000
AXPZ20 KNHC 182224 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED DEC 18 2013

CORRECTED SURFACE AND PAPAGAYO SECTIONS

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2200 UTC.

...SPECIAL FEATURE...
 
GULF OF TEHUANTEPEC...THE 1620 UTC ASCAT PASS CLEARLY DEPICTED A 
SWATH OF N TO NE GALE FORCE WINDS OF 30-35 KT WITHIN THROUGH THE 
GULF WITHIN ABOUT 30-45 NM OF A LINE FROM 16N95W TO NEAR 14N96W. 
WITH THE CULPRIT TIGHT PRES GRADIENT OVER SOUTHEASTERN MEXICO 
EXPECTED TO SLACKEN THROUGH THE NEXT 12-18 HRS...THESE WINDS 
WILL RESPOND BY DIMINISHING TO 20-30 KT TONIGHT...AND INTO EARLY 
THU AND TO 15-20 KT BY THU AFTERNOON BEFORE DIMINISHING FURTHER 
TO 10-15 KT THU EVENING AND FRI. SEAS OF 10-14 FT IN THE GULF 
WILL SUBSIDE TO 8-10 FT BY EARLY THU...AND TO 9 FT IN MIXED 
SWELL BY THU AFTERNOON. SEAS DOWNSTREAM FROM THE GULF WILL ALSO 
SUBSIDE TO AROUND 9 FT IN MIXED SWELL WITHIN THE AREA BOUNDED BY 
A LINE FROM 15N95W TO 07N98W TO 10N107W TO 15N95W BY THU 
AFTERNOON. BY THU EVENING...SEAS ARE EXPECTED TO BE BELOW 8 FT 
IN THE GULF WITH SEAS LESS THAN 8 FT.

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

THE MONSOON TROUGH AXIS EXTENDS FROM THE COLOMBIAN COAST AT 
07N78W TO 07N86W TO 07N100W...WHERE LOW LEVEL WINDS SUGGEST IT 
TRANSITIONS TO THE ITCZ TO 07N111W TO 08N130W TO 07N140W. 
SCATTERED/MODERATE ISOLATED STRONG IS WITHIN 180 NM S OF THE OF 
ITCZ BETWEEN 119W-124W. SCATTERED MODERATE CONVECTION IS WITHIN 
120 NM N OF THE ITCZ BETWEEN 127W-132W...AND ALSO WITHIN 90 NM S 
OF MONSOON TROUGH E OF 81W.
  
...DISCUSSION... 

ALOFT...                                                       
AN ANTICYCLONE IS SEEN NEAR 12N117W WITH ITS ASSOCIATED BROAD 
ANTICYCLONIC ENVELOP COVERING THE AREA FROM 11N TO 26N W OF 
109W. A NARROW UPPER TROUGH IS E OF THE ANTICYCLONIC FLOW ALONG 
108W WITH AN ASSOCIATED SMALL CYCLONIC CIRCULATION AT 13N108W.  
A SMALL ANTICYCLONE IS E OF THIS TROUGH NEAR 12N99W...WHILE A 
CYCLONIC CIRCULATION IS TO ITS SE NEAR 06N95W. OVER THE NRN 
PORTION OF THE AREA...AN UPPER TROUGH WITH SHORTWAVE ENERGY 
MOVING THROUGH IT IS RAPIDLY SWEEPING SEWD JUST N OF THE AREA 
ALONG 32N33N. A JET STREAM BRANCH BETWEEN IT AND THE 
ANTICYCLONIC RIDGE CREST TO ITS S IS ACCOMPANIED BY MODERATE SW 
WINDS THAT ARE TRANSPORTING ABUNDANT BROKEN MID/HIGH CLOUDS NEWD 
BETWEEN 110W-122W AND FROM 11N-23N W OF 122W. DIFFLUENT FLOW SE 
OF THE ANTICYCLONE IS AIDING THE ACTIVE CONVECTION DESCRIBED 
ABOVE WITH THE ITCZ AXIS. SATELLITE WATER VAPOR IMAGERY SHOWS 
MOSTLY MODERATE SUBSIDENCE ELSEWHERE KEEPING GENERALLY DRY AND 
STABLE ATMOSPHERIC CONDITIONS...EXCEPT FOR W OF THE ANTICYCLONE 
WHERE SLY UPPER FLOW THERE IS ADVECTING THE DEBRIS MOISTURE N 
AND NE AROUND THE AFOREMENTIONED ANTICYCLONIC FLOW AND 
CONTRIBUTING TO THE ATMOSPHERIC MOISTURE DESCRIBED ABOVE. THIS 
MOISTURE IS SEEN IN THE FORM OF THE SCATTERED TO BROKEN HIGH 
CLOUDS. THE MOISTURE...HOWEVER...ERODES IN THE DRY AIR ONCE IT 
REACHES NEAR 110W. 

