ATL: IRENE - Remnants - Discussion

[Jevo]

9/25 6z Wind field.. pretty symmetrical



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9/25 6z Dvorak IR.. return of the first



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Edit: I just made Cat 2 on here.... that cant be a good sign

[CronkPSU]

even if the high is moving west, still looks like irene is on the right general NHC path, i don't see any major left hand turns in the last few hours

[ncweatherwizard]

Latest sterring chart 0300UTC still has a large gap to shoot through.
http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=



If she was a lot sallower.

http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

So I was told a few hours ago that this was a static picture and it wasn't showing how the trough was going to dig down and push the high to the east back. Well a few hours later it still shows a high closing off an eastward turn and looks to be steering it to SC/NC border area. In fact it looks like the high has pushed a little to the west from a few hours ago. How do I need to read this to make sense of it correctly the way the people in the know do?

So let's say the ridge stays in place (the static image). If the hurricane followed the periphery of mid-level ridging, then it could go right into SC. But what that image doesn't show is how the trough interacts with the ridge in the future. The ridging weakens--i.e. it becomes more north-south oriented and/or retreats eastward. So really that graphic gives you an idea of the steering flow at present. You need either model integration or some lucky guessing to estimate the future state.

Here's an example...sort of:

http://nencweather.com/tropicalweather/2010/Earl/EC.gif

Not very clear, but it's the first thing I thought of. From a post in the TA forum (viewtopic.php?f=29&t=109282) showing mid-level ridging weakening as Earl passed the EC last year. Of course, this is a different situation, and Irene will certainly strike somewhere.

[Ground_Zero_92]

Latest sterring chart 0300UTC still has a large gap to shoot through.
http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=



If she was a lot sallower.

http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

So I was told a few hours ago that this was a static picture and it wasn't showing how the trough was going to dig down and push the high to the east back. Well a few hours later it still shows a high closing off an eastward turn and looks to be steering it to SC/NC border area. In fact it looks like the high has pushed a little to the west from a few hours ago. How do I need to read this to make sense of it correctly the way the people in the know do?

So let's say the ridge stays in place (the static image). If the hurricane followed the periphery of mid-level ridging, then it could go right into SC. But what that image doesn't show is how the trough interacts with the ridge in the future. The ridging weakens--i.e. it becomes more north-south oriented and/or retreats eastward. So really that graphic gives you an idea of the steering flow at present. You need either model integration or some lucky guessing to estimate the future state.

Here's an example...sort of:

http://nencweather.com/tropicalweather/2010/Earl/EC.gif

Not very clear, but it's the first thing I thought of. From a post in the TA forum (viewtopic.php?f=29&t=109282) showing mid-level ridging weakening as Earl passed the EC last year. Of course, this is a different situation, and Irene will certainly strike somewhere.

Great explanation. So regardless of how the ridge looks now, you're saying that it is forecast to weaken and pull out. Right?

[CronkPSU]

isn't that ridge suppose to be dipping down though? seems like it is flatter, like it is just going to go the path of least resistance and scoot straight east above the ridge?

[bamajammer4eva]

Latest sterring chart 0300UTC still has a large gap to shoot through.
http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=



If she was a lot sallower.

http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

So I was told a few hours ago that this was a static picture and it wasn't showing how the trough was going to dig down and push the high to the east back. Well a few hours later it still shows a high closing off an eastward turn and looks to be steering it to SC/NC border area. In fact it looks like the high has pushed a little to the west from a few hours ago. How do I need to read this to make sense of it correctly the way the people in the know do?

So let's say the ridge stays in place (the static image). If the hurricane followed the periphery of mid-level ridging, then it could go right into SC. But what that image doesn't show is how the trough interacts with the ridge in the future. The ridging weakens--i.e. it becomes more north-south oriented and/or retreats eastward. So really that graphic gives you an idea of the steering flow at present. You need either model integration or some lucky guessing to estimate the future state.

Here's an example...sort of:

http://nencweather.com/tropicalweather/2010/Earl/EC.gif

Not very clear, but it's the first thing I thought of. From a post in the TA forum (viewtopic.php?f=29&t=109282) showing mid-level ridging weakening as Earl passed the EC last year. Of course, this is a different situation, and Irene will certainly strike somewhere.

