Colin takes aim at Bermuda; the Great Russian Heat Wave of 2010: 102°F in Moscow

By: Dr. Jeff Masters , 2:45 PM GMT on August 06, 2010

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A reborn Tropical Storm Colin is taking aim at Bermuda, and should bring tropical storm force winds to the island by Saturday afternoon. Colin continues to pass through an unfavorable environment for development--an upper-level low pressure system with dry air and high wind shear. High wind shear of 20 - 25 knots has exposed the surface circulation to view, as seen in recent satellite imagery. Colin's heavy thunderstorm activity is all on the east side of the storm, and the associated rains can now be seen approaching the island on Bermuda radar.

Forecast for Colin
The latest SHIPS model forecast predicts that wind shear will drop to the low to moderate range, 5 - 15 knots, tonight through Saturday afternoon. This relaxation of shear prompts the intensity models to predict that Colin will strengthen to a 50 - 70 mph tropical storm by Sunday. With the forecast path of the storm predicted to take Colin just west of Bermuda, the island will be in the strong right front quadrant of the storm, and may see wind gusts in excess of hurricane force, 74 mph. After its encounter with Bermuda, Colin will head towards Newfoundland, and it is possible the storm could bring tropical storm force winds to the island on Monday. However, wind shear will be on the increase again beginning Saturday night, and it is unlikely Colin will be a hurricane when it makes it closest approach to Newfoundland.


Figure 1. Morning satellite image of Colin.

93L
A tropical wave (Invest 93) about 700 miles west of the Cape Verdes Islands off the coast of Africa is moving northwest at 10 mph. Wind shear is a moderate 10 - 20 knots over 93L, which is low enough to allow some slow development. This system currently does not appear to be a concern to any land areas over the next seven days. NHC is giving a 40% chance of this disturbance developing into a tropical depression by Sunday morning. The GFS and NOGAPS models predict 93L will become a tropical depression.


Figure 2. Smoke from fires in Russia on August 4 covers an area over 3,000 km (1860 miles) across. If the smoke were in the United States, it would extend approximately from San Francisco to Chicago. Visibility in Moscow dropped to 20 meters (0.01 miles) on August 4, and health officials warned that everyone, including healthy people, needed to take preventative measures such as staying indoors or wearing a mask outdoors. Image credit: NASA.

The Great Russian Heat Wave of 2010 continues
One of the most remarkable weather events of my lifetime is unfolding this summer in Russia, where an unprecedented heat wave has brought another day of 102°F heat to the nation's capital. At 3:30 pm local time today, the mercury hit 39°C (102.2°F) at Moscow's Domodedovo Airport. Moscow had never recorded a temperature exceeding 100°F prior to this year, and today marks the second time the city has beaten the 100°F mark. The first time was on July 29, when the Moscow observatory recorded 100.8°C and Baltschug, another official downtown Moscow weather site, hit an astonishing 102.2°F (39.0°C). Prior to this year, the hottest temperature in Moscow's history was 37.2°C (99°F), set in August 1920. The Moscow Observatory has now matched or exceeded this 1920 all-time record five times in the past eleven days, including today. The 2010 average July temperature in Moscow was 7.8°C (14°F) above normal, smashing the previous record for hottest July, set in 1938 (5.3°C above normal.) July 2010 also set the record for most July days in excess of 30°C--twenty-two. The previous record was 13 such days, set in July 1972. The past 24 days in a row have exceeded 30°C in Moscow, and there is no relief in sight--the latest forecast for Moscow calls for high temperatures near 100°F (37.8°C) for the next seven days. It is stunning to me that the country whose famous winters stopped the armies of Napoleon and Hitler is experiencing day after day of heat near 100°F, with no end in sight.

