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Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 060226
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC WED MAY 06 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 0215 UTC. 

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

SCATTEROMETER WINDS INDICATE THAT THE MONSOON TROUGH FORMS NEAR 
06N90W AND EXTENDS SW TO AN EMBEDDED 1009 MB LOW PRESSURE AT 
04.5N100W...AND THEN CONTINUES WNW TO 07N107W WHERE 
SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ 
EXTENDS NW TO AN EMBEDDED TROUGH AT 10N122W...THEN TURNS SW TO 
BEYOND 05N140W. THE ITCZ EMBEDDED TROUGH IS ANALYZED FROM 
07N122W TO 13N121W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED OVER AND TO THE S OF THE EASTERN PORTION OF 
THE MONSOON TROUGH...WITHIN 210 NM OF LINE FROM 02N86W TO 
07N94W. SIMILAR CONVECTION IS OBSERVED S OF THE EMBEDDED LOW 
PRESSURE...WITHIN 90 NM EITHER SIDE OF A LINE FROM 01N95W TO 
06N105W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
FLARING N OF THE ITCZ AND EXTENDS SW ALONG THE EMBEDDED TROUGH 
WITHIN 90 NM EITHER SIDE OF A LINE FROM 10N105W TO 11N112W TO 
13N126W. ISOLATED CELLS OF MODERATE CONVECTION ARE NOTED 
ELSEWHERE FROM 02S-10N BETWEEN 84-130W. 

A 1007 MB LOW PRESSURE CENTER IS ANALYZED OVER COLOMBIA NEAR 
06.5N77W WITH A TROUGH EXTENDING SW ALONG THE PACIFIC COAST OF 
COLOMBIA. SCATTERED MODERATE CONVECTION IS FLARING ALONG 
THIS TROUGH.  

...DISCUSSION... 

AN UPPER CYCLONE IS OBSERVED AT 36N122W WITH AN UPPER TROUGH  
EXTENDING SSW TO BASE AT 22N127W. AN UPPER ANTICYCLONE IS  
CENTERED NEAR 09N114W WITH AN UPPER RIDGE EXTENDING W ACROSS THE 
TROPICAL PACIFIC TO 08N138W. AN UPPER RIDGE ALSO EXTENDS E FROM 
THE ANTICYCLONE TO A FAIRLY SHARP CREST NEAR 09N89W. AN UPPER 
TROUGH EXTENDS S ACROSS THE WESTERN CARIBBEAN CROSSING PANAMA TO 
A BASE OVER THE DEEP TROPICAL PACIFIC AT 04N83W. 

UPPER MOISTURE IS ROTATING CYCLONICALLY NE AROUND THE UPPER 
CYCLONE AND ACROSS SOUTHERN CALIFORNIA AND THE NORTHERN BAJA 
CALIFORNIA PENINSULA. VERY DRY UPPER AIR IS INDICATED ELSEWHERE 
OVER THE NORTHERN PORTION OF THE DISCUSSION AREA INCLUDING 
NORTHERN MEXICO...ROUGHLY N OF A LINE FROM 28N97W TO 22N140W. 
UPPER DIFFLUENCE UNDER THE PREVIOUSLY DESCRIBED WESTERN TROPICAL 
RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AND ITS EMBEDDED 
TROUGH ALSO PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE 
IS ADVECTED NE FROM THE ITCZ BETWEEN 113W AND 120W. THIS 
MOISTURE MERGES ALONG 20N WITH A TROPICAL PLUME ORIGINATING IN 
THE CENTRAL PACIFIC THAT STREAMS ENE ACROSS THE DISCUSSION AREA 
WITHIN 150 NM EITHER SIDE OF A LINE FROM 18N140W TO ACROSS 
SOUTHERN BAJA AND CENTRAL MEXICO. WEAK UPPER DIFFLUENCE BETWEEN 
THE PREVIOUSLY MENTIONED EASTERN TROPICAL RIDGE AND AN UPPER 
TROUGH IS ENHANCING CONVECTION OVER AND TO THE S OF THE MONSOON 
TROUGH AS PREVIOUSLY DESCRIBED...WITH THE UPPER DEBRIS MOISTURE 
ADVECTED S ACROSS THE EQUATOR BETWEEN 86-113W. 

ELSEWHERE AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 32N140W 
TO 16N102W. A SURFACE TROUGH EMBEDDED IN THE ITCZ FROM  07N121W 
TO 13N120W IS FORECAST TO SHIFT W FROM 05N131W TO 14N126W ON WED 
AND FROM 04N136W TO 13N130W LATE THU. THE GRADIENT IS EXPECTED 
TO TIGHTEN SW OF THE RIDGE AXIS OVER THE NEXT FEW DAYS 
INCREASING THE NE TRADES TO 20-25 KT BETWEEN THE TROUGH AND THE 
RIDGE WITH SEAS BUILDING 7-10 FT IN THE NE WINDS WAVES THAT WILL 
MIX WITH  LONG PERIOD SW AND NW SWELL. ALTHOUGH THE TROUGH WILL 
MOVE W OF 140W ON FRI...EXPECT THE FRESH NE TRADES TO CONTINUE 
THROUGH THE UPCOMING WEEKEND ACROSS THE TROPICAL WATERS BETWEEN 
08-19W WITH EMBEDDED PATCHES OF STRONG TRADES. FRESH NW-N WINDS 
ARE EXPECTED ACROSS THE SUBTROPICAL WATERS NE OF THE RIDGE INTO 
THE UPCOMING WEEKEND. LONG PERIOD NW SWELL WILL PROPAGATE S INTO 
THE DISCUSSION AREA AND MIX WITH LONG PERIOD SOUTHERLY SWELL 
DRIVING THE COMBINED SEAS TO 7-10 FT ACROSS THE WATERS N OF 28N 
BETWEEN 116-128W THROUGH THU NIGHT...THEN GRADUALLY SUBSIDING 
THEREAFTER.

ANOTHER BATCH OF LONG PERIOD SW SWELL WILL CROSS THE EQUATOR 
BETWEEN 92-120W ON SUN NIGHT REACHING ALONG 03N ON MON.  

GULF OF CALIFORNIA...A SURFACE LOW WILL MOVE E OVER THE FAR 
NORTHERN GULF OF CALIFORNIA TONIGHT WHERE IT WILL MEANDER 
THROUGH FRI. THE GRADIENT WILL SUPPORT S-SW 20-25 KT PULSES 
WITHIN ABOUT 90 NM S OF THE CENTER. AS THE LOW MOVES E ON THU 
NIGHT THE GRADIENT WILL BRIEFLY SUPPORT NW-N 20-25 KT WINDS OVER 
THE NW QUADRANT AS WELL. THE BRIEF STRONG PULSES WITH LIMITED 
FETCH SHOULD ONLY ALLOW SEAS TO BUILD TO A MAXIMUM OF 7 FT.

$$ 
NELSON

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Page last modified: Wednesday, 06-May-2015 02:26:33 UTC