Area Forecast Discussion
Issued by NWS Great Falls, MT
Issued by NWS Great Falls, MT
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352 FXUS65 KTFX 161006 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 406 AM MDT Tue Jul 16 2024 .SYNOPSIS... High pressure will continue to bring hot and dry weather for the remainder of the week. Despite occasional shower and thunderstorm activity, most locations will see little in the way of rainfall relief. && .DISCUSSION... The latest satellite and radar analysis depicts an area of showers and thunderstorms moving southward out of the Canadian prairies into the Havre area this morning. Hi-res guidance has this activity fading off around or shortly after sunrise, but the responsible unsettled northwesterly flow aloft looks to persist through at least this evening with additional isolated showers and storms developing along the Rocky Mountain Front and the northern portion of North- central MT later this afternoon and evening. There also looks to be sufficient instability over the mountains south of I90 for isolated thunderstorms this afternoon and evening. PWATs are highest in the northern areas, running around 0.75 to 0.90 inches, where measurable rainfall will be most likely, but still mostly less than a tenth of an inch in most cases. Overall, the primary concern will be gusty winds and lightning strikes. High pressure will be the dominant weather feature for much if not all the week, offering continued very warm to hot temperatures, mostly dry conditions, and seasonable breeziness; however, despite the ridge amplification over the coming days, moisture and shortwaves will make their way up and over the high pressure system and bring an increase of showers and thunderstorms, especially Wednesday and Thursday. Sub-cloud layers look to be dry, so expecting a mix of wet and dry storms at best and the warm temperatures will ensure round the clock storm development. This period will need to be closely monitored for potential fire starts from lightning. As mentioned earlier, the pattern changes little heading into the weekend, more heat and mostly dry conditions despite isolated thunder activity. - RCG && .AVIATION... 16/06Z TAF Period Note: The NWS Great Falls Weather Forecast Office manages the following TAFs: KCTB, KHVR, KGTF, KLWT, KHLN, KBZN, KEKS and KWYS. VFR conditions are generally expected over the next 24 hours despite hazy skies mostly impacting slantwise visibility. A northwesterly flow aloft will maintain passing mostly mid-level clouds and perhaps an occasional isolated shower or storm for northern areas. Similar conditions are expected along the MT/ID border. Winds outside of showers/storms will be light easterly over the plains and light and variable in the southwest. Hot temperatures will continue to impact density altitude each afternoon for the remainder of the week. - RCG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .FIRE WEATHER... High pressure will continue to bring hot, dry, and seasonably breezy conditions for the remainder of the week. Minimum relative humidity values critically low at times with good to moderate overnight recoveries, lowest at mid- slope locations. Shower and thunderstorm activity will increase heading towards mid- week, but little to no rainfall in the presence of lightning and potential brief gusty winds may result in increased concerns for new fire starts. - RCG && .PRELIMINARY POINT TEMPS/POPS... GTF 91 60 95 63 / 10 10 10 10 CTB 88 56 92 60 / 20 20 10 20 HLN 94 60 97 63 / 0 0 10 10 BZN 91 55 94 57 / 0 0 10 10 WYS 83 42 84 44 / 20 20 30 10 DLN 88 52 91 55 / 0 0 20 10 HVR 89 60 94 63 / 20 20 0 10 LWT 85 55 89 60 / 20 20 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls