Record Low Arctic Sea Ice for July; Quiet tropics
Last month, Arctic sea ice extent was the lowest ever recorded for any July in the 1979 to 2011 satellite record, according to the National Snow and Ice Data Center. Most of the ice loss occurred in the first half of the month when high pressure made for clear skies and melting sunshine, and warm air blew into the Arctic from the south. In the first two weeks of July, air temperature over the North Pole was 11 to 14 degrees Fahrenheit above average. During the last two weeks of July, low pressure took over and brought cooler temperatures, although it appears this also acted to push the ice around, which resulted in a larger but thinner area of ice. New research shows that old ice continues to decline as well, which is problematic because older ice is more stable and tends to grow thicker over multiple seasons, and new ice is thin and more susceptible to melting. According to the University of Washington Polar Science Center, Arctic sea ice volume was 51% lower than average and 62% lower than the maximum (which was seen in 1979 at the beginning of the record).
Figure 1. Monthly July ice extent from 1979 to 2011 from the National Snow and Ice Data Center shows a 6.8% decline per decade.
The low amount of sea ice along Siberia has opened up the Northern Sea Route early (figure 2), and some companies are already taking advantage. It doesn't appear possible to get through the whole passage without the aid of an ice breaker or two around the East Siberian Sea, but compared to the normal route south through the Mediterranean and Indian Ocean, it's a deal. From Yokohama, Japan to the Rotterdam port in the Netherlands, the route through the Arctic is around 8,500 miles. If the Arctic is impassable, the route through the Pacific, Indian, and Atlantic oceans is around 13,000 miles.
Figure 2. Sea ice concentration from the University of Illinois Polar Research Group. Image modified to highlight the Northern Sea Route in light blue.
Quiet Tropics
After a brief reformation over the weekend as a tropical depression, Emily finally dissipated for good on Sunday, and the National Hurricane Center issued its last advisory on the system. The 7-day precipitation accumulation for July 30th through August 5th (figure 3) shows us that most of Hispaniola and eastern Cuba dodged the widespread, extreme rain that could have fallen had Emily stayed organized. Locally high accumulation of 5 to 15 inches fell in the Dominican Republic, which was probably aided by topography, but it does not appear that heavy, widespread rain fell in Haiti. The southeast Bahamas also might have also seen some relatively heavy rain (1.5 to 5 inches) from the system as it redeveloped thunderstorm activity north of Cuba late last week.
Figure 3. Satellite-estimates precipitation in millimeters for the 7 days preceding Friday, August 5th. Data provided by the Climate Prediction Center.
Beyond Emily, we're seeing a typical upswing in African easterly wave activity for August. Out in the main development region of the Atlantic, between Africa and the Caribbean, we have two waves, one near 50°W and the other around 25°W. Neither of these waves are forecast by any models to develop into tropical cyclones at this point, but the National Hurricane Center did invest the eastern wave over the weekend as 92L. They're no longer updating that invest as of yesterday afternoon, since satellite presentation degraded and the GFS stopped developing the wave. Even though they aren't favored to develop, what these systems might provide is a primer for waves that have yet to leave Africa. The next two waves, scheduled to enter the Atlantic around August 11th and August 15th, are looking slightly more favorable, although model support has waned since last week. This is expected though—its hard to get consensus and consistency from models on waves that have yet to enter open water. We'll know more at the end of this week, for sure.
Angela
Reader Comments
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Not something to try when your on cheap pharmaceuticals... made me dizzy.
Or 1923 Labor Day cane in the Keys when someone blew off a telegraph report from a forecaster in Cuba about a storm headed their way............
That is quite a surprise, thanks!
This is the time to make sure you have your La Nina preparedness kit ready.
What will the implications be in terms of our season I wonder?
La Niña usually increases tropical cyclone activity in the Atlantic basin. If it comes in the month, or after the month, of September, we may be seeing an abnormally active OSD (October-November-December).
That will happen when sharks start walking...
Strange is good... keeps things interesting.
thanks for the links earlier. sorry for the dumb question but why is everyone talking about going back to La Nina? It seems that we are in a fairly strong ENSO neutral pattern
Issued on Wednesday 3 August | Product Code IDCKGEWWOO
Neutral ENSO conditions persist in the tropical Pacific, with most atmospheric and oceanic indicators at near normal levels. Pacific Ocean temperatures have cooled over the last month, but remain within neutral thresholds. Atmospheric indicators of ENSO such as trade winds and cloudiness near the date-line have fluctuated around normal.
The majority of international climate model forecasts of ENSO show that neutral conditions are likely to continue for the remainder of the southern winter and into spring with the chances of an El Niño developing now considered unlikely. In fact, more models are now predicting further cooling over the coming season
From the Aussies last week. Possible bias emerging towards La Nina but with the "time lag" issue, not sure if it will impact our H-Season. Something worth keeping an eye on over the next two months.
thanks for these diagrams. so you are basically saying that in approx 240 hours (10 days), ridging will dominate the western atlantic again?
Do you mean that the High will relocate further to the NE and pose a landfall threat for the SE CONUS?
Just trying to understand what you are saying, thanks
On another note, can you shed some light on all the talk about the ridging and troughing?
sounds like from what Levi was saying (maybe same as you), the strong ridging pattern begins to take place in approx 240 hours according to the pictures he posted (see post 925)
Is he saying that the High will move NE? Sorry if this is a repetitive question but just trying to learn from you guys
In answer to your question regarding as to how the
pre-computer model forecasters found and predicted tropical cyclones, so I did a little research:
Early in the 20th century, the country was divided into prediction zones. For example, S.E. FL was
zone 1, West Coast FL, zone 2, and so on. At each zone were several stations with operation staff and a zone comander. The zone comander at each station played pivital role in protecting the nation and surrounding island nations.
Each zone comander had a very sensitiv bunion, and when it got sore, he would rate the pain on a scale fromm 1 to 5. He would then telegraph his counterparts in the other zones to see if they also were experiencing bunional discomfort (BD)
If his neighbor, lets say to the north, had BD, then he would relay the information up or over the coast, until he found a zone comander that suffered no or little BD. Next, they would rate their BD on a scale from 1 to 5, thus ascertaining not only that a tropical cyclone was imenenantly forming, but also the category and strengh of the storm.
"I suppose an early precursor to today's 1 to 5 category system". If swelling accompanied the BD, they would note that as well, because that swelling usually indicateded the amount of tidal surge, or swell, if you prefer to be expected.
One of the more famous and well respected zone comanders was a man named Dr. Scholtz, who later formed a company that built lighting rods. He was electricuted while demonstrating a new taller and rigid lighting rod at the 1920 world's fair in San Francisco. Ironically not by a lighting strike, but while screwing in a light bulb to read his own notes on his invention. His tropical storm work was continued by his assistant and close friend, Thom Mcan.
I hope this sheds some light on your question.
Of course feel free to press ignore now, as I obviously have way to much time on my hands.
Back to work....
It really is sad that while people in the central US are struggling with wildfires because of circumstances out of their hands, that young people over here in the UK see fit to start fires.
Link
Too late...
Link
Thats where they hide the aliens.
is this is basically showing strong bermuda high?
Yes, I'm sick of Emily already
looks at the high
lol JK JK
http://weather.unisys.com/hurricane/atlantic/2011 /index.html
Sorry work system would not let me give you a click on link
RE-RE!!!!!!!!!!!!!!!!!!!!!!
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