SVR Potential 3/10 - 3/12

[Thundersnow]

OHX thoughts for next week:

IN THE EXT FCST...
PATTERN TO BECOME MORE ACTIVE AND WET AS SEVERAL STORM SYSTEMS MOVE
ACROSS THE AREA. WILL INCLUDE ISOL TSTMS FOR WED AND THU AS COOLER
AIR ALOFT INTERACTS WITH GOOD LOW LEVEL WAA.

FOR THE EXT TEMPS...VALUES LOOKING ABOUT 5 DEGREES ABOVE NORMAL AS A
SOUTHERLY LOW LEVEL FLOW PREVAILS FOR THE BULK OF THE EXT PERIOD.

[Tom23]

From MRX (misspelled words courtesy of them): "BEST CHANCE OF SHOWERS THURSDAY INTO FRIDAY AS WARM AIR
ADVECTION AND COLD FRONT PASS THROUGH EASTERN TENNESSEE VALLEY.
THUNDERSTORMS LOOK POSSIBLE THURSDAY AND FRIDAY. UPPER LOW WOBBLES
EAST THROUGH OHIO VALLEY AS SURFACE LOW MOVES BY NORTH OF TN. COULLD
BE FIRST THREAT FOR SEVERE WEATHER THURSDAY AND FRIDAY TOO. LARGE
UPPER LEVEL SYSTEM WILL STAY NEAR FORECAST AREA THROUGH THE WEEKEND
WITH THREAT FOR SHOWERS CONTINUEING."

[Thundersnow]

MEG putting a word out there as well...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
337 PM CST SUN MAR 7 2010

.DISCUSSION...21Z SURFACE ANALYSIS PLACES A 1020 MB RIDGE OF HIGH
PRESSURE ACROSS THE SOUTHEAST UNITED STATES AND THE LOWER
MISSISSIPPI VALLEY. MEANWHILE A WEAK COLD FRONT IS LOCATED ACROSS
MISSOURI/ILLINOIS AND A DEVELOPING AREA OF LOW PRESSURE CENTERED
ACROSS SOUTHERN CALIFORNIA AND ARIZONA. AS OF 2 PM CST THIS
AFTERNOON TEMPERATURES ARE IN THE MIDDLE TO UPPER 60S ACROSS THE
FORECAST AREA WITH A FEW LOCATIONS IN THE MISSISSIPPI RIVER DELTA
CLOSE TO REACHING 70 DEGREES AS SOUTHERLY WINDS ON THE BACK SIDE
OF HIGH PRESSURE TRANSPORT WARM AIR BACK UP TO THE MID SOUTH UNDER
RELATIVELY SUNNY SKIES. STRONG TO SEVERE THUNDERSTORM POTENTIAL FOR
MID TO LATE WEEK IS THE MAIN CONCERN IN THIS AFTERNOON/S FORECAST
PACKAGE.
.
.
.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)...LAST COUPLE OF ECMWF/GFS
LONG RANGE MODELS CONTINUE TO INDICATE ANOTHER UPPER LEVEL LOW AND
ASSOCIATED UPPER LEVEL TROUGH AXIS ROTATING NEGATIVELY TILTED
THROUGH THE FORECAST AREA WEDNESDAY NIGHT INTO THURSDAY ACROSS
THE LOWER MISSISSIPPI VALLEY. THIS WILL PRODUCE ADDITIONAL CHANCES
FOR SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. THE
POTENTIAL FOR A FEW STRONG AND PERHAPS A SEVERE THUNDERSTORM EXISTS
WEDNESDAY NIGHT AS A WARM AND MOIST...UNSTABLE AIRMASS COMBINES
WITH FAVORABLE UPPER LEVEL DIVERGENCE /LIFT/ PRODUCED BY THE LEFT
EXIT REGION OF AN UPPER LEVEL JET STREAK. OVERALL CONFIDENCE IN
SEVERE THUNDERSTORMS REMAINS ON THE LOW SIDE FOR THIS FORECAST
PACKAGE AND WILL ONLY MENTION THE POTENTIAL FOR STRONG
THUNDERSTORMS IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW. LATER SHIFTS
WILL CONTINUE TO ASSESS STRONG/SEVERE THUNDERSTORM POTENTIAL FOR
WEDNESDAY NIGHT AS THIS POTENTIAL EVENT DRAWS CLOSER. STAY
TUNED...

