First blog post.
Welcome to my weather blog! Here I will cover any storms that have the potential to impact population centers across the central and eastern US, as well as occasionally post about the long range pattern.
There is some severe weather ongoing currently. Instead of jumping in and Monday morning quarterbacking this outbreak, I will advise you to go to weather.gov to view the latest severe warnings directly from the source, the NWS, and to visit spc.noaa.gov to view the latest convective outlooks from the storm predication center.
First order of business is a storm that is currently producing the severe weather over the eastern Plains, and is spreading a swath of snow and ice from the northern Plains towards the Great Lakes. Weather.com has a great interactive radar map with precipitation types, so I will advise you to visit that radar for a current look at where it is raining and snowing.
Above is the heavy snow risk (4”+) from the hydrometeorlogical prediction center valid from 8pm eastern daylight time Tuesday evening through 8pm eastern daylight time Wednesday evening. Right now the expectation is that with a strong 50/50 low developing over southeastern Canada, the storm will be forced southeast as cold air pours in on the northern side. Right now the expectation is that the heaviest snow, 8-12” will fall over the upper Mississippi Valley, with amounts slowly decreasing as the storm is suppressed off to the south as it heads east.
A quick look at the ECMWF model for 8am Wednesday shows the large upper level low over eastern Canada that will force the storm south. Note how there is a good amount of moisture (green on the bottom two images) north of the 5000 foot above sea level freezing level (solid black line in bottom right image). This indicates snow from this line points north.
Note how by 8am EDT Thursday morning the storm is moving off the east coast, with colder air pouring in behind it switching things over to light snow showers potentially as far as Philidelphia and the northwest suburbs of DC/Baltimore, which is fairly far south given the time of year. Any accumulating snow should be confined from central PA and northern NJ points north, with NYC possibly picking up a sloppy 1-2” of snow Wednesday night into Thursday morning.
As we move forward, the focus will shift towards a storm system expected to eject east out of the Rockies at the beginning of next week.
Above is the ECMWF model valid 8am EDT Monday morning. There are a few features I want to point you to on the upper level forecast, in the upper left corner.
The first feature is a large, blocking ridge of high pressure near Hudson Bay in Canada. This, along with higher heights over Greenland (which is just off the edge of the image) will pin feature number two, a “50/50 low” over southeastern Canada. This is going to flood much of the northern US with cold air from the Rockies east. Note how the 5000 foot above sea level freezing line (solid black line) is well south in the bottom right image. This sets the stage for feature number three and the “southern stream energy” to eject from the western US.
What determines how strong of a storm occurs, and where it tracks, depends on if feature three phases, or combines with the southern stream energy. The southern stream energy will be very slow to move east, and feature three is riding in on a strong Pacific jet (note the tightly packed height lines off the west coast in the upper left panel), however is running into a ridge. If feature number three has enough momentum to continue pushing east, it may phase with the southern stream energy and result in deepening of the storm as it moves towards the Ohio Valley. In addition, the lobe of energy sinking south over the Great Lakes above may combine with feature three and the southern stream energy to help with the phasing process.
The most aggressive model, at the moment, with phasing this storm is the Canadian model, or GGEM:
The GGEM is in the process of phasing the pieces of energy in the above image, valid for next Tuesday morning. Note how the model has a deepening area of low pressure over the lower Ohio Valley (upper right image) and how the storm is closed off at the upper levels. This results in a large area of precipitation breaking out from the east coast back into the central Plains, where the model is printing out a significant amount of snow over parts of NE, KS, IA, MO and into IL.
The ECMWF model is less aggressive in phasing this storm. Note how Tuesday morning the ECMWF model is weaker and farther southeast with the storm than the Canadian model. The model is still printing out some snow over parts of the mid-Mississippi Valley, but wouldn’t be as impressive as the Canadian model.
The ECMWF however, due to being less aggressive with phasing the storm, shows a storm track farther south, and waits to blow up the storm until it reaches the east coast. This would result in a major late season Nor’easter over the Mid Atlantic and New England, and a major snow storm for the big east coast cities.
The GFS model on the other hand is significantly less aggressive with this storm and shows little if any phasing. This results in a non-event, with only some light rain breaking out over the southern and flurries in the colder air farther north.
So, what gives? Which model is right?
Essentially at this point in time, the models have some slight disagreements at the upper levels, which results in significant differences in their handling of the storm. At this point in time it is nearly impossible to speculate which model is right with this storm, however we can draw a few conclusions:
- If the southern stream energy phases with energy moving in from the north is critical. No phasing=no major storm, while strong phasing could result in a strong storm cutting as far north as the lower Great Lakes.
- There is some disagreement among the models on the handling of the 50/50 low over southeast Canada. This may affect how far south the models bring the northern stream energy, which would affect how much phasing the models show.
- Either way, with a strong 50/50 low being shown on most if not all models, any storm that occurs in this time frame will likely occur farther south than the ongoing storm, which would spread snow/ice farther south, possibly into parts of the upper OV, Mid Mississippi Valley, and potentially portions of the Mid Atlantic.
- Any storm would affect the central US Monday-Tuesday, and the eastern US Tuesday-Wednesday.