Alert archive / Iowa / Heat Advisories in 2021

Heat Advisory 4, NWS Quad Cities, IA

August 8, 202121 counties in Iowa; 13 counties in Illinois; Clark County, Scotland County, Missouri

NWS Quad Cities, IA issued this heat advisory at Aug 8, 2021, 2:24 PM CDT for 21 counties in Iowa; 13 counties in Illinois; Clark County, Scotland County, Missouri. It took effect at Aug 9, 2021, 12:00 PM CDT. It was in force for 31 hr.

The area

The counties it named.

The facts

Issued
Aug 8, 2021, 2:24 PM CDT (19:24 UTC)
In effect from
Aug 9, 2021, 12:00 PM CDT
Expired
Aug 10, 2021, 7:00 PM CDT
In force
31 hr
Issued by
NWS Quad Cities, IA
All 36 counties

Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Bureau County, IL, Carroll County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, McDonough County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Clark County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 41 km from the middle of the area, began a volume at 19:24 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 7.4 hours before the alert went out and 47 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2021-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 567 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2021-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
567 J/kg
Mixed-layer CIN
-127 J/kg
Mixed-layer LCL
1067 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
-8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

964 
WWUS73 KDVN 081924
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
224 PM CDT Sun Aug 8 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-090330-
/O.NEW.KDVN.HT.Y.0004.210809T1700Z-210810T0100Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
224 PM CDT Sun Aug 8 2021

...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM CDT MONDAY...

* WHAT...Heat index values up to 104 expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...From noon to 8 PM CDT Monday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
Haase
www.weather.gov/dvn
9 follow-up statements
963 
WWUS73 KDVN 090209
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
909 PM CDT Sun Aug 8 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-091015-
/O.CON.KDVN.HT.Y.0004.210809T1700Z-210810T0100Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
909 PM CDT Sun Aug 8 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TO 8 PM CDT MONDAY...

* WHAT...Heat index values up to 104 expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...From noon to 8 PM CDT Monday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

www.weather.gov/dvn
023 
WWUS73 KDVN 091133
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
633 AM CDT Mon Aug 9 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-091945-
/O.EXT.KDVN.HT.Y.0004.210809T1700Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
633 AM CDT Mon Aug 9 2021

...HEAT ADVISORY NOW IN EFFECT FROM NOON TODAY TO 7 PM CDT
TUESDAY...

* WHAT...Heat index values up to 106 expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...From noon today to 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

www.weather.gov/dvn
899 
WWUS73 KDVN 091525
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
1025 AM CDT Mon Aug 9 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-092330-
/O.CON.KDVN.HT.Y.0004.210809T1700Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
1025 AM CDT Mon Aug 9 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT TUESDAY...

* WHAT...Heat index values up to 106 expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...From noon today to 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
Haase
www.weather.gov/dvn
626 
WWUS73 KDVN 091844
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
144 PM CDT Mon Aug 9 2021

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-100245-
/O.EXB.KDVN.HT.Y.0004.210810T1700Z-210811T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
144 PM CDT Mon Aug 9 2021

...HEAT ADVISORY IN EFFECT FROM NOON TO 7 PM CDT TUESDAY...

* WHAT...Heat index values up to 106 expected.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois.

* WHEN...From noon to 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-100245-
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
144 PM CDT Mon Aug 9 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT TUESDAY...

* WHAT...Heat index values up to 106 expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...Through 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
Haase
www.weather.gov/dvn
244 
WWUS73 KDVN 100124
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
824 PM CDT Mon Aug 9 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-100930-
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
824 PM CDT Mon Aug 9 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT TUESDAY...

* WHAT...Heat index values up to 108.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...Until 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-100930-
/O.CON.KDVN.HT.Y.0004.210810T1700Z-210811T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
824 PM CDT Mon Aug 9 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TO 7 PM CDT
TUESDAY...

* WHAT...Heat index values up to 106 expected.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois.

* WHEN...From noon to 7 PM CDT Tuesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

www.weather.gov/dvn
257 
WWUS73 KDVN 100815
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
315 AM CDT Tue Aug 10 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-101615-
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
315 AM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heat index values 100 to 107.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...Until 7 PM CDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-101615-
/O.CON.KDVN.HT.Y.0004.210810T1700Z-210811T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
315 AM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 7 PM CDT
THIS EVENING...

