000
AXPZ20 KNHC 152159
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAR 15 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 
2100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG AXIS 4N77W 7N115W 7N140W. SCATTERED 
MODERATE TO STRONG CONVECTION WITHIN 120 NM N OF AXIS BETWEEN 
87W AND 91W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 180 
NM N OF AXIS BETWEEN 110W AND 113W. SCATTERED MODERATE 
CONVECTION WITHIN 150 NM OF AXIS BETWEEN 128W AND 132W.

...DISCUSSION...

E OF 110W...
WATER VAPOR IMAGERY SHOWS AN UPPER RIDGE CENTERED OVER THE 
CENTRAL CARIBBEAN EXTENDING WEST TO AROUND 100W. DIVERGENCE 
ALOFT ON THE WESTERN EDGE OF THIS UPPER RIDGE IS ENHANCING 
MODEST CONVECTION JUST N OF THE ITCZ AROUND 90W...AND IS 
SUSTAINING A WEAK SURFACE TROUGH NEAR 100W. WATER VAPOR IMAGERY 
ALSO DEPICTS A SHORT WAVE TROUGH IS MOVING EASTWARD THROUGH 107W 
NEAR MANZANILLO MEXICO. DESPITE SWLY FLOW ALOFT BETWEEN THE 
SHORT WAVE TROUGH AND THE UPPER RIDGE TO THE EAST...DEEP LAYER 
ATMOSPHERE REMAINS FAIRLY DRY...LIMITING CONVECTIVE DEVELOPMENT. 
FURTHER TO SOUTH...ASCAT IMAGERY SHOWS LIGHT NLY FLOW THROUGH 
PANAMA ISTHMUS. SHIP OBSERVATIONS SHOW SEA HEIGHTS GENERALLY 
UNDER 4 FEET IN ALL AREAS E OF 110W DUE TO THE RELATIVELY LIGHT 
WINDS AND LACK OF SIGNIFICANT SWELL. LOOKING AHEAD...NOT MUCH 
CHANGE IS EXPECTED OVER THE NEXT COUPLE OF DAYS. HOWEVER...A 
STRONG COLD FRONT WILL EMERGE INTO THE GULF OF MEXICO TUE...AND 
PUSH STRONG WINDS INTO THE GULF OF TEHUANTEPEC BY MID WEEK. 
FRESH ELY FLOW IS LIKELY THROUGH THE GULF OF PAPAGAYO AS WELL 
TUE INTO WED AS HIGH PRES OVER W ATLC INCREASES TRADES OVER THE 
CARIBBEAN. 

W OF 115W...
AN UPPER TROUGH FROM CENTRAL CALIFORNIA TO NEAR 28N140W IS 
SHIFTING EAST AND ALIGNING MORE N-S AHEAD OF A BROAD UPPER RIDGE 
CENTERED NEAR 33N150W. AS THE UPPER RIDGE MOVES EAST...AN 
ASSOCIATED STRONG 1038 MB SURFACE HIGH CURRENTLY NEAR 38N141W 
WILL SHIFT E AS WELL. AS A RESULT...ALREADY STRONG NLY SURFACE 
FLOW DOWN THE CALIFORNIA AND NRN BAJA COASTS WILL INCREASE TO 
NEAR 30 KT BY TOMORROW. THE STRONG SURFACE HIGH WILL ALSO 
MAINTAIN FRESH TO STRONG TRADES MAINLY FROM THE SOUTHERN TIP OF 
BAJA SW TO NEAR 5N140W. A FEW SHIP OBSERVATIONS ALONG WITH A 
JASON ALTIMETER PASS SHOW SEA HEIGHTS GENERALLY TO 9 FT OFF BAJA 
COAST IN NLY SWELL. GIVEN THE FETCH AND DURATION OF THE NLY 
FLOW...WAVEWATCH MODEL SHOWS COMBINED SEAS HEIGHTS TO 17 FT W OF 
125W. THE STRONG NLY WINDS AND HIGH SEAS WILL GRADUALLY SUBSIDE 
THROUGH TUE AS THE HIGH PRES SHIFTS FURTHER E...BUT THE FRESH TO 
STRONG TRADES WILL PERSIST INTO AT LEAST MIDWEEK. MEANWHILE 
FURTHER S...AN CUTOFF UPPER CYCLONIC CIRCULATION IS ENHANCING 
MODERATE TO STRONG CONVECTION OVER THE ITCZ AS DESCRIBED ABOVE. 
WHILE THIS WILL LARGELY DISSIPATE OVERNIGHT...THE PERSISTENT 
ENHANCED TRADE WIND CONVERGENCE ALONG THE ITCZ WILL KEEP SMALL 
POCKETS OF CONVECTION ACTIVE W OF 120W THROUGH THE REMAINDER OF 
THE WEEK.

$$
CHRISTENSEN