Oklahoma Weather Discussion - February/March 2013

[venture]

Quick look via the 12Z GFS...

Precip Chances
- Thursday AM through early Sunday morning. Won't be a nonstop rainfall, but looks like some parts will get a decent amount. Trace to 0.20" western third of OK, 0.4-0.6" Central third, 0.8 to 1.75" Eastern third. Rain will end from west (Saturday) to east (Sunday).
- Thursday 28th through early Saturday 30th morning. Same scenario as before...best rain chances here will be on Thursday/Friday. Mostly light amounts.
- Sunday 31st - mostly Eastern OK only.

Storm Chances
- Thursday 21st: Western OK
- Friday 22nd: Central, South Central, and SE OK. Some severe.
- Saturday 23rd: Far SE OK, Some severe.
- Thursday 28th: Western half of OK. Some severe NW.
- Friday 29th: Eastern half of OK. Some severe.
- Saturday 30th: Eastern half of OK. Some severe.

Accumulating Snow (areas near these might see mixing, but no substantial accumulations)
- Thursday: Far NE OK (2-4")
- Saturday 23rd: Western PH (~1" early), I-44 area from OKC to MO border (< 1" to 3" near KS line)
- Monday 1st: Far NE OK (slight chance)

[Anonymous.]

GFS keeps trending towards a snow event at least in NW and N OK. Trying to sneak some down towards central, but it looks really similar to all the setups from this winter.


This is for Sunday, btw.

[kelroy55]

Don't need any snow... Riding the bike (motorcycle) down to Dallas Friday and coming back Sunday.

[Anonymous.]

Well I hope you have a pancho.

[kelroy55]

Well I hope you have a pancho.

Oh yeah... I have rain gear and cold weather gear but that doesn't mean I like riding in it.

[OKCisOK4me]

Don't need any snow... Riding the bike (motorcycle) down to Dallas Friday and coming back Sunday.

He said NW and N Oklahoma... you goin the opposite way buddy...

[Anonymous.]

Decent looking chance of rain Thursday into Friday.

Better chance on Saturday (initial severe potential) into Sunday. [Winter weather trending more towards unlikely]


Long range looks like a pretty active pattern is setting up over the next few weeks. Severe weather looks probable scattered throughout.

[kelroy55]

He said NW and N Oklahoma... you goin the opposite way buddy...

I know but there's still a good chance of rain here and it will be cold.

[OKCisOK4me]

I know but there's still a good chance of rain here and it will be cold.

If ya leave tomorrow you'll have awesome riding weather

[venture]

Slight Risk of severe weather today over a very small part of Southern OK and Northern Texas

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT THU MAR 21 2013

VALID 211200Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR A PART OF N-CNTRL TX/FAR
S-CNTRL OK LATE AFTERNOON/EARLY EVENING...

...SYNOPSIS...
A LARGE-SCALE UPPER-LEVEL TROUGH WILL REMAIN ANCHORED ACROSS THE
NORTHEAST. A SERIES OF SHORTWAVE IMPULSES WILL EFFECTIVELY
UNDERCUT/WEAKEN A MID-LEVEL RIDGE CENTERED OVER THE NRN PLAINS...AS
A LARGE-SCALE TROUGH DEVELOPS ACROSS THE NORTHWEST. ONE OF THE
SHORTWAVE IMPULSES SHOULD APPROACH THE SRN PLAINS BY
AFTERNOON...WITH A STRENGTHENING MID-LEVEL JET ACROSS NRN/CNTRL TX.
AT THE SURFACE...A WEAK LEE CYCLONE SHOULD PROGRESS SEWD ACROSS THE
TX PANHANDLE INTO NWRN TX BY EARLY EVENING. DRYLINE WILL ARC S/SWWD
TOWARDS THE EDWARDS PLATEAU...WHILE A QUASI-STATIONARY FRONT WILL
EXTEND E OF THE CYCLONE NEAR THE RED RIVER TO THE ARKLATEX. A COLD
FRONT WILL SWEEP SWD ACROSS THE SRN HIGH PLAINS TONIGHT.

