Area Forecast Discussion

KEY MESSAGES

- Winds diminish this evening then temporarily increase late Friday. - Cooler than normal conditions are expected to continue. Saturday night expected to be the coolest night.

DISCUSSION

WEATHER PATTERN OVERVIEW: With an upper low over south-central Canada, the upper flow over northeast Montana this afternoon was northwest. This is making for another windy day across the area with wind gusts around 40 mph.

Daytime heating and sufficient humidity allowed for cumulus clouds to develop but showers have been isolated with the dewpoints mostly in the 40s (noted that the showers were more numerous over southern Sask and western ND with dewpoints in the 50s).

Activity will diminish by evening with loss of daytime heating but a disturbance will keep showers going across central Montana and into the western zones tonight. A Lake Wind Advisory expiring at 9 pm looks good.

Winds pick up again Friday with a Lake Wind Advisory likely needed for the afternoon. Cumulus will build again and produce isolated showers.

Saturday should feature the coolest day with highs in the 60s and lows the following night mainly in the 40s, but some 30s are possible in some of the cooler valleys.

Things begin to warm a bit Sunday through Tuesday but a couple disturbances look to drop southeast in the region. This will bring the chance of showers and isolated thunderstorms.

FORECAST CONFIDENCE & DEVIATIONS:

Confidence then remains above average for cool and unsettled weather to continue for next several days given the NW flow continuing. Confidence in exact timing, placement, and amount of precipitation remains low to moderate given the mesoscale detail still to be worked out a larger time scales.

Therefore, used CAMS and NBM for shower chances through Friday. Used the default NBM for the remainder of the forecast. TFJ

AVIATION

UPDATED: 2030Z/2:30 PM

FLIGHT CAT RANGE: VFR.

DISCUSSION: Afternoon cumulus clouds with scattered showers should diminish to isolated showers this evening with the best chance near KGGW and KOLF. Afternoon scattered showers develop again Friday so bumpy rides ahead.

WINDS: W-NW winds finally diminish this evening but increase Friday with similar speeds to today during the afternoon, 10-20 kts with gusts to 25-30 kts. TFJ

GGW WATCHES / WARNINGS / ADVISORIES

Lake Wind Advisory until 9 PM MDT this evening for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum.