AREAS AFFECTED...PORTIONS SRN WI...NRN IL...CENTRAL/SRN
LM...CENTRAL/SRN LOWER MI.
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 301724Z - 301930Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...CONVECTION IS FCST TO INCREASE IN COVERAGE/INTENSITY
GRADUALLY THROUGH AT LEAST MID-AFTN...ALONG/AHEAD OF SFC COLD FRONT.
ASSOCIATED SVR POTENTIAL IS INCREASING AS FOREGOING/RICHLY MOIST
AIR MASS DESTABILIZES AND CINH WEAKENS. DAMAGING GUSTS AND LARGE
HAIL ARE EXPECTED FROM MOST INTENSE CELLS. INSTABILITY/CONVECTIVE
TRENDS WILL BE MONITORED FOR PSBL WW.
DISCUSSION...BKN BAND OF TSTMS IS MOVING SEWD ABOUT 30 KT ACROSS
PORTIONS E-CENTRAL/NERN LOWER MI. SVR POTENTIAL WITH THIS ACTIVITY
APPEARS MRGL AND CONFINED IN AREA...GIVEN RECENT TENDENCY FOR MORE
RAGGED REFLECTIVITY PRESENTATION AND WARMING IR CLOUD TOPS.
STILL...WITH MODIFIED RAOBS AND FCST SOUNDINGS SHOWING 500-1000 J/KG
MLCAPE AND 30-40 KT EFFECTIVE SHEAR OVER PARTS OF ERN LOWER MI ON
EITHER SIDE OF SAGINAW BAY...BRIEF FLARE-UP OF AN EMBEDDED CELL OR
TWO MAY YIELD ISOLATED DAMAGING GUSTS. OUTFLOW BOUNDARY FROM THIS
ACTIVITY EXTENDS FROM HTL AREA WNWWD ACROSS NWRN LOWER MI AND NRN LM
TO DOOR PENINSULA OF WI...AND SHOULD BE QUASISTATIONARY PRIOR TO
COLD FROPA. COLD FRONT WAS ANALYZED AT 17Z FROM ERN UPPER MI SWWD
NEAR GRB-VOK-CAV LINE. FRONT SHOULD CONTINUE MOVING SEWD ABOUT 15
KT. PREFRONTAL TROUGH/WIND-SHIFT WAS EVIDENT NEAR MTW-ALO
LINE...MOVING SEWD ROUGHLY APACE WITH COLD FRONT.
MORE SUSTAINED/CONCENTRATED SVR POTENTIAL IS EVIDENT FROM CENTRAL
LOWER MI WWD ACROSS LM INTO SRN WI...SHIFTING SEWD OVER SRN LOWER
MI...SRN LM AND NRN IL. VIS IMAGERY INDICATES CONVECTION
DEEPENING...INCLUDING A FEW YOUNG CB...ALONG WI/LM SEGMENT OF
PREFRONTAL TROUGH. LARGER LAPSE RATES ALOFT...RICH LOW-LEVEL
MOISTURE AND MORE SUSTAINED INSOLATION WILL LEAD TO FAVORABLE
DESTABILIZATION IN WARM SECTOR. SFC DEW POINTS COMMONLY IN 70S OVER
WI/IL/LM AND MID-UPPER 60S OVER LOWER MI WILL CONTRIBUTE TO MLCAPE
IN 2500-3500 J/KG OVER WI/IL AND 1500-3000 J/KG OVER REST OF
DISCUSSION AREA. RELATIVELY WEAK DEEP SHEAR WILL REMAIN ONE
LIMITING FACTOR FOR OVERALL ORGANIZATION...WITH EFFECTIVE SHEAR
MAGNITUDES REMAINING AOB 30 KT MOST AREAS.
..EDWARDS/GOSS.. 08/30/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DTX...APX...IWX...GRR...GRB...LOT...MKX...DVN...
ARX...
LAT...LON 42979075 43848861 44128587 44038441 44058299 44028280
43758263 43458254 43108248 42748251 42618254 42628281
42528286 42458380 42298533 42098776 42078941 42289010
42979075
