Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 241745
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1040 AM MST Sat Jan 24 2015

AVIATION SECTION UPDATED

.UPDATE...

Strong NW flow aloft persists over the region today as a series of
shortwaves and upper level jet energy moves over the top of an an
upper level ridge centered just off the US West Coast and drops SE
across MT. Precipitation will largely be confined to the mountains
through this afternoon, though a few widely scattered showers
cannot be ruled out further east and current radar also shows a more
consistent area of showers also moving SE from SW SK into far NE
portions of the forecast area this morning. Have increased pops
some for the rest of this morning across Hill/Blaine Counties with
just some minor adjustments elsewhere. Snow levels have risen to
around 7500 feet across most of the forecast area as well and have
adjusted these and subsequent snow amounts in most mountain areas
through the rest of today. Remainder of the forecast is on track
with continued warming today along with somewhat lesser winds
through this afternoon before winds pick up again tonight.
Hoenisch

&&

.AVIATION...
UPDATED 1740Z.
VFR conditions expected through this evening. Weak upper-level trof
continues to work its way from north-to-south accompanied by patchy
areas of moisture over parts of southwest and central MT. Areas with
moisture (KHLN to KBZN and KHVR to KLWT) will continue to see
lowered ceilings (5000-8000 ft) and spotty -SHRA this aftn, with a
brief period of MVFR ceilings possible.  Meanwhile, area from KGTF
to KCTB will see mix of clear skies and scattered mid-level clouds.
Gusty winds will subside a a bit thru the aftn, but will still see
occasional gusts of 25-30 kts vcnty KCTB/KHVR through 22-23Z.
Waranauskas

&&

.PREV DISCUSSION...
/ISSUED 500 AM MST Sat Jan 24 2015/
Today through Monday...An upper ridge whose axis is centered off
the west coast will gradually shift east during the period and by
Monday the axis should extend from the central Rockies into
British Columbia. A weather disturbance aloft embedded in a moist
northwest flow aloft still looks like it could bring a few
showers to the eastern plains this morning and early afternoon.
Otherwise other weather disturbances aloft will bring continued snow
showers over the western and southwestern mountains with a slight
chance to chance of rain showers for the southwest valleys. Snow
levels will be rising to near 7000 feet by this afternoon and
should continue to rise tonight. This will keep precipitation as
generally rain for mountain passes. Temperatures in the lower
valleys should stay above freezing tonight so do not expect much
threat for freezing rain but will continue to monitor the
situation. As the upper ridge get closer precipitation will diminish
late tonight and Sunday morning with dry conditions expected by
the afternoon and these dry conditions will continue through
Monday.

High wind warning...Winds will diminish today before increasing
again later tonight and continuing into Sunday. At this time it
looks like winds will diminish Sunday evening but there is a
chance high winds could continue over the Rocky Mountain Front
through the night. At this time do not have enough confidence that
this will happen to extend the warning.

Near record high temperatures...The gradual warming trend is still
on track and by Monday some locations could be near record high
temperatures. The fly-in-the- ointment is that there could be
enough cloudiness to prevent temperatures from getting as warm as
forecast. Blank

Monday Night through Saturday...Not too much change from previous
models runs in the overall pattern shift through this period. An
upper level ridge of high pressure will keep the area dry and warm
through Tuesday, with temperatures on Tuesday reaching near record
highs in the 50s at lower elevations. A shortwave trough from off
the California coast will then move through the central Rockies
Tuesday night, which will drag the jet stream back south out of
Canada and into Montana on Wednesday. The resulting moist westerly
then northwesterly flow aloft will bring an increasing chance of
mainly mountain precipitation to the area for Wednesday through
Thursday. Temperatures will also cool down closer to normal through
this period. The upper level ridge will shift west of the area
during this time as well. The Hudson Bay low will also eject a
shortwave and move it south over central Canada and into the Great
Lakes region, which will shift the flow aloft more northerly over
Montana. This will usher a cold Canadian airmass into the area to
begin the weekend, as highs will mostly be in the teens for Friday
night and highs on Saturday will be in the 20s. The northerly
upslope flow will also bring a good chance of snow to much of the
area. Although there is significant uncertainty on how much snow
could fall during this time and how cold temperatures could get
(leading to possibly very cold wind chills), the situation will be
monitored over the next several days for possible winter weather
highlights.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  40  55  42 /  10  20   0   0
CTB  47  37  50  35 /  10  10  10   0
HLN  47  34  49  28 /  30  40   0   0
BZN  45  33  47  26 /  20  40   0   0
WEY  30  22  35  15 /  40  40  10   0
DLN  48  35  52  32 /  20  20   0   0
HVR  47  34  48  35 /  30  10   0   0
LWT  47  31  51  35 /  20  20   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 11 PM MST Sunday Eastern Glacier...
Northern Rocky Mountain Front...Southern Rocky Mountain Front...
Toole.

&&

$$

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