000
AXPZ20 KNHC 011518
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI FEB 01 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...
MONSOON TROUGH EXTENDS FROM 08N83W TO 03N90W TO 03N97. ITCZ 
CONTINUES FROM 03N97W TO 05N108W TO 08N117W 03N140W. NO 
SIGNIFICANT CONVECTION.

...DISCUSSION...
THE STRONG HIGH PRES THAT WAS AFFECTING THE FORECAST WATERS WITH 
FRESH TO STRONG TRADE WINDS THE PREVIOUS DAYS CONTINUES TO MOVES 
N AND AWAY FROM THE REGION. A WEAK 1022 MB HIGH PRES HAS NOW
DEVELOPED NEAR 29N123W AND EXTENDS A RIDGE TO NEAR 18N115W. A 
SURFACE TROUGH HAS ALSO DEVELOPED ALONG THE ITCZ AND GOES FROM 
14N118W TO 08N117W. THE PRES GRADIENT BETWEEN THE RIDGE AND THE 
TROUGH IS MAINTAINING AN AREA OF FRESH TO STRONG TRADES ROUGHLY 
FROM FROM 06N TO 15N BETWEEN 115W AND 135W. SCATTEROMETER DATA 
SHOW NE WINDS OF 25-30 KT WITHIN AROUND 120 NM W OF THE TROUGH 
AXIS. 

WINDS HAS DIMINISHED TO 20 KT ACROSS THE GULF OF CALIFORNIA AS 
HIGH PRES WEAKENS AND PRES GRADIENT RELAXES. THE MOST RECENT 
SCATTEROMETER PASSES CONFIRMED THE PRESENCE OF THESE WINDS.

A COLD FRONT WILL ENTER THE NW PORTION OF THE FORECAST REGION 
TONIGHT REACHING FROM 30N138W TO 26N140W SAT MORNING. EXPECT NLY 
WINDS OF 20-25 KT AND A NEW SET OF NW SWELL IN THE WAKE OF THE 
FRONT WHICH IS FORECAST TO DEGENERATE INTO A TROUGH FROM 30N138W 
TO 24N138W BY SAT NIGHT. THE MAJORITY OF AVAILABLE MODEL 
CONTINUES TO DEVELOP A WEAK 1010 MB LOW PRES AT THE SOUTHERN END 
OF THE TROUGH BY SAT NIGHT. IF THIS LOW DOES INDEED DEVELOP...IT 
COULD EVENTUALLY BRING A SIGNIFICANT INCREASE IN WINDS AND SEAS 
ACROSS THE NORTHERN WATERS BY SUN MORNING THROUGH EARLY NEXT 
WEEK. CURRENTLY...THE FORECAST CALLS FOR INCREASING WINDS TO 
20-30 KT AND BUILDING SEAS TO 10-13 FT ACROSS AN AREA FROM 22N 
TO 28N W OF 130W BY SUN MORNING. THESE FRESH TO STRONG WINDS 
WILL BE ASSOCIATED WITH A TIGHT PRES GRADIENT BETWEEN THE LOW 
PRES CENTER AND THE RIDGE TO THE NORTH.

GAP WINDS...
GULF OF TEHUANTEPEC...A DENSE AIR MASS BEHIND A COLD FRONT THAT 
HAS CLEARED THE ENTIRE GULF OF MEXICO CONTINUES TO BE FUNNELED 
THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. A GALE 
WARNING REMAINS IN EFFECT FOR THE GULF OF TEHUANTEPEC AND 30-40 
KT WINDS WERE CONFIRMED BY THE MOST RECENT SCATTEROMETER DATA. 
AN ALTIMETER PASS PROVIDED OBSERVATIONS OF SEA HEIGHTS UP TO 
10-11 FT NEAR 13N93W. STRONG HIGH PRESSURE BUILDING IN BEHIND 
THE FRONT OVER EASTERN MEXICO AND THE WESTERN GULF OF MEXICO 
WILL HELP TO MAINTAIN GALE FORCE CONDITIONS THROUGH TONIGHT... 
DIMINISHING BELOW GALE FORCE BY SAT MORNING.

GULF OF PAPAGAYO...EXPECT FRESH TO STRONG WINDS AND SEAS UP TO 
10 FT ACROSS THE GULF OF PAPAGAYO AND DOWNWIND OF THE GULF TO 
AROUND 91W THROUGH MON MORNING. 

GULF OF PANAMA...FRESH TO STRONG WINDS ARE BLOWING ACROSS THE 
ISTHMUS OF PANAMA FROM THE SW CARIBBEAN SEA TO THE GULF OF 
PANAMA AS MEASURED BY AN EARLIER OSCAT PASS. THESE CONDITIONS 
WILL PERSIST THROUGH SAT MORNING...DIMINISHING BY SAT EVENING. 
THESE WINDS WILL RESULT IN BUILDING SEAS TO AROUND 8 FT DOWNWIND 
OF THE GULF.

$$
GR