Atlantic hurricane outlook for the remainder of June

By: Dr. Jeff Masters , 2:32 PM GMT on June 12, 2009

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The last half of June is usually one of the quietest portions of hurricane season. In the 14 years since the current active hurricane period began in 1995, only four tropical storms formed in the last half of June. Thus, recent history gives us a 29% chance of a last-half-of-June named storm. None of those four storms since 1995 became a hurricane, and hurricanes are quite rare in June.

Sea Surface Temperatures
Sea Surface Temperatures (SSTs) have remained close to average over the tropical Atlantic between Africa and Central America this month (Figure 1). These are the are the coolest SST anomalies we've seen since 1994. The strength of the Azores-Bermuda high has been near average over the past two weeks, driving near-average trade winds. Stronger-than-average trade winds were observed through most of the period November 2008 - May 2009, which helped cool the tropical Atlantic substantially. Strong winds mix up colder water from the depths and cause greater evaporative cooling. The latest 2-week run of the GFS model predicts continued average trade winds over the tropical Atlantic for the remainder of June, so expect the near-average SSTs to continue over the tropical Atlantic as we head into July.

Typically, June tropical storms form over the Gulf of Mexico, Western Caribbean, and Gulf Stream waters just offshore Florida, where water temperatures are warmest. SSTs are 26 - 28°C in these regions, which is about 0.5°C above average for this time of year. June storms typically form when a cold front moves off the U.S. coast and stalls out, with the old frontal boundary serving as a focal point for development of a tropical disturbance. African tropical waves, which serve as the instigators of about 85% of all major hurricanes, are usually too far south in June to trigger tropical storm formation. SSTs are too cold in June to allow storms to develop between the coast of Africa and the Lesser Antilles Islands--there has only been once such development in the historical record--Ana of 1979, which coincidentally will be the name given to this year's first storm.


Figure 1. Sea Surface Temperature (SST) departure from average for June 11, 2009. SSTs were near average over the tropical Atlantic. Note the large region of above average SSTs along the Equatorial Pacific off the coast of South America, signaling the possible start of an El Niño episode. Image credit: NOAA/NESDIS

El Niño
NOAA's Climate Prediction Center issued an El Niño Watch last week, saying "that conditions are favorable for a transition from neutral to El Niño conditions during June - August 2009". The pattern of changes in surface winds, upper-level winds, sea surface temperatures, and deeper water heat content are all consistent with what has been observed during previous developing El Niños. We are currently experiencing neutral conditions, with ocean temperatures in the Equatorial Eastern Pacific just 0.2°C below the threshold for El Niño. In the week since the El Niño watch was issued, ocean temperatures have remained nearly steady in the Eastern Pacific, so we are not rushing into an El Niño just yet. As I discussed in detail in an earlier post, most of our more advanced El Niño computer models are predicting a weak El Niño event for the coming Atlantic hurricane season. If this indeed occurs, it is likely that Atlantic hurricane activity will be suppressed due to the strong upper-level winds an El Niño usually brings to the tropical Atlantic, creating high wind shear that tears hurricanes apart.

Wind shear
Wind shear is usually defined as the difference in wind between 200 mb (roughly 40,000 foot altitude) and 850 mb (roughly 5,000 foot altitude). In most circumstances, wind shear above 20 knots will act to inhibit tropical storm formation. Wind shear below 12 knots is very conducive for tropical storm formation. High wind shear acts to tear a storm apart. The jet stream's band of strong high-altitude winds is the main source of wind shear in June over the Atlantic hurricane breeding grounds, since the jet is very active and located quite far south this time of year.

The jet stream over the past few weeks has been locked into a pattern where a southern branch (the subtropical jet stream) brings high wind shear over the Caribbean, and a northern branch (the polar jet stream) brings high wind shear offshore of New England. This often leaves a "hole" of low shear between the two branches off the coast of North Carolina, which is where Tropical Depression One formed at the end of May.

