000
AXPZ20 KNHC 240330
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN APR 24 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 
0330 UTC.

...ITCZ...
AXIS ALONG AXIS FROM 10N85W TO 08N90W TO 08N99W TO 04N110W TO 
02N140W.  SCATTERED MODERATE TO STRONG CONVECTION WITHIN 60 NM S 
OF AND 270 NM N OF AXIS FROM 105W TO 111W.  ISOLATED MODERATE TO 
STRONG CONVECTION WITHIN 90 NM OF AXIS W OF 115W.

...DISCUSSION...
UPPER LEVEL LONGWAVE TROUGH CROSSES EPAC FROM 32N120W TO 18N140W 
WITH VERY DRY AIR MASS WITH 180 NM OF AXIS.  ALTHOUGH PLENTY OF 
MOISTURE ALOFT AVAILABLE NW OF TROUGH AXIS...LARGE SURFACE RIDGE 
RESTRICT ANY SIGNIFICANT UPLIFTING OR CONVECTION.  ANTICYCLONE 
GYRE AT 12N106W ANCHORS UPPER LEVEL RIDGE WITH FLATTENED CREST 
ALONG 106W EFFECTIVELY BLOCKING TROUGH FROM FURTHER SOUTHWARD 
ENCROACHMENT.  ABUNDANT MOISTURE RUNS SW-NE E OF 110W PARALLEL 
TO TROUGH AXIS RIDING WEAKENING 70 KT JET CORE HEADING TOWARDS 
CENTRAL BAJA CALIFORNIA AND MEXICO.  MOISTURE REACHING AS FAR E 
AS CENTRAL TEXAS WHERE COLD FRONT IS EXPECTED TO CONVERT IT TO 
MUCH NEEDED RAIN. 

RIDGE ALOFT MAINTAINS VERY DRY AREA BETWEEN ITCZ CONVECTION AND  
MOIST JET STREAM.

AT THE SURFACE...
WEAK TROUGH ALONG 100W FROM 02N-10N CONTINUES DRIFTING W WITH 
SCATTERED CONVECTION WITHIN 150 NM E OF AXIS N OF 06N.  
DIFFLUENT FLOW ALOFT AHEAD OF PATH MAY ENHANCE CONVECTION AS 
TROUGH APPROACHES 107W...BUT MODEL GUIDANCE DOES NOT ASSOCIATE 
ANY ROTATION NOR TROPICAL ORGANIZATION TO IT.  

HIGH PRES CENTER 1023 MB OVER FAR NW PART OF AREA AT 28N145W HAS 
RIDGE EXTENDING E TO 15N106W.  PRES GRADIENT BETWEEN RIDGE AND 
WEAK TROUGH ALONG MEXICO SIERRA MADRE SUPPORTS FRESH NW BREEZE  
N OF 23N E OF 118W TO W COAST OF BAJA CALIFORNIA.  PRES GRADIENT 
BETWEEN RIDGE AND LOWER PRES IN VICINITY OF ITCZ SUPPORT 
MODERATE TO FRESH TRADES FROM 08N TO 18N W 0F 135W.  HIGH PRES 
CENTER SHIFT NW OF AREA IN NEXT 24 HOURS...BUT RIDGE HOLDS TO 
ITS POSITION THROUGH FORECAST PERIOD.  

$$
WALLY BARNES