000
AXPZ20 KNHC 181532
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 18 2006

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 
1515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 5N77W 6N83W 12N89W 7N118W 6N140W. 
SCATTERED MODERATE CONVECTION N OF 5N BETWEEN 83W-92W. SCATTERED 
MODERATE WITHIN 240 NM S OF THE AXIS BETWEEN 99W-113W...AND WITHIN 
150 NM N OF THE AXIS BETWEEN 113W-123W. WIDELY SCATTERED SHOWERS/ 
TSTMS WITHIN 120 NM OF THE AXIS BETWEEN 126W-139W.

...DISCUSSION...

W OF 110W...
DEEP-LAYERED LOW JUST N OF THE AREA NEAR 32N138W IS BEGINNING TO 
LIFT SLIGHTLY NE BUT THE MAIN TROUGH STILL EXTENDS S TO 20N AND E TO 
ABOUT 125W. UPPER LEVEL CONFLUENCE INTO THE BASE OF THE TROUGH IS 
CREATING AN AREA OF MODERATE SUBSIDENCE JUST E OF THE HAWAIIAN 
ISLANDS THAT PROTRUDES INTO THE AREA FROM 18N-26N W OF 135W. A 
WEAKENING COLD FRONT IS ASSOCIATED WITH THE TROUGH AND EXTENDS FROM 
30N134W TO 24N140W...WITH MOST OF THE SHOWER/TSTM ACTIVITY N OF THE 
AREA. AN UPPER RIDGE IS ALIGNED ALONG 125W AND IS LOCATED JUST 
UPSTREAM OF A SHEARED UPPER LOW OVER CNTRL BAJA CALIFORNIA. AN AREA 
OF STRONG SUBSIDENCE EXTENDS UP TO 400 NM S AND W OF THE LOW AND IS 
PRODUCING A STRONG INVERSION WITH THE MARINE LAYER N OF 21N E OF 
121W TO THE BAJA COAST. FARTHER S...AN UPPER RIDGE AXIS EXTENDS FROM 
12N110W TO 10N140W WITH THE ITCZ MOISTURE AXIS LYING UP TO 350 NM TO 
THE S.

E OF 110W...
WITH BROAD MID/UPPER TROUGHING OVER WRN MEXICO...A DEEP TROPICAL 
MOISTURE PLUME EXTENDS FROM NEAR THE ITCZ BETWEEN 100W-110W NEWD 
ACROSS SE MEXICO AND MOST OF CNTRL AMERICA. A WEAK INVERTED UPPER 
TROUGH EXTENDS FROM EQ107W TO 7N100W AND IS SURROUNDED BY 
MODERATE/STRONG SUBSIDENCE. CLUSTERS OF TSTMS HAVE BEEN PULSING 
ABOUT 350 NM SW OF THE CNTRL AMERICA COASTLINE PRIMARILY DUE TO 
CONVERGENCE OF LOW-LEVEL SLY FLOW...AND ENHANCED BY BROAD RIDGING 
ALOFT STRUNG NE/SW ACROSS THE AREA. SOME OF THESE TSTMS ARE 
CURRENTLY HUGGING THE COASTS OF EL SALVADOR AND NICARAGUA...AND 
ANOTHER LARGE CLUSTER IS MOVING FROM THE EXTREME SW CARIBBEAN SW 
ACROSS COSTA RICA/WRN PANAMA. GAP WINDS OVER THE TEHUANTEPEC REGION 
HAVE CREATED A CLEAR SLOT IN THE CLOUDINESS N OF 12N BETWEEN 
93W-98W...AND ARE ALSO CREATING SEVERAL CYCLONIC/ANTICYCLONIC 
SURFACE CIRCULATIONS AS THEY INTERACT WITH THE ITCZ.

$$
BERG