Area Forecast Discussion
Issued by NWS Great Falls, MT

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783
FXUS65 KTFX 262319
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
515 PM MDT TUE JUL 26 2016

UPDATED AVIATION SECTION

.DISCUSSION...
Tonight through Thursday...An upper level disturbance continues to
push eastward through the region. Scattered showers/thunderstorms
continue to develop along this disturbance. The main threat from
the storms this evening will be brief heavy rain and lightning
strikes. Expect fairly similar conditions over the region on
Wednesday...with mostly quiet conditions in the morning followed
by scattered showers/thunderstorms in the afternoon/evening hours.
On Thursday, the flow aloft will shift slightly to the northwest
as the upper level ridge tries to rebuild over the Pacific
Northwest. On Thursday, expected thunderstorms to be more
isolated, as a weaker upper level disturbance moves through, with the
storms mainly affecting the eastern portions of the region.
Afternoon temperatures will generally be near normal Wed/Thu with
highs ranging from the mid 80s to lower 90s. Brusda

Thursday Night through Tuesday...The last in a series of shortwave
disturbances exits to the east Thursday night. Temperatures trend
back into the lower 90s Friday and Saturday amid a generally stable
westerly flow. However, isolated weak afternoon thundershowers may
be possible during this period over our northeast zones associated
with a weak baroclinic zone. A stronger weather system moves across
the Canadian Rockies Saturday night into Sunday, forcing a southwest
flow aloft over the region. This will help to draw monsoonal
moisture into southwest Montana, with enhanced chances for afternoon
showers and thunderstorms through the weekend. Temperatures trend a
few degrees cooler to start next week with lower heights over the
northwest and isolated to scattered showers. PN

&&

.AVIATION...
Updated 2315Z.

VFR conditions are generally expected over the next 24 hours. A
disturbance in the westerly flow aloft is moving over a very warm
and unstable airmass across the forecast area. Scattered showers and
thunderstorms have developed south of a KGTF to KLWT line, while
more numerous storms are north of this line. These storms will move
east across the area through 06Z with the disturbance, with storms
diminishing after 02Z from the west. The main overall threat from
these storms will be gusts in excess of 40 kt and brief heavy rain.
However, some of the stronger storms to the north may produce hail
up to penny size. The main threat for these stronger storms will be
northeast of a KCTB to KLWT line (which includes KHVR). After 06Z, a
few showers may move southeast along the Hi-Line, but clouds
elsewhere will generally diminish. Another weak disturbance may
bring another chance for thunderstorms to the area beginning after
18Z in the KCTB area.  Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  85  56  84 /  40  20  30  20
CTB  53  80  53  80 /  50  30  40  20
HLN  62  89  60  89 /  20  10  20  10
BZN  53  87  53  87 /  20  10  20  10
WEY  43  79  45  78 /  30  10  20  10
DLN  53  87  53  87 /  20  10  20  10
HVR  60  84  58  84 /  50  30  40  20
LWT  58  81  57  81 /  50  20  30  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

weather.gov/greatfalls



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