000 AXPZ20 KNHC 171006 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN JUL 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM N COLOMBIA WWD ACROSS PANAMA AND COSTA RICA TO LOW PRES AT 09.5N86W TO GULF OF TEHUANTEPEC NEAR 15.5N95W TO LOW PRES AT 18N105W. THE MONSOON TROUGH THEN BEGINS IN A ZONE OF BROAD CYCLONIC TURNING NEAR 16N107W TO 11N119W TO 11N132W TO 08N136W...WHERE IT TRANSITIONS TO THE ITCZ TO BEYOND 07N140W. SCATTERED TO NUMEROUS MODERATE TO STRONG WITHIN 180 NM N OF MONSOON TROUGH BETWEEN 86W AND 103W. SCATTERED MODERATE WITHIN 90 NM S OF MONSOON TROUGH BETWEEN 126W AND 131W. ...DISCUSSION... A LONG WAVE TROUGH LIES ALONG THE WESTERN U.S. COAST AND EXTENDS INTO THE FORECAST AREA FROM 32N126W TO 18N136W. THIS TROUGH WILL BE RELOADED WITH NORTHERN STREAM SHORTWAVE ENERGY DROPPING INTO THE BACK SIDE OF THE TROUGH TODAY...SHIFTING THE MEAN TROUGH WESTWARD THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. THIS PERSISTENT TROUGHING ALOFT OVER THE NE PACIFIC IS BLOCKING THE MIGRATION OF THE DEEP LAYER HIGH PRES ASSOCIATED WITH THE SUBTROPICAL HIGH. THE SURFACE HIGH IS EXPECTED TO REMAIN ANCHORED N OF HAWAII ALONG 40N...NW OF ITS CLIMATOLOGICAL POSITION. TRADE WINDS REMAIN LESS THAN 20 KT UNDER THE RELATIVELY WEAK PRES GRADIENT BETWEEN THE ITCZ AND THIS DISPLACED SUBTROPICAL HIGH. THESE CONDITIONS WILL CONTINUE FOR THE NEXT FEW DAYS. MEANWHILE...RECENT SCATTEROMETER PASSES SHOW WIDESPREAD FRESH N TO NW WINDS OFF THE W COAST OF THE BAJA PENINSULA AND AS FAR S AS 21N. THESE WINDS ARE EXPECTED TO DIMINISH TONIGHT THROUGH MON MORNING AS THE SURFACE REFLECTION OF THE NORTHERN STREAM ENERGY REINFORCING THE MEAN TROUGHING ALOFT OFF THE U.S. WEST COAST DISRUPTS THE STRONG PRES GRADIENT OVER NE WATERS. THE AFOREMENTIONED QUASISTATIONARY PATTERN ALOFT IS PART OF AN OMEGA BLOCK CENTERED OVER THE CENTRAL U.S. WHERE A STRONG ANTICYCLONE OVER NEBRASKA IS EXPECTED TO REMAIN THE NEXT FEW DAYS. AN UPPER RIDGE EXTENDS SW FROM THIS ANTICYCLONE THROUGH NW MEXICO AND THE CENTRAL GULF OF CALIFORNIA TO 26N113W TO 18N125W. THIS UPPER RIDGE WILL DRIFT SLOWLY NORTHWESTWARD AS THE TROUGHING TO IS E SHIFTS WESTWARD. A MIDDLE TO UPPER LEVEL CYCLONE WAS OVER N CENTRAL MEXICO MOVING W-NW...AND WAS HELPING TO CREATE DIVERGENT FLOW ALOFT IN ITS WAKE ACROSS THE FAR SW GULF OF MEXICO...WHERE DEEP CONVECTION WAS EXPANDING ACROSS FAR SW PORTIONS OF THE GULF OF CAMPECHE. UPPER LEVEL NE TO ELY FLOW CONTINUES ACROSS THE TROPICAL EPAC S OF 20N FROM CENTRAL AMERICA TO 125W...AND OVERLAY A BROAD ZONE OF FRESH TO STRONG MONSOONAL FLOW E OF 115W. THIS MONSOONAL CIRCULATION EXTENDS FROM A BROAD CYCLONIC FLOW CENTERED NEAR 18N107W E-SE IN A GRADUALLY NARROWING ZONE TO JUST OFFSHORE OF THE PACIFIC COAST OF COSTA RICA. SWLY WINDS CONTINUE TO PROVIDE ABUNDANT MOISTURE AND BROAD SCALE LOW LEVEL CONVERGENCE YIELDING ENHANCED