000
AXPZ20 KNHC 241001
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JUL 24 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...SPECIAL FEATURE...
TROPICAL STORM DORA CENTERED NEAR 23.0N 113.7W AT 0900 UTC 
MOVING NW OR 320 DEGREES AT 8 KT. THE MAXIMUM SUSTAINED WINDS 
ARE 35 KT WITH GUSTS TO 45 KT MAINLY WITHIN ABOUT 30 NM OF 
CENTER. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. 
STRONG NORTHERLY SHEAR CONTINUES TO SUPPRESS CONVECTION S OF 
CENTER GENERALLY FROM 45 TO 90 NM OUTWARD. THE CYCLONE IS MOVING 
WESTERLY OVER COOL OCEAN WATERS AND IS EXPECTED TO WEAKEN BELOW 
TROPICAL STORM FORCE LATER TODAY. SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE 
DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 05N83W TO 08N90W WHERE LOW LEVEL 
WINDS INDICATE THAT THE ITCZ AXIS BEGINS AND CONTINUES W TO  
09N109W...THEN TURNS SW TO 05N118W...THEN CONTINUES NW TO 
09N129W AND CONTINUES W TO BEYOND 08N140W. ISOLATED MODERATE AND 
STRONG CONVECTION IS OBSERVED ALONG THE COASTS OF COLOMBIA AND 
PANAMA TO THE N OF 02N E OF 79W.  SIMILAR CONVECTION IS NOTED 
WITHIN 60 NM EITHER SIDE OF A LINE FROM 04N84W TO 09N101W TO 
07N107W TO 11N114W...AND WITHIN 120 NM EITHER SIDE OF A LINE 
FROM 11N129W TO 11N134W TO 09N140W.

...DISCUSSION...
AN UPPER LEVEL TROUGH IS APPROACHING THE NW PORTION OF THE 
DISCUSSION AREA WITH ITS AXIS EXTENDING ALONG 35N141W TO 
30N147W. AN UPPER ANTICYCLONE HAS FORMED ALONG AN UPPER RIDGE 
NEAR 28N120W WITH A RIDGE EXTENDING SW TO BEYOND 18N140W. AN 
INVERTED UPPER TROUGH IS NOTED S OF THIS RIDGE...ALONG 140W 
FROM 12N TO 21N. A SECOND INVERTED UPPER TROUGH IS OVER THE 
DISSIPATING CYCLONE FROM 21N113W TO 27N114W BECOMING EMBEDDED IN 
THE BROADER ANTICYCLONIC FLOW THAT IS DOMINATING THE 
SUBTROPICS.   

AN UPPER CYCLONE IS OVER DEEP TROPICAL PACIFIC AT 04N127W. UPPER 
DIFFLUENCE HAS SET UP BETWEEN THE SOUTHERN PERIPHERY OF THE 
RIDGE AND THE UPPER CYCLONIC FLOW...AND IS ROUGHLY IN PHASE WITH 
THE ITCZ AXIS. THE DEBRIS MOISTURE FROM THE PREVIOUSLY DESCRIBED 
ITCZ CONVECTION IS SPREADING N OVER THE AREA FROM 10N TO 17N 
ALONG 130W...AND FANS OUT OVER THE DEEP TROPICS NEAR 06N139W. 
OTHERWISE THE UPPER LEVELS APPEAR DRY W OF 118W. 

AN UPPER TROUGH EXTENDS W ACROSS THE SOUTHERN GULF OF MEXICO 
THROUGH AN UPPER CYCLONE AT 22N98W...WITH THE TROUGH CONTINUING 
SW OVER THE E PACIFIC ALONG 20N111W TO 13N113W. CONVECTION WAS 
ENHANCED EARLIER OVER NORTHERN OLD MEXICO...TO THE NW OF THIS 
TROUGH AXIS. THE RESULTANT DEBRIS MOISTURE IS ADVECTED W OVER 
THE PACIFIC...MERGING WITH THE DEBRIS MOISTURE FROM DISSIPATING 
TROPICAL CYCLONE DORA...RESULTING IN MOIST UPPER LEVELS OVER THE 
DISCUSSION AREA TO THE N OF 18N BETWEEN 105W AND 117W. SCATTERED 
MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 30 NM OF COAST 
OF MEXICO BETWEEN 96W AND 106W. THE DEBRIS MOISTURE IS SPREADING 
WESTWARD OVER THE PACIFIC FROM THE DISSIPATING CLUSTERS.
  
AN UPPER ANTICYCLONE IS OVER COSTA RICA WITH THE ENVELOPE OF 
ANTICYCLONIC FLOW ENHANCING THE PREVIOUSLY MENTIONED ISOLATED 
TSTMS ALONG THE COASTS OF COLOMBIA AND PANAMA AND OVER THE 
PACIFIC JUST TO THE S OF THE MONSOON TROUGH AXIS. THE DEBRIS 
MOISTURE COVERS THE AREA N OF 04N E OF 89W.

AT THE LOW LEVELS A RIDGE EXTENDS FROM 32N140W TO 20N115W...WITH 
ASSOCIATED TRADES MAXING AT 15 KT. CROSS EQUATORIAL SE 
SWELLS...RESULTING IN SEAS TO 9 FT...ARE PROPAGATING NW ACROSS 
THE WATERS SW OF A LINE FROM 14N140W TO THE EQUATOR AT 
112W...MIXING WITH NE TRADE SWELL TO THE N OF 10N BETWEEN 132W 
AND 140W. SOUTHERLY SWELL IS DOMINATE OVER THE MOST OF THE 
PACIFIC WATERS EXCEPT TO THE N OF 20N W OF 130W WHERE NE SWELL 
AROUND THE LOW LEVEL RIDGE HAS THE LARGEST CONTRIBUTION TO THE 
SEA STATE.

GAP WINDS...NE TRADES OVER THE W CARIBBEAN ARE EXPECTED TO 
CONTINUE TO SURGE THROUGH THE GULF OF PAPAGAYO AT 15-20 KT 
THROUGH TONIGHT...THEN DIMINISH TO 10-15 KT LATE MON. 
NORTHERLY WINDS ARE EXPECTED TO SURGE INTO THE GULF OF 
TEHUANTEPEC AROUND SUNRISE THIS MORNING...AND PULSE THROUGH TUE 
MORNING WITH THE STRONGEST EVENTS JUST AFTER SUNRISE EACH 
MORNING.

$$
NELSON