Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 271509

Area Forecast Discussion...Updated
National Weather Service Billings MT
909 AM MDT FRI MAY 27 2016

Forecast was in good shape this morning and made just some minor
adjustments. Stratus covered most of SE MT E of KBIL on visible
satellite imagery. Some clouds and showers noted coming into the
west. Models generated very light QPF over SE MT by 18z, but with
stratus in place, believe atmosphere will remain too stable to
support shower development. Otherwise, models were in good
agreement in generating showers and thunderstorms over the western
zones and bringing them E to KBIL by 00Z Saturday. Forcing will
not be overly strong so the slight chance of thunder seemed
justified. CAPES on the SREF were 500 j/kg at best and shear was
quite low. Precipitable waters will be a half inch to /0.75/
inches so some heavy rain with storms is possible especially if
storms converge around KBIL as suggested by the NSSL WRF. Low
freezing levels around 6000 ft AGL will support possible small
hail. Models carry the chances of convection through 06Z tonight.
Only changes to forecast were to update winds to a more easterly
component this afternoon and evening based on ADJLAV and to adjust
sky cover based on visible satellite and model trends. Arthur


.SHORT TERM...valid for Tdy and Sat...

Minor changes to the short term forecast this morning, with
models remaining in good agreement on disturbance dropping into
the region today and Saturday.

Although the strongest energy remaining to our west and northwest
across north central Montana today, a Pacific front will move into
the area this afternoon. This should bring increasing chances for
showers and thunderstorms across western areas. Raised pops across
western zones slightly, and extended slight pops a bit further
east for lingering showers this evening. The best area for
stronger thunderstorms appears to be around Billings by mid
afternoon, with small hail and erratic gusty winds, as cold pool
moving east combines with good pwats at peak heating, and likely
multiple outflow boundaries from earlier activity. Any stronger
activity should taper off quickly after sunset.

Zonal flow aloft develops over the region Saturday. Weak upper
level energy and vorticity will continue to stream across the
area, bringing continued potential for showers and isolated
thunderstorms, but with less coverage overall than recent days.
Eastern zones should see best chances with improved CAPES.

Afternoon highs Friday and Saturday will be around normal with
readings in the upper 60s to lower 70s. Gilstad

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

Models struggling with consistency for Monday-Tuesday storm
system. Latest Canadian and GFS models drop a stronger wrapped
up system from the Pacific NW through the area during this period, while
the ECMWF is faster bringing the energy across as an open wave and
keeps main area of dynamics well north of the area along the
Canadian border. Given the differences in the models have kept
chance pops going and will await better consistency before making
adjustments for this period. Models come to better agreement with
strengthening ridge of high pressure developing mid to late week
and continuing into next weekend. This will trend drier and
warmer heading through the end of the week. Chambers


A few areas of stratus/fog will continue E and N of KBIL this
morning with MVFR/local IFR conditions through 18z. Isolated
shower activity late this morning over western zones will evolve
into scattered thunderstorms by mid day, spreading into central
zones around Billings by 23z. Wind gusts to 35kts and small hail
will be possible with storms this afternoon/evening along with
brief heavy rainfall. Additional stratus and fog development are
possible tonight into Saturday morning. Arthur/Borsum/Chambers


    Tdy Sat     Sun     Mon     Tue     Wed     Thu
BIL 069 048/067 046/075 049/070 046/063 044/068 046/075
    6/T 63/T    21/B    25/T    34/T    42/W    11/B
LVM 063 041/063 039/071 043/065 041/060 039/068 042/075
    6/T 63/T    21/B    34/T    43/T    32/W    11/U
HDN 072 047/070 045/077 049/074 045/064 042/068 045/077
    3/T 53/T    20/B    24/T    34/T    43/W    11/B
MLS 071 051/072 049/078 053/074 050/065 046/067 047/077
    2/T 24/T    21/U    34/T    44/T    43/T    21/B
4BQ 071 046/071 045/077 049/075 046/066 043/067 043/077
    2/T 24/T    21/B    23/T    33/T    33/T    21/B
BHK 069 046/071 044/076 049/072 045/065 042/064 041/073
    2/T 16/T    31/B    25/T    44/T    43/T    21/B
SHR 069 043/068 042/075 045/072 043/063 040/067 042/075
    4/T 33/T    22/T    25/T    34/T    43/W    11/B




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