- Nov 8, 2018

SNOW PROSPECTS DIM....

The big news in my local area is the fact that that Wednesday nights runs of our weather models have backed off on snow prospects in my area Thursday night and Friday. Up until then most data indicated much of the region was in line for an inch or two of accumulation from two systems combined.

However, the latest output shows most of the snow from system 1 staying southeast and system 2 further southwest. The black-hole effect surfaces again!

As a result, the new and new and refined tracks snowfall forecasts have a much different look than 24 hours ago. Here's the new run of the GFS. It has only 0.1 of snow on Cedar Rapids. Yesterday it had 3.8". You can see the comparison below.

Last night.

Barring any major last minute changes, some light snow or snow showers are still possible Thursday night and parts of Friday. However, most accumulations should be a dusting to 1/2" (maybe some isolated 1" amounts). Here's the latest snowfall forecasts I have as of Wednesday night.

The 3k NAM

The NAM

The GFS (same as above)

The EURO

A closer perspective of the EURO based on Iowa

With minimal (if any) snow cover Saturday morning it looks as though it will be harder to challenge record lows than it looked yesterday. Even so, Saturday will get off to a frigid start with lows in the teens to near 20. The GFS is brutal but I suspect it's several degrees to cold.

Just look at it's wind chills Saturday morning. Fun tailgaiting at the Iowa game with numbers like that!

After a warmer day Sunday around 40, another punch of cold hits Monday and Tuesday. After that, the pattern relaxes and temperatures moderate. That's something I anticipated in a post I made back on October 29th. My rational for the warmer period was the MJO (Madden Julien Oscillation) going into phase 3. For about a week, a more seasonal (if not above normal) brand of temperatures is in the offering for the period November 17-23rd. Then the ridge re-builds and the cold returns by the end of the month. Here's a portion of my post from late October.

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Much of the coming week is projected to remain cold but beyond that some changes should lead to a much warmer period of weather by mid-November. The big tip-off is the MJO (Madden Julien Oscillation) which is projected to move into warmer phases. If you follow the green dots in the phase diagram you can see the progression into phase 2 by November 1st. Top right on the graphic is the temperature correlation. The warmth is building into the upper Midwest.

Come the middle of November, the green dots have advanced into phase 3. Phase 3 in November strongly correlates to above normal temperatures. Look at the extensive warmth top right in the diagram.

The EURO EPS ensembles are catching the potential. Here's the 500mb jet anomalies forecast November 13th. A powerful flow coming off the Pacific....End of excerpt.

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So far the pattern is evolving pretty much on schedule. This is the current 500mb jet stream flow. Look at that big Alaskan ridge driving the cold we are experiencing.

Now look at the 500mb flow forecast the 19th. The ridge has been destroyed allowing the westerlies to flow freely across the nation. At least for a time, the real cold is cut-off from the country.