East Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 241602
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE NOV 24 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...
AXIS ANALYZED FROM 07N78W TO 05N95W TO 07N1008W TO 08N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM OF 
AXIS W OF 88W. SCATTERED MODERATE CONVECTION WITHIN 60 NM OF 
AXIS BETWEEN 105W AND 110W.  

...DISCUSSION...
ASCAT AND WINDSAT PASSES SINCE LAST EVENING CONTINUE TO SHOW A 
SWATH OF FRESH TO STRONG TRADE WINDS OVER THE DISCUSSION AREA 
FROM 10N TO 25N W OF 120W. THESE WINDS ARE SOUTH OF A 1027 MB 
SURFACE HIGH PRES CENTERED NEAR 35N130W...THAT WILL WEAKEN OVER 
THE NEXT 48 TO 72 HOURS AHEAD OF DEEP LAYER TROUGH DIGGING 
EASTWARD TO THE NORTH OF HAWAII. THE TRADES WILL DIMINISH 
SLIGHTLY IN INTENSITY AND COVERAGE AS THE HIGH PRES TO THE N 
WEAKENS. TRADES WILL INCREASE AGAIN BY THE END OF THE WEEK AS 
HIGH PRES BUILDS BEHIND A COLD FRONT THAT WILL STALL ALONG 30N 
THU INTO FRI.

MEANWHILE A A SHORT WAVE MID TO UPPER TROUGH EXTENDS FROM 
35N130W TO 18N140W...AND WILL SHIFT EASTWARD AND CUTOFF JUST OFF 
THE BAJA COAST NEAR 26N115W BY EARLY THU...TO THE SOUTH OF AN 
UPPER RIDGE OVER THE ROCKIES. WHILE THIS WILL HAVE LITTLE IMPACT 
ON WEATHER IN THE IMMEDIATE VICINITY...IT WILL SERVE TO MAKE THE 
OVERALL PATTERN MORE AMPLIFIED...AND ALLOW A LONG WAVE TROUGH TO 
DIG ACROSS THE EASTERN U.S. LATER IN THE WEEK...AND PUSH A COLD 
FRONT THROUGH THE GULF OF MEXICO. THIS IN TURN WILL ENHANCE GAP 
WIND FLOW THROUGH THE GULF OF TEHUANTEPEC...WHERE STRONG 
NORTHERLY FLOW CAN BE EXPECTED BY WED...REACHING GALE FORCE 
WINDS BY WED NIGHT. 

ASCAT WAS ALSO SHOWING FRESH NORTHERLY WINDS IN THE NORTHERN 
GULF OF CALIFORNIA OVERNIGHT. GIVEN THE STRENGTH OF THE 1036 MB 
SURFACE RIDGE OVER THE GREAT BASIN...IT IS PLAUSIBLE THAT WINDS 
ARE HIGHER IN THE FAR NORTHERN GULF THAN THE ASCAT SCATTEROMETER 
IS SAMPLING.

STRONG NOCTURNAL CONVECTION IS JUST STARTING TO SUBSIDE OFF THE 
COASTS OF PANAMA AND COSTA RICA. THESE THUNDERSTORMS FLARE AS 
THE RESULT OF OVERNIGHT LAND BREEZE CONVERGENCE BEING ENHANCED 
BY DIVERGENT FLOW ALOFT RELATED TO AN UPPER ANTICYCLONE PARKED 
JUST SOUTH OF WESTERN PANAMA. 

A JASON ALTIMETER PASS FROM 08Z INDICATED SEAS OF 8 TO 10 FT IN 
THE AREA OF FRESH AND STRONG TRADES...ALTHOUGH SOME OF THIS IS 
RELATED TO PERSISTENT NW SWELL. A NEW ROUND OF LONG PERIOD NW 
SWELL WITH HEIGHTS TO 15 FT IS EXPECTED TO PASS SE OF 30N140W BY 
LATE WED IN FAR NW SECTIONS OF THE DISCUSSION AREA.

$$

CHRISTENSEN