OHX doesn't say much of anything about this possibility though.

[toastido]

HUN says not so fast...but has a very detailed AFD:

MONDAY NIGHT THROUGH WEDNESDAY...
THE UPPER LOW IN SO CAL WILL PIVOT NEWD INTO THE CENTRAL PLAINS
INDUCING LEE CYCLOGENESIS IN KS/OK. A NARROW SHORTWAVE TROF
ATTACHED TO THE TROF WILL BRING DPVA IN SYNC WITH MODERATE TO
STRONG 8-7H THETA-E ADVECTION MONDAY NIGHT INTO TUE. 8-5H LAPSE
RATES WILL STEEPEN ENUF TO GENERATE SI`S OF 0 TO -2 ACROSS THE
MID/LWR MS VALLEY REGION AS THIS WAVE MOVES THROUGH. EXPECT A
NEARLY SOLID BAND OF ELEVATED CONVECTION...MOSTLY SHRA BUT WITH
EMBEDDED TS...LATE MON NIGHT INTO MOST OF TUE. THERE MAY BE A
SECOND WAVE TUE NIGHT INTO WED...BUT THIS ONE IS LESS DEFINED...SO
HAVE KEPT POPS IN CHC RANGE. ALL THE MODELS CONTINUE TO SIGNAL
LARGE SCALE MCS DEVELOPMENT ALONG THE GULF COAST ON WED ALONG AND
N OF THE SFC WARM FRONT. LIGHTER PRECIP AND CLOUDS WILL COVER THE
TN VALLEY ON WED.  GIVEN PLENTY OF RAIN COOLED AIR IN THE BOUNDARY
LAYER/LOW LEVELS...HAVE CUT MAX TEMPS FROM GUIDANCE TO MUCH CLOSER
TO RAW MODEL OUTPUT.

WEDNESDAY NIGHT THROUGH THURSDAY...
AS THE INITIAL CLOSED LOW PIVOTS NWWD INTO THE NRN PLAINS...YET
ANOTHER SRN STREAM SHORTWAVE TRANSLATES BRISKLY ACROSS THE SRN
PLAINS AND INTO THE DEEP/MID SOUTH WED NIGHT. THIS INDUCES A SFC
CYCLONE SOMEWHERE IN THE MID SOUTH OR OZARKS. PREVIOUS OPER GFS
DATA SUGGESTED THIS LOW WOULD TRACK THRU OR NEAR THE SHOALS THU
MORNING...WHILE MANY OF OTHER GFS ENSEMBLE MEMBERS/ECWMF/GEM
OCCLUDED THE LOW FURTHER NW INTO MO. THE 12Z GFS IS FOLLOWING
SUIT. SELY GRADIENT FLOW WILL INTENSIFY TUE NIGHT AS THE LOW
DEEPENS TO AROUND 990 MB IN SERN MO. POPS WILL REMAIN HIGH FOR A
CONVECTIVE EVENT WED NIGHT/EARLY THU SUPPORTED BY A STRONG NEG
TILT SHORTWAVE...AMPLE DEEP LAYER -DIV Q...AND CONSIDERABLE
MOISTURE TRANSPORT/STRONG LLJ. WIDESPREAD PRE-FRONTAL AND FRONTAL
CONVECTION SHOULD INITIATE IN THE MS VALLEY EARLY WED
EVENING...THEN MOVE RAPIDLY NEWD OVERNIGHT INTO EARLY THUR. THE
OUTLIER IN THIS CASE IS THE GEM WHICH PRODUCES A STRONG DRY SLOT
WHICH "SPLITS" THE PRECIP AREAS INTO A BI-MODAL EVENT...ONE TO OUR
S/SE AND ANOTHER TO OUR NW. THIS CANNOT BE RULED OUT. REGARDING
THE THREAT OF STG-SVR WX...SFC BASED INSTABILITY WILL BE RELEGATED
TO THE WARM SECTOR WHICH SHOULD REMAIN TO OUR S UNTIL THUR
MORNING. BY THEN...THE CONVECTION MAY HAVE ALREADY EXITED TO OUR
NE. HOWEVER...GIVEN HIGH AMOUNTS OF EFFECTIVE DEEP LAYER AND LOW
LEVEL SHEAR PRESENT COINCIDENT WITH STEEPENING MID LEVEL LAPSE
RATES...THE THREAT FOR STRONG WINDS WILL BE POSSIBLE. THIS WAS
ALREADY ADDRESSED IN THE HWO...AND MORE DETAILS WILL BE ADDED IN
SUCCESSIVE OUTLOOKS AS NECESSARY EARLY THIS WEEK.
&&

[Charles L.]

