000
AXPZ20 KNHC 092158
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 09N88W 1009 MB TO 
10N114W TO 08N120W....WHERE IT TRANSITIONS TO ITCZ... CONTINUING 
ON TO 04N136W TO BEYOND 04N140W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 60 NM N AND 270 NM S OF MONSOON TROUGH 
FROM 88W TO 120W. SCATTERED MODERATE ISOLATED  STRONG CONVECTION 
NOTED WITHIN 90 NM EITHER SIDE OF ITCZ W OF 121W. 

...DISCUSSION...
AT UPPER LEVELS...A FLATTENING TROUGH-RIDGE-TROUGH PATTERN 
CONTINUES ACROSS THE AREA THIS AFTERNOON...N OF 20N...AND 
CONTINUES TO SHIFT VERY SLOWLY EWD. THE MIDDLE/UPPER TROUGH W OF 
THE AREA YESTERDAY HAS WEAKENED AND SHIFTED NE TO ALONG 140W... 
WITH UPPER TROUGH EXTENDING SE TO NEAR 08N134W. A DEEP LAYERED 
TROUGH SWEEPING N OF THE HAWAIIAN ISLANDS IS ACTING TO FORCE THE 
AFOREMENTIONED TROUGH NE ACROSS BACKSIDE OF SHORTWAVE RIDGE 
ALONG 125W. CUT OFF LOW ACROSS THE DESERT SW OF THE U.S. HAS 
MOVED SLOWLY SE PAST 24 HOURS AND IS NOW CENTERED OVER FAR NRN 
MEXICO NEAR 30N110W AND IS IGNITING WIDESPREAD CONVECTION WITHIN 
240 NM OF CENTER ACROSS NRN SEMICIRCLE AND E QUADRANT. S OF 20N 
E OF 125W...UPPER RIDGING PREVAILS TO 85W AS VERY ACTIVE 
CONVECTION NEAR THE MONSOON TROUGH AND ITCZ CONTINUE TO AID IN 
MAINTAINING DIVERGENT FLOW ALOFT. 

A 1036 MB HIGH HAS SHIFTED ENE IN THE PAST 24 HOURS...AND WAS 
LOCATED NNW OF THE AREA NEAR 41N142W...WITH RIDGE EXTENDING SE 
TO NEAR 16N105W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER 
PRES ALONG CALIFORNIA AND THE NORTHERN BAJA CALIFORNIA PENINSULA 
IS RESULTING IN AN AREA OF 20 KT NLY WINDS NW OF LINE 30N128W TO 
23N140W. THIS WEATHER PATTERN AND CONDITIONS WILL PERSIST 
THROUGH LATE THU WITH INCREASING NLY SWELL ON THU. THE PRES 
GRADIENT ALONG THE SOUTHERN PERIPHERY OF THE RIDGE HAS DECREASED 
AND THE NE TRADES ARE LESS THAN 20 KT N OF THE ITCZ. LATE 
MORNING AND EARLY AFTERNOON SCATTEROMETER DERIVED WINDS INDICATE 
THAT MONSOON FLOW S OF THE TROUGH HAS BEGUN TO INCREASE...AND 
WAS 15-20 KT BETWEEN 97W AND 113W...RESULTING SOME OF THE 
STRONGER CONVECTION DESCRIBED ABOVE. NO SIGNIFICANT CHANGES ARE 
EXPECTED IN THIS OVERALL WEATHER SCENARIO INTO THE WEEKEND AS 
HIGH PRES WILL REMAIN WELL N AND NW OF THE AREA.  

$$
STRIPLING