April 28th-29th Severe Threat

[Windspeed]

A significant severe weather threat is growing for portions of the Mississippi and Tennessee Valley regions on Monday and Tuesday, stretching from the Gulf Coast as far north as southern Illinois. The SPC has issued D6 risk to cover those areas and there is potential for a D7 risk area to be extended further east into the plateau and southern and central Appalachians. The atmospheric setup will be conducive for some discrete supercells capable of producing heavy rain, large hail, damaging winds and tornadoes. Areas further east may have less of a tornado threat; however, a strong line may evolve with damaging straightline winds as the system advances further eastward on Tuesday. Monday afternoon and evening has the potential to be a real tornado threat for Dixie Alley and I'm sure we'll all be watching closely to see how this continues to evolve.

 

[Indystorm]

James Spann has mentioned that the Birmingham NWS radio is down and will be so for much of next week.  Bad timing.  Hope people rely upon multiple warning sources.  The oncoming trough and large warm sector hold the potential for a significant multi day event from the Plains to TN Valley and Dixie.

[jaxjagman]

 

 

DAY 4-8 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0338 AM CDT THU APR 24 2014

   VALID 271200Z - 021200Z

   ...DISCUSSION...
   ...SIGNIFICANT MULTI-DAY SEVERE EVENT EXPECTED ACROSS PORTIONS OF
   THE CENTRAL/SOUTHERN PLAINS AND MS VALLEY SUNDAY...AND MS
   VALLEY/CNTRL GULF STATES ON MONDAY...STRONG TORNADOES ARE
   POSSIBLE...

   BOTH THE ECMWF/GFS ARE IN GENERAL AGREEMENT REGARDING THE EVOLUTION
   OF UPPER LOW AS IT PROGRESSES INTO THE PLAINS SUNDAY...THEN INTO THE
   MS VALLEY MONDAY.  AFTER INITIAL SPEED MAX EJECTS INTO THE CNTRL
   PLAINS SUNDAY SUBSTANTIAL MID-LEVEL FLOW DEVELOPS WITHIN THE BASE OF
   THE TROUGH OVER TX AND SPREADS ACROSS THE LOWER MS VALLEY INTO THE
   NCNTRL GULF STATES/TN VALLEY.  ECMWF IS MORE SUPPRESSED WITH THIS
   STRONGER FLOW THAN THE GFS BUT THE IDEA THAT STRONG FLOW SHOULD
   OVERSPREAD A BUOYANT AIRMASS BOTH DAYS REMAINS.

   MODELS CONTINUE TO SURGE THE DRYLINE ACROSS THE PLAINS EARLY IN THE
   PERIOD WITH BOTH AGREEING THAT SIGNIFICANT BOUNDARY LAYER DRYING
   WILL SPREAD EAST OF I-35 CORRIDOR FAIRLY EARLY SUNDAY.  GIVEN THE
   MID-LEVEL JET THAT EJECTS INTO THE CNTRL PLAINS EARLY THIS MAY
   TRANSPIRE AND SEVERE THUNDERSTORMS SHOULD EVOLVE FROM SERN
   NEB...ACROSS ERN KS/OK INTO NERN TX BEFORE SPREADING INTO WRN
   MO/AR/NWRN LA.

   DEEP SFC CYCLONE WILL GRADUALLY SHIFT EAST ACROSS THE CNTRL PLAINS
   AND ARCING FRONTAL POSITION AT 12Z MONDAY SHOULD EXTEND ALONG/NEAR
   THE KS/MO BORDER...SWD INTO SERN TX.  SEVERE THUNDERSTORMS SHOULD
   REDEVELOP ACROSS THE WARM SECTOR AS 80KT 500MB FLOW EJECTS ACROSS
   THE LOWER MS VALLEY INTO WRN TN DURING THE DAY.  A FEW STRONG
   TORNADOES MAY BE NOTED WITH SUPERCELLS THAT DEVELOP ALONG/AHEAD OF
   DRYLINE/PACIFIC FRONT BOTH SUNDAY AND MONDAY.

   ..DARROW.. 04/24/2014

 

[Indystorm]

Birmingham NWS says it is expediting repairs to its transmitter so that wx radios can be operational for Monday.  Good News!

[BamaChemE]

Anyone care to share what the latest Euro run is saying about Monday?

[andyhb]

Anyone care to share what the latest Euro run is saying about Monday?

 

It's ugly, for Monday and Tuesday,

[jaxjagman]

Multi day event like Andy said,even on todays 12z on the Euro for the Eastern part of the Valley on 12z Wed it shows the 850mb winds @ 55kts,KI 33-34,700-500 Lapse at 6 with dp's 60-65,capes around 500-1k

[jaxjagman]

AS FOR SUN THRU THE MID PORTION OF NEXT WEEK...AGAIN...AN ACTIVE WX
PATTERN LOOKS TO BE IN STORE FOR THE MID STATE BY SUN INTO AT LEAST
MON NIGHT...WITH THE MID STATE BEING IN A BROAD WARM SECTOR OF A
DEVELOPING STRONG FRONTAL SYSTEM BY THE EARLY MORNING HRS ON
MON...WITH EXPECTED PASSAGE ACROSS THE MID STATE MON NIGHT INTO TUE.
WOULD NOT BE SURPRISED AS THE WARM FRONT MOVES N ACROSS THE MID STATE
ON SUN...FOR SCT SHWRS AND TSTMS TO DEVELOP AS THE DAY
PROGRESSES...WITH SOME STRONG TSTMS...TO POSSIBLY EVEN SVR TSTMS...ACROSS
THE MID STATE DURING THE LATE AFTERNOON TO EVENING HRS. SPC CONTINUES
TO PLACE MOST OF THE MID STATE W OF THE PLATEAU REGION IN A DAY 5 OUTLOOK
FOR MON AND MON NIGHT...AS FRONT PUSHES INTO THE MID STATE
DURING THE EVENING HRS ON MON. MULTIPLE ATM INSTABILITY PARAMETERS
RATHER HIGH ATM MOISTURE CONTENT...ALONG WITH DIURNAL AND FRONTAL LIFTING
MECHANISM ARE ALL IN PLAY. ALONG WITH DEWPOINTS POSSIBLY INTO THE MID TO
UPPER 60S ACROSS THE MID STATE DURING THE AFTERNOON HRS ON MON...WITH
DEWPOINTS IN THE 60S ON MON NIGHT TOO WITH STRENGTHENING LOW LEVEL JET
SUPPORT...STILL EXPECTING THE MAIN BRUNT OF THE SVR TSTM POTENTIAL TO BE
DURING THE MON NIGHT TIME FRAME ASSOCIATED WITH THE FRONTAL PASSAGE.
HOWEVER...EXPECTING NUMEROUS SHWRS AND TSTMS TO DEVELOP AS THE DAY
PROGRESSES ON MON WITH AT LEAST ISO STRONG TO SVR TSTMS POSSIBLE.
ANY WAY YOU SLICE IT...THE POTENTIAL IS THERE FOR AN OUTBREAK OF
ORGANIZED SVR WX ACROSS THE MID STATE DURING THIS MON THRU MON NIGHT
TIME FRAME...BUT IT STILL LOOKS LIKE THE OVERALL BEST POTENTIAL FOR
SVR WX WILL BE W AND SW OF THE MID STATE DURING THIS TIME PERIOD. ALSO
WOULD NOT BE SURPRISED THAT HEAVY RAINFALL OCCURS DURING THIS TIME PERIOD
TOO...WITH HIGHEST AMOUNTS ACROSS WRN PORTIONS OF THE MID STATE. MODELS
CONTINUE TO COME MORE AND MORE IN LINE IN AGREEMENT WITH THE OVERALL WX
PATTERN...WITH PROGRESSIVE LOW LEVEL JET DYNAMICS CONTINUING THRU AT LEST
TUE NIGHT AS A STRONG SFC/UPPER LEVEL LOW PRESSURE SYSTEM MOVES FROM THE
NRN PLAINS INTO THE UPPER MS RIVER VALLEY/W GREAT LAKES REGION BY WED
MORNING ALSO. WITH THIS EVENT THOUGH BEING STILL SEVERAL DAYS AWAY...WILL
BE GOING CLOSE TO PREVIOUS FORECAST REASONING OVER THIS TIME PERIOD AS
FURTHER AND FUTURE MODEL RUN DETAILS AND CLARIFICATIONS NEEDED BEFORE
COMPLETE CERTAINTY INTO SPECIFICS OF EVENT CAN BE DETERMINED...WITH ACTUAL
DEVELOPMENT OF SMALL SCALE TIME FEATURES KEY IN WHAT OVERALL AMOUNT
OF SVR WX WE DO EXPERIENCE ACROSS THE MID STATE DURING THIS TIME
PERIOD. TEMPS LATE WEEKEND AND INTO THE FIRST PART OF NEXT WEEK WILL
CONTINUE ABOVE SEASONABLE NORMAL VALUES FOR HIGHS THRU AT LEAST WED.
&&

