000
AXPZ20 KNHC 172219
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN FEB 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...SPECIAL FEATURE...
STRONG NORTH TO NORTHEAST WINDS ACROSS THE SOUTHERN GULF OF 
MEXICO AND WESTERN CARIBBEAN PERSIST THIS AFTERNOON BEHIND A 
STRONG COLD FRONT. STORM FORCE WINDS THROUGH THE GULF OF 
TEHUANTEPEC HAVE DIMINISHED BELOW STORM FORCE THIS AFTERNOON... 
AND ARE ESTIMATED TO BLOWING 30 TO 40 KT THROUGH AND DOWNSTREAM 
OF TEHUANTEPEC THIS AFTERNOON...TO NEAR 98W. THIS "NORTERO" 
ACROSS CENTRAL AMERICA IS ALSO DRIVING WINDS TO NEAR 30 KT 
THROUGH AND DOWNSTREAM OF THE GULF OF PAPAGAYO...WERE A 1200 UTC 
WINDSAT PASS SHOWED 25-30 KT NE WINDS THIS MORNING...AND 20-25 
KT WINDS THROUGH THE GULF OF FONSECA...AND DOWNSTREAM TO 90W. 
GLOBAL MODELS GUIDANCE IS IN GENERAL AGREEMENT THAT THIS STRONG 
COLD NORTHERLY FLOW WILL INDUCE GALES TONIGHT THROUGH THE GULF 
OF PAPAGAYO AND DOWNSTREAM TO TO NEAR 90W...AND UNUSUAL EVENT. 
THESE GALES ARE LIKELY TO LAST UNTIL THE MORNING HOURS...BEFORE 
ABATING BELOW GALE FORCE BY MID MORNING. GALES THROUGH THE GULF 
OF TEHUANTEPEC WILL DIMINISH TONIGHT TO MINIMAL GALES...AND 
ABATE BELOW GALE FORCE AROUND SUNRISE. A VERY LARGE AREA OF 
CONFUSED AND HIGH SEAS WILL BE GENERATED BY THIS BROAD SCALE 
REGIONAL EVENT...WITH SEAS 8 TO 12 FT IN A MIX OF N AND NE 
SWELL...FROM 04N TO 14N E OF 108W...WHICH WILL IMPACT THE N AND 
NE COAST LINES OF THE GALAPAGOS ISLANDS DURING THE DAY MONDAY.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
ITCZ FROM 05N106W TO 08N187W TO 04N140W. SCATTERED TO LOCALLY 
NUMEROUS MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM N OF 
ITCZ W OF 131W.

...DISCUSSION...
A COMPLEX SERIES OF UPPER LEVEL TROUGHS AND SHORTWAVES ACROSS 
THE CENTRAL AND NE PACIFIC THE PAST FEW DAYS HAS MERGED INTO A 
LONGWAVE TROUGH EXTENDING FROM THE NW U.S. SOUTHWESTWARD ACROSS 
THE NW CORNER OF THE DISCUSSION AREA TO AND ELONGATED WEAKENING 
VORTEX IN THE BASE OF THIS TROUGH JUST OFF THE N COAST OF THE 
BIG ISLAND OF HAWAII. BROAD SCALE RIDGING PREVAILS ACROSS MOST 
OF THE REMAINDER OF THE DISCUSSION AREA SOUTHEAST OF THIS 
FEATURE...EXCEPT FOR AN EQUATORIAL UPPER TROUGH FROM 13N118W TO 
02N11W. A BROAD ZONE OF WEST TO SOUTHWEST FLOW OVER THE RIDGE 
EXTENDS FROM S OF THE HAWAIIAN ISLANDS INTO BAJA CALIFORNIA AND 
N MEXICO...WITH JET CORE OF 75-110 KT CURRENTLY ENTERING FAR 
BAJA CALIFORNIA NORTE...EXTREME NW MEXICO AND INTO THE DESERT SW 
OF THE U.S. 

AT THE SURFACE...THE E PACIFIC HIGH PRES RIDGE HAS REORGANIZED 
OVER THE E CENTRAL PACIFIC WELL N OF THE HAWAIIANS ISLANDS 
EXTENDING SE TO NEAR 23N116W. THE PRESSURE GRADIENT BETWEEN THE 
RIDGE AND THE ITCZ IS MAINTAINING FRESH TO STRONG NE TRADEWINDS 
ACROSS SW PORTIONS OF THE AREA...WITH ASSOCIATED LOW LEVEL 
CONVERGENCE INDUCING AN AREA OF MODERATE TO STRONG CONVECTION 
DESCRIBED ABOVE. DIFFLUENT UPPER LEVEL FLOW ACROSS THIS AREA 
AIDING IN THE DEEP CONVECTION HAS CREATED A LARGER SEAM IN THE 
UPPER FLOW...INDUCING STRONG UPPER DIVERGENCE ACROSS THIS AREA.

ELSEWHERE...PULSES OF NWLY SWELL CONTINUE TO PROPAGATE INTO THE 
REGIONAL WATERS...AND WILL MAINTAIN SEAS 8 FT AND HIGHER ACROSS 
THE THIRD OF THE AREA THROUGH TUE.

$$
STRIPLING