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Eastern Pacific Tropical Weather Discussion (Text)

000
AXPZ20 KNHC 211531
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE MAY 21 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

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

THE MONSOON TROUGH EXTENDS W FROM A LOW PRES NEAR 10N80W TO 
12N89W TO 10N96W TO 10N108W TO 08N117W TO 12N126W TO 07N135W... 
THEN TRANSITIONS TO THE ITCZ W OF 07N135W TO 05N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE 
AXIS E OF 87W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM S 
OF THE AXIS BETWEEN 96W AND 104W...AND WITHIN 75 NM OF THE AXIS 
BETWEEN 111W AND 120W.

...DISCUSSION...

A SURFACE RIDGE EXTENDS SE TO AROUND 20N110W. MODERATE TO FRESH 
NORTHERLY WINDS CONTINUE ACROSS NORTH-CENTRAL WATERS WITH SEAS 
TO 7-8 FT IN N SWELL MIXING WITH LONG PERIOD CROSS-EQUATORIAL SW 
SWELL. A REINFORCING SURGE N OF 30N LATER TODAY WILL SPREAD S 
ACROSS WATERS N OF 20N BETWEEN 115W-140W THROUGH THU NIGHT WITH 
SEAS BUILDING 8 TO 13 FT IN LONG PERIOD N SWELL WED THROUGH THU 
NEAR 30N120W. WINDS AND SEAS WILL BEGIN TO SUBSIDE ON FRI WITH 
WINDS 15 KT AND SEAS 5-7 FT ACROSS THE SUBTROPICAL WATERS BY SAT.

A TROPICAL LOW CROSSING THE ISTHMUS OF PANAMA NEAR 10N80W IS 
ASSOCIATED WITH A TROPICAL WAVE IN THE EASTERN CARIBBEAN. IT IS 
EXPECTED TO REACH THE SW CARIBBEAN WED. MODEL GUIDANCE SUGGESTS 
A SURFACE LOW WILL FORM ALONG THE MONSOON TROUGH AS THE TROPICAL 
WAVE MOVES INTO THE EASTERN PACIFIC. A SECOND WEAKER LOW IS ALSO 
EXPECTED TO DEVELOP ALONG THE MONSOON TROUGH NEAR 10N86W EARLY 
THU...WITH THE LOW MEANDERING IN THAT AREA THIS WEEKEND.

THE REMNANTS OF ALVIN CONTINUE TO WEAKEN... AND ARE DEPICTED AS 
A SW-NE ORIENTED TROUGH THAT EXTENDS FROM 09N129W TO 14N127W. 
NE TO E WINDS AT 20-25 KT AND SEAS 7-10 FT ARE NOTED WITHIN 300 
NM NW OF THE TROUGH. EXPECT THE TROUGH TO DRIFT W AND WEAKEN AS 
A BREAK IN THE CONVERGENCE ZONE. NE TRADES W OF THE TROUGH WILL 
DIMINISH TO 15-20 KT TONIGHT...WHILE SEAS SUBSIDING TO LESS THAN 
8 FT ON WED. 

GFS MODEL SHOWS NORTHERLY DRAINAGE FLOW WILL INCREASE TO 20 KT 
IN THE GULF OF TEHUANTEPEC ON FRI NIGHT THEN GRADUALLY INCREASE 
TO 20-25 KT SAT NIGHT AND SUN MORNING. 

$$
MUNDELL