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Area forecast discussion 
National Weather Service Great Falls Montana
1045 PM MDT Fri Mar 27 2015

Updated aviation section

Discussion...
no updates to going forecast at this time. High pressure aloft is
keeping the area mostly clear. A Chinook Arch of clouds is
lingering over the east slopes of The Rockies, but they are mostly
higher and thinner clouds. Showers are still on track to increase
over northwest Montana after midnight ahead of an approaching
shortwave trough. With still some uncertainty regarding how strong
winds will be over the plains behind the cold front, have elected
to keep the high wind highlights as is for now (warning for rocky
mtn front, watch for rest of north central/central montana). The
next shift can evaluate things further when the 00z GFS forecast
model arrives. Regardless, Saturday will be a fairly windy day
across most of the area, and the current highlights reflect this.
Coulston

&&

Aviation...
updated 0445z.
High pressure aloft continues to provide dry and stable conditions.
A Chinook Arch has developed in the Lee of The Rockies and will
persist overnight. A disturbance aloft and associated cold front
will move across the area after 15z with winds becoming gusty along
and behind the front. Showers will also develop behind the front.
VFR conditions prevail with increasing MVFR conditions due to low
ceilings and precipitation after 18z. Mountains will become obscured
at times.

&&

Previous discussion...
/issued 540 PM MDT Fri Mar 27 2015/
tonight through Sunday...the main weather feature during the
period continues to be an upper trough which is forecast to move
into western Montana Saturday morning and be in eastern Montana
by Saturday evening. Associated with the upper trough will be a
cold front which will move through the forecast area Saturday
morning. Precipitation will develop over the mountains of the
Rocky Mountain front by Saturday morning then continue into
Sunday evening. Snow levels near 9000 feet ahead of the front
will fall to as low as 5000 feet during the afternoon. Mountains
of the Rocky Mountain front will see several inches of snow with
amounts up to 6 inches possible. Scattered showers and gusty
westerly winds will occur over the plains and southwest valleys
Saturday afternoon as the trough moves into the area. Models are
indicating some better lift near the U.S. Route 2 area so have
gone with showers likely for this particular area. Expect showers
in the east to linger into the evening and have increased the
chances of precipitation from the previous forecast. Late
Saturday night into Sunday the forecast area will be under the
influence of a broad upper ridge over the northwest U.S. Expect
dry weather with the possible exception of the Rocky Mountain
front where there could be a few rain or snow showers. There will
be gusty westerly winds Sunday but they will not be as strong as
those of Saturday.

High winds...confidence is high for the Rocky Mountain front that
the high wind watch has been upgraded to a high warning.
Elsewhere confidence is marginal for a high wind event so will
continue to ride with the current high wind watch. Blank

Sunday night through Friday...broad high pressure will extend
across the Great Basin and northern rockies from Sunday night
through tues morning, making for quiet weather conditions with
high temperatures in the upper 60s to low 70s on Mon. The first
element of a trend back toward more seasonal conditions is
forecast to occur on tues as a quick-moving shortwave trof and
surface cold front cross The Divide by late morning. Forecast
models have been consistent for several runs in showing scattered
areas of light valley rain/mtn snow on tues aftn/eve, with
slightly better chances of precip over southwest Montana. Also, still
keeping an eye on tues for possible high wind highlights for the
central and hiline counties as projected winds aloft and surface
pressure gradient remain favorable for gusts of 50 mph or more.
The remainder of the week is basically an unsettled pattern with
persistent northwest flow aloft. A couple of additional
shortwaves will move through the flow on thurs and late Fri,
bringing periods of scattered rain/snow showers. The region's
current run of well- above normal temperatures will end with the
weather system on tues as daily highs will trend downward into
the low-mid 50s for Wed through Fri. Waranauskas

&&

Preliminary point temps/pops...
gtf 46 60 37 63 / 0 30 20 0
ctb 45 56 37 60 / 10 60 10 0
hln 43 60 36 63 / 10 20 10 0
bzn 37 63 29 63 / 0 30 10 0
wey 33 55 22 53 / 10 40 20 0
dln 42 60 31 61 / 0 30 0 10
hvr 41 63 33 67 / 0 60 30 0
lwt 47 62 35 63 / 0 50 30 0

&&

Tfx watches/warnings/advisories...
high wind watch from Saturday morning through Saturday evening
Blaine...Cascade...central and southern Lewis And Clark...
Chouteau...eastern Glacier...eastern Pondera...eastern Teton...
Fergus...hill...Judith Basin...Liberty...Meagher...Toole.

High Wind Warning from 3 am to 9 PM MDT Saturday northern Rocky
Mountain front...southern Rocky Mountain front.

&&

$$

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