000
AXPZ20 KNHC 200323
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAY 20 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 
0215 UTC.
 
...ITCZ...
AXIS ALONG 10N84W TO 12N92W TO 07N104W TO 05N126W TO 05N140W. 
SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION 
NOTED WITHIN 120 NM N AND 210 NM S OF AXIS BETWEEN 97W AND 107W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 120 
NM OF AXIS FROM 107W TO 135W.

...DISCUSSION...
DEEP LAYERED CYCLONE OVER THE WRN U.S. WITH BROAD TROUGH AXIS 
EXTENDING S INTO N PORTIONS OF DISCUSSION AREA NEAR 28N113W. 
ACROSS THE NW CORNER OF THE AREA...A WELL DEFINED CYCLONIC 
VORTEX WAS EVIDENT AT 26N136W...WITH BROAD ATTENDANT TROUGH 
EXTENDING S TO 04N139W. BROAD ANTICYCLONIC GYRE DOWNSTREAM 
EFFECTIVELY COVERS REMAINDER OF BASIN WITH E-W RIDGE ALONG 
08-12N E OF 130W TO 80W. TROUGHING ALONG 140W COMBINING WITH W 
PORTION OF RIDGE TO ADVECT ABUNDANT TROPICAL MOISTURE FROM ITCZ 
N AND NE. HADLEY CELL WELL ESTABLISHED ACROSS THE TROPICAL EPAC 
AS PERSISTENT RISING MOTION PREVAILS UNDERNEATH UPPER RIDGE...AS 
INDICATED BY PERSISTENT DEEP CONVECTION...WHILE SINKING MOTION 
AND SUBSIDENCE CONTINUE 15-20 DEGREES TO THE N AND S IN BOTH 
HEMISPHERES. 

AT LOW LEVELS...WEAK COLD FRONTAL BOUNDARY HAS DISSIPATED AS IT 
MOVED ACROSS NRN BAJA CALIFORNIA LAST NIGHT...BUT WAS DEPICTED 
IN A 1648 UTC ASCAT PASS ACROSS CENTRAL BAJA AND GULF OF 
CALIFORNIA...INDUCING 20 KT NW FLOW BETWEEN THE PAIR OF ISLANDS 
IN THE NORTHERN GULF AND 26N. OTHERWISE...A HIGH PRES RIDGE 
DOMINATES THE NW TWO-THIRDS OF THE AREA...CENTERED ON A 1025 MB 
HIGH NEAR 35N131W EXTENDING SE TO NEAR 17N110W. MODERATE TO 
FRESH NW BREEZE CONTINUES WITHIN 180 NM OF BAJA CALIFORNIA W 
COAST AND WILL DIMINISH NEXT 48 HOURS AS RIDGE BREAK DOWN 
THROUGH SAT. SUBSIDING CROSS-EQUATORIAL S TO SW SWELLS WILL 
CONTINUE TO MOVE THROUGH MOST OF EPAC BASIN THROUGH FRI EVENING 
BEFORE BEING REINFORCED BY ANOTHER PULSE OF MODERATE SW SWELL 
SAT AND SUN. 

E OF 110W...MONSOONAL LLVL FLOW PREVAILS...WITH S TO SW FLOW S 
OF THE ITCZ E OF 125W DEPICTED BY AFTERNOON SCATTEROMETER 
PASSES. STRONGEST WINDS SUGGESTED AT 15 TO NEAR 20 KT FROM 02N 
TO ITCZ BETWEEN 95W AND 120W...SERVING AS ENHANCED INFLOW INTO 
DEEP CONVECTION PULSING THERE. GLOBAL MODELS SUGGESTING CHANCE 
FOR CONTINUED DEEP CONVECTION ALONG ITCZ BETWEEN 103W AND 112W 
NEXT FEW DAYS...WITH GFS DEVELOPING A SIGNIFICANT SURFACE LOW IN 
THIS AREA...BUT REMAINS THE OUTLIER AT THIS TIME.

$$
STRIPLING