Thread by @davidhelms570

1/ I'm supporting @exit266 documenting the Black Sea Grain Initiative #BSGI #BlackSeaGrainInitiative providing marine wx impacting transit & inspection operations. This🧵is a bit off-topic, analyzing weather impact on @CarnivalCruise Sunshine cruise, 21-27 May 2023.

2/ On the evening of 26 May 2023 through mid-day 27 May 2023, the @CarnivalCruise ship #Sunshine experienced high winds and waves on its final leg of 21-27 May 2023 cruise from Charleston, South Carolina to The Bahamas Islands. Cite: @flyerscaptain @CrewCenter @CruiseHive @CNN

3/ First... some terms and definitions for the landlubbers

4/ Background on the @CarnivalCruise ship #Sunshine... she's a BIG cruise ship, >100,000 tonnes, 893 ft long, able to carry 3,000 passengers, 1,150 crew.
en.wikipedia.org/wiki/Carnival_…

5/ #Sunshine currently operates out of Charleston, South Carolina, typically making weekly cruises to The Bahamas as was the case 21-27 May 2023 when #Sunshine encountered significant weather on her return home.
cruisemapper.com/ships/Carnival…

6/ @NHC_Atlantic first message indicating deteriorating conditions was issued on 24 May 2023. While National Hurricane Center didn't expect the weather system to be "tropical", low pressure systems with gale and storm force winds can be very dangerous.

https://twitter.com/NHC_Atlantic/status/1661434854914023424

7/ @NWSOPC 48 hour forecast, issued 25 May 2023 at 5:25 UTC (mid-point of #Sunshine's cruise), predicted 5 meter (18 feet) significant wave height (very substantial waves!), for 27 May 2023 00:00 UTC. exactly when #Sunshine would be steaming back to Charleston.

8/ @NHC_TAFB tweeted Friday morning (26 May) model guidance showing Storm force winds (>=48 kts) along the US southeast coast, by this time #Sunshine starting her final leg sailing home from Half Moon Cat, The Bahamas (planned ship track provided).

https://twitter.com/NHC_TAFB/status/1662091269735321601

9/ Also on the morning of 26 May 2023, @NWSOPC issued a 24 hour forecast for western Atlantic Ocean, valid 27 May 2023 at 00:00 UTC indicating "Storm" force winds (>=48kts) and sea to 24 feet (7 meters). Despite predicted poor marine conditions, #Sunshine pressed on.

10/ Here are @NWSOPC "High Seas Forecast" text bulletins send to mariners for the 24 hours leading up to #Sunshine's cruise back to Charleston.
nhc.noaa.gov/archive/text/H…

11/ So what happened, weatherwise?
27 May 2023 06:00 UTC @NWSOPC wind and wave analysis shows a 1005 mb "Storm" (>=48kts) with significant wave heights peaking at 24 ft (7.3 meters).
ncei.noaa.gov/data/ncep-char…

12/ So what happened, weatherwise?
@databuoycenter BUOY #41004 (41 NW southeast of Charleston, SC) observed winds from north-northeast 39 kts gusting to 51 kts with significant wave height to 18 ft (5.5 meters) concurrent with #Sunshine's transit.
cormp.org/graph.php?para…

13/ So what happened, weatherwise?
@esa #METOP #ASCAT winds, 27 May 2023 at 1:51 UTC pass, indicated a broad area of >=40 kts winds.

14/ So what happened, weatherwise?
@NOAASatellites #GOESEast satellite shows an intense low with thunderstorms just south of Charleston (#Sunshine's destination). IMPORTANT: WORST conditions are not at low's center, but north and northeast of the low.
col.st/nV8Ka

15/ So what did the #Sunshine's captain do in the face of significant predicted and observed marine conditions? #Sunshine actual track diverted from plan with the ship twice turning windward (into the wind) and decreasing forward speed.
cruisemapper.com/?imo=9070058

16/ What did #Sunshine's captain tell the passengers?
According to @CruiseHive, not that much. Perhaps the captain was busy trying to keep his ship safe under challenging conditions which caused limited communications with passengers? IDK
cruisehive.com/carnival-ship-…

17/ Hindsight Assessment: #Sunshine's captain was reacting to conditions as his ship entered the most intense wind region northeast of the low pressure system. #Sunshine's maneuvers exposed passengers to several additional hours of high wind and seas.

https://twitter.com/flyerscaptain/status/1662994928408854532?s=20

18/ Hindsight Assessment: #Sunshine's maneuvers, twice turning into the wind, MIGHT be explained by the captain trying to minimize exposure #Sunshine's starboard (right) side to extreme roll caused by 50 kts wind gusts and +7 meter waves.

19/ Impact reports from social media:
"Sharon Tutrone, who is a professor at Coastal Carolina University, said she went about 12 hours without an update from the captain or crew with no wi-fi or cellphone service to know what was going on."
wpde.com/news/local/car…

20/ Impact reports from social media: @CrewCenter

https://twitter.com/CrewCenter/status/1662764492118282241?s=20

21/ Impact reports from social media: @bethhart1017

https://twitter.com/bethhart1017/status/1663208014441054211?s=20

22/ Impact reports from social media: @Key2Eternity

https://twitter.com/Key2Eternity/status/1663245465104547857?s=20

23/ Impact reports from social media: @pdamron23

https://twitter.com/pdamron23/status/1663260419262169102?s=20

24/ Impact reports from social media: @WowTerrifying credit TT: k8lyns_m

https://twitter.com/WowTerrifying/status/1663328723657949185?s=20

25/ A thank you to the dedicated professionals at @NWSOPC @NHC_TAFB @NHC_Atlantic @ChrisLandsea who work 24x7 to safeguard our marine transportation system by providing forecasts and expert advice to mariners! Please follow for authoritative and timely marine warnings. /end

@NWSOPC @NHC_TAFB @NHC_Atlantic @ChrisLandsea @threadreaderapp unroll