Thousands of deaths, severe fires, and the threat of radioactive contamination
The extreme heat has led to thousands of premature deaths in Russia. According to Yevgenia Smirnova, an official from the Moscow registry office, "We recorded 14,340 deaths in Moscow in July, that is 4,824 deaths more than in July, 2009." Undoubtedly thousands of additional premature deaths have occurred in the rest of Russia as a result of the heat. The heat has also caused the worst drought conditions in European Russia in a half-century, prompting the Russian government to suspend wheat exports. The drought has caused extreme fire danger over most of European Russia (Figure 3), and fires in Russia have killed at least 50 people in the past week and leveled thousands of homes. The fires are the worst since 1972, when massive forest and peat bog fires burned an area of 100,000 square km and killed at 104 people in the Moscow region alone. Smoke from the current fires spans a region over 3,000 km (1,860 miles) from east to west, approximately the distance from San Francisco to Chicago. Dozens of flights were canceled at Moscow's airports today, thanks to visibilities of 300 meters in smoke. Also of concern is fires that have hit the Bryansk region of western Russia, which suffered radioactive contamination from the Chernobyl nuclear disaster in nearby Ukraine. There are fears that fires may burn through the contaminated area, releasing harmful radiation into the atmosphere.


Figure 3. Fire danger in Russia for August 5, 2010. Extreme fire danger (Category 5, red colors) was seen over much of the European portion of Russia. Image credit: Hydrometcentre, Russia.

Why has Russia's heat wave been so long and intense?
Dr. Rob Carver has done a detailed analysis of the remarkable Russian heat wave in his latest post, The Great Russian Heat Wave of July 2010. A persistent jet stream pattern has set up over Europe, thanks to a phenomena known as blocking. A ridge of high pressure has remained anchored over Russia, and the hot and dry conditions have created helped intensify this ridge in a positive feedback loop. As a result, soil moisture in some portions of European Russia has dropped to levels one would expect only once every 500 years.

Next update
I'll have an update on Saturday morning.

Jeff Masters

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Quoting MiamiHurricanes09:
Good evening everyone!
in unison and harmony, all logged in bloggers respond, "Good evening Mr. MiamiHurricanes09"
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Quoting MiamiHurricanes09:
Good evening everyone!



hi 09


any thing new about 92 and 93L?
Member Since: May 21, 2006 Posts: 5089 Comments: 114049
Good evening everyone!
Member Since: September 2, 2009 Posts: 130 Comments: 21032
deleted
Member Since: October 25, 2005 Posts: 19 Comments: 20686
The GFS is showing favorable conditions continuing to develop, mjo wise.

The CFS looks good too.
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nothing like old, freezerburnt, fried shrimp...might as well just leave the shells on and veins in, would never know the difference.
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93L looks good
Member Since: May 21, 2006 Posts: 5089 Comments: 114049
Wow. U can tell a lot of pple in here don't take too many photos and post them in this blog..... lol

KanKun, re: 1009.... it's not that they don't WANT to help u out.... lol

Try uploading ur photo to wunderground. Then use the method[s] mentioned to post the pic to the blog. It's really easy, and approval takes a couple minutes...

Member Since: October 25, 2005 Posts: 19 Comments: 20686
Quoting barbamz:


Here you go
http://wiki.wunderground.com/index.php/WunderBlogs_-_Adding_images


Thanks!!!!!
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Quoting Snowlover123:


In your opinion, how "good" do you think the NOGAPS model does at forecasting? I like the NOGAPS and trust the NOGAPS model. Pretty good, IMHO.
bad thing about the NOGAPS is that it is initialized with a synthetic/fake/made up vortex as to position and strength. And since proper initialization is key to the models, in a case where there is no formed system, as 93L, I'm not sure how much credibility I would give it. It has the capability of forecasting pretty decent tracks but junk as far as intensity. It has had its good days but its also had its bad days.
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I removed it.
I believe the Belize radar loop (long range) is showing the center of 92L at 17N lat.
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Quoting snotly:
What's up with the NW Caribbean? Any pressure readings falling under all that convection?
Conditions at 42057 as of
(5:50 pm EDT)
2150 GMT on 08/06/2010:
Unit of Measure: Time Zone:

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Direction Wind Direction (WDIR): N ( 360 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 7.8 kts
5-day plot - Wind Gust Wind Gust (GST): 9.7 kts
5-day plot - Wave Height Wave Height (WVHT): 3.3 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 7 sec
5-day plot - Average Period Average Period (APD): 5.0 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.86 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.03 in ( Falling )

5-day plot - Air Temperature Air Temperature (ATMP): 82.0 °F
5-day plot - Water Temperature Water Temperature (WTMP): 84.4 °F
5-day plot - Dew Point Dew Point (DEWP): 77.7 °F
5-day plot - Heat Index Heat Index (HEAT): 90.7 °F
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As far as the highs and troughs go StormW has a good blog about that today.

