Feb 28 Severe Storm Threat - Discussion and obs

[Kmlwx]

At least all the salt is getting washed away.

[H2O]

Nice steady rain. Filling in nicely on radar and looks like it will stick around for awhile.

Backbuilding severe?

[H2O]

At least all the salt is getting washed away.

It all going according to plan. There will be a Jan 26 redux in March...book it.

[Avdave]

At least all the salt is getting washed away.

you have salt there? Interesting.

But wow look at this pic on I 40-75 WHOA

[WinterWxLuvr]

you have salt there? Interesting.

But wow look at this pic on I 40-75 WHOA

If that pic is in Knoxville, it pretty much looks like that all the time. Just better vis.

[pazzo83]

Dewpoints in the 70s in southern VA (Emporia, VA is 25/23). Bring that sh*t up this way pls.

[Avdave]

If that pic is in Knoxville, it pretty much looks like that all the time. Just better vis.

Just west of Knoxville indeed it is

[WinterWxLuvr]

Just west of Knoxville indeed it is

It may have gotten better, since they have done quite a bit of road improvement the past few years. That used to be part of what was known as spaghetti junction. Sure did look like some heavy weather in your pic.

[EastCoast NPZ]

Radar returns very misleading today. We've been under "greens" all afternoon until just recently, but not a single drop by my observation has made it to the ground in Middletown since around 1 pm. Haven't been home to check my rain gage yet, but weatherbug (R.E. Aylor) station in Stephens City reports .27 inches, and that station was at .14 before this round of rain moved in before lunchtime. We've gotten very little rain - again.

[Ji]

you have salt there? Interesting.

But wow look at this pic on I 40-75 WHOA

if you squint your eyes hard enough, you can make it look like snow

[Ian]

dont have vorts on maps but it looks maybe a bit south of the nam. maybe in between the nam and the gfs? it actually takes a suface reflection south of us tho it's more an elongated low i guess across the area. i guess maybe we get hit then a bit of a wave goes up the front. definitely a good signal all around for a solid thump of rain. im still not that sure we'll get any massive severe here but it looks like we'll get some decent storms which is a plus for feb either way.

should have stayed meh.

[ThreeRedheads]

if you squint your eyes hard enough, you can make it look like snow

Don't tell that to Master of Disaster.

[Ian]

here comes the front

[BethesdaWX]

Drizzly

[H2O]

here comes the front

Severe Front Warning from LWX?

[Kmlwx]

Severe Front Warning from LWX?

Front Advisory.

[LMolineuxLM1]

It wasnt a total Failure as far as filming, as i got 5 solid lightning bolt shots, spider type. Too-bad i wasnt alerted way earlier other wise i could have had more lightning shots.

[Ellinwood]

Just now having time to get onto the forum... a long trip down to eastern NC proved quite bust-worthy in terms of severe weather. We did experience a nice gust front, which involved areas of zero or near-zero visibility as dust and leaves washed over the back roads... definitely a couple of "hit the brakes!" driving moments in those. I was hoping something could happen in northeast NC where some surface instability was holding during the late afternoon, but the gust front took away the surface instability, and while moderate rain showers developed, nothing explosive/sustainable was able to get going in our area. Had to call off the chase to get back home, otherwise we would have gone into southeast NC and seen some strong thunderstorms. Ended up around Rt. 264 and took that back to I-95 to home.

While it was a bust, I still had a good time. Lots of driving (some of it rather fun on the back roads), got the first chase of the year out of the way to kind of get back into the routine, and had at least some interesting weather.

[Ellinwood]

Also, to bring up the topic of "climo" in regards to the earlier discussion... Ian and I may be looking at it in two different ways. I refer to climo. as strictly "the average," which does not account for individual storm trends or anything of the sort. An example of "accounting for climo" in my view would be something like "the forecast high for next week is 77F, but climo. is 62F so I'll lower the forecast to 74F." To restate, climo. is strictly the long-term mean. I'm speculating that Ian might use climo. to describe "what usually happens" more so than what I have described it as.

[Yeoman]

It wasnt a total Failure as far as filming, as i got 5 solid lightning bolt shots, spider type. Too-bad i wasnt alerted way earlier other wise i could have had more lightning shots.

Those lightning shots are rare indeed.. hopefully you were using an IMAX camera

[LMolineuxLM1]

Those lightning shots are rare indeed.. hopefully you were using an IMAX camera

Dude an IMAX camera would totally rule for lightning shots lol.

[Ian]

Also, to bring up the topic of "climo" in regards to the earlier discussion... Ian and I may be looking at it in two different ways. I refer to climo. as strictly "the average," which does not account for individual storm trends or anything of the sort. An example of "accounting for climo" in my view would be something like "the forecast high for next week is 77F, but climo. is 62F so I'll lower the forecast to 74F." To restate, climo. is strictly the long-term mean. I'm speculating that Ian might use climo. to describe "what usually happens" more so than what I have described it as.

Wow, I never knew what climo was. This is enlightening!

Sure you can't "blame" climo as the main reason in any one event but it's still something to weight. There is a reason we don't expect severe weather outbreaks in Feb--because we almost never have them. That's a function of climo. If you expand your idea out people should never mention La Nina or other things that don't really have that much bearing on individual storms even if they provide a general framework of ideas.

To be sure, yesterday's 'issue' could probably be focused mainly on the cold pool outracing the mid/upper level energy etc. BUT, in May there's a decent shot that cold pool would have been enough to get more significant severe weather around here. It did not yesterday partly because of climo which is not just cooler temperatures, but lower sun energy etc. You can't tell me that a "perfect" low for svr will have the same results in winter as it will in primetime severe season. Not to mention the fact that once you stabilize this time of year there's not much chance of destabilizing again.

