2023 Tropical Weather

[Taylor Campbell]

 

[JPWX]

Must be getting close to August

 

[Casuarina Head]

So far El Niño does not seem to have exerted much influence on the Atlantic, but the subtropics are notably warmer than the Main Development Region (MDR). OISST shows anomalies of +1.3–1.4°C in the MDR yet +6°C or more (!) off Newfoundland. As we witnessed last year, this could lead to problems with sinking air and PV streamers in the deep tropics, even if El Niño somehow remains a minor factor during the peak of the season. In fact, the warm subtropics basically shut down the MDR in 2022, despite La Niña being robustly present, so a more active season during El Niño would seem unlikely. Given the warm subtropics I am personally still skeptical about the higher-end, “hyperactive” forecasts and would expect a near-to-below-average season. I personally believe that the two MDR-based cyclones in June were flukes (similar occurrences during +ENSO could have happened prior to satellite) and may have little bearing on the rest of the season. The -PDO/-PMM setup in the NW Pacific, along with the absence of a Niño-like oceanic-atmospheric interface, could mean that we may witness average-to-below average activity in all three NHEM basins, however. I could be wrong.

 

[Casuarina Head]

^ The preceding collage shows significant SST changes within the past month. Note that the Canary Current seems to have strengthened, resulting in cooling over the eastern subtropical Atlantic. Along with cooling west of the British Isles, this indicates less of a +AMO than seen a month ago. The fact that the Gulf of Mexico and Eastern Seaboard show higher + anomalies than the Caribbean also does not comport with a prototypical +AMO, in which the Caribbean is typically warmer than the former two regions. Taken together, all these trends might allow more mid-latitude dry air to infiltrate the deep tropics, resulting in greater stability and reduced intense TC activity during the peak of the season. The possible impact of El Niño later on would make an already-hostile situation even more detrimental to major hurricanes in the MDR. If warm subtropics singlehandedly overcame La Niña and shut down the MDR last year, similar warmth during El Niño would logically be even more inhospitable.

 

[Taylor Campbell]

The disturbance in the central Atlantic still looks poised to become something formidable. There’s a lot of support for it to go out to sea.

 

[tmcwx]

I believe we now have a higher probability of witnessing this 20% likelihood of development just south of Jackson since the water temperatures are looking a bit warmer!
The second storm of the year could be more fascinating than the first.

 

[tmcwx]

In the subtropical eastern Atlantic, temperatures have dropped as a consequence of the Canary Current's apparent strengthening. This, together with the recent cooling west of the British Isles, points to a weaker +AMO than was seen a month ago. As the Caribbean is usually warmer than the Gulf of Mexico and the East Coast, the fact that these places exhibit larger + anomalies than the Caribbean is likewise inconsistent with a normal +AMO. All of these changes combined may enable more dry air from the mid-latitudes to penetrate the deep tropics, leading to increased stability and less severe TC activity during the height of the season. El Nio's potential future influence would exacerbate an already unfriendly environment for large storms in the MDR. If last year's El Nio was able to overcome La Nia and shut down the MDR on its own, then it stands to reason that comparable temperatures during El Nio would be much more unfriendly.

 

[Casuarina Head]

I often wonder whether the AMO should be calibrated differently. Even if anomalies in the AMO-based regions are technically positive—a feat that is easier to achieve in an era of global warming—if the warmest anomalies are in the subtropics, the deep tropics tend to struggle to generate hyperactivity ACE-wise. In order to get an +AMO-type atmospheric response, all other factors being equal, the strongest + anomalies need to be in the “horseshoe” from Greenland to the Canaries and thence down into the MDR and Caribbean, not in the Gulf of Mexico or along the Eastern Seaboard (including the Canadian Maritimes). Since 2005, and particularly since 2012, we have had plenty of seasons that technically met +AMO criteria SST-wise, but featured the warmest + anomalies outside the deep tropics and thus ended up with an -AMO-like response, e.g., less seasonal ACE in the deep tropics than one might otherwise expect in an +AMO. During these kinds of setups the intense, long-tracking major hurricanes are often less frequent in the MDR and/or Caribbean, owing in part to the greater stability and shear that anomalous warmth in the subtropics generates farther south.

 

[Casuarina Head]

Here I offer some examples of prototypical +AMOs. In each of the following note that the warmest + anomalies occur in a “horseshoe” from Greenland to the Canary Islands and thence into the MDR and Caribbean. Note that the Gulf of Mexico, Eastern Seaboard, and Maritimes feature either a) cooler-than-average anomalies or b) + anomalies that are still cooler than the + anomalies in the “horseshoe”-shaped +AMO region. Several of these years occurred well prior to satellites (1960s on) and thus likely featured much higher ACE than is officially recorded, given that these years often coincided not just with very strong +AMOs, but also with -PDO/-ENSO combinations in the Pacific. 1878, 1887, 1891, and 1893 in particular likely featured much higher ACE than currently appears on official records, in some cases possibly competing with or exceeding record-breaking ACE-makers such as 1933 and 2005.

By contrast, most of the recent +AMO seasons since 2012 have featured their strongest + SST anomalies in the subtropics, not the MDR/Caribbean.

 

[Taylor Campbell]

Models have my attention in the long range period for potential tropical development north of the big islands in the Nares Plain region of the Atlantic.

 

[JPWX]

I'm more concerned about the Central Gulf Coast this season going forward than the East Coast. That is all.

 

[Casuarina Head]

I'm more concerned about the Central Gulf Coast this season going forward than the East Coast. That is all.

@JPWX Do you have any reason in particular? Perhaps a -NAO? Long-range forecasts? Some of the models do seem to support your outlook.

Personally, I would be a little surprised if one or more significant hurricanes were to impact the central Gulf Coast this year. Since 2016 the entire Gulf Coast between the Keys and South Texas has seen at least one Category-2+ landfall per state. The central Gulf Coast in particular has seen multiple such hits from 2020–1, including two or more majors. So the Gulf Coast is already climatologically “saturated.” In fact, the mainland U.S. in general has seen significant hurricane impacts nearly everywhere since 1995, except metropolitan Southeast Florida (Miami–Fort Lauderdale–West Palm Beach). Even the Mid-Atlantic region has managed to see eventful and/or strong hurricane impacts—e.g., Irene 2011, Sandy 2012, Isaac 2020—before Southeast Florida. Yet if any place is climatologically overdue, it is the Miami area.

Since 2016 alone no fewer than five Category-4+ hurricanes have narrowly missed Greater Miami to the east and west, respectively. No other comparable period since 1900 has featured so many close calls of such intensity yet not a single landfall; had these recent storms formed between 1926–69 one or more them would have likely hit Greater Miami, given the frequency with which Category-4+ storms that passed nearby actually hit the region head-on. During this previous +AMO cycle virtually all of the twenty-six Category-4+ storms that passed within 350 n mi or so of Greater Miami actually made landfall there or very close nearby; but since 2016 all five tropical cyclones that have done so missed. Sooner or later one of these intense storms seems likely to make a direct hit on metropolitan Southeast Florida.

 

[warneagle]

Models have my attention in the long range period for potential tropical development north of the big islands in the Nares Plain region of the Atlantic.

Had to look up where that is, my vacated middle school geography bee trophies are gonna be displayed alongside Reggie Bush's Heisman now

 

[JPWX]

00z Euro Ensemble showing my dream back on April 23rd of a category 5 in the Gulf.

Before you say that's just a dream, I dreamed 10 years ago about the EF3 that hit Amory MS this past March. Few years prior to the Smithville MS EF5 tornado on April 27th 2011, I dreamed about a tornado going right in front of my house in Smithville on hwy 25 North. I lived right off the highway. Literally right in front of it.

 

[Clancy]

00z Euro Ensemble showing my dream back on April 23rd of a category 5 in the Gulf.

Before you say that's just a dream, I dreamed 10 years ago about the EF3 that hit Amory MS this past March. Few years prior to the Smithville MS EF5 tornado on April 27th 2011, I dreamed about a tornado going right in front of my house in Smithville on hwy 25 North. I lived right off the highway. Literally right in front of it.

