000 AXNT20 KNHC 081800 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU SEP 08 2011 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURES... HURRICANE KATIA IS CENTERED NEAR 34.2N 70.0W AT 08/1800 UTC OR ABOUT 330 MI...535 KM WNW OF BERMUDA MOVING N AT 14 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 973 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/ WTNT22 KNHC FOR MORE DETAILS. SCATTERED SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 32N-37N BETWEEN 66W-72W. LARGE SWELLS GENERATED BY HURRICANE KATIA WILL CONTINUE TO AFFECT MOST OF THE EAST COAST OF THE UNITED STATES...BERMUDA...THE GREATER ANTILLES...AND EAST FACING BEACHES OF THE BAHAMAS DURING THE NEXT FEW DAYS. THESE SWELLS ARE LIKELY TO CAUSE LIFE THREATENING SURF AND RIP CURRENT CONDITIONS. PLEASE CONSULT PRODUCTS ISSUED BY LOCAL NATIONAL WEATHER SERVICE OFFICES FOR MORE INFORMATION. GLOBAL MODELS INDICATE THAT KATIA WILL REMAIN A POWERFUL CYCLONE OVER THE NEXT DAY OR SO. THE FORECAST TAKES THE REMNANTS OF KATIA NORTH OF THE BRITISH ISLES IN ABOUT FOUR DAYS. TROPICAL STORM NATE IS CENTERED NEAR 19.9N 92.4W AT 08/1800 UTC OR ABOUT 125 MI...200 KM W OF CAMPECHE AND ABOUT 175 MI...285 KM NE OF COATZACOALCOS MEXICO MOVING SE AT 1 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT5/ WTNT25 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION REMAINS SW OF THE CENTER OVER THE W BAY OF CAMPECHE TO INLAND OVER MEXICO S OF 21N BETWEEN 91W-96W. THE OUTER CONVECTION FROM NATE ALSO COVERS IMMEDIATE COASTAL WATERS OF THE EASTERN COAST OF THE YUCATAN PENINSULA AND IN THE GULF OF HONDURAS. NATE IS CURRENTLY LOCATED IN AN ENVIRONMENT OF LIGHT TO MODERATE NORTHEASTERLY SHEAR. NATE IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES WITH ISOLATED MAXIMUM AMOUNTS OF 8 INCHES OVER THE MEXICAN STATES OF CAMPECHE... TABASCO...AND SOUTHERN VERACRUZ. A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS ALONG THE IMMEDIATE COAST IN THE WARNING AREA. THE SHEAR IS FORECAST TO LESSEN DURING THE NEXT DAY OR SO...WHICH SHOULD ALLOW FOR GRADUAL STRENGTHENING. TROPICAL STORM MARIA IS CENTERED NEAR 13.0N 52.0W AT 08/1800 UTC OR ABOUT 605 MI...975 KM E OF THE WINDWARD ISLANDS MOVING W AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT4/ WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. MARIA HAS A RATHER DISORGANIZED APPEARANCE ON SATELLITE IMAGERY. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 12N-17N BETWEEN 45W-55W. MARIA IS SOUTH OF A PERSISTENT AND LARGE SUBTROPICAL RIDGE THAT EXTENDS WESTWARD ACROSS THE ATLC. THIS STEERING PATTERN CALLS FOR A WEST TO WEST-NORTHWEST TRACK OVER THE NEXT TWO TO THREE DAYS. AFTER THAT...A WEAKER RIDGE NORTH OF THE CYCLONE IS EXPECTED TO ALLOW A MORE NORTHWESTWARD TRACK AT A SOMEWHAT SLOWER FORWARD SPEED. GUIDANCE IS IN VERY GOOD AGREEMENT...AND MOST OF THE MODELS ARE CLUSTERED HAVING MARIA OVER OR JUST TO THE NORTH OF THE CENTRAL BAHAMAS IN FIVE DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS WSW OF CAPE VERDE ISLANDS ANALYZED FROM 17N27W TO 9N28W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY AND IS WELL DEFINED IN THE LOW LEVEL CLOUD FIELD ON VISIBLE SATELLITE IMAGERY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 120 NM ON EITHER SIDE OF THE WAVE AXIS. TROPICAL WAVE IS JUST EAST OF DOMINICAN REPUBLIC IS ANALYZED FROM 23N68W TO 15N68W MOVING WNW 15-20 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS AND THUNDERSTORMS ARE AFFECTING THE NORTH CENTRAL CARIBBEAN N OF 15N BETWEEN 67W-81W...AND THE ATLC WATERS N OF PUERTO RICO FROM 19N-25N BETWEEN 60W-68W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED OVER AFRICA INTO THE E TROPICAL ATLC ACROSS THE NORTHERN COAST OF MAURITANIA NEAR 20N16W TO 17N20W. THE MONSOON TROUGH AND ITCZ AXIS HAS BEEN DISRUPTED BY THE LACK OF CONFLUENCE IN THE TRADE WINDS AND THE PRESENCE OF TROPICAL STORM MARIA. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 170 NM OF COAST OF LIBERIA...SIERRA LEONE...AND GUINEA. SIMILAR ACTIVITY OF FROM 1N-8N BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY CONCERN THIS AFTERNOON IS TROPICAL STORM NATE...SEE SPECIAL FEATURES SECTION ABOVE. A SHARP UPPER TROUGH MOVES ACROSS THE FAR EAST CONUS SUPPORTING A NEARLY STATIONARY FRONTAL BOUNDARY EXTENDS ACROSS CENTRAL FLORIDA INTO THE GULF WATERS ALONG TAMPA BAY TO NEAR 25N86W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 70 NM EITHER SIDE OF THE FRONT. VERY DRY AIR AND SUBSIDENCE ALOFT COVERS THE NW AND N CENTRAL BASINS ...GIVING THIS REGION REMARKABLE CLEAR SKIES AND FAIR WEATHER CONDITIONS NW OF A LINE FROM THE COAST OF FLORIDA NEAR 30N83W THE COAST OF MEXICO NEAR TAMPICO. NATE WILL MOVE SLOWLY NORTH THROUGH FRI MORNING...THEN WILL TURN NW EARLY SAT MORNING AND BECOME STRONGER BEFORE IT TURNS WEST TOWARD MEXICO. STATIONARY FRONT WILL WEAKEN INTO A TROUGH OVER THE E GULF LATER TODAY. CARIBBEAN SEA... THE OUTER CONVECTION FROM TROPICAL STORM NATE IS GENERATING SHOWERS AND ISOLATED THUNDERSTORMS OVER THE EASTERN COAST OF THE YUCATAN PENINSULA AND IN THE GULF OF HONDURAS...SEE SPECIAL FEATURES SECTION ABOVE. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COSTA RICA TO NORTHERN COLOMBIA GENERATING SCATTERED SHOWERS AND THUNDERSTORMS S OF 12N W OF 75W. SIMILAR CONVECTION IS MOVING INTO THE NORTH CENTRAL BASIN N OF 15N BETWEEN 67W-81W ASSOCIATED TO A TROPICAL WAVE JUST E OF DOMINICAN REPUBLIC. DRY STABLE AIR ALOFT DOMINATES ELSEWHERE ACROSS THE DISCUSSION AREA WITH A FEW ISOLATED LOW TOP SHOWERS EMBEDDED IN THE EASTERLY TRADE WIND FLOW. MARIA IS FORECAST TO APPROACH THE LEEWARD/VIRGIN ISLANDS EARLY SATURDAY. THE TROPICAL WAVE OVER THE NE CARIBBEAN WILL MOVE ACROSS THE N CARIBBEAN TODAY BEFORE LIFTING N OVER THE BAHAMAS ON FRIDAY. ATLANTIC OCEAN... A NEARLY STATIONARY FRONT ENTERS THE DISCUSSION AREA OVER THE WEST ATLC NEAR 32N76W EXTENDING SW INTO CENTRAL FLORIDA ALONG CAPE CANAVERAL GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 70 NM EITHER SIDE OF THE FRONT. A TROPICAL WAVE IS ANALYZED JUST EAST OF DOMINICAN REPUBLIC GENERATING SIMILAR CONVECTION N OF PUERTO RICO FROM 19N-25N BETWEEN 60W-68W. AN UPPER TROUGH MOVES ACROSS THE N CENTRAL ATLC SUPPORTING A WEAK SURFACE EXTENDING FROM 32N32W ALONG 27N37W TO 25N423W GENERATING ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS WITHIN 35 NM ON EITHER SIDE OF THE AXIS. A WEAKENING BROAD SURFACE RIDGE DOMINATES ELSEWHERE ACROSS THE ATLC N OF 20N E OF 60W. HURRICANE KATIA IS N OF THE DISCUSSION AREA WITH TROPICAL STORM CONDITIONS CONTINUING N OF 29N FOR TODAY. SURFACE RIDGING WILL BUILD ACROSS THE AREA IN THE WAKE OF KATIA TODAY THROUGH SAT. TROPICAL STORM MARIA WILL MOVE NEAR THE NRN LESSER ANTILLES BETWEEN SATURDAY AND SUNDAY BEFORE MOVING E OF THE BAHAMAS DURING THE FIRST OF THE WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA