SPC just issued this MCD…
MESOSCALE DISCUSSION 1550
NWS STORM PREDICTION CENTER NORMAN OK
1002 AM CDT FRI JUL 20 2007
AREAS AFFECTED…NRN/CNTRL AL INTO NWRN/W-CNTRL GA
CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE
VALID 201502Z – 201630Z
POTENTIAL FOR DAMAGING WINDS AND SOME HAIL IS EXPECTED TO INCREASE
WITH ONGOING TSTM COMPLEX THIS MORNING INTO AFTERNOON. CONVECTIVE
TRENDS ARE BEING MONITORED FOR A WW ISSUANCE.
E-W ORIENTED CLUSTER OF STORMS /SMALL MCS/ IS SLOWLY INTENSIFYING
THIS MORNING OVER NRN AL IN ADVANCE OF MID-LEVEL VORTICITY MAXIMUM
DIGGING SEWD THROUGH MIDDLE TN. MODIFICATION OF 12Z BMX SOUNDING
FOR CURRENT SURFACE CONDITIONS WITHIN SYSTEM INFLOW REGION SUGGESTS
THAT AIR MASS IS ALREADY UNCAPPED WITH MLCAPES OF 1000-1500 J/KG.
ADDITIONAL HEATING/DESTABILIZATION OF DOWNSTREAM BOUNDARY LAYER
SHOULD PROMOTE FURTHER INTENSIFICATION OF ONGOING STORMS WITH
ADDITIONAL DEVELOPMENT POSSIBLE ALONG SYNOPTIC COLD FRONT AND/OR ANY
RESIDUAL OUTFLOW BOUNDARIES.
REGIONAL VWPS INDICATE THE PRESENCE OF MODESTLY STRONG NWLY FLOW IN
ASSOCIATION WITH ABOVEMENTIONED SHORT WAVE TROUGH WITH 30-35 KT OF
SPEED SHEAR THROUGH THE LOWEST 3-4 KM AGL. AS SUCH…POTENTIAL WILL
EXIST FOR SOME FORWARD PROPAGATION OF ONGOING SYSTEM WITH THE
PRIMARY SEVERE THREAT BEING LOCALLY DAMAGING WINDS.
DISCUSSION AREA WILL INCLUDED IN A CATEGORICAL SLIGHT RISK IN THE
UPCOMING 1630Z DAY ONE OUTLOOK.
..MEAD.. 07/20/2007
