000
AXPZ20 KNHC 241525
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU OCT 24 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 
1445 UTC.

...SPECIAL FEATURES... 

AT 24/1500 UTC TROPICAL STORM RAYMOND IS CENTERED NEAR 14.8N 
105.9W MOVING W OR 270 DEGREES AT 8 KT. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 
KT WITH GUSTS TO 50 KT. NUMEROUS STRONG CONVECTION IS OBSERVED 
WITHIN 150 NM NE AND 45 NM SW SEMICIRCLES. RAYMOND IS EXPECTED 
TO MOVE WEST OR WEST-SOUTHWESTWARD FOR THE NEXT COUPLE OF DAYS.  
ATMOSPHERIC CONDITIONS MAY BECOME MORE CONDUCIVE TO ENABLE 
RAYMOND TO RE-INTENSIFY SOME OVER THE NEXT FEW DAYS AND THAT IS 
REFLECTED IN THE OFFICIAL FORECAST. SEE THE LATEST NHC PUBLIC 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP2/WTPZ32 KNHC...AND THE 
FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 
KNHC FOR MORE DETAILS ON RAYMOND.

THE FIRST GALE-FORCE EVENT OF THE SEASON IS TAKING PLACE ACROSS 
THE GULF OF TEHUANTEPEC. THIS TYPICALLY OCCURS IN MID-OCTOBER. 
THIS GAP WIND EVENT IS ASSOCIATED WITH A COLD SURGE BEHIND A 
COLD FRONT NOW MOVING SE ACROSS THE GULF OF MEXICO. NORTHERLY 
WINDS ARE CURRENTLY AT MINIMAL GALE FORCE OF 30-35 KT WITH SEAS 
OF 10-14 FT WITHIN 30 NM EITHER SIDE OF A LINE FROM THE NORTH 
CENTRAL GULF OF TEHUANTEPEC TO 15N95W TO 13.5N96W. THE NORTHERLY 
WINDS ARE EXPECTED TO REMAIN NEAR MINIMAL GALE FORCE THROUGH 
EARLY SAT MORNING THEN QUICKLY DIMINISH BELOW GALE FORCE. 
AFTERWARDS...WINDS WILL CONTINUE TO PULSE TO 25 KT LATE EACH 
NIGHT THROUGH TUE NIGHT. THE GFS MODEL SUGGESTS THAT WINDS COULD 
REACH 40 KT EARLY FRI MORNING WHILE THE NAM REGIONAL MODEL KEEPS 
THIS EVENT AT MINIMAL GALE FORCE WITH 35 KT. DECIDE TO INCREASE 
WINDS TO 40 KT BY EARLY FRI MORNING TAKING INTO ACCOUNT THAT 
WINDS ARE USUALLY GREATEST DURING THE OVERNIGHT AND EARLY 
MORNING HOURS WITH THE AID OF DRAINAGE FLOW.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
           
THE MONSOON TROUGH REMAINS SPLIT AS A RESULT OF TROPICAL STORM 
RAYMOND. IT EXTENDS FROM 09N85W TO 08N90W TO 12N98W...THEN 
CONTINUES FROM 11N107W TO 1009 MB LOW PRES NEAR 09N112W TO 
ANOTHER 1009 LOW PRES NEAR 09N126W TO 08N130W. ITCZ 08N130W TO 
10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
FROM 07N TO 09N BETWEEN 89W AND 93W...FROM 12N TO 14N BETWEEN 
95W AND 100W...AND WITHIN 100 NM SW SEMICIRCLE OF LOW PRES NEAR 
09N112W.

...DISCUSSION...                                             

A COLD FRONT HAS MOVED INTO THE NW PART OF THE FORECAST AREA. 
ALTHOUGH ASSOCIATED WINDS ARE FORECAST AT ONLY 15-20 KT ACROSS 
THE DISCUSSION WATERS NW OF THE FRONT...SEAS ARE EXPECTED TO 
BUILD TO NEAR 9 FT PRIMARILY IN NW SWELL NW OF FRONT EARLY FRI 
MORNING. THE FRONT IS EXPECTED TO WEAKEN TO A TROUGH SAT MORNING 
WITH ASSOCIATED SEAS SUBSIDING TO BELOW 8 FT. 

HIGH PRESSURE OF 1018 MB IS CENTERED OVER THE NORTH PART OF THE 
AREA NEAR 26N129W WITH ASSOCIATED RIDGE EXTENDING SE TO NEAR 
20N110W. THE PRESSURE GRADIENT BETWEEN THE RIDGE AND MONSOON 
TROUGH IS SUPPORTING MODERATE TO FRESH TRADES. SCATTEROMETER 
DATA CONFIRMED THE PRESENCE OF THESE WIND SPEEDS. SEAS TO 8 FT 
IS SEEN FROM 12N TO 16N W OF 136W PRIMARILY IN NW SWELL. THESE 
MARINE CONDITIONS WILL SHIFT W OF 140W LATER TODAY.

A PAIR OF WEAK LOW PRES CENTERS ARE NOTED ALONG THE MONSOON 
TROUGH. ONE IS NEAR 09N112W AND THE SECOND ONE IS NEAR 09N126W. 
BOTH ARE WELL DEFINED USING NIGHT CHANNEL VISIBLE IMAGERY. THESE 
SYSTEMS WILL DRIFT WWD.
 
$$
GR