000 AXPZ20 KNHC 290951 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON JUL 29 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 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS E TO W FROM THE NW COAST OF COLOMBIA AT 08N77W TO ACROSS SOUTHERN PANAMA TO 08N84W...THEN TURNS WNW TO AN EMBEDDED SURFACE LOW PRESSURE AT 10N101W...THEN W TO 10N122W...THEN SW TO 08N132W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN INTERTROPICAL CONVERGENCE ZONE WHICH CONTINUES W TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG STRONG CONVECTION IS OBSERVED ALONG THE COAST OF COLOMBIA FROM 04-09N E OF 79W...WITHIN 90 NM OF THE COAST OF CENTRAL AMERICA FROM 81-87W...FROM 07-13N BETWEEN 89-93W...FROM 07-13N BETWEEN 106-125W...AND WITHIN 90 NM EITHER SIDE OF A LINE FROM 14N128W TO 11N134W. ...DISCUSSION... AN UPPER TROUGH EXTENDS SW FROM CENTRAL CALIFORNIA INTO THE DISCUSSION AREA FROM 32N121W THROUGH AN UPPER CYCLONE AT 18N124W...WITH THE TROUGH CONTINUING S LOSING IDENTITY OVER THE DEEP TROPICS NEAR 07N125W. AN ASSOCIATED SURFACE TROUGH WILL DIP INTO THE AREA FROM 32N120W TO 27N123W TONIGHT...AND MOVE E ACROSS THE ADJACENT WATERS OF THE NORTHERN BAJA CALIFORNIA PENINSULA ON TUE. THE UPPER TROUGH IS BEING REINFORCED BY A SECONDARY UPPER TROUGH FROM 32N123W TO 22N130W AND IS ACCOMPANIED BY 360 NM WIDE OF VERY DRY AIR ALOFT. THE MEAN AXIS OF THESE UPPER TROUGHS EFFECTIVELY DIVIDES THE UPPER LEVELS OF THE DISCUSSION AREA TO THE E AND W OF 123W. TO THE W OF 123W IS AN UPPER ANTICYCLONE CENTERED AT 19N139W WITH ITS ENVELOPE COVERING THE DISCUSSION AREA FROM 10-26N W OF 130W. ANOTHER UPPER TROUGH IS ROTATING E OVER THE NW PORTION FROM 32N133W TO 28N140W. A THIN LINE OF UPPER DEBRIS MOISTURE FROM FLOSSIE IS ADVECTED NE JUST AHEAD OF THIS TROUGH...AND SOME UPPER MOISTURE ALSO CONTINUES UNDER THE RIDGE FROM 17-23N BETWEEN 128W-143W. WEAK UPPER DIFFLUENCE S OF THE RIDGE IS SUPPORTING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE WESTERN PORTION OF THE MONSOON TROUGH AND ITCZ...WITH THE DEBRIS MOISTURE ADVECTED SW TO ALONG 04N. A LARGE UPPER ANTICYCLONE IS QUASI STATIONARY OVER THE NORTHERN OLD MEXICO WITH ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING S OVER THE DISCUSSION AREA TO THE N OF 19N BETWEEN 102-118W. DENSE DEBRIS MOISTURE...FROM PREVIOUS CONVECTION MOSTLY ALONG THE SIERRA MADRE OCCIDENTAL...IS ADVECTED W OFF THE PACIFIC COAST OF MEXICO AND ACROSS THE SOUTHERN GULF OF CALIFORNIA AND THE BAJA PENINSULA. SOME OF THIS UPPER MOISTURE WILL SPREAD N AND NE ACROSS NEW MEXICO AND W TEXAS TODAY. A SMALL UPPER CYCLONE HAS BEEN SHIFTING W ALONG THE PACIFIC COAST OF MEXICO AND IS NOW CENTERED AT 17N100W. ITS CYCLONIC CIRCULATION CONTINUES TO TAP MONSOON TROUGH DEBRIS MOISTURE AND ADVECTS IT N ACROSS THE PACIFIC TO THE N OF 11N BETWEEN 95-101W FEEDING INTO SMALL CLUSTERS OF CONVECTION OVER INTERIOR MEXICO TO THE E OF THE UPPER CENTER AND LIKELY TO INCREASE LATER TODAY DURING PEAK HEATING. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS NEAR 10N95W WITH A RIDGE EXTENDING E TO 10N78W. THE ASSOCIATED UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE E PORTION OF THE MONSOON TROUGH AND ITS EMBEDDED SURFACE LOW. AREAS OF INTENSE CONVECTION... ACCOMPANIED BY FREQUENT LIGHTNING...IS REPEATING AGAIN THIS MORNING ALONG WESTERN COLOMBIA FROM 03N-10N...AND OVER THE SW CARIBBEAN WITH THE STRONG CLUSTERS MOVING OVER NORTHERN COSTA RICA AND E NICARAGUA. GUIDANCE CONTINUES TO SUGGEST A SERIES OF CYCLONIC SWIRLS WILL FORM ALONG THE MONSOON TROUGH OVER THE NEXT FEW DAYS WITH THE GFS THE MOST AGGRESSIVE. CURRENTLY AN EMBEDDED SURFACE LOW IS NEAR 10N101W. USING A BLEND OF GUIDANCE THIS LOW IS FORECAST TO MOVE WESTWARD ALONG THE MONSOON TROUGH ACCOMPANIED BY AN EXPANDING AREA OF 20-25 KT WINDS MAINLY OVER ITS EASTERN SEMICIRCLE. CROSS EQUATORIAL SOUTHERLY SWELL WILL CONTINUE THROUGH TONIGHT ACROSS THE TROPICAL WATERS E OF 115W MIXING WITH THE WAVES FORMING OVER THE E SEMICIRCLE OF THE SURFACE LOW. $$ NELSON