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Quick update

Sun., Jan 7, 2018

The short term models have, as expected, all gone to a forecast for the Louisville area which consists of almost all rain tonight and tomorrow morning AND  a few periods of sleet/snow mixed in.  But, essentially we’re just looking a a rain situation locally as temperatures remain above freezing all night.

Doesn’t look like the NWS has given up on its icy prediction yet.

What’s going to happen tonight?

Sunday, January 7, 2018

Which precipitation type will dominate tonight?

Forecasts have been calling for snow and/or sleet and/or freezing rain and/or rain for tonight and Monday morning for several days now.  But, as we get closer to the event, the actual sequence of events seems to be coming into clearer focus.  The computer models are still quite varied – I’ve just looked at five different models and the results still are different.  One says mostly snow, another says mostly freezing rain/sleet, two say about a fifty-fifty split between icy types and rain, while another one predicts mostly plain old liquid rain.

So that aspect of the models doesn’t provide much help.  So maybe it’s time to put a little common sense human forecasting to work.  One thing the models do agree on is surface temperatures.  In general, they all hold surface temperatures above freezing overnight and tomorrow.  Thus, any icy precipitation that mixes in should melt on roadways.  Concrete sidewalks and roadways could get a bit icy late this evening.  Once precipitation begins this evening, temperatures will drop  few degrees for an hour or two.  During that time we’ll see our best chance for icy precipitation mixing in with rain.  After midnight, by far the dominant feature will be rain as temperatures rise into the mid to upper 30’s by morning.

So, summary, when all is over, this system should cause only a few, if any, problems for the Louisville area any all roads should be fine (although wet) for rush hour.  However, north and northeast of Louisville more ice will mix in, especially those areas which still have some snow on the ground.  Numerous road problems are likely in these areas.

Can Nate help us?

Friday, Oct. 6, 2017  11 A.M.

Recent changes cast doubt on current forecast.

This morning’s GFS model run has pushed Nate’s path farther east than the current forecast implies.  If this works out, and it likely will, our local hopes for some very beneficial rain this weekend are dimming.  Current official forecast calls for widespread 1″-2″ rainfall over our area late tomorrow into Sunday.  Forecast  changes this morning would indicate our rainfall will probably be less than half that of the current forecast.

As it looks now, we should get at least some rain this weekend, but not enough to take much of a bite out of our growing drought conditions.  A quarter to half an inch would be nice, but I’m getting the feeling I may be too optimistic.

Bummer.

Air Show/Thunder Friday update

5:45 P.M. Friday, April 21, 2017

Model solutions have done a flip-flop in the past 24 hours.  Yesterday, the NAM gave by far the best weather outlook for Saturday’s events.  Today the GFS is our friend.  Which one is right?  Good question!  I’ve asked myself the same question many, many times over the years.  Usually, there’s at least some “truth” in both models.  The NAM, as expected, had a better take on today’s weather.  Tomorrow, it appears to me that the GFS has a better handle on the situation.  Here’s how I see it evolving:

First of the heavier rain systems moves into the Louisville area between 7 and 8 P.M.  Rain could get heavy at times late tonight and tomorrow morning.   Rain ends during the midday hours (Noon – 2 P.M.).  Cloudy and cold rest of afternoon into the evening  (50-ish temperatures likely). So, air show should be dry but a low-hanging cloud cover may hinder some of the action.  For the fireworks, it’ll be breezy and cold  (near 50).  And, here’s where the NAM adds to the forecast – there’ll be about a 50-50 chance for light rain and/or drizzle during the show.

Drier news for air show/thunder

4:30  P.M. Thursday, April 20, 2017

Current situation:

Weak upper air system moving through the Great Lakes may create strong thunderstorms over NE Indiana and Michigan for the next few hours.  We, however, are too far south to join in on the stronger dynamics with this system.  Enough energy is left for us to (probably) see two episodes of showers and thunderstorms over the next 6-8 hours.  A loosely organized line of showers/thunderstorms will move across the Louisville metro area between now and 6 P.M.

A second, better organized, system should bring a more widespread area of rain/thunder between 8 P.M. and 11 P.M. tonight.

Note: Models can’t agree about tomorrow: NAM brings a large area of rain over us tomorrow afternoon.  GFS keeps us dry tomorrow with rain arriving tomorrow night.  Either way, it will be cooler.  (NAM looks better to me)

Air Show/Thunder:

Both models are developing the next weather system faster than they had earlier in the week.  If this trend continues, it signals a better outlook for Saturday.  Steady, heavier rains look to end by midday.  Cloudy skies remain during the air show, but at least it should be dry.  As cooler air arrives during the afternoon/evening we’ll see temperatures drop to the low to mid 50’s.  Add breezy winds and a winter coat will feel good for the fireworks.  In addition, Saturday evening could also be hit with a cold drizzle.  Still, better than earlier forecasts.

Strong storms possible until 7 P.M.

Monday, March 27, 2017  5:30 P.M.

We’re on the northern edge of a Severe Thunderstorm Watch currently.  Primary concern lies south of Louisville over central KY and, especially, central TN.  Activity is due to a small, but intense upper level disturbance racing over the lower Ohio Valley.  Once again, the upper dynamics are strong, but the lower level instability is quite weak.  For the past  few hours, clusters of thunderstorms have been moving NE from southern/southwestern KY.  A few severe storm warnings have been issued, but it appears most of the storms, while strong, have stayed below severe limits (58 mph winds).  Main factor for us has been the weakening of the storms as they encounter the more stable air mass near the Ohio River.

Main line of storms will push through the I-65 corridor (and Louisville area) between 6 and 7 P.M. this evening.  Strong wind gusts and, perhaps, isolated spots of small hail will be likely as the line passes by.  Overall, these storms should have little affect on our  metro area.

BY 7 P.M. any storm threat for the Louisville are will end.  Any additional threat for severe storms will continue east and southeast of us.

Stuff

A little late for the big day itself, but some things to remember about St. Patrick:

1).  He was not Irish.  (He was born in England, sold into slavery in Ireland as a child.  He later escaped and returned to England where he became a priest.  Then he returned to Ireland to help bring Christianity to Ireland.

2).  It is true that there were no snakes in Ireland when Patrick died.  However, there were no snakes in Ireland when he arrived as a priest.  Irish snakes were destroyed about 10,000 years BEFORE Patrick’s era by the most recent Ice Age.

 

 

Wow! It’s snowing!

Monday, March 13, 2017  3 P.M.

Just looked out the window and saw some (very light) snow.  Large area of precipitation on NWS radar moving slowly eastward should continue the snow for a couple of hours.  No accumulation on  roadways as temperatures are above freezing.  Radar showing a classic “bright band” over Meade and northern Hardin Cos.  That’s the area where the snow is melting aloft and thus creating a change from snow to rain.  That snow-to-rain transition will reach the Louisville area by around 5-6 P.M.

Enjoy the snow while it’s still here.

Nature’s still teasing us

Friday, March 10, 2017  11:30 A.M.

Oh, so close! But apparently not close enough as this morning’s GFS and NAM continue to keep any snow tomorrow afternoon just a bit to our west and south.  Plenty of moisture seems to be available, but both models place the primary area of atmospheric lift about 200 miles to our west tomorrow morning, then curving around to our south by evening.  We’ll be watching a very cloudy sky…most likely with nothing falling from those clouds.

But, we’ll see another chance for light snow/flurries late Monday into Tuesday.

Latest GFS snow forecast from last night’s run: