000
AXPZ20 KNHC 201525
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT JUN 20 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 IS RELOCATED TO NORTH OF 04N ALONG 106W AND IS 
ESTIMATED TO BE MOVING W 10 TO 15 KT. THE POSITION IS BASED ON 
SATELLITE WINDS. AN AREA OF CONVECTION HAS DEVELOPED NEAR THE 
WAVE AXIS WITH SCATTERED MODERATE TO STRONG CONVECTION WITHIN 90 
NM OF THE POINT 16.5N106.5W. 

A LARGE AREA OF CONVECTION PREVIOUSLY ATTRIBUTED TO THE WAVE IS 
NOW WELL EAST OF THE WAVE AXIS AND IS NOT ASSOCIATED WITH THE 
WAVE. THIS AREA IS ASSOCIATED WITH A BROAD TROUGH WITH SCATTERED 
MODERATE TO STRONG CONVECTION NORTH OF 10N FROM 90W TO 103W.
A TROPICAL CYCLONE MAY FORM WITHIN THIS BROAD AREA BUT THE 
CONVECTION DOES NOT SHOW ORGANIZATION OR CONSOLIDATION AT THIS 
TIME.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...04N77W TO 
07N100W TO 12N110W TO 07N120W TO 06N130W TO 04N140W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 120 NM OF THE POINT 
04N78.5W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS 
WITHIN 120 NM OF THE POINTS 05.5N89.5W AND ALSO 07N94.5W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE 
POINT 07.5N101W. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 75 NM EITHER SIDE OF THE ITCZ AXIS FROM 110W TO 119W.
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN THE AREA FROM 
04N TO 09N FROM 128W TO 134W.

...DISCUSSION...

MIDDLE AND UPPER RIDGE IS NORTH OF 20N WEST OF 125W. RIDGE IS 
FORECAST TO WEAKEN THROUGH THE NEXT COUPLE OF DAYS AND BY MONDAY 
THIS AREA WILL BE PART OF A BROAD TROUGH THAT DEVELOPS OVER THE 
NORTHERN PART OF THE AREA. THE AREA IS DRY AND CLOUD FREE IN THE 
MIDDLE AND UPPER LEVELS WITH OVERCAST TO BROKEN STRATOCUMULUS IN 
THE LOWER LEVELS.

WELL DEFINED SHORTWAVE IS OVER THE NORTHEAST PART OF THE PACIFIC 
OCEAN AREA. THE TROUGH IS NORTH OF 25N FROM 105W TO 120W. THE 
AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. IN 
THE LOWER LEVELS MOSTLY OVERCAST STRATOCUMULUS IS OBSERVED. THE 
TROUGH EXTENDS SOUTH OF 25N IN A WEAKER FORM AND COVERS A BROAD 
AREA NORTH OF THE ITCZ FROM ABOUT 110W TO 125W. DIFFLUENT UPPER 
FLOW EAST OF BOTH THE STRONG AND WEAK PART OF THE TROUGH COUPLED 
WITH SOUTHERLY FLOW IS ADVECTING A MOISTURE PLUME FROM THE ITCZ 
NORTHWARD OVER A BROAD AREA EAST OF A LINE FROM NEAR 32N105W TO 
25N105W TO THE ITCZ NEAR 122W. OVER THE PACIFIC PART OF THIS 
AREA A LARGE UPPER DIFFLUENCE AREA WITH MULTI LEVEL CLOUDS AND 
EMBEDDED AREAS OF CONVECTION EXTENDS TO 85W. THE MOISTURE PLUME 
IS MUCH NARROWER OVER MEXICO AND DRY AIR IS ADVECTION FROM THE 
GULF OF MEXICO NORTH OF 20N. THE PLUME OVER MEXICO IS ONLY ABOUT 
200 NM WIDE. THIS AREA INCLUDES THE TROPICAL WAVE AND THE BROAD 
SURFACE TROUGH MENTIONED IN THE ITCZ SECTION.

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS ANALYZED AS A WEAK 
HEIGHT PATTERN.

A MODERATE SURFACE RIDGE IS NORTH OF 22N WEST OF 130W WITH A 
WEAKER RIDGE ELSEWHERE NORTH OF 14N WEST OF 112W. ELSEWHERE 
EXCEPT AS MENTIONED ABOVE A BROAD TROUGH IS ANALYZED AT THE 
SURFACE.
 
$$
LL