2024 Hurricane Season Discussion

[tireman4]

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Trying to narrow down the development setup next week near the Yucatan
By Matt Lanza on September 20, 2024

Headlines

We are still a few days from Caribbean development
I feel like we've been talking about this potential development in the Caribbean for days now. That's one element of hurricane season that has gotten worse in recent years: The availability and democratization of weather data has kept any and every potential disturbance in the conversation for a week or two before they even form, then for a week or two as they do their thing. In some cases, you can be talking about one system from pre-inception to finish for a month! But the availability of all this information has made our job more important to help y'all make sense of what it's saying.


The probability of Caribbean development remained at 40 percent this morning. We'll see if the afternoon update in a bit increases those odds.
Yesterday's post has aged pretty well, thankfully. Frankly, not a whole lot has changed. But I think there's a clear dichotomy taking shape now between the European modeling and the GFS modeling Yesterday, I noted how the Euro was apt to consolidate the disturbance next week near or over the Yucatan, whereas the GFS did so mostly in the Caribbean. Those models have not changed their view on this today. Trends over the last couple days have led to the European AI modeling, the AIFS to trend a little closer to the GFS solution of stronger, faster, more north and east. The ICON model is also taking that stand, so there is some slowly building support for the GFS here, I think.


The last 5 AIFS runs showing an erratic but general trend toward the more eastern outcomes for late next week.
That said, if we look at ensemble guidance, there continues to be a gigantic split among the 30 to 50 ensemble members in both the GFS and European suite. The Euro seems to be split about 80/20 favoring the western/weaker outcome, whereas the GFS is more of a 40/60 blend favoring stronger and more east/north leaning outcomes.


Latest 12z GFS Ensemble outlook shows about a 60/40 or 70/30 type split in outcomes favoring a stronger, more east and north type track over a system that stays stuck near the Yucatan.
It may have even gotten more confident in that eastward lean in today's 12z model guidance as seen above. The one big, big takeaway from both of these examples showing the AIFS and GFS Ensemble members is that there is still *very* little agreement on track, just many generalizations that can be inferred from this output.

I continue to think this sort of scenario favors either a Mexico or Yucatan impact or a Florida through New Orleans type impact on the northern Gulf Coast. I remain convinced that Texas is *not* the most likely outcome here, but I would continue advising Texans to monitor things heading into next week.

There are also gigantic timing differences here. The storms that come north and northeast tend to do so quickly, with impacts possible as early as next Thursday. So for folks in Louisiana through Florida, you would need to be ready to act as soon as Monday if this looks like a building threat. For Texas and Mexico, if the western outcome happens, this would likely remain a middling system for several days before organizing later next week and coming north next weekend. This would deliver impacts to the central Gulf Coast by next Sunday or so. That's a large spread of timing options, so folks on the Gulf Coast should be flexible with their preparedness and be ready to act early next week once things become clearer.

We will have daily posts this weekend to keep you all informed.

Elsewhere in your tropical Atlantic!
Invest 96L has developed in the open Atlantic, and between it and the remnants of Gordon, we could maybe see something try to form over the next few days. Neither system is likely to impact land.

More interestingly, we have potential for a Cabo Verde system to develop later next week. The European ensemble has been quite bullish on this. There is plentiful support for this from other modeling as well. Expect this potential to show up around midweek next week.


The Euro ensemble, as well as other models show a growing likelihood of development later next week off Africa.
Now, is this system likely to be a land threat? It's too early to say definitively, but the current thinking is that this would probably end up moving out to sea ultimately. Plenty of time to watch. No other threats are seen closer to home right now after next week's Caribbean/Gulf story.

[Pas_Bon]

With the impending landfall of a major hurricane on the Florida Gulf Coast/Big Bend area, my thoughts will be with those affected, because it could well be a very nasty storm.
That said, I'm fairy confident Hurricane Season 2024 is effectively over for the Upper TX coast. With the arrival of frontal boundaries starting to happen within 48hrs, the chances of a landfall in SETX are minimal at best.

Of course, it is still always mathematically possible, but meteorologically, I would be absolutely shocked to see anything come this way from here on out.
I don't want to jinx it, but it looks like we may have gotten through what was to be a Hellish season with relatively few direct impacts (aside from Beryl, of course).

True Fall cannot come soon enough....

[Ptarmigan]

Hurricane John made landfall on Mexico last night. It was a Category 3 hurricane. It may have been stronger. It is lingering over Mexico and dumping heavy rain.

[Ptarmigan]

With the impending landfall of a major hurricane on the Florida Gulf Coast/Big Bend area, my thoughts will be with those affected, because it could well be a very nasty storm.
That said, I'm fairy confident Hurricane Season 2024 is effectively over for the Upper TX coast. With the arrival of frontal boundaries starting to happen within 48hrs, the chances of a landfall in SETX are minimal at best.

Of course, it is still always mathematically possible, but meteorologically, I would be absolutely shocked to see anything come this way from here on out.
I don't want to jinx it, but it looks like we may have gotten through what was to be a Hellish season with relatively few direct impacts (aside from Beryl, of course).

True Fall cannot come soon enough....

Hurricanes have made landfall in October and November in the past.

[tireman4]

Western Caribbean:
An area of low pressure could form over the western Caribbean by the
middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter, while the system moves
generally northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

[tireman4]

Western Caribbean:
An area of low pressure could form over the western Caribbean Sea by
the middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter while the system moves
generally northwestward, potentially entering the Gulf of Mexico by
the end of next week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

[tireman4]

Central Tropical Atlantic (AL98):
Showers and thunderstorms associated with an area of low pressure
located midway in between the Cabo Verde Islands and the Lesser
Antilles continues to become better organized. This disturbance is
already producing gale-force winds. Environmental conditions are
conducive for further development and a tropical depression or storm
could form today while the system moves generally westward to
west-northwestward at 10 to 15 mph. The system is then forecast to
slow down and turn north-northwestward by this weekend. Additional
information on this system, including gale warnings, can be found in
High Seas Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[tireman4]

...ISAAC BECOMES A HURRICANE...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...37.0N 48.5W
ABOUT 1175 MI...1895 KM W OF THE AZORES
ABOUT 980 MI...1575 KM ENE OF BERMUDA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...E OR 90 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES

[tireman4]

We have Tropical Storm Joyce...

AL, 11, 2024092712, , BEST, 0, 178N, 424W, 35, 1006, TS, 34, NEQ, 60, 0, 0, 0, 1011, 180, 50, 45, 0, L, 0, , 0, 0, JOYCE, M, 0, , 0, 0, 0, 0, genesis-num, 026, TRANSITIONED, alB82024

BULLETIN
Tropical Storm Joyce Advisory Number 1
NWS National Hurricane Center Miami FL AL112024
1100 AM AST Fri Sep 27 2024

...TROPICAL STORM JOYCE FORMS OVER THE CENTRAL TROPICAL ATLANTIC
OCEAN...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...18.1N 42.9W
ABOUT 1325 MI...2130 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHESto al112024,

[Cpv17]

Looks like there could be another storm in the Gulf in a few days. Louisiana to FL should watch for it. Possibly Mexico, but the western to NW Gulf should be safe.

[tireman4]

Tropical Storm 11L (Joyce)


UW-CIMSS Automated Satellite-Based
Advanced Dvorak Technique (ADT)
Version 9.1

Current Intensity Analysis



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 27 SEP 2024 Time : 172020 UTC
Lat : 18:18:31 N Lon : 43:16:27 W


CI# /Pressure/ Vmax
2.7 /1003.1mb/ 39.0kt


Final T# Adj T# Raw T#
2.7 2.9 3.0

[tireman4]

000
WTNT31 KNHC 271435
TCPAT1

BULLETIN
Tropical Storm Joyce Advisory Number 1
NWS National Hurricane Center Miami FL AL112024
1100 AM AST Fri Sep 27 2024

...TROPICAL STORM JOYCE FORMS OVER THE CENTRAL TROPICAL ATLANTIC
OCEAN...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...18.1N 42.9W
ABOUT 1325 MI...2130 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Joyce was
located near latitude 18.1 North, longitude 42.9 West. Joyce is
moving toward the northwest near 13 mph (20 km/h) and this general
motion is expected to continue through Sunday with a gradually
slower forward speed. On Monday, a gradual turn to the north is
forecast.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Gradual strengthening is expected through Saturday, followed by
gradual weakening through early next week.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center.

