91L no concern; more postcards from the AMS hurricane conference
I'm in Ponte Vedra Beach, Florida this week, where the world's hurricane experts are gathered to attend the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society. Most of the Hurricane Specialists from the National Hurricane Center are here, and they are keeping an eye on the waters a few hundred miles east of Bermuda, where an extratropical storm has cut off from the jet stream and is slowly acquiring tropical characteristics. This system was designated Invest 91L last night by NHC. Ocean temperatures are around 20°C (68°F) in the region, which is well below the 26°C usually needed for a tropical storm to form. Wind shear is a high 20 - 30 knots. Nevertheless, 91L has managed to develop a small amount of heavy thunderstorm activity near its center, and may continue to show more organization as it moves slowly southeastward over the next day or two. I give 91L a close to 0% chance of becoming a named storm in the next two days, and NHC seems to have stopped issuing new products for the system. By the end of the week, 91L should get picked up by a trough of low pressure and move off to the northeast. The storm is not a threat to any land areas.

Figure 1. Morning satellite image of Invest 91L. The island of Bermuda is seen at the left side of the image.
Global tropical cyclones and climate: current signal
Now, I'll summarize a few of the excellent talks given at this week's AMS hurricane conference. Dr. Greg Holland of the National Center for Atmospheric Research talked about the impact of global warming on hurricane intensities. Using data beginning in 1975, the beginning of the satellite era, he showed that while the total number of hurricanes globally has decreased in recent years, the proportion of hurricanes that are of Category 4 - 5 intensity has increased by 40%. He showed that this change could be related to a 0.8°C increase in global temperature during the period. He concluded that when hurricanes form, they are finding that it is easier for them to reach higher intensities.
Sensitivity of the strongest hurricanes to ocean surface warmth
Dr. Jim Elsner of Florida State University showed that observations indicate a sensitivity of hurricane winds of 8.2 m/s +/- 1.19 per degree Centigrade of ocean warmth, using data in the Atlantic from 1981 - 2010 (for oceans areas warmer than 25°C.) Using a high resolution model (HiRAM) with 50 km resolution, a sensitivity of only 1.5 +/- .6 m/s was found, calling into question the usefulness of current models for assessing future hurricane activity.
How will climate change affect hurricane tracks?
Angela Colbert of the University of Miami used 17 global climate models, the BAM hurricane tracking model, and the Atlantic historical HURDAT data base to see how hurricane tracks might change in the future. She classified storms as either straight moving (which tend to hit the Caribbean or U.S. Gulf Coast), recurving landfalling (U.S. East Coast impacts), or recurving ocean storms that miss landfall. She projected a 6% increase in recurving ocean storms and an 8% decrease in straight-moving storms by the end of the century, due to climate change. A decrease of 1- 2 storms per decade is predicted for the Caribbean and Gulf of Mexico, and an increase of 1 - 2 storms per decade in the waters of the mid-Atlantic, and along the East Coast of Florida. This occurs primarily because of an increase in westerly winds over the Central Atlantic, and to a lesser degree, an eastward change in genesis location closer to the coast of Africa. Both of these factors would tend to increase the number of recurving storms.
Jeff Masters
Reader Comments
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LOL. I mean, seriously.
Can you imagine? Some crackhead is going to google "acid, crack, marijuana, drugs" and the first result is going to be "Dr. Jeff Masters' WunderBlog: 91L no concern..."
I appreciate your encouragement but most of south TX precip from El-Nino comes from a combination of E-Pac tropical storms & the subtropical west to east jet. Both need to be in place. The subtropical jet tends to be active when the monsoon trough (Intertropical Convergence Zone) is retreating southward. Which is in the fall.
I just don't see an increase in westerly winds from the tropical E-Pac as summer approaches. I wish, but it isn't likely :(
edit: the link is just a little sampling of the many flavors.. not a comprehensive source, fyi.
000
FXUS62 KKEY 181846
AFDKEY
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
250 PM EDT WED APR 18 2012
.DISCUSSION...
.CURRENTLY...
KBYX DETECTS NO PRECIPITATION ECHOES IN THE FORECAST AREA. SKIES
OVER THE ISLAND CHAIN ARE VARIABLY CLOUDY. WINDS OVER LAND ARE
SOUTHEAST TO SOUTH NEAR 10 MPH. C-MAN WINDS...ON AVERAGE...ARE
SOUTHEAST TO SOUTH AT 10 TO 15 KNOTS. TEMPERATURES ARE IN THE LOWER
80S.
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
AN AREA OF HIGH PRESSURE JUST NORTH OF THE BAHAMAS WILL MOVE TO THE
NORTHEAST TONIGHT THROUGH FRIDAY NIGHT. DESPITE ADEQUATE MOISTURE
AND INSTABILITY IN PLACE TO GENERATE SHOWERS...LACK OF AN APPARENT
CONVECTIVE TRIGGER SHOULD LIMIT MEASURABLE RAIN CHANCES TO LESS THAN
10 PERCENT FOR THE FLORIDA KEYS TONIGHT. ISENTROPIC ASCENT IS LIKELY
THURSDAY THROUGH FRIDAY WELL SOUTH OF A DECAYING TROUGH OF LOW
PRESSURE OVER THE FLORIDA PENINSULA. BE THAT AS IT MAY...SLIGHT
CHANCE POPS SHOULD SUFFICE THURSDAY THROUGH FRIDAY. BY FRIDAY
NIGHT...THERE SHOULD BE ENOUGH ATMOSPHERIC INSTABILITY AND MOISTURE
TO SUPPORT THUNDERSTORM FORMATION ALONG ANY POTENTIAL LAND BREEZE
THAT PEELS OFF THE NORTH COAST OF CUBA.
.LONG TERM (SATURDAY THROUGH WEDNESDAY)...
A STRENGTHENING AREA OF LOW PRESSURE WILL PROGRESS EASTWARD ACROSS
THE NORTHERN GULF COAST SATURDAY AND SATURDAY NIGHT. THE TRAILING
TROUGH ASSOCIATED WITH THIS AREA OF LOW PRESSURE SHOULD PASS THROUGH
THE FLORIDA KEYS SUNDAY. RAIN CHANCES WILL STEADILY INCREASE
SATURDAY AND SATURDAY NIGHT. STRONG THUNDERSTORMS ARE A DISTINCT
POSSIBILITY SUNDAY. IN WAKE OF THE AFOREMENTIONED TROUGH OF LOW
PRESSURE...RAIN CHANCES WILL TREND BACK TO NORMAL VALUES EARLY NEXT
WEEK.
&&
.MARINE...
GENTLE TO MODERATE SOUTHEAST TO SOUTH BREEZES WILL PREVAIL ON ALL
KEYS COASTAL WATERS TONIGHT. NO ADVISORIES OR CAUTIONARY HEADLINES
EXPECTED TONIGHT THROUGH AT LEAST SATURDAY. A SMALL CRAFT ADVISORY
MAY BE REQUIRED FOR ALL KEYS COASTAL WATERS SATURDAY NIGHT. A SMALL
CRAFT ADVISORY WILL LIKELY BE REQUIRED FOR ALL KEYS COASTAL WATERS
SUNDAY AND SUNDAY NIGHT. A SMALL CRAFT ADVISORY MAY BE REQUIRED FOR
ALL KEYS COASTAL WATERS MONDAY. SUSTAINED NORTHWEST SURFACE WINDS OF
15 TO 20 KNOTS ARE POSSIBLE ON ALL KEYS COASTAL WATERS MONDAY NIGHT.
&&
.AVIATION...
VFR CONDITIONS SHOULD PERSIST AT THE ISLAND TERMINALS OF EYW AND MTH
THROUGH THE PERIOD. MVFR CIGS MAY BE POSSIBLE AGAIN TONIGHT.
SOUTHEAST BREEZES SHOULD PERSIST THROUGH THE PERIOD.
&&
.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1953...THE HIGH
TEMPERATURE IN KEY WEST WAS 88 DEGREES. THIS SET THE DAILY RECORD
FOR MAXIMUM TEMPERATURE MEASURED IN KEY WEST ON APRIL 18TH...A
RECORD WHICH STILL STANDS 59 YEARS LATER. TEMPERATURE RECORDS AT KEY
WEST DATE BACK TO 1872.
