20 October 2014

Tropical disturbance brewing in the Gulf of Mexico

Just a day after Gonzalo transitioned to an extratropical cyclone south of Greenland, our attention shifts back to the tropics.  A very disorganized low pressure area is festering in the Bay of Campeche... my update on the system can be found on the Capital Weather Gang blog:

Tropical disturbance brewing in the Gulf of Mexico

18 October 2014

Gonzalo passes directly over Bermuda Friday night

The hit could not have been any more direct.  There was a moment when the large eye of the hurricane was centered so perfectly over the island that there were light northerly winds on the west side of the island and light southerly winds on the east side.  That was at 9pm local time, and the corresponding radar and satellite images are shown below:

(Bermuda Weather Service)
(Naval Research Laboratory Monterey)
The complete long-range and short-range radar loops from Bermuda (as well as earlier ones from Puerto Rico and Guadeloupe) can be found at http://andrew.rsmas.miami.edu/bmcnoldy/tropics/radar/

As you can tell from the lopsided satellite presentation, it was becoming sheared and beginning to show signs of an extratropical transition.  The radar and satellite images are from the same time (0100Z on the 18th).

During the day on Friday, I captured a series of webcam images from Bermuda's cruise ship terminal.  The three images span 4 hours, but do not include the worst of the storm (you couldn't see ANYTHING then)... the rapid deterioration of conditions is evident.

St. Davids experienced a wind gust close to 150mph, but for the most part, winds were characteristic of a Category 2 storm... still plenty strong to inflict severe damage.  It will take some time to sort out what all happened there, and as I write this, sunlight is just returning to the island.  There will likely be extensive damage to trees as well as piers/docks/marinas.  Reports indicate that about 85% of the island is without power.

Weather balloons are released twice a day at about 800 locations around the world every day to collect atmospheric data.  Bermuda is one of those sites, and at the regularly scheduled time, they were inside Gonzalo's large eye and released the radiosonde on time... what an incredible coincidence.  Here is that sounding for posterity:

The current satellite image and forecast track are shown here, and that track will take Gonzalo over very cold water beginning tonight, and it is expected to become an extratropical cyclone by Sunday afternoon as it zips off to the north central Atlantic hurricane graveyard.

This was a very bizarre week in an otherwise quiet season.  To have Tropical Storm (almost hurricane) Fay hit Bermuda last Sunday and then Hurricane Gonzalo hit on the following Friday night is the worst possible luck!  The debris from Fay was still not picked up completely when Gonzalo hit.

For now, the only area of possible interest in the coming days is in the Bay of Campeche, so I'll keep a close eye on it!

17 October 2014

Trouble in paradise: Hurricanes threaten Bermuda and Hawaii

Today's update covers Hurricane Gonzalo in the Atlantic, and Ana in the Central Pacific.  Gonzalo will impact Bermuda on Friday afternoon, and Ana will impact Hawaii on Friday night.  The update is available on the Capital Weather Gang blog... as always, thanks for reading and sharing!

Trouble in paradise: Hurricanes threaten Bermuda and Hawaii

16 October 2014

Hurricane Gonzalo one day away from Bermuda

As of 8am EDT today, Gonzalo is a Category 4 hurricane with 140mph sustained winds.  As I pointed out before, this is the strongest Atlantic hurricane in three years (it's tied with Ophelia 2011).  The last storm that was stronger (not tied) was Igor 2010.

Ominous satellite image of Hurricane Gonzalo as of 9:15am EDT.  Bermuda is marked in red in the upper right corner.
Gonzalo completed the eyewall replacement cycle that I described in yesterday's update, and as is typical, it weakened slightly during the structural reorganization, then once the transition was complete, it re-intensified.  Additionally, every time an ERC occurs, the wind field expands in size (meaning that stronger winds cover more area).

Tropical storm (yellow) and hurricane (red) force wind swaths for Gonzalo since it formed through Thursday morning.  Notice how the wind field expands with time.  (NOAA)
It has also stopped moving westward, meaning that the recurvature toward Bermuda has begun.  As of 9am EDT, it's about 500 miles south-southwest of Bermuda and moving toward it at 9mph... a faster motion will begin today.  Tropical storm force winds extend up to 150 miles from the center (Bermuda is just 350 miles from those winds).

Models remain in tight agreement on the track over the next four days... it will make it closest approach to Bermuda early Friday afternoon and then make its closest approach to Newfoundland late Saturday night.  Both encounters will be quite significant.

Forecast from NHC's 8am EDT intermediate advisory. (NOAA)
As far as intensity goes, Gonzalo is still expected to be a major hurricane when it passes by Bermuda, which would be just the 4th major hurricane on record to hit Bermuda during October. The last 5 major hurricanes (and their intensities at closest approach) to pass within 100 miles of Bermuda are:
     - Fabian 2003:    120mph
     - Edna 1953:       120mph
     - Unnamed 1948: 130mph
     - Unnamed 1947: 120mph
     - Unnamed 1939: 130mph
Gonzalo could be slightly weaker than Fabian when it reaches the island, but still a major hurricane.

You will be able to monitor the storm via radar and surface observations as it approaches.  There's also a pier station with 6-minute reporting and water levels.

Stay tuned for updates, and you can always find the latest forecast and advisories from the National Hurricane Center.

12 October 2014

Fay hits Bermuda, and Gonzalo in the making?

To catch up from Friday morning's post, STD 7 was upgraded Subtropical Storm Fay at the next advisory on Friday afternoon.  Then on Saturday morning, Fay officially transitioned from subtropical to tropical, and headed north toward Bermuda as expected.  It also strengthened to just below hurricane intensity (60kts) and passed directly over Bermuda on Sunday morning.

Early morning visible satellite image of Tropical Storm Fay (7am EDT).  Bermuda is the red speck just south of the circulation center.  Thin wispy outflow cirrus are evident on the side of the storm. (NASA)
Radar image of Fay shortly after "landfall". (Bermuda Weather Service)
In the coming days, Fay will weaken and become extratropical in the face of decreasing sea surface temperatures and increasing wind shear.

What's next?

The disturbance that I mentioned on Friday that was east of the Lesser Antilles has indeed gotten better organized.  It is now centered roughly 350 miles east of the Leeward Islands and moving west at 12mph.  It is nearing tropical depression status, and could be upgraded to TD8 today or tomorrow.  If and when it becomes a tropical storm, the name will be Gonzalo.

Visible satellite image of the disturbance east of the Leeward Islands.  (NOAA)
Models are still in excellent agreement on it developing, and on a northwestward track toward Puerto Rico.  Beyond that, it appears likely that a trough will steer it toward the north. 

Forecast tracks from the Oct12 06Z model suite.  There are 4 global models and 5 regional models shown here. (U. Albany)
With very low shear and very warm SSTs ahead of it, this could potentially develop quickly and be close to hurricane intensity by the time it passes east of Puerto Rico, so it's worth paying attention to!

10 October 2014

TD7/Fay could form today

[11am UPDATE: This was upgraded to Subtropical Depression 7]

Over the last several days, an upper-level low pressure system positioned north of the Leeward Islands has gradually been acquiring more and more tropical characteristics, including a surface circulation and thunderstorm activity wrapping more evenly around the center. Model guidance is in fairly good agreement on this feature developing into a subtropical or tropical storm, and the next name on the list is Fay.

The thermal and wind structure is on the border between subtropical and tropical, and a case could be made for either designation right now.  But since both subtropical storms and tropical storms get named, it would still become Fay (or a subtropical/tropical depression first).

In an average season (using 1981-2010), we would have 10 named storms and an ACE of 88.3 by this date... but this year we're at 5 named storms and the ACE is 35.8.  IF this gets named today, it will be the latest date for the 6th named storm since 1994 (Florence formed on November 2).

Global and regional models also agree on a future track: continue to drift slowly to the northwest, then begin turning to the northeast by Sunday.  It is not near land now, but could make a close approach to Bermuda on Sunday (that's the black speck near 32N 65W on the map below).

Elsewhere, there's a tropical wave centered near 15N 50W (about 730 miles east of the Lesser Antilles) today that is heavily favored by global models to develop into something significant in the coming days as it heads west-northwest.  If and when it shapes up a little more, I will give a full update on it.

Although the season has been quite inactive, it is important to note that October can still produce some very intense hurricanes.  It's not over 'til it's over, so stay tuned.

08 October 2014

Sea Level Rise in Miami and Miami Beach

Since many people who read my blog reside on or near the coast, I think this non-hurricane-related post would be of general interest.  Although the focus is on data and observations from Miami, the theme and lessons apply just about everywhere.

Water, Water, Everywhere: Sea Level Rise in Miami

02 October 2014

Will quietest hurricane season in two decades continue in October?

Today's update on the status of the hurricane season so far and a look ahead can be found on the Capital Weather Gang blog:

Will quietest hurricane season in two decades continue in October?

As always, thanks for reading and sharing!