A LOT OF WINTER ON THE WAY

Good afternoon.  After a brief break, winter is back in full force.  Parts of northern Indiana could have significant totals on the ground before the week is over.  Before I get into everything, here are some quick headlines of what I am tracking this week:

-light snow north tonight

-snow system New Years Day through Thursday

-storm system for Sunday

-major arctic cold next week?

A weak clipper arrives tonight for northern Indiana.  This will stay north of Indianapolis.  Parts of extreme northern Indiana could pick up 1" out of this by tomorrow morning.  

Another system arrives beginning Tuesday night for extreme northern Indiana, and that snow will stall out for a while up that way, and gradually push across the state late New Years Day into Thursday.  Lots of question marks remain for this system.  The system will be diving out of the polar jet, however there will also be a storm system coming out of the subtropical jet to the south.  When these two streams phase, this could become a bigger storm.  However, at this time it appears these will phase to our east.  How quickly they will phase will impact snow totals locally.  At this time there is potential for accumulating snow, whether it is an inch or several inches remains to be seen.  If you are heading out east to the East coast NYC/Boston/etc. there could be significant amounts of snow late this week.  Let me quickly show you a couple model runs.  Here is the snowfall output from the latest GFS.  It puts significant snow down along the Indiana counties bordering Michigan, with 2-4" elsewhere across the state. 

To compare, here is the NAM snowfall output.  Notice how it is not impressed with the snow totals unless you are up in extreme northern Indiana.  **These are just model runs---not an actual forecast!!** 

There will be an arctic front approaching our region on Sunday, and the question remains whether or not a storm will develop along it.  Some models say oh yes, while others show only a little bit of precipitation as the front moves through.  Confidence remains very low as the models are on their usual waffles.  

Behind that front, there is potential for some very frigid temperatures next week.  Some of the models have been spitting out EXTREMELY cold numbers.  Have to urge extreme caution, models have been going back and forth on this.

Bottom line, there is lots to track over the next week.  Expect changes!  

REMEMBERING THE HISTORIC WINTER STORM OF DECEMBER 22-23 2004

9 years ago the state was in the midst of what would be the biggest snowstorm in history for some areas, as two major storms crossed over the Ohio Valley within a few hours of each other.  I will never forget this one, I was 10 years old and this was the storm that really sparked my interest in weather, especially winter storms.  I remember visiting family in French Lick for Christmas, and measuring 24" of snow on the ground.  Here is a full write up of this storm all from the NWS office in Louisville, KY:

22 December 2004
central Kentucky and southern Indiana
Historic Winter Storm

A historic and major winter storm affected much of the Ohio Valley from the 22nd into the 23rd of December 2004. Two bursts of heavy snow, separated by a few hours, brought over two feet of snow across several counties north of the Ohio River in southern Indiana. Interstates 64 and 65 across southern Indiana were closed for a number of hours during this storm. Snow totals of 30 inches or more were measured across portions of Washington, Jefferson, and Scott counties. Further south, an amazing 6 inches of sleet fell in one location across Henry County. Significant sleet accumulations also fell on the Louisville metro area. Thundersnow and thundersleet were observed during this event, with snowfall rates approaching 4 inches per hour in some southern Indiana locations. Across central Kentucky, freezing rain brought up to an inch and a half of ice across an area from Bowling Green through Nelson County. Ice accumulations caused considerable tree and some structural roof damage in Hardin and Nelson counties.

You can view a 3 hour duration radar loop during the evening of 22 December...pretty much the peak of the event. Click here to view...however note that the file is 3 MB large any may take a few moments to download over slower Internet connections. You can see the persistent banding which lead to large snow and sleet totals. A couple strikes of cloud to ground lightning were also seen, indicating the thundersleet or thundersnow.

 A large scale 500 MB trough over much of North America provided an environment favorable to ascent over the Ohio River Valley. This analysis was valid at 00 UTC on 23 December 2004 (7 PM EST 22 December).

 A relatively weak surface low was located over the Gulf Coast states, allowing moist air to flow northward into the Ohio Valley. This clearly shows you that it does not take a deep cyclone to create significant winter storms in this part of the country. This analysis was also valid at 00 UTC on 23 December 2004 (7 PM EST 22 December).

 This map shows an approximate analysis of snow and/or ice accumulations, in inches, across the NWS Louisville area of responsibility.

 A surface temperature analysis early Christmas morning (a couple days after the winter storm). The deepest snowpack is well correlated with the coldest temperatures that morning. It took nearly a week after the snowstorm for the deepest snows to melt completely.

Here is a county-by-county listing of snow, sleet, and ice totals from the event:

THE FOLLOWING ARE COUNTY-BY-COUNTY *MAXIMUM* PRECIPITATION TOTALS 
GATHERED FROM LAW ENFORCEMENT AGENCIES, STORM SPOTTERS, 
COOPERATIVE OBSERVERS, AND OFFICIAL REPORTING STATIONS.

.SOUTHERN INDIANA...

COUNTY               SNOWFALL               COMMENTS
------------------------------------------------------------------
DUBOIS               20 INCHES              4 FOOT DRIFTS
PERRY                20 INCHES
ORANGE               30 INCHES         EST BY TRAINED SPOTTER
CRAWFORD             23 INCHES              5 FOOT DRIFTS
HARRISON             20 INCHES
WASHINGTON           32 INCHES              5 FOOT DRIFTS
FLOYD                14 INCHES
CLARK                15 INCHES
SCOTT                29 INCHES
JEFFERSON            17 INCHES              EASTERN PART OF THE COUNTY
JEFFERSON            30 INCHES              FAR WESTERN PART OF COUNTY

.NORTH CENTRAL KENTUCKY...

COUNTY               ACCUMULATIONS          COMMENTS 
-----------------------------------------------------------------
HANCOCK              17-19 INCHES           5 FOOT DRIFTS
BRECKINRIDGE         15+ INCHES
MEADE                10+ INCHES
BULLITT              4-6 INCHES
SPENCER              4-5 INCHES
JEFFERSON            9 INCHES           OFFICIAL FROM SDF (LOU ITNL)
OLDHAM               9 INCHES
HARDIN               3-4 INCHES SLEET WITH 1 INCH OF ICE
NELSON               1 INCH OF ICE WITH 2 INCHES OF SNOW/SLEET ON TOP
WASHINGTON           1/4 TO 1/2 INCH ICE WITH A LITTLE SNOW
TRIMBLE              12 INCHES              2 FOOT DRIFTS
SHELBY               5.5 INCHES             INCLUDES 3.5 INCHES SLEET
HENRY                9 INCHES               INCLUDES 6 INCHES SLEET

.SOUTH CENTRAL KENTUCKY...

COUNTY               ACCUMULATIONS          COMMENTS 
------------------------------------------------------------------
OHIO                 8 INCHES               MORE IN THE NORTHERN PART
                                            OF THE COUNTY
BUTLER               3-4 INCHES OF A SLEET/SNOW MIXTURE 
GRAYSON              6 INCHES OF SLEET AND SNOW
CUMBERLAND           2/10 INCH OF ICE

.EAST CENTRAL KENTUCKY...

COUNTY               ACCUMULATIONS          COMMENTS 
------------------------------------------------------------------
FRANKLIN             1/4 TO 1/2 INCH ICE, 1 INCH SLEET AND SNOW 
WOODFORD             1/4 INCH ICE
SCOTT                1/2+ INCH ICE, WITH SOME SLEET AND SNOW
FAYETTE              1/4 INCH ICE
JESSAMINE            1/4 INCH ICE
GARRARD              1/4 INCH ICE
MADISON              1/4 INCH ICE NEAR WESTERN BORDER, LOWER AMOUNTS
                     ELSEWHERE
CLARK                LIGHT GLAZE OF ICE
BOURBON              1/4 INCH ICE
HARRISON             1/2+ INCH ICE
NICHOLAS             LIGHT GLAZE OF ICE
MERCER               1/2+ INCH ICE

Here is a listing of the low temperatures observed the morning of December 25th:

...ACROSS SOUTH CENTRAL INDIANA...

   LEAVENWORTH     MINUS  7
   SCOTTSBURG      MINUS 19
   TELL CITY       PLUS   5
   HUNTINGBURG     MINUS 13
   PATOKA LAKE     MINUS  7

...ACROSS NORTH CENTRAL...SOUTH CENTRAL AND EAST CENTRAL KENTUCKY...

   LOUISVILLE NATIONAL WEATHER SERVICE OFFICE          0
   LOUISVILLE INTERNATIONAL AIRPORT              PLUS  2
   LOUISVILLE BOWMAN FIELD                       PLUS  2
   FRANKFORT                                     PLUS  3
   BOWLING GREEN                                 PLUS  9
   COVINGTON                                    MINUS  2
   WOODBURY                                      PLUS  4
   ROCHESTER FERRY                              MINUS  3
   HERRINGTON LAKE                               PLUS 11
   MARROWBONE                                    PLUS  9
   BARREN RIVER LAKE                             PLUS 10
   GREEN RIVER LAKE                              PLUS 14
   NOLIN RIVER LAKE                              PLUS  4
   ROUGH RIVER LAKE                             MINUS  4
   FORT KNOX                                    MINUS  2             
   LEXINGTON                                     PLUS  8

Quick December Recap - Latest on Super Soaker Weekend Ahead - MAJOR FLOODING POSSIBLE!

