Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 291448
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
848 AM MDT Sat Apr 29 2017

.UPDATE...
Only concern this morning is fog. Satellite imagery and ground
truth suggest its most dense along the Yellowstone from near
Laurel to around Livingston. However its relatively patchy so will
not issue an advisory for it. We have enough sunshine at this time
that the fog should dissipate by around 10-1030 AM at most
locations.

Only other adjustments were to the PoP`s. Removed PoP`s this
morning due to stability in lower levels, and reduced them a bit
for the afternoon and evening as snow cover over high country may
limit instability and forcing appears pretty weak. BT

&&

.SHORT TERM...valid for Tdy and Sun...

Several minor changes to the short term forecast this morning. The
pattern remains unsettled, but will be warming up significantly
over past few days.

Patchy fog this morning will give way to clear skies by late
morning...allowing for temperatures to climb into the 50s in most
areas and a few 60s east. A weak trof axis will shift across
central Montana this evening. Best energy appears to stay north,
but with available sfc moisture and heating, even a weak
disturbance would be enough to trigger showers. Best chances will
be in high terrain, with orographic support, but have spread pops
across the plains the region this evening as well. Would not
expect activity to persist for long after sunset.

Temps will continue to trend upward for Sunday with highs in the
60s in most locations. More shortwave energy tracks out of Canada
and into Montana on Sunday...bringing mountain showers through
much of the day. A wet pacific cold front will slide through the
CWA Sunday evening and bring widespread rains showers across the
region through the night. AAG

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

Unstable northwest flow on Monday and Tuesday will result in
breezy/showery conditions with slightly below normal temps.
Tuesday looks like the wetter of the two days, especially for our
west/central parts, with enough instability to produce some
lightning. Lower elevation precip will be mainly in the form of
rain, with graupel/ice pellets possible given the low freezing
levels and instability. Mountains will pick up some snowfall,
potentially on the heavy side for the Bighorns Tuesday per the
favorable NW flow. Precipitation will taper off Tuesday night as
heights build from the west. Could see a few showers linger in our
far east into early Wednesday as PV finally exits.

Dry and warmer conditions in store Wednesday thru Friday as a
fairly strong ridge builds over the region. Expect temps back to
the 60s Wednesday and into the 70s Thursday. There continues to be
model issues regarding the break down of this ridge late in the
week. On a broader scale, evolution of the longwave pattern across
the CONUS is tricky with model uncertainties regarding trof
emerging from the north Pacific, and a deep low over the eastern
CONUS. The ECMWF and Canadian are in agreement showing an omega
block developing across the CONUS, with the GFS being more
progressive (and quicker to bring cooler air into our region). Not
sure how this will pan out into next weekend, but for now will
keep with a warm scenario through Friday, as suggested by the
ECMWF and most GEFS members that far out. Have adjusted Friday
temps up as this may be the warmest day of the week. Will
introduce a chance of showers in our west on Friday as well per
expectation of height falls by then. Should see a better chance of
precipitation by next weekend.

JKL

&&

.AVIATION...

Patchy valley fog will burn off through the late morning. Any fog
that develops could reduce flight conditions to MVFR or lower,
but confidence at any given TAF site is low at this time. VFR
will prevail across the region today and tonight. Isolated showers
are expected this afternoon and early evening, mainly west of
MLS-4BQ. Local/brief MVFR is possible in any showers, and
mountains will be occasionally obscured. JKL/Dobbs

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 056 037/063 041/058 040/055 038/065 044/074 048/073
    1/B 12/W    42/W    35/W    21/B    00/U    11/B
LVM 052 033/058 035/055 034/054 032/063 038/070 043/069
    2/W 13/W    42/W    44/W    21/B    00/U    12/W
HDN 057 033/065 041/059 039/057 037/065 039/073 045/075
    2/W 22/W    43/W    25/W    21/B    00/B    11/B
MLS 061 034/065 043/059 039/058 039/064 043/073 048/073
    1/B 01/B    33/W    22/W    21/B    00/B    10/U
4BQ 057 030/064 041/057 037/057 036/062 041/071 045/074
    0/B 01/U    34/W    23/W    22/W    00/B    00/U
BHK 060 030/062 038/056 035/055 034/060 036/068 042/071
    0/B 00/U    44/W    22/W    22/W    00/B    00/U
SHR 049 027/056 038/053 036/051 034/060 037/070 039/074
    1/B 11/B    53/W    25/W    31/B    00/U    01/U

&&

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

&&

$$
weather.gov/billings


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