362 
FXUS65 KTFX 190033
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
630 PM MDT Mon Mar 18 2013

UPDATE TO AVIATION

.DISCUSSION...
Monday night through Wednesday...Afternoon convection beginning to
initiate off of some of the higher terrain. This activity should
continue ahead of the next shortwave trough that will move through
the area later tonight. Atmosphere should continue to increase in
moisture at the mid latitudes ahead of the next system. Shower
activity should remain relatively scattered with light
precipitation dominating the area....some bands of heavier
precipitation due have a chance of developing though under the
weak cape westerly winds. Will continue the winter weather
advisory for elevations above 5000 feet at this time due to the
radar returns over the area. Temperatures will climb through the
rest of the short term as a moist ridge moves into the area from
the pacific. Some showers will occur especially over the mountains
terrain due to the moisture aloft. Temperatures will continue to
rise above seasonal averages by Wednesday afternoon before the
next system moves into the area late Wednesday. Suk 

Wednesday Night through Sunday...A system approaching from the 
west will begin to affect Central Montana Wednesday night. Models 
remain in very good agreement with moisture entering Central 
Montana from the west Wednesday night with chances for 
precipitation spreading to Central and North Central Montana by 
overnight Wednesday into Thursday morning. Chances for 
precipitation and accumulating mountain snow look to remain 
over most of the area into Thursday afternoon as this system 
slowly moves over Montana. Showers Thursday night into Friday 
may remain along the Rocky Mountains and the Southwest 
Montana mountains. Precipitation over the plains of North Central 
Montana looks to still be showery in nature with the mountains 
likely getting the brunt of any precipitation. Models keep a 
generally unstable northwesterly flow and scattered chances of 
mountain showers over the region into Sunday. Scattered periods 
of gusty westerly winds will also be seen through the extended 
forecast period as surface flow remains generally west to 
northwest in nature. The strongest winds over the extended period 
look to be Thursday into Friday associated with the incoming 
system.  Temperatures have cooled quite a bit throughout the long 
term on this model run with highs generally in the low 40s over 
the plains with low 20s to low 30s in the mountains. Low 
temperatures will generally be in the 20s to 30s with 
teens and even single digits possible in colder Southwest Montana 
valleys. 


&&

.AVIATION...
UPDATED 0030Z.
The moist northwesterly flow aloft will keep at least mountain tops 
obscured in clouds/snow showers through around 12Z, with snow 
showers occasionally bringing MVFR conditions to the terminals of 
southwest Montana (KHLN KBZN). The initial round of scattered snow 
showers east of a KCTB-to-KGTF line, also with occasional MVFR 
conditions, will decrease from the northwest through 03Z. However, a 
disturbance will move south out of Canada between 03Z and 06Z with 
an associated cold front, which will shift winds more northerly over 
the north central Montana plains. This more upslope flow will cause 
more widespread light snow showers to develop over this area, mainly 
between 06Z and 12Z. Some showers may be heavier at times due to 
lingering weak instability, causing conditions to become low 
MVFR/high IFR at times. The disturbance will exit the area after 12Z 
and an upper level ridge of high pressure will move in from the 
west, for improving conditions with clearing skies across the area. 
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  17  43  28  55 /  30  10  10  20 
CTB  12  40  25  53 /  30  10  10  10 
HLN  24  46  30  54 /  40  10  10  20 
BZN  18  40  23  50 /  30  10  20  30 
WEY   4  36  13  41 /  30  10  30  60 
DLN  18  43  26  50 /  20  10  20  40 
HVR  16  39  22  50 /  20  10   0  20 
LWT  14  34  20  47 /  30  10  10  20 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 9 PM MDT this evening FOR 
ELEVATIONS ABOVE 5000 FEET FOR Northern Rocky Mountain Front...
Southern Rocky Mountain Front.

&&

$$

SHORT TERM...Suk
LONG TERM...WARANAUSKAS
AVIATION...COULSTON

weather.gov/greatfalls