000
AXPZ20 KNHC 161602 RRA
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC FRI OCT 16 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM  
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.               

...SPECIAL FEATURES...

TROPICAL DEPRESSION NINETEEN-E IS CENTERED NEAR 9.7N 125.2W AT 
1500 UTC MOVING WEST OR 265 DEGREES AT 14 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 
KT WITH GUSTS TO 35 KT. FIRST VISIBLE IMAGERY SHOWS WHAT APPEARS 
TO BE NEW BANDING FEATURES REDEVELOPING OVER THE NW SEMICIRCLE 
OF THE DEPRESSION. THEY CONSIST OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION WITHIN 30 NM OF A LINE FROM 11N126W TO 13N126W 
TO 15N124W. SIMILAR ACTIVITY IS WITHIN 30 NM OF 12N128W
...AND WITHIN 45 NM OF 10N128W. SCATTERED STRONG CONVECTION IS 
WITHIN 120 NM OF CENTER IN THE S SEMICIRCLE...AND WITHIN 30 NM 
OF THE CENTER IN THE N SEMICIRCLE. AN UPPER LEVEL ANTICYCLONE IS 
OBSERVED TO THE NE OF THE DEPRESSION AT 15N123W. THE DEPRESSION 
IS FORECAST TO INTENSIFY TO A TROPICAL STORM BY SAT MORNING NEAR 
9.6N 129.0W...AND CONTINUE TO GRADUALLY INTENSIFY AS IT MOVES 
WESTWARD. IT IS EXPECTED TO REACH MINIMAL HURRICANE INTENSITY 
NEAR 10.9N 135.0W BY EARLY ON SUN. PLEASE SEE LATEST FORECAST 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE 
DETAILS ON TROPICAL DEPRESSION NINETEEN-E. 

GULF OF TEHUANTEPEC...GALE FORCE N-NE WINDS ARE FUNNELING ACROSS 
THE GULF OF TEHUANTEPEC WITH SEAS IN THE RANGE OF 10-13 FT AS 
SUGGESTED BY A RECENT ALTIMETER PASS. VISIBLE IMAGERY SHOWS A 
RATHER LARGE ARC CLOUD RACING SOUTHWARD AHEAD OF THE WIND SURGE 
ROUGHLY ALONG 10N BETWEEN 91W-99W. A TIGHT PRESSURE GRADIENT 
BETWEEN A BUILDING RIDGE OVER THE GULF OF MEXICO AND NE MEXICO 
AND TROPICAL WAVES BOTH E AND W OF TEHUANTEPEC WILL ALLOW FOR 
MINIMAL GALE FORCE WINDS TO CONTINUE THROUGH SUN NIGHT...WITH 
WINDS EXPECTED TO LESSEN TO JUST BELOW GALE FORCE SUN MORNING. 
WAVE MODEL GUIDANCE SUGGESTS SEAS IN THE 10-14 FT RANGE 
THROUGHOUT THE DURATION OF THIS EVENT. 

...TROPICAL WAVES...                                             

A TROPICAL WAVE AXIS IS ALONG 101W FROM 07N TO 15N..WITH MOTION 
OF ABOUT 10 KT. SCATTERED MODERATE CONVECTION IS SEEN WITHIN 
120 NM W OF THE WAVE FROM 04N-08N.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH AXIS EXTENDS FROM ALONG NW COLOMBIA TO 09N79W 
TO 11N90W TO 09N98W TO 08N106W TO 09N114W. THE ITCZ AXIS EXTENDS 
FROM 07N112W TO 08N140W. SCATTERED STRONG CONVECTION IS NOTED 
FROM 11N-15N BETWEEN 91W-95W. SCATTERED MODERATE CONVECTION IS 
WITHIN 120 NM N OF THE TROUGH BETWEEN 86W-89W...AND S OF THE  
TROUGH WITHIN 30 NM OF A LINE FROM 07N91W TO 07N94W TO 08N96W.

...DISCUSSION... 

