000
AXPZ20 KNHC 251515
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT JUL 25 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...

TROPICAL WAVE N OF 05N ALONG 80W MOVING WEST 20 KT. A WEAKENING 
AREA OF MODERATE CONVECTION IS JUST SOUTH OF THE GULF OF PANAMA. 
THE CONVECTION IS MOST LIKELY RELATED TO DIURNAL LAND SEA 
INTERACTION RATHER THAN LINKED TO THE TROPICAL WAVE. OTHERWISE 
NO CONVECTION IS NOTED NEAR THE WAVE.

TROPICAL WAVE FROM 09N92W TO THE GULF OF TEHUANTEPEC MOVING WEST 
18 KT. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM 
OF 12.5N92W. THIS CONVECTION MAY HAVE INITIATED FROM DIURNAL 
LAND SEA INTERACTION BUT IT HAS PERSISTED AND MAY NOW BE LINKED 
TO THE TROPICAL WAVE. THE NUMERICAL FORECAST MODELS SHOW SLOW 
DEVELOPMENT OF CYCLONIC CIRCULATION DURING THE NEXT SEVERAL DAYS 
WITH THIS WAVE.

TROPICAL WAVE FROM 05N TO 16N ALONG 108W MOVING WEST 20 KT. 
SCATTERED MODERATE CONVECTION IS WITHIN ABOUT 90 NM EITHER SIDE 
OF THE AXIS. THE CONVECTION SHOWS NO SIGNS OF BEING ORGANIZED BY 
LOW LEVEL CYCLONIC CIRCULATION AND MAY BE RELATED TO AN UPPER 
TROUGH AXIS THAT IS JUST WEST OF THE WAVE AXIS AND DISCUSSED 
MORE FULLY BELOW.
   
TROPICAL WAVE FROM 05N TO 13N ALONG 115W MOVING WEST 15 KT. 
WIDELY SCATTERED MODERATE CONVECTION IS NEAR THE WAVE AXIS. AS 
WITH THE ABOVE WAVE THE CONVECTION SHOWS NO SIGNS OF BEING 
ORGANIZED BY LOW LEVEL CYCLONIC CIRCULATION AND MAY BE RELATED 
TO AN UPPER SHORTWAVE THAT IS APPROACHING THE WAVE FROM THE 
NORTHWEST.

TROPICAL WAVE FROM 09N140W TO 15N135W MOVING WEST 15 KT. 
ISOLATED MODERATE CONVECTION CONTINUES TO MAINTAIN ALONG THE 
WAVE AXIS BUT SHOWS NO SIGNS OF INCREASING IN COVERAGE OR OF 
ORGANIZATION AROUND LOW LEVEL CYCLONIC FLOW.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...05N77W TO 
06N110W TO 08N140W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS WITHIN 90 NM OF THE POINT 06.5N86.5W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM OF THE POINT 12N130W.
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 
NM OF THE POINT 12.5N138W.

...DISCUSSION...

AN UPPER LEVEL CYCLONIC CIRCULATION HAS MOVED E AND IS NOW 
CENTERED NEAR 34N138W. MULTI LEVEL CLOUDS ARE WITHIN 300 NM OF 
THE CENTER IN THE EAST SEMICIRCLE WITH SCATTERED CONVECTION 
MOSTLY NORTH OF 30N. ASSOCIATED DEEP LAYER MOISTURE IS NORTHWEST 
OF A LINE THROUGH 32N123W TO 20N128W TO 25N140W. EXCEPT AS NOTED 
THIS AREA IS CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. IN THE 
LOWER LEVELS OVERCAST TO BROKEN STRATOCUMULUS IS OBSERVED. THIS 
FEATURE IS FORECAST TO PERSIST THROUGH THE NEXT SEVERAL DAYS AND 
MOVE LITTLE.

AN UPPER LEVEL TROUGH IS FROM 105W TO 125W WITH AN AXIS ALONG 
THE LINE 32N122W TO 25N121W TO 15N115W TO 10N120W. WEST OF THE 
TROUGH AXIS TO THE ABOVE MENTIONED FEATURE THE ATMOSPHERE IS DRY 
AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. NORTH OF 17N IN 
THE SOUTHERLY FLOW EAST OF THE TROUGH AXIS THE MIDDLE AND UPPER 
LEVELS ARE MOIST BUT MOSTLY CLOUD FREE. ONLY PATCHY MIDDLE LEVEL 
CLOUDS WEST OF BAJA CALIFORNIA ARE NOTED. S OF 17N THE 
ATMOSPHERE IS MORE DIFFLUENT IN THE UPPER LEVELS WITH AREAS OF 
CONVECTION WITH SCATTERED CONVECTION. STRONG SOUTHERLY FLOW IS 
CAUSING SHEAR IN THIS AREA SO THE CONVECTION WILL BE INHIBITED 
FROM BECOMING ORGANIZED. 

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS BROAD ANTICYCLONIC 
FLOW OR A FLAT HEIGHT PATTERN. THE AREA SOUTH OF 15N WEST OF 
125W SHOWS DISORGANIZED CONVECTION THAT IS HIGHLY SHEARED BY 
WESTERLY WINDS. THE AREA EAST OF 105W IS DIFFLUENT ALOFT WITH 
WIDESPREAD CONVECTION. THIS AREA IS NOT SHEARED AND PERSISTENT 
CONVECTION MAY BECOME ORGANIZED IN THIS AREA IN THE NEST SEVERAL 
DAYS.

WEAK SURFACE RIDGE IS NORTH OF 15N WEST OF 110W. REMAINDER OF 
THE SURFACE IS ANALYZED AS WEAK TROUGH.

GAP NE TO E WINDS OF 20 TO 25 KNOTS IN AND DOWNSTREAM OF GULF OF 
PAPAGAYO TO NEAR 94W ARE FORECAST TO CONTINUE THROUGH THE NEXT 
SEVERAL DAYS.

LONG PERIOD SOUTHERLY SWELLS OF UP TO 10 FT ARE CROSSING THE 
EQUATOR THROUGH TROPICAL E PACIFIC AND REACHING COAST OF CENTRAL 
AMERICA AND MEXICO. SEAS OF 8 FEET THAT HAD BEEN AS FAR NORTH AS 
NORTHERN BAJA PENINSULA ARE NOW CONFINED TO SOUTH OF ABOUT 17N.

$$
LL