000 AXPZ20 KNHC 150918 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN JUL 15 2012 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 0715 UTC. ...SPECIAL FEATURES... TROPICAL STORM EMILIA AT 15.7N 136.2W AT 0900 UTC MOVING W AT 14 KT WITH MAXIMUM WINDS 35 KT GUSTS TO 45 KT. SCATTERED MODERATE CONVECTION CAN BE FOUND ONLY WITHIN 75 NM NE QUADRANT OF EMILIA. EMILIA IS FORECAST TO CONTINUE WESTWARD AS IT DIMINISHES TO A TROPICAL DEPRESSION THIS AFTERNOON AND BECOMES A REMNANT LOW PRES BY EARLY MON. IT IS EXPECTED TO CROSS W OF THE FORECAST AREA BY EARLY MON. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. HURRICANE FABIO AT 16.6N 116.7W AT 0900 UTC MOVING W-NW AT 8 KT WITH MAXIMUM WINDS 90 KT GUSTS TO 110 KT. NUMEROUS MODERATE TO STRONG CONVECTION REMAINS WITHIN 75 NM OF CENTER WITH SCATTERED MODERATE CONVECTION ELSEWHERE WITHIN 90 NM OF CENTER EXCEPT WITHIN 180 NM S QUADRANT. FABIO IS LIKELY TO WEAKEN SHORTLY AS IT WILL BE TRAVERSING PROGRESSIVELY COOLER WATERS AND MOVING INTO A DRIER AIRMASS IN ADDITION TO ENCOUNTERING INCREASING SHEAR ATTRIBUTABLE TO THE AMPLIFYING UPPER TROUGH TO ITS NORTH. FABIO IS CURRENTLY FORECAST TO DIMINISH TO A TROPICAL STORM BY MON AFTERNOON AND CONTINUE GRADUALLY WEAKENING THEREAFTER. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 09N82W TO 10N87W TO 08N95W TO 08N110W. THE ITCZ AXIS EXTENDS FROM 12N117W TO 05N133W TO 06N140W. SCATTERED MODERATE TO STRONG CONVECTION LIES WITHIN 180 NM S OF THE AXIS BETWEEN 81W AND 84W. ...DISCUSSION... THE 1035 MB SUBTROPICAL HIGH RESIDES WELL N OF THE FORECAST AREA NEAR 43N142W. A RIDGE EXTENDS SOUTHEASTWARD FROM THE HIGH CENTER THROUGH 32N135W TO 27N119W. THIS RIDGE WILL BE FORCED WESTWARD OVER THE NEXT TWO DAYS AS DEEP LAYER TROUGHING BUILDS BETWEEN FABIO AND AN AMPLIFYING TROUGH OVER CALIFORNIA. THIS TROUGHING WILL DRAW FABIO NORTHWARD INTO COOLER WATERS AND CARRY 25-35 KT OF SOUTHERLY SHEAR OVER THE SYSTEM BY THE END OF THE FORECAST PERIOD EARLY TUE MORNING. THE TIGHTEST PRES GRADIENT OVER FORECAST WATERS S OF THE SUBTROPICAL HIGH WILL SHIFT FROM THE REGION N OF EMILIA AS IT DISSIPATES INTO N CENTRAL WATERS AS THE GRADIENT BETWEEN THE U.S. W COAST TROUGHING AND THE SUBTROPICAL RIDGE BUILDS. FRESH NE WINDS WILL MOVE INTO N CENTRAL WATERS OVERNIGHT SUN NIGHT BUT SHIFT OUT OF FORECAST WATERS BY EARLY TUE AS FABIO...AND THE BEST PRES GRADIENT...SHIFT NORTHWESTWARD. NORTHERLY SWELL WILL KEEP SEAS OVER 8 FT IN N CENTRAL WATERS INTO TUE. PRECIPITABLE WATER IMAGERY SHOWS A DRY AIR MASS HAS WRAPPED AROUND EMILIA...WITH THE EXCEPTION OF ITS EASTERN SIDE WHICH IS ALSO BEGINNING TO BECOME MORE DRY AS EMILIA MOVES WESTWARD AND BREAKS AWAY FROM THE MAIN MOISTURE POOL TO THE EAST. LOW LEVEL MOSITURE IS MORE PLENTIFUL FARTHER S ALONG THE ITCZ AS WELL AS NEAR FABIO AND INTO THE GULF OF CALIFORNIA. SCATTERED MODERATE TO STRONG CONVECTION LIES WITHIN 120 NM OF THE COAST OF MAINLAND MEXICO FROM 19N TO 25N WITHIN THIS MOSITURE RICH REGION. THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENT FLOW BETWEEN AN UPPER RIDGE THAN EXTENDS FROM AN ANTICYCLONE OVER SW NEW MEXICO TO 18N125W AND A WEAK UPPER TROUGH THAT EXTENDS FROM A CYCLONE OVER CENTRAL TEXAS TO 17N105W. CONVECTION LIES ALONG THE EASTERN SIDE OF THE MONSOON TROUGH AS DESCRIBED IN THE SECTION ABOVE AS WELL AS OVER PORTIONS OF COSTA RICA AND PANAMA. THIS CONVECTION IS ASSOCIATED WITH A MAXIMUM OF PRECIPITABLE WATER MAKING ITS WAY WEST FROM THE CARIBBEAN. AN UPPER ANTICYLONE OVER THE SW CARIBBEAN EXTENDS A RIDGE WESTWARD TO 06N90W. LIFT INDUCED BY THE UPPER DIFFLUENCE ASSOCIATED WITH THIS RIDGE AXIS ALOFT IS ENHANCING THE CONVECTION IN PLACE NEAR SOUTHERN CENTRAL AMERICA. $$ SCHAUER