Sunday, September 10, 2023

Lee Regains Major Hurricane Status (Category 3), Is Increasingly Likely To Impact Our Region















































000
WTNT33 KNHC 110247
TCPAT3

BULLETIN
Hurricane Lee Advisory Number  23
NWS National Hurricane Center Miami FL       AL132023
1100 PM AST Sun Sep 10 2023

...LEE GROWING LARGER BUT MAXIMUM SUSTAINED WINDS HAVE NOT YET
INCREASED...
...HAZARDOUS BEACH CONDITIONS EXPECTED TO SPREAD THROUGH THE WESTERN
ATLANTIC DURING THE WEEK...

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.6N 62.2W
ABOUT 310 MI...500 KM N OF THE NORTHERN LEEWARD ISLANDS
ABOUT 690 MI...1110 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.06 INCHES

WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Hurricane Lee was located 
near latitude 22.6 North, longitude 62.2 West. Lee is moving toward 
the northwest near 8 mph (13 km/h). A slower west-northwestward 
motion is expected during the next few days. On the forecast track, 
Lee is expected to pass well north of the northern Leeward Islands, 
the Virgin Islands, and Puerto Rico during the next day or two.

NOAA aircraft data indicate that maximum sustained winds remain 
near 120 mph (195 km/h) with higher gusts. Lee is a category 3 
hurricane on the Saffir-Simpson Hurricane Wind Scale. Additional 
strengthening is forecast over the next day or so, followed by 
gradual weakening.

Lee has been growing in size, with hurricane-force winds now 
extending outward up to 75 miles (120 km) from the center and 
tropical-storm-force winds extending outward up to 175 miles (280 
km).

The minimum central pressure measured by NOAA reconnaissance
aircraft is 950 mb (28.06 inches).

HAZARDS AFFECTING LAND
----------------------
Key messages for Lee can be found in the Tropical Cyclone Discussion
under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC and on the
web at hurricanes.gov/text/MIATCDAT3.shtml

SURF:  Swells generated by Lee are affecting portions of the Lesser 
Antilles, the British and U.S. Virgin Islands, Puerto Rico, 
Hispaniola, the Turks and Caicos Islands, the Bahamas, and Bermuda. 
These swells are likely to cause life-threatening surf and rip 
current conditions. Dangerous surf and rip currents have begun to 
reach portions of the southeast U.S. coast and are forecast to 
worsen and spread northward along much of the U.S. East Coast during 
the next couple of days. Please consult products from your local 
weather office.

NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Papin


311 
WTNT43 KNHC 110252
TCDAT3

Hurricane Lee Discussion Number  23
NWS National Hurricane Center Miami FL       AL132023
1100 PM AST Sun Sep 10 2023

There has been a wealth of data to dig though this evening for 
Hurricane Lee. Observations from both satellite imagery and this 
evening's NOAA-P3 mission indicate the hurricane has become more 
symmetric in both its convective pattern and wind field. On 
satellite, Lee has once again become more impressive with a warming 
eye surrounded by cold -65 to -75C eyewall cloud tops. In response, 
the subjective Dvorak estimates have been increasing, both T6.0/115 
kt from TAFB and SAB. In addition, a single closed eyewall of 25 n 
mi in diameter was reported by the NOAA aircraft, which has also 
been observed by the TDR data and an earlier 2151 UTC SSMIS 
microwave pass. The surface pressure has also been dropping, with 
the most recent dropsonde in the eye reporting 950 mb. However, the 
winds have yet to respond to the decreasing pressure, with peak 
flight-level winds of 108 kt, SFMR at 103 kt, and surface reduced 
TDR data also in the 100-105 kt range. All of the in-situ aircraft 
data supports maintaining an initial intensity of 105 kt this 
advisory. A Synthetic Aperture Radar (SAR) pass valid at 2213 UTC 
also showed a 105-kt peak wind, but with expanding 64-kt wind radii, 
which might explain why the winds have yet to respond to the 
pressure drop.

Track-wise, Lee continues to move west-northwestward, at 305/6 kt.
This motion is expected to generally continue with a further
slowdown in the forward motion now that the mid-level ridging
influencing the storms steering has shifted more northwest in front
of the hurricane. However, this ridge is expected to then become
eroded by an approaching deep-layer trough, allowing Lee to turn
northward into the weakness produced by the trough. The track
guidance this cycle is in fairly good agreement over the next 5
days, with the largest details still related to the forward motion
of Lee after it turns northward. The NHC track forecast is pretty
much on top of the prior one, continuing to favor the consensus
aids, and is roughly in between the leftward GFS and rightward
ECMWF model solutions. Users should be reminded to not focus on the
exact forecast track, especially given Lee's forecast size at the
longer range, and the average day 4 and 5 track errors are about
145 and 200 miles, respectively.

Data from an earlier NOAA G-IV mission sampling the environment 
around Lee indicated that the vertical wind shear that had been 
affecting the hurricane has mostly subsided, with the dropsonde data 
showing well-established outflow to the north, and a deep-layer of 
cyclonic flow to the south associated with Lee's broad and deep 
circulation. While it is difficult to predict the inner-core changes 
associated with the cyclone, most of the intensity guidance still 
suggests Lee will intensify further over the next day or so, with a 
120-kt peak predicted in 24 hours. Afterwards, as Lee continues to 
slow down, it may then begin to encounter its own cold wake due to 
its expanding wind field, and the hurricane is expected to begin 
gradually weakening. This weakening should be hastened by increasing 
southwesterly vertical wind shear after 72 h as the storm also 
traverses already cooled sea-surface temperatures by Franklin and 
Idalia last week. However, the model guidance also shows Lee's 34-kt 
and 50-kt wind field continuing to expand through the forecast 
period even as the hurricane gradually weakens.

KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, and
Bermuda through much of this week.

2. Lee could bring wind, rainfall, and high surf impacts to
Bermuda later this week.  Although it is too soon to determine the
specific timing and level of those impacts, interests on Bermuda
should monitor the latest forecasts for Lee.

3. It remains too soon to know what level of impacts, if any,
Lee might have along the U.S. East Coast and Atlantic Canada late
this week, especially since the hurricane is expected to slow
down considerably over the southwestern Atlantic.  Regardless,
dangerous surf and rip currents are expected along most of the U.S.
East Coast this week as Lee grows in size. Users should continue to
monitor updates to the forecast of Lee during the next several days.

FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 22.6N  62.2W  105 KT 120 MPH
 12H  11/1200Z 23.1N  63.1W  115 KT 130 MPH
 24H  12/0000Z 23.6N  64.4W  120 KT 140 MPH
 36H  12/1200Z 24.1N  65.5W  115 KT 130 MPH
 48H  13/0000Z 24.6N  66.4W  110 KT 125 MPH
 60H  13/1200Z 25.3N  67.2W  100 KT 115 MPH
 72H  14/0000Z 26.5N  67.7W   95 KT 110 MPH
 96H  15/0000Z 30.2N  67.9W   85 KT 100 MPH
120H  16/0000Z 35.5N  67.0W   70 KT  80 MPH

$$
Forecaster Papin


000
FXUS61 KCAR 110158
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
958 PM EDT Sun Sep 10 2023

.SYNOPSIS...
A frontal boundary will remain nearly stationary along the
Downeast coast through Monday, then move south across the Gulf
of Maine Monday night. An occluded front will approach late
Tuesday through Tuesday night, then cross the region Wednesday
through early Thursday......

......LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The cold/occluded front will cross the region Wednesday night,
while low pressure moves north along the front. Rain, possibly
heavy at times, will persist in advance of the front then begin
to diminish in the wake of the front. The front will exit across
the Maritimes early Thursday, with an upper level low
approaching late. Could still have rain early in advance of the
front, then tapering to showers in the wake of the front. The
upper low lifts north of the region Friday, with troffing
extending south across the forecast area. Generally expect
partly cloudy skies Friday, though could also have the slight
chance of a shower across mostly northern areas. Uncertainty
still exists regarding the track/timing of Hurricane Lee
Saturday into Sunday. Continue to monitor National Hurricane
Center products for the latest information on the
strength/track/timing of Lee. Regardless of the eventual
track/timing, long period swells will result in an increasing
risk of dangerous rip currents and high surf from mid to late
week. Near normal, to slightly below normal, level temperatures
expected Thursday through Sunday......

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