000 AXPZ20 KNHC 210225 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED MAY 21 2014 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0215 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A MONSOON TROUGH EXTENDS W FROM THE NW COAST OF COLOMBIA AT 08.5N77W TO THE PACIFIC COAST OF COSTA RICA AT 09N84W...THEN TURNS SW TO 07N90W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ CONTINUES SW TO 07N95W...THEN TURNS NW TO A 1011 MB LOW PRESSURE AT 10N105W...THEN IS ILL- DEFINED TO ANOTHER 1011 MB LOW PRESSURE AT 13N117W. THE ITCZ CONTINUES SW TO BEYOND 04N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...ACCOMPANIED BY FREQUENT LIGHTNING...IS OVER AND TO THE S OF THE EASTERN SEGMENT OF THE MONSOON TROUGH FROM 02-09N E OF 88W. SIMILAR CONVECTION IS NOTED OVER THE NE QUADRANT OF THE LOW PRESSURE AT 10N105W ROUGHLY WITHIN 120 NM OF LINE FROM 13N103W TO 08N103W...AND S OF THE LOW PRESSURE AT 13N117W WITHIN 90 NM EITHER SIDE OF A LINE FROM 14N111W TO 07N121W...AND ALONG THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM 05N125W TO 08N127W TO 08N132W. THE LOW PRESSURE AT 10N105W IS EXPECTED TO DRIFT W-NW THROUGH THE WEEKEND WITH GUIDANCE SUGGESTING DEEPENING OF THE LOW NEAR 12N112W EARLY NEXT WEEK. THE LOW PRESSURE NEAR 12N116W IS EXPECTED TO REMAIN QUASI-STATIONARY AND GRADUALLY LOSE IDENTITY IN THE MONSOON TROUGH AS IT CONTINUES E INTO THE LOW PRESSURE CURRENTLY NEAR 10N105W. ISOLATED MODERATE CONVECTION IS OBSERVED WELL N OF THE MONSOON TROUGH FROM 10-16N BETWEEN 87-100W. ...DISCUSSION... AN UPPER ANTICYCLONE HAS FORMED OVER THE FAR NW PORTION AT 31N140W. AN UPPER ANTICYCLONE IS OVER THE EPAC AT 12N96W WITH A RIDGE EXTENDING N THROUGH ANOTHER ANTICYCLONE OVER SE TEXAS WITH THE RIDGE CONTINUING N ACROSS THE CENTRAL CONUS. AN UPPER TROUGH CONTINUES BETWEEN THESE RIDGES FROM 32N120W TO A BASE AT OVER THE TROPICAL PACIFIC AT 12N118W. A NARROW BAND OF UPPER MOISTURE IS NOTED JUST E OF THE UPPER TROUGH WITHIN 60 NM EITHER SIDE OF A LINE FROM 28N120W TO ACROSS CENTRAL ARIZONA. OTHERWISE...THE UPPER LEVELS APPEAR VERY DRY N OF 13N W OF 115W. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS NEAR 07N126W WITH A RIDGE EXTENDING W TO 10N140W...AND ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 120-138W. CONVECTION IS ALSO ENHANCED BETWEEN 110-120W. ISOLATED CONVECTION IS OBSERVED ELSEWHERE UNDER THE TROPICAL RIDGE BETWEEN 90-110W. DEBRIS MOISTURE IS STREAMING NE AND E ACROSS CENTRAL AMERICA FROM 12-21N. AN UPPER ANTICYCLONE IS ESTIMATED NEAR 06N80W AND IS ENHANCING THE CONVECTION ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE FANS OUT IN ALL DIRECTIONS COVERING THE UPPER LEVELS FROM 02S-11N BETWEEN 73-89W. A SURFACE RIDGE EXTENDS FROM 32N134W TO 19N111W. ANTICYCLONIC SURFACE WINDS ARE GENERALLY AT 15-20 KT AROUND THE PERIPHERY OF THIS RIDGE...EXCEPT NORTHWESTERLY 20-25 KT WINDS ARE EXPECTED TO THE N OF 28N E OF 116W TO THE BAJA PENINSULA FOR THE NEXT 12 HOURS OR SO. GULF OF TEHUANTEPEC...THE NOCTURNAL NORTHERLY DRAINAGE FLOW WILL MAX AT 20 KT TONIGHT AND EACH NIGHT THROUGH THU NIGHT...THEN WEAKEN TO A 15 KT MAX ON FRI NIGHT. $$ NELSON