000
AXPZ20 KNHC 280340
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON JAN 28 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 
2000 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N85W TO 07N90W. THE 
ITCZ AXIS WAS ANALYZED FROM 07N90W TO 05N100W TO 09N126W TO 
04N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 90 NM S OF THE 
AXIS BETWEEN 118W AND 124W. 

...DISCUSSION...
A POSITIVELY TILTED UPPER-LEVEL TROUGH HAS AN AXIS THAT EXTENDS 
INTO THE FORECAST AREA FROM 32N122W TO 24N140W. THE NORTHERN 
STREAM UPPER JET ON THE LEADING EDGE OF THIS TROUGH IS EXPECTED 
TO PHASE WITH A 100 KT SOUTHERN STREAM JET MAX...CURRENTLY 
CENTERED NEAR 16N130W...ON MON. THE AMPLIFIED UPPER TROUGH WILL 
MOVE EASTWARD INTO NORTH AMERICA THROUGH TUE. A COLD FRONT 
ASSOCIATED WITH THE UPPER TROUGH WILL PUSH THROUGH NW MEXICO MON 
AND TUE. 

THE RESULTING MORE AMPLIFIED UPPER PATTERN WILL SET UP A 
STRONGER DEEP-LAYER RIDGE OVER PACIFIC FORECAST WATERS. THE 1035 
MB SUBTROPICAL HIGH ANALYZED NEAR 40N138W IS FORECAST TO 
STRENGTHEN AS IT JOGS EASTWARD OVER THE NEXT FEW DAYS. THE 1824 
UTC ASCAT PASS CAPTURED A SMALL AREA OF STRONG E-NE TRADE WINDS 
OVER W WATERS. THE AREA OF STRONG TRADES WILL EXPAND THROUGH THE 
FORECAST PERIOD. 

NW SWELL CONTINUES TO MAKE ITS WAY THROUGH THE MAJORITY OF THE 
FORECAST WATERS...WITH PERIODS AS LONG AS 18-20 SECONDS. THIS NW 
SWELL WILL MIX WITH INCREASING NE WIND-WAVES GENERATED BY THE 
STRONG TRADE WINDS. SEAS THAT ARE CURRENTLY AS HIGH AS 10 FT IN 
NW SWELL W OF 116W WILL REACH AS HIGH AS 12 FT BY TUE UNDER THE 
STRONG TRADE REGIME. 

SCATTERED SHOWERS ARE PRIMARILY FOUND E OF A SURFACE TROUGH THAT 
WAS ANALYZED FROM 12N126W TO 05N130W. THE MID-LEVEL IMPETUS FOR 
THIS TROUGH IS FORECAST TO SLOWLY MOVE WESTWARD THROUGH 
TUE...TAKING THE BEST CHANCE OF PRECIPITATION WITH IT. THE 
STRENGTHENED PRES GRADIENT BETWEEN THIS TROUGH AND RIDGING TO 
THE N IS PRODUCING FRESH NE WINDS PRIMARILY NW OF THE TROUGH 
ACCORDING TO THE 1826 UTC ASCAT PASS.

GAP WINDS...
GULF OF PAPAGAYO...STRONG HIGH PRESSURE CENTERED OVER THE MID 
ATLC UNITED STATES IS MAINTAINING MODERATE TO FRESH TRADE WINDS 
ACROSS THE SW CARIBBEAN THAT ARE FUNNELING INTO THE GULF OF 
PAPAGAYO. THE 1504 UTC ASCAT PASS CAPTURED A FRESH TO STRONG NE 
BREEZE DOWNWIND OF PAPAGAYO TO 09N90W. SHIP A8IY2 REPORTED 22 KT 
WINDS NEAR 11N89W AT 1800 UTC. FRESH TO STRONG WINDS ARE 
EXPECTED TO CONTINUE HERE THROUGH TUE 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. 

$$
SCHAUER