Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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236 FXUS65 KTFX 090548 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1148 PM MDT Sat Jun 8 2024 Aviation Section Updated .SYNOPSIS... After a dry but slightly breezy day across the area today, showers and thunderstorms will develop across Southwestern Montana on Sunday, bringing a few strong wind gusts and localized heavy rain to the area. The week will start out a bit on the breezy side, but building upper level ridging will lead to a warm and dry second half of the week. && .UPDATE... No adjustments were made to the forecast tonight beside lowering overnight minimum temperatures a tad bit due to some radiational cooling in the Southwest Valleys. Other than that, the forecast remains on track. -Wilson && .AVIATION... 09/06z TAF Period VFR conditions continue through the beginning of the TAF period with conditions having potential to degrade across Southwest Montana late Sunday afternoon through the overnight hours Sunday. Thunderstorms are likely to develop between the 09/20z and 10/06z period for Southwest Montana airfields, but quickly move through with some lingering rain showers behind the storms. Primary concerns for any developed thunderstorm is lightning, gusty winds, small sized hail, and a brief heavy downpour that can lower visibility. KBZN will need to be monitored for low forecasted ceilings after the rain showers move through the airfield tomorrow night into Monday morning. Scattered rain showers move into Central Montana after the 10/00z time frame into Monday morning. VFR conditions prevail for KCTB and KHVR through the TAF period. Webb Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 624 PM MDT Sat Jun 8 2024/ Key Points: -Showers and thunderstorms Sunday afternoon across Southwestern Montana, with a few showers across the Plains Sunday night and Monday -Breezy Monday through Wednesday with a few locations seeing wind gusts over 45 mph -Dry and mild after Monday Through Monday While mostly clear skies continue across North Central and Southwestern Montana this afternoon, an approaching cold front is bringing a few clouds and isolated showers along the Hi-Line this afternoon, along with gusty winds across the plains. While any showers should remain confined to the areas north and east of Havre, the surface cold front will continue to push a bit further south through the rest of the day today, allowing a slightly cooler air mass to spread across the North Central Plains. Moisture will begin to work into Southwestern Montana late tonight and Sunday, which will help to kick off showers and a few thunderstorms across the Southwest Sunday afternoon and evening. Given that most of the storm bases will be 6-8000 feet above the surface with dry air below them, we will have to watch for some gusty outflow winds, which has prompted the Storm Prediction Center to highlight portions of Southwestern Montana with a marginal risk for severe wind gusts (5% chance within 25 miles of any point). The other thing that will need to be watched will be the chance for a few areas of heavy rain from these storms, but this threat should be isolated and given the recent dry spell soils should not have an issue absorbing the rain that falls with these storms. Storms will reach the plains on Monday as the southwest dries out, but these storms will not have much opportunity to cause any issues other than some lightning strikes. With that said, Monday will be a breezy day as deep mixing allows some 40-50 mph winds aloft to occasionally reach the surface. Tuesday through next Saturday Tuesday will be another gusty day across North Central and Southwestern Montana as a weak shortwave moves through the area. As this shortwave moves through, deep mixing of the boundary layer is expected once again, which will help bring winds of 30-50 mph to the surface once again during the day. Winds will begin to die down for Wednesday as this system moves east and as upper level ridging begins to build across the Western US. This ridge will then remain across the Western US through the end of the week, keeping us warm and dry. Ludwig && .PRELIMINARY POINT TEMPS/POPS... GTF 45 73 53 76 / 10 10 60 40 CTB 40 67 48 73 / 0 10 40 30 HLN 47 77 56 79 / 0 30 70 40 BZN 45 75 52 76 / 0 40 70 60 WYS 44 75 47 69 / 0 60 80 70 DLN 46 76 51 75 / 0 60 70 30 HVR 44 72 51 74 / 10 10 50 50 LWT 44 72 50 72 / 10 10 70 50 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls