000
AXPZ20 KNHC 241527
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC FRI APR 24 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. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

ITCZ AXIS EXTENDS FROM 06N96W TO 06N112W TO 07N119W THROUGH LOW 
PRES 1010 MB NEAR 07N121W TO 04N125W TO 04N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 75 NM OF LOW.

...DISCUSSION... 

A RIDGE-TROUGH-RIDGE UPPER LEVEL PATTERN CONTINUES ACROSS THE 
AREA THIS MORNING...AND PERSISTS DUE TO THE LARGE DOWNSTREAM 
BLOCKING RIDGE ACROSS THE GULF OF MEXICO AND FAR E PACIFIC E OF 
105W. A MIDDLE TO UPPER LAYER TROUGH DOMINATES MOST OF THE AREA 
N OF 10N AND W OF 105W...AND EXTENDS N ACROSS THE NE PACIFIC AND 
WESTERN U.S. NUMEROUS SHORT WAVE CAN BE SEEN IN WATER VAPOR 
IMAGERY MOVING THROUGH THIS MEAN CIRCULATION...AND ARE GRADUALLY 
ERODING THE WESTERN PERIPHERY OF THE BLOCKING RIDGE. A 70-90 KT 
UPPER JET IS MOVING THROUGH THE BASE OF THE TROUGH ALONG 14-16N 
AND ACCELERATES TO 85-100 PLUS KT AS SW WINDS LIFT OUT OF THE 
TROUGH AND OVER THE GULF OF MEXICO RIDGE. ABUNDANT MIDDLE TO 
UPPER LEVEL MOISTURE EMBEDDED IN THIS FLOW IS STREAMING N-NE 
AHEAD OF TROUGH ACROSS WESTERN MEXICO...TEXAS AND THE GULF COAST 
STATES.

A 1029 MB HIGH IS CENTERED NEAR 34N143W AND ANCHORS A BROAD 
RIDGE ACROSS THE NORTH AND WESTERN WATERS...EXTENDING FROM THE 
HIGH TO NEAR 16N108W. OVERNIGHT SCATTEROMETER DATA SHOWED AN 
AREA OF FRESH TO STRONG TRADE WINDS IN A TRIANGULAR AREA ROUGHLY 
DEFINED FROM 23N140W TO 20N132W TO 10N124W TO 04N140W WHERE NE 
TO E WINDS WERE 20-25 KT AND SEAS RUNNING 9 TO 12 FT. THE HIGH 
WILL SHIFT SLOWLY SE AND WEAKEN SLIGHTLY OVER THE WEEKEND WHICH 
WILL GRADUALLY REDUCE THE AREA OF STRONG TRADES TO BETWEEN 10N 
AND 16N AND W OF 124W BY SUN.

STRONG NWLY WINDS ACROSS THE CALIFORNIA COASTAL WATERS ARE 
GENERATING NORTHERLY SWELL THAT IS MOVING S AND ACROSS NE 
PORTIONS OF THE AREA...WITH SEAS PRESENTLY 8 TO 11 FT NW OF A 
LINE FROM 30N117W TO 26N117W TO 20N124W TO 23N140W. THIS SWELL 
WILL GRADUALLY FADE THROUGH SAT BEFORE A NEW PULSE OF NORTHERLY 
SWELL INVADES THESE NE WATERS SAT NIGHT THROUGH SUN AND BUILDS 
SEAS 8 TO 10 FT N OF 25N.

MODEL GUIDANCE INDICATES W TO SW WINDS 20-25 KT ACROSS THE 
EXTREME NORTHERN GULF OF CALIFORNIA THIS MORNING OCCURRING E OF 
A SURFACE TROUGH EXTENDING FROM SOUTHERN CALIFORNIA INTO THE N 
HALF OF THE GULF. THIS TROUGH IS EXPECTED TO LINGER IN THIS 
GENERAL VICINITY OVER THE WEEKEND...BUT THE PRESSURE GRADIENT ON 
THE EAST SIDE WILL WEAKEN...WITH WINDS EXPECTED TO REMAIN AROUND 
15-20 KT. 

SOUTHEAST OF THE SURFACE RIDGE...LIGHT TO MODERATE VARIABLE 
WINDS PREVAIL ACROSS THE EASTERN WATERS. WEAK SOUTHWESTERLY 
WINDS WERE OBSERVED BY OVERNIGHT SCATTEROMETER PASSES E OF 
96W...AND SUGGEST THAT THE EASTERN PACIFIC MONSOONAL CIRCULATION 
IS GRADUALLY EVOLVING. A WEAK EASTERLY WAVE HAS EMERGED OFF OF 
COLOMBIA AND SOUTH AMERICA AND IS MOVING WESTWARD ACROSS THE FAR 
EASTERN PACIFIC...AND HAS HELPED TO TRIGGER SEVERAL CLUSTERS OF 
DEEP CONVECTION DESCRIBED ABOVE E OF 98W. THIS ACTIVE WEATHER IS 
EXPECTED TO SHIFT WESTWARD DURING THE NEXT 24 HOURS.
  
$$ 
STRIPLING