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WxChallenge 2014-2015


Jurg

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I wish I could say I know what the high will do tomorrow or just plain and simple at this place, but I guess I don't lol. 

67/53/10/0

 

I certainly had a little help from intrahourly magic (read: luck) today. I heavily weighted the Euro for tomorrow (after removing its bias), as it seems to have given the right picture the past couple days. That being said, the Euro would have suggested about the same tomorrow (71-72F) as we had today, but I was too scared to go out on a limb like that.

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City 10 voting ends Friday. Currently, Key West has 78 votes and Laramie, WY has 67 votes...no other contenders have many votes. LAR is at over 7,000 feet in elevation and I personally voted for it. Key West seems like it would be an extremely boring, low error kind of city (barring precip which is dumb luck there).

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That streak of mid-level clouds is really stunting the rise today in Long Beach. However, given that the sea breeze hasn't kicked in yet and should be a function of the temperature, that could just mean a later-than-forecast high (once the mid-level clouds are out of the picture) rather than a lower-than-forecast high.

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That streak of mid-level clouds is really stunting the rise today in Long Beach. However, given that the sea breeze hasn't kicked in yet and should be a function of the temperature, that could just mean a later-than-forecast high (once the mid-level clouds are out of the picture) rather than a lower-than-forecast high.

 

Another thing I've noticed in the past with regards to daily temp values in KLGB is that on days where there is a significant morning marine layer and marginal mixing during the day (like today) the global models are biased towards the warm side (possibly because they don't have the vertical resolution to resolve the shallow marine layer). The MOS disparity between the NAM and GFS was quite evident in this regard. Yesterday's marine layer was close to non-existent, and you can see there is a nice 3-4F temperature lag between yesterday and today despite starting at the same minimum temperature.

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City 10 voting ends Friday. Currently, Key West has 78 votes and Laramie, WY has 67 votes...no other contenders have many votes. LAR is at over 7,000 feet in elevation and I personally voted for it. Key West seems like it would be an extremely boring, low error kind of city (barring precip which is dumb luck there).

 

Yea why in the world is KEYW winning? I also voted for KLAR because I would rather forecast for any city other than Key West, which requires close to no skill for forecasting. 

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64/53/10/0.00

 

Another tricky forecast tomorrow. There is some chance the overnight marine layer never burns off tomorrow and caps the high much lower than the global model guidance is suggesting. For tonight, if the marine layer comes in too quickly, it could cap the temperature in the mid 50's. Dewpoints are higher than yesterday, so we should reach saturation and the development of fog quicker tonight. Even winds are a bit tricky with boundary layer winds ramping up after 00z tomorrow night.. although there is some question as to how quickly this occurs (could be after 06z). 

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64/53/10/0.00

 

Another tricky forecast tomorrow. There is some chance the overnight marine layer never burns off tomorrow and caps the high much lower than the global model guidance is suggesting. For tonight, if the marine layer comes in too quickly, it could cap the temperature in the mid 50's. Dewpoints are higher than yesterday, so we should reach saturation and the development of fog quicker tonight. Even winds are a bit tricky with boundary layer winds ramping up after 00z tomorrow night.. although there is some question as to how quickly this occurs (could be after 06z). 

As long as they ramp up before 8z, then the higher numbers will verify. I went 15. I probably shouldn't trust the NAM with winds as much as I do with Tangy's site.

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My reasoning was higher dew points and the models developing low clouds earlier tonight (along with some mid clouds this evening) keeping lows a few degrees warmer than last night. For tomorrow banked on it taking longer for the morning clouds to clear and the winds not starting off easterly like today due to a slightly stronger pressure gradient capping their high significantly. Not sure if this will all be enough to limit the diurnal spread to 10F or not but felt it was a risk worth taking. On the winds, I forgot that the cutoff was midnight local time. GFS suggests the lower numbers will be OK while the NAM ramps up right before then. Hmm. Give me my high and low and I'll bite the bullet on the winds.

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As long as they ramp up before 8z, then the higher numbers will verify. I went 15. I probably shouldn't trust the NAM with winds as much as I do with Tangy's site.

Exactly.

 

Oh definitely.... it just gives me pause when I see the GFS at the same period putting KLBG in a local boundary layer wind minimum. 

 

wind.gif

 

What's generating the increase in winds is a large synoptic-scale trough digging into the southwest corner of the US. The NAM has a poor track record with synoptic scale entities that are along the boundary of its domain. There is a significant phase speed difference between the GFS and NAM by 06z Saturday with regards to this shortwave, which could make all the difference about when the low-level winds start to ramp up. 

 

namgfs.gif

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Oh definitely.... it just gives me pause when I see the GFS at the same period putting KLBG in a local boundary layer wind minimum. 

 

 

 

What's generating the increase in winds is a large synoptic-scale trough digging into the southwest corner of the US. The NAM has a poor track record with synoptic scale entities that are along the boundary of its domain. There is a significant phase speed difference between the GFS and NAM by 06z Saturday with regards to this shortwave, which could make all the difference about when the low-level winds start to ramp up. 

 

 

All fair points.

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