Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 241524

Area Forecast Discussion
National Weather Service Billings MT
924 AM MDT Sat Aug 24 2019


Timing for showers and storms remains similar. However, confidence
has increase for isolated thunderstorms to occur at and west of
Yellowstone County this evening. Although weak instability and a
relative lack of moisture will be present, an approaching jet,
ample shear, and helicity will be present to help briefly spin up
storms from 700 PM MDT through midnight. Vertz


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

Slow-moving upper trof over eastern MT/WY continues to bring some
showers w/ isolated TS to our far east early this morning. This
activity should diminish by 12z as trof continues to weaken and
shift east. Boundary layer is quite moist as skies clear from west
to east behind this wave. Fog has recently developed at the
Sheridan airport, and we still expect localized valley fog across
the east half of our cwa over the next few hours. Have made some
minor adjustments to wx and sky cover for the latest trends.

Satellite imagery shows an increase in high cloud as a result of a
developing Pacific flow and shortwave in NW Montana. Looking
further upstream, there is another wave approaching the PacNW
coast. It is this secondary wave which should allow for some
benign shower activity to begin to develop by late afternoon
across our west and north. Greatest potential for showers and
non-severe t-storms is tonight into early Sunday as this wave and
another cold front move west to east thru the region. 00z models
are spread in their QPF fields, but there is ascent and
instability w/ the shortwave, and GEFS plumes suggest some light
precip in the 00-12z time frame, so will keep mainly scattered
pops tonight...for up to a tenth of an inch of rain.

Modestly breezy NW winds will develop on Sunday behind this wave.
Next shortwave in a developing northwest flow aloft arrives by the

Temperatures today will rise back to the mid 80s to near 90 ahead
of the next cold front. Sunday will be several degrees cooler with
highs mainly upper 70s to low 80s.


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

Broad cyclonic flow will prevail across our region to start the
week. Weak unstable waves within the flow will lead to some
scattered or isolated showers Sunday night through Monday. The
northwest flow will turn drier and more anti-cyclonic the
remainder of the work week with just some weak Pacific impulses
producing isolated convection, primarily over the mountains and
foothills. The best chance of showers appears to be around Friday
when a stronger Pacific disturbance crosses our region. Highs will
be on the cool side with readings in the 70s to around 80
degrees for the work week. Ensembles then hint at ridging next
weekend leading to a modest warm-up with highs in the mid 80s. BT



VFR will prevail across the area today with scattered showers and
a few thunderstorms impacting the region late this afternoon
through tonight. Brief reductions due to thunderstorm activity are
possible. Mountains may be occasionally obscured. STP



    Tdy Sun     Mon     Tue     Wed     Thu     Fri
BIL 088 059/082 053/075 049/074 049/080 052/078 053/079
    1/B 51/U    11/U    10/U    00/U    11/U    11/B
LVM 085 050/081 044/074 040/076 043/082 046/081 046/080
    1/B 20/U    10/U    10/U    01/U    11/U    21/U
HDN 088 057/081 051/073 047/072 046/078 050/077 051/078
    1/B 31/U    21/U    10/U    00/U    11/U    11/B
MLS 087 060/080 052/071 047/069 046/075 049/075 049/075
    2/T 51/U    22/T    20/U    00/U    10/B    11/B
4BQ 086 059/080 051/072 046/069 045/075 048/075 049/074
    0/B 32/T    31/U    21/U    00/U    11/U    21/B
BHK 086 059/079 051/070 045/067 044/073 046/072 044/072
    2/T 44/T    23/T    20/N    00/U    10/B    11/B
SHR 087 054/081 048/073 043/071 044/077 048/078 048/078
    1/B 11/U    40/U    11/U    10/U    11/U    22/T




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