True of course the NHC knows what they're doing even though it looks close. They would have some sort of watches up if there was even a chance they would be wrong. So apparently they are 100% sure the high is going to weaken.

[ncweatherwizard]

Great explanation. So regardless of how the ridge looks now, you're saying that it is forecast to weaken and pull out. Right?

Yes. The models are in very good agreement that the ridge will weaken because of an upper-level trough that will pass through the NE US on Thursday. A second trough, currently over British Columbia, will move into Eastern Canada in two to three days. This will help to prevent ridging from building back westward and forcing Irene farther inland.

[Texashawk]

000
URNT15 KNHC 250703
AF300 1909A IRENE HDOB 09 20110825
065330 1950N 06829W 3927 07720 0412 -176 -199 256009 010 /// /// 03
065400 1951N 06831W 3926 07728 0412 -179 -201 254011 012 /// /// 03
065430 1952N 06833W 3926 07727 0412 -179 -203 256011 012 /// /// 03
065500 1953N 06835W 3926 07726 0412 -180 -200 264011 012 /// /// 03
065530 1955N 06838W 3926 07728 0411 -180 -195 269013 014 /// /// 03
065600 1956N 06840W 3927 07728 0412 -178 -200 272013 014 /// /// 03
065630 1957N 06842W 3926 07728 0412 -177 -203 270014 014 /// /// 03
065700 1958N 06844W 3927 07724 0413 -175 -211 265013 013 /// /// 03
065730 1959N 06847W 3926 07725 0415 -175 -218 260012 013 /// /// 03
065800 2000N 06849W 3927 07725 0414 -175 -214 260011 012 /// /// 03
065830 2002N 06851W 3926 07730 0414 -175 -204 264010 011 /// /// 03
065900 2003N 06853W 3926 07727 0414 -175 -199 260010 011 /// /// 03
065930 2005N 06856W 3926 07734 0414 -175 -209 255010 010 /// /// 03
070000 2006N 06858W 3926 07740 0415 -174 -221 250010 011 /// /// 03
070030 2007N 06900W 3926 07727 0413 -174 -224 243009 009 /// /// 03
070100 2009N 06902W 3926 07729 0414 -174 -212 234008 009 /// /// 03
070130 2010N 06904W 3925 07731 0414 -175 -197 233008 008 /// /// 03
070200 2012N 06906W 3926 07726 0413 -174 -205 230007 008 /// /// 03
070230 2013N 06909W 3926 07730 0414 -170 -215 226004 005 /// /// 03
070300 2014N 06911W 3926 07729 0414 -170 -218 224006 006 /// /// 03
$$
;

[kamqercam]

It honestly feels like this thing is zeroing in onto my location (Oak Island, NC) with all the shifts right right right and now looking left left. I think I'm going to go ahead and feel up all the gas containers and get things prepared tomorrow. I also need to get my license renewed! Aug 28th I will be 30 lol.

[CronkPSU]

someone posted this link a while back...it seems to update about 45 minutes before the noaa loops and even quicker than the nasa links and is probably pretty good for tracking Irene as she has finally come into the picture

http://aviationweather.gov/adds/satellite/displaySat.php?region=TPA&isingle=mult_big&itype=ir

[ncweatherwizard]

True of course the NHC knows what they're doing even though it looks close. They would have some sort of watches up if there was even a chance they would be wrong. So apparently they are 100% sure the high is going to weaken.

Watches will likely be posted Thursday by lunchtime. Even through ridging will weaken, a significant threat remains to everyone from NC northward. Technically, tropical storm watches are issued when TS conditions are possible within 48 hours. Ditto for hurricane watches. I wouldn't be surprised though if NHC takes advantage of the forecast confidence and issues a Hurricane Watch a little early for most of the N. Carolina coast on Thursday morning. TS Watch will be issued for a good bit of the S. Carolina coast as well. Watches will extend northward later in the day.

