Heat Advisory 4, NWS St. Louis, MO

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Jefferson County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Madison County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

668 
WWUS73 KLSX 090739
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
239 AM CDT Mon Aug 9 2021

ILZ058-079-095>102-MOZ018-019-026-027-034>036-041-042-047>052-
059>065-072>075-084-085-099-092245-
/O.EXT.KLSX.HT.Y.0004.210809T1600Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Madison IL-Saint Clair-Monroe IL-Knox MO-Lewis MO-Shelby MO-
Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-Audrain MO-Moniteau
MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-Lincoln MO-
Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-Saint Louis
MO-Saint Louis City MO-Jefferson MO-Crawford MO-Washington MO-
Saint Francois MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds
MO-
Including the cities of Saint Louis, Farmington, Mount Sterling,
Cahokia, Quincy, Pittsfield, Alton, Union, Washington, Sparta,
Bowling Green, Mexico, Jefferson City, Belleville, Edwardsville,
Chester, Saint Charles, Columbia, Hannibal, Sullivan, and Fulton
239 AM CDT Mon Aug 9 2021

...HEAT ADVISORY NOW IN EFFECT FROM 11 AM THIS MORNING TO 8 PM CDT 
THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...From 11 AM this morning to 8 PM CDT Thursday.

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

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.

&&

$$

MRB

419 
WWUS73 KLSX 091948
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
248 PM CDT Mon Aug 9 2021

ILZ059-060-064-065-069-070-074-101100-
/O.EXB.KLSX.HT.Y.0004.210810T1700Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
248 PM CDT Mon Aug 9 2021

...HEAT ADVISORY IN EFFECT FROM NOON TUESDAY TO 8 PM CDT THURSDAY...

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...From Noon Tuesday to 8 PM CDT Thursday.

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

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.

&&

$$

ILZ058-079-095>102-MOZ018-019-026-027-034>036-041-042-047>052-
059>065-072>075-084-085-099-101100-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Madison IL-Saint Clair-Monroe IL-Knox MO-Lewis MO-Shelby MO-
Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-Audrain MO-Moniteau
MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-Lincoln MO-
Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-Saint Louis
MO-Saint Louis City MO-Jefferson MO-Crawford MO-Washington MO-
Saint Francois MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds
MO-
Including the cities of Saint Louis, Farmington, Mount Sterling,
Cahokia, Quincy, Pittsfield, Alton, Union, Washington, Sparta,
Bowling Green, Mexico, Jefferson City, Belleville, Edwardsville,
Chester, Saint Charles, Columbia, Hannibal, Sullivan, and Fulton
248 PM CDT Mon Aug 9 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

Byrd

834 
WWUS73 KLSX 100820
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
320 AM CDT Tue Aug 10 2021

ILZ100-101-MOZ061-063-064-102330-
/O.UPG.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
/O.NEW.KLSX.EH.W.0001.210810T1700Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
320 AM CDT Tue Aug 10 2021

...EXCESSIVE HEAT WARNING IN EFFECT FROM NOON TODAY TO 8 PM CDT 
THURSDAY...

* WHAT...Dangerously hot conditions with heat index values up to 110 
  expected.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...From Noon today to 8 PM CDT Thursday.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

&&

$$

ILZ058-079-095>099-102-MOZ018-019-026-027-034>036-041-042-047>052-
059-060-062-065-072>075-084-085-099-102330-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Monroe IL-Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls
MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole MO-Osage MO-
Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-
Franklin MO-Jefferson MO-Crawford MO-Washington MO-Saint Francois
MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Columbia, Quincy,
Pittsfield, Sparta, Union, Washington, Mexico, Bowling Green,
Jefferson City, Chester, Farmington, Sullivan, Hannibal, and
Fulton
320 AM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-102330-
/O.CON.KLSX.HT.Y.0004.210810T1700Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
320 AM CDT Tue Aug 10 2021

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

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...From Noon today to 8 PM CDT Thursday.

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

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.

&&

$$

Glass

278 
WWUS73 KLSX 102022
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
322 PM CDT Tue Aug 10 2021

ILZ100-101-MOZ061-063-064-111130-
/O.CON.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
322 PM CDT Tue Aug 10 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT 
THURSDAY...

* WHAT...Dangerously hot conditions with heat index values up to 113.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...Until 8 PM CDT Thursday.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

&&

$$

ILZ058-079-095>099-102-MOZ018-019-026-027-034>036-041-042-047>052-
059-060-062-065-072>075-084-085-099-111130-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Monroe IL-Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls
MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole MO-Osage MO-
Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-
Franklin MO-Jefferson MO-Crawford MO-Washington MO-Saint Francois
MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Columbia, Quincy,
Pittsfield, Sparta, Union, Washington, Mexico, Bowling Green,
Jefferson City, Chester, Farmington, Sullivan, Hannibal, and
Fulton
322 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-111130-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
322 PM CDT Tue Aug 10 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

* WHAT...Heat index values up to 112.

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

Pfahler

294 
WWUS73 KLSX 110839
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
339 AM CDT Wed Aug 11 2021

ILZ100-101-MOZ061-063-064-112345-
/O.CON.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
339 AM CDT Wed Aug 11 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT 
THURSDAY...

* WHAT...Dangerously hot conditions with heat index values up to 110.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...Until 8 PM CDT Thursday.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

&&

$$

ILZ058-079-095>099-102-MOZ018-019-026-027-034>036-041-042-047>052-
059-060-062-065-072>075-084-085-099-112345-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Monroe IL-Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls
MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole MO-Osage MO-
Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-
Franklin MO-Jefferson MO-Crawford MO-Washington MO-Saint Francois
MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Columbia, Quincy,
Pittsfield, Sparta, Union, Washington, Mexico, Bowling Green,
Jefferson City, Chester, Farmington, Sullivan, Hannibal, and
Fulton
339 AM CDT Wed Aug 11 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-112345-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
339 AM CDT Wed Aug 11 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

Glass

549 
WWUS73 KLSX 111943
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
243 PM CDT Wed Aug 11 2021

ILZ100-101-MOZ061-063-064-121045-
/O.CON.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
243 PM CDT Wed Aug 11 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT 
THURSDAY...

* WHAT...Dangerously hot conditions with heat index values up to 111.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...Until 8 PM CDT Thursday.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

&&

$$

ILZ058-079-095>099-102-MOZ018-019-026-027-034>036-041-042-047>052-
059-060-062-065-072>075-084-085-099-121045-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Monroe IL-Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls
MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole MO-Osage MO-
Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-
Franklin MO-Jefferson MO-Crawford MO-Washington MO-Saint Francois
MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Columbia, Quincy,
Pittsfield, Sparta, Union, Washington, Mexico, Bowling Green,
Jefferson City, Chester, Farmington, Sullivan, Hannibal, and
Fulton
243 PM CDT Wed Aug 11 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-121045-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
243 PM CDT Wed Aug 11 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THURSDAY...

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...Until 8 PM CDT Thursday.

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

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.

&&

$$

Pfahler

195 
WWUS73 KLSX 120904
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
404 AM CDT Thu Aug 12 2021

ILZ100-101-MOZ061-063-064-130015-
/O.CON.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
404 AM CDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT THIS 
EVENING...

* WHAT...Dangerously hot conditions with heat index values up to 110.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...Until 8 PM CDT this evening.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

Do not leave young children and pets in unattended vehicles. Car 
interiors will reach lethal temperatures in a matter of minutes.

&&

$$

ILZ058-079-095>099-102-MOZ018-019-026-027-034>036-041-042-047>052-
059-060-062-065-072>075-084-085-099-130015-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Adams IL-Brown IL-Pike IL-Calhoun IL-Jersey
IL-Monroe IL-Knox MO-Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls
MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole MO-Osage MO-
Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-Warren MO-
Franklin MO-Jefferson MO-Crawford MO-Washington MO-Saint Francois
MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Columbia, Quincy,
Pittsfield, Sparta, Union, Washington, Mexico, Bowling Green,
Jefferson City, Chester, Farmington, Sullivan, Hannibal, and
Fulton
404 AM CDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...

* WHAT...Heat index values up to 105.

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT this evening.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-130015-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
404 AM CDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...Until 8 PM CDT this evening.

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

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.

&&

$$

Glass

609 
WWUS73 KLSX 121956
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
256 PM CDT Thu Aug 12 2021

ILZ095-096-MOZ018-019-026-027-122100-
/O.CAN.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Adams IL-Brown IL-Knox MO-Lewis MO-Shelby MO-Marion MO-
Including the cities of Hannibal, Mount Sterling, and Quincy
256 PM CDT Thu Aug 12 2021

...HEAT ADVISORY IS CANCELLED...

Showers and thunderstorms have significantly cooled temperatures 
this afternoon across the area. Therefore, heat index values are no 
longer expected to reach dangerous levels.

$$

ILZ100-101-MOZ061-063-064-130100-
/O.CON.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
256 PM CDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT THIS 
EVENING...

* WHAT...Dangerously hot conditions with heat index values up to 107.

* WHERE...In Missouri, Saint Charles MO, Saint Louis City MO and 
  Saint Louis MO Counties. In Illinois, Madison IL and Saint Clair 
  Counties.

* WHEN...Until 8 PM CDT this evening.

* IMPACTS...Heat related illnesses increase significantly during 
  extreme heat and high humidity events.

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.

Do not leave young children and pets in unattended vehicles. Car 
interiors will reach lethal temperatures in a matter of minutes.

&&

$$

ILZ058-079-097>099-102-MOZ034>036-041-042-047>052-059-060-062-065-
072>075-084-085-099-130100-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Randolph IL-Pike IL-Calhoun IL-Jersey IL-Monroe IL-
Monroe MO-Ralls MO-Pike MO-Boone MO-Audrain MO-Moniteau MO-Cole
MO-Osage MO-Callaway MO-Montgomery MO-Lincoln MO-Gasconade MO-
Warren MO-Franklin MO-Jefferson MO-Crawford MO-Washington MO-
Saint Francois MO-Sainte Genevieve MO-Iron MO-Madison MO-Reynolds
MO-
Including the cities of Columbia, Pittsfield, Mexico, Union,
Washington, Sparta, Bowling Green, Jefferson City, Chester,
Farmington, Sullivan, and Fulton
256 PM CDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...

* WHAT...Heat index values up to 105.

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central, east central, northeast, and southeast Missouri.

* WHEN...Until 8 PM CDT this evening.

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

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.

&&

$$

ILZ059-060-064-065-069-070-074-130100-
/O.CON.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-Marion IL-
Washington IL-
Including the cities of Litchfield, Centralia, Salem, and
Vandalia
256 PM CDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...

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

* WHERE...Bond IL, Clinton IL, Fayette IL, Marion IL, Montgomery IL, 
  Washington IL and Macoupin IL Counties.

* WHEN...Until 8 PM CDT this evening.

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

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.

&&

$$

Pfahler

321 
WWUS73 KLSX 130054
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
754 PM CDT Thu Aug 12 2021

ILZ100-101-MOZ061-063-064-130200-
/O.EXP.KLSX.EH.W.0001.000000T0000Z-210813T0100Z/
Madison IL-Saint Clair-Saint Charles MO-Saint Louis MO-Saint
Louis City MO-
Including the cities of Saint Charles, Cahokia, Alton, Saint
Louis, Belleville, and Edwardsville
754 PM CDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING WILL EXPIRE AT 8 PM CDT THIS EVENING...

Cooler air has moved into the region ending the dangerous heat.

$$

ILZ058>060-064-065-069-070-074-079-097>099-102-MOZ034>036-041-042-
047>052-059-060-062-065-072>075-084-085-099-130200-
/O.EXP.KLSX.HT.Y.0004.000000T0000Z-210813T0100Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Pike IL-Calhoun IL-Jersey IL-
Monroe IL-Monroe MO-Ralls MO-Pike MO-Boone MO-Audrain MO-Moniteau
MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-Lincoln MO-
Gasconade MO-Warren MO-Franklin MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Columbia, Pittsfield, Sparta, Litchfield,
Washington, Mexico, Bowling Green, Centralia, Jefferson City,
Salem, Chester, Union, Farmington, Sullivan, Vandalia, and Fulton
754 PM CDT Thu Aug 12 2021

...HEAT ADVISORY WILL EXPIRE AT 8 PM CDT THIS EVENING...

Cooler air has moved into the region ending the dangerous heat.

$$

Britt

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1239 PM CDT Sun Aug 8 2021

.SHORT TERM...  (Through Late Monday Afternoon)
Issued at 310 AM CDT Sun Aug 8 2021

Key messages through Monday afternoon:

1) The potential for strong to severe thunderstorms remains elevated
across most of the area this afternoon and evening. Damaging wind
and large hail are the predominant threats, but flash flooding could
also be of concern.

2) Humidity will continue to build across the region Monday, which
could result in heat indices over 100F if lingering clouds and
convection do not hinder temperatures.

An upper-level trough, currently providing synoptic support to a
decaying MCS in eastern KS/western MO, will continue to propagate
east overnight and provide the focus for thunderstorms today. Latest
surface analysis shows a warm, humid airmass across most of the
Mississippi Valley, with sub-65F dewpoints at a premium. Southerly
low-level flow is beginning to strengthen in advance of the MCS and
amidst a tightening surface pressure gradient. Lingering clouds from
this morning's convection will work to restrict our high
temperatures today, despite stronger low-level winds, but we should
still reach the upper 80s/low-90s.

CAMs differ on the timing of CI and convective evolution, but it
appears that the majority of the storms should develop with the
passage of a vortmax through the CWA early this afternoon. There are
some indication of isolated CI ahead of the synoptic mid-level
forcing during the late morning, which may serve to destabilize the
cap in advance of the stronger storms. Most guidance continues to
produce elevated surface dewpoints and does not properly handle
diurnal mixing, but it is clear that more-than-sufficient SBCAPE
will be available to the forcing to produce scattered strong/severe
thunderstorms during the afternoon.

0-6km bulk shear appears slightly weaker among the current suite of
deterministic and HREF guidance, which could serve to limit
organized storm development and favor quick upscale growth. Mid-
level lapse rates of 6.5-7.0C/km, combined with the robust
updrafts expected from even a conservative CAPE estimate, could
pose an initial threat of both large hail and damaging wind.
However, with weak deep-layer shear, upscale growth should occur
quickly and the threat shifts more to damaging wind. This threat
extends across eastern MO and western IL, but the greatest concern
remains across central/northeast MO and west-central IL during
the afternoon and early evening.

As the initial synoptic forcing moves east and the base of the
shortwave crosses the CWA, the threat for severe storms should
transition to one for flash flooding. Guidance continues to
indicate that an outflow boundary will set up across part of the
area and provide the focus for training thunderstorms to cause
heavy rain for several hours. HREF probability-matched mean 3-hr
QPF highlight southeast MO for potentially 1"+/hr rain rates
Sunday evening through early Monday morning. However, there is
uncertainty as to where this boundary sets up, which could shift
this axis of heavy rain north or south accordingly. With IVT
values still expected to exceed the 90th climatological
percentile, aided by a 30- 35kt LLJ, plentiful moisture could
interact with this boundary and produce instances of flash
flooding for some across the area, with focus on southeast/south-
central MO.

The upper-level shortwave will begin to exit the area Monday
morning, pulling synoptic support for precipitation with it. Some
guidance is more sluggish in clearing the shortwave, and if
convective activity can sustain itself through the night along the
nose of the LLJ, it could help reinvigorate showers and storms
Monday. While bulk shear looks a bit more robust later Monday
morning across southwest/west-central IL, the quality of the airmass
is in question after the activity overnight. Given this, while an
isolated strong storm cannot be ruled out before the system exits
the CWA, most of the robust convection should be east of us.
Decreasing clouds from west to east will help central MO warm a
degree or two higher than eastern MO and western IL, but we should
still reach at least the upper 80s areawide. At this point, the
greatest chance for 100F+ heat indices rests in central/northeast
MO, where warmer temperatures and higher humidity will overlap.

MRB

.LONG TERM...  (Monday Night through Saturday)
Issued at 310 AM CDT Sun Aug 8 2021

Key messages through the extended forecast period:

1) Elevated heat and humidity is possible through Thursday, with the
potential for dangerous heat indices across most of the area Tuesday.

2) Several rounds of energy, which should help spur daily threats
for thunderstorms, may eventually help push a weak cold front
through the area. This could bring a brief, but welcomed, respite
from heat concerns.

Upper-level ridging will build into the region Monday night, setting
up Tuesday to potentially be the warmest and most humid day of the
week. NAEFS and GEFS guidance point to 850mb temperatures near the
90th percentile, but surface humidity could help push heat indices
into the triple digits. However, Tuesday could also see convective
activity which would act against warmer temperatures. Deterministic
models are in agreement that a subtle shortwave will traverse the
northern portion of the area, which could spark thunderstorms.
Several sources of uncertainty remain, namely whether or not this
consensus of such a subtle feature is accurate and whether the
storms would occur after peak heating. With several consecutive
days featuring heat indices over 100F, a Heat Advisory is
certainly possible. However, my confidence regarding marginally-
high heat indices is low given the potential for convection to
restrict temperatures, as such no Heat Advisory was issued.

Several rounds of shortwave impulses traversing the base of a
longwave trough, modeled to set up across southern Canada, will help
to gradually push a boundary through the region later this week. As
such, the chance for precipitation remains non-zero during the
afternoon each day of the extended period as this energy interacts
with moisture on the warmer side of the boundary. WPC Cluster
Analysis depicts the uncertainty that exists with respect to the
upper-level flow pattern late this week. One cluster, which
represent nearly one-third of the members, has a more expansive
ridge across most of the CONUS, restricting cooler air to the north.
As of now, the forecast reflects a gradual but notable cooldown
compared to recent conditions.

MRB

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1224 PM CDT Sun Aug 8 2021

Thunderstorms are expected to develop across the region this
afternoon and will likely affect all of the terminals between
20-24Z with IFR visibilities in heavy rainfal, MVFR or IFR
ceilings, wind gusts to 35 knots or higher, and possibly some
hail. Thunderstorms will continue into the evening hours before
diminshing overnight with generally dry and VFR conditions expect
late tonight into Monday morning. Only exception will be at KUIN
where low ceilings are expected to linger.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

WFO LSX

Hazardous Weather Outlook
National Weather Service Saint Louis MO
319 AM CDT Sun Aug 8 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-090830-
Adams IL-Audrain MO-Bond IL-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Clinton IL-Cole MO-Crawford MO-Fayette IL-Franklin MO-Gasconade MO-
Greene IL-Iron MO-Jefferson MO-Jersey IL-Knox MO-Lewis MO-Lincoln MO-
Macoupin IL-Madison IL-Madison MO-Marion IL-Marion MO-Moniteau MO-
Monroe IL-Monroe MO-Montgomery IL-Montgomery MO-Osage MO-Pike IL-
Pike MO-Ralls MO-Randolph IL-Reynolds MO-Saint Charles MO-
Saint Clair-Saint Francois MO-Saint Louis City MO-Saint Louis MO-
Sainte Genevieve MO-Shelby MO-Warren MO-Washington IL-Washington MO-
319 AM CDT Sun Aug 8 2021

This Hazardous Weather Outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Today and tonight.

Scattered thunderstorms are expected today and tonight. A few of the
thunderstorms this afternoon and evening could be severe, with large
hail and damaging winds being the main threats. Locally heavy
rainfall will also be possible this afternoon into tonight, which
could result in isolated instances of flash flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

There is a chance for thunderstorms over portions of the area
from Monday morning through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to send reports of wind damage or large hail
to the National Weather Service.

MRB