Excessive Rain threat

Really goes up later this week into early next week

Current Day 1 Forecast

Day 1 Threat Area in Text Format  

Current Day 2 Forecast

Day 3 forecast below

High Temperatures today and Thursday.

The heat surges north, then recedes!

Highs days 3-7.

 Very chilly to cold air N.Plains/N.Rockies.  Very warm to near record warmth south/east of that.

How do these days 3-7 temperatures compare to average at this time of year?

 Tale of 2 extremely opposite temperature regimes! Above average eastern 1/2(near records). Well below normal N.Plains/Rockies.....near record cold.

A slight shift in the location of the boundary between these extreme air masses will greatly change the temp forecast for areas close to the boundary.

Low Temperature Departures:

Surface features for the same 3-7 day period:

Front between very warm and cold air during the entire period..................goes back and forth..........it's location will vary with every forecast update. 

Potent storm/wave development possible along the front.

Dew points.

 70+ on this scale makes it feel uncomfortable(sticky air)!  

Higher dew points are returning with southerly flow.

Current Surface features:

High pressure has moved east. Southerly winds on the backside are ushering in very warm/humid air.  The boundary between that very warm/humid air and cooler air to the north will be going back and forth.

https://weather.com/maps/currentusweather

Latest radar loop.

http://www.nws.noaa.gov/radar_tab.php

Satellite picture.

Rains the past 24 hours

Upper Midwest to Great Lakes to Northeast.

You can go to this link to see rain totals from recent time periods:

https://water.weather.gov/precip/

Go to precipitation, then scroll down to pick a time frame. Hit states to get the borders to see locations better. Under products, you can hit "observed" or "Percent of normal"

Soil moisture anomaly:

Too wet in a large area from one of our wettest Septembers in history......but it will get even wetter!

The 2nd map gets updated once a week.

Rains compared to average for the last 7, 14, 30 and 60 days. 

Usually not updated for previous day until late the next day.

Note how wet it's been over the past 60 days over eastern 2/3rds of the country!

https://www.atmos.illinois.edu/~snodgrss/Ag_Wx.html

The top map is the Canadian ensemble average, the maps below are the individual members that make up the average

End of week 2....................0Z ensembles from Wednesday. Cooler for the Midwest/East from yesterday on some members, with the northern stream dominating, while other members try to build the heat ridge in the Southeast again.
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Each member is like the parent, Canadian model operational model.......with a slight tweek/variation in parameters. Since we know the equations to represent the physics of the atmosphere in the models are not perfect, its useful to vary some of the equations that are uncertain(can make a difference) to see if it effects the outcome and how.

The average of all these variations(ensembles) often yields a better tool for forecasting. It's always more consistent. The individual operational model, like each individual ensemble member can vary greatly from run to run.........and represent an extreme end of the spectrum at times. The ensemble average of all the members, because it averages the extremes.............from opposite ends of the spectrum............changes much less from run to run.

360h GZ 500 forecast valid on Oct 18, 2018 00 UTC

Temperature Anomalies from GFS ensembles(fairly reliable product) going out 2 weeks. These maps show the Northern Hemisphere. The map of the US is front center. Look for the state borders in  white.

Today:  Southern edge of cold air in Canada in the northern Plains! Very warm air to the south, boundary will be on the move the next 24 hours.

In 5+ days:

Heat ridge builds back in from the southeast for a few days. Cold pools in Canada to the N.Plains. Where will the boundary be in this time frame????

In 10+ days:

 Still "looks like" the same battle between warm Southeast and cold farther northwest.......but possibly a change coming after this. Note much less magnitude in the anomalies.

Day 15:  Extreme anomalies gone. The lions share of cold has been ushered eastward into Eastern Canada. Today, we see continue to see  some prounced upper level ridge building along the West Coast and troughing in the East. This would mean warm/West, cool/East could be the new pattern. However, the long lived upper level ridge in the Southeast may not be dead.

The low skill, longer range CFS model for weeks 3-4.

Another big change today. Strong upper level ridging Western Canada to Alaska...........builds eastward, with mild/dry Pacific air masses. Most of the cold is pretty far north in Canada. 

Potential  to dry out in the Midwest.

Heating degree days(from cold weather) are replacing cooling degree days(from hot weather) in October.

Check in tomorrow to read something different............."low skill" (-:

Precip below: