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AXPZ20 KNHC 302111
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE SEP 30 2014

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 2100 UTC.


...SPECIAL FEATURES... POST-TROPICAL CYCLONE RACHEL IS CENTERED NEAR 22.9N 117.5W AT 30/2100 UTC MOVING S AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 40 KT. NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE IMAGERY AT THIS TIME WITH RACHEL EXPECTED TO RAPIDLY SPIN DOWN AND EVENTUALLY DISSIPATE BY FRIDAY. SEE THE LAST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC FOR MORE DETAILS.

A 1007 MB LOW PRES LOCATED NEAR 15N101W REMAINS POORLY ORGANIZED AND EMBEDDED WITHIN THE MONSOON TROUGH AXIS. THE LOW IS IN A REGION WHERE 850 MB RELATIVE VORTICITY HAS BEEN ENHANCED BY ENERGY FROM TROPICAL WAVE PASSAGES DURING THE PAST FEW DAYS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED ACROSS A LARGE AREA FROM 11N TO 17N BETWEEN 94W AND 105W. GLOBAL MODELS CONTINUE TO INDICATE THE LOW PRESSURE AREA WILL SLOWLY ORGANIZE DURING THE NEXT SEVERAL DAYS AS IT MOVES TO THE W-NW PARALLELING THE WEST-CENTRAL COAST OF MEXICO. THE LOW PRESSURE HAS A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS. REGARDLESS OF TROPICAL CYCLONE FORMATION... THIS DISTURBANCE WILL LIKELY PRODUCE LOCALLY HEAVY RAIN ACROSS PORTIONS OF SOUTHERN MEXICO INCREASING THE POTENTIAL FOR FLASH FLOODING AND MUD SLIDES.


...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 13N92W ACROSS SOUTHERN MEXICO ALONG 92W INTO THE SW GULF OF MEXICO MOVING W AT 20 KT. THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING ALOFT WHICH IS EXPECTED TO BE ABSORBED INTO A LARGER AND BROADER 700 MB CYCLONIC CIRCULATION TO THE WEST CENTERED IN THE VICINITY OF THE SPECIAL FEATURES LOW. ISOLATED MODERATE CONVECTION IS FROM 10N TO 14N BETWEEN 89W AND 94W.


...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 08N78W TO A 1007 MB LOW PRES NEAR 15N101W TO 12N114W TO 13N124W TO 11N133W. THE ITCZ EXTENDS FROM 11N133W TO 11N140W. SCATTERED MODERATE CONVECTION IS FROM 04N TO 07N BETWEEN 84W AND 89W...AND FROM 08N TO 14N BETWEEN 108W AND 115W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 11N TO 17N BETWEEN 94W AND 105W.


...DISCUSSION... GLOBAL MODEL GUIDANCE SUGGESTS SUSTAINED SOUTHWESTERLY MONSOONAL FLOW TO THE SOUTH AND SOUTHWEST OF THE SPECIAL FEATURES LOW NEAR 15N101W GENERALLY FROM 08N TO 15N BETWEEN 100W AND 115W THROUGH THURSDAY. SW WINDS ARE FORECAST TO REMAIN NEAR 20 KT...AS GFS AND ECMWF GUIDANCE AT THIS TIME ARE IN AGREEMENT ON SLOW DEVELOPMENT OF THE POSSIBLE TROPICAL CYCLONE TO THE NORTH. HOWEVER...A BROAD AREA OF SEAS TO 11 FT ARE EXPECTED WITHIN THE MONSOONAL FLOW AS A LONG PERIOD SW SWELL TRAIN...CURRENTLY S OF 10N BETWEEN 100W AND 133W...PROPAGATES ACROSS THE FORECAST WATERS FROM THE SOUTH TOWARDS THE MEXICO AND CENTRAL AMERICAN COAST...REACHING THE CONTINENT BY MIDDAY WEDNESDAY.

$$ HUFFMAN

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