000 AXPZ20 KNHC 031550 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT MAY 03 2008 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 1530 UTC. ...ITCZ... ITCZ AXIS FROM 09N83W TO 07N93W TO 07N100W TO 06N120W TO 03N140W. SCATTERED MODERATE CONVECTION WITHIN 120 NM S OF AXIS BETWEEN 82W AND 85W. SCATTERED MODERATE CONVECTION WITHIN 150 NM N AND 90 NM S OF AXIS BETWEEN 91W AND 98W. SCATTERED WEAK CONVECTION FROM 90-210 NM S OF AXIS BETWEEN 133W AND 137W. ...DISCUSSION... W OF 110W... WEAK SHORTWAVE ENERGY COMING OUT OF THE GULF OF ALASKA HAS BEGUN DIGGING INTO A BROAD LONGWAVE TROUGH POSITIONED CLOSE TO THE U.S. WEST COAST. THIS PATTERN SHOULD FAVOR SURFACE LOW PRESSURE DEVELOPING OVER THE SW CONUS THIS WEEKEND...WHILE HIGH PRESSURE TAKES HOLD IN THE WAKE OF THE TROUGH OVER THE NE PACIFIC. THE PRESSURE GRADIENT ALREADY IN PLACE BETWEEN LOW PRESSURE ON THE PLAINS AND HIGH PRESSURE IN THE PACIFIC HAS BEEN CAUSING STRONG NORTHERLY LOW-LEVEL FLOW N OF 26N BETWEEN 118W AND 128W THE LAST FEW DAYS...BUT THESE WINDS HAVE GRADUALLY BEEN DECREASING IN INTENSITY AND COVERAGE. AS THE SHORTWAVE NOW NEAR THE WEST COAST CUTS OFF SW OF THE SOUTHERN CALIFORNIA COAST SUN...A RE- INTENSIFICATION OF NORTHERLY WINDS OFFSHORE THE CALIFORNIA COAST AND NORTHERN BAJA COASTS SHOULD OCCUR...THOUGH THE STRONGEST WINDS ARE EXPECTED TO REMAIN N OF THE AREA. SEAS OF 8 TO 10 FT IN LONG PERIOD NW SWELL COMING OUT OF THE N PACIFIC AND EVEN LONGER PERIOD SW SWELL WITH ORIGINS FROM THE SOUTHERN HEMISPHERE CONTINUE TO AFFECT THE AREA WITHIN A FEW HUNDRED MILES OF THE WEST COAST OF BAJA CALIFORNIA. HOWEVER...SEAS SHOULD BRIEFLY SUBSIDE TO 6 TO 8 FT ACROSS THIS AREA BY SUN BEFORE RE-BUILDING AS A NEW GROUP OF NW SWELL ARRIVES MON AND TUE NEXT WEEK. ELSEWHERE...ENHANCED SURFACE HIGH PRESSURE NE OF HAWAII ARCS SW INTO THE TROPICAL EAST PACIFIC...KEEPING TRADES ABOVE NORMAL IN AN AREA ROUGHLY RUNNING FROM 6 TO 20N W OF 125W. EARLIER QUIKSCAT AND ASCAT PASSES CONTINUE TO SHOW SPOTTY 20 KT WINDS COVERING THIS REGION...WITH SEAS 8 TO 10 FT IN MIXED NE WIND WAVES AND NW SWELL. OVER THE NEXT FEW DAYS...EXPECT THE AREA OF ENHANCED TRADES TO GRADUALLY SHRINK AND SO ALSO THE AFFECTED SEAS. IN FACT...5 TO 7 FT SEAS SHOULD REPLACE THE GREATER THAN 8 FT SEAS...PRIMARILY IN NE WIND WAVES. OTHERWISE...WATER VAPOR IMAGERY AND CLOUD-TRACKED WINDS SHOW A WELL-DEFINED BAND OF ANOMALOUS WESTERLY FLOW ALONG THE EQUATOR EXTENDING FROM THE DATELINE TO 100W. THE ANOMALOUS WESTERLY FLOW OF 20 TO 60 KT IS PRECEDING WHAT WAS EARLIER A WELL-ORGANIZED BURST OF TROPICAL CONVECTION TRACKING FROM THE INDIAN OCEAN INTO THE WESTERN PACIFIC. THIS SIGNAL SHOULD CONTINUE TO MOVE EASTWARD INTO THE EASTERN PACIFIC...THOUGH THE COOLER-THAN- AVERAGE SEA SURFACE TEMPERATURES ASSOCIATED WITH LA NINA SHOULD SQUASH ANY ENHANCED CONVECTION. E OF 110W... A LARGE MID- TO UPPER-LEVEL RIDGE CENTERED JUST W OF CENTRAL AMERICA EXTENDS NW INTO SOUTHERN MEXICO AND THE SW PORTION OF THE GULF OF MEXICO AND DOMINATES MOST OF THE REGION. AT THE SFC...SHIP REPORTS AND EARLIER SCATTEROMETER PASSES SHOWED A BROAD CYCLONIC FLOW SURROUNDING MEXICO...WITH WINDS NO GREATER THAN 10 TO 15 KT. AN EARLIER SCATTEROMETER PASS ALSO SHOWED A WEAK CYCLONIC CIRCULATION WITHIN THE ITCZ NEAR 07N93W...DRIFTING SLOWLY WESTWARD. SCATTERED CONVECTION NEAR THIS FEATURE REMAINS POORLY-ORGANIZED AT THIS TIME...THOUGH INTERESTINGLY AN 1132 UTC QUIKSCAT PASS INDICATED WHAT MIGHT BE A SUBTLE SOUTHERLY SURGE BETWEEN THE EQUATOR AND THE ITCZ. FINALLY...SW SWELL CONTINUES TO ARRIVE ACROSS THE AREA FROM THE SOUTHERN HEMISPHERE...WITH A SEAS RANGING FROM 6 TO 7 FT EXCEPT LOWER NEAR SHORE. MODEL GUIDANCE SHOWS SEAS GRADUALLY SUBSIDING THIS WEEKEND INTO EARLY NEXT WEEK...STILL IN SW SWELL. $$ KIMBERLAIN