TS Ophelia

[Normandy]

While there euro and GFS disagree on intensity, one thing they do agree on is the likelihood of an enhanced wind jet north of the center spreading into the mid Atlantic.  Two things I’m watching: how quickly it organizes before approaching the coast and how far east does the low track.

[GaWx]

 Here was the 0Z UKMET (12Z is further down in this post):
 

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 66 HOURS
FORECAST POSITION AT T+ 66 : 32.2N 76.5W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 23.09.2023 72 34.2N 75.6W 1004 43
1200UTC 23.09.2023 84 36.3N 75.0W 1001 48
0000UTC 24.09.2023 96 39.1N 73.1W 998 42
1200UTC 24.09.2023 108 42.1N 69.4W 998 39
0000UTC 25.09.2023 120 45.5N 64.0W 995 41
1200UTC 25.09.2023 132 46.8N 63.5W 993 45
0000UTC 26.09.2023 144 46.3N 60.6W 999 41
1200UTC 26.09.2023 156 45.9N 55.9W 1005 29
0000UTC 27.09.2023 168 CEASED TRACKING
 

  

12Z UKMET is back to being more offshore with a TC:

 NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER  72 HOURS
              FORECAST POSITION AT T+ 72 : 35.5N  74.1W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    1200UTC 23.09.2023   72  35.5N  74.1W     1006            42
    0000UTC 24.09.2023   84  37.7N  72.3W     1003            38
    1200UTC 24.09.2023   96  40.9N  67.9W     1004            34
    0000UTC 25.09.2023  108  43.6N  62.1W     1004            36
    1200UTC 25.09.2023  120  43.9N  58.3W     1004            39
    0000UTC 26.09.2023  132              CEASED TRACKING

[Ed, snow and hurricane fan]

Quote

2. Western Atlantic:
A non-tropical low pressure system is expected to form within a 
large area of disorganized showers and thunderstorms to the east 
of the Florida peninsula within the next day or two.  This system 
could acquire some subtropical characteristics on Friday while it 
moves generally northward.  Regardless of development, this low is 
likely to bring gusty winds to gale force, heavy rain, and high surf 
to portions of the Southeast and Mid-Atlantic United States late 
this week and into this weekend.  Additional information on this 
system can be found in High Seas Forecasts and products from your 
local National Weather Service office.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...40 percent.

40% orange.

[NorthHillsWx]

Im sure others saw but 12z GFS brought a borderline hurricane into cape lookout

[StantonParkHoya]

10 minutes ago, NorthHillsWx said:

Im sure others saw but 12z GFS brought a borderline hurricane into cape lookout

It’s not tropical

[Ed, snow and hurricane fan]

2 minutes ago, StantonParkHoya said:

It’s not tropical

Does that matter in the bigger picture?  Edit to Add Image in Addition to Y Cantor tweet:  Its subtropical

 

[PackGrad05]

The 18Z 3K NAM has gusts of 50-60 over central NC Saturday morning.  

[MattPetrulli]

18z euro takes a step towards GFS

[GaWx]

0Z UKMET: becomes a TC 36 hours earlier vs 12Z run; back on the coast NC to NJ

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER  24 HOURS
              FORECAST POSITION AT T+ 24 : 30.4N  74.8W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    0000UTC 22.09.2023   24  30.4N  74.8W     1007            38
    1200UTC 22.09.2023   36  32.4N  75.0W     1004            44
    0000UTC 23.09.2023   48  33.4N  75.9W      997            45
    1200UTC 23.09.2023   60  35.4N  76.0W      995            43
    0000UTC 24.09.2023   72  37.8N  75.7W      994            40
    1200UTC 24.09.2023   84  39.1N  74.6W     1001            32
    0000UTC 25.09.2023   96  39.9N  73.5W     1007            33
    1200UTC 25.09.2023  108  40.0N  72.2W     1009            34
    0000UTC 26.09.2023  120  39.5N  69.6W     1011            34
    1200UTC 26.09.2023  132              CEASED TRACKING

[GaWx]

0Z Euro at 48: strongest run yet at 997 mb 150 mi SE of Wilmington, NC

[shaggy]

