FXUS65 KTFX 241033 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 433 AM MDT Wed Jul 24 2024 .SYNOPSIS... Hot and mostly dry conditions are expected today ahead of a cold front that will push through the area. Isolated to scattered dry thunderstorms are possible this afternoon across the region which may bring gusty winds and little to no precipitation. Elevated fire weather conditions will be a concern through Friday as the cold front continues its way across the state. Cooler temperatures will return by the weekend. && .DISCUSSION... Main Points for Today: -Today will be the hottest day across for central Montana with highs ranging from the upper 90s to mid 100s for many locations. -Fire weather will be a major concern this afternoon with hot temperatures, low relative humidity, gusty winds, and the threat for afternoon dry thunderstorms across much of the region. Impacts for Today: -Elevated risk of heat-related illnesses. -Dry thunderstorms may produce gusty/erratic winds and cloud to ground lightning leading to wildfires. Short Term (thru Friday)... Upper level ridging will bring another day of hot and mostly dry conditions to the region. Temperatures as high as 105 are possible for some locations in north-central Montana this afternoon with these same areas experiencing overnight lows in the upper 60s to low 70s. This combination of hot daytime temperatures and poor overnight recovery is what will create the most heat-related stress for those who do not have access to air conditioning. Thus heat-related illness will remain a concern both today and tomorrow. Another main concern for this afternoon will be dry thunderstorms. The first thunderstorms are expected to develop in far southwestern Montana in the 2 to 4 PM timeframe make their way to the northeast through the rest of the evening. Because these potential thunderstorms are expected to produce little to no rain they become a fire hazard with the potential for gusty and erratic winds as well as cloud to ground lightning. The main region of concern is southwest of a line from Augusta to White Sulphur Springs. In this region there is potential for more widespread development towards the afternoon and early evening. The main threat will start to taper off after 10 PM and any lingering thunderstorms will continue their trek to the northwest towards the hi-line. The dry thunderstorm threat will reappear both Thursday and Friday afternoon across much of central and southwestern Montana, although to a lesser extent than what is expected this afternoon. That being said, the continuing threat for gusty/erratic winds and cloud to ground lightning will make even isolated thunderstorms a concern for potential fires. It will also compound the threat of gusty winds on Thursday associated with the breakdown of the ridge. An elevated threat for fire weather will remain through at least Friday afternoon for either gusty winds or dry thunderstorm potential. On top of all this, hazy conditions will linger across the region through at least Thursday with more wildfire smoke being advected into the region from fires to the west. Poor air quality may be observed at times particularly across the hi-line. Otherwise, hot temperatures will continue Thursday with highs in the 90s to near 100 towards eastern Montana. By Friday, the cooler air will have a chance to filter through the region and the hottest temperatures are expected to be in the mid to upper 80s across central and southwestern Montana. Long Term... Looking beyond Friday, a more seasonable weather pattern is expected with a few chances of afternoon showers Saturday and Sunday, primarily for southwestern Montana. Heading into next week there has been some back and forth in the ensembles as to whether a ridge builds back over the intermountain west and how strong it might be. The latest model guidance is split on the ridge even making an appearance which means, for now, the best advice is to enjoy the cooler temperatures this weekend. -thor && .AVIATION... 24/06Z TAF Period Wildfire smoke and/or haze will continue to reduce slantwise visibility upon ascent/descent across all in Southwest through North Central Montana, but surface VIS and CIGs due to the smoke/haze will largely remain VFR over the next 24 hours. Primary concern to terminal operations in the 2406/2506 TAF period will be thunderstorms, which will begin to develop over the higher terrain of Central and Southwest Montana between 18-21z Wednesday. These thunderstorms will then move northeast and over the remainder of Southwest, Central, and portions of North Central Montana between mainly 21z Wednesday and 03z Thursday, although a few storms may linger even beyond 03z Thursday. Main threat from thunderstorms will be strong and erratic winds given the very hot and dry atmosphere in place over the Northern Rockies. Some mountain obscuration is possible near thunderstorms given cloud bases of 9-12kft. - Moldan Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .FIRE WEATHER... A Fire Weather Watch and a Red Flag Warning have been issued due to hot temperatures, low minimum relative humidity, gusty winds, and/or scattered dry lightning. Please, see the below WATCHES/WARNINGS/ADVISORIES section for temporal and spatial details. Elevated to critical fire weather conditions will remain through Thursday across central Montana. Outside of very hot temperatures and breezy conditions, the main concern for this afternoon will be isolated to scattered dry thunderstorms. The greatest threat will be southwest of a line from Augusta to White Sulphur Springs. Cities such as Helena, Boulder, Dillon, and Wisdom have the highest potential for seeing dry thunderstorms where little to no precipitation is expected but gusty and erratic winds as well as cloud to ground lightning will pose a significant hazard through the afternoon and evening hours. On Thursday, as the upper level ridge breaks down, winds will pick up out of the west across all of north-central and central Montana with gusts up to 45 mph possible for higher elevations and up to 35 mph for lower elevations. Temperatures will remain close to 100 degrees for many locations and another chance for dry thunderstorms, primarily affecting zones 116, 117, and 118, will be possible in the afternoon and evening hours. The next period of concern will be Friday afternoon. Minimum RH values are in the teens and wind gusts, particularly closer to the Rocky Mountain front, will be as high as 25 mph. Part of the uncertainty remaining is how the front will play out on Thursday. If the front is delayed the some of the critical fire weather potential will get pushed into Friday. At the very least, near- critical conditions are expected through Friday evening and any fire that is already active or gets started will likely be more difficult to control given how dry fuels are at this time of the year. -thor && .PRELIMINARY POINT TEMPS/POPS... GTF 102 66 95 55 / 20 30 20 20 CTB 98 63 85 48 / 20 30 0 10 HLN 101 65 97 57 / 30 40 20 20 BZN 100 61 97 54 / 20 20 30 30 WYS 88 52 83 48 / 20 20 50 40 DLN 94 60 92 54 / 30 30 30 10 HVR 105 68 99 55 / 0 30 20 20 LWT 99 64 95 52 / 20 20 40 50 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 9 PM MDT Thursday for Eastern Glacier/Toole/Central/Eastern Pondera/Liberty. Heat Advisory until 9 PM MDT Thursday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft-Eastern Toole and Liberty-Fergus County below 4500ft-Gates of the Mountains- Helena Valley-Hill County-Judith Basin County and Judith Gap- Northern Blaine County-Western and Central Chouteau County. Fire Weather Watch from Thursday afternoon through Thursday evening for Central and Eastern Lewis and Clark National Forest Areas-Chouteau and Fergus Counties-Helena and Townsend Ranger Districts of the Helena National Forest-Hill and Blaine Counties- Lewis and Clark National Forest Rocky Mountain District-Rocky Mountain Front-Lincoln Ranger District of the Helena National Forest. Red Flag Warning from noon today to 9 PM MDT this evening for Helena and Townsend Ranger Districts of the Helena National Forest-Lincoln Ranger District of the Helena National Forest. && $$ http://www.weather.gov/greatfalls