July 19th-20th: Thunderstorm concerns - hot and humid

July 19th-20th - 2012
Thursday through Friday update


I am in summer mode - that means I try to update every other day or every 2-3 days.  If the weather is active then I will come in and update the forecast as needed.  I will also note an update at the very top of the blog update.

I also add new graphics and tweak the forecast during the day and evening hours - so check back for updates.

For more frequent updates check visit my weather Facebook page - click here and hit like at the top of the page.

 
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Here are my current personal forecast thoughts for far southern Illinois and western Kentucky..

Wednesday night: Partly cloudy - warm and humid - scattered thunderstorms possible
Above normal temperatures.
Lows: in the 70s  |  Normal lows for this time of the year are around 69 degrees.
Wind:  Southerly winds of 5-10 mph
Precipitation probability - 30%  |  Rainfall totals: 0.25"
thunderstorms can and often do produce heavier amounts.
Confidence in this forecast is high 
 
Thursday:  Partly cloudy - hot and humid - thunderstorms possible - some storms may produce hail and high winds.  There are an assortment of heat advisories in effect - check this page for the latest advisories
Above normal temperatures
Highs: mostly in the middle to upper 90s - locally higher temperatures | Normal highs for this time of the year are around 90 degrees.
Wind: Southwest winds at 5-10 mph
Precipitation probability - 60%  |  Rainfall totals:  scattered 0.50"  thunderstorms can and often do produce heavier amounts.
Confidence in this forecast is high

Thursday night: 
Partly cloudy - warm and humid - some thunderstorms possible.
Above normal temperatures
Lows: in the 70s |  Normal lows for this time of the year are around 69 degrees.
Wind:  Southwest winds at 5 mph
Precipitation probability - 40%  |  Rainfall totals: scattered 0.25"
thunderstorms can and often do produce heavier amounts.
Confidence in this forecast is high 

Friday:  Partly cloudy - hot and humid - scattered  thunderstorms - mainly southern areas.  There are an assortment of heat advisories in effect - check this page for the latest advisories
Above normal temperatures
Highs: in the lower to middle 90s |  Normal highs for this time of the year are around 90 degrees.
Wind:  North winds at 5-10 mph
Precipitation probability - 30%  |  Rainfall totals:
scattered 0.50" thunderstorms can and often do produce heavier amounts.
Confidence in this forecast is high


Friday night:  Partly cloudy - warm and humid - isolated thunderstorm - mainly early
Above normal temperatures
Lows: in the lower 70s |  Normal lows for this time of the year are around 69 degrees.
Wind:  North winds at 5 mph
Precipitation probability - 10% - mainly early |  Rainfall totals: scattered 0.25"
thunderstorms can and often do produce heavier amounts.
Confidence in this forecast is medium


 
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Heat - actual air temperatures will be in the 90s and "feel like" temperatures will be 95-105 degrees.  

Hot and humid - typical summer weather for our region.  There are an assortment of heat advisories in effect - check this page for the latest advisories

Thunderstorms will be more likely on Thursday into Friday (Friday for southern counties) as a cold front approaches from the north.  Some of the thunderstorms could produce hail and gusty winds.  There will be a chance for a few severe thunderstorms.  The tornado risk is very low.


I am posting information about the drought on the weather Facebook page - click here and hit like at the top of the page.
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Monitor weather conditions tonight into Friday - if you have outdoor events planned then monitor radars.

An assortment of heat advisories have been issued - heat index values on Thursday into Friday will be in the upper 90s and lower 100s.  Use care.



No wild card in this update
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Updated severe weather chances on Thursday/Friday.

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Forecast for your local town/city - Click Here
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The forecast for severe or extreme weather

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The McCracken County Office of Emergency Management reminds you that owning a NOAA All Hazards Weather Radio is the best way to receive notifications of severe weather watches and warnings.
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Remember that the National Weather Service defines a severe thunderstorm as one that produces 58 mph winds or higher, hail 1" in size or larger, and/or a tornado.  More information with some slides concerning reporting severe weather - click here

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Wednesday:  Isolated severe weather is possible.  No snow or ice.
Wednesday: 
Will there be a risk for non-severe thunderstorms
Yes
 

Wednesday night :  Widespread severe weather is not anticipated.  No snow or ice.
Wednesday night:  Will there be a chance for non-severe thunderstorms? Yes
   

Thursday:  A few severe thunderstorms are possible.  No snow or ice. 
Thursday:  Will there be a risk for non-severe thunderstormsYes
 

Thursday night:  Isolated severe weather is possible.  No snow or ice.
Thursday night: 
Will there be a chance for non-severe thunderstorms? Yes 


Friday:  Isolated severe weather is possible - mainly over southern counties (better chances in Tennessee).  No snow or ice. 
Friday:  Will there be a risk for non-severe thunderstormsYes 

For the most up to date severe weather outlooks - click here.
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Visit the Storm Prediction Center's web-site - click here  


To view storm reports from today and yesterday - click here
 


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Will the Storm Prediction Center issue a tornado or severe thunderstorm watch for southeast Missouri, southern Illinois, or western Kentucky?


Wednesday - No
Thursday - Possible
Thursday night - Possible
Friday - Unlikely
Saturday - No
Sunday - No

To view the official Storm Prediction Center's web-site - click here  Alternative link - click here
 
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To view all watches and warnings in IL -  Click Here
To view all watches and warnings in KY - Click Here
To view all watches and warnings in MO - Click Here
To view all watches and warnings in TN - Click Here
All other states- Click Here

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The links above are interactive and you can move around the United States by simply clicking on the national map - or from the pull down menu where it says regions and US States.
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To view the interactive warning  map - click here.

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You can listen to local emergency services, SKYWARN storm spotters, and more by visiting our scanner feed page - click here


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The Weather Observatory is a strong partner with the National Weather Service - click here to visit your local NWS web-site.  For the most up to date warnings/advisories hit refresh on their page.

 
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This forecast analysis covers far southern Illinois, southeast Missouri, southwest Indiana, western Kentucky, and northwest Tennessee
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HEADLINES:   A cold front will approach our region on Thursday into Friday - the front will approach from the north and will help trigger showers and thunderstorms.  



There will be quite a bit of instability in the region on Thursday and Friday (see maps below) - wind fields will be weak.  Lapse rates will also be weak - we look at lapse rates to get an idea of the hail risk - along with thunderstorm updrafts.  The instability and forcing/lift along the front may help overcome the weak wind fields somewhat - so a few storms could become severe.


The Storm Prediction Center has placed our region in a risk zone for Thursday into Thursday night.  I think this is appropriate - with the front approaching and instability so high.  The main concern will be down burst winds and hail.  Down burst winds can (and over the last few weeks have) produce small pockets of 60-80 mph wind gusts.  Monitor radars on Thursday and Friday.

The most likely time frame for the most intense thunderstorms - where they occur - would be from 11 am through 7 pm on both Thursday and Friday.  A few storms are likely before and after that time, however, they would not be as strong. 

Again - the main concern will be gusty winds, hail, and frequent lightning - heavy downpours, as well. 

The Storm Prediction Center may shift the risk around a little bit - they already have twice.  Bottom line is that a few storms could be severe into Friday afternoon.

Here is the outlook area for Thursday - the orange area is where there will be a few severe storms.  The yellow area is where general thunderstorms are forecast - isolated severe.



Here is the CAPE values for the region on Thursday - remember that CAPE is a measure of instability - readings will be in the 2000-4000+ on Thursday.  That is a LOT of energy.

Click image to see the full size view 


Here is the Paducah sounding - I look at the sounding to see what is going on above us - higher up in the atmosphere.  The sounding for Thursday in Paducah is showing CAPE values above 4000 and lift index values of -4 to -5.  Basically the wind fields appear weak - that is good news.  Weak wind fields will help keep the severe weather risk down.  With that said - there will likely be a few storms that produce hail and high winds on Thursday and perhaps Friday.

Click image to see the full size view  



Also PWAT values will be high on Thursday and Friday - that means there is a LOT of moisture in the atmosphere.  When thunderstorms form they will wring out this moisture producing torrential downpours in some areas.  Meanwhile - neighboring areas can remain bone dry in this type of environment (many of you know that already - some of you have had buckets of rain the last 2 weeks and other areas have barely had any measurable precipitation).  Feast or famine.  

Click image to see the full size view  



Another image showing the moisture on Thursday evening - pooling ahead of the cold front.  See how the PWAT values drop off behind the front.

Click image for the full size view






It will be hot on both Thursday and Friday with highs into the 90s and heat index values in the 95-105 degree range.  It will not feel very comfortable outside.  Dew point levels (moisture in the air) will decrease a bit on Friday night into the weekend.  Although temperatures will still be in the 90s - it won't feel quite as humid.


Let's take a look at the high temperature maps for the upcoming week - the center of the heat dome will be a bit to our west and northwest - that is where the 100-110 degree weather will most likely occur.  




Here is how much precipitation is needed to break the drought



Meteorologists like to compare droughts to historic droughts - one way we measure a drought is the Palmer Drought Severity Index.  I brought up the 1956, 1988, and 2012 drought (June) maps - to compare.  Both 1956 and 1988 were serious drought years.

The first map is June of 1956 - the second map is June of 1988 - the last map is June of this year (2012).




Although we do not know what the rest of July holds - perhaps some chances for scattered thunderstorms - let's take a look at July of 1956 and 1988 - did the drought worsen?  You can see these maps below.  It appears there was some improvement - but overall the drought held on.


There has been some improvement in parts of our region over the last 2 weeks - vs the previous 4-6 weeks.



By the way - I looked up the following November through March of 1956/57 and 1988/1989 to see how the fall/winter shaped up (for precipitation).  This is what the Palmer Drought Index showed.


1988/1989 showed remarkable improvement (we ended up with above normal precipitation and wet ground conditions).  1956/1957 continued with drought conditions.

Dates are above each map.




BUT - if I held off and ran just the February through June of 1957 - our region experienced above normal precipitation (similar to 1988/1989).  If history were to repeat itself then that does offer some hope.  I caution, though, that no two years are ever alike.  


When I run the precipitation above or below normal - this is what I end up with for fall/winter of the 1956 and 1988 drought years.  Fairly significant precipitation.










And for something a little different on the maps - let's take a look at the greenness maps - you can see that a large chunk of the nation has dry vegetation - drought.  Click image for a larger view








We have a TON of new weather maps on the Weather Observatory web-site - these include temperatures, wind speed, dew points, heat index, barometric pressure, predicted rainfall, climate forecast, medium and long range maps, forecasts and more!  Click here 
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We have a number of new radars available on our Weather Observatory web-site!
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We now offer St Louis, Mt Vernon, Evansville, Poplar Bluff, Cape Girardeau, Marion, Paducah, Hopkinsville, and Dyersburg Interactive City Radars.  We also have the two regional radars and now offer you three GR Earth radars.

Click here for our radar page - WEATHER RADARS---
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We also have a new interactive radar - you can view that radar by clicking here.


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Want to learn more about how to use our radars?  I made a how to video with more information
Click here - http://www.youtube.com/watch?v=bfLa0hI3adU
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Let's check out the how much rain is forecast to fall over the next 72 hours (5 days).  This map gives you a general broad brushed idea of what can be expected.  Remember the scale is at the top of the map.
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If you would like to view the most up to date 24, 48, 72, and 120 hour precipitation forecast maps then click here.


Remember that thunderstorms can produce locally heavy rainfall totals that will exceed the totals shown on this map. 





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You can also now view the probability of X amount of rain (you pick the value on the web-site) in a six hour period of time.  Those maps can be viewed here.  
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You can view drought maps on the Weather Observatory web-site by clicking here.


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Current conditions - including temperatures, apparent temperatures, heat index, wind chill, wind, pressure, humidity, dew points, and more - click here

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You can view the upcoming days high temperature and low temperature forecasts by clicking here - choose the day - click on your state to zoom in 
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To view recent records that have been broken - click here

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Remember that as a general policy, in the long range outlook, I try not to mention severe thunderstorms more than 72 hours in advance (unless the signal is so overwhelmingly convincing that it warrants a mention).  I will mention thunderstorm risks and I will give as many details as possible.  Also remember you can view the long range severe weather outlooks by visiting the Storm Prediction Center's web-site - click here

 
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DROUGHT INFORMATION - CLICK HERE 


Here are the latest 6-10 day temperature and 8-14 day temperature outlooks - see the date stamps at the top of each image


Here is the latest July through September temperature outlook





Seasonal outlooks can be viewed on the web-site - click here



If you are a weather enthusiast then I recommend listening to WeatherBrains each week!  For a more in-depth look at what is happening in meteorology.




Now is a GREAT time to buy a NOAA All Hazards Weather Radio.  Better to have one before storms strike than to be without one during an event.  I recommend the Midland Model 300 NOAA All Hazards Weather Radio - that is what I use here at my house!
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Meteorologist Beau Dodson
McCracken County Office of Emergency Management
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Beau Dodson Weather - Facebook
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To view all watches and warnings in Illinois - Click Here
To view all watches and warnings in Kentucky - Click Here
To view all watches and warnings in Missouri - Click Here
To view all watches and warnings in Tennessee - Click Here
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All other states- Click Here
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For the latest watches and warnings please visit your local National Weather Service Office web-site
http://www.weather.gov/organization.php
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Remember most of the maps on the blog can be viewed on Weather Observatory Web-Site
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