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Bucci

[tireman4]

ZCZC MIATCPAT5 ALL
TTAA00 KNHC DDHHMM CCA

BULLETIN
Hurricane Isaac Advisory Number 7...Corrected
NWS National Hurricane Center Miami FL AL102024
1100 AM AST Fri Sep 27 2024

Correct headline

...HURRICANE ISAAC HEADING EASTWARD OVER THE NORTH CENTRAL ATLANTIC
OCEAN...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...37.4N 46.8W
ABOUT 1080 MI...1740 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...ENE OR 65 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Isaac was located
near latitude 37.4 North, longitude 46.8 West. Isaac is moving
toward the east-northeast near 18 mph (30 km/h). A gradual turn to
the east-northeast with a slight acceleration in forward speed is
expected over the few days.

Maximum sustained winds are near 75 mph (120 km/h) with higher
gusts. Additional strengthening is expected during the next day or
so followed by gradual weakening by the end of this weekend.

Hurricane-force winds extend outward up to 15 miles (30 km) from the
center and tropical-storm-force winds extend outward up to 70 miles
(110 km).

The estimated minimum central pressure is 981 mb (28.97 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Isaac and a large wind fetch from a
deep-layer trough could spread into the Azores by this weekend.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local weather
office.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Bucci

NNNN

[tireman4]

000
ABNT20 KNHC 271752
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 27 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Depression Helene, located inland over the southern Appalachians,
on Hurricane Isaac, located over the central Subtropical Atlantic
Ocean, and on recently-formed Tropical Storm Joyce, located over
the central Tropical Atlantic Ocean.

Western Caribbean:
An area of low pressure could form over the western Caribbean Sea by
the middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter while the system moves
generally northwestward, potentially entering the Gulf of Mexico by
the end of next week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

Eastern Tropical Atlantic:
An area of low pressure could form over the eastern tropical
Atlantic by the early to middle part of next week. Environmental
conditions are expected to be conducive for slow development
thereafter while the system moves generally northwestward at 10 to
15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

&&
Public Advisories on Tropical Storm Joyce are issued under WMO
header WTNT31 KNHC and under AWIPS header MIATCPAT1.
Forecast/Advisories on Tropical Storm Joyce are issued under WMO
header WTNT21 KNHC and under AWIPS header MIATCMAT1.

$$
Forecaster Bucci/Rosado

[Stratton20]

12z Euro has a weak system resulting from a TW in the caribbean that moves into the middle texas coast and slows down lol

[tireman4]

By Matt Lanza on September 27, 2024

As of 3 PM ET, there are 16 "catastrophic" Flash Flood Emergencies in effect across the Appalachians. They range from Virginia to North Carolina to Tennessee and South Carolina and Georgia. The criteria for issuing flash flood emergencies is much more stringent than that of the typical flash flood warning. There needs to be an imminent risk of severe damage and/or loss of life. At least 16 counties or communities are reconciling that at present, not to mention the ones that have already been through things today. Rain is finally, mercifully winding down. But as noted this morning, the damage has been done.


Helene's center is on the Kentucky/Tennessee border and being absorbed by an upper low in that region, leading to a widespread heavy rain event from Tennessee and Arkansas into the Ohio Valley. (College of DuPage)
The next phase for Helene will be as a localized flood producer in the Ohio Valley, but hopefully not as prolific as we've seen in Appalachia.


Another 1 to 3 inches of rain is possible from western Tennessee across the Ohio Valley to Cincinnati.
It's been tough to keep tabs on reports and damage and incidents. I think the death toll has come in around 25 so far based on various reports. Power outages sit around 4 and a half million or so at this hour. Rain totals have been enormous across Georgia, South Carolina, and North Carolina, with over 20 inches in some spots.


Preliminary estimate of rain totals across Upstate South Carolina and western North Carolina as of this morning.
Just one example of a river gauge gone crazy is in Asheville, NC for the Swannanoa River at Biltmore.


