Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 301800

Area Forecast Discussion
National Weather Service Great Falls MT
1200 PM MDT MON MAY 30 2016

.Aviation Section Updated...

.DISCUSSION...Cold front associated with today`s upper level
disturbance as push as far sound as Great Falls currently. Showers
and very isolated thunderstorms are scattered across the area.
Widespread scattered showers and isolated thunderstorms look to
remain possible today...mainly from just north of Helena to
Lewistown and north. Shower activity does not look to be an all
day event for most areas...with more periods of rain expected. For
SW portions of the CWA...cold front does not make it to SW MT
until tonight. By then most the moisture with this system will be
exhausted. So expect mainly dry conditions...with only isolated
late day showers. Areas that see the cold frontal passage will
struggle to get to near normal highs. Elsewhere could see highs
in the low to mid 60s. Storm qpf totals keep trending down...with
now only 0.1 to 0.25 inches expected today through Tuesday...with
isolated higher amounts possible. Anglin


An area of low pressure over southern Saskatchewan will continue to
move slowly ESE along the US/Canadian border over the next 24 hrs.
At the same time, the low will drag a cold front across central and
SW MT through tomorrow. Showers and a few TSRA accompanying the
front will mainly impact north-central Montana TAF sites while
KHLN/KBZN will likely remain mostly dry. Of note, though, due to the
limited instability expected, the confidence of TSRA at any TAF site
is very low. Drier air aloft will work in later today with shower
activity diminishing from NW to SE by tonight. However, wraparound
moisture will keep low clouds and SHRA going from KHVR to KLWT
through Tuesday morning, and possibly as far west as KGTF. MVFR CIGS
and occasional mtn obscurations will be the most predominate in the
vicinity of KGTF/KHVR/KLWT through Tuesday morning, with
predominantly VFR conditions expected elsewhere. In addition, a
gusty NW developing at KHVR/KLWT will continue on into Tuesday
morning as strong low to mid level winds mix down to the SFC on the
backside of the low. Martin



Today through Wednesday...Upper trof will continue to swing across
the area today dragging an associated cold front with it.
Scattered showers will continue to develop over central and
northern Montana early this morning with showers and isolated
thunderstorms increasing in areal coverage late this morning and
into the afternoon. Northwest winds will also become gusty this
afternoon and continue through Tuesday. Expected precipitation
totals remain in the tenth of an inch to a quarter inch range and
will be concentrated in the eastern portions of the county warning
area. The upper trof moves to northeast Montana overnight and
showers will begin to end from west to east. An upper ridge begins
to amplify over the west coast on Tuesday bringing drier
conditions to western Montana while lingering showers and gusty
winds persist in the east. 500mb heights rise Wednesday and a
brisk westerly flow aloft will continue the drying and warming
trend. Temperatures will be below seasonal averages to start the
week but afternoon readings should climb into the 70s by midweek.

Wednesday night through Monday...The period begins with a
brisk westerly flow aloft. Ensemble solutions reveal a bit of spread
amid this pattern as shortwave energy crosses southwest Canada.
Isolated afternoon showers cannot be ruled out, mainly over higher
terrain. Breezy west winds are expected to develop Thursday
afternoon and evening as a surface trough moves away to the east. By
Friday the ensemble solutions tighten up as a broad and nearly
stationary ridge strengthens over the western United States. This
ridge will maintain well above average temperatures through Monday.
Ensemble solutions finally begin to diverge late in the period as a
trough moves into northern California, creating a slight chance for
showers over southwest Montana early next week. PN


GTF  59  40  62  42 /  50  40  20   0
CTB  55  38  61  40 /  50  20  10   0
HLN  65  42  65  44 /  20  10  10   0
BZN  63  36  64  38 /  30  10  20   0
WEY  57  32  57  34 /  10  10   0  10
DLN  64  37  65  40 /  20   0   0   0
HVR  55  45  62  42 /  40  60  40  10
LWT  57  41  58  40 /  40  40  40  10



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