* WHAT...Heat index values of 100 to 106 expected.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois.

* WHEN...From noon today to 7 PM CDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

www.weather.gov/dvn
557 
WWUS73 KDVN 101519
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
1019 AM CDT Tue Aug 10 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-102330-
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
1019 AM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heat index values 100 to 110.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois. 

* WHEN...Until 7 PM CDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-102330-
/O.CON.KDVN.HT.Y.0004.210810T1700Z-210811T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
1019 AM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heat index values of 100 to 110 expected.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois. 

* WHEN...From noon today to 7 PM CDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
555 
WWUS73 KDVN 101928
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
228 PM CDT Tue Aug 10 2021

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-110330-
/O.NEW.KDVN.HT.Y.0005.210811T1700Z-210812T0000Z/
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
228 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING...
...HEAT ADVISORY IN EFFECT FROM NOON TO 7 PM CDT WEDNESDAY...

* WHAT...For the first Heat Advisory, heat index values up to 110.
  For the second Heat Advisory, heat index values up to 105 
  expected.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois.

* WHEN...For the first Heat Advisory, until 7 PM CDT this 
  evening. For the second Heat Advisory, from noon to 7 PM CDT 
  Wednesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-110330-
/O.NEW.KDVN.HT.Y.0005.210811T1700Z-210812T0000Z/
/O.CON.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
228 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING...
...HEAT ADVISORY IN EFFECT FROM NOON TO 7 PM CDT WEDNESDAY...

* WHAT...For the first Heat Advisory, heat index values up to 
  109. For the second Heat Advisory, heat index values up to 107 
  expected.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...For the first Heat Advisory, until 7 PM CDT this 
  evening. For the second Heat Advisory, from noon to 7 PM CDT 
  Wednesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
Haase
www.weather.gov/dvn
055 
WWUS73 KDVN 102352
NPWDVN

URGENT - WEATHER MESSAGE
National Weather Service Quad Cities IA IL
652 PM CDT Tue Aug 10 2021

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-110800-
/O.EXP.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
/O.CON.KDVN.HT.Y.0005.210811T1700Z-210812T0000Z/
Keokuk-Washington-Louisa-Jefferson-Henry IA-Des Moines-Van Buren-
Lee-Mercer-Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Sigourney, Washington, Wapello, 
Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, 
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
652 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TO 7 PM CDT
WEDNESDAY...
...HEAT ADVISORY WILL EXPIRE AT 7 PM CDT THIS EVENING...

* WHAT...Heat index values up to 107 expected Wednesday afternoon.

* WHERE...Portions of northeast Missouri, southeast Iowa and 
  northwest and west central Illinois.

* WHEN...Heat Advisory from noon to 7 PM CDT Wednesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

IAZ040>042-051>054-063>068-ILZ001-002-007-009-015>018-110800-
/O.EXP.KDVN.HT.Y.0004.000000T0000Z-210811T0000Z/
/O.CON.KDVN.HT.Y.0005.210811T1700Z-210812T0000Z/
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-
Including the cities of Independence, Manchester, Dubuque, 
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City, 
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Galena, 
Freeport, Mount Carroll, Sterling, Moline, Rock Island, Geneseo, 
Princeton, and Hennepin
652 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TO 7 PM CDT
WEDNESDAY...
...HEAT ADVISORY WILL EXPIRE AT 7 PM CDT THIS EVENING...

* WHAT...Heat index values up to 105 expected Wednesday afternoon.

* WHERE...Portions of east central and northeast Iowa and north 
  central and northwest Illinois.

* WHEN...Heat Advisory from noon to 7 PM CDT Wednesday.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$
Haase
www.weather.gov/dvn

What forecasters said that day

The local office's own words before this heat advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Quad Cities, IA wrote its last area forecast discussion before this heat advisory went out at Aug 8, 12:47 PM CDT, 1 hour 37 minutes earlier.

Area forecast discussion, Aug 8, 12:47 PM CDT, 1 hour 37 minutes before
Area Forecast Discussion
National Weather Service Quad Cities IA IL
1247 PM CDT Sun Aug 8 2021

...AVIATION UPDATE...

