Alert archive / Missouri / Heat Advisories in 2014

Heat Advisory 3, NWS St. Louis, MO

August 20, 201427 counties in Missouri; 15 counties in Illinois

NWS St. Louis, MO issued this heat advisory at Aug 20, 2014, 3:10 AM CDT for 27 counties in Missouri; 15 counties in Illinois. It took effect at Aug 20, 2014, 1:00 PM CDT. It was in force for 7 days.

The area

The counties it named.

The facts

Issued: Aug 20, 2014, 3:10 AM CDT (08:10 UTC)
In effect from: Aug 20, 2014, 1:00 PM CDT
Expired: Aug 27, 2014, 8:00 PM CDT
In force: 7 days
Issued by: NWS St. Louis, MO

All 42 counties

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, Marion County, IL, Monroe County, IL, Montgomery County, IL, Pike County, IL, Randolph County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, 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, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 23 km from the middle of the area, began a volume at 08:12 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, 8.2 hours before the alert went out and 245 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 368 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 1578 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

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 St. Louis, MO wrote its last area forecast discussion before this heat advisory went out at Aug 19, 11:10 PM CDT, 4 hours earlier.

Area forecast discussion, Aug 19, 11:10 PM CDT, 4 hours before

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Hazardous weather outlook, Aug 19, 3:59 PM CDT, 11 hours 11 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
359 PM CDT TUE AUG 19 2014

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-201115-
GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL-
MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL-
CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR 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-ST. CHARLES MO-FRANKLIN MO-
ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO-
WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO-
MADISON MO-REYNOLDS MO-
359 PM CDT TUE AUG 19 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND
CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS.

.DAY ONE...TONIGHT

THERE IS A CHANCE FOR THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS WEDNESDAY AND
WEDNESDAY NIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE REGION.

A DANGEROUS COMBINATION OF HEAT AND HUMIDITY WILL BUILD ACROSS
THE ST. LOUIS METROPOLITAN AREA WEDNESDAY THROUGH SUNDAY. AN
EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR HEAT INDEX VALUES
REACHING OR EXCEEDING 105 DEGREES EACH AFTERNOON.

LOCATIONS OUTSIDE OF THE URBAN HEAT ISLAND OF ST. LOUIS MAY ALSO
SEE AFTERNOON HEAT INDEX VALUES AROUND 105 DEGREES BEGINNING ON
FRIDAY AND LASTING INTO THE WEEKEND.

THERE IS ANOTHER CHANCE OF THUNDERSTORMS ON SUNDAY NIGHT AND MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH THIS EVENING.

CVKING

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 7:34 AM CDT	Severe Thunderstorm Warning	LSX	Jersey, Macoupin	41 min

Nearby

Heat Advisories in Missouri, 2014 Heat Advisories in Illinois, 2014 Every heat advisory in 2014

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.