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000
FXUS65 KBYZ 150951
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
351 AM MDT Mon Apr 15 2024

.DISCUSSION...

Today through Wednesday night...

Scattered rain showers, with a few weak thunderstorms, are
pushing north over western zones this morning as diffluent flow
moves over the region. This activity will continue to push north
into the morning hours, with a few rumbles of thunder possible.
While today will still be warm, northerly winds will keep
temperatures a bit cooler than yesterday, with highs in the 60s to
lower 70s. As we move into the afternoon and evening hours,
stronger forcing will move in across the area, along with
increased moisture (PWATs 0.5 to 0.9 inches, highest in far
southeast MT) and CAPE (500-800 J/kg, highest in far southeast
MT). With this, additional showers and thunderstorms look to
develop across the area. Over western and central zones, including
Billings, the thunderstorm potential remains limited. Any storms
that do form could still produce brief heavy rain, small hail, and
gusty winds. In southeastern MT, mainly Powder River and Carter
Counties, stronger thunderstorms are possible this evening. The
main threat will be heavy rain and small hail with any storm that
forms initially. The threat for stronger storms does not look to
be long lived though as more persistent moderate to heavy rain
looks to take over in this area through the overnight hours with
persistent surface convergence. At this time, forecast rain totals
are between 0.25 to 1 inch in Powder River and Carter Counties,
but locally higher amounts could be seen under stronger cells. By
Tuesday morning, this activity looks to gradually come to an end.

One thing to note with this first round of precipitation, snow
levels will be around 9000 ft before decreasing overnight. This
could create rain on snow, especially in the Bighorn Mountains.
At this time, there does not appear to be enough QPF to create a
problem, but this will be something to watch.

As the rain tappers off in the east Tuesday, our next system will
begin to drop in from the northwest. With this, precipitation
will increase over western areas Tuesday evening, increasing in
coverage overnight. While uncertainty remains on the end time of
the precipitation, precipitation looks to continue along the
foothills and mountains through Wednesday (70-90% chance) before
gradually tapering off late Wednesday into Thursday. At this time,
the majority of the precipitation with this second round looks to
fall along and south/west of a line from Harlowton to Billings to
Sheridan, with the highest amounts over the mountains and
foothills. As far as precipitation type goes, all snow is expected
in the mountains as snow levels quickly drop Tuesday night. Over
the lower elevations, including the foothills, rain is favored
Tuesday evening before transitioning over to snow Tuesday night
into Wednesday morning. This transition will be aided by the
colder air dropping in from the north. One thing to note, it will
be important to monitor the extend of the cold air moving in. If
it is a little colder than expected, higher wet snow totals could
be realized over the lower elevations, especially west of
Billings. Even Billings itself could see a wet inch of snow with
the cooler temperatures. As far as snowfall probabilities go, the
mountains have a 70-90% chance to see 10 or more inches of snow
and the foothills, including Red Lodge, have an 80% chance to see
6 or more inches of snow. Arends

Thursday through Sunday...

Snow will linger over the southern mountains and foothills on
Thursday, with cyclonic northwest flow remaining over the area and
upslope flow at the surface. Additional snow accumulations in the
mountains are expected to be light, generally a few inches or
less, with the foothills seeing an inch or less. Snow showers
remain possible (30-60% chance) over the southern mountains and
foothills on Friday. Shortwave ridging looks to build into the
region for Saturday, with ensembles split on what occurs Sunday
into early next week. Ridging and warmer conditions, or a Pacific
wave bringing more unsettled conditions.

High temperatures are forecast to range from the upper 30s to 40s
on Thursday and Friday, with 40s and lower 50s on Saturday.
Temperatures climb into the 50s and 60s for Sunday. Along with
high temperatures remaining below normal through much of the
extended, overnight lows will be in the 20s most nights as well.

STP

&&

.AVIATION...

In general, VFR will prevail through the period for most areas.
Showers and isolated thunderstorms will continue over western
areas through the morning, increasing over much of the area this
afternoon and evening. A few strong storms are possible over far
SE MT. Localized MVFR/IFR conditions are possible within areas of
heavy precipitation. Mountains will be obscured at times today and
tonight. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 070 046/064 035/044 026/045 026/044 026/049 030/062
    5/T 41/N    76/S    22/S    12/S    11/B    12/R
LVM 063 037/060 031/040 020/042 020/040 021/046 028/058
    7/T 33/R    87/S    22/S    12/S    11/B    12/R
HDN 071 046/066 035/046 025/048 024/045 024/050 029/065
    3/T 40/B    66/S    22/S    11/B    11/B    11/B
MLS 071 047/064 035/045 026/044 024/043 023/048 029/061
    2/R 51/N    12/S    11/N    00/B    01/B    01/B
4BQ 072 047/062 035/045 026/044 024/044 024/048 029/062
    3/T 72/R    13/S    11/N    01/B    11/B    01/B
BHK 071 043/060 032/045 023/041 020/039 020/045 025/057
    2/R 65/R    01/N    11/N    00/B    01/B    01/B
SHR 068 044/062 031/041 020/041 021/042 020/047 025/059
    4/T 61/N    68/S    43/S    22/S    22/S    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch in effect from Tuesday evening through
      Thursday morning FOR ZONES 56-66.
     Winter Storm Watch in effect from Tuesday evening through
      Thursday afternoon FOR ZONES 67-171.
WY...Winter Storm Watch in effect from Tuesday evening through
      Thursday afternoon FOR ZONE 198.

&&

$$
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