2007 Hurricane Season Forecast

By: Dr. Jeff Masters , 5:50 PM GMT on December 08, 2006

Share this Blog
3
+

It's going to be a more active than usual Atlantic hurricane season in 2007, but not hyperactive, according to the latest seasonal forecast issued by Dr. Bill Gray and Phil Klotzbach of Colorado State University today. The Gray/Klotzbach team is calling for 14 named storms, 7 hurricanes, and 3 intense hurricanes. An average season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. The forecast calls for an above normal chance of a major hurricane hitting the U.S., both along the East Coast (40% chance, 31% chance is normal) and the Gulf Coast (40% chance, 30% chance is average).

The forecasters predict that the current moderate El Nino event will dissipate by the time the active part of the 2007 hurricane season rolls around. The sudden development of El Nino this year significantly reduced the hurricane activity, and dissipation of this El Nino by August of 2007 would likely create more favorable conditions for hurricane development than in 2006. Gray and Klotzbach support this forecast by examining the active hurricane periods of 1950-1969, and 1995-2005, and note that seven out of the eight seasons following El Nino years during this period were active Atlantic hurricane seasons, and all of these years witnessed either neutral or La Nina conditions.

The forecasters examined the observed atmospheric conditions and ocean temperatures in October-November 2006, and came up with a list of four past years that had a similar combination of a moderate El Nino event, warmer than average tropical Atlantic SSTs, and a weaker-than-normal Azores-Bermuda High. We can expect 2007 to be similar to the average of these four analogue years, they say. The four years were 2003 (16 named storms, 7 hurricanes, 3 intense hurricanes), 1966 (11, 7, and 3 of the same), 1958 (10, 7 and 5), and 1952 (7, 6 and 3). Hurricane Isabel of 2003 (Category 2) was the strongest hurricane to hit the U.S. in these four analogue years, and Category 4 Hurricane Inez of 1966 caused the most death and destruction, killing over 1000 people in its rampage through the Caribbean.

2007 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
It's going to be a bit rougher year than the Gray/Klotzbach team is forecasting, according to the British private forecasting firm Tropical Storm Risk, Inc. (TSR), who issued their 2007 Atlantic hurricane season forecast yesterday. TSR is calling for a season with 60% above normal activity--16 named storms, 9 hurricanes, and 4 intense hurricanes. They project that five named storms will hit the U.S., with two of these being hurricanes. In the Lesser Antilles Islands of the Caribbean, TSR projects two named storms, one of them being a hurricane. TSR cites two main factors for their forecast of an active season: above normal Sea Surface Temperatures (SSTs) are expected in August-September 2007 across the tropical Atlantic, as well as slower than normal trade winds. Trade winds are forecast to be 0.7 meters per second (about 1.5 mph) slower than average, which would create greater spin for developing storms, and allow the oceans to heat up due to reduced evaporational cooling. SSTs are forecast to be about 0.34 degrees C above normal. TSR gives an 80% chance that the 2007 Atlantic hurricane season will rank in the top third of active seasons observed since 1957.


Figure 1. Accuracy of long-range forecasts of Atlantic hurricane season activity performed by Bill Gray and Phil Klotzbach of Colorado State University (colored squares) and TSR (colored lines). The skill is measured by the Mean Square Skill Score (MSSS), which looks at the error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TS=Tropical Storms, H=Hurricanes, IH=Intense Hurricanes, ACE=Accumulated Cyclone Energy, NTC=Net Tropical Cyclone Activity. Image credit: TSR.

How good are these December hurricane season forecasts? Unfortunately, they're pretty much worthless. The skill of the December forecasts issued by Dr. Gray and TSR (Figure 1) have averaged near zero since 1992. Not surprisingly, the forecasts get better the closer they get to hurricane season. The June and August forecasts show some modest skill, and are valuable tools for insurance companies and emergency planners to help estimate their risks. The problem with the December forecasts is that the current statistical computer models used to forecast El Nino are not skillful beyond about six months. For example, none of these models foresaw the current El Nino event that began in September--until April. Until we can forecast the evolution of El Nino more than six months in advance, these December forecasts are not worth paying much attention to. I think it's important for these groups to keep trying, though.

I'll be back Monday with a new blog. Tune into the blog of Mike Theiss this weekend, he'll be covering the launch of the Space Shuttle. Mike is a top notch storm chaser and weather photographer we're excited to have on our wunderblogging team!

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 149 - 99

Page: 1 | 2 | 3Blog Index

147. aspiringstat
9:08 AM GMT on December 10, 2006
NDCC MEDIA UPDATE
re Typhoon “Seniang“ (Utor)
Releasing Officer:
GLENN J RABONZA
Administrator, OCD and
Executive Officer, NDCC
DATE: 10 December 2006 as of 12:00 NN
1. WEATHER UPDATE
· Typhoon “Seniang” is now over the Southern tip of Oriental Mindoro and heading
towards the Calamian Group of Islands. At 10:00 AM today, the eye of Typhoon
Seniang was located based on satellite and surface data at 50 kms East of San Jose,
Occidental Mindoro (12.4°N, 121.4°E) with maximum sustained winds of 120 kph near
the center and gustiness of up to 150 kph moving west northwest at 17 kph.
· It is expected to pass close to Coron, Palawan early tonight. By tomorrow morning it will
be at 250 kms Northwest of Coron, Palawan and will be over the South China Sea by
Tuesday morning.
PSWS #3 - Southern Occidental Mindoro, Southern Oriental Mindoro,
and Calamian Group of Island
PSWS #2 - Rest of Mindoro, Lubang Island, Romblon, Aklan, Antique and Cuyo
Island
PSWS #1 - Masbate, Sorsogon, Albay, Burias Island, Camarines Norte and Sur,
Marinduque, Batangas, Southern Quezon, Laguna, Cavite, Bataan,
Metro Manila, Iloilo, Guimaras, Capiz and Northern Palawan
Public Storm Warning signals elsewhere are now lowered.
2. EARLY WARNING
· Residents in areas under Public Storm Warning Signals 3, 2, and 1 are alerted against
flashfloods, landslides and possible storm surges or big waves.
· PDCCs with areas near active volcanoes (Bulusan, Kanlaon, Pinatubo, Mayon, Hibok-
Hibok and other active volcanoes) are advised to be prepared for flashfloods and
sediment laden flows like lahars/mudflows.
· Those residing in coastal areas under PSWS No 3 are advised to seek higher grounds
due to possible storm surges and big waves.
· The public and the disaster coordinating councils concerned are advised to take
appropriate actions and watch for the next bulletin to be issued at 5:00PM today.
3. EFFECTS
Casualties
Dead (2)
· one (1) in Bgy. Bagacay Tacloban City and one from Panay, Capiz identified as
Angeline Besana, 1 y/o, F (house was toppled by a tree)
2
Injured (3)
· One (1 in Tanauan, Leyte (hit by fallen tree) , one (1) in Tacloban City and one in
Panay, Capiz identified as Ednalyn Besana, 29 y/o, F (house was toppled by a tree)
Missing (3)
· Three (3) missing in Roxas City due to drowning namely Paquito Recto, Dolly Adrenosin
and Jonard Adrenosin
Affected /Evacuated (Tab A)
· A total of 17,683 families or 91,121 persons in Regions IV-B, V, VII and VIII were
affected while 17,525 families or 90,295 persons were evacuated in 59 evacuation
centers
· Stranded Passengers and Transportation (Tab B)
A total of 8,983 passengers, 97 buses, 126 trucks, 119 light Cars/Vehicles, 103
vessels/motor bancas and 260 rolling cargoes are stranded in various ports of Regions
IV-B, V, VII and VIII
Damaged Properties
Region VII
· Two (2) and one (1) elementary classrooms were totally and partially damaged in Bgy
Tarong
· Five (5) houses along the coastline were totally damaged due to big waves, however,
families were safely evacuated prior to the incident
· Ten (10) houses and one house were partially and totally damaged in the Municipality of
Tudela
Status of Lifelines
Power
Region IV-B
· No power in the whole province of Marinduque
Region VI
· Power blockout in Pilar and Roxas City, Capiz due to tripping of TRANSCO lines
Region VII
· Only Batayan Island is without power
Region VIII
· Region wide power black-out except the province of Southern Leyte
· Power will be restored within the week
Communication
Region VII
· Cellular phone signals in the northern part of Cebu are back to normal since this
morning
146. Patrap
4:44 AM GMT on December 10, 2006
Hurricanes ,Tornadoes..and Wind Shear...Link
Member Since: July 3, 2005 Posts: 428 Comments: 129844
145. weatherboykris
4:31 AM GMT on December 10, 2006
Does a hurricane under a lot of wind shear create more tornados than one under little wind shear?
Member Since: December 9, 2006 Posts: 125 Comments: 11346
144. weatherboykris
4:00 AM GMT on December 10, 2006
Forecast discussions for Andrew
Link
Member Since: December 9, 2006 Posts: 125 Comments: 11346
143. HadesGodWyvern (Mod)
3:52 AM GMT on December 10, 2006
incredible that PAGASA didn't raise the sustained winds to 150 kph (80 knots) or higher

they maintained the sustained winds at 120 kph which is about 65 knots O_0'

Member Since: May 24, 2006 Posts: 52 Comments: 46914
142. weatherboykris
3:49 AM GMT on December 10, 2006
18z GFS has a storm forming of the Bahamas

18z GFS
Member Since: December 9, 2006 Posts: 125 Comments: 11346
141. weatherboykris
3:46 AM GMT on December 10, 2006
Utor's looking good tonight.

