Oklahoma Weather Discussion - February/March 2013

[s00nr1]

This is some kind of sick joke:

[OKCisOK4me]

24 degrees Fahrenheit? It is factually recorded that the last freeze for OKC metro area is usually in early April so this doesn't surprise me.

[s00nr1]

Well, if we're going to be this PITA unseasonably cold, we might as well have some snow to go with it:

[OKCTalker]

"PITA unseasonably cold?" The high temps for the next five days are forecast to be in the mid-to-upper sixties!

[s00nr1]

OKCTalker: I'm not sure where you've been the last few weeks, but other than a short 3-day stretch temperatures have run well-below average for the month of March.

[OKCisOK4me]

Yes Gary did say we've had January average temps this month.

[Anonymous.]

Looks like sporadic rain chances Friday thru possibly Tuesday. Not a wash-out, but it appears to be some decent chances of waves/storms of precip.

[kelroy55]

I better get the back yard mowed tonight or tomorrow night.

[bchris02]

It looks like another arctic blast is in store for next week. Its looking like we will start April with highs in the 30s and lows in the low 20s/high 10s with rain/snow mix possible Monday into Tuesday. Typical January weather in April.

[Plutonic Panda]

It looks like another arctic blast is in store for next week. Its looking like we will start April with highs in the 30s and lows in the low 20s/high 10s with rain/snow mix possible Monday into Tuesday. Typical January weather in April.

This freakin sucks!!!!!!!!!!!

[venture]

Storm Prediction Center Mar 28, 2013 0730 UTC Day 3 Severe Thunderstorm Outlook

The new look SPC site is out and is pretty spiffy. With that, we are under a slight risk on Saturday for nearly everyone west of I-35.

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT THU MAR 28 2013

VALID 301200Z - 311200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF NWRN TX...WRN
OK INTO SWRN AND CNTRL KS...

...SYNOPSIS...

ERN U.S. UPPER TROUGH WILL UNDERGO AMPLIFICATION THIS PERIOD WITH AN
UPPER JET STREAK DROPPING SEWD THROUGH THE NRN PLAINS INTO THE UPPER
AND MID MS VALLEY REGIONS. THIS PROCESS WILL BE ASSOCIATED WITH SEWD
ACCELERATION OF A COLD FRONT THAT SHOULD EXTEND FROM MN SWWD THROUGH
WY EARLY SATURDAY...LIKELY STRETCHING FROM THE GREAT LAKES SWWD INTO
THE SRN HIGH PLAINS BY THE END OF THE PERIOD. WARM FRONT SHOULD LIFT
NEWD THROUGH THE TN AND OH VALLEYS AS SWLY FLOW STRENGTHENS IN THIS
REGION IN ASSOCIATION WITH A DEVELOPING CYCLONE.

...CNTRL KS THROUGH OK AND NWRN TX REGIONS...

CLUSTERS OF STORMS SHOULD BE ONGOING EARLY SATURDAY WITHIN A BROAD
ZONE OF WARM ADVECTION FROM PORTIONS OF THE SRN/CNTRL PLAINS INTO
THE LOWER-MID VALLEY REGIONS AND SHIFT EWD DURING THE DAY. IN WAKE
OF MORNING ACTIVITY...LOW-MID 50S DEWPOINTS WILL HAVE ADVECTED INTO
THE BROAD WARM SECTOR. STRONGER DIABATIC WARMING IS EXPECTED FROM
THE HIGH PLAINS OF TX AND OK INTO WRN/CNTRL KS...LIKELY BOOSTING
MLCAPE TO 1000-1500 J/KG. THE POTENTIAL WILL EXIST FOR STORMS TO
REDEVELOP DURING THE AFTERNOON...MOST LIKELY ALONG SEWD ADVANCING
COLD FRONT FROM KS SWWD INTO THE TX AND OK PANHANDLES. OTHER STORMS
MAY DEVELOP IN VICINITY OF DRYLINE OVER NWRN TX. THE ACTIVITY WILL
THEN SHIFT SEWD DURING THE EVENING. FLOW IN THE 0-3 KM LAYER IS
FORECAST TO REMAIN RATHER WEAK. THIS REGION WILL RESIDE JUST SOUTH
OF THE STRONGER FLOW ALOFT ASSOCIATED WITH THE AMPLIFYING NRN STREAM
TROUGH WITH EFFECTIVE SHEAR FROM 30-40 KT. THIS ENVIRONMENT MAY
BECOME SUFFICIENT FOR STORMS TO ORGANIZE WITH AT LEAST MARGINAL
SUPERCELL STRUCTURES POSSIBLE EARLY IN THE EVOLUTION. ISOLATED LARGE
HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN THREATS FROM LATE
AFTERNOON INTO THE EVENING.

