|Mesoscale Discussion 1111|
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Mesoscale Discussion 1111
NWS Storm Prediction Center Norman OK
0342 PM CDT Wed Jun 21 2017
Areas affected...Parts of southern Louisiana/Mississippi/Alabama and
the western Florida panhandle
Concerning...Tornado Watch 359...
Valid 212042Z - 212215Z
The severe weather threat for Tornado Watch 359 continues.
SUMMARY...Occasional low-topped supercell development with risk for
short-lived tornadoes will continue across north central Gulf
coastal areas into early evening.
DISCUSSION...The recent increase in vigorous cellular convective
development with embedded mesocyclones, near coastal
Mississippi/Alabama and the western Florida panhandle, appears to be
accompanying the approach of a low-level speed maximum (50+ kt at
850 mb). This has contributed to the enlargement of low-level
hodographs in the presence of peak boundary layer instability
near/inland of the coast. This enhancement of activity may persist
another couple of hours, before the perturbation shifts inland of
coastal areas areas, where persistent convective cloud cover and
precipitation is maintaining more stable boundary layer conditions.
Meanwhile, 2 mb 2-hour surface pressure falls are now noted near
southern Louisiana coastal areas, just ahead of the center of Cindy.
As the cyclonic circulation continues to slowly approach this area,
strengthening low-level flow and shear may contribute to increasing
favorable conditions for low-topped supercells with risk for
tornadoes across portions of south central and southeast Louisiana
coastal areas by 00-02Z.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 30239170 30069066 30078977 30428881 31068778 31048670
30388651 30078778 28968908 28818949 29029068 29309157
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