In brief: Invest 95L continues to look likely to develop later this week as it mostly stays offshore and away from land. Hurricane Priscilla in the Pacific may deliver some decent rain chances to the Desert later this weekend. Meanwhile, a coastal/potential tropical or subtropical storm off the Southeast is beginning to show up on models this weekend. We discuss the potential for more beach erosion and coastal issues.
Invest 95L
Our Atlantic tropical wave, Invest 95L, is sitting around a 70 percent chance of development this week.
(NOAA/NHC)
95L is actually looking a bit better on satellite this morning, though it still is not quite organized just yet. Models have actually gotten a little more lukewarm on development chances here. Most indicate something akin to a tropical storm as this comes west-northwest toward the islands. It will likely curve back to the north and northeast eventually and likely before it reaches the islands.
A static satellite image of Invest 95L this morning shows more thunderstorms but not quite enough organization just yet to make it to depression intensity. (Weathernerds.org)
Models vary drastically on intensity from the typical HWRF enthusiasm of a major hurricane to various other models keeping it a lower-end tropical storm. My guess is that if this can maintain thunderstorms and get its act together sooner than later, we’ll see something of a significant hurricane, particularly as it turns northward away from land. If we sort of wax and wane the next 36 hours, we’re probably looking at a slowly intensifying system as it passes the islands to the northeast.
Either way, this does not appear to be a serious land threat, though folks in the extreme northeast Caribbean (Virgin Islands through Barbuda) should keep tabs on this in case you get broad brushed by something later this week.
Southwest US rain risk
Moving to the Pacific, Hurricane Priscilla has gotten its act together off the coast of Colima and Jalisco in Mexico. Tropical Storm Watches are posted from Puerto Vallarta to south of Manzanillo as some fringe impacts from Priscilla are possible there. Priscilla will track northwest, paralleling the coast of Mexico and Baja but likely remaining offshore.
Priscilla’s track will likely keep it offshore of Mexico, tracking it to off Baja by Saturday. (Polarwx.com/Tomer Burg)
Priscilla should peak in intensity tomorrow, close to a major hurricane. As it tracks over cooler waters off Baja, it will begin to weaken. The question from there is how much moisture it will deliver into the Southwest. This process should begin over the weekend, peaking on Sunday through Tuesday. The current rainfall forecast stops on Monday morning, but you can see a pretty widespread bit of rain across the area is forecast.
Widespread rain, possibly some areas seeing more than an inch will be possible from Arizona into New Mexico, Colorado, and Utah in the Sunday to Tuesday timeframe. (Pivotal Weather)
This is still 5 to 7 days out, so a lot can change, as we saw most recently with Lorena, where it failed to really deliver. But it is worth watching for folks in the Southwest.
Southeast coastal storm?
Another area to watch will be off the Southeast coast in about 4 or 5 days. We have a bit of a complicated setup with a cold front dropping southeast off the coast, low pressure trying to develop near the Florida Keys, and a disturbance trying to form off the Southeast. How exactly this plays out will determine a.) if it’s tropical and b.) what sorts of impacts we may see. Right now, it looks like a possible “nor’easter” type storm off the Carolina coast by the weekend. You can see how the operational European model brings all this together around 10,000 feet up.
A disturbance developing near or off the Carolina coast is possible this weekend. Invest 95L is seen passing well offshore on the right side of the loop above. (Tropical Tidbits)
The meteorological side of things is pretty complex here. This appears to be a frontal low that perhaps acquires some tropical characteristics as it develops. This would classify it as sub-tropical. However, in reality, this would be a significant coastal storm, regardless of classification, particularly along the Mid-Atlantic and Carolina coasts that have been beaten up this summer by passing storms offshore. We’ve seen numerous houses get washed away in the Outer Banks as rough seas and erosion from storms like Erin and Imelda and Humberto churn up the ocean. Another coastal storm would be suboptimal particularly so close in proximity to the Humberto/Imelda churn that we’re just moving past now.
Wave heights of 10 to 20 feet will be possible just offshore, assuming low pressure can develop off the Carolinas later this week. (Tropical Tidbits)
You can see the forecast wave heights from last night’s European model. This definitely is something to watch and monitor in the next few days for coastal folks in particular. The compounding effect of multiple storms in short proximity to each other can create some serious beach hazards and challenges on the oceanfront. More to come.
In brief: Invest 95L in the Atlantic is a ways from developing yet, and it currently looks to track north of the islands later this week. Still, we expect development eventually. Meanwhile, Tropical Storm Priscilla in the Pacific is worth watching in about a week or so for potential heavy rain in the Southwest.
Invest 95L
The Atlantic seems to be settling a little bit. That said, we have one very clearly defined system to watch this week. It is now known as Invest 95L.
Invest 95L looking a little disheveled for the time being in the eastern Atlantic. (Cyclonicwx.com)
From here, 95L will be slow to organize, but it should eventually hit a tipping point in a few days and probably form a tropical depression. From there, it will continue off to the west and west-northwest.
Model agreement is modest on actual development, but it’s in fairly strong agreement on track, taking it west-northwest toward the islands. (Polarwx.com/Tomer Burg)
Model agreement on this general theme is actually strong; there’s a little less uncertainty with this system than there has been with various systems of late. At this point, it seems likely that Invest 95L is going to turn north into the Atlantic before it gets to the Caribbean islands, but interests in the northeast Caribbean from Puerto Rico to about Martinique should continue to at least follow the progress of 95L this week. You can see from Google’s AI ensemble that over 90 percent of model forecast tracks stay north of the islands by Thursday night, but there are 1 or 2 that stay fairly close.
While one or two ensemble members track into the islands, at least on Google’s AI ensemble, the vast majority pass comfortably northeast of the islands later this week. (Weathernerds.org)
One other note: Unlike some other systems this year, this one is going to be booking it west northwest, and its closest pass to the islands should occur by Thursday.
So, at this point, there’s not a whole lot to worry about with 95L, but it remains an item to monitor this week as it tracks off to the west-northwest.
Pacific Priscilla impacts on the Southwest?
One other item we’ll be tracking through the week is the potential that Tropical Storm Priscilla in the Eastern Pacific could direct a bunch of moisture into the Southwest U.S. sometime next weekend or so. While Priscilla itself should not be a huge concern for land, the remnant moisture and all that comes with it will be what is watched. Current track forecasts for Priscilla keep it comfortably off the coast of Mexico as it strengthens into a hurricane this week. Once northward, it will begin to weaken, but it may also bend back to the northeast some.
Priscilla’s track density from Google’s DeepMind ensemble shows that it may bend back toward northwest Mexico and northern Baja toward the U.S. Southwest in a week or so as a remnant low. (Polarwx.com/Tomer Burg)
If this does happen, we could see it merge with an incoming trough of low pressure in the upper atmosphere around next week in the Rockies. That would draw most of the remnant moisture north and into the Southwest bringing some potential for locally heavy rain. This is highlighted on the Climate Prediction Center’s 8 to 14 day hazards outlook from Saturday.
(NOAA/CPC)
Not something to worry over or anything, but it’s something on our radar to watch for the next 7 to 10 days. We’ll keep it updated!
In brief: Today we discuss flooding risks in Florida from a disturbance, potential Atlantic development next week, and Storm Amy in Europe. We also look back at Humberto’s rapid intensification to category 5 status and place in the context of recent news stories about Katrina and Rita’s 20th anniversaries and evacuation planning.
All the quick hits
Atlantic tropics: Florida
Happy Friday. We’ll keep the weather part brief today. First, we have two areas remaining on the map now.
7-day development probabilities. (NOAA/NHC)
The area near Florida and the Bahamas remains unlikely to develop. It will, however, contribute to several days of rain chances on the Florida Peninsula. Flood Watches are now posted for the Space Coast and Treasure Coast.
(NWS Melbourne)
We also continue to see coastal flood watches and alerts posted from South Florida up into the Carolinas, including a Coastal Flood Warning in the Jacksonville area.
Heavy rainfall will add up to anywhere between 1 and 4 inches this weekend along the Florida coast. Urban flooding and flooding of low-lying areas is likely at times. And heavy rain may exacerbate coastal flooding concerns near places like Jacksonville.
Atlantic tropics: Next wave up
Looking out farther to the east, we have an uncommon late season Cabo Verde wave to watch over the next several days.
Next wave up! (Weathernerds.org)
It surely doesn’t look like much right now, but the models generally support a slow development from this area as it tracks west over the next 5 to 7 days. Everything at this point is speculative. This will almost certainly turn north and out to sea eventually, but the question is where. Will that happen before or after it gets to the northeast Caribbean? If before, we’re all good. If after? Then we may be on storm watch in Puerto Rico and the northeast Leeward islands in about a week. For now, it remains something to watch but nothing we can really say much more about yet.
Storm Amy in Europe
The significant early season storm impacting the UK and Europe more broadly is blowing through the region this evening.
Storm Amy on satellite pushing across the northern UK. (EUMETSAT)
Per the BBC, the storm has cut power to 50,000 in the northern UK. Train service is on hold in Northern Ireland, and Glasgow’s Central station is closed through Saturday afternoon. Winds will continue across the UK into Saturday, even as most of the rain has pushed east of the region. Tiree, off Scotland’s west coast reported a 96 mph wind gust from the storm. Additional weather warnings pepper the southern portion of Norway, mainly south and west of Oslo with winds of 60 mph possible there as well. Conditions should begin to improve across most of the region later Saturday into Sunday.
Meanwhile, Imelda’s remnants continue to swirl in the open Atlantic. They will be gradually absorbed into the jet stream next week.
Looking back: Humberto’s intensification & applying its lessons to evacuation planning
Huumberto is now a part of Storm Amy in Europe, but it is probably instructive to look back at that storm, because there are lessons to take from its rapid intensification.
When Humberto was classified as a tropical storm on Wednesday, September 24th, the initial model spread of intensification showed a wide range of outcomes by Saturday evening the 27th, with most hinting at a Category 1 or 2 storm.
Hour 72 would be Saturday evening, and the forecast from the various tropical models suggested a storm around category 1 or 2 intensity, with strengthening beyond that possible. (NCAR/UCAR)
From the first NHC advisory, it showed Humberto reaching the cusp of major hurricane intensity (110 mph) by Monday afternoon. By the Wednesday night advisory, that had nudged up to 115 mph, a category 3 major hurricane. Per the NHC, “The official intensity forecast is in reasonable agreement with the simple and corrected model consensus, including the latest FSU Superensemble forecast.” The subsequent Thursday early morning advisory didn’t make any meaningful changes, nor did it indicate much had changed. By late morning, the NHC had gotten more bullish on intensity, pushing it up to 120 mph, with emphasis being placed on the environment it would be in. In other words, as a frequent consumer of NHC discussion information, I would read between the lines and say that the latest model data with both the HWRF and HMON showing category 4 risk by Sunday morning had some merit.
Models still showed a wide intensity spread on Thursday morning, but they did nudge up the intensity risks a bit. (NCAR/UCAR)
From here, the forecasts gradually went upward, reaching 125 mph on Thursday’s late evening advisory and 130 mph early on Friday morning. It then jumped to 145 mph by late Friday morning, in line with model guidance.
Humberto’s intensity forecast gained further on Friday, with most model guidance at category 3 or stronger and several at category 4, nearing category 5. (NCAR/UCAR)
And the rest is basically history. Did anyone really expect Humberto would become a category 5 storm before Friday or even Saturday? Probably not. Did model guidance handle it well? It got better with time, as you’d hope. The NHC seems to have beaten most of the model guidance on Thursday into early Friday, and forecasters that read the NHC discussions (as all should) would have been tuned into their language being escalated. We will wait for the statistics to see just what did best during Humberto, but the NHC did a fine job raising the bar of concern with its intensity.
Now, given that Humberto was a secondary concern to Invest 94L and PTC 9/TD 9 at the time, it felt like this was all an afterthought. But I think it speaks again to the struggle we have with rapid intensification of storms. We’ve gotten so much better at this, but we still have a long way to go. We’ve seen so many storms in the Gulf rapidly intensify up to landfall in recent years. Will the East Coast have to face this eventually too?
With the 20th anniversary of Katrina and Rita in the news recently, the topic of evacuation has come up a bit. Recall that in Hurricane Rita over 100 people died during the evacuation alone. Forecasts have improved dramatically since then. But intensity forecasts and track forecasts are still imperfect. And while population has generally increased all over the Gulf Coast (and East Coast), infrastructure spending is barely keeping up. A recent discussion on Sea Change from WWNO highlighted the concerns specifically in Gulfport, MS, an area that has rebounded nicely since Hurricane Katrina. Of course, some debate if it has been a fair recovery. But the issue now is that traffic is so bad on a normal day that if an evacuation is called, there is likely to be gridlock. It does not help that local officials refused comment on this story, as they need to be thinking proactively instead of reactively. Refusal to comment will be filled by a void of speculation that there is either a lack of preparation or care about this topic.
But those were timely and relevant discussion points. The point I want to drive home is that Humberto *again* showcases a situation where intensification outpaces the forecast. To this point, we have focused on this from a Gulf-centric perspective with Ida, Michael, Ian, Helene, and any other number of quickly intensifying monsters in recent years. But with warming oceans, especially in the Atlantic, these types of scenarios aren’t improbable for places like Florida’s East Coast (as we witnessed with Dorian a few years back) or Georgia or the Carolinas. An emphasis needs to continue to be placed on making sure everyone knows their evacuation zone and importantly when NOT to evacuate. That’s what bit everyone during Rita in Texas. With many, many new residents in coastal locations from places that may not have had much severe or extreme weather, the importance of understanding when to evacuate and when not to is another element of all this. And with storms periodically showcasing that the window for making decisions may be shorter than you think, we need to continue to emphasize these lessons.
In brief: Bermuda managed Imelda just fine based on reports today, and now Imelda heads out to sea. Storm Amy, which includes some influence from Humberto will hammer the Scottish Highlands with gusty winds this weekend. Two new areas of interest showed up today in the Atlantic, one near Florida (primarily a rainmaker) and the other in the central Atlantic (may be worth monitoring in the islands).
Hurricane/Post-Tropical Imelda
According to the Royal Gazette of Bermuda, the island managed to get through Imelda without a ton of trouble. No casualties and no serious damage were reported. “By all accounts, the resilience of our island and its people have withstood the test. Because that’s what we do.” Bermuda gets hit fairly often, so they’re generally well-prepared for storms like this, and it’s not surprising that even a fascinating, challenging storm like Imelda was taken in stride there.
(NOAA/NHC)
Imelda will now become post-tropical and head out to sea, weakening below hurricane intensity tomorrow. Tropical Storm Warnings will likely be discontinued this afternoon on Bermuda.
Humberto’s remnants and Storm Amy in the UK
From here, Imelda will slowly follow Humberto out to sea, though at this point, it is not expected to produce a significant storm for Europe like Humberto’s remnants will help fuel with Storm Amy. An Amber Warning for wind is posted for northwestern portions of Scotland from Friday evening through Saturday morning (UK time).
UK alerts for Storm Amy this weekend. (UK Met Office)
In the UK, warnings are issued on a yellow-amber-red scale, with red being the highest impact risk. In this case, amber warnings indicate significant risk but not necessarily the highest risk. According to the Met Office, “Storm Amy will bring a spell of damaging winds, initially in western areas during Friday evening before gradually transferring northeastwards through the night and into early Saturday. During this period, wind gusts of 60-70 mph are likely fairly widely, and may exceed 95 mph in more exposed areas. This is likely to lead to travel and power disruption.”
You can see on the European model how a small corridor of purple tracks just north of Northern Ireland, through the Outer Hebrides and into the upper reaches (Highlands) of Scotland.
Strong winds associated with Storm Amy will track across the Outer Hebrides & Scottish Highlands. (Weathernerds.org)
So this will certainly be an impactful storm in this region.
Just a quick note on naming storms in Europe. Storms are named in Ireland, the UK, or Netherlands when they’re expected to cause significant impacts, “medium” or “high.” The BBC has a good article explaining why, how, and what the name list is for the upcoming cold season. Wind is the main concern with these storms, but they also look at other impacts too. In Amy’s case, the amber warnings are only posted for wind.
Rest of the tropics
With Humberto and Imelda exiting the outlook, we replace them with two new participants today! Please welcome a 10 percent area near Florida and a 20 percent area in the open Atlantic.
(NOAA/NHC)
Starting in the Atlantic, this area is showing a 20 percent chance of development next week, mainly east of the islands. We’re a long way out, however there is actually good model agreement on some kind of organization in the central Atlantic by midweek next week.
Models showing decent development risk in the central Atlantic by next week. Above, you see various Google AI model ensemble members and the classic European ensemble model, with a fairly strong signal somewhere east of the islands. (Google Weather Lab)
We have a long way to go with this one. Eventually, like most Atlantic activity this time of year, the system, should it develop will likely turn out to sea. Where that happens is TBD. So, for folks in the Caribbean islands, it’s a good idea to check back in on this in a couple days to see where things stand.
Closer to home, there is a low-end chance of development near Florida. Models are mostly unexcited by this area in terms of possible tropical development. However, there is a strong signal for locally heavy rainfall on the coast of Florida. In fact, the next week or so could see close to double digit rain totals on Florida’s east coast.
The rainfall forecast for Florida over the next week. (Pivotal Weather)
There will likely be some urban flooding concerns from time to time, especially between Fort Lauderdale and Daytona. The overall pattern would support a slow northwest drift to any low pressure that develops. This will also keep persistent onshore flow going in Florida. That leads to rip currents, rough surf, and generally hazardous marine conditions in Florida.
Rip currents, rough surf, and gusty winds will pepper the Florida coast over the next several days. (NWS Miami)
If you’re vacationing in Florida this weekend, just be advised to use caution if you venture into the water.
We’ll keep tabs on this one in the coming days to ensure nothing funky happens.
