Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 240307
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
907 PM MDT Sun Jul 23 2017

.UPDATE...
Shortwave was kicking across south central Montana, into
southeast Montana this evening. A few showers and thunderstorms
have accompanied this wave. Activity was not able to get much
footing over south central zones with lower dewpoints, but has
been able to be a little better organized as it moves into
southeast Montana with slightly higher dewpoints and an 850mb low
level jet feeding in. Adjusted PoPs over southern zones to
account for ending things over south central zones and becoming a
little more aggressive over southeast Montana. Will keep PoPs low
as coverage was not great at this time and high resolution models
keeps things limited. Most of the coverage will be in northeast
Wyoming, with with scattered coverage nosing up into the far
southeast corner of Montana. TWH

&&

.SHORT TERM...valid for Mon and Tue...

Break in the hot weather for a couple of days coming as a front
will push through the region early Monday morning. For this
evening a high level disturbance is moving across southern Montana
from east to west and convective response to this feature has
been very limited and only expect high based cumulus with a
possible thunderstorm over the higher terrain. This changes later
this evening as the disturbance works east and encounters a
different environment as the low level jet begins to strengthen
over eastern Montana. With 40 knots at 850 mb indicated moisture
is expected to deepen but ground is so dry suspect activity will
be fairly limited and produce limited moisture. This low level jet
could be a problem for any fires that develop serving to ventilate
the columns through the inversion but no large fire activity is
indicated at this time. Have higher pops for southeast Montana for
a couple of storms becoming thunderstorms.

Tomorrow a cold front moves through the area around daybreak for
the western zones and reaches the eastern zones by 1000. However
front is split and a second push of cooler air moves into the
eastern zones early afternoon. Second push will produce stronger
winds over the eastern zones during the afternoon but will pull
some higher humidity into the area. Front does bring slightly
cooler temperatures with warmest temps coming into between the two
features with the secondary push not as strong into the western
zones. Models indicate any convection will actually occur Monday
evening as the moisture has a chance to deepen but GEFS plumes
are very spotty with moisture as is the ECMWF.

Tuesday looks to be the coolest day in some time with heights
suppressed in the wake of an upper low traveling across southern
Canada. Highs only in the mid 80s with increased clouds as a
piece of monsoonal moisture streams into the area increasing
precipitable waters as persistent low level flow remains
northeasterly. Again the GEFS and ECMWF produce less precipitation
than operational GFS but lower levels will not be nearly as dry
so precipitation could hit the ground...but would not expect
amounts more than .05 anywhere. borsum

.LONG TERM...valid for Wed...Thu...Fri...Sat...Sun...

Upper flow on Wednesday and Thursday should be semi-zonal and then
turn a bit more anticyclonic Friday into Sunday. Models are
showing energy propagating through the flow over our area. This
energy can generate periods of isolated to scattered mainly high-
based showers and thunderstorms most days Wednesday through
Sunday. High temperatures will be near normal, in the middle 80s
to near 90 on Wednesday, then rise to the upper 80s to middle 90s
for Thursday-Sunday.

Overall...still no sign of a major pattern change. Models are in
good agreement that the general theme of warm, dry weather with
little rainfall looks to continue through at least the next week.
RMS

&&

.AVIATION...

Isolated thunderstorms will affect SE MT and the KSHR area late
this evening into the overnight hours. MVFR conditions are
possible for KMLS, KSHR and KBHK if a storm moves over these
locations. Otherwise a low-level jet will create areas of LLWS
over SE MT into Mon. morning. A cold front will push SE into the
area early Mon. morning, bringing a wind shift to the NW to KLVM,
KBIL and KMLS by 18z and to KSHR by early afternoon. Isolated
thunderstorms will develop over and near the mountains in the
afternoon with MVFR conditions. Arthur

&&

.PRELIMINARY POINT TEMP/POPS...

    Mon     Tue     Wed     Thu     Fri     Sat     Sun
-----------------------------------------------------------
BIL 066/092 063/084 061/088 064/091 064/093 064/094 064/093
    11/U    22/T    22/T    32/T    11/U    12/T    22/T
LVM 057/091 056/084 054/085 056/089 054/090 055/091 055/091
    11/B    22/T    23/T    32/T    11/U    12/T    22/T
HDN 062/094 063/087 060/090 063/092 061/095 061/096 061/095
    11/U    22/T    22/T    22/T    11/U    12/T    22/T
MLS 070/096 065/089 063/091 067/093 065/097 065/096 066/095
    00/U    21/B    11/U    22/T    21/U    11/U    11/U
4BQ 066/097 065/089 062/090 064/092 063/095 062/095 064/095
    30/U    21/B    21/B    23/T    21/U    12/T    22/T
BHK 066/097 061/087 058/088 061/090 062/093 060/094 062/092
    10/U    21/B    11/U    12/W    11/U    01/U    11/U
SHR 058/094 058/086 056/086 058/088 057/092 057/093 057/092
    31/U    23/T    43/T    33/T    21/U    12/T    22/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Fire Weather Watch in effect from Monday afternoon through
      Monday evening FOR ZONE 117.
WY...None.

&&

$$
weather.gov/billings


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