000
AXPZ20 KNHC 211536
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN MAR 21 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
AXIS ALONG 03N77W TO 04N85W TO 05N104W TO 02.5N120W TO 03N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM 
EITHER SIDE OF AXIS E OF 113W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITHIN 75 NM EITHER SIDE OF AXIS W OF 134W. 

...DISCUSSION...
POSITIVELY TILTED UPPER TROUGH HAS ENTERED THE W PART OF THE 
AREA N OF 20N....WITH UPPER LEVEL RIDGE PREVAILING N OF 20N OVER 
THE E PART OF THE AREA. SW FLOW ON THE E SIDE OF THE TROUGH IS 
ADVECTING MID AND UPPER LEVEL MOISTURE OVER CALIFORNIA. IN THE 
DEEP TROPICS...ITCZ CONVECTION CONTINUES TO MAINTAIN UPPER LEVEL 
RIDGING ALONG 10N. 

THE PRESSURE GRADIENT BETWEEN THE ITCZ AND DISSIPATING SURFACE 
HIGH PRESSURE 1024 MB CENTERED NEAR 33N125W IS MAINTAINING A 
SMALL AREA OF 20 KT TRADES FROM 06N TO 15N W OF 125W. THE 
PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED HIGH PRESSURE AND 
TROUGHING OVER THE SIERRA MADRE OCCIDENTAL ARE SUPPORTING 20 KT 
WINDS OVER THE GULF OF CALIFORNIA. AS THE HIGH PRESSURE 
DISSIPATES...WINDS OVER THE GULF OF CALIFORNIA WILL DIMINISH 
BELOW 20 KT MON. A DISSIPATING STATIONARY FRONT EXTENDS FROM 
30N137W TO 26N140W. THIS FRONT IS EXPECTED TO DISSIPATE BY MON. 
HIGH PRESSURE WILL THEN BUILD N OF THE AREA MON WHICH WILL 
INCREASE THE COVERAGE OF FRESH TO STRONG TRADES W OF 125W BY 
TUE.   

NW SWELLS GENERATED BEHIND THE FRONT IS SPREADING S AND E ACROSS 
THE AREA N OF 15N AND W OF 125W. THESE SWELLS WILL CONTINUE TO 
SPREAD S AND E THROUGH THE FORECAST PERIOD. MERGING SW AND NW 
SWELLS PREVAIL S OF 15N W OF 96W.   

GAP WINDS...
NORTHERLY WINDS BEHIND A STRONG COLD FRONT CROSSING THE GULF OF 
MEXICO WILL FUNNEL THROUGH THE ISTHMUS INTO GULF OF 
TEHUANTEPEC.  WINDS ARE EXPECTED TO REACH GALE FORCE THIS 
AFTERNOON. SURFACE HIGH PRESSURE BUILDING BEHIND THE COLD FRONT 
IN THE GULF OF MEXICO WILL SHIFT SE...VEERING THE WINDS AND 
DECREASING THE WINDS FUNNELING THROUGH THE ISTHMUS. AS A 
RESULT...WINDS ARE EXPECTED TO DIMINISH BELOW GALE FORCE MON. 

STRONG TRADES IN THE WESTERN CARIBBEAN WILL FUNNEL INTO THE GULF 
OF PAPAGAYO INCREASING WINDS TO 20 KT TONIGHT...AND REMAINING 
THROUGH THE FORECAST PERIOD. 

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

$$
AL