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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 230947
TWDEP 

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

...SPECIAL FEATURES... 

BROAD CYCLONIC CIRCULATION IS ANALYZED AS A 1008 MB SURFACE LOW 
NEAR 09N128W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
REMAINS UNORGANIZED WITHIN 270 NM EITHER SIDE OF A LINE FROM 
13N120W TO 07N133W. THE GRADIENT N OF THE LOW AND S OF A 
SUBTROPICAL RIDGE IS MAINTAINING NE-E 20-25 KT WINDS ACROSS THE 
WATERS FROM 11-15N BETWEEN 125-130W WITH SEAS OF 9-11 FT. THE 
LOW HAS THE POTENTIAL TO BECOME A TROPICAL CYCLONE AS IT REACHES 
NEAR 12N131W LATE TONIGHT AND NEAR 14N135W ON SUN NIGHT. THE 
LOW...OR POSSIBLE TROPICAL CYCLONE...IS EXPECTED TO MOVE W 
THROUGH MOST OF NEXT WEEK WITH THE STRONG EASTERLY WINDS OVER 
THE N SEMICIRCLE. 

A 1008 MB LOW IS ANALYZED AT 07N138W WITH SCATTERED MODERATE  
ISOLATED STRONG CONVECTION OBSERVED WITHIN 90 NM EITHER SIDE OF 
A LINE FROM 05N132W TO BEYOND 04N140W. ALTHOUGH E WINDS ARE ONLY 
15-20 KT OVER THE N SEMICIRCLE OF THE LOW...THERE IS SOME 
POTENTIAL FOR TROPICAL CYCLONE FORMATION AS THE LOW REACHES NEAR 
07N140W TONIGHT AND THEN CONTINUES W OF THE AREA ON SUN.   

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

A LOW LEVEL TROUGH EXTENDS SW FROM THE PACIFIC COAST OF COSTA 
RICA AT 10N TO 07N96W WHERE SCATTEROMETER WINDS INDICATE THAT 
THE ITCZ FORMS...THEN WIGGLES WNW TO 10N122W WHERE THE ITCZ IS 
INTERRUPTED BY THE BROAD CYCLONIC FLOW ASSOCIATED WITH TWO 
SURFACE LOWS PREVIOUSLY MENTIONED. EXCEPT AS ALREADY MENTIONED 
IN ASSOCIATION WITH THE SURFACE LOWS...SCATTERED MODERATE 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 300 NM EITHER SIDE OF 
A LINE FROM 04N87W TO 05N110W TO 10N117W. 

A 1009 MB SURFACE LOW IS ANALYZED OVER NORTHERN COLOMBIA AT 
09N74W WITH A TROUGH EXTENDING SW FROM 05N77W TO 03N82W... WITH 
SCATTERED MODERATE CONVECTION FLARING WITHIN 150 NM OF THE
TROUGH AXIS.

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 
180 NM OF THE COAST OF CENTRAL AMERICA AND MEXICO FROM 90-100W. 

...DISCUSSION...

AN UPPER CYCLONE OVER SOUTHERN NEVADA TRAILS AN UPPER TROUGH 
ACROSS THE DISCUSSION AREA FROM 32N115W TO 22N122W. AN UPPER 
ANTICYCLONE IS CENTERED OVER THE TROPICS NEAR 13N115W WITH AN 
UPPER RIDGE EXTENDING W TO BEYOND 13N140W. ADDITIONALLY A KELVIN 
WAVE IS SHIFTING E ACROSS THE WESTERN PORTION OF THE DISCUSSION 
AREA...AND COMBINES WITH THE UPPER DIFFLUENCE ALONG THE UPPER 
RIDGE TO ENHANCE THE CONVECTION NEAR THE TROPICAL SURFACE LOWS 
PREVIOUSLY DESCRIBED. SOME OF THE DEBRIS MOISTURE FROM THIS 
CONVECTION CONCENTRATES INTO A 660 NM WIDE TROPICAL PLUME THAT 
IS ADVECTED NE AHEAD OF THE PREVIOUSLY DESCRIBED UPPER TROUGH... 
AND ACROSS THE SOUTHERN GULF OF CALIFORNIA AND NORTHERN 
MEXICO...EVENTUALLY FEEDING INTO SIGNIFICANT CONVECTION OVER 
TEXAS. 

A SURFACE RIDGE EXTENDS FROM 32N133W TO 16N104W. TO THE NE OF 
THE RIDGE ARE NW WINDS AT 15-20 KT ALONG THE PACIFIC COAST OF 
THE BAJA PENINSULA WITH COMBINED SEAS OF 4-6 FT. THE GRADIENT 
WILL TIGHTEN SOME TONIGHT SUPPORTING 20-25 KT NW FLOW BRIEFLY 
ACROSS THE EPAC WATERS FROM 25-28N E OF 115W TO THE BAJA COAST. 
THE GRADIENT WILL ALSO INCREASE SW OF THE RIDGE...AND E OF A 
COLD FRONT MOVING THROUGH THE HAWAIIAN ISLANDS...WITH SE WINDS 
INCREASING TO 20-25 KT ACROSS THE DISCUSSION WATERS N OF 23N W 
OF 135W TONIGHT THROUGH SUN NIGHT...WITH SEAS BUILDING TO 7-10 
FT. THE GRADIENT WILL RELAX ON MON AS THE WEAKENING FRONT MOVES 
INTO THE AREA ACCOMPANIED BY A SE-S-SW 15-20 KT WIND SHIFT AND 
MODERATE CONVECTION.  

LONG PERIOD SW SWELL AT 13-18 SECONDS OBSERVED ACROSS THE 
DISCUSSION AREA S OF 25N WILL CONTINUE N REACHING ALONG 32N 
TONIGHT AND CONTINUE THROUGH EARLY NEXT WEEK. 

GULF OF PAPAGAYO...EXPECT A BRIEF NE-E 20-25 KT SURGE EARLY 
TODAY THAT WILL BUILD SEAS TO 8 FT. THESE ENHANCED SEAS WILL 
PROPAGATE W AND MIX WITH LONG PERIOD CROSS-EQUATORIAL SW SWELL 
ACROSS THE PACIFIC WATERS FROM 09-12N BETWEEN 88-93W TODAY AND 
SUBSIDE TO 5-7 FT TONIGHT. 

GULF OF TEHUANTEPEC...EXPECT A BRIEF SURGE OF 20-25 KT NORTHERLY 
WINDS AT SUNRISE TODAY. 

$$ 
NELSON


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Page last modified: Saturday, 23-May-2015 09:47:46 UTC