Tropical Depression TWENTY-SEVEN forms E of Carribean... headed Gulfwards

Tropical Depression TWENTY-SEVEN

COMMENTARY FROM JEFF MASTERS
http://www.wunderground.com/blog/JeffMasters/show.html

The tropical disturbance that has festered over the waters between Panama and Nicaragua the past three days has dissipated, and tropical storm formation is no longer expected in this region.

A new area of disturbed weather has developed about 80 miles south of Barbados this morning. A low level circulation center is apparent near 12N 59W on both visible satellite imagery and an 8 am EDT QuikSCAT satellite pass. Deep convection associated with this 1007 mb low is mostly to its north, where the QuicSCAT satellite saw winds of up to 35 mph. Wind shear is quite high for tropical storm formation to occur, about 20 knots, but this shear is expected to decrease over the next few days. A tropical depression could form as early as Monday as the system crosses the Lesser Antilles islands into the eastern Caribbean. It is more likely, however, that development would occur Wednesday or later as the system moves into the central Caribbean.

The models are not gung-ho on this system, except for the Canadian model, which brings it quickly to hurricane strength just south of Hispanolia on Wednesday. The GFS model doesn't develop the system at all, and the other models forecast a weak tropical storm in the central Caribbean by Thursday.

OFFICIAL TRACK FORECAST:
http://www.nhc.noaa.gov/storm_graphics/AT27/refresh/AL2705W5_sm2+gif/025133W_sm.gif

INTENSITY FORECAST:
http://www.nhc.noaa.gov/storm_graphics/AT27/refresh/AL2705I_sm2+gif/025133P_sm.gif

OCEAN TEMPERATURES:


COMPUTER MODELS:

:rofl:

00
WTNT42 KNHC 140259
TCDAT2
TROPICAL DEPRESSION TWENTY-SEVEN DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
10 PM EST SUN NOV 13 2005

SATELLITE IMAGERY... SURFACE OBSERVATIONS... AND RADAR DATA FROM
MARTINIQUE INDICATE THUNDERSTORM ACTIVITY HAS CONTINUED TO INCREASE
AND BECOME MUCH BETTER ORGANIZED IN ASSOCIATION WITH THE LARGE LOW
PRESSURE SYSTEM LOCATED OVER THE SOUTHEASTERN CARIBBEAN SEA. AT
14/0000Z... ST. LUCIA REPORTED SUSTAINED SOUTHEAST WINDS OF 29 KT
...AND SHIP ZCBU6 LOCATED JUST OFF THE SOUTHWEST COAST OF REPORTED
SOUTHEAST WINDS OF 27 KT. SURFACE PRESSURE ANALYSES AT 00Z SUPPORT
A MINIMUM CENTRAL PRESSURE OF AT LEAST 1007 MB... CORRESPONDING TO
APPROXIMATELY 32 KT. RADAR DATA FROM MARTINIQUE SHOW CURVED
CONVECTIVE BANDING HAS DEVELOPED NEAR AND EAST OF THE LOW-LEVEL
CENTER... WHICH IS COINCIDENT WITH THE LARGE AREA OF -80C TO -82C
CONVECTIVE TOPS THAT HAVE BEEN NOTED IN INFRARED SATELLITE IMAGERY
SINCE 22Z. THEREFORE... THE LOW PRESSURE SYSTEM HAS BEEN UPGRADED
TO TROPICAL DEPRESSION TWENTY-SEVEN.

THE INITIAL MOTION ESTIMATE IS 300/09. THE DEPRESSION IS STILL IN
THE FORMATIVE STAGES... SO THERE MAY SOME ERRATIC MOTION FOR THE
NEXT 24 HOURS UNTIL THE CONVECTION BECOMES MORE CONSOLIDATED AROUND
THE CENTER. HOWEVER... THE GENERAL TREND BY THE VARIOUS GLOBAL
MODELS AND THE GFDL MODEL IS FOR THE CYCLONE TO PROPAGATE
WEST-NORTH OR NORTHWESTWARD FOR THE NEXT 24-36 HOURS TOWARD A
WEAKNESS IN THE SUBTROPICAL RIDGE LOCATED OVER THE NORTHEASTERN
CARIBBEAN SEA AND NORTHERN LESSER ANTILLES. AFTER THAT... THE
UPPER-LEVEL TROUGH THAT HAS CREATED THE WEAKNESS IS FORECAST TO
SLOWLY WEAKEN AND LIFT OUT TO THE NORTHEAST... ALLOWING THE RIDGE
TO BUILD EASTWARD TO THE NORTH AND NORTHEAST OF THE CYCLONE. THIS
SHOULD ACT TO THE DRIVE THE STORM WESTWARD ACROSS THE CENTRAL
CARIBBEAN SEA IN THE 48-120 HOUR FORECAST PERIODS. THE OFFICIAL
FORECAST TRACK IS CLOSE TO A BLEND OF THE NOGAPS... UKMET... AND
GFDL MODELS.

