View Full Version : Oklahoma Weather Discussion - January 2013



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venture
01-01-2013, 12:57 AM
Another year of weather posts coming up. 2012 was definitely an interesting year weather wise, and the review is just below. I'm going to just tag this for the month of January for right now, even though we tend to bundle it with February. However, we'll see how things play out as it only takes one potential event to add about 12 pages to this thread. LOL

NWS Norman Weather Summary - 2012 Significant Weather Events Summary (http://www.srh.noaa.gov/oun/?n=events-2012summary)



There were 28 daily/monthly temperature records at Oklahoma City, and 26 at Wichita Falls (through Dec. 28th).
There were 4 daily/monthly precipitation records at Oklahoma City, and 4 at Wichita Falls (through Dec. 28th).
Oklahoma City tied its all-time record high of 113F on August 3. The daily high on August 3 at Will Rogers Airport had been preceeded by daily highs of 112F on August 1 & 2, making it the first time that max daily temperatures of 112F or greater had been recorded for OKC for 3 consecutive days.
Oklahoma City set a new all-time record warm low of 84F on August 3.
Temperatures at Oklahoma City (through November) were above average every month of the year except for October.
The preliminary 2012 tornado count for Oklahoma was 62. For western north Texas, a rain-wrapped tornado near Truscott on May 30 was the only recorded for the year.
The most active tornado month for Oklahoma was April, with a preliminary count of 52 tornadoes. This set a new record for the most April tornadoes in the state for any particular from 1950 through the present year.
No Oklahoma tornadoes were recorded in June. May, historically the most active month, saw only 4 tornado reports, which tied it for third for the least total of tornadoes for the month of May since offical records began in 1950.
The highest-rated tornado in our area was an EF-3 that struck Woodward on the late evening of April 14 and early morning of April 15. The Woodward tornado killed 6 people and injured another 29 people, and was the only killer tornado in Oklahoma in 2012.
The period from May through November of 2012 was the driest May-Nov. for the state of Oklahoma according to the Oklahoma Mesonet.


http://www.srh.noaa.gov/images/oun/wxevents/2012sigwx/2012sigwx.jpg



This initial post will contain information, images, and links that can be used at any time. Images posted later through the thread may or may not be accurate on the day you are viewing them (check the post comments). Information contained in this thread should not be used as an alternative to weather radios, media, or other means of getting weather warnings/advisories.

Current Conditions


Norman Warning Area MapTulsa County Warning Area Maphttp://forecast.weather.gov/wwamap/png/oun.png (http://www.srh.noaa.gov/oun/)http://forecast.weather.gov/wwamap/png/tsa.png (http://www.srh.noaa.gov/tsa/)Tornado Warning | Tornado Watch | Severe Thunderstorm Warning | Severe Thunderstorm Watch
Red Flag Warning | Fire Warning | Severe Weather Statement | Special Weather Statement
Hazardous Weather Outlook | Fire Weather Watch
Other Color Meanings: Web-Based Watch/Warning/Advisory Map Colors - NOAA's National Weather Service (http://www.weather.gov/wwamap-prd/faq.php)Oklahoma Mesonet Current Conditions
Red - Air Temp, Green - Dewpoint, Barbs - Wind Speed/Direction, Gray - Gusts, Blue - Precip since Midnighthttp://www.mesonet.org/data/public/mesonet/maps/realtime/current.wx.gif (http://www.mesonet.org/index.php/weather/map/current_conditions/current_conditions)
Severe Weather Information

Current Watches (http://www.spc.noaa.gov/products/watch/)Current Mesoscale Discussions (MCD) (http://www.spc.noaa.gov/products/md/)http://www.spc.noaa.gov/products/watch/validww.png (http://www.spc.noaa.gov/products/watch/)http://www.spc.noaa.gov/products/md/validmd.png (http://www.spc.noaa.gov/products/md/)
Snowfall Images
24 Hour Snowfall Totalshttp://www.nohrsc.noaa.gov/interactive/html/map_only.php?var=snowfall_24_h&min_x=-103.5&min_y=33.0&max_x=-94.0&max_y=38.0&bgvar=dem&shdvar=shading&title=2&width=600&height=450&font=0&lbl=m&palette=0&h_o=0&metric=0&snap=1&o6=1&o9=1&o13=1
6 Hour Snowfall Forecasts (http://www.weatherstreet.com/states/oklahoma-snowfall-forecast.htm)
6 Hr12 Hr18 Hr24 Hr30 Hr36 Hr42 Hr48 Hrhttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt1_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt2_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt3_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt4_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt5_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt6_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt7_oklahoma.pnghttp://www.weather.gov/forecasts/graphical/images/oklahoma/SnowAmt8_oklahoma.pngFire Weather Images


Oklahoma Mesonet 24-inch Fractional Weather Index Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png)
Image will appear blank overnight.http://www.mesonet.org/data/public/mesonet/maps/daily/mesonet.daily.current.FW60.grad.png?1343628443278O klahoma Mesonet Relative Humidity Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.ir.png)
Enhanced Colors - Blues are higher/colder cloud tops, Reds are warmer normally clear skies.http://www.mesonet.org/data/public/mesonet/maps/realtime/current.RELH.grad.png

Oklahoma Mesonet -Burn Index Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png)
Image will appear blank overnight.http://okfire.mesonet.org//data/public/mesonet/models/realtime/nfd/images/latest.bi.gif?1343629065Oklahoma Mesonet Consecutive Days with Less Than 0.25" of Rain Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.ir.png)
Enhanced Colors - Blues are higher/colder cloud tops, Reds are warmer normally clear skies.http://www.mesonet.org/data/public/mesonet/maps/daily/mesonet.rainfall.quarterinch.png

SPC Fire Weather Outlooks
*Click any above graphic to view discussion.*
Day 1 (http://www.spc.noaa.gov/products/fire_wx/fwdy1.html)Day 2 (http://www.spc.noaa.gov/products/fire_wx/fwdy2.html)Days 3 to 8 (http://www.spc.noaa.gov/products/exper/fire_wx/)http://www.spc.noaa.gov/products/fire_wx/day1otlk_fire.gif (http://www.spc.noaa.gov/products/fire_wx/fwdy1.html)http://www.spc.noaa.gov/products/fire_wx/day2otlk_fire.gif (http://www.spc.noaa.gov/products/fire_wx/fwdy2.html)http://www.spc.noaa.gov/products/exper/fire_wx/imgs/day38otlk_fire.gif (http://www.spc.noaa.gov/products/exper/fire_wx/)



References



COD Weather Analysis Page: COD Meteorology -- Surface and Upper Air Data (http://weather.cod.edu/analysis/)
NWS Norman Page: NWS (http://www.srh.noaa.gov/oun/)
Storm Prediction Center: Storm Prediction Center (http://www.spc.noaa.gov/)
Oklahoma Mesonet: Mesonet | Home Page (http://www.mesonet.org/)
West Texas Mesonet: Texas Tech University : West Texas Mesonet (http://www.mesonet.ttu.edu/)
Oklahoma Fire Weather: NWS Norman Fire Weather Forecasts (http://www.srh.noaa.gov/oun/?n=fireweather)
Oklahoma Road Conditions: Road Conditions (http://www.dps.state.ok.us/cgi-bin/weathermap.cgi)
Severe Weather Values Reference Guide: The Southern Indiana Weather Spotter's Reference (http://weatherspotter.net/index11.php) -or- SEVERE WEATHER INDICES PAGE (http://www.theweatherprediction.com/severe/indices/)
TwisterData Model Page: TwisterData.com | Weather Data & Model Forecasts (http://www.twisterdata.com/)
Earl Barker's Central US Model Page: Earl Barker's CENTRAL US Model Page (http://128.121.193.153/central_models.htm)
NSSL WRF Model: NSSL Realtime WRF model Forecasts (http://www.nssl.noaa.gov/wrf/)
NSSL 4KM WRF Model Forecast Soundings: NSSL 4km WRF Forecast Soundings (http://www.nssl.noaa.gov/wrf/sdg/)
HRRR Rapid Refresh Model: HRRR Model Fields - Experimental (http://rapidrefresh.noaa.gov/hrrrconus/)


Tutorial: HOW TO VIEW DATA IN HRRR

Step 1) Go the main page: High-Resolution Rapid Refresh (HRRR) (http://ruc.noaa.gov/hrrr/)
Step 2) Click on 3km HRRR-CONUS hourly (http://rapidrefresh.noaa.gov/hrrrconus/)
Step 3) Under Domain select SC for South Central US
Step 4) Look at the time frames available. Usually if it isn't through Hour 06 yet, I'll just go up to Date and select the previous time.
Step 5) Depending on what you want to see you can click on the specific time or to loop all the times available you'll see a Check Mark under loop. You can click that to loop them all.




State Radar ImagesWSR-88D Twin Lakes (http://radar.weather.gov/radar.php?product=N0R&rid=TLX&loop=yes)Base Reflectivity 0.5 deg tilt (http://radar.weather.gov/radar.php?product=N0R&rid=TLX&loop=yes)
http://radar.weather.gov/lite/NCR/TLX_loop.gif (http://radar.weather.gov/radar.php?product=N0R&rid=TLX&loop=yes)
WSR-88D Frederick (http://radar.weather.gov/radar.php?product=N0R&rid=fdr&loop=yes)Base Reflectivity 0.5 deg tilt (http://radar.weather.gov/radar.php?product=N0R&rid=fdr&loop=yes)
http://radar.weather.gov/lite/NCR/FDR_loop.gif (http://radar.weather.gov/radar.php?product=N0R&rid=fdr&loop=yes)
WSR-88D Vance AFB (http://radar.weather.gov/radar.php?rid=vnx&product=N0R&overlay=11101111&loop=no)Base Reflectivity 0.5 deg tilt (http://radar.weather.gov/radar.php?rid=VNX&product=N0R&overlay=11101111&loop=yes)
http://radar.weather.gov/lite/NCR/VNX_loop.gif (http://radar.weather.gov/radar.php?rid=VNX&product=N0R&overlay=11101111&loop=yes)


​State Satellite Images

Oklahoma Mesonet Visible Satellite Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png)
Image will appear blank overnight.http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png)Oklahoma Mesonet IR Satellite Image (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.ir.png)
Enhanced Colors - Blues are higher/colder cloud tops, Reds are warmer normally clear skies.http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.ir.png (http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.ir.png)

ksearls
01-01-2013, 01:50 AM
This is awesome. Thank you for feeding my weather freakiness.

venture
01-03-2013, 12:43 PM
So the weather doesn't look to eventful coming up, but this is what we have.

Tomorrow/Saturday - Weak system moving through Texas bringing light snow/rain over south of the Red. Maybe some light rain/snow mix over NE OK Sat morning.

Next bigger storm system is on Tuesday. This originally showed some good heavy rain for OK, but yeah that's gone. Look for light to moderate snow accumulations over far NW OK and some decent rain over far southern and SE OK. Maybe a sprinkle here. Snow accumulations to the NW look like 3-5" right now in some spots.

And that's pretty much it for precip chances, as of right now, through the 19th. Exciting stuff I know!

No real warm days coming either, things are just going to stay about like this (maybe a bit warmer into the mid/upper 40s). Could be worse I guess.

venture
01-03-2013, 09:41 PM
For those looking for any of the upcoming Spotter Training classes, NWS Norman has put the schedule out: NWS Norman Spotter Schedule (http://www.srh.noaa.gov/oun/?n=spottertalk)

These are just for the live, in person training events. Most of the training though is now available online for those that can't make it.

Tydude
01-04-2013, 02:25 PM
the 1st online class is February 26th at 6:30 PM Central time

venture
01-04-2013, 06:25 PM
Looks like some light snow moving through overnight and tomorrow morning. Shouldn't be anything major at all as none of the models are spitting out any ground accumulation.

OKCisOK4me
01-04-2013, 06:33 PM
Yeah, ol' Aaron Tuttle on his Facebook page was hinting at this last night saying that the metro area could see half an inch to 2 inches but probably a majority would see half an inch at the most.

Bunty
01-05-2013, 02:21 AM
The Norwegian Meteorological Institute, which provides online weather forecasts for most cities and towns in the world says OKC will have a bit over an inch of rain this Wednesday with temps in the mid 40s. As I recall from following in the past, they're not real accurate. You can get their forecasts at yr.no (http://yr.no). But have to put up with metric only measurements used there.

venture
01-06-2013, 02:20 AM
Quick update from the 00Z GFS tonight.

6AM Weds through Midnight Friday morning - Looks like some areas could see a decent amount of precip. This feature has been present for at least 8 runs now, but there are variations in strength and placement. We are looking at 100% rain right now. Best chance will be over Eastern 1/2 of Oklahoma. Amounts could approach an inch in several spots, maybe more in isolated areas.

