000 AXPZ20 KNHC 051544 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON AUG 04 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...SPECIAL FEATURES... MAJOR HURRICANE ISELLE CENTERED NEAR 16.0N 139.5W AT 05/0900 UTC MOVING WEST OR 270 DEGREES AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB. ISELLE IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO 135 KT. NUMEROUS MODERATE TO STRONG CONVECTION EXISTS WITHIN 120 NM OF CENTER OF ISELLE. GIVEN THE STRONG WINDS AND MODEST FORWARD SPEED OF ISELLE...SEAS ARE ESTIMATED TO BE NEAR 36 FT IN THE NORTH CENTRAL PORTION OF THE STORM. THE OFFICIAL INTENSITY FORECAST CALLS FOR ISELLE TO MAINTAIN HURRICANE STATUS THROUGH THURSDAY AS IT MOVES ACROSS THE CENTRAL PACIFIC. ISELLE IS FORECAST TO CROSS 140W LATER TODAY. PLEASE SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. TROPICAL STORM JULIO IS CENTERED NEAR 14.0N 124.7W AT 05/1500 UTC OR ABOUT 995 NM...1845 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MOVING WEST OR 275 DEGREES AT 11 KT. ESTIMATED CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. NUMEROUS MODERATE TO STRONG CONVECTION EXISTS WITHIN 180 NM SW SEMICIRCLE OF CENTER. SCATTERED MODERATE TO STRONG CONVECTION IS LOCATED WITHIN 60 NM NE SEMICIRCLE. JULIO IS EXPECTED TO CONTINUE MOVING TOWARD THE WEST AND FAR FROM LAND DURING THE NEXT COUPLE OF DAYS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS AND JULIO IS EXPECTED TO BECOME A HURRICANE ON WEDNESDAY. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. A 1007 MB LOW IS LOCATED NEAR 11N99W...EMBEDDED ON THE MONSOON TROUGH. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 240 NM NW QUADRANT OF CENTER. UPPER-LEVEL WINDS ARE EXPECTED TO GRADUALLY IMPROVE OVER THE NEXT FEW DAYS WHILE THE SYSTEM MOVES WEST- NORTHWESTWARD AT 10-15 KT. THE LATEST NHC TROPICAL WEATHER OUTLOOK GIVES THIS LOW PRES A MEDIUM CHANGE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 07N78W TO 06N80W TO A LOW PRES NEAR 11N99W 1007 MB TO 07N110W. THE ITCZ CONTINUES FROM 07N110W TO 11N120W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 07N BETWEEN 78W AND 82W...AND FROM 11N TO 15N BETWEEN 91W AND 93W. ...DISCUSSION... MAJOR HURRICANE ISELLE AND TROPICAL STORM JULIO ARE THE TWO BIG FEATURES ACROSS THE FORECAST REGION TODAY. SEE SPECIAL FEATURES FOR DETAILS. A SURFACE RIDGE IS N OF 20N. FAIRLY DRY CONDITIONS PERSIST ACROSS MUCH OF THE AREA N OF 20N W OF 115W. A FAIRLY MOIST ENVIRONMENT IS TO THE SOUTH OF THE RIDGE DUE TO THE PRESENCE OF TROPICAL CYCLONES ISELLE AND JULIO. LONG PERIOD SWLY SWELLS FROM THE SOUTHERN HEMISPHERE WILL CONTINUE TO IMPACT MAINLY THE WATERS E OF 110W...BUILDING SEAS TO AROUND 8 FT FROM 02N TO 12N BETWEEN 90W AND 110W...AND S OF 03N E OF 80W TO A LINE FROM 03N83W TO 3.4S90W. SEAS ARE FORECAST TO SUBSIDE BELOW 8 FT ACROSS THESE AREAS IN ABOUT 6-12 HOURS. NO SIGNIFICANT GAP WIND EVENTS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE N PART OF THE FORECAST REGION...MAINLY N OF 20N. A RIDGE ANCHORED BY AN ANTICYCLONE JUST S OF THE HAWAIIAN ISLANDS REACHES THE FAR NW CORNER OF THE AREA. AN UPPER-LEVEL TROUGH EXTENDS FROM A CUT-OFF LOW NEAR 35N124W TO NEAR 26N135W. A BROAD ANTICYCLONIC CIRCULATION IS INLAND MEXICO NEAR 27N106W WITH A RIDGE EXTENDING TOWARD THE SW TO THE E OF ISELLE NEAR 16N135W. MODERATE TO STRONG ELY FLOW ALOFT IS NOTED ON THE SOUTHERN PERIPHERY OF THE RIDGE. THESE WINDS ARE IMPACTING T.S. JULIO. AN INVERTED TROUGH FROM THE SW GULF OF MEXICO EXTENDS INTO THE EPAC TO NEAR 12N100W WHILE A RIDGE DOMINATES NORTHERN CENTRAL AMERICA. UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE IS HELPING TO INDUCE CONVECTION FROM 11N TO 15N BETWEEN 91W AND 93W. NE TO E WINDS ALOFT ARE OBSERVER ACROSS THE REMAINDER OF THE FORECAST REGION. $$ GR