Monday, September 16, 2024

Potential Tropical Cyclone Eight Prompts Tropical Storm Warning for Carolina Coast



 

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Potential Tropical Cyclone Eight Intermediate Advisory Number 3A

NWS National Hurricane Center Miami FL       AL082024

800 AM EDT Mon Sep 16 2024


...STRONG WINDS AND HEAVY RAINS SPREADING ONSHORE ACROSS PORTIONS 

OF SOUTHEASTERN NORTH CAROLINA...



SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION

----------------------------------------------

LOCATION...32.7N 78.2W

ABOUT 85 MI...140 KM S OF CAPE FEAR NORTH CAROLINA

ABOUT 100 MI...160 KM E OF CHARLESTON SOUTH CAROLINA

MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H

PRESENT MOVEMENT...NW OR 325 DEGREES AT 3 MPH...6 KM/H

MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES



WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:


None.


SUMMARY OF WATCHES AND WARNINGS IN EFFECT:


A Tropical Storm Warning is in effect for...

* Edisto Beach, South Carolina northward to Ocracoke Inlet, North

Carolina


A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area, in this case within the

next 12 hours.


For storm information specific to your area, including possible

inland watches and warnings, please monitor products issued by your

local National Weather Service forecast office.



DISCUSSION AND OUTLOOK

----------------------

At 800 AM EDT (1200 UTC), the disturbance was centered near latitude 

32.7 North, longitude 78.2 West. The system is moving toward the 

northwest near 3 mph (6 km/h). A faster motion toward the northwest 

or north-northwest is expected today and Tuesday, followed by a 

gradual turn toward the north by Wednesday. On the forecast track, 

the low will reach the coast of South Carolina this afternoon and 

then move inland across the Carolinas tonight through Wednesday.


Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. 

Little change in strength is expected before the system reaches the 

coast, and the low still has a chance of becoming a tropical or 

subtropical storm. Weakening is forecast after the system moves 

inland, and it is likely to dissipate over the Carolinas by late 

Wednesday.

* Formation chance through 48 hours...medium...60 percent.

* Formation chance through 7 days...medium...60 percent.


Tropical-storm-force winds extend outward up to 175 miles (280 km) 

from the center. Doppler radar data and surface observations 

indicate strong winds are nearing the coast and will spread onshore 

during the next few hours. NOAA buoy 41013 at Frying Pan Shoals, 

North Carolina recently reported a sustained wind of 47 mph (76 

km/h) and a gust of 56 mph (91 km/h). NOAA buoy 41037 offshore of 

Wrightsville Beach, North Carolina recently reported a sustained 

wind of 38 mph (61 km/h) and a gust of 54 mph (87 km/h).


The estimated minimum central pressure is 1005 mb (29.68 inches).



HAZARDS AFFECTING LAND

----------------------

Key messages for Potential Tropical Cyclone Eight can be found in

the Tropical Cyclone Discussion under AWIPS header MIATCDAT3 and WMO

header WTNT43 KNHC.


WIND:  Tropical storm conditions are expected within the warning

area through late this afternoon or evening.


STORM SURGE:  The combination of a storm surge and the tide will

cause normally dry areas near the coast to be flooded by rising

waters moving inland from the shoreline.  The water could reach the

following heights above ground somewhere in the indicated areas if

the peak surge occurs at the time of high tide...


South Santee River, SC to Oregon Inlet, NC... 1-3 ft

Neuse and Bay Rivers, NC... 1-3 ft

Pamlico and Pungo Rivers, NC... 1-3 ft


The deepest water will occur along the immediate coast near and to

the east of the landfall location, where the surge will be

accompanied by large and dangerous waves.  Surge-related flooding

depends on the relative timing of the surge and the tidal cycle, and

can vary greatly over short distances.  For information specific to

your area, please see products issued by your local National Weather

Service forecast office.


For a complete depiction of areas at risk of storm surge

inundation, please see the National Weather Service Peak

Storm Surge Graphic, available at

hurricanes.gov/graphics_at3.shtml?peakSurge.


RAINFALL: Potential Tropical Cyclone Eight will bring 4 to 8 inches

of rainfall, with isolated totals near 10 inches, across portions of

northeast South Carolina into southeast North Carolina today into

tonight. Across the remainder of North Carolina, 2 to 4 inches of

rainfall, with isolated totals near 6 inches, are expected through

Tuesday. Over much of Virginia, 1 to 3 inches of rainfall, with

locally higher amounts, are expected tonight through Wednesday.