 

http://forecast.weather.gov/product.php?site=NWS&issuedby=OHX&product=AFD&format=CI&version=1&glossary=1

[jaxjagman]

UNDAY THROUGH NEXT WEDNESDAY...

FORECAST THINKING IS GENERALLY THE SAME REGARDING THE POTENT SET-
UP FOR SEVERE WEATHER AND HEAVY RAIN INDICATED BY GLOBAL MODEL
GUIDANCE FOR EARLY NEXT WEEK...PARTICULARLY FROM LATE SUNDAY THROUGH
MONDAY NIGHT...AND PERHAPS THROUGH TUESDAY INTO TUESDAY NIGHT. ALL
MODES OF SEVERE WEATHER INCLUDING THE POTENTIAL FOR STRONG TORNADOES
WILL BE POSSIBLE. SIGNIFICANT FLOODING COULD DEVELOP IF MULTIPLE
ROUNDS OF STORMS MATERIALIZE.

DRY WEATHER WILL CONTINUE THROUGH SATURDAY NIGHT OVER THE ARKLAMISS...
BUT DRAMATIC CHANGES ARE EXPECTED STARTING SUNDAY AFTERNOON AND GOING
THROUGH SUNDAY NIGHT AS A POWERFUL DEEPENING CYCLONE TRAVERSES THE
PLAINS STATES AND BRINGS RAPID PRESSURE FALLS TO THE LOWER MS VALLEY
REGION. A STRENGTHENING LOW LEVEL JET JUXTAPOSED BY STEEP MID LEVEL
LAPSE RATES WILL DRAW RICH GULF MOISTURE NORTHWARD (SFC DEWPOINTS
APPROACHING 70 F) AND INCREASE LOW LEVEL SHEAR AND TORNADO POTENTIAL
BY SUNDAY EVENING OVER THE DELTA REGION AS SFC- BASED THUNDERSTORMS
BREAK OUT. THE FIRST ROUND OF STORMS MAY ORGANIZE INTO A MESOSCALE
CONVECTIVE SYSTEM TAPPING INTO VERY MOIST AIR WITH PRECIPITABLE WATER
~ 1.75 INCHES. THIS MCS COULD PUSH ACROSS MUCH OF THE ARKLAMISS
OVERNIGHT BEFORE WEAKENING SOME AS IT OUTRUNS BETTER UPPER LEVEL
SUPPORT. HOWEVER...EXPECT RE-NEWED SEVERE THUNDERSTORM ACTIVITY
MONDAY AS THE NOSE OF POWERFUL PACIFIC JET ENERGY ROUNDS THE BASE OF
THE DEEP CENTRAL CONUS TROUGH AND ENHANCES WIND SHEAR/LIFT AND THE
SEVERE WEATHER RISK OVER THE FORECAST AREA. MIXED LAYER CAPE > 3000
J/KG COULD HELP MAY FOR A VOLATILE SET-UP WITH THIS SYNOPTIC PATTERN.

