000
AXPZ20 KNHC 101626
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU OCT 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...
POST TROPICAL CYCLONE NARDA CENTERED AT 16.3N 129.1W AT 1500 UTC 
MOVING W OR 265 DEG AT 3 KT. MAXIMUM SUSTAINED WINDS ARE 25 
KT GUSTING TO 35 KT WITH A CENTRAL SURFACE PRESSURE OF 1009 MB. 
CURRENTLY ONLY ISOLATED CLUSTERS OF MODERATE CONVECTION ARE 
NOTED WITHIN 120 NM ACROSS THE NE QUADRANT AND 45 NM SW 
QUADRANT. NARDA CONTINUES TO ENCOUNTER MODEST SW WIND SHEAR AND 
HAS ENTERED A ZONE OF STABLE AND DRIER AIR PREVAILING TO THE N 
AND NW. THE REMNANT LOW OF NARDA HAS THUS BEGUN TO LOSE ITS 
TROPICAL CHARACTERISTICS AND WILL GRADUALLY WEAKEN FURTHER AS IT 
MOVES W-SW THE NEXT FEW DAYS...AROUND THE SOUTHERN PERIPHERY OF 
A LARGE RIDGE OF HIGH PRESSURE CENTERED TO THE NW. REFER TO THE 
LAST NARDA FORECAST ADVISORY UNDER WMO/AWIPS HEADERS WTPZ24 
KNHC/MIATCMEP4 FOR ADDITIONAL DETAILS. 

WELL DEFINED MID LEVEL CYCLONIC TURNING CONTINUES ACROSS THE 
TROPICAL WATERS TO THE SW OF ACAPULCO MEXICO...WHERE A 1009 MB  
SURFACE LOW PRES CENTER IS ESTIMATED ALONG THE MONSOON TROUGH 
NEAR 14.5N102.5W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 180 NM ACROSS THE NE SEMICIRCLE OF 
THE LOW. DESPITE THE STRONG CYCLONIC TURNING SEEN IN SATELLITE 
IMAGERY THE PAST 24 HOURS...SURFACE CONDITIONS HAVE YET TO 
REFLECT IMPROVED ORGANIZATION. COOLER AND SLIGHTLY DRIER AIR 
SPILLING SW OFF THE COAST OF MEXICO TO THE N AND NW OF THIS 
SYSTEM MAY BE CONTRIBUTING TO THIS. THIS BROAD CIRCULATION IS 
EXPECTED TO SHIFT W-NW TO NW OVER THE NEXT FEW DAYS...WHERE 
ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR GRADUAL 
INTENSIFICATION. NE WINDS 20-25 KT ARE EXPECTED TO PREVAIL 
ACROSS THE NW SEMICIRCLE OF THE SURFACE LOW AS IT SHIFTS 
NORTHWESTWARD...AND WILL YIELD SEAS 7-9 FT DURING THIS TIME. 
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE IN 
THE NEXT 48 HOURS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 08N76W TO 09.5N86W TO 09N91W TO LOW 
PRES AT 14.5N102.5W TO 11.5N115W TO 08N117W TO 07.5N126W...WHERE 
IT FRACTURES...THEN RESUMES FROM S OF NARDA NEAR 13N129W TO 
10N136W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON BEYOND 
10N140W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG 
CONVECTION NOTED N OF 03.5N E OF 81W. SCATTERED MODERATE  
ISOLATED STRONG WITHIN 120 NM EITHER SIDE OF TROUGH BETWEEN 83W 
AND 94W. SCATTERED MODERATE TO STRONG WITHIN 240 NM S OF TROUGH 
BETWEEN 98W AND 122W...AND FROM 12.5N TO 15.5N BETWEEN 114W AND 
121W. 

...DISCUSSION...
A DEEP LAYERED UPPER CYCLONE IS CENTERED OVER THE DESSERT SW OF 
THE U.S. WITH A UPPER TROUGH EXTENDING S THEN SW TO NEAR 
22N129W...WHILE A REINFORCING SHORTWAVE TO THE NW IS APPROACHING 
30N AS IT BEGINS TO DROP INTO THE BACKSIDE OF BROAD TROFFING 
DOMINATING MUCH OF THE N HALF OF THE DISCUSSION AREA. SHARP 
RIDGES PERSIST ON EITHER SIDE OF THIS TROUGH...CENTERED ON UPPER 
ANTICYCLONES NEAR 14N143W AND 20N100W. THE EASTERN MOST RIDGE 
EXTENDS W-SW TO 13N125W AND CONTINUES TO FAVORABLY VENTILATE 
CONVECTION ALONG AND NEAR THE MONSOON TROUGH. 

AT LOWER LEVELS...A 1029 MB HIGH IS CENTERED NEAR 37N145W WITH 
RIDGE EXTENDING SE TO NEAR 20N110W. THE DEEP LAYERED UPPER 
CYCLONE OVER THE SW U.S. SUPPORTS A COLD FRONT SWEEPING THROUGH 
NORTHERN BAJA CALIFORNIA FROM NEAR 31N113W TO 27N120W. OVERNIGHT 
ASCAT PASSES DEPICTED GALE FORCE SW WINDS OCCURRING WITHIN 90 NM 
TO THE S OF THIS FRONT WITHIN N PORTIONS OF THE GULF OF 
CALIFORNIA...A SOMEWHAT RARE OCCURRENCE. THESE WINDS WILL 
DIMINISH QUICKLY BY AFTERNOON TO LESS THAN 20 KT AS THE FRONT 
MOVES SLOWLY SE AND WEAKENS. NLY FLOW TO NEAR GALE FORCE IS 
OCCURRING ACROSS THE NEAR AND OFFSHORE WATERS OF CALIFORNIA WELL 
BEHIND THIS COLD FRONT...AND IS GENERATING N SWELL THIS HAS 
BEGUN TO MOVE INTO NE PORTIONS OF THE AREA. SEAS TO 8 FT AND 
GREATER WILL SHIFT SOUTHWARD ACROSS N PORTIONS OF THE AREA 
THROUGH SATURDAY...REACHING 15N BY SATURDAY MORNING BEFORE 
FADING. MODERATE TO FRESH NELY TRADES WILL PREVAIL TO THE N 
THROUGH NW OF THE REMNANTS OF NARDA DURING THE NEXT FEW DAYS AS 
STRONG HIGH PRESSURE DOMINATES THE NE PACIFIC. 

STRIPLING