Saturday, January 29, 2011

Predicted Snowfall Estimates (Feb. 1-3)

GFS: 10-12'' (At least 6'')
ECMWF: 1-3' (At least 6'')
NAM: Following ECMWF (At least 6'')
GEM: 8-12'' (At least 6'')
JMA: 3-5''
NOGAPS: unknown

Model Consensus: JMA model is a strange run, will discount it due to drop in snowfall estimates.
NAM and ECMWF are set on a very strong storm that could allegedly produce up to 3 feet in spots.
The GEM is forecasting 8-12'' and is reportedly trying to move north towards the ECMWF/NAM solution.
GFS solution is the most consistent, but with models and ensembles moving north, it is expected for at least a slight shift north in the GFS track.

MIDWEST FORECAST DISCUSSION #1 FEB. 1-3RD


MODEL FORECASTS
-------------------------

The ECMWF model has moderated itself and is now tracking through South IL.
The DGEX model has pushed northward and is now going through Central IL.
The GEM starts to go north, then suddenly drops to the Gulf Coast and continues on a very changed track.
The WRF, although still too far out in the time frame, says that early indications point to a northerly track.
The GFS says the storm will track along Tennessee moving Northeast.

HPC gives out high QPF rates

Much more interestingly, though, is a couple things for North IL/South WI
1. GFS predicts at least 6'' to fall- currently trending towards 8-12''.
2. ECMWF QPF says 1.75'' to 2'' of snow (17-20 inches of snow!!)
3. HPC QPF image above indicates at least 5-7.5'' of snow.

Model Consensus: A professional meteorologist mentioned that storms like these, although currently tracking south, often track north in the end.
Evidence of that happening is seen in the latest NCEP Ensemble, where all members are north of the 6z GFS.
The ECMWF may be trying to think ahead and stay north in event that the north track does happen.

Friday, January 28, 2011

Notice

The following changes will occur:

The following things will be deleted:
-Winter Storm Page

The following things will be modified:
-The Severe Weather Outlook will now include the 2011 Tornado Forecast.

February 1st-2nd In-Depth Analysis



This is a special in-depth Analysis for the February 1st-2nd winter storm.
This is a very in-depth, and long, analysis, so you can zoom down to find a summary. However, the most detailed information will be found throughout the analysis itself.

We're going to hit it right off with an image from the Climate Prediction Center. This is a map issued today, outlining the projected hazards over the next week or so.
We can see a band of heavy snow extending from the Central Plains back through the Midwest and Southern Great Lakes into New England. A line of icy conditions in the same period will be in the Oklahoma area extending through the Southern Midwest and into extreme south portions of the Northeast.
A heavy rain period in the same time frame will be over the South-Central US and portions of the Southeast US.
This storm will be so significant, the entire east US will likely be affected by this storm. It is projected to be very strong.
The Heavy Snow band outlined above is an area I want to highlight. Due to how strong this storm could be, snow totals may exceed 6'' in many places, possibly touching 12''.
The Heavy rain area will be a benefit for drought conditions, which may improve.
But the most concern is the icy strip in the central US. In the below map made by The Weather Centre, I outline a new map, the Danger Map.
While the above image isn't set in stone, there is certainly a risk for danger for ice in the South Midwest to the Southern Plains and the South Central US. Parts of the the Northeast will also be in the ice danger risk at this time.
The heavy snow risk, while not as dangerous, is still a hazard. I predict that the heaviest totals may occur there, with isolated/scattered totals of 10-14'' of snow. Again, this is a far way out and is subject to change.
Below is the expected precipitation map from The Weather Centre.
I did stretch out the moderate snow areas on this precipitation map but drew back the heavier snow areas. I included the icy conditions where ice should be the most dominant precipitation.
Rain will be in place across most of the East US, but the heaviest may be north of the Gulf coast, where the drought is not as severe.
However, these will all be junk if the storm track changes. So, without further ado, I give you a preliminary look at the expected storm track for this storm.
Please realize, and I emphasize this, the storm track is a track that I have been the LEAST sure of in all my days of forecasting.
You can see how big the uncertainty area is as soon as the low gets to the South Central US.
You can take your own opinion on this, but I would take something around the line I outlined.
The track is comprised out of all the major models. Below is a VERY PRELIMINARY snow forecast for this storm.
While these totals are subject to change, I am confident in, at least, a 1-2'' range in the 2-5'' area on the map. After that, confidence drops off rapidly.
Again, returning to the main concern, is freezing rain and sleet, which comes to the risk of icing. This is a VERY PRELIMINARY IceCAST below.
I have outlined an area of severe icing potential as well as a potential for up to .25'' of ice.
I heavily stress that if you are in the danger of severe icing area, PLEASE keep up to date on all weather updates. Whether from The Weather Centre or somewhere else. This could be deadly in those areas.

Summary: Severe icing could occur in the Central Plains west to the East Coast. Heavy Snow is possible north and heavy rain south.

Possibility of the Feb. 1-3rd storm tracking farther north

This is a question i first asked myself.

Looking at various models and ensembles, I have concluded that the possibility for the storm firing north is a potential, but not as much as it would be to be favorable.