** WTNT45 KNHC 010833 *** TCDAT5 TROPICAL STORM ZETA DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 4 AM EST SUN JAN 01 2006 THE BURST OF DEEP CONVECTION THAT OCCURRED EARLIER HAS BEEN ON THE WANE SOMEWHAT DURING THE PAST FEW HOURS. HOWEVER... SHEAR PATTERN SATELLITE INTENSITY ESTIMATES REMAIN AT ABOUT 45 KT... AND THAT IS THE INTENSITY USED FOR THIS ADVISORY. UPPER-LEVEL OUTFLOW REMAINS CONFINED MAINLY TO THE NORTHEASTERN QUADRANT... ALTHOUGH THE CIRRUS OUTFLOW OVER THE LOW-LEVEL CENTER HAS EXPANDED SOMEWHAT TO THE SOUTHWEST... WHICH HAS MADE LOCATING THE CENTER A LITTLE DIFFICULT. THE MOTION ESTIMATE IS 270/02 KT... BASED ON AN 18-HR MOTION. ZETA IS EXPECTED TO MOVE SLOWLY WEST OR EVEN WEST-SOUTHWESTWARD AROUND THE SOUTHWESTERN PERIPHERY OF A LOW- TO MID-LEVEL HIGH PRESSURE RIDGE LOCATED EAST-WEST OVER THE AZORES ISLANDS. THE MID- TO UPPER-LEVEL FLOW...HOWEVER...IS FORECAST TO REMAIN FROM A GENERAL WESTERLY DIRECTION...SO THE OFFSETTING FLOW PATTERNS SHOULD RESULT IN A SLOW FORWARD SPEED THROUGHOUT THE FORECAST PERIOD. THE GLOBAL MODELS ARE IN GENERAL AGREEMENT ON THIS MOTION... WHEREAS THE GFDN AND GFDL MODELS APPEAR TO BE OUTLIERS BY TAKING ZETA NORTHWARD ALONG 44W-46W LONGITUDE AFTER 72 HOURS AS A VERTICALLY DEEP HURRICANE... WHICH SEEMS UNLIKELY. THE OFFICIAL FORECAST TRACK IS CLOSE TO THE PREVIOUS TRACK AND THE GLOBAL MODEL CONSENSUS. ZETA REMAINS CAUGHT IN A SOMEWHAT FAVORABLE DIFLUENT FLOW REGION BETWEEN THE SUBTROPICAL JET TO THE SOUTH AND THE POLAR JET TO THE NORTH. HOWEVER... SHEAR ANALYSES FROM UW-CIMSS INDICATE 25-30 KT OF VERTICAL SHEAR... WHICH IS ABOUT 20-25 KT LESS THAN THE SHIPS MODEL SHEAR ASSESSMENT... IS STILL IMPINGING ON ZETA. THAT MAGNITUDE OF SHEAR IS FORECAST TO CONTINUE FOR THE NEXT 24 HOURS OR SO... WITH A SLIGHT DECREASE IN SHEAR EXPECTED IN THE 24-48 HOUR TIME PERIOD. HOWEVER... WITH ZETA MOVING INTO A DRIER ENVIRONMENT THROUGHOUT THE FORECAST PERIOD... ANY DECREASE IN THE VERTICAL SHEAR SHOULD BE OFFSET BY THE VERY DRY MID-LEVEL AIR. THE RESULT IS THAT GRADUAL WEAKENING IS EXPECTED... BUT NOT QUITE AS FAST AS THE SHIPS MODEL WHICH IS FORECASTING ZETA TO DISSIPATE IN 36-48 HOURS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 01/0900Z 25.7N 38.5W 45 KT 12HR VT 01/1800Z 25.6N 39.2W 40 KT 24HR VT 02/0600Z 25.5N 40.2W 35 KT 36HR VT 02/1800Z 25.5N 41.2W 30 KT 48HR VT 03/0600Z 25.8N 42.2W 25 KT...REMNANT LOW 72HR VT 04/0600Z...DISSIPATED $$ ** WTNT75 KNHC 010834 *** SPFAT5 TROPICAL STORM ZETA PROBABILITIES NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM AST SUN JAN 01 2006 PROBABILITIES FOR GUIDANCE IN HURRICANE PROTECTION PLANNING BY GOVERNMENT AND DISASTER OFFICIALS AT 5 AM AST...0900Z...THE CENTER OF