000
AXPZ20 KNHC 092200
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC FRI JAN 09 2015

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 PRESSURE GRADIENT BETWEEN 
STRONG RIDGING EXTENDING S FROM THE NE COAST OF MEXICO TOWARD 
THE ISTHMUS OF TEHUANTEPEC AND TROUGHING TO THE S ALONG THE ITCZ 
IS STILL SUPPORTING 35 KT GALE FORCE WINDS IN THE GULF OF 
TEHUANTEPEC DURING THE OVERNIGHT AND EARLY MORNING HOURS. 
SCATTEROMETER DATA FROM THIS MORNING CONFIRMED THE PRESENCE OF 
THESE WINDS. THE RIDGE IS FORECAST TO WEAKEN...BUT MINIMAL GALE 
FORCE WINDS WILL CONTINUE TO PULSE ACROSS THE GULF OF 
TEHUANTEPEC TONIGHT INTO SAT MORNING...THEN AGAIN SAT NIGHT INTO 
SUN MORNING. SEAS ARE EXPECTED TO GRADUALLY SUBSIDE TO 9-12 FT 
TONIGHT...AND TO 8-11 FT SAT NIGHT. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
             
THE MONSOON TROUGH EXTENDS FROM THE COAST OF COLOMBIA NEAR 
03N77W TO 02N80W TO 05N88W. THE ITCZ AXIS CONTINUES FROM 05N88W 
TO 03N100W TO 04N110W TO 06N125W TO 07N140W. SCATTERED MODERATE 
CONVECTION IS NOTED WITHIN 60 NM N OF ITCZ AXIS BETWEEN 93W AND 
95W...AND BETWEEN 133W AND 135W. 
 
...DISCUSSION...                                                 

A COLD FRONT EXTENDS FROM 30N124W TO 22N131W THEN CONTINUES AS A 
STATIONARY FRONT TO 20N138W. A 1024 MB HIGH PRES LOCATED NW OF 
THE AREA IS IN THE WAKE OF THE FRONT. ANOTHER WEAK HIGH PRES 
DOMINATES THE NE PART OF THE FORECAST REGION. THE COLD FRONT 
WILL GRADUALLY WEAKEN AS IT CONTINUES TO MOVES EASTWARD. THE 
MAIN IMPACT OF THE FRONT IS NW SWELL...WITH PERIODS IN THE 19-20 
SECOND RANGE CURRENTLY ALONG THE COAST OF BAJA CALIFORNIA. THE 
NW SWELL PROPAGATING S OF 20N WILL MEET UP WITH AN AREA OF FRESH 
TO OCCASIONALLY STRONG TRADE WINDS W OF 120W THIS EVENING... 
PRODUCING SEAS IN THE 8-12 FT RANGE. THE TRADES OVER W WATERS 
WILL BE DRIVEN BY THE PRESSURE GRADIENT BETWEEN THE ITCZ AND 
STRONGER HIGH PRES BEHIND THE COLD FRONT. 

FRESH TO LOCALLY STRONG N WINDS ARE FUNNELING INTO THE GULF OF 
PANAMA FROM THE CARIBBEAN. WINDS WILL PULSE TO 25 KT DURING THE 
LATE NIGHT AND EARLY MORNING HOURS THROUGH SAT MORNING AND 
DIMINISH TO 20 KT OR LESS DURING THE AFTERNOON AND EARLY EVENING 
HOURS. 

MINIMAL GALE CONDITIONS WERE IN PLACE ACROSS THE GULF OF 
PAPAGAYO THIS MORNING. WEAKENING OF THE RIDGE ACROSS MEXICO AND 
THE GULF OF MEXICO THIS AFTERNOON WILL ACT TO DIMINISH THE 
PRESSURE GRADIENT IN THE AREA...THUS THE WINDS IN THE GULF OF 
PAPAGAYO. WINDS WILL PULSE TO 30 KT SAT MORNING AND TO 25 KT SUN 
MORNING AS THE PRESSURE GRADIENT CONTINUES TO WEAKEN.

NE SWELL FROM BOTH THE GULFS OF PAPAGAYO AND TEHUANTEPEC HAVE 
BROUGHT SEAS IN THE 8-12 FOOT RANGE TO MUCH OF THE DOWNSTREAM 
AREA E OF 120W. THIS AREA OF SEAS PRIMARILY ATTRIBUTED TO NE 
SWELL WILL SHRINK EASTWARD AS THE WINDS IN THE GAPS GENERALLY 
DIMINISH AND NW SWELL MOVES INTO WESTERN WATERS.

$$ 
GR