Matt Lanza

October 19, 2023 Outlook: Tammy toys with the Caribbean islands, while Norma rapidly intensified overnight in the Pacific

One-sentence summary

Tropical Storm Tammy and Hurricane Norma strengthened overnight, but the hope is that most of their impacts will be glancing for the Caribbean Islands (Tammy) and Baja or Sinaloa (Norma) heading into this weekend.

Atlantic Tropical Storm Tammy: Strengthening and will be a close call in the Lesser Antilles

We will start today in the Atlantic, where Invest 94L leveled up to Tropical Storm Tammy yesterday. Tammy now has 60 mph winds after strengthening overnight.

Tammy is strengthening this morning, but its center remains fairly displaced to the north and west of most of the thunderstorm activity. (Weathernerds.org)

I’m not sure I’d classify Tammy as well-organized this morning, but it’s something. Whatever the case, given the higher starting point now, it won’t take much for Tammy to become a hurricane from here. Much of the northern Lesser Antilles are under tropical storm watches this morning. This includes Barbados, Dominica, Martinique, Guadeloupe, Antigua, Barbuda, Montserrat, St. Kitts, and Nevis. With the strengthening this morning, I would anticipate we see watches expanding and some hurricane watches or warnings hoisted later today.

In terms of track and impacts, Tammy will start to turn later today, first west-northwest and then northwest. Given how far south it’s starting from and how far west it already is, it will likely run into the islands before turning northward enough, meaning direct impacts are likely beginning tomorrow. Tropical storm force winds will probably arrive tomorrow morning sometime in Barbados, spreading north and west through the day. Tropical storm force winds would most likely arrive in Puerto Rico and the Virgin Islands on Saturday.

Tropical Storm Tammy is expected to scrape the northern half of the Lesser Antilles. It should track east of the Virgin Islands and Puerto Rico, but impacts are still a possibility there. (NOAA NHC)

A stronger Tammy would be more apt to turn northward a bit faster, so that may be good news for Puerto Rico, which could (should?) end up being spared any kind of meaningful wind impacts from Tammy. Still, it’s close enough, and it’s not as if there will be no impacts. The weather in Puerto Rico looks active the next couple days regardless, with excessive heat in San Juan and the north coast today and some locally strong thunderstorms and heavy downpours today and tomorrow in interior Puerto Rico. Folks should continue monitoring Tammy at least, but the hope is it will be a close miss to the east.

Heavy rain will be possible in the Leeward and northern Windward Islands with anywhere from 2 to 6 inches of rain possible. The heaviest rain will miss to the east as long as the track stays close to forecast. If Tammy does somehow track closer, as much as 8 to 10 inches of rain would be possible for some of the islands.

Beyond the islands, Tammy will continue turning north and head out to sea, looking as if it will pass well south and east of Bermuda at this time.

Pacific Hurricane Norma: Rapidly intensifying but should weaken a good bit on approach to land

Shifting west now, and we’ve had some changes overnight in Norma. As has been the case a couple times this season, rapid intensification outpaced the forecast, as Norma is now a category 3 storm with maximum winds of 120 mph.

Hurricane Norma exploded into a major hurricane overnight with winds now of 120 mph and much more classic looking structure. (Tropical Tidbits)

The good news for land is that Norma is expected to weaken as it approaches the coast of Mexico. So while we have a major hurricane now, should it track toward Baja or Cabo, it will likely not be a major hurricane there. It may still be a hurricane however or close to hurricane intensity as it approaches Baja on Saturday and Sunday. Thus, a hurricane watch was issued for Baja.

Norma is expected to slow down and weaken considerably as it approaches Baja. While it may still be a hurricane as it approaches, it will become a moisture-laden tropical storm with heavy rain possible for the southeast tip of Baja and perhaps parts of Mexico. (Tomer Burg)

Ultimately, Norma’s biggest impact may be rain. Moisture from Norma will spread northward across Mexico and probably into Texas.

Click to enlarge a map of forecast rain through next week from Mexico into Texas and the Southern Plains. (NOAA WPC/Google Earth)

Rain totals through midweek next week may approach 1 to 3 inches in much of interior Texas north into Oklahoma and Kansas. Additional rain may follow late next week with a front. So overall, while Norma is rather potent this morning, the hope is that it will bring mostly beneficial rainfall. That said, interests in Mexico, particularly Sinaloa and Baja should continue to watch Norma’s progress closely.

October 17, 2023 Outlook: Invest 94L still may develop, while Invest 90E in the Pacific will likely develop and eventually track toward Mexico

One-sentence summary

Invest 94L is slightly better organized this morning in the Atlantic but still has a long way to go to develop, while Invest 90E is likely to develop today or tomorrow and will eventually be a concern for Mexico.

