000
AXPZ20 KNHC 130242
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU SEP 13 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 FEATURE...
TROPICAL STORM KRISTY WAS CENTERED NEAR 18.0N 107.9W 1005 MB AT 
0300 UTC MOVING NW AT 8 KT WITH MAXIMUM SUSTAINED WINDS 45 KT
WITH GUSTS TO 55 KT AND MINIMUM PRESSURE OF 1005 MB. KRISTY IS 
EXHIBITING TIGHT BANDING WRAPPING INTO THE CENTER MOST 
NOTICEABLY IN THE SE SEMICIRCLE. SCATTERED STRONG CONVECTION IS 
WITHIN 90 NM OF THE CENTER IN THE SE QUADRANT. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM OF THE 
CENTER IN THE SW QUADRANT...AND WITHIN 30 NM OF 12N110W. KRISTY 
IS FORECAST TO SLOWLY INTENSIFY AS IT MOVES NW OVER THE NEXT 48
HOURS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

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

THE MONSOON TROUGH EXTENDS FROM 09N85W TO 08N96W TO 10N108W
TO 15N115W WHERE LOW LEVEL WINDS SUGGEST THE ITCZ BEGINS AND 
CONTINUES TO 08N140W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS WITHIN 120 NM S OF THE ITCZ W OF 136W.

...DISCUSSION...

THE AREA IS UNDER SUBSIDENCE ALOFT WITH DRY AND STABLE CONDITIONS
...WITH THE EXCEPTION OF THE SE AND FAR S AND SW PORTIONS WHERE
VERY DEEP MOISTURE THROUGH THE ATMOSPHERE IS NOTED ESPECIALLY 
OVER AND NEAR TROPICAL STORM KRISTY. A HIGH PRES SYSTEM LOCATED 
N OF THE AREA AT 42N139W 1032 MB EXTENDS A RIDGE SEWD THROUGH 
32N130W TO 27N118W. LIGHT TO MODERATE WINDS PREVAIL OVER MOST OF 
THE REGION...EXCEPT ALONG THE SOUTHERN COAST OF MEXICO IN THE 
VICINITY OF TROPICAL STORM KRISTY...AND WITHIN 300 NM N OF THE 
ITCZ W OF ABOUT 131W IN ENHANCED NE TRADE WIND FLOW AS REVEALED 
BY AN ASCAT PASS FROM 1526 UTC. SIMILAR WINDS ARE ALSO FOUND 
JUST W OF THE GULF OF PAPAGAYO IN FRESH TO STRONG E-NE GAP WINDS 
FUNNELING FROM THE WESTERN CARIBBEAN THROUGH CENTRAL AMERICA 
...BUILDING SEAS IN THE GULF OF PAPAGAYO TO AROUND 8 FT. THESE 
WINDS ARE FORECAST TO DIMINISH TO 20 KT OR LESS WITH SEAS LESS 
THAN 8 FT ON THU.

FRESH NE WINDS WITH SEAS IN THE RANGE OF 6-8 FT ARE EXPECTED TO 
PERSIST N OF THE CONVERGENCE ZONE W OF 130W THROUGH FRI. WINDS 
AND SEAS ARE EXPECTED TO DIMINISH DOWNSTREAM OF THE GULF OF 
PAPAGAYO LATE TONIGHT AND THU...THEN INCREASE AGAIN FRI MORNING. 
N-NE WINDS OF 20-25 KT THROUGH THE GULF OF TEHUANTEPEC ARE 
FORECAST TO DIMINISH TO 20 KT OR LESS IN ABOUT 12 HOURS...BUT 
INCREASE AGAIN TO 20-30 KT ON FRI WITH SEAS BUILDING TO 8 FT.

IN THE LONG TERM...THE LATEST GFS MODEL RUNS SPINS UP LOW
PRES NEAR 13N130W FRI INTO SAT WHICH MOVES NORTHWARD THROUGH THE 
WEEKEND. HOWEVER THE ECMWF AND UKMET MODELS SHOW LITTLE CHANCE 
FOR CYCLOGENESIS IN THIS AREA AND MOVE THE DISTURBANCE WNW IN 
THE TRADE WIND FLOW. WILL MAINTAIN PREVIOUS FORECASTER THINKING
OF WEAKER SOLN WITH LOW DEVELOPMENT FOR NOW...AND WAIT FOR FUTURE
MODELS RUNS TO MAKE ADJUSTMENTS TO FORECAST AS NECESSARY WITH
THIS FEATURE.

$$
AGUIRRE