BeastFromTheEast Posted February 27, 2011 Share Posted February 27, 2011 ...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO6 AM CST MONDAY...THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A WINTERWEATHER ADVISORY FOR FREEZING RAIN AND SLEET CHANGING OVER TOSNOW...WHICH IS IN EFFECT FROM 9 PM THIS EVENING TO 6 AM CSTMONDAY.* TIMING...FREEZING RAIN AND SLEET FROM 8 PM THROUGH MIDNIGHT...THEN SNOW UNTIL EARLY MONDAY MORNING.* ACCUMULATIONS...ONE TO TWO TENTHS OF AN INCH OF SLEET AND FREEZING RAIN. TOTAL SNOWFALL OF 2 TO 4 INCHES.* HAZARDS...ACCUMULATING SLEET AND FREEZING RAIN CHANGING OVER TO ACCUMULATING SNOW.* IMPACTS...FREEZING PRECIPITATION WILL CAUSE DANGEROUS DRIVING CONDITIONS. Link to comment Share on other sites More sharing options...
Hoosier Posted February 27, 2011 Share Posted February 27, 2011 LOT issues advisory for entire CWA Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 27, 2011 Author Share Posted February 27, 2011 LOT: A MIXED BAG OF PRECIPITATION WILL OCCUR FROM THIS AFTERNOON THROUGH MID DAY TOMORROW AS A STRONG WARM FRONT SETS UP ACROSS THE REGION. AS OF THIS AFTERNOON...A STRONG WARM FRONT HAS SET UP...EXTENDING FROM DEEPENING LOW PRESSURE OVER THE OKLAHOMA PANHANDLE TO THROUGH CENTRAL ILLINOIS AND INDIANA TO NORTHERN OHIO. AN UNSEASONABLY WARM...MOIST AND UNSTABLE AIRMASS LIES TO THE SOUTH OF THE FRONT...WITH LOW TO MIDDLE 50S DEWPOINTS ALREADY MOVING INTO CENTRAL ILLINOIS...WHILE TEMPERATURES HAVE CLIMBED INTO THE MIDDLE TO UPPER 50S. THERE HAS BEEN QUITE A BIT OF MODEL INCONSISTENCY IN HANDLING THIS SYSTEM...BUT THE GUIDANCE IS FINALLY COMING INTO LINE. ONE OF THE MAIN CONCERNS HAS BEEN HOW FAR NORTH THE WARM SURFACE AIR WILL PENETRATE AND HOW FAST THE COLD AIR WILL MOVE SOUTHWARD OUT OF WISCONSIN AND THE UPPER MISSISSIPPI VALLEY. THE AIRMASS IN THE VICINITY OF THE BOUNDARY WILL BE QUITE VOLATILE AND STRONG THUNDERSTORMS HAVE ALREADY BEEN OBSERVED IN THE AREA OF ELEVATED INSTABILITY TO THE NORTH OF THE BOUNDARY. FORECAST PWS INCREASE TO IN EXCESS OF 1 INCH IN THE WARM SECTOR AIR...AND AS THE REGION WILL REMAIN UNDER STRONG FORCING AT BOTH THE SURFACE AND ALOFT...EXPECT PERIODS OF STRONG SHOWERS AND THUNDERSTORMS TO CONTINUE WELL INTO THE EVENING. SOME STORMS HAVE ALREADY PRODUCED HAIL UP TO 1/2 INCH WITH BRIEF HEAVY DOWNPOURS. CONSIDERING THE PERSISTENT SOUTHWESTERLY FETCH OF WARM/MOIST AIR AT THE LOW LEVELS...A LOW LEVEL JET OF 55KT COUPLET WITH AN UPPER LEVEL JET OF 125KT...ALONG WITH PWS IN EXCESS OF 1 INCH...WIDESPREAD HEAVY RAIN IS LIKELY. CURRENTLY EXPECT STORM TOTAL QPF OF 1.0 TO 1.5 INCHES SOUTH OF I-80 AND 0.75 TO 1 INCH NORTH OF I-80 TO THE WISCONSIN BORDER 21Z THIS AFTERNOON TO 21Z TOMORROW AFTERNOON. HOWEVER...THIS QPF WILL BE DIVIDED AMONG VARIOUS PCPN TYPES. GIVEN THE EXPECTED TIMING OF THE CHANGEOVER FROM LIQUID TO FREEZING TO FROZEN...THE NORTHERN PORTIONS OF THE CWA SHOULD SEE THE MOST SNOW AND THE LEAST SLEET/FREEZING RAIN AND RAIN...WHILE