HURRICANE LEE FORECAST SYNOPSIS…WATCHES LIKELY LATER TODAY OR TONIGHT FOR PORTIONS OF NEW ENGLAND AND ATLANTIC CANADA…ISSUED SEP. 13, 2023…12:00 NOON EDT

ALL forecasts herein are the result of my analysis, (to which you will see me at times, insert excerpts from various agencies due to the nature of the importance of the information) and I am solely responsible for the content.  As ALWAYS, follow the National Hurricane Center, National Weather Service, and your local Emergency Management officials for emergency decisions.  In addition, this is strictly a FORECAST OFFICE.  I CANNOT make decisions regarding travel plans, etc.  My purpose, is to provide you the information, based solely on information I analyze, and the accuracy of the information at hand of the time of analysis, so you may make informed decisions.
(T. F. “Storm” Walsh)

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I will reiterate, my forecasts are based on the available information at the time of analysis, and are only as accurate as the information analyzed and the solutions provided.  Keep in mind, if a forecast doesn’t exactly pan out, remember, the atmosphere is fluid in motion.  When models are being analyzed, that’s just one run, and I have to go with what is presented.  After that, models don’t update again for another 4 – 6 hours, so, what happens between that time is unknown, and forecast conditions can change slightly, to greatly.  This will have an effect on my actual forecast.

The following is my outlook forecast for the 2023 Atlantic Hurricane Season:
STORM W SEASONAL FORECAST
TOTAL NAMED STORMS: 14– 16
TOTAL HURRICANES :        5 – 7
MAJOR HURRICANES:        3 – 4

AVERAGE HURRICANE SEASON:
TOTAL NAMED STORMS: 14
TOTAL HURRICANES:         7
MAJOR HURRICANES:        3

SEASON TOTALS:
NAMED STORMS:          13
HURRICANES:                 5
MAJOR HURRICANES:  3

Given that the NHC has named at least 3, if not more, garbage systems, I had to increase my seasonal forecast slightly.

The following are the storm names for the 2023 hurricane season.  As each storm is named, they will be colored in red in order to keep track of the used names in the list:

Arlene Bret Cindy Don Emily Franklin Gert Harold Idalia Jose Katia
Lee Margot Nigel Ophelia Philippe Rina Sean Tammy Vince Whitney

Greetings everyone! 
As a reminder, when forecasting tropical systems, if there are numerous systems to deal with, I always update on the systems that may present an impact or threat to either the U. S. or the Caribbean islands.  Anything far out in the Atlantic or something that may re-curve, take a lower priority as there is more time to deal with them.

Hurricane LEE  a remains a Category 3 hurricane.  As of the 11:00 a.m. EDT advisory from the NHC, the following was available on LEE:
11:00 AM AST Wed Sep 13
Location: 26.4°N 67.2°W
Moving: NNW at 9 mph
Min pressure: 948 mb / 27.99 in
Max sustained: 115 mph
WEATHERNERDS GOES 16 HURRICANE LEE LOOP IMAGERY


LEE is now moving toward the NNW.  Based on my analysis of the current and forecast steering pattern, LEE should continue this motion through today, and should begin the north motion sometime later tomorrow, feeling the influence of the current trof in place.  Analysis this morning of the global models, and new addition Spire weather model 500 mb anomalies forecast, I have not changed my position on the model guidance having a good probability of shifting further left.  ALL of the models indicate as LEE moves north, the current trof will be responsible for the northward motion, but does not carry LEE out.  It is noted as the approaching trof moves eastward, ridging is now forecast to build north of LEE which is the red and orange in the maps, allowing him to move more toward the approaching trof, and is reflected as of the last run of the ECMWF EPS:



12Z TRACK MODEL GUIDANCE

Given that modeling is spread, and the ECMWF and the ensemble had shifted left on the 00Z run, I agree pretty much with the NHC forecast track, however based on my analysis, I do believe guidance may shift left a little more on the next run.
NHC FORECAST TRACK

Based on this, residents of the New England/NE portion of the U. S. may feel more of an effect from LEE than previously thought, and should monitor the progress of this storm.  Residents should be aware that a Tropical Storm Warning and Hurricane Watch could be issued by tonight or tomorrow morning, and should review their preparedness plans now!

Analysis of the satellite of the satellite loop imagery did indicate concentric eyewalls and some erosion of the western eyewall.  Analysis of water vapor imagery indicated this was due to some slight ingestion of dry air.  Not much has changed as far as wind shear and the upper level outflow pattern.  Recent info from CIMSS still indicates moderate shear of about 15 – 20 knots over LEE, however the robust upper level outflow pattern is holding an effect of this shear in check:
CIMSS WIND SHEAR AND UPPER LEVEL WINDS


Based on the OHC map from CIMSS, LEE will be leaving the higher OHC in about 24 -30 hours, and will incur upwelling form previous storms.  Wind shear is forecast to increase around the same time frame, along with increasing drier air.  Given this, LEE should begin gradual weakening as reflected in the NHC intensity forecast:
INIT 13/1500Z 26.4N 67.2W 100 KT 115 MPH
12H 14/0000Z 27.6N 67.7W 95 KT 110 MPH
24H 14/1200Z 29.6N 68.2W 90 KT 105 MPH
36H 15/0000Z 31.8N 68.2W 85 KT 100 MPH
48H 15/1200Z 34.6N 67.6W 80 KT 90 MPH
60H 16/0000Z 37.9N 67.1W 75 KT 85 MPH
72H 16/1200Z 41.1N 67.2W 70 KT 80 MPH
96H 17/1200Z 46.1N 66.6W 50 KT 60 MPH…POST-TROP/INLAND
120H 18/1200Z 52.1N 56.4W 35 KT 40 MPH…POST-TROP/INLAND

Important information from the NHC discussion:
Lee is expected to gradually weaken as it moves into an environment of increasing vertical wind shear, slightly drier air, and over progressively cooler waters during the next few days. However, the large size of the system suggests that the weakening process should be slow. In addition, Lee is expected to grow in size as it gains latitude during the next few days. The NHC intensity forecast is largely the same as the previous one and fairly close to the HCCA and IVCN models. Regardless of the details, there is high confidence that Lee will be a large hurricane near the coast of New England Friday night and Saturday.

The following graphic is the latest display of the wind field for LEE based on the ADT

NHC GRAPHICS PAGE
https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/203849.shtml?3-daynl
ECMWF AND WAVEWATCH 3 WAVE HEIGHTS AND DIRECTION FORECAST

SURFACE WINDS FORECAST


I will continue to monitor the progress of LEE for any significant changes that may occur to the forecast conditions, and will issued local products if and when they are issued by the NHC.