Mar 1-3 SE Severe Weather, SPC Risk Level: Day 1 High Risk - Forecasts & OBS Options

[31B militaryPoli...]

Went ahead and made this thread to keep this system's discussion out of the other thread. Felt like the 0Z guidance yesterday evening and night did a good job in coming to a generally good consensus with evolution and track of short waves, and SFC cyclogenesis. However, SPC keeps their predictability too low text. I feel there is enough confidence that there will be system move through the mid section of the country, bringing at least some kind of threat for severe weather across the Deep South to Southeast later this week...Models are showing a strong SFC cyclogenesis over Kansas rapidly deepening as it tracks towards the GL region...Out ahead of the system we have WSW winds aloft in the mid-levels which supports an EML moving over the large warm sector this should limit any premature convection until the CAP can break during peak heating hours, once then instability won't be seen as a problem with 60+ Tds all the way into the Ohio Valley region, and models already painting 1000+ J/KG CAPE Values across Deep South/Dixie alley with LI in the -4 to -7 range. With strong LLJ in 50-60KT range coming from the SSW with near 90 degree turn at 500MB as winds come out of the WSW, are yielding some long clockwise hodograph signatures. So as of right now all modes of severe weather look possible with this system...With that said, this is still 4-6 days out, and there is time for such a significant severe weather event to not materialize as some models have been painting the past few days now, although at the very least a marginal severe weather event is looking likely now. Still not liking the trends on the models, the 12Z Euro is rather very ominous...

SPC:

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0346 AM CST MON FEB 27 2012

VALID 011200Z - 061200Z

...DISCUSSION...
IN MID-UPPER LEVELS...PAC JET MAX MOVING INTO GREAT BASIN REGION
SHOULD CONTRIBUTE TO DAY-4/1ST-2ND AMPLIFICATION OF WRN-CONUS
SYNOPTIC-SCALE TROUGHING. THIS WILL YIELD SIGNIFICANT SFC
CYCLOGENESIS OVER CENTRAL HIGH PLAINS. HOWEVER...CONSIDERABLE
DIFFERENCES IN SHORTWAVE DETAILS AMONGST MREF MEMBERS...AND BETWEEN
OPERATIONAL SPECTRAL/UKMET/ECMWF...RESULT IN GREAT VARIATION OF
TIMING/DEPTH/TRACK OF THIS LOW...AND OF RELATED BOUNDARIES. THESE
DISCREPANCIES SPREAD APART EVEN MORE DAY-5/2ND-3RD. POLEWARD EXTENT
OF FAVORABLE MOISTURE RETURN ALSO IS IN QUESTION FOLLOWING PASSAGE
OF COLD FRONT DESCRIBED IN DAY-3 OUTLOOK. SOME SVR IS LIKELY DURING
DAY-4/DAY-5 TIME FRAME...GENERALLY FROM SRN PLAINS TO LOWER/MID MS
VALLEY AND OH VALLEY REGIONS. ATTM...HOWEVER...THERE IS TOO MUCH
UNCERTAINTY TO NAIL DOWN SPECIFIC AREA OF 30% UNCONDITIONAL
PROBABILITIES.

[andyhb]

I'm thinking this and the OV threads should be merged, since it honestly is looking like both regions will be affected.

[jdrenken]

I'm thinking this and the OV threads should be merged, since it honestly is looking like both regions will be affected.

We will have an OV thread separate.

[31B militaryPoli...]

BMX Afternoon thoughts:

AT THE SURFACE THE GFS SHOWS VIGOROUS DEEPENING OF THE SURFACE LOW
AS IT MOVES FROM SOUTHERN KANSAS TO THE GREAT LAKES...FROM 995 MB
12Z FRIDAY TO 971 MB 06 Z SATURDAY. THE SEVERE WEATHER THREAT WILL
BE HIGHER IF THIS SOLUTION VERIFIES...BUT IT WILL ALL DEPEND ON THE
EVOLUTION OF THE MID/UPPER LEVEL TROUGH. AN UPPER LEVEL JET MAX WILL
APPROACH FROM THE SOUTHERN PLAINS BY FRIDAY AFTERNOON LEADING TO
DIFFLUENCE ALOFT OVER OUR REGION. AS OPPOSED TO LINEAR FORCING...THE
BROAD NATURE OF THE LARGE SCALE ASCENT ASSOCIATED WITH APPROACHING
JET MAX SUPPORTS THE IDEA OF SUPERCELL DEVELOPMENT BY LATE FRIDAY
AFTERNOON ACROSS MISSISSIPPI AND NORTHWEST ALABAMA. CAPE VALUES OF
1200 TO 1800 J/KG AND WESTERLY 0-6 KM SHEAR OF 65 TO 75 KNOTS
CROSSING THE WARM SECTOR ALSO ARGUES FOR SUPERCELL DEVELOPMENT IN
THE EARLY STAGES OF THIS EVENT. IF A STRONG SURFACE LOW FORMS AS
DEPICTED BY THE GFS...THE RAPID DEEPENING OF THE SURFACE LOW AND
VIGOROUS PRESSURE TROUGH ASSOCIATED WITH THE FRONT WOULD ALLOW FOR
BACKING SURFACE WINDS DURING THE LATE AFTERNOON. 0-1 KM HELICITY
VALUES IN EXCESS OF 400 M2/S2 ARE NOTED ON THE GFS LATE FRIDAY
AFTERNOON ACROSS THE NORTHWEST PART OF THE AREA WHERE SUPERCELL
DEVELOPMENT IS POSSIBLE...AND THIS COULD LEAD TO AN ENHANCED TORNADO
THREAT. STRONG WIND PROFILES WILL ALSO SUPPORT A DAMAGING WIND
THREAT...AND LARGE HAIL WILL ALSO BE POSSIBLE. AT THIS TIME...THE
BEST THREAT APPEARS TO BE ACROSS THE NORTHERN HALF OF THE AREA FOR
FRIDAY AFTERNOON AND EVENING. A TRANSITION TOWARD A SQUALL IS
EXPECTED OVERNIGHT AS THE FORCING BECOMES MORE ASSOCIATED WITH THE
COLD FRONT. HELICITY VALUES MAY REMAIN QUITE HIGH AS A 60 KT LOW
LEVEL JET DEVELOPS AND THIS WOULD SUPPORT A CONTINUING DAMAGING WIND
AND TORNADO THREAT AS THE LINE MOVES ACROSS THE STATE. THE FRONT
SHOULD CLEAR THE AREA BY NOON SATURDAY LEADING TO MUCH DRIER AND
COOLER CONDITIONS AND ENDING THE SEVERE WEATHER THREAT. WITH THIS
SYSTEM STILL 3 DAYS AWAY...THE AFOREMENTIONED POSSIBLE EVOLUTION OF
THIS EVENT IS SUBJECT TO CHANGE.

GRANTHAM/87

[31B militaryPoli...]

SPC Day 3:

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0223 AM CST WED FEB 29 2012

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS OH VALLEY STATES TO
CENTRAL/SRN APPALACHIANS AND LOWER MS RIVER REGION...

...SYNOPSIS...
WRN-CONUS SYNOPTIC-SCALE TROUGHING DESCRIBED IN DAY-2 OUTLOOK IS
FCST TO PROGRESS EWD ACROSS CENTRAL CONUS DAY-3. BY 3/00Z...TROUGH
SHOULD EXHIBIT STG POSITIVE TILT...EXTENDING FROM MID-UPPER LOW OVER
MN/ONT BORDER REGION SWWD ACROSS CENTRAL PLAINS TO BASAL SHORTWAVE
TROUGH OVER NRN NM. NEAR END OF PERIOD...CONSENSUS OF
OPERATIONAL/SREF GUIDANCE REASONABLY POSITIONS TROUGHING ALOFT FROM
N OF LH SWWD ACROSS PORTIONS IA/MO/OK TO SRN NM/FAR W TX REGION.

