000
AXPZ20 KNHC 102154
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN FEB 10 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 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
ITCZ AXIS FROM 01N80W TO 04N95W THEN MONSOON TROUGH TO 1010 MB 
LOW PRES AT 03N106W THEN TO 08N118W TO 07N121W WHERE IT TURN 
INTO ITCZ AGAIN TO 06N127W TO 04N140W.  ISOLATED MODERATE 
CONVECTION WITHIN 120 NM N OF AXIS E OF 97W.

...DISCUSSION...
PREVIOUSLY FLATTENED-CREST RIDGE NOW ABLE TO BUILD N AS LONGWAVE 
TROUGH PULLS EASTWARD.  MODEL GUIDANCE INDICATES RIDGE IS STRONG 
ENOUGH TO WARD OFF APPROACHING DEEP LAYER CYCLONE DEVELOPING 
FROM VIGOROUS SHORT WAVE JUST W OF BASIN.  CYCLONE PLUNGES S 
ROUNDING BASE OF UPSTREAM LONGWAVE UPPER LEVEL TROUGH AND 
APPROACHES NW CORNER WITH ATTENDANT SURFACE LOW PRES AND COLD 
FRONT.  IF GUIDANCE SOLUTIONS ARE CORRECT...COLD FRONT SHOULD 
STALL JUST W OF 140W WITH ASSOCIATED GALE FORCE WINDS JUST W OF 
E PAC BASIN.  GFS AND CANADIAN SOLUTIONS THE MOST AGGRESSIVE 
WHILE UKMET AND ECMWF LESS SO...BUT INCH COLD FRONT CLOSER TO 
140W.  EITHER WAY WIND AND SEAS CONDITIONS LIKELY TO DETERIORATE 
BY END OF PERIOD IN WESTERN FRINGES OF BASIN.  LOW PRES CENTER 
LIKELY TO TIGHTEN GRADIENT ENOUGH TO INCREASE TRADES AND SEAS W 
OF 120W.

SECOND DEEP LAYER CYCLONE SUPPORTS WEAK LOW PRES CENTER 1010 MB 
AT 03N106W ALONG ITCZ...BUT SURROUNDING AIR MASS REMAINS VERY 
DRY WITH ONLY ISOLATED MODERATE CONVECTION NOTED E OF 97W.  MID 
TO UPPER LEVEL ANTICYCLONE OVER PANAMA SUPPLIES MINOR AMOUNT OF 
TROPICAL MOISTURE TO PROMPT CONVECTION. 

...ELSEWHERE AT THE LOWER LEVELS...
HIGH PRES CENTER 1033 MB N OF BASIN MOVE FURTHER NE ALLOWED  
TRADES TO DIMINISH TO A MODERATE BREEZE W OF 120W.  SWELLS FROM 
PREVIOUS GALE EVENT N OF AREA REMAIN 10-13 FT N OF 20N AND 8-10 
FT S OF 20N W OF 114W.  TRADES EXPECTED TO INCREASE TO A STRONG 
BREEZE AGAIN...OR EVEN NEAR GALE FORCE...AS PRES GRADIENT WITH 
APPROACHING LOW PRES CENTER W OF BASIN INCREASE.  LONG NE FETCH 
MAY BUILD SEAS HIGHER THAN THE 11-13 FT NWW3 INDICATES.

GAP WINDS...
STRONG E WINDS OVER SW CARIBBEAN SUPPORT FRESH TO STRONG BREEZE 
ACROSS NICARAGUA INTO GULF OF PAPAGAYO.  STRONGER WINDS PULSE 
DURING OVERNIGHT AND EARLY MORNING HOURS WHEN DRAINAGE IS 
STRONG...THEN DIMINISH DURING LATE MORNING INTO EARLY EVENING. 
SEAS BRIEFLY BUILD AS MUCH AS 8 FT DURING STRONGER WINDS. 

LOOKING WELL AHEAD...E PAC SURFACE RIDGE MOVING INLAND 
CALIFORNIA TIGHTENS PRES GRADIENT WITH STATIONARY SURFACE TROUGH 
ALONG CENTRAL MEXICO AND PROMPT STRONG NW WINDS ALONG GULF OF 
CALIFORNIA WITH TRAPPED SEA HEIGHTS REACHING 8 FT BY LATE WED.

$$
WALLY BARNES