000
AXPZ20 KNHC 172201
TWDEP 

TROPICAL WEATHER DISCUSSION                            
NWS NATIONAL HURRICANE CENTER MIAMI FL                          
2205 UTC SAT MAY 17 2014

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 
2100 UTC. 

...SPECIAL FEATURES... 

.GULF OF TEHUANTEPEC GALE WARNING...

THE GULF OF TEHUANTEPEC GAP WIND EVENT DOES NOT WANT TO END.  
THE ASCAT SCATTEROMETER PASSES AT 15Z AND 16Z STILL SHOWED 35 KT 
N WINDS IN THE GULF.  THUS...DESPITE GUIDANCE SUGGESTING THAT 
THE EVENT SHOULD HAVE ENDED THIS MORNING...THE 18Z HIGH SEAS 
PRODUCT IS STILL INDICATING A GALE.  HOWEVER...THE FORCING FOR 
THE EVENT IS QUICKLY DIMINISHING.  THE GAP WINDS SHOULD DIMINISH 
BELOW GALE FORCE BY LATER THIS EVENING AND DROP BELOW STRONG 
BREEZE CONDITIONS BY EARLY SUNDAY MORNING. NO FURTHER 
TEHUANTEPEC GAP WINDS EVENTS ARE LIKELY IN THE NEXT SEVERAL 
DAYS. THIS LATE-SEASON GALE FORCE GAP WIND EVENT IS ONE OF THE 
LATEST GULF OF TEHUANTEPEC GALES ON RECORD.

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

THE MONSOON TROUGH EXTENDS FROM 06N77W TO 06N93W TO A 1009 MB 
LOW PRESSURE NEAR 09N107W TO 05N120W.  THE INTERTROPICAL 
CONVERGENCE ZONE IS LOCATED FROM 05N120W TO 07N131W AT A TROUGH 
THEN TO 04N140W. SCATTERED MODERATE TO STRONG CONVECTION EXISTS 
FROM 06N TO 12N BETWEEN 90W AND 113W.  SCATTERED MODERATE 
ISOLATED STRONG CONVECTION EXISTS WITHIN 120 NM SOUTH OF TROUGH 
EAST OF 88W. SCATTERED MODERATE CONVECTION EXISTS WITHIN 60 NM 
OF ITCZ BETWEEN 120W AND 125W AND BETWEEN 130W AND 135W.

...DISCUSSION...                                                 

A MODERATE 1024 MB HIGH IS CENTERED WELL NORTH OF OUR AREA WITH 
RIDGING EXTENDING SOUTHEASTWARD TO 17N106W.  THE RESULTING SMALL 
PRESSURE GRADIENT BETWEEN THE RIDGE AND THE ITCZ IS PRODUCING NE 
TRADEWINDS OF ONLY MODERATE TO FRESH BREEZE WINDS.  THIS SHOULD 
CHANGE LITTLE OVER THE NEXT SEVERAL DAYS.

A 1009 MB LOW AT 09N106W ALONG THE MONSOON TROUGH WAS SUGGESTED 
BY THE 17Z AND 18Z ASCAT SCATTEROMETER PASSES TO PERHAPS BE 
INSTEAD A SHARP WAVE.  THE DIMINISHED CONVECTION ASSOCIATED WITH 
THIS SYSTEM AND INCREASED SOUTHERLY VERTICAL SHEAR SUGGEST THAT 
THE OPPORTUNITY FOR IT TO FURTHER DEVELOP ARE LIMITED.

A TROUGH EXTENDS FROM 06N137W TO 13N130W. SCATTERED MODERATE 
CONVECTION EXISTS WITHIN 180 NM EAST OF TROUGH. WITH SIGNIFICANT 
VERTICAL SHEAR AND DRY...STABLE AIR IN THE VICINITY OF THE 
TROUGH...NO TROPICAL DEVELOPMENT OF THIS IS LIKELY.

A LONG-PERIOD SW SWELL EVENT IS INTERACTING WITH THE TEHUANTEPEC 
WIND WAVES TO PRODUCE A LARGE AREA OF 8 TO 10 FT SEAS BETWEEN 
95W AND 113W. THIS WILL GRADUALLY FADE BY LATE SUNDAY.

THE WIND GRIDS ARE A BLEND OF THE 12Z GFS...12Z ECMWF...AND THE 
PREVIOUS FORECAST.  SO WHILE THE GFS INDICATED A TROPICAL STORM 
DEVELOPMENT BY LATE NEXT WEEK FROM A NEW DISTURBANCE...THE ECMWF 
SHOWED NO SUCH GENESIS.  THE RESULTING GRIDS SHOW ONLY A WEAK 
VORTEX BY WEDNESDAY THROUGH FRIDAY.  THE WIND GRIDS ARE A BLEND 
OF THE 12Z GFS-BASED WAVEWATCH-III AND THE PREVIOUS FORECAST.  
ADDITIONALLY...THE WAVEHEIGHTS WERE CAPPED AT 10 FT WEDNESDAY 
THROUGH FRIDAY TO DOWNPLAY THE DEVELOPMENT SHOWN IN THE GFS-
BASED WAVEWATCH-III.

$$ 
LANDSEA