000
AXPZ20 KNHC 301546
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED JAN 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N84W TO 05N93W. ITCZ CONTINUES 
FROM 05N93W TO 07N115W TO 05N130W TO 05N140W. NO SIGNIFICANT 
CONVECTION IS NOTED.

...DISCUSSION...

STRONG HIGH PRESSURE 1038 MB IS CENTERED N OF THE AREA NEAR 
39N133W WITH ASSOCIATED RIDGE EXTENDING OVER THE FORECAST WATERS 
TO NEAR 15N105W. THE PRESSURE GRADIENT BETWEEN THE AREA OF HIGH 
PRESSURE AND LOWER PRESSURE IN THE VICINITY OF THE ITCZ IS 
MAINTAINING STRONG TRADES OVER MUCH OF THE FORECAST AREA N OF 
05N AND W OF 115W. SCATTEROMETER DATA PROVIDED OBSERVATIONS OF 
THESE WIND SPEEDS. THE HIGH PRES IS FORECAST TO REMAIN NEARLY 
STATIONARY OVER THE NEXT 24 HOURS WHILE WEAKENING. AS A 
RESULT...THE AREAL COVERAGE OF THE STRONG TRADE WINDS WILL 
DECREASE. 

THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURES OVER 
WESTERN MEXICO IS RESULTING IN FRESH TO STRONG WINDS IN THE 
SOUTHERN HALF OF THE GULF OF CALIFORNIA AND ALSO DOWNSTREAM OF 
THIS GULF TO AROUND 18N AND E OF 109W WHERE WINDS INCREASE TO 3O 
KT. A COUPLE OF SHIP OBSERVATIONS ALONG WITH SCATTEROMETER DATA 
CONFIRMED THE PRESENCE OF THESE STRONG WINDS. HIGH PRESSURE WILL 
BUILD ACROSS THE GREAT BASIN REGION TODAY WITH BROAD TROUGHING 
INCREASING OVER MEXICO. THIS WILL EXPAND THE STRONG WINDS ALONG 
MUCH OF THE GULF OF CALIFORNIA. THE AREA OF HIGH PRESSURE WILL 
THEN WEAKEN THURSDAY AND RELAX THE PRESSURE GRADIENT TO BRING 
WINDS BELOW 20 KT BY FRI MORNING. 

GAP WINDS...
GULF OF TEHUANTEPEC...A STRONG COLD FRONT...CURRENTLY EXTENDING 
FROM SE LOUISIANA TO NEAR TAMPICO MEXICO...WILL RAPIDLY SHIFT 
ACROSS THE GULF OF MEXICO...REACHING THE BAY OF CAMPECHE THIS 
EVENING. 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 THU...AND STRONG GALE 
FORCE BY 12 UTC THU. STRONG HIGH PRES BUILDING BEHIND THE FRONT 
IN THE GULF OF MEXICO WILL HELP TO MAINTAIN THESE CONDITIONS 
THROUGH FRI MORNING. ALL THE GLOBAL MODELS AND THE NAM REGIONAL 
MODEL SUGGEST WINDS IN THE 30-45 KT RANGE. HOWEVER...IT IS NOT 
OUT OF THE QUESTION THE POSSIBILITY OF MINIMAL STORM FORCE WINDS 
(925 MB WINDS AND 30M GUIDANCE WINDS ARE UP TO 50-55 KT) WHICH 
WILL NEED TO BE MONITORED IN CASE THE WARNING NEEDS TO BE 
UPGRADED PRIOR TO THE EVENT. ALL MODELS ARE IN AGREEMENT SHOWING 
THIS EVENT PEAKING BETWEEN 1200-1800 UTC THU. EXPECT BUILDING 
SEAS UP TO 16 FT WITH THESE GALE TO NEAR STORM FORCE WINDS. 

GULF OF PAPAGAYO...EXPECT INCREASING WINDS ACROSS THIS AREA BY 
EARLY THU MORNING WITH THE STRONGEST WINDS OF 20-30 KT OVER A 
BROAD AREA ROUGHLY FROM 08N TO 11N E OF 91W BY FRI MORNING. 
THESE STRONG WINDS WILL RAISE SEAS TO AROUND 10 FT. AS USUAL...  
THE STRONGEST WINDS WILL OCCUR DURING THE LATE NIGHT AND EARLY 
MORNING HOURS WITH THE ADDED COMPONENT OF NOCTURNAL DRAINAGE 
FLOW...AND WEAKER WINDS DURING THE AFTERNOON AND EARLY EVENING 
HOURS.

GULF OF PANAMA...FRESH TO STRONG WINDS WILL SPREAD ACROSS THE 
ISTHMUS OF PANAMA TO THE GULF OF PANAMA BY THU EVENING FROM THE 
SW CARIBBEAN SEA...BUILDING SEAS TO UP TO 9 FT DOWNWIND OF THE 
GULF BY FRI.

$$
GR