000 AXPZ20 KNHC 061001 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT OCT 06 2012 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 0930 UTC. ...SPECIAL FEATURE... EMBEDDED SURFACE LOW PRESSURE CONTINUES WITHIN THE MONSOON TROUGH NEAR THE POSITION OF 13N118W AND IS ESTIMATED AT 1008 MB...MOVING W OR 280 DEG AT 11 KT. THE LOW IS MOVING W UNDER A LARGE RIDGE WITH FAVORABLE UPPER LEVEL DIFFLUENCE AND LIGHT WINDS ALOFT EXPECTED FOR A COUPLE OF DAYS. WATER VAPOR IMAGERY DEPICTS IMPRESSIVE UPPER LEVEL OUTFLOW OVER ITS NORTHERN SEMICIRCLE. THE LATEST SATELLITE IR ENHANCEMENT IMAGERY SHOWS THE EARLIER OBSERVED MINIMAL CONVECTION NEAR THE CENTER NOW QUICKLY FLARING UP WITH VERY COLD CLOUD TOPS. THIS CONVECTION IS DEPICTED OF NUMEROUS TYPE INTENSITY WITHIN 180 NM OF THE CENTER IN THE N AND NE QUADRANTS...30 NM OF THE CENTER IN THE SE QUADRANT...75 NM IN THE SW QUADRANT AND 120 NM IN THE NW QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOTED FROM 15N TO 17N BETWEEN 113W AND 117W. OTHER CONVECTION DEVELOPING IN CLUSTERS TO THE SW OF THE LOW ARE NOTED AS SCATTERED MODERATE/ISOLATED STRONG CONVECTION IN CLUSTERS ARE FORMING A BAND TO THE SW OF THE LOW WITHIN 30 NM OF LINE FROM 13N120.5W TO 13N122W TO 14N123W. AN ASCAT PASS FROM NEAR 0500 UTC LAST NIGHT REVEALED NE WINDS OF ABOUT 20-25 KT TO ITS N AND NE FROM 13N TO 18N BETWEEN 115W AND 122W. IT ALSO REVEALED S TO SW WINDS TO ITS SE AND S FROM 7N TO NEAR 10N AND BETWEEN 115W AND 120W. THE LOW IS FORECAST TO TRACK WNW THROUGH THE NEXT 24-30 HRS THEN SLOW DOWN AND TRACK MORE TO THE NW OR N INTO 48 HRS. THE LOW WILL HAVE THE POTENTIAL TO INTENSIFY INTO A TROPICAL DEPRESSION DURING THIS PERIOD. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHERN CARIBBEAN ALONG 11N FROM THE COLOMBIAN COAST TO NORTHERN COSTA RICA TO 10N85W ...THEN DIPS SW TO 09N94W THEN TURNING NW TO 14N112W...THEN SW AGAIN THROUGH THE LOW AT 13N118W. THE TROUGH AXIS CONTINUES SW FROM THE LOW TO 09N125W...TO 11N131W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES SW TO BEYOND 07N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITH OCCASIONAL LIGHTNING IS SEEN WITHIN 180 NM S OF THE MONSOON TROUGH BETWEEN 85W-88W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE TROUGH BETWEEN 91W-94W...AND ALSO WITHIN 45 NM OF LINE 09N117W TO 09N121W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE IS IDENTIFIED TO BE NEAR 19N117W WITH UPPER RIDGES EXTENDING N BEYOND 32N118W...AND WSW TO A CREST AT 18N140W. AN UPPER 50-90 KT JET IS DETECTED BY CLOUD MOTION VECTORS ALONG THE NW AND N PERIPHERY OF THE ANTICYCLONE ADVECTING A 390 NM WIDE PLUME OF UPPER MOISTURE FROM THE CENTRAL PACIFIC NE AND E ACROSS THE NORTHERN RIDGE CREST TURNING SE AND SPILLING ACROSS SOUTHERN CALIFORNIA AND THE SW U.S. THIS JET SEPARATES THE ANTICYCLONE FROM A REX BLOCK PATTERN THAT HAS SET SET UP WELL TO THE N OF THE AREA. UPPER LEVEL DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THIS LARGE RIDGE IS