THE SOUTHERN SECTIONS RECEIVE THE MOST RAIN AND FREEZING PCPN AND CONSIDERABLY LESS SNOW. WHEN ALL IS SAID AND DONE...EXPECT 2-4 INCHES OVER THE NRN PORTIONS OF THE CWA AND LESS THAN AN INCH OVER THE SERN SECTIONS. WITH THE MIXED BAG OF PCPN...TRAVEL MAY BECOME DIFFICULT ACROSS THE ENTIRE CWA AT SOME POINT TONIGHT. ONE WILDCARD IN THE PRECIPITATION FORECAST WILL BE CONVECTIVE ACTIVITY. THE HIGHER RESOLUTION MODELS ARE INDICATING THE POTENTIAL FOR BURSTS OF SIGNIFICANTLY HIGHER PRECIPITATION RATES THAN CURRENTLY FORECAST. IT IS DIFFICULT TO ASCERTAIN IF THE CONVECTIVE BURSTS ARE UNREALISTIC CONVECTIVE FEEDBACK OR A REAL SIGNAL INDICATING THE REAL POTENTIAL FOR SIGNIFICANTLY HIGHER PRECIPITATION AMOUNTS. DO NOT FEEL COMFORTABLE INCLUDING HIGHER SNOW OR SLEET/FREEZING RAIN ACCUMULATIONS IN THE FORECAST...BUT THE POSSIBILITY CANNOT BE ENTIRELY RULED OUT. Link to comment Share on other sites More sharing options...
Hoosier Posted February 27, 2011 Share Posted February 27, 2011 Gotta admire the zone forecast for Chicago/Cook county. I love the Midwest. TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS LATE IN THE AFTERNOON...THEN RAIN SHOWERS...THUNDERSTORMS...CHANCE OF FREEZING RAIN AND SLEET IN THE EVENING. FREEZING RAIN...SLEET AND A CHANCE OF LIGHT SNOW AFTER MIDNIGHT. SOME THUNDERSTORMS MAY PRODUCE HEAVY RAINFALL. SNOW AND SLEET ACCUMULATION OF 1 TO 2 INCHES. LOWS IN THE LOWER 30S. LIGHT AND VARIABLE WINDS LATE IN THE AFTERNOON BECOMING NORTH 10 TO 20 MPH. CHANCE OF PRECIPITATION 100 PERCENT. Link to comment Share on other sites More sharing options...
Hoosier Posted February 27, 2011 Share Posted February 27, 2011 Down to 33 at ORD and 34 at Gary. It could get very interesting in northern IL and far northwest Indiana later tonight. Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 27, 2011 Share Posted February 27, 2011 Just saw 32 on the bank clock at lasalle and wacker, probably bunk, but it's cold. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 27, 2011 Share Posted February 27, 2011 Just saw 32 on the bank clock at lasalle and wacker, probably bunk, but it's cold. northeast flow off the lake FTW, or FTL? lol Link to comment Share on other sites More sharing options...
BeastFromTheEast Posted February 27, 2011 Share Posted February 27, 2011 Going to be a fun/long night watching these maps lol.. Link to comment Share on other sites More sharing options...
Hoosier Posted February 27, 2011 Share Posted February 27, 2011 32 at ORD KORD 272321Z 05008KT 1 1/2SM -DZ BR BKN005 OVC020 00/M01 A2968 RMK AO2 TWR VIS 2 P0000 Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 27, 2011 Share Posted February 27, 2011 It looks like there is a light area of precip forming in east central Iowa into northwest Illinois. I wonder if that might fill in, strengthen, and start to threaten part of extreme northern Illinois and southern Wisconsin. Link to comment Share on other sites More sharing options...
