000
AXPZ20 KNHC 201610
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN MAY 20 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 8N78W 
9N90W 6N105W 7N125W 6N140W. NUMEROUS MODERATE CONVECTION IS S OF 
THE AXIS WITHIN 200NM OF THE COLOMBIAN COAST. SCATTERED 
MODERATE/ISOLATED STRONG IS OFF THE CENTRAL AMERICAN COAST N OF 
8N BETWEEN 84W-92W. SIMILAR ACTIVITY IS WITHIN 150NM EITHER SIDE 
OF THE AXIS BETWEEN 93W-108W. SCATTERED MODERATE IS WITHIN 120NM 
EITHER SIDE BETWEEN 110W-115W...AND W OF 140W. 

...DISCUSSION...

A QUASI STATIONARY 1029MB SFC HIGH NEAR 29N138W DOMINATES MUCH 
OF THE DISCUSSION AREA W OF 110W. THIS IS PRODUCING MODERATE TO 
FRESH TRADES ESPECIALLY FROM 10N-25N W OF 125W. THE GRADIENT 
ALSO REMAINS SQUEEZED A BIT E OF THE HIGH AND W OF NORTHERN 
BAJA...AS THE RIDGING INTERACTS WITH INVERTED TROUGHING THROUGH 
THE GULF OF CALIFORNIA. THIS IS PRODUCING AN AREA OF 
~20KT N TO NW WINDS AND 8-12 FT SHORT PERIOD N/NW SWELL IN THE 
AREA N OF 25N BETWEEN 115W AND 128W. BOTH THE TRADES AND N WINDS 
ARE ONLY EXPECTED TO RELAX SLIGHTLY THROUGH EARLY WEEK. OVERCAST 
LOW CLOUDS WITH THE MARINE LAYER ON THE E SIDE OF ARE BANKING UP 
AGAINST THE COAST OF N AND CENTRAL BAJA...BUT SHOULD THIN A BIT 
THROUGH LATE AFTERNOON. 

THIS MORNINGS QUIKSCAT PASS DEPICTED 20-25 KT WINDS IN THE GULF 
OF TEHUANTEPEC WITH A FEW 25-30 KT VECTORS. THE NAM AGAIN 
APPEARS TO HAVE THE BEST HANDLE ON THIS...SO HAVE LEANED TOWARDS 
THAT SOLUTION OVER THE NEXT COUPLE OF DAYS...WHICH RELAXES THE 
WINDS BELOW 20 KT THIS EVENING WITH ANOTHER WEAKER PULSE TO 20 
KT TOMORROW MORNING.   

WEAK UPPER TROUGH IS OVER THE FAR W PORTION OF THE AREA S OF 20N 
ALONG 140W. ANOTHER UPPER TROUGH EXTENDS S FROM SOUTHERN 
CALIFORNIA TO NEAR 23N118W. THIS IS ADVECTING VERY DRY/STABLE 
AIR INTO THE AREA JUST W OF SOUTHERN BAJA. AN UPPER HIGH IS 
CENTERED S OF PUERTO ESCONDIDO MEXICO NEAR 15N99W. WSW FLOW NW 
OF THIS HIGH IS ADVECTING MOISTURE OVER ITCZ CONVECTION THROUGH 
THE EPAC WATERS AND OVER CENTRAL MEXICO. ANOTHER UPPER HIGH IS 
OVER VENEZUELA. UPPER DIFFLUENT ZONE BETWEEN THE TWO UPPER HIGHS 
IS SUPPORTING THE CONVECTION W OF COSTA RICA/NICARAGUA. 

$$
WILLIS