000
AXPZ20 KNHC 211521
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JUN 21 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 FEATURES...

LOW NEAR 15N100W 1005 MB MOVING WEST NORTHWEST 5 KNOTS. BROAD 
CYCLONIC TURNING CAN BE SEEN IN A LARGE AREA SURROUNDING THE 
SYSTEM. CONVECTION NEAR THE CENTER HAS INCREASED SINCE YESTERDAY 
WITH SCATTERED MODERATE TO STRONG CONVECTION WITHIN 180 NM OF 
THE POINT 14N102.5W. THE CONVECTION NEAREST THE CENTER IS 
ORGANIZING IN A BAND WITHIN 120 NM OF THE SOUTHERN SEMICIRCLE OF 
THE CIRCULATION. OTHER AREAS OF CONVECTION WELL EAST OF THE 
CENTER ARE ALONG AND OFFSHORE THE COAST FROM WESTERN EL SALVADOR 
TO THE GULF OF TEHUANTEPEC WITH SCATTERED MODERATE ISOLATED 
STRONG WITHIN 180 NM OF 13N92.5W. HEAVY RAINS ARE LIKELY ALONG 
THE COAST AND WILL BE ENHANCED INLAND DUE TO OROGRAPHIC 
EFFECTS.  UPPER LEVEL OUTFLOW OVER THIS REGION IS PROVIDING AN 
ENVIRONMENT FAVORABLE FOR CONTINUED DEEP CONVECTION AND THE LOW 
MAY BECOME A TROPICAL CYCLONE IN THE NEXT 24 HOURS.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...05N77W TO 
09N105W TO 08N120W TO 05N140W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN 180 NM OF THE POINT 05.5N80W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 
06.5N88.5W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE 
ITCZ FROM 100W TO 108W. SCATTERED MODERATE TO STRONG CONVECTION 
IS WITHIN 60 NM OF THE ITCZ FROM 121W TO 125W AND FROM 129W TO 
135W.

OTHER AREA OF CONVECTION OUTSIDE THE ITCZ IS SCATTERED MODERATE 
TO STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 18N105W. 

...DISCUSSION...

WEAK MIDDLE LEVEL RIDGE IS NORTH OF 20N WEST OF 130W. RIDGE IS 
FORECAST TO WEAKEN AND BY MONDAY THIS AREA WILL BE PART OF A 
BROAD TROUGH OVER THE NORTHERN PART OF THE AREA. THE AREA IS DRY 
AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS WITH MOSTLY 
OVERCAST STRATOCUMULUS IN THE LOWER LEVELS EXCEPT FOR SCATTERED 
STRATOCUMULUS NORTH OF 29N WEST OF 135W.

LARGE TROUGH IS OVER THE AREA ELSEWHERE NORTH OF THE ITCZ AND 
WEST OF A LINE FROM 32N103W TO 20N109W TO THE ITCZ NEAR 118W.
AN AREA OF UPPER LEVEL DIFFLUENCE WITHIN 300 NM OF THE POINT 
09N129W IS MOIST IN THE DEEP LAYER WITH MULTI LEVEL OVERCAST 
CLOUDS AND ENHANCED CONVECTION INCLUDING WITHIN THE ITCZ. A 
SURFACE LOW IS CENTERED NEAR 10N129W 1009 MB AND IS MOVING 
NORTHEAST 5 TO 10 KNOTS. SCATTERED MODERATE TO STRONG CONVECTION 
IS WITHIN THE AREA FROM 09N TO 11.5N FROM 126W TO 132W 
ASSOCIATED WITH THE LOW. THIS LOW HAS A LOW CHANCE OF BECOMING A 
TROPICAL CYCLONE. ELSEWHERE WITHIN THE BROAD TROUGH THE 
ATMOSPHERE IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS 
WITH OVERCAST STRATOCUMULUS NORTH OF 20N AND SCATTERED TO BROKEN 
STRATOCUMULUS FROM 15N TO 20N IN THE LOWER LEVELS.

DIFFLUENT UPPER FLOW EAST OF THE BROAD TROUGH IS ASSOCIATED WITH 
A LARGE AREA OF MULTI LEVEL CLOUDS AND EMBEDDED AREAS OF 
CONVECTION THAT EXTENDS EAST TO CENTRAL AMERICA MOSTLY NORTH OF 
THE ITCZ. THIS AREA INCLUDES THE LOW MENTIONED IN THE SPECIAL 
FEATURES SECTION. 

A MODERATE SURFACE RIDGE IS NORTH OF 15N WEST OF 115W. ELSEWHERE 
EXCEPT AS MENTIONED ABOVE A BROAD TROUGH IS ANALYZED AT THE 
SURFACE.
 
$$
LL