000
AXPZ20 KNHC 010312
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT AUG 01 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...TROPICAL WAVES...
TROPICAL WAVE JUST ENTERED E PAC NOW ALONG 80W N OF 02N MOVING W 
AT 20 KT IS RUNNING UNDER FAVORABLE ENVIRONMENT ALOFT IN NRN 
HALF WITH SCATTERED CONVECTION WITHIN 240 NM STILL IN THE 
CARIBBEAN.  SRN PART OVER E PAC REMAINS UNDER ADVERSE NE SHEAR 
WITH LITTLE CONVECTION AS A RESULT.  WAVE SHOULD BE GETTING INTO 
A LESS ANTAGONISTIC ENVIRONMENT AND EXPECTED TO INCREASE DEEP 
CONVECTION WITHIN NEXT 24-48 HRS.  MODEL GUIDANCE SOLUTION 
APPEAR QUITE UNCERTAIN OF ANY DEVELOPMENT BEYOND 48 HRS.    

TROPICAL WAVE FROM 04N-17N ALONG 106W MOVING W 15 KT.  
UNFAVORABLE UPPER ENVIRONMENT FINALLY TOOK ITS TOLL IN WAVE 
CONVECTION AND NOW BARELY HAS ISOLATED TSTMS RUNNING FASTER THAN 
WAVE AXIS THUS SEPARATING THEM APART.  WAVE APPROACHING AREA 
OF MORE BENIGN UPPER CONDITIONS WHICH COULD LIKELY LEAD TO 
INCREASED CONVECTION WITHIN NEXT 48 HRS.  MODEL GUIDANCE PLACES 
1011 MB LOW PRES CENTER IN VICINITY OF 113W WITHIN 24 HRS AND 
NEAR 115W WITHIN 48 HRS.   

TROPICAL WAVE FROM 04N-17N ALONG 125W MOVING W 15 KT.  SCATTERED 
MODERATE CONVECTION WITHIN 90 NM W OF WAVE AXIS FROM 07N-10N. 
WAVE APPROACHING MID-UPPER LEVEL CYCLONIC VORTEX WITH ABUNDANT 
MOISTURE AVAILABLE FOR CONVECTION...BUT STRONG NE SHEAR ON N 
HALF OF WAVE AXIS SHOULD DAMPEN ANY SIGNIFICANT DEVELOPMENT OF 
DEEP CONVECTION.  GUIDANCE SOLUTION DOES NOT APPEAR TO HAVE A 
GOOD HANDLE ON WHETHER CYCLONIC ORGANIZATION IS WARRANTED...BUT 
IF ANYTHING DOES DEVELOP IT IS LIKELY TO BE WELL AFTER 48 HRS 
WHEN THE UPPER CYCLONE EFFECTS ARE DIMINISHED.

...ITCZ...
AXIS ALONG 07N78W TO 09N98W TO 08N110W TO 11N123W TO 09N134W TO 
10N140W.  SCATTERED MODERATE CONVECTION WITHIN 180 NM OF AXIS 
FROM 90W-115W.  SCATTERED MODERATE CONVECTION WITHIN 150 NM S OF 
AXIS W OF 131W.

...DISCUSSION...
LASTING EFFECTS OF T.S. LANA STILL LINGER OVER FORECAST WATERS  
W OF 138W FROM 15N-18N AS FRESH NE WINDS ARE STILL NOTED...BUT 
EXPECTED TO DIMINISHED WITHIN 12 HRS.  FURTHER INFORMATION ON 
T.S. LANA IN LATEST PUBLIC ADVISORY FROM CENTRAL PACIFIC 
HURRICANE CENTER UNDER AWIPS/WMO HEADERS MIATCPEP1/WTPZ31.

ELSEWHERE OVER N WATERS...SURFACE HIGH PRES CENTER 1027 MB AT 
37N145W HAS MODERATE TO STRONG SUBSIDENCE AND DRY STABLE AIR AT 
MID AND UPPER LEVELS W OF 120W.  RIDGE EXTENDS TO 18N110W SHOULD 
DRIFT W DURING NEXT 24 HRS EASING GRADIENT AS T.S. LANA MOVES W 
EFFECTIVELY DIMINISHING FRESH NE TRADES LEFT W OF 138W.  

FRESH BREEZE ACROSS GULF OF PAPAGAYO DIMINISHES AS WEAK SURFACE 
TROUGH MOVES W AWAY FROM REGION...BUT REESTABLISHES AGAIN WITHIN 
48 HRS ONCE WAVE AXIS MOVES W AND STRONG BREEZE DOMINATES WRN 
CARIBBEAN.

CROSS EQUATORIAL SW SWELLS WITH SIGNIFICANT WAVE HEIGHTS TO 8 FT 
ENTER SOUTHERN CENTRAL SECTION OF BASIN AND EXPANDS TO S OF 10N 
BY END OF FORECAST PERIOD.

$$
WALLY BARNES