Tropical storm Bill

[Matt-hurricanewatcher]

Wave moved into the Yucatan then the next day reformed a low to the northwest of it. Recon found us a cyclone!

[Sciencerocks]

000
WONT41 KNHC 291301
DSAAT
SPECIAL TROPICAL DISTURBANCE STATEMENT
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
9 AM EDT SUN JUN 29 2003

VISIBLE SATELLITE PICTURES THIS MORNING SHOW THAT THE AREA OF
DISTURBED WEATHER IN THE SOUTH CENTRAL GULF OF MEXICO HAS ACQUIRED
A WEAK LOW LEVEL CIRCULATION. ALSO A RECENT SHIP REPORT INDICATES
THAT WINDS ARE ALREADY NEAR 40 MPH. THE NATIONAL HURRICANE CENTER
WILL ISSUE ITS FIRST ADVISORY ON THIS DEVELOPING TROPICAL STORM AT
11 AM EDT.

FORECASTER LAWRENCE



CZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT SUN JUN 29 2003

VISIBLE SATELLITE IMAGES SHOW THAT A LOW CLOUD CIRCULATION CENTER
HAS FORMED OVERNIGHT TO GO ALONG WITH THE DEEP CONVECTION THAT HAS
PERSISTED FOR A SEVERAL DAYS. THE SHIP H3GQ REPORTED 38 KNOTS IN
THE DEEP CONVECTION AT 12Z. THE SHIP IS LOCATED ABOUT 150 N MI
NORTHEAST OF THE CENTER. WITH THE CONVECTION AND STRONGEST WINDS
LOCATED RATHER FAR FROM THE CENTER...THIS CYCLONE MIGHT BE
CLASSIFIED AS SUBTROPICAL...BUT SINCE THE ORIGINS OF THE WEATHER
WERE TROPICAL...A TROPICAL DESIGNATION IS USED.

THE INITIAL MOTION ESTIMATE IS 320/14 ALTHOUGH THIS IS HIGHLY
UNCERTAIN SINCE THERE IS NO GOOD HISTORY TO THE LOW LEVEL CENTER.
THE GUIDANCE IS IN GOOD AGREEMENT ON A TRACK TURNING NORTHWARD
AROUND THE WESTERN PERIPHERY OF A MID LEVEL HIGH PRESSURE RIDGE
THAT EXTENDS EASTWARD FROM THE EASTERN GULF OF MEXICO. THE
GUIDANCE IS ALSO IN GOOD AGREEMENT ABOUT A SLOWER FORWARD SPEED
THAT THE 14 KNOTS USED FOR THE INITIAL MOTION AND THE FORECAST
TRACK FOLLOWS THIS.

THE OFFICIAL WIND SPEED IS 35 KNOTS BASED ON THE SHIP REPORT
MENTIONED ABOVE. WITH WEAK VERTICAL SHEAR AND WARM SSTS...THE
SHIPS MODEL BRINGS THE WIND SPEED TO 55 KNOTS IN 48 HOURS. THE
OFFICIAL FORECAST BACKS OFF A LITTLE TO 50 KNOTS SINCE NONE OF THE
GLOBAL MODELS SHOW ANY STRENGTHENING BEFORE LANDFALL.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL 29/1500Z 23.5N 91.5W 35 KT
12HR VT 30/0000Z 24.9N 92.8W 40 KT
24HR VT 30/1200Z 26.8N 93.8W 45 KT
36HR VT 01/0000Z 28.7N 94.2W 50 KT
48HR VT 01/1200Z 30.2N 94.2W 30 KT...INLAND
72HR VT 02/1200Z 31.3N 93.3W 25 KT...INLAND
96HR VT 03/1200Z 32.3N 90.8W 20 KT...INLAND
120HR VT 04/1200Z...DISSIPATED INLAND


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ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SUN JUN 29 2003

REPORTS FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT THIS
AFTERNOON INDICATE THAT LOW LEVEL CIRCULATION CENTER IS NOT VERY
WELL DEFINED. THIS MAKES THE INITIAL MOTION RATHER UNCERTAIN. THE
INITIAL MOTION ESTIMATE IS 335/11. THE TRACK GUIDANCE IS IN GOOD
AGREEMENT ABOUT TURNING THE STORM NORTH AND THEN EASTWARD AROUND
THE WESTERN PERIPHERY OF A MID LEVEL HIGH PRESSURE RIDGE EXTENDING
EASTWARD FROM THE EASTERN GULF OF MEXICO. HOWEVER THE GUIDANCE
ALSO SHIFTS THE TRACKS EASTWARD ABOUT 100 N MI FROM THE PREVIOUS
ADVISORY AND SO DOES THE OFFICIAL FORECAST. THIS IS PARTIALLY DUE
TO SHIFTING THE INITIAL POSITION EASTWARD. THIS ALSO REQUIRES AN
EASTWARD SHIFT TO THE WATCH AREA WHICH WILL ALSO BE CHANGED TO A
WARNING.

