Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 231652

Area Forecast Discussion...Updated
National Weather Service Billings MT
952 AM MST Thu Nov 23 2017

No significant updates to the forecast for today and tonight.
Threat of wind in the western gap locations and I-90/Hwy 191 until
front comes in this evening. Strong frontogenesis progged along
front aided by strong upper dynamics as jet drifts over area.
Looks like it may be a narrow band of precipitation dropping north
to south later tonight. Still looks like mostly rain at lower
elevations, and maybe some snow above 7000 ft. BT


.SHORT TERM...valid for Tdy and Fri...

Main concerns in the short term are the gusty winds. Pressure
falls ahead of approaching upper level short wave will continue
to increase the pressure gradient across the region through the
day. Strongest winds will continue to be in the gap areas of
Livingston and Nye. Forecast wind gusts closing in on 70 mph still
look on track with these strongest winds late this afternoon and
early evening just ahead of a pacific front. One other area of
concern will be the fairly common gusty winds topping the Bighorns
dropping into the Sheridan area. Think this is a possibility
several hours ahead of the front centered around midnight tonight.
While not handled well by guidance, have increased winds in this
area along the I-90 corridor. Windy conditions will be noted
elsewhere, but not as strong yet still gusty especially behind
the front and lingering into Friday.

A quick shot of precipitation looks likely just behind the front
late tonight. No cold air with this system, so most areas will
see rainfall with some snow in the higher elevations mainly above
7k feet. System will quickly depart by early Friday morning.

Record high temperatures likely for most today as temperatures
climb well into the 60s with even some lower 70s possible. It
could be close to the record warmest Thanksgiving Holiday as well
getting close the warmth of Thanksgiving Day 1998 when high
temperatures peaked in the mid 60s to lower 70s. Thanksgiving
Holiday records can be found on a headline on our webpage. High
temperatures for Friday will be some 10 to 15 degrees cooler but
still well above normals. Frieders

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

Mainly dry conditions can be expected over the area for Saturday
and Sunday, before an upper low and associated trough are progged
to move into the Pac NW, putting the area under southwest flow.
Models indicate moisture and energy will advect into the region on
Monday as the trough moves through the intermountain west and a
Pacific cold front dives through the area. Precipitation chances
look to increase across the area Monday, with rain eventually
changing over to snow Monday night. Models then show precipitation
ending from west to east on Tuesday as the aforementioned system
moves east. The GFS is slightly quicker than the ECMWF with the
timing of this system. Differences exist in the models through the
remainder of the long term as the GFS wants to keep the area
mainly dry with ridging over the Northern Rockies, while the ECMWF
drops a clipper system through the area on Wednesday.

Periods of gusty to strong winds, highest along the western
foothills are possible through the long term, with the strongest
winds expected Sunday night into Monday ahead of the front, and
again Tuesday into Tuesday night. High temperatures in the 50s for
Saturday are expected to warm into the 60s for many places on
Sunday as downslope flow develops. Highs mainly in the 40s can
then be expected behind the cold front on Monday and through the
remainder of the long term. Low temperatures in the 20s and 30s
are possible. STP


Gusty SW surface winds with gusts in the 50 to 60 kt range will
occur in KLVM, with higher gusts possible just ahead of a cold
front around 06Z. Winds in the foothills will be gusty as well.
Strong wind gusts to 40 kt are possible ahead of the cold front at
KSHR after 06Z. Winds will remain gusty behind the front at KSHR
into early Friday. VFR will prevail over the area into Friday,
however brief MVFR in showers cannot be ruled out with the frontal
passage late tonight into Fri. morning. Mountain obscurations will
increase overnight and decrease from N to S Friday. Arthur



    Tdy Fri     Sat     Sun     Mon     Tue     Wed
BIL 067 038/054 031/052 037/063 037/047 030/043 028/045
    0/B 61/N    00/U    10/B    33/W    31/U    00/N
LVM 067 035/049 030/051 038/060 036/042 026/039 024/041
    0/N 82/W    01/N    11/N    44/W    31/N    00/N
HDN 068 038/056 028/054 034/065 036/049 027/043 025/046
    0/B 61/N    00/U    10/B    23/W    31/B    00/U
MLS 071 038/051 028/052 031/062 036/047 026/041 025/044
    1/B 30/N    00/U    10/B    23/W    31/B    00/U
4BQ 071 041/054 028/054 034/064 037/051 027/041 025/045
    1/B 41/N    00/U    00/B    23/W    32/J    00/U
BHK 068 038/050 026/051 029/062 034/046 023/037 022/042
    1/E 30/N    00/U    00/B    23/W    42/J    00/U
SHR 071 037/052 026/054 032/065 035/049 025/042 023/047
    1/E 44/W    00/U    00/B    24/W    41/B    00/U


MT...Wind Advisory in effect until 11 PM MST this evening FOR
      ZONES 65-66.


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