Alert archive / Florida / Flash Flood Warnings in 2021

Flash Flood Warning 90, NWS Mobile, AL

September 20, 2021Okaloosa County, Florida

NWS Mobile, AL issued this flash flood warning at Sep 20, 2021, 3:13 PM CDT for Okaloosa County, Florida. It was in force for 6 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 20, 2021, 3:13 PM CDT (20:13 UTC)
Expired: Sep 20, 2021, 9:15 PM CDT
In force: 6 hr
Issued by: NWS Mobile, AL
Area: Storm-based polygon
Flood severity: None

County Okaloosa County, FL

The radar

The Eglin Afb radar (KEVX), 69 km from the middle of the area, began a volume at 20:14 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.

What was reported inside it

Time	Report	Where	Remark
Sep 20, 3:20 PM CDT	FLASH FLOOD	1 Se Crestview, FL	STREETLIGHT AT HWY 85 & MAIN ST WAS STRUCK BY LIGHTNING CALL CAME IN AROUND 250PM. DISPATCH WAS SENT OUT AND ARRIVED ~320PM AND WATER WAS REPORTED COVERING THE ROADWAY AT THIS TIME.
Sep 20, 3:20 PM CDT	FLASH FLOOD	2 Sse Crestview, FL	WATER REPORTED COVERING ROADWAY AT THE INTERSECTION OF BROOKMEADE DR AND GOODWIN AVE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 8.2 hours before the alert went out and 224 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: 402 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 582 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

090 
WGUS54 KMOB 202013
FFWMOB
FLC091-210215-
/O.NEW.KMOB.FF.W.0090.210920T2013Z-210921T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mobile AL
313 PM CDT Mon Sep 20 2021

The National Weather Service in Mobile has issued a

* Flash Flood Warning for...
  Central Okaloosa County in northwestern Florida...

* Until 915 PM CDT Monday.

* At 313 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Crestview and Milligan.

Most of the heavy rainfall driving this event has fallen in well 
less than one hour.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3075 8665 3077 8661 3078 8652 3073 8651
      3070 8661 3072 8666 3074 8666

FLASH FLOOD...RADAR INDICATED

$$

The office that day

Everything else NWS Mobile, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 20, 12:50 PM CDT	Special Weather Statement	MOB	Santa Rosa	40 min
Sep 20, 1:02 PM CDT	Special Weather Statement	MOB	Santa Rosa	43 min
Sep 20, 1:24 PM CDT	Special Weather Statement	MOB	Okaloosa	51 min
Sep 20, 2:44 PM CDT	Special Weather Statement	MOB	Okaloosa	46 min
Sep 20, 3:01 PM CDT	Areal Flood Advisory	MOB	Okaloosa	3 hr

Nearby

Flash Flood Warnings in Florida, 2021 Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.