On Houston in particular this is a discussion from their NWS office. It's not a long term outlook but you can usually get their opinions a few days out. Link

ANOTHER DAY OF PLUS-105F HEAT INDEXES WITHIN THIS ANALOG PATTERN
HAS THE HEAT ADVISORY EXTENDED OUT THROUGH SATURDAY. CHANCES OF A
CONTINUANCE APPEAR VERY HIGH THROUGH AT LEAST MID TO LATE NEXT WEEK.
RIDGING RE-ASSERTS ITSELF FURTHER SOUTH EARLY NEXT WEEK WITH A
POSSIBLE WEAK EASTERLY WAVE/REFLECTION OF TUTT TO NEAR TEXAS COAST
BY THURSDAY. THE OTHER MORE WET SCENARIO IS THAT OF FALLING INTO A
WEAKNESS CHANNEL BETWEEN TWO EAST-WEST RIDGES...A STRETCH YES...BUT
HOPE IS STILL ALIVE OF RECEIVING MORE WIDESPREAD RAIN THIS MONTH.
31

&&

.MARINE...
WEAK HIGH PRESSURE OVER THE UPPER TX COAST WILL BREAK DOWN ALLOWING
FOR A MORE PRONOUNCED ONSHORE FLOW THROUGH THE WEEKEND. WINDS WILL
GENERALLY BE AROUND 10 KNOTS FROM THE SW/S BUT MAY BECOME MORE SE
EARLY NEXT WEEK. NOCTURNAL INCREASES IN WINDS MAY PUSH SEAS IN
OFFSHORE AREAS TO 3 FEET SATURDAY NIGHT AND SUNDAY NIGHT. OTHERWISE
SEAS WILL REMAIN AROUND 2 FEET THROUGH THE REST OF THE WEEK.


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93L will be going up too 60% too 70% at the next two i can feel it
Member Since: May 21, 2006 Posts: 5089 Comments: 114049
Quoting stormhank:
anyone have an updated MJO octant map...the site I have hasnt updated since Aug. 3rd..must be having problems with the site???


Here:
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Quoting earthlydragonfly:



Just kidding Baha!!! Afternoon everyone!!!
Hey dude! Any decent lightning photos lately? LOL

Member Since: October 25, 2005 Posts: 19 Comments: 20686
Quoting Sfloridacat5:
Can someone bring up this radar loop for me?

Its from Belize. Its starting to show 92L.

http://www.hydromet.gov.bz/Radar%20Loop%20250km.htm



plzs re move that link am geting a pop up window from it



Member Since: May 21, 2006 Posts: 5089 Comments: 114049
Quoting CybrTeddy:




I can't see it. Maybe its just my computer.
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Quoting WindynEYW:
BERMUDA IN THE LINE OF FIRE FOR COLIN


Colin ait nothing. I kinda like the tropical storms. Its sort of exciting. Notice I said Tropical storms not the Hurricanes. We get our share of both her in Fl.
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Quoting wfyweather:
Why is everyone throwing a fit about 92L when we have an active tropical storm... and another invest with more potential out there? I just don't get it... 92L probably won't develop.

wfyweather...first rule...anything that has the potential to develop tropically is always worth looking at and watching. Look at what Humberto did. These things can spin up overnight. All three deserve attention. 92L has really surprised me today, I thought it was done and gone. Just goes to show, I did not even follow my own advice I am giving you! See! lol. It may or may not develop but do not count it out.
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Quoting WindynEYW:
BERMUDA IN THE LINE OF FIRE FOR COLIN


Amazing how tiny Bermuda looks on that map. Stay safe everyone....
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Quoting Sfloridacat5:
Can someone bring up this radar loop for me?

