924 FXUS65 KTFX 080258 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 858 PM MDT Mon Apr 7 2025 .KEY MESSAGES... - Pacific cold front moves across the region this evening, accompanied by locally windy conditions, scattered showers and a perhaps an isolated thunderstorm. - Periods of windy conditions persist through Wednesday with with locally stronger winds possible near areas adjacent to the Rocky Mountain Front. - Drier and milder conditions redevelop Thursday and Friday before the next Pacific upper trough begins to move into the area for the weekend. && .UPDATE... No major changes were made with this evening`s update. Ludwig && .DISCUSSION... /Issued 529 PM MDT Mon Apr 7 2025/ - Meteorological Overview: The upper ridge axis shifts east of MT tonight as an upper level trough in the eastern Pacific broadens to the north a of fairly potent (for April) Pacific upper level jet moving east between 40- 45N. The lead shortwave moving out of the trough Lifts out into southern AB tonight while a Pacific cold front at the surface sweeps east across north-central and southwest MT late this afternoon and evening. A period of steadier precipitation with and following the frontal passage will mainly be focused along areas of the continental divide north of the Lincoln to the Canadian border, while showers accompany front as it moves through areas to the east and southeast. Drying affects in westerly flow over the Rockies will limit the coverage of showers to isolated at best over the Golden Triangle portion of north-central MT. Showers will be more numerous across southwest MT this evening, where enough weak instability may be present for an isolated thunderstorm. Wind is likely to be the more noticeable affect of the front at most locations with a shift to gusty west winds occurring with its passage and gusty winds persisting through most of tonight and tomorrow across the N-central MT plains. A period of stronger winds is likely to develop across western portions of north- central MT late tonight through Thursday morning as a second embedded shortwave disturbance tracks from NW MT into southern AB with an associated 700mb wind maximum. Snow levels lower to 5000-6000ft along the continental divide late tonight and lower to less than 5000ft Tuesday morning, but the intermittent nature of snow showers and air/road temperatures only marginally near freezing will limit the potential for snow accumulation on road surfaces. Weaker disturbances moving through fast/moist westerly flow will bring additional rounds of rain/snow showers through Wednesday, primarily focused along the continental divide and parts of southwest MT. - Forecast Confidence & Scenarios: Afternoon/Evening Showers and Isolated Thunder: Aside from the small (<10%) risk for lightning through early this evening, the convective nature of showers in SW and central MT this evening and initially dry low levels could bring some stronger wind gusts down in their vicinity. Strong Wind Potential Tuesday: As the shortwave and surface low pressure emerge in southern AB Tuesday morning, a period of more favorable condtions for mountian wave wind enhancement could allow wind gusts in excess of 55 mph to expand from the Northern Rocky Mtn Front to as far east Cut Bank and eastern Glacier county. Longer Range Outlook: Warmer and drier conditions are on track to re-develop by Thursday and Friday as a transient upper level ridge briefly amplifies across the Northern Rockies. Looking ahead to the weekend and beyond, there is reasonable agreement among longer range model ensembles for upper upper level troughing in the vicinity and a transition back to cooler and active weather. There still is a great deal of uncertainty with the timing and other important details of the troughing, but it is worth noting that a small subset of longer range ensemble members (10-20%) continue to support a spring-storm scenario with more significant precipitation. Hoenisch && .AVIATION... 08/00Z TAF Period A Pacific trough and attendant cold front will bring isolated shower activity and perhaps a rumble of thunder this evening followed by additional showers and some mountain snow tonight into Tuesday. Most of this activity will be concentrated along the Continental Divide and over Southwest Montana. VFR conditions are generally expected, but there will be passing mid- and higher level clouds and mountains will be obscured, especially during times of precipitation. Most locations will see winds diminish some tonight except along the Rocky Mountain Front where mountain wave activity will maintain windy conditions. Cold air advection aloft and diurnal mixing will increase winds to the 20 to 40kt range for most locations on Tuesday, with gusts approaching 50 kts at times in the KCTB area. - RCG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 40 56 36 57 / 20 10 0 10 CTB 36 51 34 53 / 10 10 0 10 HLN 37 56 36 57 / 40 20 10 10 BZN 35 54 31 55 / 40 40 10 20 WYS 30 48 23 50 / 70 70 40 10 DLN 36 54 32 55 / 30 20 10 0 HVR 39 59 34 60 / 10 10 10 10 LWT 38 54 34 52 / 30 20 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls