000
AXPZ20 KNHC 190951
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JUN 19 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 FEATURES...
A BROAD AREA OF LOW PRESSURE CONTINUES OVER THE PACIFIC WATERS S 
OF MEXICO...AND IS CURRENTLY ANALYZED AS AN 1006 MB SURFACE LOW 
NEAR 13N99W. NUMEROUS STRONG CONVECTION NOTED WITHIN 120 NM W 
AND WITHIN 30 NM E SEMICIRCLES OF CENTER. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED ELSEWHERE WITHIN THE 360 NM 
OVER THE N SEMICIRCLE OF CENTER. MODEL GUIDANCE SUGGESTS GRADUAL 
DEVELOPMENT OF THIS SURFACE LOW OVER THE NEXT SEVERAL DAYS AS IT 
DRIFTS WEST...WITH TROPICAL CYCLONE FORMATION LIKELY. SOUTHERLY 
WINDS WILL INCREASE TO THE S OF THIS SURFACE LOW TO THE EQUATOR 
OVER THE NEXT FEW DAYS.   
  
...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 09N83W TO THE LOW PRES AT 
13N98W...THEN CONTINUES SW TO 08N129W WHERE LOW LEVEL WINDS 
INDICATE THE ITCZ BEGINS AND CONTINUES W TO BEYOND 05N140W. 
LOCALLY BROKEN LOW AND MID LEVEL CLOUDS ARE NOTED OVER THE 
ENTIRE AREA N OF THE EQUATOR TO THE E OF 90W...AND FROM 05N TO 
THE MEXICAN COAST BETWEEN 90W AND 102W...AND FROM 07N TO 10N 
BETWEEN 102W AND 123W. ISOLATED EMBEDDED CLUSTERS OF MODERATE 
AND STRONG CONVECTION ARE NOTED WITHIN 240 NM EITHER SIDE OF A 
LINE FROM 06N79W TO 09N117W. ISOLATED MODERATE TO STRONG 
CONVECTION CONTINUES TO FLARE WITHIN 60 NM OF MEXICAN COAST FROM 
85W TO 102W...WITH THE STRONGEST ACTIVITY CURRENTLY IN AND JUST 
TO THE S OF THE GULF OF TEHUANTEPEC. 

...DISCUSSION...
AN UPPER TROUGH EXTENDS SW FROM SOUTHERN CALIFORNIA TO 29N120W 
THEN INTO AN UPPER CYCLONE AT 22N139W...WITH THE UPPER TROUGH 
THEN CONTINUING SW TO BASE OVER THE TROPICS AT 11N142W. A 
SECONDARY REINFORCING UPPER TROUGH HAS REACHED ALONG 32N BETWEEN 
112W AND 122W. UPPER MOISTURE IS NOTED OVER THE NW SEMICIRCLE OF 
THE UPPER CYCLONE. UPPER MOISTURE ORIGINATING FROM YESTERDAYS 
ITCZ CONVECTION NEAR 06N138W IS NOW SPREADING NE WITHIN 120 NM 
EITHER SIDE OF A LINE FROM 12N137W TO 24N130W...BUT SEEMS TO BE 
EVAPORATING. VERY DRY UPPER AIR IS INDICATED WITHIN 240 NM SE OF 
INITIAL TROUGH AXIS...AND OVER THE REMAINDER OF THE DISCUSSION 
AREA TO THE N OF 10N AND TO THE W OF 122W. 

A SMALL UPPER CYCLONE IS NOTED OVER THE DEEP TROPICS NEAR 
02N132W. AN UPPER ANTICYCLONE IS QUASI STATIONARY OVER CENTRAL 
OLD MEXICO AT 26N105W WITH ITS ENVELOPE OF ANTICYCLONIC FLOW 
DOMINATING MOST THE DISCUSSION AREA BETWEEN 98W AND 122W...WITH 
AN UPPER RIDGE EXTENDING SW TO A FAIRLY SHARP CREST AT 10N134W. 
AN UPPER TROUGH EXTENDS SW ACROSS THE SE GULF OF MEXICO INTO A 
SMALL UPPER CYCLONE OVER THE BAY OF CAMPECHE. AN UPPER LEVEL 
ANTICYLONE IS OVER THE W CARIBBEAN AT 14N81W. BROAD RIDGING... 
AND UPPER DIFFLUENCE CONTINUES OVER THE TROPICAL PACIFIC E OF 
ABOUT 110W. ENHANCED CONVECTION HAS RESULTED IN DEEP LAYERED 
MOISTURE...WITH CONVECTION IS LIKELY TO CONTINUE TO FLARE IN THE 
AREA S OF 18N E OF 102W FOR THE NEXT DAY OR SO.

ELSEWHERE AT THE LOW LEVELS...A BROAD RIDGE COVERS THE AREA N OF 
THE 10N TO THE W OF 118W. THE GRADIENT NE OF THE RIDGE WILL 
MAINTAIN NORTHWESTERLY LOW LEVEL FLOW AT 15 TO 20 KT ALONG THE 
PACIFIC SIDE OF THE BAJA CALIFORNIA PENINSULA TODAY AND TONIGHT 
THEN THE GRADIENT WILL RELAX SOME. NE FLOW WILL CONTINUE TODAY 
INTO TONIGHT AT 15 TO 20 KT SW OF THE RIDGE IN THE AREA N OF 26N 
W OF 133W. THE GRADIENT WILL INCREASE AGAIN ON TUE AS A DRY 
NORTHERLY SURGE DIPS S OVER THE MARINE AREA TO THE N OF 27N 
BETWEEN 120W AND 130W...ACCOMPANIED BY A NORTHERLY SWELLS 
RESULTING IN COMBINED SEAS TO 8 FT.   

$$
NELSON