..DIAL.. 03/28/2013

[venture]

12Z Model runs showing potential for severe weather is increase in the state as we close out the month. Models have some differences between them and a lot of this is dependent on pre-existing convection from the prior day. Going to go day by day.

Today
Nothing. Beautiful Spring day. Enjoy it. Now for later tonight isolated showers and storms are forecast to develop, really over anywhere in the state. Highest concentration will be to the east. NAM focuses coverage in NE OK, GFS is more broad and NSSL WRF has it pretty scattered all over - with most after dark. Things are unstable out there, you can feel the moisture returning with dews back into the 50s over much of the state. However, don't expect anything to get too rambunctious.

Friday
A few early showers/storms NE OK. Rain starts to develop in the afternoon over Central back into NW OK. Rain will expand back to the SW part of the state through the evening. NAM is more aggressive with precip, GFS is much lighter in amounts and coverage. For Central OK, things will be unstable early and then stabilize through the afternoon as the precip moves back to the west. We could see a couple stronger storms here with some small hail and gusty winds. Threat will shift pretty far west overnight and then return Saturday.

Saturday
This looks like the first bonafide severe weather day of the season. We'll have to see how this unfolds but it could be a good one. This day is already outlooked as a Slight Risk by SPC in their Day 3. Instability through the afternoon will be high across Central into Western OK. We are looking at a fairly widespread area of CAPE values from 2500 to 3500 j/kg from Lake Eufaula back to Lawton and then North. Right now it appears we'll see scattered supercells and line segments get going in the mid to late afternoon across Western OK. Things should then firm up to a solid line or organized segments of embedded supercells. Reaching most of the Metro area by 8-10PM. Forecast soundings are pretty significant for this early in the season. A lot of the parameters are lined up for a high end Slight Risk day, but there are also several limiting factors from calling this a Moderate Risk day. SRH values don't look exciting when the storms move in, but there will be some shear present. We are looking at surface winds coming out of the South with upper level winds from the WNW. General rule of thumb, if you want things turning, SE wind is best...but not needed. Storm motions look reasonable for this time of year - 300 @ 16 kts on average. Considering April is known for storms that just go flying by at 40-60 mph, I'll take some slow movers. So main thing here, if you have outdoor plans just stay weather aware come late afternoon into the overnight.

Sunday
Looks like some left over storms and a few new ones in the afternoon. Looking at mainly I-40 and south. Instability will be there, but this looks like a calmer day compared to Saturday. Nothing to worry about right now.

Looks like we'll then have a calm (severe weather wise) week ahead. GFS is still sticking with its snowfall Tuesday/Wednesday, but amounts look light overall. Maybe a quarter inch of precip those days, so if the snow does happen it'll only be a couple inches on relatively warm ground. So travel issues look like they'll be close to zero. Temps rebound and we are back into the 60s and 70s next weekend, with another chance of severe weather as a strong storm system pulls through. Shocker I know.

[OKCTalker]

OKCTalker: I'm not sure where you've been the last few weeks, but other than a short 3-day stretch temperatures have run well-below average for the month of March.

s00nr1 - I thought that you were talking about UPCOMING unseasonably cold weather, not that cold mess we'd already gone through.

