Hurricane Ernest To Hit Mexico Tonight

Ernesto underwent some intensification today, reaching hurricane strength as of the most recent advisory update from the National Hurricane Center.  Within the next 12 hours, Hurricane Ernesto will make initial landfall along the Mexican coast, north of Belize.  He is predicted to spend just under 24 hours moving over Mexico (weakening to a Tropical Storm) before re-emerging over the warm southern Gulf of Mexico waters.  Just over one day later, Ernesto will likely make second landfall along the Mexican coast (likely re-strengthening to a hurricane).

Hurricane Ernesto’s center is currently located near 18.8N 86.2W; has a central minimum pressure of 983mb; has maximum sustained winds of 80mph; and is moving WHW @ 15mph.  Hurricane Ernesto has a very good satellite appearance with concentric outflow and cold cloud-top temperatures:

Hurricane Ernest is predicted to continue moving generally westward, then curving slightly south of west over the next five days:

T.S. Ernesto Strengthening, Likely To Hit Belize; T.S. Flornece Dissipates

Tropical Storm Ernesto

Tropical Storm Ernesto raced across most of the Caribbean Sea over the weekend but is now slowing down.  Due to its speed and lack of development, T.S. Ernesto remained further south than some models had predicted.  Now that the storm has slowed down, it can strengthen over the warm western Caribbean waters.  He is likely to make landfall along the coast of Belize Wednesday morning.

T.S. Ernesto’s center is located near 15.8N 80.5W; has a central pressure of 994mb (and falling); has maximum sustained winds of 65mph; and is now moving WNW at only 9mph.

T.S. Ernesto is predicted to steadily strengthen over the next 48 hours and top out with 90mph sustained winds.  He should reach hurricane strength sometime in the next 24 hours.  While over Belize and southeastern Mexico, Ernesto will weaken.  There is a chance the storm will re-emerge over the southern Gulf of Mexico and regain some of its strength before making a second landfall over the eastern coast of Mexico near the southwestern Gulf of Mexico.  Thereafter, the storm will dissipate over the Mexican landmass.

Figure 1. NHC’s map of Ernesto’s current position and likely future track and intensity forecast as of 2P EDT on 20120806.  Circles with H’s indicate hurricane strength; with S’s indicate tropical storm strength; with D’s indicate tropical depression strength.

Unfortunately, there will not be any potential for short-term drought relief by Ernesto over the US.  Mexico will benefit from its likely prodigious rainfall, however.

Tropical Storm Florence

T.S. Florence has dissipated and is now a post-tropical cyclone.  Its center is located near 16.4N 40.2W; has maximum sustained winds of 35mph; is moving W at 15mph.

The storm complex that was Florence will gradually turn toward the northwest over the next five days, remaining well out to sea.  Recall that this was a Cape Verde storm and this track and behavior is common for these type of storms: they simply form too far east to have any impact on any Western Hemispheric landmasses.

Other Potential Storms

Another tropical wave has transited Africa, but this wave is much weaker than Ernesto or Florence was.  The next tropical wave is just west of central Africa and should enter the Atlantic Ocean in a few days’ time.  No other tropical development is likely in the next week.

T.S. Ernesto Moves Through Caribbean; T.S. Florence Forms In Eastern Atlantic

T.S. Ernesto

T.S. Ernesto continues to move in a generally westward direction this weekend.  The storm looks very impressive in satellite imagery, but has gone through cycles of strengthening and weakening due to dry air and moderate wind shear.

T.S. Ernesto’s position is  ~14.5N, 69.3W; minimum central pressure 1004mb; maximum sustained winds 50mph; moving W @ 18mph (rather quick for a tropical system).

The NHC is forecasting Ernesto to become a hurricane in the western Caribbean as the storm moves over water with higher heat content.  There is large uncertainty in this forecast because of the wide spread of model solutions of storm intensity.  The intensity the storm does possess will make a large contribution in the determination of its path.  If the storm stays weak, it should hit Belize or the Yucatan Peninsula early on Wednesday (the GFS, BAMM and UKMET models show this solution).  If the storm strengthens to a Category 1 or 2 hurricane, it should follow a weakness in the ridge guiding its movement due to a frontal system moving east across the US early in the week.  If this happens, the storm could take a path east of the Yucatan Peninsula and move in the Gulf of Mexico (as shown by the GFDL and HWRF models) where it would likely continue to intensify prior to a US landfall.  As of right now, the NHC’s official track forecast takes Ernesto over the Yucatan, north of Belize, then into the southwestern Gulf of Mexico on Thursday.

It is worth mentioning that the US is currently in the midst of the longest streak without a major hurricane making landfall on the continental US (2,476 consecutive days and counting).  The last storm to do so was Hurricane Wilma on December 4, 2005!

T.S. Florence

T.S. Florence strengthened from a very vigorous African tropical wave late yesterday.  She formed WSW of the Cape Verde islands and is moving generally westward across the Atlantic.

T.S. Florence’s center is currently at 14.8N 30.6W; her minimum central pressure is ~1002mb; maximum sustained winds are at 45mph; moving WNW @ 16mph.

Storms like Florence usually remain well out in the middle of the ocean and don’t impact landmasses such as the US or even the Caribbean.  Their exact paths are taken in response to the strength and position of the ridge of high pressure over the Atlantic as well as the transit of mid-latitude troughs north of the tropics that temporarily weaken that ridge.

T.S. Florence is officially projected to continue moving approximately WNW to NW over the next five days.  By Thursday, the storm could be well northeast of the Lesser Antilles.  The extended range GFS model keeps Florence out to sea with the storm turning to the north hundreds of miles east of the US coast.  Florence could experience some trouble strengthening due to the lower sea surface temperatures and lack of deep warm water from which to grow.

Note that yesterday was the 3rd earliest date on which the 6th storm of the Atlantic season formed.

2012 Atlantic Hurricane Season: T.D. 5 Forms In Mid-Atlantic

The vigorous African tropical wave in the middle of the Atlantic Ocean has organized itself enough to be classified as a Tropical Depression, marking the 5th to form in the 2012 Atlantic basin season.

The system is currently centered at 12.6N, 50.6W (still a long ways from the Lesser Antilles); has maximum sustained winds of 35mph; and is moving WNW at 18mph (a relatively fast speed for tropical systems).

Figure 1. IR image over the Central Atlantic.  Tropical Depression 5 can be identified by the mass of clouds just north of 10N, 50W.  The next African tropical wave can be seen east of 40W, between 5 and 10N.  The visual appearance of the depression will acquire a more typical cyclonic feature as it continues to organize and strengthen.

TD5 is expected to strengthen slowly over the course of the next week, attaining Tropical Storm strength by tomorrow morning and possibly Hurricane strength by Monday evening.  It is projected to pass over the central Lesser Antilles mid-day Friday and stay well south of Puerto Rico and Hispanola over the weekend before possibly passing just south of Jamaica Monday.  After that, the storm’s path is anyone’s guess.

Dry air to the storms north and somewhat higher wind shear should prevent the storm from quickly gaining strength during the next few days.  After that, intensification is anticipated to occur while the storm is over warm Caribbean waters.

1st African Tropical Wave of 2012 with a Chance of Development

The Atlantic basin has been relatively quiet so far this year.  While four tropical storms formed prior to July (the earliest on record), all of them were weak and short-lived since they formed on the western side of the basin.  This situation is largely due to higher wind shear than normal and a strong high pressure region, which pushes air toward the ground instead of lifting it.

The National Hurricane Center in Miami, FL has issued an outlook for an area of disturbed weather currently centered 1,150 miles southwest of the Cape Verde Islands.  The center is giving Invest 99L a 20% chance of tropical cyclone development within the next 48 hours – still pretty low, which means the system bears watching as it makes its way across the Atlantic over the next week.

The system is near 9°N 36°W.  9°N (click for a decent IR satellite image), which is relatively close to the Equator as far as tropical systems are concerned.  Disturbed weather at this latitude have a hard time acquiring the angular momentum necessary to grow into a cyclone.  If the system were to angle northwestward for a few days, it would stand a much better chance of development by the time it reached the Lesser Antilles.

Wind shear is minimal in the area (5-10knots).  Sea-surface temperatures have been warm enough for tropical cyclone development for months, so that’s not an issue with this system.

The GFS ensemble members project Invest 99L to move through the eastern Caribbean island chain sometime next week.  The specific timing for this will have to wait until we’re much closer in time.

Dr. Gray’s Team Trusts Medium-Term, Not Climate Models

Dr. William Gray is renowned for his work on Atlantic hurricanes.  He is also renowned for forcing his opinion related to climate change into discussions by climate scientists (this at the same time saying climate scientists have no business in tropical meteorology predictions…).  So it was with interest that I read a synopsis of his team’s latest seasonal forecast (the team is now headed by one of his former students, Dr. Klotzbach):

Expect one of the quietest Atlantic hurricane seasons since 1995 this year, say the hurricane forecasting team of Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU) in their latest seasonal forecast issued April 4.

The privately funded forecast contains interesting comments [emphasis mine]:

Everyone should realize that it is impossible to precisely predict this season’s hurricane activity in early April.

We issue these forecasts to satisfy the curiosity of the general public…

The reader will note that we are incorporating a dynamical SST forecast from the European Centre for Medium-Range Weather Forecasts (ECMWF). Hindcast data provided by Frederic Vitart indicates that the ECMWF model system 3 has significant forecast skill for SSTs across the various Nino regions for September from a 1 March forecast date. We utilize the ECMWF ensemble mean prediction for September Nino 3 SSTs. The ECMWF has recently upgraded to system 4. Hindcast data from this new model is not available yet, but it is assumed that the model has improved skill to system 3. Hindcast data from 1982-2010 show that the ECMWF forecast from system 3 from a 1 March issue date correlates with observed September Nino 3 SSTs at 0.63.

I have some comments about all of this, especially in light of the requirements Dr. Gray would apply to climate projections based on physics while his forecasts are based on statistical correlations derived by looking back in time.

It is impossible to predict precisely any variable into any type of distant future – months or years.  Yet Dr. Gray would have the public implicitly trust his forecasts, despite their limitations, and not climate predictions – which has something to do with the inaccuracy of climate projections.

They’re issuing forecasts to satisfy the public’s curiosity?  What if the public has a curiosity of the climate?  In Dr. Gray’s world, that doesn’t matter – simply because he says so.  The general public is currently being affected by climate change effects – quite a different scenario from hurricanes, which haven’t made landfall in the U.S. in years.  The future effects of climate change will grow in intensity and complexity – shouldn’t the public have access to climate projections so they can properly assess their risk and made decisions accordingly, much as coastal residents should do with potential hurricanes?

The last paragraph is laughable.  After years of telling people how much his technique benefited from observations (hence the statistical nature of his predictions), Dr. Gray’s team “trusts” the EMCWF – a numerical weather prediction model.  But at the same time, Dr. Gray has told the public (and testified to Congress) that models are inherently untrustworthy with respect to the climate.  Sea surface temperatures aren’t too complex to forecast in 6 months’ time, but the climate is more staggeringly uncomprehendable than any climate scientist will ever acknowledge, according to Dr. Gray.  From a scientists’ point of view, a correlation of 0.63, while positive, is far from inherently reliable.  If that’s the best performing variable, the team is relying more on belief than science.  And assuming that a newly upgraded model suite is as reliable as one you’ve performed hindcast verification on is a huge leap of faith.  I could write pages on the number of things that could and do go wrong when models are upgraded – the bugs are never worked out.

Dr. Gray’s hurricane forecasts should receive the same level and type of scrutiny that he demands of climate projections.  That he doesn’t speaks to how unbiased he really is.