Geez, you should find a way to dream about cool, sunny days more often!

 

[JPWX]

Geez, you should find a way to dream about cool, sunny days more often!

Yes I've been told that. LOL!

 

[Casuarina Head]

00z Euro Ensemble showing my dream back on April 23rd of a category 5 in the Gulf.

@JPWX Where in the Gulf, if I may ask? (To be fair, I think that your “vision” may end up being correct. I shall explain further shortly.)

The central Gulf Coast in particular has seen two sub-950-mb landfalls since 2020, Laura and Ida, so that area hardly seems “due” for a third such impact. Additionally, the rest of the Gulf Coast has seen other sub-950-mb impacts such as Harvey/Irma (2017), Michael (2018), and last year’s Ian. Virtually the entire Gulf Coast has seen significant direct and/or indirect TC impacts since 2017. In terms of landfalls, only Greater Houston/Galveston and Tampa Bay have been comparatively spared, though Harvey flooded the former while making a distant landfall.

Did your dream suggest a long-tracking crossover, e.g., a major hurricane that crosses peninsular Florida first and enters the Gulf? If so, then maybe climatology would support some kind of high-end impact to metropolitan Southeastern FL and then Houston, TX. (For the sake of argument I am assuming here that something like this may transpire. If it were to do so, then climatology might suggest twin impacts, along the aforementioned lines.)

 

[JPWX]

@JPWX Where in the Gulf, if I may ask? (To be fair, I think that your “vision” may end up being correct. I shall explain further shortly.)

The central Gulf Coast in particular has seen two sub-950-mb landfalls since 2020, Laura and Ida, so that area hardly seems “due” for a third such impact. Additionally, the rest of the Gulf Coast has seen other sub-950-mb impacts such as Harvey/Irma (2017), Michael (2018), and last year’s Ian. Virtually the entire Gulf Coast has seen significant direct and/or indirect TC impacts since 2017. In terms of landfalls, only Greater Houston/Galveston and Tampa Bay have been comparatively spared, though Harvey flooded the former while making a distant landfall.

Did your dream suggest a long-tracking crossover, e.g., a major hurricane that crosses peninsular Florida first and enters the Gulf? If so, then maybe climatology would support some kind of high-end impact to metropolitan Southeastern FL and then Houston, TX. (For the sake of argument I am assuming here that something like this may transpire. If it were to do so, then climatology might suggest twin impacts, along the aforementioned lines.)

Eastern Gulf with just west of Mobile towards Tallahassee in the threat zone.

 

[Casuarina Head]

Eastern Gulf with just west of Mobile towards Tallahassee in the threat zone.

This is the same region that experienced 919-mb Cat-5 Michael only five years ago. Another C5 landfall in the same general region would be unprecedented. Besides Michael, only the 1935 Labor Day hurricane, 1969’s Camille, and 1992’s Andrew struck the CONUS as C5s, and none of these occurred within a few decades of each other, let alone five or fewer years. Moreover, only the hurricane of 1935 and Andrew struck the same general region, depending on whether one counts the Keys as part of the Gulf Coast or peninsular Florida.

To be fair, your “vision” may well transpire, but something like this would be extraordinary.

 

[Casuarina Head]

^ This image was made a few years ago. Since then Ian made landfall very close to Irma’s (2017) location. But the overall picture is clear that the Gulf Coast is certainly not “overdue” for another high-end landfall. Neither is most of the rest of the CONUS, other than New England. Besides the latter region, the only other part of the CONUS that is practically due for a major landfall is the east of peninsular Florida, particularly Greater Miami. One could argue that Sandy (2012) effectively counted as a major impact in New England (and/or the Mid-Atlantic), given its 945-mb pressure at landfall. If Sandy is counted, then only the east coast of FL is left, especially the Miami area.

^ Here are the Cat-4+ “near misses” (within 350 n mi) that have curved past metropolitan Southeastern Florida (MIA–FLL–PBI) since 2016.