867
FXUS65 KTFX 041003
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
403 AM MDT Tue Jun 4 2024

.SYNOPSIS...

Very windy conditions continue through tonight across the area with
strong winds becoming more widespread across north-central and
central Montana this afternoon and evening. Winds gradually decrease
on Wednesday with warmer and drier conditions following through the
rest of the week.

&&

.DISCUSSION...

A compact mid level low and surface low pressure located in SW
Saskatchewan this morning will lift slowly northeast today while an
unusually strong upper level jet is streaming across the
Northern Rockies with highest speeds still offshore (130-140kt)
streaming east roughly along the US/Canadian border tonight. All of
this translates to a continuation of very windy conditions for the
area through the next 24 hrs with a peak in wind intensity this
morning, decreasing somewhat around mid-day before intensifying again
late this afternoon through this evening.

Except for some showers circulating around the mid level low
this morning across Hill and Blaine counties and showers at times
near the continental divide through tonight, most of the area will
see dry conditions and temperatures slightly cooler than average with
wind being the primary weather impact through tonight. Strong
wind gusts (in excess of 55 mph) early this morning are primarily
confined to mountain wave enhanced areas along the Rocky Mtn
Front and N/E slopes of the north-central MT mountain ranges,
however 35-45 mph gusts are common outside of this area across
central/north-central MT and across the higher terrain of
southwest MT. General wind flow across the area decreases slightly
later this morning into early this afternoon before increasing
significantly late this afternoon through this evening. Within the
overall larger wind maximum, an area of 70-80kt 700MB wind speeds
is supported by most models across central MT this evening. Wind
speeds of this magnitude are highly unusual for early June and at
least locally above the 99th climatological percentile per
ECMWF/NAEFS ensembles. No changes were made to the High Wind
Warning overnight, which expands to cover remaining portions of
north-central MT later this morning and continues through tonight.
While strong wind gusts will likely have the greatest coverage
across the area late this afternoon and evening, the highest gusts
may continue through the overnight period in mountain wave
enhanced areas downwind (east/northeast) of the Southern Rocky
Mountain Front and Little Belts.

Winds decrease on Wednesday with a quieter and warmer period of
weather developing as upper level ridging gradually amplifies across
the Western US into the upcoming weekend. Temperatures warm above
seasonal averages beginning Thursday and are likely to remain
above average well into next week with upper level ridging over
the Western US supported by most longer range model ensembles.
Moisture circulating around the ridge gradually creeps into the
area from the SW as early as Friday afternoon and moreso through
the weekend for some isolated diurnal shower/thunderstorm
possibilities, initially across southwest MT. There is some
indication of a more substantial push of moisture and shortwave
moving over the ridge in the Sunday/Monday timeframe for more
widespread shower/thunderstorm potential. Hoenisch

&&

.AVIATION...

04/06Z TAF Period

VFR conditions will prevail through the TAF period with cloud decks
at multiple layers across all sites. Strong westerly flow aloft will
continue through the rest of Tuesday into Wednesday creating a
hazard for strong mountain wave turbulence. Conditions will be
generally dry through the period with some light showers possible
near the Rocky Mountain Front (but not expected to impact KCTB).

At airport level, expect maximum wind gusts of:
- KCTB: up to 60 kts
- KGTF, KHVR, KLWT: up to 52 kts
- KHLN: up to 40 kts
- KBZN, KEKS, KWYS: up to 30 kts

Winds will start to ease up after 04/03Z and continue diminishing
through the overnight hours into Wednesday morning. -thor

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  68  47  71  43 /  10  10   0   0
CTB  61  43  67  40 /   0   0   0   0
HLN  70  50  76  48 /  10  10   0   0
BZN  69  49  76  44 /  10  10   0   0
WYS  61  43  73  40 /  10  10   0   0
DLN  68  48  77  45 /  10  10   0   0
HVR  72  48  71  43 /   0   0   0   0
LWT  68  46  67  42 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until noon MDT Wednesday for Bears Paw
Mountains and Southern Blaine-Big Belt, Bridger and Castle
Mountains-Cascade County below 5000ft-East Glacier Park Region-
Eastern Glacier, Western Toole, and Central Pondera-Eastern
Toole and Liberty-Fergus County below 4500ft-Judith Basin County
and Judith Gap-Little Belt and Highwood Mountains-Meagher County
Valleys-Northern High Plains-Snowy and Judith Mountains-Southern
High Plains-Southern Rocky Mountain Front-Upper Blackfoot and
MacDonald Pass.

High Wind Warning from 9 AM this morning to noon MDT Wednesday
for Eastern Pondera and Eastern Teton-Hill County-Northern
Blaine County-Western and Central Chouteau County.

&&

$$

http://www.weather.gov/greatfalls