Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/18/20
Area Forecast Discussion
National Weather Service Great Falls MT
802 PM MDT Wed Jun 17 2020
The surface low that has been impacting the region continues to
slowly rotate through the area, causing widespread precipitation.
Expect snow at elevations above 7000 feet, and rain at lower
elevations. The forecast is working as intended; therefore, no
changes will be made, at this time.
Scattered to widespread showers are expected over the area tonight
through Thursday. Some snow is possible over Southwest Montana
but will likely remain above pass level. Temperatures will also
remain 10 to 15 degrees below normal during this time. High
pressure ridging will then bring warmer and drier weather starting
Friday and continuing into early next week, with some scattered
showers possible at times.
Tonight through Friday...Large upper level trough will begin to
wrap up into a large upper low overnight tonight and gradually
progress eastward. The result is still widespread rain showers,
although with somewhat diminished coverage than earlier today.
Snow levels tonight will generally be above 7000 feet and bring
limited impacts to the area. Thus have continued with no winter
weather highlights for the night. Overnight lows will again be
below normal, and generally in the 30s and 40s. The mentioned
upper low then spins around in Canada leaving MT in northwest flow
for Thursday. The result will be continued cool temperatures with
scattered rain showers and perhaps an isolated thunderstorm. Due
to scattered activity of showers QPF values are a little tricky to
pinpoint, although and additional 0.25 to 0.50 inch of rain is
possible for some reasons. Showers then become more isolated
Thursday night while temperatures again remain below normal. Some
areas of fog are also possible for Thursday night into Friday
morning. As the trough exits the area on Friday, the northwest
flow will keep a chance of showers mainly during the afternoon
hours. Daytime heating will bring weak instability during the
afternoon, causing a chance for a few thunderstorms each day.
However, any storms should remain weak. Temperatures will remain
10 to 15 degrees below normal today through Thursday, with a
warming trend starting on Friday. Anglin
Saturday through next Wednesday...Forecast models continue to
indicate that weak high pressure ridging will gradually build over
the western United States during this period. This will continue
the drying and warming trend, allowing temperatures to warm to
between 5 and 10 degrees above normal. However, weak energy in the
resulting westerly flow aloft will keep at least a slight chance
of mainly afternoon and evening showers and thunderstorms.
Updated 639 PM MDT Wed Jun 17 2020 (18/00Z TAF Period)
During the first hour or two of this TAF period, isolated
thunderstorms build and collapse as they move across parts of
central Montana. These storms are not expected to impact airfields.
Most TAFs include periods of MVFR conditions, with the KWYS TAF
including IFR conditions, and possible IFR conditions at KLWT. Snow
is forecast across mountain peaks. Expect aircraft icing and
mountain obscuration. The strongest winds are forecast for KCTB with
gusts to as high as 27KT from the NNW. Expect the associated
turbulence. Thunderstorm activity is forecast for southwest Montana,
Thursday afternoon and evening. For detailed aviation hazard
information, please see:
NOTE: Amendments not scheduled for Ennis (KEKS) due to
ongoing runway closure.
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 62 44 70 / 70 60 40 30
CTB 45 62 44 69 / 70 40 50 40
HLN 47 62 45 72 / 80 70 30 20
BZN 42 61 40 72 / 80 50 20 10
WYS 35 57 31 65 / 70 40 20 10
DLN 38 60 39 69 / 60 30 10 10
HVR 47 63 44 72 / 80 30 30 30
LWT 44 57 41 66 / 90 60 30 40