Sunrise 6:16 AM   Sunset 8:34 PM Moonrise 12:00 AM   Moonset 7:00 AM

  Print   HELP   Reset   Save   Recall

FXUS65 KTFX 270541 AFDTFX

Area Forecast Discussion National Weather Service Great Falls MT 1140 PM MDT Fri Apr 26 2024

Updated Aviation Discussion

SYNOPSIS

Areas of rain and mountain snow will continue across the area through Saturday as a slow moving weather system moves through.
Warmer and drier air arrives for Sunday, but the active weather pattern will resume as we head into the start of the work week.

UPDATE

Main update to the overnight forecast period was to bring in scattered shower activity to the plains of North Central and Central Montana immediately, rather than more so after midnight.
Weak instability has combined with a weak frontal boundary over the area to create a wide band of scattered light rain showers there. Can see them to the north of the office here in Great Falls, but only some of the showers are reaching the ground.
Regardless, coverage is increasing on radar imagery, so have increased coverage accordingly, but am mainly expecting less than 0.10 inch from the heavier showers. Otherwise, the temperature and wind trend is on track, and these showers should gradually decrease over the eastern plains (including the Havre and Lewistown areas) from the east after midnight. -Coulston

AVIATION
1140 PM MDT Fri Apr 26 2024 (27/06Z TAF Period)

Moisture continues to be drawn north and northwestward into the region with scattered light showers across southwest MT as well as portions of central and north-central MT through Saturday morning.
Showers will become more numerous across western portions of north- central and central MT and most of southwest MT through the day on Saturday with precipitation slowly shifting east of the area Saturday night. VFR conditions prevail through Saturday morning at most terminals with some brief MVFR conditions with the passage of showers. MVFR conditions become more widespread with increasing precipitation coverage Saturday afternoon with some IFR conditions possible in more intense showers. Areas of mountain top obscuration will transition to more widespread terrain obscuration through the day Saturday as cloud bases lower. Surface winds become more easterly across the plains on Saturday with breezy east winds at KHVR and KLWT. Hoenisch

Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information.

PREV DISCUSSION
/ISSUED 615 PM MDT Fri Apr 26 2024/

Key Points:

-Cool and damp weather expected for Saturday with snow in the higher terrain -Unsettled weather continues through next week with periods of rain and mountain snow

Short term (through Sunday)... Current radar and satellite imagery continue to show precipitation moving in from the south as a broad upper level trough continues to work its way into the Northwestern CONUS. By and large, this precipitation has been largely beneficial, with no notable impacts occurring at this time with any snow melting on contact with any paved surfaces.
Expect precipitation to continue on and off through the rest of the day across Southwestern Montana, even as the area of precipitation continues to gradually make its way to the north.
As we head into the overnight hours tonight, expect snow levels to dip down to 6000 feet across the Southwest, which will allow for some nighttime accumulations across some of the mountain passes and some high elevation towns, such as West Yellowstone.

As we head into the day on Saturday, precipitation will coalesce along a line mostly along the continental divide to 50 miles eastward. Most of this will be light rain, though we could see some snow across the passes, such as Homestake, Marias, and McDonald Passes that would mainly stick to the grassy surfaces and may struggle to accumulate on the roadway thanks to the high late April sun angle. Further east across the southwest, we will still see a few showers and maybe a rumble of thunder as some showers develop over the higher terrain. Across the rest of the plains, expect mostly cloudy conditions through the day on Saturday until this band of precipitation moves east during the late evening and overnight hours. Sunday will see drier and slightly warmer air move into the area, resulting in a pleasant day to get outside across the area.

Extended (Monday through next Friday)... The first half of next week will be cool and unsettled as a series of upper level systems roll across the area. While the exact details remain uncertain at this time, overall expect multiple chances for rain and mainly mountain snowfall Monday through Wednesday, with even a nonzero chance for some snow reaching the plains at times, especially as we head towards midweek. Like the rain this weekend, this will generally be beneficial precipitation, though there could be some impacts if some snow were able to manage to stick, though at this point there isn’t nearly enough confidence to put much focus on the nature of any potential snow.

The second half of the week should bring warmer and drier weather as an upper level ridge builds into the area. We may still have a few leftover rain or snow showers as a few weak systems roll over the ridge, but these would likely be isolated and limited in duration. Ludwig

PRELIMINARY POINT TEMPS/POPS
GTF 38 57 39 62 / 40 70 60 10 CTB 36 55 35 58 / 20 60 30 0 HLN 44 56 39 61 / 60 80 60 20 BZN 41 58 37 59 / 40 70 70 60 WYS 33 50 32 49 / 70 90 80 70 DLN 39 48 35 56 / 70 90 50 20 HVR 39 66 42 66 / 30 20 30 20 LWT 38 58 38 58 / 30 20 30 50

TFX WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 6 PM MDT Saturday for Elkhorn and Boulder Mountains-Ruby Mountains and Southern Beaverhead Mountains.

Winter Storm Warning until 6 PM MDT Saturday for Gallatin and Madison County Mountains and Centennial Mountains-Northwest Beaverhead County.

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Great Falls, MT,