Alert archive / Florida / Flash Flood Warnings in 2022

Flash Flood Warning 7, NWS Jacksonville, FL

September 29, 2022Saint Johns County, Florida

NWS Jacksonville, FL issued this flash flood warning at Sep 29, 2022, 11:21 AM EDT for Saint Johns County, Florida. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 29, 2022, 11:21 AM EDT (15:21 UTC)
Expired: Sep 29, 2022, 3:15 PM EDT
In force: 4 hr
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 70 km from the middle of the area, began a volume at 15:20 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

Jacksonville, FL (KJAX), launched 12:00Z, 3.4 hours before the alert went out and 71 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 518 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 155 m²/s²
0-3 km storm-relative helicity: 345 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 flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Jacksonville, FL wrote its last area forecast discussion before this flash flood warning went out at Sep 29, 7:29 AM EDT, 3 hours 52 minutes earlier.

Area forecast discussion, Sep 29, 7:29 AM EDT, 3 hours 52 minutes before

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In the hours before

Local storm report, Sep 29, 10:10 AM EDT, 1 hour 11 minutes before

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Local storm report, Sep 29, 10:21 AM EDT, 1 hour before

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Local storm report, Sep 29, 10:38 AM EDT, 43 minutes before

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Local storm report, Sep 29, 10:41 AM EDT, 40 minutes before

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Local storm report, Sep 29, 11:11 AM EDT, 10 minutes before

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Local storm report, Sep 29, 11:19 AM EDT, 2 minutes before

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The office that day

Everything else NWS Jacksonville, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 29, 4:13 AM EDT	Areal Flood Advisory	JAX	Flagler, Putnam, Saint Johns	7 hr
Sep 29, 5:27 AM EDT	Flood Watch	JAX	Clay, Duval, Flagler, Marion, Nassau, Putnam	11 hr
Sep 29, 12:00 PM EDT	Hurricane Warning	JAX		23 hr
Sep 29, 12:14 PM EDT	Flash Flood Warning Considerable damage threat	JAX	Flagler	3 hr
Sep 29, 3:08 PM EDT	Flash Flood Warning Considerable damage threat	JAX	Flagler, Saint Johns	6 hr

Nearby

Flash Flood Warnings in Florida, 2022 Every flash flood warning in 2022

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.