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Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 062152
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY  
THROUGH 2145 UTC. 

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

SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS NEAR 07N102W   
AND EXTENDS WNW TO EMBEDDED TROUGH AT 10N125W...THEN THE ITCZ 
CONTINUES SW TO BEYOND 03N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED E OF THE ITCZ WITHIN 120 NM EITHER 
SIDE OF A LINE FROM 03N92W TO 06.5N98W. SIMILAR CONVECTION IS 
NOTED OVER AND TO THE N OF THE ITCZ WITHIN 150 NM EITHER SIDE OF 
A LINE FROM 09.5N110W TO 11.5N124W AND ALONG THE ITCZ WITHIN 75 
NM EITHER SIDE OF A LINES FROM 11.5N124W TO 08N130W AND FROM 
04N133W TO 03N140W. CLUSTERS OF SCATTERED MODERATE ISOLATED 
STRONG CONVECTION ARE OBSERVED WELL S OF THE ITCZ WITHIN 90 NM 
EITHER SIDE OF A LINE FROM 02N107W TO 05N113W.

A 1008 MB LOW PRESSURE CENTER IS ANALYZED OVER CARIBBEAN COAST   
OF COLOMBIA AT 10N75W WITH A LOW LEVEL TROUGH EXTENDING SW ALONG 
THE PACIFIC COAST OF COLOMBIA TO A BASE OVER THE TROPICAL 
PACIFIC AT AT 03N81W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS FLARING WITHIN 120 NM OF THE TROUGH AXIS. ISOLATED 
CLUSTERS OF MODERATE CONVECTION IS NOTED ELSEWHERE FROM 03-09N 
BETWEEN 80-92W. 

...DISCUSSION...

AN UPPER TROUGH EXTENDS SW FROM SOUTHERN CALIFORNIA AT 34N120W  
TO 17N139W. AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS 
NEAR 13N110W WITH AN UPPER RIDGE EXTENDING W TO A SHARP CREST AT 
10N133W WITH SEVERAL MORE EMBEDDED SMALL ANTICYCLONIC CENTERS 
INDICATED ALONG THE RIDGE BY THE CLOUD MOTION VECTORS. AN UPPER 
RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE TO ANOTHER FAIRLY 
SHARP CREST NEAR 10N87W. A SHORTWAVE RIDGE EXTENDS N ACROSS 
CENTRAL MEXICO TO A CREST OVER SOUTHERN TEXAS. AN UPPER TROUGH 
EXTENDS S ACROSS THE WESTERN CARIBBEAN FROM CENTRAL CUBA TO 
ACROSS PANAMA TO A BASE OVER THE DEEP TROPICAL PACIFIC AT 
04N85W. 

A BAND OF UPPER MOISTURE IS MOVING ACROSS THE SHORTWAVE RIDGE 
FROM 19-26N BETWEEN FROM PACIFIC AT 111W ACROSS MEXICO AND THE 
GULF OF MEXICO ALONG 94W. THERE ARE EMBEDDED CLUSTERS OF 
CONVECTION WITHIN THIS AREA AND THESE WILL LIKELY CONTINUE INTO 
EARLY TONIGHT. VERY DRY UPPER AIR IS INDICATED ELSEWHERE OVER 
THE NORTHERN PORTION OF THE DISCUSSION AREA INCLUDING NORTHERN 
MEXICO IN NEARLY ZONAL UPPER FLOW...ALL ROUGHLY N OF A LINE FROM 
27N97W TO 10N140W. 

UPPER DIFFLUENCE AROUND THE TROPICAL UPPER ANTICYCLONE AND ITS 
WESTERN RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AND ITS 
EMBEDDED LOW LEVEL TROUGH AS PREVIOUSLY DESCRIBED. THE RESULTANT 
DEBRIS MOISTURE SEEMS TO EVAPORATE WITHIN A FEW HUNDRED MILES OF 
THE CLUSTERS. A THIN TROPICAL MOISTURE PLUME ORIGINATING IN THE 
CENTRAL PACIFIC IS STILL STREAMING ENE ACROSS THE DISCUSSION 
AREA WITHIN 120 NM EITHER SIDE OF A LINE FROM 16N140W TO JUST S 
OF THE SOUTHERN BAJA PENINSULA WHERE IT MERGES WITH THE DENSE 
PLUME ALREADY DESCRIBED. WEAK UPPER DIFFLUENCE BETWEEN THE 
PREVIOUSLY MENTIONED EASTERN TROPICAL RIDGE AND THE CARIBBEAN 
UPPER TROUGH IS ENHANCING THE CONVECTION OVER THE AREA S OF 10N 
BETWEEN 83-100W...WITH THE UPPER DEBRIS MOISTURE EVAPORATING AS 
IT SPREADS SW ACROSS THE EQUATOR BETWEEN 90-120W. 

ELSEWHERE AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 33N140W 
TO 12N91W. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 08N126W 
TO 15N124W...AND IS FORECAST TO SHIFT W FROM 05N135W TO 12N130W 
ON THU AND NEARLY FILL FROM 04N139W TO 11N138W LATE FRI. THE 
GRADIENT SW OF THE RIDGE IS SUPPORTING 20-25 KT NE TRADES ACROSS 
THE WATERS FROM 10-18N BETWEEN 120-140W. THE NE WIND WAVES ARE 
MIXING WITH LONG PERIOD SW AND NW SWELL RESULTING IN COMBINED 
SEAS OF 7-10 FT. THE GRADIENT WILL GRADUALLY RELAX THROUGH SAT 
WITH THE WINDS DIMINISHED TO 15-20 KT ON SUN...AND THE AFFECTED 
AREA OF ENHANCED SEAS OF 7-9 FT WILL SHRINK FROM 06-13N BETWEEN 
130-140W ON TUE. 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 117-130W 
THROUGH FRI EVENING...THEN GRADUALLY SUBSIDING THEREAFTER.

ANOTHER BATCH OF LONG PERIOD SW SWELL WILL CROSS THE EQUATOR E 
OF 120W ON SUN NIGHT REACHING ALONG 06N ON TUE.  

GULF OF CALIFORNIA...WEAK LOW PRESSURE IS EXPECTED TO SOON  
DEVELOP ALONG A SURFACE TOUGH OVER THE NORTHERN GULF OF 
CALIFORNIA WHERE IT WILL MEANDER THROUGH FRI...AND MOVE E OVER 
EXTREME NW MEXICO ON FRI NIGHT. THE GRADIENT WILL SUPPORT S-SW 
20-25 KT PULSES WITHIN ABOUT 90 NM S OF THE CENTER. THE LIMITED 
FETCH SHOULD ONLY ALLOW SEAS TO BUILD TO A MAXIMUM OF 7 FT. 
GUIDANCE IS SUGGESTING THE GRADIENT NE OF THE PACIFIC RIDGE WILL 
SUPPORT NW WINDS OF 20-25 KT ALONG THE PACIFIC COAST OF THE BAJA 
PENINSULA ON FRI NIGHT THROUGH SAT NIGHT.

GULF OF PAPAGAYO...EXTENDED GUIDANCE INDICATES NE-E 20-25 KT 
WINDS OVER AND SW OF THE GULF OF PAPAGAYO ON MON NIGHT.

$$ 
NELSON

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Page last modified: Wednesday, 06-May-2015 21:52:38 UTC