000
AXPZ20 KNHC 082152
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2305 UTC TUE JAN 08 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 
2145 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS 6N77W 10N85W 3N100W 6N119W 
6N140W. SCATTERED MODERATE CLUSTERS NEAR 4N80.5W 5N88.5W AND 
WITHIN 15 NM EITHER SIDE OF THE AXIS BETWEEN 119W AND 123W AND 
BETWEEN 127W AND 132W.

...DISCUSSION...
AN UPPER LEVEL LONGWAVE TROUGH LIES N TO S ACROSS CENTRAL N 
AMERICA ALONG 107W WITH AN ASSOCIATED SHORTWAVE TROUGH EXTENDING 
INTO THE AREA ALONG 32N104W 25N107W THEN THE TROUGH CONTINUES SW 
THROUGH AN UPPER CYCLONE AT 18N128W THEN THE TROUGH CONTINUES S 
TO A BASE NEAR 7N127W. AN UPPER ANTICYCLONE CENTERED W OF AREA 
NEAR 22N150W  HAS A RIDGE AXIS EXTENDING NE TO WELL BEYOND 
32N147W WITH THE ASSOCIATED ANTICYCLONIC FLOW OVER THE UPPER 
LEVELS N OF 20N W OF 134W. UPPER MOISTURE CONTINUES TO SPILL E  
ACROSS THE UPPER LEVELS NW OF LINE 32N121W 26N138W. A BAND OF 
DRY UPPER AIR LIES ALONG THE UPPER TROUGH AXIS WITHIN 180 NM 
EITHER SIDE OF LINE 27N108W 24N122W 14N131W 17N140W.

A TROPICAL UPPER ANTICYCLONE IS QUASI STATIONARY NEAR 7N111W 
WITH A RIDGE AXIS EXTENDING N TO NEAR 16N116W. THIS RIDGE LIES 
JUST N OF THE ITCZ AND IS ENHANCING CONVECTION ALONG ITS AXIS 
BETWEEN 118W AND 131W. THE RESULTANT DEBRIS MOISTURE IS 
SPREADING N BETWEEN 111W AND 124W TO ALONG 20N WHERE THE PLUME 
TURNS NE AND NARROWS TO NEAR 25N95W.

AN UPPER ANTICYCLONE IS NEAR 5N65W WITH A RIDGE EXTENDING W 
ACROSS TROPICAL E PAC TO A CREST ALONG 2N95W 16N95W 21N84W. THE 
ASSOCIATED UPPER DIFFLUENCE IS ENHANCING ISOLATED CLUSTERS OF 
CONVECTION ALONG THE ITCZ BETWEEN 79W AND 94W WITH THE DEBRIS 
MOISTURE SPREADING N A CROSS CENTRAL AMERICA E OF 96W. OTHERWISE 
THE UPPER LEVELS ARE DRY S OF 20N E OF 108W AND SUPPRESSING 
CONVECTION ALONG THE ITCZ.

AT THE LOW LEVELS...HIGH PRES IS CENTERED NEAR 27N135W 1027 MB 
WITH A RIDGE SE TO NEAR 17N100W. TO THE S OF THIS RIDGE NE 
WINDS ARE 20 TO 25 KT WITH SEAS 9 TO 14 FT IN MIXED WIND WAVE 
AND NW SWELL. N OF THE RIDGE...NW 20 KT WINDS ARE OBSERVED NEAR 
THE SOUTHERN TIP OF THE BAJA PENINSULA. THE HIGH PRES IS 
EXPECTED TO SHIFT NE AND CONTINUE TO BLOCK THE SE ADVANCE OF THE 
NEXT SERIES OF COLD FRONTS...BUT FRESH NW SWELL IN THE 12 TO 18 
FT RANGE SHOULD ARRIVE NEAR 32N140W AROUND SUNRISE FRI.

BRISK NE TRADES IN THE W CARIBBEAN SEA ARE DIMINISHING AND THE 
NE SURGES THROUGH THE GULF OF PAPAGAYO GAP SHOULD ALSO DIMINISH 
TO LESS THAN 20 KT WED AFTERNOON.  

$$
NELSON