AT SFC...2/12Z CYCLONE SHOULD BE POSITIONED INVOF SWRN MO...AS
FRONTAL WAVE PERTURBED BY WEAK/LEADING MIDLEVEL SHORTWAVE. SFC LOW
IS EXPECTED TO MOVE NEWD AND DEEPEN THROUGHOUT DAYLIGHT
HOURS...REACHING NWRN INDIANA/WRN LOWER MI AREA BY 3/00Z. AT THAT
TIME...COLD FRONT SHOULD EXTEND SWWD ACROSS INDIANA...AR...AND
CENTRAL TX...WITH WARM FRONT SEWD INTO CENTRAL APPALACHIANS. THIS
WARM FRONT WILL BE SEPARATE FROM DAY-2 VERSION OVER SRN PLAINS/LOWER
MS VALLEY REGION...THAT WILL HAVE DISSIPATED BY EARLY DAY-3. BY
3/12Z...COLD FRONT SHOULD REACH WRN NY...CENTRAL/SRN
APALACHIANS...CENTRAL/SRN MS AND UPPER TX COAST.

...MS/GA/AL TO OH VALLEY STATES...
GROUPS OF TSTMS MAY CARRY OVER FROM DAY-2 PERIOD OVER PORTIONS
MID-MS VALLEY TO MID-SOUTH REGIONS...MOVING NEWD TOWARD OH VALLEY
STATES. WHILE THIS ACTIVITY MAY BE ELEVATED INITIALLY...COMBINATION
OF DIABATIC HEATING AND STG BOUNDARY-LAYER THETAE ADVECTION SHOULD
DESTABILIZE FOREGOING AIR MASS ENOUGH TO YIELD SFC-BASED EFFECTIVE
INFLOW PARCELS. STG DEEP-LAYER SPEED SHEAR AND MID-UPPER WIND
SPEEDS INDICATE FAST STORM MOTIONS ARE LIKELY...POTENTIALLY AOA 50
KT...WITH DAMAGING GUSTS COMPRISING BULK OF SVR EVENTS...AND
TORNADOES ALSO POSSIBLE.

ANOTHER AREA OF TSTMS WITH WIND DAMAGE/TORNADO POTENTIAL SHOULD
DEVELOP ALONG/AHEAD OF SFC COLD FRONT FROM LATE AFTERNOON INTO
OVERNIGHT HOURS...OVER PORTIONS KY/TN/MS...IN FAVORABLE
BOUNDARY-LAYER MOISTURE. THIS ACTIVITY EVENTUALLY SHOULD EVOLVE TO
QUASI-LINEAR GIVEN NEARLY PARALLEL NATURE OF MEAN FLOW WITH RESPECT
TO ZONE OF LOW-LEVEL ASCENT. HOWEVER...VERY STG LOW-LEVEL AND
DEEP-LAYER SHEAR...ESPECIALLY DURING EVENING OVER PORTIONS KY/TN AND
NRN MS/NWRN AL...INDICATE FIRST FEW HOURS OF CONVECTIVE REGIME MAY
INVOLVE FAST-MOVING/SFC-BASED SUPERCELLS AND ACCORDINGLY ENHANCED
TORNADO POTENTIAL. EXTENT TO WHICH THIS REGIME WILL LINK WITH
EARLIER/OH VALLEY CONVECTION IS UNCERTAIN...AS ARE IMPORTANT MODE
CONSIDERATIONS SUCH AS PACE OF LINEAR EVOLUTION. UNCERTAINTY
REGARDING HOW FAR SW BACKBUILDING WILL OCCUR...INTO PROGRESSIVELY
STRONGER CAPPING AND WEAKER LOW-LEVEL CONVERGENCE...IS MANIFEST AS
DECREASING UNCONDITIONAL PROBABILITIES OVER LA AND E TX.

..EDWARDS.. 02/29/2012

[31B militaryPoli...]