Its from Belize. Its starting to show 92L.

http://www.hydromet.gov.bz/Radar%20Loop%20250km.htm


Member Since: July 8, 2005 Posts: 259 Comments: 23012
Quoting 954FtLCane:

well it'll just take you a little longer to get there then... lol... bar closes at 2 so if you start now.....hmmmm..... make sure to tell everyone something will be brewing in the Bahamas.....
In the Bahamas, it's usually Kalik beer....

Quoting KanKunKid:
Well, I'll probably get booted for this but since I'm apparently on everyone's ignore list:

I just asked a simple question and nobody wants to answer it or direct me to where to find the information. You all are watching 92L from a satellite, I'm watching it out my window, right outside. I was thinking you all would appreciate a picture of what I see, but apparently if it doesn't come from a satellite you don't wanna see it. I guess I don't fit into your "clique" so, in the immortal words of Eric Cartman: "Screw you guys, I'm going home"!
Geez, dude, I was just eating dinner, sorry I just saw your post a few minutes ago.... I have a feeling some pple didn't really understand what u were trying to say....

Member Since: October 25, 2005 Posts: 19 Comments: 20686
BERMUDA IN THE LINE OF FIRE FOR COLIN
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Quoting hunkerdown:
there are better models for better circumstances. Some are better at long range, some better at short range, some poor at intensity and some poor at cyclogenises. Notice I didn't say any were "good" at intensity or cyclogenises cause I don't put much credence in models for cyclogenesis and intensity may be even harder to predict.


In your opinion, how "good" do you think the NOGAPS model does at forecasting? I like the NOGAPS and trust the NOGAPS model. Pretty good, IMHO.
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Quoting severstorm:

Afternoon to all, where are you located in fl.



Northern Pinellas county
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Welcome Tx Novice!
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Can someone bring up this radar loop for me?

Its from Belize. Its starting to show 92L.

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Quoting snotly:
What's up with the NW Caribbean? Any pressure readings falling under all that convection?


Last time I checked, no. It has decent convection, but now it needs to generate an organized center. In the later frames of an animated loop of the system, you can see more cyclonic turning being observed, indicating that this is getting better organized.
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Thanx for that! I never even tried until I saw your instructions. Cake and Pie!
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Quoting Snowlover123:


IMHO, the NOGAPS is a fairly decent model, although some of the other models packed into that consensus to the NW are pretty good as well. There isn't really any better one, although that used to be the case, and partially still is, with the ECMWF and the GFS models.
there are better models for better circumstances. Some are better at long range, some better at short range, some poor at intensity and some poor at cyclogenises. Notice I didn't say any were "good" at intensity or cyclogenises cause I don't put much credence in models for cyclogenesis and intensity may be even harder to predict.
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Quoting KanKunKid:
How do you get a picture posted here that you just took of a relevant weather event?

Do they all go through the approval mill first?

Or can you post it on the internet somewhere else and link to it?
Or just draw pictures and describe them as best you can?
Go to the top of the page, find "My Quick Menu" and click on my photos. Wunderground will allow u to upload any of your personal photos. Then u can post that photo to the blog using the usual photo posting methods.

Member Since: October 25, 2005 Posts: 19 Comments: 20686
1022. snotly
What's up with the NW Caribbean? Any pressure readings falling under all that convection?
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1016, thank you too
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92l looks great right now, but I wonder if it's going to fizzle again overnight? I still haven't figured out why systems have been doing that [fizzling at night, blowing up in the daytime] so far this season....
Member Since: October 25, 2005 Posts: 19 Comments: 20686
SammyWammyBammy, those satellite images of 92L and 93L you've presented look very nice. 92L and 93L could become tropical systems in the next couple of days.
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PtwnBryan: thank you.
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Updated 2010 Atlantic Hurricane Season Outlook: Summary

NOAA’s updated 2010 Atlantic Hurricane Season Outlook calls for a 90% chance of an above normal season. There is only a 10% chance of a near-normal season, and no expectation the season will be below normal. Therefore, 2010 is expected to become the eleventh above-normal season since 1995. See NOAA definitions of above-, near-, and below-normal seasons. The Atlantic hurricane region (or basin) includes the North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico.

