251 FXUS65 KTFX 190618 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 1218 AM MDT Thu Oct 19 2017 .UPDATE... Quick update to include a High wind warning issued for the Northern Rocky Mtn Front, where gusts in excess of 75mph are being reported at several stations along the immediate east slopes. Strong winds aloft and favorable conditions for mountain wave induced winds will continue through tonight then abate Thursday morning. Hoenisch && .SYNOPSIS... Breezy west to southwest winds will increase late today and tonight across North Central Montana with windy and warmer conditions returning Thursday. Dry and windy conditions will raise fire concerns across Central Montana Thursday. The next front moves across the region with showers across Southwest Montana Friday, cooler temperatures, and windy conditions through Sunday. && .AVIATION... Updated 0500Z. West-Southwest flow aloft gradually backs to Southwesterly over the next 24 hrs with VFR conditions prevailing under scattered to broken high cloud-cover. Surface wind gusts increase to around 40kts in the KCTB vicinity by around 12z and somewhat higher along the Rocky Mtn front. Southwest winds increase across all areas Thursday afternoon with gusts to 30kts likely across most of the plains as well as some SW MT valleys, including the Madison valley and KEKS terminal. Hoenisch && .FIRE WEATHER... Breezy west winds this afternoon will continue into Thursday. Additionally, afternoon temperatures will warm into the mid/upper 70s with humidity falling into the low teens over the eastern portions of the region. Thus a Red Flag Warning is in effect for this region. More seasonable temperatures and slightly higher humidity move back into the region on Friday. However, it will remain windy most days from Friday through early next week. Brusda && .PREV DISCUSSION... /ISSUED 844 PM MDT Wed Oct 18 2017/ Moist and strong southwest flow aloft will persist across the region tonight. As such, the windy conditions will continue across North Central Montana but models are still indicating that even the strongest winds should remain below high wind criteria. Combination of downslope winds and cloud cover aloft will also prevent temperatures from falling too far. Finally, while orographic lift will bring widespread precipitation to northern portions of the Continental Divide, the strong downslope winds will prevent and showers from moving out over the plains. The current forecast package has a very good handle on all these variables and, at this time, it appears that no update will be required this evening. mpj .PREV DISCUSSION... /ISSUED 502 PM MDT Wed Oct 18 2017/ Tonight through Friday...Transient high pressure exits the region today with the next upper trough moving from the Gulf of AK toward the BC coast. Winds aloft will increase from the SW again later today and tonight. Gusty SW winds will persist across North-Central MT during the period with the strongest winds along the Rocky Mtn Front. Southwesterly flow aloft allows for temperatures to surge back to well above average Thursday as well. The upper level trough moves inland Thursday night and Friday with a surface front moving east across the forecast area by Friday afternoon. Precipitation will increase along areas near the Continental Divide Friday with showers also possible across Southwest Montana. Temperatures cool about 10 to 15 degrees for Friday and Saturday. Friday night through Wednesday...Look for spotty, light showers to persist following the passage of the cold front through the overnight hours Friday night and into Saturday. As colder air filters in from the north, temperatures will likely continue to drop, along with freezing-levels leading to the potential for accumulating snow for higher elevations of south-central and southwestern MT, especially along the Madison, Bridger and Gallatin Ranges. This system will quickly depart early Saturday leaving behind clearing skies with cool afternoon highs. However, by Saturday night clouds will begin to increase from the west as another quick moving system swings across just north of the MT/Canadian Border. Behind this system, models continue to confidently illustrate the development of a strong jet aloft, which will push eastward across the Northern Rockies into the early hours on Sunday. This will likely yield yet another high wind event across most of the CWA beginning Sunday morning, with the peak of the event being in the afternoon hours. Given forecast H7 wind speeds ranging between 55-75kts across the Plains, and even higher along the Rocky Mountain Front, strong winds aloft will have no trouble transferring to the surface via sufficient boundary layer mixing. Having said all of that, I have adjusted forecast wind speeds reflect a more realistic possibility of high winds following the jet aloft, timed with the best diurnal mixing in the afternoon hours. Looking at the synoptic pattern as we get into next week, long-range models have persistently been advertising the development of a re-enforcing ridge across the Southern Pacific coastline, which will reflect increasing heights across the majority of the western US. As strong ridging amplifies along the entire west coast, this will transition the upper-level flow more from the northwest and aid in the development of a dominant surface high across the northern Rockies. This will likely keep temperatures near, to slightly above normal while staying dry through the middle part of next week. KLG && .PRELIMINARY POINT TEMPS/POPS... GTF 48 58 36 54 / 0 40 10 10 CTB 42 55 33 51 / 0 10 10 10 HLN 43 55 35 55 / 0 40 20 10 BZN 43 58 30 51 / 0 70 40 10 WEY 33 48 22 38 / 0 70 50 20 DLN 42 51 28 47 / 0 60 30 10 HVR 43 62 35 56 / 0 20 10 10 LWT 45 59 33 51 / 0 40 20 10 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 11 AM this morning to 7 PM MDT this evening Central and Eastern Lewis and Clark National Forest Areas...Chouteau and Fergus Counties...Hill and Blaine Counties. High Wind Warning until 9 AM MDT this morning Northern Rocky Mountain Front. && $$ weather.gov/greatfalls