Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 211739
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
1139 AM MDT SAT MAY 21 2016

.UPDATE...
Will update to remove severe wording from Fallon and Carter
Counties where cap will be too strong to break through the
evening. Also will remove severe from areas W of KBIL due to thick
persistent cloud cover. Arthur

&&

.SHORT TERM...valid for Tdy and Sun...
Upper low over Oregon will finally start to shift northeast today
tracking into southern Alberta by tomorrow morning. Height falls
will induce broad scale lift across our region with progs also
indicating decent frontogenesis pushing from west to east across
our CWA. Ahead of this system southeasterly surface winds will
increase over southeast Montana keeping dewpoints relatively high
for this time of year in the upper 40s to mid 50s across our
eastern zones. Combined with good heating ahead of the frontal
push this will mean good mucape across our eastern zones along the
line of 2000 j/kg. Shear profiles will increase as well by evening
in the east as surface front is pushed through. We have been
talking about this for a few days...and now the stage looks set
for potential super cell development in our east. I have also
added a mention of strong storms with small hail and strong winds
across areas west/northwest of Billings earlier in the afternoon
due to good lift and frontogenesis.

Once all this activity pushes through our region we will be under
a drier air mass on Sunday. However, the general flow will be
cyclonic and unstable due to a broad scale trough over the
western CONUS. So we will continue to mention some garden variety
thunderstorms (more like thundershowers) for Sunday. Temperatures
will be 10 to 15 degrees cooler Sunday. BT

.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...
The weather next week continues to look unsettled. A chance of
showers and afternoon-evening thunderstorms exists each day as
numerous disturbances should move through the largely cyclonic
flow over the western U.S. There is some chance for more organized
rain from compact upper lows--one to our west and another to our
east--later in the week, as shown on the 00z ECMWF, but confidence
in this scenario is low given the long lead time and model
differences.

Temperatures should be near seasonal normals throughout the
period. RMS/BT
&&

.AVIATION...
Areas of MVFR to occasional IFR ceilings will continue through
18z west of a Roundup to Billings line. Isolated showers and
possibly a thunderstorm is also possible across this area this
morning. Further east very gusty southeast winds will continue
east of a Miles City to Broadus line with occasional gusts to
42kts in the KBHK vicinity through the day.

This afternoon will see convection increase with scattered showers
and thunderstorms. Convection will be most widespread west of
Billings and in a N-S line in the Rosebud county vicinity. A few
strong to possibly severe storms are possible with large hail the
main threat. MVFR to local IFR conditions in heavy rain can be
expected near any convection this afternoon into the late evening
hours. Chambers
&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 074 046/067 044/068 044/068 047/068 047/069 048/070
    3/T 32/T    22/T    23/T    33/T    33/T    33/T
LVM 063 039/058 039/060 038/062 040/064 040/065 040/066
    6/T 23/T    34/T    44/T    43/T    33/T    33/T
HDN 079 045/071 042/070 044/070 048/070 048/071 050/072
    2/T 32/T    22/T    22/T    23/T    33/T    33/T
MLS 086 052/073 047/072 047/071 050/071 050/071 050/072
    2/T 52/T    22/T    22/T    33/T    33/T    33/T
4BQ 085 049/072 042/071 044/071 048/069 047/069 048/071
    3/T 53/T    22/T    22/T    33/T    33/T    33/T
BHK 075 049/073 042/070 045/070 047/069 047/068 048/069
    2/T 53/T    22/T    12/T    33/T    33/T    33/T
SHR 079 042/067 038/066 041/066 043/065 043/066 044/066
    2/T 22/T    13/T    32/T    33/T    33/T    33/T

&&

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

&&

$$
weather.gov/billings



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