000
AXPZ20 KNHC 150333
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT SEP 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM KRISTY CENTERED NEAR 21.2N 113.8W AT 0300 UTC 
MOVING NW AT 8 KT. MAXIMUM SUSTAINED WINDS 40 KT WITH GUSTS TO 
50 KT AND MINIMUM PRESSURE OF 1001 MB. THE SEMICIRCLE APPEARANCE
OF THE ASSOCIATED CLOUD PATTERN EARLIER OBSERVED DURING THE DAY
HAS DETERIORATED JUST OVER THE PAST FEW HOURS. DEEP CONVECTION
EARLIER NOTED HAS SINCE DIMINISHED WITH ONLY SCATTERED MODERATE
CONVECTION NOTED WITHIN 120 NM OF THE CENTER IN SE QUADRANT.
KRISTY IS STILL FORECAST TO TRACK NW OVER COOLER SEA SURFACE 
TEMPERATURES DURING THE NEXT 48 HRS AND GRADUALLY WEAKEN...
BECOMING A REMNANT LOW ON SUN. SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

A TROPICAL LOW PRES SYSTEM MOVING SW AT 10 KT IS JUST N OF THE 
MONSOON TROUGH NEAR 14N122W WITH AN ESTIMATED PRES AT 1007 MB. 
THIS LOW HAS CHANGED LITTLE IN PATTERN STRUCTURE OVER THE PAST
12-24 HRS AS IT REMAINS UNDER NE UPPER SHEAR...HOWEVER THE 
SURROUNDING ENVIRONMENTAL CONDITIONS ARE EXPECTED TO MORE 
FAVORABLE FOR THE LOW TO INTENSIFY INTO A TROPICAL DEPRESSION 
OVER THE NEXT COUPLE OF DAYS. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS WITHIN 150 NM OF THE LOW IN THE SW QUADRANT.

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

THE MONSOON TROUGH EXTENDS FROM 09N84W TO 08N96W TO 10N114W 
WHERE IT ENDS. IT CONTINUES AGAIN JUST SW OF THE LOW AT 14N122W 
TO 12N122W TO LOW PRES NEAR 13N134W AND TO 11N140W. SCATTERED 
STRONG CONVECTION IS  WITHIN 120 NM S OF THE TROUGH BETWEEN 
109W AND 114W.
...DISCUSSION...

IN THE UPPER LEVELS...LARGE SCALE MID/UPPER LEVEL RIDGING WITH 
AN ASSOCIATED MID/UPPER LEVEL ANTICYCLONE AT 20N130W COVERS
THE AREA EXCEPT IN THE FAR NW PORTION WHERE THE EASTERN EDGE OF
DEEP LAYER TROUGHING IS PRESENT.

AT THE SURFACE...A NEARLY STATIONARY SUBTROPICAL HIGH PRES 
CENTERED NEAR 38N142W EXTENDS A RIDGE SEWD THROUGH 32N129W AND 
TO NEAR 27N118W. HIGH RESOLUTION ASCAT DATA FROM YESTERDAY 
AFTERNOON SHOWED ENHANCED NE WINDS IN ENHANCE PRES GRADIENT N OF 
THE CONVERGENCE ZONE IN THE VICINITY OF THE LOW PRES NEAR 
15N120W AND ANOTHER ONE NEAR 13N134W. BROAD LOW PRES IS PRESENT 
OVER MUCH OF AREA S OF ABOUT 23N WHERE OUTSIDE KRISTY AND THE 
TROPICAL LOWS LIGHT TO MODERATE WINDS ARE NOTED. THE LOW NEAR 
14N122W IS PROGGED BY THE GLOBAL MODELS TO ACQUIRE SOME 
DEVELOPMENT OVER THE NEXT 48 HOURS...WITH THE GFS STILL BEING 
THE MORE AGGRESSIVE ONE WITH WINDS AND SEAS.

A TIGHT PRES GRADIENT OVER CENTRAL AND SE MEXICO IS RESULTING 
IN N-NE WINDS TO PULSATE AT 20-30 KT THROUGH THE CHIVELA PASS AND
THROUGH THE GULF OF TEHUANTEPEC. THESE WINDS ARE FORECAST TO 
DIMINISH TO 20 KT OR LESS BY SAT EVENING...THEN POSSIBLY COME
BACK SUN BUT AT LESS SPEEDS. NE-E WINDS ARE ALSO EXPECTED TO 
PULSE AT 15 TO 20 KT THROUGH THE GULF OF PAPAGAYO WITH MAX SEAS 
OF 7 FT JUST DOWNSTREAM OF THE GULF THROUGH SUN. STRONGEST GAP 
WINDS ARE EXPECTED TO OCCUR DURING THE LATE NIGHT HOURS THROUGH 
A FEW HOURS AFTER SUNRISE.  

$$
AGUIRRE