A complex weather situation unfolded during the day on the 12th with a series of events coming together.  The forest fires in Colorado were a contributing factor to the thunderstorm initiation.  During the night of the 11th and early morning of the 12th, two mesoscale convective systems formed over the fires in Colorado and tracked across Kansas.  By sunrise on the 12th, the outflow from one of the complexes pushed north into northern Kansas and Southern Nebraska to interact with a quasi-stationary frontal boundary.  Thunderstorms developed in this area and began to track east along the frontal boundary.  The airmass near the front was quiet unstable with dew point temperatures in the low to mid 70s.  During the day, some clearing allowed for heating to take place.  Once surface temperatures reach 27 C. there the negative inhibition was gone and surface based thunderstorms began to form.  Meanwhile, a large and unseasonably strong upper low began to drop southeast into the north central U.S. and interacted with the developing storms.  Thunderstorms formed in two rounds.  The first round rolled across the state during the mid afternoon hours into the early evening.  Another cluster of storms formed in the wake of the first by mid evening.  For the most part, severe weather from the storms was in the form of hail.  There were numerous reports of nickle to quarter size hail.  Nearly all of the storms produced up to marble size hail.  High winds were reported with one of the storms in Taylor County.  The winds tore the roofs of of barns in the area south of Siam.  Wind damage was also reported southwest of Bedford with trees blown over.  Crops were damaged by hail in many areas.  Widespread crop damage occurred in Taylor County south of Siam due to the combination of winds and hail.  The storms produced very heavy rainfall in many areas.  Flash flooding took place in southern Polk County, especially in Des Moines and areas east and south.  Rainfall rates were in the 2 to 3 inch per hour range.  The city of Des Moines was hard hit with flooded streets.  There were numerous reports of stalled vehicles with water two to three feet deep in the streets.  East of Des Moines in the Runnells area, low lying gravel roads between Runnells and highway 163 were barricaded as they went under water.  Damage occurred to some of the county gravel roads as well as numerous houses by basement flooding.  Flash flooding also occurred in Dallas County.  Highway 44 was under several inches of water east of Dallas Center.  Flood waters were over Highway 141 west of Perry as well.

Hail in MADISON, IOWA
From 12-JUN-02 15:25:00 to 12-JUN-02 15:25:00 (CST)
Location: TRURO
Magnitude: 0.88 
Property damage: 3K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Hail in WARREN, IOWA
From 12-JUN-02 15:25:00 to 12-JUN-02 15:25:00 (CST)
Location: NEW VIRGINIA
Magnitude: 0.88 
Property damage: 3K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Hail in POLK, IOWA
From 12-JUN-02 15:55:00 to 12-JUN-02 15:55:00 (CST)
Location: PLEASANT HILL
Magnitude: 0.88 
Property damage: 5K
Crop damage: 2K
Reported by: LAW ENFORCEMENT

Hail in POLK, IOWA
From 12-JUN-02 16:19:00 to 12-JUN-02 16:19:00 (CST)
Location: PLEASANT HILL
Magnitude: 1.00 
Property damage: 5K
Crop damage: 2K
Reported by: LAW ENFORCEMENT

Hail in POLK, IOWA
From 12-JUN-02 16:25:00 to 12-JUN-02 16:25:00 (CST)
Location: ALTOONA
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: BROADCAST MEDIA

Flash Flood in POLK, IOWA
From 12-JUN-02 16:49:00 to 12-JUN-02 21:28:00 (CST)
Location: SOUTH PORTION
Property damage: 150K
Crop damage: 15K
Reported by: LAW ENFORCEMENT

Hail in POLK, IOWA
From 12-JUN-02 17:09:00 to 12-JUN-02 17:09:00 (CST)
Location: ANKENY
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: AMATEUR RADIO

Hail in POLK, IOWA
From 12-JUN-02 17:10:00 to 12-JUN-02 17:10:00 (CST)
Location: ANKENY
Magnitude: 1.00 
Property damage: 10K
Crop damage: 1K
Reported by: AMATEUR RADIO

Hail in POLK, IOWA
From 12-JUN-02 17:25:00 to 12-JUN-02 17:25:00 (CST)
Location: ELKHART
Magnitude: 0.88 
Property damage: 3K
Crop damage: 5K
Reported by: FIRE DEPT/RESCUE SQUAD

Thunderstorm Wind in TAYLOR, IOWA
From 12-JUN-02 18:30:00 to 12-JUN-02 18:30:00 (CST)
Location: BEDFORD
Magnitude: 56 E
Property damage: 5K
Reported by: LAW ENFORCEMENT

Hail in TAYLOR, IOWA
From 12-JUN-02 18:30:00 to 12-JUN-02 18:30:00 (CST)
Location: BEDFORD
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Hail in TAYLOR, IOWA
From 12-JUN-02 18:30:00 to 12-JUN-02 18:30:00 (CST)
Location: SIAM
Magnitude: 1.00 
Property damage: 10K
Crop damage: 20K
Reported by: EMERGENCY MANAGER

Thunderstorm Wind in TAYLOR, IOWA
From 12-JUN-02 18:30:00 to 12-JUN-02 18:30:00 (CST)
Location: SIAM
Magnitude: 56 E
Property damage: 30K
Reported by: EMERGENCY MANAGER

Hail in WAPELLO, IOWA
From 12-JUN-02 22:31:00 to 12-JUN-02 22:31:00 (CST)
Location: BLAKESBURG
Magnitude: 1.00 
Property damage: 5K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Flash Flood in DALLAS, IOWA
From 12-JUN-02 17:45:00 to 12-JUN-02 20:00:00 (CST)
Location: COUNTYWIDE
Property damage: 25K
Crop damage: 15K
Reported by: EMERGENCY MANAGER

Hail in MADISON, IOWA
From 12-JUN-02 22:00:00 to 12-JUN-02 22:00:00 (CST)
Location: ST CHARLES
Magnitude: 0.75 
Crop damage: 5K
Reported by: BROADCAST MEDIA

Thunderstorm Wind in MADISON, IOWA
From 12-JUN-02 22:00:00 to 12-JUN-02 22:00:00 (CST)
Location: ST CHARLES
Magnitude: 52 E
Property damage: 8K
Reported by: BROADCAST MEDIA

Hail in MONROE, IOWA
From 13-JUN-02 00:22:00 to 13-JUN-02 00:22:00 (CST)
Location: ALBIA
Magnitude: 0.75 
Crop damage: 5K
Reported by: BROADCAST MEDIA

Hail in MONROE, IOWA
From 13-JUN-02 00:30:00 to 13-JUN-02 00:30:00 (CST)
Location: ALBIA
Magnitude: 0.75 
Crop damage: 5K
Reported by: BROADCAST MEDIA