HURRICANE LEE RE-INTENSIFYING FORECAST SYNOPSIS…ISSUED SEP. 10, 2023…7:15 P.M. 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:                 4
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!  Today is the climatological peak of the Atlantic Hurricane Season.
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 has begun to re-intensify from this morning.  At 11:00 a.m., maximum sustained winds were 110 mph, making him a Category 2 hurricane on the Saffir-Simspon scale.  As of the 5:00 p.m. advisory from the NHC, the following information was available on Hurricane LEE:
5:00 PM AST Sun Sep 10
Location: 22.1°N 61.7°W
Moving: WNW at 8 mph
Min pressure: 954 mb/28.17 in
Max sustained:120 mph
WEATHERNERDS GOES 16 LEE SATELLITE LOOP IMAGERY


Maximum sustained winds have increased to 120 mph, now making LEE a Category 3 hurricane.  The most recent wind shear analysis from CIMSS still indicates the presence of SWLY shear over the hurricane, and I am having a little trouble understanding this, as to whether or not the global models are incorrect in their forecast of wind shear.  Current strengthening is based on the premise that even though moderate SWLY shear is present, the current outflow pattern has become much stronger and better established, with a large radial pattern, anticyclonic pattern.  This has in effect, reduced the shear, or effect of the shear.
CIMSS RECENT WIND SHEAR AND UPPER LEVEL OUTFLOW


I have been curious as to how this works, and was fortunate enough to find an article on it from an article in the AMS journals monthly weather review.  Here is an abstract from the article, followed by the link:
The implication of outflow structure for tropical cyclone (TC) rapid intensification (RI) is investigated via a climatological study using the best track, reanalysis, and infrared brightness temperature data during 1980–2019. Composite analyses are performed in a shear-relative framework for the RI events under different strengths of environmental shear. Results show that for the RI events under moderate (4.5–11 m s⁻¹) or strong (>11 m s⁻¹) environmental shear the RI onset follows a significant increase of upper-level outflow upshear of the storm, which is intimately linked with the increasing active convection upshear. The intensified outflow blocks the upper-level environmental flow and thus decreases the local shear, building an environment favorable for RI.
https://journals.ametsoc.org/view/journals/mwre/149/12/MWR-D-21-0141.1.xml

While the premise is that wind shear is forecast to increase by days 4 and 5 in the forecast period, ALL three global models, ECMWF, GFS and CMC indicate for the radial shear pattern to remain directly over the hurricane out to day 5 (120 hours) in the forecast period.  BOTH hurricane models HAFS-A and HAFS-B indicate the same thing.  I am going to use just the ECMWF as to avoid too numerous graphics.
ECMWF MSLP ANOMALY AND SHEAR FORECAST 120 HOURS


It is noted though, that some model information from the CIRA page does indicate an increase in shear in approximately 5 days.

I’ll be revisiting this just to see what is actually occurring, as it appears to me the global models have had difficulty in the shear forecast with LEE.
The 200 mb outflow pattern is forecast to remain very favorable during this time period as well.
All other factors such as PWAT, mid level humidity, and high OHC are forecast to be favorable during the next 96 hours.  Thereafter, it appears drier air will begin to affect LEE, as well as LEE moving over very low OHC.  Depending on actual forward speed (if too slow), upwelling could also affect the hurricane.  Putting everything together from my analysis, I believe LEE will continue to intensify during the next 48 hours.  Given the uncertainties of what I have explained, I have to agree at the moment with the NHC intensity forecast:
INIT 10/2100Z 22.1N 61.7W 105 KT 120 MPH
12H 11/0600Z 22.7N 62.7W 115 KT 130 MPH
24H 11/1800Z 23.3N 63.9W 120 KT 140 MPH
36H 12/0600Z 23.8N 65.1W 120 KT 140 MPH
48H 12/1800Z 24.2N 66.2W 115 KT 130 MPH
60H 13/0600Z 24.7N 67.0W 105 KT 120 MPH
72H 13/1800Z 25.6N 67.6W 100 KT 115 MPH
96H 14/1800Z 28.9N 68.0W 90 KT 105 MPH
120H 15/1800Z 33.6N 67.4W 80 KT 90 MPH
LEE was moving toward the WNW.  Based on current steering, I believe LEE may still move just a little further left, prior to the turn, but should continue on the same general WNW track for the next 2 days.  Based on forecast steering and analysis of 500 mb geopotential height forecast maps, the trough currently over the SEUS is forecast to cause a weakness in the ridge, and LEE should begin to slow further, and begin the turn to the north.  As stated, with the orientation of the current steering pattern, and the forecast for LEE to attain 140 mph, he COULD reinforce the southern portion of the ridge, and he could nudge a little further left.  Based on this, I agree with the NHC forecast track at the moment, which is inline with the 18Z guidance which is very tightly clustered.
NHC FORECAST TRACK MAP

18Z TRACK GUIDANCE

CURRENT LAYER MEAN STEERING



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


I will continue to monitor the progress of LEE for any significant changes that may occur to the forecast conditions.

The following map will allow to get information from your NWS office.
NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

NWS DOPPLER RADAR LOOP (LINKED, CLICK RADAR MAP)

RAP RADAR (CLICK IMAGE THEN RADAR SITE…ONCE YOU CLICK THE SITE, GO TO LOOP DURATION TO CREATE A LOOP)
You may direct any questions by contacting me personally, ANYTIME, at: twalsh22000@yahoo.com

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS