000
AXPZ20 KNHC 201545 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 20 2009

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 
1500 UTC.

...ITCZ...
THE ITCZ AXIS EXTENDS FROM 06N78W 08N90W TO 06N105W TO 09N140W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WITHIN 150 NM S 
OF AXIS E OF 82W...AND WITHIN 90 NM N OF AXIS W OF 120W. 

...DISCUSSION...

W OF 115W...A DEEP LAYER TROUGH EXTENDING FROM OFF THE 
WASHINGTON COAST TO 27N140W IS DIGGING ON THE EAST SIDE OF REX 
BLOCK CENTERED N OF HAWAII. AN ASSOCIATED COLD FRONT EXTENDS 
FROM NORTHERN CALIFORNIA TO 29N140W AND IS SHIFTING ESE. A 1020 
MB SURFACE HIGH PRES NEAR 27N132W IS DISSIPATING AHEAD OF THE 
FRONT. SCATTEROMETER DATA SHOW MODERATE TO FRESH KT TRADE WINDS 
S OF THE HIGH PRES FROM GENERALLY 10N TO 18N W OF 120W. THE 
TRADE WIND FLOW HAS DIMINISHED SLIGHTLY FROM YESTERDAY AS THE 
HIGH TO THE NORTH HAS WEAKENED. TRADES WILL INCREASE LATER TODAY 
HOWEVER AS HIGH PRES BUILDS BEHIND THE FRONT N OF THE AREA. THE 
FRONT ITSELF WILL LIKELY BECOME DIFFUSE THROUGH SAT AS UPPER 
DYNAMICS LIFT OUT. MEANWHILE DIVERGENT FLOW ALOFT ON THE RIGHT 
REAR ENTRANCE AREA OF A WEAK JET MAX ON THE SE SIDE OF THE UPPER 
TROUGH IS INTERACTING WITH THE MODEST TRADE WIND CONVERGENCE TO 
ENHANCE SCATTERED CONVECTION N OF THE ITCZ W OF 120W. LOOKING 
AHEAD THE WEEKEND...THE BLOCKING RIDGE N OF HAWAII WILL BREAK 
DOWN AHEAD OF AN APPROACHING CENTRAL PACIFIC TROUGH. THIS WILL 
ALLOW THE SURFACE RIDGE THAT WILL BUILD BEHIND THE WEAKENING 
COLD FRONT TO REMAIN IN PLACE N OF THE AREA...MAINTAINING A 
BROAD SWATH OF FRESH TO STRONG TRADES FROM 10N TO 25N W OF 120W. 
SE CROSS-EQUATORIAL FLOW WILL CONVERGE WITH THE NE TRADES TO 
KEEP CLUSTERS OF CONVECTION ACTIVE ALONG THE ITCZ W OF 120W AS 
WELL. MEANWHILE ANOTHER SET OF NW SWELL UP TO 10 FT WITH UP TO 
14S PERIODS WILL S INTO THE AREA.

E OF 115W...MAIN ISSUE IS PERSISTENT GAP WINDS. HIGH RESOLUTION 
SCATTEROMETER DATA SHOW WINDS OF 20 TO 30 KT THROUGH THE GULF OF 
PAPAGAYO...AGAIN THIS MORNING DUE TO MAINLY DRAINAGE 
EFFECTS...WITH 20 KT WINDS NOTED OFF OF THE GULF OF FONSECA. 
FRESH TRADE WINDS ARE PUSHING FROM THE SW CARIBBEAN ACROSS 
PANAMA AS WELL...INTO THE GULF OF PANAMA...ENHANCING MODERATE TO 
STRONG NOCTURNAL CONVECTION OFF THE COLOMBIAN COAST.

$$
CHRISTENSEN