000
AXPZ20 KNHC 162202
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 16 2010

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

BASED ON 1500 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS FROM 02N78W TO 08N85W TO 
05N91W TO 10N105W TO 07N110W TO 11N135W TO 10N140W. NO 
SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

N OF 24N...A VIGOROUS MID TO UPPER LEVEL SHORT WAVE TROUGH IS 
EXITING EASTWARD OVER THE BAJA PENINSULA. AN UPPER RIDGE NE OF 
HAWAII NEAR 25N145W IS SHIFTING E TOWARD 22N127W BEHIND THE 
TROUGH...ALLOWING STEERING WINDS TO BECOME MORE ZONAL N OF 23N. 
AS RESULT...A 1007 MB SURFACE LOW CENTERED NEAR 34N130W IS 
MOVING GENERALLY EASTWARD IN ZONAL FLOW ALOFT...WITH A TRAILING 
COLD FRONT THROUGH 26N140W GLIDING SLOWLY EASTWARD OVER THE NEXT 
COUPLE OF DAYS N OF 26N. ASCAT DATA SHOW NW WINDS TO 20 KT 
BEHIND THE FRONT N OF 29N AND E OF 133W. A SHIP WAS REPORTING SW 
WINDS TO 20 KT JUST AHEAD OF THE FRONT N OF 28N. WEAK 1017 MB 
SURFACE HIGH PRES CENTERED NEAR 26N123W WILL SHIFT SE AHEAD OF 
THE FRONT THEN BECOME STATIONARY NEAR 24N125W. 

S OF 24N...THE TRADE WIND FLOW S OF 18N REMAINS ATYPICALLY 
LIGHT...DUE TO FAIRLY WEAK 1017 MB HIGH PRES NEAR 25N121W. 
FURTHER SOUTH...THREE DISTINCT CIRCULATIONS ARE NOTED ALONG THE 
ITCZ IN VISIBLE SATELLITE IMAGERY. ONE IS NOTED NEAR 07N90W AND 
IS GENERALLY STATIONARY WITH AN ESTIMATED PRES OF 1010 MB. A 15Z 
ASCAT PASS SHOWED LIGHT TO MODERATE FLOW ON THE SE SIDE OF THIS 
LOW. THE GFS SHOWS THIS LOW DEEPENING SLIGHTLY BY EARLY 
SUN...WITH NEAR GALE FORCE WINDS ON THE SE SIDE OF THE LOW. THIS 
MAY BE A LITTLE CONVECTIVE FEEDBACK...AND GIVEN THAT THE ECMWF 
IS WEAKER WITH THIS SYSTEM...WINDS WILL LIKELY BE IN THE 20 TO 
25 KT RANGE AS THE LOW DEVELOPS. FURTHER WEST...TROUGHS ARE 
NOTED ALONG THE ITCZ NEAR 107W AND 129W...ALTHOUGH GIVEN THE 
WEAK PRES GRADIENT...WINDS WILL REMAIN MODEST NEAR THESE 
FEATURES. FINALLY...FRESH GAP WIND FLOW THROUGH THE GULF OF 
PANAMA WILL PERSIST THROUGH FRI.

$$

CHRISTENSEN