000
AXPZ20 KNHC 310335
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JAN 31 2013

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

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

THE MONSOON TROUGH IS ALONG 03N78W TO 08N84W TO 05N92W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N92W TO 
07N117W TO 04N140W. SCATTERED MODERATE CONVECTION IS WITHIN 150 
NM N OF THE ITCZ BETWEEN 111W AND 117W AND ALSO WITHIN 180 NM N 
OF THE ITCZ BETWEEN 118W AND 126W.

...DISCUSSION...

NEARLY STATIONARY STRONG 1035 MB HIGH PRES IS CENTERED N OF THE 
AREA NEAR 39N133W WITH AN ASSOCIATED RIDGE EXTENDING OVER THE 
FORECAST WATERS FROM THE HIGH THROUGH 32N130W TO NEAR 16N110W. 
THE PRES GRADIENT SW OF THE RIDGE AND LOWER PRES IN THE VICINITY 
OF THE ITCZ IS MAINTAINING FRESH TO STRONG TRADES OVER MUCH OF 
THE W CENTRAL PORTION OF THE FORECAST AREA FROM 07N TO 17N W OF 
120W...AND FROM 09N TO 16N BETWEEN 113W AND 120W. AN AREA OF 
8-13 FT SEAS SURROUNDS THESE WINDS...WITH THE MAXIMUM SEAS 
OCCURRING COINCIDENT WITH THE STRONGEST WINDS. THE HIGH PRES AND 
ATTENDANT RIDGE IS FORECAST TO WEAKEN DURING THE NEXT 24-48 
HOURS WHILE SHIFTING SLIGHTLY TO THE NE. AS A RESULT THE AREAL 
COVERAGE OF THE TRADE WINDS WILL DECREASE SIGNIFICANTLY...WITH 
WINDS EVEN DIMINISHING TO 20 KT OR LESS BY FRI EVENING.

THE PRES GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER WESTERN 
MEXICO IS RESULTING IN FRESH TO STRONG WINDS IN THE GULF OF 
CALIFORNIA S OF 30N. SEAS OF 8-9 FT ARE SPILLING OUT OF THE 
MOUTH OF THE GULF TO 17N BETWEEN 105W AND 110W. HIGH PRES WILL 
CONTINUE TO BUILD ACROSS THE U.S. GREAT BASIN REGION TONIGHT 
WITH BROAD TROUGHING INCREASING OVER MEXICO...MAINTAINING THESE 
MARINE CONDITIONS OVERNIGHT. THE HIGH WILL THEN WEAKEN THU 
RELAXING THE PRES GRADIENT WITH WINDS DIMINISHING TO 20 KT OR 
LESS BY EARLY FRI MORNING.

GAP WINDS...
GULF OF TEHUANTEPEC...A STRONG COLD FRONT CURRENTLY EXTENDING 
FROM THE FLORIDA BIG BEND SW TO MEXICO NEAR 18N95W WILL RAPIDLY 
SHIFT EASTWARD ACROSS THE REMAINDER OF THE GULF OF MEXICO... 
PUSHING E OF THE BAY OF CAMPECHE LATE TONIGHT. A DENSER AIR MASS 
BEHIND THIS FRONT WILL FUNNEL THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC. WINDS WILL RAPIDLY RAMP UP TO GALE FORCE BY 
06 UTC TONIGHT...AND TO STRONG GALE FORCE BY 12-18 UTC THU. 
STRONG HIGH PRES BUILDING BEHIND THE FRONT OVER EASTERN MEXICO 
AND THE WESTERN GULF OF MEXICO WILL HELP TO MAINTAIN THESE 
CONDITIONS THROUGH EARLY FRI EVENING. ALL THE GLOBAL MODELS AND 
THE NAM REGIONAL MODEL CONTINUE TO CAP WINDS IN THE 30-45 KT 
RANGE...HOWEVER IT IS STILL MARGINALLY POSSIBLE THAT MINIMAL 
STORM FORCE WINDS MAY BRIEFLY OCCUR (925 MB WINDS AND 30M 
GUIDANCE WINDS ARE UP TO 50-60 KT). THIS WILL NEED TO BE 
MONITORED IN CASE THE WARNING NEEDS TO BE UPGRADED PRIOR TO 
THESE CONDITIONS. ALL OF THE MODEL GUIDANCE IS IN AGREEMENT WITH 
RESPECT TO THE TIMING OF THE PEAK WINDS (BETWEEN 1200-1800 UTC 
THU). RESULTANT SEAS WILL BUILD TO UP TO 18 FT DURING THE PEAK 
WINDS.

GULF OF PAPAGAYO...FRESH TO STRONG WINDS WILL DEVELOP IN THIS 
AREA LATER TONIGHT. THE STRONGEST WINDS WILL OCCUR DURING THE 
LATE NIGHT AND EARLY MORNING HOURS WITH THE ADDED COMPONENT OF 
NOCTURNAL DRAINAGE FLOW...AND WEAKER WINDS WILL BE PRESENT 
DURING THE AFTERNOON AND EARLY EVENING HOURS. WINDS WILL 
INCREASE FURTHER UP TO 30 KT WHILE FRESH TO STRONG WINDS COVER A 
LARGER AREA BY EARLY FRI MORNING ALLOWING FOR SEAS TO BUILD TO 
10 FT JUST DOWNWIND OF THE GULF.

GULF OF PANAMA...FRESH TO STRONG WINDS WILL SPREAD ACROSS THE 
ISTHMUS OF PANAMA FROM THE SW CARIBBEAN SEA TO THE GULF OF 
PANAMA BY LATE THU NIGHT THROUGH FRI. SEAS WILL BUILD TO UP TO 
8-9 FT DOWNWIND OF THE GULF DURING THAT SAME TIME FRAME.

$$
LEWITSKY