Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 301619

Area Forecast Discussion...Updated
National Weather Service Billings MT
1019 AM MDT SAT JUL 30 2016


Early morning shower activity has dissipated and been removed
from the forecast. updated afternoon and evening forecast for a
more widespread isolated thunderstorm potential. Best chance for
a storm or two today will be along the southern state line where
terrain influences will assist lift. However models showing a
weak h7-5 vorticity center shifting across the area this afternoon
along with a bit more mid level moisture advection. This combined
with steepening mid level lapse rates and somewhat stagnant low
level 45-55 degree dew points to be mixed upward should be enough
for a few high based storms during the heat of the day. Otherwise
forecast is on track with highs in the 90s...mostly sunny skies
and relatively light winds. Chambers


.SHORT TERM...valid for Tdy and Sun...

Weather for today and Sunday look relatively similar...generally
hot and mostly dry. Flat ridging with the flow turning slowly to
the southwest as a sharp trough drops south into British Columbia
and tracks into Alberta. This will generate a weak cold front that
will cross our CWA Sunday. The timing of this feature could set up
a chance of stronger convection toward the Montana/Dakota border
late Sunday due to combination of strong surface convergence and
instability/moisture in this area. Elsewhere...Minor perturbations
in the 500mb fields each day suggest some weak monsoonal energy
may produce some showers/thundershowers over and near the high
country from the Absarokas/Beartooths to the Big Horns. I would
expect convection to be somewhat more active on Sunday than today
due to the weak frontal passage. BT

.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...

No major changes were made to the extended with this forecast
package. Weak ridging builds across the forecast area Monday into
Tuesday. A strong upper low and trough move onto the Pacific
northwest coast Tuesday resulting in a southwest flow aloft. This
low is progged to move east along the Canadian border Tuesday and
Wednesday. As this low moves east, it will sweep a strong cold
front across the forecast area. Models are timing this front
across our area sometime during the evening and overnight hours

Southwest winds ahead of the front Tuesday will allow for good
compressional warming resulting in Tuesday being the warmest day
in the extended with temperatures well into the 90s and possibly
approaching 100 degrees for some locations. Tuesday will also be
about the only day with shower/thunderstorm chances so we will
continue with a slight chance across the entire forecast area.
Winds will abruptly shift to the northwest and be gusty along and
behind the front Tuesday night with gusty winds continuing into
Wednesday. Temperatures will cool to more seasonal levels

Dry conditions are expected Thursday and Friday with the
exception of thunderstorm chances over the mountains. Temperatures
will be seasonal Thursday before warming above normal Friday.


Isolated late afternoon thunderstorms are possible across much of
the area, lingering into the evening hours. Otherwise VFR
conditions can be expected today through tonight.



    Tdy Sun     Mon     Tue     Wed     Thu     Fri
BIL 096 064/096 060/090 062/096 060/085 055/085 058/090
    2/T 21/U    21/U    12/T    21/B    11/U    11/U
LVM 097 054/095 048/090 054/093 050/083 047/084 048/090
    2/T 21/U    21/U    12/T    21/U    11/U    11/U
HDN 097 062/097 058/093 061/099 060/086 055/087 058/092
    2/T 21/U    21/U    12/T    21/B    11/U    11/U
MLS 095 066/098 064/092 065/098 064/086 057/085 060/092
    1/U 11/U    11/U    12/T    21/U    11/U    11/U
4BQ 096 065/100 064/092 064/099 064/087 056/086 060/091
    2/T 22/T    21/U    12/T    21/U    11/U    11/U
BHK 091 061/097 060/089 061/094 062/084 055/083 056/087
    1/U 13/T    21/U    12/T    21/U    11/U    11/U
SHR 096 059/097 057/090 059/095 058/085 052/085 054/089
    2/T 21/B    21/U    12/T    21/U    11/U    11/U




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