000
AXPZ20 KNHC 182131
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON FEB 18 2008

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2130 UTC.
 
...ITCZ...
ITCZ AXIS ALONG THE LINE...2N78W 4N105W 6N140W.
SCATTERED MODERATE 60 NM EITHER SIDE OF ITCZ FROM 84W TO 93W.
SCATTERED MODERATE 45 NM EITHER SIDE OF ITCZ FROM 105W TO 124W.
SCATTERED MODERATE WITHIN 60 NM OF 7N128W.

...DISCUSSION...
UPPER LEVELS...
NARROW FRACTURED MID-UPPER LEVEL TROUGH EXTENDS FROM SRN 
CALIFORNIA SWD TO 26N128W. ANOTHER PIECE OF THE TROUGH EXTENDS 
FROM A SHEARED CYCLONIC CIRCULATION NEAR 22N132W SWWD THROUGH 
ANOTHER  DEVELOPING CIRCULATION CENTER NEAR 15N139W TO A BASE 
NEAR 7N143W. THIS TROUGH IS EXPECTED TO MOVE EWD OVER THE NEXT 
48 HOURS AND EXTEND FROM NRN BAJA CALIFORNIA TO 15N140W.  

ANOTHER WEAKER SHORTWAVE TROUGH IS SLIDING OVER THE TOP OF A 
VERY AMPLIFIED RIDGE WELL W OF THE AREA AND EXTENDS FROM 34N137W 
SWWD TO THE NW CORNER OF THE AREA. THIS TROUGH IS PROVIDING 
MINIMAL SUPPORT FOR A COLD FRONT WHICH IS JUST ENTERING THE NW 
CORNER OF THE DISCUSSION AREA. SW WINDS OF 20 TO 25 KT ARE NOTED 
ALONG THE FRONT PER THE 1408 UTC QUIKSCAT PASS. THE TROUGH WILL 
SKIRT THE N PORTION OF THE AREA IN THE WAKE OF THE PREVIOUS 
TROUGH AND AS SUCH THE CURRENT FRONTAL BOUNDARY IS FORECAST TO 
BECOME DIFFUSE WITHIN 24 HOURS. IN ANY EVENT THIS FRONT IS
EXPECTED TO USHER IN ANOTHER SWELL TRAIN WITH SEAS OF 9 TO 12 FT 
TRAVERSING THE NW PORTION OF THE MARINE AREA IN THE NEXT 24 TO 
48 HOURS. 

NARROW UPPER LEVEL RIDGE AXIS EXTENDS FROM 10N THROUGH 32N ALONG 
110W. AN AREA OF DIFLUENT UPPER LEVEL SWLY FLOW EXISTS BETWEEN 
THE RIDGE AND THE FRACTURED TROUGH GENERALLY FROM 7N TO 22N 
BETWEEN 115W AND 132W. THIS FLOW WAS ENHANCING SOME DEEP 
CONVECTION ALONG THE ITCZ BETWEEN 120W AND 130W. 

BROAD MAINLY UPPER LEVEL TROUGH N OF 20N ALONG 100W IS CONNECTED 
TO A SHEAR AXIS WHICH EXTENDS DEEP INTO THE TROPICS TO NEAR 
7N105W. STRONG UPPER LEVEL SUBSIDENCE WAS NOTED WITHIN 120-180 
NM OF THE SHEAR AXIS S OF 20N. LARGE ANTICYCLONE OVER THE S 
CARIBBEAN IS INFLUENCING THE FLOW OVER THE TROPICAL PACIFIC E OF 
100W WITH DIFLUENT UPPER LEVEL SE FLOW MAINTAINING SOME WIDELY 
SCATTERED CONVECTION ALONG THE ITCZ E OF 90W WITH A LARGE AREA 
OF MAINLY UPPER LEVEL CLOUD DEBRIS FANNING NWD ACROSS CENTRAL 
AMERICA AND THE SW CARIBBEAN.  

SURFACE...
EXCEPT FOR THE COLD FRONT ENTERING THE FAR NW CORNER OF THE 
AREA...A WEAK RIDGE WITH A 1022 MB HIGH CENTER NEAR 27N126W 
DOMINATES THE AREA N OF 10N W OF 109W. 

GAP WINDS OF 20 KT ARE FORECAST TO BEGIN IN THE GULF OF PAPAGAYO 
REGION IN THE NEXT 24 TO 30 HOURS.

$$
COBB