NHC increases hurricane forecast lead times

By: Dr. Jeff Masters , 7:27 PM GMT on January 05, 2010

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The National Hurricane Center (NHC) announced today that beginning with the 2010 hurricane season, their hurricane and tropical storm watches and warnings for the U.S. coast will be extended in time by an additional 12 hours. Warnings will now be issued 36 hours in advance instead of 24 hours, and watches will be issued 48 hours in advance, instead of 36 hours. The increase in lead time for watches and warnings has been made possible by the tremendous improvement in hurricane track forecasts, which have improved by over 50% in the past twenty years (Figure 1). "With increases in population and infrastructure along vulnerable U.S. coastlines, emergency managers need more lead time in order to make life-saving decisions regarding evacuations", said Bill Read, director of NOAA's National Hurricane Center, in today's press release.


Figure 1. Average track errors for NHC Atlantic tropical storm and hurricane forecasts issued between 1990 - 2008. Track errors have improved by over 50% in the past 20 years. Image credit: National Hurricane Center.

Commentary
NHC has been debating for a number of years how best to "invest" the gains accrued from the steady improvement in hurricane track forecasts. One obvious savings from these better hurricane forecasts has come from the reduced evacuation costs. When a hurricane warning is issued 24 hours before the expected arrival of hurricane-force winds at the coast, it costs approximately $1 million to evacuate each mile of U.S. coast warned (Aberson et al., 2006). This number will be higher for more densely populated areas of the coast, such as Miami, and may be a factor of six lower for the North Carolina coast (Whitehead, 2003). According to a 2007 presentation at the 61st Interdepartmental Hurricane Conference, the length of coast warned decreased significantly in the past decade. During the decade of the 1990s, the average length of a hurricane warning was 455 miles, but that fell to just 335 miles between 2000 - 2006. Thus, an average of 120 fewer miles of coast were warned, at an average savings of $120 million per hurricane warning issuance. During this period, 17 storms requiring 25 hurricane warnings occurred. If the costs of coastal evacuations are indeed $1 million per mile, the improved hurricane forecasts between 2000 - 2006 resulted in savings of $3 billion compared to what the forecasts of the 1990s would have cost.

However, the new increased lead times for hurricane watches and warnings will lead to an increase in the length of coast warned, due to the higher uncertainties in hurricane tracks at longer forecast lead times. Between 2004 - 2008, approximately 25% of the coast that was placed under a hurricane warning actually received hurricane force winds; this percentage was 20% for areas placed under a hurricane watch. These percentages will decline with the new increased watch and warning lead times, costing money in unnecessary evacuations, and leading to increased complacency in the warned population due to too much "crying wolf".

Balanced against these increased costs is the potential disastrous loss of life should a hurricane hit an unprepared, heavily populated shoreline. With the U.S. population continuing to increase rapidly in coastal regions, the time needed to evacuate vulnerable populated regions is increasing. For example, evacuation times for the major urban areas of Texas are 28 - 34 hours for a major hurricane. Though the costs of overwarning the coast is significant, the savings in both human lives and dollars from increased warning times should outweigh these costs. In the 2002 book, Hurricane: Coping With Disaster, Dr. Hugh Willoughby, former director of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Marine Laboratory, analyzed hurricane death statistics. In 1950, about 70 U.S. residents died per year in hurricanes. In the 50 years since, the coastal population expanded by a factor of 3.2, so if we were managing the hurricane problem the way we did in 1950, we would be losing about 220 people a year. The long-term average is still about twenty per year, not including the deaths due to the levee failures during Katrina. That means we're preventing about 200 deaths per year compared with 1950. How much are these saved lives worth? A life, is, of course, priceless, but in the cold world of economics, the value of life-saving scientific research and government regulations is estimated using statistics of what people are willing to pay to avoid certain risks, and what extra money employers pay their workers to take on additional risks. This data comes primarily from payroll statistics, but opinion surveys also play a role. In 2004, the Environmental Protection Agency (EPA) valued an American life at $8 million. EPA cut the value of a life by 8% that year, and a further 3% in May 2008, making the economic value of a life $6.9 million in today's dollars. The Department of Transportation gives a lower figure of a life as being worth $5.8 million. Using this number implies a savings of about $1.2 billion per year for the 200 lives saved per year by better hurricane warnings and evacuations. Today's decision by NHC to increase warning times should continue this trend of saving lives, which will also provide considerable monetary benefit. Despite the increased costs and dangers of "crying wolf" too often due to overwarning the coast, I believe that the double value of saving lives--for both the intrinsic and monetary value of a human life--makes NHC's move of increasing warning and watch times the right call.