&&
.PRELIMINARY POINT TEMPS/POPS...
KEY WEST 75 84 74 84 / 05 10 20 20
MARATHON 75 86 74 86 / 05 10 20 20
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE/FIRE/CLIMATE/DIGITAL...BS
AVIATION/NOWCASTS....................MSB
DATA ACQUISITION.....................ULRICH
VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST
Its a pity there is no way to pulse a whole page of the blog, cos this last page I have copied and pasted and sent via e-mails to several people to demonstrate,via the http. of these pages to demonstrate, what can be achieved by people who in the main don't even know each other but somehow KNOW each other!
Oh yeah, can't complain about it at all. You walk outside at midday and it feels great.
A Coke?
Well what do you expect on here?
Normal People?
You obviously lack basic observation skills. ;)
It's getting humid up here and cloudy. Looks as if some rain is pushing up into the FL Big Bend and is supposed to get here maybe later tonight.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
257 PM AST WED APR 18 2012
.SYNOPSIS...AT UPPER LEVELS...A SHORT WAVE TROUGH WILL MOVE
THROUGH TONIGHT AND THE CORE OF AN 80 KNOT JET WILL CROSS THROUGH
THE AREA...FOLLOWED QUICKLY BY A SHORT WAVE RIDGE ON THURSDAY
EVENING. A WEAK TROUGH WITH A JET CORE WILL PASS THROUGH ON
SATURDAY MORNING FOLLOWED BY A WIDE AND RELATIVELY STRONG RIDGE
PASSING THROUGH ON SUNDAY EVENING. A STRONG TROUGH WILL DIG INTO
THE WESTERN CARIBBEAN LATE NEXT WEEK.
AT MID LEVELS...WEAK TROUGHING CONTINUES IN THE AREA UNTIL THE
WEEKEND. A RIDGE WILL FOLLOW THAT WILL CONTINUE INTO MONDAY OF
NEXT WEEK AND THEN EDGE INTO THE WESTERN TROPICAL ATLANTIC DURING
THE REST OF THE WEEK. MOISTURE INCREASES...BEGINNING FRIDAY AND
PEAKING AROUND MID WEEK...BUT STAYS MAINLY OVER THE DOMINICAN
REPUBLIC.
AT LOWER LEVELS...DRY AIR OVER THE WESTERN ATLANTIC ASSOCIATED
WITH A WEAK HIGH PRESSURE WILL MOVE EAST. MOISTURE WILL BEGIN TO
INCREASE ON FRIDAY. MOISTURE FROM SOUTH AMERICA WILL MERGE WITH
MOISTURE IN A EASTWARD MOVING CONVERGENCE ZONE BEGINNING TUESDAY
AND CONTINUING THROUGH THE END OF THE WEEK.
&&
.DISCUSSION...SHOWERS HAVE JUST BEGUN TO FORM IN PARTLY CLOUDY
SKIES THIS AFTERNOON. INTENSE HEATING HAS GENERATED REPORTS OF FIRES IN
MAYAGUEZ AND WHIRLWINDS IN GUAYAMA. FIRES MAY HAVE ALSO BEEN SEEN
IN SALINAS IN SATELLITE IMAGERY. WITH MODEST EAST NORTHEAST
FLOW...SEA BREEZES HAVE BEEN PREDOMINANT OVER MOST COASTAL AREAS.
DRY AIR WILL CONTINUE OVER THE AREA UNTIL FRIDAY WHEN MOISTURE
RETURNS FROM THE SOUTHEAST. FROM FRIDAY TO TUESDAY FLOW CONTINUES
TO HAVE A SOUTHERLY COMPONENT THAT BRINGS INCREASING MOISTURE AND
SHOWERS IN FROM THE SOUTHEAST. AS MOISTURE FILLS IN AT MID AND
UPPER LEVELS SHOWERS WILL BECOME MORE WIDESPREAD AND
STRONGER...ESPECIALLY IN THE WEST AND NORTHWEST PARTS OF PUERTO
RICO DURING THE WEEK NEXT WEEK. AT PRESENT IT LOOKS LIKE MOST OF NEXT
WEEK WILL BE SHOWERY. WITH BETTER DIURNAL HEATING...EXPECT A
GREATER FREQUENCY OF THUNDERSTORMS AS WELL. IT IS TOO EARLY TO SAY
MUCH ABOUT POSSIBLE FLOODING...BUT EXPECT THE BEST MOISTURE TO BE
OVER THE DOMINICAN REPUBLIC RATHER THAN PUERTO RICO OR THE U.S.
