Matt Lanza

Setting up a Southern soaker this week

In brief: The setup for a heavy rainstorm continues to look ripe from Texas into parts of the Southeast this week. Rain is likely to cause areas of flash flooding between Texas and Mississippi or Alabama through Wednesday or Thursday. Tropical development remains unlikely, but even if it were to occur, the primary impacts this week will be due to rain.

A look at the Gulf from late this morning shows the disturbance we’ve been watching for a bit now over Mexico and just south of Texas.

A tropical disturbance over Mexico will become the focal point of a significant rainstorm over the Deep South. (WeatherFront)

While this thing is not organized, nor is it expected to become organized, it will continue to presumably be a source of moisture that, when combined with an approaching front, sets up a potent rainstorm over the Deep South this week.

When we look at precipitable water, or the amount of moisture in the atmosphere this week, we can see a surge of it across Texas and the Gulf Coast. While I am suspicious of the final few frames of the loop below, I think the point stands that there is going to be substantial amounts of moisture available. PWAT values will stand around 50 to 70 mm, or not far off the historical maximums for this time of year. In other words, the atmosphere is going to be loaded with moisture.

A significant surge of moisture this week will help amplify heavy rain from Texas into Louisiana and parts of Arkansas, Mississippi, Alabama, and Georgia.

So we have a disturbance and a cool front, both of which will act as triggers. We have ample moisture. Basically, we have the ingredients in place for a substantial rain event in the South. Now the question becomes: How much and where?

Well, that’s always the challenging part in these events. Let’s start with the big picture. Here’s how much average rainfall is expected over the next 5 days from the National Weather Service.

A stripe of torrential rain is likely from near Brownsville through Corpus Christi, Houston, Lake Charles, and into southern Mississippi. (Pivotal Weather)

So that basically a stripe of 3 to 7 inches of rain from northeast Mexico through southern Mississippi, including Brownsville, Corpus Christi, Houston, Beaumont, Lake Charles, and Jackson, MS.

We know that historically in setups like this, there often tend to be slower moving, or “training” bands of heavier rainfall that can pop up, dumping anywhere from 2 to 4 inches in an hour over a given location. In fact, if you look at the overnight high resolution ensemble from the Storm Prediction Center, the probabilities of 5 inches or more of rain in a 24 hour period is rather high from tonight through tomorrow night. The key here is not to focus on any one spot, but to accept that there is a strong signal of potentially very heavy rain in a short time over a broad area.

HREF model probability of 5″ or more in 24 hours tonight through Monday night.

Basically, we know that someone is probably going to come out of this with 10 inches of rainfall, but we do not and probably will not know where until the event really gets moving along tomorrow and Tuesday. At this point, folks from Texas through Mississippi and Alabama should prepare for potentially disruptive travel heading into this week at times. Many areas are under a slight risk (2/4) for excessive rainfall this week, and that may get upgraded to a moderate risk (3/4) at some point. Flood Watches are now posted from south of San Antonio through the Houston area. Additional expansion of these watch areas is likely in the next day or so.

Flood watches are posted for the Corpus Christi, Laredo, and Houston areas in Texas as of Sunday midday. (Pivotal Weather)

Another wrinkle in all this is what happens as the disturbance exits mid to late week. A few European ensemble members (and notably the operational Euro model) try to wind this thing up on exit. It doesn’t look purely tropical but rather almost hybrid-like. A number of the European AI ensembles also show this.

The potential exists for a more organized low pressure area with heavy rain on Wednesday or Thursday as this pattern begins to clear out of the system. (Weathernerds.org)

I am doubtful of this being the case but given the ample support on the AI ensemble, it’s a potential risk. This would be unlikely to develop into a tropical entity, but a situation with heavy rain, thunderstorms, and 20 to 30 mph winds can’t be entirely ruled out between Texas and Mississippi on Wednesday or Thursday. Additional flash flooding risk is possible until the pattern begins to break down later this week.

There are no other tropical concerns of note in the Atlantic.

More tomorrow!

Gulf development unlikely, but soaking rain coming for the Gulf Coast

In brief: While formal tropical development seems unlikely from a Gulf disturbance, the combination of surging tropical moisture and elevated moisture pooling ahead of a cold front may setup a pretty significant heavy rain and flash flooding sitWuation from Texas through Alabama later Sunday through Wednesday.

The National Hurricane Center designated an area to watch yesterday morning in the Bay of Campeche. We’ve been talking about this area on again and off again for a little while now, and it’s now firmly in view.

The Gulf disturbance has maybe a 10 percent chance to organize into a depression or so. (NOAA NHC)

On satellite, there’s definitely a disturbance evident, but what is missing is any sort of surface reflection of this. We’re just dealing with a little too much turbulence in the western Gulf right now to think this has a realistic chance to organize. Wind shear quickly builds to 20 to 30 knots north of the system, so it’ll be entering increasingly hostile territory.

Gulf disturbance has a good deal of moisture but lacks much organization at all. (WeatherFront)

So, we don’t expect much of anything formal from this.

That said, this is going to setup a somewhat interesting situation in the Southern U.S. beginning later Sunday and lingering through Tuesday. As tropical moisture from this disturbance surges northward, it’s likely to interact with a somewhat unusually far south cool front for mid-June. The combination of a slowing/stalling front, already high moisture levels, and a surge of tropical moisture straight out of the Gulf and Caribbean is going to fuel a somewhat potent rainfall setup for a couple days.

Surging moisture out of the Gulf will collide with moisture pooling around a cold front in Texas, Louisiana, Mississippi, and Alabama early next week leading to heavy rainfall. (Pivotal Weather)

It’s still a bit difficult to pin down exactly how much rain is expected and where is likeliest to see the highest totals. However, it seems that we’ll see heavier rain focus on Texas, including the Houston area Sunday night and Monday, spreading east into Louisiana Monday and Tuesday, and then east of there toward southeastern Louisiana, southern Mississippi, Alabama, and parts of the Florida Panhandle by Tuesday and Wednesday.

An average of 1-4 inches of rain is likely from Southeast Texas into the Deep South, but there will likely be higher amounts, perhaps up to 4 to 8 inches or so in some areas. (WeatherFront)

We’re already seeing slight risks (level 2/4) issued for flash flooding risk Sunday through Tuesday. It is possible we see that upgraded to moderate risk (3/4) at some point. I would watch the Houston area and southern Mississippi closest right now for more disruptive flooding risks.

That should clear out by mid to late next week, and then hopefully there will be some time to dry out. These areas will need it. More to come probably on Sunday.

Pacific tropical moisture will assist heavy rain chances this weekend across the Southern U.S.

In brief: As high moisture and additional moisture from the Gulf and Eastern Pacific converge on the Southern U.S. this weekend, heavy rain chances will nudge up. We also check in on Pacific water temperatures and what they tell us about the next few weeks of hurricane season.

A return to more unsettled, wet weather is coming this weekend for the South. While no organized tropical system is expected to develop in the Gulf, a boost in atmospheric moisture across Texas, parts of the Deep South, and Southern Plains will come courtesy of Tropical Storm Cristina’s remnants from the Pacific.

(NOAA NHC)

While Cristina is moving slowly toward the coasts of El Salvador and Guatemala, it will begin to pick up a little speed and its remnant moisture will end up in the Bay of Campeche by Friday with additional moisture following behind it.

Moisture (in darker green) will move across Central America and into the Bay of Campeche and eventually southern Plains this weekend. (Cyclonicwx.com)

As all this moisture funnels north and combines with already elevated moisture levels in the Southern Plains and Deep South, we are likely to see areas of heavy rainfall emerge beginning Saturday and continuing into Monday or so. Modeling does not entirely agree on where the heaviest rain will occur with this setup, but it does appear that areas near the Gulf Coast from Texas into Mississippi (as AI modeling thinks), as well as eastern Oklahoma through Arkansas and Missouri will probably be at the highest risk of seeing 2 to 4 inches, with locally higher amounts.

NBM model rainfall forecast over the next week, with highest amounts in the Mississippi Valley and Plains. (WeatherFront)

In fact, parts of Oklahoma and Arkansas are already in a slight risk (level 2/4) for excessive rainfall on Saturday, slinking south on Sunday.

I think it’s notable to point out just how warm the water in the Pacific is, and this is outside the main El Niño regions we watch. Just in general, the Eastern Pacific is extremely warm right now, and that’s likely aiding in some of the locally heavier rains we’ve seen across the Southern U.S. over the last several weeks.

The East Pacific is absolutely red hot right now, which likely will aid in both tropical activity there, as well as increased moisture availability downstream into parts of the U.S. at times. (Cyclonicwx.com)

I would expect to see continued tropical activity on the Pacific side of Central America in the days and weeks ahead as well, even if the stronger background support that we’ve seen lately fades a bit. But with a “beginning to rage” El Niño in place, history suggests that’s one place the action will be pretty constant this season.

For folks on the Atlantic side of things, it continues to look fairly uneventful for a bit.

A lot of unsettled weather expected in the Gulf and South but no real organized development expected heading into next week

In brief: While Gulf development continues to be unlikely, we will probably see unsettled, wet weather try to make another run at the Gulf Coast, Southeast, and Texas next week. The Pacific remains congested with a lot of lower-end activity, as El Niño continues ramping up. Plus, we address reader questions on recently announced ocean research cuts.

Gulf update

The good news is that the odds of any Gulf development continue to remain pleasantly low over the next 7 to 10 days. A little bit of “noise” continues to show up in modeling by this coming weekend and early next week. Even the slightly busier ensemble model from the European ensemble is showing a fair bit of shear in the Gulf next week as well, so the chance of anything significant growing out of any storminess is extremely low.

Around 20 kts. of northerly shear should be present in the Gulf next week. (Tropical Tidbits)

Still, we’ll watch. I think more interestingly will be the precipitation we see emerge in this pattern, with another soaking possible from Texas into the Southeast either beginning this weekend or next week. Through this past Saturday, many parts of the Gulf Coast and Texas had seen 150 to 300 percent of normal rainfall over the previous month.

Rainfall from early May through early June has been rather prolific across the Deep South and Gulf Coast. (High Plains Regional Climate Center)

Another surge of moisture may lead to additional flooding concerns in these areas, so we’ll see how that evolves.

Eastern Pacific

Meanwhile, the Eastern Pacific remains busy, with Amanda dissipating out at sea, and Tropical Storm Boris near the Mexican coast.

Tropical Storm Boris will be out of the picture very quickly. (NOAA NHC)

I have to be honest: With a name like Boris, I expected more. Anyway, the second Pacific storm of the season will move ashore tonight as a tropical storm. Behind that is another disturbance passing off the coast of Nicaragua that will continue up the coast and eventually probably move inland. There is a chance that this one also becomes a tropical storm.

Boris and its disturbance friend off the coast of Mexico and Central America. (Weathernerds.org)

There’s just a lot of congestion along the Central America coast on the Pacific side, again, usually a calling card of an El Niño event.

Miscellany

We’ve been asked by a number of readers about a story making the rounds that first appeared in the New York Times about the Trump administration cutting and removing a deep ocean observation system around the globe. This project began 10 years ago and included over $350 million in instruments measuring a number of variables and data in the oceans to help us better understand what is happening on our planet. There’s no real good reason for these instruments to be removed. Or at least no one has shared any. The quote from the National Science Foundation’s spokesperson in the article reads, “aligns with N.S.F.’s wider strategy to have a nimbler approach to prioritizing support for evolving scientific priorities and emerging technologies as well as a deliberate approach to smart life cycle management within its portfolio of research infrastructure.”

In other words, they’re removing it because they don’t want to maintain it, which is kind of part of how science research works. Presumably the upkeep of this project (O&M cost in corporate parlance) as a legacy project had been accounted for in budgets, which opens the door up to any other number of reasons for removing it (like, perhaps because it also informs climate change research) that one can think of. You don’t just invest $350 million dollars in something that works and dismantle it to save a few bucks on maintenance. Or at least most business minded folks would not find that to be particularly efficient.

Anyway, the point is that this reduction is quite unnecessary. Yes, there are climate change research implications here. But there are also broader oceanographic, marine science, and yes, meteorological implications. Some stations help measure currents and provide added value to our broader understanding of coastal flooding, which is increasing all over the country. This continues a pattern that began last year by this administration and continues which is essentially death by a thousand paper cuts to the weather and climate fields (and science in general), implications be damned. We’re not being partisan here, we’re just being truthful.