000
AXPZ20 KNHC 100233
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU OCT 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION NARDA AT 16.5N 128.6N AT 0300 UTC MOVING
W-SW AT 2 KT.  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 LATE TONIGHT/EARLY THU. REFER TO NARDA FORECAST ADVISORY
UNDER WMO/AWIPS HEADERS WTPZ24 KNHC/ MIATCMEP4 FOR ADDITIONAL
DETAILS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 09N84W TO 10N100W TO LOW PRES 1009
MB AT 14N101W TO LOW PRES 1008 MB AT 13N112W TO 07N120W TO
08N125W THEN RESUMES FROM 15N129W TO BEYOND 11N140W.  SCATTERED
MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM NE SEMICIRCLE
OF LOW PRES AT 14N101W AND WITHIN 300 NM NW OF AXIS FROM 112W TO
120W.  SCATTERED MODERATE ISOLATED STRONG CONVECTION S OF AXIS
TO 05N E OF 87W. 
 
...DISCUSSION...
DEEP LAYER TROUGH EXTEND FROM UPPER LEVEL CYCLONE AT 37N117W TO 
32N117W TO 26N130W TO BEYOND 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 19N99W 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 1030 MB
HIGH PRES AT 37N145W TO 24N118W. 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