Hurricane Irene

[IsentropicLift]

The only people that should be "frustrated" here are those that model hug too much and ignore the repeated messages from the NHC regarding track error. The average day 5 track error is 250 miles.

Still, if anyone here is thinking this is a done deal you obviously didn't learn anything from past winter. It's very possible that the exact track lies somewhere between the LI brush fish scenario and the doomsday scenario the EC has been preaching and only now with the better data the models are starting to settle on a track which brings the center into eastern LI.

There was alot of discussion on the main forum about the 00z GFS being questionable. I wonder if the added dropsone data has actually caused more havoc on the models than good. It's not a shocker to me that the 06z GFS came a bit west, even given the fact that its based off of old data, and I wouldn't be suprised to see it jog west again at 12z.

When we are 48 hours out and the system is 300 miles off VA beach heading NE its safe to call game, set, match. But until that point, your only making yourself look foolish by taking every single model run verbatim as if it were a life a death situation. The weeniesm has been something awful. If you can't explain your comment, its probably best to not comment at all. You look at the other sub forums and its loaded with red taggers. Thats not the case here. I wonder why...or not.

[Sickman]

I'd like to remind everyone that this is the official obs thread. There's a banter thread for the other stuff.

Help us out, and post accordingly please. Thanks.

[bates]

The only people that should be "frustrated" here are those that model hug too much and ignore the repeated messages from the NHC regarding track error. The average day 5 track error is 250 miles.

Still, if anyone here is thinking this is a done deal you obviously didn't learn anything from past winter. It's very possible that the exact track lies somewhere between the LI brush fish scenario and the doomsday scenario the EC has been preaching and only now with the better data the models are starting to settle on a track which brings the center into eastern LI.

There was alot of discussion on the main forum about the 00z GFS being questionable. I wonder if the added dropsone data has actually caused more havoc on the models than good. It's not a shocker to me that the 06z GFS came a bit west, even given the fact that its based off of old data, and I wouldn't be suprised to see it jog west again at 12z.

When we are 48 hours out and the system is 300 miles off VA beach heading NW its safe to call game, set, match. But until that point, your only making yourself look foolish by taking every single model run verbatim as if it were a life a death situation. The weeniesm has been something awful. If you can't explain your comment, its probably best to not comment at all. You look at the other sub forums and its loaded with red taggers. Thats not the case here. I wonder why...or not.

Excellent post.

[donsutherland1]

Uncertainty, abosolutely, but I would use caution using the GFDL, its been absolutely awful with this storm.

I fully agree. The GFDL's slight westward shift only indicates that at least some models suggest other options might be available. I'm more interested in seeing how the 12z GFS and Euro come out later today, especially whether they trend farther east or if they come back somewhat west from the 0z and 6z runs. I'll also be interested in seeing if Irene turns more to the north on schedule today or if the turn is somewhat delayed.

[ag3]

12z early guidance dynamic models continue to head east.

Now clustered east of LI and into RI:

[IsentropicLift]

As sad as it is, I think the DGEX may have the right idea here. It's been very consistent showing hit after hit, and its hr 90 location is just east of ACY and then right into the twin forks at hr 102. It would only be about a 10-12 hr event but the rain would be no joke.

[TheTrials]

As sad as it is, I think the DGEX may have the right idea here. It's been very consistent showing hit after hit, and its hr 90 location is just east of ACY and then right into the twin forks at hr 102. It would only be about a 10-12 hr event but the rain would be no joke.

Wow. This model had the storm into Florida keys the other day, then it had it into SC going up into the apps and rotting, and a ton of other solutions in between. It has been anything but consistent and I have never seen it mentioned in any tropical discussion by a serious forecaster.

[Juliancolton]

Wow. This model had the storm into Florida keys the other day, then it had it into SC going up into the apps and rotting, and a ton of other solutions in between. It has been anything but consistent and I have never seen it mentioned in any tropical discussion by a serious forecaster.

Is there any long-range model that didn't go through that swing?

[Metsfan]

06Z early guidance

12Z early guidance

some of those models are slightly west of 6Z

[TheTrials]

Is there any long-range model that didn't go through that swing?