References
Whitehead, J.C., 2003: "One million dollars per mile? The opportunity costs of Hurricane evacuation", Ocean and Coastal Management 46, 1069.

I'll have a new post on Thursday or Friday.

Jeff Masters

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1239. unf97
Going to get some shut-eye for now. As I turn in for some sleep, the temperature now down to 25.2 degrees in north Jax.

Back on in awhile to check the updated model runs!

Have a good night/early morning everyone.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
RIGHT. 58 on my porch. Mets haven't updated yet. Ah, they're still saying 59, which I can't believe.....

g'nite!
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Extremely weird. I was outside, smoking a cigarette, and the Severe Weather Sirens were going off!

The leading edge of the Arctic Cold Front is moving through the Dallas-Ft Worth, TX area from NW to SE.

The Ft Worth Naval Air Station has N winds at 25 G 33MPH.

Arlington AP has SW winds at 6MPH.

Gonna get nasty cold, quick!
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1236. ABlass
Quoting Bordonaro:


The battle of the air masses!

The warmer, moist air to the south, which is lighter, moves north, up and over the cold air. Then, the cold, dry air, which is more dense (heavier) tries to sink southward, forcing the warm air up in front of it. Add the Earth's rotation and you have storms develop. These storms help move the Jet Streams north and southward.


Thank you very much. I think I've got it now :)
Think I better go throw another log on the fire :)
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Quoting JGreco:
Did anybody see the moderation of the forecast the NWS has made? It looks to be trending away from the snow event yet everybody is getting excited about the surge in moisture. Please explain?


well i notice they went rain/sleet if that for now for tonight.. it will b interesting tomorrow or later today how it will play out.. The moisture we r talking is the sw over central and southern mexico/southern texas slightly.. That moisture is looks like is heading in with that jet stream into GOM from what I can gather.. It could b possible that it can make it through.. we will c..
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1234. unf97
Quoting Bordonaro:


I lived in Arlington, TX in Dec 1989, I remember that airmass. It literally poured in, stayed 2 days and it was gone. The heart of the High parked over Dallas-Ft Worth, TX. We recorded a pressure of 30.99".

This scenario is different, the core of High pressure will take 2 1/2 days to come into E TX/W LA. The 1989 outbreak the High arrived in 24 hrs. The upper levels will gradually moderate the airmass. It will be cold, some records will fall, but not all of them, like in 1989.


There is a sufficient snowpack in place over the Northern Plains and Midwest that is keeping these arctic air masses from moderating rapidly though. You may be right Bordonaro, but based on current trends, I am inclined to think that moderating this 1055mb High coming down over that snowpack will continue to be a very slow process. It may be as late as Tuesday of next week before we see significant moderation in the Eastern CONUS.

It is fascinating nonetheless seeing these extreme patterns evolve.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
1233. JGreco
Did anybody see the moderation of the forecast the NWS has made? It looks to be trending away from the snow event yet everybody is getting excited about the surge in moisture. Please explain?
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Quoting unf97:


Let's put this in perspective. This current Siberian High centered over the Canadian province of Saskatchewan has a pressure of 1055 mb. This is such an extremely impressive bitterly cold air mass that is on the way plunging down into the Central and Eastern CONUS.

During the big Arctic outbreak of December 22-24 1989, a Siberian High of 1052 mb dropped down out of the same region of Canada into the Northern Plains, and of course we all know what came to happen.

This current Arctic surge coming down over the next few days is similar to the very extreme pattern from Dec'89. This could be another outbreak for the record books as the potential is there for this to be every bit as impressive as the Dec.'89 outbreak. This set-up looks eerily similar.


I lived in Arlington, TX in Dec 1989, I remember that airmass. It literally poured in, stayed 2 days and it was gone. The heart of the High parked over Dallas-Ft Worth, TX. We recorded a pressure of 30.99".

This scenario is different, the core of High pressure will take 2 1/2 days to come into E TX/W LA. The 1989 outbreak the High arrived in 24 hrs. The upper levels will gradually moderate the airmass. It will be cold, some records will fall, but not all of them, like in 1989.
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Quoting Bordonaro:


Normally, the Deep South and Florida have mild winters. Normally, Florida has a "winter dry season", the Deep South has regular rounds of showers, an occassional freeze, nothing too dramatic.

Stage Left, Modiki El Nino, the weather patterns are "warming the Arctic" and dumping their normal airmasses from Siberia into the Eastern 2/3 of the US. The Central Pacific and the Equatorial regions near Peru are warmer than usual.

All I can say is check on the Forecast Discussions and check the NAM/GFS model runs, maybe everything will fall into place!


thanks will do..btw i have, most r different between models and the forecast discussion.. i guess it b 6hours b4 i know what will happen..lol
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1230. unf97
Quoting FLPandhandleJG:


looks like L is trying develop moisture and starting to make its move and head towards the GOM..


Yeah, I have been watching that trend. Also,interesting to note is a feed streaming NE from the disturbance in the EPAC. How much of that moisture and energy ripples along through the southern stream jet in the next few days toward the GOM?
Member Since: September 25, 2007 Posts: 0 Comments: 1193
I haven't been to Nashville in a few years so I need to head that way sometime soon. I really love the city and miss living there - even though I sure hated to go to work when it snowed..if the buses ran then you went to work!..lol
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Quoting FLPandhandleJG:


O gotcha.. ya Im trying to figure this possible snow event out.. freaking south is wishy washy.. haha


Normally, the Deep South and Florida have mild winters. Normally, Florida has a "winter dry season", the Deep South has regular rounds of showers, an occassional freeze, nothing too dramatic.

Stage Left, Modiki El Nino, the weather patterns are "warming the Arctic" and dumping their normal airmasses from Siberia into the Eastern 2/3 of the US. The Central Pacific and the Equatorial regions near Peru are warmer than usual.

All I can say is check on the Forecast Discussions and check the NAM/GFS model runs, maybe everything will fall into place!
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1227. unf97
Quoting Bordonaro:
The Siberian Monster has a Central Pressure of 1055MB/31.15"..BIG BAD FRIGID HIGH...



Let's put this in perspective. This current Siberian High centered over the Canadian province of Saskatchewan has a pressure of 1055 mb. This is such an extremely impressive bitterly cold air mass that is on the way plunging down into the Central and Eastern CONUS.

During the big Arctic outbreak of December 22-24 1989, a Siberian High of 1052 mb dropped down out of the same region of Canada into the Northern Plains, and of course we all know what came to happen.

This current Arctic surge coming down over the next few days is similar to the very extreme pattern from Dec'89. This could be another outbreak for the record books as the potential is there for this to be every bit as impressive as the Dec.'89 outbreak. This set-up looks eerily similar.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Will this weekend be any colder than current in the SE US?
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1225. Patrap
Put yer mittens and seat belts on the Next 72-96,itsa gonna get Bumpy in Dixie.




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Quoting AllyBama:
thanks Bordonero..just wishing I was going to be in Nashville tonight!..lol


I am back in Ft Worth, TX now. My daughter is in Nashville, TN. She said it has been miserable and cold, temps from 10-25F for a week, and they're receiving about 3" of snow tomorrow.
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Quoting Bordonaro:


Doing well. I am waiting for my "Midnight Siberian Express Flight #-30", to move in. The suspense is "killing me"!! It's about 30 miles N of the Dallas-Ft Worth, TX AP..


O gotcha.. ya Im trying to figure this possible snow event out.. freaking south is wishy washy.. haha
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GO MOISUTRE GO!..LOL
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looks like L is trying develop moisture and starting to make its move and head towards the GOM..
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1220. JGreco
It looks like the NWS have finally backed off on the snow prediction and call for a 50% chance of sleet or rain on Thursday night with snow only making as far east as Mobile. Hopefully things change..sigh...
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1219. Patrap
Special Weather Statement

Statement as of 11:16 PM CST on January 06, 2010

... Extended cold snap and possible record cold resumes Thursday
night through Sunday...
... A brief period of light wintry precipitation is possible
mainly in south Mississippi and upper southeast Louisiana
Thursday late afternoon...

Tonight will be a relatively warmer night than the past couple of
nights and a freeze is not expected. Clouds will will prevail
overnight and light rain will be possible toward daybreak Thursday.
A cold rain is expected for much of the area Thursday in advance of
a strong surge of Arctic air currently moving through the Great
Plains states. The dense cold air will flush the rain out of the
area but in doing so... may briefly transition to a mix of light
sleet and light snow with little or no accumulation before ending
Thursday afternoon or early evening. The area most likely to see
these conditions may be limited to the southwest Mississippi
counties and the adjacent Florida parishes. South of this area
temperatures should be warm enough to preclude winter precipitation.

The Arctic air will be the coldest this far south since February
1996 and will have a long duration impact for each night Thursday
night through Saturday night. Area temperatures may undergo freeze
durations of 12 to 16 hours each night... generally from shortly
after sunset until about mid-morning. Areas within hard freeze
warnings can experience those conditions for durations of 8 to 10
hours each night.

