Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 282031
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
231 PM MDT Sat Mar 28 2015
Tonight through Monday...An upper level low pressure trof will move
east of the region this evening and winds will decrease through the
evening. The high wind warning is currently scheduled to expire at 9
pm this evening and will not make any changes to the timing. High
pressure aloft will build through Monday and the air mass will warm
and dry. Temperatures will trend upwards as the air mass warms and
temperatures by Monday could be 20 degrees or more above seasonal
Monday Night through Saturday...Period begins with dry conditions
through midday Tues as high pressure ridge gradually tracks eastward
across the state. Forecast models still indicating arrival of a
Pacific shortwave trof, surface cold front and accompanying valley
rain/mtn snow showers on Tues, though with a few changes. Most
notable is a 4-6 hr delay in the system and precipitation crossing
the Divide, now projected for mid-late aftn into Tues eve. Also,
overall precip coverage and amounts have been reduced, especially
over parts of the central and Hiline counties. Lastly, winds aloft
and the surface pressure gradient are a bit weaker than previous
model solutions, suggesting that much of our region will still have
gusty winds on Tues aftn/eve with cold frontal passage, but the
probability of needing high wind highlights has decreased.
Latter half of the week still looks cooler and unsettled as Northern
Rockies remain under western boundary of a longwave trof centered
over eastern portions of the US and Canada. Another upper-level
shortwave is expected to swing through MT from Thurs aftn through
Fri morning with another round of light rain/snow. Models diverge
a bit on Sat with the European/Canadian models showing a marked
return of high pressure ridging and warm, dry conditions.
Meanwhile, the American GFS model depicts only slight transient
ridging, with a weak system moving along the US/Can border
generating showers along the Rocky Mtn Front and Hiline areas.
Current forecast grids compromise between these solutions, leaning
slightly more toward the drier Euro/Can solution.
VFR conditions will prevail for the next 24 hours. Main concern
continues to be the strong winds near the surface and clear air
turbulence aloft as a cold front move across the area today. Some
shower activity near mountains may create some obscurations and
sites located away from the Rock Mountain Front could see a brief
reduction in flight categories due to showers. By 06z most locations
should be under lighter winds as the system quickly moves off to the
east. After 12Z on the 29th, winds should pick up again along the
Rocky Mountain Front. Suk/db
.PRELIMINARY POINT TEMPS/POPS...
GTF 36 62 40 69 / 20 10 10 0
CTB 35 59 41 65 / 20 10 0 0
HLN 36 63 39 69 / 10 10 10 0
BZN 27 63 32 69 / 10 0 0 0
WEY 20 52 25 57 / 10 0 0 0
DLN 30 61 34 68 / 0 0 0 0
HVR 33 66 36 69 / 50 0 0 0
LWT 36 62 39 68 / 40 0 10 0
HIGH WIND WARNING until 9 PM MDT this evening Beaverhead...
Blaine...Broadwater...Cascade...Central and Southern Lewis and
Clark...Chouteau...Eastern Glacier...Eastern Pondera...Eastern
Liberty...Madison...Meagher...Northern Rocky Mountain Front...
Southern Rocky Mountain Front...Toole.