000
AXPZ20 KNHC 120909
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC MON JAN 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0730 UTC. 

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...THE PRESSURE GRADIENT REMAINS 
STRONG BETWEEN RIDGING EXTENDING FROM NE MEXICO TOWARD THE 
ISTHMUS OF TEHUANTEPEC AND TROUGHING TO THE S ALONG THE ITCZ. 
THIS RIDGE IS FORECAST TO PERSIST ALONG THE NORTHEASTERN MEXICAN 
COASTAL PLAIN AND WILL BE REINFORCED BY STRONGER HIGH PRES 
EXTENDING S ACROSS THE CENTRAL PLAINS OF THE UNITED STATES BY 
TONIGHT. WINDS TO MINIMAL GALE FORCE ARE ONGOING IN THE GULF OF 
TEHUANTEPEC...BUT ARE EXPECTED TO DIP BELOW GALE FORCE THIS 
AFTERNOON AND RETURN AGAIN DURING THE PERIOD OF MAXIMUM DRAINAGE 
FLOW OFF THE MOUNTAINS OVERNIGHT TONIGHT. THE PATTERN SHOULD 
REPEAT ITSELF AGAIN TUE/WED...WITH WINDS WEAKEST IN THE 
AFTERNOON AND EARLY EVENING AND REACHING MINIMAL GALE FORCE IN 
THE LATE NIGHT AND EARLY MORNING HOURS. SEAS ARE EXPECTED TO 
REACH AROUND 12 FEET DURING THE MORNINGS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N78W TO 05.5N80W TO 
09N85W TO 07N90W. THE ITCZ AXIS WAS ANALYZED FROM 07N90W TO 
06N98W TO 10N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 360 
NM N OF THE AXIS BETWEEN 117W AND 130W AND WITHIN 150 NM S OF 
THE AXIS BETWEEN 123W AND 133W. 
  
...DISCUSSION...                                                 

ENERGY ON THE W SIDE OF A BROAD UPPER TROUGH CENTERED LONG 135W 
IS REFLECTING A SURFACE TROUGH FROM 16N136W TO 09N139W. RECENT 
LIGHTNING DATA SHOWS ACTIVE THUNDERSTORMS IN THE AREA ON THE N 
EDGE OF THE TROUGH FROM 15N TO 22N BETWEEN 130W AND 139W. 
PRECIPITABLE WATER IMAGERY SHOWS MOISTURE IS POOLED AHEAD OF 
THIS TROUGH AND UNDER AN AREA OF UPPER LEVEL SPEED DIVERGENCE. 
CONVECTION IS EXPECTED TO ACCOMPANY THE TROUGH THROUGH THE END 
OF THE FORECAST PERIOD ON WED MORNING. ANOTHER BATCH OF 
SHORTWAVE ENERGY LIES ON THE E SIDE OF THE TROUGH AND IS 
ENHANCING THE TROUGHING ALONG THE MONSOON TROUGH AT THE SURFACE. 
THE ASCAT-A PASS FROM 0600 UTC SHOWS FRESH TO STRONG E WINDS N 
OF THE ITCZ BETWEEN 120W AND 125W IN ADDITION TO E-SE WINDS 
FOUND E OF THE AFOREMENTIONED SURFACE TROUGH. THE STRONGEST 
WINDS AND CONVECTION SHOULD FOCUS NEAR THE SURFACE TROUGH OVER 
THE NEXT DAY OR TWO AS IT SLOWLY MOVES E OF 130W. 

A COLD FRONT IS EXPECTED TO INCH INTO NW WATERS TUE NIGHT AND 
WEAKEN AS IT MOVES TO NEAR 30N135W TO 26N140W BY WED MORNING. 
WINDS ARE EXPECTED TO BE A FRESH S BREEZE JUST AHEAD OF THE 
FRONT...WITH SEAS BUILDING TO 12 FT IN NW SWELL IN THE FAR NW 
WATERS BY WED MORNING. 

GAP WINDS...                                                   
GULF OF PAPAGAYO...E-NE WINDS ARE NEAR GALE FORCE THIS MORNING 
IN THE GULF OF PAPAGAYO. ONCE THE DRAINAGE FLOW FROM THE 
MOUNTAINS DIMINISHES AFTER SUNRISE...WINDS ARE EXPECTED TO 
DIMINISH TO 20 KT OR LESS. WINDS WILL CONTINUE TO PULSE LIKE 
THIS THROUGH THE FORECAST PERIOD...BUT RIDGING N OF THE AREA 
WILL BEGIN TO WEAKEN TODAY...KEEPING THE GAP WINDS HERE TO A 
FRESH TO STRONG BREEZE TUE MORNING AND WED MORNING. 

 
$$
SCHAUER