3 hours is pushing it . Things are really speeding up . For sure won’t be longer than that
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Wintry January 29th-30th ARCC Slam Dunk Winter Weather Threat
- Thread starter ForsythSnow
- Start date
3 hours is pushing it . Things are really speeding up . For sure won’t be longer than that
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Ron Burgundy
Member
This call map seems a tad...bullish. Firsthand Weather has a near cult following on FB. Anyone know who the met(s) are at this site?
Snowflowxxl
Member
NAM was moisture starved all around. We will see if it was a blip or reality tonight I suppose.
Kylo
Member
3km looks reasonable. Has 3-4" in Roxboro.
accu35
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looking back again, your right. 3 hours or so can put down good bit of snow with heavy rates.
The event that I mentioned earlier (1/17/18) didn't have much cold air ahead of it either.
Yet, the sudden drop in temperatures led to a flash freeze of the preceeding rainfall (with 3-4" of snow on top of it).
The roads were skating rinks for a good 2 days (even with full sunshine). That was the one where Coweta County banned everyone from traveling those days.
Newnan does at least have *some* snow/ice removal equipment. I can only imagine how bad it would be for those areas that have none.
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accu35
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I really don't believe this map, but there should be 1-2" widespread with isolated 3s
Might get an hour or 2 at best
With full sunshine, temps have to be pretty well below freezing for roads to remain a skating rink. You get full sunshine and temps in the 30s and the areas where the sun hits will melt fairly fast on roads that are well traveled.
lusting4Adusting
Member
Really good Huntsville discussion this afternoon.
An upper trough will dig into the Central Plains on Monday, with a surface low moving into the Great Lakes region. A cold front trailing south of this parent low will make its way eastward and arrive into
the Mississippi River by sunset on Monday. Ahead of this, southwest flow through the vertical column will begin to filter moisture northward and into the TN Valley. Given ample sunshine and WAA,temperatures will feel quite warm, with highs in the mid to upper 50s during the day. A secondary piece of energy dropping SE out of the northern Rockies and into the ArkLaTex region will trigger pressure falls over southern MS/LA and a weak surface wave is progged to develop. This secondary wave will work in concert with the parent upper level trough to increase vertical motions over the area between 06-12z Tuesday and coincide with our best chances for snowfall.Thinking snow could start as early as 06z in NW AL and be coveringmuch of the TN Valley by 09z. Then as the front and upper wave shift E/SE expect snow to end from NW to SE after 12z Tuesday.
South to southwesterly winds ahead of this feature will allow forPWATs upwards of 0.75 inches to advect into the area. While notoverly anomalous for this time of year, these values are on thehigher side for a winter weather type of an event. As the forcing tied to the features mentions above overspread the area, expect a band of rain to develop as early as 9 PM along the MS River and W TN. Then as the Arctic front and secondary trough shift south this bandof precip will move into NW AL. Forecast soundings suggest that enough of a warm layer will exist near the surface to keep this initial band of rain in liquid form. However, the strength of the Arctic front will send temps quickly below freezing early Tuesday morning and we can expect a rapid transition to all snow. Ensemble probability guidance has shown high confidence in receiving at least a quarter inch of QPF but low probability of anything more than 0.5 inches. So, have adjusted our QPF based on this thinking and values come in around 0.3 inches. Not all of this will be falling as snow and it`s possible that up to 0.1 inch could fall as rain before the change over. Snow ratios will be close to 10 to 1 and that puts snowfall amounts on the low end at 1 inch and on the high end 2.5 to 3 inches.
While the speed of the front might limit the overall length/time period for snow, time-height analysis from various data sets were all indicating a stronger vertical motions either in the dendritic snow growth zone or just below. This would suggest the potential for some brief heavier snowfall rates in any mesoscale banding that develops. Total snowfall plumes from various data sets were trending the mean snowfall towards the 1.5 to 2 inch range. Our current forecast fall inline with these values with some locations in southern middle TN receiving upwards of 2.5 to 3 inches.
These amounts occurring either just before or possibly during the morning commute on Tuesday has prompted the need for a Winter Storm Watch to highlight the potential for travel impacts. Even though we could see some melting of snow initially, the fact that temps will remain below freezing until Wednesday afternoon, any melting that does occur should lead to refreezing and icy roads.
An upper trough will dig into the Central Plains on Monday, with a surface low moving into the Great Lakes region. A cold front trailing south of this parent low will make its way eastward and arrive into
the Mississippi River by sunset on Monday. Ahead of this, southwest flow through the vertical column will begin to filter moisture northward and into the TN Valley. Given ample sunshine and WAA,temperatures will feel quite warm, with highs in the mid to upper 50s during the day. A secondary piece of energy dropping SE out of the northern Rockies and into the ArkLaTex region will trigger pressure falls over southern MS/LA and a weak surface wave is progged to develop. This secondary wave will work in concert with the parent upper level trough to increase vertical motions over the area between 06-12z Tuesday and coincide with our best chances for snowfall.Thinking snow could start as early as 06z in NW AL and be coveringmuch of the TN Valley by 09z. Then as the front and upper wave shift E/SE expect snow to end from NW to SE after 12z Tuesday.
South to southwesterly winds ahead of this feature will allow forPWATs upwards of 0.75 inches to advect into the area. While notoverly anomalous for this time of year, these values are on thehigher side for a winter weather type of an event. As the forcing tied to the features mentions above overspread the area, expect a band of rain to develop as early as 9 PM along the MS River and W TN. Then as the Arctic front and secondary trough shift south this bandof precip will move into NW AL. Forecast soundings suggest that enough of a warm layer will exist near the surface to keep this initial band of rain in liquid form. However, the strength of the Arctic front will send temps quickly below freezing early Tuesday morning and we can expect a rapid transition to all snow. Ensemble probability guidance has shown high confidence in receiving at least a quarter inch of QPF but low probability of anything more than 0.5 inches. So, have adjusted our QPF based on this thinking and values come in around 0.3 inches. Not all of this will be falling as snow and it`s possible that up to 0.1 inch could fall as rain before the change over. Snow ratios will be close to 10 to 1 and that puts snowfall amounts on the low end at 1 inch and on the high end 2.5 to 3 inches.
While the speed of the front might limit the overall length/time period for snow, time-height analysis from various data sets were all indicating a stronger vertical motions either in the dendritic snow growth zone or just below. This would suggest the potential for some brief heavier snowfall rates in any mesoscale banding that develops. Total snowfall plumes from various data sets were trending the mean snowfall towards the 1.5 to 2 inch range. Our current forecast fall inline with these values with some locations in southern middle TN receiving upwards of 2.5 to 3 inches.
These amounts occurring either just before or possibly during the morning commute on Tuesday has prompted the need for a Winter Storm Watch to highlight the potential for travel impacts. Even though we could see some melting of snow initially, the fact that temps will remain below freezing until Wednesday afternoon, any melting that does occur should lead to refreezing and icy roads.
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accu35
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I've seen heavy snow few years back in TN that put down at least 1" in 45 min. It was a fast mover also
For the non Zulu type, what time is this hitting ATL?
Noon.
In all fairness, Daytime temps at the time were in the teens and 20s (it remains to be seen if that happens again).
That said, it's a lot harder to melt a thick sheet of ice than snow. Plus, the relatively deep/wet snow pack on top of that ice limited the extent of heating from the sun.