Area Forecast Discussion
Issued by NWS Great Falls, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KTFX 252059
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
259 PM MDT MON JUL 25 2016

.DISCUSSION...

Tonight through Wednesday...A shortwave trough embedded within
zonal flow aloft will move eastward over our CWA this afternoon
through Tuesday morning. Scattered showers and thunderstorms will
accompany this disturbance, especially before midnight tonight. The
best chance for this activity exists over and near higher terrain.
Strong wind gusts may accompany these storms.

On Tuesday and Wednesday, additional scattered showers and
thunderstorms are expected, especially in the afternoon and evening,
as two more eastward-moving shortwave troughs affect the region.
Convection will likely initiate over the higher terrain by early to
mid-afternoon of both days before moving generally eastward over the
nearby plains and valleys. Model soundings indicate moderate deep
layer shear, appreciable instability, and downdraft CAPE near 750-
1000 J/kg should yield some stronger storms capable of small hail
and strong to perhaps marginally severe wind gusts.

Most locations will have lows in the 50s and highs in the mid 80s
to lower 90`s tonight through Wednesday. Jaszka

Wednesday Night through Monday...Showers and thunderstorms look to
continue into Wednesday night as a strengthening LLJ brings fast
se flow into eastern portions of our CWA. A decent jet aloft and
modest cape values could support a few isolated stronger storms
for Wednesday evening and into the early overnight hours. Wind and
perhaps some hail will be the main concerns. Weak troughing will
continue across the area for Thursday...bringing a weak cold
front...and perhaps producing more isolated to scattered
thunderstorm activity across the CWA during the afternoon and
evening hours. Shear and abundant moisture will be lacking with
this front...making severe storms hard to come by. NW flow
transitions to more of a westerly and dry flow on
Friday...bringing warming and dry conditions. Models starting to
hint at the return of more monsoonal moisture than recently
thought for this weekend. This could bring isolated to widely
scattered thunderstorm activity Saturday...mainly across sw
portions...and possibly into central MT. Another round of
thunderstorms looks to be possible Sunday across much of the CWA
as monsoonal moisture continues...and a weak front moves across
the area. This front could then bring dry conditions...and
elevated fire concerns early next week...especially across
northern and western portions...with some lingering moisture
possibly producing a few isolated thunderstorms in eastern and
southern portions. Slight chances for pops were added in for the
weekend...however...confidence remains low on exactly how abundant
this monsoonal moisture will be. Temps will begin to warm
Thursday...and should be in the 90s this weekend. Slightly cooler
conditions in the mid 80s are then possible early next week behind
Sunday`s front. Anglin

&&

.AVIATION...
Updated 1724Z.

Primarily VFR expected through 18Z/Tue. Still expect some scattered
showers/TSRA to develop over the mountains during the early to mid-
afternoon as a weather disturbance approaches from the Pacific
Northwest. These storms will then move east-northeastward. Most
confident in brief thunderstorm activity impacting KCTB/KGTF/KLWT
early this evening. Brief MVFR and erratic wind gusts of 30-40 knots
are possible in/near any storm. As the disturbance moves eastward
over the area tonight into Tue morning, some additional isolated
showers/TSRA are possible, but confidence in any activity impacting
any terminal is very low. Jaszka

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  89  57  86 /  30  20  20  20
CTB  55  82  54  81 /  20  60  20  30
HLN  62  91  61  90 /  30  20  20  20
BZN  54  88  53  88 /  20  20  20  20
WEY  43  80  44  79 /  10  20  20  10
DLN  53  85  53  87 /  20  10  10  10
HVR  59  88  60  84 /  20  30  60  30
LWT  58  86  58  82 /  30  50  40  30

&&

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

$$

weather.gov/greatfalls


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.