000
AXPZ20 KNHC 171541
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JUL 17 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.

...TROPICAL WAVES...
A TROPICAL WAVE HAS ENTERED THE EPAC ACROSS CENTRAL AMERICA AND 
CURRENTLY EXTENDS ALONG 92W/93W N OF 04N TO THE MEXICO/GUATEMALA 
BORDER. NO DEEP CONVECTION IS ASSOCIATED WITH THIS WAVE THAT  
HAS BEEN DRAGGING CONSIDERABLE AMOUNTS OF AFRICAN DUST WITH IT.  
 
A TROPICAL WAVE IS ALONG 118W FROM 04N-15N MOVING W AT 15 KT. 
ISOLATED MODERATE CONVECTION IS WHERE THE WAVE MEETS THE ITCZ 
AXIS. 

...ITCZ...
THE ITCZ AXIS IS ALONG 07N78W TO 10N110W TO 11N125W TO 10N140W. 
SCATTERED MODERATE ISOLATED STRONG N OF 05N E OF 82W INCLUDING 
THE GULF OF PANAMA. CLUSTER OF MODERATE TO ISOLATED STRONG 
WITHIN 60 NM OF 12.5N107W. SIMILAR CONVECTION IS WITHIN 180 NM N 
OF AXIS BETWEEN 97W AND 105W. SCATTERED MODERATE FROM 07N TO 12N 
BETWEEN 118W AND 125W.

...DISCUSSION...
A MID/UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER NW 
MEXICO EXTENDING A RIDGE MAINLY SOUTH OVER THE FORECAST AREA 
PARTICULARLY N OF 18N E OF 122W. ANOTHER RIDGE...ANCHORED ON AN 
UPPER-LEVEL HIGH LOCATED W OF AREA ENTERS THE FAR WEST NEAR 
15N141W THEN CONTINUES NE TO 25N132W PRODUCING A VERY DRY AND 
STABLE ATMOSPHERE ALOFT. A DEEP-LAYERED TROUGH IS APPROACHING 
THE NW CORNER OF THE AREA. UPPER SWLY FLOW AHEAD OF THIS TROUGH 
IS TRANSPORTING MID TO UPPER LEVEL MOISTURE FROM THE TROPICS 
INTO THE NW PORTION OF THE FORECAST REGION. AN INVERTED TROUGH 
EXTENDS FROM THE COAST OF MEXICO NEAR 18N103W TO 08N108W. 
CONVECTION IS ENHANCED NEAR 12.5N107W...AND ALONG THE ITCZ.

A SWIRL OF LOW CLOUDS...ANALYZED A 1009MB LOW NEAR 20N126W...IS 
ASSOCIATED WITH THE REMNANTS OF DOLORES. NE TO E WINDS OF 20 TO 
25 KT AND SEAS OF UP TO 11 FT ARE STILL NOTED WITHIN 240 NM N 
SEMICIRCLE. THESE CONDITIONS ARE EXPECTED TO GRADUALLY DIMINISH 
AS THE REMNANTS OF DOLORES CONTINUES TO MOVE W-NW UNTIL 
DISSIPATION. A SFC RIDGE TO THE NE OF DOLORES WILL PRODUCE FRESH 
NW BREEZE ALONG W COAST OF BAJA CALIFORNIA THROUGH THE FORECAST 
PERIOD. PRES GRADIENT BETWEEN A RIDGE TO THE N AND WHAT IS LEFT 
OF CARLOS PRESENTLY JUST W OF REGION IS PRODUCING AN AREA OF 
FRESH TRADE WINDS FROM 13N TO 22N W OF 130W. 

GAP WINDS...EASTERLY TRADES AT 20 TO 25 KT...WITH SEAS TO 10 
FT...ARE EXPECTED TO CONTINUE TO SURGE THROUGH THE GULF OF 
PAPAGAYO FOR AT LEAST 2 MORE DAYS. THESE WINDS ARE EXPECTED TO 
EXTEND WESTWARD TO ALONG 110W IN ABOUT 24 HOURS. FRESH TO STRONG 
NLY WINDS ARE ALSO EXPECTED TO SURGE THROUGH THE GULF OF 
TEHUANTEPEC DURING THE NEXT 48 HOURS. A RECENT QSCAT PASS HAS 
CONFIRMED THIS TEHUANTEPEC EVENT...LIKELY ENHANCED BY AN 
APPROACHING TROPICAL WAVE.  

CROSS EQUATORIAL SOUTHEASTERLY AND SOUTHWESTERLY SWELLS AND 
SOUTHERLY LOW LEVEL FLOW AT 15 TO 20 KT WILL RESULT IN SEAS TO 
10 FT SPREADING N OVER THE WATERS S OF 10N W OF THE GALAPAGOS 
ISLANDS TO ALONG 130W THROUGH 48 HOURS. SWLY SWELLS WILL ALSO 
REACH THE AREA S OF 04N E OF THE GALAPAGOS ISLANDS IN ABOUT 48 
HOURS. 

$$
GR