11/14/05 NOW: Southern Mississippi Valley

[Andy Wehrle]

Discrete storms firing in central and southern Arkansas with a severe warning for Grant County. With 0-6 km shear ranging from 45-50 kt and ~1,000 j/kg mlcape I could see some of these storms taking on supercellular characteristics, although the tornado threat seems conditional (SFC-1km shear 150 m2/s2) on a storm having its rotation enhanced by a boundary.

Note: Numbers from SPC mesoanalysis. I hope I read the maps correctly...

 

[nickgrillo]

Well, deep-layer shear is pretty poor invof previously SVR-warned storm -- and remains poor throughout the warm sector (with +45kts effective to the north of the warm front). Storms appear to be rather elevated (cluster near LZK) but given the deepening/moistening boundary layer -- with increasing surface temps -- some storms could become surface-based and could ingest unstable boundary layer parcels. However, as mentioned above, the poor vertical shear will result in only brief severe thunderstorms. Not really seeing the warranting of a red box... But given the marginal <100m2/s2 0-1km SRH in the warm sector, I wouldn't be surprised to see a brief tornado to come out of any storm that can sustain itself long enough to produce.

 

[nickgrillo]

Very nice isolated supercell in northeast MS ongoing at the moment... With some decent low-level rotation between Plantersville and Fulton. If the storm can sustain itself for a little while, I wouldn't be surprised if it produces a tornado (the atmosphere is favorable for a isolated, but rather short-lived supercells thanks to the poor vertical shear).

 

[Chris C Sanner]

Large Red-Box is now out for OK/MO/AR. The watch box looks like it cuts Norman in half where it lies. I'd expect storms to start becoming more numerous here in OK and probably some warm front nocturnal supercells. Hopefully people don't get caught offguard tonight