GaWx

SSTs near the LLC are ~81-82F but rise to ~84 in the Gulf Stream, which is centered near 80W where this is headed.

Light W winds found by recon and newest convection appears to be just N of the LLC of Invest 92L.

Recon is on the way

Now up to 40% as of 8AM

June landfalls NE MX N of 20N/ENSO/E US winter 2024: Alberto TS + possible 2nd/likely Nina/TBD 2016: Danielle TS/mod Niña/mild 2011: Arlene TS/mod Niña/mild 2010: Alex H/strong Niña/cold 2005: Bret TS/weak Niña/normal 1959: Beulah TD/neutral/mild 1958: Alma TS/weak Nino/cool to cold 1954: Alice H/weak Niña/normal 1936: #2 TS/neutral/mild 1924: #1 TS/mod Niña/normal to mild 1922: #1 TS/cold neutral/cool to mild 1865: #2 TS/weak Nino/no data The # of CONUS hurricane landfalls for those seasons averaged near normal (2.2) but were all over the map (0 to 6). Year: CONUS H landfalls 2024: TBD 2016: 2 2011: 1 2010: 0 2005: 6 1959: 3 1958: 1 1954: 3 1936: 3 1924: 3 1922: 0 1865: 2

I just happened to check last night to see how rare this has been. There have been only 12 years since 1851 with a TS+ hitting NE MX in June. But 5 have been just since 2005! Keep in mind there’s a chance there will end up being not just one but two (first time on record). Here’s the data along with fall/winter ENSO (using RONI for 1950+ and Webb ONI pre 1950) and E US winter temperatures: June landfalls NE MX N of 20N/ENSO/E US winter 2024: Alberto TS + possible 2nd/likely Nina/?? 2016: Danielle TS/mod Niña/mild 2011: Arlene TS/mod Niña/mild 2010: Alex H/strong Niña/cold 2005: Bret TS/weak Niña/normal 1959: Beulah TD/neutral/mild 1958: Alma TS/weak Nino/cool to cold 1954: Alice H/weak Niña/normal 1936: #2 TS/neutral/mild 1924: #1 TS/mod Niña/normal to mild 1922: #1 TS/cold neutral/cool to mild 1865: #2 TS/weak Nino/no data The # of CONUS hurricane landfalls for those seasons averaged near normal (2.2) but were all over the map (0 to 6). Year: CONUS H landfalls 2016: 2 2011: 1 2010: 0 2005: 6 1959: 3 1958: 1 1954: 3 1936: 3 1924: 3 1922: 0 1865: 2

Invest 92L was designated earlier this evening and is headed WNW/NW toward the SE coast early Fri. I’m extra interested in following this despite pretty low odds of it becoming a TD because it is headed toward (near) my area and may bring some rain late week, regardless. It would be nice if it could bring decent rains to the very dry areas but that’s not looking likely as of now. Here’s the thread for anyone interested:

I started an Invest 92L thread: @WxWatcher007@ed2kayak

The area in the SW Atlantic being watched since the weekend was designated Invest 92L earlier this evening. This evening’s TWO also raised odds of TCG back up from 20% to the Saturday max of 30%. Although several models had this as either a TD or TS landfalling in the SE US Thu/Fri on at least one run on Saturday (GFS/Euro/UKMET/ICON) and the GFS continued that into Sunday, no model has shown a TC for the last couple of days. Instead they all have been showing either a very weak LLC or just a trough. Since this is likely headed toward (fairly close to) my general area and will probably give me at least a little rain late week, I’m following this pretty closely despite odds still being pretty low for TCG. Even if it there’s no TCG, it will still be interesting to track. Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 PM EDT Wed Jun 19 2024 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: Active Systems: The National Hurricane Center is issuing advisories on Tropical Storm Alberto, located over the southwestern Gulf of Mexico. 1. Southwestern Atlantic Ocean (AL92): A small area of low pressure has formed about 300 miles east of the northwestern Bahamas this evening with disorganized shower and thunderstorm activity. While environmental conditions are only marginally conducive due to nearby dry air, further development of this system is possible while the low moves west-northwestward and approaches the northeastern coast of Florida or Georgia early on Friday. * Formation chance through 48 hours...low...30 percent. * Formation chance through 7 days...low...30 percent.

