000
AXPZ20 KNHC 051556
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 05 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH ANALYZED FROM NW COLOMBIA MEANDERING W ACROSS 
CENTRAL AMERICA AND ADJACENT SW CARIBBEAN WATERS TO NEAR 11N85W 
TO 06.5N98W TO 06N102W...THEN TRANSITIONS TO ITCZ AND CONTINUES 
ON TO 07N114W TO 03N121W TO BEYOND 03N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION PREVAILS S OF MONSOON TROUGH TO 02N E 
OF 96W...AND WITHIN 150 NM S OF AXIS BETWEEN 96W AND 102W. 
SCATTERED MODERATE CONVECTION NOTED WITHIN 150 NM S OF ITCZ AXIS 
BETWEEN 102W AND 108W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION NOTED WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 113W 
AND 130W.

...DISCUSSION...
N OF 28N AND THE DISCUSSION AREA...A VERY BROAD OMEGA BLOCKING 
PATTERN STRADDLES BOTH SIDES OF N AMERICA...CENTERED ON AN UPPER 
LEVEL RIDGE ALONG ABOUT 92W. SOUTHERN STREAM IMPULSES CONTINUE 
TO MOVE SLOWLY UNDERNEATH THE RIDGE...THE WESTERN-MOST BEING A 
NEGATIVELY TILTED MIDDLE TO UPPER TROUGH EXTENDING FROM THE GULF 
OF CALIFORNIA NEAR 28N TO THE SW COAST OF MEXICO NEAR 18N105W. 
MULTI-LAYERED MID TO UPPER LEVEL CLOUDINESS ASSOCIATED WITH 
THIS FEATURE HAVE BEGUN TO CLEAR OUT ACROSS BAJA CALIFORNIA AND 
SHIFT NE INTO NRN MEXICO. TO THE W OF THIS FEATURE...A BROAD 
UPPER LEVEL TROUGH IS CENTERED ACROSS W COASTAL PORTIONS OF N 
AMERICA N OF 26-27N...WHILE A BROAD AND RELATIVELY FLAT UPPER 
LEVEL RIDGE COVERS MUCH OF THE DISCUSSION AREA FROM 12N-26N W OF 
115W. VERY ACTIVE CONVECTION DESCRIBED ABOVE PERSISTS OVER VERY 
WARM WATERS OF THE EPAC E OF 110W...WITH NARROW SYMPATHETIC 
RIDGING BEING MAINTAINED BY DEEP CONVECTIVE TOWERS...WHICH 
SEPARATES UPPER LEVEL WLYS N OF 12N AND E TO NE FLOW ALOFT S OF 
03.5N FLOWING ACROSS THE EQUATOR. 

AT LOWER LEVELS...A 1036 MB HIGH WILL OFFSHORE OF NRN CALIFORNIA 
EXTENDS A RIDGE SE TO NEAR 17N114W. A DRY FRONTAL ZONE WITH 
REINFORCING COOL DRY AIR HAS SUNKEN S ACROSS N PORTIONS OF THE 
AREA DURING THE PAST 12-24 HOURS TO ALONG ABOUT 27N AND W OF 
127W. THE PRES GRADIENT BEHIND THIS BOUNDARY HAS INDUCED A ZONE 
OF 20-25 KT NE TO E WINDS N OF 27N...WHILE FRESH NELY TRADES 
PREVAIL S AND SE OF THIS AREA FROM 28N119W TO 24N125W TO 
17N140W...WHERE SEAS ARE RUNNING 8 TO 9 FT. A STRONG PRES 
GRADIENT ALONG THE CENTRAL AND SRN CALIFORNIA COAST IS GENERATING
NW WINDS TO NEAR GALE FORCE...CREATING NWLY SWELL THAT IS 
PROPAGATING INTO THE NE WATERS...WHERE SEAS WERE REACHING 9 TO 
10 FT ALONG 30N...AND UP TO 13 FT WELL OFFSHORE OF SAN DIEGO.
S OF THE HIGH PRES RIDGE...AND SMALL ZONE OF ELY TRADEWINDS HAVE 
INCREASED TO 20 KT FROM 06N TO 17N W OF 138W AND FROM 06N TO 11N 
BETWEEN 126W AND 138W. THE HIGH WILL WEAKEN SLIGHTLY AND SHIFT 
SW THROUGH EARLY NEXT WEEK...WITH ASSOCIATED FRESH WINDS ALSO 
SHIFTING W AND SW.

TO THE E AND SE OF THIS...LIGHT TO MODERATE MONSOONAL FLOW 
PREVAILS GENERALLY E OF 105W AND CONTINUES TO FORCE ACTIVE 
CONVECTION ACROSS THE AREA. THESE CONDITIONS ARE EXPECTED TO 
PREVAIL THROUGH THE WEEKEND. A NEW PULSE OF VERY LONG PERIOD SRN 
HEMI SWELL WAS CROSSING THE EQUATOR THIS MORNING AND WILL 
DOMINATE SEAS ACROSS THE TROPICS THROUGH THE WEEKEND.  

$$
STRIPLING