More pre-season predictions of a very active Atlantic hurricane season

By: Dr. Jeff Masters , 3:02 PM GMT on July 12, 2010

Share this Blog
5
+

Hello again, it's Jeff Masters back again after a week away. Well, the past week was a wicked hot time to be in New England, where I was vacationing, and I certainly didn't expect to see 98° temperatures in Maine like I experienced! Fortunately, it's not hard to find cold water to plunge into in New England. Thankfully, the tropics were relatively quiet during my week away, and remain so today. There are no threat areas in the Atlantic to discuss at present, and none of the reliable computer models is forecasting tropical cyclone development over the next seven days. The NOGAPS model does show a strong tropical disturbance developing near the waters offshore of Nicaragua and Honduras this weekend, though. With not much to discuss in the present-day tropics, let's take a look at more pre-season predictions of the coming Atlantic hurricane season.

2010 Atlantic hurricane season forecast from Penn State
Dr. Michael Mann and graduate student Michael Kozar of Penn State University (PSU) issued their 2010 Atlantic hurricane season forecast on May 28. Their forecast utilizes a statistical model to predict storm counts, based on historical activity. Their model is predicting 19 to 28 named storms in the Atlantic, with a best estimate of 23 storms. The forecast assumes that record warm SSTs will continue in the Atlantic Main Development Region for hurricanes. Dr. Mann has issued two previous forecasts, in 2007 and 2009. The 2007 forecast was perfect--15 storms were predicted, and 15 storms occurred. The 2009 forecast called for 11.5 named storms, and 9 occurred (the 2009 forecast also contained the caveat that if a strong El Niño event occurred, only 9.5 named storms were expected; a strong El Niño did indeed occur.) So, the 2009 forecast also did well.


2010 Atlantic hurricane season forecast from the UK GloSea model
A major new player in the seasonal Atlantic hurricane season forecast game is here--the UK Met Office, which issued its first Atlantic hurricane season forecast in 2007. The UK Met Office is the United Kingdom's version of our National Weather Service. Their 2010 Atlantic hurricane season forecast calls for 20 named storms, with a 70% chance the number will range between 13 and 27. They predict an ACE index of 204, which is about double the average ACE index.

I have high hopes for the UK Met Office forecast, since it is based on a promising new method--running a dynamical computer model of the global atmosphere-ocean system. The CSU forecast from Phil Klotzbach is based on statistical patterns of hurricane activity observed from past years. These statistical techniques do not work very well when the atmosphere behaves in ways it has not behaved in the past. The UK Met Office forecast avoids this problem by using a global computer forecast model--the GloSea model (short for GLObal SEAsonal model). GloSea is based on the HadGEM3 model--one of the leading climate models used to formulate the influential UN Intergovernmental Panel on Climate Change (IPCC) report. GloSea subdivides the atmosphere into a 3-dimensional grid 0.86° in longitude, 0.56° in latitude (about 62 km), and up to 85 levels in the vertical. This atmospheric model is coupled to an ocean model of even higher resolution. The initial state of the atmosphere and ocean as of June 1, 2010 were fed into the model, and the mathematical equations governing the motions of the atmosphere and ocean were solved at each grid point every few minutes, progressing out in time until the end of November (yes, this takes a colossal amount of computer power!) It's well-known that slight errors in specifying the initial state of the atmosphere can cause large errors in the forecast. This "sensitivity to initial conditions" is taken into account by making many model runs, each with a slight variation in the starting conditions which reflect the uncertainty in the initial state. This generates an "ensemble" of forecasts and the final forecast is created by analyzing all the member forecasts of this ensemble. Forty-two ensemble members were generated for this year's UK Met Office forecast. The researchers counted how many tropical storms formed during the six months the model ran to arrive at their forecast of twenty named storms for the remainder of this hurricane season. Of course, the exact timing and location of these twenty storms are bound to differ from what the model predicts, since one cannot make accurate forecasts of this nature so far in advance.

The grid used by GloSea is fine enough to see hurricanes form, but is too coarse to properly handle important features of these storms. This lack of resolution results in the model not generating the right number of storms. This discrepancy is corrected by looking back at time for the years 1989-2002, and coming up with correction factors (i.e., "fudge" factors) that give a reasonable forecast.

The future of seasonal hurricane forecasts using global dynamical computer models is bright. Their first three forecasts have been good. Last year the Met Office forecast was for 6 named storms and an ACE index of 60. The actual number of storms was 9, and the ACE index was 53. Their 2008 forecast called for 15 named storms, and 15 were observed. Their 2007 forecast called for 10 named storms in July - November, and 13 formed. A group using the European Center for Medium Range Weather Forecasting (ECWMF) model is also experimenting with some promising techniques using that model. Models like the GloSea and ECMWF will only get better as increased computer power and better understanding of the atmosphere are incorporated, necessitating less use of "fudge" factors based on historical hurricane patterns. If human-caused climate change amplifies in coming decades, statistical seasonal hurricane forecasts like the CSU's may be limited in how much they can be improved, since the atmosphere may move into new patterns very unlike what we've seen in the past 100 years. It is my expectation that ten years from now, seasonal hurricane forecasts based on global computer models such as the UK Met Office's GloSea will regularly out-perform the statistical forecasts issued by CSU.

2010 Atlantic hurricane season forecast from Florida State University
Last year, another group using dynamical computer forecast models entered the seasonal hurricane prediction fray. A group at Florida State University led by Dr. Tim LaRow introduced a new model called COAPS, which is funded by a 5-year, $6.2 million grant from NOAA. This year, the COAPS model is calling for 17 named storms and 10 hurricanes. Last year's prediction by the COAPS model was for 8 named storms and 4 hurricanes, which was very close to the observed 9 named storms and 3 hurricanes.

Summary of 2010 Atlantic hurricane season forecasts
Here are the number of named storms, hurricanes, and intense hurricanes predicted by the various forecasters:

23 named storms: PSU statistical model
20 named storms: UKMET GloSea dynamical model
18.5 named storms, 11 hurricanes, 5 major hurricanes: NOAA hybrid statistical/dynamical model technique
18 named storms, 10 hurricanes, 5 intense hurricanes: CSU statistical model (Phil Klotzbach/Bill Gray)
17.7 named storms, 9.5 hurricanes, 4.4 intense hurricanes: Tropical Storm Risk (TSR), hybrid statistical/dynamical model technique
17 named storms, 10 hurricanes: FSU dynamical model
10 named storms, 6 hurricanes, 2 intense hurricanes: climatology

Only four hurricane seasons since 1851 have had as many as nineteen named storms, so 5 out of 6 of these pre-season forecasts are calling for a top-five busiest season in history. One thing is for sure, though--this year won't be able to compete with the Hurricane Season of 2005 for early season activity--that year already had five named storm by this point in the season, including two major hurricanes (Dennis and Emily.)

Tropical Storm Conson threatens the Philippines
Weather456 has an interesting post on why the Western Pacific typhoon season has been exceptionally inactive this year. It looks like we'll have out first typhoon of the Western Pacific season later today, since Tropical Storm Conson appears poised to undergo rapid intensification, and should strike the main Philippine island of Luzon as a Category 1 or 2 typhoon.

Next post
I'll have an update Wednesday.

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: 1464 - 1414

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61Blog Index

Morning all, They have the cap on. For some reason they pulled the pipe off the top of the cap.
Member Since: Posts: Comments:
1463. aquak9
Quoting weathermanwannabe:


You have a point; either re-runs, or, they ran into a techincal glitch and removed it overnight (under cover of darkness while we slept)......


well the ROV's have floodlights everywhere, it's always dark down there, hahaha. But yeah, unless they pulled the cap back off, it still spews.

They gotta be so careful at this point- if pressures rise to quickly, if the lower part of the BOP is damaged, if there's casing damage under the seabed floor...
Member Since: Posts: Comments:
Quoting stormhank:
Could u guys talk me thru the quote button feature...Ive tried it sevferal times n it doesnt work for me..
Sometimes u have to press the quote, then go back to the message after page refresh and press quote again. [also true of the modify button.] Once u get the quote in the comment window, be sure to go to the very end of the quote [after the little > sign] before you start typing.
Member Since: Posts: Comments:
Quoting weathermanwannabe:


You have a point; either re-runs, or, they ran into a techincal glitch and removed it overnight (under cover of darkness while we slept)......


The new cap is in place; today BP will attempt to connect and test the apparatus that will, it is hoped, allow most/all of the belching crude to be collected.
Member Since: Posts: Comments:
1459. IKE
Quoting SpicyAngel1072:



nada...


Nada? It shows a 1030 mb high building back in in day 7, 168 hours....Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
lots of downcasting this morning I see. With the high pressures and SAL I can see why! So much for the very active hurricane season. Not going to happen folks. Above average maybe but not by much. Done watching the tropics for couple of weeks.
Member Since: Posts: Comments:
Quoting IKE:


00Z run...



nada...
Member Since: Posts: Comments:
Quoting IKE:
I'm convinced, this may go on for awhile....

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT TUE JUL 13 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER ROBERTS/BROWN


Morning Ike,I'm jumping on your bandwagon. I just hope we don't pay for this come aug thru nov. fingers crossed
Member Since: Posts: Comments:
Mornin Storm W.
Member Since: Posts: Comments:
Quoting aquak9:


re- the cap


err. i just looked at the cams. Unless they're broadcasting re-runs, the spew still spews. I didn't see no stinkin' cap.


You have a point; either re-runs, or, they ran into a techincal glitch and removed it overnight (under cover of darkness while we slept)......
Member Since: August 8, 2006 Posts: 0 Comments: 8311
1453. IKE
Quoting StormW:


IKE,
Which ECMWF are ya lookin' at?


00Z run...
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1451. aquak9
Quoting IKE:


They're running tests starting this morning.


re- the cap


err. i just looked at the cams. Unless they're broadcasting re-runs, the spew still spews. I didn't see no stinkin' cap.
Member Since: Posts: Comments:
Quoting portcharlotte:
Need to pay attention to the Bahamas

From the Mia Discussion

A SHEAR AXIS EXTENDING ACROSS THE SE BAHAMAS EXTENDING TO THE
NORTHEAST CONTINUES TO RESULT IN CONVECTION THERE. ROTATION IS
SEEN IN LOW LEVEL CLOUDINESS JUST EAST OF THE BAHAMAS AND CIMMS
SHOWS AN 850 MB VORT BULLSEYE THERE. ALSO...HIGHER MOISTURE IS
ENTRENCHED ACROSS THE BAHAMAS. GFS/ECWMF/NAM BRING THIS FEATURE
AS AN INVERTED TROUGH ACROSS THE AREA ON WEDNESDAY...WHICH WILL
INCREASE THE CHANCE OF SHRA/TSTORMS ACROSS SOUTH FL...ESPECIALLY
SOUTHERN SECTIONS WHERE MOISTURE WILL BE GREATEST

After it crosses FL and gets into the Gulf if another front does not kick it back across would be it's best chance..
Member Since: Posts: Comments:
Quoting stormhank:
Could u guys talk me thru the quote button feature...Ive tried it sevferal times n it doesnt work for me..


You might have to hit the button once or twice; you know it worked when the quote you want actually appears in your comment box. Then, you can type your own comment underneath...Keep clicking the quote button until the one you want "appears" in your comment box.....
Member Since: August 8, 2006 Posts: 0 Comments: 8311
Quoting SWFLgazer:
If Michael Mann were to tell me that the Sun rises in the East, I'd have to check it out. Fool me once, shame on you. Fool me twice, shame on me.


Why's that? A deep, thorough investigation cleared Mann of any wrongdoing in the 'Climategate' 'scandal'.
Member Since: Posts: Comments:
Quoting IKE:
"AccuWeather.com's Bastardi Revises Forecast

* On June 21, Joe Bastardi, Chief Hurricane Meteorologist for AccuWeather.com, revised his earlier forecast to predict that 18 to 21 named storms will occur in the 2010 hurricane season, four of which are expected to occur during July. The revised forecast expects five or six of the named storms to be hurricanes. http://www.accuweather.com/blogs/news/story/33013/bastardi-ups-hurricane-season.asp12 Bastardi's original forecast called for 16 to 18 names storms."........


Good luck reaching 4 Joe....*heads for coffee refill.*


Hey Now; conditions could change, the "switch" can be thrown, and, we could have a cluster of three storms the last week of July.......... :)
Member Since: August 8, 2006 Posts: 0 Comments: 8311
Could u guys talk me thru the quote button feature...Ive tried it sevferal times n it doesnt work for me..
Member Since: Posts: Comments:
1444. IKE
Quoting IKE:
One thing I noticed on the operational GFS 6Z run...the high in the central-Atlantic is weakening now...but in a few days is forecast to strengthen again. GFS gets it back up to 1031 mb's in about a week. Maybe more SAL moving off Africa.


