Alert archive / Florida / Special Weather Statements in 2021

Special Weather Statement, NWS Key West, FL

December 19, 2021

NWS Key West, FL issued this special weather statement at Dec 19, 2021, 3:35 AM EST. It was in force for 25 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: Dec 19, 2021, 3:35 AM EST (08:35 UTC)
Expired: Dec 19, 2021, 4:00 AM EST
In force: 25 min
Issued by: NWS Key West, FL
Hail: 0.00 in
Wind: 30

The radar

The Key West radar (KBYX), 55 km from the middle of the area, began a volume at 08:34 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 00:00Z, 8.6 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-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: 1278 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 844 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

693 
WWUS82 KKEY 190835
SPSKEY

Special Weather Statement
National Weather Service Key West FL
335 AM EST Sun Dec 19 2021
 
FLZ077-190900-
Monroe Middle Keys FL-
335 AM EST Sun Dec 19 2021

...A strong thunderstorm will impact portions of Middle Keys in
Monroe County through 400 AM EST...

At 334 AM EST, Doppler radar was tracking a strong thunderstorm over
Pidgeon Key, or over Seven Mile Bridge, moving north at 15 mph.

HAZARD...Winds in excess of 30 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects.

Locations impacted include...
Marathon, East End Of Seven Mile Bridge, Seven Mile Bridge, West End
Of Seven Mile Bridge, Boot Key, Knight Key and Pidgeon Key.

This includes US 1 between mile markers 40 and 51. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 2470 8124 2471 8123 2469 8121 2470 8119
      2473 8117 2475 8106 2470 8104 2467 8113
      2467 8115 2469 8118 2468 8121 2465 8122
TIME...MOT...LOC 0834Z 180DEG 15KT 2470 8116 

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

$$

Williams

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 19, 3:29 AM EST	Special Marine Warning	KEY		28 min
Dec 19, 3:57 AM EST	Special Marine Warning	KEY		48 min
Dec 19, 4:58 AM EST	Areal Flood Advisory	KEY	Monroe	3 hr

Nearby

Special Weather Statements in Florida, 2021 Every special weather statement 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.