Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 211516

Area Forecast Discussion...Updated
National Weather Service Billings MT
916 AM MDT SUN AUG 21 2016


Models continue to show a little energy moving across southwestern
Montana this afternoon. While it will be very limited, cannot
rule out some convection developing during the afternoon. Given
the limited moisture available, in anything does form the activity
will likely be dry and on the western side of the Gallatin
Mountains. have left the slight chance PoPs in the very
southwestern Park Co. for this afternoon. The rest of the
forecast also looks on track, so will not need to do any updates.


.SHORT TERM...valid for Tdy and Mon...

Heights build into the area today as a ridge slides in. This
ridge will be flattened out by a strong shortwave trough moving
into British Columbia. This will serve to increase mid level
downslope flow, leading to warmer temperatures today and Monday.
Highs will move back to the lower 90s today and lower to mid 90s
on Monday. Weak shortwave energy is progged to push into western
zones this afternoon. Moisture was very limited with this feature
and was all above 700mb. MUcapes run to around 400j/kg over the
southwest mountains. Models were generally dry, but there was a
hint of some lift south of Livingston, so added low PoPs over the
far southwest for this. For Monday, heights lower and this allows
slightly stronger energy to get into the west. Moisture remains
very limited, and in fact, precipitable water amounts fall to
around a third of an inch. A cold front will move into the west
and this should enhance low level lift, but may not be enough to
overcome limited moisture. Kept low PoPs in place over the
southwest mountains, but scaled back due to falling PWATs. TWH

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

Little in the way of changes for the extended forecast period. The
early portion of the period remains pretty consistent...with cold
front followed by persistent cool northwest flow through about
Thursday. Models diverge somewhat from Thursday onward.

Upper low is progged to slide east across southern Canada and into
northwest North Dakota tuesday night...bringing cold front across
the CWA. Moisture availability is looking a bit better in latest
model runs for Tuesday evening and overnight. Another wave will
rotate through the region Wednesday evening bringing a bit better
chance for widespread moisture continues to slowly
increase in northwest flow and temps remain cool.

Although models tend to agree in broad terms on a continuation of
an unsettled pattern for the latter half of the
period...differences from Thursday on make for difficulty in
making any reasonable adjustments to going forecast. Currently
Saturday and much of Sunday look some degree of
shortwave ridging slides across the region. Otherwise shortwaves
crossing the region point to chances for precip each day...but
timing issues make for broadbrush type pops at this time.

Cold front Tuesday will introduce markedly cooler temps through
the work week...with persistent northwest flow over the area.
Wednesday appears to be the coolest day...with temps struggling to
reach 70 degrees. Weekend temps will climb back into the 80s
across the region. AAG



VFR will prevail across the area this afternoon through Monday
morning. Expect surface wind gusts to 25 kt around KLVM this
afternoon. A dry cold front will reach KLVM around 18Z on Monday,
bringing a shift to gusty W winds. Arthur



    Tdy Mon     Tue     Wed     Thu     Fri     Sat
BIL 091 058/091 055/078 051/069 048/071 050/075 052/081
    0/U 00/U    21/U    12/T    22/W    22/T    22/W
LVM 092 051/090 046/077 045/069 043/070 043/075 045/081
    0/U 02/T    21/U    22/T    22/T    22/T    21/B
HDN 092 057/093 055/080 050/071 047/073 049/078 051/083
    0/U 00/U    21/U    12/T    22/W    22/T    22/W
MLS 091 058/094 058/079 053/070 049/074 052/079 053/083
    0/U 00/U    21/U    11/N    11/B    22/T    22/W
4BQ 090 057/094 058/079 051/068 047/072 052/076 052/082
    0/U 00/U    11/U    11/B    11/B    22/T    22/W
BHK 087 055/094 055/077 050/067 045/071 048/075 050/080
    0/U 00/U    11/N    11/N    11/B    22/T    22/W
SHR 091 054/092 052/079 048/068 044/071 045/075 048/081
    0/U 00/U    11/U    12/T    22/T    22/T    22/W




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