BeastFromTheEast Posted February 27, 2011 Share Posted February 27, 2011 New Mesoscale discussion out...Boy oh Boy things could get nasty... AREAS AFFECTED...SERN IA...EXTREME NRN MO...NWRN/N-CNTRL IL CONCERNING...WINTER MIXED PRECIPITATION VALID 272350Z - 280545Z A WINTRY MIX IS ANTICIPATED ACROSS PORTIONS OF SERN IA...EXTREME NRN MO...AND NWRN/N-CNTRL IL THIS EVENING. FREEZING RAIN IS EXPECTED IN THIS AREA...WITH RATES AOA 0.05 INCH PER HOUR POSSIBLE. INCREASING ASCENT OVER THE CENTRAL PLAINS HAS AIDED IN INITIATING A CONVECTIVE COMPLEX OVER PORTIONS OF NRN MO...WITH STRATIFORM PRECIP CURRENTLY EXTENDING INTO SRN IA. AS THIS ACTIVITY IS STEERED NEWD THIS EVENING...AND ADDITIONAL SCATTERED CONVECTION DEVELOPS UPSTREAM OVER PORTIONS OF ERN KS...PRECIPITATION WILL CONTINUE TO INCREASE ACROSS THE DISCUSSION AREA. OBJECTIVE ANALYSIS AT 23Z DEPICTS THE SFC FREEZING LINE EXTENDING FROM NEAR DKB TO JUST NORTH OF LWD. COLD AIR ADVECTION ACROSS THE REGION IS FORECAST TO NUDGE THE FREEZING LINE SWD THIS EVENING. FREEZING RAIN WILL BE THE PRIMARY CONCERN NORTH OF THIS LINE...GIVEN ELEVATED WARM NOSE TEMPERATURES AOA 3C PER RUC FORECAST SOUNDINGS. HOWEVER...LATER IN THE EVENING...ADDITIONAL LOW-LEVEL COOLING IS ANTICIPATED...WHICH COULD ALLOW SLEET AND SNOW TO ALSO OCCUR. FREEZING RAIN RATES AOA 0.05 INCH PER HOUR WILL BE POSSIBLE...ESPECIALLY ACROSS PORTIONS OF SERN IA AND NWRN/N-CNTRL IL WHERE THE PRESENCE OF ELEVATED INSTABILITY COULD ENHANCE UPRIGHT CONVECTION IN ADDITIONAL TO THUNDERSTORM ACTIVITY. MOST OF THE PRECIPITATION IS EXPECTED TO HAVE MOVED EWD INTO IL BY 07Z. ..COHEN.. 02/27/2011 Link to comment Share on other sites More sharing options...
turtlehurricane Posted February 28, 2011 Share Posted February 28, 2011 I'm really hoping the precip makes it this far, it's gonna be close I think. The cutoff will be very sharp. Reports of rain and sleet in MO and IA, probably will start seeing snow reports in that deep frontogenetic band over IA. Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 28, 2011 Share Posted February 28, 2011 I'm really hoping the precip makes it this far, it's gonna be close I think. The cutoff will be very sharp. Reports of rain and sleet in MO and IA, probably will start seeing snow reports in that deep frontogenetic band over IA. We just have to hope the broad band of precip starts to turn more NE rather than ENE. Maybe the band can take a surprise turn more northward. Link to comment Share on other sites More sharing options...
OHSnow Posted February 28, 2011 Share Posted February 28, 2011 Thunderstorms here, despite the solid snow cover. Link to comment Share on other sites More sharing options...
Chicago WX Posted February 28, 2011 Share Posted February 28, 2011 I just noticed, but pretty cool that Kansas City is under a Severe Thunderstorm Watch while sitting at 34/32 right now. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 28, 2011 Share Posted February 28, 2011 0z DVN sounding.. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 28, 2011 Share Posted February 28, 2011 nice MCV in west central IL with an intense line of storms west of ILX moving northeast.. Link to comment Share on other sites More sharing options...
