000
AXPZ20 KNHC 150238
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI APR 15 2011

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 04N77 
TO A 1008 MB LOW PRES NEAR 05N91W TO 03N110W TO 03N125W TO 
02N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
FROM 04N TO 07N BETWEEN 88W AND 92W. SCATTERED MODERATE 
CONVECTION IS NOTED FROM 01N TO 03N BETWEEN 87W AND 90W. SIMILAR 
CONVECTION IS WITHIN 60-90 NM EITHER SIDE OF AXIS FROM 104W TO 
125W.  

...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. A CUT-OFF LOW IS BEGINNING TO DEVELOP ALONG THE 
TROUGH AXIS NEAR 25N120W. MODERATE TO STRONG UPPER LEVEL 
SUBSIDENCE AND IMPLIED DRY AIR MASS IS OBSERVED N OF 18N W OF 
120W...AND N OF 24N E OF 120W...INCLUDING N AND CENTRAL BAJA 
CALIFORNIA. AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED 
OVER THE GULF OF TEHUANTEPEC HAS A RIDGE EXTENDING NW TOWARD 
BAJA CALIFORNIA. A PLUME OF MID/UPPER LEVEL MOISTURE LIES 
BETWEEN THIS ANTICYCLONE AND THE ABOVE MENTIONED TROUGH 
EXTENDING FROM NEAR 18N120W TOWARD THE SOUTHERN TIP OF BAJA 
CALIFORNIA INTO NORTH-CENTRAL MEXICO.

IN THE DEEP TROPICS AN ANTICYCLONIC CIRCULATION IS LOCATED NEAR 
8N125W. A DIFFLUENT PATTERN ALOFT SE OF THIS ANTICYCLONE IS 
HELPING TO INDUCE CONVECTION ALONG THE ITCZ FROM 110W-120W.

A 1031 MB SURFACE HIGH PRES SITUATED NEAR 32N128W EXTENDS A 
RIDGE SE OVER THE FORECAST WATERS TO NEAR 17N115W. A COUPLE OF 
ASCAT PASSES FROM 1712 UTC AND 1854 UTC ALONG WITH SOME SHIP 
OBSERVATIONS SHOWED 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 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 AND THE MOST RECENT 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. THE COASTAL CITIES OF LOS MOCHIS AND LORETO IN MEXICO 
WERE REPORTING SUSTAINED WINDS OF 20 TO 25 KT. 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 1008 MB LOW PRES IS EMBEDDED WITHIN 
THE ITCZ NEAR 05N91W. THE CLOUD FIELD SHOWS SOME CYCLONIC 
TURNING AND TWO CONSECUTIVE ASCAT PASSES INDICATED A BROAD 
CYCLONIC CIRCULATION. DISORGANIZED SHOWERS AND TSTMS ARE 
ASSOCIATED WITH THIS FEATURE. COMPUTER MODELS SHOW THIS SYSTEM 
PERSISTING OVER THIS REGION FOR THE NEXT SEVERAL DAYS.

GAP WINDS...
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