000
AXPZ20 KNHC 090912
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON NOV 09 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC.

...TROPICAL LOWS...

1009 MB LOW PRES IS EMBEDDED IN THE ITCZ NEAR 08N102W. THE 
CONVECTION PREVIOUSLY ASSOCIATED WITH THIS SYSTEM HAS BEEN 
SHEARED TO THE SOUTH BY A 20 KT NORTHERLY UPPER JET. THERE IS NO 
SIGNIFICANT CONVECTION CURRENTLY NOTED NEAR THE LOW.

1008 MB LOW PRES IS EMBEDDED IN THE ITCZ NEAR 11N112W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND WITHIN 210 
NM OF THE LOW CENTER EXCEPT TO 300 NM IN THE NW QUADRANT. THIS 
SURFACE LOW CURRENTLY LIES UNDER A REGION OF WEAK...DIFFLUENT 
UPPER LEVEL FLOW. THE SOUTHWESTERLY JET ON THE EASTERN SIDE OF 
THE UPPER TROUGH TO THE WEST OF THIS LOW IS EXPECTED TO SHEAR 
THE SYSTEM BY LATE TUE AND INHIBIT ANY FURTHER DEVELOPMENT.

1008 MB LOW PRES IS EMBEDDED IN THE ITCZ NEAR 10N122W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION LIES WITHIN 240 NM E 
AND SW QUADRANTS OF THE LOW. THIS PERSISTENT SURFACE LOW IS 
UNDER INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH THE JET ON 
THE LEADING EDGE OF THE UPPER TROUGH CENTERED FROM 20N125W TO 
10N140W. THIS TROUGH IS EXPECTED TO SLOWLY SHIFT NW OVER THE 
NEXT TWO DAYS...PRIMARILY PASSING N OF THE LOW. BRIEF 
ENHANCEMENT OF THE CONVECTION ASSOCIATED WITH THE LOW IS 
POSSIBLE AS THE UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE REAR 
RIGHT QUADRANT OF THE JET APPROACHES IT OVERNIGHT TONIGHT. THE 
LOW WILL THEN MOVE UNDER INCREASING NORTHERLY UPPER FLOW THAT 
SHOULD DISSIPATE THE SYSTEM.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 07N77W TO 08N85W TO 08N105W TO 
11N115W TO 08N140W. OUTSIDE OF THE TROPICAL LOWS EMBEDDED IN THE 
ITCZ MENTIONED ABOVE...SCATTERED MODERATE CONVECTION CAN BE 
FOUND WITHIN 90 NM S OF AXIS BETWEEN 126W AND 130W...IN THE 
VICINITY OF THE REAR RIGHT QUADRANT OF THE AFOREMENTIONED UPPER 
JET.

...DISCUSSION...

A HIGH PRES RIDGE STEMMING FROM A 1022 MB HIGH NEAR 33N133W WITH 
A RIDGE EXTENDING SE TO NEAR 17N110W DOMINATES NORTH WATERS AT 
THE SURFACE. THIS HIGH PRES SYSTEM IS PART OF A LARGER NORTH 
PACIFIC RIDGE THAT IS CURRENTLY BEING COMPROMISED BY A COLD 
FRONT JUST NORTH OF THE FORECAST AREA. WHILE THIS FRONT IS 
EXPECTED TO DISSIPATE AS IT REACHES FORECAST WATERS TUE...LONG 
PERIOD NW SWELL FROM THE SYSTEM HAS ALREADY PUSHED WELL INTO 
WATERS N OF 06N W OF 110W WITH THE HIGHEST SIGNIFICANT WAVE 
HEIGHTS...15 TO 17 FT...FOUND N OF THE RIDGE AXIS. THIS SWELL 
WILL CONTINUE TO SPREAD S THROUGH THE FORECAST AREA W OF 100W 
OVER THE NEXT FEW DAYS...WITH MAXIMUM WAVE HEIGHTS OVER N WATERS 
SUBSIDING TO THE 10 TO 14 FT RANGE BY EVENING. THE SE 
PROGRESSION OF THE COLD FRONT N OF FORECAST WATERS WILL FORCE 
THE HIGH CENTER SE INTO N WATERS TODAY. EASTERLY TRADE WINDS 
WILL PERSIST THROUGH THE FORECAST PERIOD ON THE S SIDE OF THE 
RIDGE AXIS. QUIKSCAT PASSES FROM 0156 AND 0338 UTC SHOW A BROAD 
AREA OF NE WINDS IN THE 15 TO 25 KT RANGE W OF 110W AND S OF THE 
RIDGE.

GAP WINDS...
THE 0016 UTC QUIKSCAT PASS SHOWED LIGHT AND VARIABLE WINDS IN 
THE GULF OF TEHUANTEPEC. HOWEVER...NORTH WINDS ARE EXPECTED TO 
ONCE AGAIN FUNNEL THROUGH THE ISTHMUS OF TEHUANTEPEC THIS 
AFTERNOON AS A COLD FRONT PASSES SOUTH THROUGH THE WESTERN GULF 
OF MEXICO ON THE WESTERN SIDE OF HURRICANE IDA. WINDS IN THE 
GULF OF TEHUANTEPEC ARE EXPECTED TO INCREASE TO GALE FORCE BY 
SUNRISE TOMORROW AND PERSIST THROUGH THE FORECAST PERIOD. IT 
SHOULD BE NOTED THAT THERE IS CONSIDERABLE UNCERTAINTY IN THE 
TIMING AND STRENGTH OF THE GAP WINDS IN THE GULF OF TEHUANTEPEC 
DUE TO THE UNCERTAINTY IN THE TRACK AND INTENSITY OF IDA. FOR 
NOW...WINDS ARE FORECAST TO REACH 40 KT BY THE END OF THE 
FORECAST PERIOD WED MORNING.

$$
SCHAUER