000 AXPZ20 KNHC 172150 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... A 1008 MB SURFACE LOW PRES IS CENTERED NEAR 10N88W WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION TRYING TO ORGANIZE OVER THE AREA WITHIN 240 NM OF THE SW SEMICIRCLE. THIS LOW IS EXPECTED TO MOVE GENERALLY W-NW REACHING NEAR 10N92W LATE MONDAY...AND NEAR 12N96W LATE TUESDAY. MODEL GUIDANCE IS VERY AGGRESSIVE WITH THIS LOW QUICKLY DEEPENING...THUS FORECAST ASSOCIATED WINDS TO INCREASE TO 20 TO 30 KT WITHIN ABOUT 240 NM OF CENTER BY TUESDAY. BOTH THE GFS AND ECMWF ARE SIMILAR IN POSITIONING AT 48 HOURS WITH THE GFS SLIGHTLY MORE AGGRESSIVE ON DEVELOPMENT. THEREFORE THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT COUPLE OF DAYS. ...TROPICAL LOWS... A 1004 MB SURFACE LOW IS CENTERED NEAR 16N107W AND HAS BEEN MOVING S OVER THE PAST 24 HOURS. SCATTERED MODERATE CONVECTION HAS TRENDED DOWNWARD OVER THE PAST 6 HOURS AS ALL THAT REMAINS IS REMNANT DEBRIS CLOUDINESS AND SCATTERED SHOWERS WELL NW OF THE LOW CENTER. THIS LOW IS EXPECTED TO MOVE NW TO NEAR 17N110W MONDAY AND NEAR 19N112W TUESDAY. AS THE LOW MOVES NW IT WILL ENCOUNTER INCREASINGLY COLDER SEA SURFACE WATER SO ITS ENVELOPE OF TIME FOR DEVELOPMENT IS LIMITED. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 08N82W TO 1008 MB LOW PRES NEAR 10N88W TO 18N103W TO 1004 MB LOW PRES NEAR 16N107W TO 11N120W TO 09N136W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N136W TO 08N140W. SCATTERED MODERATE CONVECTION IS FROM 10N TO 15N BETWEEN 97W AND 105W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N TO 11N BETWEEN 115W AND 131W. ...DISCUSSION... A LONGWAVE UPPER LEVEL TROUGH IS ANCHORED ALONG THE W COAST OF NORTH AMERICA WITH ITS MEAN AXIS CONTINUING SOUTHWARD INTO THE DISCUSSION AREA ALONG 32N132W TO A BASE AT 17N140W. 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 118W. A LONGWAVE UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE CENTRAL CONUS ORIGINATING FROM AN ANTICYCLONE MEANDERING OVER KANSAS. AN ASSOCIATED RIDGE AXIS EXTENDS SOUTHWESTWARD OVER NW MEXICO AND INTO THE PACIFIC WATERS NEAR 23N120W. 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 WESTERN CONUS BY EARLY WEDNESDAY AS THE ANTICYCLONE SHIFTS EASTWARD TO OVER THE MID-MISSISSIPPI RIVER VALLEY. AN EMBEDDED UPPER LEVEL CYCLONE IS SHIFTING W ACROSS NW MEXICO CENTERED NEAR 27N106W AND IS TRAILED BY A SHORTWAVE ANTICYCLONE OVER NE MEXICO. THIS IS RESULTING IN AN AREA OF UPPER DIFFLUENCE OVER CENTRAL MEXICO WITH AN AREA OF WIDELY SCATTERED MODERATE CONVECTION OCCURRING FROM 19N-24N BETWEEN 94W-103W. AN UPPER LEVEL TROUGH EXTENDS W-SW ACROSS THE CARIBBEAN FROM PUERTO RICO TO AN UPPER CYCLONE AT 11N82W. 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 06N124W WITH A RIDGE EXTENDING E...ROUGHLY OVER THE LOWER LEVEL MONSOON TROUGH AXIS...TO A CREST AT 08N109W. THUS...THE UPPER LEVELS OF THE DEEP TROPICS ARE SOMEWHAT DIFFLUENT OVER MOST OF CENTRAL AMERICA...AND OVER THE TROPICAL PACIFIC E OF 112W. CONVECTION CONTINUES TO FLARE IN A BROAD ZONE N OF 04N E OF 106W. ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE FOR THE NEXT 12 HOURS TO PULSE AT 15-20 KT ALONG THE W COAST OF BAJA CALIFORNIA AND GRADUALLY DIMINISH EARLY MONDAY. REINFORCING SW SWELL HAS CROSSED THE EQUATOR BETWEEN 80W AND 110W AND IS EXPECTED TO REMAIN S OF 10N THROUGH EARLY MONDAY. SOUTHWESTERLY MONSOONAL WINDS ARE EXPECTED TO DIMINISH SOME AS THE SURFACE LOWS MOVE GENERALLY WESTWARD. $$ HUFFMAN 000 AXPZ20 KNHC 172150 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... A 1008 MB SURFACE LOW PRES IS CENTERED NEAR 10N88W WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION TRYING TO ORGANIZE OVER THE AREA WITHIN 240 NM OF THE SW SEMICIRCLE. THIS LOW IS EXPECTED TO MOVE GENERALLY W-NW REACHING NEAR 10N92W LATE MONDAY...AND NEAR 12N96W LATE TUESDAY. MODEL GUIDANCE IS VERY AGGRESSIVE WITH THIS LOW QUICKLY DEEPENING...THUS FORECAST ASSOCIATED WINDS TO INCREASE TO 20 TO 30 KT WITHIN ABOUT 240 NM OF CENTER BY TUESDAY. BOTH THE GFS AND ECMWF ARE SIMILAR IN POSITIONING AT 48 HOURS WITH THE GFS SLIGHTLY MORE AGGRESSIVE ON DEVELOPMENT. THEREFORE THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT COUPLE OF DAYS. ...TROPICAL LOWS... A 1004 MB SURFACE LOW IS CENTERED NEAR 16N107W AND HAS BEEN MOVING S OVER THE PAST 24 HOURS. SCATTERED MODERATE CONVECTION HAS TRENDED DOWNWARD OVER THE PAST 6 HOURS AS ALL THAT REMAINS IS REMNANT DEBRIS CLOUDINESS AND SCATTERED SHOWERS WELL NW OF THE LOW CENTER. THIS LOW IS EXPECTED TO MOVE NW TO NEAR 17N110W MONDAY AND NEAR 19N112W TUESDAY. AS THE LOW MOVES NW IT WILL ENCOUNTER INCREASINGLY COLDER SEA SURFACE WATER SO ITS ENVELOPE OF TIME FOR DEVELOPMENT IS LIMITED. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 08N82W TO 1008 MB LOW PRES NEAR 10N88W TO 18N103W TO 1004 MB LOW PRES NEAR 16N107W TO 11N120W TO 09N136W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N136W TO 08N140W. SCATTERED MODERATE CONVECTION IS FROM 10N TO 15N BETWEEN 97W AND 105W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N TO 11N BETWEEN 115W AND 131W. ...DISCUSSION... A LONGWAVE UPPER LEVEL TROUGH IS ANCHORED ALONG THE W COAST OF NORTH AMERICA WITH ITS MEAN AXIS CONTINUING SOUTHWARD INTO THE DISCUSSION AREA ALONG 32N132W TO A BASE AT 17N140W. 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 118W. A LONGWAVE UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE CENTRAL CONUS ORIGINATING FROM AN ANTICYCLONE MEANDERING OVER KANSAS. AN ASSOCIATED RIDGE AXIS EXTENDS SOUTHWESTWARD OVER NW MEXICO AND INTO THE PACIFIC WATERS NEAR 23N120W. 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 WESTERN CONUS BY EARLY WEDNESDAY AS THE ANTICYCLONE SHIFTS EASTWARD TO OVER THE MID-MISSISSIPPI RIVER VALLEY. AN EMBEDDED UPPER LEVEL CYCLONE IS SHIFTING W ACROSS NW MEXICO CENTERED NEAR 27N106W AND IS TRAILED BY A SHORTWAVE ANTICYCLONE OVER NE MEXICO. THIS IS RESULTING IN AN AREA OF UPPER DIFFLUENCE OVER CENTRAL MEXICO WITH AN AREA OF WIDELY SCATTERED MODERATE CONVECTION OCCURRING FROM 19N-24N BETWEEN 94W-103W. AN UPPER LEVEL TROUGH EXTENDS W-SW ACROSS THE CARIBBEAN FROM PUERTO RICO TO AN UPPER CYCLONE AT 11N82W. 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 06N124W WITH A RIDGE EXTENDING E...ROUGHLY OVER THE LOWER LEVEL MONSOON TROUGH AXIS...TO A CREST AT 08N109W. THUS...THE UPPER LEVELS OF THE DEEP TROPICS ARE SOMEWHAT DIFFLUENT OVER MOST OF CENTRAL AMERICA...AND OVER THE TROPICAL PACIFIC E OF 112W. CONVECTION CONTINUES TO FLARE IN A BROAD ZONE N OF 04N E OF 106W. ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE FOR THE NEXT 12 HOURS TO PULSE AT 15-20 KT ALONG THE W COAST OF BAJA CALIFORNIA AND GRADUALLY DIMINISH EARLY MONDAY. REINFORCING SW SWELL HAS CROSSED THE EQUATOR BETWEEN 80W AND 110W AND IS EXPECTED TO REMAIN S OF 10N THROUGH EARLY MONDAY. SOUTHWESTERLY MONSOONAL WINDS ARE EXPECTED TO DIMINISH SOME AS THE SURFACE LOWS MOVE GENERALLY WESTWARD. $$ HUFFMAN