Tropical Storm BERTHA
ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BERTHA DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008
1100 AM EDT FRI JUL 04 2008
THE CLOUD PATTERN OF BERTHA CONSISTS OF A COUPLE OF CLUSTERS OF
CONVECTION TO THE NORTH AND SOUTH OF THE CENTER EMBEDDED WITHIN A
LARGE CYCLONIC CIRCULATION IN THE LOW CLOUDS. A QUIKSCAT OVERPASS
THAT WAS RECEIVED JUST AFTER THE ISSUANCE OF THE PREVIOUS
ADVISORY...SUGGEST THAT THE MAXIMUM WINDS WERE AROUND 45 KT. THE
STRUCTURE OF THE CYCLONE HAS CHANGE LITTLE SINCE THAT TIME AND THE
LATEST DVORAK DATA T NUMBERS FROM SAB AND TAFB SUPPORT A 45 KT
INITIAL INTENSITY.
BERTHA WILL BE PASSING OVER SLIGHTLY COOLER WATERS DURING THE NEXT
24 HOURS...SO NO CHANGE IN INTENSITY IS EXPECTED IN THE NEAR TERM.
BETWEEN 24 AND 72 HOURS...CONDITIONS ARE EXPECTED TO BECOME
CONDUCIVE FOR GRADUAL STRENGTHENING AS SSTS INCREASE AND THE SHEAR
REMAINS LOW. MODELS SUGGEST THAT THE SHEAR COULD INCREASE
THEREAFTER...SO THE NEW FORECAST KEEPS THE INTENSITY JUST SHY OF
HURRICANE STRENGTH. HOWEVER....IT IS WORTH MENTIONING THAT THE
SHIPS...LGEM...AND GFDL MODELS FORECAST BERTHA TO BECOME A
HURRICANE IN 3-4 DAYS.
BERTHA IS MOVING WEST-NORTHWESTWARD AT A LITTLE FASTER
PACE...290/14. THE STORM SHOULD REMAIN ON THIS GENERAL HEADING
DURING THE NEXT 2-3 DAYS AS IT IS LOCATED SOUTH OF A MID-LEVEL
RIDGE OVER THE EASTERN ATLANTIC. THE GUIDANCE HAS CONTINUED TO
SHIFT WESTWARD...BUT THERE REMAINS TWO DISTINCT ENVELOPES...ONE
THAT CONSISTS OF THE HWRF AND GFDL THAT TURN THE CYCLONE
NORTHWESTWARD BEYOND DAY 3....AND THE OTHER WHICH KEEPS BERTHA
ON A MORE WEST-NORTHWEST TRACK. THE OFFICIAL FORECAST TRACK HAS
BEEN ADJUSTED WESTWARD TO REFLECT THE SHIFT IN THE GUIDANCE.
FORECAST POSITIONS AND MAX WINDS
INITIAL 04/1500Z 14.9N 29.7W 45 KT
12HR VT 05/0000Z 15.7N 32.1W 45 KT
24HR VT 05/1200Z 16.5N 35.6W 45 KT
36HR VT 06/0000Z 17.2N 39.2W 50 KT
48HR VT 06/1200Z 17.9N 42.9W 55 KT
72HR VT 07/1200Z 19.5N 49.5W 60 KT
96HR VT 08/1200Z 21.5N 54.5W 60 KT
120HR VT 09/1200Z 24.0N 59.0W 60 KT
$$
FORECASTER BROWN
NNNN