000 AXPZ20 KNHC 151004 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT JUN 15 2013 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. ...TROPICAL WAVES... A TROPICAL WAVE OVER THE EASTERN PORTION OF THE AREA IS ANALYZED ALONG 96W FROM 11N TO 17N MOVING W ABOUT 15 KT. THE WAVE IS UNDERNEATH THE EASTERN PERIPHERY OF AN UPPER LEVEL RIDGE. DEEP CONVECTION ASSOCIATED WITH THE WAVE HAS JUST ABOUT TOTALLY DISSIPATED...EVEN THOUGH THE 700MB-850MB STREAMLINE PATTERN INDICATE LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE WAVE. SATELLITE WATER VAPOR SHOWS POCKETS OF DRY AIR ADVECTING FROM E TO W OVER THE WAVE HAMPERING ANY ASSOCIATED DEEP CONVECTION FROM DEVELOPING FOR THE THE TIME BEING. JUST TO THE S OF THE WAVE THE TOTAL PRECIPITABLE WATER (TPW) PRODUCT REVEALS DEEP LAYER ATMOSPHERIC MOISTURE ALONG AND ADJACENT TO THE MONSOON TROUGH. THIS IS WHERE DEEP CONVECTION IS OCCURRING AS DESCRIBED BELOW. THE WAVE IS FORECAST TO WEAKEN AS IT REACHES NEAR 100W TONIGHT ...THEN BECOME LESS DISCERNIBLE AT THE SURFACE BY SUN NIGHT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 10N100W TO 08N115W TO LOW PRES NEAR 09N126W 1010 MB. ITCZ AXIS EXTENDS FROM THE LOW PRES NEAR 09N126W TO 08N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120 NM S OF AXIS BETWEEN 90W-100W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF THE AXIS BETWEEN 103W-109W...AND ALSO WITHIN 60 NM S OF AXIS BETWEEN 80W-86W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF AXIS BETWEEN 110W-118W. ...DISCUSSION... ALOFT...BROAD UPPER TROUGH COVERS THE AREA N OF ABOUT 24N WITH ASSOCIATED W TO SW FLOW EVIDENT THROUGHOUT THIS PORTION OF THE AREA. THESE WINDS ARE IN CONFLUENCE ACROSS THIS AREA WITH AMPLE MODERATE TO STRONG SUBSIDENCE LEADING TO DRY AND STABLE. OVER THE FAR SE PORTION OF THE AREA...AN ANTICYCLONE DRIFTING W IS LOCATED OVER WEST/CENTRAL MEXICO NEAR 19N103W WITH AN ASSOCIATED RIDGE EXTENDING SE ALONG THE COAST OF MEXICO TO NEAR 12N92W. THIS IS THE SAME ANTICYCLONE FEATURE MENTIONED ABOVE UNDER TROPICAL WAVES. ANOTHER RIDGE EXTENDS FROM THE SAME ANTICYCLONE TO THE N TOWARDS TEXAS. JUST TO THE E OF THE AREA...AN UPPER LEVEL TROUGH ACROSS THE NW CARIBBEAN STRETCHES FROM CENTRAL CUBA SW TO A BASE NEAR THE PACIFIC COASTS OF EL SALVADOR AND HONDURAS. DIFFLUENT FLOW BETWEEN THIS TROUGH AND THE RIDGE IS AIDING IN THE DEVELOPING OF NEW TSTM CELLS BETWEEN EL SALVADOR AND THE MONSOON TROUGH. AN E TO W RIDGE SE OF THE CARIBBEAN UPPER TROUGH IS SUPPORTING CLUSTERS OF SCATTERED STRONG CONVECTION OVER THE GULF OF PANAMA...AND OVER THE COSTA RICA/ PANAMA BORDER. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 6.5N82W. THE 0618 UTC ASCAT PASS CAPTURED S SMALL CYCLONIC SWIRL THAT MARKS A WEAK 1010 MB LOW THAT IS EMBEDDED ALONG THE MONSOON TROUGH NEAR 09N126W. ISOLATED TSTMS ARE WITHIN 60 NM NE OF THE LOW. THIS LOW IS EXPECTED TO GRADUALLY DISSIPATE OVER THE NEXT 24-36 HOURS AS IT DRIFTS WESTWARD. TO THE W OF THE LOW...A PERSISTENT SURFACE TROUGH IS ANALYZED N OF THE ITCZ ALONG A POSITION FROM ABOUT 13N133W TO 8.5N137W. THE 0618 UTC ASCAT PASS CAUGHT JUST THE WESTERN FRINGE OF THIS TROUGH...BUT SUGGESTED THAT A SMALL POCKET OF NE 20 KT EXISTS WITHIN 90 NM TO ITS W. THE TROUGH COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE AS OBSERVED IN THE TOTAL PRECIPITABLE WATER PRODUCT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF LINE FROM 12N132W TO 12N137W. THE TROUGH IS FORECAST BY THE MODELS TO CONTINUE ON A WESTWARD MOTION OVER THE NEXT 48 HOURS...AFTER WHICH TIME IT WILL BE FORECAST TO BE NEAR 139W. A TIGHT PRES GRADIENT WILL REMAIN TO ITS W ALLOWING FOR LITTLE CHANGE TO THE NE 20 KT WINDS SHOWN BY THE 0618 UTC ASCAT. SEAS UNDER THE 20 KT WINDS ARE EXPECTED TO BE 8-9 FT. THE TIGHT PRES GRADIENT W OF THE ABOVE TROUGH IS DUE TO ITS INTERACTION WITH HIGH PRES RIDGING ASSOCIATED WITH A 1030 MB HIGH NW OF THE AREA AT 40N14W...AND EXTENDS INTO THE DISCUSSION AREA THROUGH 32N133W...AND REACHES TO NEAR 21N115W. A TIGHT PRES GRADIENT BETWEEN THIS SAME RIDGE AND GENERALLY LOWER PRES OVER THE U.S. W COAST IS SUPPORTING FRESH TO STRONG WINDS ALONG THE NORTH-CENTRAL COAST OF CALIFORNIA. NW TO N SWELLS OF 8 TO 9 FT RELATED TO THESE WINDS AND CONFIRMED BY ALTIMETER DATA FROM FRI PASS CONTINUE TO PROPAGATE S AND SE ACROSS THE NORTH WATERS MAINLY N OF 26N BETWEEN 119W AND 129W. SEAS ARE EXPECTED TO SUBSIDE TO LESS THAN 8 FT TONIGHT AS THE PRES GRADIENT JUST NE OF THE AREA RELAXES AS THE ATTENDANT HIGH PRES CENTER SHIFTS S AND WEAKENS IN RESPONSE TO A WEAKENING COLD FRONT THAT PASSES JUST TO THE N OF THE DISCUSSION AREA. LONG PERIOD CROSS EQUATORIAL SW SWELLS...WITH LEADING EDGE PERIOD OF 18-19 SECONDS HAVE REACHED MOST OF THE COASTLINE OF CENTRAL AMERICA AND MEXICO BRINGING ROUGH SURF CONDITIONS TO THOSE COASTS. WAVEWATCH GUIDANCE PROJECTS THESE CONDITIONS TO SUBSIDE ON SUN. $$ AGUIRRE