Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 240236

Area Forecast Discussion...Updated
National Weather Service Billings MT
836 PM MDT TUE AUG 23 2016


Minor update to wind speeds and cloud cover tonight. Secondary
cold front is working through the area at this time as surface low
deepens over the southern Bighorn basin. Wind gusts have decreased
some since early evening, but upstream winds and continued
pressure rises hint at winds continuing to be gusty at times for a
few more hours especially over higher hilltop and foothills
locations and adjusted forecast to reflect this. Cloud cover is
filling in over northwest sections of the forecast area behind the
front indicating the arrival of cooler and moister airmass from
Canada. Increased cloud cover just a bit for these areas. Can`t
completely rule out a light shower/sprinkle for area west of a
Roundup to Billings line by sunrise but models really don`t want
to wring any low level moisture out of this system so kept going
dry forecast. Rest of the forecast on track with lows in the 45 to
55 range central and east...with a bit cooler in the western
valleys/mountains. Chambers


.SHORT TERM...valid for Wed and Thu...

Upper level low over Saskatchewan with flow aloft to be
northwesterly cyclonic for the next two days as the low moves
eastward and is replaced by a weaker wave for late Thursday.
However the atmosphere is not very moist so while this pattern
looks like it would support upslope shower activity it should not
produce a lot of precip but will generate an early fall cool
down. Satellite imagery this afternoon shows a stronger cold
frontal push moving into north central Montana accompanied by
higher humidity and low clouds. Ahead of this front its a very
breezy and dry afternoon with rh in the low teens and winds of 20
to 30 mph. Expect a transition between the airmasses to occur
between 8 pm and midnight tonight with winds subtly shifting from
northwest to northerly.

Wednesday will be even cooler with increased cloud cover but
precipitation will favor foothills and mountains over western
areas during the day as orographics will combine with steep lapse
rates aloft to generate showers and isolated thunderstorms. High
temperatures will be capped to the 60s and north winds will
persist for another day but expect minimum humidity to be closer
to 40 percent. Wednesday night better chance for shower activity
shifts to the eastern end of the Beartooth / Absaroka mountains
and the Big Horns. This persists into Thursday with continued
cool conditions but less wind. Precipitation looks like it will
avoid most of the low elevation areas but southeast Montana does
have a better chance Thursday night as moisture transport improves
into the area. Borsum

.LONG TERM...valid for Fri...Sat...Sun...Mon...Tue...

A broad trof will be in place over the region on Friday giving
slight chances for showers and isolated thunderstorms through the
early afternoon and evening. The best chances will be over the
higher terrain. Temperatures will warm into the lower 70s with
light winds prevailing.

The trof pushes east quickly Frida night and broad southwest flow
aloft should prevail over the region through the week. Several
weak disturbances will pass through northern Montana during the
week. Rain chances look pretty slim through the extended as
southwest winds aloft encourage downslope flow off the higher
terrain to the west. As these disturbances pass to our north,
surface winds will briefly turn northerly and then return back to
dry westerlies ahead of the next disturbance in the line.
Temperatures will warm through the weekend and level off in the
upper 80s by Sunday. With warm and dry conditions likely through
next week, fire concerns will increase with the warming
temperatures. Dobbs



VFR ceilings will increase over the western half of the forecast
overnight with perhapse an isolated light shower into the early
morning period. Northerly winds gusting 20 to 30kts will slowly
diminish overnight as surface high pressure builds in from the
north. Gusty winds will return for Wednesday. Chambers


    Wed     Thu     Fri     Sat     Sun     Mon     Tue
BIL 051/068 048/070 050/073 051/085 056/088 056/085 056/085
    01/B    11/B    12/T    11/U    11/U    11/B    11/U
LVM 044/066 041/068 041/073 045/084 049/086 048/085 048/084
    12/T    22/W    12/T    11/U    11/U    11/B    11/B
HDN 049/070 046/073 048/075 048/086 055/089 054/088 055/087
    01/B    12/W    12/T    11/U    11/U    11/B    11/U
MLS 053/068 047/073 051/076 052/085 057/090 057/087 057/087
    01/N    10/B    12/T    21/U    11/U    11/U    11/B
4BQ 051/068 046/070 049/074 051/084 057/088 056/087 058/087
    01/B    11/B    23/T    31/U    11/U    11/U    11/U
BHK 050/066 044/070 047/073 048/081 053/086 054/085 054/085
    01/N    11/B    23/T    31/U    11/U    11/U    11/B
SHR 048/068 044/069 044/073 046/083 051/087 050/087 053/086
    01/B    23/T    22/T    21/U    11/U    11/U    11/U




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