[jn1780]

I hope it stays Spring after next week's cold snap. lol

[venture]

I hope it stays Spring after next week's cold snap. lol

Key part...stays Spring and not jump right into Summer. LOL

[Achilleslastand]

I hope it stays Spring after next week's cold snap. lol

You forgot the hope we have a VERY wet spring part hehe.

[kelroy55]

You forgot the hope we have a VERY wet spring part hehe.

Amen on that

[venture]

SPC has gone ahead and done a Slight Risk for today over Western Oklahoma.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1220 AM CDT FRI MAR 29 2013

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF ERN TX
PANHANDLE...FAR WRN OK...

...SYNOPSIS...
SYNOPTIC PATTERN WILL CHANGE LITTLE DURING THE PERIOD. IN THE
MEAN...A LOW AMPLITUDE TROUGH WILL PERSIST OVER THE ERN CONUS WITH
AN UPSTREAM RIDGE IN THE WEST. AT THE SURFACE...A LEE TROUGH/DRYLINE
WILL OSCILLATE ACROSS THE CNTRL/SRN HIGH PLAINS...WHILE A WEAK
QUASI-STATIONARY FRONT REMAINS ANCHORED ACROSS PARTS OF OK/AR.

...SRN/CNTRL PLAINS...
ISOLATED TO WIDELY SCATTERED TSTMS THIS AFTERNOON THROUGH TONIGHT
MAY PRODUCE SPORADIC REPORTS OF LARGE HAIL AND SEVERE WIND.
CONFIDENCE IS GENERALLY LOW IN DELINEATING CORRIDORS OF SLIGHT RISK
THREAT...EXCEPT INVOF ERN TX PANHANDLE.

MODEST GULF MOISTURE RETURN WILL CONTINUE IN THE WARM MOIST SECTOR
AHEAD OF THE HIGH PLAINS DRYLINE BENEATH A PRONOUNCED CAPPING
INVERSION /BASE OF THE EML/ SAMPLED IN THU EVENING RAOBS. EVEN WITH
DAYTIME MIXING...AN AXIS OF UPPER 40S TO MIDDLE 50S SURFACE DEW
POINTS SHOULD BE MAINTAINED ACROSS PARTS OF WRN OK/TX. DESPITE
NEAR-NEUTRAL MID-LEVEL HEIGHT CHANGE AND LIKELY ONLY WEAK
CONVERGENCE INVOF THE DRYLINE...A ZONE OF DEEP MIXING JUST BEHIND
THE DRYLINE MAY SUFFICIENTLY WEAKEN THE CAPPING INVERSION ALONG IT.
STRENGTH OF THE CAP WITH ERN EXTENT IN THE WARM/MOIST SECTOR
INCREASES UNCERTAINTY REGARDING DEGREE/SUSTAINABILITY OF STORM
COVERAGE. BEST CHANCE FOR MORE THAN JUST ISOLATED COVERAGE MAY EXIST
INVOF THE DRYLINE/STATIONARY FRONT INTERSECTION. MODERATE DEEP-LAYER
SHEAR ALONG WITH STEEP MID-LEVEL LAPSE RATES YIELDING MLCAPE OF
1000-1500 J/KG MAY SUPPORT A FEW SUPERCELLS PRODUCING LARGE HAIL AND
SEVERE WINDS. MODEST EVENING LLJ RESPONSE IN THE PLAINS MAY SUSTAIN
A COUPLE OF STRONG TO MARGINALLY SEVERE CLUSTERS TONIGHT.

..GRAMS.. 03/29/2013

[venture]

Slight Risk for Saturday has been expanded to cover much of the state except for NW OK.

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT FRI MAR 29 2013

VALID 301200Z - 311200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF OK...ERN
KS...AND NRN TX...

