Alert archive / Florida / Special Marine Warnings in 2021

Special Marine Warning 21, NWS Melbourne, FL

April 10, 2021

NWS Melbourne, FL issued this special marine warning at Apr 10, 2021, 6:06 PM EDT. It was in force for 84 min. 3 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: Apr 10, 2021, 6:06 PM EDT (22:06 UTC)
Expired: Apr 10, 2021, 7:30 PM EDT
In force: 84 min
Issued by: NWS Melbourne, FL
Area: Storm-based polygon
Hail: 0.0 in
Wind: 40.0 mph

The radar

The Melbourne radar (KMLB), 97 km from the middle of the area, began a volume at 22:10 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
Apr 10, 6:40 PM EDT	TSTM WND GST 50	4 Nw Haulover Canal, FL	USAF WIND TOWER 0421 MEASURED A PEAK WIND GUST OF 43KT OR 50MPH FROM THE WEST.
Apr 10, 6:47 PM EDT	TSTM WND GST 48	New Smyrna Beach Airpor, FL	AWOS AT NEW SMYRNA BEACH REGIONAL AIRPORT MEASURED A PEAK WIND GUST OF 42KT OR 48MPH FROM THE WNW.
Apr 10, 7:00 PM EDT	TSTM WND GST 51	3 S Playalinda Beach, FL	USAF WIND TOWER 0211 MEASURED A PEAK WIND GUST 44KT OR 51MPH FROM THE WEST.

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, 10.1 hours before the alert went out and 59 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: 1250 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

660 
WHUS52 KMLB 102206
SMWMLB
AMZ550-552-570-572-102330-
/O.NEW.KMLB.MA.W.0021.210410T2206Z-210410T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Melbourne FL
606 PM EDT Sat Apr 10 2021

The National Weather Service in Melbourne has issued a

* Special Marine Warning for...
  Flagler Beach to Volusia-Brevard County Line 0-20 nm...
  Flagler Beach to Volusia-Brevard County Line 20-60 nm...
  Volusia-Brevard County Line to Sebastian Inlet 0-20 nm...
  Volusia-Brevard County Line to Sebastian Inlet 20-60 nm...

* Until 730 PM EDT.

* At 605 PM EDT, a line of strong thunderstorms were located along a 
  line extending from 14 nm northeast of Daytona Beach Shores to 
  Sharpes, moving east at 35 knots.

  HAZARD...Wind gusts to 40 knots possible.

  SOURCE...Radar.

  IMPACT...Expect wind gusts in excess of 34 knots...suddenly higher 
           waves...lightning and heavy downpours. Make sure all on 
           board are wearing life jackets. Return to safe harbor if 
           possible.

* Locations impacted include...
  Playalinda Beach, Klondike Beach, Sharpes, Haulover Canal and
  Kennedy Space Center.

LAT...LON 2948 8029 2843 7988 2830 8046 2831 8073
      2880 8089 2884 8085 2927 8107 2946 8109
      2948 8072
TIME...MOT...LOC 2205Z 269DEG 91KT 2932 8077 2842 8077 

HAIL...0.00IN
WIND...40KTS

$$

Pendergrast

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 10, 2:49 AM EDT	Small Craft Advisory	MLB		25 hr
Apr 10, 3:29 AM EDT	Beach Hazards Statement	MLB	Volusia	16 hr
Apr 10, 4:08 AM EDT	Red Flag Warning	MLB	Lake, Okeechobee, Orange, Osceola, Seminole, Volusia	15 hr
Apr 10, 5:08 PM EDT	Special Weather Statement	MLB	Lake, Orange	82 min
Apr 10, 5:56 PM EDT	Special Weather Statement	MLB	Brevard, Seminole, Volusia	64 min
Apr 10, 6:33 PM EDT	Special Weather Statement	MLB	Okeechobee, Osceola	87 min
Apr 10, 6:56 PM EDT	Special Marine Warning	MLB		94 min
Apr 10, 7:12 PM EDT	Special Weather Statement	MLB	Indian River, Martin, Saint Lucie	63 min
Apr 10, 7:31 PM EDT	Special Marine Warning	MLB		89 min

Nearby

Special Marine Warnings in Florida, 2021 Every special marine 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.