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McHenry County, IL Weather and Climate Synopsis

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Weather Summary For Central And Southeast Illinois
National Weather Service Lincoln IL
424 AM CST Wed Dec 13 2017

Mostly clear skies across the region allowed temperatures to drop
back to the 20s for overnight lows.

Calm winds will give way to breezy southerly winds once again, as
another clipper system moves through the Midwest. This will 
spread snow across the Great Lakes, while the chance for rain 
showers exists across Illinois and western Indiana. Temperatures
will increase again today, but behind the front, colder air will
return for Thursday. As the week continues, clipper systems will 
progress over the Great Lakes, bringing the chance for snowfall 
through the end of this week and into the weekend.

High temperatures today, will range from the mid 20s across 
central Wisconsin and northeast Indiana, to the upper 50s across 
southwest Missouri. Lows Wednesday night will return to the teens
across northern Illinois and Indiana, while dropping to the upper
20s along the Ohio River Valley.

National Ag. Weather Outlook, International Ag. Weather Summary
Current Surface Map, [2nd Source TWC]

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Regional Hourly Observations For MCHENRY County
Issued at 600 AM CST WED DEC 13 2017

NORTHEAST ILLINOIS
  
CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
CHICAGO-OHARE  CLOUDY    25  12  58 S12       29.68F WCI  14          
6HR MIN TEMP:  22; 6HR MAX TEMP:  25;                                

CHICAGO-MIDWAY CLOUDY    26  11  52 S12       29.70F WCI  16          
6HR MIN TEMP:  22; 6HR MAX TEMP:  26;                                

AURORA         CLOUDY    25  14  63 SE13      29.66F WCI  14          
6HR MIN TEMP:  20; 6HR MAX TEMP:  25;                                

LANSING*       CLOUDY    25  13  60 S14       29.74F WCI  13          
JOLIET*        CLOUDY    28  12  52 S8        29.70F WCI  20          
WAUKEGAN       CLOUDY    24  11  57 S14       29.65F WCI  12          
6HR MIN TEMP:  19; 6HR MAX TEMP:  24;                                

DUPAGE AIRPORT CLOUDY    25  13  60 S14       29.66F WCI  13          
6HR MIN TEMP:  20; 6HR MAX TEMP:  25;                                

KANKAKEE*      CLOUDY    26  10  49 S9        29.74F WCI  17          
WHEELING       CLOUDY    25  13  60 S12       29.69F WCI  14          
6HR MIN TEMP:  22; 6HR MAX TEMP:  25;                                

MORRIS*        CLOUDY    26  11  52 S13       29.68F WCI  15          
ROMEOVILLE*    CLOUDY    25  12  58 S10       29.69F WCI  15          
NORTHERLY ISL    N/A     24  10  55 S8          N/A  WCI  15          

Current Temperatures, Dewpoint Map, RH, Wind, Regional Obs, Surface 4-Panel
Meteograms : Springfield , Peoria , Quad City , Chicago (O'Hare) , Rockford


Current Agricultural Weather Conditions in Illinois
Based on observations at 600am CST, Wednesday December 13, 2017

Across Illinois...temperatures are near 25 degrees north, near 27 degrees central, and near 26 degrees south. Current sky conditions are cloudy north, cloudy central, and partly cloudy south. In the north, relative humidity is near 68%, and the dew point is near 16 degrees. In the central part of the state, relative humidity is near 53%, and the dew point is near 12 degrees. In the south, relative humidity is near 65%, and the dew point is near 16 degrees. Winds are from the south at 18 mph north, where conditions are not favorable for spraying due to strong winds. The wind chill is near 11 degrees north. Winds are from the south at 12 mph central, where conditions are favorable for spraying. The wind chill is near 17 degrees central. Winds are from the southwest at 9 mph south, where conditions are favorable for spraying. The wind chill is near 17 degrees south. The livestock cold stress index is in the no stress category north, no stress category central, and no stress category south. Based on current available observations, the highest temperature is 32 degrees at Quincy and Moline. The lowest temperature is 21 degrees at Robinson and Lawrenceville.


Current NOWCAST not available:
Nowcasts are not issued routinely during fair weather. Only when
precipitation or other significant weather is occuring in this county will these
forecasts be issued. Currently, there is no short term forecast in effect.

US Radar, All NWS Radars (In near-real time),Livestock Heat Stress Index (LSI), Wind Chill Map
Hazardous Weather Outlook For MCHENRY County,IL

409 AM CST Wed Dec 13 2017 /509 AM EST Wed Dec 13 2017/

 DAY ONE  Today and Tonight.

WEATHER HAZARDS EXPECTED:

  Limited Non Thunderstorm Wind Risk.
  Elevated Snow Risk.

DISCUSSION:

Another clipper system will track through the region today, 
bringing the potential for light precipitation. With the surface 
low passing across far northeast Illinois this afternoon, the best 
chance of accumulating snow will generally be north of the
Wisconsin border. Light accumulations, generally less than an
inch, will be possible mainly across the northern Suburbs of
Chicago. Colder and blustery weather will arrive tonight as the
low pulls away to the east. Gusty northerly winds to 35 mph may
turn northeast for a time, which will likely produce some lake
effect snow showers across far northeast Illinois this evening,
which will move east into Indiana overnight. Minor accumulations
will be possible, perhaps an inch or so in Illinois, and 2 to 4
inches in Indiana. Higher amounts are not out of the question if
the lake snow band remains over one location for a period of time. 

 DAYS TWO THROUGH SEVEN  Thursday through Tuesday.

Thursday  
  Elevated Snow Risk.
Friday  
  Limited Snow Risk.

DISCUSSION:

Lake effect snow will linger over northwest Indiana Thursday
morning. Confidence is low in exactly where the band will be, but
the band will shift east through the morning. The snow will likely
impact the Thursday morning commute in northwest Indiana.