Dr. Forbes is thinking we could have, at least, an isolated severe weather day on Wednesday into Thursday...

OHX should put some mention of it in tomorrow's AFD and they should also put out a HWO on the threat too.

[tennessee storm09]

i may be wrong, but i dont look for any serious threats of severe untill april. this cold winter has really put a hurt on the gulf. its going to take some time to heal from the prolong cold winter we had.

[Charles L.]

SPC has a threat out for Wednesday to the SE of us and that will spread eastward Wednesday night into Thursday. The western areas of middle TN stand the best chance at seeing some strong to severe storms with this setup. But if this slows down anymore and decides to come through TN during the day Thursday then we could have our own share of problems...

[StormNine]

i may be wrong, but i dont look for any serious threats of severe untill april. this cold winter has really put a hurt on the gulf. its going to take some time to heal from the prolong cold winter we had.

I think with the active sub tropical jet, and the polar jet being pushed far south this spring I think we will have an active severe wx season, but I think it will come pretty late.

The words delayed but not denied may be the message to describe this.  The north and central gulf have been stabbed with cold fronts all winter long.  The temps. in the gulf are now in the upper 50's and lower 60's not necessary the ideal warm gulf moisture source.

We may due to some shear need to watch for an isolated strong storm on Thursday, but I don't think we warm the kettle up for many areas till April(possibly not till April 25th or later for areas north of US 68 in KY)

[Eric]

Since we're in the throes of spring break here at MTSU, there really isn't much cookin', so I figured I'd post an overview of the severe threat highlighted by the SPC.  I hope to be able to do this more as the season progresses.  This is not meant to be a forecast by any stretch...but only my interpretation of data presented by various models.  As always, your thoughts and opinions are welcomed.



It looks like the severe weather season is about to kicik off, especially for our neighbors to the southwest of us.  The SPC has issued a SLGT severe risk for ArkLaTex region into and across the mid MS Valley...


...with a 30% probability of severe weather across the bootheel of LA and the southern half of AR.


Here's the text from the SPC:

...EAST TX/SOUTHEAST OK TO LOWER MS RIVER VALLEY...
   IN ASSOCIATION WITH A POTENT UPPER TROUGH THAT IS FORECAST TO
   ADVANCE NORTHEASTWARD FROM THE SOUTHERN HIGH PLAINS TO THE OZARKS
   VICINITY...IT APPEARS AN APPRECIABLE SEVERE POTENTIAL WILL EXIST
   ACROSS PORTIONS OF EAST TX/SOUTHEAST OK TO THE ARKLATEX/LOWER MS
   RIVER VALLEY ON WEDNESDAY. WITH A RELATIVELY MOIST AIRMASS REMAINING
   IN PLACE ACROSS THE ARKLATEX/LOWER MS VALLEY IN THE WAKE OF
   TODAYS/TUESDAYS UPPER TROUGH OVER THE MIDWEST...INCREASING LARGE
   SCALE FORCING FOR ASCENT/STRENGTHENING WIND FIELDS ALOFT SHOULD
   SUPPORT INCREASING SEVERE TSTM DEVELOPMENT DURING THE MID/LATE
   AFTERNOON HOURS OF WEDNESDAY INITIALLY ACROSS THE ARKLATEX VICINITY.
   SUFFICIENT LOW LEVEL MOISTURE/INSTABILITY AND STRONG/VEERING FLOW
   THROUGH THE LOW/MID TROPOSPHERE WILL SUPPORT AN INITIAL MODE OF
   SUPERCELLS WITH SEVERE HAIL/TORNADO POTENTIAL. BUT GIVEN THE DEGREE
   OF LARGE SCALE FORCING/HEIGHT FALLS...IT SEEMS LIKELY THAT STORMS
   SHOULD EVOLVE INTO A QUASI-LINEAR CONVECTIVE SYSTEM BY EARLY
   EVENING...WITH A CONTINUED DAMAGING WIND/TORNADO RISK QUICKLY
   SPREADING EAST-NORTHEASTWARD TOWARD THE LOWER MS RIVER VALLEY.
   ADDITIONAL BOUTS OF SEVERE TSTMS WILL ALSO BE POSSIBLE FARTHER
   SOUTHEAST ALONG THE CENTRAL GULF COAST VICINITY...PERHAPS MAINLY
   WEDNESDAY NIGHT.

