000
AXPZ20 KNHC 241536
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED JUN 24 2009

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 
1500 UTC.

...SPECIAL FEATURE...
ANDRES WEAKENS TO A TROPICAL DEPRESSION. AT 1500 UTC...TROPICAL 
DEPRESSION ANDRES IS CENTERED NEAR 20.3N 107.7W OR ABOUT 130 
MILES WEST OF CABO CORRIENTES MEXICO...AND ABOUT 230 MILES SE OF 
THE SOUTHERN TIP OF BAJA CALIFORNIA. ANDRES IS MOVING NW AT 7 
KT. ESTIMATED MINIMUM PRESSURE IS 1005 MB. MAXIMUM SUSTAINED 
WINDS ARE 30 KT WITH HIGHER GUSTS. SEE LATEST NHC PUBLIC 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP/WTPZ32 KNHC AND THE 
FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2 WTPZ22 
KNHC FOR MORE DETAILS. NO SIGNIFICANT CONVECTION IS NOTED WITH 
THIS SYSTEM. A 13Z QUIKSCAT PASS SHOWED WINDS TO 30 KT IN THE 
VICINITY OF T.D. ANDRES...INDICATING IT HAS WEAKENED 
CONSIDERABLE OVER THE PAST SEVERAL HOURS. THIS TREND IS EXPECTED 
TO CONTINUE THROUGH TODAY AND TONIGHT...WITH ANDRES BECOMING A 
TROUGH SOUTH OF CABO SAN LUCAS THAT WILL LIKELY KEEP 20 TO 25 KT 
WINDS NEAR THE MOUTH OF THE GULF OF CALIFORNIA AND NEAR THE 
SOUTHERN TIP OF BAJA THROUGH THU. 

...ITCZ...
AXIS IS ALONG 06N77W TO 05N85W TO 13N110W TO 06N140W. SCATTERED 
MODERATE CONVECTION N OF THE AXIS TO THE CENTRAL AMERICAN 
COAST...W OF 90W. SCATTERED MODERATE CONVECTION WITHIN 60 NM N 
OF AXIS BETWEEN 95W AND 97W. SCATTERED MODERATE CONVECTION 
WITHIN 120 NM S OF AXIS BETWEEN 110W AND 125W.

...DISCUSSION...
AN UPPER LEVEL LOW IS STARTING TO CUT OFF NEAR 32N125W...AS 
STRONG JET ENERGY MOVE EASTWARD ACROSS THE NORTHEAST PACIFIC. 
THIS FEATURE IS PART OF AN UPPER TROUGH EXTENDING SOUTHWEST 
TOWARD 25N140W...THEN FURTHER WEST TO HAWAII. THE CUT OFF UPPER 
LOW WILL SHIFT SLOWLY EAST INTO THE SW UNITED STATES THROUGH 
FRI...AHEAD OF A MID/UPPER RIDGE NE OF HAWAII. THE NET IMPACT OF 
ALL THIS WILL BE MINIMAL AT THE SURFACE...BASICALLY A 1028 MB 
SURFACE HIGH PRES AREA CENTERED NEAR 35N145W WILL SHIFT 
EASTWARD...MAINTAINING AN AREA OF FRESH TRADE WINDS MAINLY N OF 
15N W OF 130W. THIS WILL MAINTAIN STRONG WINDS ALONG THE 
CALIFORNIA COAST...PROMPTING NORTHERLY SWELL TO SLIP SOUTH OF 
32N OVER THE NEXT COUPLE OF DAYS GENERALLY N OF 25N W OF 115W.

FURTHER SOUTH...A 05Z ASCAT PASS SHOWED PERSISTENT 20 KT 
SOUTHERLY WINDS CONVERGING INTO THE ITCZ...THE LIKELY CULPRIT 
RESPONSIBLE FOR THE ONGOING CONVECTION BETWEEN 110W AND 125W. 
THE ASCAT ALSO SHOWED CYCLONIC TURNING RELATED TO A LOW PRES 
EMBEDDED IN THE ITCZ NEAR 11N121W. THIS FEATURE HAS AN ESTIMATED 
PRESSURE OF 1010 MB...AND HAS BEEN MOVING SLOWLY EASTWARD OVER 
THE PAST COUPLE OF DAYS. GLOBAL MODELS SUGGEST IT WILL EMERGE NE 
OUT OF THE ITCZ OVER THE NEXT COUPLE OF DAYS...BUT NOT DEVELOP 
INTO A TROPICAL CYCLONE. 

FURTHER EAST ALONG THE ITCZ...AN UPPER TROUGH EXTENDS FROM THE 
NW ATLANTIC INTO THE NW CARIBBEAN. A SMALL UPPER LEVEL CYCLONE 
IS NOTED ON WATER VAPORY IMAGERY OVER HONDURAS AT THE TAIL END 
OF THIS TROUGH. UPPER DIVERGENCE ASSOCIATED WITH THIS FEATURE IS 
INTERACTING WITH MODEST CONVERGENCE INTO THE ITCZ...AS WELL AS 
EARLY MORNING DRAINAGE FLOW OFF THE CENTRAL AMERICAN COAST TO 
IGNITE CLUSTERS OF CONVECTION ALONG AND NORTH OF THE ITCZ 
GENERALLY E OF 95W. 

SEAS OVER 8 FT ARE STILL LIKELY WITHIN 360 NM SOUTH OF THE DYING 
ANDRES...BUT THIS WILL SUBSIDE THROUGH THU. EXPECT SEAS AROUND 8 
FT NEAR THE LOW CURRENTLY AT 11N121W THROUGH FRI...BUT ONLY WITH 
60 NM ON THE SE SIDE OF THE LOW.
 
$$
CHRISTENSEN