000
AXPZ20 KNHC 271510
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON SEP 27 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...

SATELLITE IMAGERY SHOWS VERY SPARSE CONVECTION ASSOCIATED WITH 
PERSISTENT QUASI-STATIONARY 1006 MB LOW PRES CENTERED NEAR 
16N108W. EAST SHEAR CONTINUES TO ACT ON THIS THE LOW 
PRES...KEEPING THE FEW SHOWERS AND THUNDERSTORMS WELL TO THE 
WEST OF THE CENTER. THE SHEAR IS EXPECTED TO DIMINISH OVER THE 
NEXT DAY OR SO AS AN UPPER LEVEL ANTICYCLONE BRINGS WEAKER AND 
MORE DIFFLUENT FLOW OVER THE SYSTEM. THIS MAY ALLOW THE 
CONVECTION TO CONSOLIDATE BETTER NEAR THE CENTER OF THE LOW PRES 
AND POSSIBLY ALLOW IT TO DEVELOP INTO A TROPICAL CYCLONE OVER 
THE NEXT DAY OR SO. PLEASE REFER TO THE LATEST TROPICAL WEATHER 
OUTLOOK FROM THE NATIONAL HURRICANE CENTER FOR MORE DETAILS.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 10N112W TO 
12N125W TO 11N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 90 
NM S OF THE ITCZ AXIS FROM 116W TO 113W.

...DISCUSSION...

AN UPPER LEVEL RIDGE LIES BETWEEN AN ANTICYCLONE NEAR 20N102W 
AND ANOTHER ANTICYCLONE NEAR 30N127W. AN UPPER LOW OVER THE 
CENTRAL GULF OF CALIFORNIA NEAR 28N111W LIES TO THE N OF THE 
TROUGH AXIS. THIS LOW IS SIPHONING DEEP LAYER TROPICAL MOISTURE 
NORTHWARD OVER THE SURFACE LOW MENTIONED IN THE SPECIAL FEATURES 
SECTION ABOVE AND INTO THE GULF OF CALIFORNIA. WITH MOSITURE NOT 
A LIMITING FACTOR...CONVECTION ASSOCIATED WITH THIS SURFACE LOW 
MAY INCREASE AS THE EASTERN ANTICYCLONE SHIFTS SW OVER THIS 
SURFACE LOW AND CONSOLIDATES WITH THE WESTERN ANTICYCLONE ALOFT 
WHICH IS EXPECTED TO BE FORCED SOUTHWARD BY THE WESTWARD 
MIGRATING UPPER LOW PASSING OVER THE CENTRAL BAJA PENINSULA. 
THIS WILL MAKE FOR A MORE DIFFLUENT PATTERN ALOFT OVER THE 
SURFACE LOW AND POSSIBLY ALLOW FOR SOME DEVELOPMENT OF THE LOW.

THE BUOY DATA AND THE ASCAT PASS FROM AROUND 0318 UTC SHOW SW 
WINDS OFF THE COAST OF CENTRAL AMERICA TO 20 KT WHILE SHIP ZCDF4 
TRAVELING S APPROXIMATELY 100 NM OFF THE COAST OF EL SALVADOR 
REPORTED STRONGER SW WINDS AND SEAS TO 9 FT BETWEEN 1000 UTC AND 
1300 UTC THIS MORNING. MEANWHILE...SW WINDS HAVE DIMINISHED IN 
THE GULF OF TEHUANTEPEC IN RESPONSE TO THE DISSIPATING REMNANTS 
OF MATTHEW OVER SOUTHERN MEXICO ACCORDING TO THE ASCAT PASS. THE 
FORECAST FOR THIS AREA IS HIGHLY DEPENDENT ON THE PATTERN OVER 
THE NORTHWESTERN CARIBBEAN AND SOUTHEASTERN GULF OF MEXICO OVER 
THE NEXT FEW DAYS. THE CURRENT FORECAST CALLS FOR THE 
DEVELOPMENT OF A SURFACE LOW OVER THE NW CARIBBEAN THAT WILL 
LIFT NE AHEAD OF A COLD FRONT STRADDLING THE GULF FROM NE TO SW. 
NORTHERLY WIND BEHIND THE COLD FRONT IS EXPECTED TO SIPHON 
THROUGH THE ISTHMUS OF TEHUANTEPEC ON TUE AND SHIFT THE SURFACE 
WINDS MORE NORTHERLY THERE WHILE THE DOMINANT FLOW S OF 14N AND 
E OF ABOUT 100W REMAINS SOUTHWESTERLY.

AN INCREASE IN POOLED MOISTURE ALONG THE ITCZ AND DIFFLUENT FLOW 
ALOFT OVER THE ITCZ BETWEEN THE AFOREMENTIONED RIDGE AXIS TO THE 
NE AND AN UPPER LOW CENTERED NEAR 02N128W HAS ALLOWED FOR AN 
INCREASE IN CONVECTION ALONG THE ITCZ W OF 115W. 

FURTHER TO THE N...15-17 SECOND PERIOD SWELL HAS PUSHED SE FROM 
THE N CENTRAL PACIFIC INTO THE FORECAST AREA FROM THE BORDER OF 
CALIFORNIA AND MEXICO TO THE WEST-CENTRAL PORTION OF THE 
FORECAST AREA. SEAS ARE CURRENTLY AS HIGH AS 13 FT OVER NW 
WATERS WITH THIS SWELL TRAIN ACCORDING TO THE JASON2 PASS FROM 
AROUND 0800 UTC. THE FORECAST CALLS FOR THIS INITIAL SWELL TRAIN 
TO CONTINUE TO SPREAD SE THROUGH THE AREA AND GRADUALLY 
SUBSIDE...WITH THE LEADING EDGE OF THIS SWELL REACHING FROM CABO 
CORRIENTES TO THE EQUATOR NEAR 125W WED MORNING. A SECOND SURGE 
OF NW SWELL WILL REACH NW WATERS TUE AND BRING THE SEAS BACK TO 
THE 10 TO 13 FT RANGE TUE AFTERNOON AND EVENING OVER NW WATERS.

$$
SCHAUER