Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
ACUS11 KWNS 242147
SPC MCD 242146

Mesoscale Discussion 1670
NWS Storm Prediction Center Norman OK
0446 PM CDT Sun Sep 24 2017

Areas affected...Portions of Minnesota

Concerning...Severe potential...Watch unlikely

Valid 242146Z - 242345Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe hail and/or damaging wind reports are
possible late this afternoon into this evening. However, watch
issuance is not expected.

DISCUSSION...Widely scattered thunderstorms have developed this
afternoon near a cold front pushing east across Minnesota. Surface
heating ahead of the front and sufficient boundary-layer moisture
have promoted modest mixed-layer buoyancy (e.g., values generally
around 500-1000 J/kg), tempered by relatively poor mid-level lapse
rates. However, mid/upper southerlies around 40-50 kt are offering
adequate effective shear for occasional updraft organization, in
turn yielding a threat of isolated severe hail. Moreover, dry
mid-level air, well-mixed boundary-layer profiles, and
small-scale/localized bowing segments may foster a few stronger wind
gusts prior to substantive nocturnal cooling this evening. Despite
this wind/hail potential, a lack of more robust buoyancy is expected
to keep most storms below severe limits, likely precluding watch

..Picca/Guyer.. 09/24/2017

...Please see for graphic product...


LAT...LON   44129530 45829511 48119357 48249265 47719222 46449245
            43969393 43609459 43709509 44129530 is the U.S. government's official web portal to all federal, state and local government web resources and services.