Thursday, June 18, 2015

Forecasts for far in the future: that's all, folks

I was going to do another forecast for long-range to super long-range, but a) I got busy doing other stuff, and b) I think I proved my point.

So now, let's focus on what the times and regions of general agreement are, as they will determine when we leave and what our initial target is.

At this point, it's a toss-up as to whether we leave Saturday or Sunday.  It appears a slumping cold front will stall somewhere in the central plains states and then rebound north as a warm front.  How far south this front goes before it stalls will dictate our first move.  If it looks like it'll go too far, i.e. away from the good upper flow, we'll hang out for a bit.  If it should stall beneath the good flow, then we'll leave earlier.

What is also in focus, now, is the general idea that there will be instability and shear juxtaposed, and they will likely come together for a good chunk of the trip, if not all of it.  Right now I don't foresee us chasing in Canada, but that could always change.  It looks like we will most likely be spending a good amount of time in the Dakotas, Nebraska, Wyoming, Montana and maybe Colorado.  (If you think this sounds like a lot, ask me sometime about the time we decided to go for a walk in the woods.)

I'm cautiously optimistic.

Tuesday, June 16, 2015

Is today the day we get consistency?  Let's see.

Day 1 (June 20):
GFS: SD/NE/IA border
ECMWF: Eastern NE/western IA
GDPS: Eastern SD
CFSv2: NE/northeast CO

Day 2 (June 21):
GFS: Eastern NE/western IA
GEFS: Eastern CO/Nebraska/IA
GDPS: Western KS
CFSv2: Eastern CO

Day 3 (June 22):
GFS: Western SD to eastern NE
GEFS: SD/northern NE
ECMWF: Western NE to eastern CO
GDPS: Western Dakotas
CFSv2: Eastern MT to NW KS

Day 4 (June 23):
GFS: Western ND to northeast NE
GEFS: SD/eastern ND
ECMWF: Eastern WY
GDPS: Eastern Dakotas
CFSv2: Western SD to northeast KS

Day 5 (June 24):
GFS: SW Nebraska to central WI
GEFS: SD/eastern ND/MN/IA
ECMWF: Eastern WY
CFSv2: Western NE to central IN

Day 6 (June 25):
GFS: Eastern WY to northern IL
GEFS: Eastern WY to northern IL
ECMWF: Western NE
GDPS: Southern SD
CFSv2: Southern IA to western NY (hahaha)

Day 7 (June 26):
GFS: SE MT to northern IL
GEFS: Eastern WY to northern IL
CFSv2: Southern SK to western SD

So the day 1 model runs are pointing rather consistently now to a pretty good show in the eastern Dakotas to eastern Nebraska.  After that, though, there's pretty much no consistency.  This is more or less a hallmark of a zonal flow--little wavelets will cause most of the weather.  If there were a big trough out west or, much worse, a big trough out east, then the models would be pretty consistent in depicting that--the models have a tendency to be good in the more amplified situations and not so good in the less amplified ones.

This is pretty encouraging, I think, because a zonal flow means that moisture won't be a problem, but it'll just be the timing of the flow/waves/lift.  The problem with that, though, is that it may involve quite a bit of driving from one day to the next.  (Although not necessarily.)

Monday, June 15, 2015

As we get closer and closer to the trip, we should likely see more consistency both run-to-run and amongst different runs.  Let's see if that's the case yet.

Day 1 (June 20):
GFS: Southern MN, IA and southern WI
GEFS: Eastern Dakotas to southern WI
ECMWF: Western IA
GDPS: Western IA
CFSv2: Eastern WY to northeast CO to southern NE

Day 2 (June 21):
GFS: KS/NE border
ECMWF: Central AB or eastern CO
GDPS: Eastern CO
CFSv2: Central MT to northwest MO

Day 3 (June 22):
GFS: Western Dakotas to southeast NE
GEFS: Dakotas
ECMWF: Central SD or central NE
GDPS: Western NE or western KS
CFSv2: NE WY to northern IA

Day 4 (June 23):
GFS: Southern NE to lower Michigan
GEFS: Dakotas or MN
ECMWF: Southeast IA to northern IL
GDPS: Central NE
CFSv2: Northern IL to lower MI

Day 5 (June 24):
GFS: Western Dakotas or southern MB
GEFS: Dakotas
ECMWF: Eastern MT to northeast CO
GDPS: Dakotas
CFSv2: Eastern WY or northern IL

Day 6 (June 25):
GFS: Western IA to northeast MN
GEFS: Eastern Dakotas
CFSv2: Central MT

Day 7 (June 26):
GFS: Southern NE

Well, we're not at consistency yet.  Model-to-model is still really all over the place.  And that makes sense, as the upper features that'll be affecting our trip are right now being (poorly) picked up by satellites over the Pacific ocean.  Funny enough, though, I had a look at the day before our trip starts--that day being Friday, June 19.  And lookie, lookie, the models are in really good agreement on that day, that there should be a really good show in South Dakota.

