033 FXUS65 KTFX 040512 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1110 PM MDT Fri May 3 2019 .SYNOPSIS... Temperatures trend cooler through the weekend across North-central Montana as a cold front moves in from Canada. Cool and raw conditions will prevail for this area with periods of rain and higher elevation snow. Rain and snow chances increase further Sunday into Monday. Generally fair weather prevails over Southwest Montana through the weekend. && .UPDATE... Showers forecast for the Hi-Line and my eastern zones have so far been pretty weak on radar and I have received no reports of observed precipitation. As such, have updated to lower evening PoPs to slight chance. However, most short term model updates are indicating that shower activity should increase after midnight so have kept chance PoPs in for the overnight hours and into Saturday morning. Forecast continues to look favorable for a Canadian cold front to slip southward with precipitation expected to increase across North-Central Montana Saturday afternoon and evening. For this time period have actually increased coverage of likely PoPs and bumped up QPF values. Remainder of the forecast does not appear to need any changes. At this time it appears that overnight lows, winds and Saturday highs are all in the right ballpark so have left these forecast elements as-is. mpj && .AVIATION... Updated 1110 PM MDT Fri May 3 2019 (06Z TAFs) Surface cold front moved through KCTB and KHVR terminals earlier this evening on track to shift winds to the N/NE at KGTF by around 08-09z. So far not much in the way of lower cigs or precip immediately behind the front, but observations upstream in AB support some MVFR/IFR potential in low clouds/cigs to develop over the northern tier of the forecast area later tonight through early Saturday. VFR conditions prevail over SW MT. Hoenisch && .PREV DISCUSSION... /ISSUED 530 PM MDT Fri May 3 2019/ A surface cold front is slowly working its way into North-central Montana this evening. Daytime heating and weak instability in the warmer air ahead of the front has produced low level clouds and scattered showers, mainly over eastern portions of North-central Montana. Low clouds will increase in coverage overnight as the front settles into the area. Forecast guidance continues to suggest the front will stall, and not advance further into central Montana. Drizzle or light rain becomes possible north of the front on Saturday. Meanwhile, fair and mild conditions prevail over Southwest Montana. A mid-level warm front advancing over the cooler air, ahead of an advancing shortwave trough will produce a more widespread area of light to moderate rainfall across North-central Montana. As this wave passes by, the front will drift a bit further south and deepens the colder air. Rain can begin to change over to snow Sunday night into early Monday, most likely over the Northern Rockies and across the HiLine. A few inches of snow accumulation appear possible above 4500 feet along the Rocky Mountain Front. This area will need to be monitored for possible winter weather headlines on subsequent forecast shifts. Weak instability may permit isolated thunderstorm development during the afternoon and early evening hours of Sunday and Monday. Tuesday through next Friday...The longwave trough aloft and embedded shortwave disturbances should continue to affect our area through Thursday as the longwave drifts eastward. By Friday, high pressure ridging aloft may begin overspreading our CWA from the west. Isolated rain and/or snow showers remain possible, especially over/near higher terrain and during the late morning through early evening hours of each day. Isolated thunderstorms may occur Tuesday and Friday afternoon, respectively, when limited daytime heating may yield weak, yet sufficient instability. Despite a gradual warming trend, temperatures remain below-normal. && .PRELIMINARY POINT TEMPS/POPS... GTF 35 59 37 52 / 10 10 40 40 CTB 32 55 32 45 / 10 60 70 60 HLN 36 65 39 63 / 0 0 10 20 BZN 33 64 36 65 / 0 10 0 20 WEY 24 56 27 59 / 0 10 0 20 DLN 34 64 36 66 / 0 0 0 10 HVR 34 53 33 47 / 40 30 60 50 LWT 33 56 34 49 / 10 30 60 50 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls