Excessive Rain threat

Increasing very early next week.

Current Day 1 Forecast

Day 1 Threat Area in Text Format  

Current Day 2 Forecast

Day 3 forecast below

Severe Storm Risk.

Pretty quiet. 

https://www.spc.noaa.gov/products/outlook/

Current Day 1 Outlook
Current Day 2 Outlook
Current Day 3 Outlook
Current Day 4-8 Outlook

High Temperatures today and Saturday.

Chilly North, especially N.Plains/Upper Midwest ......stays very warm far southeast.  

Highs days 3-7.

 Very chilly to cold air in the North.  Warmth battles back. The warmth wins for southern 2/3rds for awhile.   

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

 Above average Southern 2/3rds. Well below normal N.Plains.

Low Temperature Departures:

Surface features for the same 3-7 day period:

Front between very warm and cold air across the Midwest for several days..........finally gets kicked south later in this period  by a strong system and trailing cold front.

Dew points.

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

Higher dew points are in the southeast.

Much, MUCH drier air than last week in the northern 1/2.

Current Surface features:

Stalled front Midatlantic to South, Reinforcing cold front Midwest.

https://weather.com/maps/currentusweather

Latest radar loop.

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

Satellite picture.

2 huge cloud masses.

Rains the past 24 hours

2 big areas with a gap in between.

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!  

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 Friday.  There will be a deep upper level low/trough in Central Canada with widespread cold extending south into the northern parts of the US during week 2. How strong will the upper level ridging be in NW. Canada? Will Pacific flow try to cut this off????  Numerous members have the upper level ridge in the far Southeast remaining a force to be reckoned with.  
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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 13, 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:  Cold air in the north! Still warm far Southeast.

In 5+ days:

Heat ridge builds back in from the southeast for a few days. Cold recedes temporarily to the northwest.

In 10+ days:

 Still the same battle between warm Southeast and cold farther northwest.

Day 15:  Extreme anomalies weaken. Pacific flow making a presence, ushering the cold eastward? Pattern morphs?

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

Extreme Upper level ridging Alaska to West Coast has been a constant theme for the past 10 days as well as the downstream cold air in Canada that gets into the Northern US. Todays run shows  this continuing to hold together, with renewed cold in Canada.

Precip is drier today.

Heating degree days(from cold weather) are replacing cooling degree days(from hot weather) as being the most important as we get into October.

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

Precip below:

National Weather Service 6-10 day, 8-14 day outlooks.

The forecasts below are similar to the last 10 days or so.  Cold Northern Plains, very warm Southeast and very  wet everywhere. In fact, exeptionally wet. 

There has been some guidance that makes a case for the  flow becoming more zonal later in week 2......west to east. This would moderate the extremes in temperature. The jet stream along the US/Canadian border would still likely to be pretty strong, so the pattern may be fairly active and wet.

However, the 12z guidance on Friday is trying to strengthen the upper level ridge in the far Southeast a bit late week 2, which would effect the configuration of the jet stream upstream/approaching it............induce a more southwest to northeast component to upper level winds approaching the upper level ridge.

This upper level "heat ridge" has been such a long lived feature in September, very often exceeding forecasts for its strength and tenacity. Keeping that in mind, my forecast will keep it going well into week 2...........even as it gradually shrinks and shifts farther and farther southeast.

Temperature Probability

Precipitation Probability

the 8-14 day outlooks ArchivesAnalogsLines-Only FormatGIS Data

Temperature Probability

Precipitation Probability

The NWS releases a week 3-4 forecast on Fridays.

This one is cold in the midsection and wet from the S.Plains across the Ohio River Valley to MidAtlantic, with increasing probabilities as you go south. The extended time frame equates to a low skill forecasting product.............but here it is.

The long lived heat ridge is still having an impact in the far Southeast. 

Temperature Probability	Precipitation Probability (Experimental)

Extreme weather days 3-7

That widespread threat for heavy rain in the Midwest is for the entire period. After one of our wettest September's ever, we will have one of our wettest starts to October!

Extreme weather days 8-14:

More heavy rain events are likely into the 2nd week of October but shifting southward with time as upper level ridge in the Southeast weakens and also allows the cold to sink south into the N.Plains.