Environment and Radar

   A warm front that actually more of a dew point boundary, was moving northward on late afternoon May 19th into the early evening bringing humid air northward across central and western Illinois.  Combined with temperatures in the mid 80s to low 90s, this air mass had strong instability. 

   As winds increased in the upper levels of the atmosphere across Missouri, eastern Iowa, and northwest Illinois, this leading edge of unstable air was able to be triggered with thunderstorms developing rapidly late in the day Sunday.  These storms would evolve north to northeast, in particular one complex which had more organization.  This developed a rain-cooled pool of air that produced a quicker forward motion and associated strong gusty winds. 

Storm Reports

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1052 PM CDT SUN MAY 19 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0805 PM     TSTM WND GST     5 NW POLO               42.04N 89.65W
05/19/2013  E50.00 MPH       OGLE               IL   CO-OP OBSERVER

            ESTIMATED 40 TO 50 MPH WIND GUSTS ON LEADING EDGE OF
            THUNDERSTORMS. SMALL TREE BRANCHES DOWN.

0820 PM     TSTM WND GST     FRANKLIN GROVE          41.84N 89.30W
05/19/2013  E60.00 MPH       LEE                IL   BROADCAST MEDIA

            ESTIMATED GUST TO 60 MPH. SEVERE DUST STORM REPORTED WITH
            NEAR ZERO VISIBILITY.

0844 PM     TSTM WND GST     2 N WINNEBAGO           42.30N 89.24W
05/19/2013  E45.00 MPH       WINNEBAGO          IL   BROADCAST MEDIA

            ESTIMATED GUST TO 45 MPH AT WREX WITH A DECENT DUST
            STORM.

0847 PM     HAIL             PECATONICA              42.31N 89.36W
05/19/2013  E1.75 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            GOLFBALL SIZE HAIL NEAR TRASK BRIDGE AND EDDY ROADS.

0852 PM     HAIL             N ROCKFORD              42.27N 89.06W
05/19/2013  E0.25 INCH       WINNEBAGO          IL   EMERGENCY MNGR

            PEA SIZE HAIL NEAR LATHAM AND ROCKTON AVE ON THE NORTH
            SIDE OF ROCKFORD.

0856 PM     HAIL             ROCKFORD                42.27N 89.06W
05/19/2013  E0.75 INCH       WINNEBAGO          IL   AMATEUR RADIO

            DIME SIZE HAIL ON CHARLES STREET.

0857 PM     HAIL             ROCKFORD                42.27N 89.06W
05/19/2013  E0.75 INCH       WINNEBAGO          IL   BROADCAST MEDIA

            DIME SIZE HAIL IN DOWNTOWN ROCKFORD.

0858 PM     HAIL             ROCKFORD                42.27N 89.06W
05/19/2013  E1.00 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            QUARTER SIZE HAIL NEAR GILFORD AND ALPINE.

0858 PM     TSTM WND GST     ROCKFORD                42.27N 89.06W
05/19/2013  E50.00 MPH       WINNEBAGO          IL   TRAINED SPOTTER

            ESTIMATED GUST TO 50 MPH NEAR GILFORD AND ALPINE.

0858 PM     TSTM WND DMG     ROCKTON                 42.45N 89.07W
05/19/2013                   WINNEBAGO          IL   PUBLIC

            POWER LINES DOWN AND POLES LEANING. SHREDDED BRANCHES
            EVERYWHERE NEAR HONONEGAH ROAD. RELAYED FROM WREX.

0859 PM     HAIL             ROCKFORD                42.27N 89.06W
05/19/2013  E1.25 INCH       WINNEBAGO          IL   TRAINED SPOTTER

            QUARTER TO HALF DOLLAR SIZE HAIL 2 MILES WEST OF
            DOWNTOWN. TIME ESTIMATED.

0905 PM     HAIL             ROCKFORD                42.27N 89.06W
05/19/2013  E0.25 INCH       WINNEBAGO          IL   AMATEUR RADIO

            PEA SIZE HAIL NEAR LINDEN AND 35TH STREET.

0913 PM     TSTM WND DMG     10 SE DURAND            42.33N 89.19W
05/19/2013                   WINNEBAGO          IL   AMATEUR RADIO

            EIGHT INCH TREE BRANCHES ON ROUTE 75, ONE MILE EAST OF
            MERRIDIAN ROAD.

0913 PM     HAIL             BELVIDERE               42.25N 88.85W
05/19/2013  E0.25 INCH       BOONE              IL   EMERGENCY MNGR

            ESTIMATED PEA SIZED HAIL AT BEAVER ROAD AND BEAVER
            SPRING.

0913 PM     TSTM WND DMG     10 SE DURAND            42.33N 89.19W
05/19/2013                   WINNEBAGO          IL   AMATEUR RADIO

            ESTIMATED 25 TO 30 INCH DIAMETER TREE DOWN ON ROUTE 75,
            APPROXIMATELY 1.5 MILES EAST OF MERRIDIAN ROAD.

0916 PM     HAIL             BELVIDERE               42.25N 88.85W
05/19/2013  E0.25 INCH       BOONE              IL   TRAINED SPOTTER

0917 PM     TSTM WND DMG     LOVES PARK              42.34N 89.01W
05/19/2013                   WINNEBAGO          IL   BROADCAST MEDIA

            TREES DOWN.

0919 PM     HAIL             BELVIDERE               42.25N 88.85W
05/19/2013  E0.88 INCH       BOONE              IL   EMERGENCY MNGR

            NICKEL SIZE HAIL NEAR VIESTA AND JULIAN ROADS.

0925 PM     HAIL             POPLAR GROVE            42.37N 88.82W
05/19/2013  E0.88 INCH       BOONE              IL   TRAINED SPOTTER

            NICKEL SIZE HAIL AT POPULAR GROVE AIRPORT.


&&

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AKREIN