CIPS ANALOGS ARE SHOWING VERY SIGNIFICANT EVENTS FOR COMPARISON TO
THIS SET-UP ADDING MORE CONFIDENCE THAT SIGNIFICANT SEVERE WEATHER
AND FLOODING WILL BE POSSIBLE...ESPECIALLY IF A SLOW-MOVING
CONVECTIVE SYSTEM SETS UP MONDAY NIGHT AS GUIDANCE SUGGESTS. ANOTHER
CONCERN IS THE POSSIBILITY FOR THE CYCLONIC REGIME TO STALL OVER THE
CENTRAL CONUS FOR A LONGER PERIOD INTO TUESDAY...ALLOWING ANOTHER LOBE
OF SHORTWAVE ENERGY TO MOVE ACROSS THE AREA AND BACK FLOW
SUFFICIENTLY FOR REGENERATION OF STORMS. BEYOND TUESDAY NIGHT...
EXPECT DRIER AND COOLER AIR TO FINALLY MOVE INTO THE REGION. /EC/

http://forecast.weather.gov/product.php?site=NWS&issuedby=JAN&product=AFD&format=CI&version=1&glossary=1

[jaxjagman]

TEMPERATURES WILL REALLY GO UP OVER THE WEEKEND. THE WARM FRONT WILL
WASH OUT AS A NEW WARM FRONT BECOMES ESTABLISHED ACROSS THE OHIO
RIVER VALLEY. SOUTHERLY FLOW AT THE SURFACE AND HIGHER UPPER LEVEL
HEIGHTS WILL PUSH TEMPERATURES UP INTO THE MID 80S EACH AFTERNOON.
DUE TO THE STRONG RIDGE...EXPECT A CAP WILL BE IN PLACE AND NOT
EXPECTING ANY CONVECTION TO FORM SATURDAY AFTERNOON. THE RIDGE
BEGINS TO BREAKDOWN LATE SUNDAY AS A POTENT UPPER LEVEL LOW SPINS
ACROSS THE CENTRAL PLAINS. A COUPLE OF THE MODELS SUGGEST A MCS
WILL FORM ALONG THE MISSISSIPPI RIVER AND PROGRESS TO THE EAST AND
DIE ALONG THE AL/MS STATE LINE. DUE TO THIS...CONTINUED HIGH CHANCES
POPS ACROSS THE NORTHWEST. JUST BEYOND THIS TIMEFRAME IS WHEN THINGS
BEGIN TO GET REALLY INTERESTING ACROSS CENTRAL ALABAMA

WITH EACH MODEL RUN...THE WEATHER SITUATION LOOKS MORE AND MORE
CONCERNING FOR MONDAY AFTERNOON INTO POSSIBILITY WEDNESDAY MORNING.
THE BIG WEATHER STORY WILL REMAIN TO BE THE CLOSED UPPER LEVEL LOW
OVER THE CENTRAL PLAINS EARLY NEXT WEEK. MULTIPLE SHORTWAVE TROUGHS
WILL ROTATE AROUND THIS CLOSED LOW PROVIDING CENTRAL ALABAMA WITH
MULTIPLE SHOTS FOR SEVERE WEATHER. UPPER LEVEL HEIGHT FALLS BEGIN TO
TAKE PLACE MONDAY AFTERNOON AS THE FIRST WAVE ROTATES AROUND THE
CLOSED LOW. TEMPERATURES WILL WARM INTO THE 80S ON MONDAY WITH
SBCAPE VALUES REACHING 1000-2000 J/KG WITH THE HIGHEST INSTABILITY
JUST TO THE WEST OF THE FORECAST AREA. THE FIRST WAVE IS NOT
EXPECTED TO ARRIVE UNTIL LATER IN THE DAY AND INTO THE OVERNIGHT
HOURS...THEREFORE...INSTABILITY VALUES WILL DECREASE SOME BUT MODELS
ARE STILL INDICATING AROUND 1000 J/KG OF SBCAPE DURING THE OVERNIGHT
HOURS. THE LOW LEVEL JET WILL INTENSIFY DURING THE OVERNIGHT HOURS
TO AROUND 45-55 KTS THIS WILL BE SUFFICIENT ENOUGH TO RAISE THE 0-1
KM SRH TO AROUND 200-300 M2/S2. THE DEEP LAYER SHEAR WILL BE ON THE
ORDER OF 40-50 KTS AND SHOULD BE ENOUGH TO MAINTAIN UPDRAFT
INTENSITY. ALL MODES OF SEVERE WEATHER WILL BE POSSIBLE BASED ON THE
CURRENT SEVERE WEATHER PARAMETERS. THIS FIRST ROUND WILL BE WELL
AHEAD OF THE SURFACE FRONT AND ANOTHER ROUND OF SEVERE WEATHER IS
FORECAST BY BOTH THE GFS AND ECMWF. MODELS INDICATE THERE COULD BE A
BRIEF BREAK TUESDAY MORNING AS THE LOW LEVEL JET LIFTS OUT AND THE
FIRST SHORTWAVE TROUGH LIFTS OFF TO NORTHEAST. THE SECOND ROUND IS
EXPECTED TUESDAY AFTERNOON INTO TUESDAY NIGHT AS ANOTHER SHORTWAVE
TROUGH ROTATES THROUGH THE BROAD CLOSED LOW. THE SEVERE WEATHER
PARAMETERS WILL BE VERY SIMILAR. THE ONLY DIFFERENCE IS THAT THE
DEEP LAYER 0-6 KM SHEAR IS FORECAST TO BE A BIT STRONGER WITH THE
SECOND ROUND. AGAIN...ALL MODES OF SEVERE WEATHER WILL BE POSSIBLE
WITH THIS SECOND ROUND AS WELL. MODELS HAVE BEEN FAIRLY CONSISTENT
AND CONFIDENCE CONTINUES TO INCREASE IN THE SEVERE WEATHER POTENTIAL
FOR MONDAY INTO TUESDAY. THERE ARE STILL SEVERAL QUESTIONS THAT
REMAIN REGARDING THE POTENTIAL EVENT. HOW WILL THE FIRST ROUND
AFFECT THE SECOND? HOW WILL THE TIMING WORK OUT? WILL BOTH ROUNDS BE
A NOCTURNAL EVENT OR HAPPEN DURING THE DAY? AT THIS TIME...IT LOOKS
LIKE BOTH ROUNDS COULD BE DURING THE OVERNIGHT HOURS. PLEASE PREPARE
AND BE READY FOR THIS EVENT. A TEMPORARY SOLUTION IS IN PLACE FOR
THE NWR TRANSMITTER IN BIRMINGHAM PLEASE SEE THE LATEST PNS FOR THE
MOST UP TO DATE INFORMATION. PLEASE HAVE YOUR SEVERE WEATHER PLAN
READY AS WE HEAD INTO EARLY NEXT WEEK.

