Oklahoma Weather Discussion - February/March 2013

[venture]

I am not sure who you are talking about but I don’t have you on ignore

LOL just checking. We posted that same weather statement 3 times total. :-P lol

[Dustin]

Jon Slater is saying NW OK could get in excess of 1 foot of snow. He also said there is a possibility that the storm could move south and impact OKC.

I like that we are getting moisture, but why does it have to be snow?!?! lol

[venture]

Jon Slater is saying NW OK could get in excess of 1 foot of snow. He also said there is a possibility that the storm could move south and impact OKC.

I like that we are getting moisture, but why does it have to be snow?!?! lol

He's just relaying the NWS's thoughts at this point.

To the second point...its winter, deal with it. :-P I really wish people understood how much better it is for us if we can get a good snow pack to help replenish the ground moisture. Heavy rain just runs off at this point. The more we can moisten up the near surface soil, the better it'll absorb the rain we get from storms this spring.

NWS Statement

...CONFIDENCE IS INCREASING THAT A DANGEROUS WINTER STORM WILLAFFECT OKLAHOMA SUNDAY NIGHT THROUGH TUESDAY MORNING...


A STRONG WINTER STORM WILL AFFECT OKLAHOMA SUNDAY NIGHT THROUGH TUESDAY
MORNING. RAIN AND THUNDERSTORMS ARE EXPECTED TO QUICKLY CHANGE TO SNOW
ACROSS NORTHWEST AND WESTERN OKLAHOMA SUNDAY NIGHT AND OVER CENTRAL
SECTIONS OF OKLAHOMA ON MONDAY.


ACCUMULATING SNOW WILL BE LIKELY SUNDAY NIGHT THROUGH TUESDAY MORNING...
WITH THE BEST CHANCES ACROSS NORTHWESTERN OKLAHOMA WHERE OVER A FOOT
OF SNOWFALL CANNOT BE RULED OUT. STRONG WINDS WILL ALSO CAUSE BLOWING
AND DRIFTING OF SNOW WHICH WILL REDUCE VISIBILITIES AND CREATE
TREACHEROUS DRIVING CONDITIONS.


SOME QUESTIONS REMAIN ON THE EXACT PATH OF THE STORM SYSTEM AND ITS
HEAVIEST SNOW. FOLLOW THE LATEST INFORMATION AT WEATHER.GOV/NORMAN.

[Dustin]

He's just relaying the NWS's thoughts at this point.

To the second point...its winter, deal with it. :-P I really wish people understood how much better it is for us if we can get a good snow pack to help replenish the ground moisture. Heavy rain just runs off at this point. The more we can moisten up the near surface soil, the better it'll absorb the rain we get from storms this spring.

NWS Statement

I understand the benefits of a good snow pack...

I just don't like anything frozen to be on the road. My mom is a nurse and she has to go to work no matter what. I just worry about her when it snows.

[ou48A]

Gary England referred to this storm as being Life Threating. I was glad to hear him put it like that.

If you are caught out in it and away from a significant heated shelter it can be life threating.

Wherever this hits it will get very bad very quickly causes some folks to be stuck exactly where they are for a day or 2. In places where there is an existing snow pack roads could drift shut in just a matter of minutes with the high winds. You don’t want to be driving anywhere where there is an existing snow pack when this starts.
Be where you need to be with provisions well in advance. There will likely soon be a big run on the grocery stores.

[Dustin]

David Payne - "Winter storm update.. New data coming in continues to show Okla. nailed w heavy snow/blizzard. Arrives this Monday! Prepare this weekend!"

Also, remember to PANIC!!!

[Bunty]

Gary England referred to this storm as being Life Threating. I was glad to hear him put it like that.

If you are caught out in it and away from a significant heated shelter it can be life threating.

Was he worried about it for northwestern Oklahoma, or for Oklahoma City?

[Dustin]

Harper, Woods, Alfalfa, Grant, Kay, Ellis, Woodward, Major, Kingfisher, Logan, Payne and Beckham County under Winter Storm watch now.

[Bunty]

So, far NOT Oklahoma County. It includes most of the NW quadrant of Oklahoma.

