Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 300504
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1100 PM MDT Tue Jul 29 2014

.UPDATE...
Very isolated areas of showers and a weak thunderstorms or two,
mainly over parts of southwest MT, continue to steadily dissipate.
Should see the remaining convective activity end by midnight, though
a few weak showers may linger over the MT/ID border south of Dillon
into the wee hours of Wed. Overnight low temperatures (mid-50s to
around 60 at lower elevations) will be a few degrees above normal
again tonight as the stationary high pressure ridge keeps the warm
airmass in place across the region.
Waranauskas

&&

.DISCUSSION...
Tonight through Thursday...The strong upper ridge will continue
over the western U.S. with the axis of the upper ridge going
through western Montana. Do not see any significant weather
disturbances aloft during the period and moisture will be somewhat
limited but afternoon heating will lead to thunderstorms which
should diminish overnight with the loss of heating. Although no
severe thunderstorms are expected through Thursday there could be
gusty winds with them. For southwest Montana expect isolated to
scattered thunderstorms this evening and again Wednesday afternoon
and evening. Expect a little more activity Thursday as instability
increases slightly. To the north northerly flow aloft should keep
thunderstorms pretty close to the mountains this evening. As the
flow aloft turns more westerly and increases by Thursday
thunderstorms will have a better chance of moving off the
mountains. Also by Thursday afternoon a surface trough over the
plains could also contribute to the development of thunderstorms.
Blank

Thursday Night through Tuesday...An unsettled weather pattern
will prevail during the extended forecast period. The combination
of Monsoonal moisture and weak shortwaves propagating through a
broad upper-level ridge will result in at least a slight chance
of showers and thunderstorms each day. Despite the increased
chance for precipitation, forecast confidence is low regarding
precipitation coverage/amounts as the timing of these shortwaves
and associated moisture remains uncertain. Latest forecast models
suggest that the best chance for precipitation will be Saturday
as a stronger shortwave trough moves across the Treasure State and
flattens the upper-level ridge. High temperatures in the low 80s
to low 90s Friday will lower to the lower to mid 80s this upcoming
weekend. MLV/JMB

&&

.AVIATION...
UPDATED 0500Z.
VFR conditions will prevail. Pockets of monsoonal moisture will
produce isolated showers and a few short-lived thunderstorms after
20Z Wednesday at KBZN/KHLN. Easterly low-level winds and northerly
mid-level winds should keep storms away from KGTF/KCTB/KHVR/KLWT.
Convection should dissipate after 06Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  60  90  59  90 /  10  10  10  20
CTB  56  90  55  89 /  10  10  10  20
HLN  60  92  59  92 /  20  20  20  30
BZN  53  87  53  87 /  20  20  20  30
WEY  42  76  40  77 /  20  40  40  40
DLN  53  83  52  84 /  20  30  30  40
HVR  57  95  57  95 /  10  10  10  10
LWT  55  89  56  90 /  10  10  10  10

&&

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

$$

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