000
AXPZ20 KNHC 111003
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT FEB 11 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...

THE MONSOON TROUGH IS UNUSUALLY WELL PRONOUNCED FOR THIS MONTH 
OF THE YEAR...AND EXTENDS FROM LOW PRES NEAR 02N78.5W 1009 MB TO 
0.5N84W TO 03.5N95W TO 09N109W TO 02N126W...WHERE IT TRANSITIONS 
TO ITCZ...CONTINUING ON TO 01N140W. SCATTERED MODERATE TO STRONG 
CONVECTION IS NOTED S OF 03N E OF 82W. SCATTERED MODERATE 
CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF TROUGH BETWEEN 91W 
AND 98W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 
120 NM N OF TROUGH BETWEEN 101W AND 107W.

...DISCUSSION...

A REINFORCING COLD FRONT HAS MOVED SE ACROSS NW PORTIONS OF THE 
AREA DURING THE PAST 24 HOURS...REACHING FROM NEAR 30N123W TO 
21N140W. A 1030 MB HIGH CENTER BEHIND THE FRONT NEAR 29N148W IS 
PRODUCING A STRONG PRES GRADIENT FROM 04N TO 21N W OF 130W AND 
ACROSS A SMALLER AREA FROM 13N TO 21N BETWEEN 119W AND 130W. NE 
WINDS 20 TO 25 KT WERE DEPICTED BY RECENT ASCAT PASSES...WHERE 
SEAS ARE CURRENTLY 9 TO 14 FT IN MIXED NW SWELL AND NE WIND 
SWELL. THESE TRADES ARE FORECAST TO SHIFT IN AREAL COVERAGE TO 
THE AREA FROM 07N TO 22N W OF 130W BY SAT EVENING...THEN FROM 
08N TO 21N W OF 130W BY SUN EVENING. FRESH NORTHERLY WINDS ARE 
ALSO OCCURRING N OF 26N WITHIN 120 NM W OF THE NORTHERN BAJA 
CALIFORNIA PENINSULA BETWEEN A SURFACE TROUGH OF LOW PRES 
LOCATED INLAND OVER WESTERN MEXICO...AND THE BUILDING HIGH PRES 
OVER THE NW PORTION OF THE AREA. THESE WINDS ARE FORECAST TO 
PERSIST THROUGH SUN EVENING.

E OF 120W...AND HIGHLY UNUSUAL PATTERN HAS DEVELOPED DURING THE 
PAST 24 HOURS...ESTABLISHING THE MONSOON TROUGH WWD TO NEAR 
126W. DURING THE PAST FEW DAYS...A WELL DEFINED MIDDLE TO UPPER 
LEVEL CYCLONE HAS MOVED ACROSS NE PORTIONS OF THE AREA...S-SE 
ALONG THE W COAST OF THE BAJA CALIFORNIA PENINSULA...AND BECOME 
CUT OFF NEAR 18N112W. THIS CYCLONE HAS COME SOMEWHAT IN PHASE 
WITH AN UPPER TROUGH EXTENDING FROM 10N110W S-SE ACROSS THE 
EQUATOR NEAR 105W. S TO SW FLOW ALOFT E OF THE CYCLONE HAS BEEN 
TRANSPORTING ABUNDANT MIDDLE TO UPPER MOISTURE ACROSS THE 
CENTRAL SWATH OF MEXICO AND INTO THE GULF OF MEXICO. A SURFACE 
TROUGH HAS DEVELOPED DURING THE PAST 24 HOURS FROM NEAR 10N109W 
TO 14N102W...WITH SCATTERED TO NUMEROUS DEEP CONVECTION 
OCCURRING ALONG AND TO THE NW OF THIS TROUGH. RECENT 
SCATTEROMETER PASSES SUGGEST NE TO E WINDS 20-25 KT TO THE N AND 
NW OF THIS TROUGH TO 20N. THIS DEEP LAYERED TROUGHING ALONG 110W 
AND HAS COMBINED WITH BROAD CLOCKWISE CIRCULATION OF WINDS 
AROUND LOW PRES ON THE S SIDE OF THE EQUATOR NEAR 05S90W TO 
RE-ESTABLISH THE MONSOON TROUGH ACROSS THE EPAC...BEING PULLED N 
TO NEAR 09N109W. THIS IS A VERY ATYPICAL ALIGNMENT AND POSITION 
OF THE MONSOON TROUGH FOR FEBRUARY. THE MIDDLE TO UPPER CYCLONE 
HAS ALREADY BEGUN TO LIFT NE...AND WILL EXIT THE AREA ACROSS NRN 
MEXICO WITHIN 24 HOURS....WHILE CONTINUING TO DRAW UPPER LEVEL 
MOISTURE ACROSS MEXICO...WITH SCATTERED BANDS OF MODERATE TO 
STRONG CONVECTION PERSISTING THE SURFACE TROUGH...BEFORE IT 
WEAKENS AFTER 24 HOURS AND DISSIPATES BY 48 HOURS. 

OTHERWISE LONG PERIOD NW SWELL YIELDING COMBINED SEAS OF 8 FT 
AND GREATER COVERS THE WATERS W OF 104W...WITH MAXIMUM 
SIGNIFICANT WAVE HEIGHTS OF 14 FEET NEAR 17N136W AS SUGGESTED BY 
RECENT ALTIMETER PASSES. THIS SWELL WILL CONTINUE TO PROPAGATE 
TO THE SE...YIELDING SEAS 8 FT AND GREATER W OF 102W BY SAT 
EVENING...AND THEN W OF 100W BY SUN EVENING WHILE MAXIMUM 
SIGNIFICANT WAVE HEIGHTS GRADUALLY SUBSIDING TO 11 FT BY THEN.

...GAP WINDS...
FRESH NORTHERLY WINDS IN THE GULF OF TEHUANTEPEC EARLY THIS 
MORNING WILL INCREASE TO GALE FORCE SAT AFTERNOON AS A COLD 
FRONT CURRENTLY MOVING THROUGH THE W GULF OF MEXICO PUSHES E OF 
THE BAY OF CAMPECHE. GALE FORCE WINDS WILL THEN CONTINUE THROUGH 
SUN AFTERNOON...AND PEAK NEAR 40 KT. 

FRESH TRADE WINDS IN THE SW CARIBBEAN WILL CONTINUE TO FUNNEL 
THROUGH THE PASSES OF CENTRAL AMERICA INTO AND DOWNWIND OF THE 
GULF OF PAPAGAYO THROUGH SUN EVENING.

$$
STRIPLING