000
AXPZ20 KNHC 100335
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI NOV 09 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS SW FROM THE COAST OF COSTA RICA AT 
09N84W TO 06N89W TO 07N103W TO 10N112W WHERE LOW LEVEL WINDS 
INDICATE A TRANSITION TO AN ITCZ...WHICH CONTINUES SW TO BEYOND 
08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 60 NM EITHER SIDE OF LINES FROM 06.5N77.5W TO 04N81W TO 
07N82W AND FROM 06N88.5W TO 10N96W TO 08N104W TO 08N113W...AND 
FROM 05N118W TO 08N127W TO 07N133W. SCATTERED MODERATE 
CONVECTION IS DISSIPATING WITHIN 120 NM OF 13N115.5W.

...DISCUSSION...

A LONGWAVE UPPER TROUGH OVER WESTERN N AMERICA CONTINUES S INTO 
THE DISCUSSION AREA FROM 32N118W TO 18N118W. A REINFORCING 
SHORTWAVE TROUGH IS MOVING THROUGH THE LONGWAVE PATTERN FROM 
32N120W TO 27N130W CONTINUING SW INTO AN UPPER CYCLONE AT 
23N143W. THIS PATTERNS SETS UP A SOUTHWESTERLY UPPER JET ACROSS 
THE DISCUSSION AREA WITHIN ABOUT 360 NM EITHER SIDE OF A LINE 
FROM 16N140W TO 30N110W WITH A SECOND UPPER WESTERLY JET 
ROTATING THROUGH THE UPPER TROUGH AXIS ACROSS THE AREA N OF 28N 
BETWEEN 127W-113W MERGING WITH THE SW JET. THESE UPPER WINDS ARE 
ADVECTING UPPER MOISTURE E OVER THE DISCUSSION AREA FROM 10N-24N 
BETWEEN 142W-119W. WEAK UPPER DIFFLUENCE IS INDICATED OVER THE 
DEEP TROPICS S OF 12N W OF 118W AND IS ENHANCING THE CONVECTION 
ALONG THE MONSOON TROUGH AND ITCZ W OF 118W WITH THE DEBRIS 
MOISTURE ADVECTED SE ACROSS THE EQUATOR BETWEEN 115W-135W. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 05N86W WITH AN UPPER 
RIDGE EXTENDING N ACROSS CENTRAL AMERICA AND THE WESTERN GULF OF 
MEXICO...AND CONTINUING N ACROSS CENTRAL N AMERICA. UPPER 
DIFFLUENCE ALONG THE W PERIPHERY OF THE ANTICYCLONE ENHANCED 
CONVECTION EARLIER...WITH DEBRIS MOISTURE NOW ORGANIZED INTO A 
500 NM WIDE TROPICAL PLUME FROM 12N113W TO 22N107W THEN TURNING 
NE AROUND THE UPPER RIDGE ACROSS N-CENTRAL OLD MEXICO.

THE REINFORCED UPPER TROUGH WILL PROGRESS E ACROSS THE WESTERN 
CONUS THROUGH THE WEEKEND MAINTAINING THE UPPER WESTERLY FLOW 
ACROSS THE DISCUSSION AREA GENERALLY TO THE N OF 11N. THE UPPER 
CYCLONE AT 23N143W WILL CUT OFF AND GRADUALLY FILL THROUGH SUN 
NIGHT. AN INVERTED UPPER TROUGH CURRENTLY DEVELOPING OVER THE 
DEEP TROPICS S OF 08N ALONG 108W WILL SHIFT WESTWARD AND DEEPEN 
INTO AN UPPER CYCLONE AT 02N112W BY LATE SAT NIGHT. THIS UPPER 
TROUGH/CYCLONE WILL EFFECTIVELY SEPARATE THE UPPER FLOW OVER THE 
SOUTHERN PORTION OF THE DISCUSSION AREA THROUGH MOST OF THE 
WEEKEND. AS THE UPPER TROUGH SHIFTS EASTWARD IT WILL DRAG A WEAK 
SURFACE COLD FRONT ACROSS THE NE WATERS TONIGHT THROUGH SAT 
NIGHT ACCOMPANIED BY SW-W-NW 10-15 KT WIND SHIFT. STRONG HIGH 
PRESSURE WILL BUILD S ACROSS THE N-CENTRAL WATERS IN THE WAKE OF 
INCREASING THE WINDS AROUND THE RIDGE TO MOSTLY 15-20 KT BUT 
INCREASING TO 20-25 KT IN THE AREA FROM 10-15N BETWEEN 120-130W 
SUN AFTERNOON. THIS INCREASING PRESSURE GRADIENT WILL ARRIVE THE 
W COAST OF THE NORTHERN BAJA PENINSULA IN THE FORM OF NW 15-20 
KT WINDS THIS EVENING...WITH SEAS OF 6-8 FT IN NW SWELL ARRIVING 
ON SAT. THESE CONDITIONS WILL SPREAD S ALONG THE ENTIRE W COAST 
OF BAJA ON SUN. EXPECT A SW-W WIND SHIFT ALONG THE WEAK COLD 
FRONT OVER THE GULF OF CALIFORNIA TO THE N OF 29N ON TONIGHT AND 
EARLY SAT MORNING WITH NW WINDS BEHIND THE FRONT BUILDING TO 
15-25 KT ACROSS THE ENTIRE GULF OF CALIFORNIA SUN NIGHT THROUGH 
MON NIGHT.    

GAP WINDS...NORTHERLY WINDS AT 20-30 KT...SEAS 8-12 FT...IN AND 
JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC WILL GRADUALLY 
DIMINISH/SUBSIDE THIS WEEKEND WITH THE NORTHERLY SWELLS MIXING 
WITH CROSS EQUATORIAL SW SWELL ACROSS THE TROPICS FROM ABOUT 
05N-14N BETWEEN 94W-112W THIS WEEKEND. EXPECT THE NE 20-25 KT 
WINDS TO CONTINUE TO SURGE THROUGH A GAP IN THE CORDILLERA INTO 
AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH SUN 
AFTERNOON. THE RESULTANT NE SWELL WILL PROPAGATE W TO ALONG 
94W...MERGING WITH THE SWELL ORIGINATING FROM THE NORTHERLY 
WINDS SURGING THROUGH THE GULF OF TEHUANTEPEC. NLY WINDS WILL 
AGAIN SURGE INTO THE GULF OF TEHUANTEPEC LATE MON AND RAPIDLY 
INCREASE TO GALE FORCE MON EVENING. THIS WILL BE A LONG TERM 
EVENT LASTING THROUGH NEXT FRI MORNING.

$$
NELSON