Alton, Illinois Weather Conditions

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Current Conditions

  • 68°
  • Clear
  • Wind: South 6 mph
  • Humidity: 83%
  • Visibility: 10.0 miles
  • Dew Point: 63°
  • Pressure: 30.04 in. +

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Next 12 Hours

10  am
1  pm
4  pm
7  pm
10  pm
Mostly Cloudy
Mostly Cloudy
Overcast
Overcast
Chance of a Thunderstorm
Chance of T-storms
Chance of a Thunderstorm
Chance of T-storms
Chance of a Thunderstorm
Chance of T-storms
73°
77°
82°
75°
72°
Forecast data from the National Digital Forecast Database.

5 Day Forecast

  • Saturday
  • Chance of a Thunderstorm
  • High: 84 °
  • Low: 64 °
  • Chance of a Thunderstorm
  • Sunday
  • Partly Cloudy
  • High: 72 °
  • Low: 50 °
  • Partly Cloudy
  • Monday
  • Partly Cloudy
  • High: 68 °
  • Low: 45 °
  • Partly Cloudy
  • Tuesday
  • Partly Cloudy
  • High: 70 °
  • Low: 48 °
  • Partly Cloudy
  • Wednesday
  • Partly Cloudy
  • High: 75 °
  • Low: 50 °
  • Partly Cloudy

Forecast for Alton, Illinois

Updated: 10:00 AM CDT on September 20, 2014

  • Saturday

    Mostly cloudy in the morning, then overcast with a chance of a thunderstorm and a chance of rain. Fog early. High of 84F. Winds from the SW at 5 to 10 mph. Chance of rain 20%.

  • Saturday Night

    Partly cloudy with a chance of a thunderstorm and a chance of rain in the evening, then overcast with a chance of a thunderstorm and a chance of rain. Low of 64F. Winds from the WSW at 5 to 10 mph. Chance of rain 50% with rainfall amounts near 0.2 in. possible.

  • Sunday

    Partly cloudy. Fog early. High of 72F. Winds from the NW at 10 to 15 mph.

  • Sunday Night

    Partly cloudy. Fog overnight. Low of 50F. Winds from the NNW at 5 to 10 mph.

  • Monday

    Clear in the morning, then partly cloudy. High of 68F. Winds from the NNE at 5 to 10 mph.

  • Monday Night

    Partly cloudy in the evening, then clear. Low of 45F. Winds from the East at 5 to 10 mph.

  • Tuesday

    Overcast. Fog early. High of 70F. Winds less than 5 mph.

  • Tuesday Night

    Partly cloudy. Low of 48F. Winds from the ESE at 5 to 10 mph.

  • Wednesday

    Mostly cloudy. High of 75F. Winds from the ESE at 5 to 10 mph.

  • Wednesday Night

    Clear. Low of 50F. Winds from the SE at 5 to 10 mph.

  • Thursday

    Mostly cloudy. High of 75F. Winds from the SE at 5 to 10 mph.

  • Thursday Night

    Partly cloudy. Low of 54F. Winds from the SE at 5 to 10 mph.

  • Friday

    Clear. High of 77F. Winds from the SE at 5 to 10 mph.

  • Friday Night

    Clear. Low of 54F. Winds from the ESE at 5 to 10 mph.

  • Saturday

    Mostly cloudy. High of 77F. Winds less than 5 mph.

  • Saturday Night

    Partly cloudy. Fog overnight. Low of 55F. Winds less than 5 mph.

  • Sunday

    Partly cloudy. High of 77F. Winds less than 5 mph.

  • Sunday Night

    Clear. Fog overnight. Low of 57F. Winds less than 5 mph.

  • Monday

    Clear. High of 75F. Winds less than 5 mph.

  • Monday Night

    Clear. Fog overnight. Low of 59F. Winds less than 5 mph.

  • Tuesday

    Partly cloudy with a chance of a thunderstorm. High of 75F. Winds less than 5 mph. Chance of rain 50% with rainfall amounts near 0.2 in. possible.

  • Tuesday Night

    Clear. Fog overnight. Low of 59F. Winds less than 5 mph.

Personal Weather Stations

Personal Weather Stations [Add your weather station!]

Location: MesoWest ALTON IL US UPR, Alton, IL

Updated: 6:30 AM CDT

Temperature: 65 °F Dew Point: - Humidity: - Wind: Calm Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Alton - Christian Hill Area, Alton, IL

Updated: 8:55 AM CDT

Temperature: 69.5 °F Dew Point: 63 °F Humidity: 79% Wind: NW at 2.0 mph Pressure: 30.00 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: MesoWest US-67 @ Clark Bridge IL US ILDOT, Alton, IL

Updated: 8:25 AM CDT

Temperature: 66 °F Dew Point: 66 °F Humidity: 99% Wind: SE at 1 mph Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Alton - Rock Gate Estates, Alton, IL

Updated: 8:56 AM CDT

Temperature: 66.4 °F Dew Point: 65 °F Humidity: 94% Wind: Calm Pressure: 30.05 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Milton Area - Oscar, Alton, IL

Updated: 8:48 AM CDT

Temperature: 67.5 °F Dew Point: 64 °F Humidity: 88% Wind: Calm Pressure: 29.98 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Brecht Ln, Godfrey, IL

Updated: 8:45 AM CDT

Temperature: 72.9 °F Dew Point: 68 °F Humidity: 85% Wind: Calm Pressure: 29.90 in Hourly Precipitation: - Heat Index: 72 °F Graphs

Location: WEST ALTON, West Alton, MO

Updated: 8:50 AM CDT

Temperature: 63.5 °F Dew Point: - Humidity: - Wind: North at - Pressure: - Hourly Precipitation: - Heat Index: - Graphs

Location: Godfrey River Aire Subdivision, Godfrey, IL

Updated: 8:56 AM CDT

Temperature: 67.3 °F Dew Point: 64 °F Humidity: 88% Wind: ESE at 1.0 mph Pressure: 29.98 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Rosewood Heights, East Alton, IL

Updated: 8:56 AM CDT

Temperature: 67.4 °F Dew Point: 62 °F Humidity: 84% Wind: SSE at 1.0 mph Pressure: 29.95 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Foster Township, Alton, IL

Updated: 8:54 AM CDT

Temperature: 64.2 °F Dew Point: 63 °F Humidity: 97% Wind: SW at 2.7 mph Pressure: 30.00 in Hourly Precipitation: - Heat Index: - Graphs

Location: Timber Ridge, Godfrey, IL

Updated: 8:55 AM CDT

Temperature: 66.1 °F Dew Point: 65 °F Humidity: 97% Wind: South at 2.0 mph Pressure: 30.02 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: MesoWest NAMOK2 IL US UPR, Granite City, IL

Updated: 7:50 AM CDT

Temperature: 67 °F Dew Point: - Humidity: - Wind: Calm Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: MesoWest NAMOK1 IL US UPR, Granite City, IL

Updated: 6:35 AM CDT

Temperature: 65 °F Dew Point: - Humidity: - Wind: Calm Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Grand Ave, Edwardsville, IL

Updated: 8:56 AM CDT

Temperature: 73.9 °F Dew Point: 66 °F Humidity: 75% Wind: Calm Pressure: 30.00 in Hourly Precipitation: 0.00 in Heat Index: 75 °F Graphs

Location: Riverwood Place, Florissant, MO

Updated: 8:56 AM CDT

Temperature: 70.4 °F Dew Point: 66 °F Humidity: 87% Wind: Calm Pressure: 30.03 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Nickel Plate Trail, Edwardsville, IL

Updated: 8:55 AM CDT

Temperature: 67.6 °F Dew Point: 65 °F Humidity: 91% Wind: Calm Pressure: 30.01 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: EAST GRANITE, Granite City, IL

Updated: 8:51 AM CDT

Temperature: 67.5 °F Dew Point: 62 °F Humidity: 84% Wind: Calm Pressure: 29.99 in Hourly Precipitation: - Heat Index: - Graphs

Location: MesoWest SHPMAN IL US UPR, Shipman, IL

Updated: 7:55 AM CDT

Temperature: 64 °F Dew Point: - Humidity: - Wind: Calm Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Piasa, Piasa, IL

Updated: 8:44 AM CDT

Temperature: 67.9 °F Dew Point: 64 °F Humidity: 87% Wind: SW at 9.0 mph Pressure: 29.96 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Barbarotto Compound, Maryville, IL

Updated: 8:56 AM CDT

Temperature: 68.9 °F Dew Point: 65 °F Humidity: 87% Wind: SSE at 7.0 mph Pressure: 29.95 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: 1 Mile South of St. Louis Lambert Airport, Woodson Terrace, MO

Updated: 8:56 AM CDT

Temperature: 69.3 °F Dew Point: 66 °F Humidity: 89% Wind: SW at 1.0 mph Pressure: 30.04 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Rolling Meadows Dr, Maryville, IL

Updated: 8:56 AM CDT

Temperature: 69.1 °F Dew Point: 63 °F Humidity: 82% Wind: SSE at 2.5 mph Pressure: 29.35 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Polestar Boating Center, St. Charles, MO

Updated: 8:57 AM CDT

Temperature: 67.5 °F Dew Point: 64 °F Humidity: 89% Wind: WSW at 1.0 mph Pressure: 30.08 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: St. Ann, MO, St. Ann, MO

Updated: 8:43 AM CDT

Temperature: 71.4 °F Dew Point: 66 °F Humidity: 83% Wind: SSE at 2.7 mph Pressure: 29.96 in Hourly Precipitation: - Heat Index: 71 °F Graphs

Location: Liberty Place, Troy, IL

Updated: 8:51 AM CDT

Temperature: 69.2 °F Dew Point: 65 °F Humidity: 85% Wind: SW at 5.0 mph Pressure: 29.41 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: Branch Street, St. Louis, MO

Updated: 8:51 AM CDT

Temperature: 66.7 °F Dew Point: - Humidity: 78% Wind: North at - Pressure: 29.56 in Hourly Precipitation: - Heat Index: - Graphs

