TROPICAL STORM LEE APPROACHING HURRICANE STATUS…FORECAST TO BECOME A STRONG CATEGORY 4 HURRICANE…FORECAST SYNOPSIS…ISSUED SEP. 06, 2023…12:10 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:          12
HURRICANES:                 3
MAJOR HURRICANES:  2

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.

Tropical Storm LEE continues to become quickly better organized, and has strengthened over night, and is coming close to hurricane force.  As of the 11:00 a.m. advisory from the NHC, the following information was available on Tropical Storm LEE:
11:00 AM AST Wed Sep 6
Location: 14.1°N 45.5°W
Moving: WNW at 14 mph
Min pressure: 994 mb / 29.35 in.
Max sustained: 70 mph
WEATHERNERDS GOES 16 TROPICAL STORM LEE SATELLITE LOOP IMAGERY


LEE is currently moving to the WNW and is being steered by a mid level ridge, with a weakness noted north 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, at about days 7 – 8, the ridge is forecast to develop a weakness on its western periphery, with a trough coming in.  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.  The other is, the storm can become stronger than the effect of the approaching trough, and move through it, vice being repelled.  I recommend residents of the Lesser and Greater Antilles still keep a close eye on this storm.  From the NHC:

The track guidance continues to show that the core of Lee will pass to the north of the northern Leeward Islands, however interests in those islands should continue to monitor the latest forecasts as the typical three- and four-day NHC track errors are about 90 and 125 n mi, respectively. The NHC track forecast is again along the southern side of the guidance envelope, between the faster and farther south HFIP corrected consensus model, and the TVCA multi-model consensus aid.
NHC FORECAST TRACK MAP

12Z ATCF GUIDANCE

ECMWF AND GFS 500 MB GEOPOTENTIAL HEIGHT FORECAST FROM 120 – 240 HOURS


ECMWF ENSEMBLE FORECAST

Maximum sustained winds of Tropical Storm LEE have increased to 70 mph.  Based on my analysis of forecast conditions, there has been no change in the forecast.  The shear pattern is forecast to become more improved during the storms trek toward the islands, along with the improvement of the 200 mb pattern, mid level RH, and precipitable water.  As of current, LEE has favorable conditions for further intensification, with along with high precipitable water, and a now established 200 mb outflow pattern.  The current shear pattern shows the center of the radial pattern is displaced north of the center of LEE, which is inducing some slight ENE shear over the storm, of about 10 – 15 knots.  However the forecast still calls for the pattern to continue improving during the next 96 hours with shear relaxing, and at 120 hours calls for these conditions to become textbook, directly over the storm.  Based on my analysis, I believe LEE should attain hurricane status this afternoon or this evening.  Based on the premise of extremely favorable conditions materializing, LEE should go through a period of rapid intensification sometime within the next 48 hours.  Given all this, I am forecasting LEE to become a major hurricane, reaching category 4 status.  Right now, I agree with the NHC intensity forecast
ECMWF SHEAR, PWAT, MID LEVEL RH, AND 200 MB STREAMLINE FORECAST 120 HOURS




NHC INTENSITY FORECAST
INIT 06/1500Z 14.1N 45.5W 60 KT 70 MPH
12H 07/0000Z 14.8N 47.3W 75 KT 85 MPH
24H 07/1200Z 15.7N 49.6W 85 KT 100 MPH
36H 08/0000Z 16.6N 52.2W 95 KT 110 MPH
48H 08/1200Z 17.6N 54.7W 105 KT 120 MPH
60H 09/0000Z 18.7N 56.9W 120 KT 140 MPH
72H 09/1200Z 19.8N 59.2W 130 KT 150 MPH
96H 10/1200Z 21.5N 62.8W 130 KT 150 MPH
120H 11/1200Z 22.9N 65.7W 130 KT 150 MPH
I will continue to monitor the progress of LEE for any significant changes that may occur to the forecast conditions.

On another note, evidently the Vitart solution did not materialize where the map indicates development near the Texas coast when the MJO is in phase 4.  Analysis indicates the MJO did not make it to phase 4, and is currently in phase 3:

VITART PHASE 4 DEVELOPMENT
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