textproduct: Glasgow

KEY MESSAGES

- Wednesday will feature another hot day across the area, in particular along the Yellowstone River Valley where highs will be around 100 degrees.

- Isolated to widely scattered thunderstorms will be possible at times for Wednesday.

- Upper ridging will remain in control for the second half of the week with above average temperatures likely to continue.

DISCUSSION

WEATHER PATTERN OVERVIEW:

Early morning thunderstorms will continue to lift northeast with the potential for heavy rain and strong wind gusts. During the day Wednesday additional isolated or widely scattered general thunderstorms are expected at times. Otherwise the main story will be the continued heat, especially from the Terry to Sidney corridor where highs will once again push 100 degrees. WIll keep heat related products in place for these areas. The Lake Wind Advisory will also continue for Fort Peck Lake but latest expected trends do suggest diminishing wind speeds late in the day.

Thursday into this weekend, look for a general rebound of upper ridging over the region extending into eastern Montana. Thus will mean a continuation of temperatures near to above average. Embedded shortwaves will keep thunderstorm chances in the forecast at times, but the predictability of specific timing and placement will be difficult at larger time scales.

FORECAST CONFIDENCE & DEVIATIONS:

NBM was utilized for this forecast cycle which captured expected big picture trends well. Confidence is high on continued above average temperatures but there will be low predictability of thunderstorms at times for the second half of the week into the weekend. As high resolution model data are available, near term tweaks to pops may better reflect expected convective behavior for each particular event.

AVIATION

UPDATED: Wednesday July 15 at 0445Z.

FLIGHT CATEGORY: VFR will prevail, look for MVFR to IFR any thunderstorms.

DISCUSSION: VFR will tend to prevail for Wednesday but thunderstorms at times today may result in visibility down to IFR.

WIND: E to NE at 10 to 20 kts, gusting to 30 kts. Look for winds to diminish to 10 to 15 kts after 00Z.

GGW WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 2 AM MDT Wednesday for Central and Southeast Phillips-Central and Southern Valley-Eastern Roosevelt-Garfield- McCone-Northern Phillips-Northern Valley-Petroleum-Southwest Phillips-Western Roosevelt.

Lake Wind Advisory until noon MDT Wednesday for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum.

Flood Watch until 6 AM MDT Wednesday for Central and Southeast Phillips-Petroleum-Southwest Phillips.

Extreme Heat Warning until 2 AM MDT Thursday for Dawson-Prairie- Richland-Wibaux.