MD 1498 CONCERNING SEVERE POTENTIAL…SEVERE THUNDERSTORM WATCH LIKELY FOR PARTS OF EASTERN MT…SOUTHWESTERN ND…NORTHEASTERN WY…AND WESTERN SD
Mesoscale Discussion 1498
NWS Storm Prediction Center Norman OK
0204 PM CDT Tue Jul 11 2023
Areas affected...Parts of eastern MT...southwestern
ND...northeastern WY...and western SD
Concerning...Severe potential...Severe Thunderstorm Watch likely
Valid 111904Z - 112100Z
Probability of Watch Issuance...80 percent
SUMMARY...Storms capable of producing very large hail and severe
winds should spread eastward across the area this afternoon and
evening. A severe thunderstorm watch will likely be issued in the
next hour or two.
DISCUSSION...Latest visible satellite imagery shows gradually
deepening boundary-layer cumulus and isolated convective development
across parts of central into eastern MT this afternoon. Continued
diurnal heating/destabilization of a moist air mass (lower 60s
dewpoints) and DCVA preceding a shortwave trough over northwestern
MT should allow for additional thunderstorm development during the
next couple hours. 40-50 kt of midlevel westerly flow (per regional
VWP data) atop low-level southeasterlies will yield a long/straight
hodograph (45-55-kt effective shear) supportive of discrete
/semi-discrete splitting supercells. Very large hail up to 2.5
inches in diameter and locally severe winds will be possible with
these storms. With time, cell mergers and localized upscale growth
into several organized clusters will be possible, with a continued
risk of large hail and increasing damaging-wind threat. A severe
thunderstorm watch will likely be issued during the next hour or two
for parts of the area.
..Weinman/Mosier.. 07/11/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BIS...UNR...CYS...BYZ...GGW...RIW...
LAT...LON 44900659 45720724 46760745 47650750 48250740 48480716
48540677 48500623 48120520 47710431 47120352 46560292
46040248 45290195 44780169 44430156 44150148 43580150
43290177 43090219 43050302 43120344 43300390 43520438
43720478 43990531 44480609 44900659