[Texashawk]

000
URNT15 KNHC 250713
AF300 1909A IRENE HDOB 10 20110825
070330 2016N 06913W 3927 07732 0413 -168 -208 211006 006 /// /// 03
070400 2017N 06915W 3926 07726 0412 -167 -207 203007 007 /// /// 03
070430 2018N 06917W 3926 07726 0413 -169 -220 199007 007 /// /// 03
070500 2020N 06920W 3926 07724 0412 -169 -208 186007 008 /// /// 03
070530 2021N 06922W 3926 07726 0412 -167 -197 169008 009 /// /// 03
070600 2023N 06924W 3926 07731 0413 -170 -206 175007 008 /// /// 03
070630 2024N 06926W 3926 07728 0412 -170 -206 161007 009 /// /// 03
070700 2026N 06929W 3927 07722 0411 -166 -205 145010 010 /// /// 03
070730 2027N 06931W 3925 07725 0412 -165 -214 145008 009 /// /// 03
070800 2028N 06933W 3926 07726 0409 -166 -234 147009 009 /// /// 03
070830 2030N 06935W 3926 07724 0409 -170 -227 157010 011 /// /// 03
070900 2031N 06938W 3925 07726 0409 -174 -206 182011 012 /// /// 03
070930 2033N 06940W 3926 07729 0408 -173 -202 176011 011 /// /// 03
071000 2034N 06942W 3925 07727 0407 -173 -211 184008 010 /// /// 03
071030 2035N 06944W 3926 07719 0406 -175 -206 208008 009 /// /// 03
071100 2037N 06947W 3926 07723 0407 -175 -199 209008 008 /// /// 03
071130 2038N 06949W 3926 07720 0407 -175 -207 207009 010 /// /// 03
071200 2040N 06951W 3926 07720 0406 -171 -211 206010 010 /// /// 03
071230 2041N 06954W 3925 07722 0406 -176 -201 209011 011 /// /// 03
071300 2043N 06956W 3926 07720 0406 -179 -195 213011 011 /// /// 03
$$
;

[myred]

Ok I am not a board mod, but this bickering needs to stop. There is a potential catastrophic hurricane headed to various places and snow has nothing to do with hurricanes. Please get back on topic so those who are trying to find out useful and needed information can find it. Thanks!!

Well, actually this is very useful information. Let me explain why. I personally have lived in Florida for 20 years and in the New York/ New Jersey area for 30 years. people up north only have snow storms to compare to hurricanes because we don't get hurricanes up here. The big difference between a nor'easter and a hurricane is time of year.

This is not for NYC itself, but rather for the millions of people who just live in the burbs in the northeast.
During the winter, the ground is frozen and there are no leaves on the trees. All outdoor stuff is tucked away safely for the winter. The wind blows during a snow storm 50, 60 or 70 mph and some trees fall, but all in all, things stay standing.

In the summer, it is totally different. The ground is already saturated, The trees are in full bloom and they act like giant sails. People have projectiles all over their yards. There is a huge demand on the power grids running air conditioning. Almost everyone has overhead power lines rather than underground up here.

In my opinion, The bottom line is, if the northeast gets a direct hit from Irene it will be much worse than any nor'easter they have seen. Power outages will be a much longer duration, roads will be impassible due to flooding and trees down and water supplies could be contaminated. People up here, must take this storm seriously because this is not a snowstorm, it is a hurricane.

Thank you for a logical explanation of the effects, making more sense since you have lived in both the Noreaster zone and the Hurricane zone.
Short on rhetoric and long on logic.
Thanks!

And my biggest concern is that no one I Know up here is taking this seriously enough. If this where a nor'easter, the stores would be buzzing by now and as of last night, they where not. We get a good 5 to 7 day notice on the path of a classic nor'easter. With a nor'easter, you get two days of "milk and bread" and everyone is good to go. If they do that for Irene preparations, allot of folks could be really hurting within the first 3 days post storm, if it where, a direct hit on us.

[WxGuy1]

In Houston, we used to get the sage wisdom of Dr. Neil Frank, the former NHC director. I remember him talking about a certain storm a while back (Gilbert?) that was basically so large and powerful that it did what it wanted - he described it as a boulder in a river, where normal hurricanes are small rocks that are carried by the river. But with that storm, it was effectively a boulder that essentially ignored the river and cut its own path. Is Irene going to be a boulder, and would modern models account for that?