05/MA

http://forecast.weather.gov/product.php?site=NWS&issuedby=BMX&product=AFD&format=CI&version=1&glossary=1

[jaxjagman]

[jaxjagman]

[jaxjagman]

 

 

DAY 4-8 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0351 AM CDT FRI APR 25 2014

   VALID 281200Z - 031200Z

   ...DISCUSSION...
   ...MULTI-DAY SEVERE EPISODE SHOULD CONTINUE INTO AT LEAST TUESDAY
   FROM THE OH VALLEY TO THE CNTRL GULF COAST. POTENTIAL EXISTS FOR A
   SEVERE WEATHER OUTBREAK INCLUDING STRONG TORNADOES...

   ACTIVE SEVERE WEATHER PATTERN WILL PERSIST WITH A BROAD UPPER-LEVEL
   TROUGH CENTERED OVER THE CNTRL CONUS. ECMWF/GFS/UKMET/CMC ARE RATHER
   CONSISTENT WITH THE EVOLUTION OF INTENSE MID-LEVEL SPEED MAXIMA
   ROTATING THROUGH THE BASE OF THE TROUGH INTO D5/TUE. THESE WINDS
   WILL OVERSPREAD PARTS OF A BROAD WARM/MOIST SECTOR CHARACTERIZED BY
   60S SURFACE DEW POINTS. DESPITE MULTIPLE DAYS OF EXTENSIVE WARM
   SECTOR CONVECTION...DIURNAL HEATING COUPLED WITH W/SWLYS IN THE
   MID-LEVELS SHOULD RECHARGE/STEEPEN LAPSE RATES...POTENTIALLY
   YIELDING MODERATE TO STRONG INSTABILITY EACH AFTERNOON. OF THE TWO
   DAYS HIGHLIGHTED...D5/TUE APPEARS TO HAVE SLIGHTLY GREATER OUTBREAK
   POTENTIAL WITH A 90+ KT 500-MB JET EJECTING OUT OF THE BASE OF THE
   TROUGH.

[tnweathernut]

It certainly looks like early next week could be ugly for a widespread area in the southeast and TN Valley regions.

