Alert archive / North Carolina / Special Marine Warnings in 2021

Special Marine Warning 21, NWS Wilmington, NC

May 3, 2021

NWS Wilmington, NC issued this special marine warning at May 3, 2021, 7:32 PM EDT. It was in force for 28 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: May 3, 2021, 7:32 PM EDT (23:32 UTC)
Expired: May 3, 2021, 8:00 PM EDT
In force: 28 min
Issued by: NWS Wilmington, NC
Area: Storm-based polygon
Hail: 0.75 in
Wind: 34.0 mph

The radar

The Wilmington radar (KLTX), 63 km from the middle of the area, began a volume at 23:34 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

Charleston AFB, SC (KCHS), launched 12:00Z, 11.5 hours before the alert went out and 127 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: 1333 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 765 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 141 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 5.0

Open this sounding in Storm Lab

The text

As transmitted.

138 
WHUS52 KILM 032332
SMWILM
AMZ254-256-040000-
/O.NEW.KILM.MA.W.0021.210503T2332Z-210504T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Wilmington NC
732 PM EDT Mon May 3 2021

The National Weather Service in Wilmington has issued a

* Special Marine Warning for...
  Coastal waters from Little River Inlet to Murrells Inlet SC out 20
  nm...
  Coastal waters from Murrells Inlet to South Santee River SC out 20
  nm...

* Until 800 PM EDT.

* At 732 PM EDT, a strong thunderstorm was located over Garden City,
  moving east at 40 knots.

  HAZARD...Wind gusts 34 knots or greater and small hail.

  SOURCE...Radar.

  IMPACT...Small craft could be damaged in briefly higher winds and 
           suddenly higher waves.

* Locations impacted include...
  Murrells Inlet Sea Buoy, Myrtle Beach Rock, Belky Bear, Springmaid
  Pier, Paradise Reef, Surfside Beach and Garden City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

Frequent lightning is occurring with this storm. If caught on the
open water stay below deck if possible, keep away from ungrounded
metal objects.

&&

LAT...LON 3354 7903 3357 7901 3363 7895 3369 7888
      3368 7856 3341 7862 3349 7907
TIME...MOT...LOC 2332Z 273DEG 39KT 3360 7901 

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

$$

VAO

1 follow-up statement

582 
FZUS72 KILM 032356
MWSILM

Marine Weather Statement
National Weather Service Wilmington NC
756 PM EDT Mon May 3 2021

AMZ254-256-040006-
/O.EXP.KILM.MA.W.0021.000000T0000Z-210504T0000Z/
756 PM EDT Mon May 3 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 800 PM EDT...

The affected areas were... 
Coastal waters from Little River Inlet to Murrells Inlet SC out 20
nm...
Coastal waters from Murrells Inlet to South Santee River SC out 20
nm...

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

LAT...LON 3354 7903 3357 7901 3363 7895 3369 7888
      3368 7856 3341 7862 3349 7907
TIME...MOT...LOC 2356Z 273DEG 39KT 3359 7871 

$$

VAO

The office that day

Everything else NWS Wilmington, NC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 12:53 PM EDT	Special Weather Statement	ILM	Bladen	52 min
May 3, 1:27 PM EDT	Special Weather Statement	ILM	Brunswick	33 min
May 3, 6:26 PM EDT	Severe Thunderstorm Warning	ILM	Columbus	49 min
May 3, 6:59 PM EDT	Special Marine Warning	ILM		31 min
May 3, 7:09 PM EDT	Special Weather Statement	ILM	Brunswick	51 min
May 3, 7:30 PM EDT	Special Marine Warning	ILM		30 min
May 3, 7:59 PM EDT	Beach Hazards Statement	ILM	New Hanover, Pender	24 hr
May 3, 4:45 PM EDT	Severe Thunderstorm Warning	ILM	Darlington, Florence	60 min
May 3, 5:23 PM EDT	Special Weather Statement	ILM	Dillon	37 min
May 3, 5:25 PM EDT	Severe Thunderstorm Warning	ILM	Florence, Williamsburg	21 min
May 3, 5:42 PM EDT	Special Weather Statement	ILM	Marion	63 min
May 3, 5:44 PM EDT	Special Weather Statement	ILM	Williamsburg	31 min
May 3, 5:50 PM EDT	Severe Thunderstorm Warning	ILM	Horry, Marion	40 min
May 3, 6:13 PM EDT	Severe Thunderstorm Warning	ILM	Georgetown, Horry, Marion, Williamsburg	32 min
May 3, 6:43 PM EDT	Severe Thunderstorm Warning	ILM	Horry	32 min
May 3, 6:55 PM EDT	Special Weather Statement	ILM	Georgetown	65 min
May 3, 7:28 PM EDT	Special Weather Statement	ILM	Georgetown	32 min

Nearby

Special Marine Warnings in North Carolina, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.