000
AXPZ20 KNHC 131542
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC MON APR 13 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...              

PRIMARY ITCZ FROM 05N90W TO 03N95W 04N114W TO 06N122W TO 
07N140W. SECONDARY ITCZ FROM 03.4S87W TO 01S94W TO 3.4S102W TO 
04S107W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM ITCZ TO 
09N BETWEEN 133W AND 137W. SCATTERED TO NUMEROUS STRONG WITHIN 
30 NM EITHER SIDE OF LINE FROM 08N82W TO 05N85W...WITHIN 30 NM 
EITHER SIDE OF LINE FROM 06N85W TO 04N87W TO 04N91W...AND FROM 
02S TO 03S BETWEEN 87W AND 89W. SCATTERED MODERATE ISOLATED 
STRONG FROM 02S TO 04S BETWEEN 90W AND 97W...AND FROM 06N TO 10N 
FROM 138W WESTWARD.

A SURFACE TROUGH IS ALONG 06N77W 05N78W. CONVECTIVE 
PRECIPITATION...NUMEROUS STRONG FROM 04N TO 07N E OF 78W.

...DISCUSSION... 

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS MOVING THROUGH THE 
NORTHERN PART OF THE FORECAST AREA...PASSING THROUGH 32N134W TO 
30N135W. A SEPARATE MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS 
FROM A 29N133W CYCLONIC CIRCULATION CENTER BEYOND 23N140W. 
COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR 
IMAGERY FROM 22N110W 22N134W 20N135W 20N140W NORTHWARD. MIDDLE 
LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE AREA THAT IS 
FROM 20N NORTHWARD FROM 100W WESTWARD. 
 
A SURFACE RIDGE PASSES THROUGH 32N127W TO 21N116W AND TO 
17N106W. A SURFACE TROUGH IS ALONG 132W/133W FROM 25N NORTHWARD.

THE SUBTROPICAL RIDGE HAS BEEN WEAKENED ACROSS N WATERS...BUT IT 
SHOULD STRENGTHEN GRADUALLY THROUGH THE END OF THE FORECAST 
PERIOD ON TUESDAY EVENING. HIGH PRESSURE...THAT MOVES INTO THE 
AREA BEHIND A COLD FRONT...IS EXPECTED TO PUSH INTO THE WESTERN 
U.S.A. ON MONDAY NIGHT. TRADE WINDS SHOULD PICK UP TO A FRESH 
BREEZE IN THE WESTERN WATERS ON TUESDAY. THE WIND SPEEDS ARE 
EXPECTED TO REACH ADVISORY CRITERIA IN A BELT FROM 22N TO 24N 
BETWEEN 129W AND 137W INTO TUESDAY AFTERNOON AND TUESDAY 
EVENING. NORTHERLY WINDS ALONG THE CALIFORNIA COAST ALSO WILL 
INCREASE AS THE PRESSURE GRADIENT BUILDS BETWEEN THE FRONT THAT 
IS IN THE INTERIOR WESTERN U.S.A. AND THE COMPARATIVELY HIGHER 
PRESSURES THAT ARE MORE TO THE NORTHWEST.

A SHARP UPPER LEVEL TROUGH PASSES THROUGH NICARAGUA AND 
NORTHWESTERN COSTA RICA...BEYOND A MIDDLE LEVEL TO UPPER LEVEL 
CYCLONIC CIRCULATION CENTER THAT IS NEAR GALAPAGOS ISLANDS.  AN 
UPPER LEVEL RIDGE IS IN COLOMBIA...AND IT IS ENCROACHING UPON 
THE AREA OF THIS RARE CROSS-EQUATORIAL TUTT. THE SCATTERED TO 
NUMEROUS STRONG CONVECTIVE PRECIPITATION THAT IS FROM 03N TO 08N 
BETWEEN 82W AND 92W IS RELATED TO THE TROUGH...JUST TO THE EAST 
OF THE ITCZ.

$$
MT