000
WTPZ44 KNHC 101432
TCDEP4
TROPICAL DEPRESSION NINE-E DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092009
800 AM PDT MON AUG 10 2009
 
AMSR-E AND TRMM MICROWAVE PASSES FROM A FEW HOURS AGO INDICATED THAT
THE DEEPEST CONVECTION IS BEING SHEARED TO THE SOUTHEASTERN SIDE OF
T.D. NINE-E...AND THE LOW-LEVEL CIRCULATION HAS BECOME A LITTLE
MORE ILL-DEFINED. AN ASCAT PASS FROM 0549 UTC CONFIRMED THAT THE
SYSTEM HAD MAXIMUM WINDS OF 30 KT...AND SINCE THE STRUCTURE OF THE
DEPRESSION HAS NOT IMPROVED SINCE THEN...THE INITIAL INTENSITY IS
KEPT AT 30 KT.

THE INTENSITY MODEL GUIDANCE CONTINUES TO SHOW A DOWNWARD TREND FROM
PREVIOUS RUNS. NORTHWESTERLY SHEAR DUE TO AN UPPER-LEVEL TROUGH
LOCATED NORTH OF THE DEPRESSION IS EXPECTED TO CONTINUE FOR THE
NEXT 24 HOURS...AND THE NEW OFFICIAL FORECAST DOES NOT SHOW THE
SYSTEM BECOMING A TROPICAL STORM UNTIL THAT TIME. THIS IS DELAYED
COMPARED WITH THE PREVIOUS FORECAST BUT IS STILL SOONER THAN
INDICATED BY THE SHIPS MODEL...WHICH SHOWS THE CYCLONE BECOMING A
TROPICAL STORM IN 48 HOURS. VERTICAL SHEAR IS EXPECTED TO ONCE
AGAIN INCREASE BY DAYS 4 AND 5...AND THE SYSTEM WILL BE MOVING OVER
MARGINALLY WARM WATERS BY THAT TIME. AS SUCH...THE MAXIMUM
INTENSITY IS CAPPED AT 40 KT WITH WEAKENING ANTICIPATED BY DAY 5.
THE GFS AND GFDL ACTUALLY LOSE THE VORTEX BEFORE THE END OF THE
FORECAST PERIOD...AND THERE IS SOME DOUBT THAT THE DEPRESSION WILL
LAST FIVE DAYS AS A TROPICAL CYCLONE.

THE INITIAL MOTION IS 275/08...AS THE DEPRESSION IS BEING STEERED BY
A MID-LEVEL RIDGE EXTENDING WEST-SOUTHWESTWARD FROM NORTHERN
MEXICO. THE MODEL SPREAD IS SMALL THROUGH 72 HOURS...WITH THE
EXCEPTION OF THE GFDL...WHICH TURNS THE DEPRESSION SOUTHWEST AND
DISSIPATES IT. SEVERAL MODELS ARE STILL SHOWING ANOTHER SYSTEM
DEVELOPING WEST OF THE DEPRESSION NEAR 138W IN A FEW DAYS...AND THE
MODEL CONSENSUS IS RESPONDING BY SHOWING A WEST-SOUTHWESTWARD TURN
BY DAY 5. THE OFFICIAL TRACK FORECAST IS ONLY SHIFTED SLIGHTLY
SOUTHWARD FROM THE PREVIOUS FORECAST AND LIES CLOSE TO THE MODEL
CONSENSUS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/1500Z 14.9N 123.1W    30 KT
 12HR VT     11/0000Z 15.1N 124.4W    30 KT
 24HR VT     11/1200Z 15.5N 126.1W    35 KT
 36HR VT     12/0000Z 15.9N 127.8W    35 KT
 48HR VT     12/1200Z 16.2N 129.7W    40 KT
 72HR VT     13/1200Z 16.5N 133.5W    40 KT
 96HR VT     14/1200Z 16.5N 137.0W    40 KT
120HR VT     15/1200Z 16.5N 141.0W    35 KT
 
$$
FORECASTER BERG