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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This might be more SEVERE than many think in FLORDA as the SYSTEM which could become a SURFACE LOW with some TROPICAL Characters as it moves across the GULF OF MEXICO.
If the blindness mutations are not stopped it will permanently destroy the population.
If neither predator nor prey are being selected based on vision, perhaps due to black oil and other filth in the water, then there is reinforcement of the otherwise negative trait produced by the mutation.
This is similar to what happens to cave fish and such in genetically isolated populations in total darkness, except here it's happening at a ridiculously accelerated pace.
We will need to be breeding healthy organisms in tanks to preserve a healthy gene pool.
In the future, when the pollution goes away, we will need to hunt the mutated strains to extinction, and then re-introduce the healthy ones back to the population.
An even bigger problem is what to do about the mutated microbes?
Any mutagen powerful enough to do this to macroscopic organisms within a few generations could no doubt cause insane changes to bacteria, algae, diatoms, viruses, and other such creatures.
90s are also used for the Southern Hemisphere. The letters behind the number change per the area.
Depending on the agency:
NHC
01 - 30
"numbered storms with forecasts issued and numbers are *not* recycled until the next season."
90 - 99 "Invest, areas of interest watched by forecasters for possible development and these numbers are re-used periodically throughout the
season"
80 - 89 "Internal training storm numbers which are to always be ignored"
Link
NAVY
01 to 49 are real storms, 80 to 89 are test storms, 90 to 99 are INVESTS
Link
Brian
33 MontanaZephyr: Gulf seafood deformities alarm scientists
Yep, that's what the NWS offices around FL are saying. I think this is where the concern is coming from as were getting a winter type storm diving and developing over the Gulf in late April where the Gulf temps are near 80. People on the blog will take notice on Friday I can betcha if this trend continues. This Gulf system could put 91L to shame organization wise come Saturday.
WATERS are too COLD for much to develop in that location!
313 hydrus: It is hard for me to imagine a wind gust of 253 mph.
Try roof-surfing on a BugattiVeyron running at top speed.
Lol, I know... Still fun to watch an invest in April though.
Atlantic
AL912012 - INVEST
Enhanced Infrared (IR) Imagery (4 km Mercator)
Boy do I love seeing all that green over MA... We really need it
Is this Joe Bastardi trying to solicit Doc's members?
Not looking good out there, still can get major rain events into May, It's about that time TX is gonna get a tropical storm in June, that may be the missing link needed
One of our mets did mention "possible tropical stuff heading our way".
Sorry, 80's are test numbers....
Never take one source on the NET as Gospel !
Friday will be transitional day across the area...as a strong long
wave trough begins to rapidly deepen over the plains states.
Increasing southerly flow will develop in advance of this trough
across the forecast. Expect strong low level moisture advection to
develop by Friday afternoon...with deeper moisture moving in by
Friday night. With this increase in moisture...additional
increasing cloud cover can also be expected by Friday evening.
Overnight lows will also be higher...with readings only cooling
into the lower to middle 60s across the region.
By late Friday night...a closed low will begin to form at the base of the long wave trough axis. The low will be fairly vertically stacked...with surface low in nearly the same position as the middle to upper level
low. The closed low will descend south and east...and will transit over the forecast area this coming weekend.
A cold front is
expected to develop at the base of the surface low over the
Southern Plains Friday night. As this front develops...a line
of convection may develop along the front and race into the
forecast area by late Friday night. Although the severe threat is
low...there could be an isolated stronger thunderstorm embedded
within the line of convection. Have went with chance probability of precipitation for the
area late Friday night to reflect the expected line of convection.
Thanks for the kindness and taking the time.
I default to posting the actually url text so that people can directly see the ID and domain of the site that they would be going to.
It seems more the civic thing to do with a relatively educated and sophisticated group, the members of which will generally think it no trouble to copy/paste. On more common sites, a clickable link is customary, but that can lead to hidden spams and viruses and so on.
Group: Please advise as to what is preferred.
Thanks.
No the trough is still in Montana.
as here: North American Surface Analysis
One can then decide to go there or not.
wunderground.com did that about 2 years ago after some viruses were embedded here that caused a lil temp grief.
you can find all the models at my site...but here you go...click the graphic below.
