October 2, 2023 Outlook: Philippe stands alone, while rain and cooler temperatures are coming to the Rockies and Plains this week

One-sentence summary

Philippe will brush the northern Antilles on its way out to sea this week, while the Atlantic temporarily calms down.

Tropical outlook: Philippe takes control, a brief break follows

Over the weekend, we watched the ballet between Rina and Philippe take place over the open Atlantic. As expected, Philippe won. These are not necessarily easy interactions to forecast, but truth be told, I think modeling did about as well as you could hope! Philippe basically sagged south as expected, while Rina overshot it to the north, and here we are this morning with the remnants of Rina to the north and Philippe to the south, readying to turn north and eventually out to sea.

An impressive burst of thunderstorms on the southeast side of Philippe’s center will impact the central and northern Lesser Antilles today, with pockets of tropical storm conditions possible. (Weathernerds.org)

That being said, before Philippe exits, it may brush some of the Lesser Antilles with some tropical storm conditions. Hence, Tropical Storm Watches are posted for Antigua and Barbuda, although judging by the satellite imagery above pockets of tropical storm conditions are possible for Martinique north through Anguilla. Philippe should creep northwest and then turn north over the next few days. It will begin to accelerate northward back into the open Atlantic later this week. There is a chance it will become our next hurricane as it does so. The good news is that it should not impact land beyond these modest impacts in the islands.

What to watch next: Caribbean & Gulf

We should enter into a period of quiet over the next 5 to 7 days in terms of new development. There’s not much out there on modeling, and the National Hurricane Center has not highlighted any areas to watch at this point either. So, we’ll assume that for this week, it’s Philippe and that’s all.

Now, next week? That’s another story. We expect the Pacific to pick up this week, with a potential developing storm off Mexico. Whether that becomes an issue for Baja next week is another story, as there is a bit of uncertainty around Invest 98E.

That said, the center of action is going to shift to the Eastern Pacific over the next week, and then possibly eventually into the Atlantic basin again, this time focused on the Gulf and Caribbean. Climatologically, this is where you’d be looking in October also. While there is no specific feature I can point to yet, there are growing amounts of noise showing up late in the northwest Caribbean and eastern Gulf. Any system that *can* develop there would probably track north or north-northeast into the southwest Atlantic or eastern half of the Gulf. But we are a long way off from being able to say more than that. This is something we’ll watch this week.

The individual members of the GFS ensemble tell a complicated, uncertain story around Invest 98E in the Pacific, which has a wide range of potential options heading into the weekend and next week. (Tomer Burg)

Additionally, it does make sense to keep an eye on Invest 98E in the Pacific, which does have at least some chance of funneling moisture up into Texas next week. In addition to potential impacts in Baja, there’s a slight chance it could deliver moisture into more of Mexico or the U.S. But too many questions remain to get too serious about this one.

U.S. weather update: Texas rain and a sweeping cold front

As we noted last week, as hurricane season calms down, we’ll be transitioning to cover some other noteworthy weather stories. This week, the focus is on Texas and temperatures, as some big weather pattern changes at least temporarily establish themselves.

Midwest warmth & Texas rain

A rather classic autumn weather pattern will establish itself this week, as a storm system establishes in the northern Rockies and ejects out across the northern Plains into Canada. This storm will drag a cold front out of the Rockies, onto the Plains, and then off to the east late this week and weekend. Ahead of the front: Very warm and very humid air builds up. In fact, a number of locations are likely to set record highs today and perhaps tomorrow too, including Des Moines, Fargo, Minneapolis, and Green Bay. Heat warnings are even posted in southwest Ontario in Canada for this weather.

Record high temperatures are expected in boxed locations today between Nebraska and South Dakota into Michigan. (Weather Bell)

As the front kicks off, showers and storms will begin to pop ahead of it with strong to severe storms possible in eastern New Mexico and west Texas today, particularly just west of Amarillo, Lubbock, and Midland.

Isolated severe weather with hail and damaging winds will be possible today in eastern New Mexico and portions of extreme western Texas. (NWS Albuquerque)

Tornadoes are not expected, but strong winds and hail are possible. Additionally, heavy rainfall will accompany these storms, with a slight (level 2/4) risk for excessive rainfall in eastern New Mexico and west Texas today.

Areas of flash flooding are possible. That threat of heavy rain will expand east into Central Texas as the week progresses, especially on Wednesday and Thursday. The front will finally bring some much needed relief from almost non-stop excessively hot weather in Texas since July. And the rain will be very, very welcome, as much of Texas remains in serious drought.

