Alert archive / Florida / Special Marine Warnings in 2021

Special Marine Warning 21, NWS Tallahassee, FL

January 31, 2021

NWS Tallahassee, FL issued this special marine warning at Jan 31, 2021, 11:28 AM EST. It was in force for 107 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
Jan 31, 2021, 11:28 AM EST (16:28 UTC)
Expired
Jan 31, 2021, 1:15 PM EST
In force
107 min
Issued by
NWS Tallahassee, FL
Area
Storm-based polygon
Hail
0.0 in
Wind
34.0 mph

The radar

The Tallahassee radar (KTLH), 62 km from the middle of the area, began a volume at 16:29 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 4.5 hours before the alert went out and 62 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, Tallahassee Rgnl, FL at 12:00Z on 2021-01-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Tallahassee Rgnl, FL at 12:00Z on 2021-01-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 493 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
924 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
493 m²/s²
0-3 km storm-relative helicity
546 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

513 
WHUS52 KTAE 311628
SMWTAE
GMZ730-755-765-775-311930-
/O.NEW.KTAE.MA.W.0021.210131T1628Z-210131T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Tallahassee FL
1128 AM EST Sun Jan 31 2021

The National Weather Service in Tallahassee has issued a

* Special Marine Warning for...
  Apalachee Bay or Coastal Waters From Keaton Beach to Ochlockonee
  River Fl out to 20 Nm...
  Coastal Waters From  Ochlockonee River to Apalachicola FL out to 20
  Nm...
  Coastal waters from  Suwannee River to Keaton Beach out 20 NM...
  Waters from Suwannee River to Apalachicola FL from 20 to 60 NM...

* Until 230 PM EST.

* At 1127 AM EST, showers with gusty winds were located along a line 
  extending from 7 nm southeast of St. Marks to 7 nm northwest of C 
  Tower, moving east at 25 knots.

  HAZARD...Wind gusts 34 knots or greater.

  SOURCE...Radar indicated.

  IMPACT...Expect wind gusts in excess of 34 knots...suddenly higher 
           waves...and heavy downpours. Make sure all on board are 
           wearing life jackets.

* Locations impacted include...
  Buckeye Reef, O Tower, C Tower, K Tower and Marker 24 Barge. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek safe shelter, mariners can expect gusty winds and increasing
waves.

&&

LAT...LON 3004 8383 3004 8375 2984 8354 2952 8401
      2930 8485 2940 8498 2953 8498 2993 8455
      2996 8449 3013 8433 3013 8410 3016 8399
TIME...MOT...LOC 1627Z 263DEG 24KT 3005 8415 2952 8493 

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

$$

42-DVD
1 follow-up statement
350 
FZUS72 KTAE 311815
MWSTAE

Marine Weather Statement
National Weather Service Tallahassee FL
115 PM EST Sun Jan 31 2021

GMZ730-755-765-775-311825-
/O.CAN.KTAE.MA.W.0021.000000T0000Z-210131T1930Z/
115 PM EST Sun Jan 31 2021

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

The affected areas were... 
Apalachee Bay or Coastal Waters From Keaton Beach to Ochlockonee
River Fl out to 20 Nm...
Coastal Waters From  Ochlockonee River to Apalachicola FL out to 20
Nm...
Coastal waters from  Suwannee River to Keaton Beach out 20 NM...
Waters from Suwannee River to Apalachicola FL from 20 to 60 NM...

The showers have weakened and no longer pose a significant threat to
boaters.

LAT...LON 3004 8383 3004 8375 2984 8354 2952 8401
      2930 8485 2940 8498 2953 8498 2993 8455
      2996 8449 3013 8433 3013 8410 3016 8399
TIME...MOT...LOC 1814Z 263DEG 24KT 3013 8333 2961 8411 

$$

42-DVD

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 31, 8:31 AM ESTSpecial Marine WarningTAE3 hr
Jan 31, 5:38 PM ESTSpecial Weather StatementTAECook, Lanier52 min
Jan 31, 6:25 PM ESTSpecial Weather StatementTAELanier50 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.