It looks like another in a long line of disturbances to affect the region later tonight. I will be reviewing the 36 hour NAM forecast or the 6z run as the graphics become available this morning. For me, this will be about as accurate as the NAM will be.
Also, I am excited about looking at the next run of the Euro. The last run on day 6 shows low pressure developing along the Gulf coast and riding up the east coast by day 7. This has BIG snow written all over it. It looks as if Kentucky will get in on some of this action. The best location for highest accumulations looks to be along and east of I-65, especially eastern KY. Remember, I like the Euro at 6-7 days out. I don't even look at the GFS until day 5 and that's just to compare the tracks of the models. I believe the Euro handled the ice system quite well at 6 days out.
More updates on these two systems later on this page.
==========================
9:55am UPDATE
I've reviewed the 06z/07 run of the NAM
As expected, this looks like a nuisance snow for some of us. I will not be including any future runs of the NAM in the short term from here on out except to compare them to the short term models like the Rapid Refresh Model. The NAM has a history of overdoing QPF amounts and sometimes undercutting them within 24 hours.
Generally snow accumulations of 0.5" to 1.5" will be common, especially south of I-64.
Here are a select few locations:
Louisville 0.6"
Lexington 0.8"
Bowling Green 1.3"
I will say that this forecast from the NAM may have a measure of bust potential as snow to liquid ratios appear relatively high like 14 to 16:1. Therefore, some of these totals may have to be adjusted upward but still think most locations will not get out of a range of 1-3".
However, will be following the next several runs of the NAM as a system dives in Saturday night/Sunday morning, which may produce a quick-hitting large swath of snow mainly along and north of I-64, that may bring a couple more inches of accumulation for some.
Next, I'll be studying the latest Euro run for the storm system that may potentially impact our region mid-week.
MS
Friday, February 7, 2014
Thursday, February 6, 2014
What to Expect the Next 14 Days (Feb 5 - 19)
Cold. That should about sum it up.
I've analyzed the 500mb forecast for the next 10-14 days and a persistent pattern will be prevalent.
This is different than the pattern we saw for much of January, when the Arctic region and Alaska were much above normal regards to temperatures. In addition, the Pacific Northwest felt the effects of the ridge. Our region was impacted as cold air dove deep into the nation's midsection, producing Arctic outbreaks.
There will still be a good deal of ridging along the Pacific coast. Also, there will be an impressive ridge near Siberia. However, there will also be a broad cyclonic flow near Alaska, with stormy conditions.
So, the cold air will be coming from Siberia, thanks to weaker winds associated with their ridge, through Alaska and the Arctic into the Great Plains, which promises to produce very cold readings over the next several days. Therefore, which would you rather have? Arctic or Siberian?
The only saving grace for this period will be the higher sun angle which may help mitigate or modify the cold air intrusions from the north. Still, single digit temperatures could still exist in our region, even by the middle of the month.
And what about that sunlight to help modify our temperatures? The next two weeks should be characterized by active weather patterns. With below normal temperatures expected, we could be looking at an onslaught of precipitation, yes, wintry precipitation as well.
Arctic Oscillation is expected to go negative, very negative.
PNA will be mostly negative as well.
While this setup is generally not favorable for a big snowmaker in our region, the placement of the trough relative to the Alaskan coast coinciding with a Siberian ridge funneling cold air across the Arctic regions diving south into the United States may produce interesting storm tracks here in the U.S.
Where those storm tracks interact with the cold air in place will determine who gets heavy snowfall and ice. This should be an interesting , if not wild weather pattern setting up for the next several days, or should I say a continuation of the wild weather pattern.
Old Man Winter looks like he's going for the knockout punch. Stay tuned.
MS
I've analyzed the 500mb forecast for the next 10-14 days and a persistent pattern will be prevalent.