The atmospheric and oceanic conditions now in place over the tropical Atlantic Ocean and Caribbean Sea are very conducive to hurricane formation, as was predicted in NOAA’s pre-season outlook issued in May. These conditions are expected to persist throughout the peak months (August-October) of the Atlantic hurricane season, in association with three climate factors; the tropical multi-decadal signal, La Niña, and very warm temperatures in the tropical Atlantic Ocean and Caribbean Sea. In addition, dynamical model forecasts tropical cyclone activity continue to predict a very active season.

We estimate a 70% probability for each of the following seasonal (June-November) ranges of activity during 2010. These ranges are consistent with NOAA’s May outlook, and reiterate a high likelihood of a very active season (i.e. hyperactive, defined by ACE ? 175% of median), perhaps one of the more active on record.

14-20 Named Storms,
8-12 Hurricanes
4-6 Major Hurricanes
An ACE range of 170%-260% of the median.

The activity is expected to fall within these ranges in about 70% of seasons with similar climate conditions and uncertainties to those expected this year. They do not represent the total possible ranges of activity seen in past similar years.

These ranges include the two tropical storms and one hurricane seen to date. During June – July 2010, two named storms (Hurricane Alex and Tropical Storm Bonnie) formed in the Atlantic basin. The pre-season outlook issued in late May reflected the possibility of even more early-season activity. As a result, the upper ends of the predicted ranges have been reduced.

Nonetheless, significant activity is predicted for the remainder of the season, with an additional 12-17 named storms, of which 7-11 are expected to become hurricanes with 4-6 reaching major hurricane status.

Any region or community can experience a devastating hurricane regardless of the overall seasonal activity. However, during hyperactive seasons, the historical probability for multiple U.S. hurricane strikes, and for multiple hurricane strikes in the region around the Caribbean Sea, increases sharply. Therefore, it is even more imperative for this season that residents and government officials in hurricane-vulnerable communities have an effective hurricane preparedness plan in place.

NOAA does not make an official seasonal landfall outlook. Predicting where and when hurricanes will strike is related to daily weather patterns, which are not predictable weeks or months in advance. Therefore, it is currently not possible to reliably predict the number or intensity of landfalling hurricanes at these extended ranges, or whether a specific locality will be impacted by a hurricane this season.

DISCUSSION

1. Expected 2010 activity

Current oceanic and atmospheric conditions, known climate factors, and dynamical model forecasts, all point to an above normal Atlantic hurricane season during 2010. NOAA’s updated seasonal outlook calls for a 90% chance of an above-normal season, and a 10% chance of a near-normal season. This updated outlook is consistent with NOAA’s pre-season outlook issued in May, which indicated an 85% chance of an above normal season.

An important measure of the total seasonal activity is NOAA’s Accumulated Cyclone Energy (ACE) index, which accounts for the combined intensity and duration of all named storms and hurricanes during the season. According to NOAA’s hurricane season classifications, an ACE value at or above 175% of the median reflects a very active (or hyperactive) season. For 2010, we estimate a 70% chance that the seasonal ACE range will be 170%-260% of the median. This range indicates a high likelihood of a hyperactive season.

The 2010 Atlantic hurricane season is expected (with 70% chance) to produce a total of 14-20 named storms, of which 8-12 are expected to become hurricanes with 4-6 becoming major hurricanes. If the activity reaches the upper end of our predicted ranges, the season will be one of the more active on record.

These ranges include the two tropical storms and one hurricane seen to date. During June – July 2010, two named storms (Hurricane Alex and Tropical Storm Bonnie) formed in the Atlantic basin. The pre-season outlook issued in late May reflected the possibility of even more early-season activity. As a result, the upper ends of the predicted ranges have been reduced.

Nonetheless, significant activity is predicted for the remainder of the season, with an additional 12-17 named storms, of which 7-11 are expected to become hurricanes with 4-6 reaching major hurricane status.

Because of the high threat of a very active season, we are including some historical U.S. hurricane landfall statistics based on past similar seasons. These statistics do not represent an explicit hurricane landfall forecast, as it is not currently possible to reliably predict such activity so far in advance.

