Sunday, March 6, 2011

March 7, 2011 Forecast

Tomorrow, we can expect the low pressure begin to strengthen over the north Texas area, igniting the snowstorm expected for Nebraska and parts of Iowa. Especially heavy snowfall will occur in West Nebraska, where the heaviest snow totals can be expected.

The Midwest can expect clouds in some areas as a cold front begins to come down from the Upper Midwest.

A trough off the coast of Florida will likely create some clouds or spotty sprinkles with clouds in some areas.

Strong low pressure will continue moving east. Precipitation will continue throughout much of the day for the north part of the Northeast.

Mountain precipitation will occur, as will clouds with the high elevation precip and low pressure off the coast. Would not be surprised to see rain showers in the area.

High elevation precipitation will continue. Lower elevations should have a mostly sunny day, but with close-by low pressure, will include clouds in the forecast.

Trough moving through, which is the beginning of the cold front, will create clouds and sprinkles of rain.

Severe Storms March 7-10 2011 Overview

A cold front on a strong low pressure will be dragged across the South, potentially igniting severe thunderstorms. This is an overview to accompany that situation.

First, we will start off with the overall threat of severe storms. The Storm Prediction Center issues daily outlooks for severe weather.
There is a slight risk for severe thunderstorms in east Texas into much of Louisiana and Arkansas. Also included in this risk is Southeast Oklahoma.
Below is the percentage risk for severe storms.
The 15% risk covers the slight risk area listed above, with 5% risk in Missouri, Southeast Kansas, more of Texas and Oklahoma, along with Mississippi. West Kentucky and West Tennessee are also in the 5% risk, along with South Illinois.
I do anticipate the cold front to produce severe storms, especially across the 15% range and the Gulf Coast, closest to the open warm, humid air of the Gulf.

Next, we will see the temperature differences forecast to predict how strong these storms could be.
In the above image, it does appear dry, cold Arctic air will be toe to toe against pure warm, humid Gulf air. This definitely is a bad set-up in the way of damaging storms, and will have to be kept a close watch on.
The Weather Centre will continue watching this closely and bring you more updates as they progress.

Winter Storm March 7-10 2011 Overview

A strong low pressure is expected to form across the west US and track into the Midwest and Great Lakes. This is an overview of that storm.
First, we will start out with who will get what form of precipitation. Below is an image from the GFS Ensembles.
The bold blue line is the freezing temperature in the clouds. We see the blue line close to this low pressure system. People below this blue line are projected to get rain, while people above are expecting snow.
At this time, The Weather Centre is toying with the idea of that blue line wrapped closer around the low pressure system, but for now will go with the image above.

Next, we will get an idea of how strong this low will be. It will be carrying a cold front, which will likely introduce severe storms. However, we will talk about the severe storm part in the next post. Below is from the latest GFS Ensemble to get an idea of how strong the low will be, or at least how windy it can get.
In the image, we see the low centered around North Illinois. The tighter the isobar lines get by the low is the windier it will be. So for people in Iowa, Wisconsin, Indiana, Missouri, Michigan and anyone else in those tight lines, expect very windy conditions in your area come midweek.
The storm itself doesn't look to be incredibly strong, with a central pressure of around 1001 millibars. It will definitely produce sufficient precipitation, but lows above 1000 millibars are typically on the weak side.

Finally, we will take a look of how much precipitation can be expected. The reason I use the GFS Ensemble images is because they make up the GFS images.
People in the rainy section of this low are going to be under quite a flood threat. After all the saturation of other rains, this will only worsen the flooding problem. Below is the GFS Ensemble image for 72 hours precipitation.
So we definitely see some intense precipitation across the Plains into the Midwest and Great Lakes. Anyone in the .5'' + area should be prepared for minor flooding.
The Weather Centre will continue watching this situation unfold.

Winter Weather Situation #001

At this time, there is a risk of fairly high freezing rain rates from East New York down through East Pennsylvania. The risk also includes much of Vermont and Kentucky.
In that risk, freezing rain rates of up to .05 inches an hour are possible, possibly more.
Watch out for icy spots if you live in the Northeast.

Potential For Snowstorm March 7-10

Good morning all. I just ran the models, and here's what they had to say.
The WRF model is taking a track through North IL with backside snows. The main precip will be rain however.
12z GFS: A tad faster than WRF.
Since the 12z models aren't up yet, I will provide information on the earlier runs then comparisons.

0z ECMWF: Takes the low through the WI/IL Border.
0z NOGAPS: Takes the low a bit farther north than the ECMWF.
0z GEM: Takes the low far north and west than ECM/NOGAPS