afternoon from Wednesday through the weekend.

GAH

AVIATION

LAST UPDATED: 0330Z.

FLIGHT CAT RANGE: VFR.

DISCUSSION: Excellent flying weather with mid to high clouds moving across the terminals.

WIND: Light and variable tonight, becoming west at 5 to 15 kts on Sunday.

EQUIPMENT: KSDY obs are unavailable and will be AMD NOT SKED.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

None.