More flash flooding to discuss as we gloss over some middling tropical disturbances

In brief: A couple areas to watch in the tropics seem unlikely to develop much. Flash flooding hit just outside of DC yesterday and in Iowa overnight. The main flooding threat today will be across central Illinois, Indiana, and southwest Ohio.

Central Atlantic wave not a threat to land

The National Hurricane Center continues with a tropical wave highlighted on their outlook map this morning, but odds of development have fallen to 10 percent. This appears to be unlikely to do much of anything at this point.

The Central Atlantic disturbance is struggling to organize this weekend. (Weathernerds.org)

It’s just not in a prime spot for development, and it’s quite a bit far south. So ultimately, this will likely meet its demise before arriving in the Caribbean as it encounters strong wind shear. Perhaps we’ll see some increased shower chances for some of the Lesser Antilles, but that would be all.

Gulf disturbance next week

Models continue to show that the remnants of 93L will reorient into a new disturbance and do a very similar thing to Invest 93L. A true meteorological deja vu. The new disturbance should emerge in the Gulf by about midweek this coming week. It will then likely track close to the Gulf Coast toward Louisiana or even Texas before coming ashore.

Another Gulf disturbance may make some noise but will ultimately probably move ashore as a rainmaker. (Tropical Tidbits)

Because of how close this will again be to land, it seems highly unlikely that it would develop. Again. Still, this may produce another round of locally heavy rain for the central and eastern Gulf Coast, which you can again see on the rainfall forecast map from the NWS for the next 7 days.

More heavy rain is likely in spots on the Gulf Coast this coming week as another tropical disturbance (unlikely to develop) will produce downpours. (Pivotal Weather)

Certainly something to keep an eye on, but this once again seems like a rain event more than anything.

Flash flood emergency outside of DC on Saturday

The latest in a spate of flash flood emergencies this month occurred in Montgomery County, Maryland, just outside of DC on Saturday afternoon. Rainfall totals of 3 to 4 inches or more, much of which fell in a short time led to widespread significant flooding in the area.

Rain totals north of 4 inches likely fell next door to Silver Spring, MD yesterday, as heavy rain triggered a flash flood emergency. (NOAA MRMS)

Some of the pictures are certainly a bit scary for this area. The runoff caused a very rapid rise on Sligo Creek, which runs through Takoma Park and dumps into the Anacostia River near Hyattsville. The creek set a new record, though it appears that its records only date back into the early 2000s.

Sligo Creek reached a record crest near Takoma Park, though records only date back into the earlier part of this century. (NOAA)

But again, notice the rapid rise there. In a little more than an hour, the creek went from about 20 cfs to 3,000 cfs and rose 7 feet. And while this was certainly a heavy rainfall, it was not the heaviest we’ve ever seen in this region. It just speaks to how quickly flash flooding can overwhelm drainage and watersheds.

Rain chances today

A number of flash flood warnings are currently in effect across Iowa where heavy rain fell overnight to the tune of 3 to 6 inches south of Des Moines.

Rain totals overnight in Iowa exceeded 2-3 inches in many spots with areas south of Des Moines seeing as much as 5 to 6 inches. (NOAA MRMS)

Those thunderstorms have now pushed into Illinois, and as the day goes on, we could see heavy storms develop with daytime heating across Central Illinois and Indiana. A moderate risk (level 3 of 4) for excessive rain is in place from about Terre Haute, Indiana through Springfield and Decatur over to Quincy, Illinois.

(NOAA WPC)

While flash flooding may not be as widespread as it was in Iowa, it does look like we could see isolated pockets from northern Missouri into the Indianapolis, Cincinnati, or Louisville areas that see anywhere from 3 to 5 inches of rain later today. This could produce rapid onset flash flooding in spots. It’s a good day to be alert if you live there or your travels take you to those areas.

You can see the combination of a building heat wave (extreme heat warnings in effect in Kansas and Missouri south to near Memphis) bumping up against flooding risks (green indicating flood watches) in the Midwest. A very hot, swampy type situation for much of the middle of the country today.

(Pivotal Weather)

Heat advisories ring the Southeast today from Oklahoma, Arkansas, and Louisiana, along the Gulf Coast to Florida and up into eastern North Carolina. Expect to see advisories and excessive heat messaging for the next 7 to 10 days across much of the country.

