East Pacific hurricane season kicks off

By: Dr. Jeff Masters , 2:03 PM GMT on May 30, 2006

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Hurricane season has begun in the Northeastern Pacific (the region off the west coast of Mexico), with the formation of Tropical Storm Aletta over the weekend. Aletta is expected to die by Thursday, a victim of high wind shear and dry air. At its peak, Aletta was only a weak tropical storm with top winds of 45 mph. The storm brought over two inches of beneficial rain to Acapulco, and ten inches to the surrounding mountains. Aletta is now moving away to the west over open ocean, bringing an end to the rains over Mexico.


Figure 1. Latest image of Aletta.

NOAA's 2006 forecast for the Northeastern Pacific hurricane season calls for a less active than usual year, with 12-16 named storms, 6-8 hurricanes, and 1-3 major Category 3 and stronger storms. On average, the Northeastern Pacific has 16 named storms, 9 hurricanes, and 4.5 major hurricanes. The pattern of upper level winds that favors an active hurricane season in the Atlantic typically brings high wind shear and low hurricane activity to the Northeastern Pacific. Last year's record breaking year in the Atlantic was balanced by a slightly below-average year in the Northeastern Pacific, which had 15 named storms, seven hurricanes, and two major hurricanes. The last three east Pacific hurricane seasons have been below normal, following an overall trend of lower activity since 1995. This is exactly the opposite of what has been observed in the Atlantic. "Since 1995, despite the trend to warmer waters in the tropical east Pacific, higher wind shear has contributed to fewer tropical storms, hurricanes, and major hurricanes," noted Muthuvel Chelliah, NOAA's Climate Prediction Center lead scientist on the east Pacific hurricane season outlook.

The Northeast Pacific basin hurricane season officially began May 15. The season has a broader peak than the Atlantic. Activity usually begins in late May or early June, and lasts until late October or early November. Peak storminess occurs in late August/early September. Only three Eastern Pacific hurricanes have had their names retired--Hurricane Ismael of 1995, Hurricane Pauline of 1997, and Hurricane Kenna of 2002, all of which hit Mexico. In addition, Adolph and Israel of 2001 had their names retired for political reasons.

I'll be back Wednesday with a look at Bill Gray's latest Atlantic hurricane season forecast, due to be issued tomorrow.

Jeff Masters

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207. 53rdWeatherRECON
3:36 PM GMT on May 31, 2006
Weaker trade winds have led to anomalous warming of the tropical Atlantic since the early part of April. We therefore continue to expect that another very active hurricane season is likely for the Atlantic basin.


HAHAHAHAHAH!!!!!!!!!! Anomolous Warming. GET USED TO IT MORONS.

Once this thing (greenhouse effect) really gets up to speed there is no stopping it. We were warned for years now we pay.

I LOVE IT.

Nobody cares about coral reefs and stupid glaciers or polar bears. Maybe after one of these suckers puts 3 million people in NY city under water. NOW MAYBE YOU WILL START CARING.

Array_B

Good Luck NY, Boston, Virginia, Washington you will certainly need it this year
Member Since: August 5, 2005 Posts: 2 Comments: 80
206. gninraelyrt
3:36 PM GMT on May 31, 2006
It looks like there's high confidence in Tropical disturbances this year with many bloggers choosing 20 or more. The interesting spin on this is seeing the Gulf of Mexico and southeast coasts warmer waters. These storms named or not, will mostly develop in these environments, correct? If so, what states if any should take additional steps in preparing for a Cat3 or higher hurricane? All southern coastal states along the Gulf of Mexico and the Atlantic? May I guess that Texas, North Carolina, Mississippi, and Florida are at an even higher risk this year? This is not my wish of course. I'd prefer that no hurricane make landfall, but if any strong weather disturbance makes its way into the aforementioned environments, these states should be on heightened alert, right? I didn't say Louisiana because I can't fathom that based on a comparison of land mass. Distance coast to coast is most favorable for storms to strike Texas and Florida. North Carolina was mentioned because is fits into the model of a possible northern tracking east coast hit. And I'm guessing Mississippi instead of Alabama and Lousiana because it lies within a dangerous path (current loop storm energizer) should a strong hurricane get around Cuba and Florida. Please tell me all my landfall predictions are unsubstantiated and completely false and I'll feel much better. I don't want to scare anybody. I'M NO EXPERT. Storm tracking models frequently send tropical storms toward Florida and Texas. Mississippi would be an unfortunate disaster. North Carolina would only benefit from a long-winded tropical storm's journey that would not stay in it's strongest category to get that far. Please post comments.
205. IKE
3:19 PM GMT on May 31, 2006
A new blog by Dr. Masters on Dr. Gray's predictions.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
204. Cavin Rawlins
3:13 PM GMT on May 31, 2006
4 ENSO