WINTER STORM WATCH:

Areas affected: Alfalfa; Beckham; Blaine; Custer; Dewey; Ellis; Garfield; Grant; Harper; Kay; Kingfisher; Logan; Major; Noble; Payne; Roger Mills; Wa****a; Woods; Woodward

Instructions: Keep up with the latest weather information...especially if you plan to travel.

Message summary: ...winter storm watch in effect from sunday evening until early tuesday...
* timing: late sunday evening until sunrise tuesday
* main impact: more than a foot of snow is possible in northwest oklahoma. More than four inches of snow is possible north of i-40 and west of i-35.
* other impacts: gusty northwest wind will cause blowing and drifting snow.

[Easy180]

Sunny and 60 on Sunday should help with ground temps....Worst thing will be the blowing snow while driving around here unless the storm shifts

[venture]

12Z NAM Discussion

3PM to 6PM Sun: First chance of precip arrives in the form of storms in SW OK. Instability will permit some of the storms to be strong, perhaps just barely into severe limits. No frozen precip outside of hail.

6PM to 9PM: Storms fire along boundary throughout western OK. Colder air is also wrapping in quickly so anything north of I-40 at this point will be mixing with or changing to snow/graupel/sleet. Some areas could see 0.1 to 0.5" of precip, highest amounts around Woodward down to north of ElK City.

9PM to 12AM Mon: Line of precip marches east to along the I-35 corridor and back to the west. Generally 0.1 amounts here, but higher back into NW OK where amounts could be 0.5 to 0.7" of precip. Looks like still generally a mix bag in NW OK, all rain here.

12AM to 3AM: Line pushes east of I-35, precip ends (for now) west of I-35. Light amounts...0.1 to 0.3" from Bartlesville to Ada. All liquid.

3AM to 6AM: Rain eastern OK, wrap around slowly moving into NW OK. Very light snow there, maybe an inch.

6AM to 9AM: Wrap around snow still in far NW OK, only around an additional inch at this point still.

9AM through rest of Monday... Very light wrap around in NW OK, dry elsewhere.

So with this run, it would eliminate the winter storm threat for much of OK. New GFS will be in in roughly an hour, so we can compare to that. Historically the NAM has been shifting the heavy snow to the NW in each of the last 3 runs. I'm not buying everything yet until we see the other models to the same. Just something to keep in the back of our heads.

[venture]

Latest update from Norman...

...DANGEROUS WINTER STORM EXPECTED TO IMPACT OKLAHOMA SUNDAY NIGHT
THROUGH TUESDAY MORNING...


A POTENT WINTER STORM SYSTEM WILL MOVE INTO WESTERN OKLAHOMA
SUNDAY NIGHT...AND EXIT THE REGION BY TUESDAY MORNING. RAIN AND
THUNDERSTORMS ARE EXPECTED TO QUICKLY CHANGE TO SNOW ACROSS
NORTHWEST AND WESTERN OKLAHOMA SUNDAY NIGHT AND OVER CENTRAL
SECTIONS OF OKLAHOMA MID TO LATE MONDAY MORNING.


ACCUMULATING SNOW WILL BE LIKELY SUNDAY NIGHT THROUGH TUESDAY
MORNING... WITH THE BEST CHANCES ACROSS NORTHERN AND WESTERN
OKLAHOMA...WHERE 10 TO 12 INCHES OF SNOW WILL BE POSSIBLE. FURTHER
SOUTH...FROM WEST CENTRAL OKLAHOMA THROUGH THE OKLAHOMA CITY
METRO...3 TO 5 INCHES OF SNOW WILL BE POSSIBLE. STRONG WINDS WILL
ALSO CAUSE BLOWING AND DRIFTING OF SNOW...AND NEAR WHITEOUT
CONDITIONS...WHICH WILL REDUCE VISIBILITIES AND MAKE FOR VERY
DANGEROUS TRAVEL CONDITIONS.


SOME QUESTIONS REMAIN ON THE EXACT PATH OF THE STORM SYSTEM AND
ITS HEAVIEST SNOW. FOLLOW THE LATEST INFORMATION AT
WEATHER.GOV/NORMAN.

