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Q: Hurricane Juan vs Tropical Storm Juan ( Answered 5 out of 5 stars,   2 Comments )
Question  
Subject: Hurricane Juan vs Tropical Storm Juan
Category: Reference, Education and News > Current Events
Asked by: brudenell-ga
List Price: $5.00
Posted: 01 Oct 2003 16:55 PDT
Expires: 31 Oct 2003 15:55 PST
Question ID: 262017
At approximately what time (AST) and geographical location did
Hurricane Juan become downgraded to Tropical Storm Juan on the night
of September 28 - 29, 2003? Please be as precise as possible. Thank
you for your interest in this question.
Answer  
Subject: Re: Hurricane Juan vs Tropical Storm Juan
Answered By: mvguy-ga on 01 Oct 2003 20:33 PDT
Rated:5 out of 5 stars
 
The best information I could find indicates that the storm was
downgraded around midnight of Sept. 28-29 near Halifax, as the
following news articles indicate:

Canada.com
"Severity: A Category 1 hurricane, the weakest rating on the
Saffir-Simpson scale. Was downgraded to a tropical storm shortly after
hitting land.
"Peak gust: 143 kilometres per hour.
"Where: The hurricane made landfall at Sambro, N.S., and passed
directly over Halifax before moving north across the province and over
Prince Edward Island.
"When: The hurricane's effects were first felt in Halifax at about 11
a.m. Sunday and it reached its peak at about 1 a.m., yesterday."
http://canada.com/national/story.asp?id=A9B4DBB3-75FB-4672-A854-31847B597273

CP Atlantic Regional News
"The category 1 hurricane - the weakest rating on the Saffir-Simpson
scale - was downgraded to a tropical storm shortly after making
landfall in the Halifax area."
http://canadaeast.com/apps/pbcs.dll/article?AID=/20030930/CPA/4622014&cachetime=15

Associated Press
"Hurricane Juan lashed Nova Scotia with 86 mph winds Sunday, ripping
off roofs, uprooting trees, knocking out power and killing at least
three people before weakening to a tropical storm and heading north to
Prince Edward Island.
"Late Monday, Juan weakened to a tropical depression and was headed
out to sea, where it was expected to dissipate."
http://www.kansascity.com/mld/kansascity/news/breaking_news/6892392.htm

MIT
"The center of Juan passed over the southern coast of Nova Scotia west
of Halifax Sunday night, with the highest reported winds being 62 mph.
The Category 1 hurricane (the weakest possible) was downgraded to a
tropical storm shortly after making landfall in the Halifax area
around midnight. Juan drenched Prince Edward Island, uprooting trees
and cutting power lines."
http://www-tech.mit.edu/V123/N44/weather_44.44w.html

Finally, data from StormTrack indicates that the storm was downgraded
between 11 p.m. on Sunday and 5 a.m. on Monday (which would make it
near Hallifax), as indicated on the following page:
http://weather.terrapin.com/wx/storm_show.jsp?area=ATL&storm=15A&dtype=ASCII

That timing coincides with the following reports at 11 p.m. and 5 a.m.
respectively:

Sep 28 2003 11:00PM EDT
"AT 11 PM AST...0300Z...THE CENTER OF HURRICANE JUAN WAS LOCATED NEAR
LATITUDE 44.5 NORTH...LONGITUDE 63.8 WEST. THIS POSITION IS ON 
THE COAST OF NOVA SCOTIA AND ABOUT 30 MILES...50 KM...SOUTHWEST OF 
HALIFAX."
http://hurricane.terrapin.com/text/1064818461-HAPT35US.TXT.html.en

Sep 29 2003 5:00AM EDT
"AT 5 AM AST...0900Z...THE CENTER OF TROPICAL STORM JUAN WAS 
LOCATED NEAR LATITUDE 47.8 NORTH...LONGITUDE 63.4 WEST OR ABOUT 
50 MILES...80 KM...NORTH-NORTHEAST OF NORTH POINT ON PRINCE EDWARD 
ISLAND."
http://hurricane.terrapin.com/text/1064838386-HAPT35US.TXT.html.en

I did come across one article that indicated the downgrading took
place later on Monday:

Portsmouth Herald
"State climatologist Jason Allard of the University of New Hampshire
said the hurricane was downgraded to a tropical storm as it passed
through Newfoundland Monday [Sept. 29] afternoon."
http://www.seacoastonline.com/news/09302003/news/52726.htm

I would assume that the Portsmouth article was in error, that it
actually was downgraded from a tropical storm to a tropical depression
at that time.

These articles provided the most complete information I was able to
find about time and place. I hope the data is precise enough for your
needs.

Sincerely,

Mvguy-ga




Search strategy:

Google News search term: "hurricane juan" downgraded
http://news.google.com/news?hl=en&ie=ISO-8859-1&edition=us&q=%22hurricane+juan%22+downgraded

Google search term: hurricane watch
://www.google.com/search?q=hurricane+watch

Request for Answer Clarification by brudenell-ga on 02 Oct 2003 05:27 PDT
Hello mvguy-ga

According to: http://www.ns.ec.gc.ca/weather/hurricane/hurricanes9.html#hurricane

"Hurricanes are cyclones of tropical origin with wind speeds of at
least 118 kilometres per hour."

The Charlottetown, Prince Edward Island newspaper - The Guardian
reported that wind gusts peaked at 3:17am at the airport with gusts
clocked at 146 km/ hr:

http://www.theguardian.pe.ca/MainPage.aspx?PageType=FullStory&PartialStory=No&StoryID=3804

Can we conclude that the hurricane was in the Charlottetown area (46
14' 25" N - 63 08' 05" W) and thus became a tropical storm somewhere
between the city and the location given in the 5 am report "LATITUDE
47.8 NORTH...LONGITUDE 63.4 WEST"?

Brudenell

Clarification of Answer by mvguy-ga on 02 Oct 2003 06:30 PDT
Probably not. What you're talking about is wind GUSTS, which are
higher (sometimes much higher) than the SUSTAINED wind speeds.  But if
you look at the definitions of "tropical storm" and "hurricane watch,"
you can see that what we're talking about in defining terms is
sustained wind speeds. All the reports indicate that the wind speeds
slowed down quickly upon landfall, so it would appear, based on the
reports, that by the storm was that far north it was no longer
technically a hurricane.

Note that the AP story says specifically that the hurricane became a
tropical storm before heading north to Prince Edward Island (where
Charlottesville is). Also, the hurricane was the lowest category of
hurricane before it arrived at Halifax, so it wouldn't have had to
slow down much to become a tropical storm.  Also, the 11 p.m. weather
report said by then that sustained winds had already dropped to 130
kph and that they would quickly fall.  That weather report coincides
with the news reports that indicate the storm was no longer a
hurricane by the time it left the Halifax area. But it was still a
pretty powerful storm!

Best wishes,

Mvguy-ga

Request for Answer Clarification by brudenell-ga on 04 Oct 2003 03:10 PDT
Hello mvguy-ga

Thanks for your clarification response. Your information is
corroborated by this information from the Canadian Hurricane Centre on
the Environment Canada site:

Hurricane Juan Summary (excerpts)

Prepared by Peter Bowyer
Program Manager, Canadian Hurricane Centre 

At 12:10 a.m. ADT, Monday September 29, 2003, Hurricane Juan made
landfall in Nova Scotia between Shad Bay and Prospect. Juan arrived as
a strong Category 1 storm with some data indicating that it may be
subsequently classified as a Category 2. The storm ripped northward
through the province, weakening quickly as tropical cyclones do over
land, arriving in Prince Edward Island as a tropical storm, but with
winds still gusting to hurricane force.

The storm tracked almost due north, crossing the Northumberland Strait
around 3 a.m. ADT (near or over the eastern portion of the
Confederation Bridge) and crossed Prince Edward Island (landfall close
to or east of Borden) in less than an hour.

The highest sustained winds (2-minute mean) recorded by a land station
were 151 km/h at McNab's Island, in Halifax Harbour, with gusts to 176
km/h at 12:24 a.m. ADT (communication failure at the McNab's site
prevented weather office from seeing this data until later).

The maximum wind core (eastern eyewall) went right over Halifax
Harbour.

Juan was below hurricane strength (determined by sustained winds, not
gusts) when it reached P.E.I., with Charlottetown airport reporting a
sustained wind of 95 km/h and gusts to 139 km/h at 3:17 a.m. ADT.

Clarification of Answer by mvguy-ga on 04 Oct 2003 07:05 PDT
Thanks for the generous rating and the tip. I was glad to be of help
and enjoyed learning more about hurricanes in the process.
brudenell-ga rated this answer:5 out of 5 stars and gave an additional tip of: $2.00
Thanks for providing an informative answer.

Comments  
Subject: Re: Hurricane Juan vs Tropical Storm Juan
From: tutuzdad-ga on 01 Oct 2003 19:38 PDT
 
Dear brudenell-ga;

Sometimes when researchers can’t pinpoint an exact answer but feel
they’ve found as an answer as close as possible to the exact answer,
we post it as a comment to see if it flies. Since I cannot give you an
actual time or a location that’s is exactly what I am doing. I am
posting this as a comment for the time being.

As near as can be determined, we must rely on official reports to
determine at what point Hurricane Juan was first downgraded to a
Tropical Storm. Naturally the exact moment that the magnitude of the
storm “actually” regressed from a hurricane to that of a tropical
storm was somewhat before the official announcement, but probably not
long.

In these official bulletins, the first of which is time stamped 5 PM
AST SUN SEP 28 2003, the National Weather Service National Hurricane
and Tropical Prediction Center described the position of Hurricane
Juan in this manner:

“THE CENTER OF HURRICANE JUAN WAS LOCATED NEAR LATITUDE 41.2 NORTH...
LONGITUDE 64.1 WEST OR ABOUT 240 MILES (385 KM) SOUTH OF HALIFAX NOVA
SCOTIA.”

HURRICANE JUAN ADVISORY NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM AST SUN SEP 28 2003
http://www.tpc.ncep.noaa.gov/archive/2003/pub/al152003.public.014.shtml?



Six hours later, the National Weather Service issued this correction
about Hurricane Juan’s official position:

“CORRECTED FOR INITIAL POSITION  44.5N 63.8W INSTEAD OF 45.8N 63.5N” 

and described its correct location in this manner:

“AT 11 PM AST...0300Z...THE CENTER OF HURRICANE JUAN WAS LOCATED NEAR
LATITUDE 44.5 NORTH...LONGITUDE  63.8 WEST.  THIS POSITION IS ON
THE COAST OF NOVA SCOTIA AND ABOUT 30 MILES...50 KM...SOUTHWEST OF
HALIFAX.”



Finally, this official advisory (#15), time stamped 11 PM AST SUN SEP
28 2003 was the last official reference by the National Weather
Service to “Hurricane” Juan.

JUAN ADVISORY NUMBER  15...CORRECTION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM AST SUN SEP 28 2003
http://www.tpc.ncep.noaa.gov/archive/2003/pub/al152003.public.015.shtml?


From that point forward, the National Weather Service referred to
former “Hurricane Juan” as “Tropical Storm Juan” as seen in Advisory
#16 time stamped 5 AM AST MON SEP 29 2003. This official change in
status appears to have taken place when “THE CENTER OF TROPICAL STORM
JUAN WAS LOCATED NEAR LATITUDE 47.8 NORTH...LONGITUDE  63.4 WEST OR
ABOUT 50 MILES...80 KM...NORTH-NORTHEAST OF NORTH POINT ON PRINCE
EDWARD ISLAND.”

TROPICAL STORM JUAN ADVISORY NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM AST MON SEP 29 2003
http://www.tpc.ncep.noaa.gov/archive/2003/pub/al152003.public.016.shtml?

In summary, since the weather advisories came at six-hour intervals,
and the storm appears to have downgraded during this period, it is
certainly safe to say that Hurricane Juan became Tropical Storm Juan
at some point between 11 PM AST SUN SEP 28 2003 and 5 AM AST MON SEP
29 2003 on the segment of its path between points 30 miles southwest
of Halifax, Nova Scotia and 50 miles North, Northeast of North Point,
Prince Edward Island.

If this serves to answer your question please let me know.

Best regards;
Tutuzdad-ga
Subject: Thank you tutuzdad-ga
From: brudenell-ga on 02 Oct 2003 05:31 PDT
 
Good morning

Your comment was quite informative and I appreciate your time taken to post.

Thank you.

Brudenell

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