000
AXPZ20 KNHC 130916
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURE...
TROPICAL STORM KRISTY CENTERED NEAR 18.5N 108.5W 1002 MB AT 0900 
UTC MOVING WNW 9 KT WITH MAXIMUM SUSTAINED WINDS 45 KT WITH 
GUSTS TO 55 KT AND MINIMUM PRESSURE OF 1002 MB. KRISTY IS 
EXHIBITING TIGHT BANDING WRAPPING INTO THE CENTER MOST 
NOTICEABLY IN THE SE SEMICIRCLE. NUMEROUS STRONG CONVECTION IS 
FROM 15N-19N BETWEEN 106W AND 109W. 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...
MONSOON TROUGH FROM 9N85W TO 7N100W TO 9N112W. ITCZ FROM 11N134W 
TO 9N140W. SCATTERED MODERATE ISOLATED CONVECTION FROM 07N-10N 
BETWEEN 132W-138S.

...DISCUSSION...
MUCH THE DISCUSSION AREA IS DOMINATED BY A BROAD UPPER LEVEL 
RIDGE WITH AXIS EXTENDING FROM AN ANTICYCLONIC CIRCULATION 
CENTERED NEAR 18N115W TO 32N123W. MUCH OF 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. THE AREA OF SUBSIDENCE IS N OF 20N W 
OF 110W. AN INVERTED UPPER LEVEL TROUGH WITH AXIS FROM EL 
SALVADOR TO 5N92W.

HIGH PRES RIDGE IS LOCATED N OF 15N W OF 115W. LIGHT TO 
MODERATE WINDS PREVAIL OVER MOST OF THE REGION...EXCEPT ALONG 
THE SOUTHERN COAST OF MEXICO IN THE VICINITY OF TROPICAL STORM 
KRISTY. NE TRADES AROUND THE SOUTHERN PERIPHERY OF THE RIDGE TO 
20 KT FROM 15N-20N W OF 130W. NE WINDS 20-25 KT ARE FORECAST IN 
THE GULF OF TEHUANTEPEC THU NIGHT THEN DECREASE TO LESS THEN 20 
KT FRI NIGHT. SURFACE TROUGH FROM 17N117W TO 11N119W. SCATTERED 
MODERATE TO STRONG CONVECTION WITHIN 50 NM EITHER SIDE OF TROUGH 
N OF 15N. AN OTHER TROUGH ANALYZED FROM 16N129W TO 10N131W. 
SCATTERED MODERATE TO STRONG CONVECTION WITHIN 90 NM E AND 30 NM 
W OF TROUGH FROM 14N-15N.

$$
DGS