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Eastern Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 042201
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC SAT JUL 04 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...                                        
1007 MB LOW PRESSURE IS CENTERED NEAR 06N123W MOVING W-NW AT 5 
TO 10 KT. THE LOW FORMED ALONG A WELL DEFINED TROPICAL WAVE IN A 
LARGE AREA OF PERSISTENT CONVECTION INDUCED BY A KELVIN WAVE 
OVER THE PAST SEVERAL DAYS. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION IS CURRENTLY ACTIVE E OF THE CENTER FROM 10N 
TO 11N BETWEEN 118W AND 125W. AN 11 UTC RAPIDSCAT PASS INDICATED 
A LARGE SWATH OF FRESH TO STRONG SE WINDS OVER THIS AREA. 
CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR TROPICAL 
CYCLONE DEVELOPMENT OVER THE NEXT FEW DAYS. 

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS N OF 10N ALONG 103W/104W DRIFTING W. THIS 
IS ON THE SOUTHERN EDGE OF AN UPPER LOW CENTERED NEAR 
14N105W...WHICH IS ENHANCING SCATTERED MODERATE CONVECTION FROM 
13N TO 14N 100W AND 110W.

TROPICAL WAVE EXTENDS FROM 10N TO 15N ALONG 115W/116W MOVING W 
10 TO 15 KT. THIS FEATURES SHOWS UP IN THE LOWER TO MID LEVELS 
OF THE ATMOSPHERE. DESPITE STRONG AND DRY NW SHEAR...SPEED 
CONVERGENCE OF FRESH TO STRONG SE FLOW NOTED IN AN 11 UTC 
RAPIDSCAT PASS IS SUPPORTING AN AREA OF CONVECTION NEAR 
12.5N116W. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH AXIS EXTENDS FROM LOW PRES NEAR 05N78W 1006 
MB TO 09N85W TO 05N95W TO 09N100W. A SERIES OF TROPICAL WAVES 
INTERACTING WITH FAVORABLE CONDITIONS ALOFT HAS BROKEN DOWN THE 
ITCZ W OF 105W...AND THE ITCZ IS NOT CLEARLY EVIDENT AT THIS 
TIME. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 150 NM S OF AXIS E OF 87W...AND WITHIN 180 NM N AND 150 
NM S OF AXIS BETWEEN 90W AND 100W. 

...DISCUSSION...                                             

N OF 15N E OF 120W...A FEW THUNDERSTORMS WERE ACTIVE OVER THE 
CENTRAL GULF OF CALIFORNIA THIS MORNING NEAR ISLA TORTUGA. THE 
GERMAN RESEARCH VESSEL SONNE WAS NEARBY REPORTED WINDS TO 25 KT 
NEAR THE CONVECTION. OTHERWISE CONDITIONS REMAIN FAIRLY DRY OVER 
THE MID TO UPPER LEVELS OF THE ATMOSPHERE TO SUPPORT WIDESPREAD 
CONVECTION. LIGHT TO MODERATE WINDS PERSIST ON THE WESTERN EDGE 
OF THE SUBTROPICAL RIDGE. RECENT ALTIMETER DATA INDICATES SEAS 
OF 4 TO 5 FT OFF THE BAJA PENINSULA AND OPEN WATERS ELSEWHERE N 
OF 15N E OF 120W. A 16 UTC ASCAT PASS INDICATED FRESH GAP WIND 
FLOW THROUGH THE GULF OF TEHUANTEPEC...BETWEEN RELATIVELY LOW 
PRES S OF THE AREA AND RIDGING OVER THE GULF OF MEXICO TO THE 
NORTH. FOR THE NEXT COUPLE OF DAYS...THE SUBTROPICAL RIDGE WILL 
INCREASE SLIGHTLY ALLOWING A SLIGHT INCREASE IN NW FLOW OFF THE 
COAST OF THE BAJA PENINSULA. OTHERWISE NO MAJOR CHANGES ARE 
ANTICIPATED.

S OF 15N E OF 110W...THE CARIBBEAN JET EXTENDING INTO THE FAR 
EASTERN NORTH PACIFIC CONTINUES TO PRODUCE PULSING STRONG GAP 
WIND FLOW ACROSS THE GULF OF PAPAGAYO. THE MAIN PULSES ARE 
OCCURRING DURING THE OVERNIGHT HOURS...WITH A PLUME OF SHORTER 
PERIOD SWELL OF 8 FT PROPAGATING AS FAR WEST AS 95W DOWNSTREAM 
DURING THE DAY. ELSEWHERE...FRESH GAP WINDS WILL CONTINUE 
THROUGH THE GULF OF PANAMA DURING THE NEXT 24 TO 36 HOURS. 
OUTSIDE OF THESE PLUMES...SEAS CONTINUE TO BE 4 TO 5 FT WITH 
LIGHT TO MODERATE FLOW.

ELSEWHERE...HIGH PRESSURE OF 1018 MB CENTERED NEAR 27N132W 
EXTENDS A RIDGE AXIS SE TO S OF THE BAJA PENINSULA. GENERALLY 
MODERATE TRADES ARE NOTED SOUTH OF THE RIDGE. A 1007 MB LOW IS 
CENTERED NEAR 13N139W. AND EARLY SCATTEROMETER PASS INDICATED 
FRESH TO STRONG WINDS ON THE SE QUADRANT OF THIS LOW. THE 
OVERALL TREND IS WEAKENING AND NO SIGNIFICANT CONVECTION IS NOTED 
AS CONDITIONS BECOME LESS FAVORABLE FOR TROPICAL CYCLOGENESIS. 
THE LOW WILL DRIFT W OF THE AREA THROUGH TONIGHT. A KELVIN WAVE 
MOVING THROUGH THE AREA CONTINUES TO AID LOW LEVEL CONVERGENCE 
AND ACTIVE WEATHER FROM 03N TO 13N BETWEEN 90W AND 125W. THE 
ACTIVE CONVECTION ASSOCIATED WITH THE KELVIN WAVE HELPED WITH 
THE GENERATION OF BOTH LOW PRESSURE SYSTEMS DESCRIBED ABOVE. THE 
CONTINUED CONVECTION HAS ALSO HELPED TO GENERATE AN UNSTABLE 
BACKGROUND ENVIRONMENT WHICH HAS LED TO A BREAKDOWN OF THE ITCZ. 

$$
CHRISTENSEN


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Page last modified: Saturday, 04-Jul-2015 22:01:24 UTC