I noticed this in the Visible satellite imagery a couple of days ago and saved some data. If you look closely at the loop below, you'll see a subtle rotation in the clouds northwest of Sioux Falls, SD:
(click on the image to see a larger version)
When comparing this with the 20z RUC analysis, you can clearly see the meso-low in the 500mb vorticity fields over the same area:
Kind of cool to see the meso-low being picked up in both the 13km RUC data and in the Visible satellite image.
Showing posts with label computer models. Show all posts
Showing posts with label computer models. Show all posts
The models over the past week had been hinting at a day or two in the 60's to 70's yesterday and today. While yesterday we didn't exactly hit the 60° mark, the airport recorded a high of 59° while here in town at the NWS office, 52° was recorded.
Today could be a different story. The NAM/GFS/GEM consensus has us, at least, hitting 70 degrees, with the GEM warmest, having us into the upper 70's.
Output from the NAM and GEM, respectively, follows - indicating their respective maximum 2m Temperature forecasts for this afternoon:
Winter Storm and Heavy Snow Warnings have been issued for much of the Ohio Valley today and are valid from this afternoon through most of Sunday.
It appears that most of Indiana and Ohio will see significant snowfall with this system, with northern areas seeing the heaviest accumulations. While computer models differ some on their precipitation forecasts, the most aggressive (the NAM, or North American-Mesoscale) model is painting quite the picture for parts of Indiana:
The image below indicates that heavy snow will begin late tonight over western parts of Indiana, then spreading northeastward during the overnight and into early Sunday morning. The image below shows a maximum accumulation of liquid of 0.989, which assuming a 10:1 ratio, would amount to near 10 inches of snow, but paints most of northern Indiana over 0.75 or 7-8 inches of snow by 12Z on Sunday. This is equivalent to 7:00am EST. Note, this also only indicates snowfall during the previous 6 hours - so this is 7-8 inches within a 1:00am to 7:00am period. Nearly an inch per hour! If that would actually occur, that's pretty impressive!
This next image from 18Z, or 1:00pm EST shows the next 6-hr period and indicates another 5 to 8 inches over north-central and northeastern Indiana. This would bring a total accumulation from 12 to 16 inches of snow!
And finally, the last 6 hours of the event, for the most part, indicates only light accumulations (generally an inch or less) associated with lighter snow and flurries through 00Z Monday, or 7:00pm EST, Sunday evening.
Things should be much quieter by this time, but I'm sure all you Hoosiers will all see a much whiter world tomorrow!
If you are reading this from Indiana and would happen to snap any photos of this snow event, please pass them along! I'd love to see how things pan out. While I don't exactly feel that 17-18 inches will fall, I'm confident enough to say that a 12 inch accumulation will be likely, somewhere, and that there is a possibility that there could be some local spots of slightly higher accumulations.
My personal snowfall forecast would sound something along these lines...
+ Locations north of a line from Crawfordsville to Portland: 8-12 inches (slightly higher, locally)
+ Locations south of this line and north of a line from Terre Haute through the south-side of Indy to Richmond: 4-8 inches
+ Locations south of this line and north of a line from Vincennes to Lawrenceburg: 1- 4 inches of snow with light ice (freezing rain or sleet) accumulations possible
+ Points southward: an inch or two, with ice accumulations up to a quarter-inch also possible Sunday afternoon
Now this just sucks...
For those of you that don't typically look at numerical guidance, this is indicating areas of light snow across portions of North Dakota Saturday. Granted, it likely won't amount to anything (soil temperatures are still quite mild) but any snowfall is snowfall I'm not prepared for! I'd much rather skip over the next 5 months and go right into spring and early-summer. ;)
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