Area Forecast Discussion
Issued by NWS Great Falls, MT

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000
FXUS65 KTFX 262358
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
558 PM MDT Wed Jul 26 2017

...UPDATED AVIATION...

.SYNOPSIS...
A summer time upper level ridge of high pressure will generally
reside over the region for the next week or so. As a result,
expect above normal temperatures to prevail through at least early
next week. There will be a chance for a passing thunderstorm,
mostly today through Thursday night. Some of the stronger storms
could produce frequent lightning and strong wind gusts.

&&

.DISCUSSION...

This evening through Friday night...The summer time weather
pattern with a strong upper level ridge of high pressure over the
western US will continue. However, upper level disturbances will
rotate around the upper level high. As a result a few storms will
move northward into Southwest MT this afternoon and possibly as
far north as southern parts of central MT by this evening and even
into the overnight. On Thursday, expect similar conditions,
except a better chance for thunderstorms to move as far north as
the northern portions of central MT. The main threat from any of
the stronger storms still looks to be frequent lightning and
strong wind gusts. A few of the storms could be on the dry side as
well. By Friday, the upper level support for the storms will be
weaker, thus the chances for storms will be confined mainly to our
eastern and southern portions of the region. In terms of
temperatures, expect afternoon temperatures to generally average
about 4 to 8 degrees above normal for most locations through the
period. Brusda/Cassell

Friday night through Wednesday...Long range guidance still remains
in high confidence that strong ridging will build back into the
western U.S. through the forecast time frame. H5 height anomalies
will range well above-average for this time of the year. Given the
climatological norms, combined with abnormally high heights,
afternoon temperatures will easily soar to the mid to upper 90`s
areawide on Friday, lasting through the weekend and even into early
next week. Additionally, small and weak disturbances will attempt to
rotate around the northern periphery of the ridge which may allow
for some shower and storm chances, however widespread precipitation
looks to remain very unlikely. Under any storms that do develop, a
well-mixed and dry boundary layer will yield little precipitation,
with gusty winds and dangerous lightning the main threat.
Furthermore, given the drought situation areawide, any lightning
strikes may create new fire starts especially across central and
southern regions of the CWA. KLG

&&

.AVIATION...
Updated 0000Z.

A weak disturbance will bring isolated to scattered thunderstorms
this evening mainly south of a line from KHLN to KLWT...especially
in the KBZN and KEKS areas. Gusty winds around 30 knots and
frequent lightning will be the main threats. Otherwise...VFR
conditions with light winds will prevail through tonight and into
Thursday morning. Another round of thunderstorms are possible
Thursday afternoon and evening...mainly south of a line from KGTF
to KLWT. Gusty winds and frequent lightning will again be the main
threats...with VFR conditions expected. Area wildfires may cause
some smoke at times across the region during the forecast period.
Anglin

&&

.FIRE WEATHER...
Scattered showers/thunderstorms will move northward into Southwest
MT this afternoon and possibly as far north as Central MT by this
evening. The main threat from the storms will be gusty
winds/lightning. Expect similar conditions on Thursday, except a
better chance the storms will push northward well into the
northern portions of Central MT. Additionally, increased downslope
flow off of the Rocky Mountain Front looks to cause elevated fire
weather concerns during the day Thursday. Looking ahead...mostly
dry and hot conditions are still expected this weekend and into
the first half of next week. Brusda/Cassell

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  63  91  60  92 /  10  20  20  20
CTB  56  90  56  89 /   0  20  10   0
HLN  63  88  60  91 /  20  30  20  20
BZN  56  84  54  86 /  20  30  20  20
WEY  48  75  43  76 /  50  40  30  30
DLN  55  80  52  83 /  40  40  30  20
HVR  63  95  62  94 /  10  20  20  20
LWT  63  86  59  88 /  20  30  30  20

&&

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

$$

weather.gov/greatfalls


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