By: Stephen McCoy
Conditions have far from improved for the TOTAL 24 Hours of Spa. Starting with tomorrow, temperatures are likely in the low 90's °F, low 30's °C with the latest model runs in a good amount of agreement. There could be a bit of variance in the temperature, as was seen today where a maximum temperature of 98 °F, 37 °C was recorded at Spa (my forecasted high temperature from Tuesday was 95 °F, 35 °C). The cold front mentioned in the previous forecasts is expected to pass through the region in the late afternoon to evening on Friday, bringing with it a slight chance of isolated showers. Model guidance suggests that most of the on-track sessions should be run as normal, though the Super Pole session could be impacted by showers in the area should they occur early enough; recent runs indicate showers starting around or just before 8:00 pm local time. Northwesterly surface winds behind the front will cause temperatures to drop during the morning with a low temperature on Saturday in the mid 60's °F, upper teen's °C.
I mentioned in the previous forecasts that if the front were to stall, the chances of precipitation would likely go up, which, according to the recent model runs, will turn out to be the case. A surface low pressure system to the southeast over southern Germany (extending into northern Italy) will cause winds from the southeast to push back against the cold front, stalling it to the east of the track. The cooler winds from the northwest will undercut the warmer air from the southeasterly winds, causing widespread precipitation throughout the day. Depending on timing/intensity of precipitation some of the sessions during the day may be delayed or even red-flagged. Showers will continue into the evening and overnight with chances tapering off somewhat into Sunday. However, chances for scattered showers are still possible, though timing is less concrete. Fog may be possible during the morning as air temperatures approach dew point temperatures. The surface to 500 millibar bulk shear indicates that the aforementioned low pressure system will move to the northeast during Sunday, allowing the front to continue to track eastward. This will allow winds to shift fully to the west to northwest, bringing the coolest temperatures of the weekend to the region.
I mentioned in the previous forecasts that if the front were to stall, the chances of precipitation would likely go up, which, according to the recent model runs, will turn out to be the case. A surface low pressure system to the southeast over southern Germany (extending into northern Italy) will cause winds from the southeast to push back against the cold front, stalling it to the east of the track. The cooler winds from the northwest will undercut the warmer air from the southeasterly winds, causing widespread precipitation throughout the day. Depending on timing/intensity of precipitation some of the sessions during the day may be delayed or even red-flagged. Showers will continue into the evening and overnight with chances tapering off somewhat into Sunday. However, chances for scattered showers are still possible, though timing is less concrete. Fog may be possible during the morning as air temperatures approach dew point temperatures. The surface to 500 millibar bulk shear indicates that the aforementioned low pressure system will move to the northeast during Sunday, allowing the front to continue to track eastward. This will allow winds to shift fully to the west to northwest, bringing the coolest temperatures of the weekend to the region.
