000
AXPZ20 KNHC 172145
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JAN 17 2012

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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM 06N77W TO 04N93W. THE ITCZ 
AXIS EXTENDS FROM 04N93W TO 06.5N115W TO BEYOND 05N140W. 
SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 150 NM S OF AXIS 
BETWEEN 80W AND 85W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 150 NM N OF AXIS BETWEEN 110W AND 
120W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 150 NM N OF AXIS BETWEEN 128W AND 132W.

...DISCUSSION...

HIGH PRES 1031 MB IS CENTERED N OF THE AREA NEAR 33N127W WITH 
RIDGE EXTENDING SE TO NEAR 17N106W. THE PRESSURE GRADIENT 
BETWEEN THIS FEATURE AND LOWER PRESSURE IN THE VICINITY OF THE 
ITCZ IS MAINTAINING FRESH TRADEWINDS FROM 7N TO 20N W OF 120W 
AND FROM 07N TO 14N BETWEEN 110W AND 120W. THIS AREA OF 
EXTENSIVE FRESH TRADEWINDS IS HELPING TO ABSORB MORE ENERGY FROM 
THE SEA SURFACE. IN TURN THE CONVERGENCE OF THIS MORE ENERGETIC 
AIR INTO THE ITCZ IS ENHANCING CONVECTION AS MENTIONED ABOVE. 
THE AREA OF HIGH PRESSURE WILL CONTINUE TO SHIFT SOUTHWARD AND 
CLOSER TO THE FORECAST AREA. THIS WILL MAINTAIN THE LARGE 
COVERAGE OF FRESH TO STRONG TRADEWINDS THROUGH AT LEAST THU 
AFTERNOON. ADDITIONALLY...THE PROXIMITY OF THE AREA OF HIGH 
PRESSURE AND A TROUGH OF LOW PRESSURE OVER MEXICO WILL TIGHTEN 
THE PRESSURE GRADIENT OVER THE GULF OF CALIFORNIA AND OFF THE 
COAST OF CABO CORRIENTES MEXICO. THIS TIGHTENED PRESSURE 
GRADIENT WILL PRODUCE FRESH NW TO N WINDS OVER THE GULF OF 
CALIFORNIA AND S TO NEAR 18N OFF THE COAST OF MEXICO STARTING 
TONIGHT.

...GAP WINDS...
GULF OF TEHUANTEPEC...WITH WINDS VEERING OVER THE GULF OF 
MEXICO...WINDS FUNNELING THROUGH THE CHIVELA PASS INTO THE GULF 
OF TEHUANTEPEC HAVE DIMINISHED. CURRENTLY FRESH WINDS TO 20 KT 
PREVAIL OVER THE GULF OF TEHUANTEPEC. NOCTURNAL DRAINAGE FLOW 
DURING THE OVERNIGHT HOURS WILL YIELDS NLY WINDS 20-25 KT LATE 
TONIGHT THROUGH WED MORNING. HIGH PRES BEHIND A WEAK COLD FRONT 
EXPECTED ACROSS THE NE GULF WED IS EXPECTED TO INCREASE THE 
GRADIENT WIND FLOW THROUGH THE GULF OF TEHUANTEPEC TO NEAR 30 KT 
BY WED EVENING. 

GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE N 
OF THE CARIBBEAN AND LOWER PRESSURE OVER SOUTH AMERICA IS 
PRODUCING FRESH TO STRONG TRADEWINDS OVER THE FAR WESTERN 
CARIBBEAN. THESE WINDS ARE FUNNELING THROUGH GAPS IN THE THE 
TOPOGRAPHY OF NICARAGUA AND COSTA RICA INTO THE GULF OF 
PAPAGAYO. THIS WILL CONTINUE THROUGH AT LEAST WED EVENING WITH 
WINDS PEAKING DURING THE EARLY MORNING HOURS WITH THE ADDED 
COMPONENT OF NOCTURNALLY DRIVEN KATABATIC WINDS. MEANWHILE THE 
WINDS OVER THE SW CARIBBEAN ARE ALSO FUNNELING INTO THE GULF OF 
PANAMA PRODUCING FRESH NLY WINDS. THESE WINDS OVER THE GULF OF 
PANAMA ARE ALSO EXPECTED TO CONTINUE THROUGH THE NEXT 48 HOURS.

$$
AL