000
AXPZ20 KNHC 141541
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 14 2011

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

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

...ITCZ...

THE ITCZ AXIS IS FLUCTUATING FROM 05N TO 06N BETWEEN 100W AND 
140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
WITHIN 150 NM N OF AXIS. E OF 100W...SCATTERED TO LOCALLY 
NUMEROUS MODERATE TO STRONG CONVECTION WAS NOTED FROM 03N TO 08N 
E OF 88W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS 
NOTED FROM 03N TO 09N BETWEEN 88W AND 100W.

...DISCUSSION...
A DEEP LAYERED TROUGH DOMINATES THE FAR NE PACIFIC THIS 
MORNING...CENTERED ON AN UPPER CYCLONE NEAR 44N135W EXTENDING 
S-SE TO 21N130W. UPPER MOISTURE IS ROTATING THROUGH THE TROUGH N 
OF A LINE FROM 26N140W TO 25N130W TO SOUTHERN CALIFORNIA AND NW 
ARIZONA. A LARGE BAND OF DRY AIR AND SUBSIDENCE IS OBSERVED 
WITHIN 180 TO 400 NM S AND SE OF THIS LINE...INDICATING MID TO 
UPPER CONVERGENCE WITHIN A 50-70 KT JET SEGMENT.

A SMALL UPPER CYCLONE HAS CUT OFF OVER THE DEEP TROPICAL PACIFIC 
NEAR 05N123W...WITH ITCZ RELATED CONVECTION FLARING WITHIN 150 
NM OVER ITS NW QUADRANT. A LARGE UPPER RIDGE DOMINATED THE AREA 
E OF 120W...WITH MEAN AXIS ACROSS MEXICO ALONG 104W. PARENT 
ANTICYCLONE WAS CENTERED NEAR 12N97W. 

AT THE LOW LEVELS...ANTICYCLONIC FLOW DOMINATED THE AREA W OF 
105W...CENTERED ON A 1032 MB HIGH WELL NW OF THE AREA NEAR 
39N150W...WHILE A SMALL COLLAPSING ANTICYCLONE WAS NOTED IN AN 
OVERNIGHT ASCAT PASS NEAR 31N128W. THE ASSOCIATED SURFACE RIDGE 
EXTENDED SE TO NEAR 18N11W. THE PRESSURE GRADIENT HAS TIGHTENED 
E OF THE RIDGE...PRODUCING FRESH NWLY WINDS WITHIN 300 NM W OF 
THE BAJA CALIFORNIA PENINSULA. EXPECT THIS SCENARIO TO PREVAIL 
THROUGH SUNDAY BEFORE EXPAND N ALONG THE BAJA W COAST TO 30N 
SUN NIGHT THROUGH MON.

E OF 105W...WEAK MONSOONAL FLOW PREVAILS...WITH S TO SW WINDS 10 
TO 15 KT PREVAILING S OF A MONSOON TROUGH THAT EXTENDS FROM NEAR 
10N105W TO 06N90W THEN E-NE ACROSS COSTA RICA AND INTO THE FAR 
SW CARIBBEAN. VERY ACTIVE CONVECTION WAS NOTED IN THE CONVERGENT 
SWLY FLOW E OF 88W...AS DESCRIBED ABOVE. MILD 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.

$$
STRIPLING