THE AIRCRAFT MEASURED A CENTRAL PRESSURE OF 1010 MB...NOT VERY
LOW...BUT THE PRESSURE GRADIENT TO THE EAST OF THE STORM IS LARGE.
A 15Z SHIP REPORT OF 40 KNOTS ABOUT 80 N MI NORTHEAST OF THE CENTER
...ALONG WITH AIRCRAFT OBSERVATIONS...IS THE BASIS FOR INCREASING
THE WIND SPEED TO 40 KNOTS. THE SHIPS MODEL BRINGS THE WIND TO 62
KNOTS IN 24 HOURS UNDER LIGHT SHEAR AND WARM SSTS. IN CONTRAST
NONE OF THE GLOBAL MODELS SHOW STRENGTHENING. ALSO THE PRESENT
DEEP CONVECTION PATTERN IS NOT VERY IMPRESSIVE. THE OFFICIAL
FORECAST IS A COMPROMISE 55 KNOTS AT 24 HOURS.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL 29/2100Z 24.8N 91.1W 40 KT
12HR VT 30/0600Z 26.4N 91.9W 45 KT
24HR VT 30/1800Z 28.5N 92.5W 55 KT
36HR VT 01/0600Z 30.5N 92.0W 30 KT...INLAND
48HR VT 01/1800Z 31.5N 90.5W 20 KT...INLAND
72HR VT 02/1800Z 33.0N 86.0W 20 KT...INLAND
96HR VT 03/1800Z...INLAND




TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SUN JUN 29 2003

AIR FORCE RESERVE RECON FIXES EARLIER THIS AFTERNOON INDICATED THAT
THE CENTER OF BILL HAD MOVED NORTHWARD AND CLOSER TO THE DEEP
CONVECTION. HOWEVER...THE CENTER OF BILL IS NOT EMBEDDED WITHIN THE
CDO-LOOKING FEATURE. INSTEAD...SATELLITE ESTIMATES SUGGEST THE
LOW-LEVEL CENTER IS LOCATED ALONG THE SOUTHWEST EDGE OF THE COLD
CLOUD CANOPY. THIS ALSO YIELDS A SHEAR PATTERN INTENSITY ESTIMATE
OF ABOUT 45 KT...WHICH IS CLOSE TO THE LAST RECON REPORTED SURFACE
WIND ADJUSTMENT OF 43 KT. THERE IS STILL SOME SOUTHEASTERLY
UPPER-LEVEL SHEAR IMPINGING ON THE CYCLONE...BUT THE OVERALL
OUTFLOW PATTERN HAS IMPROVED DURING THE PAST 6 HOURS.

THE INITIAL MOTION ESTIMATE IS 350/12. WHILE RECON FIXES SUGGEST A
NORTH TO SLIGHTLY EAST OF DUE NORTH TRACK...MY FEELING IS THAT THIS
MOTION HAS BEEN DUE PRIMARILY AS A RESAULT OF DEVELOPMENT OF THE
CENTER CLOSER TO THE DEEP CONVECTION...RATHER THAN AN ACTUAL
TRANSLATIONAL MOTION. LATEST UPPER-AIR DATA INDICATE THE MID- TO
UPPER-LEVEL RIDGE AXIS PREVIOUSLY ALONG THE GULF COAST HAS MIGRATED
NORTHWARD TO ABOUT 30N LATITUDE WITH MODERATE WESTERLY FLOW ACROSS
THE MISSOURI AND TENNESSEE VALLEYS AHEAD OF A WEAK SHORTWAVE TROUGH
CURRENTLY LOCATED OVER THE CENTRAL PLAINS. MOST OF THE GLOBAL
MODELS MAINTAIN THE CURRENT RIDGE-TROUGH PATTERN AND THERE IS A
FAIRLY TIGHT CLUSTERING OF THE NHC MODEL GUIDANCE SUITE UNTIL
LANDFALL. AFTER THAT...THE MODELS DIVERGE SIGNIFICANTLY WITH THE
GFDL TAKING BILL INTO WESTERN KENTUCKY IN 72 HOURS WHILE THE UKMET
HAS BILL IN CENTRAL SOUTH CAROLINA AT THE SAME TIME. THE OFFICIAL
FORECAST TRACK WAS ADJUSTED SLIGHTLY EAST OF THE PREVIOUS FORECAST
DUE TO THE MORE EASTWARD LOCATION OF THE INITIAL POSITION.
HOWEVER...THERE IS GOOD AGREEMENT BY THE MODELS ON LANDFALL
OCCURRING SOMEWHERE ALONG THE SOUTH CENTRAL LOUISIANA COAST BY LATE
MONDAY.

