000
AXPZ20 KNHC 131523
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON SEP 13 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 
1445 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 10N86W 
TO 11N97W TO LOW NEAR 11N113W TO LOW NEAR 10N123W TO 08N128W TO 
LOW NEAR 12N133W TO 08N140W. SCATTERED MODERATE CONVECTION IS 
NOTED WITHIN 120 NM S OF THE ITCZ AXIS BETWEEN 92W AND 96W AND 
BETWEEN 106W AND 112W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 
123W AND 135W. THREE SURFACE LOWS ARE EMBEDDED IN THE ITCZ. THE 
1010 MB EASTERN LOW LIES NEAR 11N113W...A 1010 MB LOW LIES NEAR 
10N124W...AND THE WESTERN 1011 MB LOW LIES NEAR 12N133W.


...DISCUSSION...

AN EXPANSIVE ANTICYCLONE CENTERED OVER SE TEXAS EXTENDS A RIDGE 
SOUTHWEST THROUGH A NEWLY DEVELOPING ANTICYCLONE OVER THE 
SOUTHERN GULF OF CALIFORNIA NEAR 25N108W AND CONTINUES TO 
18N120W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS 
ENHANCING THE SCATTERED MODERATE CONVECTION FOUND WITHIN 150 NM 
OF THE COAST OF MAINLAND MEXICO FROM 20N TO 25N. UPPER LEVEL 
DIFFLUENCE CAN ALSO BE FOUND BETWEEN THE E TO SE FLOW ON THE FAR 
SW SIDE OF THE ANTICYCLONE AND NE TO E FLOW WITHIN APPROXIMATELY 
300 NM W OF AN UPPER TROUGH EXTENDING FROM THE NW CARIBBEAN NEAR 
21N84W THROUGH CENTRAL AMERICA TO 10N90W. THIS DIFFLUENCE IS 
ENHANCING CONVECTION SW OF TEHAUNTEPEC WITH NUMEROUS MODERATE TO 
STRONG CONVECTION NOTED WITHIN 210 NM S OF COAST OF MEXICO 
BETWEEN 95W AND 100W. N WINDS FUNNELING THROUGH THE 
ISTHMUS OF TEHAUNTEPEC ARE EXPECTED TO BE AROUND 20 KT THROUGH 
TUE NIGHT AS A SURFACE TROUGH LINGERS FROM THE SW GULF OF MEXICO 
INTO THE ISTHMUS...DIRECTING NORTHERLY FLOW ON ITS W SIDE FROM 
HIGHER PRES OVER THE NORTHERN GULF COASTAL PLAIN SOUTHWARD INTO 
THE EASTERN PACIFIC.

A SW TO W UPPER JET LIES OVER FAR N WATERS. THIS MOSTLY ZONAL 
FLOW LIES BEHIND A MEAN TROUGH WHOSE LEADING EDGE IS NEAR THE 
CALIFORNIA COAST. THE REFLECTION OF THIS TROUGHING AT THE 
SURFACE IS EXPANDING THE USUAL TROUGHING OVER THE GULF OF 
CALIFORNIA NORTHWARD INTO CALIFORNIA AND OFFSHORE. THE PRES 
GRADIENT BETWEEN THIS TROUGHING AND THE SUBTROPICAL 
RIDGE...WHICH LIES FROM A 1023 MB HIGH NEAR 33N139W TO 
18N110W...IS YIELDING NW TO N WINDS IN THE 15 TO 20 KT RANGE OFF 
THE COAST OF NORTHERN BAJA CALIFORNIA ACCORDING TO SHIPS C6FV9 
NEAR 30N116W REPORTING 17 KT AND UNKNOWN SHIP NEAR 27N118W 
REPORTING 18 KT AT 1200 UTC. WINDS ARE EXPECTED TO BE STRONGEST 
HERE DURING THE OVERNIGHT HOURS.

$$
SCHAUER