000
AXPZ20 KNHC 282138
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 03N77W TO 07N86W TO 
07N90W. ITCZ AXIS WAS ANALYZED FROM 07N90W TO 07N125W TO 08N132W 
TO 05N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 210 NM N OF 
THE AXIS BETWEEN 124W AND 130W.

...DISCUSSION...
A POSITIVELY TILTED UPPER-LEVEL TROUGH AXIS EXTENDS THROUGH 
TIJUANA MEXICO TO 28N120W TO 24N137W. A BROAD SOUTHWESTERLY 
UPPER JET LIES E OF THIS AXIS AND IS DIRECTING TROPICAL MOSITURE 
FROM THE ITCZ NEAR 130W THROUGH THE SOUTHERN BAJA CALIFORNIA 
PENINSULA INTO NW MEXICO. SCATTERED MODERATE CONVECTION WAS 
NOTED IN THE REAR RIGHT QUADRANT OF THIS UPPER JET WITHIN 210 NM 
N OF THE ITCZ AXIS BETWEEN 124W AND 130W. A COLD FRONT 
ASSOCIATED WITH THIS UPPER TROUGH WAS ANALYZED FROM NEAR TUCSON 
ARIZONA TO THE CENTRAL BAJA CALIFORNIA PENINSULA. THIS FRONT 
WILL CONTINUE EASTWARD THROUGH NORTHERN MEXICO THROUGH TUE. 

A STRONG DEEP-LAYER RIDGE HAS SET UP BEHIND THE TROUGH OVER AND 
N OF PACIFIC FORECAST WATERS. THE 1036 MB SUBTROPICAL HIGH 
ANALYZED NEAR 38N135W EXTENDS A RIDGE AXIS SOUTHEASTWARD THROUGH 
32N1134W TO 20N110W. THE PRES GRADIENT BETWEEN THIS RIDGE AND 
THE FRONT OVER NW MEXICO IS FORCING A STRONG NW BREEZE ALONG THE 
BAJA CALIFORNIA NORTE COAST N OF 29N AS SEEN BY SHIP 3FYB3 WHO 
REPORTED 26 KT NW WINDS AND 8 FT SEAS NEAR 29N117W AT 1900 UTC. 
THESE WINDS ARE FORECAST TO DIMINISH TUE AS THE FRONT MOVES 
EASTWARD. THE UPPER TROUGH IS EXPECTED TO SHED SOME ENERGY THAT 
WILL LINGER OFF THE SOUTHERN CALIFORNIA COAST...WEAKENING THE 
SURFACE RIDGING IN THAT AREA AND SHIFTING THE RIDGE AXIS TO THE 
SW. THIS SHOULD TIGHTEN THE PRESSURE GRADIENT BETWEEN RIDGE AND 
THE ITCZ BY WED...ALLOWING FOR TRADES NEAR GALE FORCE JUST N OF 
THE ITCZ AXIS. CURRENTLY...STRONG NE-E TRADES LIE OVER MUCH OF 
THE AREA FROM 10N-26N W OF 124W. 

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 WED UNDER THE 
STRONG TO NEAR GALE TRADE REGIME. 

GAP WINDS...
GULF OF PAPAGAYO...STRONG ATLANTIC HIGH PRESSURE CENTERED OVER 
OFF THE CAROLINA COAST IS MAINTAINING MODERATE TO FRESH TRADE 
WINDS ACROSS THE SW CARIBBEAN THAT ARE FUNNELING INTO THE GULF 
OF PAPAGAYO. SHIP A8UL4 REPORTED 21 KT NE WINDS AND 7 FT SEAS 
NEAR 10N89W AT 1500 UTC...AFTER THE EARLY MORNING DIURNAL 
MAXIMUM IN DRAINAGE FLOW OFF THE LAND. STRONG NE WINDS SEEN 
PRIMARILY IN THOSE EARLY MORNING HOURS ARE EXPECTED TO DIMINISH 
ON WED...LEAVING SOME NE SWELL TO 8 FT TO LINGER INTO THE 
AFTERNOON.  

$$
SCHAUER