...RED RIVER VALLEY OF THE SOUTH...
A STRENGTHENING LLJ OVER THE SRN PLAINS THIS MORNING WILL AID IN THE
POLEWARD TRANSPORT OF A MODERATELY MOIST AIR MASS FROM THE LOWER RIO
GRANDE VALLEY /CHARACTERIZED BY PW VALUES OF 1-1.25 INCHES PER WED
EVENING RAOB AND GPS DATA/. THIS SHOULD YIELD SURFACE DEW POINTS
INCREASING INTO THE LOWER 50S BY LATE-AFTERNOON NEAR THE RED RIVER
IN N-CNTRL TX WITHIN A NARROW WARM/MOIST SECTOR. WITH POST-DRYLINE
SURFACE TEMPERATURES EXPECTED TO REACH THE LOWER TO MIDDLE 80S...CIN
WILL WEAKEN AND SUFFICIENT CONVERGENCE SHOULD EXIST FOR ISOLATED
TSTM DEVELOPMENT IN N-CNTRL TX BETWEEN 21-00Z. THIS REGION SHOULD
LIE JUST N OF THE MID-LEVEL JET...WITH ELONGATED HODOGRAPHS
FAVORABLE FOR ROTATING UPDRAFTS AND SPLITTING CELLS.

THE BULK OF MODEL GUIDANCE INDICATE THAT MLCAPE SHOULD ONLY REACH
AROUND 500 J/KG. THIS APPEARS TO BE THE PRIMARY LIMITING FACTOR TO
MORE ROBUST SEVERE POTENTIAL. NEVERTHELESS...WITH STEEP MID-LEVEL
LAPSE RATES AMIDST 50-60 KT EFFECTIVE SHEAR...A LIMITED
SPATIOTEMPORAL WINDOW SHOULD EXIST FOR A FEW SURFACE-BASED DISCRETE
SUPERCELLS WITH A PRIMARY RISK OF ISOLATED LARGE HAIL. SURFACE-BASED
TSTMS WILL WEAKEN AFTER SUNSET AS MLCIN INCREASES WITH THE ONSET OF
NOCTURNAL COOLING. HOWEVER...PERSISTENT LOW-LEVEL WAA/GRADUAL
MOISTENING AROUND 850 MB SHOULD YIELD INCREASING NOCTURNAL TSTM
COVERAGE ACROSS PARTS OF SRN/ERN OK TO THE ARKLATEX. A FEW MARGINAL
HAIL EVENTS ARE POSSIBLE WITHIN THIS REGIME AMIDST A CLUSTERED
CONVECTIVE MODE.

..GRAMS/LEITMAN.. 03/21/2013

[woodyrr]

Does anyone have any insight as to what the models are predicting for between OKC and Wichita, KS on Sunday: Snow and ice accumulations, road conditions?

[kelroy55]

If ya leave tomorrow you'll have awesome riding weather

LOL it's looking better up here but worse down there. If this wasn't a benefit event for a girl I know that has cancer I wouldn't go.

[OKCisOK4me]

LOL it's looking better up here but worse down there. If this wasn't a benefit event for a girl I know that has cancer I wouldn't go.

Take to Amtrak. Ride the rails. Im guessing you don't want to rent a car. Definitely a good cause

[kelroy55]

Take to Amtrak. Ride the rails. Im guessing you don't want to rent a car. Definitely a good cause

I have a jeep and if it's raining hard I'll take it but it's a Poker Run and would prefer to have the bike. Getting wet is nothing compared to what she's already gone through.

[kelroy55]

Why does Ch. 9 say 60% of rain and 40 degrees for Sunday when everybody else is saying 20% or less and partly cloudy?

[venture]

Rain with a couple of imbedded storms with small hail moving through right now ahead of the warm front. All this should push out in the next couple of hours. Then we'll see storms refire along the cold front this evening. Best chance for severe weather is in a small area of South Central OK.

Next chance of rain is on Saturday through Sunday. Amounts look relatively light with most precip out of the area by early Sunday morning. Accumulating winter precip chances look like they'll be confined to the northern tier of counties and amounts generally less than 1" if anything. I will say that upper air temps will allow for some snow in Central OK if any precip lags behind overnight Saturday into Sunday. Not expecting anything that would stick though.

[venture]

New SPC site is up for preview...seems to have a ton of information and might be too busy for many: NOAA/NWS Storm Prediction Center

[venture]

MESOSCALE DISCUSSION 0290
NWS STORM PREDICTION CENTER NORMAN OK
0525 PM CDT THU MAR 21 2013

AREAS AFFECTED...NWRN TX INTO SWRN OK

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 212225Z - 220100Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED THUNDERSTORMS MAY FORM BY AROUND 00Z FROM NWRN TX
INTO SWRN OK WITH A MARGINAL WIND AND HAIL THREAT. HOWEVER...SEVERE
POTENTIAL IS NOT EXPECTED TO WARRANT A WATCH.

