000
AXPZ20 KNHC 182149
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT DEC 18 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.

...TROPICAL LOWS...

A WELL DEFINED SURFACE LOW PRES CENTERED NEAR AT 10N112W WITH AN 
ESTIMATED CENTRAL PRESSURE OF 1010 MB. A 1738 UTC ASCAT PASS
CAPTURED NE WINDS OF 15 TO LOCALLY 20 KT IN THE NW QUADRANT OF 
THE LOW BUT FAILED TO CAPTURE THE STRONGER WINDS OVER THE 
EASTERN SEMICIRCLE OF THE LOW. THE LOW IS EXPECTED TO MOVE 
WESTWARD AT 10 KT OVER THE NEXT 48 HOURS TO NEAR 10N114W 
IN 24 HOURS AND NEAR 10N117W BY 48 HOURS WITH LITTLE CHANGE IN 
WINDS AND SEAS.  

ANOTHER PERSISTENT SURFACE LOW PRES IS CENTERED NEAR 07N87W WITH 
AN ESTIMATED CENTRAL PRESSURE OF 1010 MB. A 1200 UTC WINDSAT 
PASS CAPTURED SOUTHWESTERLY WINDS OF 15 TO 20 KT WITHIN ABOUT 
180 NM OVER THE SE QUADRANT WITH SEAS TO 8 FT. THE LOW IS 
EXPECTED TO MEANDER IN THE SAME AREA THROUGH 48 HOURS WITH 
LITTLE CHANGE IN WIND AN SEAS.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N77W TO LOW 
PRES NEAR 07N87W TO LOW PRES NEAR 10N112W TO 07N126W TO 12N140W. 
SCATTERED MODERATE ISOLATED STRONG N OF 02N E OF 83W. SCATTERED 
MODERATE WITHIN 120 NM OF 10N110W. SCATTERED MODERATE ISOLATED 
STRONG FROM 06N TO 11N W OF 138W.

...DISCUSSION...

SURFACE HIGH PRESSURE 1020 MB IS CENTERED NEAR 24N123W WITH 
RIDGE EXTENDING WEST TO BEYOND 23N140W AND SE TO 18N110W. A 
SURFACE COLD FRONT EXTENDS FROM 30N132W TO 28N140W WITH SW WINDS 
OF 20 TO 25 KT NOTED WITHIN 300 NM E OF THE FRONT AND SEAS TO 11 
FT IN NW SWELL WEST OF THE FRONT. SEVERAL SECONDARY SURGES WILL 
PUSH THE NORTHERN SEGMENT OF THE FRONT E TO THE NORTHERN BAJA 
CALIFORNIA PENINSULA AROUND THE MIDDLE OF NEXT WEEK FOLLOWED BY 
SEAS TO 14 FT IN NW SWELL.  

A LOW LEVEL TROUGH EXTENDS FROM 17N138W TO 08N140W WITH ACTIVE 
CONVECTION AND NE TRADES TO 20 KT WITHIN 240 NM E OF TROUGH
FROM 14N TO 18N. EXPECT THE TROUGH TO CONTINUE MOVING W AND BE W 
OF 140W WITHIN 24 TO 36 HOURS. 
 
GAP WINDS...A WEAK COLD FRONT WILL MOVE SE THROUGH THE WESTERN 
GULF OF MEXICO TONIGHT WITH 20 TO 25 KT NORTHERLY WINDS SURGING 
THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC LATE 
TONIGHT. GUIDANCE NOW SUGGESTS SOUTHERLY RETURN FLOW WILL 
QUICKLY BECOME ESTABLISHED OVER THE GULF OF MEXICO ON SUN 
DIMINISHING THE THE N WINDS IN THE GULF OF TEHUANTEPEC TO LESS 
THAN 20 KT BY LATE SUN.  

$$
COBB