000
AXPZ20 KNHC 031614
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT NOV 03 2012

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 
1515 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ROSA AT 12.7N 120.4W AT 1500 UTC MOVE W AT 4 KT. 
CENTRAL PRES 1006 MB.  MAXIMUM SUSTAINED WIND 35 GUSTS TO 45 KT. 
CONTINUED WESTERLY SHEAR HAS RESTRICTED ITS NUMEROUS MODERATE TO 
STRONG CONVECTION TO THE E QUADRANT AND SEPARATING FROM CENTER.  
ROSA EXPECTED TO DRIFT W-NW AND CONTINUE TO WEAKEN THROUGH MON 
...BECOMING POST-TROPICAL A REMNANT LOW PRES LATE TONIGHT.  SEE 
LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/ WMO HEADERS MIATCMEP2 
/ WTPZ22 KNHC FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N84W TO 08N94W TO 14N108W THEN 
RESUMES FROM T.S. ROSA TO 09N125W.  ITCZ EXTENDS FROM 09N126W TO 
07N133W TO 09N140W.  SCATTERED MODERATE CONVECTION WITHIN 60 NM 
S OF AXIS E OF 86W.  SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 90 NM OF AXIS W OF 130W.

...DISCUSSION...
UPPER LEVEL ANTICYCLONE 26N138W BRINGS DRY STABLE AIR MASS INTO 
BASIN N OF 220N W OF 125W WHILE DEEP TROUGH FROM 32N106W TO 
12N130W EXTENDS DRYNESS ALONG AND WITHIN 300 NM E OF ITS AXIS.   
STRONG WESTERLIES ALSO IMPACTING T.S. ROSA WITH RAPIDLY 
DECREASING CONVECTION AS DRY AIR ENTRAINS INTO CIRCULATION AND 
STRONG SHEAR SEPARATES LOW LEVEL CENTER FROM MAIN CONVECTION 
OUTBURST.  DEVELOPING LOW PRES NEAR 15N110W ALSO FEEL SHEAR BUT 
STILL HAS ABUNDANT MOISTURE.  

...ELSEWHERE AT THE LOWER LEVELS...
SURFACE HIGH PRES AT 28N135W 1022 MB MAINTAINS GOOD PRES 
GRADIENT WITH FRESH TRADES ON ITS SOUTHERN PERIPHERY.  GRADIENT 
EASES AS ROSA WEAKENS...SO TRADES FADE AWAY WITHIN NEXT TWO 
DAYS.  DEVELOPING LOW PRES AT 15N110W MOVES N INTO HOSTILE UPPER 
LEVEL ENVIRONMENT AS SHEAR REMAINS STRONG...AND COLDER SEA 
SURFACE TEMPERATURES WITH LITTLE CHANCE OF HAVING A SIGNIFICANT  
INTENSIFICATION...ALBEIT STILL HOLDING ITS OWN UNDER UNFAVORABLE 
CONDITIONS. 

GULF OF MEXICO COLD FRONT WILL INTRODUCE COLDER AIR MASS OVER 
BAY OF CAMPECHE WHICH IS EXPECTED TO SEEP THROUGH CHIVELAS PASS 
INTO GULF OF TEHUANTEPEC BY 48 HOURS.  EXPECT N WINDS TO 
INCREASE TO A FRESH BREEZE MON AND INCREASE THEREAFTER.

$$
WALLY BARNES