000
AXPZ20 KNHC 180920
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                          
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.                              

...SPECIAL FEATURE...                                           

GULF OF TEHUANTEPEC GALE WARNING...CONTINUED TIGHT SFC PRESSURE 
GRADIENT ACROSS SOUTHERN MEXICO SUPPORTS STRONG WINDS FUNNELING 
THROUGH THE CHIVELA PASS...ACCELERATING TO 30-40 KT IN THE GULF 
OF TEHUANTEPEC. 0400 UTC ASCAT AND 0545 UTC OSCAT SCATTEROMETER 
PASSES SHOWED 38-39 KT MAX WINDS NEAR 15.5N95W. EXPECT MINIMAL 
GALE CONDITIONS TO PERSIST THROUGH MON MORNING BASED ON GFS AND 
NAM MODEL FORECASTS. RESULTANT SEAS WILL BUILD TO 15-16 FT THIS 
MORNING THEN SUBSIDE SLIGHTLY TO 11-13 FT TONIGHT AND SUN. 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 EXTENDS FROM 06N77W TO 06N88W. DISCONTINUOUS 
ITCZ AXIS EXTENDS FROM 06N88W TO 04N101W TO 06N118W...THEN FROM 
08N123W TO 07N140W. NO SIGNIFICANT CONVECTION.

...DISCUSSION...          

AN UPPER TROUGH ALONG 130W N OF 05N IS WEAKENING THE SUBTROPICAL 
RIDGE ACROSS THE NORTHERN PORTION OF THE FORECAST AREA. TRADE 
WINDS REMAIN 10-15 KT OR LESS. A SURFACE TROUGH ALONG 120W FROM 
06N-14N IS COMING IN PHASE WITH THE LONG WAVE UPPER TROUGH AND 
BECOMING MORE CONVECTIVELY ACTIVE WITHIN 100-200 NM E OF THE 
TROUGH AXIS. PREVIOUS RUNS OF GFS MODEL HAVE BEEN AGGRESSIVE IN 
DEVELOPING A SHARP SURFACE TROUGH...AND FRESH TO STRONG WINDS E 
OF THE TROUGH AXIS. HOWEVER...00Z GFS MODEL SHOWS 30M WINDS 
BARELY REACHING 20-25 KT AND MAX SEAS TO 8 FT. OFFICIAL GRIDS 
REFLECT A BLEND OF PAST 2 MODEL RUNS...WHICH ARE TRENDING LOWER.

LONG PERIOD NW SWELL ASSOCIATED WITH A LOW PRES SYSTEM IN THE 
NORTH-CENTRAL PACIFIC ARE SWEEPING INTO NW PORTION OF THE AREA. 
SEAS TO 14 FT ARE EXPECTED TODAY...WITH 20 SECOND WAVE PERIODS 
ON THE LEADING EDGE OF THE SWELL. ANOTHER BATCH OF NW SWELL WILL 
ENTER THE FAR NW CORNER OF THE AREA SUN EVENING...WITH SEAS 
EXPECTED TO REACH 16-17 FT WITH WAVE PERIODS OF 18-20 SECONDS.

GAP WINDS...                                                    
GULF OF PAPAGAYO...GRADIENT BETWEEN HIGH PRESSURE NEAR CENTRAL 
AMERICA AND LOWER PRESSURE ASSOCIATED WITH THE MONSOON TROUGH 
WILL CONTINUE TO ENHANCE WINDS IN THE GULF OF PAPAGAYO THIS 
WEEKEND. MAXIMUM WINDS TO 25-30 KT ARE EXPECTED DURING PEAK 
DRAINAGE FLOW BETWEEN 06Z-12Z EACH MORNING WITH SEAS TO 9-10 FT.

GULF OF PANAMA...FRESH TO STRONG N WINDS WILL CONTINUE TO PULSE 
IN THE GULF OF PANAMA SOUTHWARD TO 05N DURING MORNING HOURS THIS 
WEEKEND AS RIDGING EXTENDS ACROSS CENTRAL AMERICA. ASSOCIATED 
SEAS WILL BUILD TO 6-7 FT DOWNWIND OF THE GULF OF PANAMA TODAY.

$$ 
MUNDELL