000
AXPZ20 KNHC 221609
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT OCT 22 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 CYCLONIC CIRCULATION IN SW CARIBBEAN 
TO NW COAST OF COSTA RICA NEAR 10.5N86W TO 13N94W TO 10N104W 
WHERE IT HAS BROKEN AND TERMINATES...THEN BEGINS ANEW FROM LOW 
PRES NEAR 15.5N113.5W TO SECOND LOW NEAR 11N117W TO 08N123W 
WHERE IT TRANSITIONS TO ITCZ TO 06.5N130W TO BEYOND 08N140W. 
ISOLATED TO SCATTERED MODERATE CONVECTION NOTED FROM 07N TO 10N 
BETWEEN 82W AND 90W AND ALSO BETWEEN 107W AND 117W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 60 NM OF LINE 
22N108.5W TO 16N113W.

...DISCUSSION...
ALOFT...AN ELONGATED UPPER LEVEL TROUGH IS STRETCHED NEARLY E TO 
W ALONG 30N ACROSS N PORTIONS OF THE AREA...TO A MID LEVEL 
CYCLONE NEAR 32N139W. A ZONAL UPPER FLOW PATTERN PREVAILS S OF 
THIS TROUGHING TO 18-20N...WITH WEAK MID LEVEL TROUGHING 
OCCURRING BELOW THIS ZONAL FLOW...FROM 30N116W TO 19N126W. S OF 
THIS ZONAL FLOW...AN UPPER RIDGE EXTENDS W-SW TO E-NE ACROSS THE 
AREA FROM AN UPPER ANTICYCLONE NEAR 14N155W TO 18N128W...WHILE A 
SECOND RIDGE EXTENDED FROM 18N114W TO SE MEXICO. UPPER LEVEL 
EASTERLIES PREVAILED GENERALLY S OF 13-15N EXTENDING FROM THE 
FAR W CARIBBEAN AND CENTRAL AMERICA TO BEYOND 140W.

AT LOWER LEVELS...MONSOONAL FLOW PREVAILED 20 OF 20N AND E OF 
110W...WITH THE MONSOON TROUGH ANCHORED ON THE EVOLVING CYCLONIC 
CIRCULATION IN THE SW CARIBBEAN. N OF THE TROUGH...FRESH WINDS 
FUNNELING THROUGH THE CHIVELAS PASS INTO GULF OF TEHUANTEPEC 
CONTINUED THIS MORNING AT 20 TO 30 KT...WITH SEAS TO 10 FT...BUT 
WILL WEAKEN SLIGHTLY TO 20 TO 25 KT DURING THE DAY...BEFORE 
INCREASING AGAIN LATE TONIGHT BACK TO 20 TO 30 KT. GLOBAL MODELS 
SUGGEST WINDS INCREASING TO NEAR GALE FORCE BY LATE SUN/EARLY 
MON IN RESPONSE TO THE SW CARIBBEAN LOW LIFTING N INTO THE NW 
CARIBBEAN AND BACKING FLOW ACROSS THE W GULF OF MEXICO. 

A 1028 MB HIGH PRES CENTER WAS LOCATED NEAR 35N139W WITH RIDGE 
EXTENDING SE TO NEAR 23N114W. THIS WAS PRODUCING FRESH NE TRADES 
NEAR 20 KT BREEZE FROM 11N TO 21N W OF 128W WHICH WEAKEN BY MON 
AS HIGH PRES DRIFTS N AND WEAKENS IN RESPONSE TO SHARP UPPER 
LEVEL TROUGH MOVING INTO BASIN MON. PRESENT FRESH N WINDS N OF 
28N BETWEEN 123W AND 128W ARE ALSO EXPECTED TO DIMINISH BY THIS 
EVENING AS HIGH PRES MOVES N.

W PORTION OF THE EPAC MONSOON TROUGH HAS BROKEN FROM THE FAR E 
PORTION PAST 48 HOURS AND EXTENDED FROM A WEAK 1010 MB LOW PRES 
CENTER NEAR 18N112W SW TO THE ITCZ NEAR 07N125W. THIS SEGMENT OF 
THE TROUGH AND ASSOCIATED LOW WILL DRIFT W AND W-SW AND WEAKEN 
NEXT SEVERAL DAYS. 
 
$$
STRIPLING