000
AXPZ20 KNHC 150915
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAR 15 2011

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 05N85W 
TO 06N113W TO 05N123W TO 05N130W TO 04N140W. SCATTERED MODERATE 
CONVECTION IS WITHIN 150 NM N AND 120 NM S OF THE ITCZ AXIS W OF 
135W...BETWEEN 90 NM AND 150 NM S OF THE ITCZ AXIS BETWEEN 129W 
AND 131W...AND BETWEEN 90 NM AND 210 NM N OF THE ITCZ AXIS 
BETWEEN 117W AND 123W. 

...DISCUSSION...
AN UPPER TROUGH EXTENDS FROM NW MEXICO NEAR 26N107W THROUGH 
24N124W TO 15N140W AND THEN S OF HAWAII NEAR 10N. A 60-80 KT 
UPPER JET LIES BETWEEN THE TROUGH AXIS AND 20N. THIS JET TURNS 
MORE NORTHWESTERLY AS IT MOVES INTO MEXICO. THIS JET MERGES WITH 
A 40-50 KT SOUTHWESTERLY JET ALOFT THAT IS CENTERED FROM 00N100W 
TO NEAR THE GULF OF FONSECA 13N87W. THE RESULTING CONFLUENT FLOW 
OVER SOUTHERN MEXICO AND CENTRAL AMERICA COUPLED WITH SUBSIDENT 
CONDITIONS INDICATED ON WATER VAPOR IMAGERY IS PROHIBITING THE 
DEVELOPMENT OF DEEP CONVECTION OVER THE AREA S OF 20N AND E OF 
110W. THE UPPER TROUGH WILL BE PUSHED SLIGHTLY SOUTHEASTWARD 
OVER THE NEXT TWO DAYS AS A BROAD UPPER TROUGH MOVES INTO THE 
NORTHERN PORTION OF THE FORECAST AREA. A WEAK COLD FRONT 
ASSOCIATED WITH THIS BROAD TROUGH WILL ENTER AND DISSIPATE OVER 
NW WATERS WED MORNING AFTER BRIEFLY BRINGING N WINDS TO 20 KT. 
THIS FRONT WILL USHER IN A NEW BATCH OF NW SWELL WITH SEAS AS 
HIGH AS 16-18 FT OVER NW WATERS EARLY WED. 

1028 MB HIGH PRES CURRENTLY LIES NEAR 29N128W AND IS FORECAST TO 
MAINTAIN ITS STRENGTH AS IT SHIFTS SOUTHWESTWARD AHEAD OF THE 
FRONT THROUGH WED MORNING. NEW HIGH PRES WILL BUILD NW OF THE 
AREA BEHIND THE FRONT LATER WED INTO THU MORNING. THE AREA OF 
FRESH TRADE WINDS...CURRENTLY FROM 06N TO 20N W OF 120W...WILL 
SHIFT SLIGHTLY WESTWARD TOMORROW AND THEN EXPAND NORTHWARD 
ACROSS MUCH OF THE AREA N OF 06N W OF 128W BY THU MORNING IN 
RESPONSE TO THE MOVEMENT OF THE HIGH. FRESH TO STRONG NW WINDS 
LIE E OF THE HIGH ALONG THE COAST OF THE BAJA CALIFORNIA 
PENINSULA...WITH SHIPS WAAT...DPLE AND PDBP ALL CONFIRMING WINDS 
IN THIS RANGE. THESE WINDS ARE EXPECTED TO BECOME FRESH BY TUE 
MORNING AND SHIFT SLIGHTLY WESTWARD ALONG WITH THE HIGH. BY THU 
MORNING...THE AREA OF FRESH WINDS WILL SHRINK NORTHWARD ALONG 
THE BAJA CALIFORNIA NORTE COAST.

CONVECTION NEAR THE ITCZ BETWEEN 117W AND 131W IS BEING ENHANCED 
BY BROAD DIFFLUENT FLOW ALOFT BETWEEN A TROUGH FROM 10N135W TO 
00N132W AND ANTICYCLONIC FLOW TO ITS EAST. THIS CONVECTION IS 
DESCRIBED IN THE ITCZ SECTION ABOVE. CONVECTION W OF 135W IS 
ASSOCIATED WITH DIFFLUENCE ALOFT ALONG A WEAK UPPER RIDGE AXIS 
BETWEEN THIS TROUGH AND THE AFOREMENTIONED TROUGH TO THE N. 

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS WILL FUNNEL THROUGH THE ISTHMUS OF 
TEHUANTEPEC BEGINNING THIS MORNING AS HIGH PRES BUILDS OVER NE 
MEXICO. WINDS WILL PULSE TO 25 KT IN THE MORNING HOURS WHEN 
DRAINAGE FLOW THROUGH THE PASS WILL BE AT ITS DIURNAL MAXIMUM. 

GULF OF PAPAGAYO...DRAINAGE FLOW OFF THE LANDMASS WILL HELP 
MAINTAIN WINDS AT THE ADVISORY LEVEL DURING THE EARLY MORNING 
HOURS THROUGH THE END OF THE FORECAST PERIOD ON THU MORNING.

$$
SCHAUER