Here we go again!

A SEVERE THUNDERSTORM WATCH is in effect for all of Central and Eastern New York until 9 tonight! The probabilities of damaging winds and hail are very high and it looks like everything is coming together in the atmosphere for a big severe weather outbreak. As of 2PM, there are only a couple of cells around. These cells will continue to form through the afternoon. They will then probably form into squall lines. Damaging winds are the largest threat, but hail and torrential rains are likely as well. There could also be a tornado or two around the region. More updates as things develop! Stay tuned!

Yet another Severe Thunderstorm Warning

We are currently under our THIRD severe thunderstorm warning of the day. A large cell has fired over Schuyler County and is moving towards the area. Hail and wind are threats with this storm, and it has taken trees down in Watkins Glen. However, I think the main threat may be flash flooding. The areas that were hardest hit earlier will once again get hit. As for a direct hit, it looks like West Groton stands a better chance than Groton, but, due to both Binghamton's and Buffalo's radars down right now, it is somewhat hard to tell. This storm will likely move into the Groton area between 10:30 and 11.

Flash Flooding, Severe thunderstorms: 5:15 Update

A very busy evening has unfolded. Tompkins County is currently under its second Severe Thunderstorm Warning. The first storm did some major damage in Freeville. PLEASE LET ME KNOW IF YOU HAVE DAMAGE!

Also, we have a FLASH FLOOD WARNING in effect until 9PM. This is because storm after storm keeps moving over the area. If you come across a flooded roadway, DO NOT DRIVE THROUGH IT. CALL 911 AND REPORT IT.

I will continue to update as needed.

Potentially Severe Cell: 4PM update

A thunderstorm with a hail potential is headed directly for Groton, probably striking within the next 30 minutes. Here is the latest radar:


The yellow square indicates a hail possibility. There could also be strong winds and torrential rain with this storm. Keep checking Grotonweather.com for any warnings that get issued, as well as for updates on additional storms throughout the evening and day tomorrow!

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Dean Explodes

HURRICANE DEAN HAS EXPLODED AND IS NOW A STRONG CATEGORY 4 STORM WITH WINDS OF 145 MPH. HERE IS AN EXCERPT FROM THE 11PM ADVISORY:

DATA FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT INDICATE THAT
MAXIMUM SUSTAINED WINDS ARE NEAR 145 MPH...230 KM/HR...WITH HIGHER
GUSTS.  DEAN IS A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE SCALE.  SOME ADDITIONAL STRENGTHENING IS FORECAST DURING
THE NEXT 24 HOURS.

Here is the latest radar from San Juan....it shows a very well defined eye, indicating a strong hurricane!

Major Hurricane Dean

Hurricane Dean became a Major Hurricane today (See post titled "TD-4 Forms, Saffir-Simpson Scale" 8/13) as it achieved category 3 status. It has winds of 125mph, which means its already half way to category 4 status. Dean is expected to continue to strengthen. Right now, Dean is in the eastern Caribbean Sea, south of Puerto Rico.

Here is the current radar out of San Juan, Puerto Rico, on which I pointed out the Eye of Dean, its movement, and Puerto Rico.


Dean is expected to head west before turning a bit more northwest. As you can see in the image below, this would take Dean over the Yucatan Peninsula, then towards Southern Texas.

This is a particularly bad situation for a number of reasons. First off, the Gulf of Mexico is a breeding grounds for hurricanes. With water temperatures often in the upper 80's, storms can rapidly intensify. Katrina is a perfect example. Katrina was a weak hurricane as it moved over Florida. Within 24-36 hours, it blew up into a category 5 storm. Interacting with the Yucatan Peninsula will probably weaken Dean some to counteract this, but Dean could still explode, especially if it misses the Yucatan.

Texas also just got hit with torrential rains from Erin and many places have had a record breaking summer for rain anyways. A powerful hurricane would only intensify these problems. Stay tuned for more as the days go on!

6:30PM Severe Storm

I was out storm chasing during the storm that just blasted Groton. In West Groton, I experienced quarter sized hail. Here are some quick pictures:


There is another storm to the northwest that looks like it will be following the same track as the last one. I will be out storm chasing again, so don't expect an update!

Where will Dean go?

Dean has become the first hurricane of the season. As of 7AM today, it has peak winds of 80mph and is expected to continue strengthening. In fact, according to the National Hurricane Center, by this time Sunday, Dean has a 40% of being a major hurricane, with winds any where over 111mph. So, where is this potential monster headed? And how will Puerto Rico, where a couple of Groton Residents will be this weekend, fare?

As you can see below, the projected track takes Dean through the Caribbean Sea and towards the Yucatan Peninsula of Mexico.



However, keep in mind that the projected path is of the center of the storm, where as the storm is much bigger. Taking a look at the chances for Tropical Storm and Hurricane force winds will give a better idea of who will be effected by this storm:



The hurricane force winds map isn't showing much since these maps were issued before Dean became a hurricane. In general, Puerto Rico is going to have a period of heavy rain and high winds. However, it shouldn't last too long, and it looks like it might come at night, so our fellow Grotonites shouldn't have their vacation ruined!

TD 4 Forms, Saffir-Simpson Scale

The system that was the subject of the last blog post has taken its first step to becoming a major player in the weather during the next 7-14 days. The system has become a tropical depression, the weakest classified tropical system. Winds are currently sustained at 35 mph. As you can see below, the system is still a very long ways from land. Based on historical data of storms that form in that area, the projected path looks fairly consistent. However, those projections can change in a hurry, so don't put too much stock in them until the system evolves more.


So of course, the next questions are: How strong will this become and where will it head? Neither of those questions can be answered for sure yet; its still a very young system, being upgraded just today. However, I do think there is a good bet it will become a hurricane, possibly a "major" one. Some of the "experts" from Accuweather.com have been saying Florida looks like a prime target. But in reality, its impossible to tell with any degree of certainty.

Wait a second...a "major" hurricane? What does that mean? Since hurricane season is heating up, its a good time to review the "Saffir-Simpson Scale," which is used to measure hurricanes based on wind speeds. There are 5 categories of hurricanes, 1 being the weakest, 5 the most powerful and rarest. Anything with a category 3 or higher is considered a "major" hurricane. Here is the complete scale, just focusing on categories and wind speeds:

• Category 1: Winds between 74-95 mph
• Category 2: Winds between 96-100 mph
• Category 3*: Winds between 111-130 mph
• Category 4*: Winds between 131-155
  
• Category 5*: Winds over 156 mph

*Denotes a major hurricane

Now, these winds are sustained winds. Sustained winds are a 1-minute average. Individual gusts within the hurricane can far exceed the sustained wind speeds.

Keep checking back for updates on TD-4, which will like be named either "Dean" or "Erin" depending on another area of disturbed weather in the Western Gulf of Mexico.

Vigorous Tropical Wave Needs Watching

For days now, models have been saying a tropical wave would develop into a hurricane and churn across the Atlantic. Friday, the system in question came off the coast of Africa as a vigorous tropical wave. This wave has stayed healthy in its first 36 hours over water and could become a tropical depression as soon as this afternoon or evening. Conditions look favorable and the models still agree that this should become a hurricane. The thing the models haven't been agreeing on is where this will go, ranging from Mexico to Maine. Most times with storms that form where this one is, it is somewhere between Florida and Virginia that gets hit. Of course, it is way way way too soon to tell where it will go. The storm is still 10-14 days away from the United States coast. I will be posting updates through the week, so stay tuned!