4 hours ago, GaWx said:

0Z Euro at 48: strongest run yet at 997 mb 150 mi SE of Wilmington, NC

Seems to be 2 camps. Hi res models are much stronger and show a stronger capture with the west turn before releasing it north. All show a potential hurricane. Globals don't show as much of a capture or as strong of a system 

[NorthHillsWx]

Everything has trended towards a stronger, more tropical system since this time yesterday. Euro has jumped into GFS camp 

[WxWatcher007]

59 minutes ago, NorthHillsWx said:

Everything has trended towards a stronger, more tropical system since this time yesterday. Euro has jumped into GFS camp 

Yeah you could tell yesterday that the trend was upward. Once a low develops, it starts to intensify fairly quickly for how little time it has over water. I still think subtropical, but honesty if those model depictions verify it looks like it could become tropical right before landfall. 

8am

1. Western Atlantic:
A trough of low pressure located several hundred miles east of the 
Florida peninsula is producing a large area of disorganized showers 
and thunderstorms. A non-tropical low pressure system is expected 
to form within this area by early Friday, and this system could 
acquire some subtropical characteristics on Friday or early Saturday 
while it moves generally northward toward the coast of North 
Carolina. Regardless of subtropical development, this low is likely 
to bring gusty winds to gale force, heavy rain, and high surf to 
portions of the Southeast and Mid-Atlantic United States on Friday 
and into the weekend. Additional information on this system, 
including storm and gale warnings, can be found in High Seas 
Forecasts and products from your local National Weather Service 
office.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...medium...40 percent.

[NorthHillsWx]

1 hour ago, WxWatcher007 said:

Yeah you could tell yesterday that the trend was upward. Once a low develops, it starts to intensify fairly quickly for how little time it has over water. I still think subtropical, but honesty if those model depictions verify it looks like it could become tropical right before landfall. 

 

Not that this will be strong enough to cause that many problems, but I do worry lack of lead up prep time will catch some people off guard especially if it comes in as a high-end TS. We have a 45 boat sitting in an in-water slip in. wanchese NC. We are going to head down tonight to secure it. Thankfully with the full moon a week away tides won’t be too severe but this seems like a 2-4 ft water rise for places in the sound, regardless of tropical classification 

[mob1]

06Z Euro has a deeper storm now 

[olafminesaw]

51 minutes ago, mob1 said:

06Z Euro has a deeper storm now 

Also moving more due N rather than NE, as depicted by the GFS, at landfall. Indicates more impact further inland. I think I95 East is a near lock for a moderate impact event. And between Raleigh and I95 is still up in the air depending on track. The Western piedmont should be relatively low impact as of now

[shaggy]

4 minutes ago, olafminesaw said:

Also moving more due N rather than NE, as depicted by the GFS, at landfall. Indicates more impact further inland. I think I95 East is a near lock for a moderate impact event. And between Raleigh and I95 is still up in the air depending on track. The Western piedmont should be relatively low impact as of now

Hi res are all more cape fear to lookout globals more over bogue banks to obx

[GaWx]

29 minutes ago, shaggy said:

Hi res are all more cape fear to lookout globals more over bogue banks to obx

Whereas 0Z UKMET was 994 mb near Ocracoke, the 6Z UKMET is 992 mb (strongest run yet) ~50 miles further W near Cape Lookout at 5AM EDT Saturday 9/23 and then moves N to 50 miles W of VA Beach at 2PM EDT:
 

[WxWatcher007]

Now designated as Invest 99L. 

[NorthHillsWx]

I’m beginning to think this one might become quite interesting for us NC folks

[PackGrad05]

2 minutes ago, NorthHillsWx said:

I’m beginning to think this one might become quite interesting for us NC folks

What's ironic is that it will have more of an impact that then remnants of the one a few weeks ago.  The difference it that it doesn't come with all the "hype" that the other one did.

[NorthHillsWx]

Quite a few members of both EPS and GEFS suites get this below 990 mb before coming ashore. While it’s of non tropical origin and winds will likely be lower as compared to a tropical cyclone at equal pressure, I do not think a storm near hurricane force is off the table. For folks on the coast that’s what I’d prepare for. 

[olafminesaw]

34 minutes ago, WxWatcher007 said:

Now designated as Invest 99L. 

It will be nice to get the hurricane models in on the action as well

[Random Chaos]

ASCAT pass from about 4 hours ago:

 

[WxWatcher007]

Special Tropical Weather Outlook...Corrected
NWS National Hurricane Center Miami FL
1000 AM EDT Thu Sep 21 2023

Corrrected time in the product

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Special outlook issued to raise probabilities and update discussion 

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane 
Nigel, located over the central subtropical Atlantic.

Off the Southeastern United States Coast (AL99):
Updated...A trough of low pressure located several hundred miles 
east of the Florida peninsula continues to produce a large area of 
disorganized showers and thunderstorms. A non-tropical low pressure 
system is expected to form within this area by early Friday, and 
there are increasing chances that this system could acquire some 
tropical or subtropical characteristics on Friday or early Saturday 
while it moves generally northward toward the coast of North 
Carolina. Regardless of tropical or subtropical development, this 
low is likely to bring tropical storm force winds, heavy rain, 
coastal flooding, and high surf to portions of the southeast and 
mid-Atlantic United States coastline on Friday and into the 
weekend. Tropical Storm watches or warnings could be required for 
this system as soon as later this morning. Additional information on 
this system, including storm and gale warnings, can be found in High 
Seas Forecasts and products from your local National Weather Service 
office.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 7 days...medium...50 percent.

[marsman]

NHC will initiate advisories on Potential Tropical Cyclone Sixteen, located offshore of the southeast coast of the United States, at 1100 AM EDT (1500 UTC).

[NorthHillsWx]

Cape Fear just got NAM’d

[3dcg]

interesting little swirl exposed - well, hello!

https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=eus&band=GEOCOLOR&length=24

[GaWx]

 This is now PTC 16: 

Potential Tropical Cyclone Sixteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL162023
1100 AM EDT Thu Sep 21 2023

A broad non-tropical area of low pressure has formed well east of 
the east coast of Florida this morning.  Although this system is 
forecast to remain non-tropical during the next 12-24 hours, the 
dynamical model guidance indicates that it will likely acquire 
tropical characteristics late Friday and early Saturday as it 
approaches the coast of North Carolina.  Although it is unclear as 
to whether the cyclone detaches from a front that is forecast to 
extend northeastward from the center, the guidance suggests a 
tropical-cyclone like core and structure when it nears the coast.  
As a result, advisories are being initiated on Potential Tropical 
Cyclone Sixteen to issue Tropical Storm Warnings and Storm Surge 
Watches for portions of the coasts of North Carolina, Virginia and 
Maryland. Winds associated with the front farther north are being 
covered by non-tropical products issued by local National Weather 
Service offices and the Ocean Prediction Center.  Additional 
tropical watches and warnings could be issued for other portions of 
the Chesapeake Bay later today. 

Since the low is still in its formative stage, the initial motion
estimate is a highly uncertain 360/8 kt.  The model guidance
suggests that center reformations are likely to occur during the
next day or so, but the overall motion of the system is expected to
be a little east of due north. As the system interacts with a 
mid-latitude trough that it becomes embedded within, a bend toward
the north-northwest is forecast.  That motion should bring the 
center over eastern North Carolina within the warning area Saturday 
morning.  The NHC track forecast follows a blend of the various 
global models that are in good agreement. 

The system is forecast to gradually strengthen during the next 24 
hours. After that time, the guidance suggests it is likely to form 
a smaller inner core with additional strengthening expected until 
the center reaches the coast.  The NHC intensity forecast follows 
the ECMWF and GFS models trends. 

Key Messages:

1. An area of low pressure is forecast to develop off the 
southeastern U.S. coast later today and will bring 
tropical-storm-force winds, storm surge, heavy rain, and high surf 
to large portions of the southeast and mid-Atlantic United States 
coast beginning Friday and continuing into the weekend. 

2. There is the potential for life-threatening storm surge 
inundation from Surf City, North Carolina to Chincoteague, Virginia, 
the Pamlico and Albemarle Sounds, and the lower Chesapeake Bay. 
Residents in these areas should follow advice given by local 
officials. 

3. Tropical storm conditions are expected within portions of the 
southeast and mid-Atlantic coasts within the Tropical Storm Warning 
area beginning on Friday and continuing into Saturday. 

4. Heavy rainfall from this system could produce localized urban 
and small stream flooding impacts across the eastern mid-Atlantic 
states from North Carolina to New Jersey Friday through Sunday.

FORECAST POSITIONS AND MAX WINDS

INIT  21/1500Z 28.7N  75.9W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  22/0000Z 30.0N  75.5W   35 KT  40 MPH...POTENTIAL TROP CYCLONE
 24H  22/1200Z 31.7N  75.4W   45 KT  50 MPH...POTENTIAL TROP CYCLONE
 36H  23/0000Z 33.2N  75.6W   50 KT  60 MPH...TROPICAL CYCLONE
 48H  23/1200Z 35.1N  76.4W   50 KT  60 MPH...TROPICAL CYCLONE
 60H  24/0000Z 37.3N  76.4W   40 KT  45 MPH...TROPICAL CYCLONE
 72H  24/1200Z 38.8N  76.1W   30 KT  35 MPH...POST-TROPICAL
 96H  25/1200Z 40.4N  71.8W   25 KT  30 MPH...POST-TROPICAL
120H  26/1200Z...DISSIPATED

$$
Forecaster Brown

[GaWx]

BULLETIN
Potential Tropical Cyclone Sixteen Advisory Number   1
NWS National Hurricane Center Miami FL       AL162023
1100 AM EDT Thu Sep 21 2023

...LOW PRESSURE AREA EXPECTED TO BRING TROPICAL STORM CONDITIONS
AND THE POTENTIAL FOR LIFE-THREATENING STORM SURGE TO PORTIONS OF
THE SOUTHEAST AND MID-ATLANTIC COASTS...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...28.7N 75.9W
ABOUT 370 MI...595 KM SE OF CHARLESTON SOUTH CAROLINA
ABOUT 450 MI...725 KM S OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

A Tropical Storm Warning has been issued from Cape Fear, North
Carolina, northward to Fenwick Island, Delaware, including
Albemarle and Pamlico Sounds, and the Chesapeake Bay south of
Smith Point.

A Storm Surge Watch has been issued from Surf City, North Carolina
to Chincoteague, Virginia, and the for the Chesapeake Bay south of
Smith Point, including Albemarle and Pamlico Sounds.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Cape Fear NC to Fenwick Island DE
* Chesapeake Bay south of Smith Point
* Albemarle and Pamlico Sounds

A Storm Surge Watch is in effect for...
* Surf City NC to Chincoteague VA
* Chesapeake Bay south of Smith Point
* Albemarle and Pamlico Sounds

DISCUSSION AND OUTLOOK
----------------------
At 1100 AM EDT (1500 UTC), the disturbance was centered near
latitude 28.7 North, longitude 75.9 West. The system is moving
toward the north near 9 mph (15 km/h), and this general motion is 
expected to continue through early Friday. A north-northwestward to 
northward motion is forecast by late Friday and continue into 
the weekend. On the forecast track, the center of the cyclone is 
expected to approach the coast of North Carolina within the warning 
area Friday night and early Saturday. 

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Strengthening is expected during the next day or two, and the system 
is forecast to become a tropical storm as it approaches the coast 
of North Carolina. Regardless of whether the system become a 
tropical storm, the system is expected to bring tropical-storm 
conditions to portions of the southeast and mid-Atlantic coast. 
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...medium...60 percent.

The estimated minimum central pressure is 1012 mb (29.89 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for this system can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT1 and WMO header 
WTNT41 KNHC and on the web at
hurricanes.gov/text/MIATCDAT!.shtml

STORM SURGE:  The combination of a dangerous 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...

Surf City NC to Chincoteague VA...2-4 ft
Chesapeake Bay south of Smith Point...2-4 ft
Albemarle and Pamlico Sounds...2-4 ft
South Santee River SC to Surf City NC 1-3 ft
Chincoteague VA to Fenwick Island DE...1-3 ft