000 AXPZ20 KNHC 181010 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON JUL 18 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 0900 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... A 1007 MB SURFACE LOW PRES WAS ESTIMATED NEAR 10N90W WITH A LARGE BURST OF CONVECTION DEVELOPING WITHIN 210 NM ACROSS THE S SEMICIRCLE OVERNIGHT...WHILE A DEEP LAYERED ELY WIND SURGE MOVED OFF OF CENTRAL AMERICA OVERNIGHT AND ACROSS THE N PORTIONS OF THIS CIRCULATION...KICKING OFF A LARGE CLUSTER OF STRONG CONVECTION FROM 150 TO 360 NM TO THE NW OF THE CENTER. NELY WINDS ALOFT CONTINUE ACROSS THE REGION AND ARE IMPARTING VERY LIGHT WIND SHEAR ALOFT. SATELLITE IMAGERY THIS MORNING SUGGESTS AN IMPROVING MID LEVEL CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW...OCCURRING WITHIN THE E PORTIONS OF THE EPAC MONSOON TROUGH. THE SURFACE LOW IS FORECAST TO MOVE W TO WNW OVER THE NEXT FEW DAYS...AND COULD INTENSIFY INTO A TROPICAL DEPRESSION OR TROPICAL STORM WITHIN THE NEXT 24-36 HOURS. A 0600 UTC SHIP OBSERVATION ABOUT 60 NM N OF THE ESTIMATED CENTER REPORTED ELY WINDS AT 31 KT...WHILE A 0334 UTC PARTIAL ASCAT PASS REVEALED SELY WINDS OF 20 TO 25 KT ACROSS THE NE QUADRANT. ATMOSPHERIC AND OCEANIC CONDITIONS REMAIN FAVORABLE FOR THIS SYSTEM TO INTENSIFY INTO A TROPICAL CYCLONE WITHIN THE NEXT 24-36 HOURS...AS ALSO INDICATED BY LATEST GLOBAL MODELS GUIDANCE...AND RAPID INTENSIFICATION IS SUGGESTED BY SOME OF THE MODELS. SEAS ACROSS THE N SEMICIRCLE HAVE BEGUN TO REACH 10 FT OVERNIGHT AND WILL BUILD STEADILY TO 15 FT OR HIGHER DURING THE NEXT 36-48 HOURS. ...TROPICAL LOWS... A 1007 MB SURFACE LOW IS CENTERED NEAR 16N108W...EMBEDDED WITHIN THE NW PORTION OF THE MONSOON TROUGH ACROSS THE TROPICAL EPAC. ALTHOUGH THE SURFACE LOW IS CENTERED UNDER A WELL DEFINED LOW TO MID LEVEL CYCLONIC CIRCULATION...DRY AND STABLE AIR IS BEING ENTRAINED ACROSS W AND SW PORTIONS. THE LOW IS FORECAST TO DRIFT W OVER THE NEXT FEW DAYS AND OVER COOLER WATER TEMPERATURES... AND WILL GRADUALLY WEAKEN AND LIKELY DISSIPATE BY 72 HOURS. CLUSTERS OF STRONG CONVECTION CONTINUE TO FLARE NEAR THE CENTER THIS MORNING BUT ARE GENERALLY ISOLATED. WINDS TO 20 KT ARE LIKELY OCCURRING IN THE SW QUADRANT AND ALONG THE MEXICAN COASTAL WATERS IN THE NE SEMICIRCLE OF THIS LOW. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE SW CARIBBEAN ALONG ABOUT 10N ACROSS CENTRAL COSTA RICA TO 09N87W TO LOW PRES NEAR 10N90W TO 15N96W TO LOW PRES NEAR 16N108W TO 12N111W TO 11N120W TO 08N138W... WHERE IT TRANSITIONS TO THE INTERTROPICAL CONVERGENCE ZONE EXTENDING BEYOND 07N140W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM OF THE MEXICAN COAST BETWEEN 91W AND 106W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM S OF TROUGH AXIS BETWEEN 113W AND 126W. ...DISCUSSION... A LONGWAVE UPPER LEVEL TROUGH REMAINS STATIONARY ALONG THE W COAST OF NORTH AMERICA WITH ITS MEAN AXIS CONTINUING SOUTHWARD INTO THE DISCUSSION AREA ALONG 32N133W TO A BASE AT 15N139W. AN EMBEDDED SHORTWAVE MID-LEVEL TROUGH AND LOW IS CENTERED NEAR 25N128W AND IS ACCOMPANIED BY UPPER MOISTURE AND A WEAK COLD FRONT EXPECTED TO REMAIN NORTH OF THE AREA OVER THE NEXT 24-48 HOURS. OTHERWISE THE UPPER LEVELS ARE VERY DRY TO THE NORTH OF 14N AND WEST OF 119W. A BROAD UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE CENTRAL