000
AXPZ20 KNHC 200920
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JUL 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO 09N85W TO A 1008 
MB LOW PRES NEAR 07N99W TO 14N111W TO A 1010 MB LOW PRES NEAR 
08N126W TO 06N128W THEN ITCZ TO BEYOND 07N140W. SCATTERED 
MODERATE TO STRONG FROM 05N TO THE COAST OF PANAMA E OF 83W. 
SCATTERED MODERATE ISOLATED STRONG FROM 06N TO 09N BETWEEN 98W 
AND 102W. SCATTERED MODERATE WITHIN 90 NM N OF AXIS BETWEEN 118W 
AND 121W.

...DISCUSSION...
A 1034 MB SUBTROPICAL HIGH CENTERED WELL NW OF THE FORECAST AREA 
NEAR 41N160W WITH RIDGE EXTENDING SE TO NEAR 20N113W. THE 
PRESSURE GRADIENT BETWEEN THIS FEATURE AND LOW PRESSURE EMBEDDED 
IN THE MONSOON TROUGH NEAR 08N126W IS MAINTAINING FRESH 20 KT 
WINDS FROM 10N TO 14N BETWEEN 125W AND 138W. THIS AREA OF TRADES 
WILL SHIFT WESTWARD OVER THE NEXT 48 HOURS WITH THE MOVEMENT OF 
THE LOW PRESSURE CENTER. A SECOND LOW PRESSURE CENTER EMBEDDED 
IN THE MONSOON TROUGH NEAR 07N99W IS THE RESULT OF A TROPICAL 
WAVE. TROPICAL CYCLONE FORMATION IS NOT EXPECTED IN ASSOCIATION 
WITH EITHER OF THESE LOWS DURING THE NEXT 48 HOURS. BEYOND 48 
HOURS...GLOBAL MODELS CONTINUE TO INDICATE A LOW PRESSURE CENTER 
FORMING WITHIN THE MONSOON TROUGH. THIS LOW PRESSURE AREA WILL 
ALSO BE THE RESULT OF A TROPICAL WAVE...CURRENTLY OVER THE 
EASTERN CARIBBEAN...INTERACTING WITH THE TOPOGRAPHY OF CENTRAL 
AMERICA AND THE MONSOON TROUGH. THE GFS CONTINUES TO BE THE MOST 
AGGRESSIVE IN DEVELOPING THIS LOW. 

CROSS EQUATORIAL LONG PERIOD SW SWELLS OF 18-20 SECONDS WILL 
SPREAD ACROSS THE FORECAST AREA AND WILL IMPACT THE COAST OF 
MEXICO...CENTRAL AMERICA AND BAJA CALIFORNIA LATE THIS WEEK 
THROUGH THE WEEKEND. THE POTENTIAL EXISTS FOR LARGE BREAKING 
WAVES AND DANGEROUS RIP CURRENTS ALONG THE COAST THROUGH THE 
WEEKEND AS THE SWELL TRAIN SLOWLY SUBSIDES. 

GAP WINDS OF 20 KT...WITH PULSES TO 25 KT ARE EXPECTED TO 
CONTINUE OVER THE GULF OF PAPAGAYO AS FRESH TO STRONG TRADE WIND 
FLOW IN THE SW CARIBBEAN FUNNELS THROUGH THE GAP. THE WINDS WILL 
BE GREATEST DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH 
THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. FRESH TO STRONG 
GAP WINDS WILL ALSO START THROUGH THE GULF OF TEHUANTEPEC TODAY 
AND CONTINUE THROUGH THE NEXT 48 HOURS. 

$$
AL