This is different than the pattern we saw for much of January, when the Arctic region and Alaska were much above normal regards to temperatures. In addition, the Pacific Northwest felt the effects of the ridge. Our region was impacted as cold air dove deep into the nation's midsection, producing Arctic outbreaks.
There will still be a good deal of ridging along the Pacific coast. Also, there will be an impressive ridge near Siberia. However, there will also be a broad cyclonic flow near Alaska, with stormy conditions.
So, the cold air will be coming from Siberia, thanks to weaker winds associated with their ridge, through Alaska and the Arctic into the Great Plains, which promises to produce very cold readings over the next several days. Therefore, which would you rather have? Arctic or Siberian?
The only saving grace for this period will be the higher sun angle which may help mitigate or modify the cold air intrusions from the north. Still, single digit temperatures could still exist in our region, even by the middle of the month.
And what about that sunlight to help modify our temperatures? The next two weeks should be characterized by active weather patterns. With below normal temperatures expected, we could be looking at an onslaught of precipitation, yes, wintry precipitation as well.
Arctic Oscillation is expected to go negative, very negative.
PNA will be mostly negative as well.
While this setup is generally not favorable for a big snowmaker in our region, the placement of the trough relative to the Alaskan coast coinciding with a Siberian ridge funneling cold air across the Arctic regions diving south into the United States may produce interesting storm tracks here in the U.S.
Where those storm tracks interact with the cold air in place will determine who gets heavy snowfall and ice. This should be an interesting , if not wild weather pattern setting up for the next several days, or should I say a continuation of the wild weather pattern.
Old Man Winter looks like he's going for the knockout punch. Stay tuned.
MS
Tuesday, February 4, 2014
Nowcast BIG Storm
Well, this was supposed to be the BIG storm. It's gonna be big for some in our region, however.
A mixture of rain, sleet, freezing rain, and snow. It's all in there, what is called a grab bag of precipitation.
Using the latest RAP short term model and weather observations upstream, this page will be updated frequently during the day.
I will focus mainly on Louisville but may include areas like Lexington and southern parts of Indiana as well.
6:30am
09z/04 run of the RAP shows at the 850mb and 925mb levels liquid precipitation for the most part above Louisville by 5pm. Surface temperatures will become critical by this time. At the onset, a mix of snow, sleet, and rain will be possible for Louisville. However, after a couple of hours, rain and pockets of sleet will dominate the next several hours through 10pm. If surface temperatures remain at or below freezing, accumulation of ice will become noticeable, at least 0.1" by then.
=====================
9:45am
12z run RAP continues to show precipitation moving into the Louisville area between 4 and 5pm. It may start out before then but main shield should hold off till after 4pm. By midnight, total frozen precipitation could reach 0.44". That will not be good if it's all ice. But, it looks like sleet will be mixing in at times. Again, though, temperatures will be key.
Current temperature at my house in Valley Station is 29 degrees.
Interesting side note - The NAM, which is generally the model of choice for the short term, is considered the outlier. Last time the NAM was the outlier, it trumped all of the other models. It shows most of the ice along and just north of the Ohio River.
=====================
A mixture of rain, sleet, freezing rain, and snow. It's all in there, what is called a grab bag of precipitation.
Using the latest RAP short term model and weather observations upstream, this page will be updated frequently during the day.
I will focus mainly on Louisville but may include areas like Lexington and southern parts of Indiana as well.
6:30am
09z/04 run of the RAP shows at the 850mb and 925mb levels liquid precipitation for the most part above Louisville by 5pm. Surface temperatures will become critical by this time. At the onset, a mix of snow, sleet, and rain will be possible for Louisville. However, after a couple of hours, rain and pockets of sleet will dominate the next several hours through 10pm. If surface temperatures remain at or below freezing, accumulation of ice will become noticeable, at least 0.1" by then.
=====================
9:45am
12z run RAP continues to show precipitation moving into the Louisville area between 4 and 5pm. It may start out before then but main shield should hold off till after 4pm. By midnight, total frozen precipitation could reach 0.44". That will not be good if it's all ice. But, it looks like sleet will be mixing in at times. Again, though, temperatures will be key.