Tropics not totally asleep, as we focus on an extended duration heat wave beginning next week for the Midwest and Mid-South

In brief: A disturbance in the Central Atlantic may try to develop before it dissipates near the Caribbean. Former Invest 93L may return to the Gulf next week as a new disturbance, but no signs of development are showing yet. More flooding concerns continue today in the Midwest and Mid-Atlantic. And some stronger than normal heat remains in the cards next week and into August.

Tropical Atlantic

Yesterday we mentioned the possibility of something low-end in the open Atlantic, and today we’ve got a lemon showing up on the National Hurricane Center outlook.

A disturbance with a 20 percent chance of developing is moving across the Central Atlantic. (NOAA NHC)

This one has about a 20 percent shot at development before it runs into a wall of wind shear in the Caribbean next week. Currently, it’s not a whole heck of a lot to look at. It’s a very broad area of thunderstorms from about 29W to 48W, with the primary disturbance to watch around 36W.

Within a broad area of thunderstorms lies the disturbance being monitored for a low chance of development. (Weathernerds.org)

Wind shear is pretty relaxed out there right now, which could help it to develop, but there is a bunch of dry air and Saharan dust lying just north of this axis of thunderstorms. I would assume if this did develop, as a handful of various models show, it would be brief and lower-end. Semi-permanent high wind shear awaits this once it gets near the islands however, which should spell the end of the road for whatever it can become out there. Perhaps we’ll get an Invest out of this today or tomorrow though, so we’ll just keep an eye on it. But for now, this should not be a worry for anyone.

Ex-Invest 93L’s circle of life

The artist formerly known as Invest 93L is just going to meander around the Southeast this weekend and early next week. Eventually it’s going to be forced south again toward the Gulf and it could re-emerge around late week, likely as a new disturbance. There’s a fair bit of uncertainty as to exactly where this shows back up and in what shape it would be.

Broad signal for a tropical disturbance to re-emerge in the northeast Gulf next week, but not a lot of data suggests it will progress beyond a rain threat right now. (Tropical Tidbits)

But at this time, there’s not any real reliable data showing development. For now, it’s mostly just a curiosity that could bring more rain to parts of the Gulf Coast between Texas and Florida by later next week. Still, we’ll keep tabs on it.

Flooding concerns continue

We saw an interesting assortment of weather on Friday, including a funky, odd system tracking east to west across Southern California bringing some flash flood warnings to the region. MCV’s (or a Mesoscale Convective Vortex) are not especially large, but they can bring some localized intense rainfall to an area as they pass through.

There’s something you don’t see every day — an MCV moving east to west into California towards the Death Valley region:

— Tomer Burg (@burgwx.bsky.social) 2025-07-18T13:48:18.720Z

In fact, we saw some heavy rain in spots between Death Valley (yes it does rain there!) southwest into the San Gabriel and San Bernardino Mountains. There was also a pocket of heavy rain near the Castle Mountains south of I-15 in the Mojave Desert as well.

Rain totals based on radar estimates across Southern California yesterday. (NOAA NSSL)

Additional heavy rain fell in other parts of the Southwest, as it has the last few days, with the area north and west of Las Vegas cashing in, as well as much of southwest Utah and northern Arizona, as well as New Mexico. Given the dry winter this past year in this region, rainfall is certainly welcome.

There were also additional flooding issues in other parts of the country as well, including Evansville, Indiana and (again) Petersburg, Virginia, which had another flash flood warning yesterday.

A broad area of slight flooding risk (2/4) exists from Iowa through the Ohio Valley and into the Mid-Atlantic today. (NOAA WPC)

A slight risk (2/4) is in place over a wide swath of the country for flooding today, covering Iowa, most of the Midwest, and the Mid-Atlantic.

Heat wave cometh

We continue to see plenty of signs of a stout, long-duration heat wave establishing this upcoming week into the following week across much of the Midwest and Mid-South. There aren’t a whole lot of record highs being forecast yet, but there are a number of warm minimum temperature records being forecast. Models continue to indicate some risk of near-record strength to this ridge as it builds.

(NOAA WPC)

Regardless of anything, a wide area is expected to see risk for extreme heat next week and into the beginning of August. Numerous pockets of “extreme” heat risk from the newer NWS product that factors in other things besides just temperature show up by next Thursday and Friday (shown below).

