Topic: Plains Threat Today

[Farmtalk]

Anybody checked out today's slight risk area for severe weather? I know Ryan over in Hays is in the Slight zone. I think it's been a pretty quiet year overall other than May.

[cospringswx]

It has been unusually quiet since May. I sure could use the rain but not the severe WX.

[Farmtalk]

SPC is feeling pretty optimistic today about storm chances.

[Bunty]

It has been unusually quiet since May. I sure could use the rain but not the severe WX.

Same here, especially for September.  After getting bypassed from the heavy rains only .37 has fallen, so far, for September, the third rainiest month of the year here.   Average is 4.13".  But projected rainfall amount from the approaching front is under .50.

[BigOkie]

It has been unusually quiet since May. I sure could use the rain but not the severe WX.

Same here, especially for September.  After getting bypassed from the heavy rains only .37 has fallen, so far, for September, the third rainiest month of the year here.   Average is 4.13".  But projected rainfall amount from the approaching front is under .50.

Remember though...the second severe weather season typically starts for us in October.  It's never as threatening as April-June, but there are storms that occur.  Part of 'Indian summer' I guess.

[Bunty]

Slight risk today for roughly western 1/3rd of Oklahoma meaning hail, wind and tornadoes.  It will be interesting to see if a watch will have to be issued later.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 AM CDT FRI SEP 27 2013


VALID 271200Z - 281200Z


...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
ACROSS MUCH OF THE CENTRAL INTO SOUTHERN PLAINS...


...SYNOPSIS...
LITTLE CHANGE TO THE LARGE-SCALE MID/UPPER PATTERN IS EXPECTED
THROUGH THIS FORECAST PERIOD ACROSS THE EASTERN U.S...WITH WEAK
TROUGHING LINGERING EAST OF THE ATLANTIC COAST...AND A SHARP UPPER
RIDGE REMAINING PROMINENT NORTH OF A WESTERN GULF OF MEXICO
SUBTROPICAL HIGH CENTER THROUGH THE GREAT LAKES REGION.
HOWEVER...LARGE SCALE MID/UPPER TROUGHING OVER THE WESTERN STATES
APPEARS LIKELY TO BECOME LESS AMPLIFIED...AS A SIGNIFICANT EMBEDDED
SHORT WAVE IMPULSE SHIFTS NORTHEASTWARD OUT OF THE GREAT BASIN/
SOUTHERN PLATEAU REGION...THROUGH THE NORTHERN AND CENTRAL PLAINS BY
12Z SATURDAY. MODELS SUGGEST THAT THIS LATTER DEVELOPMENT WILL
OCCUR AS A STRONG UPSTREAM IMPULSE AND ASSOCIATED JET STREAK DIG
THROUGH THE NORTHEAST PACIFIC.


IN RESPONSE TO THE IMPULSE EMERGING FROM THE INTERMOUNTAIN
REGION...MODELS SUGGEST THAT A SURFACE CYCLONE MAY SLOWLY DEEPEN
OVER THE CENTRAL HIGH PLAINS DURING THE DAY TODAY...BEFORE A SURFACE
FRONT...EXTENDING NORTHEASTWARD THROUGH THE MID MISSOURI AND UPPER
MISSISSIPPI VALLEYS...STRENGTHENS AND BEGINS TO SURGE EASTWARD
ACROSS THE CENTRAL PLAINS TONIGHT. WHILE A RETURN FLOW OF GULF
MOISTURE IS IN THE PROCESS OF DEVELOPING ACROSS THE LOWER RIO GRANDE
VALLEY...SUBSTANTIVE BOUNDARY LAYER MOISTENING FROM THIS SOURCE
REGION MAY NOT REACH THE CENTRAL PLAINS UNTIL LATE THIS AFTERNOON OR
EVENING. HOWEVER...MOISTENING ACROSS THE SOUTHERN INTO CENTRAL HIGH
PLAINS DOES APPEAR LIKELY TO BE AUGMENTED BY AN INFLUX OF MOISTURE
OF LOWER LATITUDE EASTERN PACIFIC ORIGINS...ON SOUTHWESTERLY FLOW AT
LOWER/MID-LEVELS...AHEAD OF THE UPPER TROUGH.


...CENTRAL AND SOUTHERN PLAINS...
WHILE IT DOES APPEAR LIKELY THAT CONSIDERABLE LOW/MID-LEVEL
MOISTENING WILL OCCUR TODAY ALONG A PRE-FRONTAL SURFACE TROUGH
ACROSS THE SOUTHERN INTO CENTRAL HIGH PLAINS...AND ALONG THE FRONT
ACROSS NORTHEAST COLORADO THROUGH CENTRAL NEBRASKA...INITIALLY
MODESTLY STEEP MID-LEVEL LAPSE RATES MAY NOT BE MAINTAINED. AND
MODELS SUGGEST THAT SURFACE HEATING TODAY WILL BE MORE MODEST THAN
YESTERDAY...SO UNCERTAINTY EXISTS CONCERNING HOW FAVORABLE
THERMODYNAMIC PROFILES WILL BE FOR SEVERE WEATHER POTENTIAL.
STILL...GIVEN THE STRENGTHENING OF THE DEEP LAYER MEAN FLOW FIELDS
AND SHEAR AS THE UPPER IMPULSE PROGRESSES ACROSS THE ROCKIES LATE
THIS AFTERNOON AND EVENING... FAIRLY DEEP BOUNDARY LAYER
MIXING...AND THE EVOLUTION OF SIZABLE SUB-CLOUD TEMPERATURE/DEW
POINT SPREADS...SHOULD BE SUFFICIENT TO SUPPORT SEVERE WIND GUST
POTENTIAL.


ACROSS THE TEXAS PANHANDLE AND PARTS OF WESTERN OKLAHOMA INTO
WESTERN KANSAS...CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS ARE FORECAST
TO BE LARGE ENOUGH TO SUPPORT POTENTIAL FOR TORNADOES...
PARTICULARLY IN DISCRETE STORM DEVELOPMENT. SOUTH OF THE COLD
FRONT...THIS COULD BE THE PRIMARY STORM MODE INITIALLY.
HOWEVER...AS FRONTOGENETIC FORCING INCREASES ALONG THE EASTWARD AND
SOUTHEASTWARD SURGING COLD FRONT...AN ORGANIZING LINE OF STORMS
APPEARS POSSIBLE JUST AHEAD OF IT...FROM PARTS OF CENTRAL AND
SOUTHERN NEBRASKA SOUTHWARD THROUGH THE TEXAS PANHANDLE THIS
EVENING.


CONVECTION MAY PERSIST AHEAD OF THE FRONT ADVANCING TOWARD THE LOWER
PLAINS OVERNIGHT. HOWEVER...AS IT PROGRESSES THROUGH THE RELATIVELY
NARROW CORRIDOR OF PEAK LATE AFTERNOON BOUNDARY LAYER
DESTABILIZATION /CHARACTERIZED BY CAPE ON THE ORDER OF 1000 J PER
KG/...SEVERE WIND POTENTIAL IS EXPECTED TO DIMINISH EAST OF THE HIGH
PLAINS.


..KERR/PETERS.. 09/27/201

[Bunty]

Here's Reed Timmer's comments on the developing situation:

"Looks like an enhanced supercell and tornado threat could develop over in at least the Texas Panhandle region including Amarillo and Lubbock later this afternoon into evening, based on latest model data.

I also wouldn't be surprised to see some ropes to the north in NW KS - SW NE but moisture is lacking.

We're currently heading west to position. Models seem to hint at the usual rogue southern monster storm west of Lubbock near NM Border by 4-5 pm CDT, along with supercells along the dryline into western KS through the OK Panhandle as well."

[Bunty]

Meanwhile, winter storm warnings and advisories are in effect for parts of the Rocky Mountains in Wyoming, Colorado, Utah, and extreme southern Montana.  Winter time is arriving there earlier than usual.  So far, nothing real unusual in the forecast resulting from the front's passage for here. Lows are not supposed to drop below 50.

[Farmtalk]

Here's a couple model maps I've seen pertaining to this:

Some decent LI values, especially in northern TX, the OK panhandle, and southwestern KS.



CAPE values are fairly modest, with highest values at about 2000 J/Kg^2, but still more than enough

[BigOkie]

Slight risk today for roughly western 1/3rd of Oklahoma meaning hail, wind and tornadoes.  It will be interesting to see if a watch will have to be issued later.

***snipped for brevity***

Risk into the Day 2 outlook, albeit not as much.  But we all know how that can hash out 48 hours out.  Be diligent regardless.

ACUS02 KWNS 271713
SWODY2
SPC AC 271712

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT FRI SEP 27 2013

VALID 281200Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SW MO/NW AR/ERN OK/NE TX...
AN UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE GREAT PLAINS ON
SATURDAY AS A COLD FRONT ADVANCES SEWD INTO THE SRN PLAINS AND
OZARKS. SFC HEATING AND LOW-LEVEL CONVERGENCE JUST AHEAD OF THE
FRONT SHOULD RESULT IN STORM INITIATION SATURDAY AFTERNOON FROM
CNTRL MO SWWD INTO WCNTRL TX. MODEL FORECASTS SUGGEST THAT MODERATE
INSTABILITY MAY DEVELOP ALONG THIS CORRIDOR BY MID-AFTERNOON. THE
NAM IS THE MOST AGGRESSIVE WITH INSTABILITY SHOWING MLCAPE VALUES
AROUND 1500 J/KG FROM NE TX NNEWD INTO SW MO. THIS COMBINED WITH 30
KT OF 0-6 KM SHEAR MAY BE ENOUGH FOR A MARGINAL SEVERE THREAT.
STRONG GUSTY WINDS WILL BE POSSIBLE IF A LINE OF STRONG
THUNDERSTORMS CAN DEVELOP ACROSS THE REGION. ANY SEVERE THREAT WILL
BE DEPENDENT UPON HOW MUCH INSTABILITY DEVELOPS AHEAD OF THE COLD
FRONT.

...PACIFIC NORTHWEST...
AN UPPER-LEVEL TROUGH WILL MOVE QUICKLY ESEWD ACROSS THE NE PACIFIC
OCEAN APPROACHING THE WEST COAST OF NORTH AMERICA SATURDAY
AFTERNOON. THE EXIT REGION OF A 80 TO 100 KT MID-LEVEL JET WILL
OVERSPREAD THE PACIFIC NORTHWEST BRINGING WITH IT COPIOUS AMOUNTS OF
MID-LEVEL MOISTURE. AS A RESULT...THUNDERSTORMS COULD DEVELOP IN WRN
WA AND NW ORE DURING THE DAY DUE TO THE STRONG LARGE-SCALE ASCENT
ASSOCIATED WITH THE APPROACHING UPPER-LEVEL TROUGH. FORECAST
SOUNDINGS IN WRN WA SATURDAY AFTERNOON SHOW STRONG DEEP LAYER SHEAR
PROFILES AND CURVED HODOGRAPHS SUGGESTING A MARGINAL SEVERE THREAT
WILL BE POSSIBLE WITH CELLS THAT CAN EXHIBIT ROTATION.

..BROYLES.. 09/27/2013

[Farmtalk]

I'll keep watch for tomorrow then as well. Pretty juicy across this area, with dew points well into the 60s. Air temperatures approaching 90 throughout that area.

[BigOkie]

I'll keep watch for tomorrow then as well. Pretty juicy across this area, with dew points well into the 60s. Air temperatures approaching 90 throughout that area.

Dewpoints here in the low 60s/upper 50s.  The weather schleps on the toob were saying no credible threat of severe from the storms this weekend.  They've now backed off that and saying 'possible'.  Remember what Will Rogers said about Oklahoma weather.

Plus, the Tulsa State Fair started this weekend, so rainy forecasts are not so good for business.   

[cospringswx]

Temp here is in the 90's and dew point is in the low 60's. Windy here but thats normal. As Doug from Ardmore,OK would say "The fence is down". Saturday night will get down to 43. Pretty strong front.

[Farmtalk]

No elevated risks for severe weather for tomorrow according to the SPC, but I'll keep an eye on it.

Looking like according to the models, things will flair up around 21z, so I'll really start watching then.

[Farmtalk]

Mesoscale Discussion out now:

MESOSCALE DISCUSSION 1917
   NWS STORM PREDICTION CENTER NORMAN OK
   0344 PM CDT FRI SEP 27 2013

   AREAS AFFECTED...TX AND OK PANHANDLES THROUGH WRN KS

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

   VALID 272044Z - 272245Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...STORMS ARE EXPECTED TO DEVELOP BY 22-23Z FROM THE TX
   PANHANDLE NWD INTO WRN KS. INITIAL STORMS MAY DEVELOP SOME SUPERCELL
   STRUCTURES WITH A FEW LINE SEGMENTS ALSO LIKELY. ISOLATED LARGE HAIL
   AND DAMAGING WIND GUSTS ARE EXPECTED TO BE THE PRIMARY THREATS
   THROUGH MID EVENING.

   DISCUSSION...RECENT OBSERVATIONS INDICATE LOW-MID 60S DEWPOINTS
   ADVECTING NWD THROUGH WRN TX WITH UPPER 50S EVIDENT FARTHER NORTH
   ACROSS WRN KS. STRONG DIABATIC WARMING IS OCCURRING FROM WRN TX NWD
   INTO PORTIONS OF WRN AND CNTRL KS EAST OF MID-LEVEL CLOUD DECK
   ASSOCIATED WITH A PLUME OF SUBTROPICAL MOISTURE. HOWEVER...MID-LEVEL
   LAPSE RATES ARE NOT PARTICULARLY STEEP DUE PRIMARILY TO A LAYER OF
   WARM AIR ABOVE A RELATIVELY SHALLOW ELEVATED MIXED LAYER. MUCAPE
   RANGES FROM 1000 J/KG IN THE TX PANHANDLE TO BELOW 500 J/KG OVER WRN
   KS. SATELLITE DATA INDICATE A SUBSTANTIAL INCREASE IN BOUNDARY LAYER
   CUMULUS OVER THE TX PANHANDLE AND MID-LEVEL CONVECTION APPEARS TO BE
   DEEPENING WITHIN THE SUBTROPICAL MOISTURE PLUME JUST NW OF LUBBOCK.

   AS UPPER TROUGH OVER THE CNTRL ROCKIES SHIFTS EWD TOWARD THE HIGH
   PLAINS...ZONE OF PRE-FRONTAL CONVERGENCE SHOULD INCREASE FROM WRN TX
   THROUGH WRN KS. STORMS ARE EXPECTED TO DEVELOP IN THE NEXT COUPLE
   HOURS WITHIN AXIS OF BOUNDARY LAYER DESTABILIZATION ALONG ERN FRINGE
   OF SUBTROPICAL MOIST PLUME. DEEP LAYER VERTICAL SHEAR WILL
   STRENGTHEN AS MID-LEVEL JET ROTATES THROUGH BASE OF UPPER TROUGH
   SUPPORTING 40-50 KT EFFECTIVE SHEAR FROM THE TX PANHANDLE INTO WRN
   KS. DESPITE A SOMEWHAT MODEST THERMODYNAMIC ENVIRONMENT A FEW STORMS
   MAY DEVELOP SUPERCELL CHARACTERISTIC...POSSIBLY EVOLVING INTO LINE
   SEGMENTS...POSING A THREAT FOR ISOLATED DAMAGING WIND AND LARGE
   HAIL.

   ..DIAL/THOMPSON.. 09/27/2013


   ATTN...WFO...OUN...GID...DDC...GLD...LUB...AMA...

   LAT...LON   34430235 38650059 39459967 38579926 34330063 34430235

[Farmtalk]

Severe Thunderstorm Watch in effect now:

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 536
   NWS STORM PREDICTION CENTER NORMAN OK
   525 PM CDT FRI SEP 27 2013

   THE NWS STORM PREDICTION CENTER HAS ISSUED A

   * SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
     WESTERN KANSAS
     NORTHWEST OKLAHOMA INCLUDING THE PANHANDLE
     WESTERN AND NORTHWESTERN TEXAS INCLUDING THE PANHANDLE

   * EFFECTIVE THIS FRIDAY AFTERNOON AND SATURDAY MORNING FROM 525
     PM UNTIL 100 AM CDT.

   * PRIMARY THREATS INCLUDE...
     SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
     SEVERAL LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70
   STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH
   NORTHEAST OF GARDEN CITY KANSAS TO 50 MILES SOUTH OF LUBBOCK
   TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
   WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.

   &&

   DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
   INTENSITY THROUGH THIS EVENING...WITH THE POTENTIAL FOR A FEW
   SUPERCELLS AND SEVERAL LINE SEGMENTS.  DAMAGING WIND GUSTS AND HAIL
   WILL BE THE PRIMARY THREATS.

   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.
   A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION
   VECTOR 22030.

[cospringswx]

That would be me. The NWS said the weather should hit here around midnight.

[Farmtalk]

Storms definitely blowing up well to your southwest Ryan.

[cospringswx]

Line forming to the west of me too.

SOURCE...LAW ENFORCEMENT REPORTED NEAR ZERO VISIBILITY DUE TO STRONG
WIND AND BLOWING DUST ON INTERSTATE 70 NEAR THE COLORADO STATE LINE. TWO
SEMI TRAILERS HAVE BLOWN OVER ON INTERSTATE 70 JUST WEST OF KANORADO
KANSAS.

[Farmtalk]

Big time line starting to fire up to your west Ryan.

[cospringswx]

Yea I know! That is a nice image you got there. 

[cospringswx]

Here is my lame GR3 image! I can't compete with you pro's. 

[Farmtalk]

NOT lame, I bought an allisonhouse subscription for one month. I honestly probably won't due it again because I don't like recurring fees. Just GR by itself is a great program 

I'm seeing a couple of 50mph speeds on BV, but thankfully nothing higher and no warnings right now!

[cospringswx]

That's a pretty long line. Believe it or not I got stars over my house and lightning to the west right now. Line is about 30-40 miles west of me.

[Farmtalk]

Wow, BIG temperature change! I'm seeing Hays at 72 and Goodland at 48!