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Eastern Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 301547
TWDEP 

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

...SPECIAL FEATURES...                                     
RACHEL WAS DOWNGRADED TO A TROPICAL DEPRESSION AT 30/1500 UTC. 
AT THIS TIME...IT IS CENTERED NEAR 23.1N 117.5W. THE DEPRESSION 
IS NEARLY STATIONARY...AND A VERY SLOW WEST-SOUTHWESTWARD MOTION 
IS EXPECTED OVER THE NEXT COUPLE OF DAYS. ESTIMATED MINIMUM 
CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WINDS HAVE 
DECREASED TO 30 KT GUSTS 40 KT. CONTINUED WEAKENING IS FORECAST 
DURING THE NEXT 48 HOURS...AND RACHEL IS LIKELY TO BECOME A 
REMNANT LOW LATER TODAY. RACHEL HAS LOST ALL ITS DEEP 
CONVECTION. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP3/WTPZ23 FOR MORE DETAILS.

A 1008 MB LOW PRES LOCATED NEAR 15N100W REMAINS POORLY ORGANIZED 
ALONG THE MONSOON TROUGH ROUGHLY 125 NM S OF ACAPULCO MEXICO. 
THIS IS IN THE AREA WHERE VORTICITY HAS BEEN ENHANCED BY A PAIR 
OF TROPICAL WAVE PASSAGES. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED MAINLY WITHIN 90NM SE AND NW QUADRANTS OF 
LOW CENTER. GLOBAL MODELS CONTINUE TO INDICATE THAT THIS BROAD 
LOW PRES AREA WILL SLOWLY BECOME BETTER ORGANIZED OVER THE NEXT 
SEVERAL DAYS AS IT DRIFTS TO THE WNW PARALLELING THE COAST OF 
MEXICO. THE LOW PRES HAS A MEDIUM CHANCE OF DEVELOPING INTO A 
TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS AND A HIGH CHANCE OF 
DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 3 TO 5 DAYS. 
REGARDLESS OF TROPICAL CYCLONE FORMATION...THIS DISTURBANCE WILL 
LIKELY PRODUCE LOCALLY HEAVY RAIN OVER PORTIONS OF SOUTHERN 
MEXICO THAT COULD CAUSE FLASH FLOODING AND MUD SLIDES.

...TROPICAL WAVES...                                            
A TROPICAL WAVE MOVING ACROSS THE YUCATAN PENINSULA AND 
GUATEMALA EXTENDS INTO THE EPAC TO NEAR 11N90W. SCATTERED 
MODERATE CONVECTION IS OBSERVED ON SATELLITE IMAGERY WHERE THE 
WAVE AXIS MEETS THE MONSOON TROUGH. THE WAVE WILL CONTINUE TO 
MOVE WESTWARD REACHING THE GULF OF TEHUANTEPEC ON WED.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
MONSOON TROUGH EXTENDS FROM 10N85W TO 1008 MB LOW PRES LOCATED 
NEAR 15N100W TO 12N114W. ITCZ CONTINUES FROM 12N114W TO 12N125W 
TO 11N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
NOTED FROM 10N TO 13N BETWEEN 88W AND 92W. SCATTERED MODERATE 
CONVECTION IS FROM 09N TO 13N BETWEEN 110W AND 114W.

...DISCUSSION...                                            
MARINE GUIDANCE SUGGESTS INCREASING SW WIND FLOW S OF THE 
MONSOON TROUGH AXIS BETWEEN 100W AND 115W LATE TONIGHT THROUGH 
THU IN ASSOCIATION WITH TROPICAL LOW PRES FORECAST TO DEVELOP 
LATER THIS WEEK. SEE SPECIAL FEATURES FOR DETAILS. EXPECT SW 
WINDS OF 20-25 KT AND BUILDING SEAS OF 8-10 FT FROM 09N TO 12N 
BETWEEN 98W AND 111W BY WED MORNING...AND FROM 09N TO 14N 
BETWEEN 100W AND 110W...AND ALSO FROM 08N TO 11N BETWEEN 110W 
AND 114W BY THU MORNING.

SEAS TO 12 FT ARE STILL NOTED WITHIN 40 NM NW QUADRANT OF RACHEL 
LIKELY DUE TO THE PRES GRADIENT BETWEEN THE TROPICAL CYCLONE AND 
A RIDGE DOMINATING THE N WATERS MAINLY N OF 15N W OF 122W.

CLUSTERS OF MODERATE TO STRONG CONVECTION HAVE DEVELOPED NEAR 
THE SOUTHERN END OF A TROUGH EXTENDING OVER WESTERN MEXICO. THIS 
CONVECTION COVERS THE AREA FROM 18N TO 22N E OF 107W TO THE 
MEXICAN COAST.

LONG PERIOD CROSS EQUATORIAL SW SWELL WILL CONTINUE TO SPREAD 
ACROSS THE SOUTH CENTRAL WATERS DURING THE NEXT FEW DAYS. THIS 
SWELL EVENT WILL COMBINE WITH SW WIND WAVES GENERATED SOUTH OF 
THE MONSOON TROUGH PREVIOUSLY MENTIONED...RAISING SEAS TO 9 FT S 
OF A LINE S OF A LINE FROM 03.4N90W TO 12N100W TO 12N120W TO 
00N135W BY WED MORNING.

$$
GR

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Page last modified: Tuesday, 30-Sep-2014 15:47:54 UTC