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

[DorkyMcDorkface]

http://twitter.com/AndyHazelton/status/1390782816758140933?s=20

Little interesting that the PDO and PMM look more negative than last year. Would be a plus for the Atlantic should it verify as convection over the Eastern/Central Pacific likely wouldn't be as enhanced, thus lessening shear. Suppose that may be one thing this year may have over last year (although granted it really didn't make much of a difference last season as the Niña proved to be suppressive enough in the EPAC in its own right).

[Shell Mound]

The latest NMME for ASO 2021 is almost a perfect match relative to the years that featured major-hurricane landfalls on metropolitan South Florida. Note the below-average precipitation anomalies over the northwestern Caribbean, the western two-thirds of the Gulf, and the Great Plains region (due to heat ridging). Bermuda is also drier than normal due to a strong, west-based Bermuda High, as is the Upper Midwest (Great Lakes region). The NMME is clearly indicating a kind of “ridge-bridge” similar to that in the years that featured MH strikes on South FL. This is clearly different from the pattern projected for ASO 2020, but matches the ESRL composite for years with MH impacts on South FL.

[SFLcane]

https://www.cpc.ncep.noaa.gov/products/NMME/archive/2020050800/current/images/NMME_ensemble_prate_us_season3.png
https://www.cpc.ncep.noaa.gov/products/NMME/current/images/NMME_ensemble_prate_us_season3.png
https://i.postimg.cc/g2Pswm86/FLprecipitation-1.png

The latest NMME for ASO 2021 is almost a perfect match relative to the years that featured major-hurricane landfalls on metropolitan South Florida. Note the below-average precipitation anomalies over the northwestern Caribbean, the western two-thirds of the Gulf, and the Great Plains region (due to heat ridging). Bermuda is also drier than normal due to a strong, west-based Bermuda High, as is the Upper Midwest (Great Lakes region). The NMME is clearly indicating a kind of “ridge-bridge” similar to that in the years that featured MH strikes on South FL. This is clearly different from the pattern projected for ASO 2020, but matches the ESRL composite for years with MH impacts on South FL.

Great post but remember 2020 was pretty wet over Florida on NMME. Also magnitude of wetness looks quite small in 2021

[Category5Kaiju]

https://www.cpc.ncep.noaa.gov/products/NMME/archive/2020050800/current/images/NMME_ensemble_prate_us_season3.png
https://www.cpc.ncep.noaa.gov/products/NMME/current/images/NMME_ensemble_prate_us_season3.png
https://i.postimg.cc/g2Pswm86/FLprecipitation-1.png

The latest NMME for ASO 2021 is almost a perfect match relative to the years that featured major-hurricane landfalls on metropolitan South Florida. Note the below-average precipitation anomalies over the northwestern Caribbean, the western two-thirds of the Gulf, and the Great Plains region (due to heat ridging). Bermuda is also drier than normal due to a strong, west-based Bermuda High, as is the Upper Midwest (Great Lakes region). The NMME is clearly indicating a kind of “ridge-bridge” similar to that in the years that featured MH strikes on South FL. This is clearly different from the pattern projected for ASO 2020, but matches the ESRL composite for years with MH impacts on South FL.

Great post but remember 2020 was pretty wet over Florida on NMME. Also magnitude of wetness looks quite small in 2021

If I recall correctly last year was way wetter over the Western Gulf than Florida, at least the precip prediction maps frequently displayed that

[Shell Mound]

https://www.cpc.ncep.noaa.gov/products/NMME/archive/2020050800/current/images/NMME_ensemble_prate_us_season3.png
https://www.cpc.ncep.noaa.gov/products/NMME/current/images/NMME_ensemble_prate_us_season3.png
https://i.postimg.cc/g2Pswm86/FLprecipitation-1.png

The latest NMME for ASO 2021 is almost a perfect match relative to the years that featured major-hurricane landfalls on metropolitan South Florida. Note the below-average precipitation anomalies over the northwestern Caribbean, the western two-thirds of the Gulf, and the Great Plains region (due to heat ridging). Bermuda is also drier than normal due to a strong, west-based Bermuda High, as is the Upper Midwest (Great Lakes region). The NMME is clearly indicating a kind of “ridge-bridge” similar to that in the years that featured MH strikes on South FL. This is clearly different from the pattern projected for ASO 2020, but matches the ESRL composite for years with MH impacts on South FL.

Great post but remember 2020 was pretty wet over Florida on NMME. Also magnitude of wetness looks quite small in 2021

If I recall correctly last year was way wetter over the Western Gulf than Florida, at least the precip prediction maps frequently displayed that

Compared to April’s, May’s NMME is notably wetter over the Caribbean and the southwestern North Atlantic, including the Greater Antilles and the Bahamas:



Also, as mentioned previously, the precipitation pattern on May’s run closely resembles that of years with major hits in South FL (note the dry GoM):


Additionally, note that May’s NMME has trended toward more of a +TNA vs. April’s run, despite overall SST being cooler (yet note the cooler NW Atlantic):



Note the trend, however subtle, toward an +AMO-aligned SST configuration over the northwestern North Atlantic, that is, the subtropics.

[SFLcane]

Get ready Florida!

 https://twitter.com/bennollweather/status/1391075925979123717

[Shell Mound]

Get ready Florida!

https://twitter.com/bennollweather/status/1391075925979123717

 https://twitter.com/BenNollWeather/status/1391060826258165764



 https://twitter.com/BenNollWeather/status/1391030627382661126



 https://twitter.com/cyclonicwx/status/1390761407113740288



 https://twitter.com/AndyHazelton/status/1390827965437579270



The -IOD could actually mean a more active MDR vs. 2020, given a weaker African monsoon → more compact storms develop faster, hence drier Caribbean.

[Kingarabian]

The recent IMME forecast should be used with some caution. One member has a super La Nina which is very unlikely this year, and as a result has the skewed the forecast.
 https://twitter.com/webberweather/status/1390762706408337408

[Iceresistance]

The recent IMME forecast should be used with some caution. One member has a super La Nina which is very unlikely this year, and as a result has the skewed the forecast.
https://twitter.com/webberweather/status/1390762706408337408

When was the last time that a Super La Nina existed?

[Category5Kaiju]

The recent IMME forecast should be used with some caution. One member has a super La Nina which is very unlikely this year, and as a result has the skewed the forecast.
https://twitter.com/webberweather/status/1390762706408337408

When was the last time that a Super La Nina existed?

2010 I believe. 2007 was also a quite potent La Nina, although if you are wondering the last time we had a La Nina that lasted for more than 2 years was in 1998, going from that year to nearly 2001.

[Iceresistance]

The recent IMME forecast should be used with some caution. One member has a super La Nina which is very unlikely this year, and as a result has the skewed the forecast.
https://twitter.com/webberweather/status/1390762706408337408

When was the last time that a Super La Nina existed?

2010 I believe. 2007 was also a quite potent La Nina, although if you are wondering the last time we had a La Nina that lasted for more than 2 years was in 1998, going from that year to nearly 2001.

Yes, the 2010 La Nina is the strongest recorded, but, I've noticed a pattern.

Every Decade or so, there is a Double La Nina (1998-1999 & 1999-2000) & (2010-2011 & 2011-2012)

Could this be the next Double La Nina?

[Kingarabian]

When was the last time that a Super La Nina existed?

2010 I believe. 2007 was also a quite potent La Nina, although if you are wondering the last time we had a La Nina that lasted for more than 2 years was in 1998, going from that year to nearly 2001.

Yes, the 2010 La Nina is the strongest recorded, but, I've noticed a pattern.

Every Decade or so, there is a Double La Nina (1998-1999 & 1999-2000) & (2010-2011 & 2011-2012)

Could this be the next Double La Nina?

I think it's possible again this year. 2016-2017, albeit weak. was also a double dip La Nina

[Category5Kaiju]

What I personally am actually more interested to see is when the next true El Nino would occur; the 2018-2019 one was, while almost a moderate El Nino at its peak at roughly 0.9 C if I am not mistaken, it unexpectedly died in the summer of 2019, and so this makes 2015 the last actual El Nino year. I would think next year is somewhat likely to feature an El Nino, although I (as I have said before) am not sure if future WAMs would actually impact the strength and dynamics of these Ninos assuming recent patterns hold.

[NDG]

We usually start seeing signs of what the over all pattern will be like during the hurricane season later in May and June.
If the NAO stays mostly negative like it has so far this Spring I would expect a lot of OTS storms east of Bermuda, the reason why the NMME shows a drier eastern Caribbean.

[Shell Mound]

[Steve]

We usually start seeing signs of what the over all pattern will be like during the hurricane season later in May and June.
If the NAO stays mostly negative like it has so far this Spring I would expect a lot of OTS storms east of Bermuda, the reason why the NMME shows a drier eastern Caribbean.

I know weatherbell addressed the trough in the NEUS and NWAtl for May and said it would migrate with high pressure moving into that area during the heart of the hurricane season (thus their forecast for a lot of hits on the US again).

?

[cycloneye]

Much cooler MDR in 2021 than in 2020 for this time of year. We will see how things evolve in the next 3 months.

[toad strangler]

Much cooler MDR in 2021 than in 2020 for this time of year. We will see how things evolve in the next 3 months.

A cooler MDR IRT average could help waves and or pouches to meander further W than they should to terrorize those downstream.

[CyclonicFury]

Much cooler MDR in 2021 than in 2020 for this time of year. We will see how things evolve in the next 3 months.

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

https://i.imgur.com/iwnGPf1.png

That is the 7 day change, not the current SST anomaly, and the CDAS tends to run cooler than other datasets. Regardless, the MDR is cooler than 2020.

[Shell Mound]

Much cooler MDR in 2021 than in 2020 for this time of year. We will see how things evolve in the next 3 months.

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

https://i.imgur.com/iwnGPf1.png

That is the 7 day change, not the current SST anomaly, and the CDAS tends to run cooler than other datasets. Regardless, the MDR is cooler than 2020.

Enhanced low-level easterlies (trades) over most of the MDR have certainly been playing a key role over the past month. Interestingly, the NAO has been strongly negative, albeit west-based, during the same timeframe. Perhaps the expansion of Hadley cells due to climate change means that in the near future -NAO episodes will not correlate as strongly with a warmer MDR, due to the low-level westerlies shifting northward into the subtropics, to be supplanted by net easterlies underneath. Regardless, the SST configuration in the remote North Atlantic, particularly to the immediate south of Iceland, recalls that of a -AMO rather than +AMO, given abundant freshwater intrusion from Greenland vis-à-vis AGW feedback → freshening of the North Atlantic Deep Water (NADW) → weakening of the Atlantic meridional overturning circulation (AMOC).