Alert archive / Florida / Special Marine Warnings in 2021

Special Marine Warning 310, NWS Key West, FL

November 18, 2021

NWS Key West, FL issued this special marine warning at Nov 18, 2021, 11:54 AM EST. It was in force for 21 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
Nov 18, 2021, 11:54 AM EST (16:54 UTC)
Expired
Nov 18, 2021, 12:15 PM EST
In force
21 min
Issued by
NWS Key West, FL
Area
Storm-based polygon
Hail
0.0 in
Wind
34.0 mph

The radar

The Key West radar (KBYX), 70 km from the middle of the area, began a volume at 16:56 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

Key West, FL (KEYW), launched 12:00Z, 4.9 hours before the alert went out and 73 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, Key West, FL at 12:00Z on 2021-11-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1519 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Key West, FL at 12:00Z on 2021-11-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 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
1519 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
642 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
147 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

519 
WHUS52 KKEY 181654
SMWKEY
GMZ032-181715-
/O.NEW.KKEY.MA.W.0310.211118T1654Z-211118T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Key West FL
1154 AM EST Thu Nov 18 2021

The National Weather Service in Key West has issued a

* Special Marine Warning for...
  Bayside and Gulf side from Craig Key to west end of Seven Mile
  Bridge...

* Until 1215 PM EST.
		
* At 1152 AM EST, a possible waterspout was located near John Sawyer
  Bank Light, moving northwest at 15 knots.

  HAZARD...Waterspouts and wind gusts 34 knots or greater.

  SOURCE...National Weather Service Meteorologist.

  IMPACT...Waterspouts can quickly form and capsize boats, cause 
           considerable damage to vessels and create suddenly higher 
           waves. Expect wind gusts in excess of 34 knots, suddenly 
           higher waves, occasional lightning, and heavy downpours.

* The possible waterspout will remain over mainly open waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A waterspout is a tornado over water that can be dangerous and even
deadly. Small craft can be swamped or overturned by a waterspout,
avoid at all times.

&&

LAT...LON 2479 8098 2476 8106 2489 8126 2498 8104
TIME...MOT...LOC 1652Z 148DEG 16KT 2481 8106 

WATERSPOUT...POSSIBLE
HAIL...0.00IN
WIND...>34KTS

$$

NB
1 follow-up statement
835 
FZUS72 KKEY 181708
MWSKEY

Marine Weather Statement
National Weather Service Key West FL
1208 PM EST Thu Nov 18 2021

GMZ032-181718-
/O.EXP.KKEY.MA.W.0310.000000T0000Z-211118T1715Z/
1208 PM EST Thu Nov 18 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 1215 PM EST...

The affected areas were... 
Bayside and Gulf side from Craig Key to west end of Seven Mile
Bridge...

The waterspout weakened and no longer poses a significant threat to
boaters.

LAT...LON 2479 8098 2476 8106 2489 8126 2498 8104
TIME...MOT...LOC 1708Z 148DEG 16KT 2487 8110 

$$

NB

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 18, 4:24 AM ESTSmall Craft AdvisoryKEY12 hr
Nov 18, 5:28 AM ESTSpecial Marine WarningKEY62 min
Nov 18, 6:21 AM ESTSpecial Marine WarningKEY25 min
Nov 18, 6:24 AM ESTSpecial Marine WarningKEY54 min
Nov 18, 7:17 AM ESTSpecial Marine WarningKEY28 min
Nov 18, 9:24 AM ESTSpecial Marine WarningKEY40 min
Nov 18, 9:45 AM ESTSpecial Marine WarningKEY37 min
Nov 18, 9:59 AM ESTSpecial Marine WarningKEY38 min
Nov 18, 10:30 AM ESTSpecial Marine WarningKEY60 min
Nov 18, 10:59 AM ESTSpecial Marine WarningKEY61 min
Nov 18, 11:27 AM ESTSpecial Marine WarningKEY63 min
Nov 18, 12:31 PM ESTSpecial Marine WarningKEY29 min
Nov 18, 12:37 PM ESTSpecial Marine WarningKEY23 min
Nov 18, 12:55 PM ESTSpecial Marine WarningKEY65 min
Nov 18, 2:00 PM ESTSpecial Marine WarningKEY60 min
Nov 18, 2:07 PM ESTSpecial Marine WarningKEY68 min
Nov 18, 2:24 PM ESTSpecial Marine WarningKEY66 min
Nov 18, 2:45 PM ESTAreal Flood AdvisoryKEYMonroe3 hr
Nov 18, 2:46 PM ESTAreal Flood AdvisoryKEYMonroe3 hr
Nov 18, 2:56 PM ESTSpecial Marine WarningKEY34 min
Nov 18, 3:27 PM ESTSpecial Marine WarningKEY18 min
Nov 18, 3:38 PM ESTSpecial Marine WarningKEY34 min
Nov 18, 3:46 PM ESTSpecial Marine WarningKEY41 min
Nov 18, 3:48 PM ESTSpecial Marine WarningKEY39 min
Nov 18, 5:14 PM ESTSpecial Marine WarningKEY17 min
Nov 18, 5:30 PM ESTSpecial Marine WarningKEY45 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.