Good evening.  Hard to believe there has been snow on the ground since December 5th!!  It has been a remarkable start to meteorological winter, with the entire state at a much faster than normal pace of snowfall.  Here in Martinsville, my snowfall total for the season so far stands at 9.4".  Already well on our way to the average 25.9" for the season.  Another side of the story has been the COLD.  Some areas went nearly two weeks without going above freezing.  That of course is why the snow has been sticking around.  The deep snow pack helps reserve the cold air.  When you have a decent snow pack develop, it acts like a freezer, helping keep temperatures colder.  

Check out the current snow cover across the U.S. (courtesy of WSI).  A decent snow pack is still present across most of Indiana, but there is going to be a huge dent in that as we head towards the weekend, as some MAJOR changes are about to occur.  

When you step outside tomorrow morning, you will notice milder temperatures.  With a steady south flow all night, even with clear skies, temperatures will remain a touch above freezing for most of the night.  A good 15-20 degrees WARMER than this morning.  Temperatures tomorrow will continue to warm up.  There will likely be a big temperature spread from north to south.  Areas with the most snow cover in northern Indiana may struggle to get out of the 30's, while southern Indiana gets well into the 50's.  Most of central Indiana should get well into the 40's.  Remember the deeper the snow depth in your area, the tougher it will be for temperatures to really respond.  This could also lead to a fog issue in northern areas tomorrow, with that warmer air flowing over the cold, snow covered ground.  The good news is that most areas should remain rain-free.

The rain chances begin by Thursday night, and this will be the beginning of a VERY WET period of weather.  Rain will be likely throughout the day on Friday, although it should not be all that heavy.  There will once again be a huge temperature spread, from low 40's north to middle 50's south.  

It is going to be an extremely wet weekend, with major, major flooding possible.  By time we get into Saturday, a huge storm system will be gathering strength and approaching the area.  Expect rain and rainfall rates to really go up by Saturday afternoon, with the heaviest rain setting up Saturday evening through noon Sunday.  Rainfall rates could be extremely heavy.  Check out the map for 7am Sunday.  The flood gates of the Gulf of Mexico are wide open, pumping in an enormous amount of moisture aimed right here into the Great Lakes and Ohio Valley.

Between Friday and Sunday, a good portion of the state will be seeing anywhere from 3-5" of rain laid down, with local amounts of 6" or more likely.   This is EXTREMELY concerning!!  Parts of the state still have 6-8" of snow on the ground,  as we melt that, and add an enormous amount of water on the already water-logged ground, this is going to create major problems.  I think this could be historic flooding.  If you lived in a flood-proned area, now is the time to prepare.  Even areas that don't normally flood could be affected.  Here is the 7-day rainfall potential map from WPC.  That is A LOT of rain!

Based on the latest track of the storm, it now appears this will only be a rain event for all of Indiana.  There could be some backlash wintry stuff late Sunday in northern Indiana, but even that would not be much.  I can't believe it after nearly 2 weeks of snow on the ground, but the chances of a white Christmas look very low.  The good news is that the pattern quiets down for a good part of next week, so other than a few flurries, Christmas Eve and day look pretty nice, with seasonably chilly temperatures.  

I will continue to update on the flooding potential.  Thanks for reading!  

WINTER STORM ON THE WAY - LATEST FORECAST

Good morning.  Our first winter storm of the season is on the way.  The system appears to be coming in 2 waves.  One tonight, and another one tomorrow.  The one tomorrow will be the stronger one that will bring the brunt of the snow accumulations.  

Precipitation looks to break out and become widespread after 4pm today.  It will likely fall as a wintry mix in central Indiana, with rain south.  As the evening progresses, the rain/snow line will be shifting south.  Important to note travel this evening (by 6pm and after) could be a big mess with the sleet/freezing rain mixed with the snow.  The best chances for freezing rain will be across the southern part of Indiana tonight.  By midnight, most of central Indiana should be plain snow, possibly with some sleet still mixed in.  Southern Indiana will hold on to a wintry mix longer through the night, but should go to all snow as the overnight progresses.  Watch out for a glazing of ice with snow on top of it to make travel and getting around slick and hazardous.  About 2" of snow/sleet accumulation is possible across central and south/central Indiana by tomorrow morning.

Round 2 arrives during the day tomorrow.  After a brief lull early tomorrow morning, snow will return for a good part of central and southern Indiana.  There is a likelihood that snow will be quite heavy at times south of I-70.  Several inches will accumulate throughout the day.  Roads will be snow covered and hazardous.  

