2021 Indicators: SST's / SAL / MSLP / Shear / Steering / Instability / Sat Images

[cycloneye]

I notice that 2006 is mentioned a lot around here so here is that S2K poll.

2006 S2K Poll

[ClarCari]

I notice that 2006 is mentioned a lot around here so here is that S2K poll.

2006 S2K Poll

It appears that much of the predictions that season may have been a result of Calamity or Catastrophe effect. Not alot of people thought 2005 would be followed by a below average season. I feel like there were other indicators that people were overlooking even besides the ENSO that showed 2006 was not going to be so active.

I like to think we are better now. hehe
Most of the discussion of 2021 having a high chance of being very active are based off of indicators and precedent and there are more indicators and modeling available besides the ENSO this time around that point towards a stronger than normal likelihood of another very active season.

Was there a 2006 Indicators thread from way back when? It may be interesting to see how things looked then compared to now and see what may have been missed besides the ENSO.

[cycloneye]

MDR like a thundra. but is early. +AMO / +NAO?

 https://twitter.com/cyclonicwx/status/1365761779465412608

[SFLcane]

Yikes! Season will be here before you know it.

We will see how sst’s evolve

 https://twitter.com/bennollweather/status/1367490264181448712

[SFLcane]

 https://twitter.com/bennollweather/status/1368926477396316161

[cycloneye]

NMME precipitation forecast for ASO shows a dry Caribbean,GOM and part of MDR. Subtropics look humid.

[Shell Mound]

NMME precipitation forecast for ASO shows a dry Caribbean,GOM and part of MDR. Subtropics look humid.

https://i.imgur.com/kkXslpY.png

 https://twitter.com/BenNollWeather/status/1369201353780723717



That kind of pattern, ad verbatim, would suggest a lot of activity forming well to the east in the MDR and then curving OTS. Good news, if it persists.

[chaser1]

NMME precipitation forecast for ASO shows a dry Caribbean,GOM and part of MDR. Subtropics look humid.

https://i.imgur.com/kkXslpY.png

That kind of pattern, ad verbatim, would suggest a lot of activity forming well to the east in the MDR and then curving OTS. Good news, if it persists.

Right? Or at least a good number of recurves anyway.

If looking at the NMME solely, then a couple possible analogues could be 1981, 2006? Far E. Atlantic appears moist so less inclined to assume the "wave train" shuts off, so perhaps SAL or low to mid level humidity perhaps? Next question then goes to steering. I don't see anything to suggest a significant deviation from 2020 steering that would indicate broadly lower 500mb level heights over the far W. Atlantic/S.E. CONUS region. Right now, there's no current evidence to already suggest, but if playing devil's advocate..... perhaps a slightly weaker and west-shifted Azores High resulting in a season pattern of "split-tracks". One set of tracks recurving over East Central Atlantic with another more troublesome set of tracks being more traditional Cape Verde but quickly gaining latitude remaining primarily north of the Caribbean and moving WNW to NW into higher latitudes of the U.S. Eastern Seaboard. Honestly though, this is a ton of extrapolation from one singular NMME precip forecast for the heart of hurricane season over 5 months away. Plus right now, I'd have a hard time making an argument that prevailing LaNina conditions would result in "unfavorable" upper level winds throughout the Caribbean and GOM lower latitudes. That alone seems to break from that NMME map (with exception of May, June, July which that map does not address). All in all it's early, though I do find it fun to now start watching how the tea leaves (and pollen) begin falling in place over the upcoming months.

[aspen]

If that precipitation/moisture forecast verifies and the ITCZ is at a similar latitude in ASO 2021 as it was in ASO 2020, that could result in a peak season comparable to 2020: anything in the Caribbean is weak (weaker than Marco or Nana), while the MDR contains long-tracking storms, a mix of those that struggle (Rene) and those that bomb out into hurricanes or majors (Paulette, Teddy). However, if the ITCZ ends up at a more normal/further south latitude with this moisture configuration, we could see some stronger and longer-tracking Cape Verde systems, some potentially tracking into the Caribbean. An already strong storm entering a dry Caribbean would last a lot longer than an AEW or a weak TC. This kind of setup could yield a season that has more quality>quantity compared to 2020 in terms of the types of storms that form; more MDR storms have the opportunity to become stronger than in 2020, even if the Caribbean is not nearly as favorable.

This is all dependent on whether that forecast holds. Since ENSO is most probable to be neutral or even in a La Niña state by ASO, I’m surprised by the drier-than-average forecast for peak season Caribbean. Also, we still have a few months before we pass the Spring Predictability Barrier, so things could change drastically in either direction.

[Shell Mound]

NMME precipitation forecast for ASO shows a dry Caribbean,GOM and part of MDR. Subtropics look humid.

https://i.imgur.com/kkXslpY.png

That kind of pattern, ad verbatim, would suggest a lot of activity forming well to the east in the MDR and then curving OTS. Good news, if it persists.

...

Personally, I think 1954 and 2011 might make for decent analogues in terms of steering. The central Gulf Coast and New England are my “hotspots.”

[SFLcane]

NMME precipitation forecast for ASO shows a dry Caribbean,GOM and part of MDR. Subtropics look humid.

https://i.imgur.com/kkXslpY.png

That kind of pattern, ad verbatim, would suggest a lot of activity forming well to the east in the MDR and then curving OTS. Good news, if it persists.

Right? Or at least a good number of recurves anyway.

If looking at the NMME solely, then a couple possible analogues could be 1981, 2006? Far E. Atlantic appears moist so less inclined to assume the "wave train" shuts off, so perhaps SAL or low to mid level humidity perhaps? Next question then goes to steering. I don't see anything to suggest a significant deviation from 2020 steering that would indicate broadly lower 500mb level heights over the far W. Atlantic/S.E. CONUS region. Right now, there's no current evidence to already suggest, but if playing devil's advocate..... perhaps a slightly weaker and west-shifted Azores High resulting in a season pattern of "split-tracks". One set of tracks recurving over East Central Atlantic with another more troublesome set of tracks being more traditional Cape Verde but quickly gaining latitude remaining primarily north of the Caribbean and moving WNW to NW into higher latitudes of the U.S. Eastern Seaboard. Honestly though, this is a ton of extrapolation from one singular NMME precip forecast for the heart of hurricane season over 5 months away. Plus right now, I'd have a hard time making an argument that prevailing LaNina conditions would result in "unfavorable" upper level winds throughout the Caribbean and GOM lower latitudes. That alone seems to break from that NMME map (with exception of May, June, July which that map does not address). All in all it's early, though I do find it fun to now start watching how the tea leaves (and pollen) begin falling in place over the upcoming months.

Yeah that's what I would think - more MDR storms. But then it becomes a question of steering for individual cases.

[Shell Mound]

 https://twitter.com/BenNollWeather/status/1369366623916789765



The NMME accurately showed impacts to the Gulf Coast and the FL peninsula in 2017, five months in advance, based on precipitation shields. This year it is showing the exact opposite at the same lead. This indicates that the model guidance is likely foreseeing a steering regime that favours OTS tracks, all other factors being equal. However, the latest forecast does suggest closer passes to New England than at the same time in 2017, so maybe 1954 and 2011 could prove somewhat analogous to 2021.

[cycloneye]

NMME failed bigtime in 2017=Irma / Maria.

[chaser1]

NMME failed bigtime in 2017=Irma / Maria.

If using that tool to suggest that PR was in the "no risk zone", that's 100% Correct.

Did the NMME "generally" suggest genesis and overall track pattern.... i'd say yes. But to take that type of a forecast tool and use it as a literal suggestion where a hurricane "will" or "will not" strike is foolish. I mean c'mon?! For that given year the NMME had the Caribbean clearly in the dryer zone and this may well have been why Franklin, Harvey, Nate, and Phillipe were lesser threats while in the W. Caribbean. Puerto Rico was clearly at the border of where the NMME was predicting the boundary of "dry" and neutral conditions. The most that one might have been able to extrapolate from that NMME forecast in '17 is that it might seem that most activity should remain primarily to the north of Puerto Rico. Just goes to show what difference 100 miles can make though. NO long range forecast tool is that precise (even if broadly accurate for wet/dry conditions for large swaths of the W. Atlantic).

[Shell Mound]

NMME failed bigtime in 2017=Irma / Maria.

If using that tool to suggest that PR was in the "no risk zone", that's 100% Correct.

