Tropical Depression SEVEN-E

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TROPICAL DEPRESSION SEVEN-E DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072007
200 AM PDT SUN JUL 22 2007
 
IT HAS BEEN QUITE A CHALLENGE TO LOCATE THE LOW-LEVEL CIRCULATION
OVERNIGHT.  USING CONVENTIONAL SATELLITE IMAGERY AS WELL AS A 0546
UTC TRMM PASS...THE CENTER IS ROUGHLY ESTIMATED NEAR THE NORTHEAST
EDGE OF THE DEEPEST CONVECTION.  THE DEPRESSION IS STILL IN ITS
ORGANIZATION STAGE...AND LACKS SIGNIFICANT BANDING FEATURES.  BASED
ON THE CURRENT SATELLITE PRESENTATION...THE INITIAL INTENSITY WILL
REMAIN AT 25 KT.
 
THE INITIAL MOTION IS ESTIMATED TO BE WEST-NORTHWEST AROUND 11 KT.
THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF
DAYS AS THE CYCLONE IS STEERED BY THE RIDGE TO THE NORTH.
THEREAFTER...MOST OF THE DYNAMICAL MODEL GUIDANCE IS IN AGREEMENT
IN A SLOWER MOTION AND A TURN TOWARD THE NORTHWEST ONCE THE RIDGE
WEAKENS.  THE TIMING...HOWEVER...OF WHEN THIS NORTHWEST TURN WILL
OCCUR IS WHERE THE TRACK UNCERTAINTY LIES.  THE OFFICIAL TRACK
FORECAST IS SIMILAR TO THE PREVIOUS FORECAST AND FOLLOWS MOST
CLOSELY WITH THE HWRF AND UKMET SOLUTIONS...WHICH TURN THE CYCLONE
NORTHWESTWARD AFTER 48 HOURS.
 
A SHEAR ANALYSIS FROM UW-CIMSS INDICATES AROUND 20-25 KTS OF
NORTHEASTERLY SHEAR CURRENTLY IMPINGING UPON THE CYCLONE...AS A
RESULT OF A STRONG UPPER-LEVEL HIGH OVER MEXICO.  THE SHEAR IS
EXPECTED TO PERSIST FOR THE NEXT COUPLE OF DAYS...WHICH WOULD SLOW
THE INTENSIFICATION PROCESS....AND THEN RELAX SOMEWHAT.  SEA
SURFACE TEMPERATURES ARE CURRENTLY 29C AND...BASED ON THE CURRENT
TRACK FORECAST...SHOULD REMAIN SUFFICIENTLY WARM TO SUSTAIN THE
CYCLONE THROUGH THE NEXT FIVE DAYS. THE OFFICIAL INTENSITY FORECAST
ANTICIPATES GRADUAL STRENGTHENING FOR THE NEXT THREE DAYS THEN
LEVELS OFF.  THIS IS CONSISTENT WITH BOTH THE SHIPS AND HWRF
GUIDANCE...BUT IS ABOVE THE GFDL AT DAYS FOUR AND FIVE...WHICH
TURNS THE CYCLONE NORTHWESTWARD SOONER INTO A HIGHER SHEARED
ENVIRONMENT.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0900Z 12.8N 106.0W    25 KT
 12HR VT     22/1800Z 13.2N 107.3W    30 KT
 24HR VT     23/0600Z 13.6N 108.8W    35 KT
 36HR VT     23/1800Z 13.8N 110.1W    40 KT
 48HR VT     24/0600Z 14.2N 111.0W    45 KT
 72HR VT     25/0600Z 15.5N 112.0W    50 KT
 96HR VT     26/0600Z 17.5N 113.5W    50 KT
120HR VT     27/0600Z 20.0N 116.0W    50 KT
 
$$
FORECASTER MAINELLI
 
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