We believe that neutral ENSO conditions are likely to be present during August-October 2006. A weakening La Niņa event was observed in the eastern and central tropical Pacific over the past few months. Sea surface temperatures have warmed somewhat over the past couple of months, and according to the Climate Prediction Center (CPC), neutral ENSO conditions are currently observed. However, Southern Oscillation Index (SOI) values remain positive, trade winds in the central Pacific have remained fairly strong, and oceanic heat content in the western and central Pacific is not particularly warm. We therefore do not expect El Niņo conditions to develop this summer. In addition, most forecast models call for neutral ENSO conditions to persist for the next 4-6 months. When the tropical Atlantic is warm and neutral ENSO conditions are present, Atlantic basin hurricane activity is enhanced.

These important abstracts
Member Since: July 24, 2005 Posts: 407 Comments: 19076
203. SavannahStorm
3:12 PM GMT on May 31, 2006
Oops, you beat me to it.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
202. SavannahStorm
3:12 PM GMT on May 31, 2006
Thanks! Check out the landfall probabilities!



PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS:



1) Entire U.S. coastline - 82% (average for last century is 52%)



2) U.S. East Coast Including Peninsula Florida - 69% (average for last century is 31%)



3) Gulf Coast from the Florida Panhandle westward to Brownsville - 38% (average for last century is 30%)



4) Above-average major hurricane landfall risk in the Caribbean

Member Since: September 22, 2005 Posts: 18 Comments: 2343
201. Cavin Rawlins
3:11 PM GMT on May 31, 2006


PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS:



1) Entire U.S. coastline - 82% (average for last century is 52%)



2) U.S. East Coast Including Peninsula Florida - 69% (average for last century is 31%)



3) Gulf Coast from the Florida Panhandle westward to Brownsville - 38% (average for last century is 30%)



4) Above-average major hurricane landfall risk in the Caribbean
Member Since: July 24, 2005 Posts: 407 Comments: 19076
200. Cavin Rawlins
3:08 PM GMT on May 31, 2006
the update is out!
Member Since: July 24, 2005 Posts: 407 Comments: 19076
199. rwdobson
3:07 PM GMT on May 31, 2006
"system" off texas is forming an upper low at 28N 95W, according to the latest discussion. it sure looks like a classic non-tropical low with a well defined comma shape.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
198. SavannahStorm
3:06 PM GMT on May 31, 2006
Anyone have a link to the updated forecast from Dr. Gray?
Member Since: September 22, 2005 Posts: 18 Comments: 2343
197. FLCrackerGirl
3:05 PM GMT on May 31, 2006
23 Named Storms...I Think We'll See The
Greeks Again. (Alpha06 & Beta06)
Member Since: August 12, 2004 Posts: 47 Comments: 597
196. gninraelyrt
2:56 PM GMT on May 31, 2006
Your input is appreciated HurricaneMyles, ForcasterColby, and snowboy. Looks like I misunderstood the condition of Wilma's fast exit. It makes total sense that the jet stream would be able to move the system out all on it's own. I get really nervous when a fast moving jet stream is approaching the Twin Cities when the temperatures are in the 90s and the humidity is pushing 70% or better. For some reason, the storms tend to spawn more just to the north or just to the south of the metro. Does this have anything to do with man-made structures obscuring a weather pattern or many bodies of waters nearby? BTW, we rarely experience dry thunder like out in the Dakotas. I'm thankful for that. We vacationed there 25 years ago during a bad storm and I had ringing in my ears for hours from all that crackling. Also, Is it accurate to say that dry lightning is possibly more dangerous than moist lightning? (the damage that may result aside from fire). Do multiple consecutive strikes of branched lightning weaken a storm system or would a single magnificent blast do more harm or is this all irrelevant for storm development? Your thoughts please.
195. newt3d
2:48 PM GMT on May 31, 2006
20 named storms, with 4+ coming after 31 October.
Member Since: October 6, 2005 Posts: 0 Comments: 90
194. 53rdWeatherRECON
2:41 PM GMT on May 31, 2006
22 Named storms
Member Since: August 5, 2005 Posts: 2 Comments: 80
193. snowboy
2:34 PM GMT on May 31, 2006
gninraelyrt, you know I tried reading it backwards and missed it first time through.. LOL

