Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 251040
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
445 AM MDT WED MAY 25 2016

Aviation section updated

.DISCUSSION...

Today Through Friday...A weakening upper level low remains centered
over SW SK this morning with trough axis extending to the SW
through the Western US. The SK upper level low gradually sags
south today and tonight to a position along the MT/SK border and
continues slowly SE across NE MT Thursday. A somewhat moist NW
cyclonic flow aloft will remain across the forecast area through
Thursday with afternoon airmass destabilization resulting in a
greater coverage of showers and possibly a few weak thunderstorms
this afternoon and again Thursday. Temperatures through Thursday
will remain near to somewhat below seasonal averages. By Friday,
upper level energy now moving SE along the AK Panhandle will dig
into WA/ID, shifting upper level flow across the region to the SW.
A surface Pacific cold front associated with the incoming upper
level trough will likely cross the Continental Divide Friday for
increased chances for showers and thunderstorms by Friday
afternoon. Models differ some on the degree of instability ahead
of the front with GFS/GEFS indicating higher CAPE and a marginal
risk for stronger thunderstorms while the NAM/SREF is not as
aggressive in coverage of convection or its strength. Hoenisch

Friday night through Wednesday...A rather unsettled weather pattern
will continue to reside over the region through Tuesday, before
drier and warmer conditions start to move into the region by next
Wednesday. We will be in transition between upper level disturbances
from Friday night through Sunday night, with a chance for a passing
shower expected over the weekend. Right now, the precipitation
activity should be on the low side on Sunday, and pops have been
reduced a bit for this period. However, both the GFS/EC prog an open
trof moving through the region on Memorial Day. As a result, pops
have been increased a bit on Monday. Temperatures will remain a bit
below normal over the weekend, and than rather cool on Monday.
Additionally, some snow will be possible, especially for elevations
above 6000 feet during the late night/morning hours. For late Tue
into Wednesday, both the GFS/EC are showing a weak upper level ridge
of high pressure building over the region. This ridge will allow
drier and warmer air to move into the region, which will be a nice
change from current weather pattern. By next Wednesday, afternoon
highs will be near normal over the Southwest, and near/slightly
below normal over the North. Brusda

&&

.AVIATION...
UPDATED 1045Z.
Mostly clear/partly skies this morning will give way to scattered
light showers across region generally from 18z today thru 05z Thu. A
few isolated thunderstorms will be possible during this period as
well. Some mountain tops will be obscured...but the obscurations
should not be as widespread as the previous few days. Overall VFR
conditions will prevail...but some MVFR conditions will be possible
in/near showers. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  65  44  64  44 /  40  30  50  30
CTB  65  42  64  41 /  40  30  50  30
HLN  65  46  67  45 /  40  30  40  30
BZN  63  40  64  41 /  40  30  40  30
WEY  50  33  54  36 /  80  40  50  50
DLN  60  39  63  41 /  50  40  40  40
HVR  65  42  68  45 /  50  30  30  20
LWT  62  42  63  43 /  50  30  40  30

&&

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

&&

$$

weather.gov/greatfalls



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