000
AXPZ20 KNHC 140316
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI SEP 14 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 CENTERED NEAR 19.7N 111.1W AT 0300 UTC 
MOVING WNW AT 9 KT WITH MAXIMUM SUSTAINED WINDS OF 45 KT WITH 
GUSTS TO 55 KT AND MINIMUM PRESSURE OF 1000 MB. SATELLITE IMAGES 
SHOW THAT THE CYCLONE REMAINS PARTIALLY EXPOSED UNDER N-NW UPPER 
SHEAR. THE DENSEST OF THE CLOUD SHEAR PATTERN TO THE E AND SE OF 
THE CENTER. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
WITHIN 120 NM OF THE CENTER IN THE SE QUADRANT. KRISTY IS 
FORECAST TO TRACK IN A GENERAL NW DIRECTION OVER COOLER SEA 
SURFACE TEMPERATURES DURING THE NEXT 48 HRS CAUSING KRISTY TO 
UNDERGO GRADUAL WEAKENING. 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  09N84W TO 07N95W TO 08N115W
WHERE IT ENDS. IT THEN RESUMES AT 13N119W TO 12N127W. THE ITCZ 
BEGINS AT 10N138W AND CONTINUES TO BEYOND 09N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE 
MONSOON TROUGH E OF 88W.

...DISCUSSION...

IN THE MID/UPPER LEVELS...A HIGHLY AMPLIFIED PATTERN IS DEPICTED 
BY A LARGE ANTICYLONE OVER THE CENTRAL PORTION OF THE DISCUSSION
AREA WITH ITS MEAN AXIS ROUGHLY ALONG 123W WITH A CREST TO WELL 
NNE OF THE REGION. TO ITS W OVER THE CENTRAL PACIFIC IS A LARGE 
TROUGH THAT STRETCHES FROM 32N143W SSW TO NEAR 19N144W. MODERATE 
SUBSIDENCE RESULTING IN RATHER DRY AND STABLE ENVIRONMENTAL 
CONDITIONS DEPICTED BY BROKEN STRATOCUMULUS CLOUDS MOVING WSW 
COVERS THE REGION UNDER THE SUBSIDENCE AREA TO THE N AND NW OF 
THE TROPICAL ZONE. THE MID/UPPER LEVEL RIDGE FEATURE IS FORECAST
TO HOLD THROUGH THE NEXT 48 HRS...WITH THE TROUGH DEVELOPING
A LOW JUST NW OF THE AREA.

AT THE SURFACE...A 1011 MB LOW IS SW OF TROPICAL STORM KRISTY
NEAR 15N118W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
WITHIN 150 NM OF THE LOW IN THE SW QUADRANT. THE LOW IS EXPECTED 
TO MOVE SLOWLY W THROUGH THE NEXT 48 HRS WITH A POSSIBILITY OF
STRENGTHENING INTO A TROPICAL CYCLONE. AN ELONGATED A AREA OF 
LOW PRES HAS FORMED OVER THE WESTERN PORTION OF THE AREA FROM 
10N TO 16N BETWEEN 130W-135W WITH A WEAK 1011 MB LOW AT 13N133W.
CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE NOTED. 
THE GLOBAL MODELS SUGGEST THAT THIS LOW WILL REMAIN NEARLY 
STATIONARY
AGGRESSIVE IN FORECASTING WINDS AND SEAS WITH THIS FEATURE. WILL 
LEAN TOWARDS THE LESS AGGRESSIVE MODEL CONSENSUS FOR NOW...AND 
WAIT FOR UPDATED MODEL RUNS BEFORE MAKING A MORE DEFINITIVE 
FORECAST WITH RESPECT TO WINDS AND SEAS RELATED TO THIS LOW PRES 
SYSTEM.

A 1027 MB HIGH N OF THE DISCUSSION AREA AT 39N141W EXTENDS A
RIDGE SE THROUGH 32N134W AND TO NEAR 24N115W. LIGHT TO MODERATE 
WINDS PREVAIL OVER MOST OF THE REGION...EXCEPT WITHIN 300 NM N 
OF THE CONVERGENCE ZONE W OF 130W IN ENHANCED NE TRADE WIND 
FLOW...AND JUST W OF THE GULF OF PAPAGAYO IN FRESH E-NE GAP 
WINDS FUNNELING FROM THE W CARIBBEAN THROUGH CENTRAL 
AMERICA...BUILDING SEAS DOWNWIND FROM THE GULF OF PAPAGAYO TO 
AROUND 7 FT.

FRESH NE WINDS WITH SEAS AROUND 7 FT ARE EXPECTED TO PERSIST N 
OF THE CONVERGENCE ZONE W OF 130W THROUGH FRI. FRESH WINDS AND 
HIGHER SEAS ARE EXPECTED TO PERSIST DOWNSTREAM OF THE GULF OF 
PAPAGAYO THROUGH FRI EVENING. GFS AND ECMWF MODELS CONTINUE
TO INDICATE DIURNAL PULSES OF NORTHERLY DRAINAGE FLOW INTO THE 
GULF OF TEHUANTEPEC BEGINNING EARLY FRI...AND CONTINUING INTO 
SAT WITH N-NE WINDS OF 20-30 KT PRIMARILY AROUND DAYBREAK. SEAS 
THERE SHOULD REMAIN 8 FT OR LESS DOWNWIND FROM THE GULF OF 
TEHUANTEPEC.

$$
AGUIRRE