Thursday, July 7, 2016  4 P.M.

After the wide model divergence this morning, it’s looking more and more likely as though the short-term models will win out over the big guys (GFS and NAM).  To their credit, the NAM and GFS are rapidly catching on.

Storm Prediction Center has a Severe Thunderstorm WATCH covering about the western half of KY, but it stops short of Louisville.  It doesn’t matter about the watch boundary, because we’re in just as much risk (low) for severe winds as the folks to our west are.  A line of thunderstorms covers southwestern IN and western KY and is rapidly moving eastward – pushing quite strong gusty winds our way.  Radar estimates suggest 60-70 mph winds, but surface results usually don’t match the estimates.  Nevertheless, extreme southern IN and the Louisville area can expect strong (perhaps severe) wind gusts as this line races  through the metro area between approximately 5:15 and 6:30 P.M.  Scattered minor damage and some power outages are likely during that time.

The threat of severe winds from this system drops to near zero very quickly north of I-64.  The above description and timing pertain mostly to the area of IN and KY along and south of I-64.

Thursday, July 7, 2016  11 A.M.

Looking at this morning’s forecast models and actual forecasts is almost a case of “What’s going on?”  Everything you look at has a different story to tell.  First, the NWS forecast includes a scant 20% chance for rain/t-storms today and another 20% chance tonight.  The backbone of our forecast system, the GFS produces a 1% chance today and about 40% tonight (LAMP) and a 4% chance today, 45% tonight (MOS).  Meanwhile, the NAM model output is also low…11% today and 53% tonight.  By the way, all of the “tonight” forecasts call for the rain after midnight.

On the other hand, the Storm Prediction Center gives us a 40% chance for thunderstorms today and just 10% tonight.   Then, the two primary short-term forecasts chime in with a slight different story.  Both the RAP and the HRRR predict a line of thunderstorms to reach the Louisville area between roughly 8 P.M. and Midnight.  Earlier today I saw WAVE TV’s in house model project a line of storms between 6 and 8 P.M..

What’s one to believe?  Good question!  First of all the GFS has been terrible lately as evidenced by a lot of forecasts we’ve heard recently.  Second, the short-term forecasts are better at picking up on the “outflow boundaries” created by previous storm systems, so they should be more reliable.  As a result, I’d lean toward the RAP/HRRR/WAVE forecast expecting a line of thunderstorms this evening.  We’ll see how it plays out.

Latest radar shows single remaining strong t-storm cell in area – just north of the Ohio River in southern Clark Co.  Storm is moving northeast along the river – probably reaching far NE Jefferson Co. and Oldham Co. by 4:50.  Strong, gusty winds possible.  Otherwise, nothing to be concerned about on metro area.

Sunday afternoon

It seems like it’s been a week, maybe longer.  I’ve been warned about a possibility of an ice storm this weekend.  Constant barrages of what we could have – sleet (maybe) rain(maybe), slow(maybe, and freezing rain(maybe).  Starting a couple of days ago, the frozen options began to fall out of the “options” list (as per the computer models),  but not from the forecasts.  If you read (very carefully )the NWS forecast today, it’s a forecast for rain(as it should be).  However, why is the forecast so full of references to sleet and freezing rain and possibly snow flakes??? Beats me!  How long do you think it’ll take the weather service to get all the icy words out of the Louisville forecast?

Until they do, here’s my forecast.., Light rain should move into the area by 3-4 P.M.  Rain should get a little heavier during the evening hours, then should become more scattered again after midnight.  Temperatures will fall into the upper 30’s to near 40 once the rain begins.  Temperatures will hold fairly steady in the 36-38 range most of the night then fall to the mid 30’s tomorrow afternoon.

The above forecast is for the Louisville metro area.  As we get 20-30 miles north of Louisville a  little light freezing rain will be possible this evening, but it will quickly change over to all rain.  Roads are expected to remain wet, not icy.

Thursday Afternoon

Still pretty calm on the weather front.  We’ll see  a warming trend beginning tomorrow that will continue through Sunday.  Then we’ll begin a slow slide into colder weather beginning Monday.  Models remain very consistent.  Mostly sunny tomorrow, then cloudy Saturday with a small chance for rain near Louisville, but higher over Indiana.  Any rain that falls will be light.  For several days the models have been agreeing on a Sunday arrival of a strong storm from the southwest.  That will bring a chance for moderate to heavy rains and temperatures reaching as high as 60 or so.  The only difference since yesterday is a slight delay in the arrival of Sunday’s rain.  Favored time now seems to be Sunday afternoon and night.

Longer term:  Cold weather will be the rule for most of next week.  It’ll be generally dry after Monday, but we will see a chance for some light snow or flurries Wednesday night.

Winter Outlook

The National Weather Service today issued their winter outlook.  Meteorological winter is the months of December, January, and February.

This outlook has undergone some major changes (toward colder) in the past two months. The September edition had almost no area of the U.S. in “below normal” category.  Then, last month, they added Texas and a small area surrounding.  Today, that area has expanded to cover about three times more of the country.  That’s an amazing change, but I still don’t think they’ve gone nearly far enough to the cold side.  Now they have us with about a 35% chance for winter temperatures to be below normal.

I’ve checked a half dozen or so non-government sources for their winter forecasts and they generally run much colder than the “official” outlook.  I’ve mentioned before about a private group called Weather Bell Analytics.  For my money, I think they are the best around at seasonal forecasting.  Here’s their winter forecast.  I think it’ll be a lot closer to what actually happens than the NWS version.

Buffalo Snow

We’ve all been hearing about, and seeing pictures of the epic snows around Buffalo, New York.  Here are a few of the ones I like the best.

Just kidding

On the first two, you can see how narrow the bands of snow off the lake are.  Within 20 miles of the 5′-6′ snows you are likely to find areas with just a few inches of snow – it all depends on the wind direction!  The last photo gets my award for greatest ingenuity.

Saturday 5 P.M.

There’s an area of (mostly) light rain coming eastward from western Indiana.  It is weakening, and expected to continue that trend, but it should hold together long enough to bring some light rain to the Louisville area between roughly 7-9 P.M. this evening.

The rest of the weekend outlook looks pretty much on course (see yesterday’s post, below).  Slightly better chance –  about 30-40% – . for showers/t-storms tomorrow  until late afternoon.  The primary rain/storm chance remains tomorrow night and Monday.  There could be some pockets of heavy rain, but the GFS and NAM have reduced their rain total forecast from yesterday (especially the NAM) AND the HPC has dropped their forecast from 2″+ yesterday to 1 – 1.50″ today.