000
AXPZ20 KNHC 260316
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JAN 26 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0045 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH WAS ANALYZED FROM 08N78W TO 09N85W TO 05N92W. 
ITCZ WAS ANALYZED FROM 05N92W TO 05N108W TO 09N116W THEN 
CONTINUES FROM 08N121W TO 02N140W. NO SIGNIFICANT DEEP 
CONVECTION IS NOTED.

...DISCUSSION...
THE AMPLIFIED UPPER TROUGH-RIDGE-TROUGH PATTERN IN PLACE 
YESTERDAY HAS BEGUN TO FLATTEN. THE UPPER TROUGH CURRENTLY 
EXTENDS ALONG 120W N OF 10N TO A WEAKENING LOW NEAR 
32N122W...BUT ITS SURFACE REFLECTION HAS WEAKENED CONSIDERABLY 
AND WINDS HAVE DIMINISHED BELOW 25 KT NEAR THE TROUGH AS A 
RESULT. THE UPPER TROUGH IS EXPECTED TO PHASE WITH THE LEADING 
EDGE OF A DEEPENING MID-LATITUDE TROUGH THAT WILL PUSH INTO THE 
NORTHERN PORTION OF THE FORECAST AREA BY SAT. THIS MID-LATITUDE 
TROUGH IS ALREADY CARRYING A NEW TRAIN OF NW SWELL INTO NW 
WATERS...WITH PERIODS AS LONG AS 20 SECONDS. SEAS IN THE 8-10 FT 
RANGE ARE ALREADY IN PLACE AND EXPECTED THE REMAIN OVER MUCH OF 
THE AREA W OF 120W THROUGH THE FORECAST PERIOD. A PLUME OF 
TROPICAL MOSITURE LIES E OF THE UPPER TROUGH AND IS DIRECTING 
LOW TO MID LEVEL CLOUDS WITH EMBEDDED SHOWERS...AS WELL AS 
ISOLATED THUNDERSTORMS NEAR THE LOW CENTER...INTO THE BAJA 
PENINSULA AND SOUTHERN CALIFORNIA. THESE CONDITIONS ARE EXPECTED 
TO CONTINUE THROUGH THE WEEKEND. 

GAP WINDS...
GULF OF TEHUANTEPEC...THE 1546 UTC ASCAT PASS AND 1804 UTC OSCAT 
PASS CONFIRMED WINDS HAVE DIPPED BELOW GALE FORCE IN THE GULF OF 
TEHUANTEPEC AS THE DRIVING HIGH PRES IN THE NE GULF OF MEXICO 
HAS WEAKENED. ON SUN...THIS HIGH PRES SYSTEM IS EXPECTED TO 
BECOME ENGULFED IN STRONGER HIGH PRES TO ITS NE...CUTTING OFF 
THE STRONG NORTHERLY FLOW THROUGH THE ISTHMUS OF TEHUANTEPEC. 
THE 1226 UTC JASON1 PASS SHOWED SEAS AS HIGH AS 13 FT IN THE 
GULF...BUT WINDS HAVE DROPPED AROUND 10 KT SINCE THAT TIME AND 
MAXIMUM SEAS ARE BELIEVED TO HAVE CORRESPONDINGLY SUBSIDED AS A 
RESULT. HOWEVER...THE 2346 UTC JASON2 PASS SHOWS SEAS TO 8 FT AS 
FAR AS 390 NM DOWNSTREAM OF TEHUANTEPEC. SEAS IN THE GULF OF 
TEHUANTEPEC SHOULD SUBSIDE BELOW 8 FT AND WINDS BELOW 25 KT BY 
SUN AFTERNOON.

GULF OF PAPAGAYO...THE HIGH PRES OVER THE NE GULF OF MEXICO IS 
ALSO MAINTAINING MODERATE TO FRESH TRADE WINDS ACROSS THE SW 
CARIBBEAN THAT ARE FUNNELING INTO THE GULF OF PAPAGAYO. THE 1806 
UTC OSCAT PASS CONTINUES TO CONFIRM WINDS TO 25 KT DOWNWIND OF 
PAPAGAYO TO AT LEAST 89W. FRESH TO STRONG WINDS ARE EXPECTED TO 
CONTINUE HERE THROUGH THE WEEKEND WITH HIGH PRES TO THE N 
CONTINUING TO SEND EASTERLY FLOW FROM THE CARIBBEAN THROUGH 
CENTRAL AMERICA. A STRONG BREEZE WILL MOST LIKELY BE SEEN IN THE 
EARLY MORNING HOURS WHEN DRAINAGE FLOW IS AT A MAXIMUM. NE SWELL 
WILL PROPAGATE DOWNSTREAM AND KEEP SEAS AT OR ABOVE 8 FT AS FAR 
W AS 100W THROUGH SUN.

$$
SCHAUER