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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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