The jet stream is forecast (Figure 2) to maintain this two-branch pattern over the coming two weeks. This means that the waters offshore of the Carolinas are the most likely place for a tropical storm to form during this period.


Figure 2. Wind shear in m/s between 200 mb and 850 mb, as forecast by the 00Z June 12, 2009 run of the GFS model. The position of the subtropical jet stream is forecast to change little over the next two weeks, and this jet will bring high wind shear to the Caribbean and Gulf of Mexico for most of the remainder of June. There will at times be a region of low shear between the polar jet (northern set of arrows on the plots) and the subtropical jet, allowing for possible tropical development off the coast of North Carolina. Wind speeds are given in m/s; multiply by two to get a rough conversion to knots. Thus, the red regions of low shear range from 0 - 16 knots.

Steering currents
The steering current pattern over the past few weeks has not changed much, and is typical for June. We have an active jet stream bringing many troughs of low pressure off the East Coast of the U.S. These troughs are frequent enough and strong enough to recurve any tropical storms or hurricanes that might penetrate north of the Caribbean Sea. Steering current patterns are predictable only about 3 - 5 days in the future, although we can make very general forecasts about the pattern as much as two weeks in advance. At present, it appears that the coming two weeks will maintain the typical June pattern, bringing many troughs of low pressure off the East Coast capable of recurving any June storms that might form. There is no telling what might happen during the peak months of August, September, and October--we might be in for a repeat of the favorable 2006 steering current pattern that recurved every storm out to sea--or the unfavorable 2008 pattern, that steered Ike and Gustav into the Gulf of Mexico.

Summary
Recent history suggests a 29% chance of a named storm occurring in the second half of June. Given that the current SST pattern and two-week wind shear forecast look fairly typical for June, I'll go with a 20% chance of a named storm forming during the last half of June. There's currently nothing out there of note, but we should start watching the region off the North Carolina coast 4 - 7 days from now.

Other stuff
Saturday, June 13 marks the last day of the Vortex2 tornado research project. The team of University of Michigan students writing our Vortex2 blog has posted some great photos and accounts of the storms they caught up to this week.

The Portlight.org charity is hard at work helping victims of the Volusia County, Florida floods.

Today's post will likely be my final "live" post until June 29, as I am headed to London, England, and Kefalonia Island, Greece for my first-ever European vacation. My fellow wunderground meteorologists will be posting to my blog if any tropical weather of note develops. I also recommend following the blog of wunderblogger Weather456, who works as a forecaster on St. Kitts Island in the Lesser Antilles. If the tropics remain quiet, I've prepared some "canned" blogs that will be posted on my blog. The topics include:

--The Atlantic Meridional Mode: implications for the 2009 hurricane season
--African dust forecast for the 2009 Atlantic hurricane season
--U.S. vulnerability to sea level rise: the Coastal Vulnerability Index (CVI)
--The six Hurricane and Typhoon Hunter flights that never came back
--Sea level rise: the forecast
--Sea level rise in the Northeast U.S. from ocean current changes

Jeff Masters

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2743. singlehander
4:28 PM GMT on June 23, 2009
I live on the west coast of Mexico, in Mazatlan.
There is always a lot of information on Atlantic hurricanes, but not much on eastern Pacific storms. This year we have had a tropical storm and the first hurricane [Andres] has formed south of Puerta Vallarta. The TS arrived 10 hours ahead of the Wonderweather pridictions, with gusts of 75 MPH.
I understand that these Pacific storms don't impact the US significantly, but a little more info on our weather would be appreciated. Is there a prediction of hurricanes for the Pacific for the coming season?
Member Since: February 11, 2008 Posts: 7 Comments: 11
2742. swatkins
10:22 PM GMT on June 16, 2009
So like maybe we should turn this loop over to the National Enquire, as positive proof ET is visiting us, then use the money for a big party :)
2741. Stormchaser2007
10:20 PM GMT on June 16, 2009
New blog
Member Since: June 9, 2007 Posts: 4 Comments: 15788
2739. RitaEvac
10:17 PM GMT on June 16, 2009
Lets get Gator to do a report on this, it might be some new phenomenon!
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2738. Stormchaser2007
10:16 PM GMT on June 16, 2009
Quoting swatkins:
Well it looks like fast is relative. The flash took from 15:45 to 21:45 to move over that area :)


Ive seen it hundreds of times. Its definitely the sun.
Member Since: June 9, 2007 Posts: 4 Comments: 15788
2737. RitaEvac
10:15 PM GMT on June 16, 2009
Quoting hurricane2009:


That is the sun glint, which is the sun reflecting off the satellite and it gets captured in the pic.


its the sun reflecting off the ocean of the earth moving west which is the world turning making it move
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2736. Stormchaser2007
10:13 PM GMT on June 16, 2009
Quoting swatkins:
Please take a look at this loop.

At 15:15 UT time a bright flash starts just south of the ABC islands and moves very fast to the west and up the western coast of Mexico.. As the frames move through the loop you can see it become very bright then start to fade away.

What the heck is it and how do you save a copy of the loop?


We call that the "Sun"
Member Since: June 9, 2007 Posts: 4 Comments: 15788
2735. swatkins
10:13 PM GMT on June 16, 2009
Well it looks like fast is relative. The flash took from 15:45 to 21:45 to move over that area :)
2733. extreme236
10:12 PM GMT on June 16, 2009
Quoting RitaEvac:


I listened to the media then, and now its edged into my memory for life


I'd rather be safe than sorry. Maybe you don't feel that way.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2732. RitaEvac
10:09 PM GMT on June 16, 2009
Quoting gator23:


Pretty bold for someone whos Avatar reads "RitaEvac"


I listened to the media then, and now its edged into my memory for life
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2731. swatkins
10:07 PM GMT on June 16, 2009
Please take a look at this loop.

At 15:15 UT time a bright flash starts just south of the ABC islands and moves very fast to the west and up the western coast of Mexico.. As the frames move through the loop you can see it become very bright then start to fade away.

What the heck is it and how do you save a copy of the loop?
2730. RitaEvac
10:06 PM GMT on June 16, 2009
Quoting hurricane2009:


What are you a prophet now?

lol


LMAO
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2728. Orcasystems
10:05 PM GMT on June 16, 2009
Quoting gator23:


Pretty bold for someone whos Avatar reads "RitaEvac"


I found that if you click on those little blue letters.. you know the ones right beside the word "quote" its nick doesn't show up so much :)
Member Since: October 1, 2007 Posts: 81 Comments: 26511
2727. Cavin Rawlins
10:04 PM GMT on June 16, 2009
Quoting hurricane2009:
Its going 456

sorry to hear about your crash, must be the medias' fault lmao


lol power lost and my ups was not working at the time.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2726. gator23
10:04 PM GMT on June 16, 2009
Quoting RitaEvac:
We all live and die Gator, no need to be afraid.


Pretty bold for someone whos Avatar reads "RitaEvac"
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2724. RitaEvac
10:03 PM GMT on June 16, 2009
We all live and die Gator, no need to be afraid.
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2721. gator23
10:01 PM GMT on June 16, 2009
Quoting RitaEvac:


lol local news is good, not global


Ahh I see. Iraq is beautiful this time of year and since there is no World news I guess is a great place for me to go visit right now.
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2720. Cavin Rawlins
10:01 PM GMT on June 16, 2009
Hey Good Afternoon

Computer severly crash today and lost all my files but I had some back-up. I also lost A tropical cyclone report on 90L, TD 1 and 92L I was working on. I will still provide my updates though.

