000
WTPZ42 KNHC 200238
TCDEP2
 
TROPICAL DEPRESSION SEVENTEEN-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172013
800 PM PDT SAT OCT 19 2013
 
DEEP CONVECTION ASSOCIATED WITH THE AREA OF LOW PRESSURE LOCATED
SOUTH OF THE SOUTHERN COAST OF MEXICO HAS CONTINUED TO BECOME
BETTER ORGANIZED THIS EVENING.  RECENT MICROWAVE AND INFRARED
SATELLITE IMAGERY SHOWS AN INCREASE IN BANDING AROUND THE CENTER.
BASED ON A DVORAK T-NUMBER OF 2.0 FROM TAFB...ADVISORIES ARE BEING
INITIATED ON A TROPICAL DEPRESSION WITH AN INITIAL INTENSITY OF
30 KT.  ENVIRONMENTAL CONDITIONS CONSISTING OF WARM WATER...
A MOIST LOW- TO MID-LEVEL ATMOSPHERE...AND LOW VERTICAL WIND
SHEAR....SHOULD SUPPORT STRENGTHENING DURING THE NEXT COUPLE OF
DAYS.  NEARLY ALL OF THE INTENSITY GUIDANCE BRINGS THE CYCLONE
TO HURRICANE STRENGTH WITHIN 2 TO 3 DAYS...AND SO DOES THE NHC
FORECAST.  AFTER THAT TIME...INTERACTION WITH LAND AND SOME DRIER
MID-LEVEL AIR TO THE NORTHWEST OF THE CYCLONE COULD CAUSE SOME
WEAKENING.  THE INTENSITY FORECAST AT DAYS FOUR AND FIVE IS
HIGHLY UNCERTAIN AS IT IS CONTINGENT UPON HOW MUCH THE CYCLONE
INTERACTS WITH LAND.
 
THE DEPRESSION IS MOVING NORTHWESTWARD OR 325 DEGREES AT 7 KT.
A SHORTWAVE TROUGH MOVING ACROSS NORTHERN MEXICO IS EXPECTED TO
MAINTAIN ENOUGH OF A WEAKNESS IN THE RIDGE TO ALLOW FOR THE
CYCLONE TO MOVE SLOWLY NORTHWESTWARD DURING THE NEXT COUPLE OF
DAYS.  BEYOND THAT TIME...THERE IS A HIGHER THAN NORMAL AMOUNT OF
UNCERTAINTY IN THE TRACK FORECAST.  THE GFDL AND HWRF SHOW THE
SYSTEM TURNING NORTHWARD...THEN NORTHEAST AND MAKING LANDFALL ALONG
THE SOUTHERN COAST OF MEXICO.  THE REMAINDER OF THE GUIDANCE...
INCLUDING THE GFS AND ECMWF MODELS...INDICATE THAT THE TROUGH OVER
THE EASTERN U.S. WILL SLIDE EASTWARD WITH A RIDGE BUILDING OVER THE
WEST-CENTRAL UNITED STATES.  THIS WOULD CAUSE THE CYCLONE TO TURN
BACK WESTWARD LATER IN THE PERIOD.  THE NHC TRACK BRINGS THE
CYCLONE VERY NEAR THE SOUTHERN COAST OF MEXICO IN ABOUT 3 DAYS...
THEN SHOWS IT TURNING WESTWARD OUT OF RESPECT FOR THE GFS AND
ECMWF SOLUTIONS.  
 
BASED ON THIS FORECAST...THE GOVERNMENT OF MEXICO HAS ISSUED A
TROPICAL STORM WATCH FOR A PORTION OF THE SOUTHERN COAST OF MEXICO. 
A HURRICANE WATCH MAY BE REQUIRED FOR A PORTION OF THE COAST ON
SUNDAY. HEAVY RAINFALL FROM THIS SYSTEM WILL LIKELY SPREAD
NORTHWARD INTO SOUTH-CENTRAL MEXICO DURING THE NEXT SEVERAL
DAYS...AND THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS
AND MUD SLIDES.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 14.0N 100.5W   30 KT  35 MPH
 12H  20/1200Z 14.5N 101.0W   40 KT  45 MPH
 24H  21/0000Z 15.2N 101.6W   50 KT  60 MPH
 36H  21/1200Z 15.8N 101.9W   60 KT  70 MPH
 48H  22/0000Z 16.1N 101.9W   65 KT  75 MPH
 72H  23/0000Z 16.7N 101.5W   70 KT  80 MPH
 96H  24/0000Z 17.1N 101.9W   60 KT  70 MPH
120H  25/0000Z 17.0N 103.7W   60 KT  70 MPH
 
$$
FORECASTER BROWN