5:30pm Thursday: Complete Weekend Storm Update

By -
Flooding

 Here is the forecast precipitation amounts through Christmas Day.
There is a long stripe of 4+inch amounts from Arkansas to near Dayton. As a result, there are flash flood watches out (see below).

Advisories
WSW = winter storm watch. I'm surprised there is a gap in southeast Kansas. The freezing rain advisory covers up a number of areas also under a winter storm watch. The hunter green areas are under a flash flood watch due to the forecast heavy rains for the weekend.

Snow Accumulation

I'm going to show three models. If you average them, you get a pretty good idea of the range of expected amounts.
12Z GFS
18Z GFS
12Z ECMWF
Freezing Rain
12Z GFS
12Z Multi-Model Composite
Freezing rain is a difficult issue for the computer models. My best estimate is that the freezing rain will develop in Oklahoma after 12:01am Saturday morning, including I-35. Keep in mind that Oklahoma is far enough south they do not have enough equipment to quickly respond to deteriorating road conditions. Earlier is better with this storm!  On Saturday, freezing rain and snow will spread over the region with time.

The tornado and severe thunderstorm threat has not changed since this morning's update.

Comments

Post a Comment

Popular posts from this blog

Hilary's Forecast Path Shifts West; Updated 9:20am PDT

By -
Image
The forecast path of the center of Hilary has shifted a bit to the west. This increases the threat to the Southland, especially in terms of flooding.  Rainfall Note the heavy rains are forecast for Los Angeles County. Serious flash flooding may result. Because the forecast path has shifted to the west, that increases the threat of serious flooding in Los Angeles County north into Yosemite and the southern Sierra. It lessens the threat in Utah and western Arizona. While the threat of widespread flooding in Utah and Arizona lessens, note that some thunderstorms with localized heavy rain show up on the map.  In Nevada, the more western path increases the risk of serious flooding around Mt Charleston and into the central part of the state.  Here is the updated  (9am PDT) flash flood risk map. Wind There are already about 40,000 people without power in California, mostly in the center of the state.  The maps above are the peak gusts forecasted with the storm. The highest winds, in general,
Read more

Dangerous Travel Conditions - People Reportedly Stranded

By -
Image
-- Note, more current info available. Scroll up. --- Updated Information as of 8am PDT You are risking your life if you attempt to travel through the purple area.  While the rain has not begun in coastal California, I would urge you to use this time to make any preparations. Power outages have occurred already in southeast California. Here is the latest radar as of 7:55am PDT. As of 6:40am PDT , the radar indicates moderate to heavy rain falling over desert areas of Southern California and far western Arizona (click to enlarge).  Rainfall amounts for the 24 hours ending at 7am PDT show more than two inches have already fallen. There are reports from reliable sources that roads are already washed out and that people are stranded in isolated parts of the desert.  Below is a high-resolution computer model's rainfall forecast from 5am PDT to 11pm PDT Sunday. More than a foot of additional rain is forecast to fall. This will lead to catastrophic flooding.  Here is a map of current watc
Read more

Update on Tornado and Wind Potential; 12 Noon PDT

By -
Image
There was at least one tornado and at least one funnel cloud yesterday.  --- original forecast --- Hilary (the swirly symbol) continues to move NNW paralleling the coast of Baja California, Mexico. The area outlined in red has a significant risk of tornadoe s the rest of the afternoon.  Below is a list of peak wind gusts so far.  Peak winds may increase farther north as the afternoon progresses.  Addition at 12 noon PDT: Sure enough, winds have increased.  Note: If you are in the San Diego area, I recommend not  traveling east on I-8. Heavy rains may cause flash flooding that will involve the highway. 
Read more