bdgwx

Unfortunately I cannot find a copy of this newly published study that isn't behind a paywall. But it is said that it supports a 2035 target for the first ice-free summer according to news articles.

https://www.nature.com/articles/s41558-020-0865-2

Hmm...maybe this is my misunderstanding but I was under the impression that sea ice would tend to cling to the northern coast of Greenland for decades to come and possibly through the remainder of this century even during the summer. But after seeing the substantial reductions in this area in 2020 I'm now obviously questioning that assumption. I was also an advocate of more moderate estimates of the first "ice-free" summer tending to favor 2050 or so. Again...I'm starting to question my position in this regard as well. 

16 minutes ago, csnavywx said:

Big dipole to start the month, relaxed a few days later and then a monster Greenland ridge centered around the 12th. That pattern relaxed into a strong +PV for a while with a weaker dipole event to end the month. GAC strikes at the end of the first week of August and by that point is able to sweep away most of the low-extent ice. Overall the first half is dominated by storminess, with a return to Greenland ridging and a dipole-like pattern to finish the month.

Most of the damage is done with the early June and early July dipole events (with the mid-July Greenland ridge pattern no doubt helping export).

Gotcha. Thanks. That's helpful. I try to lurk as much as I can on the Arctic Sea Ice Forum. Sea ice is such a complicated beast to understand.

I'm still trying to learn the ins and outs of Arctic sea ice. I've gotten a pretty good understanding of some of the things that negatively affect the ice. 

What was the pattern like in July and August of 2012?

ERA 2mT reanalysis is +0.627 for May. This is the warmest May on record.

https://climate.copernicus.eu/surface-air-temperature-may-2020

NCEP/NCAR 2mT reanalysis was -0.08C from April to May. UAH's TLT product doesn't always move in tandem with the surface temperature. In fact, it often moves in the opposite direction.

BTW...I just recently learned that UAH's TLT product is actually derived from their MT, TP, and LS products. Specifically the weighting is LT = 1.538*MT + -0.548*TP + 0.01*LS. I've mentioned this before, but I wonder how much the stratospheric cooling is contaminating their TLT product.

https://www.drroyspencer.com/wp-content/uploads/APJAS-2016-UAH-Version-6-Global-Satellite-Temperature-Products-for-blog-post.pdf

That's pretty cool. Which reanalysis dataset are you using?

Here is an update of the CMIP5 vs observation comparison as of March/2020. 

CarbonBrief

3 hours ago, BillT said:

why was that period cherry picked to use as the baseline?    because it was a cooler period?

That's what the GISS group wanted to do. Other groups use different baselines. All it does is to make a baseline from which the anomalies are computed. You can pick any baseline you want. It can be an entirely arbitrary decision. It does not change the ranking of the years, the warming trend, or the structure of the graph chubbs posted.

That April 2020 update from UAH brings their trend up one notch to +0.14C/decade now. For comparison Berkeley Earth is +0.19C/decade, RSS is +0.21C/decade, and ERA is +0.19C/decade over the same time period.

One thing to take note of with this event is that the big 3 global models are all robust with thermodynamic and kinematic environment even with the low levels.

4 consecutive SREF runs show a 90 contour surrounded by an expansive 75 contour on the tornado ingredients product even though the event is more than 48 hours away.

CIPS analog guidance has 3 high risk days in the list including 2007-03-01, 2010-04-24,  and yes 2011-04-27 is there too.

You guys beat me to it. I was just going to post the SREF tornado ingredients product myself. A 90 contour at F72 is rare indeed.

The globals (GFS, UKMET, and ECMWF) have the high risk style look to them. And there's already a 60 contour showing up on the SREF tornado ingredients product. That's pretty high for the FH81 frame. There's not a whole of lot data to constrain this event at this point in time. 

I'm usually pretty conservative when guessing at the risk outlooks...sometimes too much so...but yeah, if tonight's global runs are not materially different than today then I too would not be surprised by a D3 moderate from the SPC tomorrow.

UAH also recorded another increase in stratospheric temperatures. If history is any guide then that means further troposphere cooling is around the corner. The leading hypothesis for stratospheric warming is still wildfire smoke.

The radar returns on that convective complex are starting to wane. It's possible this lays out a boundary that backs the surface winds and enhances the critical angle on the hodographs. It's more of a low probability and speculative scenario, but the 14Z HRRR does kind of hint at that. Instability would still have to materialize of course. If it happens just right the MO/IA/IL border area might still be a prime spot.

It may not be as focused or as certain as it appeared last night, but odds still favor a significant outbreak including tornadoes. The SPC is still pushing EF2+ tornadoes today afterall. 

3Z SREF suggests only modest tornado potential in western/northern IL. Verbatim the higher tornado probabilities are in AR/MO/TN/KY/IL border area. If I were to go off only the latest HRRR and SREF runs I think I'd be considering a downgrade right now. But...it's a big low with an impressive kinematic environment so maybe they'll decide to keep the 15% sig-tor area on the 13Z update and wait and see what the morning convection does before making big adjustments. I will say that the 10Z HRRR still has a pretty good parameter space in IL just on a more localized scale now.

I don't know about the high risk. HRRR looks potent now, but what will things look like tomorrow? We've seen this type of over-reaction by CAMs only to curtail their outputs a few runs later or the day-of ends up being a bust. Nah...I see < 50% of a high risk tomorrow. I'll accept a good ribbing if I'm wrong though. We'll see.

^^^ 3km CAPE of 237, LCL of 372, and 1km SRH of 274. Yikes.

Those UH tracks on the 0Z HRRR are gnarly. They're also expanding at a rate of 65 mph.

Man...I'm getting up to 70 mph right movers on some of these soundings.

15Z RAP is primed with a convective melee of activity in the warm sector there in IL.

Another day and another sharp decline. The NSIDC did call the top as March 5th.

March 5 with a 5d average of 15.047 on NSIDC might be the max. I'd give greater than 50% odds at this point. We'll see.

On 3/5/2020 at 6:33 AM, chubbs said:

Will need to see more evidence re; smoke/volcano. Spencer is missing the two obvious factors for UAH warmth: GHG and improved satellites with no diurnal drift. Evidence for the last point is the UAH trace - the period after the 2016 nino is much warmer relative to the super nino peak than the period after the 1998 nino. What happened in 1998? the MSU to AMSU transition. Scientists still don't know which satellite was right NOAA-14 or NOAA-15. UAH picked the colder satellite, of course, which looks like the wrong choice when compared against other series. Meanwhile per the article below, recent satellites have essentially no diurnal drift, with very stable performance for climate detection.

https://advances.sciencemag.org/content/4/10/eaau0049.full

 

RSS was up in February, but not as much. ERA was only up by 0.02C. I keep wondering if UAH is contaminated by what happens in the stratosphere more so than RSS. If so that would partly explain UAH's 0.13C/decade trend which is far lower than what any other dataset shows.