Based on the TWO image, it appears that the NHC is raising the chance from 20% to 30%. I didn’t expect that. I don’t see the text yet. Here it is: Southwestern Atlantic Ocean (AL92): A small area of low pressure has formed about 300 miles east of the northwestern Bahamas this evening with disorganized shower and thunderstorm activity. While environmental conditions are only marginally conducive due to nearby dry air, further development of this system is possible while the low moves west-northwestward and approaches the northeastern coast of Florida or Georgia early on Friday. * Formation chance through 48 hours...low...30 percent. * Formation chance through 7 days...low...30 percent.

Regarding the SW Atlantic system, they just designated this as Invest 92L though the TWO chances remain low: Southwestern Atlantic Ocean: An area of showers and thunderstorms located a few hundred miles east of the Bahamas is associated with a surface trough of low pressure. Environmental conditions are marginally conducive for some gradual development of this system during the next few days while it moves westward or west-northwestward. The system is forecast to approach the coast of the southeastern United States by Friday. * Formation chance through 48 hours...low...20 percent. * Formation chance through 7 days...low...20 percent. Currently, no model has a TC from this. At most the models have a very weak low and more like a trough. But you never know for sure.

Alberto to be named as of 11AM advisory per bottom of this: https://www.ssd.noaa.gov/PS/TROP/DATA/ATCF/NHC/bal012024.dat

Quite breezy conditions off the ocean making it tolerable the last couple of days. This was helped today by highs staying in the 80s throughout the area along with mid 60s dews. Going to get a good walk in shortly in the breeziness.

Interestingly fwiw, the new UKMET (12Z) has no TC from this per their textual output for the first time in at least 5 runs. Not saying it will necessarily be right though. I suspect it’s going to be a borderline call either way.

Thanks for analyzing it this way. Good stuff! Note that: 1) Most (4 of 6) of the "in range" were for El Nino. The Euro clearly has performed best during El Nino with an avg miss of only +0.2. But during others it missed on avg by +0.7 and was too warm all 11 times even though twice it was only off by ~+0.2. So, with El Nino being done, the reasonable best case for this year imo is a miss of only +0.2 meaning ONI low point of -0.5. 2) Note that even for 5 of the 6 "in range", it missed slightly too warm rather than slightly too cool. Of all 17 years, only 2015 verified too cool!

And recent BoM runs have been even warmer than the Euro’s cold neutral with slightly warm neutral for autumn ONI’s low point! But last year it had the strongest warm bias.

Actually with regard to CONUS H landfall risks (especially NE GOM, FL and the rest of the E coast), I’ve found maximum risks ON AVG when ASO averaged La Niña is weak rather than stronger. That doesn’t mean there haven’t been bad years when ASO La Niña was on the stronger side, of course, as I’m talking average. And to reiterate, the June Euro runs have averaged a whopping 0.7C too warm for ONI progs in OND when there was no El Niño based on the avg since 2007:

0Z UKMET: a little further S/still TS NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 36 HOURS FORECAST POSITION AT T+ 36 : 22.5N 94.0W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 19.06.2024 36 22.5N 94.0W 999 31 0000UTC 20.06.2024 48 22.1N 95.5W 998 35 1200UTC 20.06.2024 60 23.0N 98.4W 1000 38 0000UTC 21.06.2024 72 CEASED TRACKING

1. Maybe wx recon something? Just guessing 2. The 18Z GFS is the weakest for the SW Atlantic since way back to the 6Z June 15th run as it has virtually no closed LLC.

