000
AXPZ20 KNHC 200931
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN APR 20 2008

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 
0900 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG AXIS 07N77W TO 04N84W TO 04N103W TO 
06N112W TO 03N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION WITHIN 240 NM N OF AXIS BETWEEN 112W AND 116W. 

SCATTERED MODERATE CONVECTION ALSO WITHIN 30 NM OF COLOMBIAN 
COAST S OF 5N. SCATTERED MODERATE CONVECTION FROM 7N TO 9N 
BETWEEN 95W AND 100W. SCATTERED MODERATE CONVECTION FROM 7N TO 
9N BETWEEN 125W AND 127W.

...DISCUSSION...

E OF 110W...A 01Z HIGH RESOLUTION QUIKSCAT PASS SHOWED 25 TO 30 
KT NORTH FLOW THROUGH THE GULF OF TEHUANTEPEC. THE 30 KT IS 
SOMEWHAT SUSPECT SINCE THE DATA WERE ON THE EDGE OF THE 
SWATH...BUT 25 KT FLOW IS PLAUSIBLE. THESE WINDS ARE DUE TO 
STRONG NLY FORCING THROUGH THE BAY OF CAMPECHE TO THE 
NORTH...AND SHOULD ABATE THROUGH MIDDAY TODAY. FURTHER S...A 
2330Z QUIKSCAT PASS SHOWS 20 KT ONGOING THROUGH THE GULF OF 
PAPAGAYO...IN RESPONSE TO STRONG TRADE WINDS OVER THE CARIBBEAN. 
THIS WILL LIKELY PERSIST OFF AN ON THROUGH 48 HOURS. ALOFT...A 
MID/UPPER RIDGE CONTINUES IN PLACE OVER SOUTHERN MEXICO. RELATED 
SUBSIDENCE IS KEEPING MUCH OF THE CENTRAL AMERICAN AND MEXICAN 
COAST ALMOST CLOUD FREE FROM NICARAGUA TO MAZATLAN. AN UPPER 
TROUGH ORIENTED E-W EXTENDS FROM 80W TO 110W SOUTH OF THE MID TO 
UPPER RIDGE. DIVERGENCE ALOFT BETWEEN THE TROUGH AND RIDGE IS 
ENHANCING CONVECTION OFF THE COLOMBIAN COAST AND ALONG AND NEAR 
THE ITCZ AS NOTED ABOVE. GFS AND EURO GLOBAL MODELS SHOW THE 
UPPER CYCLONIC TURNING PERSISTING THROUGH MONDAY...AND THE GFS  
HINTS OF UPPER DIVERGENCE TO THE EAST SUPPORTING AT LEAST MODEST 
CONVECTION ALONG THE ITCZ BETWEEN 90W AND 100W THROUGH 48 HOURS.

W OF 110W...A MID LEVEL SHORT WAVE TROUGH N OF 24N ALONG ROUGHLY 
120W IS PUSHING WESTWARD TOWARD THE NORTHERN BAJA COAST...AWAY 
FROM A STATIONARY CUT OFF LOW NEAR 23N142W...NE OF HAWAII BROAD 
AN UPPER RIDGE TO THE NORTH OF THE CUT OFF LOW IS FLATTENING OUT 
AND SHIFTING SE AHEAD OF A DEEP TROUGH DIGGING TO THE NORTH OF 
HAWAII. AS THE THE RIDGE SHIFTS SE THROUGH THE NEXT 48 
HOURS...THE CUT OFF LOW WILL OPEN UP AND LIFT OUT TO THE NE. A 
1034 MB SURFACE HIGH SHIFTS SWD ALONG WITH THE UPPER RIDGING 
THROUGH MON. THIS WILL MAINTAIN FRESH NLY FLOW OFF THE BAJA 
COAST...ACCOMPANIED BY NLY SWELL TO 12 FT. IN ADDITION...FRESH 
TO STRONG TRADES S OF THE RIDGE WILL PERSIST GENERALLY W OF 
125W. FURTHER SOUTH...CONVECTION CONTINUES TO FLARE NEAR 115W 
WHERE A SURFACE TROUGH INTERSECTS THE ITCZ. THE TROUGH AND 
RELATED CONVECTION WILL CONTINUE SLOWLY W THROUGH 48 HOURS 
REACHING 130W...WITH SOME ENHANCEMENT FROM DIVERGENT FLOW ALOFT.

$$
CHRISTENSEN