SURFACE...                                                       
A SURFACE RIDGE ANCHORED BY A 1033 MB ANTICYCLONE CENTER NW OF 
THE AREA NEAR 37N144W EXTENDS SEWD THROUGH 32N137W AND TO NEAR 
21N122W. ASCAT DATA FROM 1800 UTC THIS AFTERNOON REVEALED FRESH 
NE TRADES S OF THE RIDGE AND N OF THE ITCZ W OF 128W. LONG 
PERIOD NW SWELLS ARE MIXING WITH THE NE TRADE WIND SWELL AND 
ALSO LONG PERIOD CROSS-EQUATORIAL SOUTHERLY SWELL...RESULTING IN 
COMBINED SEAS OF ABOUT 9 FT WITHIN THE AREA OF ENHANCED TRADES. 
BY THU AFTERNOON...NE WINDS OF 20-25 KT ARE EXPECTED FROM 10N TO 
20N W OF 133W WITH SEAS TO 9 FT. ELSEWHERE FROM 09N TO 29N W OF 
132W WINDS OF 20 KT OR LESS ARE FORECAST WITH SEAS 8 FT IN MIXED 
NE AND NW SWELL. BY FRI AFTERNOON...NE WINDS OF 20-25 KT ARE 
FORECAST FROM 10N TO 26N W OF 135W WITH SEAS TO 9 FT. THE UPPER 
TROUGH DESCRIBED ABOVE UNDER ALOFT WILL DRIVE A COLD FRONT SEWD 
TO ALONG A POSITION FROM NEAR 31N118W TO 26N127W BY THU 
AFTERNOON. THE PARENT LOW PRES WILL BE NEAR 32N113W 1004 MB WITH 
THE DISSIPATING COLD FRONT FROM LOW TO 30N114W TO 26N115W TO 
23N127W BY FRI AFTERNOON. NW TO N WINDS OF 20-25 KT ARE EXPECTED 
N OF THE FRONT THU WITH SEAS 8-11 FT. ON FRI...N TO NE WINDS OF 
20-25 KT ARE FORECAST N OF 23N BETWEEN 125W AND 135W WITH SEAS 
LARGE SEAS OF 10-16 FT IN N TO NE SWELLS.
 
GULF OF PAPAGAYO...NE-E WINDS WILL PULSE AT 20-25 KT DURING MAX 
NOCTURNAL DRAINAGE PERIOD TONIGHT THROUGH EARLY THU 
EVENING...THEN DIMINISH TO 15-20 KT THU NIGHT. WINDS THEN 
INCREASE AGAIN TO 20-25 KT LATE THU NIGHT INTO EARLY FRI AND 
DIMINISH TO 15-20 KT FRI IN THE AFTERNOON. NE SWELLS PROPAGATING 
SW FROM THE GULF OF PAPAGAYO WILL MIX WITH SW SWELLS WITHIN 60 
NM OF A LINE FROM 09N90W TO 08N94W TO 07N98W IN 24 HRS WITH SEAS 
TO 9 FT. BY FRI AFTERNOON...SEAS ARE FORECAST TO BE LESS THAN 8 
FT IN...AND IN THE VICINITY OF THE GULF.

GULF OF CALIFORNIA...MODERATE TO FRESH NW WINDS WILL DIMINISH TO 
5-10 KT WED AND BECOME SOUTHERLY WED NIGHT. WINDS WILL INCREASE 
TO 20-25 KT OVER THE NORTHERN GULF EARLY THU EVENING THEN 
DIMINISH BY FRI AFTERNOON.

$$ 
AGUIRRE