000
AXPZ20 KNHC 230954
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JUN 23 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.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS W FROM COSTA RICA AT 10N85W TO 10N92W 
THEN TURNS NW PARALLEL TO CENTRAL AMERICA TO NEAR 17N100W. THE 
MONSOON TROUGH RESUMES NEAR 17N110W AND EXTENDS SW THROUGH 
10N119W TO 07N124W WHERE LOW LEVEL WINDS INDICATE THAT THE ITCZ 
BEGINS...AND EXTENDS W TO BEYOND 06N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 120 NM EITHER SIDE 
OF A LINE FROM 06N78W TO 08N83W TO 06N94W TO 10N102W AND ANOTHER 
LINE FROM 12N111W TO 08N110W. LOCALLY BROKEN LOW AND MID LEVEL 
CLOUDS... WITH EMBEDDED SHOWERS ARE OBSERVED S OF 07N E OF 
97W...AND ELSEWHERE WITHIN 240 NM S OF THE WESTERN SEGMENT OF 
THE MONSOON TROF AXIS. THE MONSOON TROUGH IS EXPECTED TO AMPLIFY 
N TO THE COAST OF OLD MEXICO AT 100W IN ABOUT 24 HOURS...AND 
FURTHER AMPLIFY N TO OVER OLD MEXICO NEAR 20N100W AND ALSO SHIFT 
NE OVER INTERIOR CENTRAL AMERICA BY LATE SAT. A TROPICAL WAVE 
OVER THE W CARIBBEAN IS EXPECTED TO MOVE NW OVER PORTIONS OF 
CENTRAL AMERICA THIS WEEKEND...BUT SHOULD LOSE IDENTITY IN THE 
STRONG SOUTHWESTERLY LOW LEVEL FLOW OVER THE PACIFIC WATER ALONG 
CENTRAL AMERICA.    

...DISCUSSION...
AN UPPER TROUGH IS APPROACHING THE NW PORTION WITH SOUTHERLY 
UPPER FLOW OBSERVED TO THE N OF 18N W OF 132W. AN UPPER LEVEL 
ANTICYCLONE IS CENTERED AT 30N117W...WITH A RIDGE EXTENDING SW 
TO 16N140W...AND A RIDGE ALSO EXTENDS SE TO A SHARP CREST OVER 
THE SOUTHERN TIP OF BAJA CALIFORNIA. AN UPPER CYCLONE IS 
CENTERED OVER THE SW TEXAS AT 31N101W...WITH AN UPPER TROUGH 
EXTENDING SW ALONG 18N110W TO 15N115W. THIS TROUGH SEPARATES THE 
ANTICYCLONIC FLOW OVER NW OLD MEXICO FROM THE UPPER DIFFLUENT 
FLOW ASSOCIATED WITH A SECOND UPPER ANTICYCLONE CENTERED AT 
23N100W. THIS UPPER DIFFLUENCE ENHANCED VIGOROUS CONVECTION OVER 
CENTRAL MEXICO FOR THE SECOND DAY...WITH THE DEBRIS MOISTURE NOW 
COVERING MOST OF WESTERN GULF OF MEXICO. 

UPPER DIFFLUENCE HAS SHIFTED SLIGHTLY TO SE OF WESTERN SEGMENT 
OF THE MONSOON TROUGH. CONVECTION FLARED EARLIER BUT HAS 
DIMINISHED TO A SMALL LINE FROM 12N111W TO 08N110W. THE 
RESULTANT DEBRIS MOISTURE IS ADVECTED SW IN STRONG UPPER NE FLOW 
ACROSS THE DISCUSSION AREA...WITHIN 420 NM EITHER SIDE OF A LINE 
FROM 17N100W TO 02N126W. A COUPLE OF SMALL UPPER CYCLONES ARE 
EMBEDDED IN THE UPPER LEVEL EASTERLY FLOW OVER THE TROPICS S OF 
THE SUBTROPICAL RIDGE...ONE NEAR 14N134W AND ANOTHER NEAR 
02N138W. THE UPPER LEVELS APPEAR VERY DRY TO THE NW OF A LINE 
FROM THE SOUTHERN BAJA CALIFORNIA PENINSULA TO 10N130W...AND 
OVER THE DEEP TROPICS TO THE S OF 10N W OF 130W...AND 
SUPPRESSING CONVECTION ALONG THAT SEGMENT OF THE ITCZ. THIS DRY 
UPPER AIR EXTENDS N ACROSS MOST IF THE SW CONUS WITH LITTLE 
CHANCE OF UPPER DEBRIS MOISTURE FOR AT LEAST ANOTHER DAY. 

AN UPPER TROUGH EXTENDS SW ACROSS THE NW CARIBBEAN TO A SHARP 
BASE OVER BELIZE. AN UPPER ANTICYCLONE IS OVER THE SW CARIBBEAN 
WITH A RIDGE EXTENDING NW TO OVER HONDURAS. CONVECTION HAS 
FLARED UNDER THIS RIDGE AND ALONG THE MONSOON TROUGH THAT LIES 
PARALLEL TO CENTRAL AMERICA. THE DEBRIS MOISTURE SPREADS W OVER 
THE TROPICS TO THE N OF 05N MERGING WITH THE PREVIOUSLY 
DESCRIBED MOISTURE BAND NEAR 100W.   

ELSEWHERE AT THE LOW LEVELS...A BROAD RIDGE COVERS THE AREA N OF 
10N AND W OF 120W. A DRY NORTHERLY SURGE AT 20 KT HAS DIPPED 
INTO THE MARINE AREA NE OF THE RIDGE...GENERALLY TO THE N OF 28N 
BETWEEN 127W AND 135W...AND IS ACCOMPANIED BY NORTHERLY SWELLS 
RESULTING IN COMBINED SEAS OF 8 FT. THESE NE WINDS WILL SPREAD 
SW OVER THE NW PORTION OVER THE NEXT COUPLE OF DAYS.

LOW LEVEL SW WINDS CONTINUE AT 15 TO 20 KT OVER THE AREA S OF 
05N BETWEEN 85W AND 95W...WITH THE AFFECTED AREA SHIFTING NE 
OVER THE NEXT COUPLE OF DAYS. MIXED SOUTHERLY SWELLS ARE 
CONTRIBUTING TO 8 FT SEAS IN THE WATERS S OF 18N E OF 110W...AND 
OVER THE DEEP TROPICS TO THE S OF 05N BETWEEN 110W AND 130W. THE 
NORTHERN EXTENSION OF THESE 8 FT SEAS TO SHRINK TO THE WATERS S 
OF 10N BETWEEN 85W AND 125W BY SAT.

$$
NELSON