1″ or Less Late Morning-Afternoon Today In Places with Clipper….Tonight & Thursday Night-Friday InformationJanuary 23rd, 2013 at 11:13 am by Chad Evans under Chad's WLFI Weather Blog
Passing clipper today will deposit 1″ or less of snowfall is possible in places this late morning-afternoon. Highs will be in the 20s with brisk west to southwest winds up to 22 mph, bringing wind chills down to 8.
It also appears some lake affect snow showers will be possible tonight as lake effect snow shower band that is oriented northwest-southeast northeast of the viewing area, swings around & orients itself north to south from Gary to Rensselaer to Monticello to Fowler & perhaps Lafayette.
ANALOG & MOST FOREIGN MODELS PAINT A DECENT SNOWFALL…..U.S. NAM MODEL IS LONE RANGER WITH NOT A SINGLE FLAKE
Models continue to show horrendous disagreement regarding Thursday night-Friday system. Noticed NWS Indianapolis dropped 4″ mention down to 1″ & Northern Indiana office says up to 3″. Northern Indiana NWS office says snowfall ratio 17:1……..Indianapolis NWS says 12:1. I like North Webster’s 17:1 ratio best. I still prefer 18:1, which makes forecast hard with even 0.10″ liquid giving you 2″ of snowfall. North Webster still indicates uncertainty, which I am in line with. In their forecast discussion “surprise amounts/ratios” are mentioned: “SNOW RATIOS COULD BE ABOVE CLIMO (USED 17:1) GIVEN A DGZ NEARLY 10-12 KFT DEEP. THIS COMBINED WITH THE OUTSIDE SHOT OF A MORE ROBUST MID LVL FGEN RESPONSE JUST IN ADVANCE OF THE WAVE COULD LEAD TO SURPRISE AMOUNTS/RATIOS.”
Eastern Indiana/western Ohio NWS office has totally thrown out the NAM model for the forecast & prefers to use GFS/European blend. They like 2″ with potential of isolated locations seeing +4″.
Lincoln, Illinois NWS (forecasts for county just west of Warren in Illinois) office makes no mention of ratios, but tends to side with NWS Indianapolis more. They have 1″ or less of accumulation.
Chicago NWS gives no numbers from ratios to accumulations (forecasts for Newton, Jasper & Benton). They only say “light accumulations”.
U.S. NAM has not a single flake with not northern & southern system merger. U.S. GFS has up to 3″. Analog supports accumulating snowfall of 3-6″. Japanese model (JMA) has up to 0.50″ liquid & generally 3-7″. NOGAPS has a 3-5″ snow, while UKMET has 3-6″. European has the northern low as the dominant one & less snow here, but some (up to 1.5″). Canadian GEM has a 1-3″ snow. The Japanese model brings the greatest accumulation & best organization for a snowfall event & then re-forms a Nor’Easter on the East Coast with heavy snowfall there & quite a bit of wind.
Tough call on what direction to go. On one hand, I rely much on analog, which points towards a merger & 3-6″. However, I do not want to go there & have people waste money & time on preparation (specifically snow removal companies) if the NAM is correct. Indianapolis NWS likes a much lower snowfall amount of 1″ with a 12:1 ratio, but I have seen this happen before of 1-2″ in these situations & you get 3-6″. Happened a few weeks ago in southern Indiana & left people unprepared.
Even today with clipper, frontagenical band has set up in north-central Illinois with weak clipper with moderate to heavy snow over a 5-mile by 50 mile band. 2″ have fallen in band when flurries or 30% chance of light snowfall forecasted.
I think either way this forecast is going to be awful, unless there is much better agreement this afternoon-evening & into tomorrow. Even National Weather Service forecast offices do not agree with each other on amounts & snow ratios in the viewing area (12:1 or 17:1), let alone models. I will make a decision on whether to alter the 3-6″ later today once I get the 18z model runs (out later this afternoon) under my belt.