Location: Hamel, IL 55/140, Worden, IL

Updated: 8:56 AM CDT

Temperature: 70.0 °F Dew Point: 64 °F Humidity: 82% Wind: South at 4.7 mph Pressure: 28.55 in Hourly Precipitation: 0.00 in Heat Index: - Graphs

Location: BLAIR STREET, St. Louis, MO

Updated: 8:50 AM CDT

Temperature: 65.8 °F Dew Point: - Humidity: 85% Wind: North at - Pressure: 29.49 in Hourly Precipitation: - Heat Index: - Graphs

Location: MesoWest I -55/64/70 @ Poplar St Bridge IL US ILDOT, Fairmont City, IL

Updated: 8:25 AM CDT

Temperature: 65 °F Dew Point: 62 °F Humidity: 90% Wind: SSW at 7 mph Pressure: - Hourly Precipitation: 0.00 in Heat Index: - Graphs

MSN Maps of:

Temp: Dew Point: Humidity Wind Pressure Hr Precip -

NWS Forecaster Discussion




Area forecast discussion...updated aviation 
National Weather Service St Louis MO 
654 am CDT Sat Sep 20 2014 


Short term: (through tonight) 
issued at 214 am CDT Sat Sep 20 2014 


This prd will focus on approaching cold front that currently 
stretches from cntrl Minnesota SW across far northwest Iowa...NE and eventually NE 
Colorado. This feature is being driven by a significant short wave 
dropping thru the grt lks. This bndry will slowly work south thru 
the day. Guidance has slowed this feature over the past 24 hrs. It 
is not expected to reach our NE MO counties until closer to 
midnight and not clear southeast MO until early Sunday mrng. There is some 
potential of convection breaking out ahead of the front this aftn 
as a vort Max and weakness in the sfc pressure field/wind shift may 
be enough to initiate at least some isld convection. Even if 
shras/tstms are able to dvlp this aftn...the better precip 
coverage will be this evng thru the overnight hrs. Storm Prediction Center has areas 
north of i70 under a slight risk of severe wx. This looks reasonable 
based on temps in the mid/upper 80s with dps in the upper 60s to 
near 70 producing sb cape values in excess of 3000 j/kg and mu 
cape in excess of 2000 j/kg and 0-6km shear values of 30-45kts. 
There is also a significant mid and upper level jet Max nosing 
into Iowa and nthrn Illinois from the Dakotas. So, any storms that can 
get going have the potential to become svr, with large hail and 
damaging winds being the primary threats. I think that there is a 
relatively small window for svr convection from late aftn thru mid 
evng before the bndry layer cools enough to limit buoyancy. The 
NAM indicates significant levels of cape, around 1000 j/kg, to exist 
thru the night. This solution is an outlier with the remainder of 
the guidance indicating cape to decrease significantly after 6z. 
So, expect convection to continue south thru the night weakening 
in the process. 


2% 


Long term: (sunday through friday) 
issued at 214 am CDT Sat Sep 20 2014 


The cold front should clear the sthrn County Warning Area around 12z with any 
lingering precip mvng out shortly thereafter. A secondary short 
wave will pass just to the NE of the area Sunday. Due to the first 
impulse clearing out the moisture, this second shortwave is not 
expected to have much impact on the sensible wx other than maybe 
some increased cloudiness across our Illinois counties. Beyond this 
feature, high pressure will be in control for the remainder of the 
week as an upper level ridge builds across the plains providing 
mostly clear skies and dry conditions. Temps will start the first 
half of the week in the low/mid 70s and should moderate to near 80 
by Friday. One caveat to this scenario is a closed low off the California 
coast that is fcst to come onshore this wknd and tries to undercut 
the ridge but gets absorbed into the mean flow as the week 
progresses. I don't expect this feature to have a significant 
effect on the sensible wx attm...but that could change as the week 
moves forward. 


2% 


&& 


Aviation: (for the 12z tafs through 12z Sunday morning) 
issued at 630 am CDT Sat Sep 20 2014 


Focus continues to be thunderstorms and rain chances thru tonight. Fog will quickly 
dissipate this morning with sunrise. Ongoing thunderstorms and rain over srn Iowa will 
continue to dissipate this morning. Storms are expected to impact 
terminals this afternoon and into the evening ahead of an 
approaching cdfnt. These storms may be strong to severe with 
damaging wind gusts as the main threat. Can not rule out scattered thunderstorms and rain 
around/just before 18z today. However, scattered nature of storms and 
uncertainty is too great to mention in taf attm. Otherwise, winds 
will become nwly behind the fnt. 


Specifics for kstl: main threat for thunderstorms and rain will be this eve ahead of 
approaching cdfnt. However, can not rule out a scattered thunderstorms and rain impacting 
the terminal around 18z today. Storms this evening are no longer 
expected to be severe, but wind gusts to around 45 kts may be 
possible. Winds will become nwly behind the fnt late in the 
period. 


&& 


Lsx watches/warnings/advisories: 
MO...none. 
Illinois...none. 
&& 


$$ 


Weather forecast office lsx 



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