000
AXPZ20 KNHC 201532
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JAN 20 2012

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...

THE MONSOON TROUGH IS ALONG 03N77W TO 07N86W TO 04N90W. THE 
INTERTROPICAL CONVERGENCE ZONE EXTENDS FROM 04N90W TO 06N115W TO 
04N140W. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 180 
NM N OF ITCZ BETWEEN 115W AND 135W.

...DISCUSSION...

MARINE WEATHER ACROSS OUR AREA OF RESPONSIBILITY IS RELATIVELY 
QUIET THIS MORNING.  A MODERATELY STRONG SURFACE HIGH OF 1024 MB 
IS CENTERED NEAR 28N127W.  THE PRESSURE GRADIENT BETWEEN THIS 
HIGH AND LOW PRESSURE OVER THE SW UNITED STATES AND NW MEXICO IS 
PRODUCING FRESH NW WINDS JUST WEST OF NORTHERN BAJA CALIFORNIA.  
ADDITIONALLY THE PRESSURE GRADIENT BETWEEN THE HIGH AND LOW 
PRESSURE ASSOCIATED WITH THE ITCZ IS CAUSING FRESH NE TRADEWINDS 
BETWEEN 05N AND 17N W OF 120W. BOTH THE NW WINDS OFF OF BAJA 
CALIFORNIA AND THE NE TRADEWINDS WILL CHANGE LITTLE DURING THE 
NEXT TWO DAYS.

A VIGOROUS UPPER LEVEL TROUGH ALONG 30N120W TO 18N127W IS 
CONTRIBUTING TOWARD NUMEROUS AMOUNTS OF MID TO HIGH LEVEL 
CLOUDINESS BEING ADVECTED FROM THE ITCZ TOWARD WESTERN MEXICO.  
THE UPPER TROUGH ALSO HAS A COMPONENT REACHING THE LOWER LEVELS 
OF THE ATMOSPHERE AS A SURFACE TROUGH EXTENDS FROM 20N126W TO 
17N127W.  THIS FEATURE WAS WELL-DEPICTED FROM THE 0612Z ASCAT 
SCATTEROMETER SURFACE WIND MEASUREMENTS.  WHILE THE SURFACE 
TROUGH HAS BEEN ASSOCIATED WITH NUMEROUS LIGHTNING STRIKES 
EMBEDDED WITHIN FAIRLY LOW-TOPPED CONVECTION...NO OUT OF SEASON 
TROPICAL CYCLONE DEVELOPMENT IS EXPECTED DUE TO STRONG WIND 
SHEAR AND LACK OF CONVECTIVE INSTABILITY.

NW SWELL WITH SIGNIFICANT WAVE HEIGHTS OF 12 FEET WITH A PERIOD 
AROUND 15 S SHOULD BEGIN IMPACTING THE NW CORNER OF OUR AREA OF 
RESPONSIBILITY STARTING SAT MORNING.  THESE WILL PEAK NEAR 14 
FEET IN THE VICINITY OF 30N125W SUN MORNING BEFORE SLOWLY 
DIMINISHING BELOW 12 FEET BY MON NIGHT.

NO GALE FORCE WIND EVENTS APPEAR TO BE LIKELY FOR THE NEXT WEEK 
IN OUR AREA OF RESPONSIBILITY.

...GAP WINDS...

GULF OF PAPAGAYO...FRESH TO STRONG WINDS OVER THE SW CARIBBEAN 
CONTINUE TO FUNNEL THROUGH THE GAPS IN THE TOPOGRAPHY OF 
NICARAGUA AND COSTA RICA ACROSS THE GULF OF PAPAGAYO. THESE NE 
TO E WINDS ARE FORECAST TO PERSIST THROUGH AT LEAST SAT NIGHT 
AND WEAKEN SUN MORNING. THE STRONGEST WINDS WILL OCCUR DURING 
THE LATE NIGHT AND EARLY MORNING HOURS WITH THE ADDED COMPONENT 
OF NOCTURNALLY DRIVEN KATABATIC WINDS.

GULF OF PANAMA...FRESH WINDS FROM THE SW CARIBBEAN ARE ALSO 
FUNNELING ACROSS THE ISTHMUS OF PANAMA DOWNWIND ACROSS THE GULF 
OF PANAMA. THESE WINDS WILL DIMINISH TO LESS THAN 20 KT BY SAT 
EVENING AS WINDS IN THE SW CARIBBEAN BEGIN TO DIMINISH.

GULF OF TEHUANTEPEC...THE EARLIER GAP WIND EVENT IN THIS AREA 
HAS ENDED.  THE NEXT ONSET IS LIKELY TO BEGIN MON NIGHT...BUT 
DOES NOT AT THIS POINT APPEAR TO BE OF GALE FORCE INTENSITY.

$$
LANDSEA