Some areas may experience record tying or record breaking low
temperatures. The following table is a listing of record minimum
temperatures for select locations in southeast Louisiana and
southern Mississippi.

Record minimums

Site Fri 1/8 Sat 1/9 sun 1/10 Mon 1/11
Baton Rouge 20/1970 17/1979 12/1962 10/1982
New Orleans area 17/1970 22/1970 16/1962 14/1962
McComb 16/1996 14/1979 7/1962 5/1962
Gulfport naval 20/1996 19/1979 15/1962 8/1982
Pascagoula (coop)20/1996 19/1996 22/1996 8/1982
Slidell 20/1970 19/1979 15/1962 9/1962
Audubon 25/1970 24/1958 15/1962 13/1962
Houma 21/1970 23/1970 16/1962 12/1962


In addition... the combination of very cold temperatures and wind will
produce very cold wind chill readings from 5 to around 10 degrees
Friday night and Saturday morning... and from around 10 to 15 degrees
Saturday night and Sunday morning. A Wind Chill Advisory may be
required Friday night and Saturday night.

Everyone in south Mississippi and south Louisiana should bring to
completion all freeze preparedness measures before sunset Thursday.
This includes the wrapping and protecting of exposed pipes... the
protection of sensitive plants and crops... the safe shelter of
outdoor pets and farm animals... and the care of individuals
vulnerable to the elements. Inspection and proper application of
heating equipment is urged to avoid fires and Carbon monoxide
poisoning. Also... dress appropriately for extended outdoor
exposure to the cold.
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thanks Bordonero..just wishing I was going to be in Nashville tonight!..lol
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Quoting BtnTx:
does anyone use the chat?

Generally, everyone watches the blog, and/or asks questions in it. I have honestly never used the chat, and I've been a lurker on here for a good 3 years, and an actual paid member for 18 months.
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Quoting FLPandhandleJG:


Hey Bob.. how u doing sir?


Doing well. I am waiting for my "Midnight Siberian Express Flight #-30", to move in. The suspense is "killing me"!! It's about 30 miles N of the Dallas-Ft Worth, TX AP..
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Quoting Bordonaro:


Certainly, feel free to ask questions, there are alot of weather watchers, like myself who can help. Mr "atmoaggie" is a meteorologist, "StormW" is also very, very knowlegable. you can alwayssend them a WU e mail and they'll respond.


Hey Bob.. how u doing sir?
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Quoting AllyBama:
well, looks like the NWS boys are dragging their feet again tonight...guess they know how disappointed alot of us are now that our chances of snow are dropping dramatically..I like it better when we had a 60-70% chance..:(


Ally, they really do not know what exactly is going to happen. Snow is so rare in the Deep South. They will do "soundings", or readings of what is going on in the atmosphere from the ground up to 18,000+ FT, using "Mr of MS Weather Balloon", look at the computer models and put out a forecast, probably just before or after the cold front storms in.
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1213. Patrap
ESL by LSU GOES GOM IR Loop


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Quoting BtnTx:
Thanks Bordonaro


Certainly, feel free to ask questions, there are alot of weather watchers, like myself who can help. Mr "atmoaggie" is a meteorologist, "StormW" is also very, very knowlegable. you can alwayssend them a WU e mail and they'll respond.
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1211. BtnTx
Thanks Bordonaro
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well, looks like the NWS boys are dragging their feet again tonight...guess they know how disappointed alot of us are now that our chances of snow are dropping dramatically..I like it better when we had a 60-70% chance..:(
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Quoting BtnTx:
does anyone use the chat?


Occasionally, especially during the heart of Hurricane Season, or a major winter/spring storms.
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The Siberian Monster has a Central Pressure of 1055MB/31.15"..BIG BAD FRIGID HIGH...