Very active seasons feature more hurricanes and major hurricanes, as well as systematic changes in where these systems develop and track. In particular, they feature significantly increased tropical cyclone activity in the Main Development Region (MDR, which includes the Caribbean Sea and tropical Atlantic Ocean between 9°N-21.5°N; Goldenberg et al. 2001). Such storms typically have more time to strengthen, and often track farther westward than their counterparts that develop to the north. As a result, there is a systematic increase in tropical cyclone activity in the western portion of the Atlantic basin, which results in an increased threat to the continental U.S., the Gulf of Mexico, and the region around the Caribbean Sea.

The historical probabilities for multiple hurricane strikes increase markedly during very active seasons for both the Gulf Coast and Atlantic Coast of the United States. The region around the Caribbean Sea also sees a sharp increase in hurricane activity during these seasons.

Historically, all above normal seasons have produced at least one named storm in the Gulf of Mexico, and 95% have produced at least two named storms in the Gulf. Most of this activity (80%) occurs during August-October, with seventy percent of above normal seasons seeing at least three named storms in the Gulf of Mexico during this period.

While the climate patterns are indicating an increased threat of hurricane landfalls this year, predicting the location, number, timing, and strength, of those events is ultimately related to the daily weather patterns, which are not predictable weeks or months in advance. As a result, it is currently not possible to reliably predict the number or intensity of landfalling hurricanes at these extended ranges, or whether a given locality will be impacted by a hurricane this season. Therefore, NOAA does not make an official seasonal hurricane landfall outlook.

2. Science behind the updated 2010 Outlook

The updated 2010 Atlantic hurricane season outlook primarily reflects a set of atmospheric and oceanic conditions now in place, which are very conducive to hurricane formation. These conditions are expected to persist through the peak months of the Atlantic hurricane season, and are linked to three climate factors: 1) the tropical multi-decadal signal, 2) La Niña, and 3) a continuation of exceptionally warm sea surface temperatures (SSTs) in the Main Development Region. These conditions are consistent with NOAA’s pre-season outlook issued in May.

This outlook also takes into account dynamical model predictions from new models such as the NOAA Climate Forecast System (CFS), the European Centre for Medium Range Weather Forecasting (ECMWF), the United Kingdom Meteorology (UKMET) office model, and the EUROpean Seasonal to Inter-annual Prediction (EUROSIP) ensemble. All of these models continue to predict a high likelihood of a very active season.

a. Expected continuation of tropical multi-decadal signal
One factor guiding this outlook is the continuation of the tropical multi-decadal signal, which has contributed to the high-activity era in the Atlantic basin that began in 1995. Key components of this signal include an enhanced west African monsoon circulation and above average SSTs in both the lower and higher latitudes of the North Atlantic Ocean.

Within the MDR, atmospheric aspects of the tropical multi-decadal signal seen since 1995 include reduced vertical wind shear, weaker easterly trade winds, and an extensive area of cyclonic shear at 700-hPa along the equatorward flank of the African Easterly Jet. These conditions are now in place, along with other related circulation features in the upper atmosphere that are also conducive to hurricane formation, including 1) an extensive area of anomalous easterly winds extending westward from Africa and 2) anticyclonic circulation (i.e. streamfunction) anomalies in the upper atmosphere over subtropical Atlantic in both hemispheres.

b. La Niña
Another climate factor known to impact Atlantic hurricane activity is the El Niño/ Southern Oscillation (ENSO). The three phases of ENSO are El Niño, La Niña, and Neutral. La Niña refers to a periodic anomalous cooling of SSTs in the central and eastern equatorial Pacific Ocean. This cooling affects rainfall patterns across the tropical Pacific which, in turn, alters wind patterns so as to reduce the vertical wind shear in the MDR. Consequently, La Niña is typically more conducive to increased Atlantic hurricane activity (Gray 1984).

La Niña developed during July, according to the latest ENSO Diagnostic Discussion issued by NOAA’s Climate Prediction Center. Nearly all ENSO forecast models now predict La Niña to continue through the Atlantic hurricane season.

