Mesoscale Discussion 1289
NWS Storm Prediction Center Norman OK
0604 PM CDT Sat Jun 14 2025
Areas affected...portions of central and eastern Montana
Concerning...Severe potential...Watch possible
Valid 142304Z - 150030Z
Probability of Watch Issuance...40 percent
SUMMARY...Large, perhaps significant, hail and severe gusts will be
the primary threats from convection developing across central and
eastern Montana. A watch may be needed.
DISCUSSION...Convection is beginning to develop along the high
terrain in south central Montana with moist upslope
(east-northeasterly) surface flow and underneath the southern
periphery of a west-southwesterly mid- and upper-level jet. This
configuration has resulted in seasonably strong deep layer shear
(generally 40-50 kts effective bulk shear) with straight hodographs
per mesoanalysis. These factors when combined with a low freezing
level suggest large hail, perhaps significant severe hail, as a
primary threat, at least early on. With time, storms may cluster
with merging cold pools, and this would transition to a severe gust
threat. However, boundary layer RH is relatively high, and overall
flow is not appreciably strong, so this may limit the gust potential
from these storms. Additionally, some lingering inhibition is
present across south-central Montana associated with cirrus across
the region. This may reduce the number of storms, which would delay
the storm clustering and prolong the hail threat into the evening.
..Supinie/Smith.. 06/14/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 46331056 47211033 47760928 47880783 47770664 47060537
46290513 45400537 45050617 45070764 45150908 45641021
46331056
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
Category: Watches, Warnings, Advisories, & Hazards