The Swannanoa River at Biltmore will crest about 6 feet or more above the previous record set in 1916. By some accounts, this may be the highest since at least the 1790s.
Forecast to exceed the flood of 1916, the gauge likely topped the presumed 26 foot level set back in spring 1791 according to Tennessee Valley Authority records. Whatever the case, this will be a devastating flooding event in Asheville and western North Carolina as a whole. According to the Georgia Climate Office, the 48 hour rain total of over 11 inches in Atlanta is the new record for a 2 day period, breaking a record by about 1.5 inches that has stood since 1886.

Anyway, the toll of Helene looks pretty horrible. The forecasts were incredibly precise and well done, but at a certain point, there is only so much you can do. We hope for the best for those impacted by Helene, particularly as a blog based in Houston which has seen plenty of flooding calamities.

Two other notes today before closing. First, Tropical Storm Joyce did indeed form from Invest 98L in the Atlantic. It is of no threat to land.

Second, the odds of development on the Caribbean area of interest next week remain at 30 percent. I continue to see two consistencies in the modeling with this one. First, most are capping this one's intensity. You will occasionally get a rogue GFS model run that churns out a strong hurricane, but for the most part, models have a substantially lower ceiling with this than they did with Helene at this point in its life cycle. That signals that perhaps this one has a chance to not be a huge ordeal. Secondly, they cannot agree on track at all. There's no theme of note here, with solutions running the gamut across the Gulf. I would contend that this is not one to lose sleep over right now. We'll assess things through the weekend and come back refreshed Sunday or Monday with the latest.

[DoctorMu]

The Central American Gyre will be yielding another Gulf Storm. I don't see a FROPA in SETX until Oct 10-14, but we will probably be protected by a Western Upper Level Ridge. The new TX is likely to target the northern to northeastern Gulf coast again. Louisiana - the Florida panhandle next weekend.

Having said that, there is absolutely no agreement among the models. But then we don't have initial conditions yet. Stay tuned just in case.

Hot/warm and dry until then locally.

[tireman4]

000
WTNT32 KNHC 300838
TCPAT2

BULLETIN
Tropical Depression Twelve Advisory Number 3
NWS National Hurricane Center Miami FL AL122024
500 AM AST Mon Sep 30 2024

...DEPRESSION NEAR TROPICAL STORM STRENGTH...
...EXPECTED TO BECOME A LARGE AND POWERFUL HURRICANE LATER THIS
WEEK...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...14.0N 34.1W
ABOUT 690 MI...1105 KM W OF THE CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Depression Twelve
was located near latitude 14.0 North, longitude 34.1 West. The
depression is moving toward the west near 8 mph (13 km/h), and a
general westward to west-northwestward motion is expected to
continue through Tuesday. A gradual turn to the northwest is
forecast by Wednesday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Steady strengthening is forecast, and the depression is likely to
become a hurricane by Tuesday night or Wednesday.

The estimated minimum central pressure is 1005 mb (29.68 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Hagen

[tireman4]

000
ABPZ20 KNHC 301153
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Sep 30 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Offshore of Southwestern Mexico:
An area of low pressure is expected to develop off the coast of
southwestern Mexico during the next day or so. After that time,
environmental conditions are expected to be generally conducive for
additional development, and a tropical depression is likely to form
by the middle or latter portions of this week. The disturbance is
forecast to meander near or just offshore the coast for much of the
week, and then begin moving slowly west-northwestward, parallel to
the coast of Mexico by this weekend. Regardless of development, this
system is expected to contribute to additional heavy rainfall across
portions of the southwestern coast of Mexico already adversely
affected by substantial rainfall last week, and interests there
should monitor the progress of this disturbance.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...70 percent.

South of the Gulf of Tehuantepec:
Another area of low pressure has developed in the Gulf of
Tehuantepec and is producing disorganized showers and thunderstorms
primarily offshore of southern Mexico. The system is forecast to
move erratically through mid-week before drifting northward towards
the southern Mexican coast, and some additional development of the
system is possible while it remains offshore. Regardless of
formation, heavy rain is possible along most of the coast of
southern Mexico and northern Central America throughout this week.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Papin

[tireman4]

Eastern Tropical Atlantic:
Showers and thunderstorms have increased in association with a
tropical wave located a few hundred miles south of the Cabo Verde
Islands. Upper-level winds are forecast to become more conducive
for gradual development, and a tropical depression is likely to form
in a few days while it moves slowly westward over the eastern
tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...80 percent.