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000
AXPZ20 KNHC 311553
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON AUG 31 2015

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 1545 UTC.


...SPECIAL FEATURES...

HURRICANE JIMENA IS CENTERED NEAR 15.6N 135.3W OR ABOUT 1330 MILES E OF HILO HAWAII AT 1500 UTC. JIMENA IS MOVING W OR 280 DEG AT 14 KT AND IS FORECAST TO SLOW SOME OVER THE NEXT COUPLE OF DAYS AS THE CENTER REACHES THE W PERIPHERY OF A SUB-TROPICAL RIDGE. ESTIMATED MINIMUM CENTRAL PRESSURE IS 936 MB. THE MAXIMUM SUSTAINED WINDS ARE 130 KT WITH GUSTS TO 160 KT AND JIMENA IS FORECAST TO GRADUALLY WEAKEN.

CURRENTLY NUMEROUS MODERATE TO STRONG CONVECTION SURROUNDS A 20 NM DIAMETER EYE...WITHIN 120 NM NE SEMICIRCLE AND WITHIN 90 NM OVER THE SW SEMICIRCLE. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ELSEWHERE WITHIN 390 NM NE AND 210 NM SW SEMICIRCLES OF CENTER. JIMENA IS PRODUCING A LARGE AREA 12 FT OR GREATER SEAS OUTWARD TO 480 NM N AND 270 NM S OF THE CENTER. THE SURROUNDING AREA TO 20-33 KT WINDS IS NEARLY CONCENTRIC WITH THE RADIUS OF 12 FT OR GREATER SEAS. REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC AND HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFEPI/FZPN02 KWBC FOR ADDITIONAL DETAILS.

A 1007 MB SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 10.5N109W AND IS MOVING SLIGHTLY N OF DUE W AT ABOUT 5 KT. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 180 NM OF THE CENTER WITH INTERMITTENT BANDING. THE GRADIENT IS THE TIGHTEST E OF THE LOW ENHANCING THE SOUTHWESTERLY MONSOONAL FLOW TO 20-25 KT WITHIN ABOUT 180 NM OVER THE E SEMICIRCLE WITH COMBINED SEAS OF 7-9 FT. CONDITIONS ARE FAVORABLE FOR TROPICAL FORMATION AS THIS LOW BEGINS TO MOVE NW REACHING NEAR 13N111W ON TUE AND NEAR 16N113W ON WED.


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

THE MONSOON TROUGH EXTENDS W OFF THE PACIFIC COAST OF COSTA RICA AT 10N86W TO AN EMBEDDED 1009 MB SURFACE LOW PRES AT 10N89W WITH THE TROUGH THEN CONTINUING SW TO 09N96W...THEN TURNS NW TO 12N105W...THEN SW THROUGH A 1007 MB SURFACE LOW AT 10.5N109W... WITH THE MONSOON TROUGH THEN CONTINUING W TO 11N124W WHERE IT LOSES IDENTITY IS THE BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL CYCLONE JIMENA.

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 270 NM OVER THE NW SEMICIRCLE OF THE EMBEDDED LOW AT 10N89W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED OVER AND S OF THE MONSOON TROUGH WITHIN 150 NM EITHER SIDE OF A LINE FROM 05N78W TO 07N99W...AND WITHIN 180 NM EITHER SIDE OF A LINE FROM 09N113W TO 07N126W. SIMILAR CONVECTION IS OBSERVED S OF JIMENA WITHIN 90 NM EITHER SIDE OF A LINE FROM 15N128W TO 06N140W AND ALSO WITHIN 75 NM OF 13.5N98W.


...DISCUSSION...

A SURFACE RIDGE EXTENDS SE FROM 32N132W TO 19N110W. THE GRADIENT IS SUPPORTING 15-20 KT TRADES ACROSS THE WATERS S OF THE RIDGE TO ALONG 23N WHERE THE TRADES GRADUALLY INCREASE IN ASSOCIATION WITH CYCLONE JIMENA. LITTLE CHANGE EXPECTED THROUGH EARLY TUE THEN THESE CONDITIONS WILL SHIFT WESTWARD AS JIMENA CROSSES 140W ON TUE EVENING. THE GRADIENT E OF THE RIDGE IS SUPPORTING NW 15- 20 KT WINDS ACROSS THE SUBTROPICS N OF 27N E OF 123W TO THE BAJA CALIFORNIA PENINSULA WITH COMBINED SEAS OF 6-8 FT ACROSS THE DISCUSSION AREA. THE GRADIENT WILL RELAX TONIGHT INTO EARLY TUE WITH SEAS SUBSIDING TO 4-6 FT BY MIDDAY WED.

$$ NELSON

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