Tropical Discussion 2025

[Scott747]

93l actually looks healthy all things considering and the center is beginning to dip a little sw as it makes its way across Florida.

Hurricane models suggested this since they started running. Main energy should stay to the n but if it does tug a little further she then it may make it a little further w.

Not enough to directly impact us except for perhaps the Golden Triangle. Might see some adjustments this evening.

[DoctorMu]

Still seeing a lot of retrograde flow in the Gulf...and movement of showers off the Gulf coast of Florida heading SW. The golden triangle is not a bad guess on Texas impacts. Just hoping it drifts our way for a few showers. The more disorganized the better.

Love the easterlies if they can be sustained. More Florida weather. A colleague who lived in Florida and I were discussing the more east coast/FL weather of late. Easterlies should also limit more Hill Country flooding. It's the EPAC moisture that crosses over the results in a deluge.

[DoctorMu]

Retrograde lemonade?

Forecast for LA. Don't count out some TX impacts.

[biggerbyte]

So there is no current model support for what I'm about to say. There is a possibility of a center relocation, if you want call it that tonight, much further southwest. Just thought I'd throw that out there.

[Rip76]

Retrograde lemonade?

Forecast for LA. Don't count out some TX impacts.

Retrograde Lemonade is a great band name.

[Stratton20]

Mid level center is over the water, id almost expect we are getting a reconnaissance flight sometime tommorow, given 93L’s small size, i wouldn’t be the least bit surprised if this organizes more than what the models see happening

[Ptarmigan]

Until something actually develops, everyone on the Gulf Coast should keep an eye on Invest 93L.

[tireman4]

As bad information on Invest 93L spreads, we lay it out straight, as well as look at Virginia flooding
One city has had 13 flash flood warnings and a flash flood emergency this month
The Eyewall and Matt Lanza
Jul 16






READ IN APP

In brief: Invest 93L is unlikely to develop much at all, but it remains a flooding risk for Louisiana heading toward Friday. We also take a closer look at flooding that has occurred in the Southside of Virginia, specifically near Petersburg.

Invest 93L
Before we begin on this disturbance, I am going to shout out a post at our Houston-focused site, Space City Weather. The amount of bad information on the northeast Gulf system that is coming from one specific source, TikTok, is almost incomprehensible. One of the main reasons our sites exist for Houston at SCW and here for others is to provide an honest forecast and information about weather from experts that are aligned with a mission of informing without being patronizing or condescending. When it's boring, we're boring. When things get interesting, we get interesting. We also want to make sure folks keep their eye on the ball. When it appears a storm is going to threaten southwest Florida and the media hasn't left Tampa, we want to highlight that. When a storm is a flooding threat and has no realistic chance of becoming a hurricane, we want to focus on that. So, thanks for reading, please keep spreading the word, and if you feel compelled or able, upgrade to a paid subscription to further support our work.

This Substack is reader-supported. To receive new posts and support our work, consider becoming a free or paid subscriber.

Upgrade to paid
Invest 93L did a good thing yesterday, coming off the Florida Peninsula farther north than expected. This will keep it closer to land and probably keep it from developing much, if at all.


Gulf satellite image showing Invest 93L in the northeast, very disorganized but producing some heavy thunderstorms. (Tropical Tidbits)
It's not really possible to pick out a true "center" on the satellite image, but it's somewhere near or south of Panama City. Intensity-wise, the forecast for 93L is pretty straightforward. The majority of modeling including the "corrected consensus approach" product that has had significant success in recent years keep this barely a tropical depression. Very few models bring 93L to tropical storm intensity. The NHC odds have held steady at 40%.

Let's talk rainfall, because that will continue to be the primary story here.


A moderate risk (3/4) exists for flash flooding in Louisiana on Friday. (NOAA WPC)
A moderate risk of excessive rainfall exists by Friday in Louisiana. The flash flood risk here seems a little less scary today, but it's nevertheless serious.


Rain totals through Monday morning should be on the order of 3 to 6 inches across much of Louisiana which could cause flooding. (Pivotal Weather)
The total rainfall forecasts seem to have backed off a little, now down to 3 to 6 inches across much of southern Louisiana for this event. Still, that may cause flooding and with locally higher amounts, locally more significant flooding remains a concern, primarily between tomorrow evening and Saturday. 93L should basically dissipate and get absorbed into the broader weather pattern over the Southeast once again by next week.

The Virginia Southside flooded multiple times
It's been a rough week just outside of Richmond, Virginia. Petersburg has been under 13 flash flood warnings this month. It finally broke yesterday with flash flood emergencies, significant flooding, a state of emergency, and a lot of frustration about systemic neglect of mitigation measures.


7 inches of rain more than usual have fallen so far this month in Petersburg, Virginia. (High Plains Regional Climate Center)
Some parts of the Southside of Virginia have seen north of 10 to 12 inches of rain this month, and it's taken a toll.


Rainfall so far this month south of Richmond and in the Petersburg and Colonial Heights areas has been remarkable. (NOAA)
For more reading on the problems in Petersburg, I'd suggest this from the Virginia Mercury.

