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Eastern Pacific Tropical Discussion

Active Tropical Systems Basin Outlooks Satellite
Eastern Pacific Basin Tropical Discussion
 
543 
AXPZ20 KNHC 010230
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC WED JUL 01 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC. 
 
...TROPICAL WAVES...

TROPICAL WAVE ALONG 90W/91W FROM 05N TO 12N. SCATTERED MODERATE  
CONVECTION IS NOTED FROM 06N TO 08N BETWEEN 86W AND 90W. 
POSITION IS BASED ON CONTINUITY AS THE TROPICAL WAVE IS POORLY 
REPRESENTED IN LATEST DATA AND SATELLITE IMAGERY.

TROPICAL WAVE ALONG 100W/101W FROM 09N TO 15N SHOWS UP 
RELATIVELY WELL IN THE LOWER TO MID LEVELS OF THE ATMOSPHERE 
BASED ON GOES HIGH DENSITY WINDS AND ANIMATED PRECIPITABLE WATER 
IMAGERY. IT ALSO HAS A REASONABLE PRESENTATION IN GOES IMAGERY 
AND THE POSITION MATCHES CONTINUITY. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS NOTED E OF THE WAVE AXIS FROM 09N 
TO 14N BETWEEN 95W AND 100W. THESE SHOWERS AND THUNDERSTORMS ARE 
ENHANCED TO A LARGE DEGREE BY A NEGATIVELY TILTED UPPER TROUGH 
POSITIONED TO THE NW OF THE TROPICAL WAVE.

TROPICAL WAVE ALONG 125W/126W FROM 07N TO 14N. THE WAVE IS 
POSITIONED TO THE SOUTH OF A LARGE UPPER LOW. DRY SUBSIDENT FLOW 
ON THE WESTERN SIDE OF THE UPPER LOW IS SUPPRESSING CONVECTIVE 
DEVELOPMENT N OF THE WAVE. CONVERSELY DIVERGENCE ALOFT SOUTH OF 
THE UPPER LOW ALONG WITH WEAK TRADE WIND CONVERGENCE IN THE 
LOWER LEVELS IS ENHANCING AREAS OF CONVECTION SEVERAL HUNDRED 
MILES TO THE EAST AND WEST OF THE TROPICAL WAVE. WHILE THE WAVE 
REMAINS INDISTINCT WHILE EMBEDDED IN THIS AREA OF 
CONVECTION...IT PRESUMED TO HAVE A FAIRLY LOW AMPLITUDE SOUTH OF 
THE SUBTROPICAL RIDGE.

TROPICAL WAVE ALONG 135W/136W FROM 07N TO 15N. THE WAVE SHOWS UP 
WEAKLY ON GOES DERIVED HIGH DENSITY WINDS AND IN VISIBLE 
IMAGERY. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE. 
EARLIER SCATTEROMETER DATA INDICATED THERE IS SOME ENHANCEMENT 
TO TRADE WIND FLOW NW OF THE WAVE BETWEEN THE WAVE AND THE 
SUBTROPICAL RIDGE TO THE NORTH.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

NO MONSOONAL CIRCULATION IS EVIDENT ACROSS THE REGION. THE ITCZ 
EXTENDS FROM 09N102W TO 07N105W TO 10N115W TO BEYOND 06N140W. 
SCATTERED MODERATE CONVECTION NOTED WITHIN 180 NM EITHER SIDE OF 
AXIS BETWEEN 115W AND 135W.

...DISCUSSION...

