000
AXPZ20 KNHC 130924
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN MAR 13 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0645 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 02N95W 
TO 05N100W TO 05N128W TO 08N140W. SCATTERED MODERATE CONVECTION 
LIES WITHIN 120 NM N AND 75 NM S OF THE ITCZ AXIS W OF 128W. 
SCATTERED MODERATE CONVECTION CAN ALSO BE FOUND BETWEEN 90 NM 
AND 150 NM S OF THE ITCZ AXIS BETWEEN 127W AND 129W.

...DISCUSSION...
A POSITIVELY TILTED UPPER LEVEL TROUGH EXTENDS FROM THE NORTHERN 
GULF OF CALIFORNIA NEAR 32N115W TO BEYOND 22N140W. A 70-90 KT 
JET LIES AHEAD OF THE TROUGH AXIS AND IS TRANSPORTING A THINNING 
SWATH OF MID TO UPPER LEVEL TROPICAL MOSITURE NORTHEASTWARD 
FROM S OF HAWAII ACROSS BAJA CALIFORNIA SUR AND INTO NW MEXICO. 
THIS TROUGH IS FORECAST TO SPLIT LATER TODAY AS A DEEP-LAYER 
TROUGH LOCATED JUST NW OF THE AREA SWEEPS IN AND BRIEFLY PICKS 
UP THE LINGERING TROUGHING OVER NW WATERS WHILE THE NORTHERN 
PORTION OF THE POSITIVELY TILTED TROUGH MOVES E INTO NORTH 
AMERICA. THE DEEP LAYER TROUGH HAS MORE PLENTIFUL MID TO UPPER 
LEVEL MOISTURE ASSOCIATED WITH IT ALLOWING FOR DENSE CIRRUS 
WHICH IS PASSING OVER DENSE STRATOCUMULUS OVER FAR NW WATERS 
THIS MORNING. THE DEEP LAYER TROUGH SUPPORTS A COLD FRONT THAT 
IS FORECAST TO APPROACH THE FAR NW CORNER OF THE REGION LATER 
TODAY AND THEN LIFT NE AWAY FROM THE AREA BY TONIGHT AS THE 
TROUGH ALOFT PUSHES NORTHEASTWARD AND TURNS NEGATIVE TILT. SW 
WINDS OF 20 KT WERE REPORTED AHEAD OF THE FRONT AT 0256 UTC BY 
THE WINDSAT SCATTEROMETER AS WELL AS THE 0550 UTC ASCAT PASS.  
THESE WINDS SHOULD REMAIN OVER THE NW CORNER THROUGH THE DAY. A 
FRESH BATCH OF NW SWELL ASSOCIATED WITH THIS SYSTEM WILL BRING 
SEAS TO 15 FT IN NW WATERS MON MORNING BEFORE DAMPENING AS THE 
SWELL SPREADS SE. 

1025 MB HIGH PRES CURRENTLY LIES NEAR 29N125W AND IS FORECAST TO 
GRADUALLY STRENGTHEN AS IT SHIFTS SLIGHTLY N THROUGH MON MORNING 
AND SLIGHTLY W THEREAFTER. THE AREA OF FRESH TRADE 
WINDS...CURRENTLY FROM 07N TO 11N W OF 130W...WILL EXPAND NORTH 
AND EAST IN RESPONSE TO THE STRENGTHENING HIGH. A SMALL AREA OF 
20 KT NW WINDS LIES E OF THE HIGH ALONG THE COAST OF BAJA 
CALIFORNIA NORTE N OF 29N. THIS AREA OF 20 KT WINDS IS ALSO 
EXPECTED TO EXPAND SOUTHWARD AND WESTWARD IN RESPONSE TO THE 
STRENGTHENING HIGH OVER THE NEXT FEW DAYS.

THERE IS NO SIGNIFICANT DEEP CONVECTION OVER THE TROPICAL REGION 
E OF 125W. STRONG SUBSIDENCE MARKS MUCH OF THE AREA S OF 20N AND 
E OF 115W...WITH CONFLUENT FLOW ALOFT NOTED IN THE VICINITY OF 
THE GULFS OF FONSECA AND PAPAGAYO. CONVECTION NEAR THE ITCZ OVER 
THE WESTERN PORTION OF THE FORECAST AREA IS BEING ENHANCED BY 
DIFFLUENT FLOW ALOFT BETWEEN A WEAKENING UPPER LOW NEAR 04N140W 
AND AN UPPER RIDGE TO ITS N THAT EXTENDS OVER FORECAST WATERS 
FROM 10N140W TO AN ANTICYCLONE CENTERED NEAR 11N117W. THIS 
CONVECTION IS DESCRIBED IN THE ITCZ SECTION ABOVE.

GAP WINDS...
GULF OF TEHUANTEPEC...WINDS HAVE DIMINISHED BELOW ADVISORY 
CRITERIA IN THE GULF OF TEHUANTEPEC. THE 0404 UTC ASCAT PASS 
SHOWS ONLY LIGHT AND VARIABLE WINDS THERE.

GULF OF PAPAGAYO...SHIP A80H4 NEAR 10.5N87W REPORTED 20 KT NE 
WINDS IN THE GULF OF PAPAGAYO AT 0600 UTC. THESE NE TO E WINDS 
OF 20 KT ARE EXPECTED TO CONTINUE THROUGH SUN AND DIMINISH 
SOMEWHAT MON. HOWEVER...DRAINAGE FLOW OFF THE LANDMASS WILL HELP 
MAINTAIN WINDS TO THE ADVISORY LEVEL DURING THE EARLY MORNING 
HOURS AT THE END OF THE FORECAST PERIOD ON TUE.   

GULF OF PANAMA...THE 0222 UTC ASCAT PASS CONTINUES TO SHOW 20 KT 
WINDS IN THE GULF OF PANAMA. THESE WINDS ARE EXPECTED TO 
DIMINISH BY MON AFTERNOON AS HIGH PRES OVER CENTRAL AMERICA 
ERODES CAUSING THE PRES GRADIENT TO DIMINISH OVER THE GULF OF 
PANAMA BETWEEN HIGH PRES TO THE N AND THE COLOMBIAN LOW.

$$
SCHAUER