National Weather Service Forecast for: Peotone IL Issued by: National Weather Service Chicago, IL

Updated: 1:02 pm CST Feb 22, 2012

This Afternoon Rain/Snow Likely Tonight Rain/Snow Likely Thursday Rain/Snow Likely Thursday Night Chance Snow Friday Chance Showers Friday Night Mostly Cloudy Saturday Mostly Sunny Saturday Night Partly Cloudy Sunday Slight Chc Showers Hi 46 °F Lo 36 °F Hi 47 °F Lo 30 °F Hi 39 °F Lo 25 °F Hi 35 °F Lo 25 °F Hi 44 °F

Forecast from NOAA-NWS for Peotone IL.

000
FXUS63 KLOT 221748
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1148 AM CST WED FEB 22 2012

.DISCUSSION...
638 AM CST

LIGHT SNOW CONTINUES TO TRAVERSE THE AREA THIS MORNING...HOWEVER
IT APPEARS THE LIFT MECHANISM THAT PUSHED PARTICLES INTO THE
FAVORED DENDRITIC GROWTH ZONE IS BEGINNING TO DIMINISH. MINIMAL
PRESSURE GRADIENT WAS NOTED AMONGST SFC OBS...SUGGESTING THAT MOST
OF THE LOW LEVEL MOISTURE MAY END UP TRANSITIONING INTO A PATCHY
DRIZZLE. THIS MAY ALSO AID IN SOME PATCHY FOG ACROSS THE
AREA...BEFORE BETTER LIFT ARRIVES LATER THIS MORNING. AT THIS TIME
HAVE NOT MADE ANY ADJUSTMENTS TO THE GOING FORECAST.

REGIONAL RADAR MOSAIC CONTINUES TO INDICATE THE HEAVIEST OR MORE
STEADY LIGHT SNOW CONTINUES TO PUSH EAST ALONG THE I-80 CORRIDOR
INTO NORTHWEST INDIANA. HI-RES GUIDANCE SUGGESTS THAT THIS TREND
WILL CONTINUE...BEFORE COMING TO AN END LATER THIS MORNING.

BEACHLER

//PREV DISCUSSION...
347 AM CST

CHALLENGES IN THE NEAR TERM RESIDE WITH ENHANCED FORCING THAT
CONTINUES TO PUSH NORTHEAST ACROSS FAR SOUTHEAST IOWA AND WEST
CENTRAL ILLINOIS. HI-RES GUIDANCE CONTINUES TO SUGGEST THAT A NARROW
BAND OF SNOW WILL DEVELOP FOR THE MORNING COMMUTE OVER NORTHCENTRAL
ILLINOIS...MAINLY FOCUSED ALONG THE I-80 CORRIDOR. WHILE TEMP/DEW PT
SPREADS REMAIN BETWEEN 6 AND 9 DEG SPREAD...IT APPEARS WE SHOULD
MOISTEN THE NEAR SFC ENVIRONMENT QUICKLY WITH THIS ENHANCED FORCING.

TEMPS HAVE REMAINED NEARLY STATIONARY IN THE LOW 30S...WITH A FEW
POINTS ACROSS FAR SOUTHWEST SECTIONS OF THE CWFA RISING A COUPLE OF
DEGREES INTO THE MID 30S. IR IMAGERY EARLY THIS MORNING CONTINUES TO
DEPICT COOLING CLOUD TOPS ASSOCIATED WITH THE AFOREMENTIONED FORCING
REGION...WITH TEMPS COOLING TO ARND -44 TO -46 DEG C. THIS SUGGESTS
THAT PRECIP IS NEARLY READY TO BEGIN...AND IS SUPPORTED BY THE
REGIONAL RADAR MOSAIC INDICATING INCREASED RETURNS.

ONCE THIS BAND OF PRECIPITATION FORMS...IT WILL QUICKLY PRESS EAST
AND SHOULD DEPART THE CWFA BY 18Z. IT IS POSSIBLE THAT WITHIN THE
HEAVIEST AREA OF PRECIPITATION...AND ASSUMING IT DOES FALL AS
SNOW...THAT ACCUMULATIONS COULD APPROACH 1 TO 2 INCHES FOR THE
SOUTHERN AND SOUTHWESTERN SUBURBS OF CHICAGO EXTENDING EAST ALONG
I-80 INTO FAR NORTHWEST INDIANA.

THIS SYSTEM WILL HAVE A FEW THINGS HINDERING THE FULL DEVELOPMENT
AND THAT IS THAT MANY LAPS SOUNDINGS HAVE INDICATED SUBSTANTIAL DRY
AIR REMAINS IN THE MID-LVLS AND NOT MOISTENING AT THIS TIME. IN
ADDITION TEMPS HAVE COME UP A FEW DEGREES WITH SOUTHERLY
FLOW...WHICH MAY MAKE IT DIFFICULT FOR THE DENDRITES TO MAINTAIN
THEMSELVES TO THE SFC. THAT BEING SAID...HAVE MARGINALLY MORE
CONFIDENCE THAT LGT SNOW WILL INDEED OCCUR AND HAVE MAINTAINED THE
FORECAST THIS WAY.

500MB VORT MAX CONTINUES TO PRESS EAST ACROSS EASTERN LAKE SUPERIOR
WITH AN 850MB THERMAL TROUGH OF -2 TO -4 DEG C OVER THE CWFA EARLY
THIS MORNING. LATEST GUIDANCE CONTINUES TO FAVOR MINIMAL ADJUSTMENTS
TO THIS FIELD...AND SFC TEMPS ARE PROGGED TO WARM INTO THE LOW/MID
40S FOR CENTRAL/NORTHERN CWFA. LOCATIONS SOUTH OF I-80 COULD SEE
TEMPS RISE INTO THE UPPER 40S POSSIBLE ARND 50 BY THIS AFTN.

TONIGHT THROUGH THURSDAY...
THE FOCUS WILL BE ON YET ANOTHER POTENTIAL ROUND OF LGT SNOW FOR
THUR AND THE PLACEMENT OF A DEVELOPING SHORTWAVE. GUIDANCE HAS BEEN
MEANDERING ON THE PLACEMENT OF A WAVE EXPECTED TO PUSH INTO THE
NORTHERN PLAINS...AND SLIDE EAST/SOUTHEAST ACROSS THE UPPER MIDWEST
EARLY THUR. A FEW OTHER GUIDANCE MEMBERS HAVE FAVORED A SLIGHT SOUTH
TRACK...HOWEVER ONE CONSISTENT ELEMENT HAS BEEN THE 850MB THERMAL
RIDGE THAT IS ADVERTISED TO ADVECT OVERHEAD EARLY THURSDAY MORNING.
TEMPS ALOFT WILL WARM TO ARND 2 TO 4 DEG C BY 15Z. THE CURRENT
THINKING IS THAT PRECIP WILL DEVELOP ALONG THE LEADING EDGE OF A
FRONTAL BOUNDARY THAT WILL LIFT NORTH ACROSS THE AREA. AS HAS BEEN
THE CASE BEFORE...P-TYPE REMAINS A CHALLENGE. EXPECT THAT SOUTH OF
I-80 PRECIP WILL FALL AS LGT RA. FURTHER NORTH WITH SLIGHTLY COOLER
TEMPS THE PRECIP MAY MIX OR CHANGE TO LGT SN. AT THIS TIME SOME
LIGHT ACCUMS ARE POSSIBLE...AND SHOULD GENERALLY BE AROUND 1 INCH
MAINLY FOR LOCATIONS NORTH OF I-88 OR CLOSER TO THE WISCONSIN
STATELINE. HAVE BOOSTED POPS TO LOW END LIKELY FOR MUCH OF THE
AREA...AGAIN WITH THE FOCUS BEING ALONG THE WARM FRONTAL BOUNDARY
WHERE MOISTURE WILL CONSOLIDATE.

TEMPS OVERNIGHT WILL REMAIN MILD AS A THICK CLOUD COVER SHOULD
REMAIN. THUS EXPECT TEMPS IN THE MID/UPR 30S. THEN FOR THUR AFTN
TEMPS WILL EASILY WARM INTO THE LOW/MID 40S. POSSIBLY FOR THE
SOUTHERN CWFA TEMPS ARND 50.

AS THE SHORTWAVE CONTINUES TO DEVELOP THUR AFTN AND PUSH EAST...A
SECONDARY AREA OF LOW PRESSURE IS PROGGED TO DEVELOP ACROSS THE OHIO
VALLEY. GUIDANCE HAS BEEN FAVORING THIS TO BECOME A MORE POTENT
SYSTEM LATE THUR INTO FRI...HOWEVER SHOULD NOT POSE ANY IMPACT AT
THIS TIME TO THE CWFA.

FRIDAY THROUGH TUESDAY...
ENSEMBLES CONTINUES TO FOCUS ON A DIGGING 500MB TROUGH ACROSS THE
GREAT LAKES REGION...SHOWING SOME WEAKENING OVER THE COURSE OF THE
UPCOMING WEEKEND. WEAK RIDGING IS PROGGED TO OCCUR SAT NGT/SUN AS A
NEW TROUGH IS POISED TO PUSH INTO THE ROCKIES. THIS APPEARS TO AID
IN AMPLIFYING A DOWNSTREAM RIDGE FOR THE EASTERN THIRD OF THE CONUS
FOR EARLY NEXT WEEK. SOME WARMING CONTINUES TO BE NOTED WITH RESPECT
TO THE MEAN OF THE ENSEMBLE MEMBERS...LEANING TOWARDS POSSIBLY ABOVE
NORMAL TEMPS.

