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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 230944
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC TUE SEP 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...SPECIAL FEATURES...

A 1008 MB SURFACE LOW PRESSURE IS EMBEDDED IN THE MONSOON TROUGH 
NEAR 14N100W...AND IS MOVING WESTWARD ABOUT 12 KT. CONVECTION IS 
INTERMITTENT...AND CURRENTLY SCATTERED MODERATE TO STRONG 
CONVECTION IS OBSERVED S OF THE LOW CENTER WITHIN 60 NM EITHER 
SIDE OF LINE FROM 13N99W TO 12N103W. AN UPPER LEVEL ANTICYCLONE 
IS CENTERED OVER EXTREME NW MEXICO WITH ITS ANTICYCLONIC 
ENVELOPE COVERING THE DISCUSSION AREA N OF 12N BETWEEN 100-120W 
AND PROVIDING FAVORABLE ENVIRONMENTAL CONDITIONS FOR THIS 
SURFACE LOW TO GRADUALLY STRENGTHEN...WITH A HIGH POSSIBILITY OF 
TROPICAL CYCLONE FORMATION...AS THE LOW REACHES NEAR 12.5N102W 
1007 MB LATE TONIGHT...AND NEAR 14N106W AT 1005 MB LATE WED 
NIGHT. THE LOW...OR POSSIBLY TROPICAL CYCLONE SHOULD THEN BEGIN 
TO TRACK WNW WITH THE OFFICIAL GRIDS DEPICTING A 1003 MB LOW 
CENTER NEAR 16N109W LATE THU NIGHT. BY THEN WINDS WILL BE 
INCREASING TO 20-25 KT MAINLY OVER THE N SEMICIRCLE WITH SEAS 
BUILDING TO 8 FT. THEREAFTER THE 20-25 KT WIND FIELD WILL EXPAND 
OUTWARD INCREASING TO 20-30 KT DURING THE UPCOMING WEEKEND. 

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

THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHERN CARIBBEAN  
BETWEEN 08-10N FROM THE NW COAST OF COLOMBIA TO ACROSS COSTA 
RICA TO THE PACIFIC COAST OF COSTA RICA AT 10N86W CONTINUING W-
NW TO AN EMBEDDED 1008 MB LOW PRESSURE NEAR 14N100W. THE MONSOON 
TROUGH THEN TURNS ABRUPTLY SW TO 05N112W THEN NW TO 12N125W. 
SCATTEROMETER WINDS SUGGEST A ITCZ FORMS AT 14N130W AND 
CONTINUES SW TO BEYOND 10N140W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION HAS MOVED OFF THE 
COAST OF CENTRAL AMERICA WITHIN 60 NM EITHER SIDE OF A LINE FROM 
09N87W TO 14N91W. ISOLATED MODERATE TO STRONG CONVECTION IS 
OBSERVED WELL S OF THE MONSOON TROUGH WITHIN 120 NM EITHER SIDE 
OF A LINE FROM 06N79W TO 09N98W TO 07N112W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ALSO OBSERVED  
OVER AND WITHIN 60 NM OF COAST OF MEXICO FROM 18-22N. 

...DISCUSSION...   

THE REMNANTS OF FORMER TROPICAL CYCLONE POLO ARE ANALYZED AS A
1008 MB LOW PRESSURE NEAR 21.5N115.5W. WINDS HAVE DIMINISHED TO
15-20 KT WITHIN ABOUT 120 NM OF THE CENTER...WITH SEAS OF 5-7 FT.
THE LOW IS FORECAST TO MOVE SW TO NEAR 21N116.5W LATE TONIGHT
WITH WINDS DIMINISHING TO 10-15 KT WITHIN 120 NM ONLY OVER THE
WESTERN SEMICIRCLE. 

A REINFORCING UPPER SHORTWAVE TROUGH HAS MOVED SE OVER THE FAR 
NW PORTION OF THE DISCUSSION AREA...AND IS ACCOMPANIED BY DENSE 
UPPER MOISTURE. AN ASSOCIATED SURFACE COLD FRONT IS EXPECTED TO 
MOVE SE INTO THE NW WATERS LATER TODAY...AND CONTINUE E TO A 
LINE FROM 32N120W TO 25N130W LATE THU WHERE THE FRONT WILL WASH 
OUT. THE NORTHERLY FLOW BEHIND THE DISSIPATING FRONT IS EXPECTED 
TO INCREASE TO 15-20 KT ALONG THE PACIFIC COAST OF THE BAJA 
PENINSULA TO THE N OF 30N LATE THU...THEN SPREAD AS FAR S AS 26N 
BY LATE FRI. SEAS WILL BUILD TO 6-9 FT IN MIXING NW AND SE SWELL 
ACROSS THE WATERS N OF 26N WITHIN 120 NM W OF THE BAJA PENINSULA 
ON FRI AND SAT...WITH WINDS DIMINISHING TO 10-15 KT AND SEAS 
SUBSIDING TO 4-7 FT ON SUN.         

$$
NELSON



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Page last modified: Tuesday, 23-Sep-2014 09:44:58 UTC