Monday, October 13, 2014

AL08 Gonzalo

http://www.ssd.noaa.gov/PS/TROP/floaters/08L/imagery/avn-animated.gif
The most current satellite loop of Gonzalo (Updates Automatically)
10/16/2014 Update:
Hurricane Gonzalo peaked again this afternoon as a Category 4 storm with 145 mph winds and a central pressure of 940 millibars. This is the strongest hurricane in the Atlantic since Hurricane Ophelia in 2011. Bermuda is now in for a very close or direct hit from a major hurricane tomorrow. Fortunately, Gonzalo is undergoing another eyewall replacement cycle, which make result in some weakening. In addition, increasing shear and cooling sea surface temperatures should contribute to weakening.  This being said, microwave imagery and recon has indicated that the outer eyewall is closed, which means there is an eyewall ready to take the place of the collapsing inner one. The storm may not weaken very much tonight before impacting Bermuda, which is under a hurricane warning. The effects of Gonzalo on Bermuda are expected to be similar to Hurricane Fabian of 2003, one of the most destructive hurricanes to hit Bermuda. Gonzalo is forecast to have 130 mph winds at its closest approach while Fabian had 120 mph winds.
Microwave image of Gonzalo showing large and well organized outer eyewall depicted by a ring of red. The remnants of the collapsing inner eyewall is the yellow splotch inside the NE portion of the eye.

IR loop of Category 4 Hurricane Gonzalo during late morning.

10/15/2014 Update:
11:00 PM EDT
Gonzalo seems to have completed the EWRC and is beginning to pop out an eye again. The storm has weakened modestly to a 120 mph storm and can be expected to resume strengthening shortly.
Gonzalo popping out an eye

Microwave image showing the eye of Gonzalo in terms of  water clouds from convection.

8:00 PM EDT
Gonzalo strengthened to a category 4 hurricane with winds around 130 mph this morning. As reconnaissance aircraft was investigating the storm, they noted that the hurricane had concentric eyewalls on the plane's radar. By the time they left, the inner eyewall had contracted and the eye was just 5 miles in diameter. Soon after, the eye clouded over and  Gonzalo underwent an eyewall replacement cycle (EWRC), where the inner eyewall collapses and a new one typically takes its place. As a result the storm was downgraded to a category 3 hurricane with 125 mph winds. Over today, the eye has been largely clouded over and convection has been weaker than it had been previously, possibly due to dry air entrainment during the EWRC, which is often an issue. But recently, there has been a blowup of convection on the west side of the storm, indicating that a strengthening process may begin anew as large scale environment remains favorable.
The eye of Hurricane Gonzalo clouding over this morning as it begins undergoing an EWRC. At the time, Hurricane Gonzalo was a category 4 Hurricane with 130 mph winds.

IR loop showing the blowup of cold cloud tops (red and grayish silver)  associated with strong convection on the west side of Hurricane Gonzalo around 7:15 PM. At the time, Hurricane Gonzalo was a category 3 hurricane with 125 mph winds
The official forecast brings Gonzalo just to the west of Bermuda still as a major hurricane before sending it east of Newfoundland as a strong cat 1 hurricane transitioning to a extratropical storm. It is extremely unlikely that Gonzalo will directly affect the US mainland because a strong low pressure system (which brought us all the rain today) will push it out as it moves east.
An IR satellite image showing a well defined and strong low pressure system and cold associated cold front draped across the East Coast, which will move east, "hooking" Hurricane Gonzalo, causing it to recurve NNE past Bermuda and into the Northern Atlantic.

10/14/2014 Update:
BULLETIN
HURRICANE GONZALO ADVISORY NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082014
500 PM AST TUE OCT 14 2014

...GONZALO BECOMES A MAJOR HURRICANE OVER THE OPEN ATLANTIC...
...ADDITIONAL STRENGTHENING EXPECTED...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...21.2N 66.0W
ABOUT 330 MI...530 KM E OF GRAND TURK ISLAND
ABOUT 770 MI...1240 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.64 INCHES 

Hurricane Gonzalo strengthened to a major hurricane today while pulling away from Puerto Rico. It is expected to strengthen further to a category 4 hurricane. It likely will affect Bermuda as a weakening borderline major hurricane (winds of around 115 mph) and may later make landfall on Newfoundland with forecasted winds of 100 mph.

Satellite loops show that Gonzalo has developed a small eye and has very intense convection wrapping around eye, especially the eastern side. The eye has been steadily shrinking and Gonzalo may undergo a eyewall replacement cycle soon.

10/13/2014 Update:
For those of you who like color,a colorize infrared loop of Gonzalo. The redder the colder the cloud tops, which indicate strong convection.

Ir loop of Gonzalo, starting out as an area of disorganized thunderstorms well east of the Lesser Antilles before organizing and strengthening into a Tropical Storm.

Radar loop out of Martinique of Gonzalo organizing as it approaches and ultimately impacts the Leeward Islands. Note how a partial eyewall develops near the end of the loop. This as well as developing spiral (curved) bands of precipitation is a sign of strengthening.


ORIGINAL TEXT:
An area of low pressure originating from an African tropical wave that had been designated Tropical Storm Gonzalo a day ago has quickly strengthened. Winds around 75 mph were measured by reconnaissance aircraft in the storm. In addition, recon found a partial eyewall that is open to the south. Therefore, as of 4:00 PM EDT (5:00 AST), Gonzalo is officially the 7th named storm and the 6th hurricane of the season.

From the NHC:
BULLETIN
HURRICANE GONZALO ADVISORY NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082014
500 PM AST MON OCT 13 2014

...GONZALO BECOMES A HURRICANE WHILE MOVING THROUGH THE
NORTHERN LEEWARD ISLANDS...
...ADDITIONAL STRENGTHENING LIKELY...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...17.9N 62.9W
ABOUT 20 MI...30 KM SE OF ST. MARTIN
ABOUT 140 MI...230 KM ESE OF ST. THOMAS
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES
 
Gonzalo is currently battering the northern islands of the the Lesser Antilles in the Caribbean. Unverified reports of sustained winds of 76 mph and gusts up to 125 mph have been reported on the Island of Saint Barts island, which was struck by the western eyewall. Gonzalo is expected to begin to turn to the north, as a trough of low pressure over the US progresses east. While Gonzalo moves towards Bermuda, it is forecast to strengthen into a major hurricane with 115 mph winds before weakening as it approaches Bermuda.
Official NHC forecast graphic
Fortunately (or unfortunately for some) Gonzalo will not affect the US directly. You can thank the low pressure system that's producing tornadoes over the south for steering him out to sea. The same low pressure will also bring rain on Wednesday.