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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 242147
TWDEP 

TROPICAL WEATHER DISCUSSION                                   
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC THU MAY 12 2016 

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.

...TROPICAL WAVE... 

A TROPICAL WAVE WAS ANALYZED TO THE N OF 06N ALONG 78W, AND HAS
BEEN MOVING W AT ABOUT 20 KT. CURRENTLY SCATTERED MODERATE
ISOLATED STRONG CONVECTION IS OBSERVED FROM 04-08N E OF 84W
INCLUDING OVER AND ALONG THE PACIFIC COASTS OF COLOMBIA AND
PANAMA.

...INTERTROPICAL CONVERGENCE ZONE...

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N84W TO 08.5N100W TO
11N112W TO AN EMBEDDED 1011 MB SURFACE LOW PRES AT 10N124W WITH
THE MONSOON TROUGH CONTINUING SW TO 07N135W WHERE SCATTEROMETER
WINDS INDICATE AN ITCZ FORMS AND CONTINUES SW TO BEYOND 07N135W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN
90 NM EITHER SIDES OF A LINES FROM 09N90W TO 07N96W AND FROM
05N105W TO 09N107W TO 11N114W. SIMILAR CONVECTION IS NOTED WITHIN
180 NM EITHER SIDE OF LINES FROM 11N119W TO 06N136W.

THE SURFACE LOW IS FORECAST TO MOVE NW TO NEAR 11N125W ON WED
WITH THE GRADIENT SUPPORTING STRONG NE WINDS WITHIN 90 NM NW OF
THE CENTER. THE LOW IS EXPECTED TO WEAKEN TO AN OPEN TROUGH ON
THU FROM 11N127W TO 09N128W.   

...DISCUSSION...

N OF 15N E OF 120W... 

A NNW-SSE SURFACE TROUGH IS CURRENTLY ANALYZED OVER THE GULF OF
CALIFORNIA. THE TROUGH WILL MEANDER EAST AND WEST OVER THE NEXT
FEW DAYS. MODERATE SOUTHWESTERLY WINDS ARE EXPECTED N OF 25N E
OF THE TROUGH THROUGH LATE WED,THEN EXPECT THE SW FLOW TO
INCREASE BRIEFLY TO 20-25 KT ON WED NIGHT ACROSS THE GULF WATERS
FROM 29.5-31N.       

A SURFACE RIDGE EXTENDS FROM 24N120W TO 17.5N105W. THE RIDGE IS
EXPECTED TO SHIFT SLIGHTLY SW ON WED. MODERATE NW-N WINDS
CURRENTLY ACROSS THE OPEN PACIFIC WATERS N OF THE RIDGE ARE
EXPECTED TO INCREASE TO A FRESH BREEZE TONIGHT ACROSS THE WATERS
N OF 25N WITHIN 120 NM OF THE BAJA PENINSULA. THE GRADIENT WILL
CONTINUE TO TIGHTEN ON WED WITH FRESH NW-N WINDS COVERING THE
WATERS N OF 22N BETWEEN 110-120W BY EARLY THU, WITH A SMALL AREA
OF STRONG NW WINDS DEVELOPING ALONG THE PACIFIC COAST OF BAJA
NEAR 29N115W LATE THU. THE GRADIENT SHOULD BEGIN TO RELAX ON FRI.

COMBINED SEAS OF 3-6 FT ARE CURRENTLY OBSERVED BETWEEN 110-120W.
LITTLE CHANGE EXPECTED UNTIL THE WINDS INCREASE N OF THE RIDGE
WITH SEAS THEN EXPECTED TO BUILD TO NEAR 8 FT ALONG 31N ON FRI.
COMBINED SEAS OF 4-7 FT ARE EXPECTED ACROSS THE REMAINDER OF THE
OPEN PACIFIC WATERS N OF 15N E OF 110W ARE PARTIALLY DUE TO LONG-
PERIOD CROSS EQUATORIAL SOUTHERLY SWELL. 

S OF 15N E OF 110W...

MODERATE NE DRAINAGE FLOW EXPECTED ACROSS THE GULF OF PAPAGAYO
TONIGHT, THEN MOSTLY LIGHT DRAINAGE FLOW IS EXPECTED THE REST OF
THE WEEK. LIGHT DRAINAGE FLOW IS EXPECTED THIS WEEK ACROSS THE
GULF OF PANAMA.   

OTHERWISE, GENTLE NORTHERLY FLOW EXPECTED N OF THE MONSOON
TROUGH WITH COMBINED SEAS OF 4-7 FT IN MIXING CROSS EQUATORIAL
SOUTHERLY SWELL AND LONG PERIOD NW SWELL. LIGHT TO MODERATE
SOUTHERLY FLOW ACROSS THE WATERS S OF THE MONSOON TROUGH IS
EXPECTED TO INCREASE TO A FRESH BREEZE ON THU WITH SEAS BUILDING
FROM 4-7 FT TO 5-8 FT. 

ELSEWHERE FROM THE EQUATOR TO 32N E OF 140W...

A SURFACE RIDGE EXTENDS FROM 32N140W TO BEYOND 24N120W. MODERATE
TO FRESH ANTICYCLONIC FLOW IS EXPECTED ACROSS THE SUBTROPICS AND
TROPICS N OF THE MONSOON TROUGH AND ITCZ THIS WEEK. COMBINED
SEAS OF 4-7 FT ARE EXPECTED TO BUILD TO 5-8 FT ACROSS THE WATERS
FROM 30-32N ON THU NIGHT AND SPREAD S TO ALONG 28N BETWEEN 120-
130W ON FRI NIGHT. THE NE TRADES WILL BUILD SEAS OF 5-8 FT
ACROSS THE TROPICS FROM 10-15N W OF 130W ON THU NIGHT.

LONG-PERIOD SOUTHERLY SWELL IN THE FORM OF 6-8 FT SEAS WILL 
PROPAGATE ACROSS THE EQUATOR BETWEEN 114-134W ON FRI NIGHT AND
CONTINUE N TO ALONG 06N BETWEEN 111-136W ON SAT NIGHT.   

$$
NELSON