In the end, even a huge hurricane obeys physics. The set of the most "important" equations for weather forecasts (momentum equations, continuity equation, thermo. eqn, etc) still hold no matter how strong or weak, large or small, or slow or fast the tropical cyclone is. So, if a hurricane plows through a ridge, it's doing so because, despite how odd it may seem, the physics dictate that the storm takes that path. The models that we use now include all of these basic (not necessarily simple!) equations. A lot of the small-scale details are too small to be explicitly forecast by most of the major models you read about and use for tropical cyclone forecasting, so they make use of what are called "parameterizations", which are, essentially, sets of assumptions and estimates used to generalize these small-scale effects/influences/patterns into scales large enough to "fit" into the model. For example, the GFS cannot actually forecast individual 5-mile-wide thunderstorms that are rotating into the hurricane in the spiral bands -- it's forecasting what it thinks the "larger" environment (say, 30-40 mile areas) will look like with those storms around. However, there are times when these parameterizations fail (in terms of accuracy), and there are times when some processes that may typically not affect much may grow to become important in the actual path of a hurricane.

Differences in the parameterizations used amongst the different models, along with differences in the numerics (spatial and temporal discretizations), can account for some of the differences you see between the forecasts from different models (ECMWF, GFS, NAM, NOGAPS, UKMET, etc.). Of course, it's also important to know that the initial conditions (that is, what each model thinks the atmosphere is like right now) can also be difference, largely because we don't actually have weather data for every spot in the atmosphere at every time. As a result, different analysis schemes (which may use different data) are needed and used by the different models. Since the atmosphere is very non-linear, very small errors even in the analysis can grow to lead to massive errors in a 5-day forecast.

[Texashawk]

000
URNT15 KNHC 250723
AF300 1909A IRENE HDOB 11 20110825
071330 2044N 06958W 3926 07721 0406 -180 -197 221012 012 /// /// 03
071400 2045N 07000W 3926 07719 0407 -175 -198 222013 013 /// /// 03
071430 2047N 07003W 3926 07719 0407 -175 -201 233013 014 /// /// 03
071500 2048N 07005W 3925 07726 0407 -175 -203 237013 014 /// /// 03
071530 2050N 07007W 3926 07723 0407 -175 -199 237014 015 /// /// 03
071600 2051N 07010W 3927 07716 0407 -175 -196 236013 014 /// /// 03
071630 2052N 07012W 3926 07720 0406 -175 -197 232011 012 /// /// 03
071700 2054N 07014W 3926 07718 0406 -175 -198 227010 010 /// /// 03
071730 2055N 07016W 3926 07722 0406 -175 -197 228011 012 /// /// 03
071800 2056N 07019W 3926 07724 0405 -175 -196 225012 012 /// /// 03
071830 2058N 07021W 3926 07723 0406 -174 -191 215011 012 /// /// 03
071900 2059N 07023W 3926 07722 0405 -170 -194 212013 013 /// /// 03
071930 2101N 07025W 3926 07720 0403 -170 -200 215013 013 /// /// 03
072000 2102N 07028W 3926 07718 0403 -170 -204 215013 014 /// /// 03
072030 2103N 07030W 3926 07719 0403 -170 -203 211014 015 /// /// 03
072100 2105N 07032W 3926 07719 0403 -170 -199 208014 015 /// /// 03
072130 2106N 07034W 3926 07720 0404 -170 -199 209015 016 /// /// 03
072200 2107N 07037W 3926 07714 0404 -170 -202 197014 014 /// /// 03
072230 2109N 07039W 3926 07720 0404 -170 -202 183014 014 /// /// 03
072300 2110N 07041W 3926 07717 0404 -170 -204 177014 014 /// /// 03
$$
;

[MWatkins]

Wxguy1

One of the best posts I have ever read on S2K. We've come a long way in the last 20 years, and I don't think we completely understood the dynamics of a hurricane "feeding" the ridge like we do now, and the physics of that interaction has been captured by the modern dynamical models.

This might be one of the reasons (along with the amplification of the trough west of Irene) that the models are starting to correct back to the west.

Again, outstanding answer. Really, really appreciate the detailed insight, and the excellent explanation.

MW

[Texashawk]

WxGuy1,

Wow. Thanks for the detailed insight. I do think it was Gilbert - so this would be in 1988? Obviously, our understanding of synoptic modeling has come a long way in 20-25 years. I still remember when weather forecasters would always say, "Don't forget, hurricanes are very unpredictible - you don't really know what they'll do." Now, I guess we're getting closer to cracking the 'code' of hurricane prediction. Incredible how far weather science has come in two decades. Thanks again.