Next chance would be around Monday the 14th. Right now the storm placement is east of us, over mostly SE OK. This would be a mostly snow system. A very large arctic outbreak looks like is on tap for this time frame. Could see a very good accumulating snow over SE OK all the way up to the Lower Great Lakes.

Finally another system moves through around Sunday the 20th. This would be mostly snow as well. Best chance of precip is over Eastern OK up through the Great Lakes.

As with anything, we just have to monitor the trends with these forecasts and see what happens.

Bunty
01-06-2013, 08:10 PM
The amount of rain yr.no has predicted of OKC has fallen under an inch.

OKCisOK4me
01-06-2013, 11:40 PM
Aaron Tuttle is calling for a gully washer...

venture
01-07-2013, 12:54 AM
Aaron Tuttle is calling for a gully washer...

People still listen to him? :-P

venture
01-07-2013, 01:23 AM
Couple thoughts on the upcoming weather..."events".

Have some rain coming up this week. Yawn. Not looking like a drought buster at all, but I guess it can always change. Half to one inch of rain in the Western 1/3rd of the state. Then an area of less than a half inch of rain mainly along and north of I-44 (and east of US 281), including most of the metro area. Then south and east of I-44 looks like 1-2 inches of rain and maybe some isolated higher amount the further SE you go.

Next system is for Sunday. Looks like this will be mainly snow, if the 00Z GFS is right. It isn't completely consistent with the placement and even having snow. Here is how they break down run by run...and this is all total accumulation by midday Sunday.

06Z Sat - 1-4" Western OK
12Z Sat - No snow.
18Z Sat - <1" SE OK, highest snow band over Central AR (3-6")
00Z Sun - 2-4" SE OK, main snow band W and C AR through SE OK into NE TX.
06Z Sun - 2-5" Central and Eastern OK, two main snow bands one TUL to LAW, other over SE OK.
12Z Sun - 1-2" over Central AR, no other snow areas.
18Z Sun - No snow.
00Z Mon - Snow along and SE of I-44, generally 2-5" with areas of up to 6" in South Central OK and also in Northern AR.

We'll see what happens. Things are bouncing around a lot as you can tell, so no one can say either way what will happen.

OKCisOK4me
01-07-2013, 03:13 AM
People still listen to him? :-P

His sense of humor is what drove me to 'like' him on Facebook, lol.

venture
01-07-2013, 03:43 PM
Before anyone brings it up, Damon Lane made a comment on KOCO's blog yesterday about some major cold snap in two weeks. What he didn't really point out, is that it was a run from Jan 4th (a few days old) and that major cold snap is no where to be found.

So don't worry much. At this rate he is bound to follow Aaron Tuttle as a "Facebook Forecaster". :)

damonsmuz
01-07-2013, 03:49 PM
11

Uncle Slayton
01-07-2013, 06:30 PM
Before anyone brings it up, Damon Lane made a comment on KOCO's blog yesterday about some major cold snap in two weeks. What he didn't really point out, is that it was a run from Jan 4th (a few days old) and that major cold snap is no where to be found.

So don't worry much. At this rate he is bound to follow Aaron Tuttle as a "Facebook Forecaster". :)

Dammit. AccuJackWeather has been talking about a "cold dam" for several days, supposedly as a result of sudden stratospheric warming. They have the jet firmly anchored in CenTex by week 3 of January with reinforcing cold waves behind it.

Can we just one time have an apocalyptic weather forecast that stands up to scrutiny and wreaks untold havoc?

venture
01-07-2013, 06:57 PM
Dammit. AccuJackWeather has been talking about a "cold dam" for several days, supposedly as a result of sudden stratospheric warming. They have the jet firmly anchored in CenTex by week 3 of January with reinforcing cold waves behind it.

Can we just one time have an apocalyptic weather forecast that stands up to scrutiny and wreaks untold havoc?

In about 12 hours a burning ball of fire and gas that will eventually engulf the planet will appear to all humanity.

How's that?

Plutonic Panda
01-07-2013, 08:23 PM
In about 12 hours a burning ball of fire and gas that will eventually engulf the planet will appear to all humanity.