IT SHOULD BE NOTED THAT A FEW GUIDANCE MEMBERS CONTINUE TO POINT
TOWARDS A POTENT SYSTEM DEVELOPING ACROSS THE SOUTHERN ROCKIES AND
TRAVELING NORTH THROUGH THE UPPER MIDWEST EARLY NEXT WEEK. IN
ADDITION THIS WAS SUGGESTING A STRONG SOUTHERLY FLOW AHEAD OF THIS
SYSTEM...AND THE POSSIBILITY FOR CONVECTION ACROSS PORTIONS OF THE
OHIO AND TENNESSEE VALLEYS. WHILE THIS IS SEVERAL DAYS
AWAY...GUIDANCE HAS BEEN HINTING AT THIS FOR A COUPLE CYCLES.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* SOUTHWEST WINDS CONTINING.

* CHANCE OF A FEW SHRA IN THE AREA THIS AFTERNOON.

* RAIN/SNOW POSSIBLE THURSDAY MORNING. MVFR CONDITIONS LIKELY.

PAW

//DISCUSSION...UPDATED 18Z...

VFR CONDITIONS PREVAILING THROUGH THIS EVENING. AN AREA OF SPOTTY
SHRA ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE MOVING EAST FROM
IA/WI WILL SWING ACROSS NORTHERN IL DURING THE AFTERNOON HOURS.

A STRONGER SYSTEM WILL BE MOVING INTO THE AREA LATE TONIGHT AND
INTO THE DAY ON THURSDAY. LITTLE AGREEMENT BETWEEN THE MODELS ON
THE DETAILS...SO CONFIDENCE IN THE FORECAST IS LOW AT THIS TIME.
FOR NOW IT APPEARS PRECIPITATION WILL START AS SNOW OR A MIX OF
RAIN/SNOW EARLY THURSDAY MORNING AND TRANSITION TO RAIN DURING
THE DAY. CONDITIONS LOWERING TO MVFR WITH THE PRECIPITATION.

PAW


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN WIND TREND TODAY.

* LOW CONFIDENCE IN ANY SHRA AT THE TERMINALS THIS AFTERNOON.

* LOW CONFIDENCE IN PRECIPITATION AND ASSOCIATED
  CEILING/VISIBILITY THURSDAY MORNING.

PAW

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...CHANCE OF SNOW SHOWERS AND MVFR CONDITIONS.

FRIDAY...CHANCE OF RAIN/SNOW SHOWERS AND MVFR CONDITIONS.

SATURDAY...VFR.

SUNDAY...CHANCE OF RAIN/SNOW SHOWERS AND MVFR CONDITIONS.

MONDAY...CHANCE OF RAIN/SNOW SHOWERS AND MVFR CONDITIONS.

TUESDAY...VFR.

RODRIGUEZ

&&

.MARINE...
219 AM CST

THE WEATHER PATTERN ACROSS THE CENTRAL CONUS WILL REMAIN ACTIVE INTO
NEXT WEEK. THIS WILL RESULT IN A FEW WIND EVENTS THROUGH THE
PERIOD.

SOUTHWESTERLY WINDS WILL CONTINUE TODAY AS SURFACE LOW PRESSURE
ACROSS LAKE SUPERIOR SHIFTS EASTWARD ACROSS SOUTHEASTERN ONTARIO
THROUGH THE DAY. WIND SPEED WILL DECREASE THIS AFTERNOON AS THE
PRESSURE GRADIENT BEGINS TO WEAKEN.

ANOTHER AREA OF LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE MID
MISSISSIPPI VALLEY ON THURSDAY MORNING. THIS LOW WILL CONTINUE ACROSS
THE OHIO VALLEY ON THURSDAY NIGHT...AND FINALLY MOVE UP THE EAST
COAST BY LATE THIS WEEK. THIS WILL SET UP A PERIOD OF
NORTHWESTERLY WINDS IN TO 20 TO 30 KT RANGE FRIDAY INTO SATURDAY.

ANOTHER POTENT AREA OF LOW PRESSURE LOOKS TO DEVELOP ACROSS THE
CENTRAL HIGH PLAINS BY SATURDAY NIGHT. THIS LOW IS FORECAST TO TRACK
EAST NORTHEASTWARD ACROSS THE UPPER GREAT LAKES ON MONDAY. THIS
SYSTEM HAS A GOOD POTENTIAL TO PRODUCE A PROLONGED PERIOD OF
GALE FORCE WINDS. SOUTHEASTERLY WINDS LOOK TO INCREASE ON SUNDAY AS
THE LOW MOVES ACROSS THE MID MISSOURI VALLEY. FINALLY LATE SUNDAY
NIGHT AND MONDAY IT APPEARS THAT A STRONG FRONTAL ZONE WILL SHIFT
EAST ACROSS THE LAKE. THIS COULD RESULT IN WEST TO SOUTHWESTERLY
GALES FOR MONDAY AND MONDAY NIGHT.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

NWS LOT Office Area Forecast Discussion