The only sage advice I can offer is enjoy the huge variety of fascinating blogs in the WU world, steer clear of conflicts (which do arise from time to time), and don't let it consume you..

This is the main blog, which most everyone checks and which many post in - there is an air of cautious anticipation just now as we await the start of what many are predicting will be another wild hurricane season.

Enjoy the ride.
Member Since: September 21, 2005 Posts: 10 Comments: 2547
192. ForecasterColby
2:32 PM GMT on May 31, 2006
Shear is harmful to storms once you get over about 10kt, and above 25-30 is usually going to stop any development. Wilma was an odd exception, she used an unusually far south branch of the Jet Stream as an outflow channel on her approach to Florida. The shear was not actually over her, it was slightly to her north. The "big push" was the Stream catching Wilma and blowing her rapidly northeast, so quickly that she went extratropical while still a hurricane.
191. TheBoomer
2:31 PM GMT on May 31, 2006
Klotzbach and Gray have released the updated forecast.

No change from april 4th, still at 17 named storms.
190. HurricaneMyles
2:31 PM GMT on May 31, 2006
Gninraelyrt,

Windshear is almost 100% bad for tropical systems. There might have been a few times a little windshear has done a tropical storm some good, but I have never seen them.
Generally windshear above 15kts is pretty unfavorable for tropical cyclone development. This will keep a TD from strengthening into a hurricane. 30kts of shear will normally rip the cloudtops off even a mature hurricane and dramatically weaken it.

The shear Wilma expeirienced was a bit different. It was referred to a storm relative shear. Even though Wilma was under 20-30kts of shear in the upper-levels, she was moving at 15-20kts at the surface so the shear affected her less.
Member Since: January 12, 2006 Posts: 5 Comments: 827
189. gninraelyrt
2:28 PM GMT on May 31, 2006
Correction to earlier post wind shear 30 kt. Thanks and please post your thoughts.
188. gninraelyrt
2:24 PM GMT on May 31, 2006
Hey snowboy, No deciphering is necessary. You only need to read it backwards to understand. In some countries, literature is read from right to left, but not as I've typed this one of course. Thanks for the welcome! Do you have wisdom to pass along to me and the weather rookies?
187. Hellsniper223
2:21 PM GMT on May 31, 2006
24 storms...

Bit radical, eh? Well, I'm just that way. I'm going to say we are short one more city this year. Probably on the east coast.
Member Since: March 28, 2006 Posts: 0 Comments: 16
186. gninraelyrt
2:19 PM GMT on May 31, 2006
Is wind-shearing always destructive to hurricane development when they are < 30 kt? I've heard that it can really fiddle with the reintensification cycles of strengthening hurricanes and basically keep TD's from becoming hurricanes. Is this a correct statement? Didn't Hurricane Wilma last year get a big push as it made it's way through Florida, or was that just surface winds that pushed Wilma out of the Gulf and not the wind shear (mid to upper level wind disturbance)? Can someone take a little time to explain this? Thanks!
184. snowboy
2:08 PM GMT on May 31, 2006
welcome aboard, gninraelyrt! That handle is a mouthful! Are we supposed to unsramble the letters to find a hidden meaning?
Member Since: September 21, 2005 Posts: 10 Comments: 2547
183. FlaRob
2:05 PM GMT on May 31, 2006
I would venture a guess of 15 named storms.
182. Cavin Rawlins
2:05 PM GMT on May 31, 2006
12 named storms, 6-7 hurricanes and 1 or 2 major......

Question: is high wind shear in Late May- Early June a prediction of the season overall?

Was the May-June 2005 wind sheer this high a cross the Caribbean Sea, Gulf of mexico and Atlantic?
Member Since: July 24, 2005 Posts: 407 Comments: 19076
180. KShurricane
2:04 PM GMT on May 31, 2006
I say 17 named storms.
178. snowboy
2:03 PM GMT on May 31, 2006
MichaelSTL, thanks for the link.

I would agree that the global trend towards increases in hurricane intensity may be due to global warming from greenhouse gas emissions BUT those who are experts in the field are firmly of the opinion that the higher number of hurricanes in the Atlantic basin in recent years is just part of a long-term natural pattern.
Member Since: September 21, 2005 Posts: 10 Comments: 2547
177. gninraelyrt
2:02 PM GMT on May 31, 2006
Hey WSI and weatherboyFSU. I'm very new to this whole Atlantic basin MCC stuff. What kind of data do you use to be able to make predictions like the ones listed for 2005? Are these predictors educated in the field of Atlantic storm-based study? Not being educated at all about hurricanes, what would it take for me to be able to contribute to this blog? I'd like to comment that I think meteorology is fun and living in Minnesota gives a weather junkie alot of different looks at weather patterns thanks to frequent passes of the jet stream. I also have a wife who makes an incredible weather gauge. She senses storm activity and severity before the news covers it that same day. Do you guys enjoy looking at the weather disturbances or just talking with everybody in the forum because it's a fun group to be in? I don't make predictions. I'm no expert, but I'm interested. And if you don't mind, I'd like to participate in this weather forum. I'll try to be impartial and intelligent. Thanks.
176. snowboy
1:55 PM GMT on May 31, 2006
22 named storms, 5 major hurricanes ..
Member Since: September 21, 2005 Posts: 10 Comments: 2547
174. WSI
1:43 PM GMT on May 31, 2006
I say 18 named storms.
173. weatherboyfsu
1:38 PM GMT on May 31, 2006
Good Morning Everyone............Its that time again to make your prediction for this Hurricane Season. Below is a the list from last year........

Please email me with your prediction and also type it in here for confirmation. Remember, no revising in a week, a month, etc......

LAST YEARS PREDICTIONS!!!!!!

moocrew - 20
alec - 16
WSI - 17
DEB1 - 24
Turtlehurricane - 19
canenut - 16
K8e1 - 11
Toyotaman - 18
kjcanon - 13
cjnew - 18
isobar5 - 22
hurricaneking - 21
corpuswatch - 17
emmyrose - 12
orionbarkwood - 18
stsimonsisland - 16
hootythebooty - 22
outrocket - 14
txweather - 18
stormtop - 20
raysfan - 16
orlandocavewatcher - 19
cherikem - 20
tornadoty - 24
nicolai - 18
weatherboyfsu - 14


Get me your prediction..........I think a week should be long enough......after that no revising and im not going to except any more........

Member Since: July 17, 2005 Posts: 0 Comments: 1025
172. Tazmanian
3:52 AM GMT on May 31, 2006
...Tropical waves...
Tropical wave is along 41w S of 14n moving W about 15 kt. This
wave has well-defined cyclonic turning on satellite imagery. In
addition...a wind shift and low-mid level vorticity structure is
evident. This wave is assisting in triggering numerous showers
and tstms within several hundred miles of the wave axis within
the ITCZ.
Member Since: May 21, 2006 Posts: 5091 Comments: 115235
171. HadesGodWyvern (Mod)
3:49 AM GMT on May 31, 2006
THE WAVE WILL LIKELY MOVE INTO THE EPAC TOMORROW
AFTERNOON/NIGHT AND A FEW MODELS INDICATE THAT THE WAVE MAY
BECOME SLIGHTLY BETTER DEFINED BY THEN.

So.. confirmation of possible 02-E developement that models are showing for later this week?
Member Since: May 24, 2006 Posts: 51 Comments: 45593
170. WSI
3:36 AM GMT on May 31, 2006
"Where does the data for the Wunderground shear forecast come from"

AVN (Aviation Model) - 200 hPa - 850 hPa wind shear

169. Tazmanian
3:32 AM GMT on May 31, 2006
...Tropical waves...
Tropical wave is along 41w S of 14n moving W about 15 kt. This
wave has well-defined cyclonic turning on satellite imagery. In
addition...a wind shift and low-mid level vorticity structure is
evident. This wave is assisting in triggering numerous showers
and tstms within several hundred miles of the wave axis within
the ITCZ.
Member Since: May 21, 2006 Posts: 5091 Comments: 115235
168. StellarCyclone
3:23 AM GMT on May 31, 2006
Good night all. It's all beginning now. Hopefully there will be no catastrophic landfalls. God bless!
167. bappit
2:32 AM GMT on May 31, 2006
Nice little gust front shown in last 40 frames from Houston radar. Also, the sheared circulation shows up nicely in the Gulf.

