Area Forecast Discussion Issued by NWS Great Falls, MT
000
FXUS65 KTFX 240949
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
349 AM MDT Fri May 24 2013
.DISCUSSION...
Friday through Sunday...Friday afternoon and Saturday continue to
show a decrease in widespread precipitation the upper level trough
retrogrades back towards the Canadian Coast. More shortwave
troughs will move across the area...however they appear relatively
weak...and more like to cause scattered showers than widespread
precipitation. Have increased the chance for showers and
thunderstorms Sunday morning and afternoon as models show another
decent shortwave trough moving through the area. Exact placement
of the disturbance is not in great agreement so have trended pops
still in the chance and slight chances across much of the area
with the highest percentages along the Rocky Mountain Front and
other higher terrain where the topographical enhancement could be
enough to help initiate convection. Temperatures remain near
seasonal averages as the drying trend helps temperatures rebound
for the first half of the weekend. Suk
Sunday night through Friday...The period begins with a persistent
upper trof over the Pacific Northwest. Short wave energy rotating
out from the base of the trof will continue to ride the southwest
flow aloft into the state. Scattered showers and thunderstorms will
continue to develop through Monday. By Tuesday, the models bring
another upper trof across the Rockies. Lift and diffluent flow aloft
will be strongest over southwest Montana Tuesday afternoon resulting
in another round of showers and thunderstorms. Isolated convective
activity will be possible across central and northern portions of
the county warning area. The remainder of the period, Wednesday
through Friday, will be characterized by continued unsettled
conditions as the area remains under the influence of a broad upper
trof. Temperatures will remain generally above seasonal averages to
start the period with readings dropping below seasonal averages by
the end of the week.
&&
.AVIATION...
UPDATED 0500Z.
An upper disturbance will move northeast through the area late
tonight and Friday morning. Expect showers/rain ahead of the
disturbance. Most locations will see a period of MVFR or possibly
even IFR ceilings and visibilities in the precipitation. Along with
the lower conditions expect areas of mountain obscurement. Conditions
will improve to scattered clouds after the passage of the upper
disturbance and gusty downslope winds will develop over the plains.
Blank
&&
.HYDROLOGY...Widespread rain and high elevation snow will continue
at times through Friday morning. Snow levels should lower enough
to lessen the impact of moderate precipitation on the remaining
mtn snowpack in these areas, however local streams and rivers
could see delayed rises through the upcoming weekend. Persons
living near or planning activities near the mentioned areas during
the holiday weekend should be alert for rising river levels and
increased stream flows.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 65 38 69 42 / 30 10 10 20
CTB 61 37 66 39 / 30 10 10 20
HLN 64 40 70 45 / 30 10 20 20
BZN 66 36 72 41 / 50 10 20 10
WEY 59 33 67 38 / 10 0 10 10
DLN 62 37 70 42 / 30 10 30 20
HVR 69 41 74 44 / 60 10 10 40
LWT 64 40 69 45 / 50 10 20 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...EMANUEL
AVIATION...EMANUEL
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