Marathon weather thread

[ariof]

I have a vested interest on the weather on Monday between Hopkinton and BOS, starting a thread here in case anyone else wants to discuss.

BOX says:

Sunday appears to be the transitioning point towards more unsettled weather as a robust cutoff low approaches from the southwest. At this time, it appears that this low will pass well to our northwest over the Great Lakes region , but an associated cold front may bring the first chance for appreciable rain to the region during the late Sunday-early Monday timeframe.

That seems reasonable and has ensemble guidance, although models are now suggesting the fropa might get held back.

The big question is the timing. If the fropa is on Sunday afternoon or evening, it could lead to a mild-but-not-hot, dry, and breezy (with a tailwind!) marathon. (April has the most easterly winds of any month in BOS, which of course the marathon often tries to run into). Slower evolution of the big ULL may allow a backdoor cold front to push in from the coast and keep it cool (the GFS and Canadian have this on Saturday afternoon). If it doesn't, though, a more SWerly flow could push warmer temperatures in, and then there could always be rain (although maybe not 2018-level biblical flood rain) as the 12Z Canadian shows (but rain and cooler temperatures than the GFS). The latest GFS has a slower fropa with warmer, muggier conditions on Monday overwhelming the NE surface flow during the race and the fropa not until Monday evening, while at another extreme 18Z last night it was a faster fropa with strong WSW tailwinds (cough 2011 cough). With Eliud Kipchoge running, that could lead to a course record and perhaps close to the two hour barrier, which has never been done without pacers (although it wouldn't count as a world record because the Boston course is downhill and too straight). 

Anyway, I'm hoping for 52, cloudy, with a W-WSWerly breeze (really WSW shifting WNW right around when I make the turn by the firehouse in Newton) but I'll have to follow the model evolution for the next few days.

[CoastalWx]

57 minutes ago, ariof said:

I have a vested interest on the weather on Monday between Hopkinton and BOS, starting a thread here in case anyone else wants to discuss.

BOX says:

Sunday appears to be the transitioning point towards more unsettled weather as a robust cutoff low approaches from the southwest. At this time, it appears that this low will pass well to our northwest over the Great Lakes region , but an associated cold front may bring the first chance for appreciable rain to the region during the late Sunday-early Monday timeframe.

That seems reasonable and has ensemble guidance, although models are now suggesting the fropa might get held back.

The big question is the timing. If the fropa is on Sunday afternoon or evening, it could lead to a mild-but-not-hot, dry, and breezy (with a tailwind!) marathon. (April has the most easterly winds of any month in BOS, which of course the marathon often tries to run into). Slower evolution of the big ULL may allow a backdoor cold front to push in from the coast and keep it cool (the GFS and Canadian have this on Saturday afternoon). If it doesn't, though, a more SWerly flow could push warmer temperatures in, and then there could always be rain (although maybe not 2018-level biblical flood rain) as the 12Z Canadian shows (but rain and cooler temperatures than the GFS). The latest GFS has a slower fropa with warmer, muggier conditions on Monday overwhelming the NE surface flow during the race and the fropa not until Monday evening, while at another extreme 18Z last night it was a faster fropa with strong WSW tailwinds (cough 2011 cough). With Eliud Kipchoge running, that could lead to a course record and perhaps close to the two hour barrier, which has never been done without pacers (although it wouldn't count as a world record because the Boston course is downhill and too straight). 

Anyway, I'm hoping for 52, cloudy, with a W-WSWerly breeze (really WSW shifting WNW right around when I make the turn by the firehouse in Newton) but I'll have to follow the model evolution for the next few days.

00z Euro looked more ideal with wrly flow. 12z gfs has a SE to more S-SW flow with showers exiting near and just after marathon start time. Still a bit of a ways out.

[Damage In Tolland]

Should dry out nicely by race time. Maybe a light shower early AM but most of the day looks dry and warm. Probably too warm with 65-70

[CoastalWx]

Euro looks like it clears it out in time of race time. It will start cool and probably warm into the 60s by 2pm with a WSW wind.

[Angus]

any chance of onshore wind? - among other problems in '86, I turned the corner at Cleveland Circle to go down Beacon Street and was met with a very cool 40's onshore wind and found myself in an ambulance shivering before I got to Coolidge Corner - it had been very comfortable weather and easy pace for the first 21-22 miles! An intended 2:55 'training run' turned into me lying down on the floor of the green line b/c I felt so horrible! Gosh that was a long time ago! For any runners on the board - I'm laughing at my now broken down self - I wish I could run a single 6:45 mile today!

[Damage In Tolland]

Euro has showers around and .50 thru Monday while GFS mainly is Stein right thru Monday with not much rain anywhere . Odds favor GFS

[adam038]

Weather could be much worse than what it should be tomorrow (low-mid 50s and cloudy with maybe a shower and the annoying wind from the ESE)! ‘18 for me was such a ridiculous run that tomorrow shouldn’t be a big deal. Enjoy it, and good luck! I might even see you out there,
though I wouldn’t know who you are .


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