000
AXPZ20 KNHC 052201
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI MAR 05 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 
2100 UTC.

...ITCZ...
THE ITCZ AXIS IS ALONG 04N77W TO 06N90W TO 05N105W TO 01N118W TO 
04N140W. SCATTERED MODERATE ISOLATED STRONG FROM 03N TO 07N 
BETWEEN 88W AND 97W. SIMILAR CONVECTION IS FROM 02N TO 06N 
BETWEEN 109W AND 113W. 

...DISCUSSION...
A DIGGING UPPER LEVEL TROUGH IS MOVING ACROSS THE NW PORTION OF 
THE DISCUSSION AREA WITH AXIS ALONG 30N128W TO 26N140W. THIS 
TROUGH WILL CONTINUE TO MOVE EWD AS A CUT-OFF UPPER LOW SLIDES 
SWD ALONG THE COAST OF CALIFORNIA AND BRUSHES THE FAR NE PORTION 
OF THE DISCUSSION AREA WITHIN 24-36 HOURS. THE DIGGING TROUGH 
AND CUT OFF LOW WILL PROVIDE SUPPORT FOR A COLD FRONT THAT IS 
EXPECTED TO MOVE INTO THE FAR N WATERS TONIGHT. A REINFORCING 
COLD FRONT WITH STRONGER WINDS BEHIND IT WILL FOLLOW THE PRIMARY 
FRONT ENTERING THE AREA WITHIN AROUND 24 HOURS. WINDS IN THE 20 
TO 30 KT RANGE WITH HIGHER GUSTS AND SEAS OF UP TO 18 FT IN NW 
SWELL ARE EXPECTED IN THE WAKE OF THE SECONDARY FRONT. THERE IS 
THE POTENTIAL FOR GALE FORCE WINDS BEHIND THE FRONT PER THE GFS 
MODEL...HOWEVER THE OTHER NWP MODELS DO NOT SHOW WINDS AS 
STRONG. 

A BROAD RIDGE DOMINATES THE AREA TO THE EAST OF THE DIGGING 
TROUGH...GENERALLY N OF 20N AND E OF 125W...INCLUDING BAJA 
CALIFORNIA PENINSULA AND NORTH-CENTRAL MEXICO. SATELLITE DERIVED 
WINDS INDICATED A BRANCH OF THE SUBTROPICAL JET WITH CORE JET 
SPEEDS OF 120-150 KT CURVING ANTICYCLONICALLY ACROSS THE N 
PERIPHERY OF THE RIDGE. THE JET ENTERS THE AREA NEAR 18N140W AND 
TURNS NE ACROSS CENTRAL BAJA CALIFORNIA...NORTHERN MEXICO INTO 
TEXAS AND THE GULF COAST. THIS JET IS TRANSPORTING ABUNDANT MID 
AND UPPER LEVEL MOISTURE ACROSS SOUTHERN BAJA CALIFORNIA AND 
MEXICO. 

IN THE DEEP TROPICS...A STABLE PATTERN REMAINS WITH AN EAST TO 
WEST UPPER LEVEL RIDGE EXTENDING FROM COLOMBIA ACROSS PANAMA AND 
COSTA RICA TO NEAR 9N95W THEN NW TO NEAR 14N104W. THIS RIDGE 
ALSO COVERS CENTRAL AMERICA AND SOUTHERN MEXICO. AN UPPER LEVEL 
CYCLONIC CIRCULATION EMBEDDED WITHIN AN UPPER TROUGH IS LOCATED 
NEAR 4N104W. S TO SW UPPER LEVEL WINDS N OF THE RIDGE AND E OF 
THE CIRCULATION ARE TRANSPORTING SOME UPPER LEVEL MOISTURE 
ACROSS NORTHERN CENTRAL AMERICA INTO THE CENTRAL CARIBBEAN SEA. 
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 9N102W. 
THIS FEATURE IS HELPING TO INDUCE SOME CONVECTION ALONG THE 
ITCZ. A WEAK SURFACE TROUGH EMBEDDED WITHIN THE ITCZ EXTENDS 
FROM 8N92W TO 2N95W. SCATTERED MODERATE CONVECTION IS MAINLY 
WHERE THE TROUGH AXIS MEETS THE ITCZ.  

AT THE SURFACE...A RIDGE OF HIGH PRESSURE DOMINATES THE AREA N 
OF 15N AND W OF 110W. A BROAD SWATH OF NE TO E TRADES OF 20 TO 
25 KT IS NOTED ON THE SOUTHERN PERIPHERY OF THE RIDGE. A WINDSAT 
PASS FROM THIS MORNING AND A RECENT ASCAT PASS CONFIRMED THE 
PRESENCE OF THE TRADES WHICH WERE CONFINED TO AN AREA FROM 4N TO 
20N W OF 120W. LITTLE CHANGE IN THE AREA OF THESE WINDS IS 
EXPECTED OVER THE NEXT 48 HOURS AS HIGH PRESSURE CONTINUES TO 
BUILD EWD. 

A TRAIN OF LONG PERIOD...16-17 SECONDS...SWELLS IS SPREADING SE 
ACROSS THE FORECAST AREA WITH SEA HEIGHTS OF UP TO 12 FT.  
ANOTHER SET OF NW SWELL IS JUST ENTERING THE FAR NW PORTION OF 
AREA IN THE WAKE OF THE NEXT COLD FRONT EXPECTED TO ENTER THE 
FAR N WATERS TONIGHT.  

GAP WINDS...
WINDS IN THE GULF OF TEHUANTEPEC CONTINUE AT 20 TO 25 KT AND ARE 
EXPECTED TO PERSIST FOR ANOTHER 48 HOURS. 

A 1516 UTC ASCAT PASS INDICATED WINDS OF 20 TO 25 KT IN THE GULF 
OF PAPAGAYO. THESE WINDS MAY INCREASE TO 30 KT LATE TONIGHT INTO 
THE MORNING HOURS DURING THE TIME OF MAXIMUM DRAINAGE FLOW IN 
THE AREA. OVERALL THE AREA OF WINDS ARE FORECAST TO PERSIST 
THROUGH THE NEXT FEW DAYS AS HIGH PRESSURE BUILDS SOUTHWARD 
ACROSS CENTRAL AMERICA. THIS SAME PATTERN IS ALSO PRODUCING AN 
INCREASE IN WINDS AND SEAS ACROSS THE GULF OF PANAMA. THESE 
WINDS ARE EXPECTED TO REMAIN IN THE 20 TO 25 KT RANGE ACROSS 
THIS AREA WITHIN THE NEXT FEW DAYS.  

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

$$
GR