Alert archive / Florida / Special Marine Warnings in 2021

Special Marine Warning 430, NWS Miami, FL

September 1, 2021

NWS Miami, FL issued this special marine warning at Sep 1, 2021, 6:00 PM EDT. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 1, 2021, 6:00 PM EDT (22:00 UTC)
Expired
Sep 1, 2021, 6:48 PM EDT
In force
48 min
Issued by
NWS Miami, FL
Area
Storm-based polygon
Hail
0.75 in
Wind
34.0 mph

The radar

The Miami radar (KAMX), 83 km from the middle of the area, began a volume at 22:00 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

Miami, FL (KMFL), launched 12:00Z, 10.0 hours before the alert went out and 57 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, Miami, FL at 12:00Z on 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1720 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, Miami, FL at 12:00Z on 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
1720 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
876 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

579 
WHUS52 KMFL 012200
SMWMFL
AMZ650-651-012300-
/O.NEW.KMFL.MA.W.0430.210901T2200Z-210901T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Miami FL
600 PM EDT Wed Sep 1 2021

The National Weather Service in Miami has issued a

* Special Marine Warning for...
  Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM...
  Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20
  NM...

* Until 700 PM EDT.

* At 600 PM EDT, a severe thunderstorm capable of producing
  waterspouts was located over Hillsboro Beach, or over Lighthouse
  Point, moving east at 10 knots.

  HAZARD...Waterspouts, wind gusts 34 knots or greater, and small 
           hail.

  SOURCE...Radar.

  IMPACT...Waterspouts can easily overturn boats and create locally 
           hazardous seas. Small craft could be damaged in briefly 
           higher winds and suddenly higher waves.

* Locations impacted include...
  Lauderdale-By-The-Sea, Deerfield Beach, Port Everglades, Fort
  Lauderdale, Lighthouse Point, Boca Raton, Highland Beach, Sea Ranch
  Lakes, Pompano Beach, Hillsboro Beach, Delray Beach and Hollywood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

Report severe weather to the Coast Guard or the National Weather
Service. You can also share your report with NWS Miami on Facebook
and Twitter.

&&

LAT...LON 2627 7985 2608 7987 2605 8016 2618 8017
      2640 8014 2653 7992
TIME...MOT...LOC 2200Z 250DEG 11KT 2628 8006 

WATERSPOUT...POSSIBLE
HAIL...<.75IN
WIND...>34KTS

$$

SPM
2 follow-up statements
065 
FZUS72 KMFL 012231
MWSMFL

Marine Weather Statement
National Weather Service Miami FL
631 PM EDT Wed Sep 1 2021

AMZ650-651-012300-
/O.CON.KMFL.MA.W.0430.000000T0000Z-210901T2300Z/
631 PM EDT Wed Sep 1 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 700 PM EDT...

For the following areas...
Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM...
Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM...

At 631 PM EDT, a severe thunderstorm capable of producing waterspouts
was located near Hillsboro Beach, or 7 nm east of Lighthouse Point,
moving east at 10 knots.

HAZARD...Waterspouts, wind gusts 34 knots or greater, and small 
         hail.

SOURCE...Radar indicated.

IMPACT...Waterspouts can easily overturn boats and create locally 
         hazardous seas. Small craft could be damaged in briefly 
         higher winds and suddenly higher waves.

Locations impacted include...
Highland Beach, Boca Raton, Delray Beach and Deerfield Beach. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

Report severe weather to the Coast Guard or the National Weather
Service. You can also share your report with NWS Miami on Facebook
and Twitter.

&&

LAT...LON 2627 7985 2618 7986 2613 7987 2610 7997
      2618 8004 2642 8011 2653 7992
TIME...MOT...LOC 2231Z 250DEG 11KT 2631 7996 

WATERSPOUT...POSSIBLE
HAIL...<.75IN
WIND...>34KTS

$$

SPM
703 
FZUS72 KMFL 012248
MWSMFL

Marine Weather Statement
National Weather Service Miami FL
648 PM EDT Wed Sep 1 2021

AMZ650-651-012258-
/O.CAN.KMFL.MA.W.0430.000000T0000Z-210901T2300Z/
648 PM EDT Wed Sep 1 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were... 
Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM...
Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM...

The thunderstorm has moved out of the area and no longer poses a
significant threat to boaters.

LAT...LON 2627 7985 2618 7986 2613 7987 2610 7997
      2618 8004 2642 8011 2653 7992
TIME...MOT...LOC 2247Z 250DEG 11KT 2633 7990 

$$

SPM

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 5:07 PM EDTSpecial Weather StatementMFLBroward23 min
Sep 1, 5:35 PM EDTSpecial Weather StatementMFLBroward25 min
Sep 1, 5:36 PM EDTSpecial Weather StatementMFLMiami-Dade24 min
Sep 1, 6:00 PM EDTSpecial Weather StatementMFLBroward30 min
Sep 1, 6:01 PM EDTSpecial Marine WarningMFL44 min
Sep 1, 6:07 PM EDTSpecial Marine WarningMFL31 min
Sep 1, 6:19 PM EDTSpecial Marine WarningMFL26 min
Sep 1, 6:29 PM EDTSpecial Marine WarningMFL28 min
Sep 1, 6:51 PM EDTSpecial Marine WarningMFL25 min
Sep 1, 6:53 PM EDTSpecial Weather StatementMFLMiami-Dade37 min
Sep 1, 6:58 PM EDTSpecial Marine WarningMFL47 min

Nearby

Special Marine Warnings in Florida, 2021Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.