Mesoscale Discussion 0173 NWS Storm Prediction Center Norman OK 0501 PM CDT Fri Mar 14 2025 Areas affected...eastern Nebraska...Iowa...southern Minnesota...southwestern Wisconsin...and northwestern Illinois Concerning...Severe Thunderstorm Watch 31... Valid 142201Z - 142330Z The severe weather threat for Severe Thunderstorm Watch 31 continues. SUMMARY...Thunderstorms are moving rapidly northward across Iowa, where risk for strong/damaging wind gusts amd severe-caliber hail will continue. New WW issuance will likely be required north of the existing watch, into southern Minnesota, and -- thereafter -- east of the watch into eastern Iowa/northwestern Illinois. DISCUSSION...Latest radar loop shows an arcing band of strong/severe storms extending eastward from eastern Nebraska into/across southwestern Iowa, and then southeastward and southward across Missouri. The west-to-east portion of the band is moving quickly northward/north-northwestward, while the more north-south portion across Missouri is advancing rapidly northward/north-northeastward. A second cluster of strong/rotating storms -- north of the west-to-east band -- is moving north-northwestward across west-central Iowa at this time. Greater low-level moisture (dewpoints in the 50s) exists across far southern Missouri and into Arkansas, and is spreading northward on strong southerly flow. However, a dry, deeply mixed boundary layer (to around 700mb) is evident from central and northeastern Missouri northward, with modest CAPE above the mixed layer. While severe-caliber hail remains possible locally -- particularly with the more isolated, west-central Iowa storms, the primary severe risk remains very strong/damaging wind gusts -- given both the intense, deep-layer wind field, and the sub-cloud dry air that will encourage evaporatively enhanced downdrafts. With the fast storm motion that is observed, severe risk will likely begin to spread north of the existing watch (into northern Iowa and eventually southern Minnesota) over the next hour or so. Meanwhile, storms moving quickly north-northeastward toward/into northeastern Missouri will also begin affecting adjacent southwestern Iowa/northwestern Illinois -- i.e. the DVN CWA -- starting in the next hour or so. New WW issuances will be considered in both of these surrounding areas. ..Goss.. 03/14/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...MPX...DMX... EAX...FSD...OAX...GID... LAT...LON 40109740 41189767 42649683 43669568 44099397 43939069 42518949 41388921 40178981 40109740
Source link