Tropical Atlantic splattered with areas to watch, as Tropical Storm Dexter begins to escape out to sea

In brief: There are three items in the Atlantic today. Dexter is heading out to sea. A low pressure system may develop off the Carolina coast this week, keeping wet weather in play for the Southeast. A third area emerging off Africa this week has some chance to develop, but it’s getting one model with a poor track record excited.

Atlantic tropics

We have our fourth storm of the hurricane season today, thankfully not a threat to land. We’ve also got some other business to attend to in the basin. So, let’s get started.

Tropical Storm Dexter

(NOAA/NHC)

Invest 95L became Tropical Storm Dexter late yesterday. Dexter is already exiting stage right, moving east northeast around 10 to 15 mph. By the end of the week, Dexter should be post-tropical. Eventually, this will probably end up in the British Isles, either as part of another typical European storm or as a passing disturbance. Either way, it’s mostly just a curiosity than anything else.

Satellite image from Monday morning showing Dexter and a ton of wildfire smoke across the Northeast and Great Lakes. (College of DuPage)

Deep Atlantic area of interest

(NOAA/NHC)

A tropical wave emerging off Africa today carries a 50/50 chance of developing as it moves into the open Atlantic this week. Currently, there is little to see with this tropical wave, as it’s basically producing no shower or storm activity. However, by the time we get to later Tuesday or Wednesday, we do expect this thing to fire up some. From there, model guidance is in good agreement on decent odds of development. The European ensemble is probably the most bulled up about this one (see below), but the various AI modeling and ensembles also support development.

A small majority of the European ensemble supports development of a tropical wave off the coast of Africa by later this week or weekend. (Weathernerds.org)

Some GFS operational model runs have gotten a bit spicy with this, keeping it middling into next week before trying to push it due west toward the Southeast as a strengthening system. There’s not a whole lot of additional support for this scenario, so the GFS appears to be an outlier in this regard. The reason it seems to be doing this is similar to what we described in yesterday’s post, about a “weakness” in the ridge over the Atlantic that would allow the system to turn north and exit. The GFS keeps the system fairly weak, which would make it a little less likely to turn north into the weakness and out to sea. Then, as the system it strengthens, it rebuilds the ridge to the north, basically forcing it to continue due west or northwest toward the Southeast.

The timing of this diversion from the overall consensus view of out to sea seems to be in the Sunday through Tuesday timeframe, so we’ll get a fairly quick resolution to this through the week as the overarching weather pattern clears up. I suspect we’ll have a good idea if this is an actual Southeast concern as the GFS operational suggests by midweek. Historically, the GFS does not have a good track record when going it alone in scenarios like this, so we’ll keep an eye on it but we’re far from being concerned about it at this time.

Closer to home

Meanwhile, a newer 30 percent area got drawn yesterday afternoon off the Southeast coast.

(NOAA/NHC)

Behind Dexter there is still a remnant stationary front off the coast of the Southeast. Over the next few days, we’re probably going to see a weak area of low pressure develop along that remnant boundary. Unlike Dexter, this won’t get whisked out to sea. Rather, it looks likely to just kind of sit and spin for a bit.

Friday’s forecast map from NOAA shows weak low pressure off the South Carolina coast. (NOAA WPC)

To be honest, I’m not super concerned about significant development here. However, this may make for a somewhat dreary week along the Carolina coast. Rain totals may begin to add up some in this area as well through the week.

It looks like a wet week for Georgia and South Carolina, as well as parts of North Florida. (Pivotal Weather)

So overall this is worth keeping tabs on, but it is probably not a serious concern.

There’s more to discuss non-tropics, but we’ll save that for later or tomorrow.

The Atlantic is slowly warming up, while the Desert Southwest is going to heat up this week

In brief: The Atlantic tropics are getting a little busier, but at present none of the potential systems are a concern for land. Meanwhile, the Desert Southwest is going to be at the center of a heat wave this week, which means some extreme temperatures and continued high wildfire danger.

Tropics: Busier but within the realm of what’s typical for August

We’ll start in the Atlantic today. We’ve got two areas highlighted by the National Hurricane Center.

Two areas of interest, including one invest on the board today. (NOAA NHC)

Let’s start closer to the U.S.

Invest 95L

The disturbance we had thought might be of most interest through next week is trying to get its act together off the Carolinas. Invest 95L is attempting to look the part this morning.

Invest 95L is due east of the Outer Banks. It may develop into a tropical or subtropical system before exiting tomorrow. (Weathernerds.org)

Invest 95L is expected to pretty steadily work east-northeast and out to sea. Modeling is in good agreement that this will exit stage right quickly.

Various AI ensembles and the traditional European ensemble all agree that this will quickly turn out to sea. (Google Weather Lab)

Conditions for development should become rather hostile over the next couple days, so this will probably succumb to environmental conditions eventually as it moves out to sea. Bottom line: Decent chance to develop; no threat to land.

Broad 30% area of interest

Looking out farther into the Atlantic today, a very large 30% area has been drawn that covers almost the entire central Atlantic. There’s not a whole lot doing out there at the moment, but it appears that a wave will exit Africa and may begin to attempt to develop by mid to late week. When we look at the European model ensemble picture, we can see that the majority of the 51 ensemble members are doing something out there by later this week, but since they can’t exactly resolve where that might occur, the area of possible interest is rather sprawling.

A large area of possible slow development later this week in the open Atlantic. (Weathernerds.org)

The overall pattern in the Atlantic this week will feature a pretty broad “weakness” in the subtropical ridge east of Bermuda. This should allow for any sort of developing storm to exit. A weaker, disorganized wave may just plod along west northwest.

Friday’s upper air weather pattern probably is conducive to a system moving more NW than W in the Atlantic. (Tropical Tidbits)

You never like to overthink these things too much, so it seems pretty simple. That said, if the forecast weakness ends up stronger or less impactful than predicted today, that could change the overall profile of risk with this wave. For now, it’s probably not a concern for land, but it’s probably also a good idea to monitor its progress later this week.

Behind that, there’s no real defined risk that I can pick up on over the next 2 weeks, but it’s the time of year to keep watching, as I’m sure something will materialize at some point. For now though, the takeaway is that the Atlantic is becoming more active but within the bounds of what’s normal for this time of year.

A Desert Southwest heat wave

The weather pattern has calmed a bit lately, with more moderate temperatures a bit less in the way of extreme rain and such. That said, it does look like the heat is going to crank up this week. When you’re talking about possible temperature records in the Desert Southwest, you know it’s hot. High pressure is going to flex its muscles in that region this week, and in fact, the percentage of European ensemble members showing an all-time record strong upper level high pressure system is well up over 50 to 75 percent this coming week (Wednesday).

The Desert Southwest is going to be a blast furnace this week. (Polarwx.com)

That doesn’t guarantee that we’ll see a record, but it sure suggests that whatever this is is going to be extreme. In fact, we’re already seeing numerous record highs or near record highs being forecast in the Desert. Phoenix is expected to hit 117° on Thursday, which would break a daily record by 5 degrees and match the all-time August record high temperature last set in late August 2023.

Several record high temperatures are forecast to be approached or exceeded this week in the Desert Southwest, with Thursday shown here. (NOAA)

The 111° is Tucson is only one degree shy of the August record as well.

We may see more than one record fall this week in Phoenix and Tucson.

Forecast temperatures for the next 7 days in Phoenix. (Weather Bell)

Broadly, the Southwest will also experience multiple days of records threatened. More importantly, it looks dry this week with most moisture limited. Any rain will be limited to the Plains or perhaps deep into Mexico.

