Monday, September 9, 2013

Ridge of High Pressure Overhead; Hot Week Ahead


Synopsis

Clouds are hanging around this morning due to weak warm air advection above the surface. [EP: an outflow from earlier thunderstorms east of the area  has sparked scattered showers in the metro late this morning, which should wane by early afternoon]. Temperatures have been above average for September [EP: the hottest day of the summer of 2013 occurred yesterday, at 98 degrees!] and are expected to remain so this week. Find out why below, followed by my forecast for the Memphis metro.

Analysis

image
12Z NAM initialized sounding for Memphis, TN. Vertical profile of atmosphere.

Pictured above is an estimate of the vertical profile of the atmosphere at 7 AM in Memphis. The weather model is able to plot this image by processing and interpolating real vertical profiles (mapped by weather balloon launches) from nearby locations such as Little Rock, AR and Jackson, MS. This profile can tell you a whole lot about what is going on within the atmosphere and is one of our main tools as meteorologists. An interesting occurrence that I wanted to point out were the winds, indicated on the far right, at various levels in the atmosphere. They are basically non-existent. There is very little wind to speak of all the way up to the tropopause which is a perfect illustration of the position of the high pressure ridge directly over the Mid-South. Additionally it shows the layer of clouds I mentioned earlier. [EP: I realize this gets a little technical, but hey, the intern is obviously learning something in his Weather & Forecasting class!]

NAM temperature forecast valid Thu morning for the 850 mb (5000') level.
Also shows heights and wind direction/speed, useful for identifying fronts.

The ridge of high pressure is expected to stick around most of the week, with one weather model showing it still directly overhead Thursday morning. This will continue to keep things hot for us while a cold front could be making its way through portions of the Midwest later this week. We should eventually get to experience whats left of the cold front and will hopefully be the topic of the blog later this week. [EP: Go ahead & plan on a much more comfortable fall-ish weekend...]

William's Memphis Forecast

Tuesday: Partly cloudy with a high of 96, low of 76.

Wednesday: Partly cloudy with a high of 95, low of 75.

Thursday: Partly cloudy with a high of 94, low of 75. Slight chance of t'storms.

--William Churchill, MWN Social Media Intern
[Comments by MWN Meteorologist Erik Proseus noted and italicized]

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