The upper-level atmospheric circulation is now in a La Niña state, as indicated by cyclonic streamfunction anomalies in the central subtropical Pacific of both hemispheres (blue shading in NH, red shading in SH). Over the eastern subtropical Pacific and Atlantic basins in both hemispheres, the upper-level circulation is also consistent with La Niña, as indicated by extensive easterly wind anomalies and anticyclonic streamfunction anomalies (Red in NH, blue in SH).

Over the Atlantic basin, these conditions act to extend westward and accentuate the circulation anomalies associated with the tropical multi-decadal signal. This combination accounts for the basin-wide patterns of upper-level easterly wind anomalies and reduced vertical wind shear now present across the MDR, and greatly increases the probability of a very active Atlantic hurricane season during 2010.

c. Above average SSTs in the Main Development Region
Another factor guiding the outlook is the expectation of much above-average to near-record SSTs in the MDR during August-October. This prediction is based on climate model forecasts such as NOAA’s Climate Forecast System (CFS). and on observations over the last several months. Since March, monthly SST departures averaged over the entire MDR have been at record levels. The most recent SST analysis indicates departures exceeding +1.0oC across most of the region. This warmth is much larger than anywhere else in the global tropics, and is a further indication that climate conditions are conducive for hurricane development in the Atlantic basin.

3. Further analysis of the Ongoing High Activity Era in the Atlantic Basin

Atlantic hurricane seasons exhibit extended periods lasting decades of generally above-normal or below-normal activity. These fluctuations in hurricane activity result almost entirely from differences in the number of hurricanes and major hurricanes forming from tropical storms first named in the MDR.

The current high-activity era has been in place since 1995. Hurricane seasons during 1995-2009 have averaged about 14.5 named storms, 8 hurricanes, and 4 major hurricanes, with an average ACE index of 160% of the median. NOAA classifies ten of the fifteen seasons since 1995 as above normal, with seven being hyperactive (ACE > 175% of median). Only five seasons since 1995 have not been above normal, which include four El Niño years (1997, 2002, 2006, and 2009) and the 2007 season.

This high level of activity since 1995 contrasts sharply to the low-activity era of 1971-1994 (Goldenberg et al. 2001), which averaged only 8.5 named storms, 5 hurricanes, and 1.5 major hurricanes, and had an average ACE index of only 75% of the median. One-half of the seasons during this low-activity era were below normal, only three were above normal (1980, 1988, 1989), and none were hyperactive.

Within the MDR, the atmospheric circulation anomalies that contribute to these long-period fluctuations in hurricane activity are strongly linked to the tropical multi-decadal signal (Bell and Chelliah 2006). A change in the phase of the multi-decadal signal coincides with the transition in 1995 from a low-activity era to the current high-activity era.
Member Since: May 21, 2006 Posts: 5089 Comments: 114049
Hooly crap, no wonder i cant think, I forgot my 4:00 o clock meds. be back
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Quoting will45:


its the xtrap. that shows the xtrapolitated direction that the system is actually moving
nope, its the NOGAPS
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957. AustinTXWeather 10:15 PM GMT on August 06, 2010
Quoting PtownBryan:


92L is def looking better. Came back from the dead just like Colin! I think the high over us here in Houston will continue to be strong enough to keep anything that develops away from us. But that just means more heat advisories =(


This sparked a question from me -- how long do highs tend to linger over an area.. do they vary or is there a general pattern? I know there is prob a lot of factors involved so I'm wondering more generally -- For example, if a TS was entered into the Gulf this weekend and was heading towards Texas where there is a high, can you anticipate the high would still be there by the time it was a threat (ie.. say 4-5 days out)?
Action: Quote | Ignore User


Hey Austin...highs differ in strength and lenghts of time they are where they are. I think the only consistent High is the Bermuda high...and someone correct me if I am wrong. I said what i said earlier because I was just going by what one of our local met's here in Houston had on his forecast...lots of hot, dry, high pressure influenced days ahead. Highs are tricky, but you can forecast if they will be there or not. It is obviously hard to forecast completely correctly because sometimes they are not as strong or weak as expected. Hurricane Rita is a fine example of this! I bet Austin is baking right now! lol
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.