Current temperature at my house in Valley Station is 29 degrees.
Interesting side note - The NAM, which is generally the model of choice for the short term, is considered the outlier. Last time the NAM was the outlier, it trumped all of the other models. It shows most of the ice along and just north of the Ohio River.
=====================
Monday, February 3, 2014
Snow Totals
As of 4:00am, snow has nearly exited the Metro area. Minor accumulations are still possible. I have seen reports of snow over 4" widespread for Jefferson County, including my little part in the southwest part of the county.
So far, the RAP model that I use is getting lots of love from my area. It showed an average of 5" for the Metro or 4-6" range. And from reports that I'm seeing, that appears to have verified
J'town and Okolona reports of 6".
I have not seen a recent report from the NWS office in southern Jefferson County yet but sure their total is near 5-6".
Jefferson County schools have just announced they are closed
4.4" in Valley Station
4.0" in Lexington'
5.2" at Louisville Int'l
6.1" at Louisville WFO
6.8" in Shelby County.
Season totals have been updated.
MS
So far, the RAP model that I use is getting lots of love from my area. It showed an average of 5" for the Metro or 4-6" range. And from reports that I'm seeing, that appears to have verified
J'town and Okolona reports of 6".
I have not seen a recent report from the NWS office in southern Jefferson County yet but sure their total is near 5-6".
Jefferson County schools have just announced they are closed
4.4" in Valley Station
4.0" in Lexington'
5.2" at Louisville Int'l
6.1" at Louisville WFO
6.8" in Shelby County.
Season totals have been updated.
MS
Sunday, February 2, 2014
Nowcast...The Big Storm Before the BIG Storm
The current storm system looks to provide plenty of messy issues for many in our Commonwealth. A great deal of uncertainty continues to be factored into even the short term models.
This is where nowcasting becomes important, not just from a short term model aspect.
The most current observations possible will become critical as far as forecasting what may happen to the next tier of counties.
If you have a thermometer, check it.
If it's still raining outside and the thermometer reads near freezing, put on your rain suit, go outside and feel metal objects, observe any ice building up on branches, bushes.
If you hear or see ice pellets bouncing around or pinging, report that as sleet.
If it's snowing, report that especially as soon as changeover begins.
Report if it's sticking to the grass or to the pavement or not at all.
If it's sticking, measure it, preferably in an open area, away from rooftops. Decks do not count, unless you use the one by the pool, which should be away from the house.
If you're traveling, report road conditions as wet, slushy, icy, snow-covered.
Most important, if you're traveling, BE CAREFUL.
This page will be updated frequently, especially as future short term model runs occur. I will be making many references to terms like 850mb, 925mb readings. These are referencing temperatures between 2,500 and 5,000 feet above the surface. This information will prove to be important because if your thermometer reads 32 degrees, yet the 850mb reading is above 32, then it will be likely raining at your location and freezing on contact at the surface.
MS
=====================
4:15am
06z RAP
850mb freezing line just south of Louisville by 7pm
925mb freezing line into central KY
Mix of snow/rain by 5pm with complete changeover by 7pm or so for Louisville.
=====================
5:00am
Widespread Winter Storm Warning products out for our region, including Louisville, Lexington, E'town, and points east into eastern KY.
=====================
5:10am
At Louisville, temperature has dropped from 50 to 39 degrees within the past two hours. It is now 39 at my house as well.
=====================
7:50am
10z run RAP
batch of light precipitation may become freezing drizzle, freezing rain along Ohio River before 3:00pm, maybe even change to s-2now across southern IN.
A brief lull then mostly snow for Louisville by 5pm onward. After dark or a little later, accumulations should begin. By 11pm, at least 2" may be on the ground in Louisville.
=====================
12:40pm
RAP model continues to highlight moderate to heavy snow for the Louisville area, perhaps even shifting the heaviest axis into the area while parts of southern IN could be looking at warning criteria. At this time, 4"+ is looking likely for Louisville. However, this is still a developing storm. Many variables still need to be analyzed and come together. There are indications that a thin stripe of very heavy snowfall could occur with rates -approaching 2"/hr. Therefore, 5-6" are possible between Louisville and Lexington. Still monitoring latest runs. Looking out west for observation data. Temperature remains at 34 degrees at my house.
====================
1:30pm
Heavy snow falling across southern MO like West Plains and Branson. This could be the snow that will impact our area later this evening and overnight. Still looks like Louisville to Lexington could be in for a major accumulation (4-8")
====================
2:10pm
1-2" common across parts of southern MO, falling within the past couple of hours. Numerous slide-offs.
=====================
2:15pm
3" south of West Plains MO. This kind of snow is heading toward the area for later this evening/overnight.
====================
3:15pm
2-4" from Branson to West Plains. Numerous accidents. Sleet falling across Western KY. Sleet reported in Louisville.
Latest RAP continues to paint at least 5" in Metro Louisville. That would put them in a 4-6" range. Nevertheless, Lexington and nearby locations stand to receive perhaps 6-9 inches.
Look for parts of southern IN to go under a warning if this trend continues.
This is where nowcasting becomes important, not just from a short term model aspect.
The most current observations possible will become critical as far as forecasting what may happen to the next tier of counties.
If you have a thermometer, check it.
If it's still raining outside and the thermometer reads near freezing, put on your rain suit, go outside and feel metal objects, observe any ice building up on branches, bushes.
If you hear or see ice pellets bouncing around or pinging, report that as sleet.
If it's snowing, report that especially as soon as changeover begins.
Report if it's sticking to the grass or to the pavement or not at all.
If it's sticking, measure it, preferably in an open area, away from rooftops. Decks do not count, unless you use the one by the pool, which should be away from the house.
If you're traveling, report road conditions as wet, slushy, icy, snow-covered.
Most important, if you're traveling, BE CAREFUL.
This page will be updated frequently, especially as future short term model runs occur. I will be making many references to terms like 850mb, 925mb readings. These are referencing temperatures between 2,500 and 5,000 feet above the surface. This information will prove to be important because if your thermometer reads 32 degrees, yet the 850mb reading is above 32, then it will be likely raining at your location and freezing on contact at the surface.
MS
=====================
4:15am
06z RAP
850mb freezing line just south of Louisville by 7pm
925mb freezing line into central KY
Mix of snow/rain by 5pm with complete changeover by 7pm or so for Louisville.
=====================
5:00am
Widespread Winter Storm Warning products out for our region, including Louisville, Lexington, E'town, and points east into eastern KY.
=====================
5:10am
At Louisville, temperature has dropped from 50 to 39 degrees within the past two hours. It is now 39 at my house as well.
=====================
7:50am
10z run RAP
batch of light precipitation may become freezing drizzle, freezing rain along Ohio River before 3:00pm, maybe even change to s-2now across southern IN.
A brief lull then mostly snow for Louisville by 5pm onward. After dark or a little later, accumulations should begin. By 11pm, at least 2" may be on the ground in Louisville.
=====================
12:40pm
RAP model continues to highlight moderate to heavy snow for the Louisville area, perhaps even shifting the heaviest axis into the area while parts of southern IN could be looking at warning criteria. At this time, 4"+ is looking likely for Louisville. However, this is still a developing storm. Many variables still need to be analyzed and come together. There are indications that a thin stripe of very heavy snowfall could occur with rates -approaching 2"/hr. Therefore, 5-6" are possible between Louisville and Lexington. Still monitoring latest runs. Looking out west for observation data. Temperature remains at 34 degrees at my house.
