Sunday, August 23, 2015

Danny and a Danny Wanna-be

Hurricane Hunters were out early this Sunday morning to check out Danny in the Atlantic waters east of the Leeward Islands. They found it is very small, moving west at around 15 mph, and still holding its own at Tropical Storm strength of around 50 mph.

Most of the rain shown here in golds, oranges, and reds, are only present on the east and northern side of the system. 

It is still being impacted by strong upper level winds (wind shear), and will be its nemesis in the short term.

This is not a healthy storm. Those 50 mph winds stretch out from the center around 60 miles.

What should the islands expect?:
WIND:  Tropical-storm-force winds are expected within portions of the warning area by late tonight.

RAINFALL: Danny is expected to produce 2 to 4 inches of rain over the Leeward Islands through Monday.

Which Islands are under advisories?:
A tropical storm watch has been issued for Puerto Rico, Vieques,
Culebra, and the U.S. Virgin Islands.

The government of France has discontinued the Tropical Storm Watch
for Guadeloupe, St. Barthelemy, and St. Martin.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla

A Tropical Storm Watch is in effect for...
* Saba and St. Eustatius
* St. Maarten
* Puerto Rico
* Vieques
* Culebra
* U.S. Virgin Islands

A Tropical Storm Warning means that tropical storm conditions are expected, in this case within the next 24 hours.
What next?:
Both the GFS and ECMWF global models
continue to depict the system weakening and opening up into a wave within 48
hours.  
Given these signs, the official forecast shows
weakening as in the previous advisories.  However, because of the
uncertainties in tropical cyclone intensity prediction, it is
prudent to issue a tropical storm watch for Puerto Rico and the
U.S. Virgin Islands at this time.

Danny continues westward to west-
northwestward over the next few days as Danny moves on the southern side of a low- to mid-level ridge.
The track model guidance has shifted a little south on this cycle,
and so has the official forecast.  This is close to the latest
dynamical model consensus.  If Danny weakens faster than expected,
it could move even farther south of this track.

The system could bring much-needed rainfall to Puerto Rico over the
next few days.

The NHC track forecast now has Danny coming to an end over Hispaniola by Wednesday. 


Danny may have a wanna be twin. There is another system right behind it trying to organize.
NHC says:
Disorganized showers and thunderstorms are associated with a low pressure area located about 500 
miles west of the Cape Verde Islands. Environmental conditions are expected to be conducive for
development, and a tropical depression is likely to form by mid-week while the wave moves quickly westward at around 20 mph. 

By late this week, atmospheric conditions could become less favorable for tropical cyclone formation
  • Formation chance through 5 days...high...70 percent
  • Formation chance through 48 hours...medium...50 percent
This is what the local NWS office is saying regarding both Danny and the system right behind it:

DANNY CONTINUES TO WEAKEN AND DISSIPATION IS FORECAST BY NHC, BUT
WE OF COURSE CONTINUE TO MONITOR THIS...AS WELL AS ANOTHER AREA
OF INTEREST BEHIND DANNY OVER THE TROPICAL ATLANTIC. THE LATEST
GFS AND ECMWF ARE BULLISH IN DEVELOPING THIS AND KEEP IT JUST EAST
OF THE BAHAMAS AS THE AMPLIFYING TROUGH DEFLECTS IT. EVEN
SO...IT`S A LONG WAYS OUT AND THINGS CAN CHANGE, SO WE WILL
MONITOR THIS ONE AS WELL IN THE DAYS AHEAD. THE NEXT NAME IS
ERIKA






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