[venture]

I wanted to bring in some more information when it comes to the 12Z NAM run which essentially takes this storm north and spares most of Oklahoma. Here is the HPC model discussion regarding this solution...

...UPPER-LEVEL TROUGH/FRONTAL BNDRY INITIALLY OVER THE WESTERN
STATES...
...SURFACE LOW PRESSURE SYSTEM DEVELOPING ACROSS THE SRN PLAINS ON
SUNDAY...


THE NAM SOLUTION LIES WITHIN THE MODEL CONSENSUS THROUGH EARLY
SUNDAY AS THE TROUGH CROSSES THE INTERMOUNTAIN WEST. BY LATE
SUNDAY AS THE SYSTEM BEGINS TO EXIT THE ROCKIES...DIFFERENCES
BEGIN TO EMERGE. THE TROUGH IS FORECAST BY ALL GUIDANCE TO CLOSE
OFF INTO AN UPR-LVL LOW BY SUNDAY AFTERNOON. THE NAM DOES NOT DIG
THE TROUGH AS FAR SOUTH AS IT CLOSES OFF...WHICH RESULTS IN THE
CLOSED UPR-LVL LOW TRACKING A COUPLE HUNDRED MILES FARTHER NORTH
ACROSS THE PLAINS RELATIVE TO OTHER GUIDANCE. THE NAM ALSO SHOWS
THE SURFACE LOW FARTHER NORTH THAN CONSENSUS. IT IS INTERESTING TO
NOTE THAT THE 00Z ECMWF ENSEMBLE MEAN DOES DEPICT A LARGER CLOSED
CONTOUR WHICH ENCLOSES THE CENTER OF THE NAM UPR-LVL LOW. THIS
INDICATES THAT A SUBSTANTIAL NUMBER OF THE ECMWF ENSEMBLE MEMBERS
SHOWED THIS MORE NORTHERN LOW...AND THE SOLUTION CANNOT YET BE
DISCOUNTED.

The main theme with this is that the NAM 12Z is outside of the current consensus of all the models put together. However, a good number of members of the Euro model ensemble are picking up on the more northern option and this solution. So the 12Z NAM isn't completely out to lunch on its own with this. The GFS is running now and that will give us an idea if this is a late trend developing or just something we need to watch.

[LocoAko]

Norman also mentioned a possible upgrade to blizzard watches for parts of the forecast area.

[venture]

Norman also mentioned a possible upgrade to blizzard watches for parts of the forecast area.

At this point that is almost a given. Winds will meet the criteria (35mph sustained) over Western OK. Keep in mind Blizzard watches/warnings has little relation to actual snowfall amounts. It is going to come down to wind and visibilities if there is an upgrade. Right now it looks decent to do the upgrade. 12Z GFS discussion incoming...

[Decious]

Given the uncertainty in the models... the thermal profiles being right on the edge regarding precip type... the possibility of a strengthening system bringing in more cold air faster while also perhaps creating a more pronounced warm nose etc... I think that anyone within 100 miles north or south of whatever advisories are issued should stay aware of the situation. Anything could happen. IMO.

[venture]

12Z GFS Discussion

Comparing this model to the 12Z NAM, they are pretty different. Up until Sunday AM they are with each other and then they diverge. NAM goes north, GFS digs the closed upper low in more and drags it through the body of Oklahoma. This storm really starts to get cranking while over Oklahoma so points to the East are going to see another significant storm it appears, but back to us.


6PM to 9PM Sun: Precip arrives in Western OK. Amounts very light at this time, maybe up to 0.1". Appears to be mainly liquid.

9PM to 12AM Mon: Precip increases a bit in NW OK, some light drizzle might be streaming in from the south into SW OK. Should start to see mixing and possible change over out in the Panhandle and extreme NW OK. Otherwise still mostly liquid. Amounts 0.1 to 0.4".

12AM to 3AM: Precip lightens up a bunch here with light areas of precip roughly I-35 and back west. All under 0.1". At this point all snow NW OK, rain elsewhere.

3AM to 6AM: Precip starts to increase a bit west of a Tulsa to Durant line, and then roughly east of Lawton to Guthrie to Perry line. Amounts around 0.1" in these areas. Another band forming out in the panhandles. Mostly all liquid precip still as temps will be pretty warm.

6AM to 12PM: Precip cranks up during this time block. West 1/3rd is 0.1 to 0.3", Central Third 0.3 to 0.8", Eastern Third 0.1" to 1"...the bullseye is roughly in an area east of Ponca to Norman to Ada, and then West from Ada to Tulsa to Bartlesville. All liquid except for the area north of a line from Frederick to El Reno to Perry to northern Osage County (can't think of a city up there LOL). Some areas out there could see a good 3-5" of snow during the time, 1-3" further South and East you get. Surface winds will be around 25-30 kts over West Central OK which would star to push up against blizzard criteria.

12PM to 6PM: First band is in Eastern OK, lighter precip/dryslotting over Central, and then 2nd band over Western third of OK. 0.1 to 0.4" west, around 0.1" central, and up to 1" east. Everything west of a Miami to Tulsa to Durant line should be snow at this point. Surface winds forecast around 20-25kts, so a bit lighter but still will cause decent blowing/drifting. Snowfall amounts look like less than an inch Central to 3-5" SW, and 6-8" NW by this point.

6PM to 12AM Tue: All snow statewide at this point. Winds generally around 20kts. Precip starts to exit pretty quickly. Dry west, less than 0.1" central, and around 0.1" out east...except far NE OK may still see some heavier precip. Storm total snow amounts by this point don't look much different than stated above. Generall...3-5" SW, 6-8" NW, 3-6" NC, ~1" Central, <1" SC, 0" NE, ~1" SE. Important to note far NE OK is the last to see change over, reducing their chance for accumulating snow.

Keep in mind ground temps in some areas will still be warm and surface temps may not be below freezing during this event, so melting plays in again of course. Another fun one to watch.

[venture]

Given the uncertainty in the models... the thermal profiles being right on the edge regarding precip type... the possibility of a strengthening system bringing in more cold air faster while also perhaps creating a more pronounced warm nose etc... I think that anyone within 100 miles north or south of whatever advisories are issued should stay aware of the situation. Anything could happen. IMO.

This one is cake when you look at temperature profiles when compared to the last 2 systems. We aren't going to be riding the line nearly as closely as we were the last two systems. Biggest thing right now is going to be the track of the system.

[venture]

Updated Model Discussion from HPC...

...UPPER-LEVEL TROUGH/FRONTAL BNDRY INITIALLY OVER THE WESTERN
STATES...
...SURFACE LOW PRESSURE SYSTEM DEVELOPING ACROSS THE SRN PLAINS ON
SUNDAY...

PRELIMINARY PREFERENCE: GFS/00Z ECMWF/00Z ECMWF ENSEMBLE MEAN BLEND
CONFIDENCE: BELOW AVERAGE

THE NAM SOLUTION LIES WITHIN THE MODEL CONSENSUS THROUGH EARLY
SUNDAY AS THE TROUGH CROSSES THE INTERMOUNTAIN WEST. BY LATE
SUNDAY AS THE SYSTEM BEGINS TO EXIT THE ROCKIES...DIFFERENCES
BEGIN TO EMERGE. THE TROUGH IS FORECAST BY ALL GUIDANCE TO CLOSE
OFF INTO AN UPR-LVL LOW BY SUNDAY AFTERNOON. THE NAM DOES NOT DIG
THE TROUGH AS FAR SOUTH AS IT CLOSES OFF...WHICH RESULTS IN THE
CLOSED UPR-LVL LOW TRACKING A COUPLE HUNDRED MILES FARTHER NORTH
ACROSS THE PLAINS RELATIVE TO OTHER GUIDANCE. THE NAM ALSO SHOWS
THE SURFACE LOW FARTHER NORTH THAN CONSENSUS. THE GFS SOLUTION
LIES RELATIVELY CLOSE TO THE 00Z ECMWF/00Z UKMET. IT IS
INTERESTING TO NOTE THAT THE 00Z ECMWF ENSEMBLE MEAN DOES DEPICT A
LARGER CLOSED CONTOUR WHICH ENCLOSES THE CENTER OF THE NAM UPR-LVL
LOW. THIS INDICATES THAT A SUBSTANTIAL NUMBER OF THE ECMWF
ENSEMBLE MEMBERS SHOWED THIS MORE NORTHERN LOW...AND THE SOLUTION
CANNOT YET BE DISCOUNTED. AT THIS POINT...WILL RECOMMEND A BLEND
OF THE GFS/00Z ECMWF/00Z ECMWF ENSEMBLE MEAN. THIS REPRESENTS A
CONSENSUS SOLUTION WITH AN ALLOWANCE FOR THE POSSIBILITY OF A
SLIGHTLY FARTHER NORTH SOLUTION IN THE DIRECTION OF THE NAM.

