000
AXPZ20 KNHC 290955
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUN 29 2010

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 0945 UTC.

...TROPICAL LOWS....

THE REMNANT LOW PRES OF CELIA IS QUASI STATIONARY NEAR 15.5N 
123.5 AND ESTIMATED AT 1007 MB. WINDS ARE 20 TO 25 KT WITHIN 
ABOUT 120 NM OF CENTER. SHOWERS ARE INDICATED WITHIN 60 NM OVER 
THE E SEMICIRCLE AND WITHIN 120 NM OVER THE W SEMICIRCLE. THE 
LOW IS EXPECTED TO GRADUALLY SPIN DOWN AND OPEN INTO A N TO S 
ORIENTATED TROUGH THU NIGHT INTO FRI.

THE REMNANT LOW PRES OF OF DARBY IS CENTERED NEAR 15N97.5W AND 
ESTIMATED AT 1007 MB. SCATTERED MODERATE TO STRONG CONVECTION 
FLARED RECENTLY TO THE SW OF CENTER WITHIN ABOUT 45 NM 14N99W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED 
OVER THE GULF OF TEHAUNTEPEC AND ALSO WITHIN 60 NM OF THE 
MEXICAN COAST BETWEEN 98W AND 101W...POSSIBLY ASSOCIATED WITH A  
TROPICAL WAVE THAT WAS MOVING THROUGH THE AREA THAT IS DIFFICULT 
TO LOCATE THIS MORNING. THE PRES GRADIENT SE OF DARBY IS 
SUPPORTING SW TO W WINDS AT 20 TO 25 KT WITHIN 360 NM S 
SEMICIRCLE. DARBY SHOULD WEAKEN TO AN OPEN TROUGH LATER TODAY 
THEN EXTEND NE TO CARIBBEAN STORM ALEX. THE TROUGH WILL MOVE NW 
IN TANDEM WITH ALEX OVER THE NEXT FEW DAYS. THIS WILL RESULT 
IN A REVERSE TEHUANTEPEC EVENT AS SW WINDS AT 15 TO 25 KT ARE 
EXPECTED SE OF THE DARBY REMNANT TROUGH AND ENHANCED THE 
INTENSIFYING ALEX...WITH CONDITIONS EXPECTED THROUGH AT LEAST 
WED.    

...TROPICAL WAVES...

A TROPICAL WAVE IS N OF ALONG 85W BUT ONLY FLARING CONVECTION 
OVER THE CARIBBEAN AT THE MOMENT.  

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 08N78W 13N96W TO 08N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS OBSERVED FROM 08N TO 12N 
BETWEEN 112W AND 125W AND ALSO ALONG 09N BETWEEN 136W AND 140W.

...DISCUSSION...

AN UPPER CYCLONE IS CENTERED OVER NEW MEXICO NEAR 32N111W WITH A 
TROUGH EXTENDING SW INTO A SMALLER UPPER CYCLONE AT 31N121W WITH 
THE TROUGH CONTINUING SW ALONG 23N124W INTO AN UPPER CYCLONE NOW 
OVER THE REMNANTS OF FORMER TROPICAL CYCLONE CELIA...WITH A 
CONTINUING S TO A BASE AT 10N123W AND ENHANCING ITCZ CONVECTION 
ALONG 11N BETWEEN 120W AND 125W. 

AN UPPER ANTICYCLONE IS CENTERED AT 23N135W WITH A RIDGE 
AMPLIFYING NE TO A CREST AT 33N125W. A RIDGE ALSO EXTENDS SW TO 
OVER THE ITCZ AT 10N147W AND IS ENHANCING CONVECTION ALONG THE 
ITCZ BETWEEN 130W AND 147W WITH THE DEBRIS MOISTURE ADVECTED 
N...BUT REMAINING W OF THE AREA BETWEEN 140W AND 146W. OTHERWISE 
THE UPPER LEVELS ARE VERY DRY N OF 18N W OF 107W AND S OF 18N W 
OF 125W.   

AN UPPER ANTICYCLONE IS CENTERED OVER OLD MEXICO AT 23N101W WITH 
A RIDGE EXTENDING SW TO A CREST NEAR 18N120W...JUST TO THE NE OF 
THE REMNANTS OF CELIA. THIS ANTICYCLONE WILL LIKELY DISSOLVE AS 
THE ANTICYCLONE ASSOCIATED WITH TROPICAL STORM ALEX IN THE BAY 
OF CAMPECHE CONTINUES TO MOVE NW ANS EXPANDS. THESE TWO UPPER 
ANTICYCLONES CURRENTLY COMBINE INTO AN IMPRESSIVE ENVELOPE OF 
UPPER ANTICYCLONIC FLOW WHICH DOMINATES THE DISCUSSION AREA FROM 
05S TO WELL N OF 32N BETWEEN 103W AND 77W. THE DEBRIS MOISTURE 
FROM THE TS ALEX CONVECTION...FROM THE CONVECTION ENHANCED ALONG 
THE REMNANT LOW PRES OF DARBY NEAR 15N98W...AND ANOTHER AREAS OF 
CONVECTION ENHANCED UNDER THIS LARGE AREA OF UPPER LEVEL 
DIFFLUENCE...IS ALL FANNING OUT MAKING THE UPPER LEVELS 
EXTREMELY MOIST UNDER THE PREVIOUSLY DESCRIBED ANTICYCLONIC 
ENVELOPE.

AT THE SURFACE...A VERY WEAK COLD FRONT EXTENDS ALONG 32N122W TO 
27N128W. A SURFACE RIDGE EXTENDS W TO E ROUGHLY ALONG 24N W OF 
115W. THE GRADIENT E OF THE WEAK FRONT CONTINUES TO PRODUCE NW 
20 KT WINDS WITHIN 300 NM OF THE SOUTHERN BAJA PENINSULA WITH 
THIS AREA EXPECTED TO SHIFT SE OVER THE NEXT FEW DAYS EVENTUALLY 
MERGING WITH THE LOW LEVEL N FLOW ASSOCIATED WITH THE REMNANT 
TROUGH OF DARBY. CROSS EQUATORIAL SOUTHERLY SWELL IS PROPAGATING 
THROUGH THE PAC WATERS S OF 12N BETWEEN 115W AND 80W. THE AREA 
AFFECTED BY THESE S SWELLS IS EXPECTED TO INCREASE TO THE ENTIRE 
AREA W OF 80W AND TO THE SE OF A LINE FROM 20N104W TO 00N137W ON 
THU.

$$
NELSON