000
AXPZ20 KNHC 142133
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 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 WAS ALONG 05N TO 06N 
BETWEEN 105W AND 140W. SCATTERED MODERATE AND ISOLATED STRONG  
CONVECTION WAS FROM 04N TO 07N BETWEEN 100W AND 110W AND WITHIN 
120 NM N OF THE AXIS BETWEEN 125W AND 129W AND ALSO WITHIN 75 NM 
S OF THE AXIS BETWEEN 132W AND 135W.

...DISCUSSION...

ALOFT...A DEEP LAYERED TROUGH DOMINATES THE FAR NE PACIFIC THIS 
AFTERNOON CENTERED ON AN UPPER CYCLONE NEAR 42N130W EXTENDING 
S-SE TO 22N130W. MID TO UPPER LEVEL MOISTURE WAS ROTATING 
THROUGH THIS TROUGH N OF A LINE FROM 24N140W TO 25N125W TO NEAR 
THE CALIFORNIA AND MEXICO BORDER JUST S OF SAN DIEGO. A LARGE 
BAND OF DRY AIR AND SUBSIDENCE WAS APPARENT ON WATER VAPOR 
IMAGERY WITHIN 120 TO 360 NM S-SE OF THIS SAME LINE...INDICATING 
MID TO UPPER CONVERGENCE WITHIN A 50-75 KT JET SEGMENT.

A SMALL UPPER CYCLONE HAS CUT OFF OVER THE DEEP TROPICAL PACIFIC 
NEAR 03N121W...WITH ITCZ RELATED CONVECTION FLARING WITHIN 180 
NM OVER THE NW QUADRANT. A LARGE UPPER RIDGE DOMINATED THE AREA 
E OF 118W...WITH THE MEAN RIDGE AXIS EXTENDING FROM OVER THE 
SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA SE TO A PARENT 
ANTICYCLONE NEAR 11N93W SW OF THE COASTS OF GUATEMALA AND EL 
SALVADOR.

AT THE SURFACE...ANTICYCLONIC FLOW DOMINATES THE AREA W OF 
105W...CENTERED ON A 1032 MB HIGH WELL NW OF THE AREA NEAR 
36N150W. AN ASSOCIATED SURFACE RIDGE EXTENDS SE FROM THE HIGH TO 
NEAR 15N106W. THE PRESSURE GRADIENT HAS TIGHTENED ENOUGH E OF 
THE RIDGE TO PRODUCE FRESH NWLY WINDS WITHIN 240 NM W OF THE 
BAJA CALIFORNIA PENINSULA. EXPECT THIS SCENARIO TO PREVAIL 
TONIGHT EXPANDING TO ENCOMPASS THE AREA N OF 22N W TO 117W SUN 
NIGHT THROUGH MON AFTERNOON.

E OF 105W...WEAK MONSOONAL FLOW PREVAILS WITH S TO SW WINDS 
10-15 KT PREVAILING S OF A TROUGH EXTENDING FROM NEAR THE PANAMA 
AND COSTA RICA BORDER TO 06N88W TO 10N99W. VERY ACTIVE 
CONVECTION WAS NOTED IN THE CONVERGENT SWLY FLOW S OF THE 
TROUGH. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION WAS 
NOTED FROM 03N TO 06N BETWEEN 83W AND 93W...WITH SCATTERED 
MODERATE AND ISOLATED STRONG CONVECTION FROM 04N TO 08N E OF 83W.
MODERATE NORTHERLY LOW LEVEL FLOW ACROSS CENTRAL AMERICA WILL 
CONTINUE TO PROVOKE VERY ACTIVE CONVECTION ACROSS THIS AREA E OF 
95W DURING THE NEXT 24 HOURS.

THE FIRST DAY OF THE 2011 EASTERN PACIFIC HURRICANE SEASON 
BEGINS TOMORROW...MAY 15.

$$
LEWITSKY