Severe weather isn't my specialty, but it doesn't take a rocket scientist to see the potential. Thanks to those keeping us updated.

Sent from my iPhone using Tapatalk

[nrgjeff]

Monday and esp Tuesday looking more ominous for the Mid South and parts of the Deep South. Models have started to consolidate the southern system. Jet stream still shown coming out of Texas into Dixie. Now instead of a surface low drifting around the Upper Midwest, low press is shown developing in the Mississippi Valley. DL had looked more diffuse on 12Z Thu guidance. Now a quasi-DL feature is shown once again sweeping into the South. It'll be plenty warm and humid in the warm sector. Wind fields at all levels are impressive. Hodographs, yeah a little early, would be robust if these models are right.

 

Let's agree to something, esp if this thread gets pinned, regarding NWS discussions. We can all read them. Let's not post them here except for short excerpts. Include our own thoughts. What do you think? We'll have a lot of visitors from other regions. Let's make our new sub-forum shine!

[TropicalAnalystwx13]

Ominous but well-warranted wording from NWS Birmingham regarding next Monday and Tuesday. Deep-layer shear of 50-60 knots and 0-1km SRH of >200 m2/s2 will be more than favorable for significant tornadoes.

 

BASED ON THE LATEST MODEL
GUIDANCE A FEW STRONG TO VIOLENT TORNADOES CANNOT BE RULED OUT
ACROSS THE FORECAST AREA. NOW IS THE TIME TO PREPARE FOR THE SEVERE
WEATHER THREAT EARLY NEXT WEEK. PLEASE PREPARE TO TAKE YOUR SEVERE
WEATHER PRECAUTIONS EARLY NEXT WEEK.

[Hoosier]

As this looks to be a higher end/widespread threat, there's now a thread in the main forum for this event.

 

http://www.americanwx.com/bb/index.php/topic/43501-april-26th-29th-significant-severe-potential/

[Carvers Gap]

Any updates specific to the TN Valley?

[jaxjagman]

Nothing much to add,the RAP is showing some possible big storm to the west valley later today with some 850mb winds 50+kts

[jaxjagman]

 

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0751 AM CDT SUN APR 27 2014

   VALID 271300Z - 281200Z

   ...THERE IS A MDT RISK OF SVR TSTMS OVER FAR ERN PARTS OF
   KS/OK...NERN TX...AR...WRN/CNTRL/SRN MO...NWRN MS AND WRN TN...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY TO ERN
   TX AND THE LOWER MS VALLEY...

   ...SUMMARY...
   WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF TORNADOES...VERY LARGE
   HAIL AND DAMAGING WINDS ARE LIKELY FROM THE MIDDLE AND LOWER
   MISSOURI VALLEY SOUTH THROUGH THE OZARKS INTO LOWER MISSISSIPPI
   VALLEY THIS AFTERNOON INTO TONIGHT. THE GREATEST RISK FOR A FEW
   INTENSE TORNADOES WILL EXIST ACROSS MUCH OF ARKANSAS PERHAPS INTO
   WESTERN AND CENTRAL MISSOURI THIS AFTERNOON INTO TONIGHT.

   ...SYNOPSIS...

   A POWERFUL SHORT-WAVE TROUGH AND ASSOCIATED 70-80 KT MIDLEVEL JET
   STREAK WILL TRANSLATE FROM THE CNTRL/SRN HIGH PLAINS INTO THE UPPER
   MIDWEST WITH THE SYSTEM CLOSING OFF AN UPPER LOW OVER THE CNTRL
   PLAINS. ON THE HEELS OF THE INITIAL SHORT-WAVE TROUGH...A CHANNELED
   VORTICITY MAXIMUM AND ATTENDANT 70+ KT JET STREAK AT 500 MB WILL
   PROGRESS THROUGH THE SRN PLAINS INTO THE OZARK PLATEAU BY TONIGHT.
   IN RESPONSE TO THIS UPPER-AIR PATTERN EVOLUTION...A 40-50+ KT SLY
   LLJ WILL MIGRATE FROM ERN PARTS OF THE GREAT PLAINS INTO MS
   VALLEY...ENHANCING THE POLEWARD FLUX OF HEAT AND MOISTURE THROUGH
   THE WARM SECTOR OF THE SYNOPTIC CYCLONE. 

