Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 220108
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
708 PM MDT Fri Apr 21 2017

.UPDATE...
Issuing an early update to raise PoPs/QPF a bit in accordance with
latest observed trends. Mainly utilized the SREF as it seems to
have the slowest downward trend in precipitation coverage. There
are no other significant changes with any other weather
parameters, though we will continue to monitor for fog potential
later tonight. Cassell

&&



.AVIATION...
Updated 2325Z.

Mainly VFR should prevail across Southwest MT as a weather
disturbance exits to the east and a high pressure ridge builds-in
from the west. For North-Central MT, scattered showers and MVFR CIGS
over much of the region should gradually exit the area to the east
over the next 12-hours or so and be followed by VFR. Patchy fog may
also develop overnight tonight and persist through about daybreak
Saturday, reducing VSBY to IFR or lower. However, confidence in fog
at any of the North-Central MT terminals is very low.
Jaszka

&&

.PREV DISCUSSION...
/ISSUED 525 PM MDT Fri Apr 21 2017/

Rest of Today through Saturday Night...Latest water vapor imagery
shows a weak mid-level low over central/southwestern at this time.
Lift and convergence within this low is keeping areas of generally
light rain/snow going across part of the area at this time. However,
there has been a noticeable decrease in the coverage of precip over
the past several hours and this trend should continue as the mid
level low shifts SE tonight. In its wake, high pressure will build
in at the surface with decreasing winds. With lingering moisture and
light winds tonight, the main concern will be low clouds/fog. Low
clouds may tend to limit fog development, but any area that clears
out could see patchy dense fog quickly develop with visibility
reduced to less than a mile at times, especially from Midnight
through early Saturday morning and primarily in areas that saw
heavier precip amounts over the past 24-36 hrs. For now, we`ll hold
off any dense fog products, but this will be closely monitored
tonight. In the mountains, additional very light snow accumulations
are likely through early this evening, but significant impacts are
not expected. Martin

Sunday through Friday...Overall an unsettled weather pattern will
reside over the region through much of next week. Precipitation
chances will increase once again on Sunday/Monday as the next
upper level disturbance moves across the Intermountain West. For
Tuesday and Wednesday, a stronger upper level disturbance will
move through the region during the afternoon hours on both days,
resulting in a fairly good chance for scattered showers,
especially over Southwest MT. During the overnight hours, the rain
could change to snow, especially for elevations above 5500 feet.
For Thursday and Friday, an upper level trof will still be over
the region. The chances for precipitation will be lower, but can`t
be ruled out at this point. In terms of temperatures, generally
seasonable to slightly below normal afternoon temperatures are
expected through the week. Brusda/Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  61  38  56 /  60  20  10  60
CTB  29  57  38  56 /  20   0  20  40
HLN  31  63  40  58 /  40  10  10  50
BZN  29  61  37  58 /  50  20  10  50
WEY  20  48  29  50 /  30   0  10  40
DLN  28  58  39  57 /  10   0  10  50
HVR  37  58  38  58 /  50  20  10  50
LWT  32  56  38  57 /  80  30  10  60

&&

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

$$

weather.gov/greatfalls


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