General Weather Discussion - February 2014

[venture]

February 2014 has ended. Discussion continues in the March 2014 Thread: http://www.okctalk.com/showwiki.php?title=Island:36945

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Snowfall Forecast Models

GEM Snowfall	12Z/0Z NAM Snowfall	WRF Snowfall	12Z / 0Z GFS Snowfall

Freezing Rain Forecast Models

GEM Freezing Rain	12Z/0Z NAM Freezing Rain	12Z / 0Z GFS Freezing Rain

Additional information is always available via: http://www.weatherspotlight.com/ Including the side-by-side model comparisons per run time.

[venture]

ECMWF Overview...

Sunday: No major changes in the Euro forecast. Main area of accumulating precip appears to be south of I-40. Looks like a dusting/less than an inch north of I-40, about 1-2" south to a Lawton-Ada line, then maybe 2-4" just south of there in spots.

Tuesday: Looks like NW OK and NC OK will get the heaviest snow. As Anon has said, Central may get dry slotted some or at least amounts kept well in check. Probably still looking at 1-3" for the Metro, lighter south. Area of 4-6" up between Woodward to Enid.

Thursday: Light snow over much of SW, C, and NE OK. About an inch.

Friday: Light/Mdt Snow. Another 1-3" for the metro.

[Easy180]

That looks doable. The car washes will rake in the dough the week after next

[venture]

Winter Storm Watch for Southern OK tonight through tomorrow.

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
418 AM CST SAT FEB 1 2014


OKZ032-036>048-050>052-TXZ083>090-011815-
/O.NEW.KOUN.WS.A.0001.140202T0000Z-140203T0000Z/
HUGHES-JACKSON-TILLMAN-COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-
COAL-COTTON-JEFFERSON-CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-
HARDEMAN-FOARD-WILBARGER-WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
INCLUDING THE CITIES OF...HOLDENVILLE...ALTUS...FREDERICK...
LAWTON...DUNCAN...PAULS VALLEY...SULPHUR...ADA...COALGATE...
WALTERS...WAURIKA...ARDMORE...TISHOMINGO...ATOKA.. .MARIETTA...
MADILL...DURANT...QUANAH...CHILLICOTHE...CROWELL.. .VERNON...
WICHITA FALLS...MUNDAY...KNOX CITY...SEYMOUR...ARCHER CITY...
HOLLIDAY...LAKESIDE CITY...HENRIETTA
418 AM CST SAT FEB 1 2014


...WINTER STORM WATCH IN EFFECT FROM THIS EVENING THROUGH SUNDAY
AFTERNOON...


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A WINTER STORM
WATCH...WHICH IS IN EFFECT FROM THIS EVENING THROUGH SUNDAY
AFTERNOON FOR PARTS OF SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS.


* TIMING: TONIGHT INTO SUNDAY...WITH THE HEAVIEST PRECIPITATION
BETWEEN 3 AM AND 3 PM.


* MAIN IMPACT: A MIX OF SNOW...SLEET...FREEZING RAIN...AND RAIN
WILL DEVELOP TONIGHT...THEN SWITCH OVER TO SNOW WEST TO EAST.
PRECIPITATION WILL END WEST TO EAST ON SUNDAY. TOTAL SNOW AND
SLEET ACCUMULATIONS OF 2 TO 5 INCHES WITH LOCALLY HEAVIER
AMOUNTS ARE LIKELY. TOTAL ICE ACCUMULATIONS UP TO 0.25 INCH ARE
ALSO LIKELY MAINLY SOUTHEAST OF A WICHITA FALLS TO ADA LINE.


* OTHER IMPACTS: SNOW...SLEET...AND ICE ACCUMULATIONS WILL MAKE
TRAVEL SLICK AND HAZARDOUS TONIGHT INTO SUNDAY. MOTORISTS
SHOULD USE EXTRA CAUTION.

[Anonymous.]

Latest GFS runs bringing Sunday's system further north. Or at least developing a decent snow band somewhere over SW to C OK. Including the OKC area.

Latest NAM also has north trend.



I will say that Tuesday is looking interesting on GFS. Trying to close off the low more and possibly let more snow in the picture for main body of OK instead of massive dry slot. Will watch the trends.

[venture]

Winter Storm Warnings are up now for the southern counties...

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
126 PM CST SAT FEB 1 2014


OKZ032-036>048-050>052-TXZ083>090-020330-
/O.UPG.KOUN.WS.A.0001.140202T0000Z-140203T0000Z/
/O.NEW.KOUN.WS.W.0001.140202T0300Z-140203T0000Z/
HUGHES-JACKSON-TILLMAN-COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-
COAL-COTTON-JEFFERSON-CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-
HARDEMAN-FOARD-WILBARGER-WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
INCLUDING THE CITIES OF...HOLDENVILLE...ALTUS...FREDERICK...
LAWTON...DUNCAN...PAULS VALLEY...SULPHUR...ADA...COALGATE...
WALTERS...WAURIKA...ARDMORE...TISHOMINGO...ATOKA.. .MARIETTA...
MADILL...DURANT...QUANAH...CHILLICOTHE...CROWELL.. .VERNON...
WICHITA FALLS...MUNDAY...KNOX CITY...SEYMOUR...ARCHER CITY...
HOLLIDAY...LAKESIDE CITY...HENRIETTA
126 PM CST SAT FEB 1 2014


...WINTER STORM WARNING IN EFFECT FROM 9 PM THIS EVENING TO 6 PM
CST SUNDAY...


THE WINTER STORM WATCH IS NO LONGER IN EFFECT.


* TIMING: TONIGHT AND SUNDAY...WITH THE HEAVIEST PRECIPITATION
BETWEEN 3 AM AND 3 PM.


* MAIN IMPACT: A MIX OF SNOW...SLEET...FREEZING RAIN...AND RAIN
WILL DEVELOP TONIGHT...THEN SWITCH OVER TO SNOW WEST TO EAST.
PRECIPITATION WILL END WEST TO EAST ON SUNDAY. TOTAL SNOW AND
SLEET ACCUMULATIONS OF 2 TO 5 INCHES WITH LOCALLY HEAVIER
AMOUNTS ARE LIKELY. TOTAL ICE ACCUMULATIONS UP TO 0.25 INCH ARE
ALSO LIKELY MAINLY SOUTHEAST OF A WICHITA FALLS TO ADA LINE. ICE
ACCUMULATIONS AROUND DURANT AND ATOKA MAY EXCEED 0.25 INCH
SUNDAY AND NECESSITATE A FURTHER WARNING.


* OTHER IMPACTS: SNOW...SLEET...AND ICE ACCUMULATIONS WILL MAKE
TRAVEL SLICK AND HAZARDOUS TONIGHT INTO SUNDAY. MOTORISTS
SHOULD USE EXTRA CAUTION.


PRECAUTIONARY/PREPAREDNESS ACTIONS...


KEEP UP WITH THE LATEST WEATHER INFORMATION...ESPECIALLY IF YOU
PLAN TO TRAVEL.

[s00nr1]

18Z NAM and HRRR now both pushing heavy snowfall rates into Central OK tomorrow. Would not be surprised to see OUN put out some advisory text shortly for those counties.

[venture]

So the 12PM-3PM segment is the one that has me a little concern now...

All snow, or should be...with a basic 10:1 ratio...

[venture]

The image is also a pretty good indication of how narrow the snow band will probably be tomorrow. Also how much the effects on the Metro will vary widely from end to end. From that image along, that is an inch or two from Yukon to Edmond and nearly 8 inches in Norman.

[blangtang]

18Z NAM and HRRR now both pushing heavy snowfall rates into Central OK tomorrow. Would not be surprised to see OUN put out some advisory text shortly for those counties.

what is the color legend saying ? 1/10 of an inch? confused

[venture]

what is the color legend saying ? 1/10 of an inch? confused

My bad. The legend is liquid precip...so take the number and multiple it by 10 to get a basic snowfall amount.

[Easy180]

Let's hope the 6-8 stays just south of Norman. Cool with 2-4 as long as it's the white stuff

[s00nr1]

Well there's certainly a decent jet stream up there. Just went from DFW to Atlanta in 1 hour.

[Anonymous.]

Classic. Models say one thing for 4 days straight, 16 hours away from event and they all change.

[venture]

18Z GFS not completely in line with NAM. 1-2" for Metro area by 6AM, 6AM to 9AM another 1-3" South Metro, <1" North Metro, then lighter snow with maybe another 1" for the south Metro through 3PM.

So recap of the various model runs for the Metro max snowfall predictions as of right now, with the understand higher is going to be Norman area and south.
06Z GFS: 1-4" (highest on this run was actually W Metro)
12Z GFS: 2-3"
18Z GFS: 3-6"
12Z NAM: 1-2"
18Z NAM: 5-8", up to 10" further SW.
12Z GEM: 2-4"
12Z WRF: ~1"
00Z ECMWF: 1-2"
12Z ECMWF: 2-4"

The afternoon runs are in bold.

[venture]

Oh...and Braums is running out of milk on the east side here in Norman. So the run is on.

[venture]

Winter Wx Advisory up for counties north of the Warning area...

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
507 PM CST SAT FEB 1 2014


OKZ021>031-033>035-020715-
/O.NEW.KOUN.WW.Y.0004.140202T0300Z-140203T0000Z/
BECKHAM-WA****A-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-
CLEVELAND-POTTAWATOMIE-SEMINOLE-HARMON-GREER-KIOWA-
INCLUDING THE CITIES OF...ELK CITY...SAYRE...CORDELL...ANADARKO...
YUKON...EL RENO...MUSTANG...OKLAHOMA CITY...CHANDLER...
CHICKASHA...PURCELL...NORMAN...MOORE...SHAWNEE...S EMINOLE...
HOLLIS...MANGUM...HOBART
507 PM CST SAT FEB 1 2014


...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
6 PM CST SUNDAY...


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND SLEET...WHICH IS IN EFFECT FROM
9 PM THIS EVENING TO 6 PM CST SUNDAY.


* TIMING: SNOW AND SLEET ARE EXPECTED TO START OVER FAR WEST
CENTRAL OKLAHOMA TOWARD MIDNIGHT...THEN SPREAD INTO CENTRAL
OKLAHOMA AROUND SUNRISE SUNDAY. THE HEAVIEST PRECIPITATION IS
EXPECTED TO FALL BETWEEN 3 AM AND 3 PM.


* MAIN IMPACT: SNOW AND SLEET ACCUMULATIONS OF 1 TO 3 INCHES WILL
BE POSSIBLE ACROSS WEST-CENTRAL INTO CENTRAL OKLAHOMA...MAINLY
NEAR AND SOUTH OF INTERSTATE-40.


PRECAUTIONARY/PREPAREDNESS ACTIONS...


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

[LocoAko]

WWA now up for the metro for 1-3".

Latest HRRR is pretty intense, with a very narrow band exceeding 12" in SW OK already by 5AM. Hm.

[Hollywood]

Working this evening, what time should we expect any falling precipitation to begin?

[Mel]

Oh...and Braums is running out of milk on the east side here in Norman. So the run is on.

Got the bread covered but need milk. Now.

[venture]

Working this evening, what time should we expect any falling precipitation to begin?

For the metro...probably closer to 1-3AM.

[Hollywood]

For the metro...probably closer to 1-3AM.

Just as I get off duty. Works for me.

[Anonymous.]

Okay the bottomline about what is going to happen tonight.

Someone is going to get hit with 1-2"+ per hour snowfall rates underneath a band that we call a deformation band or zone. This occurs when a storm system rides up along a boundary and on the cold side (the northwest side) of the comma head is going to usually have an intense, narrow shield of precipitation. In this case, it will be especially narrow due to the size of the system and the nature of it shoving off to the ENE and getting ripped through the jet stream once it passes across N TX.

So before the low actually drifts into the jetstream aloft and gets ripped to shreds and flies NE across the country, it will have time to anchor down and pull in moist air from the deep south and then this air will rise over this cold air in place here resulting in the above mentioned deformation zone.

This is difficult to forecast because the area of intense snow gradient will be relatively narrow. Radar trends late tonight will foreshadow everything.

The latest NAM runs are making me think this band may try to set up along 44 and just south. However, the northern trend is cooking right now.

[venture]

Bread and Milk!

[s00nr1]

Of course.... I leave OKC to attend a weather conference (AMS) in Atlanta and am going to miss this.