Tropics: Invest 94L

Thunderstorm activity improved around Invest 94L yesterday evening, and this morning, while it’s clearly heavily sheared, it actually has a bit of a nascent organizational “shape” to it.

Invest 94L, while heavily sheared this morning, is at least maintaining robust thunderstorm activity, a necessary precursor to development. (Weathernerds.org)

There’s clearly still a long way to go here, but 94L is at least taking baby steps toward organization today. Whether or not it maintains those baby steps or throttles back in reverse remains to be seen.

The track forecast has not changed much for 94L’s future. In general, if it can get its act together over the next day or two, there’s a good chance it will start to shift northwest faster. If it remains a discombobulated mess, it will probably track toward the islands with some impacts, albeit most likely on the lower-end of the intensity spectrum.

Invest 94L should track west or west-northwest toward the islands, unless it develops quickly, in which case it would follow the northern edge of that track density plot. (Tomer Burg)

This remains a system to keep an eye on in the Caribbean islands, but probably nothing to worry a ton over still at this point. We’ll continue to watch it closely through the week.

Pacific Invest 90E

Meanwhile, in the other ocean, Invest 90E is on the cusp of developing into a tropical depression or storm.

Invest 90E (center) is likely to become a depression or storm in the next 24 hours or so. (Weathernerds.org)

Invest 90E is a little more intriguing from a potential impact standpoint, as this is expected to organize rather considerably and track toward Mexico. This bears watching from southern Baja to northern Jalisco and Puerto Vallarta in Mexico.

Next significant U.S. weather event? Not for a bit

With a quiet stretch ongoing across the country much of this week, the question is: When will we experience our next significant weather event? Well, we may be looking at another 1 to 3 inches of rain this weekend in parts of the Northeast, an area that has seen below normal rain in portions of New Hampshire and Vermont and almost 200 percent of normal rain in portions of Southern New England and near New York City.

Rainfall since mid-August has been dramatically above normal in Southern New England and in the NYC metro, while it has varied in northern New England and across Upstate New York. Another 1 to 3 inches is expected this weekend. (High Plains Regional Climate Center)

So how wet your soils are depends a bit on where you live in the Northeast or parts of the Mid-Atlantic. I would suspect 1 to 3 inches of rain wouldn’t cause any serious flooding issues, but it’s something to watch.

Record warmth

California is set to experience a couple days of near record and record warmth for mid to late week. Thursday’s forecast highs show records in a few spots in interior California from east of San Diego all the way north to Medford, Oregon.

Any location boxed in on the map above is expected to see a record high temperature on Thursday. (Weather Bell)

Weak to moderate offshore winds will also help keep temps up overnight, allowing many locations to set or tie record warm minimum temperature levels on Wednesday night and Thursday night. Some of that record warmth will expand into the Desert Southwest and Texas heading toward the weekend.

But truthfully, aside from these items, it’s a quiet stretch for autumn here in the States. I suspect we will want to watch the Pacific tropical system and a potential cold front later next week for some more significant weather chances, but that’s a long way off. For now, enjoy the quiet.

October 16, 2023 Outlook: Invest 94L has a muddy future in the Atlantic, while the Pacific heats up a little

One-sentence summary

Invest 94L in the Atlantic is struggling as it continues to plod west toward the Caribbean, while Invest 90E in the Pacific has some potential to develop and impact Mexico in the next 7 to 10 days.

Tropical Outlook: Invest 94L’s on-again/off-again potential

It’s been interesting to watch Invest 94L over the last several days. We’ve seen cycles of model runs that are quite bullish on development, followed up by cycles of model runs that are not. We are currently in the latter, where model support has waned for Invest 94L’s development. That’s not say it’s impossible (the NHC still gives it 70% odds over the next week), but it is not looking nearly as robust as it did late last week.

Thunderstorm activity around Invest 94L is not exactly organized this morning. (Weathernerds.org)

On satellite this morning, you can see the convection (thunderstorm activity) this morning around 94L struggling a bit. There is no organization to this. It looked far better on Saturday, then collapsed yesterday. And here we are. Over the next 2 to 3 days it should plod west and will probably wax and wane in organization.

The total density track plot for 94L as of yesterday showed a broad track toward the Lesser Antilles, but low confidence in how much development we’d see on that path. (Tomer Burg)

Folks in the islands probably want to continue to monitor the progress of 94L, as it almost certainly tracks in that direction. Overall, 94L certainly looks less menacing than last week. But it still has a chance at becoming a tropical storm or better. Beyond the islands, 94L would probably turn north and eventually out to sea, assuming it organizes. We’ll keep an eye on it this week.

Elsewhere, Sean finally met its demise late last night. Sean tied for the 6th least amount of generated ACE this season in the Atlantic meaning it was not much of a storm. There are no current signs of any further activity behind Sean’s remnants and Invest 94L at this time.

