Tropical Depression SEVEN-E

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TROPICAL DEPRESSION SEVEN-E DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072007
800 PM PDT SUN JUL 22 2007
 
THE DEPRESSION REMAINS VERY POORLY ORGANIZED THIS EVENING.  A SMALL
CLOUD SWIRL...WITH MODEST ATTENDANT CONVECTION...IS ROTATING WITHIN
A MUCH LARGER CYCLONIC GYRE.  LATEST DVORAK T-NUMBERS FROM TAFB AND
SAB CORRESPOND TO 30 KT...AND THAT REMAINS THE ADVISORY
INTENSITY...ALTHOUGH I SUSPECT THIS ESTIMATE IS A BIT GENEROUS.  

WHILE THE CLOUD SWIRL HAS BEEN MOVING NORTHWESTWARD OVER THE PAST
FEW HOURS...A LONGER-TERM REPRESENTATIVE MOTION IS 285/7.  THE
DEPRESSION IS SOUTH OF A WEAK MID-LEVEL RIDGE OF HIGH PRESSURE OVER
NORTHWESTERN MEXICO...WITH A MID-LEVEL TROUGH OVER NORTHEASTERN
MEXICO.  GLOBAL MODEL GUIDANCE IS IN GOOD AGREEMENT THAT THESE TWO
FEATURES WILL PROGRESS WESTWARD OVER THE NEXT FEW DAYS AROUND A
LARGE SCALE ANTICYCLONE CURRENTLY OVER THE CENTRAL UNITED STATES. 
AS THE MID-LEVEL TROUGH MOVES WESTWARD TO THE NORTH AND THEN
NORTHWEST OF THE TROPICAL CYCLONE...STEERING CURRENTS ARE EXPECTED
TO WEAKEN AND A SLOWER...MORE NORTHWARD TRACK SHOULD DEVELOP.  WITH
THE EXCEPTION OF ONE RIGHT OUTLIER...THE GFDN...AND ONE LEFT
OUTLIER...THE GFS ENSEMBLE MEAN...TRACK GUIDANCE IS IN PRETTY GOOD
AGREEMENT.  THE OFFICIAL FORECAST IS VERY SIMILAR TO THE PREVIOUS
ADVISORY...JUST NUDGED A LITTLE TO THE RIGHT OF THE PREVIOUS
FORECAST...BUT STILL TO THE LEFT OF THE MODEL CONSENSUS.  THE
MOTION OF THE DEPRESSION IS LIKELY TO BE ERRATIC UNTIL THE CORE
CIRCULATION BECOMES BETTER DEFINED.

STRONG NORTHEASTERLY SHEAR CONTINUES TO DISRUPT THE CONVECTIVE
ORGANIZATION...ALTHOUGH THE GLOBAL MODELS ARE UNANIMOUS IN
FORECASTING THIS SHEAR TO LESSEN OVER THE NEXT 36-48 HOURS. 
ASSUMING THE SYSTEM SURVIVES...AND IT SHOULD GIVEN ITS LARGE
CYCLONIC ENVELOPE...THERE WILL BE A GOOD OPPORTUNITY FOR
STRENGTHENING BETWEEN 36-72 HOURS.  IF THE TRACK FORECAST IS
CORRECT...THE CYCLONE WILL BE MOVING OVER COOLER WATERS BY DAY
4...WHEN A WEAKENING TREND IS EXPECTED.  THE SHIPS...GFDL...AND
HWRF MODELS ARE IN PRETTY GOOD AGREEMENT AND THE OFFICIAL FORECAST
REPRESENTS A BLEND OF THIS GUIDANCE.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0300Z 13.3N 107.6W    30 KT
 12HR VT     23/1200Z 13.6N 108.7W    30 KT
 24HR VT     24/0000Z 14.2N 109.7W    35 KT
 36HR VT     24/1200Z 14.9N 110.4W    40 KT
 48HR VT     25/0000Z 15.6N 110.9W    50 KT
 72HR VT     26/0000Z 17.5N 112.0W    60 KT
 96HR VT     27/0000Z 19.5N 114.5W    55 KT
120HR VT     28/0000Z 22.0N 118.0W    45 KT
 
$$
FORECASTER FRANKLIN
 
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