...SYNOPSIS...
A NWLY FLOW REGIME WILL EXIST FROM THE CNTRL STATES TO THE ATLANTIC
COAST AS A LARGE UPPER LOW DRIFTS SWD ACROSS S-CNTRL CANADA. AN
EMBEDDED SHORTWAVE TROUGH WILL TRAVEL SEWD ACROSS THE NRN PLAINS AND
UPPER MS VALLEY DURING THE DAY...REACHING THE OH VALLEY BY SUN
MORNING. A WEAK COLD FRONT WILL ACCOMPANY THIS TROUGH...EXTENDING
FROM WI INTO WRN OK BY 00Z. SLY FLOW AHEAD OF THIS FRONT WILL HELP
MAINTAIN MID 50S F BOUNDARY LAYER DEWPOINTS FROM ERN KS SWD INTO
TX...RESULTING IN A POTENTIALLY FAVORABLE ENVIRONMENT FOR SEVERE
HAIL AND WIND BY LATE IN THE DAY.

...OK...NRN TX...SERN KS...WRN AR...
A COMPLEX AND UNCERTAIN SEVERE STORM EVOLUTION IS ANTICIPATED ACROSS
THE SRN PLAINS ON SATURDAY...WITH A CONDITIONAL THREAT OF
POTENTIALLY DAMAGING WIND-DRIVEN HAIL OVER A LARGE AREA FROM SERN KS
INTO NRN TX.

SATURDAY MORNING...RAIN AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING
ACROSS ERN OK AND WRN AR...IN ASSOCIATION WITH A WEAK SHORTWAVE
TROUGH AND IN A ZONE OF WARM ADVECTION WITH WLY 850 MB FLOW. THIS
ACTIVITY IS NOT EXPECTED TO BE SEVERE...AS IT WILL BE ON THE ERN
FRINGE OF THE STEEPER DEEP TROPOSPHERIC LAPSE RATES.

DURING THE DAY...STRONG HEATING WILL OCCUR AHEAD OF THE COLD
FRONT...WITH WEAK CONVERGENCE WITHIN THE SURFACE TROUGH FROM ERN KS
INTO WRN OK AND INTO WRN TX. MODELS DISAGREE WITH DEGREE OF
HEATING...BUT THE NAM SUGGESTS VERY STEEP LOW LEVEL LAPSE RATES WILL
EXIST WITH LITTLE CAPPING AND DEVELOPS STORMS WITH THE SFC TROUGH BY
00Z. IF THIS OCCURS...SUPERCELLS AND SSEWD PROPAGATING CELL CLUSTERS
WOULD BE LIKELY CAPABLE OF LARGE HAIL AND DAMAGING WINDS. HODOGRAPHS
MAY JUST BE LONG ENOUGH FOR A FEW STORMS TO PRODUCE WIND DRIVEN
HAIL. STORM FORMATION COULD BE DELAYED UNTIL THE 00-03 TIME FRAME.
CELLS MAY EVENTUALLY AFFECT WRN AR AS WELL AS THE RED RIVER REGION.

THERE IS ALSO THE POTENTIAL FOR STORM COVERAGE TO BE SPARSE GIVEN
THE WEAK FORCING...AND IF SURFACE TEMPERATURES DO NOT GET WARM
ENOUGH TO TOTALLY ERODE CIN. MODEL CONSENSUS SUGGESTS THE HIGHEST
RELATIVE THREAT TO BE OVER SERN KS AND NERN OK LATE IN THE DAY INTO
THE EVENING.

..JEWELL.. 03/29/2013

[Anonymous.]

Thunderstorms developing just W of OKC and moving ESE currently. Hopefully we can get soaked under one.

[venture]

Slight Risk today updated to cover pretty much all of SW OK now.

...CENTRAL/SOUTHERN PLAINS...
WEAK CONVECTIVE DEVELOPMENT IS ONGOING ACROSS PARTS OF SOUTHEAST
KANSAS AND EASTERN OKLAHOMA INTO THE OZARK PLATEAU. THIS IS
ASSOCIATED WITH MOISTURE RETURN WITHIN A LOWER/MID TROPOSPHERIC WARM
ADVECTION REGIME...ABOVE A RESIDUAL COOL AND STABLE BOUNDARY
LAYER...ON THE NORTHEASTERN PERIPHERY OF MORE STRONGLY CAPPING
ELEVATED MIXED LAYER AIR WHICH HAS ADVECTED EAST OF THE SOUTHERN
ROCKIES. THIS ACTIVITY MAY PERSIST UNTIL WESTERLY 850 MB FLOW
ACROSS THE SOUTHERN PLAINS BEGINS TO BACK TO A MORE SOUTHERLY
COMPONENT TOWARD MID DAY...AHEAD OF THE APPROACHING SHORT WAVE
IMPULSE.