.UPDATE...
Issued at 435 AM CDT Sun Aug 8 2021

Showers and thunderstorms have rapidly fallen apart and lifted
northeast into MN and WI over the past hour, leaving only a few
elevated showers behind a fast moving outflow boundary moving
eastward across eastern Iowa. Mesoscale analysis suggests the mid
level moisture transport has waned and mid level lapse rates
diminished over the past hour, possibly due to influence of the
upstream, now dissipated, MCS that was over NW MO and eastern KS.

Chances for early morning showers and thunderstorms have thus
significantly diminished and POPs have been scaled back in the
latest forecast update. Further adjustments for lower POPS may be
needed depending on trends over the next couple hours. It is
possible that the next round of showers and thunderstorms may
hold off until mid to late afternoon, as suggested by the latest
HRRR and NAM model runs.

&&

.SYNOPSIS...
Issued at 320 AM CDT Sun Aug 8 2021

A large complex of thunderstorms associated with an upper level
shortwave over SE Nebraska reached from central IA across northwest
MO into eastern KS at 2 am. The main MCV was apparent over SE
Nebraska on radar mosaic, while a more subtle vortex was evident
lifting northeast over western IA. A wing of strong thunderstorms
with heavy rainfall and some small hail, fed by a low level jet
feed with PW values over 1.8 reached eastward from this feature to
just northwest of Vinton. Isolated, much weaker storms continued
to meander over far northwest Illinois, feeding on the elevated
warm air advection. An outflow boundary, remnant from when the
MCS was much stronger earlier this evening, was triggering
additional storms as it pushed eastward across south central Iowa.
Ahead of this system, it was a very warm and humid night over the
local area with temperatures in the mid to upper 70s and
dewpoints in the lower to mid 70s.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 320 AM CDT Sun Aug 8 2021

The primary focus is the potential for severe storms through
tonight. Otherwise, warm and humid conditions will continue
through tonight.

Early this morning, scattered showers and thunderstorms will likely
be ongoing over northeast Missouri and southeast Iowa with the
advancing outflow boundary. Elsewhere, coverage will likely be much
lower and more isolated as weak lift and cloud cover from the
convective system moves through the area through mid morning.

Forecast confidence is then low with convective trends that follow
from late morning through early afternoon. The next organized
round of thunderstorms looks likely to develop in the afternoon as
lift, steeper mid level lapse rates and 40 to 50 kt mid level
winds with the approaching shortwave interact with rebounding
instability. The latest deterministic models and convective
allowing models generally show this coming together over southeast
Iowa, northeast Missouri into west central Illinois in the mid
afternoon into evening hours. These could potentially be severe
with damaging wind the primary threat and large hail secondary.
The latest SPC day one outlook has a slight risk over much of the
forecast area for this possibility. Will also have a risk for
heavy rainfall rates that may need to be watched with slow moving
storms. Tonight, the potential for severe storms will wane, but
there could be lingering storms in the evening, then additional
late night redevelopment as the shortwave and embedded upper level
vort maxima rotate through area.

With the likelihood for extensive cloud cover, have kept highs lower
that yesterday, in the lower to mid 80s, However lingering
dewpoints in the 70s will keep conditions rather humid.

.LONG TERM...(Monday through Saturday)
ISSUED AT 320 AM CDT Sun Aug 8 2021

Key Messages:

1. Hot and humid through Thursday then near normal temperatures
expected through the weekend.

2. There are periodic chances of showers and thunderstorms through
Thursday night.

The long term period begins Monday morning with a west to east flow
across the CONUS. A shortwave trough slowly exits to the east of the
area and weak ridging builds across the Midwest ahead of another
shortwave trough that swing across the area on Tuesday. 500 mb
heights rise through the day on Monday but models show vorticity
maxima cutting through the ridge. Increasing instability especially
south of Interstate 80 along with 850 mb theta-e advection suggest
isolated to scattered showers and thunderstorms are possible Monday
afternoon and evening. . The wind field aloft remains weak with 0 to
6 km shear around 25 knots and the potential for surface based CAPE
of 3 to 4 thousand J/KG. For these reasons, the storm prediction
center as the area in a marginal risk for severe storms with large
hail and damaging wind gusts the main threats. Heavy rain is also a
concern as precipitable water beings to rebound up to 1.75 inches.

