• Mesodiscussion 1434 for 2013

Mesodiscussion 1434




MESOSCALE DISCUSSION 1434
NWS STORM PREDICTION CENTER NORMAN OK
0108 PM CDT FRI JUL 19 2013

AREAS AFFECTED...NRN LWR MICHIGAN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 191808Z - 191945Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...IT IS NOT CERTAIN THAT A WATCH WILL BE NEEDED...BUT IT
DOES NOT APPEAR OUT OF THE QUESTION THAT CONVECTION COULD INCREASE
AND INTENSIFY SUFFICIENTLY TO WARRANT A WATCH.  TRENDS ARE BEING
MONITORED FOR THIS POSSIBILITY.

DISCUSSION...ANOTHER BAND OF STRONGER MID/UPPER FORCING FOR UPWARD
VERTICAL MOTION APPEARS TO BE AIDING CONVECTIVE DEVELOPMENT NEAR THE
SURFACE FRONT...AND PERHAPS A PRE-FRONTAL OUTFLOW BOUNDARY...NOW
ADVANCING SOUTH SOUTHEASTWARD INTO NORTHERN LAKE MICHIGAN.  WITHIN
THE NEXT HOUR OR TWO...THIS APPEARS LIKELY TO PROGRESS INTO NORTHERN
PORTIONS OF LOWER MICHIGAN...WHERE THE BOUNDARY LAYER APPEARS TO BE
DESTABILIZING ONCE AGAIN IN THE WAKE OF EARLIER CONVECTION.  GIVEN
STRONG DEEP LAYER SHEAR BENEATH 50-60 KT WESTERLY 500 MB FLOW ACROSS
THIS REGION...INSTABILITY PROBABLY WILL BE SUFFICIENT FOR FURTHER
CONVECTIVE GROWTH AND INTENSIFICATION.  ISOLATED SUPERCELLS WITH
PERHAPS SOME UPSCALE GROWTH INTO A SMALL ORGANIZED CONVECTIVE
CLUSTER MAY NOT BE OUT OF THE QUESTION DURING THE 19-23Z TIME FRAME.

..KERR/THOMPSON.. 07/19/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DTX...APX...GRR...

LAT...LON   45658480 45448309 44058256 43768538 44248639 45038621
            45658480