It is a great blog with lots of many different personalities:)
Now in the water on this 12z run.
The long range CPC forecasts are not binary, and as such, you cannot have "the complete opposite of what was forecasted." The forecasts are probabilistic in nature, and generally show the probability of three choices... above normal, below normal, equal chances. An area indicated as "above normal" with a 50% contour does not mean a forecast of above normal; it means there is a 50% chance of above normal with a 50% chance of normal or below normal.
A 60% contour must be forecasted before you really even reach a true forecast for either below/above to be the most likely scenario.
Hermine was a perfect event, S TX gets it, and South Central/Hill country gets it, even SE TX got in the action with a large feeder band from Hermine. Overall perfect path, size, and event for TX.
Excerpt:
The Commerce, Justice, Science and Related Agencies Subcommittee of the Senate Appropriations Committee today approved a fiscal year 2013 appropriations bill that would shift responsibility for building four major satellite systems from the National Oceanic and Atmospheric Administration (NOAA) to NASA. The move—which would need approval from the full Senate, the U.S. House of Representatives and the White House to become reality—marks the latest twist in a long and contentious debate over how to sustain an expensive and delay-prone satellite fleet.
Also:
Bill Markup Summary (PDF)
Excerpt:
National Oceanic and Atmospheric Administration (NOAA) – The bill provides $3.4 billion for NOAA, which is $1.47 billion below the fiscal year 2012 enacted level. The bill does not support proposed cuts to NOAA’s operations that would hurt local communities, such as eliminating local weather forecasting staff and reducing the U.S. Tsunami Warning Network. Instead, the committee finds financial savings by consolidating management offices and reducing government overhead. The bill transfers funding needed for weather satellite acquisition from NOAA to NASA, resulting in a savings of $117 million in fiscal year 2013.
Hi Pat, The 12Z GFS has this low just to your south at 1000 milibars. It also shows heavy rain banding into your location Saturday with maybe some strong winds.
No it isn't. I think the Loop Current is further north right now. I'll check that. Thanks man!
Link
This will NOT be Alberto. It will be a cold core system when it develops and will not have enough time over the warm Gulf to transition into anything warm core. It won't even have enough time to take on Sub-tropical characteristics. It will most likely create a solid line of convection in the warm sector of the storm with overunning rain north of the warm front. Still some questions on where that sets up, but this will not be tropical at all.
Should be nice to observe as it evolves.
What exactly is the explanation of why global warming should increase westerlies?
This is the way I see this situation.
If the greenhouse effect works the way it has been described, by trapping heat globally, and of course bringing the planet closer and closer to equilibrium by distributing much of the excess heat to the polar regions, then why would westerly winds in the steering layers or the surface increase?
If the difference in temperature between different latitudes and longitudes decreases due to a thermal blanket effect, then that should decrease the maximum thermodynamic potential between any two points at the same elevation, which should in turn decrease maximum potential non-tropical winds.
This is not to be confused with potential tropical cyclone winds, because tropical cyclones are powered by differences in temperature vertically, while westerlies are powered by horizontal differences in temperature.
If the temperature of the poles will be increasing faster than the temperature at the equator and mid-latitudes; for example, the pole increases by 6C and the equator increases by like 1C, then the difference between the two is reduced by 5C, but average global temperature might be just 2C or 3C warmer than today by then. That means a lower thermodynamic potential between the equator and the poles. This should translate into weaker troughs, which will fail to pick up hurricanes, and therefore fail to pull them northwards.
Combining both of these effects, then this should translate to stronger, slower moving, persistent hurricanes which track more west.
Now that's my highly intuitive understanding based on thermodynamics 101.
If anyone cares to explain why I'm wrong, I'm willing to be "educated".
I think what RitaEvac meant is that the long-range forecasts were maintaining the drought, with a high probability for below-normal rain. What ended up happening was well-above normal rainfall.
Many of us understand forecasts in general are probabilistic in nature. But in long-range forecasts, any time there is a 50% chance of one trend maintaining (below normal rainfall), and the opposite happens (above normal rainfall), it is safe to say that the exact opposite of the forecast happened. In other words... reality bucked the forecast probabilities. (I'd start busting out math with standard deviations and such... but I'm lazy)
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