How's that?Whoa. I was thinking something like a 3 week long, 100ft. blizzard with 350mph winds and a few snow tornados here and there. But I like your style!!!!! lol

Oh, and of course -85 temperatures in the fahrenheit variety ;)

Uncle Slayton
01-07-2013, 08:23 PM
In about 12 hours a burning ball of fire and gas that will eventually engulf the planet will appear to all humanity.

How's that?

Michael Moore get the pu pu platter again?

If I got a choice, I'd prefer a frozen apocalypse, but, to paraphrase Ron White, "hit somethin hard, I don't wanna limp away from this apocalypse."

venture
01-07-2013, 08:45 PM
Hey...what I said was true. Just that eventually is about 4 billion years down the road when our star turns into a Red Giant. :)

Plutonic Panda
01-07-2013, 09:19 PM
Hey...what I said was true. Just that eventually is about 4 billion years down the road when our star turns into a Red Giant. :)Unless we are hit by a quasar in the mean time.=)

Bill Robertson
01-08-2013, 09:55 AM
Dammit. AccuJackWeather has been talking about a "cold dam" for several days, supposedly as a result of sudden stratospheric warming. They have the jet firmly anchored in CenTex by week 3 of January with reinforcing cold waves behind it.

Can we just one time have an apocalyptic weather forecast that stands up to scrutiny and wreaks untold havoc?I'm very happy with the way things are going now.

Bunty
01-08-2013, 11:47 AM
Before anyone brings it up, Damon Lane made a comment on KOCO's blog yesterday about some major cold snap in two weeks. What he didn't really point out, is that it was a run from Jan 4th (a few days old) and that major cold snap is no where to be found.

So don't worry much. At this rate he is bound to follow Aaron Tuttle as a "Facebook Forecaster". :)

I don't see your point since the GFS model he's going by is dated Jan.12 to Jan. 17:

http://www.koco.com/image/view/-/18016384/highRes/1/-/15us2yi/-/gfs-t2m-anomf-west-43-png.png

OKCisOK4me
01-08-2013, 12:40 PM
Uh, that's dated the 4th thru the 17th so half of it is wrong, lol.

venture
01-08-2013, 11:59 PM
00Z runs of the GFS and NAM are pulling rain amounts back a ton. Short term HRRR also showing the bulk of rain remaining in Texas.

GFS rainfall totals show roughly 0.5-1" over SW OK, less than a half inch everywhere else.

NAM rainfall is roughly < 0.5" Northern OK, 0.5 - 1" Central OK, and 1-2" Southern/SE OK.

We'll see what happens, but wanted to pass that part on.

GFS is also still latched on to the idea of snowfall on Monday. Mind you not all members of the GFS ensemble are in agreement with this.

http://www.twisterdata.com/data/models/gfs/3/maps/2013/01/09/00/GFS_3_2013010900_F150_SNOWIN_SURFACE.png

http://www.meteo.psu.edu/~fxg1/ENSPCN72NE_0z/f150.gif

1972ford
01-09-2013, 01:33 AM
We will take anything we can get at this point just hope spring has lots of moisture in store for us

SoonerDave
01-09-2013, 02:18 PM
Okay, Venture, here's a purely speculative question for you.

Rewind to Christmas, and we were all getting twitchy about the models showing another Snowmageddon for Christmas Eve/Christmas Day, but at seemingly the last moment (okay, last few hours), the models started pulling back and keeping the system farther south in Texas...

Now, back to now...last couple of days, we've been hearing about the models showing a pretty decent rainfall event for OK, but at seemingly the last moment (okay, last few hours), (stop if you've heard this...lol) the models started pulling back and keeping the system farther south in Texas...

So, is this purely a coincidence demonstrating the insufficiency of the models (despite the fact they accurately predicted snow/rain in the general area, but missed in the specific) in that they seem to have missed in these two forecasts in rather similar ways? Or is it indicative that maybe something else in the way these storms "spin out" (for lack of a technical term) that maybe we don't entirely understand?

I'm really just getting at what at least seems like a similar forecast, similar models, departing late-game into a keep-the-rain/snow-south projection, both at the same time, sure strikes me as an odd coincidence...

Bunty
01-09-2013, 02:39 PM
Yeah, Dallas has a 100% of precipitation with "heavy rain" in the forecast this afternoon while OKC only has "showers" for tonight with a 90% chance.

venture
01-09-2013, 03:06 PM
Okay, Venture, here's a purely speculative question for you....

