753
FXUS65 KTFX 030604
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1159 PM MDT Tue Jul 2 2024

Aviation Section Updated

.SYNOPSIS...
An active pattern will bring showers and thunderstorms to much of
the Northern Rockies through Thursday afternoon, with the highest
concentrations of showers and storms occurring on Wednesday.
These showers and storms will be relatively small in nature, with
only brief periods of rain are expected. None-the-less, burst of
moderate to at times heavy rain will be possible, especially
through this evening and then again on Wednesday.

&&

.UPDATE...
Updated forecast is out. Only change this evening was to adjust
pops towards current trends. Most of the showers have exited
Southwest MT, thus reduced Pops in that area. Otherwise scattered
showers/thunderstorms are continuing to move from northwest to
southeast through North Central MT. Thus continued Pops until at
least Midnight before starting to diminish them. Temperatures look
on track. Brusda

&&

.AVIATION...
03/06Z TAF Period

Unsettled weather conditions can be expected for many areas
along/north of I-90 from Butte to Bozeman through this period.
Expect the shower and thunderstorm activity to be most widespread
between 16z Wed and 01z Thu. Thunderstorms will be intermittent, but
around. The northwest flow aloft will continue into Thursday, with
scattered showers/thunderstorms continuing. Mountains/passes will be
obscured at times through the period. Brusda

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.PREV DISCUSSION...
/ISSUED 553 PM MDT Tue Jul 2 2024/

Rest of today through Wednesday...moist and unstable northwest flow
aloft will continue to support scattered to numerous showers and
thunderstorms across much of North Central, Central, and portions of
Southwest Montana through the period. The exception to this is
southwest of a line from West Yellowstone, to Dillon, to Chief
Joseph Pass where isolated showers and storms are generally only
expected. Areal coverage/footprint of individual showers and storms
will be relatively small throughout the timeframe; however,
Wednesday will have the highest concentration of showers and
thunderstorms, especially north of the US Hwy 12 corridor. While
thunderstorms throughout the period are not expected to be severe, a
few stronger storms can`t be ruled, especially through this evening
when instability will be the greatest. These stronger storms would
be capable of producing gusty winds of between 40-50 mph, especially
beneath collapsing cores, and small hail which could accumulate and
lead to road hazards. While PWATs are not overly impressive during
the period and the aforementioned footprints of the showers/storms
will be relative small, slow storm motions of between 15-25 mph
could lead to some ponding of water in poor drainage areas,
especially where training of showers/storms occurs. High
temperatures on Wednesday will be well below normal across the CWA,
with highs ranging from the mid-60s to low 70s. - Moldan

4th of July...The upper level ridge will try to move east of the CWA
today. However, the flow aloft will be out of the northwest during
the morning/afternoon hours. Thus there will be a small chance for a
light shower through late afternoon, the North Central MT having the
highest chances. By Thursday evening, enough dry air should work in
from the west, that most dry conditions are expected for Thursday
evening across the CWA.

Friday through Tuesday...A summer upper level ridge of high pressure
is forecast to build over the northern Rockies during this period.
The exact day in which the ridge builds seems to flop a bit from day
to day, but overall it looks like the ridge will start to build in
by next Mon/Tue. This will result in mostly dry conditions
developing over the weekend and continuing into early next week.
Additionally, afternoon temperatures will be on the rise, with most
areas averaging afternoon highs close to 10 degrees above normal by
next Mon/Tue. Overall, do expect a rather lengthy period of very
warm to hot temperatures to start to develop by early next week.
Some long range forecast prog afternoon temperatures near/above 100
degrees in many areas for several days by later next week. Even if
these progs are 10 degrees to warm, it is still looking rather
warm/mostly dry for most days next week. Thus, excessive heat and
fire weather statements might be needed by the later portions of
next week as fuels continue to dry out. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  67  48  74 /  40  80  40  20
CTB  51  65  46  73 /  50  80  40  10
HLN  50  74  51  79 /  10  60  40  10
BZN  46  71  44  73 /  20  50  40  10
WYS  37  65  33  66 /  40  50  40  10
DLN  41  69  39  72 /  10  20  10   0
HVR  53  70  51  75 /  60  80  40  30
LWT  46  65  46  68 /  40  80  40  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

http://www.weather.gov/greatfalls