Tropical Storm Ophelia—Tropical Storm Warning for Coastal Mid-Atlantic

[Maestrobjwa]

So they move Artscape to September to escape the July heat...and now the first year back it gets raised on, lolol Sheesh

[WxWatcher007]

15 minutes ago, Stormfly said:

That's shocking but I know intensity forecasts seem most difficult as we've seen in the past.

The first SHIPS forecast was eye opening and I think there’s a good chance of the dynamics I posted about earlier leading to development of an inner core. Time is the limitation here, I think.

[yoda]

FWIW, 12z CMC still very wet

 

[SomeguyfromTakomaPark]

Euro is a solid 1-3 inches of rain region wide NW to SE.  The windiest panel is 18 kt sustained winds in DC.

[CAPE]

10 minutes ago, SomeguyfromTakomaPark said:

Euro is a solid 1-3 inches of rain region wide NW to SE.  The windiest panel is 18 kt sustained winds in DC.

Not as wet as the last 2 runs, especially for areas further inland.

[yoda]

BULLETIN
Potential Tropical Cyclone Sixteen Intermediate Advisory Number 1A
NWS National Hurricane Center Miami FL       AL162023
200 PM EDT Thu Sep 21 2023

...TROPICAL STORM CONDITIONS AND THE POTENTIAL FOR 
LIFE-THREATENING STORM SURGE OVER PORTIONS OF THE SOUTHEAST AND 
MID-ATLANTIC COASTS BEGINNING ON FRIDAY...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...29.0N 75.9W
ABOUT 355 MI...565 KM SE OF CHARLESTON SOUTH CAROLINA
ABOUT 430 MI...690 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

[BristowWx]

13 minutes ago, SomeguyfromTakomaPark said:

Euro is a solid 1-3 inches of rain region wide NW to SE.  The windiest panel is 18 kt sustained winds in DC.

is 18kt sustained even WA or HHW criteria?  

[yoda]

Windy wording has entered the zones... wind gusts to 40 mph in DC

Zone Forecast Product
National Weather Service Baltimore MD/Washington DC
134 PM EDT Thu Sep 21 2023

DCZ001-212100-
District of Columbia-
Including the city of Washington
134 PM EDT Thu Sep 21 2023

.THIS AFTERNOON...Partly sunny. Highs in the upper 70s. Northeast
winds around 5 mph.
.TONIGHT...Partly cloudy. Lows in the upper 50s. Northeast winds
around 5 mph.
.FRIDAY...Partly sunny in the morning, then becoming mostly
cloudy. Highs in the mid 70s. Northeast winds 10 to 15 mph.
.FRIDAY NIGHT...Cloudy. A chance of rain in the evening, then
rain likely after midnight. Lows around 60. Northeast winds 15 to
20 mph. Chance of rain 70 percent.
.SATURDAY...Rain, windy with highs in the mid 60s. North winds
20 to 30 mph with gusts up to 40 mph. Chance of rain 90 percent.
.SATURDAY NIGHT...Rain likely. Windy with lows in the upper 50s.
Chance of rain 70 percent.
.SUNDAY...Showers likely. Highs in the upper 60s. Chance of rain
60 percent.

[yoda]

Updated afternoon discussion from LWX 

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
233 PM EDT Thu Sep 21 2023

.SYNOPSIS...
High pressure will remain to the north across New England
through early Friday. An area of low pressure will approach from the
southeastern U.S. coast Friday into the upcoming weekend. The low
pressure system will exit by late Sunday with high pressure building
over the Mid-Atlantic early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
High pressure over New England will drift to just offshore of
Nova Scotia while low pressure deepens offshore of the Southeast
and heads for the Carolinas (possibly acquiring tropical/sub-
tropical characteristics - refer to hurricanes.gov for details).
This will result in an uptick in high and mid-level clouds,
seasonable temperatures, and gradually increasing easterly
breezes especially by late Friday afternoon.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A rather blocky upper-level jet pattern will be evident through
the weekend over North America, with a blocking area of high
pressure over the Canadian Maritimes. This should result in
deepening low pressure heading into the Carolinas Friday night.

To the north of this low and between the high pressure to the
north, easterly winds will increase substantially Friday night
into Saturday. The strongest winds are expected closer to and
over the Chesapeake Bay; in these areas, gusts could reach or
exceed 50 mph. Further west to and including the Blue Ridge and
Catoctin Mountains, 30 to 40 mph wind gusts will likely be more
commonplace. Breezy conditions at slightly lower speeds are
anticipated further west. The wind should persist for 12-18
hours late Friday night through Saturday night as the low
creeps in from the south. Given the persistent winds and
anticipated waves of rain, this may result in isolated wind
damage (i.e. tree/branch/power line damage).

These winds will also bring in tropical moisture and a threat
for heavy rainfall (see the Hydrology section below). Rain is
most likely in two waves: (1) with an initial moisture advection
band late Friday night into Saturday morning, and (2) with the
low itself Saturday afternoon and night.

Lingering rain and precipitation from an area of low pressure will
continue to impact the area as it dissipates overhead on Sunday.
Uncertainty continues with the specific location and timing of the
heaviest rainfall, but global model ensembles are in relatively good
agreement regarding the dissipation of the low. However,
deterministic model guidance continues to show variability from
model to model and run to run. A more eastern track of the low would
result in heaviest precipitation to be located mostly east of I-95
while a more western track would expand the area for heavy rainfall
along and west of I-95. Either way, unsettled conditions continue
throughout the day Sunday with breezy conditions expected. Wind
gusts will be highest Sunday morning before gradually dissipating
throughout the day.

[gymengineer]

I know people have pointed out issues with these gust products, but here are the "peak" panels from various 12Z model runs:

https://weather.us/model-charts/standard/maryland/gusts-1h-3h-mph/20230923-1800z.html

https://weather.us/model-charts/conus-hd/maryland/gusts-mph/20230923-1800z.html

https://weather.us/model-charts/euro/maryland/gusts-3h-mph/20230924-0300z.html

https://weather.us/model-charts/gbr/maryland/gusts-1h-3h-mph/20230924-0000z.html

https://weather.us/model-charts/can/maryland/gusts-3h-mph/20230923-2100z.html

 

[SomeguyfromTakomaPark]

17 minutes ago, BristowWx said:

is 18kt sustained even WA or HHW criteria?  

I'd guess wind advisory for this.   

[yoda]

H/t @MattPetrulli

 

 

[AlexD1990]

Record or near-record flooding now forecast along the Delaware Bay:

 

 

 

 

[stormy]

I nailed the huge shift in the ECMWF yesterday with a lucky bet.

I feel lucky again today. I therefore predict the incoming 18z NAM12  will dry somewhat for western areas.

[yoda]

Rain starts in DC just 00z SAT on 18z NAM 

Already over an inch of rain down by CHO by 09z Saturday 

[Eskimo Joe]

The latest QPF forecast from WPC as it aligns with the MARFC boundary:

 

[Deck Pic]

Maybe we should do a contest on rain totals 

[yoda]

Just now, Deck Pic said:

Maybe we should do a contest on rain totals 

Tiebreaker of highest wind gust?

[09-10 analogy]

57 minutes ago, alexderiemer said:

Record or near-record flooding now forecast along the Delaware Bay:

 

 

 

 

When were those records set? Isabel? Sandy? Or maybe Ash Wednesday if the records go back that far?

[yoda]

18z NAM is also advertising a long time period of 40 to 50 mph wind gusts for a lot of the region... 50+ at times out towards the Bay and over the mountains 

[MillvilleWx]

12 minutes ago, Eskimo Joe said:

The latest QPF forecast from WPC as it aligns with the MARFC boundary:

 

Awesome to see! National Blend came in much wetter, as expected much of the deterministic suite now favoring more impact further west, but still a sharp cutoff on the western edge towards the Appalachian front. This is well within the means of potential and before any hi-res ensemble data can be integrated to show Convective schema and more detailed max/min variance over the QPF field. 

[gymengineer]

5 minutes ago, 09-10 analogy said:

When were those records set? Isabel? Sandy? Or maybe Ash Wednesday if the records go back that far?

The record at Lewes was set by the January 2016 blizzard, which displaced the previous record from Ash Wednesday.

[Stormfly]

6 minutes ago, gymengineer said:

The record at Lewes was set by the January 2016 blizzard, which displaced the previous record from Ash Wednesday.

Lewes in High Wind Warning already!

[AlexD1990]

When were those records set? Isabel? Sandy? Or maybe Ash Wednesday if the records go back that far?

Sandy, Irene, and blizzard of 2016, if I read the info graphic correctly

Sent from my SM-F711U using Tapatalk

[stormy]

I could be vain and say I'm batting 1000............. But honesty is one of my highest attributes!

I thought the 18z12 NAM would shift east from Richmond toward consensus up the bay and the NHC track. H--- it shifted west to Lynchburg!!

But, I believed the 12z to be too juicy.......  I dropped from 4.12" to 3.02".............

Winning streak continues!   I'll practice some more before the snow flies.

[yoda]

Potential Tropical Cyclone Sixteen Discussion Number   2
NWS National Hurricane Center Miami FL       AL162023
500 PM EDT Thu Sep 21 2023

High-resolution visible satellite imagery and surface synoptic
observations indicate that the disturbance has not yet acquired a
well-defined center of circulation.  There is a distinct
comma-shaped curved band of convection over the eastern portion of
the system, with moderate southwesterly vertical wind shear over 
the area.  The current intensity is set at 30 kt based on surface 
observations.

Since there is still no distinct center the initial motion, 360/7 
kt, is an educated guess.  The dynamical model guidance suggests 
that there may be some center re-formations during the next day or 
two.  However, the system should move generally northward to 
north-northwestward over the next couple of days while embedded on 
the eastern side of a deep-layer trough over the eastern United 
States.  The official forecast is close to the previous one and is 
also close to the corrected dynamical model consensus.

Strong vertical wind shear is likely to persist over the system, 
but the global models show strengthening before landfall.  This 
intensification is probably at least partially due to baroclinic 
energy sources.  In fact the ECMWF forecast suggests that the 
system will retain at least some frontal cyclone characteristics 
through landfall.  Nonetheless, the system is likely to cause 
tropical-storm-force winds, locally heavy rainfall, and dangerous 
storm surges over the warned areas in the southeastern and 
mid-Atlantic United States.  Interests should be aware that 
hazardous conditions will extend well away from the forecast center 
locations.

Key Messages:

1. An area of low pressure is forecast to strengthen off the
southeastern U.S. coast and 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 a danger of life-threatening storm surge inundation 
over portions of eastern North Carolina and southeastern Virginia, 
including the Pamlico and Albemarle Sounds, and the lower 
Chesapeake Bay, where Storm Surge Warnings are in place.  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  21/2100Z 29.2N  75.9W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  22/0600Z 30.8N  75.8W   40 KT  45 MPH...POTENTIAL TROP CYCLONE
 24H  22/1800Z 32.6N  76.0W   45 KT  50 MPH...POTENTIAL TROP CYCLONE
 36H  23/0600Z 33.8N  76.5W   50 KT  60 MPH
 48H  23/1800Z 35.6N  77.0W   50 KT  60 MPH
 60H  24/0600Z 37.3N  76.9W   35 KT  40 MPH
 72H  24/1800Z 38.7N  76.1W   30 KT  35 MPH...POST-TROPICAL
 96H  25/1800Z 40.0N  74.0W   25 KT  30 MPH...POST-TROPICAL
120H  26/1800Z...DISSIPATED

$$
Forecaster Pasch

[yoda]

TSWs extended northward into LWX territory 

BULLETIN
Potential Tropical Cyclone Sixteen Advisory Number   2
NWS National Hurricane Center Miami FL       AL162023
500 PM EDT Thu Sep 21 2023

...LOW EXPECTED TO STRENGTHEN OFF THE SOUTHEAST U.S. COAST AND BRING 
TROPICAL STORM CONDITIONS AND THE POTENTIAL FOR LIFE-THREATENING 
STORM SURGE BEGINNING ON FRIDAY...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.2N 75.9W
ABOUT 345 MI...550 KM SE OF CHARLESTON SOUTH CAROLINA
ABOUT 415 MI...670 KM S OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


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

A Storm Surge Warning is in effect from Duck, North Carolina, 
to Chincoteague Virginia, including Chesapeake Bay south of 
Windmill Point, and for the Neuse River, the Pamlico River, and 
portions of Pamlico Sound.

The Tropical Storm Warning has been extended northward in
Chesapeake Bay to North Beach, and into the Tidal Potomac to Cobb
Island.

A Storm Surge Watch has been issued for the Tidal Potomac south of 
Colonial Beach.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Duck, North Carolina to Chincoteague Virginia
* Chesapeake Bay south of Windmill Point
* Neuse River, Pamlico River, and portions of Pamlico Sound

A Tropical Storm Warning is in effect for...
* Cape Fear NC to Fenwick Island DE
* Albemarle and Pamlico Sounds
* Tidal Potomac south of Cobb Island
* Chesapeake Bay south of North Beach

A Storm Surge Watch is in effect for...
* Surf City NC to Duck NC
* Chesapeake Bay north of Windmill Point to Smith Point
* Tidal Potomac south of Colonial Beach
* Albemarle and the remainder of Pamlico Sound

[yoda]

So looks like S MD will be put into TSWs

ETA - Calvert and St. Mary's under Tropical Storm Warning 

[Eskimo Joe]

19 minutes ago, yoda said:

So looks like S MD will be put into TSWs

ETA - Calvert and St. Mary's under Tropical Storm Warning 

Makes sense given the fetch.

[Eskimo Joe]

Looks like all Lower Eastern Shore counties have a Tropical Storm Warning.