Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/03/21
Area Forecast Discussion
National Weather Service Great Falls MT
748 PM MDT Fri Apr 2 2021
.SYNOPSIS...
It will remain breezy, dry, and warmer than normal across the region
through the weekend, with the grassland fire danger remaining
elevated. A Pacific weather system then brings the next chance for
precipitation to start the work week, mainly to central and
southwest Montana, with mainly mountain snow and valley rain.
&&
.UPDATE...
Elevated Fire Weather concerns continue. Winds are a bit slower to
relax for the night than originally forecast; therefore, I have
increased winds and wind gusts to bring them in line with current
observations, and then, gradually decreased them over the next few
hours, interpolating to the 05Z grid. Other than winds, the
forecast is working well; so, no further updates will be made, at
this time.
- Fogleman
&&
.AVIATION...
513 PM MDT Fri Apr 2 2021 (03/00Z TAF period)
Expect VFR conditions throughout this TAF period. Widespread gusty
winds are forecast. Light aircraft experience impacts, especially,
near mountains and through passes.
- Fogleman
Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.
&&
.PREV DISCUSSION...
/ISSUED 513 PM MDT Fri Apr 2 2021/
This evening through Sunday...A westerly flow aloft keeps the
area dry and breezy with above normal temps through the weekend.
A series of disturbances in the flow will move weak, but dry,
frontal boundaries east across the area, which will help translate
gusty westerly winds down to the surface, mainly during the peak
heating/mixing period of the afternoons. While RH values have been
well into the teens this afternoon, winds to Red Flag criteria
have been much more patchy in nature. A similar setup is likely
Saturday, but mainly high level cloudiness over the area may limit
how much things dry out on Saturday and Sunday. Winds on Sunday
look to be more uniformly stronger across at least central and
north-central MT, and perhaps into Southwest MT as well, thanks to
low pressure passing to the north and high pressure to the south
giving us a respectable pressure gradient. RH values will be
marginal, however, so in coordination with GGW and SPC, it was
decided to hold off on a Fire Weather Watch for now. Lower
elevation areas will mostly have highs in the 60s and lows in the
mid 30s to lower 40s, while mountain areas will have highs in the
40s and 50s with lows in the 20s.
Sunday Night through Tuesday...Forecast models agree on bringing a
low pressure trough south out of the Gulf of Alaska today that
will likely move through the Pacific Northwest and Northern
Rockies through this period. While there remains some disagreement
on the exact strength and location of the main portion of the
system, models do appear to be gradually coming into alignment.
As of now, the model blend consensus focuses the best chance for
precipitation along and west of the Continental Divide Sunday
evening, then more so over central and southwest Montana (mainly
along and south of a Great Falls to Lewistown line) Monday into
Monday evening. POPs were increased some over the NBM defaults,
mainly over SW MT, in coordination with MSO, given the increasing
agreement and confidence. It should mostly be a mountain snow/
lower elevation rain event, but rain mixing with or changing over
to snow at times at lower elevations is very possible. The main
area of wet accumulating snow should be above 6500 feet, and
possibly on some mountain passes. The passage of this system will
also likely cool temperatures back closer to normal. The system
should start exiting the area later in the day on Tuesday.
Wednesday through next Friday...The area will mostly be between
weather systems Wednesday and Thursday. However, a lingering
unsettled flow aloft could cause some showers to form over the
mountains, as daytime heating will likely warm temperatures back
above normal and create some weak instability. Forecast models
indicate that the next system to impact the area could move in for
Friday, but remains substantial disagreement on the timing and
strength of it, so will maintain Chance POPs under 50% across the
area. -Kredensor/Coulston
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 38 70 40 68 / 0 0 0 10
CTB 32 62 36 59 / 0 0 0 10
HLN 39 72 41 68 / 0 0 0 10
BZN 35 71 38 69 / 0 0 0 0
WYS 22 61 25 58 / 0 0 0 10
DLN 34 69 37 67 / 0 0 0 0
HVR 36 67 42 68 / 0 0 0 10
LWT 37 68 38 67 / 0 0 0 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls