First of all, I do not intend this blog to be a severe weather blog, but the weather around here lately has been boring.
The term "Dixie Alley" gets tossed around a lot this time of year and it is never really defined beyond that. For those that aren't aware/aren't severe weather junkies, I just to briefly define it. "Dixie Alley" is essentially just a an extension of the traditional tornado alley into the Southeast and lower MS River Valley. In the late Winter and early Spring, the dynamics of
Some type of severe weather threat is appearing more likely around the Saturday time fame from KS down into northern TX as a low develops on the flat side of the Rockies and works to setup/organize a dry line and triple point region.
As the system pushes east, there is the potential to have a respectable cold front kicking into a moderately to highly sheared 60F+ Td warm sector along the MS River/Dixie Alley.
Obviously too early to start boarding the train, but there is def potential for this
Generally light snow overspread Connecticut from west to east during the morning on January 28th. Snow continued into the early afternoon and at the same time, warmer air moved in aloft. A change to sleet and freezing rain occurred from southwest to northeast, with portions of the I-95 corridor changing over to plain rain.
Precipitation tapered off to intermittent drizzle with freezing drizzle across much of the interior by early evening.
Snowfall totals were fairly uniform with most areas pic
Eventual tornado threat will depend on how unified the current line of storms becomes. If it can manage to maintain some semi-discrete updrafts within the line, then all current data points towards a significant nighttime outbreak across AL/northern LA/western MS. The combination of boundary parallel upper SR winds and low level SR winds on the order of 20-40 knts has me personally a little worried about a too unified squall line ATTM for a significant tornado threat.
Some guidance manages to k
Severe weather outbreak looking more and more possible across portions of the lower Mississippi Valley and deep south tomorrow and tomorrow night.
This evening the culprit low is located across western Kansas with a warm front stretching along the Kansas border and into northern Missouri. The dryline is located from west of KICT down through western Oklahoma and Texas … roughly along a line from Altus, OK to Sweetwater, Texas and then southwest from there. The cold front is lagging behind in fa
I expect light snow to reach the NY/CT and NY/MA border around 9 a.m. or so and then overspread the area from west to east. The heaviest precipitation amounts impact northern Connecticut into central and western Massachusetts.
Quick warming at 850mb should push most areas over to sleet and freezing rain. The cold layer aloft up to about 925mb looks deep enough where the inland hills may get a thump of sleet, while the interior coastal plain could see several hours of freezing rain.
By late aft
An area of low pressure with move out of the plains and up to our Northwest. As it passes by, it will drag a fairly healthy cold front across the area Wednesday afternoon/evening.
It is only January but strong winds just off the surface leading to strong shear, a good quality warm sector, and linear forcing with the front may be enough to trigger a strong to severe line of forced convection along the cold front. The primary threat would be damaging winds and heavy rainfall with PWATS possibly
I eluded to the severe weather threat briefly in my more board centered post on the freezing rain/sleet potential a bit ago, but I thought that it deserved its own post given that it may be first real large (on an area scale) event.
Area of interest is to the right of a line from the Akrlatex region to southern Indiana/Illinois to Western TN to the Gulf.
The same synoptic trough out west that helps to setup our boundary will also be responsible for driving a low from the central plains up towa
A warm front associated with the next system out west will cross the area Sunday night/Monday. The associated precipitation is expected to be very light ... with well under 0.25" very likely. Cold air at the surface looks marginal, with upper 20s at the lowest and with southerly flow around high pressure to the East, that will be kicked out fairly quickly IMO. Any precipitation that does fall will be in the form of sleet and freezing rain initially, with precipitation after roughly 13z likely
Somewhat higher confidence in the QPF totals brought about an expansion of the 2-4" area. The GFS/NAM continue to suggest a snow hole in the northern VA and DC region, which remains a slight risk to the low side. Overall, I think risks are more to the high side, with localized 2-4" totals possible within the 1-2" contour. Likewise, the 2-4" contour could see localized totals of 4-8" (which is more so for the Appalachians than anywhere else).
This isn't really a big event, but due to the amount of discussion it's had, I felt a map was warranted.
Low pressure moving through the Great Lakes brings an usual push of generally light snow towards the Appalachians. A new area of low pressure is forecast to form east of the mid-Atlantic region, enhancing snowfall amounts ever so slightly around the coastal plain. This map does not show it, but light snow should extend southward into Virginia.
I believe that most areas will see an inch or l
Certainly a new breed of winter storm for this winter as we now have plenty of cold air in place, but moisture will be lacking in most areas. The good news is most of the Mid-Atlantic will see high snow ratios around 15-20:1, giving the event more bang for the buck.
Risks are more to the low side at the moment, with the current forecast leaning more towards the wetter European solutions. The NAM and GFS have been fairly insistent on a DC snow hole where accumulations are less than an inch. Whil
Hail can be a weather enthusiast delight during the Summer time (perhaps it reminds them of snow?). Unfortunately, forecasting hail size can be a bit of challenge.
One method that I use is VIL Of the Day (VOTD). It was developed by the NWS back in the 90s. It purely relies on temperatures aloft and while simple, does a surprisingly good job. Obviously there are some limitations, but I will get to those in a minute.
The calculation is straight forward and is as follows:
VOTD = 750 / [(h5T+h
The Quasi-Biennial Oscillation (QBO) as defined by the AMS:
The QBO provides a good first-order look at the background state of the stratosphere, which can be significant for seasonal prediction. It's reliable periodicity (probably the most consistent atmospheric oscillation known today) also makes it a useful tool in forecasting.The QBO is measured by the anomaly of the winds at 30mb averaged along the equator. Here we run into the problem which is the joy with which people embrace one-dimensi
Stuck in northwest flow for the next week, any current weather discussion here at OU has not been able to escape the use of the word "boring". However, a change is gonna come.
One of the distinct characteristics that I'm seeing of the pattern over the next week is that within this wave system, the sub-polar vortex over eastern Canada and the Northeast overwhelms the ridging over western North America. I compared it to RKW theory and the balance of vorticity in the system ... In this case the st
Thanks to some feedback, I cleaned up this map and added a few additional reports.
There are still some gaps in Litchfield County, a report of 4.0 inches in Torrington made more sense based off of observations and radar imagery for that area. You can see how the higher amounts were generally confined to the higher terrain, with lower amounts in the Conn. River and Shetucket River valleys.
Below is a color, contoured map I put together:
A quick update before I head into work... shifted the forecast further south overall and tightened up the contouring in areas that have slightly higher confidence than the initial forecast.
This results in a virtual no-show north of DC aside from some flakes in the air to a dusting. Southern VA into northern NC will get rocked as the vort. max pushes through. There is a risk of this shifting even further south according to some of the hi-res models.
The image is comprised of snowfall totals from various sources, some of which include the New England forum on here. Snowfall totals across Connecticut were pretty uniform around 3-4", although slightly lower amounts occurred along I-95 and there were a few isolated amounts around 5".
I'll post a contoured color map within the next 12 to 18 hours.
Here comes the first notable snow event for the southern Mid-Atlantic this winter! A powerful upper-level vort. max will push through the region tomorrow, bringing strong dynamics with it that will help create a period of moderate to heavy snowfall. The snow will start in the morning hours in the higher elevations and will work east through the afternoon and evening. The I-95 corridor will probably start off as rain in the morning. Some sleet could accompany the transition in the late morning an
Surprised I haven't seen any discussion about this bomb on the board.
Check out the DT pressure map I attached below. You'll never see a better signature of a tropopause fold. And obviously all sorts of upper level support with massive divergence aloft.
From Ryan Maue:
I see this event as a widespread 2-4 incher across most of interior SNE. The tough call comes along I-95 for BOS-PVD-GON, as often is the case. I do think most areas even along the South Shore get a thump of snow/sleet at the beginning.
I'm not really all that confident on widespread 4"+ amounts, but I've outlined an area with a black dotted line that could see locally 5-6 inches.
I also expect precipitation to quickly shut off in the morning (by 7 or 8 a.m. across much of Connecticut) and ta
This latest easterly QBO period is on track to become the "strongest" episode on record. Below I have plotted the QBO along with an integrated QBO index which very simply sums the monthly QBO across each full easterly period.
So far this current -QBO period has an integrated magnitude of -280.62 ... which falls just short of the 2001 -QBO period with a magnitude of -280.79.
The mean is -191.6 and standard deviation is 48.6.
Data so far for January 2013 suggests the monthly QBO should come in
Very tough call on the southern edges of the contours as sleet and freezing rain make an appearance as far south as northern MD (not including the mountains).
Some locally higher totals of 4-8" are possible, and I put a 4-8" contour area in the spot where I think that is most likely to occur. Ratios should be above 10:1 at least at the start of the snowfall across northern PA before the warmer mid-level air tries to nose in.