If we are talking 10 days out? No, of course not, but that doesn't mean the DGEX has been consistent like the OP suggested.

If we are talking last three days or so, yes, GFS has been excellent especially outputting four times a day and even the GGEM for whatever reason has been pretty consistent since Sunday.

[TheTrials]

The 12z GGEM yesterday had the eye crossing almost right through NYC and then at 0z its east of Montauk.

So? that is to be expected at 4 days and is a hell of a lot better than the DGEX has been doing . I personally think anything from NYC to eastern LI is well in the game right now, my objection is to calling the dgex conistent and then using it as a model to forecast this storm.

[TheTrials]

There is a big reason people are seeing similarities between the forecasting of winter storms and this cyclone and that is the flow across the norther part of the country which all relates to the nina. Even with nina taking a small break this summer its effects are still being felt. We have had a fast active northern flow back to last winter and it has continued into this summer. Tons of impulses, vorts, pieces of energy, whatever you want to call them, and none of them are well sampled until the are fully within the CONUS obs. As good as the models are, especially the euro, at assimilating data, we have seen time and time again that untilt he energy is all the way on shore within our observation network, we really don't have fulyl know what is spinning out over the ocean or up in canada. That is why 12/27 was a such a head turner, that last vort didn't cross the border until the morning of Xmas eve day and the GFS initialized it on the money and nailed the 12z run that morning.

[tornadojay]

this was posted in one of the main threads.. but I thought I'd repost this HPC discussion here:

...DANGEROUS HURRICANE IRENE TO AFFECT THE NC OUTER BANKS INTO THE

NORTHEAST THIS WEEKEND...

DUE IN PART TO MORE FREQUENT SAMPLING OF THE ENVIRONMENTAL

CONDITIONS SURROUNDING HURRICANE IRENE BY MULTIPLE AIRPLANE

PLATFORMS ALONG WITH CONTINUATION OF SUPPLEMENTAL UPPER AIR RAOBS

ACROSS PARTS OF THE EASTERN CONUS EVERY 6 HOURS...THE MODEL

SOLUTION SPREAD FOR THE TRACK OF IRENE HAS BECOME SMALLER AND

SMALLER...AND IN FACT COULD BE CONSIDERED EXCELLENT FOR THE LONGER

RANGES. ONE OF THE LARGEST REMAINING UNCERTAINTIES IN THE MEDIUM

RANGE PERIOD HOWEVER IS THE EXACT SPEED AND STRENGTH OF A STRONG

SHORTWAVE TROUGH CURRENTLY ENTERING WESTERN CANADA...WHICH IS

EXPECTED TO AMPLIFY OVER ONTARIO/QUEBEC BY DAY 3/SAT AND PICK UP

IRENE. THE 00Z GFS/ECMWF HAVE NEARLY CONVERGED WITH THE DETAILS OF

THIS TROUGH...WITH THE GFS ONLY SLIGHTLY FASTER AND SUPPORTED BY

THE CANADIAN...THUS ACCELERATING IRENE NORTHWARD INTO THE

NORTHEAST/NEW ENGLAND MORE QUICKLY THAN THE ECMWF.

HOWEVER...RUN-TO-RUN VARIABILITY WITH THE MORE UNCERTAIN HIGHER

LATITUDE FLOW IS TO BE EXPECTED...WITH RECENT GFS/ECMWF 4-CYCLE

LAGGED AVERAGE FORECASTS SHOWING 500 MB HEIGHT VARIABILITIES

AVERAGING 50 TO 70 DECAMETERS ACROSS THE UPPER GREAT

LAKES...ENOUGH TO SUPPORT DIFFERING INFLUENCES ON IRENE. BUT FOR

NOW...THE GFS/ECMWF APPEAR TO BE IN RELATIVELY GOOD AGREEMENT WITH

IRENE TO USE NEARLY EQUALLY FOR THE PRELIMINARY PRESSURES/FRONTS

FOR DAYS 3-7. THIS APPROACH WORKS WELL FOR THE WESTERN AND CENTRAL

CONUS AS WELL...AS THE STRONG FLOW ACROSS THE NORTHERN PACIFIC IS

EXPECTED TO SUPPORT CONTINUED STRENGTH AND TIMING DIFFERENCES OF

INDIVIDUAL SHORTWAVE TROUGHS WHICH ARE BEST RESOLVED WITH AN

INTERMEDIATE APPROACH. ONE DIFFERENCE SEEN IN THE LATEST GUIDANCE

IS FOR GREATER AMPLIFICATION OF A SIGNIFICANT SHORTWAVE TROUGH

ACROSS THE PACIFIC NORTHWEST DAYS 6/7...WITH THE ECMWF FASTER IN

EJECTING THE LEADING EDGE OF THE TROUGH OUT OF THE NORTHWEST

COMPARED TO THE GFS...WHICH THEN LEADS TO GROWING DIFFERENCES

DOWNSTREAM. WITH THE 00Z CANADIAN AND THE GLOBAL ENSEMBLE MEANS

PROVIDING GOOD SUPPORT FOR THE GFS SOLUTION...WILL LIKELY ABANDON

THE ECMWF ALTOGETHER STARTING DAY 6...AND INSTEAD BLEND THE 00Z

GFS/GEFS MEAN SOLUTIONS FOR DAYS 6/7.

JAMES/SCHICHTEL

[IsentropicLift]

06Z early guidance

12Z early guidance

some of those models are slightly west of 6Z

The models which shifted west bend the cyclone back to the NNW. They are pretty locked in up till that point. It is nice to see that they didn't trend eastward.

[Stormlover74]

Well obviously this piece from the discussion above seems to be the deciding factor

ONE OF THE LARGEST REMAINING UNCERTAINTIES IN THE MEDIUM

RANGE PERIOD HOWEVER IS THE EXACT SPEED AND STRENGTH OF A STRONG

SHORTWAVE TROUGH CURRENTLY ENTERING WESTERN CANADA...WHICH IS

EXPECTED TO AMPLIFY OVER ONTARIO/QUEBEC BY DAY 3/SAT AND PICK UP

IRENE.

The models which shifted west bend the cyclone back to the NNW. They are pretty locked in up till that point. It is nice to see that they didn't trend eastward.

[Kborne]

The only people that should be "frustrated" here are those that model hug too much and ignore the repeated messages from the NHC regarding track error. The average day 5 track error is 250 miles.

Still, if anyone here is thinking this is a done deal you obviously didn't learn anything from past winter. It's very possible that the exact track lies somewhere between the LI brush fish scenario and the doomsday scenario the EC has been preaching and only now with the better data the models are starting to settle on a track which brings the center into eastern LI.

There was alot of discussion on the main forum about the 00z GFS being questionable. I wonder if the added dropsone data has actually caused more havoc on the models than good. It's not a shocker to me that the 06z GFS came a bit west, even given the fact that its based off of old data, and I wouldn't be suprised to see it jog west again at 12z.

When we are 48 hours out and the system is 300 miles off VA beach heading NE its safe to call game, set, match. But until that point, your only making yourself look foolish by taking every single model run verbatim as if it were a life a death situation. The weeniesm has been something awful. If you can't explain your comment, its probably best to not comment at all. You look at the other sub forums and its loaded with red taggers. Thats not the case here. I wonder why...or not.

When you or the NHC says the 5-day track error is 250 miles, does that mean they averaged the errors (by miles?) they experienced in tracking for all previous hurricanes or is this 250/5day error rate based on statistical errors inherent in the modeling/ or the reliability of the forecasting? Umm, maybe another way of putting this....do they admit that they have identified and then somehow quantified what their error rate is or may be and then factor this into their calculations for mapping out the cone of uncertainty?

[IsentropicLift]

When you or the NHC says the 5-day track error is 250 miles, does that mean they averaged the errors (by miles?) they experienced in tracking for all previous hurricanes or is this 250/5day error rate based on statistical errors inherent in the modeling/ or the reliability of the forecasting? Umm, maybe another way of putting this....do they admit that they have identified and then somehow quantified what their error rate is or may be and then factor this into their calculations for mapping out the cone of uncertainty?