THE INTENSITY FORECAST IS A LITTLE MORE PROBLEMATIC. THE UPPER-LEVEL
FLOW PATTERN IS FORECAST TO REMAIN STRONGLY DIFLUENT UNTIL JUST
PRIOR TO LANDFALL. WATER TEMPERATURES CURRENTLY BENEATH BILL ARE
AROUND 83F/28C AND ARE AROUND 86F/30C ALONG AND JUST OFFSHORE THE
LOUISIANA COAST. WITH WARMER WATER AHEAD AND SLIGHTLY DECREASING
VERTICAL SHEAR EXPECTED...IT IS POSSIBLE THAT BILL COULD STRENGTHEN
INTO A CATEGORY 1 HURRICANE JUST BEFORE MAKING LANDFALL. THE SHIPS
INTENSITY MODEL BRINGS BILL UP TO 62 KT...JUST BELOW HURRICANE
STRENGTH...IN 24 HOURS. FOR THIS REASON...A HURRICANE WATCH HAS
BEEN ISSUED FOR A SMALL PORTION OF THE SOUTH CENTRAL LOUISIANA
COAST. IF THE LOW-LEVEL CENTER TUCKS IN UNDER THE COLD CLOUD TOPS
LATER TONIGHT...THEN A STRONGER CYCLONE THAN FORECAST WOULD RESULT.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/0300Z 26.3N 91.3W 45 KT
12HR VT 30/1200Z 27.6N 91.6W 50 KT
24HR VT 01/0000Z 29.6N 91.9W 60 KT
36HR VT 01/1200Z 31.9N 91.0W 30 KT...INLAND
48HR VT 02/0000Z 33.3N 88.5W 20 KT...INLAND REMNANT LOW
72HR VT 03/0000Z 35.0N 83.0W 20 KT...INLAND REMNANT LOW
96HR VT 04/0000Z 36.0N 75.5W 25 KT...REMNANT LOW



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[Sciencerocks]

ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT MON JUN 30 2003

THERE HAS NOT BEEN A SIGNIFICANT CHANGE IN THE CLOUD PATTERN
ASSOCIATED WITH BILL. THE LOW-LEVEL CENTER IS NOT CLEARLY OBSERVED
BUT IT APPEARS TO BE LOCATED TO THE SOUTH OR SOUTHWEST OF THE MAIN
AREA OF CONVECTION. INITIAL INTENSITY REMAINS AT 45 KNOTS. BECAUSE
THE SHEAR IS FORECAST TO RELAX AND THE OCEAN IS WARM...THERE IS
SMALL WINDOW OF OPPORTUNITY FOR BILL TO BECOME A MINIMAL HURRICANE
BEFORE LANDFALL. A NEW RECON WILL BE IN THE AREA AROUND 12 UTC.

BILL IS MOVING TOWARD THE NORTH OR 350 DEGREES AT 12 KNOTS. THE
CYCLONE IS MOVING AROUND THE WESTERN PERIPHERY OF A MID-LEVEL RIDGE
THAT EXTENDS FROM THE ATLANTIC WESTWARD ACROSS FLORIDA...AND NO
SIGNIFICANT CHANGE IN MOTION IS EXPECTED BEFORE LANDFALL LATER
TODAY. TRACK GUIDANCE UNANIMOUSLY BRINGS BILL NORTHWARD TO NEAR THE
COAST IN ABOUT 12 HOURS. THEREAFTER...BILL OR ITS REMNANTS SHOULD
TURN MORE TO THE NORTHEAST AS IT BECOMES EMBEDDED WITHIN THE
SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING SHORT WAVE TROUGH.

ONE SHOULD NOT FOCUS ON THE CENTER OR THE EXACT TRACK OF THE
TROPICAL CYCLONE SINCE STRONG WINDS AND HEAVY RAINS CAN BE
EXPERIENCED WELL AWAY FROM THE CENTER.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/0900Z 27.6N 91.6W 45 KT
12HR VT 30/1800Z 29.2N 91.7W 60 KT
24HR VT 01/0600Z 32.0N 91.0W 25 KT...INLAND
36HR VT 01/1800Z 34.0N 89.0W 20 KT...REMNANT LOW
48HR VT 02/0600Z 35.0N 86.0W 20 KT...REMNANT LOW
72HR VT 03/0600Z 36.0N 80.0W 20 KT...REMNANT LOW
96HR VT 04/0600Z 37.0N 72.0W 20 KT...REMNANT LOW





ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT MON JUN 30 2003

THE INITIAL MOTION ESTIMATE IS 360/12. THIS MOTION IS EXPECTED TO
BRING THE CENTER ACROSS THE COAST AND INTO SOUTH-CENTRAL LOUISIANA
IN 12 HOURS. THEREAFTER THE GUIDANCE IS IN CLOSE AGREEMENT ABOUT
TURNING THE REMNANT LOW OVER LAND TOWARD THE EAST AS THE STORM
ENCOUNTERS THE WESTERLIES. THEREFORE THE FORECAST TRACK IS SIMILAR
TO THE PREVIOUS ADVISORY.

A RECENT RECON AIRCRAFT REPORTED THAT THE CENTRAL PRESSURE HAS
FALLEN TO 1001 MB. THE MAXIMUM SURFACE WIND SPEED IS INCREASED TO
50 KNOTS BASED ON A FLIGHT LEVEL WIND OF 66 KNOTS SOUTHEAST OF THE
CENTER. HOWEVER...THE WIND SPEED CAN STILL INCREASE DURING THE
SEVERAL HOURS REMAINING BEFORE LANDFALL.

DO NOT FOCUS ON THE EXACT LOCATION OF THE CENTER OR THE FORECAST
TRACK OF THE TROPICAL CYCLONE SINCE STRONG WINDS AND HEAVY RAINS
CAN BE EXPERIENCED WELL AWAY FROM THE CENTER.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/1500Z 28.8N 91.5W 50 KT
12HR VT 01/0000Z 30.5N 91.5W 40 KT...INLAND
24HR VT 01/1200Z 32.7N 90.5W 30 KT...INLAND
36HR VT 02/0000Z 34.6N 88.7W 20 KT...INLAND
48HR VT 02/1200Z 36.0N 86.0W 20 KT...INLAND
72HR VT 03/1200Z 36.5N 80.5W 20 KT...INLAND
96HR VT 04/1200Z...INLAND


NNNN

[Sciencerocks]

L
TTAA00 KNHC DDHHMM
TROPICAL STORM BILL DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT MON JUN 30 2003

THE MOTION HAS BEEN ERRATIC TOWARD THE NORTHEAST FOR THE PAST FEW
HOURS. THIS IS BELIEVED TO BE A TEMPORARY WOBBLE AS THE CENTER
LOOKED RATHER COMPLEX AS VIEWED BY RADAR AND SATELLITE. A 020/9
MOTION IS EXPECTED TO RESUME SHORTLY. THE GUIDANCE REMAINS IN
AGREEMENT ABOUT A TURN TOWARD THE EAST OVER THE NEXT SEVERAL DAYS
AS THE STORM ENCOUNTERS THE WESTERLIES. THE GFS MODEL SHOWS BILL
DISSIPATING OVER TENNESSEE BY 96 HOURS WHILE SOME OF THE OTHER
GUIDANCE BRING THE LOW OVER THE ATLANTIC. THE OFFICIAL FORECAST
FOLLOWS A CONCENSUS OF THE GUIDANCE BUT DISSIPATES BILL AFTER 72
HOURS.

THE CENTER IS AT THE COAST. SURFACE OBSERVATIONS FROM TERREBONE BAY
INCLUDE A 997 MB PRESSURE AND SUSTAINED WIND SPEEDS NEAR 50 KNOTS.
WINDS OVER THE WATER WILL LIKELY REMAIN ABOVE 35 KNOTS FOR SEVERAL
MORE HOURS...WHILE WINDS NEAR THE CENTER ARE EXPECTED TO WEAKEN AS
THE STORM MOVES FURTHER INLAND.

