Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 212351
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
551 PM MDT Tue Oct 21 2014
Aviation Section Updated.
Tuesday through Thursday...Showers will continue to develop
and move through the area as a low pressure system tracks across
the area this afternoon and evening. Most of the precipitation is
expected to move off to the east overnight. Higher elevation
locations especially over the Rocky Mountain Front and Southwest
Montana can expect some light snow accumulations with this system
with the biggest impacts being to area passes with roadways
becoming snow covered and slippery overnight. A weak shortwave
ridge will build into the area behind the system passage and
temperatures should rebound back above seasonal averages by
Wednesday with warm and dry conditions also extending into
Thursday Night through Tuesday...Overall, seasonably mild weather
expected as a progressive pattern steers a series of Pacific low
pressure troughs through the area during the period. High pressure
ridge centered over the Rocky Mountain states at start of period
quickly gives way to Pacific low pressure trough during the weekend.
Models are in relatively close agreement with timing and strength of
system as it moves through with both ECMWF and GFS calling for
temperatures 10 to 15 degrees cooler and areas of rain or snow
showers, mainly over the west and southwest mountains. Downslope
winds will limit precipitation chances over the plains and valleys.
This low pressure trough starts working off to the east on Monday
with high pressure again rebuilding briefly before the next trough
begins pushing in Tuesday.
Surface cold front has progressed through central Montana as of 00Z.
Radar and surface observations depict a large area of stratiform
precipitation over central MT. Most terminals will maintain VFR
conditions in spite of light rain through around 0300 UTC. KGTF
continues to switch between VFR and MVFR with -RA. 00Z KGTF balloon
reports FZL at 072 MSL, so expect ICG from around FL 070 to 180 MSL
through 0300 UTC. Weather system heads into eastern MT, with
gradually clearing skies tonight. Nutter
.PRELIMINARY POINT TEMPS/POPS...
GTF 39 61 44 65 / 40 0 10 10
CTB 36 61 41 63 / 20 0 10 20
HLN 37 62 39 65 / 40 10 10 10
BZN 29 56 31 64 / 50 10 10 10
WEY 24 46 23 52 / 50 10 10 10
DLN 32 56 37 61 / 50 0 10 10
HVR 39 63 39 68 / 30 10 0 10
LWT 38 61 39 67 / 50 10 10 10