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000
AXPZ20 KNHC 310311
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC.


...SPECIAL FEATURE...

MAJOR STRONG CATEGORY FOUR HURRICANE JIMENA IS CENTERED NEAR 15.0N 132.5W OR ABOUT 1524 MILES E OF HILO HAWAII AT 0300 UTC...MOVING WNW OR 290 DEG AT 14 KT. THE MAXIMUM SUSTAINED WIND SPEED IS 130 KT WITH GUSTS TO 160 KT AND ESTIMATED MINIMUM PRESSURE HAS DECREASED TO 936 MB. LATEST SATELLITE IMAGERY SHOWS THAT JIMENA HAS A DISTINCT 20 NM WIDE EYE. THE OVERALL CLOUD PATTERN WITH JIMENA HAS BECOME VERY SYMMETRICAL AND BETTER ORGANIZED DURING THE PAST 6-12 HOURS. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION SURROUNDS THE 10 NM WIDE EYE WITHIN 120 NM IN THE NE AND SW QUADRANTS...150 NM IN THE SE QUADRANT AND 90 NM IN NW QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SEEN IN BANDS ELSEWHERE WITHIN 300 NM NE AND 120 NM SW SEMICIRCLES OF THE THE CENTER...AND ALSO SSW OF JIMENA WITHIN 60 NM OF A LINE FROM 04N140W TO 07N132W TO 09N128W. JIMENA IS FORECAST TO TRACK ALONG THE WESTERN PERIPHERY OF A SUB-TROPICAL RIDGE THROUGH EARLY NEXT WEEK REACHING NEAR 17N139W BY TUE AFTERNOON. JIMENA IS PRODUCING A LARGE AREA OF 12 FT OR GREATER SEAS OUTWARD TO 290 NM N AND 240 NM S OF THE CENTER WITH SURROUNDING AREA TO 20-33 KT WINDS AND SEAS OF 8-11 FT ARE EXPECTED TO EXPAND TO ABOUT 300 SE AND 540 NM NW SEMICIRCLES OF THE CENTER BY TUE. 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 1008 MB LOW PRES SYSTEM IS EMBEDDED IN THE MONSOON TROUGH NEAR 11N108W...AND IS SLOWLY MOVING WESTWARD. SCATTERED MODERATE ISOLATED/STRONG CONVECTION IS WITHIN 60 NM OF THE LOW CENTER... AND WITHIN 240 NM IN THE SW QUADRANT. SIMILAR ACTIVITY IS IN BANDS WITHIN 60 NM OF A LINE FROM 13N105W TO 10N102W. LAST VISIBLE IMAGERY DEPICTED INCREASING BANDING FEATURES AROUND THE CENTER OF THE LOW. THE PRES GRADIENT HAS TIGHTENED E OF THE LOW ENHANCING THE SOUTHWESTERLY MONSOONAL FLOW TO 20-25 KT WITHIN 90 NM SE SEMICIRCLE OF THE CENTER WITH SEAS OF 7-9 FT. ELSEWHERE WITHIN 240 NM OF THE CENTER...WINDS ARE 10-20 KT WITH SEAS OF 5- 7 FT. THE LOW IS FORECAST TO REACH NEAR 12N112W BY EARLY MON EVENING...AND TO NEAR 15N115W BY EARLY TUE EVENING. EXPECT THE 20-25 KT WINDS TO GRADUALLY INCREASE TO 25-30 KT OVER THE NEXT 24-48 HOURS AS THE LOW BECOMES BETTER ORGANIZED ALONG WITH SEAS POSSIBLY BUILDING RATHER QUICKLY. CONDITIONS ARE FAVORABLE FOR A MEDIUM PROBABILITY OF TROPICAL CYCLONE FORMATION OF THE LOW OVER THE NEXT 48 HOURS AS JIMENA PULLS FURTHER TO THE W AND AWAY FROM IT.


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

THE MONSOON TROUGH AXIS EXTENDS WSW OFF THE PACIFIC COAST OF COSTA RICA AT 09N85W...AND GRADUALLY CONTINUES NW TO 11N94W TO 13N102W...THEN TURNS SW TO LOW PRES NEAR 11N108W TO 10N114W TO 11N118W WHERE IT LOSES IDENTITY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF THE TROUGH BETWEEN 85W- 90W AND BETWEEN 112W-115W. SCATTERED MODERATE CONVECTION IS FROM 08N-14N BETWEEN 97W-102W. ELSEWHERE SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF A LINE 07N113W TO 08N118W.

SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG AND WITHIN 60 NM OF THE COAST OF COSTA RICA AND NORTHERN PANAMA BETWEEN 82W-86W.


...DISCUSSION...

A SURFACE RIDGE EXTENDS SE FROM 32N136W TO 17N104W. THE GRADIENT IS SUPPORTING 15-20 KT TRADES ACROSS THE WATERS S OF THE RIDGE WITH COMBINED SEAS OF 6-8 FT IN MIXED NW AND CROSS EQUATORIAL S SWELL. LITTLE CHANGE EXPECTED THROUGH TUE THEN THESE CONDITIONS WILL SHIFT WESTWARD AS JIMENA CROSSES 140W ON WED. THE GRADIENT E OF THE RIDGE IS SUPPORTING NW 15-20 KT WINDS ACROSS THE SUBTROPICS E OF 122W TO THE BAJA CALIFORNIA PENINSULA WITH COMBINED SEAS OF 6-8 FT ACROSS THE DISCUSSION. THE GRADIENT WILL RELAX ON MON INTO TUE WITH SEAS SUBSIDING TO 4-7 FT BY TUE EVENING.

$$ AGUIRRE

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