000
AXPZ20 KNHC 122130
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE APR 12 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 05N77W 
TO 1011 MB LOW PRES NEAR 07N89W TO A SECOND LOW PRES NEAR 
08N101W TO 03N120W TO 00N132W. SCATTERED MODERATE CONVECTION IS 
NOTED WITHIN 110 NM S OF AXIS E OF 80W TO THE COAST OF COLOMBIA. 
SIMILAR CONVECTION IS ALSO SEEN WITHIN 90 NM SE QUADRANT OF 
FIRST LOW PRES...AND FROM 05N TO 08N BETWEEN 100W AND 105W.  

...DISCUSSION...
A TROUGH/RIDGE PATTERN DOMINATES MOST OF THE FORECAST AREA. AN 
UPPER-LEVEL TROUGH ENTERS THE REGION NEAR 30N128W THEN CONTINUES 
SW TO 20N140W. A 70-110 KT JETSTREAM BRANCH IS SE OF THE TROUGH 
AXIS FROM 24N131W TO SOUTHERN CALIFORNIA INTO THE SW CONUS. A 
LARGE UPPER-LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER 
CENTRAL MEXICO NEAR 20N101W. S TO SW FLOW BETWEEN THESE TWO 
UPPER LEVEL FEATURES IS ADVECTING MID TO UPPER LEVEL MOISTURE 
FROM ITCZ CONVECTION TOWARD SOUTHERN BAJA CALIFORNIA INTO NW 
MEXICO. WITH THE EXCEPTION OF A FEW SHOWERS DOWNSTREAM OF THE 
THE GULF OF TEHUANTEPEC...MODERATE TO STRONG SUBSIDENCE WITH DRY 
STABLE AIR AT THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE 
COVERS THE AREA N OF 10N E OF 105W. 

A 1028 MB HIGH PRES LOCATED NEAR 34N133W EXTENDS A RIDGE SE OVER 
THE FORECAST WATERS COVERING THE AREA N OF 10N W OF 110W. A 
BROAD AREA OF NE TRADE WINDS IN THE 20 TO 25 KT RANGE IS 
OBSERVED ON THE SOUTHERN PERIPHERY OF THE RIDGE COVERING ROUGHLY 
THE AREA FROM 05N TO 20N W OF 120W. LITTLE CHANGE IS EXPECTED 
OVER THE NEXT COUPLE OF DAYS AS HIGH PRES REMAINS IN CONTROL OF 
THE REGION. WINDS ARE FORECAST TO INCREASE TO 20-25 KT W THE 
BAJA CALIFORNIA PENINSULA AS PRES GRADIENT TIGHTENS BETWEEN HIGH 
PRES AND LOWER PRES OVER NE MEXICO. IN ADDITION...EXPECT 
INCREASING WINDS ACROSS THE GULF OF CALIFORNIA N OF 26N IN ABOUT 
48 HOURS. 

GAP WINDS...
GULF OF PAPAGAYO...FRESH NE TO E WINDS WILL CONTINUE TO PULSE TO 
20 KT THROUGH THE GULF OF PAPAGAYO THE NEXT COUPLE OF DAYS WITH 
SEAS REMAINING JUST BELOW 8 FT. THE LARGEST AREAL EXTENT OF THE 
20 KT WINDS WILL BE IN THE EARLY MORNING HOURS WITH THE AID OF 
NOCTURNAL DRAINAGE FLOW.
 
GULF OF TEHUANTEPEC...A WEAK COLD FRONT IN THE GULF OF MEXICO 
CURRENTLY MOVING THROUGH THE ISTHMUS OF TEHUANTEPEC IS PRODUCING 
NLY WINDS OF 20 KT ACROSS THE GULF OF TEHUANTEPEC. THE MOST 
RECENT ASCAT PASS AND LATEST SURFACE OBSERVATIONS FROM IXTEPEC 
MEXICO VERIFIED THESE WIND SPEEDS. THIS WILL BE A BRIEF EVENT  
ENDING WED AFTERNOON.

$$
GR