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Eastern Pacific Tropical Weather Discussion (Text)

000
AXPZ20 KNHC 222159
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC WED MAY 22 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 
2145 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH AXIS EXTENDS FROM CENTRAL COSTA RICA TO 11N91W TO 
LOW PRES NEAR 11N101W 1009 MB TO 09N119W TO 07N120W WHERE IT 
TRANSITIONS TO ITCZ AXIS...AND CONTINUES TO 11.5N131W TO 
05N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 
120 NM OF THE AXIS BETWEEN 84W-91W...AND ALSO WITHIN 120 NM S OF 
THE AXIS BETWEEN 94W-100W. SCATTERED MODERATE CONVECTION EXISTS 
WITHIN 180 NM S OF THE AXIS BETWEEN 115W-121W...WITHIN 60 NM OF 
THE AXIS BETWEEN 121W-125W AND ALSO WITHIN 60 NM OF THE AXIS 
BETWEEN 126W-129W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM 
S OF THE AXIS BETWEEN 130W-133W...AND ALSO WITHIN 30 NM OF THE 
AXIS BETWEEN 135W-137W

...DISCUSSION...

A 1032 MB HIGH CENTER IS LOCATED WELL NW OF THE DISCUSSION AREA 
AT 42N142W WITH A RIDGE EXTENDING SEWD INTO THE AREA THROUGH 
32N135W TO 25N126W AND CONTINUING SE TO NEAR 21N121W. A TIGHT 
PRES GRADIENT BETWEEN THE RIDGE AND LOW PRES OVER THE WESTERN 
U.S. IS RESULTING IN GALE FORCE WINDS N OF THE AREA NEAR 
THE CALIFORNIA COAST. ASSOCIATED NW-N WINDS OF 20-25 KT SEEP
S INTO THE AREA TO N OF 29N BETWEEN 119W-124W WHERE SEAS ARE 
IN THE 9-11 FT RANGE. A WEAKENING SURFACE TROUGH...REMNANTS OF  
FORMER T.S. ALVIN ARE OVER THE SW PORTION OF THE AREA FROM NEAR 
09N136W TO 13N130W. THE PRES GRADIENT BETWEEN AFOREMENTIONED 
RIDGE AND THIS TROUGH IS PRODUCING A SMALL AREA OF NE 20 KT 
WINDS FROM ROUGHLY 12N TO 16N BETWEEN 130W AND 136W...WHERE SEAS 
ARE TO 9 FT. OTHERWISE...MODERATE TO FRESH ANTICYCLONIC FLOW 
PREVAILS ACROSS THE AREA W OF 120W...WITH SEAS GENERALLY 7 TO 8 
FT IN MIXED NORTHERLY AND SW CROSS EQUATORIAL SWELL. THE 1032 MB 
HIGH WILL SLIDE W THROUGH FRI...HOWEVER THE TIGHT GRADIENT IS 
EXPECTED TO REMAIN NE OF THE AREA. WINDS ARE FORECAST TO BE 20 
KT OR LESS N OF 16N BETWEEN 113W-134W...AND ALSO N OF 12N W OF 
134W BY FRI AFTERNOON WITH SEAS TO 9 FT IN MIXED N AND NE SWELL. 
THE REMNANT TROUGH OF ALVIN WILL MOVE TO JUST W OF THE AREA FRI 
AFTERNOON WITH WINDS EXPECTED TO BE 20 KT OR LESS AND SEAS LESS 
THAN 8 FT IN THE FAR SW PORTION OF THE AREA. 

MONSOONAL FLOW HAS BECOME WELL ESTABLISHED ACROSS THE FAR 
EASTERN PACIFIC E OF 110W...WITH MODERATE SW TO W WINDS 
EXTENDING AS FAR N AS 11N BETWEEN 95W AND 110W. UPPER LEVEL 
RIDGING PREVAILS ACROSS THE AREA E OF ABOUT 110W AND IS 
PRODUCING A FAVORABLE ENVIRONMENT FOR SUSTAINED DEEP CONVECTION. 

A BROAD LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION IS FORECAST TO 
DEVELOP OVER THE SE PORTION OF THE AREA THROUGH FRI WHILE 
SHIFTING WWD. GLOBAL MODELS SUGGEST THAT EVENTUALLY A LOW PRES 
SYSTEM MAY EVOLVE FROM THIS AREA. PRESENTLY...A WEAK 1009 MB LOW 
IS ALONG THE MONSOON TROUGH AXIS AT 11N101W. SCATTERED STRONG 
CONVECTION IS WITHIN 45 NM EITHER SIDE OF LINE FROM 12N103.5W TO 
14N100W. SIMILAR CONVECTION SW OF LOW EXISTS FROM 08.5N TO 11N 
BETWEEN 101W AND 105W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS ELSEWHERE FROM 07N TO 14N BETWEEN 99W-106W. THE 
LOW IS CURRENTLY UNDER UPPER EASTERLY SHEAR...BUT IT HAS SOME 
POTENTIAL TO GRADUALLY DEVELOP OVER THE NEXT 48 HRS AS IT TRACKS 
W TO NW DIRECTION.                                    

NOTE...A GOES-E/GOES-13 ANOMALY OCCURRED LAST NIGHT PRIOR TO 
0400 UTC AND HAS IMPACTED THE FULL SUITE OF IMAGERY AVAILABLE 
FROM THIS SATELLITE...AND IS LIMITING CONFIDENCE IN SATELLITE 
INTERPRETATION ACROSS THE REGION BETWEEN APPROXIMATELY 60W AND 
100W. NESDIS ENGINEERS ARE WORKING ON RECOVERY EFFORTS AT THIS 
TIME. GOES-14 IS BEING ACTIVATED AND THE FIRST IMAGES ARE 
EXPECTED TO BECOME AVAILABLE AROUND 0500 UTC THU MAY 23. 

$$
AGUIRRE