[Decious]

This one is cake when you look at temperature profiles when compared to the last 2 systems. We aren't going to be riding the line nearly as closely as we were the last two systems. Biggest thing right now is going to be the track of the system.

That's good to hear. So you feel pretty good about the model's grasp of when/where the system will close off and intensify? It looks like it may begin to occlude and wrap warm air pretty far around the low. I'm still learning this stuff so feel free to set me straight whenever it's necessary. I'm learning a lot in these weather treads. :-)

[OKCisOK4me]

Danielle Dozier gives her .02 cents:

Dangerous winter storm sets its eyes on Oklahoma - Oklahoma City - OKC - KOCO.com

Little surprise at the end of her article...

[venture]

That's good to hear. So you feel pretty good about the model's grasp of when/where the system will close off and intensify? It looks like it may begin to occlude and wrap warm air pretty far around the low. I'm still learning this stuff so feel free to set me straight whenever it's necessary. I'm learning a lot in these weather treads. :-)

Honestly I think the models are still lost. LOL What can you do though. 12Z GFS seems to take the surface low south/along Red River. Which is usually good for us. The upper low is pretty much going to go in a straight line from Wichita Falls NE to Fayetteville, AR. I personally would like to see it better stacked with the surface low to give us a better shot at the heavier precip. We'll see how things work out. It is hard to commit to any particular model solution at this point. HPC is pretty much saying the 12Z runs are borderline worthless and sticking with the 00Z runs. I guess it is wait and see when the 18Z run comes out.

[Anonymous.]

This is a tough forecast in terms of track. I have been calling for the closed-off low play since Thursday - and the GFS wants to make it happen. The NAM seems plausible at this point and I could see this dry-slotting OK, save the panhandle.

Tonight we should have a better idea if the NAM is legit or just trying to toss in a wrench. Trends this winter have been NAM shifts south at the last minute and GFS totally nailed the last storm.


As of right now I side with the GFS in terms of track - I still think it is getting a poor handle on temperatures. Ground temperatures will go up with the southerly flow of moist, warm air tomorrow - but we have had very hard freezes the last few days and the ground is chilled with moisture below the surface. I don't see nearly as much melting as the previous two storms mainly due to this reason alone. This storm is also different in that, it basically is a make or break type storm of either getting large accumulation of snow over a small area, or you see little to nothing. The last two storms have been considerably more broad. If this does indeed come out as closed off low, watch out [whoever it tracks over].

[Decious]

@ Venture: Lol! I agree. Whaddaya gonna do? That's interesting though that the latest runs are being pretty much discounted by the HPC... simply because the latest models have better RAOB sampling than the former. They're doing some weird things... like the NAM moving the snow field north while the low tracked a little further south... it's weird. You've been pretty dead on regarding the last couple systems though so I thought I'd ask what you thought. I'm a musician by trade and a weather junkie since I was 4 so... it's fascinating to me. Thanks again sir.

[venture]

Anon - Pretty much agree with all you are saying. I've been liking how GFS actually has done well with the last couple of systems. I also hate last minute changes in models, but we'll see what happens.

Decious - Yeah you would think the 12Z models would be nailing it since they are getting the upper air data, but who knows. We'll see what 18Z and 00Z show and see if we can establish a trend. I really wouldn't be shocked to see Norman drag the WSW further south a couple more tiers of counties to account for the GFS and more southerly track. After all...it is a watch.