000
AXPZ20 KNHC 161527
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAY 16 2012

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ALETTA IS CENTERED NEAR 11.8N 112.6W AT 16/1500 
UTC MOVING W OR 280 DEG AT 8 KT. THIS MOTION IS EXPECTED TO 
CONTINUE DURING THE NEXT DAY OR SO. ESTIMATED MINIMUM CENTRAL 
PRES 1004 MB. MAXIMUM SUSTAINED WINDS 35 KT GUSTS TO 45 KT.  
PLEASE REFER TO THE LATEST PUBLIC ADVISORY TCPEP1/WTPZ31 KNHC 
FOR MORE DETAILS. SCATTERED MODERATE TO STRONG CONVECTION IS 
NOTED WITHIN 90 NM W SEMICIRCLE AND 120 NM NE QUADRANT OF 
CENTER. A GRADUAL WEAKENING IS FORECAST DURING THE NEXT 48 HOURS 
AS VERTICAL SHEAR INCREASES AND DRY AIR APPROACHES. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 6N78W TO LOW PRES NEAR 9N97W 1008 MB TO 
12N106W. ITCZ FROM 6N116W TO 3N140W. CLUSTER OF MODERATE TO 
STRONG CONVECTION FROM 10N-14N BETWEEN 95W-101W. NUMEROUS 
MODERATE STRONG CONVECTION FROM 7N-11N BETWEEN 106W-111W.

...DISCUSSION...
MID/UPPER LEVEL RIDGE WITH AXIS ROUGHLY ALONG 128W CONTINUES TO 
DOMINATE THE NW PORTION OF THE DISCUSSION AREA WHILE A DEEP 
LAYER TROUGH PERSISTS BETWEEN 140W AND THE HAWAIIAN ISLANDS. S 
AND SW WINDS BETWEEN THE TROUGH AND THE RIDGE ARE TRANSPORTING 
MID/UPPER LEVEL MOISTURE ACROSS THE NW CORNER OF THE AREA. 
STRONG SUBSIDENCE WITH DRY/STABLE AIR MASS AT THE MIDDLE AND 
UPPER LEVELS COVERS THE AREA N OF 20N E OF 120W INCLUDING THE 
BAJA CALIFORNIA PENINSULA AND NW MEXICO. AN ANTICYCLONIC 
CIRCULATION REMAINS CENTERED OVER CENTRAL AMERICA WITH A RIDGE 
DOMINATING THE WATERS E OF 110W. THIS FEATURE IS PROVIDING A 
FAVORABLE ENVIRONMENT FOR ACTIVE TSTMS E OF 110W.

SURFACE RIDGE EXTENDS SE FROM HIGH PRES N OF THE AREA WITH RIDGE 
N OF 15N W OF 115W. LOWER PRES OVER NORTHERN MEXICO COMBINED 
WITH THE RIDGE PROVIDING A TIGHT ENOUGH PRES GRADIENT THAT IS 
PRODUCING AN AREA OF 20 KT NW WINDS NEAR THE COAST OF BAJA 
CALIFORNIA N OF 27N E OF 119W. THE HIGH IS EXPECTED TO REMAIN 
NEARLY STATIONARY AND WEAKEN DURING THE NEXT 24 HOURS. AS A 
RESULT...EXPECT WINDS TO DIMINISH BELOW 20 KT.

A 1008 MB LOW PRES IS CENTERED NEAR 9N97W. SCATTERED MODERATE TO 
STRONG TSTMS ARE WITHIN 240 NM N SEMICIRCLE OF THE LOW.

HIGH PRES BUILDING SOUTHWARD ALONG THE GULF COAST OF MEXICO WILL 
INDUCE 20-25 KT N-NE WINDS INTO THE GULF OF TEHUANTEPEC TODAY 
THROUGH EARLY FRI.

$$
DGS