High Temperatures today and Tueday.

Very warm today in many places but no extremes.

Dew points. 70+ on this scale makes it feel uncomfortable(sticky air)!  Humid over the southern (and Mid Atlantic Coast today) parts of the country...........pooling moisture into S.Plains providing high precipitable water to use for heavy rains.

Heat and high humidity COMBINED. Feels like temperature. Feeling sultry in the south. Dry air N.Plains.

Highs days 3-7.

Heat moves around............without the intense heat featured at times in some locations recently(West).

So temps are fairly close to normal in many places.

How do these days 3-7 temperatures compare to average at this time of year?  We are now almost 4 weeks past the climatological time of year when temperatures are the hottest.

Above average along the Canadian border and West but not extreme.

High temperature departures:

Low Temperature Departures:

Weather system from East Coast back to Texas(where it's much more active).  

https://weather.com/maps/currentusweather

Here is the latest radar image:

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

Satellite picture. 

Rains the past 24 hours.    Dry  in the Cornbelt.....that will change big time!

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"

Missouri  to S.Plains still in bad shape......the map below will look much different later this week. Much more rain is on the way to make an even bigger dent in the long lived drought.

Below are rains compared to average of the last 7, 14, 30 and 60 days. Usually not updated for previous day until late the next day.

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

Drought Monitor. This product is updated every Thursday. Drought will be shrinking.

            http://droughtmonitor.unl.edu/Maps/CompareTwoWeeks.aspx    

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:  What's left of the record smashing heat that WAS in the  Pacific Northwest a few days ago, then the  N.Plains is last seen in Southeast Canada!  

In 5+ days:

Heat is moving around. Still hottest West......spews east  to Plains/Upper Midwest briefly.  Anamolies not as extreme.

In 10+ days   Warmest West again!!!! Heat moving around...... ..most place close to average.

Day 15 Warmest West. Massive uncertainty elsewhere.

Latest 0z run of the Canadian model ensembles..........for late week 2.  Majority have some troughing dipping down into the Upper Midwest to Northeast. Much uncertainty.....especially on where the heat ridge(which will be there) will be located. Preferred place for ridge is the Rockies...........but it could be anywhere. Upper level trough off the West Coast???

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

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

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 Aug 24, 2018 00 UTC

Below are some of the 0z GFS individual ensembles at the end of 2 weeks. Alot of disagreement with some still placing the Upper level heat ridge farther east.  

The end of week,  6Z GFS ensemble average shows an upper level ridge building in  Western Canada.........actually, today its even stronger into E.Alaska and far Northwest Canada than it was yesterday......if this happens, it WILL be a precursor to downstream troughing and a jet stream aimed toward the Midwest/Northeast with cooling. 

Then, the question will be: How deep and far south is the upper level trough downstream?

Image URL: http://mag.ncep.noaa.gov/data/gefs-mean-sprd/06/gefs-mean-sprd_namer_360_500_vort_ht.gif

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

Carries thru with some of the week 2 changes taking place on that last GFS ensemble product described above. Heat ridge continues to build back west again.........cooling downstream Plains/Midwest to East Coast most pronounced in week 4.................when skill is very low.

Precip below:

Last 12z GFS operational model is still pretty dry for the northern 1/3rd of the Cornbelt vs other models in the week 1 period.

Tons of rain for at least the southern 1/2....up to around Des Moines IA.

1 week rains below.

Forecast Hour:  168
Image URL: http://mag.ncep.noaa.gov/data/gfs/12/namer/precip_ptot/gfs_namer_168_precip_ptot.gif

Total 2 week rains below......getting pretty hefty to possibly too much in some areas(S.Plains to Southwest Cornbelt)?

There has been a strong heavy rain signal in this same area for several model runs in a row now.

What's interesting is this is over the same area that had the severe, long lasting drought until recently. Most of this rain will probably be seen as beneficial.

Forecast Hour:  384
Image URL: http://mag.ncep.noaa.gov/data/gfs/12/namer/precip_ptot/gfs_namer_384_precip_ptot.gif

 It rebuilds the  ridge but farther northwest........extremely impressive positive anamoly off the SW Coast of Canada. Powerful jet over the top of that as the jet stream buckles and downstream energy is aimed towards the N.Plains to Midwest.

Another heat ridge builds in the SE US.

Late week 2 maps below:

gfs_namer_360_200_wnd_ht	gfs_namer_360_500_vort_ht
gfs_namer_360_1000_500_thick	gfs_namer_360_850_temp_ht

The just updated 12z Canadian operational model has a very potent system in the North, late week 1 with massive rains up there into the start of week 2..

Maps like these below, for the next 10 days are extraordinarily rare for August (which is usually the driest Summer month) because of the amounts of widespread rain over the next 8 days. Wow!

The Canadian model does have a wet bias but we have a very wet 8 days ahead!

Images created on Mon 13 Aug at 17:04Z

The just updated 12z Canadian ensembles for late week 2 are different for late week 2 than the GFS products.

1. Not nearly as pronounced with the upper level ridge along the West Coast of North America..........in fact, it features a noteworthy upper level trough of the West Coast of the US with many having an impressive cut off low there.

384h GZ 500 forecast valid on Aug 29, 2018 12 UTC

Forecasts for the control (GEM 0) and the 20 ensemble members (global model not available)

Extreme weather days 3-7. Heavy rain S.Plains to Southwest Cornbelt. Also Eastern Great Lakes. 

More heat in the Pac Northwest.

Extended looks cool and wet for the Midwest. Warm along the Coasts.

6-10 day Temperature Probability

Precipitation Probability

8-14 day Temperature Probability

Precipitation Probability