000
AXPZ20 KNHC 242130
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JUN 24 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...
TROPICAL DEPRESSION ANDRES WAS DOWNGRADED TO A REMNANT LOW AT 
1800 UTC...AND THE LAST ADVISORY WAS ISSUED BY THE NATIONAL 
HURRICANE CENTER AT THIS TIME. THE REMNANTS OF ANDRES ARE 
PRODUCING SOME CLOUDINESS WITH EMBEDDED LIGHT TO MODERATE RAIN 
OVER PARTS OF NAYARIT AND SINALOA AND ARE ANALYZED AS A SURFACE 
TROUGH FROM SOUTHERN BAJA CALIFORNIA TO NEAR 20N106W. AN 
EARLIER QSCAT PASS INDICATED SW TO S WINDS OF 20 KT BETWEEN THE 
TROUGH AND THE MEXICAN COASTLINE NEAR THE MOUTH OF THE GULF OF 
CALIFORNIA...BUT THESE WINDS ARE EXPECTED TO DIMINISH IN ABOUT 
24 HOURS OR LESS. SEAS AROUND 8 FT ARE STILL LIKELY WITHIN 360 
NM SOUTH OF THE REMNANT OF ANDRES...BUT THESE SHOULD ALSO 
GRADUALLY SUBSIDE.

...ITCZ...
THE ITCZ AXIS IS ALONG 07N78W TO 08N95W TO 12N118W TO 05N140W. 
SCATTERED MODERATE CONVECTION IS NEAR 09N96W. SIMILAR CONVECTION 
IS NOTED FROM 09N TO 12N BETWEEN 110W AND 120W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 80 NM SE 
SEMICIRCLE OF LOW CENTER NEAR 11N121W. A DIFFLUENT PATTERN ALOFT 
IS ENHANCING THE CONVECTIVE ACTIVITY BETWEEN 110W AND 125W.

...DISCUSSION...
ALOFT...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...A 1029 MB SURFACE HIGH PRES AREA CENTERED NEAR 
35N150W HAS A RIDGE EXTENDING INTO THE FORECAST TO NEAR 20N112W. 
THIS FEATURE IS PRODUCING AN AREA OF FRESH TRADE WINDS MAINLY N 
OF 15N W OF 130W. THE RIDGE IS FORECAST BY THE COMPUTER MODELS 
TO STRENGTHEN ON FRI INCREASING WINDS AND SEAS GENERALLY N OF 
25N W OF 115W.

FURTHER SOUTH...A 1425 UTC QSCAT PASS SHOWED PERSISTENT 20 KT 
SOUTHERLY WINDS CONVERGING INTO THE ITCZ AND HELPING TO INDUCE 
THE ABOVE MENTIONED CONVECTION BETWEEN 110W AND 125W. THE QSCAT 
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. WINDS OF 20 KT ARE EXPECTED TO PERSIST WITHIN 
180 NM SE AND 90 NM NW SEMICIRCLES OF THE LOW DURING THE NEXT 24 
HOURS. ALSO...EXPECT SEAS AROUND 8 FT NEAR THE LOW CENTER. 

FURTHER EAST ALONG THE ITCZ...AN INVERTED TROUGH EXTENDING FROM 
CENTRAL AMERICA INTO THE EPAC ALONG 89W/90W IS SUPPORTING SOME 
CONVECTION ALONG THE ITCZ E OF 110W.  

 
$$
GR