UPPER-LEVEL WESTERLY SHEAR OF 20-25 KT IS EXPECTED TO CONTINUE
ACROSS THE CYCLONE FOR THE NEXT 36-48 HOURS... WHICH SHOULD INHIBIT
ANY RAPID DEVELOPMENT DURING THAT TIME. AFTERWARDS... THE SHEAR IS
EXPECTED TO DECREASE TO LESS THAN 10 KT... AT WHICH TIME MORE
SIGNIFICANT DEVELOPMENT COULD OCCUR. THE SHIPS MODEL BRINGS THE
INTENSITY UP TO 66 KT IN 108 HOURS... WHEREAS THE GFDL MAKES THE
CYCLONE A 112-KT MAJOR HURRICANE AT THE SAME TIME. IT SHOULD BE
POINTED OUT THAT THE SHIPS INTENSITY MODEL FORECAST WAS BASED ON
THE MEDIUM BAM MODEL FORECAST TRACK... WHICH TAKES THE STORM
SOUTHWESTWARD ACROSS COLOMBIA WHERE UPPER-LEVEL WINDS ARE EXPECTED
TO BE MUCH STRONGER THAN THEY ARE OVER THE CENTRAL CARIBBEAN SEA.
IT IS QUITE POSSIBLE THAT THIS SYSTEM COULD END UP STRONGER THAN
INDICATED AFTER 72 HOURS... GIVEN THE MUCH LOWER VERTICAL WIND
SHEAR THAT THE GLOBAL MODELS ARE FORECASTING TO BE IN PLACE OVER
THE 96- AND 120-HOUR OFFICIAL FORECAST POSITIONS.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 14/0300Z 13.5N 62.7W 30 KT
12HR VT 14/1200Z 14.3N 64.1W 30 KT
24HR VT 15/0000Z 15.3N 65.7W 35 KT
36HR VT 15/1200Z 15.9N 67.2W 35 KT
48HR VT 16/0000Z 16.1N 68.8W 40 KT
72HR VT 17/0000Z 16.0N 72.2W 45 KT
96HR VT 18/0000Z 16.0N 75.5W 50 KT
120HR VT 19/0000Z 16.0N 79.0W 60 KT

$$

So far we have dodged Katrina and dealt with Wilma. I really don't even want to think about Gamma.

TS 27? Did they run out of the Greek alphabet, too?

If it develops enough for that, it will be Gamma.

is turning into Frat Row. :+

<>

... The Virgin Islands observe a Thanksgiving Day (October 25) to rejoice in the end of the hurricane season.

Think we should tell them and ruin their Thanksgiving.

After suffering through the made-for-TV movie "Category 7: End of the World" about meteorologically impossible storms that nearly destroy the world, I came back to the all-too-real world of the Hurricane Season of 2005, which I would have thought was a near impossibility had you told me before the season started what would transpire. Twenty-seven tropical cyclones? Unreal!

Tropical Depression 27 is very unimpressive tonight. Wind shear is still rather high right now, at 10 - 15 knots, and these hostile winds are keeping the area of deep convection around the storm small. The shear may even act to tear the storm apart Monday or Tuesday. TD 27 does have the potential to grow into a hurricane, and possibly a major hurricane, if it can survive the next two days and make it into the central Caribbean where the waters will be warmer and the wind shear lighter. I'll be back in the morning with a full analysis.

Jeff Masters

I knew I'd find you on the hurricane thread. :hi:

Check this out:

http://www.nhc.noaa.gov/storm_graphics/AT27/refresh/AL2705W5_sm2+gif/023909W_sm.gif

Look at that little crook to the north, toward the Yucatan.

Hi Maddy,

Should be lots of relief with this news...

:evilgrin:

Three more hurricane seasons under Buckaroo Bush's disaster relief bungling, and it won't just be the long-suffering American public who'll be able to say that Buckroo Bush rode America hard and put her away wet.

:mad:

http://www.wunderground.com/blog/JeffMasters/show.html

Wind shear from strong upper-level westerly winds has disrupted Tropical Depression 27 this afternoon. The depression was probably near tropical storm strength for a few hours late this morning, but since that time, the center of circulation has become more exposed, and the deep convection has retreated to the southeast side. The spiral band that had formed to the south is gone now. Wind shear is continuing to drop, and is now in the 15 - 20 knot range. This shear is still high enough that there remains a 10% the depression will dissipate within the next 48 hours. If the storm can survive until past then, the shear will decrease enough to allow TD 27 to strenghen into a tropical storm and remain in a threat to the Caribbean for the rest of the week.

The eventual intensity of TD 27 is highly uncertain, and will be highly dependent on the track of the storm. If TD 27 can position itself under an upper-level anticyclone that is expected to develop by Wednesday over the central Carribean, the storm has a chance to attain hurricane status. Ocean temperatures are 28-29C--plenty warm enough to allow a hurricane to form. The GFDL model still predicts TD 27 will intensify into a major Category 3 hurricane by the end of the week. However, the other major intensity model, the SHIPS model, forecasts a strong tropical storm by the end of the week. There is no way to tell now which model is more likely to be correct.

The computer models agree on the basic idea that TD 27 will track westward over the Caribbean for the next five days, under the steering of a strong ridge of high pressure. By the end of the week, the models begin to diverge.
The GFDL and NOGAPS depict a stronger system and show a threat to Jamaica, while the GFS and UKMET have a weaker system farther south that is more of a threat to Honduras and Nicaragua. None of the models show the storm moving far enough north to get caught in the westerly winds prevailing over Cuba and getting recurved out to sea. It appears that the ridge of high pressure steering TD 27 westwards will continue to hold in place for at least seven days, making Honduras the most at-risk area for a strike. Remember, a lot can change with forecasts for the large-scale weather patterns five to seven days from now, and the future track that far in advance will depend heaviy on how intense the storm becomes.

The Hurricane Hunters are scheduled to make their first flight into TD 27 Tuesday afternoon.

I'll be back with an update in the morning, unless TD 27 gets a name tonight. Incidently, TD 27 is only the 3rd tropical depression in history to form in November in the eastern Caribbean.

Jeff Masters