000
AXPZ20 KNHC 040923
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC SAT JUL 04 2015

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. 
 
...SPECIAL FEATURES... 

LOW LATITUDE LOW PRESSURE IS CENTERED NEAR 06N122W. THE LOW 
FORMED ALONG A WELL DEFINED TROPICAL WAVE IN A LARGE AREA OF 
CONVECTION GENERATED BY A KELVIN WAVE. CONVECTION CURRENTLY 
ASSOCIATED TO THE LOW IS FOUND WITHIN 300 NM NW QUADRANT. 
NORTHEASTERLY SHEAR CONTINUES TO AFFECT THE SYSTEM BUT 
CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR TROPICAL 
CYCLONE DEVELOPMENT OVER THE NEXT FEW DAYS AS THE LOW MOVES W-
NW. 

...TROPICAL WAVES...                                     
TROPICAL WAVE AXIS NEAR 100W N OF 10N. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WAS NOTED WITHIN 90 NM OF THE WAVE 
FROM 10N TO 14N.

TROPICAL WAVE AXIS NEAR 112W FROM 08N TO 14N. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED NEAR THE WAVE FROM 07N TO 
10N BETWEEN 110W AND 115W. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM 09N83W TO 07N92W TO 08N97W. 
THERE IS NO ITCZ. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WAS NOTED WITHIN 120 NM OF THE MONSOON TROUGH BETWEEN 90W AND 
97W.

...DISCUSSION... 

HIGH PRESSURE OF 1017 MB CENTERED NEAR 27N129W EXTENDS A RIDGE 
SE TO NEAR 18.5N110W. A 1008 MB LOW CENTERED NEAR 13N138W IS 
SLOWLY DRIFTING NW. THE PRESSURE GRADIENT BETWEEN THE AREA OF 
HIGH PRESSURE AND THE LOW IS PRODUCING FRESH WINDS N OF THE LOW. 
THE FRESH WINDS ARE HELPING FOR SEAS TO 8 FT FROM 14N TO 17N W 
OF 132W. THE LOW WILL MOVE W OF THE AREA LATE SUNDAY NIGHT. 
CONVECTION ASSOCIATED TO THE LOW HAS DECREASED AND CONDITIONS 
ARE BECOMING LESS FAVORABLE FOR TROPICAL CYCLOGENESIS. THE 
PRESSURE GRADIENT BETWEEN THE RIDGE OF HIGH PRESSURE AND LOW 
PRESSURE CENTERED OVER SOUTHERN CALIFORNIA HAS WEAKENED. AS A 
RESULT...THE STRONG WINDS OFF THE COAST OF BAJA CALIFORNIA NORTE 
HAVE DIMINISHED TO 20 KT OR LESS. 

A KELVIN WAVE MOVING THROUGH THE AREA CONTINUES TO HELP FOR 
ENHANCED LOW LEVEL CONVERGENCE AND ACTIVE WEATHER FROM 05N TO 
11N BETWEEN 97W AND 120W. THE ACTIVE CONVECTION ASSOCIATED WITH 
THE KELVIN WAVE HELPED FOR THE GENERATION OF BOTH LOW PRESSURE 
SYSTEMS DESCRIBED ABOVE. THE CONTINUED CONVECTION HAS ALSO 
HELPED TO GENERATE AN UNSTABLE BACKGROUND ENVIRONMENT WHICH HAS 
LED TO A BREAKDOWN OF THE ITCZ. 

THE CARIBBEAN JET EXTENDING INTO THE FAR EASTERN NORTH PACIFIC 
CONTINUES TO PRODUCE PULSING OF STRONG GAP WIND FLOW OVER THE 
GULF OF PAPAGAYO. THE MAIN PULSES ARE OCCURRING OVERNIGHT...WITH 
A PLUME OF SHORTER PERIOD SWELL TO 8 FT PROPAGATING AS FAR WEST 
AS 92W DOWNSTREAM DURING THE DAY. FRESH GAP WINDS WILL CONTINUE 
THROUGH THE GULF OF PANAMA OVER THE NEXT 24 TO 48 HOURS. 

$$
AL