000
AXPZ20 KNHC 052155
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT FEB 05 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...
THE ITCZ AXIS EXTENDS NW FROM 04N78W TO 08N110W THEN BROADENS AS 
IT TURNS SW TO 44N140W. SCATTERED MODERATE CONVECTION WITH 
OCCASIONAL STRONG FLAREUPS IS OBSERVED WITHIN 120 NM EITHER 
SIDE OF A LINE FROM 04N92W TO 10N106W. LIGHTNING DATA SUGGESTS 
TSTMS WITHIN 120 NM OF 09.5N105W. SMALL CLUSTERS OF MODERATE 
CONVECTION ARE OCCASIONALLY FLARING IN THE VICINITY OF 05N114W 
AND ALONG 05.5N BETWEEN 112W AND 131W.

...DISCUSSION...
A LONG WAVE TROUGH DOMINATES CENTRAL N AMERICA WITH THE BASE OF 
THE TROUGH OVER OLD MEXICO AT 25N107W. A CYCLONIC SHEAR AXIS 
EXTENDS W ACROSS THE DISCUSSION AREA FROM 24N109W TO 26N130W 
THEN INTO A SMALL UPPER CYCLONE QUASI STATIONARY NEAR 26N141W. 
UPPER MOISTURE IS NOTED WITHIN ABOUT 150 NM E OF THE UPPER 
CYCLONE CENTER...BUT THE AREA IS VOID OF DEEP CONVECTION. A 
PRONOUNCED BAND OF VERY DRY UPPER AIR IS INDICATED WITHIN 270 NM 
EITHER SIDE OF A LINE FROM 30N94W TO 25N107W TO BEYOND 32N132W. 
UPPER MOISTURE IS NOTED N OF THIS BAND OF DRY AIR...IS JUST NOW 
ARRIVING ALONG 32N FROM W TEXAS TO THE NORTHERN BAJA CALIFORNIA 
PENINSULA. 

A STATIONARY UPPER CUT OFF CYCLONE W OF THE AREA NEAR 13N146W IS 
BEGINNING TO FILL...BUT IS STILL ENHANCING CLUSTERS OF MODERATE 
CONVECTION FROM 09N TO 14N BETWEEN 139W AND 144W. A LARGE AREA 
OF UPPER DEBRIS MOISTURE IS OBSERVED FROM 07N TO 20N E OF 146W 
AND MERGES WITH ADDITIONAL MOISTURE UNDER AND UPPER RIDGE 
DESCRIBED NEXT. 

AN UPPER LEVEL ANTICYCLONE IS OVER THE DEEP TROPICS NEAR 11N98W 
WITH A RIDGE EXTENDING NW TO A CREST AT 20N140W. UPPER 
DIFFLUENCE ALONG THIS RIDGE IS ENHANCING CONVECTION ALONG THE 
ITCZ BETWEEN 100W AND 112W. THE DEBRIS MOISTURE FANS OVER THE 
TROPICS FROM 03N TO 14N BETWEEN 98W AND 116W. DENSE UPPER 
MOISTURE IS OBSERVED ELSEWHERE UNDER THE UPPER RIDGE...AND 
CONCENTRATES INTO A TROPICAL PLUME WITHIN ABOUT 180 NM EITHER 
SIDE OF A LINE FROM 18N132W TO 16N110W...WHERE THE PLUME NARROWS 
AS IT CONTINUES E ACROSS CENTRAL OLD MEXICO ALONG 20N.

AN UPPER CYCLONE IS PROGRESSING WESTWARD OVER THE W CENTRAL 
CARIBBEAN WITH ITS ENVELOPE OF CYCLONIC FLOW DIPPING S OVER THE 
PACIFIC ALONG THE COAST OF CENTRAL AMERICA NEAR 10N85W. 
OTHERWISE A BROAD UPPER RIDGE EXTENDS WNW FROM COLOMBIA AND IS 
MERGING THE THE ANTICYCLONIC FLOW ASSOCIATED WITH THE 
ANTICYCLONE NEAR 11N98W. THE RESULT IS DRY UPPER AIR AND 
SUBSIDENCE SUPPRESSING CONVECTION TO ONLY ALONG THE ITCZ BETWEEN 
90W AND 100W AS PREVIOUSLY DESCRIBED.

AT THE SURFACE...
A RIDGE EXTENDS FROM 32N135W TO NEAR 15N110W. NE TRADES AT 20 TO 
25 KT CONTINUE SW OF THE RIDGE TO 09N W OF 116W. NW SWELLS ARE  
MIXING WITH TRADE GENERATED NE SWELL OVER THE AREA W OF 105W. 
THE AREA OF NE TO E WINDS AT 20 KT WILL SHIFT TO THE WATERS W OF 
128W BY LATE MON.

GAP WINDS...
GULF OF TEHUANTEPEC...GALE FORCE WINDS HAVE DIMINISHED TO 20 TO 
30 KT IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC. EXPECT WINDS 
TO GRADUALLY DIMINISHING BELOW 20 KT BY EARLY SUN.

GULF OF PAPAGAYO...NE TO E WINDS WILL PULSE AT 20 TO 25 KT 
TONIGHT...THEN PULSE AT 15 TO 20 KT THROUGH MON. 

GULF OF PANAMA...N WINDS AT 15 TO 20 KT WILL CONTINUE THROUGH 
SUN THEN DIMINISH SUN NIGHT.

$$
NELSON