000
AXPZ20 KNHC 152204
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI FEB 15 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS IS NO DISCERNIBLE ON THE 1800 UTC MAP. 
THE ITCZ EXTENDS FROM A 1010 MB LOW PRES 09N98W TO 06N108W TO 
08N118W TO 04N140W. NO SIGNIFICANT CONVECTION.

...DISCUSSION...
THE HIGH PRES RIDGE ACROSS THE NE PACIFIC CONTINUES TO WEAKEN 
THIS AFTERNOON...CENTERED ON A 1033 MB HIGH NEAR 36N138W AND 
EXTENDING A RIDGE AXIS SE THROUGH 30N130W TO 25N114W. THE 
PRESSURE GRADIENT BETWEEN THIS RIDGE AND THE ITCZ CONTINUES TO 
SUPPORT A BROAD AREA OF 20-25 KT TRADE WINDS N OF THE ITCZ FROM 
04N TO 20N W OF 132W AND FROM 07N TO 14N BETWEEN 122W AND 
132W...WHERE SEAS ARE RUNNING 8 TO 12 FT IN MIXED NE AND NW 
SWELL. THE HIGH WILL WEAKEN FURTHER AS IT SHIFTS SOUTHWESTWARD  
EVENTUALLY MERGING WITH HIGH PRESSURE BEHIND A COLD FRONT 
FORECAST TO MOVE N OF AREA OVERNIGHT TONIGHT. THIS WILL WEAKEN 
THE RIDGING OVER THE FORECAST WATERS AND CAUSE TRADES TO 
GRADUALLY SHIFT WESTWARD AND DIMINISH TO A FRESH TO STRONG NE 
BREEZE THROUGH SUN MORNING. 

A WEAKENING UPPER TROUGH REMAINS NEARLY STATIONARY OVER THE NW 
CORNER OF FORECAST AREA...WHILE A BROAD AND ENERGETIC UPPER 
TROUGH SHIFTING E OF THE HAWAIIAN ISLANDS APPROACHES SW PORTIONS 
OF THE AREA. UPPER RIDGING S OF 22N AND W OF 125W DOMINATES SE 
PORTIONS. A BROAD 80-110 KT UPPER JET IS ON THE E SIDE OF THE 
TROUGHS AND RIDES OVER THE RIDGE FROM 15N130W THROUGH 27N113W 
THEN EAST-SOUTHEASTWARD ACROSS THE N HALF OF MEXICO. THESE 
STRONG WINDS ARE TRANSPORTING ABUNDANT MID TO UPPER LEVEL 
MOISTURE FROM THE ITCZ NEAR 130W ACROSS BAJA CALIFORNIA 
PENINSULA AND N MEXICO AND ARE BEGINNING TO REACH THE FAR WRN 
GULF OF MEXICO.  

GAP WINDS...
GULF OF CALIFORNIA...THE STRONG PRESSURE GRADIENT BETWEEN THE NE 
PACIFIC RIDGE AND TROUGHING OVER NORTHERN MAINLAND MEXICO IS 
RESULTING IN FRESH TO STRONG N-NW WINDS ACROSS THE NORTH AND 
CENTRAL PORTIONS OF THE GULF. THE PRES GRADIENT IS FORECAST TO 
REMAIN STRONG EVEN AS THE SUBTROPICAL RIDGE WEAKENS. A FRESH TO 
STRONG BREEZE IS FORECAST TO CONTINUE UNTIL LATE SAT MORNING 
WITH WINDS OF 20 KT OR LESS SAT EVENING. 

GULF OF TEHUANTEPEC...ATTENTION REMAINS FOCUSED ON THE NEXT GULF 
OF TEHUANTEPEC STRONG GAP WIND EVENT...FORECAST TO BE THE SECOND 
STORM FORCE WIND EVENT THIS YEAR. A REINFORCING COLD FRONT WILL 
QUICKLY MOVE ACROSS THE GULF OF MEXICO OVERNIGHT TONIGHT 
FOLLOWED BY STRONG NLY WINDS. THESE WINDS WILL FUNNEL THROUGH 
THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC...AND WILL QUICKLY 
INCREASE TO GALE FORCE BY SAT AFTERNOON THEN TO STORM FORCE BY 
SAT EVENING. THIS EVENT IS EXPECTED TO PERSIST THROUGH SUN 
MORNING. A GALE WARNING IS IN EFFECT BEGINNING AT 16/1800 UTC 
FOLLOWED BY STORM WARNING AT 17/0000 UTC. WAVEWATCH MODEL 
GUIDANCE SUGGESTS THAT SEAS WILL BUILD TO 15-24 FT IN 
ASSOCIATION WITH THESE STRONG WINDS LATE SAT NIGHT THROUGH EARLY 
SUN.

GULF OF PAPAGAYO...STRENGTHENING HIGH PRESSURE OVER THE GULF OF 
MEXICO AND NW CARIBBEAN WILL INCREASE THE PRESSURE GRADIENT 
BETWEEN THIS RIDGING AND LOWER PRESSURE TO THE SW ALONG THE ITCZ 
TO YIELD FRESH TO STRONG NE WINDS IN THE GULF OF PAPAGAYO SAT 
NIGHT THROUGH EARLY SUN...INCREASING TO 25-30 KT BY SUNRISE 
SUN.  

$$
STRIPLING