Beyond the 7-Day: Drenching Downpours – We Meet Again

After a few relatively dry days… our luck is changing for the rest of the work week.  A pattern very similar to last week is setting up.  It’s unlikely that we’ll see nearly as much rain as we did last week… but it won’t take as much much rain to create problems because the ground is already quite saturated.

A western Atlantic ridge is creating an upstream atmospheric traffic jam.  A deep long wave trough with three short wave troughs is deepening in the central US.  The result is this “funnel” that moisture can stream through in our direction.  Those individual short wave troughs become important going forward because they will contribute to various periods of rain through the end of the week.  The first potent wave arrives Wednesday evening and it will be capable of producing both a heavy rain and severe weather threat.

The image above is a “Future Radar” snapshot for 7AM Wednesday morning.  These showers/storms won’t be severe but may contain some downpours.  From mid-morning through mid-afternoon, it will likely be mainly cloudy with some hazy sunny breaks.  It’s during this time that we’ll start to build up instability for “thunderstorm fuel”.

The Storm Prediction Center has us highlighted in a level 2/5, or Slight Risk, for severe thunderstorms.  Given the “fuel” and lift from one of those short wave troughs forecast to come through, this seems reasonable.  Most storms will be non-severe… but remember, severe thunderstorms are just a criteria (wind gusts 58+ MPH and/or hail 1″ in diameter or greater).  While most storms won’t contain the damaging wind gusts, ALL storms will carry the risk of drenching downpours as the air will be VERY moisture laden.

The greatest risk with the storms on Wednesday will be for Flash Flooding.  It’s the highest risk because of how saturated the ground is.  Wind is a secondary concern – especially if we can break out into some hazy sunshine for a few hours.  That would kick that risk up a notch.

This map shows the anticipated rainfall through late Wednesday night.  DO NOT take this as Gospel and expect exactly this much rain in these particular locations.  Instead, I present this map to you to show the potential range of rainfall totals.  Generally speaking, those that see the heaviest drenching storms could pick up between 1-2″ of rain.  Outside of that, those that see the more stratiform rain as opposed to the convective rain will generally see under 1″ of rain.

Standard rules apply with Wednesday’s storms.  Keep an eye to the sky if you have outdoor plans AND be sure to keep the Stormtracker 16 App handy in case weather alerts are issued where you live.

Of course – this entire blog was just dedicated to Wednesday’s storms.  Thursday evening, Friday, and Saturday also carry the potential for drenching downpours.  These drenching downpours will finally cut us some slack for the second half of the weekend… but the long range outlook isn’t exactly high and dry.

Stormtracker 16 Meteorologist John Hickey
Facebook:  Meteorologist John Hickey WNEP
Twitter:  @JohnWNEP