047
FXUS65 KTFX 161800
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1200 AM MDT Wed Oct 16 2013
UPDATED AVIATION DISCUSSION
.UPDATE...
Canadian cold front continues to push southward through the region
this morning. A band of light rain is accompanying the frontal
passage. Generally most areas will see less than a tenth of an
inch of precip today. Snow will generally fall above 7000 feet
with some light snow accumulations. Temperatures look on
track...with high temperatures likely occurring this morning over
North Central MT just ahead of the front. Other than a small
adjustment to pops...all else is on track for today. Brusda
&&
.AVIATION...
UPDATED 1800Z.
An upper level trough and surface cold front will continue to track
SE through North Central and SW MT today, exiting the region this
evening. Good coverage of rain showers follows behind the front/wind
shift to the north, which will spread farther south in the
KLWT-KBZN-KHLN areas this afternoon, though coverage will likely be
lesser in these areas. Occasional MVFR and isolated IFR possible in
showers through this afternoon with widespread VFR tonight as skies
clear behind the system. Hoenisch
&&
.PREV DISCUSSION...
/ISSUED 600 AM MDT Wed Oct 16 2013/
Wednesday through Friday...A quick moving cold front associated
with a shortwave trough will move across the area this morning.The
cold front is expected to move across the hi-line around 6 am
local time. Forecasts generally keep the frontal boundary a few
hours ahead of the precipitation as it moves south out of Canada.
The main area of precipitation will likely last less than 6 hours
as it moves quickly southward. Precipitation totals should be
limited to around one tenth of an inch due to the fast moving
nature of this system. However...locally higher amounts especially
over the mountainous terrain is possible. The largest amounts of
snowfall accumulations should be limited to the mountains along
the Northern Rocky Mountain Front including Glacier National Park.
However totals are still expected to remain below advisory
criteria. Central Montana can expected to see the wind shift from
the front around noon local time. The front will move across
Southwest Montana around sunset...with a more scattered
precipitation shield trailing over the region...widespread
precipitation is not expected over Southwest Montana. After the
system passes on Wednesday...the general flow remains out of the
northwest with the boundary between cyclonic flow...from the
large scale trough over the Great Lakes...and the the
anticyclonic flow...from the large scale ridge off the Pacific
Coast...overhead. This will lead to some lack of confidence over
temperatures and precipitation forecasts. The current forecast
ensemble keeps us under the building high pressure associated
with upper level ridge which will lead to warmer temperatures and
dry conditions aloft. However if the boundary sets up to our
east...as suggested by the ECMWF...we will be under cooler more
unsettled conditions. Have gone with the warmer drier conditions
as suggested by the consensus suite for remainder of the work
week. Suk
Friday night through Wednesday...The long term period will remain
under general northwest flow resulting from a ridge of high pressure
over the west coast. Models differ on its strength and position
which may result in some unsettled periods. Models indicate that
there will be some disturbances in the flow aloft over Montana but
continue to keep most of the energy and moisture over eastern
Montana. As a result, a dry forecast is in order into Sunday before
the chance of showers increases over terrain through Wednesday. Any
precipitation that does occur looks to be light overall. Forecast
confidence is fairly weak after Sunday with models disagreeing on
how much the ridge to the west influences the region. No significant
systems look to be moving towards the region throughout the period
though. Models continue to remain relatively warm through the long
term with highs nearing 60 in the lower elevations some days.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 46 30 48 33 / 70 50 10 10
CTB 44 28 49 31 / 80 20 0 10
HLN 51 30 50 31 / 50 30 10 10
BZN 48 28 44 27 / 20 30 10 10
WEY 42 23 39 21 / 10 20 10 10
DLN 50 27 47 26 / 10 10 10 10
HVR 48 29 51 31 / 80 20 10 10
LWT 46 27 42 29 / 60 70 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls