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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 212143
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC FRI NOV 21 2014

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 
2115 UTC.                       

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
MONSOON TROUGH AXIS EXTENDS FROM 9N83W ALONG 10N91W TO 1010 MB 
LOW NEAR 9N97W ALONG 7N101W TO 1009 MB LOW NEAR 11N118W TO 
7N124W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 9N133W TO 
8N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM 
N AND 90 NM S OF MONSOON TROUGH BETWEEN 92W-95W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF 
MONSOON TROUGH BETWEEN 86W-92W...WITHIN 210 NM S OF MONSOON 
TROUGH BETWEEN 115W-120W...AND WITHIN 75 NM OF THE ITCZ W OF 
137W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF 
MONSOON TROUGH BETWEEN 100W-105W...WITHIN 120 NM N OF MONSOON 
TROUGH BETWEEN 104W-106W...AND WITHIN 150 NM N OF ITCZ BETWEEN 
127W-130W.  

...DISCUSSION...                                                 

ALOFT...AN UPPER-LEVEL TROUGH IS SHIFTING EASTWARD EXTENDING SW 
FROM AN UPPER LOW OVER ARIZONA ACROSS N BAJA CALIFORNIA TO NEAR 
20N120W. AN UPPER RIDGE IS ANCHORED NEAR 30N138W WITH A RIDGE 
AXIS STRETCHING SE IN THE WAKE OF THE TROUGH TO NEAR 25N126W. AS 
A RESULT...FLOW INTO THE BASE OF THE TROUGH IS BRINGING 
SUBSIDENT CONDITIONS WITH RELATED DRY AND STABLE AIR ACROSS THE 
AREA N OF 19N. S OF 19N THE ATMOSPHERE REMAINS VERY MOIST WITH 
ASSOCIATED ACTIVE CONVECTION ALONG AND NEAR THE ITCZ AND MONSOON 
TROUGH AS DESCRIBED ABOVE. 

AT THE SURFACE...A RIDGE EXTENDS FROM A 1026 MB HIGH LOCATED 
NEAR 30N140W WITH A RIDGE AXIS EXTENDING SE TO 22N115W. THE 
PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE AND LOWER PRESSURE 
IN THE VICINITY OF THE ITCZ IS INDUCING AN AREA OF FRESH TO 
STRONG TRADE WINDS OVER THE AREA DESCRIBED FROM 9N-25N W OF 
134W. THESE WINDS WILL EXPAND NORTHWARD AND SLIGHTLY EASTWARD 
THROUGH EARLY SAT AS HIGH LIFTS NORTHWARD WITH THE ASSOCIATED 
RIDGE BUILDING MORE FIRMLY S-SE OVER THE AREA. THESE WINDS THEN 
DIMINISH EARLY ON SUN AS THE HIGH AND RIDGE WEAKEN. BY SUN 
EVENING MOST OF THE AREA W OF 115W WILL HAVE SEAS OF 8 FT OR 
GREATER. 

A SURFACE TROUGH IS ANALYZED FROM 14N115W TO THE 1009 MB LOW 
NEAR 11N118W GENERATING SCATTERED MODERATE TO STRONG CONVECTION 
FROM 13N-15N BETWEEN 112W-115W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 11N-16N 
BETWEEN 107W-115W. THIS TROUGH AND LOW WILL MOVE WESTWARD WITH 
THE LOW DISSIPATING IN 36 TO 48 HOURS. THE WINDS AND SEAS WILL 
BECOME INTERMIXED WITH THE TRADE WINDS ABOVE.  

LONG PERIOD NW SWELL IS MOVING THROUGH THE CENTRAL PORTION OF 
THE AREA WITH A SECOND SURGE MOVING INTO THE NW PORTION OF THE 
AREA W OF 124W. THESE SWELLS WILL CONTINUE SE MERGING WITH A S 
SWELL EXPECTED TO MOVE ACROSS THE EQUATOR SAT AFTERNOON AS A 
THIRD SWELL EVENT MOVES INTO THE NW SECTION. THIS WILL KEEP MOST 
OF THE BASIN IN THE 14 TO 16 SEC PERIOD THROUGH THE WEEKEND. 

LOOKING FURTHER AHEAD...THE NEXT GULF OF TEHUANTEPEC IS FORECAST 
TO BE A STRONGER ONE. SOME MODELS SUGGEST THAT WINDS MAY 
POSSIBLY REACH MINIMAL STORM FORCE BY EARLY ON WED MORNING.  
WAVEWATCH GUIDANCE SUGGESTS BUILDING SEAS UP TO 20-24 FT WITH 
THIS EVENT. EDITS WILL BE MADE TO THE NDFD GRIDS AS NECESSARY 
PRIOR TO THIS UPCOMING EVENT.

$$
PAW



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Page last modified: Friday, 21-Nov-2014 21:43:52 UTC