So perhaps with tomorrow's model runs we'll start to get a clearer picture on things.  It sure looks to me, though, that we'll likely have storms every day of the trip--it's just going to be a matter of whether the storms will be influenced by good flow.  And you'd be surprised what even modest flow can do with good instability.  As a very well-known and -respected forecaster is wont to say, big CAPE kicks big ass.

Sunday, June 14, 2015

Storm chase forecast, issued Sunday June 14, 2015

So here goes.  I haven't yet looked at the guidance, so you (sort of) will be looking at it (or hearing about it) along with me.  I expect fewer changes in the nearer term, although I expect some, but in the longer term (i.e. toward the end of the trip) I expect there to be huge differences.

So let's get to it.

Day 1 (June 20):
GFS: Eastern NE/western IA
ECMWF: Western KS/Eastern CO
GDPS: Western NE/NE CO
CFSv2: OK/TX panhandles to SW KS

Day 2:
GFS: Eastern KS or SW SD
GEFS: Northern NE/SW SD
GDPS: Eastern CO/western KS
CFSv2: Eastern NM

Day 3:
ECMWF: Southern AB to eastern MT
GDPS: Eastern CO/western KS
CFSv2: Eastern CO

Day 4:
GEFS: SE MT/Dakotas
ECMWF: The Dakotas, Nebraska and eastern WY (huge area)
GDPS: Western KS
CFSv2: Western NE/western SD

Day 5:
GEFS: Eastern Dakotas
CFSv2: Central NE to central ND

Day 6:
GFS: Eastern CO to eastern KS
GEFS: Dakotas
CFSv2: Central MT to southwest IA

Day 7:
GFS: SW SD to eastern NE
GEFS: Eastern Dakotas/NE
CFSv2: North-central MT or western SD to central IA

Some changes are pretty huge, and some show some run-to-run consistency.  What this exercise is already showing, I think, is that the consensus this far out is pretty poor.  Suffice to say, however, that we will likely be looking at ample instability over a good portion of the chaseable regions; it'll just be a matter of whether or not we can get flow overtop that.

Saturday, June 13, 2015

We're baaaaack, and just in time for storm chase season, too

The U of M trip is getting ready to set out and, as has been custom in the previous years, I thought I'd do a long-range forecast for chasing, mostly to illustrate how futile it really is.  I'll base the forecasts on the models cited under each date, those being the GDPS (formerly GEM-Global), GFS, GEFS, ECMWF and (for laughs) CFSv2.

Day 1 (June 20):
GFS: Eastern CO to northern KS
GEFS: Eastern CO to eastern SD
ECMWF: Eastern CO to eastern NE
GDPS: Eastern CO to southeastern NE
CFSv2: OK/TX panhandles

Day 2:
GFS: Black Hills of SD to Denver, CO
GEFS: Nebraska, eastern WY and NE CO
ECMWF: Eastern NE, western NE/southeast WY
GDPS: Eastern CO/southeastern WY/western NE
CFSv2: Western Dakotas to NE CO

Day 3:
GFS: Central Dakotas (!)
GEFS: Dakotas
ECMWF: Eastern WY/MT
GDPS: Iowa (sucks)
CFSv2: Central Dakotas

Beyond day 3 of this forecast, a bunch of models drop off because they only go out that far into the future.  As we get closer to go time, we will have more models to look at every day.

Day 4:
GFS: Southern MN to northern IA
GEFS: Eastern Dakotas
CFSv2: Southern AB or SW SD

Day 5:
GFS: Eastern CO to western KS
GEFS: Eastern Dakotas
CFSv2: Alberta or Dakotas to Nebraska

Day 6:
GFS: Eastern CO to most of KS
GEFS: Eastern Dakotas
CFSv2: SE SK to eastern Dakotas

Day 7:
GFS: Western SK or NE CO
GEFS: Eastern Dakotas to western WI
CFSv2: Eastern Dakotas

So there you have it.  For reference, have a look at previous forecasts for previous years to see how they panned out.

In short, up until about 3 days before we go, there will be a) significant variation amongst the different models, and b) significant variation from one run to another of the same model.  So living and dying by the models is a great way to give yourself an ulcer.

I'm really looking forward to meeting you students and seeing my old friends.  I left Manitoba late last summer and I've only been back for one brief visit.  

I'll try to do this more or less every day until we leave, but because of numerous personal commitments until that point, I can't guarantee it.  But here's hoping!

Oh, by the way: I'll repeat this later again, but if your friends and family want to follow along with us, we have a pretty neat page up and running with our location on a map and selected tweets from a few of us.  The URL is: