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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 032201
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC FRI JUL 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC. 

...SPECIAL FEATURES... 

SHOWER AND THUNDERSTORM ACTIVITY AROUND A 1008 MB LOW PRES IS 
CENTERED NEAR 06N119W HAS BECOME BETTER DEVELOPED. THE LOW 
FORMED ALONG A WELL DEFINED TROPICAL WAVE IN A LARGE AREA OF 
CONVECTION THAT HAS BEEN FAIRLY PERSISTENT FOR THE PAST COUPLE 
OF DAYS ALONG THE ITCZ BETWEEN 115W AND 125W. AN UPPER 
ANTICYCLONE HAS FORMED NE OF THE LOW LEVEL CENTER IN THE 
CONTINUOUS OUTFLOW OF THESE THUNDERSTORMS. THE LOW LEVEL CENTER 
IS SOMEWHAT EXPOSED CURRENTLY WITH WEAK EASTERLY SHEAR...BUT 
CONVECTION IS EXPECTED TO PERSIST AND TROPICAL CYCLONE 
DEVELOPMENT IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS THE LOW 
MOVES SLOWLY W-NW. 

A 1006 MB LOW IS CENTERED NEAR 12N138W MOVING SLOWLY NW. AN 18 
UTC ASCAT PASS INDICATED FRESH WINDS N THE E AND NW QUADRANTS OF 
THE LOW PRES. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 
NM IN THE SE QUADRANT OF THE CENTER AS WELL. WHILE CONVECTION IS 
NOT EXTENSIVE...THE LOW IS IN AN AREA OF LOW ENVIRONMENTAL SHEAR 
AND CONDITIONS ARE FAVORABLE FOR POSSIBLE TROPICAL CYCLONE 
DEVELOPMENT OVER THE NEXT COUPLE OF DAYS AS THE LOW CONTINUES TO 
DRIFT SLOWLY NW.

...TROPICAL WAVES...                                     
TROPICAL WAVE ALONG 92W/93W N OF 10N MOVING W AT 10 TO 15 KT. NO 
SIGNIFICANT CONVECTION NOTED.

TROPICAL WAVE ALONG 108W/109W FROM 08N TO 14N MOVING W AT 10 TO 
15 KT. THE WAVE COINCIDES WITH BROAD 700 MB GLOBAL MODEL 
INDICATED TROUGHING AND AN 850 MB RELATIVE VORTICITY MAXIMUM 
BETWEEN 104W AND 109W. SCATTERED MODERATE CONVECTION IS FROM 03N 
TO 09N BETWEEN 103W AND 108W.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM 07N78W TO 05N80W TO 07N90W. THE 
ITCZ EXTENDS FROM 07N90W TO 09N115W...AND FROM LOW PRES NEAR 
06N119W 1008 MB TO 09N130W. SCATTERED MODERATE CONVECTION NOTED 
WITHIN 60 NM EITHER SIDE OF MONSOON TROUGH BETWEEN 80W AND 85W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 150 
NM EITHER SIDE OF ITCZ BETWEEN 95W AND 110W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION NOTED WITHIN 270 NM NW SEMICIRCLE. 

...DISCUSSION...                                                
N OF 15N E OF 120W...A RELATIVELY TIGHT PRES GRADIENT IS IN 
PLACE BETWEEN 1005 MB LOW PRES IN THE LOWER COLORADO RIVER 
VALLEY AND WEAK 1017 MB HIGH PRES W OF THE AREA IS ENOUGH TO 
ALLOW FRESH TO STRONG NW WINDS ALONG THE COAST OF BAJA 
CALIFORNIA FROM CABO SAN LAZARO TO PUNTA EUGENIA. THIS IS 
EXPECTED TO DIMINISH TONIGHT AS THE GRADIENT WEAKENS...AND SEAS 
WILL REMAIN LESS THAN 8 FT. FARTHER SOUTH...A SMALL UPPER LOW 
CENTERED NEAR 13N98W IS SUPPORTING A FEW SHOWERS AND 
THUNDERSTORMS TO ITS SOUTH FROM 10N TO 14N BETWEEN 97W AND 103W. 
AN EARILER PULSE OF STRONG GAP WINDS THROUGH THE GULF OF 
TEHUANTEPEC HAS DIMINISHED AS NOTED IN A RECENT SHIP 
OBSERVATIONS. RECENT SCATTEROMETER AND ALTIMETER PASSES INDICATE 
LIGHT TO MODERATE WINDS AND SEAS OF 3 TO 5 FT OVER OPEN WATERS 
ELSEWHERE N OF 15N E OF 120W.

S OF 15N E OF 110W...STRONG TRADE WIND FLOW OVER THE SW 
CARIBBEAN CONTINUES TO PRODUCE STRONG GAP WINDS INTO THE GULF OF 
PAPAGAYO AND OTHER AREAS ALONG THE NICARGAGUAN COAST. THE MAIN 
PULSES ARE OCCURRING OVERNIGHT...WITH A PLUME OF FRESH SWELL TO 
8 FT PROPAGATING AS FAR WEST AS 92W DOWNSTREAM DURING THE DAY. 
THESE CONDITIONS WILL START TO ABATE BY 48 HOURS. FRESH GAP 
WINDS WILL CONTINUE THROUGH THE GULF OF PANAMA AS WELL OVER THE 
NEXT 24 TO 48 HOURS. SCATTERED SHOWERS AND THUNDERSTORMS WILL 
CONTINUE ALONG THE ITCZ BETWEEN 90W AND 100W...ENHANCED BY GAP 
WIND CONVERGENCE TO SOME EXTENT. STRONG CONVECTION ALONG THE 
ITCZ NEAR 105W/106W IS ENHANCED TO SOME EXTENT BY A TROPICAL 
WAVE MOVING THROUGH THE AREA. LITTLE CHANGE IS EXPECTED OVER THE 
NEXT 48 HOURS.

ELSEWHERE...EXCEPT AS NOTED ABOVE WITH DEVELOPING LOW PRES 
AREAS...THE MAIN WEATHER INFLUENCE WILL BE A WEAK SUBTROPICAL 
RIDGE N OF 20N...SUPPORTING WEAK MODEST TRADE WINDS OUTSIDE OF 
AREAS NEAR THE DEVELOPING LOW PRES AREAS. 
$$
CHRISTENSEN


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Page last modified: Friday, 03-Jul-2015 22:02:06 UTC