High temperatures on Monday have been lowered slightly due to
expected cloud cover across the region resulting in high
temperatures in the mid to upper 80s across the area. When combined
with lower to mid 70s dewpoints is producing heat indices in the mid
to upper 90s. The exception is southwest of a Fairfield to Keokuk
line where forecast heat indices range from 100 to 105. We will
continue to monitor this for potential heat advisory as the cloud
cover and dewpoints will play a role in the heat indices on Monday
afternoon.

Moisture and warm air advection ahead of the shortwave that will
move across the area Tuesday into Wednesday morning will help build
instability across the area along with some increasing wind shear.
Models have delayed precipitation slightly more towards overnight
than previous runs and also with the better lift across southern
portions of the area. The storm prediction center has another
marginal risk across the area for Tuesday into Tuesday night.
Tuesday will be the warmest day of the week due to sunny skies early
in the day with high temperatures climbing into the lower 90s. Model
dewpoints are running high and decided to cut them back a couple of
degrees into the mid 70s. This still yields heat indices of 100 to
105.Tuesday may be another heat advisory day. Given the increasing
moisture and precipitable water values near 2.00 inches heavy rain
is also possible Tuesday night into Wednesday.

The flow aloft transition to more northwesterly Wednesday through
the remainder of the period. A shortwave dropping southward Thursday
through Friday will drive a cold front southward across the area and
scour out the higher temperatures and dewpoints. This will lower
high temperatures to near normal for the middle of August with high
temperatures generally in the lower 80s and dewpoints dropping into
the mid to upper 50s next weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
ISSUED AT 1245 PM CDT Sun Aug 8 2021

Mainly VFR conds but there are pockets of MVFR cigs. Othw
scattered thunderstorms should spread out of MO and into western
IL late this afternoon into this evening. This may graze the KBRL
taf so mentioned the potential for showers. If it looks like TSRA
will be headed towards the taf then I will amend. Models suggest
a band of thunderstorms moving southeast across the taf sites
after 05z/09 and lasting into Monday morning. These storms may
last for a few hours at each site with MVFR/lcl IFR conds in
heavier rain and maybe gusty winds. For now I have mentioned
prob30 and if confidence increases then a prevailing or even a tempo
group can be used.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

UPDATE...Sheets
SYNOPSIS...Sheets
SHORT TERM...Sheets
LONG TERM...Cousins
AVIATION...Haase
Hazardous weather outlook, Aug 8, 3:32 AM CDT, 10 hours 52 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
332 AM CDT Sun Aug 8 2021

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-090845-
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson-
Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson-
Warren-Hancock-McDonough-Scotland-Clark-
332 AM CDT Sun Aug 8 2021

This Hazardous Weather Outlook is for portions of north central
Illinois...northwest Illinois...west central Illinois...east
central Iowa...northeast Iowa...southeast Iowa and northeast
Missouri.

.DAY ONE...TODAY AND TONIGHT

Scattered thunderstorms are expected today and tonight.
Some storms this afternoon and evening may be severe, with
damaging wind and large hail the primary threats. The Storm
Prediction Center has a Slight Risk in place for areas roughly
southeast of a line from Dubuque to Williamsburg, Iowa. Locally
heavy rainfall will also be possible with slow moving storms.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Showers and thunderstorms are possible through mid week with another
round possible Thursday into Thursday night. There is a marginal
risk of severe thunderstorms across the outlook area on Monday and
Tuesday with the main threats being large hail and damaging
winds.

Heat and humidity will build across the area on Monday and Tuesday
with the potential for heat indices to exceed 100 degrees.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

Sheets/Cousins

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 8, 1:29 AM CDTSpecial Weather StatementDVNBenton31 min
Aug 8, 1:59 AM CDTSpecial Weather StatementDVNBenton31 min
Aug 8, 2:32 AM CDTSpecial Weather StatementDVNBenton28 min

Nearby

Heat Advisories in Iowa, 2021Heat Advisories in Illinois, 2021Heat Advisories in Missouri, 2021Every heat advisory in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.