000
AXPZ20 KNHC 072148
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC WED JAN 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC. 

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...PERSISTENT STRONG HIGH 
PRESSURE EXTENDING SOUTHWARD FROM THE CENTRAL U.S. ALONG THE 
MEXICO COASTAL PLAINS TO SOUTH CENTRAL MEXICO CONTINUES TO  
MAINTAIN A TIGHT PRESSURE GRADIENT INTO THE GULF OF TEHUANTEPEC. 
THIS IS SUPPORTING STRONG GALE FORCE WINDS FLUCTUATING 40 TO 45 
KT THROUGH THE GULF OF TEHUANTEPEC...WITH GALE FORCE WINDS 
EXTENDING DOWNWIND SOME 220-240 NM. ANOTHER AREA OF VERY STRONG 
HIGH PRESSURE PRODUCING THE VERY COLD TEMPERATURES ACROSS MOST 
OF THE E AND CENTRAL U.S. WILL REINFORCE THE PRESSURE GRADIENT 
ACROSS E AND SE MEXICO TO MAINTAIN THIS STRONG GALE EVENT 
THROUGH FRI MORNING...WITH WINDS EXPECTED TO FLUCTUATE AT AND 
JUST BELOW MINIMAL GALE FORCE THROUGH THE UPCOMING WEEKEND. NE 
TO E SWELL ASSOCIATED WITH THIS EVENT COMBINED WITH A GALE WIND 
EVENT OVER THE GULF OF PAPAGAYO IS PRODUCING A VERY LARGE AREA 
OF SEAS 8 FT OR GREATER THAT EXTENDS SW TO BEYOND 110W. BY THU 
EVENING...SEAS 8 FT OR GREATER WILL COVER MUCH OF THE AREA S OF 
14N BETWEEN 92W AND 125W.

GULF OF PAPAGAYO GALE WARNING...THIS SAME STRONG PRESSURE 
GRADIENT IS COMBINING WITH STRONG TRADEWINDS ACROSS THE CENTRAL 
AND SW CARIBBEAN TO SUPPORT AN UNUSUALLY STRONG GAP WIND EVENT 
ACROSS THE GULF OF PAPAGAYO...WITH WINDS 30-35 KT EXTENDING SW 
AND DOWNWIND TO 92W. WINDS ARE EXPECTED TO DIMINISH TO 25-30 KT 
DURING THE AFTERNOON...AND THEN PULSE AGAIN TO GALE FORCE 
TONIGHT THROUGH THE EARLY MORNING HOURS THU. WINDS WILL DIMINISH 
AND REMAIN 25-30 KT THU AFTERNOON THROUGH FRI AFTERNOON AS HIGH 
PRESSURE N OF THE AREA WEAKENS MODESTLY. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
             
THE MONSOON TROUGH EXTENDS FROM THE COAST OF COLOMBIA NEAR 
05N77W TO 03N81W TO 05N87W...THEN TRANSITIONS TO ITCZ... 
CONTINUING ON TO 06N120W TO 08N130W TO 07N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 05N TO 08N 
BETWEEN 107W AND 114W. SCATTERED MODERATE CONVECTION IS WITHIN 
12O NM N OF ITCZ BETWEEN 120W AND 123W.
 
...DISCUSSION...                                                 

HIGH PRESSURE OVER THE WESTERN U.S. EXTENDS A RIDGE SW OVER NE 
WATERS TO NEAR 20N130W. A COLD FRONT IS OVER THE NW PART OF THE 
FORECAST AREA AND EXTENDS FROM 30N134W TO 21N140W. THE PRESSURE 
GRADIENT BETWEEN THESE FEATURES IS SUPPORTING SOUTHERLY WINDS OF 
20-30 KT AHEAD OF THE FRONT...PARTICULARLY N OF 26N AND WITHIN 
180 NM E OF FRONT. ALSO...THE PRESSURE GRADIENT BETWEEN THE 
RIDGE AND LOWER PRESSURE ALONG THE ITCZ IS MAINTAINING A LARGE 
AREA OF FRESH TO LOCALLY STRONG WINDS N OF THE ITCZ W OF 110W. 
TRADE WIND CONVERGENCE IS PRODUCING MODERATE TO ISOLATED STRONG 
CONVECTION AS MENTIONED ABOVE. THE COLD FRONT WILL SHIFT 
EASTWARD AND GRADUALLY WEAKEN THROUGH FRI...WITH WINDS GRADUALLY 
DIMINISHING...BECOMING 20 KT OR LESS ON THU. ASSOCIATED NW 
SWELLS WILL PROPAGATE E-SE WITH SEAS PEAKING NEAR 14 FT BY THIS 
EVENING. 

FRESH TO LOCALLY STRONG N WINDS ARE FUNNELING INTO THE GULF OF 
PANAMA FROM THE CARIBBEAN. WINDS WILL PULSE TO 25 KT DURING LATE 
NIGHT AND EARLY MORNING HOURS TONIGHT AND THU NIGHT AND DIMINISH 
TO 20 KT OR LESS DURING THE AFTERNOON AND EARLY EVENING HOURS. 

$$ 
GR