If the 12Z GFS verifies...you have pressure falls all the way down the Cold-Front, with a secondary low that develops in S AR and tracks through TN. Large warm sector with 55+ Tds lifting into Ohio Valley 60+ Tds in Tennessee Valley, combined with SBCAPE up near 1250 J/KG; LIs down to -7. Strengthening LLJ up to 50-60Kts from SW and mid-level jet AOA 70Kts from SSW yields long clockwise curved hodo signatures at 0-3KM with helicity values in the 300-450 M2/S2 range supports discrete supercell thunderstorms with tornadoes. Turning in the lowest atmosphere with 0-1KM helicity values AOA 300 M2/S2 combined with LCL levels less than 500M tells me an enhanced tornado risk is quite possible. The secondary SLP will lead to backing of the surface winds, and wouldn't be surprised if later models keep that solution there will be better hodographs shown.

All I can say is the 12Z GFS doesn't look good for MS/AL/GA/TN Friday evening into the night...

[northmiss]

If the 12Z GFS verifies...you have pressure falls all the way down the Cold-Front, with a secondary low that develops in S AR and tracks through TN. Large warm sector with 55+ Tds lifting into Ohio Valley 60+ Tds in Tennessee Valley, combined with SBCAPE up near 1250 J/KG; LIs down to -7. Strengthening LLJ up to 50-60Kts from SW and mid-level jet AOA 70Kts from SSW yields long clockwise curved hodo signatures at 0-3KM with helicity values in the 300-450 M2/S2 range supports discrete supercell thunderstorms with tornadoes. Turning in the lowest atmosphere with 0-1KM helicity values AOA 300 M2/S2 combined with LCL levels less than 500M tells me an enhanced tornado risk is quite possible. The secondary SLP will lead to backing of the surface winds, and wouldn't be surprised if later models keep that solution there will be better hodographs shown.

All I can say is the 12Z GFS doesn't look good for MS/AL/GA/TN Friday evening into the night...

From looking at the models, and I should say I have just begun to look at these types of things, does the worst not look farther north than north MS? I'm merely looking at basics (CAPE, STP, etc.) and just want to know if I'm any where in the ball park.

[northmiss]

Lazy tonight,where is Ripley ?

North Central MS pretty much right in the middle of the first row of counties.

This post has been edited by northmiss: Feb 29 2012, 10:21 PM

[Mid Tn. Man]

North Central MS pretty much right in the middle of the first row of counties.

Just by those two should concern you some

This post has been edited by Mid Tn. Man: Feb 29 2012, 10:47 PM

[Mid Tn. Man]

Nashville

[31B militaryPoli...]

From looking at the models, and I should say I have just begun to look at these types of things, does the worst not look farther north than north MS? I'm merely looking at basics (CAPE, STP, etc.) and just want to know if I'm any where in the ball park.

Yes, the models are painting quite a significant severe weather event for areas to our north specifically the Ohio Valley. With that said there is still the potential for a significant event, given models are correct so far, for areas further south i.e. AL/MS/GA/NC/SC. Models are showing strong pressure falls along and ahead of the front, and with the possibility of a secondary SLP tracking through TN would only make Friday evening and overnight more dangerous. As of right now there is still uncertainty if there will be a second SLP, both 0Z NAM/GFS were close to closing one off, and majority of the the latest SREF run members do have a second SLP. That will be one key feature that will play an important role in storm mode if you live say south of TN. Backing of surface winds will be what keeps storms more discrete in nature, than trying to go linear...

[Mid Tn. Man]

GFS 0Z Hasn't computed my LI yet but looking it's a -4,after the run i'll double check



This post has been edited by Mid Tn. Man: Mar 1 2012, 12:12 AM

[Mid Tn. Man]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1137 PM CST WED FEB 29 2012

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE MID MS
VALLEY AND THE LOWER OH VALLEY...

...MID MS/LOWER OH VALLEY REGION...

