November 9/10 Midnight update:
Post date: Nov 10, 2013 5:44:05 AM
Minor updates to the overnight forecast were made with the main focus looking at the possible minor snowfall event during late Monday into Tuesday. Temperatures will be dropping into the mid 30's before warming up slightly into the upper 40's compared to a high of 60 on Saturday afternoon. A very strong high pressure is continuing to build and sink southward with its central pressure around North Dakota by Monday evening. As this high pressure sinks southward, it will be forming a moisture deprived band of precipitation. Vorticity values look minimal and precipitable water values around a half inch. Models are indicating a somewhat thin band of snowfall possibly mixed with some rain in the onset. Looking at the temperatures aloft, it is possible we may encounter the dentritic growth zone which would allow some minor accumulation over mostly grassy and elevated surfaces, but because temperatures during the onset of the precipitation Monday evening will be in the mid to upper 30's to even around 40, it is possible to see some drizzle or light rain mixed in with the snow. As the precip continues I anticipate the colder air aloft to sink further down to the surface during the overnight hours which would allow greater chances of snow to stick. Current thinking in regards to snow amounts would be a trace to a few tenths of an inch. I do not see anything greater than a half inch at this point.
After the snow Monday night, this high pressure will continue to build in providing some very nice unseasonably cold air for a few days as the high pressure continues to push southward but as it does so it will weaken. Multiple days up until the weekend can see mostly sunny skies with relatively cool nights with temperatures dropping down into the 30's.
By the weekend, the high pressure will push to the east of us allowing a southerly flow to develop bringing high temperatures into the 50's. Some models such as the GFS and ECMWF(a.k.a. the answer) do show a possible system diving down into southwestern Canada and then scooping up into Hudson Bay into Saturday and Sunday which would aid in more of this southerly flow.
Besides Monday evening, the rest of the week appears to remain dry.