747
FXUS65 KBYZ 121459
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
859 AM MDT Wed Jun 12 2024

.UPDATE...
Zonal flow exists over the region today, and early morning
convection has exited to our east. We will be left with post-
frontal breezy W-NW winds today, especially across our north/east,
but by midday there will be pressure falls to our southwest and
the resulting isallobaric wind will work against today`s mixed
wind potential. Otherwise, it will be sunny/dry with highs in the
upper 70s to mid 80s. Forecast has this covered well. JKL

&&

.DISCUSSION...

Today through Thursday night...

Satellite imagery showed zonal flow across our region with an
area of scattered showers and isolated thunderstorms across
eastern Montana thanks to some upper divergence and jet related
dynamics. These storms are expected to move into the Dakotas by
sunrise.

Westerly flow will rule today with downsloping flow keeping temps
above normal and drying out the lower levels. Wind gusts will be
highest along the western foothills with gusts 30-40 mph possible.
Elsewhere, look for west/northwest breeze 10-20 mph in the
afternoon in a well-mixed environment, with gusts generally in
the 20s (mph). Highs will be in the upper 70s to mid 80s. A weak
cold front drops in out of the north late tonight. No convection
is anticipated due to dry lower levels.

High pressure will rule on Thursday with dry conditions. Easterly
low level flow will prevail behind that aforementioned cold
front. This will mean somewhat cooler temps with readings mainly
upper 70s to lower 80s. BT

Friday through Wednesday...

Models were in better agreement for the system next week than
earlier runs. For Friday, upper ridge moves E of the area and SW
flow moves in behind it. A cold front will push E through much of
the area. It will be very warm...with windy conditions in KBHK
and Ekalaka. Most climate sites had a 50% chance of reaching 90
degrees, except KMLS and KSHR had an 80% chance. Deviated from NBM
PoPs, as deterministic models all had morning convection and NBM
only had PoPs in the far E. Added PoPs across the central and W
portions of the area based on CONSALL (20%). Bumped up PoPs in the
far E to 30% and had 30% in the SW mountains. For the afternoon,
there was an inverted trough in either the central or eastern part
of the area, so expanded low PoPs there. Also expanded PoPs post-
frontally. On the SREF, there was the potential for up to 2000
J/kg of MLCAPE E of KBIL starting in the afternoon. There was 40
kt of Bulk Effective Shear across the whole area. A low-level jet
will increase PWAT`s to 0.75-greater than 1 inch in the E through
Friday evening. Given the above, will be watching for possible
severe weather, mainly E of KBIL, Fri. afternoon and evening.
Storms will also contain heavy rainfall.

SW flow continues on Saturday and most Clusters showed the next
upper trough edging into MT on Sunday. Another cold front will
move into the area during Sat., bringing isolated to scattered
showers and thunderstorms in the afternoon and evening. Sunday
looked dry, but the trough will bring more precipitation Sun.
night. Temps will be in the 70s to 80s on Sat., but Sunday will be
cooler, in the 60s and 70s, as the trough will be anomalously
strong and cold. Western mountains will pick up a little snow Sun.
night.

For Monday through Wednesday, the trough will not move much as the
pattern across the CONUS will be an omega block. There were large
spreads in the QPF amounts for this period. PoPs will generally be
30-50%, but lower on Wednesday. NBM showed a 10-20% chance of an
inch of QPF for 12Z Mon. through 12Z Tuesday. Western mountains
will get some snow through the period, with at least several
inches over the Beartooth Pass. Note the NBM had a 10-20% chance
of at least a foot of snow over the highest elevations 00Z Mon.
through 00Z Wednesday. High temps will run in the 60s and 70s
through Wednesday. Will keep watching model trends to get finer
details with next week`s forecast. Arthur

&&

.AVIATION...

VFR will prevail across the region today and tonight, under a dry
westerly flow aloft. Mixed W-NW winds will be breezy today,
especially along the western foothills, and north/east of a
KBIL-K00F line. Expect 20-30kt gusts in these areas until 01z.
JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 085 052/081 057/089 057/084 050/071 048/069 050/069
    0/U 00/U    02/T    31/U    10/B    34/W    53/T
LVM 083 045/081 051/085 050/077 043/067 042/067 043/066
    0/N 00/U    05/T    32/T    11/B    45/T    54/T
HDN 085 050/083 057/090 057/088 050/074 048/072 050/071
    0/U 00/U    02/T    41/U    20/B    34/W    53/T
MLS 083 050/081 055/091 059/085 052/071 049/070 051/071
    0/U 00/U    02/T    41/U    30/U    44/W    63/W
4BQ 084 053/081 058/092 060/088 054/074 049/072 052/075
    0/U 00/U    02/T    31/U    20/U    43/W    52/W
BHK 083 047/079 051/086 057/085 051/073 045/070 048/073
    0/N 00/U    03/T    31/U    40/U    44/W    53/W
SHR 085 049/082 054/090 054/088 048/074 046/073 048/073
    0/U 10/U    02/T    21/U    10/U    33/T    52/T

&&

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

&&

$$
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