000
AXPZ20 KNHC 071605
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC SAT SEP 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
                
...SPECIAL FEATURES...                                     

TROPICAL DEPRESSION LORENA NEAR 23.8N 111.8W AT 07/1500 UTC OR 
65 NM SSE OF CABO SAN LAZARO MEXICO AND 120 NM WNW OF CABO SAN 
LUCAS MEXICO MOVING WNW AT 7 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH 
GUSTS TO 40 KT. NUMEROUS MODERATE TO SCATTERED STRONG CONVECTION 
WAS NOTED AT 12 UTC ON SATELLITE IMAGERY...BUT THIS HAS SINCE 
DIMINISHED CONSIDERABLY. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. AN 
EARLIER BURST OF CONVECTION DURING THE EARLY MORNING HOURS IS 
STARTING TO DIMINISH. LORENA IS FORECAST TO BECOME A REMNANT LOW 
THIS EVENING...AND DISSIPATE BY EARLY MON NIGHT. ASSOCIATED SEAS 
WILL SUBSIDE TO LESS THAN 8 FT BY LATE SUN NIGHT.

...TROPICAL WAVES...

THE FAR SOUTHERN EXTENT OF A TROPICAL WAVE IS N OF 11N ALONG 
88W. ASSOCIATED CONVECTION IS DESCRIBED BELOW. THE NORTHERN 
PORTION IS IN THE PROCESS OF MOVING FROM THE GULF OF HONDURAS TO 
THE W OVER THE YUCATAN. THIS TROPICAL WAVE IS FORECAST TO BECOME 
ILL-DEFINED DURING THE NEXT 24 HOURS WITH LITTLE DIRECT IMPACT 
ON WINDS AND SEAS IN THE NE PACIFIC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

THE MONSOON TROUGH AXIS EXTENDS FROM 13N88W TO 11N100W...THEN 
RESUMES FROM 13N118W TO LOW PRES NEAR 09N130W 1010 MB TO 
09N140W. NO ITCZ IS PRESENT E OF 140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 30 NM EITHER SIDE OF 
THE MONSOON TROUGH BETWEEN 117W AND 125W. 



...DISCUSSION... 

AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 25N131W IS MAINTAINING 
DRY AND STABLE AIR OVER THE BASIN N OF 16N W OF 115W. A SECOND 
UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 21N114W...AND EXTENDS E 
TO W FROM CENTRAL MEXICO TO 125W. THIS FEATURE HAD BEEN AIDING 
LORENAS OUTFLOW WHILE ALSO PROVIDING SUPPORT FOR CONVECTION TO 
THE S ALONG A REFORMING PORTION OF THE MONSOON TROUGH OVER THE 
CENTRAL WATERS AS IS DESCRIBED ABOVE.

SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM S OF COAST 
OF MEXICO BETWEEN 100W AND 105W. THIS IS THE RESIDUAL CONVECTION 
MAINLY DUE TO OVERNIGHT DRAINAGE FLOW INTO THE PACIFIC COAST 
WATERS. MOISTURE LEVELS REMAIN HIGH OVER CENTRAL MEXICO IN THE 
WAKE OF TROPICAL DEPRESSION EIGHT THAT DISSIPATED OVER E CENTRAL 
MEXICO YESTERDAY.

THE COMBINATION OF A SLIGHT INCREASE IN SW FLOW IN THE LOWER 
LEVELS ALONG WITH UPPER DIVERGENCE S OF THE RIDGE ALOFT IS 
RESULTING IN SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
FROM 11N TO 15N BETWEEN 102W AND 105W.

A 1024 MB HIGH PRES IS CENTERED WELL N OF THE BASIN NEAR 
40N135W. THIS HAS BEEN ENHANCING NORTHERLY WINDS OFF THE COAST 
OF NORTHERN AND CENTRAL CALIFORNIA. AN OVERNIGHT ALTIMETER PASS 
INDICATED 6 TO 7 FT SEAS N OF 24N ALONG 120W...BACKING UP MWW3 
INITIALIZATIONS SHOWING N SWELL FROM THE STRONGER WINDS TO THE N 
DELIVERING 6 TO 7 FT SEAS N OF 24N BETWEEN 120W AND 125W. 

FARTHER SOUTH...GLOBAL MODELS SUGGEST A SURGE IN SW FLOW INTO 
THE MONSOON TROUGH STARTING MON FROM 07N TO 11N BETWEEN 102W AND 
120W. IN ADDITION...CROSS-EQUATORIAL SOUTHERLY SWELL WITH SEAS 
TO 8 FT WILL PUSH AS FAR N AS 03N BY EARLY MON.

$$
CHRISTENSEN