Invest 90L becomes Tropical Depression Seventeen in the eastern Atlantic
Posted by
Chris in Tampa on 9/24/2011, 5:02 am
5 Day NHC Track:
http://www.nhc.noaa.gov/refresh/graphics_at2+shtml/085617.shtml?5day?large#contents
TROPICAL DEPRESSION SEVENTEEN DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST SAT SEP 24 2011
THE SMALL AREA OF LOW PRESSURE SEVERAL HUNDRED MILES SOUTH OF THE
CAPE VERDE ISLANDS HAS DEVELOPED ENOUGH ORGANIZED CONVECTION TO BE
CONSIDERED A TROPICAL CYCLONE. MICROWAVE DATA FROM TRMM AND AMSR-E
OVER THE PAST FEW HOURS SHOWED DISTINCT CURVED BANDS...AND EARLY
MORNING VISIBLE IMAGES SUGGEST THAT THE CENTER IS WELL EMBEDDED
WITHIN THE CLOUD CANOPY. AN EARLIER ASCAT PASS INDICATED THAT THE
SYSTEM WAS CLOSED...AND HAD WINDS OF ABOUT 30 KT...SO THAT WILL BE
THE INITIAL INTENSITY. ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR STRENGTHENING FOR THE NEXT COUPLE OF DAYS WHILE THE
DEPRESSION IS OVER WARM WATERS WITH LIGHT SHEAR. AFTER THAT TIME...
THE CYCLONE COULD WEAKEN SOMEWHAT DUE TO INCREASING SOUTHWESTERLY
SHEAR FROM A LARGE UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC
OCEAN AND DECREASING SSTS. THE NHC INTENSITY FORECAST IS ON THE
CONSERVATIVE SIDE OF THE GUIDANCE ENVELOPE...BUT FOLLOWS THE TREND
OF THE LGEM MODEL.
BEST ESTIMATE OF THE INITIAL MOTION IS 280/12. A MID-LEVEL RIDGE TO
THE NORTH OF THE DEPRESSION IS FORECAST TO WEAKEN...WHICH SHOULD
CAUSE THE CYCLONE TO GRADUALLY TURN TOWARD THE WEST-NORTHWEST AND
NORTHWEST OVER THE NEXT FEW DAYS. SOME OF THE GUIDANCE TURNS THE
SYSTEM MORE TOWARD THE NORTH BY THE END OF THE FORECAST PERIOD DUE
TO A STRONG MID-LATITUDE TROUGH. FOR NOW...MOST OF THE RELIABLE
GLOBAL MODELS SHOW THE TROUGH STAYING FAR ENOUGH AWAY FROM THE
DEPRESSION TO AVOID RECURVATURE...AND THE NHC FORECAST IS ON THE
LEFT SIDE OF THE GUIDANCE ENVELOPE AND NOT TOO FAR FROM THE ECMWF
MODEL.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0900Z 10.7N 25.2W 30 KT 35 MPH
12H 24/1800Z 11.1N 27.2W 35 KT 40 MPH
24H 25/0600Z 11.8N 29.3W 40 KT 45 MPH
36H 25/1800Z 12.7N 31.4W 50 KT 60 MPH
48H 26/0600Z 13.7N 33.1W 60 KT 70 MPH
72H 27/0600Z 16.0N 35.5W 60 KT 70 MPH
96H 28/0600Z 18.0N 37.5W 55 KT 65 MPH
120H 29/0600Z 20.0N 39.5W 50 KT 60 MPH
$$
FORECASTER BLAKE
TROPICAL DEPRESSION SEVENTEEN ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST SAT SEP 24 2011
...ANOTHER DEPRESSION FORMS IN THE TROPICAL ATLANTIC OCEAN...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...10.7N 25.2W
ABOUT 290 MI...465 KM S OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 500 AM AST...0900 UTC...THE CENTER OF TROPICAL DEPRESSION
SEVENTEEN WAS LOCATED NEAR LATITUDE 10.7 NORTH...LONGITUDE 25.2
WEST. THE DEPRESSION IS MOVING TOWARD THE WEST NEAR 15 MPH...24
KM/H. A MOTION GENERALLY TOWARD THE WEST-NORTHWEST WITH A GRADUAL
DECREASE IN FORWARD SPEED IS FORECAST FOR THE NEXT COUPLE OF DAYS.
MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHER
GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND THE
DEPRESSION COULD BECOME A TROPICAL STORM LATER TODAY.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB...29.74 INCHES.
HAZARDS AFFECTING LAND
----------------------
NONE
NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 AM AST.
$$
FORECASTER BLAKE |
267
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Invest 90L becomes Tropical Depression Seventeen in the eastern Atlantic - Chris in Tampa, 9/24/2011, 5:02 am Post A Reply
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