HELPING TO SUPPORT THE CONVECTION ASSOCIATED WITH THE LOW NEAR 13N118W AS WELL AS CONVECTION NEAR THE MONSOON TROUGH AS DESCRIBED ABOVE. THE RESULTANT DEBRIS MOISTURE IS FANNING OUT N TO ALONG 21N BETWEEN 109W-121W...AND ALSO FANNING OUT SWD TO ALONG 05N BETWEEN 112W-122W BEFORE EVAPORATING IN THE DRY AIR ALOFT. OTHERWISE ...THE LARGE ANTICYCLONE IS SUPPRESSING CONVECTION ACROSS THE ENTIRE SUBTROPICAL PORTION OF THE DISCUSSION AREA AS OBSERVED BY THE VAST AMOUNT OF MODERATE TO STRONG SUBSIDENCE PRESENT THERE. BROKEN TO SCATTERED STRATOCUMULUS CLOUDS MOVING WESTWARD ARE PRESENT N OF 19N AND BETWEEN 121W-133W. THE LOW ASSOCIATED WITH THE REX BLOCK PATTERN IS FORECAST TO BEGIN TO MOVE SE TOWARDS THE FAR NE CORNER OF THE AREA EARLY NEXT WEEK. THE SURFACE TROUGH ASSOCIATED WITH THE LOW MAY BRUSH THE FAR NORTHERN FRINGE OF THE AREA E OF 135W DURING THAT TIME. AN UPPER SHORTWAVE TROUGH OVER THE CENTRAL CONUS EXTENDS SW ACROSS CENTRAL MEXICO AND CONTINUES S ACROSS THE DEEP TROPICS ROUGHLY ALONG 100W AS AN INVERTED TROUGH. THIS TROUGH SEPARATES THE UPPER FLOW OVER THE TROPICAL PACIFIC. BROAD UPPER RIDGING IS NOTED E OF THIS UPPER TROUGH AND ENHANCING THE CONVECTION ALONG THE EASTERN SEGMENT OF THE LOWER LEVEL MONSOON TROUGH AS PREVIOUSLY DESCRIBED. SOME OF THE RESULTANT DEBRIS MOISTURE IS ADVECTED NNE ACROSS CENTRAL AMERICA E OF 96W. SOME OF THIS MOISTURE IS ALSO BEING ADVECTED S TO NEAR 02N E OF 94W. ELSEWHERE AT THE LOW LEVELS...BROAD SURFACE RIDGING COVERS THE DISCUSSION AREA N OF 18N W OF 115W WITH AN ASSOCIATED 1020 MB HIGH CENTER AT 31N129W. SOUTHWESTERLY LOW LEVEL MONSOONAL WINDS AT 15-20 KT...ALONG WITH CROSS EQUATORIAL S SWELL...CONTINUES TO RESULT IN AN AREA OF SEAS 6-8 FT IN THE AREA BOUNDED FROM 08N TO 10N BETWEEN 114W-120W. THIS AREA WILL SHIFT N TO ALONG 13N ON SAT...THEN WINDS WILL DIMINISH TO 15 KT AND SEAS WILL SUBSIDE TO 4-7 FT ON SUN. IN THE MEANTIME...NW WINDS NE OF THE SURFACE RIDGE WILL INCREASE TO 20-25 KT OVER THE AREA N OF 28N E OF 118W TO THE NORTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA THIS AFTERNOON...WITH LITTLE CHANGE EXPECTED THROUGH EARLY TUE. THIS GRADIENT IS THEN FORECAST TO RELAX AFTER TUE. LONG PERIOD SOUTHERN HEMISPHERIC S TO SW SWELLS ARE FORECAST BY WAVE MODEL GUIDANCE TO SPREAD ACROSS THE ENTIRE AREA E OF 120W INTO EARLY NEXT WEEK. THESE SWELLS ARE EXPECTED TO CULMINATE IN 4-5 FT SEAS ALONG MUCH OF THE COAST OF MEXICO INCLUDING THE SOUTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA...AND THE SOUTHERN TIER OF THE GULF OF MEXICO. GAP WINDS...N TO NE WINDS OF 20-25 KT ARE EXPECTED TO PULSE ACROSS THE GULF OF TEHUANTEPEC THROUGH THIS MORNING...THEN DIMINISH BY MIDDAY TODAY. THESE WINDS ARE FORECAST BY MODEL GUIDANCE FROM THE GFS AND NAM TO PULSE AGAIN TO 20-25 KT STARTING LATE TONIGHT AND LAST INTO SUN AFTERNOON BEFORE DIMINISHING AGAIN. THE N-NE 20-25 KT WINDS RETURN AGAIN LATE SUN NIGHT AS HIGH PRES RIDGES SWD ACROSS CENTRAL AND SOUTHEASTERN MEXICO. $$ AGUIRRE