CONVECTION FROM 08N TO 13N BETWEEN 94W AND 111W...WHILE SIMILAR CONDITIONS WERE YIELDING DEEP CONVECTION FROM 03N TO 09N BETWEEN 84W AND 89W. GLOBAL MODELS SHOW A TREND FOR THIS MONSOON TROUGH TO GRADUALLY BECOME MORE W TO E ALIGNED AS IT SINKS SLIGHTLY S DURING THE NEXT FEW DAYS...WITH THE POTENTIAL FOR ONE OR MORE LOW PRESSURE SYSTEMS TO DEVELOP AND INTENSIFY WITHIN THE TROUGH. A 1010 MB SURFACE LOW NEAR 09.5N86W HAS MOVED W ACROSS NRN COSTA RICA IN THE PAST 24 HOURS AND IS EXPECTED TO SHIFT W TO WNW DURING THE NEXT FEW DAYS...WITH DECREASING MOISTURE AND RAINFALL EXPECTED ACROSS HONDURAS AND NORTHERN GUATEMALA ON MONDAY. FRESH WINDS AND SEAS BUILDING 8 TO 10 FT SHOULD BE EXPECTED WITH THIS LOW THROUGH TUE...WITH THE POTENTIAL FOR FURTHER STRENGTHENING. A SECOND SURFACE LOW WAS DETECTED IN THE NW PORTION OF THE MONSOON TROUGH NEAR 18N105W...WITH A BROADER MORE DISTINCT CIRCULATION. THIS BROAD LOW WILL MOVE GRADUALLY W TO WSW OVER THE NEXT FEW DAYS AND SLOWLY WEAKEN OVER COOLER WATERS BY TUE. AS THE MONSOON TROUGH REALIGNS W TO E OVER THE NEXT FEW DAYS...ABUNDANT MOISTURE WILL CONTINUE TO STREAM FROM THE CARIBBEAN ACROSS CENTRAL AMERICA AND ITS INTERIOR MOUNTAINS...WITH WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE TODAY THROUGH MONDAY ACROSS COSTA RICA...NICARAGUA AND PACIFIC COASTAL SECTIONS OF MEXICO. THIS WILL RESULT IN AREAS OF FLASH FLOODS AND MUDSLIDES THROUGH MONDAY. $$ STRIPLING 000 AXPZ20 KNHC 171006 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN JUL 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM N COLOMBIA WWD ACROSS PANAMA AND COSTA RICA TO LOW PRES AT 09.5N86W TO GULF OF TEHUANTEPEC NEAR 15.5N95W TO LOW PRES AT 18N105W. THE MONSOON TROUGH THEN BEGINS IN A ZONE OF BROAD CYCLONIC TURNING NEAR 16N107W TO 11N119W TO 11N132W TO 08N136W...WHERE IT TRANSITIONS TO THE ITCZ TO BEYOND 07N140W. SCATTERED TO NUMEROUS MODERATE TO STRONG WITHIN 180 NM N OF MONSOON TROUGH BETWEEN 86W AND 103W. SCATTERED MODERATE WITHIN 90 NM S OF MONSOON TROUGH BETWEEN 126W AND 131W. ...DISCUSSION... A LONG WAVE TROUGH LIES ALONG THE WESTERN U.S. COAST AND EXTENDS INTO THE FORECAST AREA FROM 32N126W TO 18N136W. THIS TROUGH WILL BE RELOADED WITH NORTHERN STREAM SHORTWAVE ENERGY DROPPING INTO THE BACK SIDE OF THE TROUGH TODAY...SHIFTING THE MEAN TROUGH WESTWARD THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. THIS PERSISTENT TROUGHING ALOFT OVER THE NE PACIFIC IS BLOCKING THE MIGRATION OF THE DEEP LAYER HIGH PRES ASSOCIATED WITH THE SUBTROPICAL HIGH. THE SURFACE HIGH IS EXPECTED TO REMAIN ANCHORED N OF HAWAII ALONG 40N...NW OF ITS CLIMATOLOGICAL POSITION. TRADE WINDS REMAIN LESS THAN 20 KT UNDER THE RELATIVELY WEAK PRES GRADIENT BETWEEN THE ITCZ AND THIS DISPLACED SUBTROPICAL HIGH. THESE CONDITIONS WILL CONTINUE FOR THE NEXT FEW DAYS. MEANWHILE...RECENT SCATTEROMETER PASSES SHOW WIDESPREAD FRESH N TO NW WINDS OFF THE W COAST OF THE BAJA PENINSULA AND AS FAR S AS 21N. THESE WINDS ARE EXPECTED TO DIMINISH TONIGHT THROUGH MON MORNING AS THE SURFACE REFLECTION OF THE NORTHERN STREAM ENERGY REINFORCING THE MEAN TROUGHING ALOFT OFF THE U.S. WEST COAST DISRUPTS THE STRONG PRES GRADIENT OVER NE WATERS. THE AFOREMENTIONED QUASISTATIONARY PATTERN ALOFT IS PART OF AN OMEGA BLOCK CENTERED OVER THE CENTRAL U.S. WHERE A STRONG ANTICYCLONE OVER NEBRASKA IS EXPECTED TO REMAIN THE NEXT FEW DAYS. AN UPPER RIDGE EXTENDS SW FROM THIS ANTICYCLONE THROUGH NW MEXICO AND THE CENTRAL GULF OF CALIFORNIA TO 26N113W TO 18N125W. THIS UPPER RIDGE WILL DRIFT SLOWLY NORTHWESTWARD AS THE TROUGHING TO IS E SHIFTS WESTWARD. A MIDDLE TO UPPER LEVEL CYCLONE WAS OVER N CENTRAL MEXICO MOVING W-NW...AND WAS HELPING TO CREATE DIVERGENT FLOW ALOFT IN ITS WAKE ACROSS THE FAR SW GULF OF MEXICO...WHERE DEEP CONVECTION WAS EXPANDING ACROSS FAR SW PORTIONS OF THE GULF OF CAMPECHE. UPPER LEVEL NE TO ELY FLOW CONTINUES ACROSS THE TROPICAL EPAC S OF 20N FROM CENTRAL AMERICA TO 125W...AND OVERLAY A BROAD ZONE OF FRESH TO STRONG MONSOONAL FLOW E OF 115W. THIS MONSOONAL CIRCULATION EXTENDS FROM A BROAD CYCLONIC FLOW CENTERED NEAR 18N107W E-SE IN A GRADUALLY NARROWING ZONE TO JUST OFFSHORE OF THE PACIFIC COAST OF COSTA RICA. SWLY WINDS CONTINUE TO PROVIDE ABUNDANT MOISTURE AND BROAD SCALE LOW LEVEL CONVERGENCE YIELDING ENHANCED CONVECTION FROM 08N TO 13N BETWEEN 94W AND 111W...WHILE SIMILAR CONDITIONS WERE YIELDING DEEP CONVECTION FROM 03N TO 09N BETWEEN 84W AND 89W. GLOBAL MODELS SHOW A TREND FOR THIS MONSOON TROUGH TO GRADUALLY BECOME MORE W TO E ALIGNED AS IT SINKS SLIGHTLY S DURING THE NEXT FEW DAYS...WITH THE POTENTIAL FOR ONE OR MORE LOW PRESSURE SYSTEMS TO DEVELOP AND INTENSIFY WITHIN THE TROUGH. A 1010 MB SURFACE LOW NEAR 09.5N86W HAS MOVED W ACROSS NRN COSTA RICA IN THE PAST 24 HOURS AND IS EXPECTED TO SHIFT W TO WNW DURING THE NEXT FEW DAYS...WITH DECREASING MOISTURE AND RAINFALL EXPECTED ACROSS HONDURAS AND NORTHERN GUATEMALA ON MONDAY. FRESH WINDS AND SEAS BUILDING 8 TO 10 FT SHOULD BE EXPECTED WITH THIS LOW THROUGH TUE...WITH THE POTENTIAL FOR FURTHER STRENGTHENING. A SECOND SURFACE LOW WAS DETECTED IN THE NW PORTION OF THE MONSOON TROUGH NEAR 18N105W...WITH A BROADER MORE DISTINCT CIRCULATION. THIS BROAD LOW WILL MOVE GRADUALLY W TO WSW OVER THE NEXT FEW DAYS AND SLOWLY WEAKEN OVER COOLER WATERS BY TUE. AS THE MONSOON TROUGH REALIGNS W TO E OVER THE NEXT FEW DAYS...ABUNDANT MOISTURE WILL CONTINUE TO STREAM FROM THE CARIBBEAN ACROSS CENTRAL AMERICA AND ITS INTERIOR MOUNTAINS...WITH WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE TODAY THROUGH MONDAY ACROSS COSTA RICA...NICARAGUA AND PACIFIC COASTAL SECTIONS OF MEXICO. THIS WILL RESULT IN AREAS OF FLASH FLOODS AND MUDSLIDES THROUGH MONDAY. $$ STRIPLING