Short Range Web Technical
Analysis made at 2:00pm EST 17 Feb 2014
Throughout this afternoon, heavy convective precipitation bands will move through Indiana due to significant convective lifting. The GFS indicates omega values below -20 will pass along with the Westerly flow over Central Indiana between 1800Z and 0000Z today. This lift has a great influence from vorticity, as a large vorticity maximum at 500mb is associated with the Low Pressure and deep trough. Types of precipitation will vary through lower Central and Southern counties, as early precipitation will occur above the 540 line and due to a warm layer aloft. So areas may see mixed winter precipitation in the form of freezing rain or sleet this afternoon, but as the front passes, temperatures will drop and most precipitation will be snow. Late in the afternoon, cold air from aloft move in...and due to the convective nature of this storm, localized total precipitation may total up to around 5 inches (especially in the Northern areas), but generally the snowfall will total somewhere from 1-3 inches except in the South of the state, where surface temperatures are warming to near freezing. There is a possibility for lightning as the system moves through.
Scattered snowfall may continue through to early Tuesday as the low pressure and trough move out of the area. Warm air advection will follow the system as a ridge moves in warmer temperatures on Wednesday until Thursday evening. GFS runs show a slight chance for us to see some precipitation from a lower band branching off a low pressure system in lower Canada on Wednesday, but the NAM doesn't agree. This weaker trough will move out by early Thursday. Model runs show that the next big system on Thursday afternoon/evening looks to contain significant ingredients for severe weather. At 700mb, there is lots of moisture and lift, warm air advection values are looking to be very large and there is a large vorticity maximum.
Written by Grant McKercher