ASIDE FROM WINDS AND SURGE AT THE COAST...HEAVY RAIN WILL BE A
SERIOUS THREAT FOR PORTIONS OF LOUISIANA...MISSISSIPPI...ALABAMA...
AND THE FLORIDA PANHANDLE.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/2100Z 29.5N 90.8W 50 KT
12HR VT 01/0600Z 30.8N 90.4W 40 KT...INLAND
24HR VT 01/1800Z 32.9N 89.1W 30 KT...INLAND
36HR VT 02/0600Z 34.8N 86.8W 25 KT...INLAND
48HR VT 02/1800Z 36.0N 84.4W 20 KT...INLAND
72HR VT 03/1800Z 37.5N 79.0W 20 KT...INLAND
96HR VT 04/1800Z...INLAND







TROPICAL STORM BILL DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT MON JUN 30 2003

BILL STILL LOOKS FAIRLY IMPRESSIVE IN BOTH SATELLITE AND RADAR
IMAGERY. IN FACT...THE OUTFLOW PATTERN IS THE BEST IT HAS LOOKED
DURING THE RELATIVELY SHORT LIFETIME OF THIS CYCLONE. THE INITIAL
INTENSITY OF 40 KT IS BASED ON A 35 KT SUSTAINED WIND REPORT AT
KGPT AND DOPPLER VELOCITIES OF 50 TO 60 KT JUST A FEW HUNDRED FEET
ABOVE THE SURFACE AS NOTED N THE SLIDELL/KLIX RADAR IMAGERY.

THE INITIAL MOTION ESTIMATE IS 020/09. BILL HAS BEEN TRACKING
STEADILY NORTH-NORTHEASTWARD THE PAST FEW HOURS AT A MUCH SLOWER
SPEED THAN IT WAS EARLIER THIS AFTERNOON. THERE IS GOOD CONVERGENCE
AMONG THE VARIOUS NHC FORECAST MODELS CONCERNING THE TRACK
DIRECTION. HOWEVER...THE FORECAST TRACK SPEEDS VARY SIGNIFICANTLY
WITH THE UKMET AND CANADIAN MODELS BEING THE FASTEST. BOTH OF THOSE
MODELS MAINTAIN A SIGNIFICANT LOW PRESSURE SYSTEM THROUGHOUT THE
PERIOD AND HAVE THE REMNANTS OF BILL NEAR THE DELMARVA AND SOUTHERN
NEW JERSEY COASTS IN 72 HOURS. HOWEVER...IN 36 TO 48 HOURS BILL IS
EXPECTED TO GRADUALLY LINK UP WITH A SLOW MOVING SHORTWAVE TROUGH
CURRENTLY LOCATED OVER THE CENTRAL PLAINS. THE OFFICIAL FORECAST IS
MUCH SLOWER AND CLOSE TO THE PREVIOUS FORECAST TRACK...AND IS
SIMILAR TO THE GFS...GFS ENSEMBLE...AND GFDL MODEL SOLUTIONS.

NOW THAT BILL IS WELL INLAND STEADY WEAKENING IS FORECAST AND BILL
SHOULD WEAKEN TO A TROPICAL DEPRESSION DURING THE NEXT 12
HOURS...AND SOME WIND GUSTS TO TROPICAL STORM FORCE ARE EVEN
POSSIBLE AS FAR EAST AS MOBILE BAY FOR ANOTHER FEW HOURS. WHILE
BILL MAY BE LOSING ITS TROPICAL CHARACTERISTICS...THE CYCLONE IS
GRADUALLY ACQUIRING A GREATER POTENTIAL TO PRODUCE SIGNIFICANT
TORNADIC ACTIVITY...ESPECIALLY DURING THE DAY TUESDAY WHEN
AFTERNOON HEATING WILL HELP TO MAKE THE ATMOSPHERE MORE UNSTABLE.
IN ADDITION...COASTAL STORM SURGE FLOODING WILL REMAIN A PROBLEM
TONIGHT ALONG WITH LOCALLY HEAVY RAINFALL AND POSSIBLY INLAND FRESH
FLOODING.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 01/0300Z 30.8N 90.1W 40 KT
12HR VT 01/1200Z 32.5N 89.3W 30 KT...DISSIPATING INLAND
24HR VT 02/0000Z 34.3N 87.5W 25 KT...DISSIPATING INLAND
36HR VT 02/1200Z 35.7N 85.1W 20 KT...INLAND REMNANT LOW
48HR VT 03/0000Z 36.8N 82.2W 20 KT...INLAND REMNANT LOW
72HR VT 04/0000Z 37.5N 78.0W 20 KT...INLAND REMNANT LOW
96HR VT 05/0000Z...DISSIPATED