Some of the NAM-4km Severe Weather Fields were not being updated due to a bug in the code. This has been fixed. Some of the fields that have been fixed are:
Supercell Composite Parameter
Significant Tornado Parameter
Updraft Helicity Swath
Click on the link below to go to the NAM 4km which is update 4x per day.
NCEP has been running a new version of the GFS for a number of weeks in parallel. Some important changes ahead with the new version, which will likely go into production in May.
The current GFS uses an initialization method called 3DVar, which is an older method of initialization and essentially takes a snapshot of the atmosphere when the model is started.
The new version being tested and will likely be put into production this spring will utilize a more modern method of initialization called 4D-Ensemble-Variation. It is basically a separate model that runs constantly tracking in real-time, changes in the atmosphere so when the GFS run starts it has a much better initialization, in theory.
Verification numbers support 4DEnsVar being a much better solution. The ECMWF has used 4DEnsVar for quite sometime. The CMC Global model and the UKMET and even the Navy NAVGEM have been using a version of the 4DVar for a while now. This will bring the GFS up to par with the other global models in terms of initialization schemes. The 4Dvar and 4DEnsVar are quite computationally expensive and up until recently NCEP didn’t have the computing resources to implement 4DEnsVar. 4DEnsVar is somewhat less computationally expensive, while providing most of the benefits of traditional 4Dvar.
More information about the ongoing GFS parallel testing can be found from this technical note from NCEP released today, with many links to various NCEP sites that have output and statistics from the new GFS developmental model.
Conditions favorable for supercells and tornadoes this afternoon will develop across Central and Eastern North Carolina into Western Virginia. Extremely favorable shear and strong mid-level winds will combine with afternoon heating, to allow destabilization to occur at the time of frontal passage. A broken line of supercells should form by mid to late afternoon across Central North Carolina northward into Western Virginia, These cells will move rapidly northeastward beneath a 100+ knt mid-level jet. The cells will be capable of producing violent tornadoes as they continue into the evening hours. Straight line winds of 75 mph are also possible in bowing segments or in rear flank down drafts. There will be a considerable amount of dry air aloft which will limit the coverage of storms, but will aid the formation of the tornadoes, combined with a low lcl.
Parameters favorable for widespread severe storms from the Gulf Coast northward into the Mississippi and Ohio Valleys. The Ohio and Tennessee Valleys are at the highest risk for widespread damaging winds. Supercells, with a few violent tornadoes are quite likely as well.
Here is a breakdown of the likelihood of severe weather in a given area, starting Wednesday morning continuing through Thursday Morning.
Here are the SPC Storm Reports for the Event:
We are migrating some hardware to a new datacenter tonight (12/19). The homepage, as well as, a few other services will likely be off-line for up to 6 hours.
The following web pages will not be affected by the transition as they are running at the new datacenter.
GFS – Hires
HRRR (Hourly Rapid Refresh)
We will post an updated when all of the migration activities are complete.
We have been busy working the past 2 weeks installing new Dell hardware and configuring our systems in a new data center. Here are a couple of pictures of the progress. We installed 6 new Dell Servers and will have the HP servers installed next week.
We will be switching from the backup GFS processing to the new server cluster this week and will continue migrating much of the current infrastructure over to the new data center.
We appreciate your patience as we switch over to this new hardware and new data center.
Freezing rain mixed with sleet, locally heavy at times, with embedded elevated convection will continue through the overnight into the morning hours across Arkansas and will produce around 1.00-1.25″ of liquid equivalent precipitation. Much of this will fall in the form of freezing rain across Central Arkansas into Western Tennessee. Ice accretion of 3/8″ to as much 5/8″ of an inch are likely before the precipitation finally ends around noon local time. [18Z].
Ice accretion amounts of 1/2″-5/8″ will bring down large branches and some trees. These can fall on power-lines and disrupt electrical service. They can also fall on pedestrians and cars. Ice accretion of this amount can cause widespread disruption of power in urban areas and create life threatening hazards with extended loss of power and falling large limbs/trees.
The area in and around Little Rock, AR is at risk of widespread power outages if the forecast trends continue and ice accretion amounts exceeds 1/2″ later today.
Below.. the total precipitation that will fall as freezing rain as depicted by the HRRR through 22Z. Actual ice accretion will be less due to drip loss.
Click for the latest Little Rock, AR Regional Winter Radar. Updated Every 5 Mins.
The upgraded GFS model went live today. Over the next several days we will be tuning our systems to optimize how we process the new GFS output. The are a number of new variables and higher resolution fields available. We want to make the best use of our resources. You may notice some slight changes in the model graphics or timing of the products for a few days as we make changes in how we process this data.
We are currently working hard to bring on much higher resolution GFS products on our new Linux servers that we just setup. We hope to have the new GFS products available soon for our customers.
Thank you for your patience as we continue increasing our computing capacity and product offering here at Wright-Weather.com
The GFS model will be upgraded tomorrow, 1/14/15. It is under going a major upgrade. The below PowerPoint link will explain in detail the model physics and initialization changes that have been made, as well as, the effect on model performance.
This is a major change to the model and there will likely be new biases and features that we didn’t see in the old GFS due to the higher model resolution. The model is now running at about 13km (near the equator).
We now have several HP DL380 server’s clustered to handle the higher resolution GFS, as well as, HRRR data.
We will have the GFS data in 2 different resolutions. The standard 0.5 degree which have been displaying for years now and soon we will have surface and other 2D fields 0.25 degree.
Look for the higher resolution data in the coming days. The new GFS based model data at 0.5 degrees will begin tomorrow (01/14/15) however, unless NCEP decides to delay the implementation.