Did the NMME "generally" suggest genesis and overall track pattern.... i'd say yes. But to take that type of a forecast tool and use it as a literal suggestion where a hurricane "will" or "will not" strike is foolish. I mean c'mon?! For that given year the NMME had the Caribbean clearly in the dryer zone and this may well have been why Franklin, Harvey, Nate, and Phillipe were lesser threats while in the W. Caribbean. Puerto Rico was clearly at the border of where the NMME was predicting the boundary of "dry" and neutral conditions. The most that one might have been able to extrapolate from that NMME forecast in '17 is that it might seem that most activity should remain primarily to the north of Puerto Rico. Just goes to show what difference 100 miles can make though. NO long range forecast tool is that precise (even if broadly accurate for wet/dry conditions for large swaths of the W. Atlantic).

Exactly. I am only using the NMME to indicate general patterns, not the exact track of every single outlier. For general patterns, the NMME has proven reliable on a number of recent occasions, including in 2017, even if it failed to register the exact location of mean ± axes, owing to the absence of a few “outliers” from certain locations, i.e., Irma and Maria from the northeastern Caribbean. CrownWeather’s analogs are heavily weighted toward EC impacts north of the FL peninsula vs. the GoM or the northwestern Caribbean. 1899, 1996, and 1999 in particular stand out. So his years generally go along with my preliminary outlook, based on the NMME, that 2021 will generally favour mean tracks either OTS or northward along the EC into New England or perhaps the Outer Banks. Something like the Norfolk–Long Island hurricane (1824), Floyd (1999), or Irene (2011) may well be plausible. Maybe one of those storms will impact the Leeward Islands and/or Puerto Rico initially, similarly to Hurricane/Huracán San Ciriaco (1899). But on balance the analogs clearly favour tracks to the north of the Greater Antilles, with one or two impacting the northeastern Caribbean and/or the Bahaman archipelago first before heading toward the upper U.S. East Coast or OTS.

[CrazyC83]

How are we right now in the Atlantic for indices relative to 2006 at this point? I think that will be brought up still a lot as an analog.

[tolakram]

This is the indicators thread. Anyone is welcome to start a personal forecast thread and go on record as to how you think the season will progress this year and what you are looking at, rather than filling this thread with a bunch of personal forecasts.

[crownweather]

How are we right now in the Atlantic for indices relative to 2006 at this point? I think that will be brought up still a lot as an analog.

I did take a look at the ONI for 2006 and compared it to this year & to me, the ONI numbers this year are stronger than what we saw from late 2005 into early 2006.

During the NDJ period of 2005-06, we saw roughly a -0.8 ONI as compared to this year, which is -1.2. Now, for DJF 2005-06, the ONI was -0.9 as compared to this year, which is -1.1. All-in-all, the La Nina numbers this year look stronger as compared to 2006. With that said, if you look at the very quiet 1956 season, the ONI numbers were extremely similar to this year, but we still saw a quiet season with 12 NS & a 56.7 ACE.

[wxman57]

If I were to put any area as having less of a threat, it would be the eastern Caribbean from PR to Trinidad. It's very questionable as to whether the MDR will recover this year. It's been quite hostile for the past 3-4 seasons, leading to little in the way of significant storms in the deep tropics south of 18N.

By “significant,” I assume you mean major hurricanes. If so, then you are definitely correct, as 2018–20 has only seen MH Lorenzo (2019) in the MDR south of 18°N.

Teddy was pretty close, though. It was around the Cat 2/3 border less than a degree north of 18N. We can attribute 2020’s MDR struggles to the state of the ITCZ: rather far north and pumping out huge waves that took a while to consolidate.

Teddy, too, formed in the MDR and quickly moved north and strengthened. It didn't track westward to the Caribbean. If such hostile conditions continue east of the Caribbean, then the eastern islands may get another break this season.

Taking a look at SST anomalies, the eastern Atlantic has a cool anomaly near Africa vs. a warm anomaly last year. Generally, the MDR is cooler so far this year.

[CyclonicFury]

If I were to put any area as having less of a threat, it would be the eastern Caribbean from PR to Trinidad. It's very questionable as to whether the MDR will recover this year. It's been quite hostile for the past 3-4 seasons, leading to little in the way of significant storms in the deep tropics south of 18N.

By “significant,” I assume you mean major hurricanes. If so, then you are definitely correct, as 2018–20 has only seen MH Lorenzo (2019) in the MDR south of 18°N.

And Lorenzo quickly moved northward out of the MDR. Storms (hurricanes) are not surviving if they track westward into the Caribbean.

Why do you predict a hostile MDR every year?