Alert archive / Florida / Flash Flood Warnings in 2021

Flash Flood Warning 2, NWS Melbourne, FL

November 21, 2021Saint Lucie County, Florida

NWS Melbourne, FL issued this flash flood warning at Nov 21, 2021, 2:04 PM EST for Saint Lucie County, Florida. It was in force for 3 hr. 5 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
Nov 21, 2021, 2:04 PM EST (19:04 UTC)
Expired
Nov 21, 2021, 5:00 PM EST
In force
3 hr
Issued by
NWS Melbourne, FL
Area
Storm-based polygon
Flood severity
None

County Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 91 km from the middle of the area, began a volume at 19:04 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

TimeReportWhereRemark
Nov 21, 2:20 PM ESTFLOOD5 N Port Saint Lucie, FLPUBLIC REPORT RETRIEVED VIA SNAPCHAT SHOWS WATER ACROSS NW ST JAMES DR NEAR NW PINE TRACE AVE. APPEARS TO BE 4 TO 6 INCHES IN SPOTS. TIME ESTIMATED.
Nov 21, 2:39 PM ESTFLASH FLOOD4 Nne Port Saint Lucie, FLPUBLIC REPORTS ROAD COMPLETELY UNDERWATER AT THE INTERSECTION OF OLEANDER AVE AND ASH STREET IN PSL. WATER IS UP TO THE FRONT OF SEVERAL HOMES.
Nov 21, 2:50 PM ESTFLOOD5 Nne Port Saint Lucie, FLPORT ST. LUCIE PD REPORTS FLOODING ACROSS THE ROAD AT US-1 AND KITTERMAN RD.
Nov 21, 2:50 PM ESTFLASH FLOOD4 Nne Port Saint Lucie, FLPORT ST. LUCIE PD REPORTS SOUTHBOUND US-1 AT PRIMA VISTA BOULEVARD IS CLOSED DUE TO FLOODING.
Nov 21, 2:50 PM ESTFLASH FLOOD4 Nne Port Saint Lucie, FLPORT ST. LUCIE POLICE DEPARTMENT REPORTS WATER APPROACHING HOMES IN THE 500 BLOCK OF OLEANDER AVE.

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

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 7.1 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, Cape Canaveral, FL at 12:00Z on 2021-11-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 170 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cape Canaveral, FL at 12:00Z on 2021-11-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 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
170 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
879 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

350 
WGUS52 KMLB 211904
FFWMLB
FLC111-212200-
/O.NEW.KMLB.FF.W.0002.211121T1904Z-211121T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Melbourne FL
204 PM EST Sun Nov 21 2021

The National Weather Service in Melbourne has issued a

* Flash Flood Warning for...
  Southeastern St. Lucie County in east central Florida...

* Until 500 PM EST.

* At 204 PM EST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  6 and 8 inches of rain have fallen. Additional rainfall amounts of 
  1 to 2 inches are possible in the warned area. Flash flooding is 
  ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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...
  Walton, Fort Pierce, White City, Saint Lucie Nuclear Power Plant, 
  Indian River Estates, Port Saint Lucie River Park, Fort Pierce 
  South, Saint Lucie West, Collins Park Estates, Frederick Douglass 
  Park, Hutchinson Island South, Tradition Field and Carlton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2742 8027 2743 8024 2742 8024 2741 8023
      2735 8020 2729 8018 2729 8025 2728 8037
      2740 8047

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$
1 follow-up statement
455 
WGUS72 KMLB 212002
FFSMLB

Flash Flood Statement
National Weather Service Melbourne FL
302 PM EST Sun Nov 21 2021

FLC111-212200-
/O.CON.KMLB.FF.W.0002.000000T0000Z-211121T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Lucie FL-
302 PM EST Sun Nov 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 5 PM EST THIS 
AFTERNOON FOR SOUTHEASTERN ST. LUCIE COUNTY...

At 302 PM EST, police dispatch reports flood waters approaching 
homes on Oleander Avenue in Port St Lucie and many roads along US 1 
with water across the road. Between 7.5 and 9.5 inches of rain have 
fallen. Additional rainfall amounts of 1 to 2 inches are possible in 
the warned area. Flash flooding is already occurring.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Law enforcement reported.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Walton, Fort Pierce, White City, Saint Lucie Nuclear Power Plant, 
  Indian River Estates, Port Saint Lucie River Park, Fort Pierce 
  South, Saint Lucie West, Collins Park Estates, Frederick Douglass 
  Park, Hutchinson Island South, Tradition Field and Carlton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2742 8027 2743 8024 2742 8024 2741 8023
      2735 8020 2729 8018 2729 8025 2728 8037
      2740 8047

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CL

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 21, 8:38 AM ESTAreal Flood AdvisoryMLBSaint Lucie112 min
Nov 21, 12:21 PM ESTAreal Flood AdvisoryMLBSaint Lucie114 min
Nov 21, 1:00 PM ESTAreal Flood AdvisoryMLBSaint Lucie75 min
Nov 21, 1:37 PM ESTAreal Flood WarningMLBSaint Lucie27 min
Nov 21, 2:32 PM ESTAreal Flood WarningMLBSaint Lucie2 hr
Nov 21, 3:36 PM ESTAreal Flood AdvisoryMLBMartin, Saint Lucie84 min
Nov 21, 5:00 PM ESTAreal Flood WarningMLBSaint Lucie2 hr

Nearby

Flash Flood Warnings in Florida, 2021Every 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.