000
AXPZ20 KNHC 031537
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN NOV 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...    

TROPICAL STORM SONIA WAS CENTERED NEAR 19.9N 109.8W AT 03/1500 
UTC MOVING N AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 
1003 MB. WITH VERTICAL WIND SHEAR RELAXING SLIGHTLY...SONIA HAS 
INTENSIFIED WITH MAXIMUM SUSTAINED WIND SPEED OF 40 KT WITH 
GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS ON 
SONIA. NUMEROUS MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 
210 NM NW SEMICIRCLE. THE OFFICIAL FORECAST CALLS FOR WINDS TO 
REMAIN NEAR 40 KT THROUGH THE NEXT 24 HOURS...THEN AN INCREASE 
IN VERTICAL WIND SHEAR WILL CAUSE SONIA TO WEAKEN TO MINIMAL 
TROPICAL STORM FORCE AS IT APPROACHES LANDFALL. DANGEROUS SURF 
WILL IMPACT THE SOUTHERN PORTION OF BAJA CALIFORNIA 
SUR...SPREADING INTO THE SOUTHERN GULF OF CALIFORNIA AND 
IMPACTING THE W CENTRAL COAST OF MEXICO LATER TODAY INTO EARLY 
NEXT WEEK. THIS SYSTEM WILL BRING THE CHANCE FOR HEAVY RAINFALL 
OVER THE SOUTHERN PORTION OF BAJA CALIFORNIA SUR AND THE STATES 
OF SINALOA...DURANGO AND SOUTHERN CHIHUAHUA OVER THE NEXT 24-48 
HOURS. THESE HEAVY RAINS WILL CREATE THE POSSIBILITY FOR 
DANGEROUS FLASH FLOODS AND MUDSLIDES.

GULF OF TEHUANTEPEC...WINDS OF 30-40 KT PREVAIL OVER THE GULF OF 
TEHUANTEPEC WITHIN 45 NM EITHER SIDE OF A LINE FROM 16N95W TO 
15N95W TO 13.5N96.5W. THE STRONG PUSH OF COOL AIR FROM THE GULF 
OF MEXICO WILL DECREASE TODAY AS WINDS VEER. THIS WILL BRING A 
DECREASE IN WINDS FUNNELING THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC...AND WINDS ARE EXPECTED TO DIMINISH BELOW 
GALE FORCE LATE TONIGHT. WINDS WILL FURTHER DECREASE MON...AND 
BY MON AFTERNOON WINDS AND SEAS ARE EXPECTED TO BE BELOW 
ADVISORY CRITERIA. 

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

THE MONSOON TROUGH EXTENDS FROM 10N86W TO 1010 MB LOW PRES NEAR 
09N93W TO 12N97W. IT RESUMES FROM 16N115W TO 1011 MB LOW PRES 
NEAR 14N121W TO 10N130W WHERE LOW LEVEL WINDS SUGGEST A 
TRANSITION TO ITCZ WHICH EXTENDS TO BEYOND 09N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WAS NOTED FROM 11N TO 16N 
BETWEEN 94W AND 102W.

...DISCUSSION...    

HIGH PRESSURE OF 1034 MB IS CENTERED WELL NW OF THE AREA NEAR 
40N143W WITH A WEAK COLD FRONT OVER THE FAR N PART OF THE 
FORECAST AREA. THE DISTANCE OF THE HIGH PRESSURE CENTER FROM THE 
AREA IS KEEPING THE PRESSURE GRADIENT LOOSE ENOUGH WHERE TRADES 
ARE 20 KT OR LESS. GALE FORCE WINDS N OF THE AREA OFF THE 
CALIFORNIA COAST WILL GENERATE NORTHERLY SWELLS WHICH WILL 
PROPAGATE INTO THE FORECAST AREA THIS AFTERNOON. SEAS OVER THE 
FAR N PART OF THE FORECAST AREA WILL CONTINUE TO BUILD... 
REACHING NEAR 11 FT BY MON MORNING. THE SWELL WILL CONTINUE TO 
PUSH SOUTHWARD OVER THE FORECAST AREA WITH SEAS IN THE 8-11 FT 
RANGE COVERING THE AREA N OF A LINE FROM 20N140W TO 20N132W TO 
25N117W BY TUE MORNING.

$$
AL