Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 272031
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
231 PM MDT Sun Jul 27 2014

.DISCUSSION...

This afternoon...Visible satellite imagery and lightning analysis
over Western U.S. shows clouds and lightning strikes associated
with monsoonal moisture working northward through the Great Basin
area. There should be a notable increase in mid- to high-level
cloud cover over Southwest Montana Monday morning as this moisture
moves overhead.

Monday and Tuesday...Residual mid-level monsoonal moisture...per
increased 500 mb RH values...will rotate around the northwest side
of the Western U.S. ridge from the California/Nevada area up into
Southwest/Central Montana. This added moisture will result in a
slight probability for isolated showers and thunderstorms.
Although precipitable water will be up around 0.75 inches, taking
the large surface dewpoint depressions into account, little rain
is expected from any storms that form. Therefore, the main
concerns will be gusty winds and lightning strikes. NAM shows
MUCAPE values peaking around 500+ J/kg over mountainous areas
while the GFS is lower. 0-6 km shear will generally be less than
30 kts. A few isolated showers or thunderstorms are possible
Tuesday afternoon/evening across mainly the higher elevations of
Southwest Montana. Uttech

Tuesday night through Saturday...A very summer like weather pattern
will reside over the region for the 2nd half of the work week. With
a strong upper level ridge of high pressure over the Northern
Rockies...expect afternoon temperatures to generally range from the
mid 80s to lower 90s at lower elevations across the region...with
overnight lows very seasonable...generally in the 50s. The chances
for precipitation still look to be quite low for much of the region
through the entire period. Some monsoonal moisture is expected to
move northward up into the region by midweek. However...the exact
timing and amount of moisture that is going to make it this far
north is still a bit uncertain. Thus isolated/low chance pops are
in place mainly for Southwest Montana and the Rocky Mountain Front
for later in the week. Additionally...the precipitable water does
not look overly high through Thursday...so any storms that do
develop before Friday will likely not be producing very significant
amounts of precipitation. Brusda

&&

.AVIATION...
UPDATED 1730Z.
High pressure will continue to provide dry and stable conditions.
Surface winds will be light. High clouds will increase over
southwest Montana after 00z. VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  89  57  88 /   0   0  20  10
CTB  52  87  53  88 /   0   0  20  10
HLN  58  92  60  91 /   0  20  20  10
BZN  52  89  53  88 /   0  20  20  10
WEY  42  79  44  78 /   0  20  20  20
DLN  53  86  54  84 /   0  20  20  10
HVR  54  92  55  93 /   0   0   0   0
LWT  54  88  55  88 /   0   0  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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