000
AXPZ20 KNHC 181533
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                          
1605 UTC SAT JAN 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1330 UTC.                              

...SPECIAL FEATURE...                                           

GULF OF TEHUANTEPEC GALE WARNING...INCREASED SURFACE PRESSURE 
OVER THE SOUTHWESTERN GULF OF MEXICO HAS TIGHTENED THE PRESSURE 
GRADIENT THROUGH CHIVELA PASS AND CONTINUES TO BRING GALE FORCE 
WINDS TO THE GULF OF TEHUANTEPEC. THERE HAVE BEEN NO MARINE 
OBSERVATIONS SINCE THE 0545 UTC OSCAT PASS WHICH SHOWED 35-40 KT 
WINDS IN THE GULF OF TEHUANTEPEC. MAXIMUM WINDS SHOULD REMAIN 
NEAR 40 KT THROUGH THE PERIOD OF PEAK DIURNAL DRAINAGE FLOW THIS 
MORNING. MINIMAL GALE CONDITIONS ARE THEN FORECAST TO PERSIST 
THROUGH 1200 UTC MON. SEAS ARE AS HIGH AS 16 FT THIS MORNING. A 
PLUME OF NE SWELL WILL CONTINUE TO PROPAGATE SW AWAY FROM THE 
GULF OF TEHUANTEPEC...MIXING WITH LONGER PERIOD NW AND SW SWELL.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 06N77W TO 05N90W. THE 
ITCZ AXIS WAS ANALYZED FROM 05N90W TO 03N101W TO 07N119W...THEN 
CONTINUES FROM 07N123W TO 06N140W. SCATTERED MODERATE CONVECTION 
WAS NOTED WITHIN 120 NM N OF THE AXIS BETWEEN 92W AND 97W AS 
WELL AS WITHIN 120 NM N OF THE AXIS BETWEEN 131W AND 138W. A 
TROUGH LIES FROM 14N120W TO 05N122W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION IS BETWEEN 180 NM AND 510 NM E OF 
THIS TROUGH AXIS.

...DISCUSSION...          

LONG-PERIOD NW SWELL HAS ENTERED THE NW PORTION OF THE AREA. 
SEAS AS HIGH AS 14 FT LIE OVER FAR NW WATERS NEAR 30N140W...WITH 
20 SECOND WAVE PERIODS ON THE LEADING EDGE OF THE SWELL 
PROPAGATING SOUTHEASTWARD TO THE NORTHERN BAJA CALIFORNIA 
PENINSULA BY THIS AFTERNOON...PASSING SOUTH OF CABO SAN LUCAS BY 
SUNRISE SUN...AND REACHING CABO CORRIENTES BY SUN EVENING. A 
SECOND BATCH OF NW SWELL WILL ENTER FAR NW WATERS SUN 
EVENING...WITH SEAS EXPECTED TO REACH 15-16 FT AND WAVE PERIODS 
IN THE 18-20 SECOND RANGE. S TO SW WINDS WILL BECOME A FRESH TO 
STRONG BREEZE OVER NW WATERS AHEAD OF A SLOW MOVING COLD FRONT 
SUN NIGHT INTO MON MORNING. THIS FRONT IS EXPECTED TO DISSIPATE 
AS IT APPROACHES THE FORECAST AREA. 

AN UPPER TROUGH ALONG 130W N OF 05N IS WEAKENING THE SUBTROPICAL 
RIDGE OVER THE FORECAST AREA. TRADE WINDS HAVE DIMINISHED TO A 
MODERATE BREEZE OR LESS. A SURFACE TROUGH ASSOCIATED WITH THE 
TROUGHING ALOFT IS FOUND FROM 14N120W TO 05N122W. CONVECTION E 
OF THE TROUGH IS NOTED IN THE SECTION ABOVE. THE UPPER TROUGH 
AND THE REAR RIGHT QUADRANT OF THE SOUTHERLY UPPER JET ON ITS 
EASTERN SIDE ARE NOT EXPECTED TO MOVE MUCH THROUGH SUN 
MORNING...ALLOWING CONTINUED ENHANCED CONVECTION HERE. THE UPPER 
TROUGH IS EXPECTED TO TURN NEGATIVE TILT AS IT PHASES WITH A 
LONG-WAVE TROUGH APPROACHING FROM THE NW LATE SUN. THIS IS 
EXPECTED TO ENHANCE THE MID-LEVEL ENERGY ON THE LEADING EDGE OF 
THE TROUGH AND ITS SURFACE REFLECTION. AN AREA OF FRESH EASTERLY 
WINDS WILL BECOME ESTABLISHED NEAR THE SURFACE TROUGH...WITH 
SEAS BUILDING TO 8-9 FT IN THIS AREA BY SUN EVENING AND QUICKLY 
MERGING WITH SEAS 8 FT OR GREATER IN NW SWELL SWEEPING SE 
THROUGH THE FORECAST AREA.

GAP WINDS...                                                    
GULF OF PAPAGAYO...THE GRADIENT BETWEEN HIGH PRESSURE FROM THE 
YUCATAN PENINSULA TO EASTERN COSTA RICA AND LOWER PRESSURE 
ASSOCIATED WITH THE MONSOON TROUGH TO THE S WILL CONTINUE TO 
ENHANCE WINDS IN THE GULF OF PAPAGAYO THROUGH MON MORNING. 
MAXIMUM WINDS TO NEAR 30 KT ARE EXPECTED IN THE PERIOD OF PEAK 
DRAINAGE FLOW BETWEEN 06Z-12Z EACH MORNING WITH SEAS TO AROUND 
10 FT.

GULF OF PANAMA...FRESH TO STRONG N WINDS WILL CONTINUE TO PULSE 
IN THE GULF OF PANAMA SOUTHWARD TO 05N IN THE MORNING HOURS OVER 
THE WEEKEND AS RIDGING EXTENDS FROM THE YUCATAN PENINSULA INTO 
EASTERN COSTA RICA. ASSOCIATED SEAS WILL BUILD UP TO 8 FT JUST 
DOWNWIND OF THE GULF OF PANAMA. THE PRESSURE GRADIENT WILL BEGIN 
TO RELAX OVERNIGHT SUN...WITH WINDS AND SEAS DROPPING BELOW 
ADVISORY CRITERIA BY SUN AFTERNOON.

$$ 
SCHAUER