FXUS65 KTFX 071730 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1130 AM MDT Wed Aug 7 2024 ...Aviation Section Updated... .UPDATE... Northerly to northeasterly surface flow across the plains will combine with a weak embedded wave pivoting through cyclonic northwesterly flow aloft across the Northern Rockies today to result in showers and a few thunderstorms through the afternoon, primarily across Central and North-central Montana. Given overall instability is significantly lower for today, and that upper level support wanes as we get deeper into the afternoon, any thunderstorms that do form look to be more run-of-the-mill variety. Temperatures across the plains today will struggle to warm much at all, largely only reaching into the 60's, though a few locations across the eastern plains will sneak into the lower 70's. The coolest air will take a bit longer to spread into Central and Southwest Montana valleys, arriving on a briefly breezy northerly wind late afternoon and early evening. Those with outdoor plans should be prepared for this brief period of gusty winds out of the north, especially in north-south oriented valleys. The going forecast describes this situation well, so no significant updates were needed this morning. -AM && .SYNOPSIS... A cool northwest flow aloft with Pacific moisture will continue the numerous showers and scattered thunderstorms over most of North Central, Central, and Southwest Montana today. Weak high pressure building back into the area will start to decrease the coverage of showers and storms overnight into Thursday. Cooler than normal temperatures will persist through the weekend into next week, with chances for showers and thunderstorms each day. && .AVIATION... 07/18Z TAF Period Low CIGS, scattered showers, and isolated thunderstorms will continue to bring widespread MVFR/low-VFR conditions to the KCTB, KHVR, KGTF, KLWT, and KHLN terminals through 00-06z Thursday. Main threat from any isolated thunderstorms will be gusty and erratic winds. For the terminals of Southwest Montana (i.e. KBZN, KEKS, and KWYS) CIGS will largely remain VFR; however, and isolated showers and thunderstorms near KBZN and KEKS may briefly reduce CIGS to MVFR/low-VFR. Mountains will be predominately obscured over the next 24 hours. Precipitation coverage and intensity over Central and North Central Montana will gradually decrease through 00-06z Thursday, but an isolated shower may linger over/near the mountains through the morning hours on Thursday. - Moldan Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 530 AM MDT Wed Aug 7 2024/ Today through Thursday... A cool northwest flow aloft tapping into a moisture feed from the Pacific Ocean will keep numerous showers and scattered thunderstorms over much of North Central and Central Montana today. The focus for these showers will shift from North Central Montana this morning to more so over Central Montana this afternoon with the movement of the jet streak aloft and the spread of northeasterly upslope winds south over the plains. Precipitable water values will be a bit less than those with the storms yesterday and overnight, so widespread heavy rainfall amounts are unlikely. These clouds and showers will mostly keep temperatures over North Central and Central Montana from getting out of the 60s. Southwest Montana will be on the periphery of these showers and thunderstorms, which should allow temperatures there to warm more so into the 70s at lower elevations. These overall cooler temperatures will also hinder the development of strong instability during the afternoon, which will help keep most thunderstorms from becoming strong. A high pressure ridge is then forecast to start building back into Montana from the Great Basin overnight into Thursday, helping to lessen the Pacific moisture feed and generally decrease shower and thunderstorm activity, but temperatures should remain around 15 degrees below normal. Friday through next Wednesday... Ensemble model forecast clusters indicate that Montana will generally remain under a slightly anti-cyclonic westerly flow aloft, between a broad low pressure trough in Canada and a broad high pressure ridge over the Southwestern and South Central United States. As a result, the National Blend of Models is tending not to forecast any significant swings in the weather into next week. The overall trend is for a very gradual warm-up in temperatures, though they should remain below seasonal averages. The relatively unsettled pattern will also keep a chance for showers and thunderstorms over the forecast area each day, with the best chances occurring Saturday through Sunday; this is when forecast have at least moderate agreement in moving a shortwave trough through the area. -Coulston && .PRELIMINARY POINT TEMPS/POPS... GTF 64 49 70 48 / 80 20 20 10 CTB 62 46 67 44 / 80 40 20 10 HLN 75 52 75 51 / 70 20 20 10 BZN 79 48 74 46 / 40 30 10 10 WYS 76 40 73 41 / 20 10 10 30 DLN 80 46 73 46 / 20 10 10 10 HVR 70 49 73 46 / 60 20 10 0 LWT 62 44 66 41 / 90 30 20 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls