CATEGORY 4 HURRICANE LEE FORECAST SYNOPSIS…ISSUED SEP. 08, 2023…12:40 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!
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 weakened from early this morning, down from 165 mph to 155 mph, making him a top end Category 4 hurricane on the Saffir-Simspon scale.  As of the 11:00 a.m. advisory from the NHC, the following information was available on Hurricane LEE:
11:00 AM AST Fri Sep 8
Location: 18.2°N 54.5°W
Moving: WNW at 13 mph
Min pressure: 942 mb / 27.82 in
Max sustained: 155 mph

Current satellite loop imagery indicates the eye filled in a little earlier, possibly due to wind shear over the hurricane, however the eye has become a little more distinct in the last few frames:
WEATHERNERDS GOES 16 HURRICANE LEE SATELLITE LOOP IMAGERY


The shear over LEE at the moment is due to a shift in the center of the radial shear pattern shifting south of the hurricane bringing a SW flow over the storm.  The western side of the storm seems eroded, which may be due to some slight impingement of dry air as may be evidenced by the recent TPW loop:
CIMSS WIND SHEAR


I believe these 2 factors are what have caused LEE to weaken.

LEE is still moving to the WNW and is being steered by a mid level ridge, with a weakness noted NW of the storm in the current steering layer.  The average of this is creating the current WNW motion.  Based on analysis of forecast steering, animated MSLP maps, and 500 mb geopotential height maps, in a few days, the ridge is forecast to develop a weakness on its western periphery, with a secondary trough coming in, and the forward speed of LEE should begin to slow.  This should allow for LEE to begin heading on a more northerly component, and LEE should eventually re-curve.  Based on this, I agree with the current track guidance as it is very well clustered, and also the current NHC forecast track.  It is noted that the NHC track is just south of the consensus models.  This forecast SHOULD pan out. However, it is wise to keep a close eye on future guidance.  With a system as strong as forecast, two things can occur.  One is, the storm can “pump the ridge”, meaning a strong category 4 or category 5 hurricane can reinforce the SW portion of the ridge, thereby allowing the storm to maintain a more westerly component.  When I mention this, I do not mean a due west track.  For example, if a storm is, or is forecast to travel NW, pumping the ridge would allow for a more WNW motion, briefly.  Meteorologist Joe Bastardi from Weatherbell, who I have learned a tremendous amount from on forecasting hurricanes, explains the process:

The other headache is the hurricane will be adding heat to the ridge to its right. This is a model problem as they usually do not handle this, The hurricane literally starts changing the steering as the heat pumps the ridge, and tightens the jet with the trough to the northwest, and forces it to lift out. That is a potentially big worry here. Modelling usually is too far east several days away.

The other is, the storm can become stronger than the effect of the approaching trough, and move through it, vice being repelled.  I do believe however, we will see the first option occur.  Based on analysis of current track guidance, MSLP animations and 500 mb geopotential heights forecasts, LEE should move north of the Leeward islands and the Greater Antilles. 
NHC FORECAST TRACK MAP

Based on current track guidance, a slight bend left in track is noted, but has corrected from 06Z this morning, when LEE was stronger.  This bend is most likely due to what I have posted on “pumping the ridge”
06Z ATCF GUIDANCE

12Z GUIDANCE

CURRENT STEERING LAYER MEAN

ECMWF AND GFS 500 MB GEOPOTENTIAL HEIGHT FORECAST FROM 90 – 168 HOURS


ECMWF ENSEMBLE FORECAST

Maximum sustained winds of Hurricane LEE have decreased to 155 mph.  Based on my analysis, moderate SWLY shear is over LEE, which was mentioned earlier in this forecast.   The shear pattern is forecast to become slowly more improved during the storms trek north of the islands, along with the improvement of the 200 mb pattern, mid level RH, and precipitable water.   Although there is upper level outflow established, which has improved over the past couple of hours, the forecast still calls for the pattern to continue improving during the next few days and become textbook, directly over the storm, as well as LEE passing over some high OHC.  Based on my analysis, I believe LEE should maintain current intensity today.  However, with the improving eye structure noted in satellite imagery, and forecast of slow improvement to the shear pattern, LEE COULD re-intensify for a brief period, although the current intensity guidance continues to show slow weakening throughout the period.  ANY increase in intensity would have the chance for the track once again to continue slightly left of the forecast track.  Based on the forecast  favorable conditions, I agree with the NHC intensity forecast for the most part, however due believe short term intensification may occur.
INIT 08/1500Z 18.2N 54.5W 135 KT 155 MPH
12H 09/0000Z 19.0N 56.1W 135 KT 155 MPH
24H 09/1200Z 20.0N 57.9W 130 KT 150 MPH
36H 10/0000Z 20.8N 59.4W 125 KT 145 MPH
48H 10/1200Z 21.5N 60.8W 125 KT 145 MPH
60H 11/0000Z 22.1N 62.0W 125 KT 145 MPH
72H 11/1200Z 22.7N 63.1W 125 KT 145 MPH
96H 12/1200Z 23.5N 65.5W 120 KT 140 MPH
120H 13/1200Z 24.8N 67.5W 115 KT 130 MPH

ECMWF MSLP ANOMALY, SHEAR, PWAT, MID LEVEL RH, AND 200 MB STREAMLINE FORECAST 90 HOURS

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 day!

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