====================
1:30pm
Heavy snow falling across southern MO like West Plains and Branson. This could be the snow that will impact our area later this evening and overnight. Still looks like Louisville to Lexington could be in for a major accumulation (4-8")
====================
2:10pm
1-2" common across parts of southern MO, falling within the past couple of hours. Numerous slide-offs.
=====================
2:15pm
3" south of West Plains MO. This kind of snow is heading toward the area for later this evening/overnight.
====================
3:15pm
2-4" from Branson to West Plains. Numerous accidents. Sleet falling across Western KY. Sleet reported in Louisville.
Latest RAP continues to paint at least 5" in Metro Louisville. That would put them in a 4-6" range. Nevertheless, Lexington and nearby locations stand to receive perhaps 6-9 inches.
Look for parts of southern IN to go under a warning if this trend continues.
Saturday, February 1, 2014
NAM Model Shunts Snow Band Northward
Wow. I don't know what to tell you. A monumental shift in the expected snow band within 12 hours.
What looked like a decent snow event across most of central and east/se Kentucky has now shifted the heaviest snow band from Louisville to Lexington and E'town while still showing a decent accumulation for eastern KY.
At this rate, I wonder if the NAM is overcompensating already or if the northward trend will continue.
Really tough to nail down expected totals when Ole Reliable (NAM) is got a case of the magic jumping beans.
I cannot imagine Louisville being in line for 2-3" when just a few hours ago, we were talking about flurries.
Time to see what the NWS Louisville thinks about this trend.
MS
What looked like a decent snow event across most of central and east/se Kentucky has now shifted the heaviest snow band from Louisville to Lexington and E'town while still showing a decent accumulation for eastern KY.
At this rate, I wonder if the NAM is overcompensating already or if the northward trend will continue.
Really tough to nail down expected totals when Ole Reliable (NAM) is got a case of the magic jumping beans.
I cannot imagine Louisville being in line for 2-3" when just a few hours ago, we were talking about flurries.
Time to see what the NWS Louisville thinks about this trend.
MS
Preliminary First Call for Snowfall
At at time when most meteorologists have been looking ahead to the BIG system, which looks to bring mostly rain to the Commonwealth, a rather potent winter storm is taking shape and aiming for central and eastern KY for the Sun pm/Mon am time frame.
Using the 06z/01 run of the NAM, here is a preliminary look at snow and ice totals for the region.
Bardstown 1" or less
Bowling Green 1-3"
Corbin 2-4", <0.2" ice
Elizabethtown less than an inch
Glasgow 1-3"
Jackson 2-4"
Lexington 1-2"
London 3-5"
Louisville dusting to 0.1"
Pikeville 3-5"
Richmond 1-2"
Somerset 3-5"
Locations from Whitley to Letcher counties could see rain/ice with decent accumulations of one or both.
I would like to see the runs of the 12z and 18z runs of the NAM to make a final forecast for the region.
The NWS Jackson may want to issue Winter Storm Watch products for east to southeast KY.
A sw-ne line from Russell to Lawrence couties representing the northernmost boundary of the Watch product and nearly all points south of that in Kentucky. Again, standby only.
MS
Using the 06z/01 run of the NAM, here is a preliminary look at snow and ice totals for the region.
Bardstown 1" or less
Bowling Green 1-3"
Corbin 2-4", <0.2" ice
Elizabethtown less than an inch
Glasgow 1-3"
Jackson 2-4"
Lexington 1-2"
London 3-5"
Louisville dusting to 0.1"
Pikeville 3-5"
Richmond 1-2"
Somerset 3-5"
Locations from Whitley to Letcher counties could see rain/ice with decent accumulations of one or both.
I would like to see the runs of the 12z and 18z runs of the NAM to make a final forecast for the region.
The NWS Jackson may want to issue Winter Storm Watch products for east to southeast KY.
A sw-ne line from Russell to Lawrence couties representing the northernmost boundary of the Watch product and nearly all points south of that in Kentucky. Again, standby only.
MS
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