Here is the 06z GFS, hour 66, valid for 6pm on Wednesday and you can clearly see gulf moisture streaming in thanks to the surface low parked over the OK panhandle.  



Here's the 06z GFS skew-T progged for Shreveport at hour 66...


According to the skew-T, there should be a fairly substantial amount of CAPE (~1200 j/kg) and decent surface dew point levels (~60F) so the severe threat is tangible.

At H5, an upper level trough wants to rotate through the ArkLaTex, which appears to be the impetus for this severe "event".  Not only will it provide the "match", it beings a southwesterly wind component which only adds to the possibility of a threat.


H3 analysis shows a rather vigorous jet max (~90kts) that wants to rotate through the bottom of the upper level trough, but doesn't appear to rotate all the way through the trough as it exits near the bottom.  This should provide enough upper level forcing to at least get the storms going.


If any storm can fire early enough ahead of the forcing mentioned by the SPC, it could take on supercellular characteristics.  However, I think that will be limited by the surface dew points only sitting around 60F.  If the dew points were higher, say 65F, the threat increases.

[Charles L.]

OHX's morning HWO, I am posting this because I wanted to point out the "newly" added spotter reporting criteria to the HWO.

000
FLUS44 KOHX 081108
HWOOHX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
508 AM CST MON MAR 8 2010

TNZ005>011-022>034-056>066-075-077>080-093>095-091115-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DEKALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
508 AM CST MON MAR 8 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

AN UNSETTLED WEATHER PATTERN WILL DEVELOP OVER THE REGION WITH ON
AND OFF CHANCES FOR THUNDERSTORMS TUESDAY NIGHT THROUGH FRIDAY.
A FEW OF THE STORMS COULD BE STRONG TO SEVERE THROUGH THIS PERIOD.
THE GREATEST PROBABILITY FOR SEVERE WEATHER WILL OCCUR WEDNESDAY
EVENING THROUGH EARLY THURSDAY MORNING WITH A STRONG LOW PRESSURE
AND COLD FRONT CROSSING THE REGION.

.SPOTTER INFORMATION STATEMENT...

EVEN THOUGH ANY SEVERE THUNDERSTORMS ARE EXPECTED TO BE BRIEF AND
ISOLATED, SPOTTERS ARE ENCOURAGED TO CLOSELY MONITOR WEATHER
CONDITIONS AND BE PREPARED TO CALL IN ANYTHING REACHING REPORTING
CRITERIA.

$$

SPOTTER THUNDERSTORM REPORTING CRITERIA...
TORNADO
FUNNEL CLOUD
FLOODING
HAIL >= 1/2 INCH
WINDS > 50 MPH (MEASURED)
STRUCTURAL DAMAGE
TREES OR POWER LINES DOWN

I like how they have added that in their HWO, even though spotters should know this, it helps to have it in there just in case.

[Tom23]

Great info Wkuweather. I think a majority (including, surprisingly, me) of us know this criteria, BUT its a good thing to know for future references.

[Thundersnow]

I went ahead and split off this topic for discussing the severe potential this week.  I'm not sure how widespread or high a concern it is (chances seem greater SW of the state), but since WFOs and the SPC have been discussing it, we'll keep an eye on it, especially considering this AFD out of MEG this afternoon:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
356 PM CST MON MAR 8 2010

.DISCUSSION...

STRONG/SEVERE THUNDERSTORM POTENTIAL TUESDAY THROUGH WEDNESDAY
NIGHT IS THE MAIN CONCERN.

LATEST MODELS WERE IN GOOD GENERAL AGREEMENT. USED A BLEND OF THEM
WITH NO PREFERENCE TO ONE MODEL OVER ANOTHER.

DID NOT MAKE ANY SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST.

AT 345 PM ACROSS THE MIDSOUTH AND FORECAST AREA...WARM AND SUNNY
CONDITIONS WERE OCCURRING WITH TEMPERATURES MAINLY IN THE LOWER TO
MID 70S...HIGHEST READINGS SINCE NOVEMBER 2009. HIGH PRESSURE WAS
OVER THE NORTHEAST GULF OF MEXICO WHILE LOW PRESSURE WAS NEAR THE
TEXAS PANHANDLE.

TONIGHT...CLOUDS WILL RAPIDLY INCREASE WEST TO EAST. THINK SHOWERS
WILL MOVE INTO THE AREA WEST TO EAST...ARRIVING SOMEWHERE IN THE
11 PM TO 2 AM WEST OF THE MISSISSIPPI RIVER...AND OVERSPREADING
MUCH OF THE AREA BY 7 AM. GENERALLY WENT ABOVE GUIDANCE RAIN
CHANCES EXCEPT EAST OF A JACKSON TN TO TUPELO MS LINE WHERE
SHOWERS MAY BE SLOW TO ARRIVE AS THEY ENCOUNTER DRIER AIR. KEPT
THUNDER MENTION OUT OF FORECAST WITH MUCAPES LESS THAN 100 J/KG.
WENT NEAR MODEL GUIDANCE FOR LOWS MAINLY IN THE UPPER 40S TO
LOWER 50S.

TUESDAY MORNING...SHOWERS WILL EXIT THE AREA WEST TO
EAST...LEAVING MOSTLY CLOUDY SKIES. GENERALLY WENT WITH OR
SLIGHTLY ABOVE 12Z MAVMOS FOR RAIN CHANCES ON TUESDAY.

TUESDAY AFTERNOON AND NIGHT...WILL MONITOR REDEVELOPMENT OF SHOWERS
AND THUNDERSTORMS. LATEST MODELS HINTED AT THIS REDEVELOPMENT
WHICH MAKES SENSE CONSIDERING THEY DEPICTED SOME LIFT AND MOISTURE
OVER THE AREA. CONCERNED THAT MID/UPPER DRY SLOT MAY ALLOW OR SOME
CLEARING DURING THE AFTERNOON...ESPECIALLY WEST OF I-55...WHICH
COULD ALLOW FOR SOME DESTABILIZATION. WITH MUCAPE FORECAST AROUND
500 J/KG ALONG WITH SURFACE PRESSURE AND 500 MB HEIGHT FALLS...
THINK THERE WILL SOME THUNDERSTORM DEVELOPMENT LATE AFTERNOON AND
NIGHT OVER THE AREA. SOME OF THESE STORMS COULD BE STRONG TO
PERHAPS SEVERE IF THEY CAN BECOME SURFACE BASED. LATEST SPC DAY 2
SEE TEXT 5% AREA HANDLES THIS SCENARIO. NOT SURE IF THEY WILL
BECOME SURFACE BASED AT THIS TIME...BUT ADDED STRONG STORM MENTION
TO THE HWO WITH GUSTY WINDS...SMALL HAIL...AND HEAVY DOWNPOURS THE
MAIN HAZARDS. IF BETTER DESTABILIZATION OCCURS...WOULD HAVE TO
MONITOR FOR POSSIBLE SEVERE STORMS MAINLY BETWEEN 4 PM AND 10 PM
ALONG AND WEST OF I-55 WITH DAMAGING WIND AND EVEN A POSSIBLE
TORNADO OR TWO POSSIBLE. FARTHER EAST...CHANCES FOR SEVERE/SURFACE
BASED CONVECTION APPEAR TO BE MUCH LOWER. WILL CLOSELY MONITOR.
GENERALLY WENT WITH THE WARMER SIDE OF GUIDANCE FOR TEMPERATURES
AND ACCEPTED 12Z MAVMOS RAIN CHANCES TUESDAY NIGHT.

WEDNESDAY THROUGH WEDNESDAY NIGHT...WILL CLOSELY MONITOR
STRONG/SEVERE THUNDERSTORM DEVELOPMENT MAINLY WEDNESDAY NIGHT.
LATEST MODELS WERE IN GOOD AGREEMENT OF THE PROGRESSION A SURFACE
LOW TO OUR NORTHWEST. THINK CURRENT SLIGHT RISK AREA SOUTHWEST OF
A WYNNE AR TO BATESVILLE MS LINE IS IN GOOD SHAPE AS BEST SEVERE
DEVELOPMENT WILL BE IN THESE SOUTHWEST AREAS...IF NOT EVEN FARTHER
SOUTHWEST. GETTING SURFACE BASED CONVECTION WILL BE CONCERN OVER
MUCH OF THE AREA AS CONVECTION IS EXPECTED TO OCCUR AT NIGHT.
ISOLATED DAMAGING WIND GUSTS WOULD PROBABLY BE THE BIGGEST HAZARD
IF SEVERE WOULD TO OCCUR AS STORMS WOULD LIKELY BE LINEAR BY TIME
THEY REACH THE MIDSOUTH...BUT MAY BE DIFFICULT TO GET SEVERE WINDS
AT THE SURFACE AT NIGHT. ADDED HEAVY RAINFALL AND LOCALIZED
FLOODING TO HWO THINKING AIR WILL BE QUITE JUICY FOR THIS TIME OF
YEAR WITH PW UP TO 1.5 INCHES...ABOUT 3 TIMES OF NORMAL...AND
POSSIBLE RAINFALL RATES OF 1 INCH/HOUR OR GREATER.

THURSDAY THROUGH THURSDAY NIGHT...AREA WILL BE MID/UPPER LEVEL DRY
SLOT DURING THE DAY ON THURSDAY...WHICH SHOULD ALLOW TEMPERATURES
TO TAKE OFF...THUS RAISED THEM CONSIDERABLY. APPEARS MID/UPPER
LEVEL DISTURBANCE WILL MOVE THROUGH THURSDAY NIGHT WHICH MAY BRING
ADDITIONAL SHOWERS AND THUNDERSTORMS AS THE AIR MAY BE A BIT
UNSTABLE. 12Z MEXMOS RAIN CHANCES APPEARED REASONABLE.

FRIDAY THROUGH NEXT MONDAY...MOSTLY CLOUDY AND COOL CONDITIONS ARE
EXPECTED DURING THIS TIME FRAME WITH MID/UPPER LOW NEARBY. KEPT
LOW CHANCES FOR SHOWERS FRIDAY AND SATURDAY. SLIGHTLY BELOW AVERAGE
TEMPERATURES ARE EXPECTED.

MBS

[Tom23]

From MRX's afternoon AFD: "FOR FRIDAY...SEVERE THUNDERSTORMS WILL BE POSSIBLE. A COLD FRONT
WILL MOVE ACROSS THE AREA FRIDAY AFTERNOON WITH AN UPPER TROUGH AND
ASSOCIATED COLD AIR ALOFT SETTING THE STAGE FOR CONVECTION.
DEPENDING ON HOW MUCH INSOLATION OCCURS BEFORE FRONTAL PASSAGE AND
TIMING OF FRONT...AIRMASS MAY BE UNSTABLE ENOUGH TO PRODUCE SEVERE
STORMS WITH THE MAIN THREAT BEING LARGE HAIL AND DAMAGING WINDS.

[Thundersnow]

Well, the system is already producing... in Oklahoma:

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
559 PM CST MON MAR 8 2010

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN CUSTER COUNTY IN WESTERN OKLAHOMA...
  EASTERN ROGER MILLS COUNTY IN WESTERN OKLAHOMA...

* UNTIL 630 PM CST

* AT 557 PM CST...RADAR AND STORM SPOTTERS OBSERVED A TORNADO NEAR
  MOVING ACROSS HIGHWAY 34 NEAR HAMMON. THE STORM WAS MOVING
  NORTHEAST AT 35 MPH. DAMAGE HAS BEEN REPORTED IN THE HAMMON AREA
  WITH THIS TORNADO.

* LOCATIONS IN THE WARNING INCLUDE BUTLER AND HAMMON AND AREAS TO
  THE NORTHEAST OF FOSS LAKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. LEAVE MOBILE HOMES AND VEHICLES. IF POSSIBLE...MOVE
TO A BASEMENT OR STORM SHELTER. OTHERWISE MOVE TO AN INTERIOR ROOM OR
HALLWAY ON THE LOWEST FLOOR. STAY AWAY FROM WINDOWS AND OUTSIDE
WALLS.

Apparently, the Gulf being knocked down by the cold air masses this winter isn't a completely limiting factor.

[Tom23]

Well, I'm not knowledgeable on this subject, but it does appear that way Thundersnow.