Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 180308
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
908 PM MDT SUN JUL 17 2016

.UPDATE...
Isolated ugly looking storms this evening that dont have very
good structure to them, but do have some nice rainfall rates and
probably spotty dime sized hail at times. I have updated PoPs for
the rest of the night. Current trajectory should take this
activity to the NE overnight with an overall weakening trend. Rest
of forecast looks on track. Hot and mainly dry. BT

&&

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

Longwave pattern consists of a trof along the Pac coast and flat
ridging over the northern high plains. East sfc flow and warming
mid levels have capped our airmass today, but a storm has
developed closer to upper trof and to our NW near Lewistown, and
weak great basin energy is producing scattered weak activity in
western WY. Our high terrain will be most likely to see isolated
tstms thru the remainder of the afternoon. Great basin shortwave
could clip our southeast by early this evening, so isolated pops
warranted there. Also, onset of southeasterly low level jet and
associated moisture advection will help to produce isolated/
elevated storms across our lower elevations tonight. Latest high
res models suggest best potential for this skirting across our
north along mid level warm front, reaching MLS-BHK by 09-12z. RAP
shows capes in excess of 1000 j/kg at Baker by 5am, so a nocturnal
strong storm is possible if one develops. Again, mid level warming
is a concern here.

Continued mid level warming and lack of a trigger should keep our
east capped on Monday, despite capes on the order of 2000 j/kg and
strongly veered wind profiles. This is something to watch as the
airmass would be ripe for a severe storm if something were to
develop. Drier air will exist to our west with deep mixing
expected tomorrow. Weak shortwave in SW flow aloft could produce a
few high-based storms in our west late tomorrow afternoon and
evening.

Another shortwave in southwest flow aloft may produce another
round of isolated high-based storms in our west on Tuesday,
especially as we begin to tap into monsoonal moisture, though any
rainfall will be light and very spotty. None of the convection in
our west each of the next two days will be severe, but could
definitely produce gusty and erratic sfc winds.

Temps will soar into the 90s to near 100 degrees the next two
days as SW flow sets up ahead of stationary Pacific coast trof.
Tuesday will be the warmer day in our east as winds shift to a
drier westerly direction after SE winds dominate Monday.

Main concerns moving forward will revolve around fire weather as
the hot and dry pattern establishes itself.

JKL

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


Only minor changes to the extended forecast period. Overall upper
level flow becomes zonal at the top of the ridge by Thursday
night...with continued shortwave activity. More pronounced upper
level ridging takes hold for Saturday before another stronger
shortwave pushing into the region Sunday afternoon.

Upper level ridging shallows out throughout the
extended forecast period...as multiple ridge running shortwaves
cross the region. This should provide at least a chance for
isolated showers and thunder in the high terrain...with some
evening potential across the plains periodically through the
period. Shortwaves are generally pretty weak...and timing is
inconsistent...so narrowing down areas of impact and timing is
difficult. That said...most significant waves appear to be
Wednesday night...Friday...and Sunday thus far. Moisture
availability will be limited through the period

Above normal temps are expected through the period...with temps
around the century mark on Wednesday. Temps look a bit cooler
through Friday...but ridging saturday and stronger shortwave trof
Sunday will drive temps back to upper 90s and possibly back toward
the century mark. AAG

&&

.AVIATION...

Isolated thunderstorms will move across the area tonight. Storms
will contain MVFR/IFR conditions with small hail. A few storms
will occur over and near the mountains Mon. afternoon into Mon.
evening with MVFR/IFR conditions. Expect localized areas of
mountain obscuration on Monday. Arthur

&&

.PRELIMINARY POINT TEMP/POPS...

    Mon     Tue     Wed     Thu     Fri     Sat     Sun
-----------------------------------------------------------
BIL 059/097 064/099 063/099 062/093 061/092 061/095 061/095
    21/U    11/U    11/U    11/U    11/U    22/T    11/B
LVM 049/097 053/096 052/095 051/091 049/090 049/093 051/094
    12/T    12/T    21/U    11/U    12/T    22/T    22/T
HDN 056/098 060/100 060/101 059/094 058/092 058/097 058/096
    31/U    11/U    11/G    11/U    11/U    22/T    11/U
MLS 062/098 067/102 066/100 064/093 061/093 061/095 063/096
    21/U    11/G    11/U    11/U    12/T    22/T    11/B
4BQ 060/098 064/100 064/101 062/095 061/094 061/094 061/096
    31/U    11/U    11/G    11/U    11/U    22/T    22/T
BHK 058/093 064/098 063/098 061/092 058/090 058/091 059/092
    21/U    11/U    11/U    11/U    11/U    22/T    22/T
SHR 054/100 059/100 059/101 058/094 056/092 056/093 056/095
    21/U    11/U    11/G    11/U    11/U    22/T    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
weather.gov/billings


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