IN THE MEANTIME...STRONG SURFACE HEATING ACROSS THE SOUTHERN HIGH
PLAINS WILL CONTRIBUTE TO STEEPENING LOW-LEVEL LAPSE RATES...A
SHARPENING DRY LINE ACROSS THE TEXAS PANHANDLE AND SOUTH
PLAINS...AND A STRENGTHENING BAROCLINIC ZONE ACROSS THE TEXAS
PANHANDLE INTO THE RED RIVER VALLEY BY LATE THIS AFTERNOON. THESE
FEATURES...PARTICULARLY NEAR THEIR INTERSECTION ACROSS THE TEXAS
PANHANDLE/NORTHWEST TEXAS...SEEM LIKELY TO PROVIDE THE FOCUS FOR
STRONGEST CONVECTIVE DEVELOPMENT...IN THE PRESENCE OF MIXED LAYER
CAPE ON THE ORDER OF 1000-1500 J/KG.

GIVEN THE FAVORABLE THERMODYNAMIC ENVIRONMENT...VEERING OF WINDS
WITH HEIGHT BENEATH MODEST WESTERLY MID/UPPER FLOW SHOULD PROVIDE
SUFFICIENT SHEAR FOR SEVERE STORMS...INCLUDING SUPERCELLS...CAPABLE
OF PRODUCING LARGE HAIL AND LOCALLY DAMAGING WIND GUSTS. IT APPEARS
POSSIBLE THAT FORCING ASSOCIATED WITH THE MID-LEVEL IMPULSE COULD
CONTRIBUTE TO A CONSOLIDATING STORM CLUSTER ALONG THE FRONTAL ZONE
ACROSS PARTS OF SOUTHWESTERN OKLAHOMA AND NORTHWEST TEXAS DURING THE
EVENING HOURS...WITH PERHAPS A WINDOW OF OPPORTUNITY FOR MORE
WIDESPREAD STRONG/SEVERE GUSTS...BEFORE POTENTIAL DIMINISHES WITH
BOUNDARY LAYER COOLING.

[venture]

Incoming storms do have some radar indicated hail with them (red areas).

[venture]

So begins Spring...

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
948 AM CDT FRI MAR 29 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
SOUTHEASTERN CANADIAN COUNTY IN CENTRAL OKLAHOMA...
NORTHWESTERN CLEVELAND COUNTY IN CENTRAL OKLAHOMA...
EXTREME NORTHEASTERN GRADY COUNTY IN CENTRAL OKLAHOMA...
EXTREME NORTHWESTERN MCCLAIN COUNTY IN CENTRAL OKLAHOMA...
SOUTHWESTERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1030 AM CDT


* AT 947 AM CDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE
THUNDERSTORM PRODUCING QUARTER SIZE HAIL. THIS STORM WAS LOCATED 4
MILES WEST OF MUSTANG...MOVING EAST AT 35 MPH.


* LOCATIONS IMPACTED INCLUDE...
OKLAHOMA CITY...MIDWEST CITY...MOORE...DEL CITY...STELLA...
MUSTANG...LAKE THUNDERBIRD...STANLEY DRAPER LAKE...TINKER AIR
FORCE BASE AND VALLEY BROOK.

[Anonymous.]

The SVR warned cell moving into OKC has slight rotation, this will increase the hail sizes. Quarters were reported in Chickasha.

[Anonymous.]

Took a glacing blow as the storm lost steam. Just some quick rain.

Hopefully we get some more action tonight.