000
AXPZ20 KNHC 241608
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 24 2011

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 
1500 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM SW CARIBBEAN ACROSS N COSTA RICA TO 
12N92W TO 07.5N105W WHERE IT BREAKS...THEN RESUMES FROM 21N116W 
TO LOW PRES CENTER 1009 MB AT 18N116W TO LOW PRES 1009 MB AT 
13N119W TO 09N125W...THEN TRANSITIONS TO ITCZ CONTINUING TO 
07N130W TO 07N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 
120 NM OF AXIS FROM 122W TO 136W.

...DISCUSSION...
SHARP UPPER LEVEL TROUGH EXTENDS FROM 36N127W TO 20N139W. UPPER 
LEVEL RIDGES ARE ANCHORED ACROSS THE TROPICS BOTH E AND W OF 
THIS TROUGH...ALONG 154W AND 112W. AN ELONGATED VORT LOBE WITHIN 
THE SW PORTION OF THE UPPER TROUGH IS SWINGING SE WITHIN THE 
TROUGH AND IS FORECAST TO DIG INTO THE WEAKNESS BETWEEN THE TWO 
RIDGES..TO 10N135W BY THU...AS THE EASTERN RIDGE ALONG 112W 
EXPANDS WWD. LOW LEVEL REPERCUSSIONS OF THIS PATTERN WILL BE TO 
MAINTAIN MODEST SURFACE RIDGE ACROSS N AND NW PORTIONS THROUGH 
MID WEEK...WHILE LOWER TROPOSPHERIC ELY STEERING FLOW WILL 
BECOME ENHANCED S OF 15N AND INDUCE A PROGRESSIVE WWD MOTION OF 
FEATURES ACROSS THE TROPICS NEXT SEVERAL DAYS. 

AT THE SURFACE...
HIGH PRES CENTER 1032 MB N OF BASIN NEAR 43N141W IS PROMOTING A 
MODEST PRES GRADIENT JUST NW OF WEAK SURFACE TROUGH FROM 32N125W 
TO 26N125W...YIELDING NE WINDS TO 20 KT N OF 28N W OF 133W. PRES 
GRADIENT S OF HIGH AND ITCZ ALSO PRODUCING FRESH NE TO E TRADES 
FROM 10N TO 19N W OF 133W. MODEL GUIDANCE SHIFTS HIGH PRES 
CENTER E THEN SLIGHTLY SE THROUGH MID WEEK WHILE WEAKENING... 
AND FRESH TRADES EXPECTED TO DIMINISH. ASSOCIATED SEAS BUILD TO 
8-11 FT UNDER MIX OF NE WIND SWELL AND NW SWELLS BY TUE. 

WITH TROPICAL STORM RINA GRADUALLY INTENSIFYING ACROSS THE NW 
CARIBBEAN AND MOVING SLOWLY NW...STRONG N WINDS ARE EXPECTED TO 
CONTINUE CROSSING CHIVELAS PASS THROUGH THE GULF OF TEHUANTEPEC 
THEN TURNING SW AND DOWNSTREAM TOWARDS 13N100W. RECENT MODEL 
GUIDANCE HAS BECOME UNANIMOUS OVERNIGHT...AND INDICATE A GALE 
EVENT WILL COMMENCE TONIGHT THROUGH TUE MORNING ACROSS 
TEHUANTEPEC...BEFORE DIMINISHING TO BELOW GALE FORCE TUE 
AFTERNOON. WITH RINA EXPECTED TO REMAIN ACROSS THE NW CARIBBEAN 
AND YUCATAN AREA FOR THE NEXT FEW DAYS...THIS MAY BE SUFFICIENT 
FORCING TO COMBINE WITH LATE NIGHT DRAINAGE FLOW ACROSS 
TEHUANTEPEC TO REACH NEAR GALES BEFORE SUNRISE FOR THE NEXT FEW 
DAYS. THUS RINA MAY INDIRECTLY INFLUENCE THIS GAP WIND EVENT 
UNTIL IT EXITS THE REGION. 
 
$$
STRIPLING