Damaging Winds in Ohio, July 21, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
208 PM EST SAT JUL 21 2001

ONGOING CONVECTION DUE TO SHORTWAVE IN GRT LKS WL SLOWLY EXIT THE
AREA TONIGHT. MAIN FCST PROB REMAINS POPS THOUGH AS ADDITIONAL
SHORTWAVES AND THEN A FRONT TO MOVE THROUGH THE AREA...

RUC HAD GOOD HANDLE ON SHORTWAVE AND WL USE IT FOR FIRST 6 HOURS.
VORT LOBE MOVING INTO DIFFLUENT FLOW AND AT 18Z WAS CENTERED OVER
SW LWR MI. AS THE ENERGY FROM THIS SYS PULLS TO THE SE AND THE LAKE
BREEZE SETTLES DOWN AFTER SUNSET...PRECIP CHCS SHUD DEC. NVA MVS IN
BEHIND FURTHER SUPPORTING DEC IN POPS TONIGHT.

AS THE RIDGE BREAKS DOWN A SERIES OF WEAK SHORTWAVES WILL MOVE
THROUGHT THE WESTERLIES. THE NEXT DISCERNABLE ONE OF CONCERN IS
TOMORROW NIGHT. ETA TAKES THE ENERGY FURTHER TO THE NORTH THAN AVN.
WITH THE H5 FLOW WNW...PREFER THE AVN SOLN HERE. MODEL CAPES 2500
J/KG WITH LI -7 SO WL CONTINUE WITH SCT POPS SUN AFTN. EVEN THO
THE ETA PULLS THE VORT TO THE NORTH IT BRINGS IN MORE SIG MEAN RH
JUST TO THE WEST. LATE SUN NIGHT THE MODELS DIFF EVEN MORE WITH THE
ETA INDICATING A S/W OVR MN/IA WITH NO SIG DYNAMICS OVR NRN IN...
WHILE THE AVN SHOWS WEAK PVA OVR NRN IN AND ANOTHER S/W FURTHER WEST
THAN THE ETA. WITH CONTINUED INSTABILITY AND POTENTIAL BOUNDARIES IN
THE AREA WILL KEEP CHC POPS ON SUN NIGHT AS WELL. ON TO F54 (MON) THE
AVN MVS A COMPLEX ACRS WI LEAVING FA IN SUBSIDENCE UNTIL F66 (MON
NIGHT) WHEN YET ANOTHER S/W BRINGS POTENTIAL FOR ANOTHER MCS. WL KEEP
CHC POPS ON MON NIGHT. ON TUE AS FRNT SAGS SOUTH IT WL TAKE PRECIP
CHCS WITH IT IN THE NRN FA ANYWAY.

POLAR LOW IN HUDSON BAY STILL EXPECTED TO DEEPEN AND ALLOW H5 WINDS
TO INCREASE AND HEIGHTS TO FALL BY WED AM. AVN HINTS AT TWO MORE
S/W...ONE IN SRN IA AND THE NEXT IN WRN KS RIPPLE THROUGH THE FLOW.
THESE S/W SKIRT THE SRN FA AND SO WL KEEP CHC POPS THERE ON WED
AND THUR. TEMPS TO BEGIN COOL DOWN MID WEEK AS FRNT MVS SOUTH OF
FA. WL GO DRY ON SAT AS NW FLOW IN DRIER CONDS PREVAILS.

TEMPS A LITTLE TRICKY TONIGHT GIVEN AREAS OF RAIN-COOLED AIR. EXPECT
SOME RETURN AS S/W EXITS AND SUN BREAKS OUT FOR A PD THIS AFTN. SO
WL CUT THE NRN ZONES JUST A FEW. WL BE HOT AND HUMID AS PER BOTH
MAV AND FWC TOMORROW. REST OF GUIDANCE TEMPS CLOSELY FOLLOWED.

.IWX...NONE.

ADOLPHSON