CONUS ORIGINATING FROM AN ANTICYCLONE MEANDERING OVER EASTERN KANSAS. AN ASSOCIATED RIDGE AXIS EXTENDS SOUTHWESTWARD OVER NW MEXICO AND INTO THE PACIFIC WATERS NEAR 29N117W. THIS RIDGE WILL CONTINUE TO BLOCK THE FORWARD ADVANCE OF THE PREVIOUSLY DESCRIBED UPPER LEVEL TROUGHS THROUGH TUESDAY. THEREAFTER A STRONG SHORTWAVE TROUGH IS EXPECTED TO MOVE THE LONGWAVE AXIS OVER THE NW CONUS BY EARLY WEDNESDAY AS THE ANTICYCLONE SHIFTS EASTWARD TO OVER THE MID-MISSISSIPPI RIVER VALLEY. AN UPPER LEVEL CYCLONE MOVING UNDERNEATH THE UPPER RIDGE WAS SHIFTING NW ACROSS NW MEXICO CENTERED NEAR 30N108W AND IS TRAILED BY A SHORTWAVE ANTICYCLONE OVER NE MEXICO. A TUTT AXIS EXTENDS W-SW ACROSS THE CARIBBEAN FROM HISPANIOLA TO AN UPPER CYCLONE AT 13N82W. AN UPPER LEVEL RIDGE EXTENDS SW FROM NW VENEZUELA TO A CREST ALONG THE PACIFIC COAST OF COLOMBIA. AN TROPICAL UPPER ANTICYLONE IS CENTERED NEAR 07N123W WITH A RIDGE EXTENDING EASTWARD...ROUGHLY OVER THE LOWER LEVEL MONSOON TROUGH AXIS...TO A CREST AT 08N108W. THUS...THE UPPER LEVELS OF THE DEEP TROPICS ARE SOMEWHAT DIFFLUENT OVER MOST OF CENTRAL AMERICA...AND OVER THE TROPICAL PACIFIC E OF 110W. CONVECTION CONTINUES TO FLARE IN A BROAD ZONE N OF 06N BETWEEN 85W AND 100W. ELSEWHERE AT THE SURFACE...REINFORCING LONG PERIOD SW SWELL HAS CROSSED THE EQUATOR AND WILL PROPAGATE TO THE CENTRAL AMERICA AND MEXICO COASTS TODAY THROUGH TUESDAY. SOUTHWESTERLY MONSOONAL WINDS ARE EXPECTED TO DIMINISH SOME DURING THE NEXT 48 HOURS AS THE THE SURFACE LOWS MOVE GENERALLY WEST-NORTHWESTWARD AND BEGIN TO BREAK UP THE MONSOON TROUGH INTO SHORTER SEGMENTS ACCOMPANIED BY WEAKER WIND FLOW. $$ STRIPLING 000 AXPZ20 KNHC 181010 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON JUL 18 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 0900 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...SPECIAL FEATURES... A 1007 MB SURFACE LOW PRES WAS ESTIMATED NEAR 10N90W WITH A LARGE BURST OF CONVECTION DEVELOPING WITHIN 210 NM ACROSS THE S SEMICIRCLE OVERNIGHT...WHILE A DEEP LAYERED ELY WIND SURGE MOVED OFF OF CENTRAL AMERICA OVERNIGHT AND ACROSS THE N PORTIONS OF THIS CIRCULATION...KICKING OFF A LARGE CLUSTER OF STRONG CONVECTION FROM 150 TO 360 NM TO THE NW OF THE CENTER. NELY WINDS ALOFT CONTINUE ACROSS THE REGION AND ARE IMPARTING VERY LIGHT WIND SHEAR ALOFT. SATELLITE IMAGERY THIS MORNING SUGGESTS AN IMPROVING MID LEVEL CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW...OCCURRING WITHIN THE E PORTIONS OF THE EPAC MONSOON TROUGH. THE SURFACE LOW IS FORECAST TO MOVE W TO WNW OVER THE NEXT FEW DAYS...AND COULD INTENSIFY INTO A TROPICAL DEPRESSION OR TROPICAL STORM WITHIN THE NEXT 24-36 HOURS. A 0600 UTC SHIP OBSERVATION ABOUT 60 NM N OF THE ESTIMATED CENTER REPORTED ELY WINDS AT 31 KT...WHILE A 0334 UTC PARTIAL ASCAT PASS REVEALED SELY WINDS OF 20 TO 25 KT ACROSS THE NE QUADRANT. ATMOSPHERIC AND OCEANIC CONDITIONS REMAIN FAVORABLE FOR THIS SYSTEM TO INTENSIFY INTO A TROPICAL CYCLONE WITHIN THE NEXT 24-36 HOURS...AS ALSO INDICATED BY LATEST GLOBAL MODELS GUIDANCE...AND RAPID INTENSIFICATION IS SUGGESTED BY SOME OF THE MODELS. SEAS ACROSS THE N SEMICIRCLE HAVE BEGUN TO REACH 10 FT OVERNIGHT AND WILL BUILD STEADILY TO 15 FT OR HIGHER DURING THE NEXT 36-48 HOURS. ...TROPICAL LOWS... A 1007 MB SURFACE LOW IS CENTERED NEAR 