Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 250926
Area Forecast Discussion
National Weather Service Great Falls MT
326 AM MDT Tue Apr 25 2017
Today through Wednesday...Mostly cloudy skies will persist across
the CWA and snow levels should continue to fluctuate between roughly
5000 and 6000 feet MSL. As one shortwave trough exits Southwest MT
to the south and east this morning, bands of steadier snow should
diminish over that area by late morning. The winter weather advisory
until noon today for southern Gallatin County was expanded to
include southern Madison and Beaverhead counties, including Raynolds
Pass and Monida Pass. Slick, snow-covered roadways should linger in
these areas this morning. Another shortwave trough will skirt the
international border and Hi-Line today as it also moves generally
southward and eastward. Accordingly, scattered showers are expected
with the passage of this disturbance, especially over North-Central
MT. In addition, isolated thunderstorms are possible late this
morning through early evening and may move slowly once again,
resulting in localized swaths of heavier rainfall. Subtle shortwave
high pressure ridging and boundary layer stabilization via nocturnal
cooling should result in drier weather later this evening into
Wednesday morning. Thereafter, the potential for scattered showers
and isolated thunderstorms will increase late Wednesday morning
through afternoon as another disturbance overspreads the CWA from
the west. Near-normal lows and slightly below-normal highs are
expected through Wednesday.
Wednesday night through Tuesday...An overall unsettled weather
pattern will reside over the region during the extended period.
Light rain from Wednesday afternoon will continue through Wednesday
night. The rain could change to snow by Thursday morning at lower
elevations. However, the latest models indicate some precipitation
to continue into the day on Thursday, but some breaks in the
precipitation are possible, especially along/west of I-15.
Scattered/likely areas of precipitation will then continue Thursday
night through Monday, with the lowest chance for precipitation being
Sat/Saturday night. By Tuesday of next week, the GFS model progs a
fairly deep upper level trof of low pressure to develop over the
region, resulting in a fairly good spring snowstorm over Central MT.
However, it is too early to feel confident in this storm at this
time. Otherwise cool afternoon temperatures on Thursday and Friday
will warm a touch over the weekend, only to cool a bit by next
Scattered showers will continue to be found across portions of
northern and central MT tonight...while rain and snow push into
southern portions. Some snow could even be found across lower
elevation sites briefly Tuesday morning...mainly from KCTB to
KGTF. MVFR to brief IFR conditions are expected under any rain or
snow shower tonight through Tuesday morning. Tuesday afternoon
will see shower activity become more scattered...with lower
elevation snow ending...and some thunderstorms possible across
much of the area. VFR to MVFR conditions can be expected Tuesday
afternoon. Shower activity then looks to diminish Tuesday
evening...with widespread VFR expected by the end of the period.
Mountain obscuration is possible through Tuesday morning...breaking
up Tuesday afternoon.
.PRELIMINARY POINT TEMPS/POPS...
GTF 49 33 54 36 / 50 40 40 60
CTB 44 31 51 35 / 80 60 50 60
HLN 53 35 55 36 / 50 40 40 70
BZN 48 31 53 34 / 80 40 50 90
WEY 38 21 40 27 / 70 30 60 90
DLN 49 33 51 32 / 50 30 50 80
HVR 48 32 54 36 / 30 30 40 50
LWT 45 30 50 33 / 40 50 60 70
Winter Weather Advisory until noon MDT today Beaverhead...