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Eastern Pacific Tropical Discussion

Active Tropical Systems Basin Outlooks Satellite
Eastern Pacific Basin Tropical Discussion
 
817 
AXPZ20 KNHC 200348
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SAT DEC 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH EXTENDS NW FROM THE PACIFIC COAST OF COLOMBIA  
AT 07N78W TO 10N85W TO 07N92W WHERE SCATTEROMETER WINDS INDICATE 
A TRANSITION TO AN ITCZ WHICH WIGGLES WESTWARD TO BEYOND 05N140W.
SCATTERED MODERATE CONVECTION IS OBSERVED S OF THE MONSOON TROUGH
WITHIN 30 NM EITHER SIDE OF A LINE FROM 05N77W TO 06N81W...ALONG 
THE ITCZ WITHIN 90 NM EITHER SIDE OF A LINE FROM 07N99W TO 
07N118W WHERE THE CONVECTION IS CURRENTLY INCRESING TO ISOLATED 
STRONG...AND ALONG THE ITCZ WITHIN 90 NM EITHER SIDE OF A LINE 
FROM 07.5N131W TO 07N135W.

...DISCUSSION...                                                 

AN UPPER LEVEL CONTINUES OVER THE CENTRAL PORTION OF THE   
DISCUSSION AREA WITH ITS MEAN AXIS CURRENTLY EXTENDING SW FROM 
32N111W ACROSS NORTHERN MEXICO TO A BASE OVER THE DEEP TROPICS 
AT 10N128W. UPPER MOISTURE IS SPREADING E ACROSS THE DISCUSSION 
AREA TO THE N OF 27N TO INCLUDE SOUTHERN CALIFORNIA...THE 
NORTHERN BAJA PENINSULA AND THE NORTHERN GULF OF CALIFORNIA. 
SCATTERED MODERATE CONVECTION IS ENHANCED E OF THE UPPER TROUGH 
WITHIN 120 NM OF A LINE FROM 10N129W TO 16N116W. A PLUME OF 
UPPER MOISTURE ORIGINATING WELL W OF THE DISCUSSION AREA STREAMS 
E ACROSS THE DISCUSSION AREA FROM 04-14N BETWEEN 140-125W...THEN 
TURNS NE IN RESPONSE TO THE UPPER TROUGH WITHIN ABOUT 330 NM 
EITHER SIDE OF A LINE FROM 10N125W TO 20N104W WHERE THE PLUME 
NARROWS AS IT CONTINUES NE ACROSS CENTRAL MEXICO AND THE CENTRAL 
GULF OF MEXICO AND ACROSS CENTRAL FLORIDA. DEBRIS MOISTURE FROM 
THE PREVIOUSLY DESCRIBED CONVECTIVE CLUSTERS E OF THE UPPER 
TROUGH IS RE-ENFORCING THE PLUME. 

AT THE LOW LEVELS LONG PERIOD NW SWELL CONTINUES TO MIX WITH  
LONG PERIOD SOUTHERLY SWELL ACROSS THE ENTIRE OPEN WATERS WATERS 
N OF THE ITCZ W OF 115W. A SURFACE RIDGE EXTENDS FROM 28N140W TO 
14N100W. NE 15-20 KT TRADES ARE OBSERVED ACROSS THE TROPICS 
BETWEEN THE ITCZ AND THE RIDGE WITH AN AREA OF EMBEDDED 20-25 KT 
NE WINDS ACROSS THE WATERS FROM 08-20N W OF 132W. THE GRADIENT 
SHOULD CONTINUE TO TIGHTEN OVER THE NEXT SEVERAL DAYS WITH THE 
20-25 KT CONDITIONS SPREADING E TO ALONG 120W. THE GRADIENT IS 
EXPECTED TO WEAKEN EARLY NEXT WEEK WITH THE TRADES RELAXING 
BELOW 20 KT LATE MON. 

A COLD FRONT IS WEAKENING AS IT PASSES E ACROSS THE DISCUSSION 
WATERS N OF THE RIDGE. ALTHOUGH ONLY A W-NW 10 KT WIND SHIFT IS 
OCCURRING ALONG THE FRONT...LARGE POST-FRONTAL NW SWELLS HAVE 
BUILT COMBINED SEAS UP TO 17 FT NEAR 30N135W. THIS LONG PERIOD 
NW SWELL WILL ARRIVE ALONG THE PACIFIC COAST OF THE BAJA 
PENINSULA IN THE FORM OF 8-13 FT SEAS ON SAT AFTERNOON...WITH 7-
10 FT SEAS EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE BAJA 
PENINSULA ON SUN. THE SWELLS WILL SUBSIDE WITH 6-8 FT CONDITIONS 
EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE BAJA PENINSULA ON 
MON AND MON NIGHT...THEN SUBSIDING TO 4-6 FT ON TUE ACROSS THE 
COASTAL WATERS S OF 28N.

GULF OF TEHUANTEPEC...EXPECTING A MAX OF 10-15 KT NOCTURNAL  
DRAINAGE FLOW ACROSS THE GULF OF TEHUANTEPEC TONIGHT AND 15-20 
KT ON SAT NIGHT. MODEL GUIDANCE SUGGESTS THE THE NEXT GALE EVENT 
WILL BEGIN AROUND SUNRISE ON WED INCREASING TO NEAR STORM 
STRENGTH ON WED NIGHT.
  
GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED THROUGH 
EARLY MON...THEN ONLY 10-15 KT DRAINAGE FLOW EARLY TUE.
  
GULF OF CALIFORNIA...15-25 KT NW WINDS ARE EXPECTED TONIGHT... 
THEN DIMINISH TO 15-20 KT ON SUN...FURTHER DIMINISHING TO 15 KT
ON MON. 
 
$$
NELSON