Boston 2019 Weather Thread

Six days to go

weather.com: hi 52 / lo 42 / 60% chance of rain / wind NW 10-20 mph

accuweather.com: hi 51 / lo 36 / 67% chance of rain / wind NNE 10-20 mph

Ensemble forecasts have a pretty high range still:

https://weather.us/forecast/4930956-boston/ensemble/euro/precipitation

jimcantore wrote:

One of the key items that ensemble forecasts provide.

link to ensemble please

Convexity wrote:

Six days to go

weather.com: hi 52 / lo 42 / 60% chance of rain / wind NW 10-20 mph

accuweather.com: hi 51 / lo 36 / 67% chance of rain / wind NNE 10-20 mph

Ensemble forecasts have a pretty high range still:

https://weather.us/forecast/4930956-boston/ensemble/euro/precipitation

This is cool!

The global euro ensemble is showing a range [10th-90th percentiles] 1.4 inches to 3.2 inches of rain along the course on Monday at 8am and a mean of 2.2 inches. The numbers are similar for 2pm. The 10/90 percentile range for temperature is huge, 40F to 61F, with a mean of 48F at 8am and 52F at 2pm. I don't see anything on wind other than wind gusts, but not wind direction which is really the key.

tldr, it will likely be wet with moderate temperatures with the wind being unknown.

I'll take cool and rainy and pray for favorable wind.

This is cool!

The global euro ensemble is showing a range [10th-90th percentiles] 1.4 inches to 3.2 inches of rain along the course on Monday at 8am and a mean of 2.2 inches. The numbers are similar for 2pm. The 10/90 percentile range for temperature is huge, 40F to 61F, with a mean of 48F at 8am and 52F at 2pm. I don't see anything on wind other than wind gusts, but not wind direction which is really the key.

tldr, it will likely be wet with moderate temperatures with the wind being unknown.[/quote]

You sure you're reading those rainfall spreads right? I'm not quite sure how to interpret that chart but it seems like some kind of cumulative weekly total. 1.4 inches would be moderate to heavy rainfall all day, 3.2 inches would be a downpour. The forecasts I'm looking at are calling for a 50%-65% chance of rain with an average of less than half an inch.

Sorry, messed up the quotation there. Anyway it does look like a cumulative total and they may have revised it down since you posted. So between 2:00 AM Monday and 2:00 Tuesday the 10% is 0.4", the 90% is 1.0", and the mean is 0.8" with most of the rain in the morning and early afternoon. So probably light to moderate rain but not the epic downpours of 2018 of 2007.

all wet wrote:

Sorry, messed up the quotation there. Anyway it does look like a cumulative total and they may have revised it down since you posted. So between 2:00 AM Monday and 2:00 Tuesday the 10% is 0.4", the 90% is 1.0", and the mean is 0.8" with most of the rain in the morning and early afternoon. So probably light to moderate rain but not the epic downpours of 2018 of 2007.

oh you're right. the chart wasnt labeled but its obviously a cumulative. From 2am to 2pm its showing an cumulative rain of 0.4". That's not bad. The 90th percentile goes form 0.8" to 1.5" over that same time frame so a total of 0.7". I believe the US ensemble is not cumluative. That's showing a mean of 0.2" to 0.4" at 11am and 2pm. With a max of 0.9" at 2pm.

Five days to go

weather.com: hi 54 / lo 45 / 60% chance of rain / wind NE 10-20mph

accuweather.com: hi 61 / lo 45 / 67% chance of rain / wind W 13-21mph

Winds are shifting a little, so that's pretty up in the air still (no pun intended).

Ensemble forecast still showing a pretty wide band:

42-62 degrees 10th-90th percentiles at 11am

24-39mph wind gusts 10th-90th percentiles at 11am

https://weather.us/forecast/4930956-boston/ensemble/euro/temperature

looking wet, but the temps could be anywhere... here's the NWS forecast discussion

Sunday and Monday...

A moisture laden southern stream low pressure system will lift

northeast into the vicinity of southern New England. Details though

remain uncertain, but wet weather weather appears to be in the cards

late Sun into Mon and the potential for a period of heavy rain.

Temperatures remain quite uncertain over this time frame. If the

main low or a developing secondary low cuts to our south, a cold

soaking rain will occur with temperatures mainly in the upper 30s

and 40s Sunday night into Monday. On the flip side of the coin, a

more inland track may result in much milder conditions with the

potential for temperatures to rise into the 60s for a time in the

warm sector.

In a nutshell, track/timing and intensity of this low pressure

system will determine the amount of rain along with temperatures

across the region. Regardless, high confidence in wet weather

sometime late Sun into Mon with the potential for a period of heavy

rain.

https://forecast.weather.gov/product.php?site=BOX&issuedby=BOX&product=AFD&format=CI&version=1&glossary=1&highlight=off

Still so much time for it to change!

What I'm most concerned about is the wind.

H0peful wrote:

Still so much time for it to change!

What I'm most concerned about is the wind.

Well, bro. It ain't looking good. 8-10 mph mainly head wind.

H0peless wrote:

H0peful wrote:

Still so much time for it to change!

What I'm most concerned about is the wind.

Well, bro. It ain't looking good. 8-10 mph mainly head wind.

http://www.findmymarathon.com/weather/boston-marathon-weather.php

8-10 mph isn't terrible. Last year was what, a 25mph headwind?

H0peful wrote:

Still so much time for it to change!

What I'm most concerned about is the wind.

Agreed about the wind.

The good thing is that it's shifted each of the past 3 days, so it's not set in stone.

Anything out of the N-S-W, I'll be a happy camper. It's E that is less than desirable.

What we are seeing goes to show how rare 2011 was. Basically if the low pressure moves below boston we get cool weather and headwind. If it moves above Boston we get warm weather and tailwind. Really difficult to get cool weather and tailwind. Personally, I'll take my chances with the wind rather than risk a 60 plus degree day.

I have a pair of Red Sox tickets for Friday's game for someone in town for the marathon. I will sell them at face value.

Four days to go...

weather.com: hi 58 / lo 47 / 90% chance of rain / wind E shifting S 10-20mph

accuweather.com: hi 60 / lo 47 / 76% chance of rain / wind SSW 13-20mph

Ensemble pretty much in same range as yesterday:

43-60 degrees 10th-90th percentiles at 11am

24-41mph wind gusts 10th-90th percentiles at 11am

https://weather.us/forecast/4930956-boston/ensemble/euro/temperature

The wind sucks, but that the fact that it will be at least 10 degrees warmer than last year should stave off a lot of the hypothermia concerns. I think at these temperatures, you can avoid the windbreaker (those who didn't have one last year generally regretted it, except for those who are naturally acclimated / run hot).

Easy Peasy wrote:

The wind sucks, but that the fact that it will be at least 10 degrees warmer than last year should stave off a lot of the hypothermia concerns. I think at these temperatures, you can avoid the windbreaker (those who didn't have one last year generally regretted it, except for those who are naturally acclimated / run hot).

The wind kills more time than any other element.

Nothing increases effort level like a headwind.

H0peful wrote:

H0peless wrote:

Well, bro. It ain't looking good. 8-10 mph mainly head wind.

http://www.findmymarathon.com/weather/boston-marathon-weather.php

8-10 mph isn't terrible. Last year was what, a 25mph headwind?

Ugh. Now forecast looks a lot warmer. At least no headwind until making the turn.