Alert archive / Missouri / Heat Advisories in 2021
Heat Advisory 2, NWS St. Louis, MO
NWS St. Louis, MO issued this heat advisory at Jul 23, 2021, 3:04 AM CDT for 5 counties in Missouri; 5 counties in Illinois. It took effect at Jul 24, 2021, 12:00 PM CDT. It was in force for 8 hr.
The area
The counties it named.
The facts
- Issued
- Jul 23, 2021, 3:04 AM CDT (08:04 UTC)
- In effect from
- Jul 24, 2021, 12:00 PM CDT
- Expired
- Jul 24, 2021, 8:00 PM CDT
- In force
- 8 hr
- Issued by
- NWS St. Louis, MO
Counties Calhoun County, IL, Jersey County, IL, Madison County, IL, Monroe County, IL, Saint Clair County, IL, City of Saint Louis, MO, Jefferson County, MO, Lincoln County, MO, Saint Charles County, MO, Saint Louis County, MO
The radar
The St Louis radar (KLSX), 26 km from the middle of the area, began a volume at 08:06 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
Lincoln, IL (KILX), launched 00:00Z, 8.1 hours before the alert went out and 221 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.
- Mixed-layer CAPE
- 531 J/kg
- Mixed-layer CIN
- -16 J/kg
- Mixed-layer LCL
- 1458 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 8 m²/s²
- 0-3 km storm-relative helicity
- 28 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
696 WWUS73 KLSX 230804 NPWLSX URGENT - WEATHER MESSAGE National Weather Service St Louis MO 304 AM CDT Fri Jul 23 2021 ILZ098>102-MOZ052-061-063>065-232315- /O.NEW.KLSX.HT.Y.0002.210724T1700Z-210725T0100Z/ Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Lincoln MO- Saint Charles MO-Saint Louis MO-Saint Louis City MO-Jefferson MO- Including the cities of Saint Charles, Cahokia, Alton, Saint Louis, Belleville, and Edwardsville 304 AM CDT Fri Jul 23 2021 ...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM CDT SATURDAY... * WHAT...Heat index values up to 105 expected. * WHERE...In Missouri, Jefferson MO, Lincoln MO, Saint Charles MO, Saint Louis City MO and Saint Louis MO Counties. In Illinois, Calhoun IL, Jersey IL, Madison IL, Monroe IL and Saint Clair Counties. * WHEN...From Noon to 8 PM CDT Saturday. * 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. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. && $$ MRB
4 follow-up statements
272 WWUS73 KLSX 231952 NPWLSX URGENT - WEATHER MESSAGE National Weather Service St Louis MO 252 PM CDT Fri Jul 23 2021 ILZ098>102-MOZ052-061-063>065-241100- /O.CON.KLSX.HT.Y.0002.210724T1700Z-210725T0100Z/ Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Lincoln MO- Saint Charles MO-Saint Louis MO-Saint Louis City MO-Jefferson MO- Including the cities of Saint Charles, Cahokia, Alton, Saint Louis, Belleville, and Edwardsville 252 PM CDT Fri Jul 23 2021 ...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TO 8 PM CDT SATURDAY... * WHAT...Heat index values up to 105 expected. * WHERE...In Missouri, Jefferson MO, Lincoln MO, Saint Charles MO, Saint Louis City MO and Saint Louis MO Counties. In Illinois, Calhoun IL, Jersey IL, Madison IL, Monroe IL and Saint Clair Counties. * WHEN...From Noon to 8 PM CDT Saturday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. PRECAUTIONARY/PREPAREDNESS ACTIONS... Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. && $$ Glass
709 WWUS73 KLSX 240809 NPWLSX URGENT - WEATHER MESSAGE National Weather Service St Louis MO 309 AM CDT Sat Jul 24 2021 ILZ098>102-MOZ052-061-063>065-242315- /O.CON.KLSX.HT.Y.0002.210724T1700Z-210725T0100Z/ Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Lincoln MO- Saint Charles MO-Saint Louis MO-Saint Louis City MO-Jefferson MO- Including the cities of Saint Charles, Cahokia, Alton, Saint Louis, Belleville, and Edwardsville 309 AM CDT Sat Jul 24 2021 ...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM CDT THIS EVENING... * WHAT...Heat index values up to 105 expected. * WHERE...In Missouri, Jefferson MO, Lincoln MO, Saint Charles MO, Saint Louis City MO and Saint Louis MO Counties. In Illinois, Calhoun IL, Jersey IL, Madison IL, Monroe IL and Saint Clair Counties. * WHEN...From Noon today to 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. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. && $$ MRB
054 WWUS73 KLSX 241936 NPWLSX URGENT - WEATHER MESSAGE National Weather Service St Louis MO 236 PM CDT Sat Jul 24 2021 ILZ098>102-MOZ052-061-063>065-250100- /O.CON.KLSX.HT.Y.0002.000000T0000Z-210725T0100Z/ Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Lincoln MO- Saint Charles MO-Saint Louis MO-Saint Louis City MO-Jefferson MO- Including the cities of Saint Charles, Cahokia, Alton, Saint Louis, Belleville, and Edwardsville 236 PM CDT Sat Jul 24 2021 ...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING... * WHAT...Heat index values up to 106. * WHERE...In Missouri, Jefferson MO, Lincoln MO, Saint Charles MO, Saint Louis City MO and Saint Louis MO Counties. In Illinois, Calhoun IL, Jersey IL, Madison IL, Monroe IL and Saint Clair Counties. * WHEN...Until 8 PM CDT this evening. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. PRECAUTIONARY/PREPAREDNESS ACTIONS... Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. && $$ Glass
072 WWUS73 KLSX 250054 NPWLSX URGENT - WEATHER MESSAGE National Weather Service Saint Louis MO 754 PM CDT Sat Jul 24 2021 ILZ098>102-MOZ052-061-063>065-250200- /O.EXP.KLSX.HT.Y.0002.000000T0000Z-210725T0100Z/ Calhoun IL-Jefferson MO-Jersey IL-Lincoln MO-Madison IL-Monroe IL- Saint Charles MO-Saint Clair-Saint Louis City MO-Saint Louis MO- Including the cities of Alton, Belleville, Cahokia, Edwardsville, Saint Charles, and Saint Louis 754 PM CDT Sat Jul 24 2021 ...HEAT ADVISORY WILL EXPIRE AT 8 PM CDT THIS EVENING... The threat has ended as temperatures slowly cool this evening. Slightly cooler temperatures are expected on Sunday after passage of a cold front. $$ Byrd
Nearby
Heat Advisories in Missouri, 2021Heat Advisories in Illinois, 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.