|Mesoscale Discussion 747|
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Mesoscale Discussion 0747
NWS Storm Prediction Center Norman OK
1139 AM CDT Wed May 17 2017
Areas affected...Northeast KS...Southeast NE...Northwest MO...IA
Concerning...Severe potential...Watch likely
Valid 171639Z - 171745Z
Probability of Watch Issuance...95 percent
SUMMARY...Severe thunderstorms are expected to develop ahead of a
migratory low in northeast KS, then spread into IA. Isolated
tornadoes are expected along with large hail and damaging winds.
DISCUSSION...Exit region of strong mid-level jet is rapidly
spreading across northeast KS late this morning. As 90kt+ 500mb
speed max translates into northwest MO by 18z large-scale forcing
for ascent will shift into IA. Mid-high level cloudiness has
cleared nicely ahead of this feature and strong boundary-layer
heating is observed ahead of the surface low. Diagnostic data
suggests surface-3km lapse rates are now in excess of 8 C/km across
northeast KS and further steepening is expected along a corridor
extending into IA as high clouds clear. Latest visible satellite
imagery suggests boundary-layer cu field is thickening immediately
ahead of surface drying from eastern KS, arcing toward southeast NE.
While deep convection is evolving along the trailing cold front,
latest thinking is discrete supercells will evolve ahead of the
front then track northeast into an increasingly buoyant air mass.
Isolated tornadoes are expected, along with hail and wind.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 39509544 40189680 42449456 41569197 39119382 39509544
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