Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
312 FXUS65 KMSO 260753 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 153 AM MDT Sun May 26 2024 .DISCUSSION...Satellite imagery early this morning shows a weak circulation moving through southwest Montana. As this system moves east, high pressure will build in its wake and strengthen through the remainder of the Memorial Day weekend. Expect decreasing clouds and fair weather across the Northern Rockies into Tuesday morning as the ridge amplifies over the northwestern U.S. As the ridge strengthens, daytime high temperatures will increase through Tuesday. Model ensembles show daytime highs exceeding 80 degrees (greater than 90 percent chance) for the valleys of west-central Montana and the lower valleys in north- central Idaho. An increase in moisture will accompany warm temperatures on Tuesday under southwest flow aloft. A less stable atmosphere, along with ample shear, will create a good environment for thunderstorms capable of producing strong outflow winds, brief heavy rain, and small hail. The geographic focus for convection will be across Idaho and northern Lemhi Counties in Idaho and western Montana south of about I-90. Forecast confidence decreases Wednesday into Thursday next week. Guidance is struggling with the amplitude and track of the aforementioned Pacific trough as it moves eastward. Roughly 40% of solutions suggest the trough will deepen into a closed low, with widespread precipitation and another round of snow across southwest MT and the higher elevations in ID, while the other members portray a weaker trough with higher snow levels and less precipitation. && .AVIATION...Precipitation will come to an end this morning across the Northern Rockies airspace. Today, westerly winds will be increasing by late morning or early afternoon. Expect gusts of about 20 to 30 knots, especially at KBTM and KMSO, to last until about 27/0300Z. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$