Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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755 FXUS65 KTFX 131727 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1127 AM MDT Mon May 13 2024 ...Aviation Section Updated... .SYNOPSIS... One final warm day is expected today before a cold front brings cooler and potentially smokier conditions to the area for midweek and beyond. For today, expect a few showers and thunderstorms to pop up this afternoon, mostly across Southwestern Montana with just a few across the plains. A more widespread round of showers and thunderstorms is expected on Tuesday as a cold front pushes through the area. && .UPDATE... Visible satellite and radar imagery this morning shows a line of showers have developed from the northeast side down to the western side of Glacier National Park. These showers are likely (30%) to continue to develop and move eastward along the Rocky Mountain Front later this morning. Minor adjustment to probability of precipitation for the Rocky Mountain Front in the next 2 to 3 hours for rain shower development. Otherwise, the forecast remains on track for today with more showers and a few thunderstorms this afternoon and evening. Webb && .AVIATION... 13/18Z TAF Period Concerns this TAF period include increasing westerly to northwesterly winds this afternoon primarily across the plains, widely scattered showers and thunderstorms this afternoon into the overnight across most areas, and low VFR to MVFR ceilings across the plains tomorrow morning associated with additional showers. Overall, the scattered nature of showers and thunderstorms this afternoon as well as limited confidence with respect to timing of any thunderstorms at terminals has led to the exclusion of thunder mentions in TAFs at this time. Trends will be monitored this afternoon, with thunder mentions being introduced as confidence in the situation grows. Any showers or thunderstorms will carry a gusty outflow threat. -AM Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 515 AM MDT Mon May 13 2024/ -A few thunderstorms are expected today, with the best chances across Southwestern Montana -Wet weather expected Tuesday, with cooler temperatures for the rest of the week Short term (through Tuesday)... Upper level ridging responsible for the warm temperatures that we have had over the weekend will begin to shift to the east today, but not before allowing for one final day of warm temperatures in the 70s across North Central and Southwestern Montana. As this ridge moves east, a shortwave trough will begin to slide into the area from the west, which, combined with the warm temperatures, will help kick off a few showers and thunderstorms across the area, first across Southwestern Montana with a few showers popping up across the North Central plains. While these showers and storms should be fairly run of the mill type cells, though forecast model soundings across the plains do support the development of some disorganized outflows that could produce wind gusts to 40 mph or so. Most of these showers will dissipate after sunset, with just a few lingering through the overnight. A second, more widespread, round of showers and thunderstorms will move through the area on Tuesday as a cold front pushes into the area from Canada. Like tomorrow, most of these showers and storms should be fairly benign, with just a few areas of breezy winds as the storms pass. Behind these storms, noticeably cooler air will work into the area, keeping highs in the low to mid 60s. In addition, this cooler air will potentially be accompanied by a return of widespread smoke and haze from the wildfires that have begun to resurrect across Western Canada, but we will need to get a bit closer to get a better grasp on how much smoke will work into the area. Extended (Wednesday through next Monday)... Expect seasonable weather through the second half of the work week as upper level ridging over the eastern Pacific keeps our upper level flow westerly to northwesterly with a few weak disturbances moving through the area. For the most part, these disturbances will mostly just result in some periods of gusty winds Thursday and Friday as a few rounds of cooler air work their way into the area, but areas along and north of US 2 could see a few periods of light rainfall Thursday and Friday as these disturbances move through. Looking towards the weekend, there seems to be some consensus that a slightly more notable trough will work its way into the Northern Rockies, which could help spur some more widespread rain and mountain snow to at least parts of the area for the weekend. Ensembles diverge for the start of the new work week, though the overall pattern appears to remain unsettled as we head into next week. Ludwig && .PRELIMINARY POINT TEMPS/POPS... GTF 75 46 61 44 / 40 40 80 30 CTB 73 46 62 41 / 40 60 60 20 HLN 77 50 66 46 / 20 20 70 30 BZN 74 43 64 41 / 30 60 70 40 WYS 65 36 57 34 / 60 70 70 20 DLN 72 41 64 42 / 30 30 40 10 HVR 78 48 66 44 / 50 40 40 20 LWT 72 45 58 41 / 20 40 80 40 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls