000
AXPZ20 KNHC 160955
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1005 UTC MON SEP 16 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
            
THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 14N90W...THEN 
RESUMES FROM 14N107W TO 08N120W TO 07N137W. ITCZ AXIS EXTENDS 
FROM FROM 07N137W TO 07N140W. SCATTERED MODERATE CONVECTION IS 
NOTED WITHIN 90 NM S OF AXIS BETWEEN 85W AND 90W.

...DISCUSSION...

THE TROPICAL CYCLONE THAT WAS MANUEL HAS BEEN DOWNGRADED TO A 
POST TROPICAL REMNANT AREA OF LOW PRES...CENTERED INLAND OVER 
THE MOUNTAINOUS TERRAIN OF JALISCO NEAR 20.6N 105.3W AT 
16/0900Z. ESTIMATED PRES IS 1002 MB WITH MOVEMENT TO THE NW AT 7 
KT. A LARGE AREA OF CONVECTION ACCOMPANIES THE TRACK OF THIS LOW 
WITHIN 90 NM OFFSHORE...ASSOCIATED WITH THE EASTERLY FLOW ON THE 
N SIDE OF THE PRES CONVERGING WITH THE MODERATE TO FRESH W TO NW 
FLOW MOVING ONSHORE. MUCH OF THIS CONVECTION WILL START TO 
WEAKEN LATER THIS MORNING...IN PART DUE TO NORMAL DIURNAL TRENDS 
BUT ALSO BECAUSE THE LOW PRES IS EXPECTED TO DISSIPATE LATER 
TODAY AS IT DRIFTS NW AND MOVES OFFSHORE. 

THE OVERALL SEA LEVEL PRES REMAINS VERY LOW ALONG THE NW COAST 
OF MEXICO. WHILE TROPICAL CYCLONE FORMATION IS NOT 
EXPECTED...GLOBAL MODELS SUGGEST THERE WILL BE SPURIOUS LOW PRES 
AREAS BETWEEN THE SOUTHERN TIP OF THE BAJA PENINSULA AND CABO 
CORRIENTES OVER THE NEXT COUPLE OF DAYS...AT THE BASE OF A SHARP 
LOW TO MID LEVEL TROUGH EXTENDING ROUGHLY DOWN THE LENGTH OF THE 
GULF OF CALIFORNIA. IN THE MID TO UPPER LEVELS...A SHARP TROUGH 
THAT REACHED FROM THE GREAT BASIN ACROSS THE SOUTHERN ROCKIES 
AND NW MEXICO TO THE SOUTHERN GULF OF CALIFORNIA IS WEAKENING. 
THIS TROUGH HAD BEEN PROVIDING CONSIDERABLE UPPER SUPPORT TO THE 
CONVECTION E OF 105W ASSOCIATED WITH MANUEL OVER THE PAST COUPLE 
OF DAYS. WEAK LOWER TO MID LEVEL TROUGH IS EXPECTED TO REMAIN IN 
PLACE OVER THIS AREA THROUGH MID WEEK...ENHANCING COASTAL 
CONVECTION MAINLY AT NIGHT.

ASCAT PASSES FROM THE PAST SEVERAL HOURS INDICATED THE SURGE OF 
FRESH TO STRONG SW FLOW WITHIN 240 NM S OF THE MONSOON TROUGH 
BETWEEN 100W TO 110W. CONCURRENT ALTIMETER PASSES INDICATES SEAS 
IN EXCESS OF 11 FT WITH HIGHEST SEAS ESTIMATED AROUND 13 FT NEAR 
THE COAST. THE WINDS AND SEAS WILL GRADUALLY DIMINISH AS THE 
OVERALL MONSOON GYRE WEAKENS AND REORIENTS ITSELF WESTWARD. 
DESPITE THE WEAKENING TREND...THE STRONG SW FLOW WILL CONTINUE 
TO POSE A RISK OF DANGEROUS SURF AND RIP CURRENTS ALONG COASTAL 
AREAS FROM WESTERN OAXACA TO MICHOACAN THROUGH TODAY. RAINFALL 
WILL ALSO CONTINUE TO BE AN ISSUE AS MOIST ONSHORE FLOW PUSHES 
INTO THE COASTAL MTNS...PROLONGING THE RISK OF 
ISOLATED AREAS OF FLOODING AND MUDSLIDES. 

CLUSTERS OF STRONG SHOWERS AND THUNDERSTORMS ARE ACTIVE ALONG 
THE COASTS OF PANAMA AND COSTA RICA...WHERE OVERNIGHT DRAINAGE 
FLOW IS CONVERGING WITH LIGHT TO MODERATE SW FLOW. 

FARTHER WEST...1027 MB HIGH PRES IS CENTERED NEAR 37N153W WITH A 
RIDGE EXTENDING W TO THE COAST OF BAJA CALIFORNIA NORTE. ASCAT 
DATA FROM 04 UTC INDICATED 15 TO 20 KT NW FLOW ALONG THE COAST 
OF THE BAJA PENINSULA AND S OF THE SOUTHERN TIP OF THE PENINSULA 
TO 15N...BETWEEN THE TROUGH OVER NW MEXICO AND RIDGE.

ELSEWHERE...LIGHT TO MODERATE WINDS AND SLIGHT SEAS PREVAIL WITH 
NO SIGNIFICANT CONVECTION NOTED.
 
$$
CHRISTENSEN