000
AXPZ20 KNHC 142132
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU APR 14 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 
2100 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 04N77 
TO A 1009 MB LOW PRES NEAR 05N91W TO 03N110W TO 03N125W TO 
02N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
FROM 02N TO 07N BETWEEN 84W AND 92W. SIMILAR CONVECTION IS 
WITHIN 90 NM S OF AXIS FROM 103W TO 107W AND WITHIN 70 NM N OF 
AXIS BETWEEN 107W AND 112W. A CLUSTER OF MODERATE TO ISOLATED 
STRONG CONVECTION IS FROM 02N TO 04N BETWEEN 117W AND 120W. 
SCATTERED MODERATE CONVECTION IS NOTED NEAR 05N122W AND NEAR 
02N133W.

...DISCUSSION...
A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE N WATERS. AN UPPER 
LEVEL RIDGE COVERS THE NW CORNER. THE UPPER LEVEL TROUGH ENTERS 
THE REGION THROUGH NORTHERN BAJA CALIFORNIA AND EXTENDS SW TO 
NEAR 21N125W. MODERATE TO STRONG UPPER LEVEL SUBSIDENCE AND 
IMPLIED DRY AIR MASS IS NOTED N OF 18N W OF 120W...AND N OF 24N 
E OF 120W...INCLUDING N AND CENTRAL BAJA CALIFORNIA. AN UPPER 
LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE GULF OF 
TEHUANTEPEC. S TO SW FLOW BETWEEN THIS ANTICYCLONE AND THE ABOVE 
MENTIONED TROUGH IS ADVECTING A PLUME OF MID TO UPPER LEVEL 
MOISTURE FROM ITCZ CONVECTION TOWARD THE SOUTHERN TIP OF BAJA 
CALIFORNIA INTO NORTH-CENTRAL MEXICO.

IN THE DEEP TROPICS AN ANTICYCLONIC CIRCULATION IS CENTERED NEAR 
8N125W. A DIFFLUENT PATTERN ALOFT SE OF THIS ANTICYCLONE IS 
HELPING TO INDUCE CONVECTION ALONG THE ITCZ FROM 105W-123W.

A 1033 MB SURFACE HIGH PRES LOCATED NEAR 32N128W EXTENDS A RIDGE 
SE OVER THE FORECAST WATERS TO NEAR 14N106W. A WINDSAT PASS FROM 
THIS MORNING AND THE SUBSEQUENT 1712 UTC ASCAT PASS SHOW A BROAD 
AREA OF FRESH TO STRONG TRADE WINDS OF 20 TO 25 KT ON THE 
SOUTHERN PERIPHERY OF THE RIDGE COVERING ROUGHLY THE REGION FROM 
05N TO 25N W OF 120W. THESE WINDS COMBINED WITH NW SWELL ARE 
ALLOWING SEAS TO BUILD TO 11-12 FT. THE HIGH PRES IS FORECAST TO 
REMAIN NEARLY STATIONARY OVER THE NEXT 24 HOURS. LITTLE CHANGE 
IS EXPECTED IN THE STRENGTH AND AREAL EXTENT OF THESE TRADE 
WINDS THROUGH FRI MORNING THEN WINDS AND SEAS ARE FORECAST TO 
DIMINISH LATE FRI INTO SAT AS HIGH PRES SLIGHTLY WEAKENS. 
PRESSURE GRADIENT BETWEEN THE HIGH AND LOWER PRES OVER MEXICO 
IS RESULTING IN NW TO N WINDS OF 20 TO 25 KT W OF THE BAJA 
CALIFORNIA PENINSULA TO AROUND 125W. FEW SHIP OBSERVATIONS ALONG 
WITH THE 1712 UTC ASCAT PASS CORROBORATED THESE WIND SPEEDS. 
ALSO EXPECT INCREASING WINDS UP TO 25 KT ACROSS THE GULF OF 
CALIFORNIA TONIGHT AS HIGH PRES SETTLES OVER THE GREAT BASIN. 
DESPITE THE SHORT FETCH...NOAA WW3 INDICATES SEAS BUILDING TO 8 
FT IN THE GULF OF CALIFORNIA NEAR 26N110W EARLY FRI MORNING. 

AS PREVIOUSLY MENTIONED...A 1009 MB LOW PRES IS EMBEDDED WITHIN 
THE ITCZ NEAR 05N91W. THE CLOUD FIELD SHOWS SOME CYCLONIC 
TURNING AND TWO CONSECUTIVE ASCAT PASSES INDICATE A BROAD 
CYCLONIC CIRCULATION. DISORGANIZED SHOWERS AND ISOLATED TSTMS 
ARE ASSOCIATED WITH THIS FEATURE. COMPUTER MODELS SHOW THIS 
SYSTEM PERSISTING OVER THIS REGION FOR THE NEXT SEVERAL DAYS.

GAP WINDS...
GULF OF PAPAGAYO...ELY WINDS TO 20 KT ARE STILL PULSING THROUGH 
THE GULF OF PAPAGAYO WITH SEAS REMAINING JUST BELOW 8 FT. THE 
WINDS ARE EXPECTED TO DECREASE TO BELOW 20 KT BY TONIGHT.

GULF OF PANAMA...NLY WINDS TO 20 KT ARE BLOWING THROUGH THE GULF 
OF PANAMA. HOWEVER...THE PRES GRADIENT IS EXPECTED TO RELAX AND 
THE WIND WILL DECREASE TO LESS THAN 20 KT FRI MORNING.

$$
GR