000
AXPZ20 KNHC 231533
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED APR 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH IS ILL-DEFINED. THE ITCZ AXIS EXTENDS FROM 
04N95W TO 04N110W TO 06N125W TO 04N140W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS NOTED FROM 06N TO 10N BETWEEN 116W 
AND 120W...FROM 04N TO 10N BETWEEN 120W AND 130W AND FROM 02N TO 
04N BETWEEN 132W AND 135W. 

...DISCUSSION...                                       

ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM 31N112W TO 21N124W. 
THIS TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM 31N114W TO 
28N118W. FRESH TO STRONG WINDS FOLLOW THE FRONT WITH SEAS TO 11 
FT IN NW SWELL. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THE 
FRONT WHICH IS FORECAST TO DISSIPATE ACROSS THE FAR NE WATERS 
LATER TODAY. AN UPPER LEVEL RIDGE IS W OF THE TROUGH WITH AXIS 
NEAR 140W AND DOMINATES THE NW PART OF THE FORECAST AREA... 
MAINLY N OF 20N W OF 130W. A BROAD UPPER LEVEL RIDGE IS E OF THE 
TROUGH ACROSS NORTHERN MEXICO. MODERATE TO STRONG MID TO UPPER 
LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED ON WATER 
VAPOR IMAGERY N OF 16N W OF 130W AND ALONG THE TROUGH AXIS. IN 
THE DEEP TROPICS...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS 
CENTERED NEAR 9N127W. UPPER DIFFLUENT ASSOCIATED WITH THIS 
SYSTEM IS HELPING TO INDUCE THE CONVECTIVE ACTIVITY BETWEEN 116W 
AND 128W. A SHORT-WAVE TROUGH IS ACROSS THE ISTHMUS OF 
TEHUANTEPEC TO NEAR 12N85W. A RIDGE FROM NORTHERN SOUTH AMERICA 
EXTENDS WESTWARD COVERING MOST OF CENTRAL AMERICA. 

A 1028 MB HIGH PRES LOCATED NEAR 32N142W EXTENDS A RIDGE SE 
ACROSS THE FORECAST WATERS TO NEAR 20N115W. FRESH TO STRONG NE 
TO E TRADE WINDS ARE NOTED PER SCATTEROMETER DATA ON THE 
SOUTHERN PERIPHERY OF THE RIDGE AND N OF THE ITCZ AXIS... 
PARTICULARLY FROM 10N TO 20N W OF 130W AND FROM 11N TO 17N 
BETWEEN 124W AND 130W. THE AERIAL EXTENT AND STRENGTH OF THE 
TRADES WILL DECREASE ON THU AS HIGH PRES MOVES EASTWARD AND 
DISSIPATES. WINDS OF 20-25 KT ARE ALSO NOTED JUST OFF OF 
NORTHERN BAJA CALIFORNIA DUE A TIGHT PRES GRADIENT BETWEEN A LOW 
CENTER OVER ARIZONA AND THE HIGH PRES. THESE WINDS ARE EXPECTED 
TO DIMINISH TO 20 KT OR LESS IN ABOUT 24 HOURS.
 
LONG PERIOD NW SWELLS...WITH A LEADING EDGE PERIOD OF 17-18 
SECONDS WILL MIX WITH SHORTER PERIOD NE SWELL FROM THE TRADE 
WIND FLOW AND CROSS EQUATORIAL S SWELL TO GENERATE A LARGE AREA 
OF 8 TO 10 FT SEAS AFFECTING MAINLY THE WATERS E OF 130W AND S 
OF LINE FROM 13N130W TO 10N110W TO 3.4S90W BY THU MORNING...AND 
E OF 125W AND S OF LINE FROM 15N125W TO 17N110W TO 05N92W BY FRI 
MORNING. EXPECT ALSO BUILDING SEAS TO 8 FT E OF THE GALAPAGOS 
ISLANDS TO ABOUT 2N.  BASED ON WAVE WATCH GUIDANCE...THIS SWELL 
EVENT IS FORECAST TO REACH THE MEXICAN COAST E OF 110W THU 
NIGHT...AND THE SOUTH PORTION OF THE GULF OF CALIFORNIA OR SEA 
OF CORTEZ EARLY ON FRI...BRINGING ROUGH SURF CONDITIONS TO THOSE 
COAST.

WINDS ARE EXPECTED TO PULSE TO 15-20 KT ACROSS THE GULF OF 
PAPAGAYO DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE 
ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW THROUGH THE FORECAST 
PERIOD.   

$$ 
GR