More on this event from WRIC in Richmond as well.

And some food for thought here: The problems in Petersburg are a microcosm of the problems facing hundreds of cities in this country. Many are plagued by poor drainage during heavy rain and backlogs of projects that would help ease the problems. The cost to get these projects across the finish line would be astronomical, and with a moving target (heavier rainfall rates as the climate warms), there's no guarantee that even funding the wish lists of every community would lead to a successful outcome.

[DoctorMu]

Hurricane models see inroads of 93L/Dexter to east of I-45. Not unreasonable.

[tireman4]

Levi Cowan

[tireman4]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Wed Jul 16 2025

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

Northeastern and north-central Gulf (AL93):
Surface and radar observations indicate that a westward-moving
broad area of low pressure is located along the coast of the
Florida Panhandle near Panama City. The associated shower and
thunderstorm activity remains disorganized and located mainly south
and southwest of the center. This system is forecast to continue
moving westward across the northern portion of the Gulf through
tonight, reaching the coast of Louisiana by Thursday. If this system
moves far enough offshore, environmental conditions over the Gulf
appear generally favorable for additional development, and a
tropical depression could form over the next day or two before
the system moves fully inland by the end of the week.

Regardless of development, heavy rainfall could produce localized
flash flooding over portions of Florida through through today.
Heavy rainfall could also cause flash flooding for portions of the
north-central Gulf Coast beginning late today and continuing through
Friday. For additional information, please refer to products issued
by the Weather Prediction Center and your local National Weather
Service office.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...40 percent.

$$
Forecaster Beven

[DoctorMu]

I-45 and east is going to see some rain tomorrow evening and Friday. [Cajun accent] Ah gahrohn-tee!

https://www.star.nesdis.noaa.gov/goes/s ... &length=24

[Stratton20]

GFS, Euro/ CMC all have 93L going inland and making one gigantic loop back into the gulf again in a week and getting pushed west again, 93L might be around the gulf coast for quite some time

[tireman4]

In brief: Invest 93L is almost out of time as it transitions into exclusively a flooding concern for parts of Louisiana. The tropics may pick up some activity toward later July. And there are growing signs that the end of July may end on a very hot note over much of the country.

Invest 93L
In terms of development, Invest 93L is approaching the end of the road. It seems unlikely that it will get a name, and it probably won't become a depression either. There's a lot of rain moving into far southern Louisiana this morning.


Rainfall is moving across south and east Louisiana this morning, as seen on radar at 7:45 CT. (NOAA NSSL)
Given the current storm situation there, it would appear that several rounds of locally heavy rain are likely to push in through today and into tomorrow. The entire southern half of Louisiana is under a flash flood watch today, stretching from Lake Charles to New Orleans. The moderate risk for flash flooding (level 3/4) has moved into today and is focused primarily on the Atchafalaya.


A moderate risk for flash flooding today (level 3/4) for Lafayette and much of Acadiana. (NOAA WPC)
While the expected rainfall totals today won't be overwhelming (probably on the order of 2 to 4 inches or some higher amounts), the rate of rain may be enough to cause some locally significant flash flooding. Should 93L slow down a good bit further as well, that would serve to enhance localized rainfall risks. More rain and thunderstorms are likely tomorrow as well.


Rainfall totals expected across Louisiana through the weekend. Consider these values an average, where some places may see higher amounts and others lower amounts. (Pivotal Weather)
All told about 2 to 5 inches on average should be expected the next couple days. I would not be the least bit shocked if one or two spots did pick up as much as 6 to 9 inches of rain, but those would the exception rather than the rule I think. Overall, the flooding risks look a little less ominous than they did earlier this week, but they should not be discounted.

This Substack is reader-supported. To receive new posts and support our work, consider becoming a free or paid subscriber.

Upgrade to paid
Rest of the Atlantic
While most of Atlantic hurricane season thus far has been quiet, there may be some changes brewing heading into late July and early August. I want to note this because I also think some of these changes may be somewhat overhyped in some circles. It's not as if the Atlantic pattern will suddenly turn very favorable. It will, however, turn less hostile.


The background state of the atmosphere will become somewhat less hostile as we close July across the Atlantic, but there's no guarantee that means anything just yet. (StormVista)
From the plot above, you can see that the background state of the atmosphere is expected to work into more favorable territory by the time we get to next week across the Atlantic basin. However, it's still sort of lacking a lot of teeth. I'm just not convinced of this being the catalyst to bring us big activity yet. However, this is the first assault on the wall of unfavorability that has gripped the basin since early to mid-June.


Meager probabilities of tropical cyclone activity are forecast in the Atlantic heading into the end of July and early August from the ECMWF subseasonal model. (ECMWF)
The European weekly model is not having any of it, though, going with very low probabilities off the East Coast to close July.

Right now, I see a pathway to a more active Atlantic, but I don't see concrete evidence that it's definitely coming. So for now we'll just keep monitoring things.

