000 AXNT20 KNHC 050555 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUL 05 2014 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... HURRICANE ARTHUR IS CENTERED NEAR 42.3N 67.6W AT 05/0600 UTC OR ABOUT 115 NM SW OF YARMOUTH NOVA SCOTIA MOVING NE AT 27 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SCATTERED TO NUMEROUS MODERATE TO STRONG CONVECTION IS LOCATED N OF THE CENTER WITHIN 55 NM EITHER SIDE OF A LINE FROM THE MAINE COAST AT 44N69W TO 41.5N66.5W. SEE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/ WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 18N24W TO 08N27W AND IS MOVING W AT 20 KT. A STRONG SAHARAN AIR LAYER SIGNAL IS NOTED ON METEOSAT-9 IMAGERY TO THE WEST AND NORTH OF THE WAVE THAT CONTINUES TO RESULT IN AN OVERALL LACK OF ANY SIGNIFICANT CONVECTION IN THE VICINITY OF THE WAVE AXIS. A TROPICAL WAVE EXTENDS FROM 21N58W TO 09N57W AND IS MOVING W AT 15-20 KT. THE WAVE IS EASY TO IDENTIFY ON THE LATEST INFRARED SATELLITE IMAGERY AND EXHIBITS A CLASSIC WAVE PATTERN. THERE IS NO SIGNIFICANT DEEP CONVECTION DUE TO THE WAVE REMAINING EMBEDDED WITHIN A STRONG SAHARAN AIR LAYER. A TROPICAL WAVE EXTENDS ALONG 76W/77W FROM 11N TO 21N AND IS MOVING W AT 15-20 KT. THE WAVE IS CURRENTLY MOVING BENEATH THE WESTERN PERIPHERY OF AN UPPER LEVEL LOW CENTERED NEAR 18N74W. THERE IS NO SIGNIFICANT CONVECTION DUE TO THE RELATIVE STABILITY OF THE UPPER LEVEL FLOW AND DRY CONDITIONS SURROUNDING THE WAVE. A TROPICAL WAVE EXTENDS ALONG 94W/95W FROM 09N TO 22N AND IS MOVING W AT 15 KT. A MIDDLE/UPPER LEVEL TROUGH W OF THE WAVE AXIS IS SUPPORTING SCATTERED MODERATE TO STRONG CONVECTION S OF 23.5N W OF 90W INCLUDING THE BAY OF CAMPECHE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 08N25W TO 07N37W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N37W TO 04N53W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS LOCATED ALONG THE AFRICAN COAST FROM 06.5N TO 10N AND CONTINUES OFFSHORE UP TO 180 NM AND FROM 06N TO 08N BETWEEN 32W AND 34W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE/UPPER LEVEL TROUGH OVER THE WESTERN GULF HAS ITS AXIS EXTENDING THROUGH THE CENTRAL LOUISIANA COAST TO 27N96W TO 18N98W. RIDGING ALOFT COVERS THE GULF ROUGHLY S OF 27N E OF 95W. AT THE SURFACE A TROUGH IS LOCATED FROM NEAR JACKSONVILLE FLORIDA TO 27N85W. BROKEN LAYERED CLOUDS ARE LOCATED OVER THE FLORIDA PENINSULA N OF 27.5N. A STATIONARY FRONT CUTS ACROSS THE FLORIDA PANHANDLE E OF 86.5W. A 1022 MB HIGH IS CENTERED NEAR 27.5N90.5W. CARIBBEAN SEA... THE RIDGING NOTED ALOFT IN THE GULF SECTION EXTENDS SOUTHWARD ACROSS THE CARIBBEAN W OF 78W AND OVER MOST OF CENTRAL AMERICA. AN UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED OVER THE N CENTRAL CARIBBEAN NEAR 18N74W. A TROUGH AXIS EXTENDS FROM THE CIRCULATION SOUTHWARD TO 11N79W. MODERATE SOUTHERLY WINDS ALOFT COVER THE EASTERN THIRD OF THE CARIBBEAN. INCREASING CLOUDS COVER THE LEEWARD AND WINDWARD ISLANDS DUE TO THE APPROACHING TROPICAL WAVE. ...HISPANIOLA... A FEW ISOLATED SHOWERS ARE LOCATED OVER HISPANIOLA EARLY THIS MORNING. THE PRESENCE OF AN UPPER LOW CENTERED NEAR 18N74W WILL KEEP THE ISLAND IN A FAVORABLE ENVIRONMENT ALOFT TO SUPPORT ANY CONVECTION THAT DOES INITIATE THROUGH THE WEEKEND. ATLANTIC OCEAN... A MIDDLE/UPPER LEVEL TROUGH AXIS CUTS ACROSS THE WESTERN ATLANTIC THROUGH 32N57W TO 25N65W TO 20N74W. AT THE SURFACE A TROUGH IS LOCATED FROM 32N56W TO 26N62W WITH SCATTERED SHOWERS LOCATED UP TO TWO DEGREES EITHER SIDE OF THE TROUGH. A WELL- DEFINED AND LARGE MIDDLE/UPPER LEVEL ANTICYCLONIC CIRCULATION IS POSITIONED NEAR 17N57W AND COVERS THE AREA ROUGHLY FROM 08N TO 27N BETWEEN 40W AND 65W. WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE IN THIS AREA. MOVING DOWNSTREAM A MIDDLE/UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED NEAR 28N42W AND IS ABOUT 12 TO 15 DEGREES IN DIAMETER. BROAD RIDGING ALOFT COVERS THE EASTERN ATLANTIC FROM 10N TO 25N E OF 25W INTO AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ CAB