000
AXPZ20 KNHC 150928
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE APR 15 2008

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 
0800 UTC.

...ITCZ...
ITCZ CENTERED ALONG 2N71W 9N105W 5N130W 4N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION FROM 9N TO 14N BETWEEN 100W 
AND 113W. SCATTERED MODERATE CONVECTION FROM 3N TO 6N BETWEEN 
110W AND 117W WITH CLUSTERS WITHIN 75 NM OF THE ITCZ AXIS W OF 
120W. 

...DISCUSSION...
E OF 110W...
LATEST QUIKSCAT PASS SHOWED THE STORM CONDITIONS IN THE GULF OF 
TEHUANTEPEC HAVE WEAKENED TO GALE FORCE AS COLD AIR ADVECTION 
ABATES AND STRONG SURFACE HIGH PRES WEAKENS OVER THE GULF OF 
MEXICO. SST'S WILL BE SLIGHTLY COOLER AS WELL OVER GULF OF 
TEHUANTEPEC DUE TO RECENT UPWELLING...INHIBITING MIXING OF 
STRONGER WINDS TO THE SURFACE. GALE CONDITIONS WILL END LATE TUE 
AS CONDITIONS MODERATE. FURTHER SOUTH...FRESH WINDS CONTINUE TO 
BLOW THROUGH THE GULF OF PAPAGAYO...WITH 20 KT NOTED ON THE 
LATEST QUIKSCAT PASS. A WEAKENING SURFACE TROUGH REMAINS 
EMBEDDED WITHIN THE ITCZ ALONG 97W WITH SCATTERED THUNDERSTORMS 
DEVELOPING WITHIN 90 NM OF THE AXIS. AN E/W UPPER RIDGE AXIS 
EXTENDS FROM THE CARIBBEAN ACROSS CENTRAL AMERICA TO 16N115W AND 
UPPER LEVEL DIFFLUENCE IS ENHANCING THE CONVECTION N OF THE 
ITCZ. 

W OF 110W...
UPPER RIDGE IS EVIDENT FROM 23N120W NE TO OVER THE N BAJA 
PENINSULA WITH A WEAK SHORT WAVE TROUGH DIGGING INTO THE 
SOUTHWEST U.S. THE UPPER RIDGE IS BLOCKING A STRONGER UPPER 
TROUGH DIGGING INTO THE NW U.S. PACIFIC COAST. ANOTHER WEAK 
SHORT WAVE NE OF HAWAII ALONG THE NE PORTION OF THE REGION AND 
HAS MERGED WITH A SECOND UPPER TROUGH TO FORM A CUT-OFF UPPER 
LOW JUST W OF 140W. UPPER RIDGE BEHIND THE TROUGH DIGGING INTO 
THE U.S. NW COAST IS SUPPORTING A 1043 MB SURFACE HIGH N OF 40N 
EXTENDING A SURFACE RIDGE N OF 20N W OF 120W. THE PERSISTENT 
TIGHT GRADIENT SE OF THIS HIGH IS SUPPORTING AN AREA OF FRESH TO 
STRONG NE FLOW GENERALLY W OF 120W AND N OF 15N...AS WELL AS 
MODEST TRADE FLOW FURTHER S. LITTLE CHANGE IS EXPECTED THROUGH 
48 HOURS. INCREASED NLY FLOW ALONG U.S. WEST COAST ON EAST 
PERIPHERY OF THIS SURFACE HIGH WILL PUSH S OFF THE NRN BAJA 
COAST...ACCOMPANIED BY 8 TO 10 FT NLY SWELL THROUGH MID WEEK.

$$
WALLACE