HEIGHT FALLS WILL OVERSPREAD THE GREAT BASIN/CNTRL ROCKIES DURING
THE DAY THURSDAY BEFORE SPREADING ACROSS THE CNTRL/SRN PLAINS INTO
THE MID MS VALLEY LATE IN THE PERIOD. LATEST MODEL GUIDANCE SUGGEST
A VERY STRONG MID LEVEL JET...INCREASING TO ROUGHLY 100KT...WILL DIG
INTO THE BASE OF THE TROUGH OVER NRN AZ/NM BEFORE EJECTING INTO NRN
OK BY 02/12Z. THIS FEATURE WILL UNDOUBTEDLY INDUCE LEE CYCLOGENESIS
OVER THE HIGH PLAINS WITH SUBSEQUENT MOVEMENT/DEEPENING INTO NERN OK
BY MIDNIGHT AND SWRN MO BY SUNRISE.

IN RESPONSE TO THIS FEATURE...THE OLD FRONTAL ZONE THAT HAS
TEMPORARILY STALLED NEAR I-20 OVER THE LOWER MS VALLEY WILL SURGE
NWD DURING THE LATTER HALF OF THE PERIOD WITH MODIFIED MARITIME
AIRMASS EXPECTED TO RETURN WITH THE WARM SECTOR TO AT LEAST THE
MO/AR BORDER BY 02/12Z. LATEST THINKING IS LARGE SCALE FORCING WILL
INITIALLY BE WEAK ALONG THIS RETURNING WARM FRONT AND DRYLINE
HEATING WILL PROVE INADEQUATE FOR DEEP CONVECTION ACROSS TX DURING
THE AFTERNOON. HOWEVER...LATEST NAM MODEL IS PARTICULARLY
AGGRESSIVE IN DESTABILIZATION ATOP THE BOUNDARY LAYER DURING THE
OVERNIGHT HOURS JUST NORTH OF THE WARM FRONT. IN FACT FORECAST
SOUNDINGS EXHIBIT MUCAPE IN EXCESS OF 2000 J/KG IF LIFTING COOL
SECTOR PARCELS NEAR 850MB. WITH A LLJ EXPECTED TO INCREASE MARKEDLY
BY MORNING IT WOULD SEEM PLAUSIBLE THAT ROBUST ELEVATED CONVECTION
SHOULD GENERATE AHEAD OF SFC LOW ACROSS AR/MO BEFORE
SPREADING/DEVELOPING DOWNSTREAM INTO THE OH VALLEY BY SUNRISE. HAIL
IS THE PRIMARY SEVERE THREAT WITH THESE STORMS AS UPDRAFTS SHOULD
REMAIN PREDOMINANTLY ON THE COOL SIDE OF THE BOUNDARY AND ROOTED
WELL ABOVE THE SFC.


This post has been edited by Mid Tn. Man: Mar 1 2012, 07:25 AM

[Mid Tn. Man]

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1252 AM CST THU MAR 01 2012

VALID 021200Z - 031200Z

...THERE IS A MDT RISK OF SVR TSTMS PORTIONS
MS...AL...TN...KY...INDIANA...OH...

...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM ARKLAMISS REGION
ENEWD TO CAROLINAS AND NWD TO SWRN PA...INDIANA AND OZARKS...

...SYNOPSIS...
UPPER-AIR PATTERN TRANSITION IS UNDERWAY ATTM...WITH HEIGHT FALLS
ACROSS MUCH OF WRN CONUS IN ADVANCE OF SYNOPTIC SCALE TROUGH
DEVELOPMENT. RESULT THROUGH DAY-1 WILL BE BROADLY CYCLONIC FLOW
ACROSS MOST OF WRN CONUS...MOVING EWD TO CENTRAL CONUS DAY-2. BY
START OF PERIOD...EXPECT NRN-STREAM MID-UPPER CYCLONE LOCATED OVER
ND/MB BORDER REGION...AND BASAL 500-MB SHORTWAVE TROUGH OVER
4-CORNERS REGION. DOWNSTREAM FROM THAT PERTURBATION...LOWER-
AMPLITUDE SHORTWAVE SHOULD BE MOVING ENEWD ACROSS KS. VORTICITY
FIELDS WITH LATTER TWO SHORTWAVES SHOULD REMAIN WELL-CONNECTED...
EFFECTIVELY RESULTING IN POSITIVELY TILTED TROUGH FROM ERN IA/NRN IL
REGION TO ERN NM BY 3/00Z. BY 3/12Z...EXPECT MID-UPPER LOW OVER LH
OR ADJOINING PORTIONS ONT...WITH TROUGH SWWD OVER LOWEST SEGMENT OF
OH RIVER...OK...AND SRN NM.

