Hail and Damaging Winds in Montana, July 11, 2023

Area Forecast Discussion
National Weather Service Billings MT
159 PM MDT Tue Jul 11 2023

.DISCUSSION...

Through Thursday Night...

Overnight convection is finally moving east of the forecast area
with mostly clear conditions over the forecast area late this
morning. Expect convection to initiate between noon and 2pm in a
couple of places, SE Montana, Bighorn Mountains, and the
Musselshell River Valley. Todays convection will be more intense
than yesterday, but will also be more limited in coverage. Models
continue to show several good helicity tracks with convection
today meaning the storms will be spinning and thus capable of
large hail and damaging winds where they do form. Latest SPC
outlook has a Slight Risk covering a good portion of the area from
Rosebud county east and a Marginal Risk back toward Billings.
Based on latest model runs the threat for any storms in the
Billings area looks very slight. Best area for a strong to severe
storm looks to be along and east of a Miles City to Broadus line
through about 8pm this evening. Weak and nearly stationary cold
front is currently located just northwest of the forecast area
outlined by weak ongoing convection near Lewistown. This front
will be a focus for storm initiation, but looks to need some
convective cold pooling to really get moving today, will see if
enough convection gets going to push this feature. If it does get
that push expect more convection over the western periphery of the
SPC Outlook.

Convection should end/push east around sunset this evening with a
quiet overnight period.

Drier air pushes in from the northwest on Wednesday for a
significant decrease in convective activity. Can't rule out
isolated weak instability showers over the plains, but any
thunderstorms will be very isolated and confined to the higher
terrain.

Flow aloft becomes more northwesterly on Thursday which will bring
an increase in instability with falling heights aloft. Models
trending higher with convective potential Thursday afternoon and
evening which makes sense given that flow pattern. Latest 850
temperature forecast shows a significant convective cold pool
developing and moving through the forecast area Thursday afternoon
and evening with 5-7C temperature drops in the heat of the day,
indicating this convective activity. Currently have
low precipitation chances in to cover this, but would expect an
increase in chances in the models going forward.

Temperatures will be near seasonal levels for the short term, with
highs in the mid to upper 80s. Chambers

Friday through Tuesday...

As the low in central Canada moves off to the east, this will
allow for ridging to build into our area on Sunday. As a result,
warmer and dryer conditions will persist through most of the
period. Weak disturbances in the upper levels can not be ruled out
to bring isolated chances of precip. Best chances for precip look
to be Monday night as the ridge starts to break down and move
east. Chances for rain remain under 20% through the period, but
could increase for Monday night as confidence increases on timing.

High temperatures will be in the 80s Fri-Sat and 90s Sun-Tues. TS

&&

.AVIATION...

Areas out west toward KLVM could see wind gusts up to 30kts this
afternoon. Isolated showers and thunderstorms will begin
developing over eastern MT and northeast WY this afternoon,
exiting MT/WY by around 3Z. Gusty winds up to 40kts, hail, and
heavy rain are expected with these storms. MVFR/IFR conditions are
possible in areas of heavy rain. Most of the area can expect VFR
conditions through tomorrow. TS

&&

.PRELIMINARY POINT TEMP/POPS...

    Wed     Thu     Fri     Sat     Sun     Mon     Tue
-----------------------------------------------------------
BIL 058/086 058/084 058/084 058/083 059/088 060/092 063/090
    10/U    02/T    10/U    01/U    00/U    00/U    10/U
LVM 050/085 053/082 051/082 053/084 054/088 055/092 057/089
    00/U    02/T    00/U    01/U    00/U    01/U    10/U
HDN 057/087 056/086 056/084 056/084 056/088 058/093 062/093
    10/U    01/U    10/U    00/U    00/U    00/U    10/U
MLS 060/085 058/086 058/084 059/083 057/085 059/091 064/093
    11/U    12/T    21/U    00/U    00/U    10/U    21/U
4BQ 061/085 058/087 058/082 058/083 057/086 059/091 064/092
    21/U    12/T    21/U    00/U    00/U    10/U    10/U
BHK 058/081 056/085 055/081 056/080 054/082 054/085 059/089
    31/U    11/U    21/U    10/U    00/U    10/U    11/U
SHR 055/083 055/083 053/081 053/081 053/085 056/090 059/090
    10/U    02/T    11/U    01/U    00/U    10/U    10/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Severe Thunderstorm Watch 473 in effect until 9 PM MDT this
      evening FOR ZONES 30>33-36-37-58.
WY...None.

&&

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