Perhaps you should forward your question to someone that works at the NHC, however I believe they keep verification statistics.

[IsentropicLift]

I got this from the main thread, its an experimental version of the GFS which runs on a different type of initialization scheme, and a few of the mets there say its done well with the tropics in its limited use, any way FWIW its much further west than the regular 06z GFS, link below.

http://www.esrl.noaa.gov/psd/forecasts/gfsenkf/control/

[IsentropicLift]

through hr 60, the 12z NAM looks weaker with the trough over Canada, FWIW

[MJO812]

through hr 60, the 12z NAM looks weaker with the trough over Canada, FWIW

It's also 4mb stronger than it was at 6z at this point.

[Juliancolton]

It's also 4mb stronger than it was at 6z at this point.

Meh, don't worry about the central pressure. We're already 30+ mb deeper than what it initialized at.

[IsentropicLift]

The NAM is coming in slower, by about 6hrs, which could end up in our favor.

[IsentropicLift]

There are significant differences with the S/W riding through the great lakes, on the 12z run its significantly further east, and a tad weaker, which might allow it to sneak by without taking Irene with it.

[IsentropicLift]

The end result is a bit SE of the 06z run, and the disturbance to the east is an interesting feature

[MJO812]

The end result is a bit SE of the 06z run, and the disturbance to the east is an interesting feature

It barely clips Hatteras. Looks like it also might clip LI in the later frames.

[IsentropicLift]

It barely clips Hatteras. Looks like it also might clip LI in the later frames.

I'm not really focusing on its track, I'm more interested in the strenght and position of the upper air features in question, because that is ultimatly what is going to drive the cyclone.

[KEITH L.I]

LOL..the NAM with tropical systems..2 days ago it had it over Miami..please!

[IsentropicLift]

AIRCRAFT FIXES DURING THE PAST 12 HOURS INDICATE THAT IRENE HAS MADE

THE EXPECTED TURN TOWARD THE NORTHWEST...WITH AN INITIAL MOTION OF

305/10. THERE IS NO CHANGE TO THE TRACK FORECAST REASONING AND THE

MODEL GUIDANCE REMAINS IN EXCELLENT AGREEMENT FOR THE FIRST 2-3

DAYS. AFTER THAT TIME...THERE IS SOME QUESTION AS TO WHETHER OR NOT

IRENE CONTINUES ON A NORTH-NORTHEAST HEADING OR TURNS BACK TOWARD

THE NORTH AHEAD OF A MID-LATITUDE TROUGH APPROACHING THE GREAT

LAKES REGION. THE GFDL AND HWRF MODELS REMAIN ALONG THE WEST SIDE

OF THE GUIDANCE ENVELOPE AND SHOW A TRACK OVER OR VERY CLOSE TO THE

MID-ATLANTIC COAST. THE UKMET AND NOGAPS ARE ALONG THE EASTERN SIDE

AND KEEP THE CORE OF THE HURRICANE WELL OFFSHORE. GIVEN THE TYPICAL

MODEL AND OFFICIAL TRACK ERRORS...BOTH SCENARIOS ARE VIABLE OPTIONS

AT THIS TIME...AND USERS ARE ONCE AGAIN REMINDED NOT TO FOCUS ON

SPECIFIC FORECAST POINTS THREE TO FIVE DAYS DOWNSTREAM. THE TVCA

CONSENSUS AND THE EXPERIMENTAL HURRICANE FORECAST IMPROVEMENT

PROJECT CONSENSUS WERE RELATIVELY CLOSE TO THE PREVIOUS NHC

FORECAST. THE UPDATED NHC TRACK HAS BEEN NUDGED EASTWARD AT 96 AND

120 HOURS AND LIES BETWEEN THOSE TWO CONSENSUS AIDS.

I wonder if the NOAGPS bias of being too far east works this time of year?

[IsentropicLift]

Classic

[k***]

so 100 mph right into w long island? niiiiice

http://www.nynjpaweather.com/2011/08/24/the-official-ny-nj-pa-weather-forecast-for-hurricane-irene/