A 1017 MB HIGH PRES CENTERED NEAR 26N136W EXTENDS A RIDGE SE 
THROUGH 22N124W AND TO NEAR 20N115W. TO THE N OF THE RIDGE 
AXIS...A TROUGH EXTENDS FROM 30N121W TO NEAR 28N129W. THE  
PRESSURE GRADIENT BETWEEN THE RIDGE TO THE N AND THE ITCZ AND 
TROPICAL DEPRESSION NINETEEN-E TO THE S IS RESULTING IN MAINLY 
MODERATE TRADE WINDS...WITH 20 TO 25 KT WINDS WITHIN 150 NM N OF 
TROPICAL DEPRESSION NINETEEN-E WITH SEAS 8-10 FT. A WEAKENING 
COLD FRONT OVER THE FAR NW PORTION WILL DISSIPATE AS IT REACHES 
A POSITION FROM NEAR 32N129W TO 26N137W AND STATIONARY TO 
25N140W BY EARLY ON SAT...AND TO A DISSIPATING FRONTAL TROUGH 
FROM 32N124W TO 26N140W BY EARLY ON SUN. SEAS OF 8-9 FT IN NW 
SWELL BEHIND THE FRONT ARE FORECAST TO BUILD TO 10 FT BY EARLY 
SAT...AND DIMINISH TO 8 FT BY EARLY ON SUN NW OF A LINE FROM 
32N127W TO 15N140W. STRONGER HIGH PRESSURE WILL THEN BUILD SE 
ACROSS THE CENTRAL AND WESTERN PORTIONS OF THE AREA SAT 
AFTERNOON THROUGH SUN...WITH THE INDUCED PRESSURE GRADIENT 
BETWEEN IT AND TROPICAL CYCLONE NINETEEN-E EXPANDING THE 
AREA OF 20-33 KT WINDS AROUND THE TROPICAL CYCLONE.

CROSS-EQUATORIAL SW SWELL WILL KEEP SEAS IN THE 7-9 FT RANGE S 
OF 06N BETWEEN 91W AND 129W THROUGH SAT MORNING. THIS SWELL WILL 
SUBSIDE...WITH SEAS LESS THAN 8 FT EXPECTED BY SUN MORNING. 
DESPITE THE SUBSIDING SEAS...A NEW BATCH OF SW SWELL WITH 
PERIODS IN THE 19-21 SECOND RANGE...WILL REACH THE GALAPAGOS 
ISLANDS ON SAT MORNING AND THE PACIFIC COAST S OF CABO 
CORRIENTES MEXICO ON SUN MORNING. THIS LONG-PERIOD SWELL COULD 
MAKE FOR DANGEROUS CONDITIONS ENTERING AND EXITING PORTS AND 
WILL INCREASE THE THREAT OF RIP CURRENTS.

A TROPICAL WAVE IS ANALYZED JUST E OF THE AREA OVER HONDURAS AND 
NICARAGUA NEAR 85W. CONVECTION ASSOCIATED WITH THE WAVE IS 
MAINLY CONFINED TO JUST N AND NE OF HONDURAS AND NICARAGUA.    
THE WAVE WILL TRACKS WESTWARD UNDER AN UPPER RIDGE AXIS THROUGH 
THE NEXT 24-48 HOURS. AN AREA OF FRESH SW WINDS IS EXPECTED TO 
BUILD ON THE SE SIDE OF THE WAVE OVER THE WEEKEND...WITH 7-9 FT 
SEAS EXPECTED TO COINCIDE WITH THESE WINDS. ENERGY FROM THE WAVE 
IN COMBINATION WITH THE MONSOONAL TROUGH GYRE PRESENT OVER THE 
FAR EASTERN PORTION OF THE AREA COULD LEAD TO THE FORMATION OF A 
LOW PRESSURE SYSTEM TO THE SE OF THE GULF OF TEHUANTEPEC OVER 
THE NEXT 48 HOURS.

$$ 
AGUIRRE