000
AXPZ20 KNHC 231515
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JUL 23 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 88W MOVE W AT 25 KT. WEAK UPPER 
LEVEL ANTICYCLONE IS OVER THE SYSTEM. SCATTERED MODERATE 
CONVECTION IS WITHIN 90 NM OF 12N90W. THE CONVECTION HAS BEEN 
DECREASING DURING THE LAST SIX HOURS.
   
TROPICAL WAVE FROM 05N TO 15N 100W MOVE W AT 20 KT. SOUTHERLY 
SHEAR IS OVER THE SYSTEM. A NARROW BAND OF MODERATE CONVECTION 
IS WITHIN 45 NM EITHER SIDE OF A LINE FROM 15N97W TO 10N102.5W. 
THE CONVECTION SHOWS NO SIGNS OF CYCLONIC ORGANIZATION. THE WAVE 
IS MOVING TOWARD AN UPPER LEVEL TROUGH AND CONTINUED SOUTHERLY 
SHEAR WILL INHIBIT DEVELOPMENT.

TROPICAL WAVE FROM 05N TO 15N ALONG 128W/130W MOVE W AT 15 KT.
WESTERLY SHEAR IS OVER THE SYSTEM. ONLY ISOLATED CONVECTION IS 
NEAR THE WAVE. OTHER ISOLATED CONVECTION IS EAST OF THE AXIS AND 
IS IN NE TO SW NARROW BANDS THAT SHOW NO SIGNS OF ORGANIZATION.
 
...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...06N77W TO 
07N105W TO 08N140W. ONLY SMALL ISOLATED AREAS OF MODERATE 
CONVECTION IS NOTED ACROSS THE AREA.

...DISCUSSION...

DEEP LAYER CYCLONIC CIRCULATION IS NORTHWEST OF THE AREA 
CENTERED NEAR 32N147W. ASSOCIATED SOUTHERLY FLOW IS WEST OF 
32N120W TO 23N125W TO 18N140W. THIS AREA IS MOIST IN THE MIDDLE 
AND UPPER LEVELS. THE AREA IS CLOUD FREE IN THE MIDDLE AND UPPER 
LEVELS EXCEPT FOR OVERCAST HIGH CLOUDS FROM 23N TO 28N W OF 
136W. IN THE LOWER LEVELS OVERCAST STRATOCUMULUS IS OBSERVED 
EXCEPT FOR CLEAR SKIES S OF 23N WEST OF 135W. THIS FEATURE IS 
FORECAST TO PERSIST THROUGH THE NEXT SEVERAL DAYS AND DRIFT A 
LITTLE EAST.

AN UPPER LEVEL TROUGH IS ALONG THE LINE 20N115W TO 10N133W. 
WITHIN 550 NM NW OF THIS LINE THE ATMOSPHERE IS DRY AND CLOUD 
FREE IN THE MIDDLE AND UPPER LEVELS. A NARROW BAND OF MODERATE 
MOSTLY ISOLATED CONVECTION IS ALONG THE TROUGH AXIS LINE.

A MORE SIGNIFICANT TROUGH IS LOCATED SOUTHWEST OF MEXICO FROM 
100W TO 15W FROM THE ITCZ TO 20N. A WEAK CYCLONIC CIRCULATION 
CENTER IS NOTED NEAR 12.5N107W. ASSOCIATED CONVECTION IS LOCATED 
EAST OF 106W IN THE SOUTHERLY FLOW. THIS CONVECTION REGION IS 
ALSO ASSOCIATED WITH THE TROPICAL WAVE ALONG 100W. OTHERWISE THE 
TROUGH AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER 
LEVELS.

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS BROAD ANTICYCLONIC 
FLOW OR FLAT HEIGHT PATTERN.

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 KNOTS IN AND JUST DOWNSTREAM OF GULF OF 
PAPAGAYO ARE FORECAST TO BEGIN TONIGHT.

LONG PERIOD SOUTHERLY SWELLS OF 10 TO 12 FT ARE CROSSING THE 
EQUATOR THROUGH TROPICAL E PACIFIC AND REACHING COAST OF CENTRAL 
AMERICA LATE TONIGHT. SEAS OF 8 FEET ARE FORECAST AS FAR NORTH 
AS CENTRAL BAJA PENINSULA LATE FRI.

$$
LL