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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 250334
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SUN JAN 25 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 
0300 UTC. 

...SPECIAL FEATURES...                                          
A GALE WARNING REMAINS IN EFFECT FOR THE GULF OF TEHUANTEPEC. N 
TO NE WINDS OF 30-40 KT ARE OCCURRING ACROSS THE REGION AS COLD 
DENSE AIR CONTINUES TO FUNNEL THROUGH THE CHIVELA PASS AND INTO 
THE GULF. MAX SEAS OF 14-16 FT ARE ASSOCIATED WITH THESE WIND 
SPEEDS. WINDS ARE FORECAST TO DIMINISH TO MINIMAL GALE FORCE SUN 
AFTERNOON AND EVENING...THEN INCREASE AGAIN TO 35-40 KT LATE SUN 
NIGHT INTO MON MORNING AS A REINFORCING PUSH OF COLD AIR OCCURS. 
THIS IS FORECAST TO BE A LONG DURATION GALE FORCE GAP WIND 
EVENT. NORTHERLY WINDS IN THE 35-40 KT RANGE ARE EXPECTED TO 
LIKELY PERSIST THROUGH WED MORNING AS HIGH PRES PERSISTS OVER 
THE WESTERN GULF THROUGH MID WEEK. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM 06N77W TO 04N83W TO 07N95W. THE 
ITCZ CONTINUES FROM 07N95W TO 08N110W TO 07N125W TO 06N140W. 
SCATTERED MODERATE CONVECTION IS FROM 02N TO 04.5N BETWEEN 83W 
AND 86W...AND FROM 10N TO 12N BETWEEN 107W AND 110W.

...DISCUSSION...                                                
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE FORECAST AREA 
W OF 100W. A STRONG CUT-OFF LOW HAS DEVELOPED JUST W OF BAJA 
CALIFORNIA AND IS CENTERED NEAR 27N117W. A TROUGH EXTENDS FROM 
THIS UPPER-LEVEL LOW S-SW TO NEAR 13N122W. ABUNDANT MIDDLE TO 
UPPER LEVEL MOISTURE IS STREAMING E-NE AHEAD OF THE TROUGH AXIS. 
AN ANTICYCLONE LOCATED OVER NORTHERN COLOMBIA AND WESTERN 
VENEZUELA EXTENDS A RIDGE ACROSS CENTRAL AMERICA AND SE MEXICO.

AT THE SURFACE...THE STRONG HIGH PRES THAT WAS LOCATED WELL N OF 
THE AREA DURING THE PREVIOUS DAYS IS WEAKENING AS A COLD FRONT 
APPROACHES FROM THE WEST. THIS HIGH PRES OF 1023 MB EXTENDS A 
RIDGE SOUTHWARD TO COVER MOST OF THE DISCUSSION AREA N OF 20N. A 
WEAK SURFACE TROUGH...FORMERLY ASSOCIATED WITH THE ABOVE 
MENTIONED UPPER LEVEL TROUGHING...EXTENDS FROM 19N137W TO 
12N139W. RECENT SCATTEROMETER DATA PROVIDED OBSERVATIONS OF 
MODERATE TO FRESH WINDS ACROSS THE SOUTHERN PERIPHERY OF THE 
RIDGE FROM 15N TO 25N W OF 120W. A NEW TROUGH IS ANALYZED FROM 
20N116W TO 11N118W AND IS GENERATING SOME SHOWERS AND TSTM 
ACTIVITY. A DIFFLUENT PATTERN ALOFT AHEAD OF THE AFOREMENTIONED 
UPPER-LEVEL TROUGH IS HELPING TO INDUCE THIS CONVECTIVE 
ACTIVITY. THIS TROUGH IS FORECAST TO DRIFT EASTWARD.

AN AREA OF LARGE LONG PERIOD NW SWELL...ASSOCIATED WITH A COLD 
FRONT IN THE CENTRAL PACIFIC NE OF HAWAII...IS PROPAGATING SE 
THROUGH THE WESTERN WATERS. THESE SWELLS ARE RESULTING IN MAX 
COMBINED SEAS OF 11-12 FT WITH PERIODS OF 16-18 SECONDS. THE 
COLD FRONT WILL ENTER THE FAR NW PORTION OF THE AREA AROUND 
25/1800 UTC AND EXTEND FROM 30N136W TO 23N140W BY 26/1800 UTC. 
FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED IN THE WAKE OF THE 
FRONT WITH BUILDING SEAS OF 9-11 FT. THE EXTENSIVE SWELL TRAIN 
ASSOCIATED WITH THIS FRONT WITH SEAS OF 8-11 FT WILL CONTINUE TO 
PROPAGATE ACROSS THE FORECAST WATERS REACHING THE AREA W OF A 
LINE FROM 30N120W TO 15N130W TO 07N135W BY 48 HOURS.

HIGH PRES OVER THE SOUTHWEST U.S. IN COMBINATION WITH A SURFACE 
TROUGH ACROSS NW MEXICO HAS TIGHTENED THE PRES GRADIENT IN THE 
GULF OF CALIFORNIA. WINDS ARE PRESENTLY FRESH TO STRONG FROM N 
OF 29N WITH SEAS LESS THAN 8 FT. THESE WINDS ARE EXPECTED TO 
DIMINISH TO 20 KT OR LESS BY LATE TONIGHT INTO EARLY SUN. 

GAP WINDS...                                                
FRESH TO LOCALLY STRONG WINDS ARE EXPECTED TO INCREASE TO 25 KT 
TONIGHT AND INTO SUN MORNING THROUGH THE GULF OF PAPAGAYO AS 
HIGH PRES BUILDS ACROSS THE WESTERN CARIBBEAN. THESE WINDS ARE 
FORECAST TO LAST THROUGH MON NIGHT INTO TUE MORNING. AT THAT 
TIME...MARINE GUIDANCE ALSO SUGGESTS INCREASING WINDS ACROSS THE 
GULF OF FONSECA.

FRESH TO STRONG NORTHERLY WINDS ARE ALSO EXPECTED THROUGH THE 
GULF OF PANAMA TONIGHT AND INTO SUN MORNING REACHING 25 KT N OF 
05N BETWEEN 79W AND 81W. 

THE PRES GRADIENT WILL REMAIN STRONG ENOUGH ACROSS THE WESTERN 
CARIBBEAN THROUGH AT LEAST TUE TO SUPPORT ALL THESE GAP WIND 
EVENTS. 

$$ 
GR



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Page last modified: Sunday, 25-Jan-2015 03:35:05 UTC