Heat wave on the way?
When it comes to forecasting different weather variables, some end up better to forecast than others at longer lead times. Hurricane tracks at 10 to 15 days out? Probably poor! Total precipitation 10 to 15 days out? Probably a bad forecast. Will it be wetter or drier than normal? That's a slightly higher confidence forecast depending on each weather pattern. How about heat waves? Well, let's discuss that today.

There have been some signals in the models over the last couple days for an expanding ridge of high pressure across the middle of the country in the 10 to 15 day forecast period. Yesterday afternoon, NOAA's Climate Prediction Center added the risk of "extreme heat" to their forecast for July 24th through the 30th across a broad expanse of the country from the central Plains into the Southeast.


The Climate Prediction Center is calling for the potential of continued flooding risk in the South, as well as potentially extreme heat in much of the eastern half of the country to close July. (NOAA CPC)
When we look at the broad weather pattern that is forecast from the European ensemble mean, an average of 51 ensemble members to produce a forecast for the 11 to 15 day period, you can see that there is a very strong signal for above average heights in the upper atmosphere, a signal for hot weather.


A significant ridge of high pressure may evolve over the Plains to close July, leading to a substantial heat wave across much of the country. (Tropical Tidbits)
In fact, if you look at the potential for annual record 500 mb heights, or how many of the ensemble members are predicting that the intensity of the ridge will break all-time records, somewhere in the range of 20 to 30 percent of the European ensemble members are calling for just that. That's a very impressive signal at this lead time.


Roughly 20 to 30 percent of European ensemble members are forecasting record heights in the atmosphere over the Plains at the end of July, which indicates a strong chance for a significant heat wave. (Tomer Burg/PolarWx)
Now, the Euro has been wrong before at this lead time. In fact, even a couple times this year it's overestimated the heat somewhat. However, this is a slightly different scale and setup, and it has additional support from the 51 member European AI model ensemble as well. Record or not, it appears that there will be a significant bout of summer heat coming again in the day 10 to 15 timeframe as we head toward August. More to come on this.

Flooding notes: Is Waco, Texas prone to destructive flooding?
Just want to close today with a shoutout to the Waco Bridge, a new independent news site covering Waco, TX. They put together a nice piece yesterday that discusses the flood risk specific to the city of Waco. While there have been historic floods there in the past, a number of engineering projects over the last 50 to 75 years have dramatically lowered the risk of a catastrophic flood there. Not to say serious, if not destructive flooding cannot happen; it can happen virtually anywhere in this country. But there has been risk reduction. I know we have a number of Texas readers, so this may be a good story to share with any friends or family in the Waco area. There are also a number of good links in there for some real-time and forecast flooding data from across Texas.

Periodically, I will effort to point out stories from local news sources from around the country that touch on localized flooding risk or risk of other weather-related vulnerabilities.

[tireman4]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Thu Jul 17 2025

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

Northern Gulf Coast (AL93):
Satellite, surface, and radar data indicate that the broad low
pressure area over northern Gulf is located just south of the coast
of Mississippi. The associated shower and thunderstorm activity
remains disorganized and located mainly to the west and southwest
of the center. Some development could occur before the system moves
westward into Louisiana later today or tonight, although the
chances of the system developing into a tropical depression are low.

Regardless of development, heavy rainfall could produce localized
flash flooding over portions of the north-central Gulf Coast through
Friday. For additional information, please refer to products issued
by the Weather Prediction Center and your local National Weather
Service office.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...low...30 percent.

$$
Forecaster Beven

[Stratton20]

GFS/ Euro/ CMC all loop 93L around in the gulf again next week and bring more tropical moisture this way , also keep the big ridge far enough to our north to allow 93L ( part 2) to head toward texas

[tireman4]

315
ABNT20 KNHC 171733
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Jul 17 2025

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

Northern Gulf Coast and Southeastern Louisiana (AL93):
Satellite, surface, and radar data indicate that the broad low
pressure area is moving inland over southeastern Louisiana, and
that the associated shower and thunderstorm activity remains
disorganized and located mainly to the west and southwest
of the center. Little development is expected while the center
remains near the coast this afternoon and tonight, and the system
is expected to weaken as it moves farther inland on Friday.

Regardless of development, heavy rainfall could produce localized
flash flooding over portions of the north-central Gulf Coast through
Friday. For additional information, please refer to products issued
by the Weather Prediction Center and your local National Weather
Service office.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

$$
Forecaster Beven

[DoctorMu]

Hurricane models see inroads of 93L/Dexter to east of I-45. Not unreasonable.

Things are going as expected with a few showers attempting to spread west of Huntsville. A maybe on Houston before dry air sneaks in from the south tonight from the Gulf.

[Cpv17]

The door will be open late July into the beginning of August for a storm into Texas.

[Stratton20]

Cpv17 bingo, and gotta watch next week with the remnants of 93L getting back over the gulf, looks like possibly further south in the gulf so something to watch, GFS briefly tries to close off a weak low before koving into texas, but honestly you make a good point, look at the ridge placement over the central YS even beyond next week, thats an ideal location for the ridge to steer tropical mischief right into texas