ZETA WAS LOCATED NEAR LATITUDE 25.7 NORTH...LONGITUDE 38.5 WEST CHANCES OF CENTER OF THE STORM PASSING WITHIN 65 NAUTICAL MILES OF LISTED LOCATIONS THROUGH 2AM AST WED JAN 4 2006 LOCATION A B C D E LOCATION A B C D E 25.5N 40.2W 57 X X X 57 25.8N 42.2W 30 3 1 X 34 25.5N 41.2W 41 X X X 41 COLUMN DEFINITION PROBABILITIES IN PERCENT A IS PROBABILITY FROM NOW TO 2AM MON FOLLOWING ARE ADDITIONAL PROBABILITIES B FROM 2AM MON TO 2PM MON C FROM 2PM MON TO 2AM TUE D FROM 2AM TUE TO 2AM WED E IS TOTAL PROBABILITY FROM NOW TO 2AM WED X MEANS LESS THAN ONE PERCENT FORECASTER STEWART $$ ** WTNT25 KNHC 010834 *** TCMAT5 TROPICAL STORM ZETA FORECAST/ADVISORY NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL302005 0900Z SUN JAN 01 2006 TROPICAL STORM CENTER LOCATED NEAR 25.7N 38.5W AT 01/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 2 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT.......120NE 100SE 30SW 75NW. 12 FT SEAS..200NE 200SE 120SW 200NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 25.7N 38.5W AT 01/0900Z AT 01/0600Z CENTER WAS LOCATED NEAR 25.7N 38.4W FORECAST VALID 01/1800Z 25.6N 39.2W MAX WIND 40 KT...GUSTS 50 KT. 34 KT...100NE 100SE 20SW 70NW. FORECAST VALID 02/0600Z 25.5N 40.2W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 70NE 70SE 0SW 50NW. FORECAST VALID 02/1800Z 25.5N 41.2W MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 03/0600Z 25.8N 42.2W...REMNANT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 04/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.7N 38.5W NEXT ADVISORY AT 01/1500Z FORECASTER STEWART $$ ** WTNT35 KNHC 010839 *** TCPAT5 BULLETIN TROPICAL STORM ZETA ADVISORY NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM AST SUN JAN 01 2006 ...ZETA CONTINUING TO DRIFT SLOWLY WESTWARD OVER THE FAR EASTERN ATLANTIC OCEAN... ...ONLY A THREAT TO SHIPPING INTERESTS... AT 5 AM AST...0900Z...THE CENTER OF TROPICAL STORM ZETA WAS LOCATED NEAR LATITUDE 25.7 NORTH... LONGITUDE 38.5 WEST OR ABOUT 1085 MILES...1745 KM... SOUTHWEST OF THE AZORES. ZETA IS DRIFTING TOWARD THE WEST NEAR 2 MPH... 4 KM/HR...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS. MAXIMUM SUSTAINED WINDS ARE NEAR 50 MPH... 85 KM/HR...WITH HIGHER GUSTS. SOME WEAKENING IS POSSIBLE DURING THE NEXT 24 HOURS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140 MILES ...220 KM...MAINLY NORTH AND NORTHEAST OF THE CENTER. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB...29.53 INCHES. REPEATING THE 5 AM AST POSITION...25.7 N... 38.5 W. MOVEMENT TOWARD...WEST NEAR 2 MPH. MAXIMUM SUSTAINED WINDS... 50 MPH. MINIMUM CENTRAL PRESSURE...1000 MB. THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT 11 AM AST. FORECASTER STEWART $$