Parallel GFS and ECMWF do the same as the GFS.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1443. IKE
"AccuWeather.com's Bastardi Revises Forecast

* On June 21, Joe Bastardi, Chief Hurricane Meteorologist for AccuWeather.com, revised his earlier forecast to predict that 18 to 21 named storms will occur in the 2010 hurricane season, four of which are expected to occur during July. The revised forecast expects five or six of the named storms to be hurricanes. http://www.accuweather.com/blogs/news/story/33013/bastardi-ups-hurricane-season.asp12 Bastardi's original forecast called for 16 to 18 names storms."........


Good luck reaching 4 Joe....*heads for coffee refill.*
Member Since: June 9, 2005 Posts: 23 Comments: 37858
SAL SAL always SAL. Well have a nice (hazy) day ^^
Member Since: Posts: Comments:
Good Morning. Atlantic calm this AM and lots of energy in the E-Pac. While Alex formed when the E-Pac was also very active, against conventional wisdom so to speak if you follow the "inverse" relationship between the two basins, it still formed in the same general region (SW Atl-Central America-E-Pac). Given current conditions in the E-Pac, things should probably remain quiet on the Atlantic side for at least a week IMHO.
Member Since: August 8, 2006 Posts: 0 Comments: 8311
1440. IKE
I'm convinced, this may go on for awhile....

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT TUE JUL 13 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER ROBERTS/BROWN

Member Since: June 9, 2005 Posts: 23 Comments: 37858
1439. IKE
One thing I noticed on the operational GFS 6Z run...the high in the central-Atlantic is weakening now...but in a few days is forecast to strengthen again. GFS gets it back up to 1031 mb's in about a week. Maybe more SAL moving off Africa.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Greetings and salutations..
Member Since: July 1, 2005 Posts: 10 Comments: 1681
Quoting stormhank:
maybe it will bruce, stay quiet,,,but I fear next 3 months will probably not be so quiet


Im with you on both accounts!
Member Since: July 1, 2005 Posts: 10 Comments: 1681
1436. IKE
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE JUL 13 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1000 UTC...

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 18N31W TO 6N29W MOVING W 15-20 KT.
THE WAVE LIES AHEAD OF A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT
IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD CYCLONIC FLOW IS ALSO
ABOUT THE WAVE AXIS EVIDENT IN IN THE FIRST VISIBLE SATELLITE
IMAGES OF THE DAY. THESE IMAGES ALSO INDICATE AN AREA OF DUST
ASSOCIATED WITH A DRY SAHARAN AIR LAYER IS ACROSS MUCH OF THE
TROPICAL ATLC SUPPRESSING CONVECTION NEAR THE WAVE.
HOWEVER...SCATTERED MODERATE/STRONG CONVECTION IS NEAR THE ITCZ
FROM 8N-11N BETWEEN 28W-35W.

TROPICAL WAVE IS ALONG 51W/52W S OF 16N MOVING W 15-20 KT. WAVE
IS SUPPRESSED AND MASKED DUE TO A DRY SAHARAN AIR LAYER ACROSS
THE TROPICAL ATLC KEEPING CONVECTION TO A MINIMUM AND RESTRICTED
TO THE ITCZ.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 7N-11N BETWEEN 49W-54W.

TROPICAL WAVE IS ACROSS THE YUCATAN PENINSULA INTO THE E PACIFIC
EXTENDING FROM 19N88W TO 8N90W MOVING W NEAR 20 KT. MOISTURE
ASSOCIATED WITH THIS WAVE HAS NOW MOVED MOSTLY OUT OF THE WRN
CARIBBEAN. THE WAVE ALSO LIES AHEAD OF A DRY SAHARAN AIR LAYER
AND A LARGE AREA OF DUST ACROSS THE TROPICAL ATLC AND ACROSS THE
CARIBBEAN.
DUE TO A DIFFLUENT ZONE ALOFT SCATTERED
MODERATE/STRONG CONVECTION IS ACROSS GUATEMALA/YUCATAN PENINSULA
S OF 17N BETWEEN 88W-93W.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1435. WxLogic
Good Morning...