[Texashawk]

000
URNT15 KNHC 250733
AF300 1909A IRENE HDOB 12 20110825
072330 2112N 07044W 3925 07721 0405 -170 -204 174014 014 /// /// 03
072400 2113N 07046W 3926 07716 0404 -170 -204 176013 013 /// /// 03
072430 2115N 07048W 3925 07720 0404 -171 -202 189013 014 /// /// 03
072500 2116N 07051W 3926 07721 0404 -170 -199 185013 013 /// /// 03
072530 2117N 07053W 3926 07718 0403 -170 -203 178013 014 /// /// 03
072600 2119N 07055W 3926 07719 0402 -170 -201 179014 015 /// /// 03
072630 2120N 07058W 3926 07719 0403 -170 -197 179014 015 /// /// 03
072700 2122N 07100W 3926 07712 0402 -171 -196 176013 014 /// /// 03
072730 2123N 07102W 3926 07717 0399 -172 -194 169014 014 /// /// 03
072800 2124N 07105W 3925 07714 0400 -174 -192 168013 013 /// /// 03
072830 2126N 07107W 3926 07713 0398 -175 -189 169012 013 /// /// 03
072900 2127N 07109W 3926 07713 0399 -171 -191 160012 012 /// /// 03
072930 2129N 07112W 3927 07712 0399 -170 -195 157013 014 /// /// 03
073000 2130N 07114W 3926 07714 0398 -170 -201 161012 012 /// /// 03
073030 2131N 07117W 3926 07714 0398 -170 -198 161011 012 /// /// 03
073100 2132N 07119W 3926 07714 0399 -170 -189 163012 013 /// /// 03
073130 2134N 07122W 3926 07717 0401 -170 -195 162012 013 /// /// 03
073200 2135N 07124W 3926 07718 0402 -170 -207 162013 013 /// /// 03
073230 2136N 07127W 3926 07719 0403 -169 -204 162013 013 /// /// 03
073300 2138N 07129W 3925 07719 0402 -167 -200 169015 016 /// /// 03
$$
;

[Texashawk]

000
URNT15 KNHC 250743
AF300 1909A IRENE HDOB 13 20110825
073330 2139N 07131W 3927 07715 0402 -167 -204 175015 016 /// /// 03
073400 2140N 07134W 3926 07717 0402 -168 -208 175014 014 /// /// 03
073430 2142N 07136W 3927 07714 0401 -165 -201 173014 015 /// /// 03
073500 2143N 07139W 3926 07714 0400 -165 -209 170015 015 /// /// 03
073530 2144N 07141W 3926 07713 0399 -166 -226 189017 017 /// /// 03
073600 2145N 07144W 3926 07713 0399 -163 -219 194017 018 /// /// 03
073630 2147N 07146W 3928 07711 0399 -160 -214 192018 019 /// /// 03
073700 2148N 07149W 3926 07714 0399 -163 -224 191019 019 /// /// 03
073730 2149N 07151W 3926 07714 0399 -166 -214 194019 019 /// /// 03
073800 2151N 07153W 3926 07713 0399 -165 -213 193018 019 /// /// 03
073830 2152N 07156W 3927 07712 0398 -163 -229 193017 017 /// /// 03
073900 2153N 07158W 3926 07713 0397 -160 -264 191018 018 /// /// 03
073930 2154N 07201W 3926 07711 0396 -163 -297 188020 020 /// /// 03
074000 2156N 07203W 3926 07710 0395 -161 -302 194019 019 /// /// 03
074030 2157N 07206W 3926 07710 0393 -162 -318 191018 019 /// /// 03
074100 2158N 07208W 3926 07707 0392 -165 -319 191019 019 /// /// 03
074130 2200N 07210W 3926 07707 0392 -165 -288 191020 020 /// /// 03
074200 2201N 07213W 3926 07707 0391 -165 -283 192020 020 /// /// 03
074230 2202N 07215W 3926 07704 0389 -165 -317 190020 020 /// /// 03
074300 2203N 07218W 3926 07704 0389 -166 -358 192021 021 /// /// 03
$$
;

[Texashawk]

It certainly looks like Irene is going to miss her next point - probably 50 miles to the south. Interesting.