Now, back to now...last couple of days, we've been hearing about the models showing a pretty decent rainfall event for OK, but at seemingly the last moment (okay, last few hours), (stop if you've heard this...lol) the models started pulling back and keeping the system farther south in Texas...


I think it is just a matter of marrying oneself to a model solution and refusing to deviate. You might remember even last week I mentioned it wasn't going to be a wash out. Rain amounts fluctuated, but Central OK was never on the high end. To me it really hasn't changed much.


Yeah, Dallas has a 100% of precipitation with "heavy rain" in the forecast this afternoon while OKC only has "showers" for tonight with a 90% chance.

Percentages only refer to area coverage, not amounts. 100% of the Dallas area will see precip. 90% of the OKC area will see precip. That how those should always be read.

Anonymous.
01-09-2013, 03:12 PM
Actually the percentages used in the case of the poster above most likely refers to the dummied versions of percentiles. Those percentages are the probability or chance that precipitation will occur of the given area (in this case, Dallas or OKC).

Percentages like this, that the media gives out like "80% chance of rain on Monday" - does NOT mean 80% of the area, but rather the chance of the area receiving rain is 80%.

For sake of confusing the masses, media will often not move chance percentages concurrently with amounts. This is incorrect though, really. The real way to do a forecast is to explain to the viewers how it works. For instance, you can say there is a 100% chance of snow today - and the only thing that falls is snow flurries, this forecast was accurate - but since the common media has ruined our to view forecasting, people will think 100% chance of snow means A LOT of snow.

Hopefully this post makes sense, I have tried to explain these things in-person before, but have found it is rather difficult.

SoonerDave
01-09-2013, 03:33 PM
I've always understood the POP figures to relate to the probability of a given amount of precipitation within a given distance of a designated point within a designated amount of time, eg 20% POP in OKC means a one-in-five chance of measurable rain within 3 miles of any given point within whatever boundary is implied by the designation of "OKC." Not so?

I've never taken those percentages to imply a particular intensity or coverage area.

SoonerDave
01-09-2013, 03:41 PM
Okay, being too curious for my own good, I did some googling for NWS definitions on POP. Here's what I found from FAQ - What is the Meaning of (http://www.srh.noaa.gov/ffc/?n=pop)



What does this "40 percent" mean? ...will it rain 40 percent of of the time? ...will it rain over 40 percent of the area?

The "Probability of Precipitation" (PoP) describes the chance of precipitation occurring at any point you select in the area.

How do forecasters arrive at this value?

Mathematically, PoP is defined as follows:
PoP = C x A where "C" = the confidence that precipitation will occur somewhere in the forecast area, and where "A" = the percent of the area that will receive measureable precipitation, if it occurs at all.

So... in the case of the forecast above, if the forecaster knows precipitation is sure to occur ( confidence is 100% ), he/she is expressing how much of the area will receive measurable rain. ( PoP = "C" x "A" or "1" times ".4" which equals .4 or 40%.)

But, most of the time, the forecaster is expressing a combination of degree of confidence and areal coverage. If the forecaster is only 50% sure that precipitation will occur, and expects that, if it does occur, it will produce measurable rain over about 80 percent of the area, the PoP (chance of rain) is 40%. ( PoP = .5 x .8 which equals .4 or 40%. )

In either event, the correct way to interpret the forecast is: there is a 40 percent chance that rain will occur at any given point in the area.

venture
01-09-2013, 04:11 PM
Actually the percentages used in the case of the poster above most likely refers to the dummied versions of percentiles. Those percentages are the probability or chance that precipitation will occur of the given area (in this case, Dallas or OKC).

Percentages like this, that the media gives out like "80% chance of rain on Monday" - does NOT mean 80% of the area, but rather the chance of the area receiving rain is 80%.

For sake of confusing the masses, media will often not move chance percentages concurrently with amounts. This is incorrect though, really. The real way to do a forecast is to explain to the viewers how it works. For instance, you can say there is a 100% chance of snow today - and the only thing that falls is snow flurries, this forecast was accurate - but since the common media has ruined our to view forecasting, people will think 100% chance of snow means A LOT of snow.

Hopefully this post makes sense, I have tried to explain these things in-person before, but have found it is rather difficult.

