Alert archive / Arkansas / Flash Flood Watches in 2017

Flash Flood Watch 5, NWS Memphis, TN

May 20, 20177 counties in Arkansas

NWS Memphis, TN issued this flash flood watch at May 20, 2017, 6:15 AM CDT for 7 counties in Arkansas. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued: May 20, 2017, 6:15 AM CDT (11:15 UTC)
Expired: May 20, 2017, 2:34 PM CDT
In force: 8 hr
Issued by: NWS Memphis, TN
Flood severity: None

Counties Clay County, AR, Craighead County, AR, Greene County, AR, Lawrence County, AR, Mississippi County, AR, Poinsett County, AR, Randolph County, AR

The radar

The Memphis radar (KNQA), 101 km from the middle of the area, began a volume at 11:17 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 (KBYH), launched 00:00Z, 11.3 hours before the alert went out and 145 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: 1585 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 1413 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 108 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 4.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch 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 flash flood watch went out at May 20, 3:29 AM CDT, 2 hours 46 minutes earlier.

Area forecast discussion, May 20, 3:29 AM CDT, 2 hours 46 minutes before

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Hazardous weather outlook, May 20, 3:39 AM CDT, 2 hours 36 minutes before

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In the hours before

Special weather statement, May 20, 4:33 AM CDT, 1 hour 42 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 11:43 AM CDT	Special Weather Statement	MEG	Prentiss	47 min
May 20, 12:20 PM CDT	Special Weather Statement	MEG	Chickasaw	40 min
May 20, 1:05 PM CDT	Special Weather Statement	MEG	Chickasaw, Pontotoc	40 min
May 20, 4:33 AM CDT	Special Weather Statement	MEG	Clay, Greene, Lawrence	27 min

Nearby

Flash Flood Watches in Arkansas, 2017 Every flash flood watch in 2017

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.