Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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307 FXUS65 KTFX 292055 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 255 PM MDT Wed May 29 2024 .SYNOPSIS... After a few showers and thunderstorms across Southwestern Montana this afternoon and evening, drier weather is expected to push into North Central and Southwestern Montana for the rest of the week. Expect highs to generally be seasonable across the area, with most lower elevations seeing highs gradually warm from near 60 on Thursday to the low to mid 70s for the weekend. && .DISCUSSION... Key Points: -A few thunderstorms are expected across Southwestern Montana this afternoon and early evening, some of which may bring gusty winds and a heavy downpour -Cooler and drier through the weekend Short Term (through Thursday)... A cold front continues to push through Southwestern Montana this afternoon, which has been the focal point for showers and even a few strong thunderstorms this afternoon that have brought some localized accumulating hail. Further north across the Plains, cooler and drier air have continued to work into the area, which has resulted in most areas seeing highs some 15-20 degrees cooler than they were yesterday. For the rest of the day today, expect showers and thunderstorms to continue across Southwestern Montana as they gradually shift off to the east, bringing briefly heavy rain, gusty winds, and small hail as they move eastward, while the plains will see skies gradually clear. Thursday will be a fairly quiet weather day, with just a few rain showers across the Hi Line along with some breezy winds as the cool and dry air continues to push in from the north and west. We will have to watch for some rises on streams and creeks across Southwestern Montana as todays rainfall makes its way downstream, but widespread flooding is not expected at this time. Ludwig Friday through next Wednesday... A weak high pressure ridge is forecast to move into the area on Friday, bringing at least one day of drier conditions, lighter winds, and a return to near normal temperatures. Model clusters indicate that a more progressive westerly flow pattern will develop for the weekend into the middle of next week, but there is some disagreement on when the disturbances will move through the area. As a result, the NBM keeps the area slightly warmer than normal with a chance for showers and thunderstorms each day, especially over the mountain areas of Central and Southwest Montana. -Coulston && .AVIATION... 29/18Z TAF Period Showers and scattered thunderstorms are on-going along and southeast of a KLWT, to KBZN, to KEKS line this morning, with additional showers and thunderstorms expected to develop and persist through approximately 00-06z Thursday at/near the KLWT, KBZN, KEKS, and KWYS terminals. Main threat from any thunderstorm, especially between 29/18z to 30/02z, will be strong and gusty winds. Otherwise, bursts of precipitation and/or low CIGS will lead to MVFR/low-VFR conditions south of a KGTF to KLWT line through 06z Thursday, with improvement to low-VFR/VFR conditions at the KGTF, KLWT, and KHLN terminals while MVFR/low-VFR conditions persist at the KBZN, KEKS, and KWYS terminals. Mountains will be obscured for much of the next 24 hours. - Moldan Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .HYDROLOGY... A disturbance will move through the area through this evening, with the focus for potentially heavy downpours from thunderstorms being over the area along and east of a line from Dillon to White Sulphur Springs to Lewistown. The main concern is that the rain will fall on warm mountain snowpack, causing rapid runoff. Most rivers should handle the extra water, as river levels are not exceptionally high, but some creeks and streams will run high and possibly out of their banks in some spots especially out of the Madison, Gallatin, Little Belt, and Big and Little Snowy mountain ranges. We are not anticipating widespread issues, but will monitor the situation closely for possible localized flooding. -Coulston && .PRELIMINARY POINT TEMPS/POPS... GTF 41 61 38 68 / 10 10 0 0 CTB 38 59 37 65 / 10 20 0 0 HLN 42 63 39 70 / 20 10 0 0 BZN 34 59 33 67 / 50 10 0 0 WYS 30 53 29 62 / 70 10 0 0 DLN 34 59 33 69 / 10 0 0 0 HVR 42 63 41 67 / 10 50 10 10 LWT 37 57 34 63 / 40 20 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls