General Weather Discussion - April 2014

[venture]

NAM has slowed some since yesterday's run. Based on that, outlined (in red) area below is the area with the risk of severe weather tomorrow. It looks like there is still a chance anything south of Highway 9 will be suppressed, but we'll see how things evolve tomorrow.



12Z GFS keeps wabbling and is a little faster than NAM still. It is further north with the precip though, keep it north of Guthrie/Stillwater and slowly spreading further south as it gets well east of the Metro.

This is going to be one of those last minute calls based on exact placement of the boundaries tomorrow morning.

[PennyQuilts]

NAM has slowed some since yesterday's run. Based on that, outlined area below is the area with the risk of severe weather tomorrow. It looks like there is still a chance anything south of Highway 9 will be suppressed, but we'll see how things evolve tomorrow.



12Z GFS keeps wabbling and is a little faster than NAM still. It is further north with the precip though, keep it north of Guthrie/Stillwater and slowly spreading further south as it gets well east of the Metro.

This is going to be one of those last minute calls based on exact placement of the boundaries tomorrow morning.

When you say outlined, I assume you mean the red? Hmm. I was going to go up to Edmond tomorrow afternoon but I think I will put it off until next week.

[venture]

Yes sorry...I fixed it.

[LocoAko]

Yes sorry...I fixed it.

Are those 850mb winds? I see two sets of barbs. Cool graphics though.

[venture]

Are those 850mb winds? I see two sets of barbs. Cool graphics though.

I really need to label better. Sorry surface winds. Then CAPE is outlined but not shaded in. The shaded in areas are surface dewpoint.

[venture]

Updated Day 2 shrinks the MDT risk area quite a bit.

...S-CNTRL CONUS...
12Z/SAT RAOBS IN THE WRN GULF COAST STATES SAMPLED A PRONOUNCED EML
WITH A CAP AROUND 850 MB AND MEAN MIXING RATIOS OF 10-13 G/KG.
ANOTHER DAY OF AIR MASS MODIFICATION WILL MAINTAIN A PLUME OF LOWER
TO MIDDLE 60S SURFACE DEW POINTS TO THE OZARK PLATEAU AND LOWER MS
VALLEY. ABUNDANT MID/HIGH-LEVEL CLOUD COVERAGE OVER THE SOUTHWEST
AND NRN MEXICO DOWNSTREAM OF THE SRN CA SHORTWAVE TROUGH SHOULD
OVERSPREAD THE ARKLATEX TO LOWER MS VALLEY WITH ATTENDANT WEAKENING
OF UPPER-LEVEL LAPSE RATES. IT IS POSSIBLE THAT HIGHLY ELEVATED
CONVECTION ABOVE THE LOW-LEVEL CAP MAY DEVELOP LATE D1 INTO EARLY D2
ACROSS PARTS OF CNTRL TX. THE 00Z ECMWF/12Z GFS SUGGEST THIS
ACTIVITY WOULD PERSIST THROUGH THE PERIOD AND MAY STRENGTHEN WITH
DIURNAL HEATING...POTENTIALLY YIELDING PRE-FRONTAL/DRYLINE SEVERE
STORMS FROM E TX TO THE LOWER MS VALLEY.

THE MORE CONSISTENT SIGNAL FOR SEVERE STORMS REMAINS ON SUN
AFTERNOON INVOF THE TRIPLE-POINT. STRONG LOW-LEVEL CONVERGENCE AND
DIURNAL HEATING SHOULD RESULT IN SCATTERED STORMS FORMING AROUND
MIDDAY NEAR/NE OF THE TRIPLE POINT ACROSS PARTS OF CNTRL/SE KS.
GIVEN ORIENTATION OF THE FRONT HERE ROUGHLY PARALLELING THE MEAN
WIND ALONG WITH THE UNDERCUTTING NATURE OF THE BOUNDARY...CONVECTION
SHOULD QUICKLY GROW UPSCALE WITH THE PRIMARY RISKS BEING SEVERE
HAIL/WIND.

FARTHER S FROM CNTRL OK TO N-CNTRL TX...INITIATION ALONG THE DRYLINE
SHOULD HOLD OFF UNTIL MID TO LATE AFTERNOON AS SURFACE TEMPERATURES
APPROACH 90 DEG F ACROSS SW OK/NW TX. MLCAPE NEAR 2500 J/KG...STEEP
MID-LEVEL LAPSE RATES AND 30-40 KT EFFECTIVE SHEAR WILL SUPPORT THE
POSSIBILITY OF INITIAL SUPERCELLS CAPABLE OF VERY LARGE HAIL AND A
FEW TORNADOES. THIS ACTIVITY SHOULD GROW UPSCALE SUN EVENING AND
POSSIBLY MERGE WITH THE NRN MCS EVOLVING ACROSS THE OZARK
PLATEAU...WITH ATTENDANT SEVERE RISK SHIFTING E/SEWD OVER THE
MID-SOUTH SUN NIGHT.

Probabilities
Brown = 5%, Yellow = 15%, Red = 30%, Purple = 45% -- White = Hatched 15% significant threat area

Moderate Risk is also contained in the Purple area and the Slight risk is the areas in the yellow area.

[venture]

Protect the plants if you already put any out.

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
131 PM CDT SAT APR 12 2014

OKZ004>032-034-035-038>043-046>048-130245-
/O.NEW.KOUN.FZ.A.0001.140415T0800Z-140415T1400Z/
HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD-
NOBLE-ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE-
BECKHAM-WA****A-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-
CLEVELAND-POTTAWATOMIE-SEMINOLE-HUGHES-GREER-KIOWA-COMANCHE-
STEPHENS-GARVIN-MURRAY-PONTOTOC-COAL-CARTER-JOHNSTON-ATOKA-
INCLUDING THE CITIES OF...BUFFALO...ALVA...CHEROKEE...MEDFORD...
PONCA CITY...ARNETT...WOODWARD...FAIRVIEW...ENID...PERRY ...
CHEYENNE...TALOGA...WEATHERFORD...CLINTON...WATONG A...
KINGFISHER...GUTHRIE...STILLWATER...ELK CITY...SAYRE...CORDELL...
ANADARKO...YUKON...EL RENO...MUSTANG...OKLAHOMA CITY...CHANDLER...
CHICKASHA...PURCELL...NORMAN...MOORE...SHAWNEE...S EMINOLE...
HOLDENVILLE...MANGUM...HOBART...LAWTON...DUNCAN... PAULS VALLEY...
SULPHUR...ADA...COALGATE...ARDMORE...TISHOMINGO... ATOKA
131 PM CDT SAT APR 12 2014

...FREEZE WATCH IS IN EFFECT EARLY TUESDAY...

* MINIMUM TEMPERATURE: 27 TO 32 DEGREES F.

* IMPACTS: TENDER VEGETATION WOULD BE AFFECTED DURING THE EXPECTED
2 TO 6 HOURS BELOW FREEZING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THINK ABOUT HOW YOU WILL PROTECT SENSITIVE PLANTS FROM THE COLD.

[venture]

Reiterating the theme for tomorrow - it all depends where the boundaries end up.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
201 PM CDT SAT APR 12 2014

.DISCUSSION...
EXTREMELY HOT AND DRY CONDITIONS IN WESTERN OKLAHOMA ALONG WITH
WINDS ABOUT 20 MPH WILL CONTINUE TO JUSTIFY THE RED FLAG WARNING
INTO THE EVENING TODAY. THE COLD FRONT WILL MOVE INTO NORTHWEST
OKLAHOMA BY SUNRISE SUNDAY. THE GFS AND NAM DIFFER SLIGHTLY IN
TIMING, BUT THEY BOTH PUSH THE DRYLINE THROUGH WEST CENTRAL AND
SOUTHWEST OKLAHOMA SUNDAY MORNING, WITH THE FRONT RACING SOUTH. BY
NOON THE DRYLINE MAY BE NEAR AN EL RENO TO WALTERS LINE - THIS
TAKING THE AVERAGE OF POSITIONS BETWEEN THESE 2 MODELS. THE
SOUTHWEST AND POSSIBLY CENTRAL OKLAHOMA WILL BE LEFT OUT OF
PRECIPITATION CHANCES; HOWEVER, RAIN AND THUNDERSTORMS BECOME
LIKELY QUICKLY TOWARDS THE NORTH OF OKLAHOMA CITY. THE WINDOW IS
BASICALLY SUNDAY AFTERNOON AS THE FRONT WILL BE MOVING FAST. THE
BIG STORY WILL BE THE GUSTY NORTH WINDS (APPROACHING WIND
ADVISORY) AND THE COLD AIR. TEMPERATURES SUNDAY AFTERNOON WILL
RANGE FROM THE 90S IN SOUTHWEST OKLAHOMA TO THE 60S IN THE
NORTHWEST. TEMPERATURES WILL CONTINUE TO DROP QUICKLY INTO THE 30S
AND LOWER 40 EVERYWHERE BY MONDAY MORNING. A FREEZE WATCH IS
EFFECTIVE EARLY TUESDAY OF MOST OF CENTRAL AND WESTERN OKLAHOMA
WHERE TEMPERATURES ARE EXPECTED TO RANGE THROUGH THE 20S AND LOWER
30S.

[SoonerDave]

90's one day, mid-30's the next....lived in Oklahoma (nearly) all my life, lots of seasons, but the Jekyll-and-Hyde weather never ceases to amaze...

[venture]

Some CU going up along the dryline in NW OK. Cap is pretty strong today, but they might be able to bust one through out west. If any make it through large hail is the main threat.

[Bunty]

It's a good thing fire danger levels aren't well up there across much of the state. Today has been one of April's windiest days.

[Bunty]

For those who may not know, downtown Oklahoma City finally has its own wundergroud web page. It features rapid fire data and a stunning webcam view of downtown. What more could you ask for?! It's at: Weather History for Weather Station KOKOKLAH72 | Weather Underground

[venture]

It appears the dryline is about to go in KS and possible NW OK. CU is increasing rapidly up there.

[Plutonic Panda]

protect the plants if you already put any out.

Urgent - weather message
national weather service norman ok
131 pm cdt sat apr 12 2014

okz004>032-034-035-038>043-046>048-130245-
/o.new.koun.fz.a.0001.140415t0800z-140415t1400z/
harper-woods-alfalfa-grant-kay-ellis-woodward-major-garfield-
noble-roger mills-dewey-custer-blaine-kingfisher-logan-payne-
beckham-wa****a-caddo-canadian-oklahoma-lincoln-grady-mcclain-
cleveland-pottawatomie-seminole-hughes-greer-kiowa-comanche-
stephens-garvin-murray-pontotoc-coal-carter-johnston-atoka-
including the cities of...buffalo...alva...cherokee...medford...
Ponca city...arnett...woodward...fairview...enid...perry ...
Cheyenne...taloga...weatherford...clinton...watong a...
Kingfisher...guthrie...stillwater...elk city...sayre...cordell...
Anadarko...yukon...el reno...mustang...oklahoma city...chandler...
Chickasha...purcell...norman...moore...shawnee...s eminole...
Holdenville...mangum...hobart...lawton...duncan... pauls valley...
Sulphur...ada...coalgate...ardmore...tishomingo... atoka
131 pm cdt sat apr 12 2014

...freeze watch is in effect early tuesday...

* minimum temperature: 27 to 32 degrees f.

* impacts: Tender vegetation would be affected during the expected
2 to 6 hours below freezing.

Precautionary/preparedness actions...

Think about how you will protect sensitive plants from the cold.

)(&(*^*$^%#^%#%(*&(*^&*$^%#%^$^&$#%$#%$# words i am not allowed to say on here!!!!!!

[venture]

New Day 1 should be out soon. 00Z NAM puts the Metro in play for severe weather tomorrow. 00Z GFS pushes it to the NE. New Euro will be out in an hour or so.

Chat room is up and going with the new platform I'm trying now. Twitter feeds are pulled out of the chat directly. Tested the new layout on an 8" tablet and it fit pretty well. Will try to have a mobile phone version done by tomorrow.

[venture]

New Moderate Risk area is in Yellow, area to the east of the green line is in the slight risk.

[venture]

Day 1 Text

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT SUN APR 13 2014

VALID 131200Z - 141200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF OK AND KS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL
PLAINS...SRN PLAINS...OZARKS...ARKLATEX AND LOWER TO MID MS
VALLEY...

...NRN OK/SE KS/OZARKS/MID MS VALLEY...
AN UPPER-LEVEL TROUGH OVER THE SRN ROCKIES THIS MORNING WILL MOVE
EWD INTO THE SRN AND CNTRL PLAINS BY THIS AFTERNOON. AT THE SFC...A
COLD FRONT WILL ADVANCE QUICKLY SEWD ACROSS ECNTRL KS AND NCNTRL OK
BY EARLY AFTERNOON. THUNDERSTORMS APPEAR LIKELY TO INITIATE BY MID
AFTERNOON ALONG THE FRONT...FIRST IN ERN KS AND THEN EXPANDING SSWWD
ALONG THE BOUNDARY INTO NCNTRL OK. THIS CONVECTION SHOULD CONTINUE
INTO THE EARLY TO MID EVENING AS THE FRONT MOVES ACROSS THE OZARKS
AND OUACHITA MTNS OF ERN OK. MODEL CONSENSUS AGREES WITH THIS
SCENARIO...DEVELOPING NUMEROUS STORMS ALONG THE BOUNDARY WITH A
POSSIBILITY OF MCS FORMATION DURING THE EVENING.

NAM FORECAST SOUNDINGS NEAR WICHITA KS SWD TO OKLAHOMA CITY AT 21Z
SHOW SFC DEWPOINTS IN THE LOWER 60S F WITH MLCAPE OF 1500 TO 2000
J/KG. IN ADDITION...0-6 KM SHEAR OF 30 TO 40 KT IS FORECAST WITH 850
TO 500 MB LAPSE RATES APPROACHING 8.5 C/KM. THIS ENVIRONMENT SHOULD
BE FAVORABLE FOR LARGE HAIL AS SUPERCELLS ORGANIZE ALONG THE COLD
FRONT LATE THIS AFTERNOON. THE LARGE HAIL THREAT SHOULD BE GREATEST
ACROSS THE MODERATE RISK AREA WHERE CONFIDENCE IS SUBSTANTIAL THAT
NUMEROUS SEVERE THUNDERSTORMS WILL DEVELOP IN A MODERATELY UNSTABLE
AIRMASS. ALTHOUGH STORM COVERAGE MAY DECREASE WITH SWD EXTENT...A
POTENTIAL FOR HAILSTONES GREATER THAN 2 INCHES IN DIAMETER SHOULD
EXIST WITH SUPERCELLS THAT DEVELOP ANYWHERE TO THE EAST OF THE
DRYLINE. A WIND DAMAGE THREAT SHOULD ALSO DEVELOP LATE THIS
AFTERNOON.

FURTHER TO THE EAST...ISOLATED TO SCATTERED THUNDERSTORMS MAY
INITIATE ACROSS THE OZARKS AND OUACHITA MTNS LATE THIS AFTERNOON.
FORECAST SOUNDINGS AT SPRINGFIELD MO AND LITTLE ROCK AR SHOW SBCAPE
VALUES OF 750 TO 1000 J/KG WITH 0-6 KM SHEAR OF 40 TO 50 KT. ANY
STORM THAT CAN INITIATE IN THE STRONGER INSTABILITY...COULD HAVE A
POTENTIAL FOR WIND DAMAGE AND LARGE HAIL. THE SEVERE THREAT SHOULD
INCREASE AS MORE WIDESPREAD FRONTAL CONVECTION MOVES INTO THE REGION
FROM THE WEST THIS EVENING.

...SRN OK/NORTH TX/ARKLATEX/LOWER MS VALLEY...
AN UPPER-LEVEL TROUGH AND ASSOCIATED 60 TO 75 KT MID-LEVEL JET WILL
MOVE ACROSS THE SRN PLAINS TODAY. AT THE SFC...A DRYLINE WILL BE IN
PLACE FROM NEAR OKLAHOMA CITY EXTENDING SWD INTO THE TX HILL
COUNTRY. ALTHOUGH THE CAP WILL WEAKEN QUICKLY ALONG THE DRYLINE BY
MIDDAY...THUNDERSTORMS ARE NOT FORECAST TO INITIATE UNTIL LATE THIS
AFTERNOON WHEN LOW-LEVEL CONVERGENCE SHOULD BECOME ENHANCED. THE
CURRENT THINKING IS THAT SEVERAL WIDELY SPACED THUNDERSTORMS SHOULD
INITIATE AND MOVE EWD ACROSS SRN OK AND NORTH TX FROM LATE THIS
AFTERNOON INTO EARLY THIS EVENING. THESE STORMS COULD DEVELOP INTO
SMALL CLUSTERS...MOVING EWD INTO THE ARKLATEX BY LATE EVENING.

FORECAST SOUNDINGS AT ARDMORE OK AND DALLAS TX AT 00Z/MON SHOW
MLCAPE OF 2500 J/KG WITH 0-6 KM SHEAR OF 50 KT. THIS COMBINED WITH
850 TO 500 MB LAPSE RATES ABOVE 8.0 C/KM SHOULD BE FAVORABLE FOR
SUPERCELLS WITH LARGE HAIL. HAILSTONES OF GREATER THAN 2 INCHES IN
DIAMETER MAY OCCUR WITH ANY SUPERCELL THAT CAN BECOME DOMINANT. IN
ADDITION...FORECAST SOUNDINGS SHOW LOOPED HODOGRAPHS WITH STRONGLY
VEERING WINDS WITH INCREASING HEIGHT FROM THE SFC TO 700 MB. THIS
WILL RESULT IN 0-3 KM STORM RELATIVE HELICITIES NEAR 400 M2/S2. THIS
ENVIRONMENT SHOULD SUPPORT A TORNADO THREAT WITH AN ISOLATED STRONG
TORNADO POSSIBLE. ISOLATED WIND DAMAGE MAY ALSO OCCUR.

..BROYLES/ROGERS.. 04/13/2014

[venture]

[venture]

To make the forecast nice and complicated tomorrow...here are some items from the 4Z HRRR that runs through 2PM.

Shield of light/moderate rain developing next few hours over TX moving north. Rain will move through the metro between 6 and 9AM.

By 11AM looks like initiation over NE KS that will fill down near the OK border by 2PM. HRRR does limit instability quite a bit and moves most of it into NE OK by early afternoon. It wants to have the dryline through here by Noon.

In contrast, the new 00Z Euro has the dryline moving through around 3-5PM in the afternoon. It also has instability up over 2000 j/kg for portions of the I-35 corridor. Euro initializes the dryline along I-44 by 1PM and moves it into the metro by 3PM.

Looks like an "early" show, so we'll take a look at things here in a few hours.

[bchris02]

So is this looking like it may be a Tulsa event more than an OKC one? If I have plans at 7:30 tonight, should this be over by then?

[PennyQuilts]

Tulsa plans? It doesn't look like "it" will be over but I suppose it depends in what "it" is and your tolerance for rough weather. Hail doesn't bother me if I'm home but I rescheduled my Afternoon Edmond trip because I didn't want to be out in it. If if was something big, like a wedding, I would have gone as things sit, right now. That's just me.

[venture]

Short range models and the more traditional models are in conflict right now on where storms initiate.

12Z NAM


12Z HRRR

[venture]

MOD risk is gone per SPC, here is the specific outlook for Oklahoma...

...ERN KS TO CENTRAL/ERN OK AND AR THIS AFTERNOON INTO TONIGHT...
THE INITIAL SRN STREAM SHORTWAVE TROUGH OVER THE SRN HIGH PLAINS
WILL EJECT ENEWD OVER N TX/OK/KS TODAY...REACHING MO/AR BY EARLY
TONIGHT AS AN UPSTREAM WAVE DIGS SEWD TO THE FOUR CORNERS. AT THE
SURFACE...THE REMNANTS OF A LEE CYCLONE IN SW KS THIS MORNING WILL
WEAKEN DURING THE DAY AND MOVE NEWD TO NW MO BY MID AFTERNOON...AND
CONTINUE ACROSS NRN IL TO LOWER MI OVERNIGHT. IN THE WAKE OF THE
LOW...A COLD FRONT WILL ACCELERATE SEWD ACROSS KS INTO NRN AND WRN
OK THROUGH THE AFTERNOON. WIDESPREAD CLOUDS WILL DISRUPT SURFACE
HEATING AND LAPSE RATES ALOFT...ASIDE FROM A NARROW CORRIDOR ALONG
THE COLD FRONT BY EARLY-MID AFTERNOON. BOUNDARY LAYER DEWPOINTS IN
THE LOWER 60S ARE EXPECTED BENEATH LINGERING STEEP MIDLEVEL LAPSE
RATES...WITH MLCAPE VALUES EXPECTED TO REACH 1500-2000 J/KG.

THE STRONGEST LOW-LEVEL ASCENT WILL BE ALONG THE COLD FRONT TO THE
NE OF THE DRYLINE-COLD FRONT TRIPLE POINT...WHICH WILL COINCIDE WITH
RATHER MODEST EFFECTIVE BULK SHEAR AND DEEP-LAYER FLOW/SHEAR VECTORS
LARGELY PARALLEL TO THE FRONT. THUS...ANY SUPERCELL STRUCTURES WILL
TEND TO BE RATHER SHORT-LIVED WELL NE OF THE TRIPLE POINT
/ESPECIALLY IN KS/ AND STORMS WILL LIKELY EVOLVE INTO A LINE ALONG
THE COLD FRONT. THE LINE OF STORMS WILL PERSIST INTO TONIGHT WITH A
RISK FOR LARGE HAIL AND DAMAGING GUSTS AS CONVECTION SPREADS
EWD/SEWD FROM SE KS/ERN OK TO AR. MEANWHILE ...VERTICAL SHEAR WILL
BE STRONGER IN PROXIMITY TO THE TRIPLE POINT...WHERE THE POTENTIAL
EXISTS FOR AN ANCHOR SUPERCELL CAPABLE OF PRODUCING VERY LARGE HAIL
AND A TORNADO OR TWO THIS AFTERNOON/EVENING.

[Anonymous.]

Nice clearing ahead of dryline. Beginning to see dryline bulge out in extreme SW OK.

[venture]

CU development ahead of the dryline and cold front back to the NW is going really well now.