000
AXPZ20 KNHC 100909
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU SEP 10 2009

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 
0900 UTC.

...SPECIAL FEATURE...

AT 10/0900 UTC...HURRICANE LINDA IS NEAR 17.8N 129.6W MOVING 
NORTHWEST 0R 325 DEG AT 7 KT. MAXIMUM SUSTAINED WINDS AREA 70 KT 
WITH GUSTS TO 80 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 
985 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP5/WTPZ25 KNHC AND THE PUBLIC ADVISORY UNDER TCPEP5/ 
WTPZ35 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS 
OCCURRING WITHIN 60 NM OF LINDA'S CENTER. THE OVERALL CLOUD 
PATTERN HAS BECOME SLIGHTLY LESS ORGANIZED...AND THE EYE 
PREVIOUSLY SEEN ON CONVECTIONAL SATELLITE IMAGERY AND MICROWAVE 
DATA DISAPPEARED. AN INCREASING SHEAR FROM THE SW AND W...ALONG 
WITH SEA SURFACE TEMPERATURES COOLING BELOW 24 DEG C IN ABOUT 48 
HOURS...SHOULD RESULT IN WEAKENING. THE INTENSITY FORECAST CALLS 
FOR LINDA TO BE A TROPICAL DEPRESSION IN ABOUT 72 HOURS.

...TROPICAL WAVE...

A TROPICAL WAVE IS 92W N OF 5N MOVING WEST 10 TO 15 KT. A 
CLUSTER OF MODERATE TO STRONG CONVECTION IS AHEAD OF THE WAVE 
AXIS COVERING THE GULF OF TEHUANTEPEC. THIS ACTIVITY IS MOST 
LIKELY ASSOCIATED WITH A DIFFLUENT PATTERN ALOFT. SIMILAR 
CONVECTION IS NOTED NEAR THE INTERSECTION OF THE WAVE AXIS AND 
THE ITCZ.  

...THE ITCZ...

THE ITCZ AXIS IS ALONG 08N78W TO 10N100W TO 08N110W TO 
11N120W...THEN CONTINUING FROM 11N132W TO 12N140W. SCATTERED 
MODERATE TO STRONG CONVECTION WITHIN 100 NM N OF AXIS BETWEEN 
94W AND 96W. SCATTERED MODERATE CONVECTION NEAR 08N107W...AND 
NEAR 11N112W.

...DISCUSSION...

A MIDDLE/UPPER LEVEL TROUGH EXTENDED FROM A LOW CENTER NEAR 
32N126 SW TO AN ELONGATED MID TO UPPER LOW NEAR 24N135W. A LARGE 
UPPER RIDGE IS LOCATED NW OF THIS TROUGH. A LARGE UPPER LEVEL 
RIDGE...WITH AXIS ALONG 20N...DOMINATES THE AREA JUST E OF LINDA 
TO THE GULF OF MEXICO. THIS RIDGE IS ENHANCING CONVECTION ACROSS 
MUCH OF MEXICO AND NORTHERN CENTRAL AMERICA.  

ACROSS THE FAR ERN EPAC...A SHARP UPPER LEVEL TROUGH ACROSS THE 
CENTRAL AND SW CARIBBEAN EXTENDS SOUTH INTO COSTA RICA AND 
PANAMA...WITH BROAD CYCLONIC TURNING AND DIFFLUENCE AIDING IN 
DEEP CONVECTION ACROSS COLOMBIA AND ALONG THE ITCZ E OF 84W. 

A SURFACE RIDGE CONTINUES TO DOMINATE THE NORTHERN PORTION OF 
DISCUSSION AREA MAINLY N OF 22N W OF 115W. THE PRESSURE GRADIENT 
BETWEEN LINDA AND THE RIDGE IS PRODUCING AN AREA OF NE WINDS 20 
KT AND SEAS TO 9 FT...IN NE SWELL...MAINLY FROM 10N TO 20N AND W 
OF 133W. LOOKING AHEAD...A COLD FRONT WILL CLIP THE NW PORTION 
OF THE AREA DURING THE WEEKEND. 

OUTSIDE OF THE CIRCULATION OF LINDA...WINDS ARE GENERALLY LIGHT 
TO MODERATE ACROSS MUCH OF THE MARINE AREA...WITH MODEST SEAS.   
LARGE LONG PERIOD NW SWELLS OF AROUND 16 SECONDS WILL PROPAGATE  
ACROSS THE NW PART OF THE AREA...BUILDING SEAS TO 11 FT BY 
SATURDAY MORNING. CROSS EQUATORIAL SLY WINDS OF 20 KT AND SWELLS 
GENERATED BY A BROAD FIELD OF SE WINDS 20 TO 30 KT SOUTH OF THE 
EQUATOR WILL CONTINUE TO AFFECT THE FAR SOUTHERN PORTION MAINLY 
S OF 05N AND E OF 100W. 

$$
GR