Which highlights the differences in what percentages mean in weather forecasting. Neither of us are wrong, it comes down to the forecast area.

Uncle Slayton
01-09-2013, 06:21 PM
So, are we going to get snow next week or not? Flurries or otherwise.

Bunty
01-09-2013, 08:31 PM
On radar it looks like this system has spit in two as it moves north, leaving Oklahoma largely high and dry.

OKCisOK4me
01-09-2013, 10:02 PM
Yep, its just spitting out there ;-)

s00nr1
01-09-2013, 10:40 PM
The 00z NAM came in tonight with a bit of snow/sleet for Sat night-Sun am. Will need to keep an eye on this.

http://wxcaster4.com/nam/CONUS1_ETA212_SFC_ACCUM-SNOWFALL_84HR.gif

Anonymous.
01-10-2013, 01:28 PM
As the Low is moving across S OK right now, some thunderstorms are trying to pop up. What an interesting weather situation. Warm air streaming from the south east, some clearing skies over OK with a strong Low scooting right over.

venture
01-10-2013, 02:42 PM
My activity here is going to be pretty brief until the trojans are removed from the site. NAM and GFS in agreement with keeping the snow this weekend Northeast of Oklahoma for the most part.

kelroy55
01-10-2013, 04:04 PM
Drove up to Joplin this afternoon for a funeral and hit decent rain from Tulsa on and still raining.

Easy180
01-12-2013, 08:31 AM
Talking about a trace in the metro this afternoon...Sure we will only see it in the air, grass and rooftops

venture
01-12-2013, 11:12 AM
Winter Wx Adv is up for some FRZ RN and Mix Precip...

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
1052 AM CST SAT JAN 12 2013


OKZ008-012-013-018>020-024>026-029-030-130500-
/O.NEW.KOUN.WW.Y.0001.130112T1700Z-130113T0800Z/
KAY-GARFIELD-NOBLE-KINGFISHER-LOGAN-PAYNE-CANADIAN-OKLAHOMA-
LINCOLN-CLEVELAND-POTTAWATOMIE-
INCLUDING THE CITIES OF...PONCA CITY...ENID...PERRY...
KINGFISHER...GUTHRIE...STILLWATER...YUKON...EL RENO...MUSTANG...
OKLAHOMA CITY...CHANDLER...NORMAN...MOORE...SHAWNEE
1052 AM CST SAT JAN 12 2013


...WINTER WEATHER ADVISORY IN EFFECT UNTIL 2 AM CST SUNDAY...


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW...SLEET AND FREEZING RAIN...WHICH IS IN
EFFECT UNTIL 2 AM CST SUNDAY.


* TIMING: LATE THIS MORNING THROUGH LATE TONIGHT. THE HEAVIEST
WINTRY PRECIPITATION IS EXPECTED LATE THIS AFTERNOON THROUGH
THIS EVENING.


* MAIN IMPACT: WINTRY PRECIPITATION WILL CONTINUE TO DEVELOP
THROUGHOUT TODAY ESPECIALLY ACROSS NORTHEAST AND CENTRAL
OKLAHOMA. A COMBINATION OF SNOW...SLEET..AND FREEZING RAIN IS
EXPECTED. SNOW AND SLEET ACCUMULATIONS AROUND 1 TO 3 INCHES WILL
OCCUR LATER TODAY ACROSS CENTRAL AND NORTHEASTERN OKLAHOMA. IN
ADDITION...FREEZING RAIN MAY ALSO RESULT IN ICE ACCUMULATIONS
AROUND ONE TENTH OF AN INCH.


* OTHER IMPACTS: SLICK ROADWAYS WILL DEVELOP ACROSS THE REGION
TODAY. INITIALLY...BRIDGES AND OVERPASSES WILL BECOME SLICK.
LATER THIS AFTERNOON AND EVENING AS COLDER AIR MOVES INTO THE
AREA...ALL OTHER ROADWAYS WILL ALSO BECOME SLICK. MOTORISTS ARE
URGED TO USE CAUTION TODAY AND TONIGHT.


PRECAUTIONARY/PREPAREDNESS ACTIONS...


