A very unstable air mass was in place over Iowa with surface dew points in the upper 70s to low 80s following a day with highs in the 90s.  Lifted indices were in the -10 to -15 C. range as the low level jet began to strengthen during the nighttime hours.  A cold front to the northwest of the state began to sink southeast into Iowa as weak low pressure moved northeast along the front.  An MCS formed near the triple point of the low and the cold front, then tracked east across northern Iowa during the early morning hours.  Scattered thunderstorms formed south of the MCS, however most of them did not produce severe weather.  As the system evolved it took on a bow echo configuration as it raced across the state.  Numerous locations reported winds of 55 to 70 MPH along the path of the storm.  Trees were blown down in many locations.  There were no reports of widespread significant damage however.  The storms moved east of the state by sunrise.  One brief tornado touchdown was reported in a field just east of Mason City.  The tornado only touched the ground before lifting and caused no damage.  One person was injured as the storms moved through the area.  High winds toppled trees in the Clear Lake area.  One of the trees fell on a woman in a tent, pinning here and causing minor injuries.  She was taken to the hospital and received 11 stitches for a head injury.

Thunderstorm Wind in PALO ALTO, IOWA
From 03-JUL-03 23:37:00 to 03-JUL-03 23:37:00 (CST)
Location: RUTHVEN
Magnitude: 56 EG
Property damage: 5K
Reported by: UNKNOWN

Thunderstorm Wind in BREMER, IOWA
From 04-JUL-03 01:52:00 to 04-JUL-03 01:53:00 (CST)
Location: WAVERLY
Magnitude: 61 EG
Property damage: 5K
Reported by: UNKNOWN

Thunderstorm Wind in CERRO GORDO, IOWA
From 04-JUL-03 01:15:00 to 04-JUL-03 01:15:00 (CST)
Location: MASON CITY
Magnitude: 50 EG
Property damage: 3K
Reported by: UNKNOWN

Thunderstorm Wind in BUTLER, IOWA
From 04-JUL-03 01:37:00 to 04-JUL-03 01:37:00 (CST)
Location: DUMONT
Magnitude: 52 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in BREMER, IOWA
From 04-JUL-03 01:47:00 to 04-JUL-03 01:47:00 (CST)
Location: WAVERLY
Magnitude: 52 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in WINNEBAGO, IOWA
From 04-JUL-03 00:45:00 to 04-JUL-03 00:45:00 (CST)
Location: FOREST CITY
Magnitude: 52 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in EMMET, IOWA
From 04-JUL-03 00:10:00 to 04-JUL-03 00:10:00 (CST)
Location: RINGSTED
Magnitude: 52 EG
Property damage: 3K
Reported by: NEWSPAPER

Thunderstorm Wind in CASS, IOWA
From 04-JUL-03 01:00:00 to 04-JUL-03 01:00:00 (CST)
Location: MASSENA
Magnitude: 50 EG
Property damage: 2K
Reported by: FIRE DEPT/RESCUE SQUAD

Thunderstorm Wind in BUTLER, IOWA
From 04-JUL-03 01:34:00 to 04-JUL-03 01:34:00 (CST)
Location: CLARKSVILLE
Magnitude: 57 EG
Property damage: 5K
Reported by: UNKNOWN

Thunderstorm Wind in CERRO GORDO, IOWA
From 04-JUL-03 01:00:00 to 04-JUL-03 01:00:00 (CST)
Location: CLEAR LAKE
Magnitude: 52 EG
Property damage: 5K
Reported by: NEWSPAPER

Thunderstorm Wind in WINNEBAGO, IOWA
From 04-JUL-03 00:46:00 to 04-JUL-03 00:46:00 (CST)
Location: LAKE MILLS
Magnitude: 50 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in CASS, IOWA
From 04-JUL-03 01:05:00 to 04-JUL-03 01:05:00 (CST)
Location: MASSENA
Magnitude: 52 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in EMMET, IOWA
From 03-JUL-03 23:45:00 to 03-JUL-03 23:45:00 (CST)
Location: ESTHERVILLE
Magnitude: 52 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in EMMET, IOWA
From 03-JUL-03 23:52:00 to 03-JUL-03 23:52:00 (CST)
Location: ESTHERVILLE ARPT
Magnitude: 51 MG
Property damage: 1K
Reported by: AWOS,ASOS,MESONET,ETC

Thunderstorm Wind in KOSSUTH, IOWA
From 04-JUL-03 00:25:00 to 04-JUL-03 00:25:00 (CST)
Location: ALGONA
Magnitude: 52 EG
Property damage: 5K
Reported by: UNKNOWN

Thunderstorm Wind in WINNEBAGO, IOWA
From 04-JUL-03 00:30:00 to 04-JUL-03 00:30:00 (CST)
Location: FOREST CITY ARPT
Magnitude: 55 MG
Property damage: 10K
Reported by: NEWSPAPER

Thunderstorm Wind in WRIGHT, IOWA
From 04-JUL-03 00:50:00 to 04-JUL-03 00:50:00 (CST)
Location: BELMOND
Magnitude: 56 EG
Property damage: 15K
Reported by: UNKNOWN

Thunderstorm Wind in WINNEBAGO, IOWA
From 04-JUL-03 00:45:00 to 04-JUL-03 00:45:00 (CST)
Location: BUFFALO CENTER
Magnitude: 52 EG
Property damage: 5K
Reported by: NEWSPAPER

Thunderstorm Wind in BUTLER, IOWA
From 04-JUL-03 01:50:00 to 04-JUL-03 01:50:00 (CST)
Location: CLARKSVILLE
Magnitude: 53 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in BLACK HAWK, IOWA
From 04-JUL-03 01:54:00 to 04-JUL-03 01:54:00 (CST)
Location: WATERLOO
Magnitude: 50 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

Tornado in CERRO GORDO, IOWA
From 04-JUL-03 01:08:00 to 04-JUL-03 01:08:00 (CST)
Location: MASON CITY
Tornado F-scale: F0
Reported by: TRAINED SPOTTER

Brief tornado touchdown in field just east of Mason City.