06 July 2017

Tropical Depression Four forms far from land

The disturbance I wrote about yesterday was upgraded to Tropical Depression Four early Thursday morning.  It is located about halfway between the Lesser Antilles and the African coast in the deep tropics.

Enhanced satellite image of the deep tropical Atlantic.  Orange and red hues indicate dry dusty air, while blue and green hues indicate more moist air. (EUMETSAT)

Zoom-in view of TD4.  The fine whispy cirrus clouds radiating out from the center is a clue that upper-level winds are not very strong.
Although the vertical wind shear has relaxed for now, it is becoming surrounded by dry mid-level air which squelches thunderstorm activity, so it is not expected to develop too much more.  Some models indicate it could attain tropical storm status, but the National Hurricane Center keeps it as a Depression through the next three days before dissipating.

Again, if it gets named it would be Don, and would be about seven weeks ahead of the average date of fourth named storm formation.

21 June 2017

Tropical Storm Cindy to make landfall on Louisiana tonight

Since yesterday's update, Tropical Storm Bret dissipated off the coast of central Venezuela, but the system in the Gulf of Mexico was upgraded to Tropical Storm Cindy.  They were both named storms for a 6-hour period, which was the first such pre-July occurrence since 1968.  Cindy, the third named storm of the season, is about 8 weeks ahead of pace for an average season.

Although Cindy became organized and strong enough to earn a name, the big picture has not changed at all.  The structure is not very tropical-looking in appearance, with thunderstorm activity far-removed from the center, and an exposed mostly-dry low-level circulation center. Mild storm surge (1-4 feet) is occurring along the northern Gulf coast, and flooding from heavy rain is the biggest hazard as expected.

As of the Wednesday morning advisory, the center was located about 200 miles southeast of Galveston, and maximum winds are around 60 mph.  However, tropical storm force winds already extend over into coastal Mississippi.

Cindy is bringing tropical storm force winds, storm surge, tornadoes, and of course, LOTS of rain. Already, some impressive rainfall totals have been observed, as you can see in the map below:

I have a very long (and still updating) radar loop of the region available here.

Cindy will make landfall near the TX/LA border late tonight, though the impacts have been and will continue to be felt far east of the center.  After that, land and increasing wind shear will bring this storm to an end, but its remnants will dump rain from TX/LA/MS/AL up through TN and KY over the next couple of days.

There is nothing else in the foreseeable future, but the next name on deck is Don.

20 June 2017

Serious flood risk for northern Gulf Coast from potential tropical storm

Updates on the two storm systems of interest, one in the central Gulf of Mexico (pre-Cindy?) and one in the eastern Caribbean Bret), are available on the Capital Weather Gang blog:

Serious flood risk for northern Gulf Coast from potential tropical storm

16 June 2017

Outlook generally unchanged since Thursday's update

This will be very brief, since there isn't much to add other than to say that the forecast appears to still be on track.  The odds remain good that a tropical cyclone will develop near the Yucatan Peninsula in the next few days then drift toward the northwest or north through the Gulf of Mexico early next week.

This has been a slow-moving, slowly-evolving system, and that's not about to change.  If it congeals into something more centralized and organized, a tropical depression could form.  Once in the gulf, environmental conditions should be favorable for further development, and a tropical storm is certainly not out of the question.  If it reaches that intensity, it would be named Bret.

Regardless of the exact track, at this point, coastal impacts appear to be timed around Tuesday, though that is a rough guess for something that hasn't formed yet.

And the easterly wave I very briefly mentioned in yesterday's update remains a feature of interest.  Models tend to develop it for the next 4-5 days, then once it enters the eastern Caribbean, it encounters strong shear and loses its identity.  In the meantime, it could be something to watch in the Windward Islands in the Tuesday-ish timeframe.  It's currently centered about 1800 miles east of *French Guiana* (way south).

01 June 2017

Hurricane season kicks off today, and odds are it will be busier than normal

This season begins my 22nd year writing and sending out updates on tropical cyclone activity across the Atlantic basin.  I am also honored to be back for the 6th year as the tropical weather expert for the Washington Post's Capital Weather Gang.
The 2016 season was the most active since 2010.  What will this year have in store?  My introduction to the 2017 hurricane season can be found at:

Hurricane season kicks off today, and odds are it will be busier than normal

20 April 2017

Tropical Storm Arlene forms in far northern Atlantic

The low pressure system I mentioned in Wednesday morning's post was upgraded to Subtropical Depression One shortly later, then earlier today, it acquired enough characteristics of a tropical cyclone that it transitioned to Tropical Depression One. Now, as of Thursday afternoon, it has been upgraded again Tropical Storm Arlene... the first named storm of the 2017 season.  Maximum wind speeds are estimated to be 45mph, and the central pressure has fallen to 993mb.

However, this was a rather generous upgrade, given that the cyclone is nearly indiscernible from the neighboring monstrous extratropical low and attendant frontal boundary.  It will be completely erased very shortly. In the satellite image below, Arlene's center is marked with a yellow 'x', and its swirl is tiny compared to the cloud field in which it's embedded.

Just to reiterate the climatology of the first named storm, this is exactly two months before the average date of first storm formation (June 20). It is also the 6th pre-season named storm to form in the past 6 years. This is also the 7th use of the name Arlene, and it won't be the last (it will not be retired after this season)!

The next names on this year's list are Bret and Cindy, though there's no new activity in the foreseeable future.

19 April 2017

The first named storm of the hurricane season could form soon

Time to dust off the tropical cyclone blog... the Atlantic is slowly waking up.  I have a brief update on a weak storm in the central Atlantic available on the Washington Post's Capital Weather Gang blog:

The first named storm of the hurricane season could form soon

UPDATE, WEDNESDAY 11AM: The low pressure system of interest has been upgraded to Subtropical Depression One (still not named).