16N108W...EMBEDDED WITHIN THE NW PORTION OF THE MONSOON TROUGH ACROSS THE TROPICAL EPAC. ALTHOUGH THE SURFACE LOW IS CENTERED UNDER A WELL DEFINED LOW TO MID LEVEL CYCLONIC CIRCULATION...DRY AND STABLE AIR IS BEING ENTRAINED ACROSS W AND SW PORTIONS. THE LOW IS FORECAST TO DRIFT W OVER THE NEXT FEW DAYS AND OVER COOLER WATER TEMPERATURES... AND WILL GRADUALLY WEAKEN AND LIKELY DISSIPATE BY 72 HOURS. CLUSTERS OF STRONG CONVECTION CONTINUE TO FLARE NEAR THE CENTER THIS MORNING BUT ARE GENERALLY ISOLATED. WINDS TO 20 KT ARE LIKELY OCCURRING IN THE SW QUADRANT AND ALONG THE MEXICAN COASTAL WATERS IN THE NE SEMICIRCLE OF THIS LOW. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE SW CARIBBEAN ALONG ABOUT 10N ACROSS CENTRAL COSTA RICA TO 09N87W TO LOW PRES NEAR 10N90W TO 15N96W TO LOW PRES NEAR 16N108W TO 12N111W TO 11N120W TO 08N138W... WHERE IT TRANSITIONS TO THE INTERTROPICAL CONVERGENCE ZONE EXTENDING BEYOND 07N140W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM OF THE MEXICAN COAST BETWEEN 91W AND 106W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM S OF TROUGH AXIS BETWEEN 113W AND 126W. ...DISCUSSION... A LONGWAVE UPPER LEVEL TROUGH REMAINS STATIONARY ALONG THE W COAST OF NORTH AMERICA WITH ITS MEAN AXIS CONTINUING SOUTHWARD INTO THE DISCUSSION AREA ALONG 32N133W TO A BASE AT 15N139W. AN EMBEDDED SHORTWAVE MID-LEVEL TROUGH AND LOW IS CENTERED NEAR 25N128W AND IS ACCOMPANIED BY UPPER MOISTURE AND A WEAK COLD FRONT EXPECTED TO REMAIN NORTH OF THE AREA OVER THE NEXT 24-48 HOURS. OTHERWISE THE UPPER LEVELS ARE VERY DRY TO THE NORTH OF 14N AND WEST OF 119W. A BROAD UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE CENTRAL CONUS ORIGINATING FROM AN ANTICYCLONE MEANDERING OVER EASTERN KANSAS. AN ASSOCIATED RIDGE AXIS EXTENDS SOUTHWESTWARD OVER NW MEXICO AND INTO THE PACIFIC WATERS NEAR 29N117W. THIS RIDGE WILL CONTINUE TO BLOCK THE FORWARD ADVANCE OF THE PREVIOUSLY DESCRIBED UPPER LEVEL TROUGHS THROUGH TUESDAY. THEREAFTER A STRONG SHORTWAVE TROUGH IS EXPECTED TO MOVE THE LONGWAVE AXIS OVER THE NW CONUS BY EARLY WEDNESDAY AS THE ANTICYCLONE SHIFTS EASTWARD TO OVER THE MID-MISSISSIPPI RIVER VALLEY. AN UPPER LEVEL CYCLONE MOVING UNDERNEATH THE UPPER RIDGE WAS SHIFTING NW ACROSS NW MEXICO CENTERED NEAR 30N108W AND IS TRAILED BY A SHORTWAVE ANTICYCLONE OVER NE MEXICO. A TUTT AXIS EXTENDS W-SW ACROSS THE CARIBBEAN FROM HISPANIOLA TO AN UPPER CYCLONE AT 13N82W. AN UPPER LEVEL RIDGE EXTENDS SW FROM NW VENEZUELA TO A CREST ALONG THE PACIFIC COAST OF COLOMBIA. AN TROPICAL UPPER ANTICYLONE IS CENTERED NEAR 07N123W WITH A RIDGE EXTENDING EASTWARD...ROUGHLY OVER THE LOWER LEVEL MONSOON TROUGH AXIS...TO A CREST AT 08N108W. THUS...THE UPPER LEVELS OF THE DEEP TROPICS ARE SOMEWHAT DIFFLUENT OVER MOST OF CENTRAL AMERICA...AND OVER THE TROPICAL PACIFIC E OF 110W. CONVECTION CONTINUES TO FLARE IN A BROAD ZONE N OF 06N BETWEEN 85W AND 100W. ELSEWHERE AT THE SURFACE...REINFORCING LONG PERIOD SW SWELL HAS CROSSED THE EQUATOR AND WILL PROPAGATE TO THE CENTRAL AMERICA AND MEXICO COASTS TODAY THROUGH TUESDAY. SOUTHWESTERLY MONSOONAL WINDS ARE EXPECTED TO DIMINISH SOME DURING THE NEXT 48 HOURS AS THE THE SURFACE LOWS MOVE GENERALLY WEST-NORTHWESTWARD AND BEGIN TO BREAK UP THE MONSOON TROUGH INTO SHORTER SEGMENTS ACCOMPANIED BY WEAKER WIND FLOW. $$ STRIPLING