|Mesoscale Discussion 1277|
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Mesoscale Discussion 1277
NWS Storm Prediction Center Norman OK
0220 PM CDT Mon Jul 10 2017
Areas affected...Southwest and Central Montana
Concerning...Severe potential...Watch possible
Valid 101920Z - 102115Z
Probability of Watch Issuance...40 percent
SUMMARY...Thunderstorms producing locally strong winds and large
hail are possible across southwest and central Montana later this
afternoon and evening. A severe weather watch is possible in the
next 1-3 hours as thunderstorms organize over higher terrain in
advance of an upper level disturbance.
DISCUSSION...Thunderstorms continue to develop and organize ahead of
an upper-level shortwave which is lifting northeastward from Idaho.
The risk area is characterized by MUCAPE around 2000 J/kg with
effective deep-layer-shear of 35-45 kts, and steep low-level lapse
rates supporting damaging winds as storms organize and move
northeastward. Damaging winds are the primary threat in the
northern half of the area, with CAMS suggesting growth of a
low-level meso-high to further support damaging wind potential.
Storms characterized by mid-level rotation and an increased risk of
large hail will be more common along the southern periphery of any
organized wind producing system. Hail model estimates based on
RAP-based short-term forecasts suggest maximum hail sizes of 1.5
inches in diameter.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 44981368 45481397 45961390 46431337 46731263 47031140
47351030 47580943 47680878 47640807 47320759 47000728
46460701 45740705 45230801 45010893 44611064 44341181
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