000
AXPZ20 KNHC 081531
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC WED JUL 8 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC. 

...TROPICAL WAVES...                                    

A TROPICAL WAVE ALONG 111W BETWEEN 07N-14N IS MOVING W AT 15-20 
KT. IT IS ENHANCING CONVECTION ALONG THE ITCZ AXIS S OF THE WAVE 
BETWEEN 106W-116W.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

MONSOON TROUGH FROM 08N81W TO 07N87W TO 08N99W TO 07N106W. ITCZ 
EXTENDS FROM 07N106W TO 05N121W TO 07N131W. SCATTERED MODERATE 
CONVECTION WITHIN 75 NM S OF MONSOON TROUGH BETWEEN 92W AND 99W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM S OF 
AXIS BETWEEN 105W AND 116W.

...DISCUSSION...

THE COMBINATION OF TROPICAL DEPRESSION 4-E MOVING AWAY FROM THE 
AREA AND A WEAK TROUGH EXTENDING FROM A LOW N OF THE AREA NEAR 
34N129W TO 28N135W HAS WEAKENED THE SURFACE RIDGE OVER NORTHERN 
WATERS AND CAUSED THE PRESSURE GRADIENT ACROSS THE REGION N OF 
THE CONVERGENCE ZONE TO RELAX SIGNIFICANTLY. AS A RESULT GENTLE 
TO MODERATE TRADE WINDS PREVAIL OVER MOST OF THE AREA N OF 10N 
AND W OF 110W.

A BROAD UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 24N121W. A TUTT 
EXTENDS FROM 31N92W IN THE GULF OF MEXICO ACROSS SOUTHERN MEXICO 
TO 9N97W. WATER VAPOR IMAGERY SHOWS STRONG NORTHERNLY FLOW ALOFT 
BETWEEN 99W-105W. AN UPPER LEVEL TROUGH IS MOVING W IN THE DEEP 
TROPICS BETWEEN 129W-132W SOUTH OF 16N.

A LARGE AREA OF LONG PERIOD SW SWELL SWEEPING NORTHWARD FROM THE 
SOUTHERN HEMISPHERE W OF THE GALAPAGOS ISLANDS WILL CONTINUE TO 
PROPAGATE NORTH-NORTHEAST...COVERING SOUTHERN WATERS S OF 08N 
BETWEEN 100W-125W THROUGH LATE TONIGHT..THEN GRADUALLY SUBSIDE 
THU AND FRI.

LOOKING AHEAD...GFS AND ECMWF MODELS AGREE AND SHOW A TROPICAL 
LOW DEVELOPING SOUTH OF MEXICO THIS WEEKEND AS A TROPICAL WAVE 
MOVES IN PHASE WITH PRE-EXISTING CYCLONIC CIRCULATION ASSOCIATED 
WITH AN AREA OF LOW PRESSURE EMBEDDED WITHIN THE MONSOON TROUGH. 
CYCLONIC VORTICITY GENERATED BY GAP WINDS FROM PAPAGAYO AND 
TEHUANTEPEC MAY PLAY A SIGNIFICANT ROLE IN SPINNING UP THE LOW.
 
GAP WINDS...

THE PRESSURE GRADIENT NEAR THE GULF OF TEHUANTEPEC IS EXPECTED 
TO TIGHTEN THU MORNING AS AN APPROACHING TROPICAL WAVE CURRENTLY 
IN THE WESTERN CARIBBEAN NEAR 83W PASSES S OF THE AREA. EXPECT 
NORTHERLY WINDS OF 20-25 KNOTS N OF 15N THU...DIMINISHING 
BRIEFLY IN THE EVENING...THEN PICKING UP AGAIN EARLY FRIDAY 
MORNING. EXPECT MAX SEAS TO 8-9 FT ON FRIDAY.

STRONG CARIBBEAN TRADE WINDS CONTINUE TO SPILL ACROSS SOUTHERN 
CENTRAL AMERICA THROUGH THE GULF OF PAPAGAYO INTO THE EASTERN 
PACIFIC. FRESH E-NE WINDS WILL PULSE IN A DIURNAL CYCLE THE NEXT 
2 DAYS WITH HIGHEST WINDS AROUND 25 KT EXPECTED DURING LATE 
NIGHT AND EARLY MORNING HOURS. MAX SEAS WILL BE AROUND 8 FT 
BETWEEN 87W-93W DOWNSTREAM FROM THE AREA OF MAX WINDS EARLY FRI.

THE PRESSURE GRADIENT WILL INCREASE IN THE FAR NORTHERN GULF OF 
CALIFORNIA LATE TONIGHT AND EARLY THU...THEN AGAIN THU NIGHT AND 
FRI MORNING AS A THERMAL TROUGH FROM SOUTHERN CALIFORNIA TO 
NORTHERN BAJA CALIFORNIA DEEPENS. WIND SPEEDS MAY BRIEFLY REACH 
20-25 KT...BUT SEAS WILL BE WELL BELOW 8 FT WITH MAX SEAS 
EXPECTED AROUND 4-5 FT THU MORNING...AND AGAIN FRI MORNING.

$$
MUNDELL