Rainfall for the next seven days across the southern Plains will be very beneficial for Hill Country, the Rio Grande Valley, and extending up into Oklahoma. (Pivotal Weather)

Rain totals in Texas this week will be on the order of 1 to 3 inches, with higher amounts possible, especially in the Coastal Bend and around Corpus Christi, along the border with Mexico back toward Del Rio, and perhaps just east of Dallas.

Lower Mississippi still struggles as saltwater continues creeping toward New Orleans

The good news is that a fair bit of rain will fall in the Red River Basin and (to a lesser extent) the Missouri Basin this week, which will eventually end up in the Lower Mississippi. However, this is nowhere near enough. The lack of much rain in the Ohio River Valley is not helping matters either. We discussed this more in depth last week. We’ll keep monitoring things.

While rainfall in the Red River Valley looks decent, the needed rainfall to help feed the Mississippi River will be severely lacking in the Ohio Valley. (Pivotal Weather)

Some snows in the Interior West

It’s still a bit early for any real severely impactful winter weather, but as is often the case, we are beginning to see snow in the Rockies at times. The winners this week will probably be the western Uintas in Utah (one of the author’s favorite places he’s ever visited), where 4 to 8 inches of snow is expected today and a winter weather advisory is posted. Several ranges in Wyoming will also see a few inches of snow.

Snow fall of several inches is likely in the Uintas in Utah and portions of western Wyoming over the next day or so. (Pivotal Weather)

A number of places in the interior West and perhaps some in the northern Plains will also see their first frosts and freezes later this week as cooler air comes roaring in. After a long, long hot summer, it’s nice to be able to talk about cool weather again.

September 29, 2023 Outlook: Atlantic ballet and non-tropical flooding risk in NYC metro

In case you missed it yesterday, we had our first real non-tropical post in which we discussed the ongoing salt water intrusion issues in Louisiana related to low-flow of the Mississippi River. While today’s post functions as an outlook, we will also discuss the developing flooding situation for New York City.

One-sentence summary

Philippe and Rina will dance, with Philippe eventually taking over as the dominant system, lifting into the Atlantic, while today we also check in on flooding in New York City.

Tropical Outlook: Philippe & Rina dance, while the rest of the basin settles down

Philippe & Rina

These two. Tropical Storms Philippe and Rina are now unable to be dissociated from one another, as we are seeing the Fujiwhara effect play out in real time. The two storms will interact and probably repel one another, with Rina likely taking a backseat to Philippe.

Philippe and Rina will track near each other with Philippe most likely to become the dominant system in the Atlantic before turning north. (Tomer Burg)

Basically, Philippe will stall, Rina will sling shot over the north side of Philippe, turn north and dissipate, and then Philippe will begin moving out to sea again. There has been a good deal of model uncertainty, particularly with respect to Philippe’s future intensity. And that is normal for a Fujiwhara interaction. When two storms engage like this and are this close together, inherent uncertainty increases, and that leads to a bit of forecast uncertainty. It’s becoming more likely however that Philippe becomes a stronger storm that pulls north, and I wouldn’t be to see the National Hurricane Center bump up their forecast intensity as it moves north into the open Atlantic.

Philippe and Rina will dance around each other over the next 4 or 5 days before Rina likely dissipates and Philippe becomes a larger storm over the open Atlantic. (Weathernerds.org)

As we’ve noted through the week however, even in the unlikely event that one of these systems ends up in the islands, it will be on the lower end of intensity and unlikely to create too much trouble. But confidence seems to be building in a no-impacts scenario. Both of these systems should be on their way out by later next week.

What else is out there?

Throughout the week we’ve also told you a bit about potential upper low or weak tropical development off the Southeast coast next week. Support for that has faded as a pretty decisive autumn cold front sweeps across the Southern and Eastern U.S. later next week. Finally! The hope would be that this leads to quieter tropics for a time. The season is by no means over (though for the northwest Gulf and Cabo Verde region it probably is), not with record warm water temperatures out there, but the pace should finally slow a bit. We’ll have more on this next week.

Metro New York City flooding underway

A few flash flood warnings have already been posted for the New York City area this morning as heavy rains stream into the area. Most of the City outside of the Bronx has seen some flooding with 1 to 3 inches of rain so far and the potential for a good deal more to come.