BULLETIN Potential Tropical Cyclone One Advisory Number 1...Corrected NWS National Hurricane Center Miami FL AL012024 400 PM CDT Mon Jun 17 2024 ...LOW PRESSURE AREA OVER THE BAY OF CAMPECHE EXPECTED TO BRING HEAVY RAINFALL THREAT TO PARTS OF THE WESTERN GULF COAST... ...TROPICAL STORM WATCH ISSUED FOR PARTS OF THE COAST OF TEXAS AND NORTHEASTERN MEXICO... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...20.3N 93.2W ABOUT 380 MI...615 KM SE OF LA PESCA MEXICO ABOUT 470 MI...755 KM SE OF BROWNSVILLE TEXAS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...NNW OR 345 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Tropical Storm Watch has been issued for the Texas coast from Port O'Connor southward to the mouth of the Rio Grande. The government of Mexico has issued a Tropical Storm Watch for the northeastern coast of Mexico south of the mouth of the Rio Grande to Boca de Catan. —————- Potential Tropical Cyclone One Discussion Number 1 NWS National Hurricane Center Miami FL AL012024 400 PM CDT Mon Jun 17 2024 Satellite, surface, and aircraft data show that the center of the large low pressure area is over the Bay of Campeche with a central pressure near 1001 mb. The system currently does not have the structure of a tropical cyclone, as the associated convection is poorly organized and the maximum winds are located about 200-250 n mi northeast of the center. The various global models forecast this band of stronger winds to start moving onto the western Gulf coast on Wednesday, and a Tropical Storm Watch is required at this time. Thus, advisories are being initiated on Potential Tropical Cyclone One. The initial motion is 345/6. This general motion should continue for the next 24 h or so, although there could be some erratic motion due to center reformation. After that, the cyclone is expected to turn west-northwestward and westward on the south side of a mid- to upper-level ridge over the northern Gulf coast. This should steer the system into northeastern Mexico between 48-72 h. While there are differences in details due to the disorganized nature of the system, the track guidance is in good agreement on this general scenario. The global models suggest that some deepening of the central pressure could occur, although none of them currently forecast the system to tighten up into a classic tropical cyclone. Based on that, the intensity forecast calls for only modest strengthening. There is a chance than a small-scale vorticity center inside the large cyclonic envelope may develop enough convection to form a tighter wind core as suggested by the GFS, and based on this possibility the forecast has the system becoming a tropical storm in about 36 h. However, there is a chance the system will never become a tropical cyclone. issued. FORECAST POSITIONS AND MAX WINDS INIT 17/2100Z 20.3N 93.2W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 18/0600Z 21.1N 93.4W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 24H 18/1800Z 22.2N 93.8W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 36H 19/0600Z 22.9N 95.0W 35 KT 40 MPH...TROPICAL CYCLONE 48H 19/1800Z 23.4N 96.4W 40 KT 45 MPH...TROPICAL CYCLONE 60H 20/0600Z 23.8N 97.7W 40 KT 45 MPH...TROPICAL CYCLONE 72H 20/1800Z 24.0N 98.9W 30 KT 35 MPH...INLAND 96H 21/1800Z 24.0N 101.4W 20 KT 25 MPH...INLAND 120H 22/1800Z...DISSIPATED $$ Forecaster Beven

Outside of the GFS/GEFS, which to me don’t look impressive, the 12Z model consensus has only an open wave. I continue to predict this won’t become a TD with 90% confidence. But I’ll still keep watching the models and satellite images as in my mind it’s ~10% rather than 0% as I haven’t totally written it off just yet.

12Z UKMET: still has a TS NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 30 HOURS FORECAST POSITION AT T+ 30 : 22.8N 91.4W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 19.06.2024 36 23.6N 92.6W 997 36 1200UTC 19.06.2024 48 23.6N 95.0W 997 36 0000UTC 20.06.2024 60 23.3N 95.2W 995 40 1200UTC 20.06.2024 72 25.1N 98.9W 998 39 0000UTC 21.06.2024 84 CEASED TRACKING

Looks broad on models but chances still increasing for a TC: Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 AM EDT Mon Jun 17 2024 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: Southwestern Gulf of Mexico: Satellite imagery and surface observations indicate that a broad area of low pressure is forming over the Bay of Campeche. Environmental conditions appear conducive for additional gradual development, and a tropical depression or tropical storm is likely to form by midweek while it moves slowly westward or west-northwestward toward the western Gulf coast. Regardless of development, several days of heavy rainfall are expected across portions of southern Mexico and Central America, and these rains are likely to cause life-threatening flooding and flash flooding. Locally heavy rainfall is also expected to spread over portions of the northwestern coast of the Gulf of Mexico by the middle of the week. In addition, gale warnings have been issued for portions of the Gulf of Mexico, and more information on those warnings is available in High Seas Forecasts issued by the National Weather Service. Interests along the western and northwestern Gulf coasts should monitor the progress of this system. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate the system later today. * Formation chance through 48 hours...high...70 percent. * Formation chance through 7 days...high...70 percent. *This is now Invest 91L.

0Z UKMET: a little further north than the 12Z run; still has a TS NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS FORECAST POSITION AT T+ 54 : 23.6N 94.4W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 19.06.2024 60 23.5N 94.7W 998 35 0000UTC 20.06.2024 72 23.4N 95.6W 997 39 1200UTC 20.06.2024 84 24.9N 97.9W 999 38 0000UTC 21.06.2024 96 CEASED TRACKING

Based on the weaker trend today for the potential SW Atlantic low including the brand new 0Z model consensus, it wouldn’t surprise me if the NHC were to lower the 7 day 30% lemon to 20% soon. I’ve seen enough to feel confident that there won’t be a TC from this. The 0Z ICON, GFS, CMC, and UKMET have no TC from it.