000
WTPZ41 KNHC 152038
TCDEP1
 
TROPICAL DEPRESSION SIX-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062011
200 PM PDT MON AUG 15 2011
 
A SMALL LOW PRESSURE SYSTEM...LOCATED NEAR THE INTERTROPICAL
CONVERGENCE ZONE ABOUT MIDWAY BETWEEN THE SOUTHERN TIP OF BAJA
CALIFORNIA AND THE HAWAIIAN ISLANDS...CONTINUES TO PRODUCE A
COMPACT AREA OF DEEP CONVECTION.  EASTERLY SHEAR WHICH HAS BEEN
IMPACTING THE SYSTEM HAS DECREASED TODAY...AND A SMALL BAND OF
CONVECTION HAS DEVELOPED AROUND THE SOUTHERN AND SOUTHWESTERN SIDE
OF THE CIRCULATION.  SATELLITE INTENSITY ESTIMATES ARE NOW T1.5 AND
T2.5 FROM TAFB AND SAB...RESPECTIVELY...AND THE SYSTEM IS THEREFORE
DESIGNATED AS A DEPRESSION AT THIS TIME.  AN ASCAT OVERPASS FROM
LAST NIGHT SUGGESTED THAT WINDS WERE NEAR 30 KT...AND THAT IS THE
INITIAL INTENSITY.
 
VERTICAL SHEAR IS FORECAST BY THE SHIPS GUIDANCE TO DECREASE BELOW
10 KT BETWEEN 12 AND 60 HOURS...WHICH WOULD GIVE THE DEPRESSION
SOME TIME TO STRENGTHEN.  HOWEVER...THE SYSTEM WILL ALSO BE MOVING
OVER A SOUTHWARD-PROTRUDING TONGUE OF COOLER WATERS ALONG 140W...IS
BOUNDED BY A VAST AREA OF STABLE AIR TO ITS NORTH...AND IS
INTERACTING WITH THE ITCZ...WHICH WOULD ALL ARGUE AGAINST
SIGNIFICANT INTENSIFICATION.  THE OFFICIAL FORECAST INDICATES
MODEST STRENGTHENING THROUGH 48 HOURS AND IS A LITTLE BELOW THE
STATISTICAL INTENSITY GUIDANCE.  IT SHOULD BE NOTED THAT THE
DEPRESSION IS A FAIRLY FRAGILE SYSTEM GIVEN ITS SMALL SIZE AND
MARGINALLY CONDUCIVE ENVIRONMENT...SO IT WOULD NOT BE SURPRISING AT
ALL IF IT DEGENERATED TO A REMNANT LOW AT SOME POINT WITHIN THE
5-DAY FORECAST PERIOD.
 
THE DEPRESSION IS MOVING TOWARD THE WEST WITH AN INITIAL MOTION OF
270/9 AND IS LOCATED ON THE SOUTHERN SIDE OF A NARROW EAST-
NORTHEAST TO WEST-SOUTHWEST ORIENTED MID-LEVEL RIDGE.  A BREAK IN
THE RIDGE IS FORECAST TO DEVELOP BETWEEN 130W AND 140W WITHIN 36 TO
48 HOURS.  HOWEVER...SINCE THE DEPRESSION IS NOT EXPECTED TO
STRENGTHEN SIGNIFICANTLY...IT IS MORE LIKELY TO BE STEERED BY THE
LOW- TO MID-LEVEL FLOW AND NOT BE SIGNIFICANTLY AFFECTED BY THE
TROUGH.  THERE IS QUITE A BIT OF SPREAD IN THE TRACK GUIDANCE WITH
THE GFS AND ECMWF BEING THE FASTEST AND FARTHEST SOUTH OF THE
MODELS.  WITH THE ASSUMPTION THAT THE SYSTEM WILL REMAIN ON THE
WEAK SIDE...THE OFFICIAL FORECAST IS A BLEND OF THOSE TWO MODELS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/2100Z 12.0N 132.3W   30 KT  35 MPH
 12H  16/0600Z 12.0N 133.3W   30 KT  35 MPH
 24H  16/1800Z 12.0N 134.7W   35 KT  40 MPH
 36H  17/0600Z 12.1N 136.4W   40 KT  45 MPH
 48H  17/1800Z 12.3N 137.9W   45 KT  50 MPH
 72H  18/1800Z 13.0N 140.5W   45 KT  50 MPH
 96H  19/1800Z 13.5N 144.5W   40 KT  45 MPH
120H  20/1800Z 13.5N 149.0W   35 KT  40 MPH
 
$$
FORECASTER BERG