BE CAREFUL IF YOU HAVE TO TRAVEL. EVEN SMALL AMOUNTS OF ICE AND
SNOW CAN MAKE ROADS AND SIDEWALKS SLICK AND DANGEROUS.

venture
01-12-2013, 02:29 PM
Pretty good band of freezing rain and sleet now extends from Ponca to Perry to Guthrie to Mustang to Chickasha to Duncan. Movement is to the NNE.

http://www.weatherspotlight.com/radar/ktlx_br1.png

venture
01-12-2013, 03:57 PM
Light to moderate freezing rain in Norman right now. Areas mainly east of East 12th have a good glaze of ice on all elevated surfaces.

ou48A
01-12-2013, 04:36 PM
Wow, its bone dry on the NW side Norman.

kelroy55
01-12-2013, 04:37 PM
Looks like it's going to miss OKC to the east. I drove back from Joplin this afternoon and had rain most of the way until 50-60 miles from OKC

Bunty
01-12-2013, 04:58 PM
Most of the ice and snow may be all over, assuming what's in the northwest part of the state doesn't maintain intensity and move this way.

LocoAko
01-12-2013, 05:25 PM
Had a very light glaze on my car here in central Norman. Thundersnow (probably thundersleet) was reported in Shawnee just to our east.

3206

OKCMallen
01-13-2013, 02:07 PM
Aaron Tuttle posted a picture of a model projecting ~12" of snow on Wed/Thurs of this week. :tongue:

damonsmuz
01-13-2013, 03:10 PM
Looks like some serious cold air is moving in next week. Anyone surprised? Im not! :)
3207

bandnerd
01-13-2013, 04:29 PM
Aaron Tuttle posted a picture of a model projecting ~12" of snow on Wed/Thurs of this week. :tongue:

Glad to see that everyone else is saying about 52-55 and sunny on those days. I think I'll pay attention to the majority on this one.

venture
01-13-2013, 04:38 PM
Looks like some serious cold air is moving in next week. Anyone surprised? Im not! :)
3207

Indeed. Cold air with this week should just make it easier for the next batch to slide in. Though I doubt we see anything extremely cold. Of course my opinion of that is a little different than others here. Where I grew up air temps of 10 below and 40 below wind chills were pretty common. LOL

venture
01-13-2013, 04:40 PM
Glad to see that everyone else is saying about 52-55 and sunny on those days. I think I'll pay attention to the majority on this one.

Maybe he is auditioning for Morgan's new sidekick. They need more for the hype machine over there. :)

ou48A
01-13-2013, 06:03 PM
Channel 5 just mentioned they are watching for the possibility of a snow storm.
Along with a very significant cold snap next week.

venture
01-13-2013, 06:19 PM
Couple different runs to compare the temp forecasts...

18Z: TwisterData.com | GFS 2 M ABOVE GROUND TMPF Forecast (http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2013&model_mm=01&model_dd=13&model_init_hh=18&fhour=00&parameter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=loopmaps&sounding=n&output=image&view=large&archive=false)

12Z: TwisterData.com | GFS 2 M ABOVE GROUND TMPF Forecast (http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2013&model_mm=01&model_dd=13&model_init_hh=12&fhour=06&parameter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=loopmaps&sounding=n&output=image&view=large&archive=false)

As for any snow storm...right now it looks like 3 out of 16 ensemble members for the GFS are showing any precip this week.
http://www.meteo.psu.edu/~fxg1/ENSPCN72NE_18z/f126.gif

Anonymous.
01-14-2013, 06:42 PM
Arkansas into the Mississippi and Tennessee Valleys have been spoiled this season.. They have been getting an onslaught of winter storms for quite some time now. They were hit with ice and sleet today, will get an ice storm tomorrow, then later this week get a snow storm.


Why can't Oklahoma get any fun!?

>:[

catch22
01-15-2013, 01:39 AM
As I work outside all day, I am perfectly okay with no huge winter storms or regularly occurring precipitation.

Plutonic Panda
01-15-2013, 02:02 AM
As I work outside all day, I am perfectly okay with no huge winter storms or regularly occurring precipitation.Well if we got a winter storm, you wouldn't have to work outside. Capiche? lol jk ;)

catch22
01-15-2013, 02:23 AM
Well if we got a winter storm, you wouldn't have to work outside. Capiche? lol jk ;)

Actually, I would still have to. We only shut down if air to ground lightning is within 5 miles. Or if there is freezing fog.