AT SFC...COLD FRONT NOW IMPINGING ON SWRN APPALACHIANS/TN VALLEY/NRN
LA SHOULD MOVE BACK N AS WARM FRONT THIS PERIOD...WRN PORTION OF
WHICH WILL ATTACH WITH SFC FRONTAL-WAVE LOW OVER MO BY 2/12Z. LOW
WILL DEEPEN AND MOVE NEWD TOWARD SRN LOWER MI BY 3/00Z...THEN
OCCLUDE AND BECOME STACKED WITH MIDLEVEL VORTEX BY END OF PERIOD.
WARM FRONT SHOULD MOVE NEWD OVER MID-UPPER OH VALLEY AND CENTRAL
APPALACHIANS THROUGH PERIOD. COLD FRONT TRAILING SFC LOW SHOULD
START PERIOD OVER OZARKS...SERN OK AND W-CENTRAL TX. BY
3/00Z...COLD FRONT SHOULD REACH ERN INDIANA/WRN OH...SERN AR...AND
MIDDLE TX COASTAL PLAIN. BY 3/12Z...COLD FRONT SHOULD REACH
CENTRAL/ERN PA...WRN VA...NRN GA...AND SRN AL.

...OZARKS...LOWER MS/TN VALLEY AND AL TO OH VALLEY STATES...
SCATTERED ELEVATED TSTMS IN CLUSTERS MAY BE CARRY OVER FROM LATE
DAY-1 PERIOD OVER PORTIONS OZARKS...LOWER OH VALLEY AND MID-SOUTH
REGIONS...WITH FAVORABLE CAPE ALOFT AND DEEP-LAYER SHEAR FOR HAIL.
SOME OF THIS ACTIVITY MAY PERSIST LONG ENOUGH TO BECOME SFC-BASED BY
MIDDAY AND EARLY AFTERNOON IN INCREASINGLY FAVORABLE ENVIRONMENT FOR
SVR. OTHER SCATTERED-NUMEROUS TSTMS SHOULD DEVELOP ALONG/AHEAD OF
COLD FRONT. TSTMS SHOULD BE FAST-MOVING...COVERING LONG SWATHS WITH
THEIR SVR THREATS OVER ANY GIVEN PERIOD OF TIME.

AIR MASS AHEAD OF SFC COLD FRONT AND IN WAKE OF MORNING CONVECTION
SHOULD DESTABILIZE FAVORABLY AMIDST STG LOW-LEVEL WAA/MOISTURE
TRANSPORT. INTENSE DEEP-LAYER SHEAR AND LOW-LEVEL HODOGRAPHS WILL
SPREAD OVER MUCH OF WARM SECTOR...ALONG WITH SFC DEW POINTS
INCREASING FROM MID 50S OVER OH TO MID 60S OVER PORTIONS MS/AL. IN
TANDEM WITH DIURNAL SFC HEATING...THIS SHOULD SUPPORT MLCAPE 250-500
J/KG OVER PORTIONS OH/INDIANA...TO 1500-2000 J/KG RANGE OVER
PORTIONS TN/KY...THEN DECREASING SOMEWHAT FARTHER S DUE TO
INFLUENCES OF STABLE LAYERS ALOFT. DESPITE UNCERTAINTIES REGARDING
EXTENT/COVERAGE OF VARIOUS CONVECTIVE MODES THIS FAR OUT...EXPECT
WEAK CINH...BROADLY FAVORABLE CAPE/SHEAR PARAMETER SPACE...AND
RELATIVELY DENSE COVERAGE OF CONVECTION LIKELY TO IMPINGE ON THAT
SETTING. AS SUCH...NUMEROUS SVR WIND EVENTS ARE POSSIBLE ALONG WITH
POTENTIAL FOR STG TORNADOES FROM EITHER SUPERCELLS OR QLCS-VORTEX
MECHANISMS. AT LEAST A FEW WIND EVENTS AOA 65 KT AND
LONG-TRACK/SIGNIFICANT TORNADOES ARE POSSIBLE. THEREFORE...
SIGNIFICANT-SVR AREA IS BEING INTRODUCED...DRIVING CATEGORICAL MDT
RISK WHERE OVERLAID WITH RELATIVELY DENSE 45% TOTAL-SVR PROBABILITY.