Extreme heat risk is showing up in parts of Mississippi, Arkansas, Tennessee, and elsewhere by late next week. (NOAA)

The combination of these heat risk maps and wet-bulb globe temperatures reaching extreme values in spots means that the heat precautions will be necessary, particularly for vulnerable communities across the Midwest and Mid-South next week. Stay tuned.

Flooding concerns for Louisiana, Virginia, Indiana as heat wave odds increase to close July

In brief: Invest 93L is ashore and not a development risk, bringing more rain and flooding risk to Louisiana and the Gulf Coast. More non-tropical flooding concerns exist today in Virginia and tomorrow in Indiana. And an end of the month heat wave for the Plains, Midwest, and Southeast is looking more and more likely.

Invest 93L: RIP

Shout out to all the purveyors of doom on social media (including some professional meteorologists!) that just had to hype up Invest 93L into something it would never be. Development odds are down to zero percent this morning because the system is over Louisiana now. It’s dead, Jim.

That said, it’s not exactly dead dead. It’s still producing rain, and it remains at least a slight flooding risk (2/4) for much of Louisiana, extreme East Texas, and parts of the Gulf Coast.

A slight risk for heavy rain and flooding exists from Beaumont, TX east across most of Louisiana to the Florida Panhandle today. (NOAA WPC)

There have certainly been some locally impressive rainfall totals in Louisiana, including just shy of 10 inches in the last couple days in St. Charles Parish.

A sampling of 48-hour rainfall totals in Louisiana including nearly 8 inches just north of Morgan City, over 6 inches in New Orleans East, and nearly 10 inches in St. Charles Parish. (NOAA)

I have not seen any reports of major flooding, so that’s good. But let’s see how today unfolds. Some models are still a bit cheeky with rainfall totals in a few spots today, so never declare victory until the storm is officially over.

Rest of the tropics

It looks pretty quiet over the next few days. It is possible that we see something low-end and brief in the open Atlantic early next week, but there aren’t currently any land threats. It’s also possible that the remnants of 93L do a loop around the Southeast and re-emerge again in the Gulf later next week. I’d say that’s something to watch, but much like this week, proximity to land may hinder any development chances.

Flooding risk du jour

If you had northern Virginia on your Summer 2025 flooding Bingo card, congrats, and don’t forget the free space.

A moderate risk (3/4) is in place for the northern Shenandoah Valley in Virginia today for flooding. (NOAA WPC)

Parts of the northern Shenandoah Valley have seen 200 percent of normal rainfall so far this month, with some places seeing as much as 4 to 8 inches of rain since the start of the month. Heavy showers and storms are possible there later today, and this would be a definite area to watch for flooding today. A broad area of slight risk (2/4) surrounds that extending into parts of the Ohio Valley and south into Hampton Roads and the Outer Banks.

Flooding risk du jour Saturday

Tomorrow, I would watch Indiana closest. There is some modeling showing as much as 3 to 6 inches possible, mostly tomorrow in that area. Southern Indiana has seen anywhere from 4 to 8 inches of rain this month as well.

The SPC’s HREF model flagging some significant rain potential in southern Indiana on Saturday. (NOAA SPC)

The HREF model in particular is a little excited about potential heavy rain. The probability matched mean product above suggests that rain amounts of 3 to 6 inches will be possible tomorrow in the heaviest storms mainly south of I-70 in Indiana. I’d pay particularly close attention in the Bloomington through Louisville corridor on Saturday.

Additional rain may follow Sunday and Monday, and flooding risk remains in place there.

Heat wave update

The European ensemble model continues to indicate a decent risk of a record strong ridge of high pressure in the upper atmosphere over the Plains in about 10 days or so.

The percentage of European ensemble members indicating a record strong ridge of high pressure is now up above 30 percent near New Mexico and the Texas and Oklahoma Panhandles. (Polarwx.com)

The Climate Prediction Center continues to indicate a risk of extreme heat starting around July 25th and continuing through the end of the month. There is also now some potential for drought to begin developing and expanding in parts of Kansas.

Odds continue to grow that a significant heat wave will impact the Plains, Midwest, and parts of the Southeast to close July. (NOAA CPC)

Overall, it appears the end of the month may be more about heat than flooding. But we will see.

Invest 93L remains a flooding concern in Louisiana. Plus, signs of the next big heat wave are showing up

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.

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.