000
AXPZ20 KNHC 230924
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN MAY 23 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC.

...TROPICAL WAVES...

TROPICAL WAVE FROM 03N119W TO 11N116W MOVING W 10 KT. THERE IS 
NO SIGNIFICANT CONVECTION ASSOCIATED WITH THIS WAVE.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 11N86W TO 
08N96W TO 09N106W TO 08N120W TO 06N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION LIES WITHIN 300 NM S OF THE ITCZ AXIS 
BETWEEN 84W AND 89W. SCATTERED MODERATE CONVECTION LIES WITHIN 
75 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 97W AND 102W...WITHIN 
90 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 122W AND 127W...AND 
WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS W OF 131W AND 138W.

...DISCUSSION...
THE RIDGE EXTENDING FROM A 1035 MB HIGH PRES CENTER NEAR 35N150W 
TO 13N115W DOMINATES THE SURFACE PATTERN OVER THE FORECAST AREA 
W OF 110W. THERE IS A TIGHT PRES GRADIENT IN PLACE BETWEEN THIS 
RIDGE AND TROUGHING IN THE U.S. GREAT BASIN. NW TO N WINDS 
WITHIN AT LEAST 390 NM OF THE W COAST OF BAJA CALIFORNIA ARE 
IN THE 20-25 KT RANGE ACCORDING TO THE 0532 UTC ASCAT PASS WITH 
SHIP A8MX4 NEAR 24N116W REPORTING 23 KT N WINDS AND 14 FT SEAS 
AT 0600 UTC. THE STRONG PRES GRADIENT OVER NE WATERS WILL BE 
MAINTAINED THE NEXT FEW DAYS WITH THE MAIN PATTERN CHANGE BEING 
A SHIFT E IN THE PRES GRADIENT...ALLOWING THE 20-25 KT WINDS TO 
GRADUALLY CONTRACT E TOWARD THE COAST. THE EASTWARD SHIFTING 
GRADIENT SHOULD ALSO INCREASE THE NW TO N WINDS IN THE GULF OF 
CALIFORNIA TO 20-25 KT BY EARLY MON MORNING. LOOK FOR NE TRADE 
WINDS BETWEEN THE RIDGE AND THE ITCZ...CURRENTLY IN THE 20-25 KT 
RANGE ACCORDING TO THE 0530 UTC ASCAT PASS...TO REMAIN IN PLACE 
GENERALLY W OF 128W FOR THE NEXT TWO DAYS.

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 13N117W WITH A RIDGE 
EXTENDING SE TO 09N108W THEN NE 14N95W AND THEN SE TO TO THE 
EASTERN BORDER OF NICARAGUA AND COSTA RICA. THE DIFFLUENT 
CONDITIONS INDUCED BY THIS RIDGE ALOFT IN ADDITION TO LOW LEVEL 
MOISTURE POOLED NEAR A SURFACE TROUGH FROM 04N91W TO 14N89W IS 
ENHANCING THE CONVECTION OVER EL SALVADOR...SOUTHERN 
HONDURAS...NICARAGUA...AND NORTHERN COSTA RICA INCLUDING 
OFFSHORE WITHIN 60 NM OF COAST. 20-30 KT OF NE SHEAR CAN BE 
FOUND S OF THE RIDGE AXIS E OF 105W. THIS SHEAR IS CURRENTLY 
INHIBITING DEEP CONVECTION S OF 07N. A DEVELOPING MID LEVEL 
CYCLONIC GYRE FROM COSTA RICA/NICARAGUA SW INTO THE PACIFIC IS 
ASSOCIATED WITH THE AFOREMENTIONED SURFACE TROUGH AND IS 
EXPECTED TO ENHANCE MID TO LOW LEVEL SW WINDS TO 20 KT IN THE 
REGION FROM 03N TO 09N BETWEEN 85W AND 100W BY EARLY MON 
MORNING. MEANWHILE...THE 60-80 KT SOUTHERN STREAM UPPER JET LIES 
FROM 13N140W TO 24N130W TO 21N112W AND THEN NE THROUGH MAZATLAN 
MEXICO. THE DIFFLUENT REAR RIGHT QUADRANT OF THIS UPPER JET IS 
SUPPORTING SOME CONVECTION ALONG THE ITCZ W OF 122W. SOME 
CONVECTIVE BLOW OFF FROM THE ITCZ IS BEING TRANSPORTED TO THE NE 
BY THIS JET.

LARGE CROSS-EQUATORIAL LONG PERIOD SW SWELL CONTINUES TO IMPACT 
MUCH OF THE PACIFIC COASTLINE WITHIN THE FORECAST AREA. WAVE 
HEIGHTS ARE IN THE 8-10 FT RANGE WITH 16-18 SECOND PERIODS. THE 
EXCEPTION TO THIS BEING THE W COAST OF BAJA CALIFORNIA WHERE NW 
WIND WAVES HAVE DRIVEN SEAS UP TO 16 FT. THESE SWELLS WILL BEGIN 
TO FADE BY SUNDAY NIGHT...REACHING 6-8 FT IN 12-14 SECOND 
PERIODS BY MON NIGHT. A NEW SURGE OF LONG PERIOD 
CROSS-EQUATORIAL SWELL WILL MOVE INTO S WATERS MON.

$$
SCHAUER