Rainfall over the next 7 days is expected to be virtually non-existent in the Southwest. (StormVista Weather Models)

This will likely lead to continuing wildfire concerns, and critical fire danger is forecast for Utah tomorrow and Tuesday. Red Flag Warnings are already posted for both days.

Several wildfires, including the now 60,000 acre Monroe Canyon fire are burning throughout Utah, a situation that may worsen some Monday and Tuesday. (State of Utah)

Conditions may be a little less extreme in Arizona for wildfires, but it’s possible that Red Flag Warnings are hoisted there too this week. Either way, the West is already a bit of a tinderbox, and this week will do nothing to help that situation.

More heat to open August, while we look back at July’s variable rainfall story across the country

In brief: Today we discuss the have too much’s and have too little’s of rainfall from July. We also briefly look at July’s temperatures. Meanwhile, August will begin quiet in the Atlantic, noisy in the Pacific, and just hot for many.

Recapping July’s rainfall

Apologies for some of the later day posts this week. Work obligations just take priority! Let’s look back at July real quick.

Despite all the flash flooding issues in July, the country saw a mixed bag overall, with the Southeast and New England generally drier than normal. The Southwest is a little choppier due to low average rainfall totals. (High Plains Regional Climate Center)

The areas that saw the most rainfall relative to normal last month included northern California and eastern Oregon, as well as the northern Rockies, Iowa, northern Missouri, Central Texas, and North Carolina and Virginia. Even with above normal rainfall in Oregon, some significant wildfires occurred there in July. Mount Shasta in California had its 5th wettest July on record.

Working east, it was the 7th wettest July on record in Glasgow, Montana and Norfolk, Nebraska. In Des Moines, Iowa July 2025 is the new wettest July on record. The capital of Iowa saw 10.62 inches of rain last month, just edging out July 1958.

Click to enlarge to see a number of rivers in Iowa that are near or in flood at present. (NOAA National Water Center)

Numerous rivers are in flood or near flood across Iowa after such a wet month. Waterloo, Iowa had their 7th wettest July, while Moline, Illinois finished in 5th place. Kansas City ended up in 9th place.

In Texas, Austin finished 9th for July in precip. Obviously some parts of Hill Country likely finished higher than that, not just because of the July 4th tragedy but because it was a wet month overall. In Waco, it was the 7th wettest July. Moving east, Richmond, Virginia had their 8th wettest July, while Greensboro, North Carolina finished in 9th place.

On the opposite end of the spectrum, it was the 11th driest July on record in Manchester, NH, while it was the 4th driest July in Bangor, Maine. Meanwhile, in Seattle it was the 6th driest July on record with a mere 0.01″ of rainfall. Not that July is known to be a wet month in Seattle, but the average is still about 0.6 inches. In Eugene, OR July 2025 joined 12 other Julys with no rainfall back to 1893.

Phoenix saw less than a quarter-inch of rain last month, and Las Vegas only saw about 0.02 inches. The first megafire of 2025 in the Lower 48 is ongoing in Arizona. Typically, Phoenix and Vegas pick up about a half-inch to an inch of rainfall, less north, more south due to the monsoon. With a somewhat sluggish July in the precip department in Arizona, Utah, and Nevada, we are seeing wildfire issues instead. The Dragon Bravo fire has burned over 115,000 acres and is continuing to expand. This fire is responsible for the terrible damage earlier this month in the North Rim of the Grand Canyon.

The Dragon Bravo fire on satellite imagery from this past Wednesday in northern Arizona. The Monroe Canyon fire in Utah can be seen near the top of the image. (College of DuPage)

Farther north, the Monroe Canyon fire is burning in Utah over 55,000 acres so far. This one appears to be growing significantly and has forced evacuations recently.

As far as heat goes, that’s a topic that we’ll perhaps dive into a little more on another day. But suffice to say, it was a hot month nationally.

Only Central & Western Texas and the Southwest were slightly below normal in July. The rest of the country was near or above normal, with much above normal in the Ohio Valley and Appalachia. (High Plains Regional Climate Center)

For Indianapolis, it was the hottest July since 2012. It was 10th hottest on record in Pittsburgh. In Syracuse, it was the third top 10 hottest summer since 2020.

Dog days of summer are here

Anyway, onto August we go.

Heat will be the main story for the beginning third of August. (NOAA WPC)

The main weather issue over the next 10 days or so will be heat. Yes, there will be pockets of strong storms and flooding around, but heat is going to begin to expand again next week from the Southwest into the Plains with a major ridge of high pressure setting up shop. We’ll probably see record temperatures at times from Arizona through Texas next week. August being August.

Tropical update

The tropics remain calm for now. I suspect we’ll have more to discuss next week. The Pacific is a beehive of activity, but none of these storms are likely to impact land at this time. Iona is heading deeper into the open Pacific and weakening. Gil should briefly become a hurricane before weakening as it passes well north of Hawaii.

The Pacific is buzzing. (NOAA NHC)

The area behind Gil could become a little more interesting to watch as it relates to Hawaii, but that’s days away so it’s more likely to do nothing than impact Hawaii at this time. We’ll keep an eye on things.

Mid-Atlantic flooding risk dialed in for today, while we peep the first half of August in the tropical Atlantic

In brief: A moderate risk (3/4) remains posted today for flooding between Washington, DC and northern New Jersey with isolated 4-to-7-inch totals expected. The tropics remain quiet, and heading into the first half of August, it’s not apparent that things are going to dramatically increase. We’ll keep watching.

Fairly brief update today, but let’s get to it.

Flooding risk in the Mid-Atlantic

There continues to be a moderate risk (3/4) of flooding today in the Mid-Atlantic region.

A moderate risk for excessive rainfall exists from just south of DC to just west of New York. (NOAA WPC)

Modeling continues to strongly suggest the potential for isolated pockets of 4 to 5 inches or more of rainfall across the moderate risk area. Potential does exist for perhaps up to 7 inches of rain in some really isolated spots. Many areas will be fine today, but the entire region is at risk for something a little more serious, hence the moderate risk.

HREF model probability-matched mean rainfall forecast for Thursday showing pockets of high rainfall. (NOAA SPC)

Basically, it’s a good day to make sure that you plan around the rain in the region. Maybe hang tight at your location for a bit if it’s raining heavily. Have a way to receive flash flood warnings. And do your best to never drive through a flooded road, as the water is often deeper than you realize.

Tomorrow’s rainfall risk shifts southward into the Southeast, mainly the Carolinas.

A slight risk (2/4) of heavy rainfall and flooding exists in the Carolinas for Friday. (NOAA WPC)

That risk will probably hold steady in that area for Saturday as well.

Tropics still mostly benign

Another day with no tropical threats on the map from the National Hurricane Center today. As all the thunderstorms in the Southeast begin to push offshore, there is a very, very slight risk that something may try to briefly spin up and head out to sea from there. But those odds look quite low.

Overall, the Basin looks about average for this time of year right now. Over the next couple weeks, I’m not convinced it’s going to get more favorable. Of course, given that climatology begins to ramp up in August, that should still mean we see something at some point in the next 2 to 3 weeks. That’s just a given. But in terms of getting a lot of activity, significant activity, etc., I’m not sure I see the background state of the Atlantic cooperating in a significant way right now.

If you want to look out far in time, we can grab the European model’s subseasonal outlook for tropical storms.

The odds of a tropical storm per the Euro weeklies yesterday is highest off the East Coast in mid-August. (ECMWF)

The odds of a tropical storm in mid-August (we’re looking at the week of August 11th here) aren’t exactly strong. Some European model data suggests perhaps something could emerge off the Eastern Seaboard, but the odds at this point remain below 30 percent, or close to normal for this time of year. Conditions may become a smidge more favorable by later August, but again, that should be expected in a normal hurricane season.