000
AXPZ20 KNHC 141517
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON DEC 14 2009

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.

...ITCZ...
AXIS EXTENDS FROM 07N78W TO 07N98W TO 05N105W TO 08N120W TO 
06N130W TO 08N140W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION WITHIN 120 NM S OF AXIS W OF 138W.

...DISCUSSION...
A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE NORTHERN BAJA 
PENINSULA SW TO NEAR 15N130W. AN UPPER LEVEL RIDGE EXTENDS FROM 
50N135W TO 35N135W TO E OF HAWAII NEAR 25N145W. AT THE 
SURFACE...A 1021 MB HIGH PRES AREA IS CENTERED NEAR 30N127W. A 
WEAK TROUGH IS NOTED ALONG THE ITCZ ALONG 120W PER ASCAT DATA 
FROM AROUND 06Z AND ANIMATED SATELLITE IMAGERY. ASCAT...WINDSAT 
AND SHIP OBSERVATIONS INDICATE A BROAD AREA OF FRESH TO STRONG 
TRADE WINDS ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH  
PRES...MAINLY FROM 07N TO 15N W OF 115W. SHIP OBSERVATIONS ALSO 
INDICATE 20 KT WINDS BETWEEN THE HIGH PRES AND THE BAJA COAST. 
THE MID TO UPPER LEVEL TROUGH WILL DIG INTO NORTH CENTRAL MEXICO 
AS THE RIDGE SHIFTS EAST AND BUILDS OVER NORTHERN BAJA...AHEAD 
OF A BROAD UPPER TROUGH DIGGING OVER THE N CENTRAL PACIFIC. THE 
SURFACE HIGH PRES WILL STRENGTHEN AS THE UPPER RIDGE BUILDS 
ACROSS THE REGION...MAINTAINING THE FRESH TO STRONG TRADES 
THROUGH MIDWEEK EVEN THROUGH THE SURFACE TROUGH ALONG THE ITCZ 
WILL LIKELY WEAKEN AND SHIFT WEST. A COLD FRONT WILL APPROACH 
THE DISCUSSION AREA FROM THE NW TONIGHT...BUT STALL

MEANWHILE 8 TO 10 FT NW SWELL WITH PERIODS TO 11 SECOND IS 
MOVING INTO THE WATERS N OF 20N. ANOTHER SET OF NW SWELL WILL 
MOVE INTO THE DISCUSSION AREA TONIGHT...COVERING AN AREA NW OF A 
LINE FROM 30N130W TO 25N140W BY MIDDAY TUE.

SURFACE HIGH PRES WILL ALSO BUILD OVER THE GREAT BASIN AS THE 
UPPER RIDGE MOVES INTO THE ROCKIES...CAUSING WINDS TO INCREASE 
THROUGH THE GULF OF CALIFORNIA STARTING TONIGHT. WINDS TO NEAR 
GALE FORCE ARE POSSIBLE OVER THE NORTHERN PORTIONS OF THE GULF 
OF CALIFORNIA BY TUESDAY. 

SHIP OBSERVATIONS FROM THIS MORNING...AND HIGH RESOLUTION ASCAT 
DATA FROM LAST EVENING...SHOW FRESH TO STRONG GAP WIND FLOW 
PERSISTING THROUGH THE GULF OF TEHUANTEPEC. LAND-BASED STATIONS 
AND BUOYS IN THE GULF OF MEXICO SHOW GRADIENT FLOW IS ACTUALLY 
FAIRLY LIGHT OVER THE SW GULF OF MEXICO AND ISTHMUS OF 
TEHUANTEPEC THIS MORNING. THE TEHUANTEPEC WINDS ARE LIKELY THE 
RESULT OF DRAINAGE FLOW DUE TO COOL AND DRY CONDITIONS OVER THE 
LAND. THIS IS ALSO THE CONTRIBUTING TO FRESH TO STRONG THROUGH 
THE GULF OF PAPAGAYO FURTHER SOUTH...WHERE MORNING DRAINAGE FLOW 
OVER THE MOUNTAINS OF COSTA RICA IS PUSHING FRESH TRADE WINDS 
OFF THE CARIBBEAN INTO THE GULF OF PAPAGAYO. THESE WINDS WILL 
PERSIST THROUGH MIDWEEK...WHILE WINDS THROUGH TEHUANTEPEC ARE 
EXPECTED TO DIMINISH LATER TODAY. THIS WILL BE SHORT LIVED 
HOWEVER...AS A COLD FRONT PUSHES INTO THE SW GULF WED...BRINGING 
A NEW ROUND OF STRONG GAP WINDS TO TEHUANTEPEC WED INTO THU.
  
$$
CHRISTENSEN