Secrets of Forecasting Snow

Snow, just the mention of it in the forecast induces panic and a rush on grocery stores to grab the last bread and milk lest we get stranded by what has affectionately become known as "White Death".

The map image is the model forecast snow accumulation by 10PM Tuesday. The yellow temperature shows that in Cincinnati at least the temperature will remain at or above freezing white the wet snow falls, as it tapers to flurries the temperature drops but at the same time the roads dry out. So an isolated icy spot is possible Wednesday morning.

The video below explains more about snow forecasting.

A Tale of Three Models - Part Deux

When working on the forecast yesterday for Christmas Day I was faced with three models and three different solutions.  To a meteorologist the forecast that results from a run of a weather model run is called a solution.

The American Model (called the GFS for Global Forecast System) said Christmas Day would be dry. The Canadian Model said it would rain then change to light snow for the morning of Dec. 26th. while the European Model had an all-day light snow falling.

Today the models are converging on a common solution close to the original GFS run and that means dry weather and no snow for Christmas.

The video below shows latest runs available.

5 Shopping Days Until Christmas.

So  just what will the weather look like for the remaining shopping days. Take a look at the video below.

Thinking About A White Christmas!

 A White Christmas is defined by the National Climatic Data Center for this map as a Christmas Day having 1" of snow or greater on the ground.

From the map above you see that the FOX19 viewing area is sandwiched between a 25% and a 10% chance of a white Christmas. The farther north you are in the Tristate - the better your chances are of having a White Christmas.

Official records have been kept @ CVG since 1947, before that at Abbe Observatory in Clifton then before that in Downtown Cincinnati starting November 1, 1870.

There are a variety of ways Christmas can be considered "White". The list below gives the chances of  based on official data and some additional Smithsonian Institution data going back to 1858.

WHITE CHRISTMAS STATS

SNOW FALLING  1858 – 2010 (152 YEARS) on Christmas Day

ANY SNOW FALLING ON XMAS DAY

15 TRACE DAYS + 19 MEASURABLE  DAYS  = 34 DAYS

34/152 =  22.4% CHANCE

MEASURABLE SNOW FALLING (>= 0.1” ON Christmas Day)

19/152 YEARS =  12.5% CHANCE

1” OR GREATER FALLING ON CHRISTMAS DAY

10/152 YEARS  =  6.6% CHANCE

2” OR GREATER FALLING ON CHRISTMAS DAY

7/152 YEARS  = 4.6% CHANCE

3” OR GREATER FALLING ON CHRISTMAS DAY

3/152 YEARS =  2% CHANCE

MOST SNOW FALLING ON CHRISTMAS DAY  7.0"  IN 1890

SNOW ON THE GROUND 1948 – 2010 (62 YEARS) On Christmas Day

ANY AMOUNT ON THE GROUND  (Trace + Measurable) 23/62 YEARS =                                                       37.1% CHANCE

TRACE ONLY (<1”)   12/62 YEARS          19.4% CHANCE

>= 1”  11/62 YEARS                                  17.7% CHANCE

>= 2”  7/62 YEARS                                    11.3% CHANCE

> =3” 6/62 YEARS                                        9.7% CHANCE

>= 4” 4/62 YEARS                                        6.5% CHANCE


MOST SNOW ON THE GROUND ON CHRISTMAS DAY  = 9" IN 2004

Go Cheviot! New State Rainfall Record

Cheviot is #1 - Breaking a 141 Year Old Rainfall Record.

Courtesy: Google Earth

Official rainfall records from the National Weather Service are augmented by the valuable observations of volunteer cooperative observers, COOP Observations, (pronounced Co-Op), for short.  They are trained and their instruments meet the standards set by the NWS so when a cooperative observer sets a record it can be believed.

So far the total rainfall measured by the Cheviot COOP for 2011 is 73.81"  that breaks the All-time Ohio State record for wettest year. The former record was set at Little Mountain, northeast of Cleveland with 70.82" way back in 1870. If Cheviot maintains its lead through the remainder of December the record will become official.

For reference the Kentucky state record for wettest year is 79.68" set in 1950 at Russellville, southwest of Bowling Green. The Indiana record is an amazing 97.38" set in 1890 at Marengo which is northwest of Louisville, KY.

Rain, Rain Go Away!

As we approach a yearly total of 70" of rain, after another record setting day (yesterday's total of 2.76" the wettest December 5th on record) my thoughts are drifting to places about as wet as Cincinnati has been. The Congo river basin, The Amazon River basin are two such places, admittedly much wetter in spots than Cincinnati has been.

Yesterday's 2.76" goes down as the 42nd "official" wettest day in Cincinnati, but how does that compare?  Here are the wettest 10 Days in Official Cincinnati weather history. Official records begin November 1, 1870.

3.9.1964      5.21"
3.5.1897      4.97"
3.13.1907    4.59"
10.20.1985  4.30"
3.25.1913    4.15"
7.27.1926    4.07"
1.21.1959    3.97"
7.15.1962    3.93"
7.20.1925    3.77"
9.26.2011    3.76"