...CAROLINAS...
INITIALLY SEPARATE SVR POTENTIAL MAY DEVELOP OVER THIS REGION DURING
AFTERNOON/EVENING...WHICH MAY CONNECT WITH ERN FRINGES OF LARGER SVR
AREA LATE IN PERIOD AS LATTER REGIME SHIFTS EWD. SRN BRANCH OF STG
MID-UPPER LEVEL FLOW WILL SPREAD OVER INCREASINGLY FAVORABLE
BOUNDARY-LAYER THETAE ASSOCIATED WITH RETREATING WARM FRONT.
PRIMARY UNCERTAINTIES ATTM RESIDE IN STRENGTH OF LOW-LEVEL
LIFT...AND THEREFORE CONVECTIVE COVERAGE. HOWEVER...DIURNAL
HEATING...PRESENCE OF REASONABLY WELL-DEFINED FRONTAL ZONE...AND
WEAK MLCINH SHOULD PERMIT WIDELY SCATTERED TO SCATTERED TSTMS TO
DEVELOP IN REGIME OF 60S F WARM-SECTOR DEW POINTS. ACCORDINGLY
ADJUSTED FCST SOUNDINGS SUGGEST 1000-1500 J/KG LATE-AFTERNOON MLCAPE
POSSIBLE...JUXTAPOSED WITH 50-60 KT EFFECTIVE SHEAR MAGNITUDES.
MAIN THREAT MAY BE DAMAGING WIND...WITH ISOLATED HAIL ALSO EXPECTED.
FCST HODOGRAPHS ALSO ARE FAVORABLE FOR SUPERCELL/TORNADO RISK...MAIN
QUESTIONS BEING COVERAGE/DURATION OF FAVORABLE STORM MODES.

[Mid Tn. Man]

SE people should be alert,dangerous storm is brewing.NAM got even worse for us here in M/Tn on the 12z

[NorthMSWatcher]

What is the Torcon rate for North Mississippi on Friday? Where can I find it? All help is appreciated. I am in Oxford, MS.

SE people should be alert,dangerous storm is brewing.NAM got even worse for us here in M/Tn on the 12z

[jdrenken]

What is the Torcon rate for North Mississippi on Friday? Where can I find it? All help is appreciated. I am in Oxford, MS.

Here.

MS north half - 6

[Superstorm93]

Oh god...

Sorry I passed out from laughter.

The setup and aftermath on Friday for the Ohio and Tennessee valleys could be similar to the weather pattern during and following the 1974 Super Outbreak.

Spanning April 3-4, 1974, a swarm of tornadoes tore through areas from Illinois and southern Michigan to northern Alabama and Georgia.

The outbreak produced 148 confirmed tornadoes, six of which were F-5 intensity. The most powerful of these storms slammed into Xenia, Ohio.

Every weather pattern no matter how similar always has its differences, and this outbreak will have its own characteristics.

However, according to Severe Weather Expert Henry Margusity, "In the case of the end of this week and back in early April of 1974, it appears strong upper-level winds and cool air approaching from the west could hit a zone of advancing warm, moist air in just the right manner to produce monsters of thunderstorms."

[31B militaryPoli...]

Oh god...

Sorry I passed out from laughter.

Ummm... where did you find this lol?

[31B militaryPoli...]

Low level shear is pretty impressive with 0-1KM shear 40-50Kts; helicity 200-300 M2/S2 range.