000
AXPZ20 KNHC 290918
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED APR 29 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...04N77W TO 
04N115W TO 03N130W TO 04N140W. CONVECTION HAS INCREASED ALONG 
THE ITCZ IN THE LAST SIX HOURS MOSTLY WEST OF 115W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF 04.5N81.5W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 
NM OF THE POINT 04N95W. SCATTERED MODERATE TO STRONG CONVECTION 
IS WITHIN THE AREA FROM 08N TO 09N FROM 115W TO 118W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 75 NM OF THE POINT 
04.5N123.5W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 
60 NM EITHER SIDE OF THE ITCZ FROM 130W TO 139W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 
05.5N138.5W.
 
...DISCUSSION...

MODERATE WEST TO SOUTHWEST DEEP LAYER FLOW IS NORTH OF A LINE 
FROM THE BIG BEND OF TEXAS TO ACROSS SOUTHERN BAJA CALIFORNIA TO 
23N130W TO 18N140W. A STRONG SHORTWAVE IS WEST OF THE REGION 
WITH A TROUGH AXIS NEAR 148W. THIS SHORTWAVE IS FORECAST TO MOVE 
EAST WITH THE TROUGH AXIS ALONG 140W MIDDAY THURSDAY. THE TROUGH 
WILL CONTINUE EAST BUT BECOME ABSORBED BY THE WESTERLIES NORTH 
OF 28N IN THE LATER PART OF THE WEEK. A DEEP LAYER PLUME OF 
MOISTURE WITH BROKEN HIGH CLOUDS IS WITHIN 500 NM SOUTH AND 
SOUTHEAST OF THE WEST TO SOUTHWEST DEEP LAYER FLOW. ALSO 
ASSOCIATED WITH THE SHORTWAVE IS ANOTHER PLUME OF DEEP LAYER 
MOISTURE WITH MULTI LEVEL OVERCAST CLOUDS WITH EMBEDDED 
CONVECTION WHICH IS AFFECTING THE AREA NORTH OF 23N WEST OF 
132W. AS THE TROUGH MOVES EAST THIS AREA OF WEATHER WILL 
CONTINUE TO MOVE EAST ACROSS THE AREA MOSTLY NORTH OF 23N BUT AS 
THE TROUGH IS ABSORBED THE AREA WILL DIMINISH IN SIZE.

ANOTHER MAINLY UPPER TROUGH IS OVER THE EASTERN PART OF THE AREA 
EAST OF 105W WITH AN AXIS ALONG 97W. TO THE EAST OF THE TROUGH 
AXIS THE SOUTHERLY FLOW IS ADVECTING DEEP LAYER MOISTURE WITH 
MULTI LEVEL BROKEN CLOUDS FROM ITCZ CONVECTION TO OVER CENTRAL 
AMERICA AND EASTERN MEXICO.

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS UNDER BROAD 
ANTICYCLONIC FLOW.

A WEAKENING SURFACE RIDGE IS NORTH OF 12N WEST OF 110W. A 
SURFACE TROUGH ASSOCIATED WITH THE DEEP LAYER TROUGH IS OVER THE 
FAR NORTHWEST PART OF THE AREA WITH ASSOCIATED SCATTERED 
MODERATE CONVECTION N OF 25N W OF 137.5W. REMAINDER OF THE 
SURFACE IS ANALYZED AS A BROAD TROUGH.

GAP NORTHEAST TO EAST WINDS OF 20 TO OCCASIONALLY 25 KNOTS IN THE
GULF OF PAPAGAYO REGION WILL CONTINUE THROUGH WEDNESDAY NIGHT 
THEN DIMINISH TO LESS THAN 20 KT THURSDAY.

$$
LL