000 AXPZ20 KNHC 162159 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT JUL 16 2011 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 2030 UTC. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 08N78W TO LOW PRES AT 10N85W TO LOW PRES AT 17N104W TO 13N112W TO 08N135W. ITCZ AXIS LIES FROM 13N112W TO BEYOND 07N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND FROM 10N TO 18N BETWEEN 93W AND 106W. SCATTERED MODERATE CONVECTION LIES FROM 04N TO 10N BETWEEN 81W AND 92W AND N OF 10N E OF 89W. ...DISCUSSION... A LONG WAVE TROUGH LIES ALONG THE WESTERN U.S. COAST AND EXTENDS INTO THE FORECAST AREA FROM 32N126W TO 19N133W. THIS TROUGH WILL BE RELOADED WITH NORTHERN STREAM ENERGY SUN AND SHIFT WESTWARD THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. THIS PERSISTENT TROUGHING IS BLOCKING ANY MIGRATION OF THE DEEP LAYER HIGH PRES ASSOCIATED WITH THE SUBTROPICAL HIGH WHICH IS EXPECTED TO REMAIN ANCHORED N OF HAWAII ALONG 40N...WELL NW OF ITS CLIMATOLOGICAL POSITION. TRADE WINDS HAVE DIMINISHED TO LESS THAN 20 KT UNDER THE RELATIVELY WEAK PRES GRADIENT BETWEEN THIS ITCZ AND THE DISPLACED SUBTROPICAL HIGH. THESE CONDITIONS WILL CONTINUE FOR THE NEXT FEW DAYS. MEANWHILE...THE 1648 UTC ASCAT PASS SHOWS WIDESPREAD FRESH N TO NW WINDS OFF THE W COAST OF THE BAJA PENINSULA AND AS FAR S AS 19N. THESE WINDS ARE EXPECTED TO DIMINISH THROUGH MON MORNING AS THE REFLECTION OF THE ENERGY REINFORCING THE UPPER TROUGHING OFF THE U.S. WEST COAST DISRUPTS THE STRONG PRES GRADIENT OVER NE WATERS. THE AFOREMENTIONED BLOCKING PATTERN ALOFT ALSO EXTENDS INTO THE CENTRAL U.S. WHERE A STRONG ANTICYCLONE OVER NEBRASKA IS EXPECTED TO REMAIN THE NEXT FEW DAYS. AN UPPER RIDGE EXTENDS SW FROM THE ANTICYCLONE THROUGH NW MEXICO AND THE CENTRAL GULF OF CALIFORNIA TO 26N112 THROUGH 19N120W TO 19N128W. THIS RIDGE WILL BE NUDGED SLOWLY NORTHWESTWARD AS THE TROUGHING TO IS E SHIFTS WESTWARD. A WEAK UPPER TROUGH PARALLELS THIS RIDGE TO ITS SE AND EXTENDS THROUGH CABO CORRIENTES...MEXICO TO 18N108W. A SECOND RIDGE THEN PARALLELS SE THIS TROUGH FROM A WEAK ANTICYCLONE OVER THE YUCATAN PENINSULA TO 12N100W. DIFFLUENCE OFF THE COAST OF SOUTHERN MEXICO BETWEEN THIS SOUTHERN RIDGE AXIS ALOFT AND THE UPPER TROUGH IS ENHANCING CONVECTION ALONG THE MONSOON TROUGH...INCLUDING NEAR A LOW PRES SYSTEM AT 17N104W. THIS CONVECTION IS DESCRIBED IN THE SECTION ABOVE. FRESH TO STRONG SW WINDS S OF THIS AREA OF ENHANCED CONVECTION ARE FEEDING LOW LEVEL SUBTROPICAL MOISTURE TOWARD THE MONSOON TROUGH. SOME DEVELOPMENT OF THIS LOW PRES SYSTEM IS POSSIBLE OVER THE NEXT TWO DAYS. A WELL ORGANIZED MID LEVEL LOW IS MAKING ITS WAY THROUGH COSTA RICA AND INTO THE PACIFIC AT THE MOMENT. IT IS REFLECTING A 1008 MB LOW AT THE SURFACE NEAR 10N85W. UPPER LEVEL DIFFLUENCE LIES OVER THIS LOW BETWEEN 30 TO 50 KT NE WINDS ALOFT S OF 09N AND LIGHTER NE WINDS ALOFT ACROSS SOUTHERN CENTRAL AMERICA. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING THE LARGE AREA OF DENSE CLOUDINESS AND CONVECTION OVER THE PACIFIC WATERS DESCRIBED IN THE SECTION ABOVE. THE UPPER LEVEL NORTHEASTERLY FLOW IS ADVECTING THE DEBRIS MOISTURE S TOWARD THE EQUATOR TO THE E OF 110W. WIDESPREAD RAINFALL...WITH LOCALIZED TRAINING DEEP CONVECTION...IS EXPECTED TO PERSIST ACROSS CENTRAL AMERICA DURING THE NEXT FEW DAYS. THIS MAY RESULT IN FLASH FLOODS AND MUDSLIDES THROUGH THE WEEKEND. THE SURFACE LOW IS EXPECTED TO TRACK WESTWARD ALONG 10N OVER THE NEXT TWO DAYS AND HAS THE POTENTIAL TO DEEPEN. $$ SCHAUER 000 AXPZ20 KNHC 162159 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT JUL 16 2011 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 2030 UTC. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 08N78W TO LOW PRES AT 10N85W TO LOW PRES AT 17N104W TO 13N112W TO 08N135W. ITCZ AXIS LIES FROM 13N112W TO BEYOND 07N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION CAN BE FOUND FROM 10N TO 18N BETWEEN 93W AND 106W. SCATTERED MODERATE CONVECTION LIES FROM 04N TO 10N BETWEEN 81W AND 92W AND N OF 10N E OF 89W. ...DISCUSSION... A LONG WAVE TROUGH LIES ALONG THE WESTERN U.S. COAST AND EXTENDS INTO THE FORECAST AREA FROM 32N126W TO 19N133W. THIS TROUGH WILL BE RELOADED WITH NORTHERN STREAM ENERGY SUN AND SHIFT WESTWARD THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. THIS PERSISTENT TROUGHING IS BLOCKING ANY MIGRATION OF THE DEEP LAYER HIGH PRES ASSOCIATED WITH THE SUBTROPICAL HIGH WHICH IS EXPECTED TO REMAIN ANCHORED N OF HAWAII ALONG 40N...WELL NW OF ITS CLIMATOLOGICAL POSITION. TRADE WINDS HAVE DIMINISHED TO LESS THAN 20 KT UNDER THE RELATIVELY WEAK PRES GRADIENT BETWEEN THIS ITCZ AND THE DISPLACED SUBTROPICAL HIGH. THESE CONDITIONS WILL CONTINUE FOR THE NEXT FEW DAYS. MEANWHILE...THE 1648 UTC ASCAT PASS SHOWS WIDESPREAD FRESH N TO NW WINDS OFF THE W COAST OF THE BAJA PENINSULA AND AS FAR S AS 19N. THESE WINDS ARE EXPECTED TO DIMINISH THROUGH MON MORNING AS THE REFLECTION OF THE ENERGY REINFORCING THE UPPER TROUGHING OFF THE U.S. WEST COAST DISRUPTS THE STRONG PRES GRADIENT OVER NE WATERS. THE AFOREMENTIONED BLOCKING PATTERN ALOFT ALSO EXTENDS INTO THE CENTRAL U.S. WHERE A STRONG ANTICYCLONE OVER NEBRASKA IS EXPECTED TO REMAIN THE NEXT FEW DAYS. AN UPPER RIDGE EXTENDS SW FROM THE ANTICYCLONE THROUGH NW MEXICO AND THE CENTRAL GULF OF CALIFORNIA TO 26N112 THROUGH 19N120W TO 19N128W. THIS RIDGE WILL BE NUDGED SLOWLY NORTHWESTWARD AS THE TROUGHING TO IS E SHIFTS WESTWARD. A WEAK UPPER TROUGH PARALLELS THIS RIDGE TO ITS SE AND EXTENDS THROUGH CABO CORRIENTES...MEXICO TO 18N108W. A SECOND RIDGE THEN PARALLELS SE THIS TROUGH FROM A WEAK ANTICYCLONE OVER THE YUCATAN PENINSULA TO 12N100W. DIFFLUENCE OFF THE COAST OF SOUTHERN MEXICO BETWEEN THIS SOUTHERN RIDGE AXIS ALOFT AND THE UPPER TROUGH IS ENHANCING CONVECTION ALONG THE MONSOON TROUGH...INCLUDING NEAR A LOW PRES SYSTEM AT 17N104W. THIS CONVECTION IS DESCRIBED IN THE SECTION ABOVE. FRESH TO STRONG SW WINDS S OF THIS AREA OF ENHANCED CONVECTION ARE FEEDING LOW LEVEL SUBTROPICAL MOISTURE TOWARD THE MONSOON TROUGH. SOME DEVELOPMENT OF THIS LOW PRES SYSTEM IS POSSIBLE OVER THE NEXT TWO DAYS. A WELL ORGANIZED MID LEVEL LOW IS MAKING ITS WAY THROUGH COSTA RICA AND INTO THE PACIFIC AT THE MOMENT. IT IS REFLECTING A 1008 MB LOW AT THE SURFACE NEAR 10N85W. UPPER LEVEL DIFFLUENCE LIES OVER THIS LOW BETWEEN 30 TO 50 KT NE WINDS ALOFT S OF 09N AND LIGHTER NE WINDS ALOFT ACROSS SOUTHERN CENTRAL AMERICA. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING THE LARGE AREA OF DENSE CLOUDINESS AND CONVECTION OVER THE PACIFIC WATERS DESCRIBED IN THE SECTION ABOVE. THE UPPER LEVEL NORTHEASTERLY FLOW IS ADVECTING THE DEBRIS MOISTURE S TOWARD THE EQUATOR TO THE E OF 110W. WIDESPREAD RAINFALL...WITH LOCALIZED TRAINING DEEP CONVECTION...IS EXPECTED TO PERSIST ACROSS CENTRAL AMERICA DURING THE NEXT FEW DAYS. THIS MAY RESULT IN FLASH FLOODS AND MUDSLIDES THROUGH THE WEEKEND. THE SURFACE LOW IS EXPECTED TO TRACK WESTWARD ALONG 10N OVER THE NEXT TWO DAYS AND HAS THE POTENTIAL TO DEEPEN. $$ SCHAUER