DISCUSSION...VISIBLE SATELLITE SHOWS HIGH BASED CU IN THE DEEPLY
MIXED AIR MASS ACROSS THE TX PANHANDLE INTO NWRN TX AND RECENT
SURFACE OBSERVATIONS INDICATE AN INCREASE IN WLY WIND GUSTS. TO THE
E...A DRYLINE WAS LOCATED FROM SJT TO JUST E OF ABI TO NEAR SPS.
WHILE A COOL A CLOUDY AIR MASS EXISTS E OF THE DRYLINE...A NARROW
ZONE OF HEATING WITH UPPER 40S TO LOWER 50S DEWPOINTS HAS RESULTED
IN A WEAK INSTABILITY AXIS.

AS FORCING WITH THE SHORTWAVE TROUGH AND CONVERGENCE
INCREASE...ISOLATED STORMS WILL BE POSSIBLE. GIVEN ONLY WEAK
INSTABILITY...WIDESPREAD SEVERE IS NOT ANTICIPATED. RECENT VISIBLE
IMAGERY SHOWS TCU NW OF MWL...WHICH IS THE MOST LIKELY AREA FOR AN
ISOLATED HIGH BASED SUPERCELL TO FORM. IF THIS OCCURS...HAIL AROUND
SEVERE CRITERIA AS WELL AS STRONG WIND GUSTS WILL BE POSSIBLE.

FARTHER N INTO OK...SLIGHTLY STEEPER MIDLEVEL LAPSE RATES WILL
EXIST...AND HIGH RESOLUTION MODELS INDICATE SOME HIGH BASED
CONVECTION. THE COMBINATION OF STRONG SHEAR AND STEEP LAPSE RATES
WILL TEND TO MAXIMIZE THUNDERSTORM POTENTIAL...BUT SEVERE POTENTIAL
SHOULD BE RELATIVELY LOW GIVEN LACK OF MOISTURE.

..JEWELL/KERR.. 03/21/2013

[Anonymous.]

Chances for meaningful precipitation seem to be dying with every run....

Cold and dry looks to be the new theme this weekend.

[venture]

Mmmhmm. NAM is pretty much bone dry now. GFS isn't looking all that better. Hopefully April and May are wet or this is going to be a long summer.

[venture]

So. We have two different model solutions here from the 12Z runs. One is craptastic and the other is...more probable. Let's go with the one that I currently feel is out to lunch in la la land.

GFS 12Z
It has trended much further south with the cold air and precip. I'm not buying this one at all, but I'll still share so we aren't completely caught off guard.
Through 10PM this evening - light rain around nothing major. Precip increases some out west, but mainly still back in the TX PH. Upper air temps plenty warm, no issue...moving on.
By 1AM - Upper air temps cool some, but still above freezing from 1500' and down. However, GFS pulls in colder air out west changing rain over to snow where we could see 1-3" of accumulation (according to this model) in West central and NW OK.
By 4AM - Upper air is will below freezing all the way down. Light to moderate precip will be moving through Central and Northern Oklahoma. Some areas could see a quarter to half inch of precip. For the areas below freezing this could mean 2-4" of snow, some places higher - all before ground melt.
By 7AM - Precip is out of the area and just some lingering flurries are left.

So that's the GFS...now the NAM.

Air temps pretty much on the same wave length as GFS, just moisture being the big difference. Could see some light rain/snow kick in around 10PM this evening and continue until about 4AM. Any snow that falls likely won't stick and looking at less than 1" of accumulations in most areas. Could see 1-2" far NW and northern OK...but not really much more than that.

So believe which one you want.

[venture]

Winter Weather Advisory is out for far NW OK

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
1217 PM CDT SAT MAR 23 2013


OKZ004>006-009-010-240500-
/O.NEW.KOUN.WW.Y.0006.130324T0000Z-130324T0500Z/
HARPER-WOODS-ALFALFA-ELLIS-WOODWARD-
INCLUDING THE CITIES OF...BUFFALO...ALVA...CHEROKEE...ARNETT...
WOODWARD
1217 PM CDT SAT MAR 23 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND BLOWING SNOW WHICH IS IN EFFECT FROM
7 PM THIS EVENING TO MIDNIGHT CDT SUNDAY.




* TIMING: SATURDAY EVENING.


* MAIN IMPACT: BLOWING SNOW WILL REDUCE VISIBILITY. TWO TO THREE
INCHES OF SNOW IS POSSIBLE NORTH OF THE LINE FROM ARNETT TO
FREEDOM. AREAS TO THE SOUTH ARE EXPECTED TO RECEIVE LESS.


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.

[jn1780]

You mean travelers advisory right? lol Just kidding of course.

[venture]

You mean travelers advisory right? lol Just kidding of course.

Oooooo.... LOL

[bluedogok]

We are getting about a foot of snow here in Aurora today.