Caribbean-On-Line's Caribbean Hurricane Blog



TROPICAL STORM HANNA DISCUSSION NUMBER 34

Published on September 5, 2008 5:57 AM | Comments

The good news on Hanna from our perspective is that it is finally clear of the Caribbean islands, the Turks & Caicos, and nearly clear of the Bahamas. That is our focus here since we are a Caribbean travel website. Unfortunately, the east coast of the US now has to deal with this storm - the good news for them is that it seems that it will not regain hurricane strength. I can imagine property damage, but hopefully there won't be any loss of life in the US like there was in Haiti with all this time to prepare.

TROPICAL STORM HANNA DISCUSSION NUMBER 34 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008 500 AM EDT FRI SEP 05 2008

A RECONNAISSANCE AIRCRAFT CURRENTLY SAMPLING HANNA RECENTLY FOUND PEAK FLIGHT-LEVEL WINDS OF 73 KT. THIS WOULD NORMALLY CORRESPOND TO SURFACE WINDS OF ABOUT 60 KT USING THE STANDARD REDUCTION. HOWEVER...THE WINDS WERE FOUND IN AN AREA ABSENT OF DEEP CONVECTION AND THE SFMR INSTRUMENT ONLY SHOWED ABOUT 51 KT IN THE SAME AREA. IN ADDITION...A DROPSONDE RELEASED IN THE AREA HAD A SURFACE WIND OF 57 KT. THESE DATA SUGGEST THE INTENSITY REMAINS NEAR 55 KT. HANNA HAS BEEN STRUGGLING TO GENERATE PERSISTENT DEEP CONVECTION NEAR THE CENTER DUE TO SHEAR AND DRY AIR...ALTHOUGH THERE HAS BEEN A RECENT BURST WITHIN THE LAST COUPLE OF HOURS. WHILE THERE IS SOME POTENTIAL FOR A LITTLE ADDITIONAL STRENGTHENING...ALL BUT ONE OF THE INTENSITY MODELS KEEP HANNA JUST BELOW HURRICANE STRENGTH. STILL...THERE IS LITTLE DIFFERENCE BETWEEN A STRONG TROPICAL STORM AND A CATEGORY ONE HURRICANE...AND HANNA COULD REACH HURRICANE STRENGTH BEFORE MOVING INLAND OVER THE SOUTHEASTERN UNITED STATES IN ABOUT 24 HOURS.

HANNA IS BEING STEERED BY THE SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC RESULTING IN A MOTION TOWARD THE NORTHWEST OR 320/17. HANNA IS EXPECTED TO TURN TOWARD THE NORTH TODAY THEN NORTHEASTWARD TONIGHT AND TOMORROW AS IT ROUNDS THE WESTERN PERIPHERY OF THE RIDGE. THEREAFTER...HANNA IS EXPECTED TO RACE NORTHEASTWARD AND BECOME EXTRATROPICAL IN ABOUT 3 DAYS. TRACK MODELS HAVE BEEN TRENDING TOWARD THE WEST AND THE OFFICIAL FORECAST IS SHIFTED TO THE LEFT THROUGH 36 HOURS. HOWEVER...GIVEN HANNA'S LARGE SIZE...ONE SHOULD NOT FOCUS ON THE EXACT TRACK AS THE INCLEMENT WEATHER EXTENDS WELL BEYOND THE CENTER.



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