Utah Lake 4-hour rule?

[kenonstott]

There is always plenty of argument over wind theories and I would hate to make a living predicting wind. Still, when I sailed Utah Lake MM19 a lot in my previous life (the 1st time Rush dried up) I came up with a rule that seems to generally hold true. MM19 doesn’t seem to go nuclear until about 4 hours before the front hits. Up until 4 hours before the front comes through the northerly thermal gradient seems to push back hard against the south wind, either killing it or severely retarding it. If you think about your epic sessions, how many times did the front come through while you were sailing (the wind went west and darn near stranded you). Some of my best MM19 sessions include the remark “moved to Rocky to get another sesh on small gear”. Yesterday held to the rule as the wind started flirting with +20 a little before 10pm and the front came through about 2am.

Grantsville is another lake with a lot of northerly push in the afternoon. It was the prediction of the front coming in after midnight that kept me at Grantsville instead of heading to MM19. Fighting the bugs and heat for 2.5 hours between the morning and afternoon sessions was an ordeal but the reward was 20 to +30 mph winds. Grantsville’s rules seem to be the morning thermal session will be best the day before the front comes through (do the south winds blowing all night blow out the thermal?) and forget sailing a south between 12:00 and 2:00 (the North push kills south wind just like at Rush Lake during the famous noon lull). Yesterday, John came at about 3:00 and the north wind had moved all the way into Grantsville. It was a close call that the north didn’t overcome the south. That brings up another Grantsville rule, waiting for the south to come back after the noon lull is a crapshoot. 2 of the 4 days I have waited for the south to come back it went north and stayed there. That really makes you love all those bugs that have loaded into your vehicle while you were waiting for nothing. Grantsville has turned into bug city and the lake is dropping very fast so all of this may be moot shortly.

[Craig Goudie]

That's pretty much the way I'd represent it, except that if the front
has jetstream enhancement at UL (we're talking South wind here),
the wind will be stronger, and start earlier by a couple hours.

I wouldn't bet on the afternoon resurge at Grantsville on a South,
unless the prevailing winds are forecast at 20-30 or better, there's
a awfully large mountain blocking the South wind.

It would appear from Manni's post that MM19 was pretty good
from about 5:30 on, so 4 hours might be a little conservative

.02,

-Craig

There is always plenty of argument over wind theories and I would hate to make a living predicting wind. Still, when I sailed Utah Lake MM19 a lot in my previous life (the 1st time Rush dried up) I came up with a rule that seems to generally hold true. MM19 doesn’t seem to go nuclear until about 4 hours before the front hits. Up until 4 hours before the front comes through the northerly thermal gradient seems to push back hard against the south wind, either killing it or severely retarding it. If you think about your epic sessions, how many times did the front come through while you were sailing (the wind went west and darn near stranded you). Some of my best MM19 sessions include the remark “moved to Rocky to get another sesh on small gear”. Yesterday held to the rule as the wind started flirting with +20 a little before 10pm and the front came through about 2am.

Grantsville is another lake with a lot of northerly push in the afternoon. It was the prediction of the front coming in after midnight that kept me at Grantsville instead of heading to MM19. Fighting the bugs and heat for 2.5 hours between the morning and afternoon sessions was an ordeal but the reward was 20 to +30 mph winds. Grantsville’s rules seem to be the morning thermal session will be best the day before the front comes through (do the south winds blowing all night blow out the thermal?) and forget sailing a south between 12:00 and 2:00 (the North push kills south wind just like at Rush Lake during the famous noon lull). Yesterday, John came at about 3:00 and the north wind had moved all the way into Grantsville. It was a close call that the north didn’t overcome the south. That brings up another Grantsville rule, waiting for the south to come back after the noon lull is a crapshoot. 2 of the 4 days I have waited for the south to come back it went north and stayed there. That really makes you love all those bugs that have loaded into your vehicle while you were waiting for nothing. Grantsville has turned into bug city and the lake is dropping very fast so all of this may be moot shortly.