Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 180915

Area Forecast Discussion
National Weather Service Billings MT
315 AM MDT Fri May 18 2018

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

The convection from last evening has dissipated over eastern
Montana. Showers will become more widespread this morning as
colder air continues to move south. The best precip amounts will
be in the north to northeast facing aspects where upslope will
dominate. The higher elevations above eight thousand feet still
look to pick up a couple of inches of new snow.

Temperatures will be much cooler today with the cold air
advection. Highs will only be in the low to mid 50s. Extreme
southeast Montana may see temperatures around 60 degrees as the
cold front will be a little later to arrive. With these warmer
temperatures cannot rule out a few isolated thunderstorms this
afternoon with a little more instability present.

Expecting the showers to start decreasing overnight from east to
west as the flow starts to weaken and the moisture wanes. However
there will be a little energy that lingers over the
Beartooth/Absaroka Mountains into the afternoon on Saturday. With
a little instability in the afternoon, an isolated thunderstorm is
possible. Temperatures should be a little warmer as heights begin
to build, however still below normal. Highs will be in the mid to
upper 50s. Reimer

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

Weak upper level ridging will bring drier conditions to our region
Sunday and Monday. With a trof over the far western CONUS and
diffluent southwesterly flow extending into south central MT, the
exception will be over our western mountains/foothills where
mainly diurnal showers/t-storms can be expected each of these
days. Our eastern cwa will be stable w/ easterly surface winds.

The potential for convection will begin to increase across our cwa
Tuesday as western low moves slowly eastward thru the Great
Basin. Greatest chance of showers/t-storms will be Wednesday and
Thursday as this low lifts slowly through our area in some
fashion. Models are reasonably consistent here especially
considering the existing blocky pattern. Have raised pops on these
days, and feel that some moderate to heavy rain is a possibility
given anomalously high pwats on the order of 0.75-1.00 inches...
perhaps a bit higher in our far east.

The blocking pattern is highly suggestive of persistently weak
wind shear (as shown by the GEFS plumes), so don`t see a
significant threat of severe weather despite the active weather
next week.

Temperatures through the extended period will remain above normal
with highs mostly in the 70s to lower 80s.




Widespread showers will bring MVFR/IFR and local LIFR flight
conditions across the region today and tonight. Mountains will
remain obscured. JKL



    Tdy Sat     Sun     Mon     Tue     Wed     Thu
BIL 054 042/057 041/071 048/079 054/078 055/074 053/076
    8/W 84/W    11/B    12/T    23/T    35/T    44/T
LVM 054 039/055 040/070 044/076 047/075 047/071 047/073
    9/W 85/W    33/T    24/T    34/T    35/T    45/T
HDN 056 043/060 042/073 048/080 052/080 053/078 053/078
    8/W 74/W    11/B    11/U    12/T    35/T    44/T
MLS 054 042/061 042/068 050/078 053/079 056/078 056/077
    6/W 51/B    00/U    00/U    02/T    23/T    43/T
4BQ 061 042/057 040/066 046/076 053/078 055/076 054/076
    6/T 73/W    10/B    00/U    12/T    24/T    44/T
BHK 056 040/059 038/065 044/073 049/077 053/076 053/075
    6/W 51/B    00/U    00/U    12/T    22/T    34/T
SHR 059 040/055 039/069 045/077 049/077 051/072 050/074
    8/T 85/W    11/B    12/T    23/T    35/T    44/T




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