000
AXPZ20 KNHC 090957
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT MAR 09 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS SW FROM THE COAST OF COSTA RICA AT 
07N85W TO  03N90W WHERE SCATTEROMETER WINDS INDICATE A 
TRANSITION TO AN ITCZ. THE ITCZ THEN CONTINUES W TO 02N120W. 
ISOLATED MODERATE CONVECTION IS NOTED WITHIN 30 NM EITHER SIDE 
OF A LINE FROM 01N100W TO 02N119W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 60 NM EITHER SIDE OF A LINE 
FROM 05N126W TO 08N131W. ISOLATED MODERATE CONVECTION IS 
POSSIBLE UNDER A DENSE CIRRUS SHIELD OBSERVED FROM 10N TO 22N 
BETWEEN 119W AND 140W.

...DISCUSSION...

A DEEP LAYERED CYCLONE IS OVER NW ARIZONA WITH A DEEP LAYERED 
TROUGH EXTENDING FROM 32N111W TO A BASE AT 26N121W. AN UPPER 
CYCLONE HAS CUT OFF AT 16N143W. AN UPPER ANTICYCLONE IS CENTERED 
AT 11N111W...WITH AN UPPER RIDGE THROUGH 26N135W TO A CREST  
AT 35N136W SETTING UP A LARGE AREA OF UPPER DIFFLUENCE BETWEEN 
THE TWO UPPER TROUGHS. DENSE DEBRIS MOISTURE IS NOTED WITHIN THE 
UPPER RIDGE FROM 05N TO 23N BETWEEN 120W AND 140W...WITH THE 
MOISTURE THEN CONCENTRATING INTO A 600 NM WIDE PLUME THAT MOVES 
E ACROSS CENTRAL OLD MEXICO...THEN TURNING NE ACROSS THE NW GULF 
OF MEXICO IN RESPONSE TO THE WESTERN CONUS TROUGH PREVIOUSLY 
DESCRIBED. AVIATORS TAKE NOTE THAT TRANSVERSE CIRRUS BANDING IS 
OBSERVED ALONG 20N BETWEEN 110W AND 130W...SUGGESTING UPPER 
LEVEL TURBULENCE. 
   
AN UPPER RIDGE EXTENDS NW FROM COLOMBIA ACROSS CENTRAL AMERICA 
TO GUATEMALA. DRY UPPER AIR IS SUPPRESSING CONVECTION ACROSS THE 
TROPICS E OF 100W.

A SURFACE RIDGE EXTENDS FROM 32N131W TO 18N106W. NW LOW LEVEL 
WINDS AT 15 TO 20 KT TO THE NE OF THE RIDGE ARE EXPECTED TO 
STRENGTHEN TO 20 TO 25 KT LATE TODAY. SEAS 8 TO 11 FT IN NW 
SWELL ARE ALREADY REACHING THE BAJA CALIFORNIA PENINSULA N OF 
27N...AND EXPECTED TO SPREAD S REACHING THE WESTERN SHORE S OF 
27N LATER TODAY. THE GRADIENT WILL BEGIN TO RELAX ON SUN. THE 
GRADIENT IS ALSO EXPECTED TO TIGHTEN SW OF THE RIDGE TONIGHT 
INCREASING THE NE TRADES TO 20 TO 25 KT ACROSS THE TROPICS FROM 
03N TO 22N BETWEEN 110W AND 140W. THIS AREA OF ENHANCED NE 
TRADES WILL GRADUALLY SHRINK THROUGH OUT NEXT WEEK.   

.GULF OF CALIFORNIA...A TROUGH WILL DEEPEN OVER INTERIOR OLD 
MEXICO AND TIGHTEN THE GRADIENT WITH NW WINDS INCREASING TO 15 
TO 20 KT TONIGHT...AND FURTHER INCREASING TO 20 TO 25 KT BY LATE 
SUN. THE GRADIENT WILL BEGIN TO RELAX SOME SUN NIGHT...BUT 
MAINTAIN NW 20 KT THROUGH LATE MON NIGHT.

GULF OF PAPAGAYO...NE WINDS WILL CONTINUE TO PULSE AT 20 TO 25 
KT ACROSS THE WATERS FROM 09N TO 11.5N BETWEEN 86W AND 88W 
THROUGH EARLY SUN...THEN DIMINISH TO 15 TO 20 KT LATE SUN.

GULF OF TEHUANTEPEC...THE NEXT TEHUANTEPEC EVENT WILL BEGIN ON 
MON NIGHT. LATEST GUIDANCE IS MORE AGGRESSIVE THAT YESTERDAYS 
MODEL RUNS...AND NOW SUGGEST MINIMAL GALE CONDITIONS BEGINNING 
AROUND MIDNIGHT MON NIGHT AND CONTINUING THROUGH SUNRISE THU.
   
$$
NELSON