000
AXPZ20 KNHC 211612
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                          
1605 UTC TUE JAN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.                              

...SPECIAL FEATURE...                                           
GULF OF TEHUANTEPEC GALE WARNING...NORTHERLY WINDS IN GULF OF 
TEHUANTEPEC HAVE INCREASED TO NEAR 20 KT THIS MORNING. STRONG 
HIGH PRESSURE BUILDING SOUTHWARD BEHIND A COLD FRONT INTO 
SOUTHERN MEXICO WILL BRING ANOTHER GALE FORCE GAP WIND EVENT TO 
THE GULF OF TEHUANTEPEC AFTER 18Z THIS AFTERNOON...WITH WINDS 
RAPIDLY INCREASING TO 40-45 KT THROUGH THIS EVENING. WITH THE 
ADDED COMPONENT OF NOCTURNAL DRAINAGE FLOW OVERNIGHT...WINDS MAY 
BRIEFLY REACH NEAR STORM FORCE EARLY WED. WINDS WILL DROP BELOW 
GALE WED NIGHT AND RAPIDLY DIMINISH AFTERWARDS THROUGH THU 
NIGHT. SEAS WILL QUICKLY BUILD TO 20 FT TONIGHT AND SEND A PLUME 
OF 8-13 FT NE SWELL DOWNWIND FROM THE REGION WED AND WED NIGHT. 
YET ANOTHER STRONG GALE OR POSSIBLE STORM GAP WIND EVENT IS 
EXPECTED TO BEGIN FRI MORNING.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
A VERY WEAK MONSOON TROUGH EXTENDS FROM 07N75W TO 09.5N85W TO 
06N89W WHERE IT TERMINATES. THE ITCZ EXTENDS FROM 03N94.5W TO 
07N118W TO  BEYOND 06.5N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION NOTED FROM 02N TO 07N E OF 79W. SCATTERED MODERATE TO 
STRONG CONVECTION NOTED WITHIN 360 NM N OF AXIS BETWEEN 122W AND 
140W. SCATTERED MODERATE CONVECTION NOTED FROM 14N TO 20N 
BETWEEN 132W AND 138W.

...DISCUSSION...          
WEAK HIGH PRESSURE RIDGE PREVAILS ACROSS THE NORTHERN WATERS N 
OF 15N BETWEEN 105W AND 142W. A VERY SHARP UPPER LEVEL TROUGH 
EXTENDING NEARLY N TO S ALONG 135W WITH BASE BETWEEN 5-15N WAS 
INDUCING SIGNIFICANT MIDDLE LEVEL LIFT AND UPPER LEVEL 
DIVERGENCE ACROSS AND TO THE N OF THE ITCZ...E OF THE TROUGH TO 
NEAR 120W...AND AIDING IN PRODUCING A BROAD AREA OF MULTI-
LAYERED CLOUDS AND EMBEDDED CONVECTION MENTIONED ABOVE W OF 
122W. ISOLATED TO SCATTERED MODERATE CONVECTION...SOME OCCURRING 
ALOFT...WAS WITHIN THE TROUGH FARTHER NW...AND MENTIONED 
ABOVE...BETWEEN 132W AND 138W. ALTHOUGH THE PRESSURE GRADIENT 
BETWEEN A 1024 MB HIGH N OF THE AREA AND THE ITCZ IS MODEST AT 
BEST...INSTABILITY IN THIS REGION IS ALLOWING FOR TRADES TO 
PROVIDE INFLOW INTO THIS CONVECTION AT AROUND 20 KT AND HIGHER. 
ELSEWHERE N OF THE ITCZ...MODERATE NE TO E TRADES OF 10-20 KT 
GENERALLY PREVAIL. THE UPPER TROUGH IS FORECAST TO SHIFT SLOWLY E 
AND WEAKEN SLIGHTLY DURING THE NEXT 24 HOURS...WITH ASSOCIATED 
WEATHER ALSO SHIFTING EASTWARD TOWARDS 120W.

A STRONG AND POWERFUL DEEP LAYERED CYCLONE IS MOVING SLOWLY NE 
ACROSS THE NE CENTRAL PACIFIC THIS MORNING...LOCATED WELL NW OF 
THE HAWAIIAN ISLANDS. THE LOW WILL SHIFT NE OVER THE NEXT FEW 
DAYS WITH AN ASSOCIATED COLD FRONT STALLING JUST NW OF THE 
DISCUSSION AREA BY 48 HOURS. SEVERAL PULSES OF STRONG AND LARGE 
NW SWELL WILL MOVE THROUGH THE AREA DURING THE NEXT SEVERAL DAYS 
AND EVENTUALLY PRODUCE LARGE AND DANGEROUS SURF ALONG THE 
PACIFIC COASTS FROM CALIFORNIA TO CHILE. THE FIRST PULSE OF 
SWELL HAS ENTERED THE AREA WATERS IN THE PAST 24 HOURS AND WAS 
MOVING SOUTHEASTWARD ACROSS 100W EARLY THIS MORNING...WITH SEAS 
8 TO 12 FT GENERALLY WEST OF A LINE FROM 30N117W TO 15N115W TO 
07N120W TO 00N128W. A NEW PULSE OF NW SWELL WAS JUST ENTERING NW 
PORTIONS THIS MORNING AND BUILDING SEAS TO NEAR 12 FT ACROSS THE 
FAR NW CORNER OF THE AREA. A THIRD AND LARGER PULSE OF NW SWELL 
WILL ARRIVE INTO NW PORTIONS BY 48 HOURS AND BUILD SEAS 10 TO 15 
FT AND HIGHER BY THURSDAY AFTERNOON. 

NE SWELL GENERATED FROM GAP WINDS...IN TEHUANTEPEC AND TO A 
LESSER EXTENT IN PAPAGAYO...WILL PREVAIL E OF 110W DURING THE 
NEXT FEW DAYS AND MIX DOWNSTREAM WITH THE PREVAILING NW SWELL. 

GAP WINDS...                                                    
GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE 
IN THE GULF OF MEXICO AND LOWER PRESSURE ASSOCIATED WITH THE 
MONSOON TROUGH NEAR PANAMA CONTINUES TO PRODUCE DIURNAL PULSES 
OF NE WINDS TO 25 KT ACROSS PAPAGAYO AND DOWNWIND TO 88W-89W. 
HIGH PRESSURE BUILDING IN THE WAKE OF A COLD FRONT MOVING ACROSS 
THE GULF OF MEXICO LATER TODAY WILL STRENGTHEN WINDS IN GULF OF 
PAPAGAYO OVERNIGHT TONIGHT WED MORNING...AND EVENTUALLY PRODUCE 
NORTHERLY FLOW ACROSS THE GULF OF PANAMA TO 25 KT BY THU 
MORNING. 

$$
STRIPLING