VIRGIN ISLANDS.
&&
.AVIATION...VERY BRIEF MVFR CONDITIONS WILL REMAIN POSSIBLE THROUGH
ABOUT 18/22Z OVER SOUTHWEST PUERTO RICO INCLUDING THE VICINITY OF
TJMZ AND TJPS DUE TO ISOLATED TO LOCALLY SCATTERED SHOWERS.ELSEWHERE...
VFR CONDITIONS EXPECTED NEXT 24 HOURS. LOW LEVEL WINDS FROM THE EAST
NORTHEAST AT 10 TO 15 KT.
&&
.MARINE...WINDS AND SEAS WILL DIMINISH...ALTHOUGH WINDS REMAIN
ABOVE 15 KNOTS IN THE SOUTHERN-MOST WATERS SOUTH OF PUERTO RICO
UNTIL FRIDAY. SEAS INCREASE SUNDAY INTO MONDAY BUT SMALL CRAFT
ADVISORIES ARE NOT EXPECTED DURING THE NEXT 7 DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 74 85 / 0 0 10 10
STT 72 84 74 86 / 0 0 10 10
witness my english major in action!!
(capitalize.. what's That mean??)
Dick Clark Dies: TV Legend Dead At 82
No, not yet but I'll give it a try.
Tuscaloosa, AL:
North Carolina-South Carolina State Line Redrawn
Just a note Press but you could be in a very significant Area:-
The Plains of Nazca Etc.
http://www.google.co.uk/search?q=the+plains+of+na zca&hl=en&safe=off&qscrl=1&nord=1&rlz=1T4ADRA_enES 400ES400&prmd=imvns&tbm=isch&tbo=u&source=univ&sa= X&ei=ox6PT5CWGuKn0QW-y5HiAQ&sqi=2&ved=0CC4QsAQ&biw =1304&bih=605
Carolina's. LOL;)
Does wishing that I lived in Hawaii count?
Good afternoon to you. How is the weather in Jamaica? Here we are in a few dry days,but things will once again turn wet by the weekend. Temperature in San Juan was 81F as of 4 PM AST.
I don't know whether we should take this seriously but is there a possibility that this might lead to civil war? I mean with all these problems in the Middle East, over boarders, missile attacks, UN sanctions, NATO involvement etc?
Or is it just one of those boundary disputes that sells a lot of newspapers?
Yep
That might be what we're getting tomorrow here. It's been so nice but I can take a rainy day.
I had heard the local Tuscaloosa paper won the Pulitzer for their reporting. It may be worth checking for the weather history buffs.
I'm good...today is dry, but it has been generally wet here in Jamaica
I always have some when I have headaches and it works wonders. Hopefully it'll do the same for you.
Depends on if China vetoes it in the Security Council or not...
Was it Wolf who got involved in Quebec? What about that tea party in Boston? ( probably to do with rip off taxes?)
What about those islands in the South Atlantic? Falklands/Malvina's! Etc. Etc.
I once tried to import a parrot across a European boarder; the customs official said why are you declaring it? Those things fly over here all the time! "Ive never seen one with a passport before!"
Albany, New York:
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND.... QPF AMOUNTS ARE HIGHLY IN QUESTION. AT THIS TIME...LOOKING AT SIGNIFICANT MULTI-DAY RAINFALL EVENT WITH
POTENTIALLY UP TO 5 INCHES OCCURRING. PRECIPITATION SO FAR THIS YEAR
IS ABOUT HALF OF WHAT IT SHOULD BE. PRECIPITATION ACROSS THE AREA IS
RUNNING AROUND 5 TO 6 INCHES BELOW NORMAL.
Should be enough to just about end this drought in the northeast.
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