N OF 15N E OF 120W...A MID LATITUDE UPPER LEVEL BLOCKING PATTERN 
CONTINUES TO SPAN THE WESTERN STATES AND THE ADJACENT OCEANIC 
AREAS TODAY. TO THE SOUTH OF THIS RIDGE...A LARGE MIDDLE/UPPER 
LEVEL CYCLONIC CIRCULATION CENTERED NEAR 22N120W WITH A SHARP 
NEGATIVELY TILTED TROUGH REACHING TOWARD 19N105W. A FEW SHOWERS 
AND THUNDERSTORMS WERE NOTED MOVING ACROSS NW MEXICO AND THE 
CENTRAL GULF OF CALIFORNIA IN THE DIVERGENT FLOW ALOFT BETWEEN 
THESE FEATURES...BUT THIS HAS DIMINISHED OVER THE GULF. A WEAK 
SUBTROPICAL RIDGE TO THE WEST IS MAINTAINING FAIRLY LIGHT 
SURFACE WINDS ACROSS THE REGION. SUCCESSIVE ALTIMETER PASSES 
FROM THE MORNING INDICATED ONLY 3 TO 5 FT SEAS IN MOST AREAS. NO 
CHANGES ARE EXPECTED THROUGH THU IN THE PATTERN. LOOKING AHEAD 
TO LATE IN THE WEEK...WINDS WILL INCREASE SLIGHTLY OFF THE COAST 
OF BAJA CALIFORNIA NORTE AND NORTHERN PORTIONS OF BAJA 
CALIFORNIA SUR BETWEEN THE RIDGE TO THE WEST AND LOWER PRES OVER 
NW MEXICO.

S OF 15N E OF 110W...STRONG TRADE WIND FLOW THROUGH THE SW 
CARIBBEAN IS PUSHING INTO THE EASTERN PACIFIC THROUGH THE GULF 
OF PAPAGAYO AND OTHER LOCATIONS ALONG THE COAST OF NICARAGUA TO 
THE GULF OF FONSECA. OVERNIGHT ASCAT DATA INDICATED 20 TO 25 KT 
THIS MORNING...AND THIS WILL PERSIST THROUGH THE NEXT 24 TO 36 
HOURS WITH SEAS BUILDING AS HIGH AS 11 FT. FRESH NORTHERLY GAP 
WINDS WERE ALSO NOTED INTO THE GULF OF PANAMA. CONVECTION 
ADJACENT TO A PAIR OF WEAK TROPICAL WAVES NEAR 89W AND 100W IS 
RELATED IN PART TO AN UPPER TROUGH NORTH OF THE AREA. OTHERWISE 
FAIRLY LIGHT AND DISORGANIZED FLOW IN THE DEEP TROPICS IS NOTED 
IN TOGA BUOY OBSERVATIONS AND EARLIER ASCAT DATA. THE WINDS AND 
SEAS ARE EXPECTED TO DIMINISH TO 20 KT OR LESS AND LESS THAN 8 
FT THROUGH 36 HOURS. ALTIMETER DATA IS INDICATING GENERALLY 4 TO 
5 FT SEAS OUTSIDE OF AREA OF GAP WIND INFLUENCE.

ELSEWHERE...THE SUBTROPICAL RIDGE N OF 20N IS MAINTAINING 
GENERALLY MODERATE TRADE WIND FLOW INTO THE DEEP 
TROPICS...EXCEPT FOR NEAR THE TROPICAL WAVE AT 135W...WHERE 
SATELLITE DERIVED DATA INDICATES FRESH TRADES AND SEAS TO 8 FT 
FROM 11N TO 15N W OF 133W. ASIDE FROM THE CONVECTION NOTED ALONG 
THE ITCZ...SUBSIDENT FLOW ON THE WEST SIDE OF THE UPPER LOW IS 
INHIBITING CONVECTIVE DEVELOPMENT. NO MAJOR CHANGES EXPECTED 
THROUGH THE NEXT 48 HOURS AT THE SURFACE. LOOKING AHEAD...GLOBAL 
MODELS INDICATE FAVORABLE FLOW ALOFT ALLOWING WEAK LOW PRES 
FORMING IN THE DEEP TROPICS BETWEEN 135W AND 140W BY THIS 
WEEKEND. 
 
$$ 
CHRISTENSEN