Hey Jp, welcome back, hows it going?
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2719. Orcasystems
10:01 PM GMT on June 16, 2009
Quoting RitaEvac:


lol local news is good, not global


I give up... your making a stick look pretty smart.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
2717. RitaEvac
9:59 PM GMT on June 16, 2009
Quoting gator23:


1. I work in Media
2. I studied media at length
3. I promise you we dont care to create a conspiracy.

That said, There are no old dayss Media has been around since the Roman times.
But thats ok you dont need media. So the next time a terrorist attack happens you wont know. Or after a hurricane if your water is unsafe to drink you wont know. Or if your driving to work and the expressway is jammed you wont know...


lol local news is good, not global
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2715. extreme236
9:58 PM GMT on June 16, 2009
Quoting RitaEvac:
There's always cat 5s heading for my area, they just weaken before landfall, or go the friggin other way, no need for hype by the media.


Yes, keeping people uninformed about any possible threat is definatly the way to go. Cause its not always gonna be that way. You've just gotten lucky.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2713. gator23
9:56 PM GMT on June 16, 2009
Quoting RitaEvac:
There's always cat 5s heading for my area, they just weaken before landfall, or go the friggin other way, no need for hype by the media.

We in Miami had a similar attitude then oops Andrew... Im done dealing with a troll.
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2712. Orcasystems
9:55 PM GMT on June 16, 2009
Quoting RitaEvac:
Example is the Houston media stations, when theres a depression in the Carribbean that MAY come into the Gulf....guess what.... thats the top breaking news story! something that not even remotely needs to be discussed, no wonder it was so nice living in the old days, they didnt care and didnt need to worry about everything. If Wall Street didnt get publicized people would be forking money into it like crazy, but media scaring the hell outta everyone


lets se how you theory holds water.

No News:

1900: Known as "the Galveston Hurricane," the deadliest hurricane disaster in U.S. history occurred on September 8. More than 8,000 people died when hurricane storm tides (the surge plus the astronomical tide) of 8-15 feet inundated the entire island city of Galveston, Texas. More than half of all the homes and buildings were destroyed. Property damage is estimated at $700 million in 1990 dollars.

With News:

Ike was blamed for at least 195 deaths. Of these, 74 were in Haiti, which was already trying to recover from the impact of three storms earlier that year: Fay, Gustav, and Hanna. In the United States, 112 people were killed, and 34 are still missing.[5] Damages from Ike in US coastal and inland areas are estimated at $24 billion (2008 USD), with additional damage of $7.3 billion in Cuba, $200 million in the Bahamas, and $500 million in the Turks and Caicos, amounting to a total of $32 billion in damages. Ike was the third costliest U.S. hurricane of all time, behind Hurricane Andrew of 1992 and Hurricane Katrina of 2005.[5]


Your theory is wrong.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
2711. gator23
9:55 PM GMT on June 16, 2009
Quoting RitaEvac:
Example is the Houston media stations, when theres a depression in the Carribbean that MAY come into the Gulf....guess what.... thats the top breaking news story! something that not even remotely needs to be discussed, no wonder it was so nice living in the old days, they didnt care and didnt need to worry about everything. If Wall Street didnt get publicized people would be forking money into it like crazy, but media scaring the hell outta everyone


1. I work in Media
2. I studied media at length
3. I promise you we dont care to create a conspiracy.

That said, There are no old dayss Media has been around since the Roman times.
But thats ok you dont need media. So the next time a terrorist attack happens you wont know. Or after a hurricane if your water is unsafe to drink you wont know. Or if your driving to work and the expressway is jammed you wont know...
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2709. stormpetrol
9:53 PM GMT on June 16, 2009
Kinda sad when a person with not as much knowledge as them belittles others basically as mischievous children on vacation, I take back my acknowledgement of such person/s as positive contributors to this blog, on the other hand they are basically full of themselves with a SUPER EGO that will probably amount to nothing more, who the cap fit let them wear it!!!
Member Since: April 29, 2007 Posts: 0 Comments: 7682
2706. RitaEvac
9:49 PM GMT on June 16, 2009
Example is the Houston media stations, when theres a depression in the Carribbean that MAY come into the Gulf....guess what.... thats the top breaking news story! something that not even remotely needs to be discussed, no wonder it was so nice living in the old days, they didnt care and didnt need to worry about everything. If Wall Street didnt get publicized people would be forking money into it like crazy, but media scaring the hell outta everyone
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2705. gator23
9:49 PM GMT on June 16, 2009
Quoting RitaEvac:


Actually makes perfect sense, the media is the cause of all world problems, they stir up stuff that doesnt need to be. The less the world knew there wouldn't be all the problems today. So not classfying the 90L kept the hype down about the hurricane season. Media is only good to scare people and believe everything they say. Their idiots and I'm anti-media.


Got it so next time a Cat 5 is coming to your area...
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2704. Orcasystems
9:45 PM GMT on June 16, 2009
Quoting RitaEvac:


Actually makes perfect sense, the media is the cause of all world problems, they stir up stuff that doesnt need to be. The less the world knew there wouldn't be all the problems today. So not classfying the 90L kept the hype down about the hurricane season. Media is only good to scare people and believe everything they say. Their idiots and I'm anti-media.


If you hadn't pointed that out.. I doubt we would have been able to guess..
Member Since: October 1, 2007 Posts: 81 Comments: 26511
2702. Orcasystems
9:44 PM GMT on June 16, 2009
Blog Update
Reflector site for those at work, which now also includes Weather456, daily updates


AOI #1

AOI #2
Member Since: October 1, 2007 Posts: 81 Comments: 26511
2701. palmbaywhoo
9:44 PM GMT on June 16, 2009
agreed stormpetrol, well put, they may reasess this after the year, but as for now it is useless to continue pushing that it was a storm/depression or whatever
Member Since: August 18, 2008 Posts: 0 Comments: 387
2700. RitaEvac
9:42 PM GMT on June 16, 2009
Quoting hurricane2009:
I agree gator I am saying them not naming the system to fool the media makes no sense


Actually makes perfect sense, the media is the cause of all world problems, they stir up stuff that doesnt need to be. The less the world knew there wouldn't be all the problems today. So not classfying the 90L kept the hype down about the hurricane season. Media is only good to scare people and believe everything they say. Their idiots and I'm anti-media.
Member Since: July 14, 2008 Posts: 1 Comments: 9628
2699. gator23
9:42 PM GMT on June 16, 2009
Forget the NHC them and their PHD's,years of experience and thousands of thesis papers clearly dont know what they're talking about. When the winds pick up this season I am casting my vote with these bloggers to issue storm warnings and precise, accurate storm tracks and information.
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2698. RitaEvac
9:40 PM GMT on June 16, 2009
Buena Vista, Crunk Pandaville, Texas (PWS)
Updated: 4 min 40 sec ago
107.6 °F
Clear
Humidity: 35%
Dew Point: 74 °F
Wind: 9.0 mph from the SSE
Wind Gust: 13.0 mph
Pressure: 28.81 in (Falling)
Heat Index: 122 °F Visibility: 10.0 miles
UV: 10 out of 16
Clouds: Clear -
(Above Ground Level)
Elevation: 1053 ft

Member Since: July 14, 2008 Posts: 1 Comments: 9628
2696. gator23
9:36 PM GMT on June 16, 2009
Quoting hurricane2009:
play the game lol

that is what this world is coming to now, NHC doesnt name a storm to fool the media

That is really pathetic lol

They are not that organized to be that sinister. Same with the insurance argument. They live in Florida if anything they would be cautious about updating storms comign here.
Member Since: August 26, 2008 Posts: 0 Comments: 2162
2694. stormpetrol
9:33 PM GMT on June 16, 2009
My guess is ,that the NHC has a criteria they absolutely adhere to when it comes to declaring Invest/TDs/TSs, of course this is my assumption only.
Member Since: April 29, 2007 Posts: 0 Comments: 7682
2693. 0741
9:33 PM GMT on June 16, 2009
Quoting palmbaywhoo:


You guys should start your own hurricane center and rival the NHC and at the end of the year the general population can vote and see which one was better!
their only one nhc and only one none of you can do what nhc can do save life

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

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