000
AXPZ20 KNHC 162119
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
2205 UTC WED OCT 16 2013

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION PRISCILLA IS CENTERED NEAR 18.6N 120.3W AT 
16/2100 UTC MOVING WEST-NORTHWESTWARD OR 290 DEGREES AT 8 KT.   
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC 
FOR MORE DETAILS. PRISCILLA IS WEAKENING. THE REMAINING DEEP 
CONVECTION HAS VANISHED...AND NOW ONLY A SWIRL OF LOW CLOUDS IS 
ASSOCIATED WITH THE TROPICAL CYCLONE. AN EARLIER ASCAT PASS 
SHOWED PEAK SURFACE WINDS OF 20-25 KT MAINLY WITHIN 180 NM NW 
SEMICIRCLE OF THE CENTER OF PRISCILLA WHERE THE PRES GRADIENT 
TIGHTENS BETWEEN THE CYCLONE AND THE RIDGE TO THE NORTH. 
PRISCILLA IS FORECAST TO BECOME A REMNANT LOW IN ABOUT 24 HOURS 
AND DISSIPATE IN 72 HOURS. IT IS GOING TO BE MOVING INTO AN AREA 
OF DRIER AND MORE STABLE AIR...COLDER SEA SURFACE TEMPERATURE... 
AND INCREASING WIND SHEAR ALOFT.  

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

MONSOON TROUGH EXTENDS FROM 11N85W TO 09N92W TO 11N100W TO 1010 
MB LOW PRES NEAR 09N108W TO 10N120W TO 09N130W TO 08N140W. 
SCATTERED MODERATE CONVECTION IS FROM 08N TO 10N BETWEEN 84W AND 
91W. SIMILAR CONVECTION IS ALSO NOTED FROM 08N TO 11N BETWEEN 
128W AND 135W AND FROM 06N TO 08N W OF 136W.  

...DISCUSSION...                                                 
                 
ALOFT...A RIDGE/TROUGH PATTERN DOMINATES THE N WATERS. DRY AND 
STABLE AIR PREVAILS FROM 11N TO 22N W OF 125W AND OVER THE NE 
PART OF THE FORECAST AREA...INCLUDING MOST OF BAJA CALIFORNIA 
PENINSULA. A LARGE ANTICYCLONE CENTERED OVER THE GULF OF MEXICO 
EXTENDS A RIDGE ACROSS SOUTH-CENTRAL MEXICO INTO THE PACIFIC 
WATERS TO NEAR 110W...INDUCING EASTERLY FLOW ALOFT ACROSS THE 
WATERS E OF 100W. AN INVERTED UPPER LEVEL TROUGH IS JUST W OF 
THE RIDGE AND GOES FROM 21N109W TO 15N110W...SHIFTING W.

ELSEWHERE AT THE SURFACE...A RIDGE STRETCHES FROM NEAR 30N140W 
SE TOWARD THE SOUTHERN BAJA CALIFORNIA PENINSULA NEAR 25N112W. 
THE WEAK 1010 MB LOW PRES EMBEDDED IN THE MONSOON TROUGH NEAR 
09N108W IS ONLY PRODUCING LIGHT TO GENTLE WINDS AND LIMITED 
CONVECTION IS NOTED IN ITS VICINITY. FARTHER E...THERE IS A 
TROPICAL WAVE ALONG 87W N OF 10N WITH LIMITED SHOWER AND 
THUNDERSTORM ACTIVITY. VISIBLE SATELLITE IMAGERY REVEALS A SWIRL 
OF LOW CLOUDS ALONG THE WAVE AXIS NEAR 11.5N. AS THE WAVE MOVES 
WESTWARD AT 5 TO 10 KT...CONDITIONS ARE GRADUALLY EXPECTED TO 
BECOME CONDUCIVE FOR SLOW DEVELOPMENT. HOWEVER...NO DEVELOPMENT 
OF THIS LOW IS ANTICIPATED DURING THE NEXT 48 HOURS. 

RELATIVELY BENIGN MARINE CONDITIONS PREVAIL OUTSIDE OF THE 
EFFECTS OF PRISCILLA...WITH GENTLE TO MODERATE WINDS AND 4-7 FT 
SEAS DOMINATING MOST OF THE DISCUSSION AREA THROUGHOUT AT LEAST 
THE NEXT 48 HOURS. THE EXCEPTION WILL BE IN THE FAR W CENTRAL 
WATERS WHERE SCATTEROMETER DATA SHOW TRADE WINDS OF 15-20 KT 
WITH SEAS NEAR 8 FT. 
 
$$ 
GR