Tuesday, 2/2/2016

First, the Wind Advisory…

...WIND ADVISORY IN EFFECT FROM 1 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY...

.THIS AFTERNOON...CLOUDY WITH SCATTERED SHOWERS AND
THUNDERSTORMS. HIGHS AROUND 70. SOUTHEAST WINDS 10 TO 20 MPH.
GUSTS TO AROUND 40 MPH IN THE AFTERNOON. CHANCE OF PRECIPITATION
40 PERCENT.
.TONIGHT...BREEZY. SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS
MAY PRODUCE DAMAGING WINDS. LOWS AROUND 50. SOUTH WINDS 10 TO
25 MPH WITH GUSTS TO AROUND 40 MPH. CHANCE OF PRECIPITATION NEAR
100 PERCENT.

Now, here is the NWS definition for a Wind Advisory…

Wind Advisory

A Wind Advisory is issued when the following conditions are expected for 3 hours or longer.

1) sustained winds of 31 to 39 mph    

AND/OR

2) wind gusts of 46 to 57 mph.

Notice anything unusual?  Yes, the forecast doesn’t came anywhere close to the definition.  And, this is the third time they’ve done this in the past couple of months!

So, let’s put it this way…it’s going to be noticeably windy this afternoon and tonight.  But, Wind Advisory criteria?  Very doubtful.

Severe weather situation

As a massive winter storm moves slowly NE out of Kansas toward the western Great Lakes, a major outbreak of severe storms is expected along the Mississippi Valley late this afternoon into early evening.  The western third of KY and southwestern IN could be hard-hit.  But for the Louisville area the situation is much different.

As is often the case with winter severe storm outbreaks, the dynamics (wind fields, etc) are very strong.  But the thermodynamics (temperatures, moisture, etc) are weak.  Sometimes, the dynamics can overwhelm the weaker thermo and wreak havoc.  That is expected late this afternoon and early evening along and near the Mississippi River.  Severe storms and some strong, long track tornadoes appear possible.

During that time, the thermodynamics will be at their peak.  But, the models never bring any positive thermos into central KY or southern IN.  Any instability dies quickly to our west after 6 P.M.  As the cold front slowly advances eastward, the expected severe storm areas consolidate into the line of gusty winds and very heavy rainfall as it approaches the I-65 corridor.  Biggest threat for our area should be flash flooding.  It’s possible we could see 2″-3″ of rain in a few hours, so watch out for flooding in low-lying areas.  If flooding is going to occur, it should be Midnight or later

As for the timing of the windy, rainy and possibly stormy weather…  For the Louisville area, the primary squally system should pass the area between 10 P.M. and 2 A.M.

Note:

The definition of the severe thunderstorm is Winds reaching 58 mph or higher and/or one inch hail.  I don’t believe either of those items will occur in the Louisville area tonight.  NEVERTHELESS, I do believe a Severe Thunderstorm Warning will be issued locally.  After all, can anybody remember the last time a moderate to strong line the thunderstorms has passed Louisville WITHOUT a warning being issued?  (It’s kind of like that Windy Advisory thing.)

Stuff:

I was happily impressed with the Cardinals win over UNC last night.  Good testament to the character of the team to bounce back from Saturday’s game with UVA.  It also speaks well for a team, such as UVA, that can completely change a game with their exceptional defense.