000
AXPZ20 KNHC 232145
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU AUG 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2045 UTC.

...TROPICAL WAVE...

THE TROPICAL WAVE PREVIOUSLY LOCATED OVER CENTRAL MEXICO WITH 
AXIS ALONG 99W IS NO LONGER DISCERNIBLE ON THE 1800 UTC SURFACE 
MAP OR SATELLITE IMAGERY.  

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

MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 12N102W TO 10N115W TO 
12N135W THEN ITCZ AXIS CONTINUES TO 1010 MB LOW PRES NEAR 
11N139W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
FROM 06N TO 11N BETWEEN 80W AND 90W...FROM 08N TO 13N BETWEEN 
90W AND 98W AND FROM 12N TO 17N BETWEEN 101W AND 106W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF TROUGH AXIS 
FROM 110W TO 118W.

...DISCUSSION...

A BROAD ANTICYCLONE ALOFT OVER CENTRAL BAJA CALIFORNIA NEAR 
27N113.5W EXTENDS A RIDGE WWD ACROSS THE N WATERS TO NEAR 135W 
WITH ANOTHER RIDGE TO THE E AND SE OVER NORTH-CENTRAL MEXICO.  
WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE AND 
IMPLIED DRY AIR MASS WITHIN THE RIDGE. BROADLY DIFFLUENT 25 TO 
30 KT E-NE FLOW S OF THE ANTICYCLONE LIES OVER THE SURFACE LOW 
PRES SYSTEM NEAR 20N110W. 

A 1010 MB SURFACE LOW PRES SYSTEM LIES NEAR 20N110W WHILE THE 
REMNANTS OF HECTOR ARE STILL SEEN ON SATELLITE IMAGERY NEAR 
19N115W. IN BETWEEN THESE LOWS...A NARROW LINE OF SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED. THE 1732 UTC  
ASCAT PASS DEPICTED A CLOSED CIRCULATION AROUND THE LOW CENTER 
NEAR 20N110W...WITH WINDS REMAINING AT 10 TO 15 KT. THIS LOW IS 
FORECAST TO GRADUALLY OPEN UP INTO A TROUGH OVER THE NEXT 36-48 
HOURS AS THE SHEAR ALOFT TAKES ITS TOLL ON THE SYSTEM. 

HIGH PRESSURE 1030 MB IS CENTERED NEAR 45N140W WITH WEAK RIDGE 
EXTENDING SE TO NEAR 24N118W. TRADEWINDS ACROSS THE AREA ARE 
GENERALLY IN THE 10 TO 15 KT RANGE...WITH A FRESH BREEZE FOUND 
ON THE N SIDE OF 1010 MB LOW PRES NEAR 11N139W WHERE THE 
PRESSURE GRADIENT IS TIGHTEST. SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS ARE NEAR THE LOW CENTER. THIS LOW IS FORECAST TO 
OPEN UP INTO A TROUGH AS IT SHIFTS W OF THE FORECAST AREA LATE 
TODAY. 

AN AREA OF DISTURBED WEATHER HAS FORMED A FEW HUNDRED MILES 
SOUTH-SOUTHWEST OF THE COAST OF GUATEMALA.  SOME SLOW DEVELOPMENT
OF THIS SYSTEM IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT 
MOVES GENERALLY WESTWARD AT 10 TO 15 MPH.  THIS SYSTEM HAS A LOW 
CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

CROSS-EQUATORIAL SE TO S SWELL WITH COMBINED SEAS TO 8 FT WILL 
PREVAIL OVER THE FORECAST AREA GENERALLY S OF 04N W OF 125W 
THROUGH FRI. A SECOND AREA OF 8 FT SEAS WILL MOVE INTO THE AREA 
S OF 03N BETWEEN 92W AND 120W SAT. 

$$
GR