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1207. BtnTx
Quoting Bordonaro:


Do you have a specific question, feel free to ask and I will try to answer it for you!
does anyone use the chat?
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Member Since: October 1, 2007 Posts: 81 Comments: 26511
11PM CST Weather Obs from NW TX, about 80 to 150 miled west of Dallas-Ft Worth, TX: NOTE the Wind Speeds:


CITY SKY/WX TMP DP RH WIND PRES REMARKS
WICHITA FALLS LGT SNOW 30 28 92 N36G44 30.24R FOG WCI 14
WF-KICKAPOO LGT RAIN 34 32 91 N29G36 30.22R WCI 20
VERNON CLOUDY 29 22 76 N28G40 30.29R WCI 14
ABILENE CLOUDY 36 30 79 N23G33 30.17R WCI 24
ABILENE-DYESS CLOUDY 36 31 81 N16G28 30.16R WCI 26
BRECKENRIDGE CLOUDY 40 33 78 N18G29 30.13R WCI 31
GRAHAM CLOUDY 38 32 77 N28G38 30.13R WCI 27
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Quoting BtnTx:
The response to my previous post asking about weather chat was overwhelming! I will exit w/o reply as it is late


Do you have a specific question, feel free to ask and I will try to answer it for you!
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Quoting ABlass:

Thank you muchly :)
Hope you have patience for another ? What causes the jetstream to shift positions?


The battle of the air masses!

The warmer, moist air to the south, which is lighter, moves north, up and over the cold air. Then, the cold, dry air, which is more dense (heavier) tries to sink southward, forcing the warm air up in front of it. Add the Earth's rotation and you have storms develop. These storms help move the Jet Streams north and southward.
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1202. BtnTx
The response to my previous post asking about weather chat was overwhelming! I will exit w/o reply as it is late
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By Monday there should be a wikipedia article on the Artic outbreak of Early Jan 2010. Especially if some winter weather sneaks into Fla.
Member Since: September 6, 2009 Posts: 2 Comments: 3768
Quoting Orcasystems:
For the people from Florida... I put a post in my Blog #768, it explains what that mysterious button or switch is, thats in your dashboard.Its called a DEFROSTER. The insignia for the front window defrost looks just like the front window. The one for the back window looks just like the back window; these features normally have three settings: low, medium and high


xD LOL. When I had the car for high school, many a time i used the defroster to dry the back window up from thick morning dew.
Member Since: September 6, 2009 Posts: 2 Comments: 3768
1198. ABlass
Quoting Bordonaro:


That was a GOOD question, not a stupid question. The warm and cool airmasses/ocean currents interacting causes the Jet Streams to move.

Check this link, then click on the buttons on the left. It puts the atmosphere in motion to see how it works.

Link

Thank you muchly :)
Hope you have patience for another ? What causes the jetstream to shift positions?
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Tallahassee airport reporting 24 degrees yet the main one i use for Tallahassee has it just below freezing at 31.6 its been stuck around that for a while, maybe it went kaput from the temps lol.
Member Since: September 6, 2009 Posts: 2 Comments: 3768
Quoting StSimonsIslandGAGuy:


It can get into the 20s at night in Mexico City occasionally--they are almost 8,000 feet above sea level.

Link


Wow it doesn't even get that hot either.
Member Since: September 6, 2009 Posts: 2 Comments: 3768
I think the new GFS models r being updating now.. so i will post them once there up..
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1193. BtnTx
does anyone ever go to weather chat?
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Almost here, Siberian Express, bringing ICE cold temps to everyone in Texas:

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SHORT TERM FORECAST
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1129 PM EST WED JAN 6 2010

INZ028-029-035-036-043-044-051-052-060-061-067-068-070800-
CLAY-DAVIESS-FOUNTAIN-GREENE-KNOX-MONTGOMERY-PARKE-SULLIVAN-
TIPPECANOE-VERMILLION-VIGO-WARREN-
INCLUDING THE CITIES OF...CRAWFORDSVILLE...LAFAYETTE...TERRE HAUTE...
VINCENNES
1129 PM EST WED JAN 6 2010

.NOW...
SNOW WILL BE MOVING INTO WEST CENTRAL INDIANA SHORTLY AFTER
MIDNIGHT. TWO INCHES OF ACCUMULATION ARE LIKELY BY DAYBREAK.
MOTORISTS SHOULD ALLOW EXTRA TIME TO GET TO WORK IN THE MORNING AS
SLICK AND SNOW COVERED ROADS ARE EXPECTED.

$$

KOCH


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Quoting ABlass:
It's going to be a cool one tonite:

Forecast

Issued: 8.41 PM MST Wednesday 6 January 2010
Wind chill warning in effect.

Tonight:
Clear. Ice fog patches. Wind up to 15 km/h. Low minus 30C (-22F). Extreme wind chill minus 41C (-41.8F).

Think I will just hunker down for the evening :)

A quick (probably dumb)noob question I haven't been able to find an understandable answer to: What causes the jetstream to move?


That was a GOOD question, not a stupid question. The warm and cool airmasses/ocean currents interacting causes the Jet Streams to move.

Check this link, then click on the buttons on the left. It puts the atmosphere in motion to see how it works.

Link
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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