 SPOTTER INFORMATION STATEMENT  

Spotter activation will not be necessary through tonight.

NWS Severe Weather Map , Convective Outlook


7-Day Forecast For MCHENRY County, IL
359 AM CST Wed Dec 13 2017

TODAY
Cloudy with a 40 percent chance of light snow. Highs in the mid 30s. South winds 10 to 20 mph in the morning shifting to the west in the afternoon. Gusts up to 35 mph.

TONIGHT
Cloudy with a 30 percent chance of light snow showers in the evening, then partly cloudy after midnight. Lows 13 to 17. North winds 10 to 20 mph. Gusts up to 35 mph in the evening.

THURSDAY
Mostly sunny in the morning then becoming partly sunny. Highs in the upper 20s. Northwest winds 5 to 10 mph.

THURSDAY NIGHT
Mostly cloudy. A chance of flurries in the evening, then a slight chance of light snow after midnight. Lows 16 to 20. West winds 5 to 10 mph. Chance of measurable precipitation 20 percent.

FRIDAY
Mostly cloudy. Slight chance of light snow in the morning, then a chance of flurries in the afternoon. Highs in the upper 20s. West winds 10 to 15 mph. Chance of measurable precipitation 20 percent.

FRIDAY NIGHT
Partly cloudy. A chance of flurries. Lows 16 to 20.

SATURDAY
Partly sunny. Highs in the mid 30s.

SATURDAY NIGHT
Partly cloudy. Lows in the upper 20s.

SUNDAY
Mostly cloudy with a 40 percent chance of rain and snow. Highs in the upper 30s.

SUNDAY NIGHT THROUGH TUESDAY
Partly cloudy. Lows in the mid 20s. Highs in the upper 30s.

12-48 Hr Surface, 12-48 Hr ETA 500mb/Sfc, TWC Forecast, Fire Danger, Day 1 Precip, Day 2 Precip, Days 1-5 Precip
NGM 60 Hr Forecast Meteograms : Springfield , Peoria , Quad City , Chicago (O'Hare) , Rockford , Severe Weather Pot.-Day 1, Day 2


Medium & Long Range Outlook For Illinois
                             ILLINOIS                                                                     
                 ---------------------------------------------
                 6 TO 10 DAY  8 TO 14 DAY   30 DAY    90 DAY 
                   DEC 18-22    DEC 20-26    DEC       DEC-FEB                      
                 -----------  -----------  --------  ---------
   Temperature:      Above       Normal     Normal     Normal                      
 Precipitation:      Below       Normal     Normal      Above                      

....  Medium and long range outlooks provided by NCEP/K. Thomas Priddy
5 Day Rainfall Forecast, 6 to 10 Day , 8 to 14 Day , Text, 30-Day Outook, 90-Day Outook, 120-Day Outlook
MRF 10-Day Forecast Meteograms : Springfield , Peoria , Quad City , Chicago (O'Hare) , Rockford

Almanac Information

Wednesday December 13, 2017 the 347th Day of Year

---------------------------------------------------
SUN
Declination -23.210000
Distance 0.999724 AU
Rise 08:12 EST Set 17:35 EST
Transit Meridian 12:53 EST
Civil Twilight Begins 07:43 EST Ends 18:04 EST

Calculations made for central point in the state.
Time in ET -- and will vary due to location and
elevation -- Priddy


Historical Weather And Climate Facts For Today

DECEMBER 13TH
HISTORIC WEATHER EVENTS
...1915...
A heavy snowstorm kicked off the snowiest winter in modern records for
western New England. (The Weather Channel)
...1962...
Record cold weather gripped the nation. The low temperature in Lexington, KY 
fell to -6 degrees (record low on this date), -3 at Covington and -3 at Paducah. 
Severe cold conditions went as far south as Florida with a hard freeze. Morning 
lows reached 35 degrees at Miami, 18 degrees at Tampa, and 12 degrees at 
Jacksonville. It was the coldest December weather of the 20th century and caused 
millions of dollars damage to crops and foliage. In Georgia, the morning low of 
9 degrees below zero at Blairsville established a state record for the month of 
December. 
...1987...
A major winter storm produced high winds and heavy snow in the Southern
Rockies and the Southern High Plains. Snowfall totals in New Mexico ranged
up to 25 inches at Cedar Crest, with up to three feet of snow reported in
the higher elevations. Winds of 75 mph, with gusts to 124 mph, were
reported northeast of Albuquerque NM. El Paso TX was buried under 22.4
inches of snow, including a single storm record of 16.8 inches in 24 hours.
The snowfall total surpassed their previous record for an entire winter
season of 18.4 inches. Record cold was experienced the next three nights as
readings dipped into the single numbers. High winds ushering unseasonably
cold air into the southwestern U.S. gusted to 100 mph at Grapevine CA. (The
National Weather Summary) (Storm Data)
...1988...
Low pressure off the Atlantic coast produced up to a foot of snow in
eastern Nassau County and western Suffolk County of southeastern New York
State. Mild weather prevailed across the western half of the country. Nine
cities reported record high temperatures for the date, including Goodland
KS with a reading of 74 degrees. (The National Weather Summary) (Storm
Data)
...1989...
Strong northwesterly winds, ushering bitterly cold arctic air into the
central U.S., produced squalls with heavy snow in the Great Lakes Region.
Snowfall totals in Upper Michigan ranged up to 24 inches at Manistique.
Nine cities in Arkansas and Texas reported record low temperatures for the
date, including Calico Rock AR with a reading of 4 degrees above zero.
(Storm Data) (The National Weather Summary)

Ag Weather Center, Department of Biosystems & Agricultural Engineering, University of Kentucky