Heavy rain will continue to push into New York City and Long Island today, setting up a fairly substantial flash flooding event in that area. Travel to NYC area airports will likely be impacted through afternoon (RadarScope)

This should continue the flash flooding threat across northeastern New Jersey, New York City, Long Island, and southwest Connecticut. It’s likely that the heaviest rain will fall somewhere between Islip on Long Island and Newark, NJ. The worst conditions will be this morning into early afternoon with gradual improvement this evening.

The Weather Prediction Center arm of the NWS has set a moderate risk (level 3 of 4) for excessive rainfall and flooding in the Tri-State area around NYC. (Pivotal Weather)

Some places could see in excess of 3 or 4 inches more rainfall which will likely lead to considerable street and some local creek or river flooding. Be safe in the New York City area today, and if you’re traveling that direction, be prepared for some delays and hassle.

To solve Louisiana’s Mississippi River salt water crisis a significant weather pattern change is needed. Is any in sight?

At The Eyewall, we’ve focused on hurricanes and tropical storms since our launch in June. Some of you have asked what we’ll do during the offseason, and the answer is we will probably pull back our posts to every few days unless there’s a major weather event, and we will focus on extreme weather impacts in North America. We don’t want to offer clickbait or drama, but a forecast, an explanation, and context. I’ve decided to roll out something of that nature today with a focus on the Mississippi River salt water intrusion crisis in Louisiana.

One-sentence summary

The situation with salt water creeping up the Mississippi River in Louisiana is a complex one but one that has a basic solution (more rainfall) that does not look likely to be in the cards over the next 2 to 3 weeks in any meaningful capacity.

What is happening?

If you’ve been following the news lately, you may have heard about salt water creeping upriver in the Mississippi River in Louisiana. In the most simple terms, as dry weather has led to low river flows in much of the Mississippi Valley, denser salt water has been able to creep north at the bottom of the river. This isn’t unprecedented, but it isn’t common either. This happened to a much lesser extent last year and more notably back in 1988, when the salt water barrier shifted over 100 miles up the river west of New Orleans. This led to a couple days of salt water intrusion into New Orleans’ water supply which ended quickly.

WWNO, the NPR affiliate in New Orleans has a great rundown of what’s happening.

Tulane’s School of Public Health & Tropical Medicine also published a “5 things to know” that is helpful.

Virtually the entire Mississippi Valley is in drought right now, with a good chunk of the Missouri and Ohio River Valleys that feed the Lower Mississippi also in drought or abnormal dryness. The hot, dry summer in Louisiana in particular has exacerbated the dryness and drought there, with the entire southern two-thirds of the state in either exceptional or extreme drought.

Louisiana is in pretty terrible drought right now, but the situation upstream on the Mississippi is only marginally better, with widespread dry or drought conditions into Minnesota and along the Missouri and Ohio Rivers as well. (US Drought Monitor)

The last 60 days have seen 5 to 50 percent of normal rainfall along the Mississippi south of Memphis. The Ohio Valley and Missouri Valley have both seen 50 to 75 percent of normal rain. All this combined with the extreme drought in Louisiana has led to a confluence of problems and an expanding salt water wedge.

Over the last two months, rainfall has been 25 percent of normal or less in much of southwest Mississippi and Louisiana, and only marginally better than that in most areas along the Mississippi, Ohio, and Missouri Rivers. (NOAA)

What is the rainfall outlook?

To solve this problem, the main thing you need is just simply rain. It needs to rain in the Ohio, Missouri, and Mississippi Valleys sooner than later. Is there anything in sight over the next two weeks? Not really. The Lower Mississippi Valley should see minimal relief. The Ohio Valley looks quite dry. The Missouri Valley and Upper Mississippi are more mixed, but we’re just not seeing signs of any appreciable rainfall over the next two weeks.

Both the European model (shown here) and the GFS model are advertising below average precipitation over the next two weeks over virtually the entire Mississippi River drainage basin. (Weather Bell)

This is why you are seeing so much news about preparations for this in New Orleans and other Louisiana communities. Without meaningful rain over the next two weeks, you will continue to see the salt water migrate north. Current weather forecasts push us out to about mid-October and current projections for the wedge have it getting to New Orleans in later October. Even if 10 inches of rain fell over Memphis on October 15th, it would take some time for that water to flow downstream and get to New Orleans and southeast Louisiana. And isolated rain is not the answer. This problem requires a lot of upstream rain over a broad area. So it seems pretty clear that this problem is going to worsen.

So when can we expect a change? Well, when we look at the Climate Prediction Center’s outlook for weeks 3 and 4 (and granted, this is from last Friday), we can see signs of life in Texas or the Southern Plains, but probably nothing that would help “solve” the problems in Louisiana.

The situation within the Mississippi Basin does not look to improve a whole heck of a lot in mid October either. (NOAA)

The CPC outlook for October is positive with a lean toward above normal rainfall in the mid-Mississippi Valley. I’m not sure if changes over the last week since this map’s release have necessarily lowered chances of this outcome, but I don’t believe they’ve helped much.

The bottom line: The situation with salt water in the Mississippi River is going to worsen in the coming weeks, and there is not necessarily any strong signal for changes in the rain patterns over the key areas required to alleviate the problem. We need to see a change in the rainfall chances in either or all of the Ohio, Mississippi, and Missouri River Valleys before we can be confident that some help will be on the way. And at least into mid-October and possibly late October, that’s not likely to occur.

September 28, 2023 Outlook: Complex interactions between Philippe and 91L complicate the Atlantic forecast some

One-sentence summary

A complex interaction between Philippe and Invest 91L enhances a bit of uncertainty in the Atlantic next week as it relates to the islands, though most outcomes still favor minimal impacts in Puerto Rico, the Virgin Islands, and Lesser Antilles.

Happening Now: Philippe and 91L (future Rina?) and where will they go?

Looking at satellite this morning, the Atlantic is just jammed up with Tropical Storm Philippe and Invest 91L back to back. Personal space anyone?

Tropical Storm Philippe and Invest 91L are basically adjacent to each other, and at some point something will need to give in terms of which of these becomes the “big dog” of the Atlantic pack. (Weathernerds.org)

Anyway, this is actually important context to start today’s discussion with because the future and the future of any impacts will be somewhat contingent on which of these two becomes the dominant system in the Atlantic. On one side you have the GFS model, which has tended to overdo Philippe’s actual intensity, meaning that it has tended to slow it, park it as 91L interacts with it, and then take it north into the open ocean as a hurricane. The Euro essentially kills off Philippe and then sheds its remnants in the islands with some rain, while 91L tracks west as a weak system before turning north and strengthening.

Confidence in Philippe’s track is high until it gets just north of Anguilla, and then all bets are off. (Tomer Burg)

Interestingly, the setup here is one that seems to keep in play a Fujiwhara interaction between the two systems. What is that? Basically, the two systems would track close enough to one another to impact each other’s track. In this case Philippe would likely slow, stall, or get pushed to the south since it’s ahead of 91L, and 91L would basically slingshot over the top of Philippe either west or northwest and out to sea. The GFS operational model shows this quite well.

Philippe (at right) may slow or stall while 91L “slingshots” off to the west or northwest. Once that interaction untangles, Philippe would be free to turn north. (Tropical Tidbits)

In most possible outcomes, impacts to the islands are not exactly serious, so let’s make that abundantly clear. The arithmetic here is that if 91L (or as the GFS says, Philippe) ever explodes in intensity, it will “feel” upper level steering and turn north out to sea. Is there a chance that the system stays weak, tracks into the islands, and then blows up? I suppose that’s possible, but if it gets to that point, the theory would be that dry air or land interaction limit a lot of upside. So for folks in Puerto Rico or the islands, it would be unlikely that this is a major noisemaker as it comes in. We’ll continue to watch this, but for now the thinking is that it will just be an annoyance out there more than anything. Presumably if one of them does develop into a hurricane and turns out to sea it would happen east of Bermuda. We’ll keep watch and let you know if anything changes.

The medium-range (days 6 to 10): Noise off the East Coast?

We’re starting to get some sort of idea as to what might come next. Models have been consistently showing some sort of upper low or storminess between the southeast Gulf and off the North Carolina coast next week, but they have been wildly different run to run on details. The forecast idea today seems to be honing in on an upper low developing off the Carolina coast before a piece of it drifts southward toward or off the coast of Florida. Another lower-end system could theoretically develop from this, though the odds are fairly low.

The upper level map from the European model for next Monday shows the upper low exiting off the East Coast, with just enough “spin” (or vorticity) left behind to linger off the coast, unlikely to develop but worth watching. (Tropical Tidbits)

This probably means minimal impacts right now beyond rough surf and rip currents. But this is probably at least worth keeping a side eye on.

Fantasyland (beyond day 10): Still no substance to any threats

We’ve been saying that it may be wise to keep an eye on the northwest Caribbean or eastern Gulf in the late period all week. We continue to be faced with a weather map that does not really show any specific threats; just some noise. So I have no reason to believe that something *will* happen beyond day 10, but I also know that the big picture in the atmosphere doesn’t completely shut the door on that potential. We’ll keep watch.