000
AXPZ20 KNHC 290912
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAR 29 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0715 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 08N78W 
TO 03N93W TO 05N100W TO 02N130W TO 03N140W. SCATTERED MODERATE 
CONVECTION WAS WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS E OF 
93W.

...DISCUSSION...

A 1030 MB HIGH PRES SYSTEM NEAR 33N139W EXTENDS A RIDGE INTO THE 
FORECAST AREA NEAR 32N127W TO 13N103W. FRESH NE TRADE WINDS LIE 
S OF THE RIDGE AXIS FROM 04N TO 25N W OF 124W ACCORDING TO THE 
0516 UTC AND 0656 UTC ASCAT PASSES ALONG WITH SHIP V7FS3 NEAR 
24N140W AT 0700 UTC AND SHIP NEAR 25N136W AT 0600 UTC. THESE 
TRADES HAVE RECENTLY EXPANDED NORTHWARD AS THE SUBTROPICAL HIGH 
HAS SHIFTED NORTHWARD AND STRENGTHENED. LITTLE CHANGE IN THESE 
CONDITIONS IS EXPECTED THROUGH THE END OF THE PERIOD THU 
MORNING. 

THE PRES GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOWER PRES 
OVER MAINLAND MEXICO IS STRONG ENOUGH TO SUPPORT FRESH NW TO N 
WINDS ALONG THE W COAST OF BAJA CALIFORNIA AND AS FAR S AS 25N. 
SHIP C6QM8 REPORTED 20 KT WINDS NEAR 25N113W AT 0600 UTC AND THE 
0518 UTC ASCAT PASS CONFIRMS WINDS TO 20 KT NEAR THE COAST OF 
BAJA CALIFORNIA. THIS AREA OF WIND IS EXPECTED TO SHIFT W OVER 
THE NEXT DAY OR SO AS DEEP LAYER TROUGHING BUILDS OVER THE GULF 
OF CALIFORNIA AND PUSHES THE TIGHTEST PRES GRADIENT FARTHER W.

A WEAK ANTICYCLONE ALOFT LIES OVER THE GALAPAGOS ISLANDS NEAR 
01N92W AND EXTENDS A RIDGE NORTHWARD TO THE ISTHMUS OF 
TEHUANTEPEC. CONVECTION ALONG THE ITCZ PRIMARILY LIES EITHER 
ALONG THIS RIDGE AXIS OR NEAR THE COAST OF PANAMA WHERE A 
MAXIMUM OF PRECIPITABLE WATER LIES ALONG THE ITCZ. THE UPPER 
PATTERN E OF THIS RIDGE ALSO SPORTS A TROUGH ALONG 86W AND 
ANOTHER WEAK RIDGE OVER THE FORECAST AREA E OF 84W WHICH IS 
GENERATING UPPER DIFFLUENCE ALOFT THAT IS ENHANCING THE ITCZ 
CONVECTION NEAR PANAMA.

AN UPPER TROUGH LIES FROM 28N118W THROUGH 12N112W TO 00N112W. 
THE SOUTHERN STREAM UPPER JET PASSES THROUGH THE TROUGH 
ALOFT...WITH 60-80 KT NORTHWESTERLY WINDS OVER MUCH OF THE AREA 
W OF THE TROUGH AXIS FROM 10N TO 25N AND 40-70 KT SOUTHWESTERLY 
WINDS FOUND N OF 10N BETWEEN THIS TROUGH AXIS AND THE RIDGE AXIS 
TO ITS E DESCRIBED IN THE PARAGRAPH ABOVE. THIS UPPER TROUGH IS 
REFLECTING A SURFACE TROUGH WHICH WAS ANALYZED FROM 11N109W TO 
04N115W. THIS SURFACE TROUGH IS POOLING LOW LEVEL MOSITURE ALONG 
THE ITCZ AND IS RESPONSIBLE FOR SOME HIGHLY ISOLATED CONVECTION 
JUST TO THE E OF ITS AXIS. THE SOUTHWESTERLY UPPER JET IS 
TRANSPORTING CONVECTIVE BLOW OFF NORTHEASTWARD FROM THE ITCZ 
TOWARD CENTRAL MEXICO. 

$$
SCHAUER