000
AXPZ20 KNHC 270943
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 27 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 07N78W TO 04N90W. ITCZ EXTENDS FROM 
04N90W TO 04N105W TO 06N110W TO 04N125W TO 05N140W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 45 NM EITHER SIDE OF A LINE 
FROM 12N105W TO 09N115W.

...DISCUSSION...

BROAD MID TO UPPER LEVEL TROUGH EXTENDS ALONG 105W FROM NW 
MEXICO TO 05N. TRADE WIND CONVERGENCE NEAR THE ITCZ ALONG WITH  
DIVERGENCE ALOFT ASSOCIATED WITH THE UPPER TROUGH ARE TOGETHER 
ENHANCING A LINE OF SCATTERED MODERATE CONVECTION WITHIN 45 NM 
EITHER SIDE OF A LINE FROM 12N105W TO 09N115W. A 0524 UTC ASCAT 
PASS INDICATED AN ASSOCIATED SURFACE TROUGH ALONG 113W. SINCE 
THIS FEATURE HAS MIGRATING W OF THE UPPER TROUGH INTO THE 
SUBSIDENT AREA OF A SHORT WAVE RIDGE...THE TROUGH AND ASSOCIATED 
CONVECTION WILL LIKELY DIMINISH THROUGH OVER THE NEXT 24 HOURS. 

W OF THE UPPER RIDGE...A QUASISTAIONARY UPPER LOW IS CENTERED 
NEAR 15N140W. SENSORS PICKED SOME LIGHTNING STRIKES IN THE AREA 
JUST TO THE SE OF THE UPPER LOW N OF THE ITCZ TO 12N BETWEEN 
125W AND 130W...BUT THIS HAS SINCE DIMINISHED. 

FURTHER NORTH...STRONG SURFACE PRES CENTERED OFF THE OREGON 
COAST IS MAINTAINING 20 KT NE TO E WINDS OVER THE WATERS N OF 
24N W OF 125W...AS NOTED IN EARLIER SHIP AND SCATTEROMETER DATA. 
THE WINDS WILL DIMINISH THROUGH LATE SAT AS THE SURFACE HIGH 
PRES WEAKENS AND SHIFT FURTHER S. MEANWHILE...NW SWELL CONTINUES 
TO PUSH INTO THE AREA AND WILL ENCOMPASS MUCH OF THE AREA N OF 
05N W OF 110W BY LATE SAT...MIXING WITH NE SWELL ASSOCIATED WITH 
TRADE WINDS GENERALLY FROM 05N TO 10N W OF 120W. 

GULF OF CALIFORNIA...A SHORT WAVE TROUGH WILL EMERGE OUT OF THE 
NW FLOW ALOFT AND PUSH SE ACROSS THE GULF OF CALIFORNIA STARTING 
EARLY SAT...BEFORE DEAMPLIFYING AND LIFT NE SUN. NW SURFACE 
WINDS INCREASE ACCORDINGLY DOWN THE LENGTH OF THE GULF 
SAT...REACHING 20 TO 25 KT BY LATE SAT BEFORE DIMINISHING BELOW 
20 KT BY LATE SUN AS THE SUPPORTING UPPER TROUGH LIFTS OUT.

GULF OF TEHUANTEPEC...1020 MB SURFACE HIGH PRES IS BUILDING OVER 
NE MEXICO BEHIND A WEAK COLD FRONT MOVING THROUGH THE CENTRAL 
GULF OF MEXICO. THE COLD AIRMASS BEHIND THE FRONT IS FAIRLY 
MILD...AND THE SURFACE HIGH PRES REMAINS. A 0552 UTC OSCAT PASS 
SHOWED WINDS TO 25 KT IN THE GULF OF TEHUANTEPEC. HIGHER WINDS 
MAY STILL OCCUR LATER IN THE MORNING DUE TO DRAINAGE 
EFFECTS...BUT THE DURATION OF THE GALE WARNING IN EFFECT FOR 
TEHUANTEPEC HAS BEEN SHORTENED SLIGHTLY TO 18 UTC TO ACCOUNT FOR 
WEAKENING TREND IN THE PATTERN. LOOKING AHEAD...A REINFORCING 
FRONT FOLLOWED BY A STRONGER HIGH PRES WILL ENTER THE GULF OF 
MEXICO LATE SAT INTO SUN. EXPECT WINDS TO SURGE TO GALE FORCE 
THROUGH THE GULF OF TEHUANTEPEC BY EARLY SUN.

GULF OF PAPAGAYO...20 TO 25 KT GRADIENT FLOW OVER THE SW 
CARIBBEAN ALONG WITH OVERNIGHT DRAINAGE EFFECTS WILL SUPPORT 20 
KT GAP WINDS THROUGH THE GULF OF PAPAGAYO REACHING AS FAR AS 
88W...MAINLY DURING THE OVERNIGHT HOUR AND EARLY MORNING HOURS.

$$
CHRISTENSEN