Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 021049
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
448 AM MDT Tue Jun 2 2020

...Updated Aviation Discussion...

.SYNOPSIS...

Dry conditions with seasonal temperatures are forecast into
Thursday. Expect widespread gusty winds through Wednesday. Fire
concerns increase where grass is dry. Friday will be the warmest
day of this week, with highs reaching into the mid 80s. Expect
periods of thunderstorm activity. Beginning Sunday, temperatures
trend cooler through mid next week.

&&

.DISCUSSION...

Tuesday through Thursday...With a low pressure system located off
of the west coast of southern California, a trough moving
eastward out of the region, and another upper level low located
over The Gulf of Alaska, the upper level pattern has become zonal,
setting up a strong westerly cross barrier flow. Mild
temperatures and dry conditions will continue through Thursday,
with strong and gusty winds prevailing across the region due to a
tight height gradient aloft.


Friday and Saturday...Early Friday morning, ridging begins to
develop over The Treasure State, and highs will reach into the mid
80s in some areas; however, the low previously located in The
Gulf of Alaska moves southeastward along the Canadian west coast,
and the pattern begins to become more meridional. Friday
afternoon, Montana begins to feel the impacts of the approach of
this system. Instability and moisture, along with the Polar Front
Jet moving overhead, will favor rainfall and possible thunderstorm
activity Friday and Saturday afternoon and evening.

Sunday through Next Tuesday...As this trough moves slowly through
the western United States, temperatures cool, and periods of
rainfall can be expected. Recent warm temperatures have been
favorable for the melting of mountain snowpack. Adding rainfall to
the rivers and creeks next week, may cause some areas of flooding.
We will monitor and update the forecast as necessary.

&&

.AVIATION...
Updated 448 AM MDT Mon Jun 2 2020 (02/12Z TAF Period)

VFR conditions prevail but with spotty mountain obscurations
continuing over parts of southwest MT this morning, with mostly
clear skies everywhere else. A few showers and perhaps a
thunderstorm may develop between KBZN and KWYS and move east during
the afternoon and evening hours Tuesday, with mtn obscurations re-
developing. A cold frontal passage after between 06z/Wed and 12z/Wed
will cause winds to increase and become gusty.

NOTE: Amendments not scheduled for Ennis (KEKS) due to ongoing
runway closure.

&&

.HYDROLOGY...

The Gallatin river remains near minor flood stage, levels have
decreased some; however, an upward trend has begun, again. This
river is expected to level off and trend lower. The flood
advisory for the Gallatin river continues for now with further
monitoring. A few other rivers are running strong and will
continue to be monitored. These include the Sun River near Simms,
and the Big Hole river near Melrose.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  76  53  75  47 /   0   0   0   0
CTB  73  49  70  44 /   0   0   0   0
HLN  78  54  77  50 /   0   0   0  10
BZN  77  50  79  49 /  10   0  10  10
WYS  71  42  72  41 /  20  20  20  10
DLN  76  51  78  48 /  10   0  10   0
HVR  78  53  76  46 /   0   0   0   0
LWT  71  50  72  46 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
A Flood Advisory is in effect for the Gallatin River until Tuesday
afternoon.

&&

$$

http://www.weather.gov/greatfalls


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