MadTown Posted February 28, 2011 Share Posted February 28, 2011 my take right now is i don't think the northern edge makes it more than 60mi more north than where it is right now. Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2011 Share Posted February 28, 2011 intense line of storms west of ILX moving northeast.. Yeah there are warnings on those. 31 at ORD... Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 28, 2011 Share Posted February 28, 2011 It looks like Cedar Rapids is seeing some light freezing rain or snow on the radar. This is relevant because their forecast for tonight was 30% chance of a wintry mix. I maybe reaching, but maybe the band of moisture is just a tad northwest of what most of the models projected. Dubuque and Madison may even be able to squeak in on some action if they're lucky. Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 28, 2011 Share Posted February 28, 2011 my take right now is i don't think the northern edge makes it more than 60mi more north than where it is right now. That would go along with the forecast. The good thing though, as I detailed, is that it looks like Cedar Rapids and maybe even Dubuque might get in on some freezing rain or snow. Both cities only expected a small chance of anything. Link to comment Share on other sites More sharing options...
cyclone77 Posted February 28, 2011 Share Posted February 28, 2011 Looks like the best icing might set up from Burlington/Galesburg up towards Dekalb/Chicago. Think we'll see some minor glazing here, with the heaviest southeast. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 28, 2011 Share Posted February 28, 2011 Yeah there are warnings on those. 31 at ORD... going to be very interesting to see what the convection does to the thermal profiles around here.. Link to comment Share on other sites More sharing options...
csnavywx Posted February 28, 2011 Share Posted February 28, 2011 0z DVN sounding.. Holy crap at those lapse rates from 700 on up. Must be pushing 9C/km. Very intense cells moving near Quincy. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 28, 2011 Author Share Posted February 28, 2011 It looks like Cedar Rapids is seeing some light freezing rain or snow on the radar. This is relevant because their forecast for tonight was 30% chance of a wintry mix. I maybe reaching, but maybe the band of moisture is just a tad northwest of what most of the models projected. Dubuque and Madison may even be able to squeak in on some action if they're lucky. That would go along with the forecast. The good thing though, as I detailed, is that it looks like Cedar Rapids and maybe even Dubuque might get in on some freezing rain or snow. Both cities only expected a small chance of anything. You're getting ahead of yourself. CID is riding the edge of the precip shield and it will stay south of Dubuque. Link to comment Share on other sites More sharing options...
csnavywx Posted February 28, 2011 Share Posted February 28, 2011 Intense lightning showing up on those storms too. Link to comment Share on other sites More sharing options...
Moneyman Posted February 28, 2011 Share Posted February 28, 2011 wisconsin and MadTow, it's game over for us. Just couldn't do it. Models have a very good handle on things now. Time to look towards the Thu/Fri event and another storm later that weekend. Link to comment Share on other sites More sharing options...
MadTown Posted February 28, 2011 Share Posted February 28, 2011 thats what i was going with the 60mi more northward...the band that was southwest of cedar rapids is moving ene not northeast oh well...guess i should have locked in southern wi a day earlier on this one Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2011 Share Posted February 28, 2011 The 00z ILX RAOB had 700-500 mb lapse rates in excess of 8 C/km Link to comment Share on other sites More sharing options...
hawkeye_wx Posted February 28, 2011 Share Posted February 28, 2011 It looks like Cedar Rapids is seeing some light freezing rain or snow on the radar. This is relevant because their forecast for tonight was 30% chance of a wintry mix. I maybe reaching, but maybe the band of moisture is just a tad northwest of what most of the models projected. Dubuque and Madison may even be able to squeak in on some action if they're lucky. We are getting what looks like a pretty good freezing mist. The car windows are glazed and the pavement is shiny. It appears the precip is as far nw as it will ever be in Iowa. Link to comment Share on other sites More sharing options...
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