000
AXPZ20 KNHC 110936
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAY 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

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

MONSOON TROUGH EXTENDS FROM 09N84W TO 10N100W TO 08N104W...THEN 
THE ITCZ CONTINUES TO 05N120W TO 03N130W TO 02N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS FROM 02N TO 07N BETWEEN 
88W AND 94W. SIMILAR CONVECTION IS ALSO NOTED FROM 05N TO 12N 
BETWEEN 96W AND 117W.

ALOFT...MIDDLE TO UPPER CYCLONE SPINNING NEAR 28N143W WILL LIFT 
NE CLIPPING THE FAR NW PART OF THE FORECAST AREA TODAY. A 
VIGOROUS CUT OFF LOW IS OVER WEST TEXAS. IN BETWEEN...THERE IS A 
BROAD RIDGE WITH AXIS ROUGHLY ALONG 126W THAT DOMINATES MOST OF  
OF THE N WATERS. A SECOND BROAD RIDGE ANCHORED ON AN UPPER 
ANTICYCLONE NEAR 13N90W COVERS THE WATERS E OF 110W AND EXTENDS 
E INTO THE SW CARIB. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH 
THIS FEATURE IS HELPING TO INDUCE CONVECTION ALONG THE MONSOON 
TROUGH E OF 117W. 

AT THE LOWER LEVELS...A 1032 MB HIGH PRES CENTER WELL N OF AREA 
NEAR 44N132W WILL CONTINUE TO SHIFT NE AND AWAY FROM THE 
AREA...LEAVING A GRADUALLY RELAXING PRES GRADIENT ACROSS N 
PORTIONS OF THE AREA. HOWEVER...STRONG TO GALE FORCE WINDS 
PREVAILING OFFSHORE OF CALIFORNIA HAVE PRODUCE N AND NW SWELL 
THAT CONTINUES TO INVADE THE N WATERS...WITH SEAS TO 11 FT 
MAINLY N OF 27N AND W OF 120W. THIS SWELL EVENT WILL CONTINUE TO 
PROPAGATE SWD TODAY AND DECAY NEXT FEW DAYS...WITH SEAS LESS 
THAN 8 FT BY LATE SAT. OTHERWISE...NE WINDS AROUND 20 KT ARE 
FOUND ACROSS THE FAR NW CORNER OF THE AREA NW OF A LINE FROM 
30N135W TO 27N140W. LIGHT TO MODERATE NE TRADES ARE FOUND S OF 
THE RIDGE ACROSS THE TROPICS...WHILE LIGHT TO MODERATE MONSOONAL 
FLOW GENERALLY PREVAILS S OF THE MONSOON TROUGH E OF 110W. A 
COUPLE OF LOW LEVEL CYCLONIC CIRCULATIONS ARE NOTED ALONG THE 
MONSOON TROUGH...ONE IN THE VICINITY OF 08N112W AND A SECOND IN 
THE VICINITY OF 08N104W. MOST RECENT SCATTEROMETER PASSES SHOWED 
SW TO W WINDS NEAR 20 KT BLOWING INTO THESE LOW LEVEL CYCLONIC 
CIRCULATIONS. GLOBAL MODELS ARE NOT IN AGREEMENT WITH THE 
EVOLUTION OF THESE FEATURES. THE GFS IS MORE AGGRESSIVE TRYING 
TO DEVELOP A TROPICAL CYCLONE WHILE THE UKMET KEEPS A WEAK LOW 
PRES SYSTEM MOVING NW DURING THE NEXT FEW DAYS. THE FORECAST 
FOLLOWS THE UKMET SOLUTION. THE GFS MODEL IS PERHAPS SHOWING 
CONVECTIVE FEEDBACK. HOWEVER...IT IS THE TIME OF THE YEAR TO SEE 
THE FIRST SIGNS OF TROPICAL DEVELOPMENT ACROSS THIS AREA. MAY 15 
MARKS THE BEGINNING OF THE TROPICAL SEASON IN THE EASTERN NORTH 
PACIFIC. LONG-TERM AVERAGES OF TROPICAL STORMS...HURRICANES AND 
MAJOR HURRICANES IN THIS BASIN ARE 15...9...AND 4 RESPECTIVELY. 

A TROUGH MOVING ACROSS THE WESTERN GULF OF MEXICO INTO THE 
YUCATAN PENINSULA WILL CONTRIBUTE TO DEVELOP A WEAK TEHUANTEPEC 
EVENT BY SUN. 

$$
GR