000
AXPZ20 KNHC 141550
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...

TROPICAL STORM KRISTY CENTERED NEAR 20.4N 112.9W AT 1500 UTC 
MOVING WNW AT 9 KT. MAXIMUM SUSTAINED WINDS 45 KT WITH GUSTS TO 
55 KT AND MINIMUM PRESSURE OF 998 MB. THE SYSTEM HAS SHOWN SIGNS 
OF BETTER ORGANIZATION OVER THE PAST 12-24 HOURS WITH THE CENTER 
PARTIALLY EXPOSED NEAR THE W EDGE OF DEEP CONVECTION. SCATTERED 
MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 150 NM OF THE 
CENTER EXCEPT IN THE SW QUADRANT. KRISTY IS 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.

TROPICAL LOW PRES IS EMBEDDED WITHIN THE MONSOON TROUGH NEAR 
15N119W AN ESTIMATED AT 1007 MB. SCATTERED MODERATE TO STRONG 
CONVECTION IS NOTED W OF THE LOW LEVEL CENTER WITHIN 120 NM OF 
14N122W. SCATTEROMETER DATA SHOWS 20-25 KT NE TO E WINDS WITHIN 
150 NM OF THE N QUADRANT...WITH SEAS 7 TO 8 FT. THIS SYSTEM MAY 
DEVELOP INTO A TROPICAL CYCLONE AS IT TRACKS SLOWLY W TO NEAR 
15N122W SAT...AND NEAR 15N125W SUN. 

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

THE MONSOON TROUGH AXIS EXTENDS FROM 08N83W TO 09N109W...THEN 
RESUMES FROM THE LOW PRES NEAR 15N119W TO LOW PRES NEAR 14.5N 
132W TO 12N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
IS WITHIN 90 NM EITHER SIDE OF AXIS E OF 109W...AND WELL W OF 
THE LOW CENTERED NEAR 14.5N132W...WITHIN 90 NM OF 13N138W. 

...DISCUSSION...

NEARLY STATIONARY SUBTROPICAL HIGH PRES CENTERED NEAR 38N141W 
EXTENDS A RIDGE SSW INTO THE NORTH-CENTRAL PORTION OF THE AREA. 
SCATTEROMETER DATA EARLIER THIS MORNING INDICATED ENHANCED NE 
WINDS N OF THE CONVERGENCE ZONE IN THE VICINITY OF LOWS EMBEDDED 
IN THE MONSOON TROUGH NEAR 15N119W AND 14.5N132W. FRESH TO STRONG
N WINDS ARE ALSO EVIDENT IN THE GULF OF TEHUANTEPEC BASED ON A 
0406 UTC ASCAT PASS. LIGHT TO MODERATE WINDS AND SEAS 6-7 FT 
PREVAIL ELSEWHERE ACROSS THE REGION.

GFS AND EUROPEAN GLOBAL MODELS ARE IN FAIRLY GOOD AGREEMENT. TS 
KRISTY IS EXPECTED TO MOVE NW THROUGH MON THEN DRIFT NW ON TUE.
GFS AND ECMWF HAVE NEARLY IDENTICAL TRACKS FOR THE LOW NEAR 15N 
119W...MOVING IT W INITIALLY THROUGH SUN...THEN W-NW THROUGH WED.
THE GFS INTENSIFIES THE LOW MORE AGGRESSIVELY THAN EITHER THE 
ECMWF AND UKMET MODELS...BUT THERE IS FAIRLY GOOD AGREEMENT THAT 
ENVIRONMENTAL CONDITIONS ARE FAVORABLE...AND INTENSIFICATION IS 
LIKELY TO OCCUR THROUGH THE WEEKEND.

A SURFACE RIDGE OVER THE SW GULF OF MEXICO IS CAUSING NORTHERLY 
WINDS TO PULSE WITH A STRONG DIURNAL SIGNAL AT 20 TO 25 KT WITH 
SEAS TO 8 FT INTO AND JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
WITH LITTLE CHANGE EXPECTED THROUGH SUN. NE TO 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.  

$$
MUNDELL