Author Archives: wx

Hurricane Irma

Irma’s a Category 5

 

Irma is a long way from the U.S., but some islands like the U.S. and British Virgin Islands will get hit hard soon.  After that the various models seem to fall into two central ideas – both bring Irma WNW staying just north of Puerto Rico and Cuba (while wiping out the Turks and Caicos) until things change while she’s just south of Florida.  About half the models bring the storm north either over Florida or just off the east coast.  Then a move inland anywhere between Georgia and Myrtle Beach. (Hilton Head ?)
   Second set of models brings Irma along the west coast of Florida with landfall over the panhandle to as far west as Mobile.
   It’s anybody’s guess at this time – a few minor changes over the next few days could alter the forecast significantly.
As to intensity, Irma’s a Category 5 now.  The strongest hurricane ever observed purely over the Atlantic Ocean.  Stronger hurricanes have formed over the Atlantic Basin, but they were in either the Gulf of Mexico or the Caribbean Sea.
     While hurricane position forecasting has steadily improved, the same cannot be said for intensity forecasts.  They are notoriously poor!  Just yesterday the forecast for Irma was to remain a Cat 3 through tomorrow, then slowly weaken; today she’s a Cat 5. Today’s prediction is for Irma to slowly weaken over the next five days, but remain a major hurricane.
P.S. Just a final thought…The morning run of the U.S. workhorse forecast model, the GFS, brings Irma northward along the Florida Coast this weekend with landfall near the Georgia/South Carolina border.  The GFS then weakens the storm as it drifts northwest.  Finally, the GFS has Irma’s remnants fading away over Kentucky next Wed/Thu.  Just something to think about.
(I think you should NEVER believe  a weather forecast that far in advance – let’s see what happens.)

 

Hits and Misses

Thursday, August 3, 2017

Quote of the day.

Yesterday, as part of my waking-up ritual, I turned on NOAA Weather Radio to get my daily morning update.  Within seconds, I burst out laughing.  I thought I must have mis-understood what I heard.  But, a second time around I heard the same thing.  from the Hazardous Weather Outlook came this statement:  Some Thunderstorms may produce lightning.

Your tax dollars at work.

And, speaking of our tax dollars…is it just me, or do others believe that our “official” forecasts have been pretty bad this summer?  I know as well as anyone about the frustrations of forecasting convective systems.  But, we’ve been bombarded with forecasts of “rainageddon”, severe storms and chaos several times with nothing to show for it.  In fact, the biggest rain we’ve had recently (July 23) was barely given any attention.  That situation was fun to watch while it unfolded – the NWS changed/updated their forecast 4-5 times over about 8 hours AND the only one that was correct came out about 3 hours after the rain ended!    NOTE:  The NWS had another case of “the cat chasing its tail” a few days back when they issued a spurious heavy thunderstorm forecast about three hours after the threat had ended.

El Nino/La Nina outlook

Most of the first half of the year, NOAA’s long term climate forecast model, Cfsv2, was predicting a climb  back into mild El Nino conditions for late fall and winter.  Over the past couple of months, the model has done a flip.  Now, it’s forecasting a mild La Nina to develop.

The consequences/forecast for North America has also flipped -early forecasts indicated a below normal temperature for our winter.  Now, they are strongly indicating a very mild winter.

And, by the way… the current NWS forecast for tomorrow is just plain not going to happen.  No way.  We have about a 30% chance for showers around 8-10 A.M.  Nothing close to the “numerous showers and thunderstorms” in the forecast.

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.

Storm chances high late this afternoon

10:30 A.M. Wed., April 5, 2017

Atmosphere appears set up to do some damage later today – especially east of the I-65 corridor.  Strong upper air system is approaching and ample moisture is streaming northward.  That sets up a pretty high chance for thunderstorms as well as severe storms.  System will be slow to develop and will just be getting rolling about the time it hits central KY.  Strong/severe line of storms should pass Louisville area between 5 P.M. and 8 P.M.  Hail and high winds appear likely.   Storm line will intensify as it moves east of I-65 and heads toward I-75.  Also, higher risk for storms, some severe, over southern KY from I-65 eastward.

Much colder air arrives tomorrow.

Confusing weather…update #2

Thursday,March 30, 2017   5:15 P.M.

Severe storm threat has dropped to minimal, or less.

Situation is no longer “confusing” as the short term models continue to highlight the ideas presented earlier.  Some adjustments are needed to the timing, but the severe weather threat has moved to central Indiana eastward to central Ohio.  Severe storms are not expected locally.

Latest timing for Louisville metro area:

5 P.M. to 8 P.M.:  quite windy and warm, but only about a 5% -10% chance for a thunderstorm.

8 P.M. to 10 P.M.:  area of showers/thunderstorms (mostly moderate to strong)  moves from west to east across metro area.  No severe weather expected.

10 P.M. to 2 A.M.:  Rain with embedded weak to moderate thunderstorms continues.  Heavy rain briefly in thunderstorms.  Flash flooding is possible in a few areas.

2 A.M. to 4 A.M.:  Rain/thunder gradually fades away.

Confusing weather…3 P.M. update

Thursday, March 30, 2017  3 P.M.

Latest update based on short-term model and radar data…

1).  Most of the area (maybe all) should remain dry through at least 5 P.M.  Best chance for strong pop-up thunderstorms remains over Indiana.

2).  Between 5- 7 P.M.  Louisville area will see about a 40% chance for scattered thunderstorms.     Any storms that form could be strong, but any severe storms should be rare.  By 7 P.M. any chance for severe thunderstorms for the Louisville area will be over.

3).  By 7-9 P.M. a large area of strong-to-severe thunderstorms will break out over northern TN and southern KY and move rapidly northeast between I-65 and I-75.  Threat of severe storms will lie south and east of a line from Bowling Green to Cincinnati.

4). By 7 P.M. a weak cold front will be crossing the Wabash River (Indiana/Illinois border) and continue moving eastward.  At this time the front could be producing moderate to strong thunderstorms.  As the front moves eastward, its moisture will merge with the system mentioned in #3 (above) to create a large area of rain with weak to moderate thunderstorms mixed in.  This area should drop plenty of rain over our area between 8 P.M. and Midnight.  Some minor flash flooding will be possible.

A very confusing situation…

Thursday, March 30, 2017

The atmosphere may, or may not, be primed for severe storms later this afternoon/evening.  The confusion was apparent yesterday as the GFS and NAM far apart in their solutions for today’s weather/thunderstorm possibilities – the GFS wasn’t too keen on severe thunderstorms while the NAM jumped on severe weather big time.  Today, the GFS and NAM are closer, but still at odds.  Meanwhile the short term models, while agreeing in general about how things will evolve, are also divergent about the expected strength of any thunderstorms.

Going with the suspicion that each model has something good to add to the discussion, here’s how I believe the weather will evolve this afternoon/evening:                                                                First, the amount of cloud cover that remains this afternoon is very important.  Remains from storms to our west overnight have been hanging around this morning.  We should get enough brakes in the clouds this afternoon to allow some sunshine to build up heat (and energy) for some storms.  More sunshine is likely over KY than IN.  Lack of sunshine will diminish the severe storm threat.  Satellite data shows the clouds thinning as of Noon.

Second,  we have strong upper air dynamics over the midwest working their way slowly eastward, but surface conditions are a mishmash ( a highly technical term) of ill-defined air masses, outflow boundaries, and, so-far, ill-fated attempts to form a surface low pressure center and a cold front.  It looks as though it’ll take 4-8 hours or longer for things to get more organized.  By that time, the main threat for severe weather will shift east of the I-65 corridor.

Third, with lack of coordination between the upper and lower levels, things are just going to happen in a seeming random fashion this afternoon.  Quick-moving thunderstorms should pop up in a “hit ‘n’ miss” fashion over western and central KY and (mostly)  IN.  Most of these will be strong with gusty winds and hail possible.  Some could even reach “severe” limits, though these are likely to be few and far between.  By 6-7 P.M. the majority of these pop-up storms should be east of the I-65 corridor.  By this time, any severe weather threat should be over for the Louisville area.  Primary threat for severe storms this afternoon will be over central and northern Indiana.

Four,  by 7-8 P.M. the surface part of this system will be better organized and is expected to create a large area of rain and thunderstorms (non-severe)  over western KY and IN.  This will bring us a very wet evening.  Even a little flash flooding is possible.  Rain should diminish shortly after Midnight.

Comment

I see from this morning’s CJ  that  Rick and Cal are the two highest paid college basketball coaches in the land.  But, the educational ratings of the schools they coach are low.  We should gain an important bit of knowledge from the first two sentences.

Quick update – storms weakened quickly

Monday, March 27, 2017  5:50 P.M.

Storms are fading fast as they advance quickly northeast.  Louisville metro will see weak thunderstorms between 6 and 7 P.M.  There is no threat for severe weather – just some brief gusty winds and heavy downpours.

I suspect the NWS will drop the Watch for our area soon.  However, even if they let the WATCH linger, the threat for severe storms is already over.

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.