Marine Weather and Tide Forecast for Neihart, MT

DISCUSSION
/Issued 440 AM MDT Sat May 17 2025/

- Meteorological Overview:

A few lingering light showers early this morning in association with a subtle disturbance in moist westerly flow will exit to the east with mainly dry and seasonable conditions through early this afternoon. Flow aloft turns more southerly later today through tonight as a negatively tilted upper level trough shifts inland.
Models continue to come into better agreement with the progression of this trough across the region as the initial wave moves into the region tonight before a secondary wave drops southeast from BC into the larger scale trough and closed low that remains centered south/southeast of the area later Sunday through Monday.

Showers and thunderstorms initially developing across SW MT early this evening should transition to an area of widespread rain that lifts north through central/north-central MT overnight as an embedded mid-level disturbance lifts north along a deformation axis between two previously mentioned waves. Focus for moderate to locally heavy precipitation with this initial round will be areas near the continental divide, particularly along the Rocky Mountain front Sunday morning as flow turns southeasterly.

A second round of widespread precipitation develops Sunday through Sunday night across eastern portions of central/north-central MT in association with a TROWAL extending north from the larger scale upper low moving by to the southeast. There is still some uncertainty with the exact location of this feature and the western extent of moderate to locally heavy precipitation and its duration with some potential for precipitation to linger through Monday night across eastern areas (through with decreasing precipitation intensity).

Snow levels initially 8000ft or higher will fall to around 6000 ft later tonight along the Continental Divide while remaining higher across areas to the east, where snow levels will lower to around 6000 ft Sunday night. While the larger scale trough and widespread precipitation move out of the area by Tuesday, additional disturbances moving through westerly flow will keep some chances for showers in the forecast through much of next week as temperatures moderate back to near seasonal averages.

- Forecast Confidence & Scenarios:

Probabilities for precipitation amounts in excess of 1.00" are as high as 50-60% along the immediate east slopes of the Rocky Mountain Front with the initial wave of moisture tonight through Sunday morning. Probabilities for an inch or more precipitation amounts with the second wave of moisture across eastern portions of north-central MT remain around 30-40%.

Passes along the continental divide will likely see some snow later tonight into Sunday morning with Big Hole and Chief Joseph passes in Beaverhead county having the highest risk (30-50%) of accumulations of 2" or more. Some snow with minor accumulation is also possible over passes in Jefferson and Lewis and Clark counties. Hoenisch

AVIATION
17/12Z TAF Period

Except for patchy early morning fog near some southwest MT terminals, mainly VFR conditions are expected through this afternoon. Showers and perhaps a few isolated thunderstorms develop late this afternoon across primarily southwest MT with an area of widespread rain developing and spreading north through central and north-central MT late tonight through Sunday morning.
MVFR conditions and mountain obscuration will become widespread overnight with IFR conditions possible in locally more intense precipitation. Light winds at most terminals will become easterly late this afternoon and evening across north-central MT. Hoenisch

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

PRELIMINARY POINT TEMPS/POPS
GTF 66 47 54 41 / 10 90 100 60 CTB 64 42 51 38 / 10 70 90 60 HLN 67 46 53 39 / 20 80 90 50 BZN 65 43 51 34 / 30 60 100 60 WYS 59 36 46 27 / 40 80 100 80 DLN 62 40 49 30 / 40 80 90 40 HVR 69 44 56 40 / 30 40 90 80 LWT 62 42 56 37 / 40 60 100 90

TFX WATCHES/WARNINGS/ADVISORIES
None.