Scientific Forecaster Discussion
000 FXUS65 KTFX 231153 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 453 AM MST Tue Jan 23 2018 ...UPDATED AVIATION... .SYNOPSIS... Lingering mountain snow will diminish this morning...with mainly dry conditions then expected across the area. Temperatures will be near seasonal normals...with highs generally in the 30s. Some breezy winds are also possible today...especially across northern and central portions. Mainly dry conditions will again be found for Wednesday...with gustier winds and warmer temperatures also expected. A cold front will then return a chance for snow on Thursday...mainly across central and southern portions. && .DISCUSSION... Today through Thursday...Flat ridging will diminish any lingering mountain snow this morning...and leave us with mainly dry and seasonal conditions for today. Clearing skies could also cool off some southwestern valley locations just enough to see patchy freezing fog this morning. Impacts will be isolated and brief. Afternoon breezes may then pick up for the usual areas of northern and central portions today. Ridging stays in place for tonight...continuing the mainly dry conditions. Lingering breezes will also keep temperatures near seasonal to slightly above normal readings. The mentioned ridge then pushes to our east on Wednesday bringing us southwest flow ahead of the next potential weather maker. Moisture in this flow could bring some mountain snow...especially along the Rocky Mountain Front. A strong gradient also begins to develop ahead of an approaching cold front...bringing the potential for gustier winds on Wednesday. Gusts look to be below High Wind criteria at this point...although will be worth watching in the coming days. Temperatures will also warm up in the down sloping flow...with some highs returning into the 40s for the northern and central portions...and mid to upper 30s across the southwest. Thursday then sees the passage of this weak pacific cold front. Right now the best chances for snow will come across the Rocky Mountain Front and southwestern portions...with some scattered activity across central portions. Snow accumulations at this point look to be light...with perhaps 1 to 4 inches possible across the heavier hit areas of sw MT. Temperatures will be slightly cooler on Thursday...although still near to above normal. Anglin Thursday Night through Tuesday...Cold front exits the region Thursday night...ending the initial round of snow. Flat ridging then leaves us in a zonal moist westerly flow for Friday. This could bring scattered areas of light snow showers and lingering mountain snow. A pattern of brief ridging followed by moist westerly flow then looks to be the story of the weekend. A brief ridge moves through Saturday morning before moist westerly flow moves through the rest of Saturday. This combined with a weak warm front boundary could bring more scattered snow showers and mountain snow on Saturday...with a similar pattern also expected for Sunday. A mainly dry and breezy pattern looks to be possible for Monday. Models are then indicating a larger wave and stronger cold front may then push across the region sometime early next week. The exact timing is still in disagreement...with some models indicating impacts could be seen as early as Tuesday. If that is the case...this quick hitting system could bring chances for widespread snow and colder conditions. Temperatures Friday through Saturday look to be near seasonal normals...with a slight warm up on Sunday and Monday. After that models diverge...although it does appear perhaps a cool down is in store if the mentioned disturbance moves through. Anglin && .AVIATION... Updated 1200Z. Overall VFR conditions expected through the forecast period. Patchy fog is possible across the southwestern valleys this morning...although impacts look to be isolated and confidence was to low to include in TAFs at this point. Lingering mid level clouds could also briefly bring MVFR ceilings this morning to southwestern sites. The rest of the day will see VFR conditions...partly cloudy skies...and some breezy winds at times to most sites. Mainly dry conditions are also expected to all sites today...with only a few lingering mountain snow showers possible this morning. Anglin && .PRELIMINARY POINT TEMPS/POPS... GTF 38 29 46 32 / 10 10 0 0 CTB 35 24 41 26 / 10 10 10 10 HLN 36 16 36 20 / 10 10 0 10 BZN 32 15 37 20 / 10 10 0 10 WEY 23 10 29 15 / 20 30 10 10 DLN 31 18 38 24 / 10 10 0 10 HVR 31 17 35 21 / 0 10 10 10 LWT 34 25 42 26 / 10 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None.