091
FXUS65 KTFX 070511
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1111 PM MDT Sat Jul 6 2024

...Aviation Section Updated...

.SYNOPSIS...

Scattered showers and thunderstorms diminish in coverage this
evening and tonight. High pressure begins to build in on Sunday
for warmer and drier conditions. The warming trend significantly
increases next week with an extended period of very warm to hot
temperatures expected through at least the weekend.

&&

.Update...

Minimal updates this evening, mainly to linger low (15%) PoPs
through the night along the Continental Divide and then across
portions of Hill, Blaine, Chouteau, and Fergus Counties. Shower
and thunderstorm coverage has been decreasing throughout the early
evening hours across the CWA; however, another weak shortwave
within northwest flow aloft will slide southeast and over North
Central and Central Montana through the overnight hours tonight,
providing another opportunity for a few showers and storms into
Sunday morning. Additionally, inserted patchy fog mention for
Sunday morning given overall clear skies and light winds overnight
outside of the aforementioned shower activity. Latest HREF
probabilities support a 10-20% chance for patchy fog by Sunday
morning, particularly in and near the river valleys of North
Central through Southwest Montana. - Moldan

&&

.AVIATION...
07/06Z TAF Period

Scattered showers and isolated thunderstorms will continue to drop
southeastward across the region overnight. Looking ahead to Sunday,
the main concern at this time will be for widely scattered showers
and isolated thunderstorms, mainly over terrain late morning through
early evening. Otherwise, the only other concern will be for patchy
fog Sunday morning, but fog not forecast to impact terminals at this
time. -AM

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

&&

.PREV DISCUSSION...
/ISSUED 542 PM MDT Sat Jul 6 2024/

Remainder of this afternoon through Sunday night...Showers and
embedded thunderstorms from this morning have mostly moved east of
the CWA, but a more scattered variety of showers and storms will
continue to fire up over Central/North-central MT and southwestern
locations mostly north of I90 with the assistance of weak
perturbations within the northwesterly flow aloft and diurnal
heating. Although ML CAPE levels are approaching and exceeding 500
J/kg in spots, bulk shear mostly less than 20 kts will limit
storm strength and temporal longevity. Regardless, even general
thunderstorms such as these may produce gusty and erratic winds,
small hail, and brief downpours in addition to lightning. Most
showers and storms diminish and end this evening, but a few
lighter showers may linger into the overnight hours. - RCG

The building upper level ridge begins to nudge eastward Sunday,
though northwesterly flow will persist for one more day across the
region. There doesn`t look to be any embedded waves diving
southeastward through this flow however, so chances for showers
and thunderstorms look to decrease quite a bit. Given lingering
moisture and marginally cool temperatures aloft remaining in
place, showers and an isolated thunderstorm or two will remain in
the forecast on Sunday, particularly over over higher terrain.

Monday through next weekend...The aforementioned upper level
ridge will continue to slowly shift eastward, inland across the
western CONUS Monday into the middle of next week. A warming trend
will commence as a result, with temperatures pushing well into
the 90`s at lower elevations by Wednesday. The brute of the heat
looks to peak around Thursday, but an increasing share of longer
range ensemble members favor well above average temperatures
persisting into at least next weekend. - AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  82  55  88 /  10  10   0   0
CTB  49  83  52  88 /  20  10   0   0
HLN  53  87  58  92 /  20  10   0   0
BZN  45  80  51  87 /  20  20   0   0
WYS  36  75  38  80 /  20  20   0   0
DLN  45  79  49  86 /  10   0   0   0
HVR  50  82  55  90 /  30  20   0   0
LWT  47  74  50  83 /  20  20   0   0

&&

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

$$

http://www.weather.gov/greatfalls