This rainfall could lead to a risk of flash and urban flooding and

minor river flooding.


For a complete depiction of forecast rainfall associated with

Potential Tropical Cyclone Eight, please see the National Weather

Service Storm Total Rainfall Graphic, available at

hurricanes.gov/graphics_at3.shtml?rainqpf and the Flash Flood Risk

graphic at hurricanes.gov/graphics_at3.shtml?ero.


TORNADOES:  A couple of tornadoes may occur through this evening

across the eastern Carolinas.


SURF: Swells are forecast to affect portions of the coast of the

southeastern United States during the next couple of days. These

swells are likely to cause life-threatening surf and rip current

conditions.  Please consult products from your local weather office.



NEXT ADVISORY

-------------

Next complete advisory at 1100 AM EDT.


$$

Forecaster Reinhart


NNNN


830 

WTNT43 KNHC 160845

TCDAT3


Potential Tropical Cyclone Eight Discussion Number   3

NWS National Hurricane Center Miami FL       AL082024

500 AM EDT Mon Sep 16 2024


The structure of the area of low pressure off the coast of South

Carolina has seemingly become less organized during the past few

hours.  Proxy-visible satellite imagery indicates that the

low-level circulation is elongated from northeast to southwest, and

the center has not become well defined.  The associated deep

convection has a generally linear orientation and has been

displaced farther to the north and east of the center due to strong

upper-level winds.  Lastly, an Air Force Reserve Hurricane Hunter

aircraft still measured a 2-3 degree Celsius temperature difference

at 850 mb from north to south, indicating that the frontal boundary

is diffuse but not totally gone.  Therefore, the low is still not a

tropical or subtropical cyclone.  That said, the plane measured a 

peak wind of 54 kt at 6000 ft in the convection well northeast of 

the center, suggesting that the current intensity is about 45 kt.


The low is drifting northwestward (325 degrees) at 3 kt, gradually

approaching the South Carolina coast.  A faster motion toward the

northwest is expected to occur today as the low moves between

mid-level high pressure over the northeastern U.S. and a trough

over the southeastern U.S.  The NHC track forecast shows the low 

crossing the coast later this afternoon, which is shown by most of 

the track models.  The GFS remains the notable outlier since it 

initialized the low too far to the northwest and consequently has 

it crossing the coast around sunrise.  After moving inland, the low 

is expected to continue moving slowly northwestward and then 

northward over the Carolinas through Wednesday.  The new track 

forecast has been nudged westward from the previous forecast, 

although there is a modest amount of uncertainty given the 

ill-defined nature of the center.


The chances of the system becoming a tropical or subtropical

cyclone may be starting to decrease given the current structure, and

since it only has another 12 hours or so before moving inland.  

Most of the intensity guidance also suggests that the maximum winds 

should gradually decrease as the low approaches the coast, although 

tropical-storm-force winds are still expected to occur within the 

warning areas today.  Further weakening is forecast after the 

system moves inland, and it will likely dissipate over the Carolinas 

by late Wednesday.



Key Messages:


1. Tropical storm conditions are expected along portions of the

coasts of South Carolina and North Carolina within the Tropical

Storm Warning area through this evening.


2. The system will bring the potential for locally considerable 

flash and urban flooding and minor river flooding across southeast 

North Carolina and northeast South Carolina through tonight.  There 

is also a risk of isolated flash and urban flooding across much of 

the Mid-Atlantic region through Wednesday.


3. Coastal flooding and high surf are likely along portions of 

the southeastern U.S. coast over the next day or two.



FORECAST POSITIONS AND MAX WINDS


INIT  16/0900Z 32.4N  78.3W   45 KT  50 MPH...POTENTIAL TROP CYCLONE

 12H  16/1800Z 33.0N  79.0W   40 KT  45 MPH...TROPICAL CYCLONE

 24H  17/0600Z 33.7N  79.8W   30 KT  35 MPH...INLAND

 36H  17/1800Z 34.5N  80.6W   20 KT  25 MPH...POST-TROP/REMNT LOW

 48H  18/0600Z 35.2N  81.0W   15 KT  15 MPH...POST-TROP/REMNT LOW

 60H  18/1800Z 35.7N  81.1W   15 KT  15 MPH...POST-TROP/REMNT LOW

 72H  19/0600Z...DISSIPATED


$$

Forecaster Berg


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