Member Since: December 9, 2006 Posts: 125 Comments: 11346
139. Skyepony (Mod)
3:00 AM GMT on December 10, 2006
See while I was out Utor went right from a cat 1 to 3. See Randrewl I can be wrong..lol.
I called 1 & 2 across the Philippines... This isn't good at all though, I'm sure the west side was expecting
less of a storm, not this.


The launch was beautiful.
Member Since: August 10, 2005 Posts: 225 Comments: 39388
138. hurricane23
2:35 AM GMT on December 10, 2006
Utor's winds are up to 115 mph and is now expected to reach CAT5 intensity in the next day or two.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
137. HIEXPRESS
2:05 AM GMT on December 10, 2006
Clear sky - great view!
Member Since: October 13, 2005 Posts: 4 Comments: 2156
136. Patrap
1:49 AM GMT on December 10, 2006
Discovery Launches on time....
Member Since: July 3, 2005 Posts: 428 Comments: 129844
132. ProgressivePulse
1:44 AM GMT on December 10, 2006
QUICKSCATT LINK

Nothing showing!
Member Since: August 19, 2005 Posts: 5 Comments: 5458
131. hurricane23
1:43 AM GMT on December 10, 2006
100kt winds now on Utor...


Member Since: May 14, 2006 Posts: 8 Comments: 13841
130. hurricane23
1:40 AM GMT on December 10, 2006
cyclonebuster once Utor moves into the south china sea steady strengthing looks very likely to me.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
127. hurricane23
1:35 AM GMT on December 10, 2006
MM5 was put to rest way back in october till next season.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
126. hurricane23
1:33 AM GMT on December 10, 2006
I think Utor is going under rapid intensifcation as winds are now up to 100kts...
Member Since: May 14, 2006 Posts: 8 Comments: 13841
125. Drakoen
1:19 AM GMT on December 10, 2006
anyone have a pic or link for the latest windscatt of the Carribean?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
124. philliesrock
1:14 AM GMT on December 10, 2006
Oops sorry everybody. My bad.
Member Since: June 29, 2006 Posts: 65 Comments: 3197
122. philliesrock
1:10 AM GMT on December 10, 2006
Storms in the Atlantic and Pacific???? I don't think so.
????????
Member Since: June 29, 2006 Posts: 65 Comments: 3197
119. philliesrock
1:01 AM GMT on December 10, 2006
Hmmmmm...where's the eye? I can't find it!!!

utor
Member Since: June 29, 2006 Posts: 65 Comments: 3197
116. philliesrock
12:55 AM GMT on December 10, 2006
utor
Member Since: June 29, 2006 Posts: 65 Comments: 3197
113. Drakoen
12:46 AM GMT on December 10, 2006
hmm whats the latest windscatt of the Carribean?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
110. Drakoen
12:37 AM GMT on December 10, 2006
whats the navy site?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
109. HIEXPRESS
12:26 AM GMT on December 10, 2006
Seems to be a low developing in the NW Carrib.

There could be a window of reduced shear, & the GFS seems to like it a little, but all this cold air headed south over my house agrees with the TPC Discussion: "THE FRONT OR MORE LIKELY
REMNANT TROUGH WILL SLOWLY WEAKEN OVER THE NEXT FEW DAYS".
Member Since: October 13, 2005 Posts: 4 Comments: 2156
107. Drakoen
12:17 AM GMT on December 10, 2006
are all the models indicating development in that general area?
Member Since: October 28, 2006 Posts: 57 Comments: 30830
106. Wishcasterboy
11:49 PM GMT on December 09, 2006
I have updated my blog everyone.
105. ProgressivePulse
11:37 PM GMT on December 09, 2006
A little closer to home it should be interesting to see this evenings windscatt. Seems to be a low developing in the NW Carrib.
Member Since: August 19, 2005 Posts: 5 Comments: 5458
104. TayTay
11:25 PM GMT on December 09, 2006
Unbelievable. A fifth storm doing this.
103. hurricane23
11:19 PM GMT on December 09, 2006
Models take Utor west then NW to NNW.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
102. hurricane23
11:11 PM GMT on December 09, 2006

Member Since: May 14, 2006 Posts: 8 Comments: 13841
101. Patrap
11:10 PM GMT on December 09, 2006
Heres another one but I dont Know the Location in the Phillipines..it refreshes every 15secs and is raining here..Link
Member Since: July 3, 2005 Posts: 428 Comments: 129844
100. Patrap
11:05 PM GMT on December 09, 2006
Can anyone find a webcam south of this one in Manila?Link..its Morning there now....
Member Since: July 3, 2005 Posts: 428 Comments: 129844
99. Patrap
11:01 PM GMT on December 09, 2006
The event is Occuring over the Phillipines poor..again.
Member Since: July 3, 2005 Posts: 428 Comments: 129844

Viewing: 149 - 99

Page: 1 | 2 | 3Blog Index

Top of Page

About

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

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron