Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 010256
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
856 PM MDT WED AUG 31 2016

.UPDATE...

Another warm night on tap for the area as warm air persists just
above the surface and there continues to be plenty of wind to keep
the lower atmosphere at least somewhat mixed. Still 91 degrees at
8pm in Billings. Scattered to broken cloud cover and additional
wildfire smoke will also work to limit radiational cooling. As a
result of these factors increased overnight lows closer to those
of last night with most areas in the 60s to even a few lower 70s
for tomorrow morning. Dropped mention of thunderstorms tonight and
replaced with isolated sprinkles. Any precipitation tonight will
probably produce wind gusts of 20 to 35 mph in and near it. As
mentioned above expect gusty southerly winds to persist tonight,
mainly over southeast and into eastern portions of south central
Montana. Chambers

&&

.SHORT TERM...valid for Thu and Fri...

Forecast still on track for another hot couple of days ahead. The
upper ridge in place over eastern Montana today will get nudged
into the Dakotas. This will maintain, if not increase, downslope
flow and continue to manufacture temperatures in the 90s. Cumulus
clouds were developing over the west with isolated showers and
thunderstorms west of Park county this afternoon. Shear was not
strong, but enough to warrant the possibility of the convection
pushing east off the higher terrain a little ways. Will confine
evening PoPs to the west as convection will move northeast and
should not be able to propagate into central zones.

For Thursday, the upper ridge moves into the eastern Dakotas.
This will open the door up for increasing mid level clouds and
shortwaves through western and central zones. Shortwaves progged
across the area were expected to be rather weak and low levels
should remain very dry with dewpoints only in the lower to mid
40s, so will keep PoPs low. Not as much wind expected over the
southeast zones on Thursday as the tightest surface pressure
gradient pushes east. 700mb winds increase some, but not a great
deal with only 20kts showing up Thursday afternoon over western
zones. Upon coordination with surrounding offices, have decided to
just go with a strongly worded fire weather forecast for Thursday
for the west as winds will likely be borderline for Red Flag.

The main weather event will take place Friday afternoon and
evening. Models have sped up the timing of the expected cold
front, at least the GFS has. Timing now puts it in the western
zones Friday afternoon, central zones late afternoon to early
evening, and eastern zones mid to late evening. Hot tempeatures
with low humidity values can be expected ahead of the front with
some increased mixing producing stronger wind ahead of it. The
strongest winds will take place with the frontal passage as a very
tight pressure gradient will produce some gusts of 45-45 mph as
the front moves through. These winds could be exacerbated by
showers and thunderstorms that form along and just behind the
boundary. This looks to be a classic Red Flag day, so have issued
a Fire Weather Watch for Friday afternoon and evening. TWH

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

Confidence continues to improve for the extended forecast
period...as overall pattern remains in good agreement throughout
the period. That said...the specifics of the individual waves
crossing the region through the cyclonic flow remain somewhat
uncertain. In general...expect to see cool and unsettled weather
through the extended forecast period. Temps will be well below
normal...with highs in the low to mid 60s on Sunday and Monday. A
gradual warming trend is expected thereafter...but only to mid 70s
by Wednesday

Southwest flow remains in control over the region
Saturday...ahead of the approaching amplified pacific trof. PWATS
are reasonably good...with continued improvement through the
day. Have continued with slight pops through the morning/early
afternoon...but trended pops upward for overnight...with a
stronger piece of energy rotating through the region. Upper trof
begins push east at this point...with a lobe of energy shifting
across the region through Monday night. This period looks like the
best potential for precip across the region...so continued to
trend pops upward. Expect to see mountain snows with this
system...as 700mb temps drop below 0C Sunday night. The broad
upper level trof remains in control over the region through the
remainder of the period. Unstable cyclonic flow and continuous
progression of shortwaves continues through the period...so have
kept climo type pops in place through the remainder of the period.
AAG

&&

.AVIATION...

VFR will prevail across the area through the overnight. Gusty
southeast winds at the surface, strongest across the east, will
gradually decrease overnight. A few light showers are possible
tonight generally west of KBIL. Some gusty winds are possible with
the showers. LLWS can be expected near KMLS, KSHR, KBIL, and KBHK
mainly after 03z Thu. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 068/092 063/090 054/074 051/064 046/063 044/070 047/073
    12/T    22/T    22/W    34/T    55/T    42/W    22/W
LVM 062/091 053/083 044/072 041/062 038/061 037/069 040/070
    23/T    32/T    22/W    33/T    55/T    42/W    22/W
HDN 067/096 059/094 053/076 050/067 043/067 040/072 045/075
    12/T    21/U    22/W    34/T    66/T    42/W    22/W
MLS 069/097 065/095 057/077 053/068 047/066 046/070 049/075
    01/B    21/B    22/W    34/T    66/T    53/T    22/T
4BQ 065/094 063/095 056/076 052/068 045/067 045/070 047/075
    01/U    22/T    22/W    44/T    55/T    53/T    22/T
BHK 064/090 062/094 055/076 050/069 044/064 044/068 045/073
    01/N    22/T    22/W    44/T    55/T    53/T    22/T
SHR 064/095 057/091 051/075 048/067 042/066 041/069 043/073
    02/T    21/B    22/W    44/T    44/T    42/W    22/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Fire Weather Watch in effect from Friday afternoon through
      Friday evening FOR ZONES 123>133.
WY...Fire Weather Watch in effect from Friday afternoon through
      Friday evening FOR ZONES 274-284.

&&

$$
weather.gov/billings


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