000
AXPZ20 KNHC 171450
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE JUL 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...SPECIAL FEATURES... 
TROPICAL STORM FABIO AT 22.3N 120.5W AT 1500 UTC MOVING N AT 10 
KT WITH MAXIMUM WINDS 40 KT GUSTS TO 50 KT. SCATTERED MODERATE 
CONVECTION LIES WITHIN 90 NM NE SEMICIRCLE OF FABIO. FABIO IS 
BEING STEERED NORTHWARD ON THE LEADING EDGE OF A DEEP LAYERED 
TROUGH OVER N MEXICO AND CALIFORNIA. THIS TROPICAL STORM IS 
FORECAST TO WEAKEN TO A TROPICAL DEPRESSION BY EARLY WED MORNING 
AS IT ENCOUNTERS COOLER WATERS...A DRIER AIR MASS AND INCREASING 
VERTICAL SHEAR. SEE THE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADER MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH AXIS FROM 08N77W TO 10N90W TO 11N104W TO 07N115W 
TO 08N120W. ITCZ AXIS FROM 08N120W TO 09N126W TO 05N140W. 
SCATTERED MODERATE ISOLATED STRONG S OF AXIS TO 03N E OF 86W... 
AND FROM 04N TO 11N BETWEEN 90W AND 120W. 

...DISCUSSION...
THE 1036 MB SUBTROPICAL HIGH RESIDES WELL NW OF THE FORECAST 
AREA NEAR 43N151W. A RIDGE EXTENDS SOUTHEASTWARD FROM THE HIGH 
CENTER TO 24N132W. DEEP LAYER TROUGHING IS OVER CALIFORNIA AND N 
MEXICO. THE SURFACE PRESSURE GRADIENT TIGHTENS UP OVER THE NW 
CORNER OF FORECAST AREA. WINDS ARE 20 KT OR LESS OVER THE 
FORECAST AREA...WITH THE EXCEPTION OF FABIO AND A SMALL AREA OF 
20 KT WINDS N OF 28N W OF 135W THAT WILL DIMINISH LATER TODAY.  
N SWELL CONTINUES TO MOVE INTO WATERS N OF 28N TODAY WHERE IT IS 
ENCOUNTERING THE SE SWELL GENERATED BY FABIO. 

A BROAD ANTICYCLONE ALOFT SPANS MUCH OF THE REGION FROM 05N TO 
20N BETWEEN 90W AND 120W. THE DIFFLUENCE ALOFT ON THE SOUTHERN 
EDGE OF THE ANTICYCLONE IS ENHANCING CONVECTION ALONG THE 
MONSOON TROUGH BY PROVIDING VERTICAL LIFT TO THE LOW LEVEL 
MOISTURE POOLED ALONG THE TROUGH. THE ANTICYCLONE WILL SHRINK ON 
ITS EASTERN EDGE WED INTO EARLY THU AS AN INVERTED UPPER TROUGH 
CURRENTLY E OF 90W PLOWS WESTWARD. WHILE THE MONSOON TROUGH IS 
EXPECTED TO REMAIN ACTIVE...THERE IS NO SIGNIFICANT MID TO LOW 
LEVEL FEATURE EXPECTED TO SPIN UP ALONG IT OVER THE NEXT FEW 
DAYS.

GAP WINDS..FRESH TO OCCASIONALLY STRONG WINDS IN THE GULF OF 
PAPAGAYO WILL PULSE OVER THE NEXT FEW DAYS. THE STRONGEST WINDS 
WILL COME IN THE EARLY MORNING HOURS WHEN DRAINAGE FLOW OFF THE 
LAND IS AT A MAXIMUM.  

$$
FORMOSA