Archive for the ‘November Tropical Activity’ Category

HAITI IS NOT LIKELY TO ESCAPE TOMAS

Two independent left clicks will enlarge to the fullest.

Though Tomas has weakened to a tropical depression, indications are that intensification to at least a category 1 hurricane will occur in the predicted journey northward.  But, even as a lesser storm (tropical depression or tropical storm) the system can cause severe problems with fatalities.  Just last month 23 people died in Haiti from the results of regular seasonal rainfall events, according to Dr. Jeff Masters’ blog this morning!  The pitiful deforestation of that country allows for rapidly flooding streams and mass wasting events (e.g. mud slides) which can be deadly.

Certain deadly diseases can be spread by contaminated water which is a likely outcome of the flooding that Tomas will trigger.  Cholera is probably the greatest current concern.

I am alarmed by the projected probability path of the storm (see this morning’s cone of uncertainty above) because, if it turns out this way, Haiti will be under the influence of the right hand leading quadrant of Tomas.  That quadrant is typically the one possessing the strongest winds, most prominent storm surges, and greatest probability for imbedded mesoscale tornadic systems.

Of course, Haiti is not the only place that should be concerned.  For example, the Dominican Republic, Jamaica, and the Bahamas need to be “ready.”

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Tomas May Invade Haiti as a Hurricane

Plot Courtesy of Jonathan Vigh - Colorado State University

Even when you left click twice to get full enlargement, most of the individual model forecast plots are hard to read individually because of the “cluster” of agreement in anticipated general trend.  The only glaring exception you see is the CLP-5 which should be no surprise to those who study these spaghetti charts.  CLP-5 is the “CLImatology-PERsistance model 5-day” of the National Hurricane Center and is sometimes referred to as the CLIPER model for obvious reasons.  It tends to project the path of tropical systems as though they were going to conform to their “past track.”  So, more often than not, when there are changes in the steering influences the storms actually stray significantly from the persistence route.  Most other models account for anticipated steering changes.  This does not mean that the CLP-5 is of no value.  To the contrary, it is very useful tool particularly in accessing forecast accuracy of other models.

It appears that Tomas could become a serious problem for Haiti.  The country is over 98% deforested and that opens up a whole can of worms with regard to flooding, mud slides, and soil erosion.  Some small fraction of the deforestation has been due to natural causes (e.g. Hurricane Hazel in 1954) but the vast majority has been due to the impact of humans and their practices upon the environment, the poor management of same, and the general human and political condition. It is my sincere hope that the storm weakens significantly but the National Hurricane Center currently has the “weighted mean” plot (within the cone of uncertainty) taking it through Haiti as a hurricane.

I copied this 2002 image below using my free Google Earth download.  With yellow it shows a small part of the border between Haiti and the Dominican Republic at the Artibonite river.  The greater amount of deforestation on the side of Haiti (west or left side of the river) is clearly evident.  The eye altitude is 26,293 feet; a horizontal scale appears on the lower left.

Image Courtesy of Google Earth

My dear, long-time friend, Chuck Knighton, and his wife, Helen, are residents of northern Barbados and as of yet I have heard no news.  I do know that they have frequent power interruptions with ordinary thunderstorm weather – so communication could be down for quite a while.

Update on that 1:40 pm EDT 11-1-2010 – An e-mail from Chuck’s mother:

“Hi Toney,
Thanks so much for calling about the situation in Barbados! I have just recently spoken with Chuck’s sister in law who lives in the south of Barbados. She reports that they are all OK and the property sustained fallen trees and lots of rain! They do have household water, AND electricity (praise be!) and no one sustained injuries. Great news! They do not have phone service as yet, and I was really glad to have touched bases with someone!
Thanks again!!”

Ida – Some Model Plots released tonight – 11-9-09

Here are some model forecasts for Ida (release time 10 PM EST.  Left click the image to enlarge.

Ida11-9-09-WU2

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IDA – FORECAST PLOT RELEASED 11-9-09 NOON CST

Ida’s most recent forecast plot as presented by WeatherUnderground.com.


Ida11-9-09-11-9-09 12nCSTLeft click the image to enlarge.

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Ida Is Weakening As Predicted – 11-9-09

The visible satellite image below is from 10:15 AM Eastern Time.  Wind shear has increased over Ida and it has moved off the warm Loop Current.  Dry air has been drawn in and has significantly disrupted the storms symmetry.  Water temperatures under her are barely enough to support a hurricane.  My source expects 50 to 60 mph winds when she makes landfall.  My advice is to consult the Weather Channel on television and/or your favorite on-line sources.

Currently, 19 ft. waves are being formed by the storm’s winds.  After watching a satellite loop showing the storms movement, I placed a blue dot as my approximation of the center.

Ida11-9-09-1015aEST

Some of the information on this site is published close to “real-time”  particularly as it applies to tropical weather.  But it is important to remember that the only “official” source of information is the National Hurricane Center. Decisions concerning life or death, property, and such should not be made based solely on the information found on this site or any other sites that are recommended here. unless they are official. Listen to your local authorities when conditions are life-threatening or there is possible loss of property.


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IDA FORECAST – 11-8-09

Some of the information on this site is published close to “real-time”  particularly as it applies to tropical weather.  But it is important to remember that the only “official” source of information is the National Hurricane Center. Decisions concerning life or death, property, and such should not be made based solely on the information found on this site or any other sites that are recommended here. unless they are official. Listen to your local authorities when conditions are life-threatening or there is possible loss of property.


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THE ENTIRE FIRST PARAGRAPH THAT FOLLOWS  IS A DIRECT QUOTE FROM DR. JEFF MASTERS (PICTURED BELOW) THAT WAS CUT AND PASTED FROM HIS WEATHER UNDERGROUND SITE; DR. MASTERS IS MY MOST RELIABLE AND DEPENDABLE SOURCE WHEN IT COMES TO TROPICAL WEATHER; HE IS A DEDICATED ‘WINNER:”  ONE REASON WHY I DEPEND SO HEAVILY UPON HIS WORK IS THAT HE IS NOT OPERATING UNDER THE CONSTRAINTS OF NATIONAL WEATHER SERVICE FORECASTER BUT HE BENEFITS FROM THEIR INTERPRETATIONS AS WELL AS FROM OTHER NATIONAL WEATHER SERVICE RESOURCES.  HE IS DEDICATED, “UP FRONT,” AND RESPONSIBLE.

bio_jeffm
Dr. Jeff Masters

The forecast for Ida


Posted: 10:21 AM EST on November 08, 2009


“The high wind shear of 20 – 25 knots currently affecting Ida is forecast to persist at that level until Monday night. Some slow intensification is still possible while Ida remains over the exceptionally warm water of the Loop Current in the Gulf of Mexico, through tonight (Figure 2). Late tonight, Ida will be crossing over waters of 26°C, which is barely enough to support a hurricane. With shear still expected to be at 20 -25 knots, I expect weakening to begin early Monday morning and accelerate on Monday afternoon. At that time, Ida will encounter 40 knots of wind shear associated with a cold front over the Gulf of Mexico, and begin transitioning to an extratropical storm. Exactly how strong Ida will be when it reaches the coast early Tuesday morning–and indeed if Ida even does reach the coast–is a forecast with high uncertainty. The computer models have a tough time forecasting the evolution of a tropical cyclone into an extratropical cyclone, and the models are all over the place on what will happen. Most of the models foresee a landfall near 1 am EST Tuesday between Mississippi and Pensacola, Florida, then a path northeastward over the Southeast U.S. However, Ida could come to halt before reaching the coast and turn west towards Tampa (the UKMET model’s forecast), or turn south back over the Gulf of Mexico (the NOGAPS model’s forecast). In any case, storm surge and heavy rain appear to be the main hazards from Ida. The GFDL model (Figure 3) is forecasting rain amounts of 4 – 8 inches for a large swath of the Gulf Coast, and there is a risk of tornadoes if the warm air from the core of Ida pushes ashore.”  END QUOTE

From my point of view, (this is Cloudman23 writing) everyone on the Gulf Coast  from Mississippi to Key West should have a “heads up” mindset while Ida is out there.  As Dr. Masters said, the computer models have a difficult time when the tropical to extratropical metamorphoses takes place.  Furthermore, the chance of tornadoes (mentioned by Dr. Masters) in association with warm, moist air from Ida and its inherent instability in such situations, this storm should not be taken lightly.

11-8-09 Ida 3pEST

Ida’s Current Model Forecasts – 11-7-09

The total amount of thermal energy at the surface in the Western Caribbean is high and wind shear aloft is relative low so it is anticipated that Ida will intensify before striking the Yucatan Peninsula.  The Yucatan does not have the type of topography that we associate with significant weakening of a storm due to friction.  But, read what Dr. Jeff Masters says this morning about the fate of Ida after she enters the Gulf of Mexico:

“Once Ida crosses into the Gulf of Mexico on Sunday night, the storm will encounter much cooler SSTs and a strong trough of low pressure that will dump cold air into the storm and bring 40 knots of wind shear. This will cause Ida to lose its tropical characteristics and become a powerful extratropical storm with 45 – 55 mph winds. It is highly unlikely that Ida will hit the U.S. as a tropical storm, but it could still bring tropical storm-force winds of 45 mph to the coast next week as an extratropical storm.”

As for me, I have been favoring the Geophysical Fluid Dynamics Laboratory Model (GFDL) for the path that Ida will take; currently,  if I had to depend upon only one of the many models, that would be the one – in most instances anyway.  I have no real science to back that up – only my perception based upon experience.  Call it a “gut level” good feeling about the model’s past performance if you will.  Therefore I expect Ida to eventually curve rightward as the GFDL shows in the plot below.  By the time it does I expect it will have lost its tropical characteristics though the winds will still be strong.  In other words, it will become extratropical.  TO GET INSTRUCTIONS ON OBTAINING THE GFDL ANIMATION CLICK ON THE FOLLOWING LINK: https://cloudman23.wordpress.com/2008/08/30/gfdl-model-a-great-source-for-an-animation/https://cloudman23.wordpress.com/2008/08/30/gfdl-model-a-great-source-for-an-animation/

The prefix, extra, means “outside of” or “beyond.”  Extratropical cyclones are sometimes called cold core lows whereas tropical cyclones are warm core lows.  When a tropical cyclone draws in cold air (as usually happens when a front interferes with the storm) it becomes extratropical.  The majority of the world’s extratropical cyclones develop in the middle latitudes (30 degrees to 60 degrees latitude) and for that reason are often referred to as middle latitude cyclones.

Graphic courtesy of Jonathan Vigh of the Department of Atmospheric Science at Colorado State University

11-7-09Ida

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Gulf Coast Residents – Ida Is Worth Watching

Ida developed quickly – in fact at a record pace (see Jeff Master’s Weather Blog at http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1372).

Though relatively high wind shear could prevent Ida from becoming a significant threat to the U.S. mainland it is a storm that is worth watching, partly because warm Gulf waters could nurture it.

Here is a recent forecast plot from the National Hurricane Center (left click to enlarge image):

11-5-09 ida

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