000
AXPZ20 KNHC 172135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAR 17 2010

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 
2000 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED FROM 06N77W TO 
06N85W TO 04N95W TO 05N105W TO 03N140W. SCATTERED MODERATE 
CONVECTION WAS WITHIN 150 NM EITHER SIDE OF THE ITCZ AXIS E OF 
87W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 180 NM N 
AND 75 NM S OF THE ITCZ AXIS BETWEEN 122W AND A TROUGH EMBEDDED 
IN THE ITCZ FROM 08N132W TO 02N134W AS WELL AS WITHIN 120 NM 
EITHER SIDE OF THE ITCZ AXIS W OF 137W.

...DISCUSSION...

N OF 20N...
A WEAK MID TO UPPER LEVEL TROUGH IN PLACE OVER N WATERS WILL 
QUICKLY MOVE NE INTO THE W COAST OF THE U.S. AS THE RIDGE TO ITS 
SOUTH BUILDS NORTHWARD AHEAD OF THE NEXT TROUGH. THIS SECOND 
TROUGH WILL ENTER N WATERS ON THU AND SEND A COLD FRONT WITH NW 
TO N WINDS AT 20 KT INTO THE FORECAST AREA. WHILE THE COLD FRONT 
ASSOCIATED WITH THE UPPER LEVEL TROUGH CURRENTLY OVER N WATERS 
HAS DISSIPATED...THE PRES GRADIENT BETWEEN THE RIDGE AXIS OVER 
NW WATERS AND TROUGHING ON EITHER SIDE OF IT AT THE SURFACE HAS 
ALLOWED FOR WINDS IN THE 20 TO 25 KT RANGE IN WATERS N OF 24N W 
OF 128W...WITH WINDS SHIFTING FROM NE TO SE ACROSS FAR W WATERS. 
THERE HAVE BEEN SEVERAL SHIP REPORTS IN THIS REGION BETWEEN 1600 
AND 2000 UTC THAT HAVE CONFIRMED THE STRONG WINDS HERE. THESE 
WINDS WILL MOVE NE OF AREA WITH THE MID TO UPPER LEVEL TROUGH 
OVERNIGHT TONIGHT. MEANWHILE...20 KT SE WINDS WILL CONTINUE 
AHEAD OF THAT NEXT COLD FRONT AS IT APPROACHES THU. 

S OF 20N...
BOTH THE 1430 UTC WINDSAT AND 1750 UTC ASCAT PASSES SHOW STRONG 
NE TRADE WINDS PRIMARILY FROM 05N TO 11N W OF 125W. THESE TRADE 
WINDS WILL DIMINISH TO 20 KT AND SHRINK SW AND AS THE RIDGE AXIS 
TO THE N WEAKENS AHEAD OF THE NEW FRONT MOVING INTO NW WATERS 
THU AND FRI. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 
08N132W TO 02N132W WITHIN THE AREA OF STRONG TRADE WINDS. 
MODERATE TO STRONG CONVECTION CAN BE FOUND ON EITHER SIDE OF 
THIS TROUGH. THIS TROUGH LIES UNDER A REGION OF STRONG UPPER 
DIFFLUENCE BETWEEN TROUGHING JUST W OF THE AREA AND THE BROAD 
UPPER RIDGE TO THE NE. ANOTHER TROUGH IS EMBEDDED IN THE ITCZ 
FROM 10N106W TO 02N108W HAS LITTLE CONVECTION ASSOCIATED WITH 
IT. FARTHER E...A STRONG UPPER RIDGE AXIS EXTENDS FROM THE 
PANAMA/COLOMBIA BOARDER TO 06N115W. THE UPPER DIFFLUENCE 
ASSOCIATED WITH THIS RIDGE IS HELPING STIMULATE CONVECTION ALONG 
THE ITCZ E OF 87W.

GAP WINDS...
GALE FORCE WINDS ARE AFFECTING THE GULF OF TEHUANTEPEC AS STRONG 
HIGH PRES BUILDS OVER THE WESTERN GULF OF MEXICO AND TIGHTENS 
THE PRESSURE GRADIENT OVER SOUTHERN MEXICO. GALES ARE EXPECTED 
TO DIMINISH FRI MORNING AND WINDS WILL QUICKLY DROP BELOW 20 KT 
FRI AFTERNOON. TO THE S...SHIP ZCDG4 REPORTED E WINDS ALONG TO 
COAST OF THE GULF OF PAPAGAYO FROM 20-26 KTS BETWEEN 1500 TO 
1700 UTC. AS HIGH PRES OVER THE WESTERN CARIBBEAN CONTINUES TO 
BUILD TOMORROW...LOOK FOR THESE WINDS TO SPREAD DOWNSTREAM W OF 
90W. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
SCHAUER