000
AXPZ20 KNHC 092141
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED OCT 09 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION NARDA AT 16.9N 128.N AT 2100 UTC STATIONARY.
MAXIMUM SUSTAINED WIND 30 GUSTING TO 40 KT WITH CENTRAL SURFACE
PRES OF 1007 MB.  NARDA WEAKENS AS IT DRIFT W OVER COOL WATERS
AND IMMERSED IN VERY DRY AIR MASS WHICH HAS TAKEN AWAY MOST 
CONVECTION.  NARDA EXPECTED TO BECOME REMNANT LOW PRES TONIGHT.
REFER TO NARDA FORECAST ADVISORY UNDER WMO/AWIPS HEADERS WTPZ24
KNHC/ MIATCMEP4 FOR ADDITIONAL DETAILS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 08N83W TO 09N90W TO LOW PRES 1009 MB
AT 14N100W TO LOW PRES 1008 MB AT 14N115W TO 07N124W THEN RESUMES
FROM 14N131W TO BEYOND 11N140W.  SCATTERED STRONG CONVECTION
WITHIN 150 NM NE SEMICIRCLE OF LOW PRES AT 14N100W AND WITHIN
300 NM NE OF AXIS FROM 11W-122W.  SCATTERED MODERATE ISOLATED
STRONG CONVECTION S OF AXIS TO 04N E OF 92W. 
 
...DISCUSSION...
DEEP LAYER TROUGH EXTEND FROM UPPER LEVEL CYCLONE AT 37N119W TO 
32N117W TO 26N128W TO 29N140W.  LAID DOWN TROUGH BRINGS QUASI-
ZONAL FLOW OF DRY STABLE AIR MASS ACROSS BASIN N OF 20N AND.
VERY DRY AIRMASS ALSO S OF 20N W OF 130W.  WELL DEFINED
ANTICYCLONE AT 16N98W ANCHORS BROAD RIDGE THAT EXTENDS ALONG 15N
TO 129W AND EASTWARD INTO CARIBBEAN SEA.  RIDGE BRINGS ABUNDANT
TROPICAL MOISTURE OVER E PAC ALONG MONSOON TROUGH.  WITH TWO
EMBEDDED LOW PRES CENTERS EMBEDDED IN MONSOON TROUGH...ITS ONLY
A QUESTION OF WHICH ONE WILL DEVELOP INTO TROPICAL CYCLONE. 
BOTH HAVE PLENTY OF TROPICAL MOISTURE...MECHANICAL UPLIFT...WARM
SEA SURFACE TEMPERATURE AND VORTICITY TO BUILD.  NEVERTHELESS 
GUIDANCE FOCUSES ON THE EASTERNMOST ONE DUE TO MUCH FAVORABLE
UPPER LEVEL CONDITIONS.  CLOSENESS TO ANTICYCLONE PROVIDES
BETTER DIVERGENT ANTICYCLONIC OUTFLOW.  

ELSEWHERE AT THE SURFACE...RIDGE EXTENDS FROM A HEALTHY 1035 MB
HIGH PRES AT 40N144W TO 22N110W. MODERATE TO FRESH NE TRADES ON 
SE PERIPHERY OF ANTICYCLONE SPIKE HIGHER BY SMALL AREA OF STRONG
NE BREEZE ASSOCIATED WITH DEPRESSION NARDA.  

HIGH PRES DRIFT E TIGHTENING PRES GRADIENT WITH SURFACE TROUGH
OVER BAJA CALIFORNIA AND INCREASING WINDS OVER COASTAL SECTION
OF W COAST AND GULF OF CALIFORNIA N OF 29N.  GRADIENT RELAXES
THU AND WINDS DIMINISH TO A LIGHT BREEZE.  SEAS NEVER REACH TO
8 FT. 

WALLY BARNES