The snow finally winds down by 7/8pm, but not before dumping heavy snow over southern Indiana.  Here is a look at my updated snowfall potential map.  I want to point out that the snowfall forecast in central Indiana is quite difficult, because a big question mark remains for how far north the precipitation shield can get tomorrow.  There will likely be a sharp cut-off.  My latest forecast is not much different from the one I posted last night, but I did add a 3-6" band over Indianapolis and points directly south/east.  There may be a pretty good cut-off northwest of the city.  

My Facebook page is the place to be for plenty of updates on this storm! If you haven't given it a "LIKE" yet - be sure to do so! - https://www.facebook.com/Nathanwx

Tornado Outbreak Update - Latest Forecast Through Thanksgiving Week

It has been nice to have some calm weather over the past couple of days after the historic outbreak of tornadoes we just experienced on Sunday.  My prayers go out to everyone who has been displaced from their homes.  I could not even imagine.  Here is the latest on where the outbreak stands...

To put it briefly, temperatures will warm up back in the lower 50's tomorrow through Friday.  Enjoy some sunshine and dry weather tomorrow.  Rain chances return Thursday and Friday.  Right now, the wettest day appears to be Friday.  


The weekend will feature a HUGE dip in the jet stream.  Bottom line, it will get VERY cold!!  Any lingering precipitation Saturday morning could be in the form of snow flurries, but by Saturday afternoon and Sunday, dry weather will be the rule.  Obviously a much different weekend than the last one!  Temperatures Saturday will fall in the 30s through the day with teens Sunday morning.  Highs on Sunday will not get out of the 20s.  This is about 25 degrees off from normal.  Check out the arctic air mass spilling right into the Ohio Valley this weekend...

Temperatures will remain chilly for Thanksgiving week, with highs several days next week only in the 30s if current models are correct.  A couple of snow chances appear on the table, but these do NOT look like anything to get excited about at this point.  The forecast confidence for next week is low and subject to change.  

Thanks for reading!  As always, you can find more weather updates on my Facebook and Twitter pages.  

Severe Storms On Sunday

For this post, I am only going to be focusing on the severe weather potential on Sunday, since today and tomorrow will be fairly quiet with warming temps.

I have watched the models converge on an increasing idea of severe weather on Sunday.  A few of the things meteorologists look at to predict severe weather events are things such as wind shear and instability.  Let's dive in. 

WIND SHEAR

This looks impressive on Sunday.  This indicates that Sunday will be a windy day - storms or not, but this high wind shear aloft also means that storms could easily tap into it, and produce damaging winds here at the surface.  This can also aid in the development in tornadoes if these winds are turning enough in direction with height - also known as directional shear for the weather nerds out there.  The map below shows the 500 mb winds for 8pm Sunday evening.  That purple indicates winds over 100 knots blowing above our heads on Sunday!

The European shows a very similar set-up, although it does not indicate wind shear as extreme as the GFS.  

INSTABILITY

This appears to be slightly higher than the Halloween storm only because of timing.  GFS on the left and NAM on the right. Both images are 4pm Sunday.

MOISTURE

This looks impressive for mid-November with 60 degree dewpoints in many areas.  I am just showing the GFS model here.

TORNADO INDEX

One cool thing about the NAM model is that it can give tornado probs unlike other models.  It shows the best tornado potential to our west, but certainly showing a threat here too.

TIMING

It looks like most of the severe weather will be pushing through the region between 4pm and 10pm.  Before the main line pushes through, there may be some super cell storms that could become severe.  Something to watch.  

SPC SEVERE WEATHER OUTLOOK

The SPC has placed much of Indiana in a 30% risk for severe storms.  For SPC, that is a pretty high risk for 3 days out.

MY THOUGHTS:

I have no doubt that there will be some severe weather on Sunday, based on all the parameters we just discussed.  One thing that could hamper the risk slightly is if rain and clouds hold on Sunday - which I think has a decent chance of happening.  This would help keep instability levels in check.  However EVEN if we get no sun or dry time Sunday, the wind shear is high enough to compensate for that, and we would still have a risk for severe weather.  The highest threat Sunday evening is damaging winds without a doubt, with strong winds like that aloft.  I think we have a moderate risk for a few tornadoes.  Lower risks would include hail and flooding.  The Weather Channel gives tornado TOR-CON'S for regions when there is a potential for severe storms.  They are giving Indiana a 4 which means there is a 40% chance of a tornado within a 50 mile radius.  I want to stress I do not think this is a major outbreak like a March 2nd, 2012 event.  However, everyone in Indiana stands a chance for severe weather.  

I will have updates throughout the weekend on my Facebook page.  If you have not "LIKED" it yet on Facebook, you should go ahead and do that.  That way you will get my updates on what to expect.  

Have a great day, and stay safe.