000
AXPZ20 KNHC 190244
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC MON OCT 19 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.               

...SPECIAL FEATURES...

HURRICANE OLAF IS CENTERED NEAR 9.7N 135.4W AT 0300 UTC MOVING 
WEST OR 275 DEGREES AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 
IS 978 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS 
TO 105 KT. NUMEROUS MODERATE TO STRONG CONVECTION WAS NOTED 
WITHIN 60 NM OF CENTER. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED ELSEWHERE FROM 04N TO 12N BETWEEN 130W AND 
138W. SCATTERED MODERATE ISOLATE STRONG CONVECTION WAS NOTED 
WITHIN 30 NM OF LINE 13N124W TO 14N127W TO 14N131W TO 13N134W. 
OLAF IS FORECAST TO CONTINUE TO INTENSIFY OVER THE NEXT COUPLE 
OF DAYS AS IT MOVES W-NW ACROSS WARM WATERS AND THROUGH A 
GENERALLY LOW SHEAR ENVIRONMENT. OLAF IS EXPECTED TO REACH MAJOR 
HURRICANE INTENSITY ON MON. PLEASE SEE LATEST FORECAST ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS 
ON OLAF. 

GULF OF TEHUANTEPEC...EARLIER SCATTEROMETER PASS INDICATES THAT 
WINDS HAVE DIMINISHED BELOW GALE FORCE. LOW PRESSURE HAS FORMED 
AS A RESULT OF THE INTERACTION OF THE GALE FORCE GAP WIND EVENT 
AND THE MONSOON TROUGH. THIS LOW PRESSURE AREA IS EMBEDDED IN A 
LARGER SCALE CENTRAL AMERICAN GYRE. ABUNDANT TROPICAL MOISTURE 
REMAINS AROUND THE NORTHERN PART OF CENTRAL AMERICA AND SOUTHERN 
MEXICO ASSOCIATED TO THIS GYRE WILL KEEP THE POTENTIAL FOR 
ACTIVE WEATHER OVER THIS AREA FOR THE NEXT COUPLE OF DAYS. 
GLOBAL MODELS CONTINUE TO SUGGEST THE LOW COULD DEVELOP INTO A 
TROPICAL CYCLONE AROUND MID-WEEK AND THERE IS CURRENTLY A MEDIUM 
CHANCE FOR TROPICAL CYCLOGENESIS WITHIN THE NEXT 48 HOURS. 
REGARDLESS OF TROPICAL CYCLONE FORMATION...THIS SYNOPTIC SETUP 
WILL CONTINUE TO BRING THE POTENTIAL FOR LOCALLY HEAVY RAINFALL 
WHICH MAY LEAD TO FLASH FLOODING AND DANGEROUS MUDSLIDES OVER 
PORTIONS OF CENTRAL AMERICA AND SOUTHEASTERN MEXICO OVER THE 
NEXT COUPLE OF DAYS. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH EXTENDS FROM 15N93W TO LOW PRES NEAR 12N95W 
TO LOW PRES NEAR 08N119W TO 09N123W. NUMEROUS MODERATE TO STRONG 
CONVECTION WAS NOTED OVER WATERS N OF 13N BETWEEN 95W AND 100W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED OVER 
FORECAST WATERS N OF 11N BETWEEN 88W AND 94W.

...DISCUSSION... 

HIGH PRESSURE OF 1025 MB CENTERED NEAR 34N140W EXTENDS A RIDGE 
SE TO NEAR 21N112W. THE BUILDING HIGH PRESSURE HAS HELPED EXPAND 
20-33 KT WINDS OVER THE NORTHERN PART OF OLAF. OUTSIDE OF THE 
CIRCULATION ASSOCIATED TO OLAF...GENTLE TO MODERATE TRADE WINDS 
PREVAIL OVER MUCH OF THE WESTERN PORTION OF THE DISCUSSION AREA. 
THE RIDGE WILL STRENGTHEN THROUGH TUE...AND HELP TO EXPAND THE 
AREA OF 20-33 KT WINDS N OF OLAF. 

LONG PERIOD SW SWELL WITH PERIODS IN THE 18-20 SECOND RANGE IS 
CURRENTLY AFFECTING THE COAST ALONG CENTRAL AMERICA AND 
NORTHWARD TO THE COAST OF MEXICO...INCLUDING AS FAR NORTH AS THE 
BAJA CALIFORNIA PENINSULA. THIS LONG-PERIOD SWELL COULD MAKE FOR 
DANGEROUS CONDITIONS ENTERING AND EXITING PORTS AND WILL 
INCREASE THE THREAT OF RIP CURRENTS. 

$$ 
AL