Dan The Weather Man: Talking Climate and Weather

 Oh She Trouble...    Ahhh.. Yes, the good old fashioned severe weather season has returned. After a rather quiet April, it seems Mother Nature needs to remind folks who's boss as she takes aim at the Midwest and MidAtlantic today, tomorrow, and on Saturday. In particular, its looking like tomorrow may bring her worst as parts of Kentucky, Tennessee, Illinois, and Indiana and others prepare for damaging winds, large hail, and tornadoes. The Storm Prediction Center (SPC) has outlined these areas in a Moderate Risk (Level 4/5) for the possibility of widespread, long lived severe weather with portions of the MidAtlantic (including Virginia) being outlined in a Slight Risk (Level 2/5).  SPC Day 2 Categorical Risk. Severe Weather is most likely over the Moderate Risk area, which encompasses Missouri, Illinois, and Kentucky  The Setup:  A potent shortwave trough and occluding, strong low pressure will slowly eject over the Plains and upper midwest over the next 4...

           We've all heard our friends, family, and even meteorologists discuss how "heavy" the air feels during humid summertime afternoons in RVA. How many of us have also jokingly said that we could "wear the air" on those particular days? Well I hate to burst your bubble....but you've been lied to...  warm, humid air is actually less dense or "lighter" than drier air. How can that be?! Well...           This is due simply to the presence of water vapor, which has a smaller molecular mass by particle than the same particle of dry air. This can be explained by a simplified example: Let's assume for a moment that dry air is only composed of pure oxygen molecules (O2). O2 has a  molecular weight  of ~32 amu (16x2). Water vapor, H2O, is composed of 2 Hydrogen molecules and 1 Oxygen molecule for a total amu of ~18 ((2x1)+16=18 amu). But what about Nitrogen (N2), which makes up around 78% of the  atmospher...

           With the warmer temperatures and severe weather season well underway, you may have heard me or other meteorologists mention the term "Inverted-V."  Unless you happen to be a weather geek like me or decided to google it after reading this, you've probably thought to yourself "is he talking about a mega wedgie"?            No I swear, the Inverted-V isn't another name for a wedgie...it is another way meteorologists describe an atmosphere that features relatively drier air near the surface. More specifically, the name originates from weather soundings that feature larger temperature-dewpoint (dewpoint depressions) spreads near the surface compared to the atmosphere, which resembles an inverted-v shape.  An Inverted-V Weather Sounding (Depiction of Atmospheric Conditions) Courtesy Of  wasatchweatherweenies . Red line is temperature and green line is dewpoint. As seen in the sounding, the red and gree...