Alert archive / Tennessee / Dense Fog Advisories in 2021

Dense Fog Advisory 9, NWS Memphis, TN

July 24, 20219 counties in Mississippi; 17 counties in Tennessee; Clay County, Arkansas

NWS Memphis, TN issued this dense fog advisory at Jul 24, 2021, 4:51 AM CDT for 9 counties in Mississippi; 17 counties in Tennessee; Clay County, Arkansas. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 24, 2021, 4:51 AM CDT (09:51 UTC)
Expired
Jul 24, 2021, 7:41 AM CDT
In force
3 hr
Issued by
NWS Memphis, TN
All 27 counties

Clay County, AR, Alcorn County, MS, Benton County, MS, Itawamba County, MS, Lee County, MS, Monroe County, MS, Prentiss County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 99 km from the middle of the area, began a volume at 09:55 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

Little Rock, AR (KLZK), launched 00:00Z, 9.9 hours before the alert went out and 124 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, Little Rock, AR at 00:00Z on 2021-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 835 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, Little Rock, AR at 00:00Z on 2021-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 square meters per square second.1939Sfc1 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
835 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
1427 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
-5 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Memphis, TN wrote its last area forecast discussion before this dense fog advisory went out at Jul 24, 4:27 AM CDT, 24 minutes earlier.

Area forecast discussion, Jul 24, 4:27 AM CDT, 24 minutes before
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Hazardous weather outlook, Jul 24, 4:36 AM CDT, 15 minutes before
Hazardous Weather Outlook
National Weather Service Memphis TN
436 AM CDT Sat Jul 24 2021

ARZ009-018-026>028-035-036-048-049-058-MOZ113-115-MSZ001>017-
020>024-TNZ001>004-019>022-048>055-088>092-251145-
Alcorn-Benton MS-Benton TN-Calhoun-Carroll-Chester-Chickasaw-Clay-
Coahoma-Craighead-Crittenden-Crockett-Cross-DeSoto-Decatur-
Dunklin-Dyer-Fayette-Gibson-Greene-Hardeman-Hardin-Haywood-
Henderson-Henry-Itawamba-Lafayette-Lake-Lauderdale-Lee AR-Lee MS-
Madison-Marshall-McNairy-Mississippi-Monroe-Obion-Panola-Pemiscot-
Phillips-Poinsett-Pontotoc-Prentiss-Quitman-Shelby-St. Francis-
Tallahatchie-Tate-Tippah-Tipton-Tishomingo-Tunica-Union-Weakley-
Yalobusha-
436 AM CDT Sat Jul 24 2021

This hazardous weather outlook is for portions of East Arkansas...
the Missouri Bootheel...North Mississippi...and West Tennessee.

.DAY ONE...Today and Tonight

A Heat advisory is in effect from 11 AM to 7 PM for portions of
northwest Mississippi, west Tennessee and east Arkansas. Heat
index values will be near 105 this afternoon.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Hot and humid conditions will stretch through the week, with heat
index values in the triple digits.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated at this time.

SMW

In the hours before

Special weather statement, Jul 24, 3:18 AM CDT, 1 hour 33 minutes before
Special Weather Statement
National Weather Service Memphis TN
318 AM CDT Sat Jul 24 2021

ARZ009-018-028-036-MOZ113-115-MSZ001>017-020>024-TNZ001>004-
019>022-048>055-088>092-241230-
Clay-Greene-Mississippi-Crittenden-Dunklin-Pemiscot-DeSoto-
Marshall-Benton MS-Tippah-Alcorn-Tishomingo-Tunica-Tate-Prentiss-
Coahoma-Quitman-Panola-Lafayette-Union-Pontotoc-Lee MS-Itawamba-
Tallahatchie-Yalobusha-Calhoun-Chickasaw-Monroe-Lake-Obion-
Weakley-Henry-Dyer-Gibson-Carroll-Benton TN-Lauderdale-Tipton-
Haywood-Crockett-Madison-Chester-Henderson-Decatur-Shelby-Fayette-
Hardeman-McNairy-Hardin-
Including the cities of Piggott, Corning, Paragould, Blytheville,
West Memphis, Kennett, Caruthersville, Southaven, Olive Branch,
Holly Springs, Ashland, Ripley MS, Corinth, Iuka, Tunica,
Senatobia, Booneville, Clarksdale, Marks, Batesville, Oxford,
New Albany, Pontotoc, Tupelo, Fulton, Charleston, Water Valley,
Coffeeville, Bruce, Calhoun City, Houston, Okolona, Amory,
Aberdeen, Tiptonville, Union City, Martin, Dresden, Paris,
Dyersburg, Humboldt, Milan, Huntingdon, Camden, Ripley TN,
Covington, Brownsville, Alamo, Jackson, Henderson, Lexington,
Parsons, Decaturville, Bartlett, Germantown, Collierville,
Memphis, Millington, Somerville, Oakland, Bolivar, Selmer,
and Savannah
318 AM CDT Sat Jul 24 2021

...Patchy Dense Fog Early This Morning...

Patchy, dense fog will affect portions of the Mid-South through
the early morning hours, resulting in hazardous travel conditions
on area roads. Visibility will range from 2 to 4 miles in many
areas, but may be locally reduced to 1/2 mile or less at times,
especially near lakes, rivers, or other sources of moisture.
Motorists are advised to exercise caution on area roadways due to
the potential for rapidly changing visibility.

MJ

The office that day

Everything else NWS Memphis, TN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 24, 4:13 AM CDTHeat AdvisoryMEGCoahoma, DeSoto, Panola, Quitman, Tallahatchie, Tate and 1 more15 hr
Jul 24, 2:24 PM CDTHeat AdvisoryMEGAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more29 hr

Nearby

Dense Fog Advisories in Tennessee, 2021Dense Fog Advisories in Mississippi, 2021Dense Fog Advisories in Arkansas, 2021Every dense fog 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.