Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
636 FXUS65 KGGW 061107 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 507 AM MDT Mon May 6 2024 .DISCUSSION... KEY MESSAGES: - There is a High Wind Warning for much of the area for very strong winds today through Tuesday night, leading to crosswind concerns on area roadways and dangerous chop on Fort Peck Lake. - Widespread rain today through Wednesday night. Weather Prediction Center has issued a Slight Risk for Excessive Rainfall for the 24 hr period ending on 6am Tuesday. - Flood concerns increasing for small streams Tuesday and Wednesday, leading to rises along the Milk River late in the week. WEATHER PATTERN OVERVIEW: A stacked low pressure system will lift from the central Rockies into the northern Plains today, then linger over the region through Tuesday night. The low will then begin to drift southeast as a latitudinal ridge folds south toward the Canadian border through the end of the week. By the weekend a flat ridge will push from the Pacific Northwest across the northern Rockies. CONFIDENCE AND POTENTIAL DEVIATIONS FROM BASE FORECAST: Probabilities for high wind have decreased slightly with both speed and area. Still looking at high probability (70-90%) for wind gusts over 55 mph for Phillips county (excluding the north), Petroleum and Garfield counties. For Prairie county the high winds will be mostly in the west over the Big Sheeps, and Valley county will see the strongest winds across the ridge tops near Fort Peck Lake. So have upgraded these zones to a High Wind Warning. Other zones in the watch will have much lower probability for reaching high wind criteria, so cancelled that portion of the watch. Rainfall amounts for the region from today through Wednesday night remain very high. Probability for at least 1 inch is over 70% for the entire region. Confidence for 2 inches or more drops off to 30-50% east of Opheim, Poplar and Glendive while staying at 60-90% for most of the area to the west. Probability for more then 3 inches is not insignificant, setting at 30-40% for Malta, Glasgow and Jordan, and peaking at 60% around the Little Rockies. With the widespread high precipitation amounts, flooding will become a concern from midweek into the weekend. RFC forecasts are putting the Milk River at Tampico and Glasgow above flood stage by the end of the week. Small stream flooding and impassable gravel roads are also expected mainly for Phillips, Valley and Garfield counties. && .AVIATION... VFR, dropping to IFR as showers move north through the day. Low clouds and occasional reduced visibility will linger through Tuesday as a low pressure system keeps rain over the region. With the low pressure, winds will be turning from east to northwest throughout the day, and increasing to 20-30kts with gusts to 40kts after 0z Tuesday. && .GGW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 9 AM this morning to midnight MDT Tuesday night for Central and Southeast Phillips-Central and Southern Valley-Garfield-Petroleum-Prairie-Southwest Phillips. && $$ weather.gov/glasgow