All calm so far...
Member Since: Posts: Comments:
maybe it will bruce, stay quiet,,,but I fear next 3 months will probably not be so quiet
Member Since: Posts: Comments:
So far, so good as the hurricane season continues to be quiet (knock on wood). I hope the relative lack of activity continues although it's still very early.

The t-wave set to exit Africa is pretty far to the north fortunately, almost around 15N, so if tried to develop, it would probably be pulled northward at some point before it got too far west.
Member Since: Posts: Comments:
Well, I gotta dash. I'll try to look in later if time permits.
Member Since: Posts: Comments:
One thing that is difficult to predict is the SAL. I believe that early season predictions did not account for the strength of the SAL this season. I don't believe we will have half the storms everyone is predicting as the SAL will choke development. Looks like 2010 will be an overhyped dud of a season!!
Member Since: Posts: Comments:
I think we'll get the numbers. I'm surprised we actually have a hurricane already in the "count", considering what June / July usually are like. I wouldn't be surprised to see something form between 21 - 31 July, though I'm hoping nothing happens. But with la nina the seasonal activity often continues into Nov, so we may still be seeing a storm or 2 then....
Member Since: Posts: Comments:
I wonder if those high numbers predicted will actually pan out?? im goin with 16. 8, 4 of course i could be eating crow also lol
Member Since: Posts: Comments:
Quoting stormhank:
I wander Baha..if that dust will keep Cape Verde area quiet from tropical develepement for a while??
That's was I was thinking. With that particular EUMETSAT product, the darker the pink, the heavier the dust.
Member Since: Posts: Comments:
I wander Baha..if that dust will keep Cape Verde area quiet from tropical develepement for a while??
Member Since: Posts: Comments:
1426. IKE
All Quiet in the Atlantic
Jul 13, 2010 6:55 AM


Currently there are no organized tropical systems and we do not anticipate any development into late week. The tropical Atlantic features 3 definable tropical waves, two of which contain a good deal of Saharan dust entrainment. The dry, dusty air stretches from a good chunk of the Atlantic into the eastern half of the Caribbean. This is in tern suppressing thunderstorm development from the eastern Caribbean on east. This in combination with a broad high level trough over the western Atlantic into the Bahamas is exerting strong shear across parts of the southwest and south central South Atlantic. This will continue to pull any thunderstorms that develop away from any low level circulations. Computer guidance continues to show a quiet week in the Atlantic Basin.

By Meteorologist Justin Povicki
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1419. stormhank.

I haven't looked at the oilspill feeds as yet....
Member Since: Posts: Comments:
A heck of a dust storm seems to be blowing across southern Algeria / northern Mali.... look at how deep the magentas are flowing west from there..... all this is prolly what the GFS is responding to when keeping system development at a minimum...

Member Since: Posts: Comments:
Maybe tropics will saty quiet thru July...Not going to say that about Aug. and Sept though
Member Since: Posts: Comments:
Quoting stormhank:
Hi btwn.. I havent seen much on the models yet..of course they all change run to run


...which is precisely why folks shouldn't get all worked up one way or another when those models show—or don't show—things happening...especially at very long time frames.
Member Since: Posts: Comments:
1421. IKE
Quoting stormhank:
Morning baha n Ike!!! any word on if that oil cap worked ??


They're running tests starting this morning.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
NEXT!!!

Member Since: Posts: Comments:
Morning baha n Ike!!! any word on if that oil cap worked ??
Member Since: Posts: Comments:
1418. IKE
No one can come on here and accuse the GFS of spinning up spurious lows because the 6Z GFS spins up virtually no lows through July 29th.

Parallel GFS takes a system over the Yucatan peninsula in 7-8 days. Looks like a TD or weak TS.

Neither model shows any USA threats through July 29th.

I see the 00Z CMC has dropped the spurious Caribbean low...Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Guess Im the early riser this morning lol...anyone out there in chat land????
Member Since: Posts: Comments:
Morning all.

Just looking in for a few minutes. I actually saw the sunrise today... only partly cloudy for a while.
Member Since: Posts: Comments:
Hi btwn.. I havent seen much on the models yet..of course they all change run to run
Member Since: Posts: Comments:

Viewing: 1464 - 1414

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61Blog 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.