Member Since: May 18, 2006 Posts: 10 Comments: 6061
166. Cavin Rawlins
2:15 AM GMT on May 31, 2006
TROPICAL WAVE IS INLAND OVER SOUTH AMERICA ALONG 74W S OF 12N
MOVING W NEAR 10 KT. WAVE PLACEMENT IS BASED UPON CONTINUITY OF
THE MOVEMENT OVER THE PAST 24-48 HOURS AS LITTLE WAVE SIGNATURE
IS EVIDENT. THE WAVE WILL LIKELY MOVE INTO THE EPAC TOMORROW
AFTERNOON/NIGHT AND A FEW MODELS INDICATE THAT THE WAVE MAY
BECOME SLIGHTLY BETTER DEFINED BY THEN.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
165. weatherguy03
2:15 AM GMT on May 31, 2006
No idea Michael. But the shear is rather high. It was obvious today just by looking at that area of convection off the Texas coast.
Member Since: July 5, 2005 Posts: 592 Comments: 29705
163. WSI
2:03 AM GMT on May 31, 2006
what high shear in the gulf?

How about here...


Or here...

Or maybe here...


It's there. :)
162. ForecasterColby
2:02 AM GMT on May 31, 2006
"TROPICAL WAVE IS ALONG 41W S OF 14N MOVING W ABOUT 15 KT. THIS
WAVE HAS WELL-DEFINED CYCLONIC TURNING ON SATELLITE IMAGERY. IN
ADDITION...A WIND SHIFT AND LOW-MID LEVEL VORTICITY STRUCTURE IS
EVIDENT. THIS WAVE IS ASSISTING IN TRIGGERING NUMEROUS SHOWERS
AND TSTMS WITHIN SEVERAL HUNDRED MILES OF THE WAVE AXIS WITHIN
THE ITCZ."

- From the 8:05 Atlantic TWD. They sound awfully optimistic about a wave that doesn't even seem to be there; the only convection is way to the south in the ITCZ.

Oh and this high shear in the gulf. Above 20kt is unfavorable, above ~ 40 is fatal.
160. Tazmanian
1:53 AM GMT on May 31, 2006
what high shear in the gulf?
Member Since: May 21, 2006 Posts: 5091 Comments: 115235
159. Inyo
1:48 AM GMT on May 31, 2006
Posted By: StormMan at 11:43 PM GMT on May 30, 2006.
I apologize if this is redundant but someone was questioning whether or not you can see 'dust' in the air (such as sand off West Coast of Africa)...the answer is yes you can:

http://toms.gsfc.nasa.gov/aerosols/aerosols_v8.html

and...

http://visibleearth.nasa.gov/view_rec.php?id=927

-StormMan


Maybe you were talking about me.. stormtop said he saw dust in the water vapor imagery... you CAN see dust with satellite date but not WV imagery, i don't think.


Sad news about the meteorologist who is battling Parkinson's... my grandmother also suffers from this... it's not fun.



lightning10, i imagine the next above average E-Pac season will come along with the next El Nino which we should be due for in the next 3 or 4 years.
Member Since: September 3, 2002 Posts: 42 Comments: 873
158. hurricane23
1:39 AM GMT on May 31, 2006
hey guys whats up....ive been watching this blob in the gulf and to me there will not be any development because the Subtropical jet is progged to weaken temporarily but shear is forcast to increase again so iam not really lookin for to much out of this....

PS!I ALSO WANTED TO PASS ON THAT BILL GRAY WILL BE RELEASING HIS UPDATE TO THE PUBLIC AT 10:00 EST.
Member Since: May 14, 2006 Posts: 8 Comments: 13804
157. newt3d
12:39 AM GMT on May 31, 2006
The "system" off Texas is sucking in dry air on the west ... makes sense since it formed on the dry line of a couple days ago.
Member Since: October 6, 2005 Posts: 0 Comments: 90

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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.