[Ellinwood]

Wow, I never knew what climo was. This is enlightening!

Sure you can't "blame" climo as the main reason in any one event but it's still something to weight. There is a reason we don't expect severe weather outbreaks in Feb--because we almost never have them. That's a function of climo. If you expand your idea out people should never mention La Nina or other things that don't really have that much bearing on individual storms even if they provide a general framework of ideas.

To be sure, yesterday's 'issue' could probably be focused mainly on the cold pool outracing the mid/upper level energy etc. BUT, in May there's a decent shot that cold pool would have been enough to get more significant severe weather around here. It did not yesterday partly because of climo which is not just cooler temperatures, but lower sun energy etc. You can't tell me that a "perfect" low for svr will have the same results in winter as it will in primetime severe season. Not to mention the fact that once you stabilize this time of year there's not much chance of destabilizing again.

No storm has ever been dependent on climo. Every storm is dependent on the unique atmospheric conditions in place. February or July... if the surface temp's 70F, the surface temp's 70F. If the CAPE is 500 J/kg, the CAPE is 500 J/kg. Climo doesn't change any variable in any way. Climo can tell you the average amount of times something occurs, but that's it. A storm can be either favored or not favored against the average, but it is never dependent on the average.

[Ian]

No storm has ever been dependent on climo. Every storm is dependent on the unique atmospheric conditions in place. February or July... if the surface temp's 70F, the surface temp's 70F. If the CAPE is 500 J/kg, the CAPE is 500 J/kg. Climo doesn't change any variable in any way. Climo can tell you the average amount of times something occurs, but that's it. A storm can be either favored or not favored against the average, but it is never dependent on the average.

i dont need to have an obscure academic argument about it. there's a reason feb is not considered part of severe weather season here. if you look at the reports its pretty clear places east of the apps and north of the South did poorly as climo would argue.

[Ellinwood]

i dont need to have an obscure academic argument about it. there's a reason feb is not considered part of severe weather season here. if you look at the reports its pretty clear places east of the apps and north of the South did poorly as climo would argue.

I guess I missed that day when the teacher told us "weigh climo into your forecasts but never speak about it to anyone." Climo gives you statistics... that's it. Sure, you have climatologically-favored areas and times, but a forecast and the verifications all pertain to the event at hand. Say you forecast 1' of snow for the mountains and an inch of rain for the valley below... the difference isn't because climo got weighed in, it's because of the weather parameters in the current and forecast atmosphere. I would never say "the strongest storms are expected between 4-6pm because that's the best times according to climo." I would say "the strongest storms are expected between 4-6pm because that is when the maximum diurnal heating and instability are present with this system." Forecasting is all about the variables, not the statistics.

[Ian]

I guess I missed that day when the teacher told us "weigh climo into your forecasts but never speak about it to anyone." Climo gives you statistics... that's it. Sure, you have climatologically-favored areas and times, but a forecast and the verifications all pertain to the event at hand. Say you forecast 1' of snow for the mountains and an inch of rain for the valley below... the difference isn't because climo got weighed in, it's because of the weather parameters in the current and forecast atmosphere. I would never say "the strongest storms are expected between 4-6pm because that's the best times according to climo." I would say "the strongest storms are expected between 4-6pm because that is when the maximum diurnal heating and instability are present with this system." Forecasting is all about the variables, not the statistics.

I don't make a forecast based on past historical statistics. You've basically sidestepped most of what I've said anyway and reframed it as "no one forecasts based on climo alone." Duh? For someone who still has a lot to learn in their field you are very high on yourself.

[Ellinwood]

Let's try something here...

Say I forecasted a high of 75F in an area that has an average high of 50F. Would you tell me to weigh climo. into my forecast and suggest that I lower my forecast so that it's closer to climo?

[mappy]

I guess I missed that day when the teacher told us "weigh climo into your forecasts but never speak about it to anyone." Climo gives you statistics... that's it. Sure, you have climatologically-favored areas and times, but a forecast and the verifications all pertain to the event at hand. Say you forecast 1' of snow for the mountains and an inch of rain for the valley below... the difference isn't because climo got weighed in, it's because of the weather parameters in the current and forecast atmosphere. I would never say "the strongest storms are expected between 4-6pm because that's the best times according to climo." I would say "the strongest storms are expected between 4-6pm because that is when the maximum diurnal heating and instability are present with this system." Forecasting is all about the variables, not the statistics.

Then why use analogs or teleconnections when forecasting? Those are all about statistics and patterns, not variables.

[Ian]

Let's try something here...

Say I forecasted a high of 75F in an area that has a average high of 50F. Would you tell me to weigh climo. into my forecast and suggest that I lower my forecast so that it's closer to climo?

temps are only one part of it. you have differences in jet stream patterns at different times of year, you have less moisture to be tapped, you have less sun power, and on and on and on depending on the time of year. i forecasted it to top 70 yesterday on saturday when guidance was in the low-to-mid 60s so you are again framing this incorrectly as if someone is just blindly following climo with no other rationalization.

[Ellinwood]

temps are only one part of it. you have differences in jet stream patterns at different times of year, you have less moisture to be tapped, you have less sun power, and on and on and on depending on the time of year. i forecasted it to top 70 yesterday on saturday when guidance was in the low-to-mid 60s so you are again framing this incorrectly as if someone is just blindly following climo with no other rationalization.

So let's generalize. If you don't use climo. to forecast a high temperature, do you use climo. to forecast the surface wind speed? the 850mb wind speed? The 500mb dewpoint? Any weather variable?

The point I'm getting to is how does weighing in climo. change the forecast? The reason why this storm took the more climatologically-favored route is because the forecast drastically changed from a late afternoon event to a late morning event. Weighing in climo. would not have legitimately changed the forecast.