Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 290449
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 PM MDT Thu Aug 28 2014

UPDATED AVIATION SECTION

.DISCUSSION...
Update forthcoming. Upper trof and surface cold front will continue
to move across the area overnight. Showers and isolated
thunderstorms will move along the Hi-Line for the next several
hours. An area of showers and isolated thunderstorms also continues
to move across southwest Montana. Precipitation will continues to
move east overnight and will be mainly over eastern Montana by
daybreak. A few lingering morning showers over eastern Montana will
end by midday as shortwave ridging develops over the area.
Temperatures look good.

&&

.AVIATION...
UPDATED 0455Z.
A weather disturbance aloft will move through the forecast area
tonight. Expect scattered showers/isolated thunderstorms ahead of it
towards the Canadian border (KCB/KHVR) while over southwest MT
(KBZN)expect isolated showers/thunderstorms. Showers/thunderstorms
should end around 12z. The main problem tonight will be dealing with
MVFR/IFR ceilings. Confidence in ceiling forecasts over the plains
is low as some guidance has these lower ceilings while other
guidance keeps conditions VFR. Be aware that there could be local
MVFR/IFR visibilities as well. What low clouds there are early
Friday morning should dissipate between 15z-18z Friday. Friday
afternoon and evening expect clear skies to scattered clouds with
isolated thunderstorms possible south of a KBZN-KDLN line. Blank

&&

.PREV DISCUSSION...ISSUED 233 PM MDT Thu Aug 28 2014

Tonight through Saturday...Upper level disturbance and associated
surface cold front will push through North Central Montana
tonight. Isolated to scattered showers and thunderstorms are
expected over much of the forecast area this evening, but eastern
slopes of Glacier National Park should see a widespread light
rain. The remnants of the system will move east overnight through
Friday morning with weak shortwave ridging aloft developing by
afternoon. Friday`s high temperatures will be slightly cooler than
Thursday with partly cloudy skies and perhaps an isolated
thunderstorm in far Southwest Montana by late afternoon. Shower and
thunderstorm coverage will increase overnight and will spread into
Central Montana by Saturday morning. Showers and thunderstorms
will continue to develop in Southwest and eastern portions of
Central Montana for much of Saturday but only isolated showers are
expected over western portions of Central Montana. Temperatures
will continue to cool back toward seasonal averages. mpj

Saturday Night through Thursday...This period begins with scattered
showers behind the cold front lingering mainly over the southwest
counties and over toward Lewistown.  Slightly unstable conditions,
coupled with northwest flow aloft and residual moisture will also
produce isolated showers on Sunday along the Rocky Mtn Front and
over the southwest mountain ranges. A weak shortwave trof will move
quickly through our forecast area on Mon, bringing a fair amount of
cloud cover, but GFS and ECMWF models disagree on whether we`ll
actually see precipitation with the trof, so have kept just a slight
chance for showers from around Harlem to Dillon on Mon aftn/eve.
Tuesday and most of Wednesday looking dry at all locations as weak
high pressure ridging tracks through the state. By Wed night, the
next shortwave trof reaches central WA/OR and pushes a sharp cold
front east of the Continental Divide.  Widespread showers are
expected along/ahead of the front early Thurs morning and then
additional rainfall develops with the passage of the trof axis Thurs
night.  Current model runs are indicating rainfall amounts of a
tenth to one-half inch from the nighttime precipitation.
Temperatures remaining cooler than normal through the period.
Waranauskas

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  52  79  54  72 /  20  10  20  40
CTB  47  77  53  70 /  50  10  10  20
HLN  53  83  54  73 /  20  10  30  40
BZN  48  81  49  68 /  30  10  30  50
WEY  40  69  41  62 /  30  20  30  50
DLN  49  81  50  68 /  30  10  40  50
HVR  51  77  55  76 /  40  10  10  30
LWT  52  74  53  69 /  30  20  20  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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