247 FXUS65 KTFX 261142 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 542 AM MDT Mon Jun 26 2017 ...Update to Aviation... .SYNOPSIS... Upper level high pressure ridge over the region will bring hot and dry conditions to Montana today. A surface cold front sweeps across the state overnight for showers and thunderstorms with cooler temperatures expected Tuesday. && .DISCUSSION... Today through Wednesday...Upper level ridge moves over the region for very warm to hot conditions today. A surface low pressure system will develop along the east slopes of the Rockies in southern Alberta for increasing southeast flow at the surface. Models are in agreement that this low will progress eastward overnight with a surface cold front sweeping through Montana early Tuesday. This timing is about 12 to 18 hours slower than models were indicating over the last few days. As a result, I have lowered PoPs somewhat for today and tonight and increased them a bit for Tuesday. Behind the cold front, breezy west to northwesterly winds will develop across North Central Montana for Tuesday night and Wednesday. Despite impressive CAPE values expected across the forecast area today and Tuesday, it appears that the risk for widespread severe weather is relatively low. However, I still can not rule out one or two short lived storms that could produce locally strong outflow winds and marginally large hail, especially this evening. mpj Wednesday Night through Sunday...An unsettled, northerly flow aloft develops Wednesday night and Thursday associated with a closed upper level low drifting through AB/SK. A cold front trailing behind this system will lower temperatures into the low- to mid-70s on Thursday. This pattern brings chances for scattered showers and thunderstorms, although model guidance continues to differ on the timing and spatial extent of this activity. The latest forecast guidance has slowed the departure of the upper low, with chances for isolated light rain showers continuing Thursday night into Friday. Model consensus suggests weak ridging through the weekend, providing generally fair weather with temperatures near 80F and isolated showers or thunderstorms possible. PN && .AVIATION... Updated 1142Z. Variable high clouds will move over the forecast this morning with increasing mid and high level clouds after 18Z. Surface winds will also increase during the afternoon and there will be an increasing chance for showers or thunderstorms over the Rocky Mountains by 21z. Surface front sweeps through the region overnight with scattered showers and thunderstorms and increasing west winds behind the front. VFR conditions will prevail but short-lived MVFR conditons are possible in precipitation with mountains becoming increasingly obscured overnight. mpj && .FIRE WEATHER... A Red Flag Warning has been issue as confidence increases that there will be critical fire weather conditions Monday afternoon into evening in our far northeastern areas, primarily Blaine County. Gusty southeast winds ahead of a surface low pressure system will combine with minimum RH values in the teens and increasingly dry fuels in eastern portions of Fire Weather Zone 113. CC/MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 92 60 77 50 / 10 40 50 20 CTB 90 58 76 48 / 10 40 40 10 HLN 93 60 78 52 / 30 50 60 10 BZN 91 54 76 47 / 10 20 60 30 WEY 81 43 68 38 / 10 30 60 30 DLN 89 54 73 47 / 10 40 50 20 HVR 95 62 81 52 / 0 20 40 20 LWT 87 58 75 48 / 0 30 50 30 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon today to 8 PM MDT this evening Hill and Blaine Counties. && $$ weather.gov/greatfalls