TROPICAL STORM PHILIPPE ADVISORY NUMBER 25
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST FRI SEP 30 2011
...PHILIPPE CONTINUES NORTHWESTWARD WITH NO CHANGE IN STRENGTH...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...21.9N 44.9W
ABOUT 1150 MI...1850 KM ENE OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 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 STORM PHILIPPE WAS
LOCATED NEAR LATITUDE 21.9 NORTH...LONGITUDE 44.9 WEST. PHILIPPE IS
MOVING TOWARD THE NORTHWEST NEAR 13 MPH...20 KM/H...AND THIS MOTION
IS FORECAST TO CONTINUE FOR MOST OF TODAY. A TURN TOWARD THE
WEST-NORTHWEST WITH SOME DECREASE IN FORWARD SPEED IS EXPECTED LATE
TODAY OR SATURDAY.
MAXIMUM SUSTAINED WINDS REMAIN NEAR 45 MPH...75 KM/H...WITH HIGHER
GUSTS. SOME STRENGTHENING IS POSSIBLE TODAY...BUT WEAKENING IS
LIKELY TO BEGIN LATE SATURDAY OR SUNDAY.
TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 85 MILES...140 KM
FROM THE CENTER.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB...29.65 INCHES.
HAZARDS AFFECTING LAND
----------------------
NONE
NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 AM AST.
$$
FORECASTER KIMBERLAIN
TROPICAL STORM PHILIPPE DISCUSSION NUMBER 25...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST FRI SEP 30 2011
CORRECTED INITIAL MOTION
THE RECENT EVOLUTION OF PHILIPPE IS A BIT OF A MYSTERY. A COUPLE OF
RECENT MICROWAVE OVERPASSES INDICATE THAT PHILIPPE HAS A WELL-
DEFINED EYE FEATURE IN THE LOW LEVELS...SUGGESTING THAT THERE HAS
BEEN A NET INCREASE IN THE STRUCTURAL ORGANIZATION OF THE CYCLONE
DURING THE LAST 24 HOURS. HOWEVER...GEOSTATIONARY SATELLITE IMAGES
INDICATE THAT THE CONVECTIVE PATTERN OF THE STORM IS SOMEWHAT
CHAOTIC...WITH THE MAIN CLUSTER OF DEEP CONVECTION WELL TO THE
NORTHEAST OF THE CENTER UNTIL RECENTLY. GIVEN THAT THERE HAS BEEN
NO APPRECIABLE CHANGE IN THE OVERALL ORGANIZATION SINCE THE LAST
ADVISORY...THE INITIAL WIND SPEED ESTIMATE IS HELD AT 40 KT.
ALTHOUGH THERE HAS BEEN A RELATIVE RELAXATION OF THE SHEAR DURING
THE LAST 12-24 HOURS...PHILIPPE HAS NOT STRENGTHENED YET. HOWEVER...
THE BETTER ORGANIZED LOW-LEVEL STRUCTURE OF THE STORM WOULD SEEM TO
BE CONDUCIVE FOR SOME INCREASE IN STRENGTH WHILE THE SHEAR REMAINS
LOW. WITHIN 24-36 HOURS...WEAKENING SEEMS LIKELY AS PHILIPPE SHOULD
ENTER A REGION DOMINATED BY THE VERY STRONG UPPER-LEVEL
NORTHWESTERLY WINDS ASSOCIATED WITH THE OUTFLOW OF OPHELIA.
ASSUMING THAT PHILIPPE CAN WITHSTAND WIND SHEAR OF THAT
MAGNITUDE...THERE COULD BE AN OPPORTUNITY FOR SOME INTENSIFICATION
TOWARD THE END OF THE FORECAST PERIOD. THE NEW NHC INTENSITY
FORECAST IS UNCHANGED FROM THE PREVIOUS ONE IN THE SHORT TERM BUT A
BIT LOWER AFTER 36 HOURS...JUST BELOW THE STATISTICAL-DYNAMICAL
GUIDANCE.
PHILIPPE APPEARS TO BE MOVING NORTHWESTWARD OR 315 DEGREES AT 11
KT...BUT THE LACK OF CONFIDENCE IN EARLIER CENTER FIXES MAKES THIS
ESTIMATE SOMEWHAT UNCERTAIN. GLOBAL MODELS SHOW PHILIPPE BEING
STEERED WEST-NORTHWESTWARD TO NORTHWESTWARD DURING THE NEXT DAY OR
SO ON THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL HIGH OVER THE
EASTERN TROPICAL ATLANTIC. AFTER THAT...AN AMPLIFYING MID- TO
UPPER-LEVEL TROUGH OVER THE EASTERN UNITED STATES SHOULD CAUSE
HEIGHTS TO RISE OVER THE CENTRAL ATLANTIC WHICH...IN TURN...SHOULD
RESULT IN PHILIPPE'S TURNING WESTWARD. THE NEW NHC TRACK IS
BASICALLY AN UPDATE OF THE PREVIOUS FORECAST AND CONTINUES TO
FAVOR THE ECMWF SOLUTION ON THE SOUTHERN SIDE OF THE GUIDANCE
ENVELOPE WHICH HAS A WEAKER VERSION OF PHILIPPE. THE OFFICIAL
FORECAST IS WELL TO THE LEFT OF MULTI-MODEL CONSENSUS AT LATER
TIMES SINCE MOST OF THE MODELS ASSUME A STRONGER CYCLONE.
FORECAST POSITIONS AND MAX WINDS
INIT 30/0900Z 21.9N 44.9W 40 KT 45 MPH
12H 30/1800Z 22.9N 46.2W 45 KT 50 MPH
24H 01/0600Z 23.9N 47.9W 45 KT 50 MPH
36H 01/1800Z 24.5N 49.8W 40 KT 45 MPH
48H 02/0600Z 24.9N 51.6W 35 KT 40 MPH
72H 03/0600Z 25.1N 55.4W 30 KT 35 MPH
96H 04/0600Z 25.0N 58.8W 30 KT 35 MPH
120H 05/0600Z 24.5N 62.0W 35 KT 40 MPH
$$
FORECASTER KIMBERLAIN
Bookmarks