Pacific outlook

The most interesting of the potential tropical systems in the Atlantic or Pacific is probably in the Pacific. Invest 90E seems likely to develop over the next couple days as it meanders over the open Pacific. Steering currents do suggest that this one will shift back north and eventually east toward the coast of Mexico at some point, so this bears close watching there.

From the Euro ensemble overnight, you can see a pretty basic calculus for Invest 90E. If it develops with some potency, it will likely turn north or northeast back toward Mexico. If it struggles, it may meander south of Baja offshore. (Weathernerds.org)

Much like in the Atlantic, a weaker storm would probably plod farther out to sea, whereas one that organizes more quickly would be apt to turn north and eventually northeast. Right now, given that 90E has pretty robust thunderstorm activity, the money may be on the latter outcome. We’ll see what we’ve got here over the next few days.

U.S. Weather update: Quiet but warming

We will have a pretty quiet week across the country this week, with no real serious weather to speak of. We will likely have some warm temperatures building out of the West, with some record highs and a number of record warm minimum temperatures later in the week.

Temperatures will begin the week cool in the East, but building warmth in the Western U.S. is likely to spread eastward as the week goes on. (Weather Bell)

Otherwise, it looks pretty quiet for most of this week across the country!

October 13, 2023 Outlook: A solar eclipse viewing forecast, plus watching potential Atlantic trouble next week

One-sentence summary

Decent viewing is expected for this weekend’s solar eclipse, with a few exceptions, while we have a few days to check on Invest 94L before it develops and potentially becomes a troublemaker in the Atlantic.

Tropics: Invest 94L emerges as a potential troublesome late season pest in the Atlantic

Tropical Storm Sean regrouped yesterday, but it is expected to gradually fade away as it turns northwest over the next few days.

Behind Sean, however, lurks our next system. I was hoping we might have a couple days to chill out before we started really following this one, but here we are. Invest 94L is nothing to look at right now, and it only has a very low chance to develop into anything over the weekend. But as we go into next week, the odds are beginning to increase that something will come of this.

Over the next 7 to 10 days, Invest 94L is expected to trek west or just north of due west while only slowly developing. (Tomer Burg)

While we’re a long way from having to actually worry about this, there’s enough potential there to say this is going to be worth watching. As Sean exits, the central Atlantic is going to fill up with a pretty beefy ridge of high pressure. Winds turn clockwise around high pressure, which means, 94L will be generally directed due west with minimal latitude gain over the next several days. Wind shear may or may not begin to lighten up a bit on its track as well, and that will help determine what upside there is to this system.

High pressure over the central Atlantic will steer 94L due west or just north of due west for much of next week. (Tropical Tidbits)

What is troublesome is that the odd lack of latitude gain and the oddly far south for October placement makes this a candidate to potentially run into the Caribbean islands. And if it can find a hospitable environment to strengthen in before that point, well we may actually have a storm to watch in the Caribbean in 8 to 10 days or so. For now, any talk of 94L’s end game is speculative at best, but this will merit watching in the days ahead.

Eclipse Outlook

Alright, tomorrow around midday central time is the big event! Our annular eclipse will occur, with totality from Oregon into northern Nevada, southern Utah, New Mexico, and west-central Texas. Will the skies cooperate?

Much of Texas will have good viewing, but cloud cover looks a little more prevalent in portions of the Panhandle and Rio Grande Valley. (Weather Bell)

Per the NWS outlook, Texas looks mostly good. As you get into the Rio Grande Valley, there will be cloud cover, particularly between McAllen and Del Rio. There will likely be at least some cloud cover in Brownsville, San Antonio, and Corpus Christi. The Panhandle will also see clouds, as should southeastern New Mexico, though hopefully not a total overcast.

Some patchy cloud cover may spoil viewing a little in northern Utah, but southern Utah looks mostly good, as does northwest New Mexico. Anyone hoping to view in Monument Valley, the Grand Canyon, or southern Utah parks should be good. (Weather Bell)

Utah will have at least some cloud cover in most spots, but it does not seem like enough to obscure the eclipse, especially near the path of total annularity. Coastal Oregon looks clouded in, with gradual improvement as you head east across the state and into Nevada, which should just have patchy clouds here or there.

Coastal Oregon will probably have the sun obscured by clouds, and conditions may struggle a bit farther inland but conditions improve in Nevada. (Weather Bell)

Overall, the only two places that I think will have real problems are coastal Oregon and portions of the Rio Grande Valley. Hopefully you’re able to see it where you are if in the path, and please remember to use eye protection!

Elsewhere, we should hopefully see the beginnings of calmer weather this weekend nationally after some heavy rain of 1 to 3 inches today for Chicago, Milwaukee, Madison, and Minneapolis. An inch or two will fall tomorrow in the Mid-Atlantic as well. More for you Monday!