000
AXPZ20 KNHC 150918
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC THU JAN 15 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...NORTHERLY FLOW BETWEEN A 
FRONTAL BOUNDARY STALLED ALONG 94W OVER THE SW GULF OF MEXICO 
AND RIDGING ALONG THE NE MEXICAN COAST IS FUNNELING THROUGH THE 
ISTHMUS OF TEHUANTEPEC. GALE FORCE WINDS ARE EXPECTED TO 
DIMINISH AROUND SUNRISE TODAY AS WINDS IN THE SW GULF 
TEMPORARILY SLACKEN AHEAD OF A NEW SURGE OF NORTHERLY FLOW THAT 
IS EXPECTED TO MOVE INTO THE GULF OF TEHUANTEPEC AROUND SUNSET 
TODAY. WINDS TO MINIMAL GALE FORCE ARE THEN EXPECTED TO 
CONTINUE IN THE GULF OF TEHUANTEPEC THROUGH THE END OF THE 
FORECAST PERIOD ON SAT MORNING...WITH THE AREA OF GALE FORCE 
WINDS EXPECTED TO BE LARGER DURING THE PERIOD OF MAXIMUM 
DRAINAGE FLOW OFF THE MOUNTAINS IN THE EARLY MORNINGS AND 
SMALLER DURING THE DIURNAL MINIMUM OF DRAINAGE FLOW IN THE LATE 
AFTERNOON. SEAS IN THE 9-13 FT RANGE ARE EXPECTED IN THE GULF OF 
TEHUANTEPEC THROUGH SAT MORNING.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N77W TO 06N79W TO 
08N84W TO 07N90W. THE ITCZ AXIS WAS ANALYZED FROM 07N90W TO 
07N108W...THEN CONTINUES FROM 08N112W TO 07N140W. TROUGH FROM 
14N109W TO 07N111W...SCATTERED MODERATE CONVECTION WAS WITHIN 
150 NM E OF THE TROUGH FROM 09N TO 14N. 

...DISCUSSION...                                                 

THE SUBTROPICAL RIDGE EXTENDS FROM 1026 MB HIGH PRESSURE NEAR 
34N124W THROUGH 29N128W TO 16N105W. A DISSIPATING STATIONARY 
FRONT LIES JUST W OF THE RIDGE FROM 32N132W 24N134W. A WESTERN 
SPOKE OF THE SUBTROPICAL RIDGE IS EXPECTED TO EXPAND LATER TODAY 
ACROSS NW WATERS. TO THE S...A SERIES OF SURFACE TROUGHS LIE N 
OF THE ITCZ ALONG 134W...122W AND 110W. THESE TROUGHS ARE ALL 
ASSOCIATED WITH MID-LEVEL ENERGY FOUND WITHIN A BROAD TROUGH 
CENTERED ALONG 125W. THIS TROUGH IS EXPECTED TO CUT OFF A DEEP 
LAYER LOW OVER THE NEXT 24 HOURS. AN ASSOCIATED SURFACE LOW IS 
FORECAST TO DEVELOP NEAR 15N120W BY FRI MORNING AND MOVE NW 
THROUGH THE END OF THE FORECAST PERIOD SAT MORNING. THE PRES 
GRADIENT BETWEEN THE LOW AND THE EXPANDING SUBTROPICAL RIDGE 
SHOULD BE STRONG ENOUGH TO SUPPORT A FRESH TO STRONG 
BREEZE...POSSIBLY INCREASING TO NEAR GALE FORCE. THIS LOW WILL 
BE A FOCUS FOR DEEP CONVECTION. 

GAP WINDS...                                               
    
GULF OF PAPAGAYO...TRADE WINDS IN THE SW CARIBBEAN CONTINUE TO  
FUNNEL THROUGH NORTHERN COSTA RICA INTO THE GULF OF PAPAGAYO. 
FRESH TO STRONG E-NE WINDS IN PLACE THIS MORNING ARE ALSO 
EXPECTED FRI MORNING AND SAT MORNING DURING THE PERIOD OF 
MAXIMUM NOCTURNAL DRAINAGE FLOW. WINDS AND SEAS WILL BRIEFLY 
DIMINISH DURING THE AFTERNOON HOURS.
 
GULF OF CALIFORNIA...A SLOW MOVING POSITIVELY TILTED UPPER 
TROUGH WILL MOVE EASTWARD THROUGH THE SOUTHWESTERN UNITED STATES 
OVER THE NEXT FEW DAYS. AT THE SURFACE...THE PRESSURE GRADIENT 
WILL BUILD BETWEEN LEE SIDE TROUGHING ALONG THE W SLOPES OF THE 
SIERRA MADRE OCCIDENTAL AND INCREASED RIDGING OVER THE GREAT 
BASIN IN THE WAKE OF THE UPPER TROUGH. THE NORTHERN GULF OF 
CALIFORNIA HAS A FRESH N-NW BREEZE IN PLACE THIS MORNING AND MAY 
SEE AN OCCASIONAL STRONG BREEZE N OF 28N DURING THE NEXT DAY OR 
SO.

$$
SCHAUER