   AT THE SURFACE...A LEE CYCLONE OVER SWRN NEB WILL GRADUALLY FILL AS
   IT SLOWLY DEVELOPS ENEWD INTO ERN NEB BY 28/12Z. A TRAILING PACIFIC
   FRONT WILL SURGE EWD THROUGH THE CNTRL PLAINS INTO OZARKS/OZARK
   PLATEAU WITH THE SRN EXTENSION OF THE FRONT MOVING MORE SLOWLY EWD
   THROUGH CNTRL INTO ERN TX. MEANWHILE...A WARM FRONT WILL STEADILY
   MOVE NWD THROUGH THE LOWER/MID MO AND MID MS VALLEYS.

   ...SRN PLAINS INTO THE LOWER MS VALLEY THIS MORNING THROUGH
   TONIGHT...

   TSTMS HAVE RECENTLY DEVELOPED ALONG AND JUST AHEAD OF THE PACIFIC
   FRONT OVER OK/N TX ALONG THE SRN FRINGE OF STRONGER HEIGHT
   FALLS/DCVA ATTENDANT TO THE SHORT-WAVE PROGRESSING NEWD INTO THE
   CNTRL PLAINS. THESE STORMS ARE LIKELY SLIGHTLY ELEVATED AND ROOTED
   WITHIN A MOIST WARM CONVEYOR BELT AIR STREAM WHICH COINCIDES WITH
   STEEP MIDLEVEL LAPSES AND MUCAPE OF 2000-2500 J/KG. AREA VAD DATA
   INDICATE A VEER-BACK SIGNATURE WITH HEIGHT WHICH SHOULD YIELD
   COMPLEX STORM MODES CAPABLE OF MAINLY LARGE HAIL AND LOCALLY
   DAMAGING WINDS AS ACTIVITY SHIFTS NEWD THIS MORNING.

   A SUBSET OF THE ONGOING STORMS WILL LIKELY BECOME SURFACE-BASED BY
   LATE MORNING INTO AFTERNOON OVER ERN OK INTO NERN TX WITH OTHER IN
   SITU STORM DEVELOPMENT ALONG THE FRONT. ADDITIONAL TSTMS ARE
   ANTICIPATED BY AFTERNOON AHEAD OF THE FRONT FROM THE ARKLATEX NEWD
   ACROSS AR...IN THE WAKE OF THE MORNING ELEVATED STORMS. BOTH THESE
   REGIMES WILL BE ENCOURAGED BY THE ARRIVAL OF THE NEXT MIDLEVEL JET
   STREAK PROPAGATING THROUGH THE RED RIVER VALLEY.

   THE COMBINATION OF MODERATE INSTABILITY AND RELATIVELY STRONG
   VERTICAL SHEAR WILL PROMOTE A MIXTURE OF SUPERCELL AND BOWING
   STRUCTURES CAPABLE OF TORNADOES...VERY LARGE HAIL AND DAMAGING
   WINDS. THE MOST FAVORABLE ENVIRONMENT FOR LONG-LIVED SUPERCELLS AND
   MULTIPLE INTENSE TORNADOES WILL LIKELY MATERIALIZE OVER AR TOWARD
   THE DELTA REGION OF NWRN MS LATER THIS AFTERNOON INTO TONIGHT.
   HERE...MLCAPE OF 2000-2500 J/KG WILL ALIGN WITH EFFECTIVE SRH OF
   250-350 M2/S2 AND 50-60 KT OF DEEP-LAYER SHEAR TO CREATE A VERY
   FAVORABLE ENVIRONMENT FOR UPDRAFT ROTATION. AN UPGRADE TO A
   CATEGORICAL HIGH RISK REMAINS POSSIBLE OVER THIS AREA LATER TODAY.

   ...NEB/KS EWD INTO MID MS VALLEY LATE THIS MORNING INTO TONIGHT...

   ELEVATED TSTMS HAVE GRADUALLY INCREASED IN COVERAGE EARLY THIS
   MORNING OVER THE CNTRL PLAINS ALONG THE LEADING EDGE OF HEIGHT FALLS
   ATTENDANT TO THE HIGH PLAINS SHORT-WAVE TROUGH...AND ROOTED WITHIN A
   BELT OF ISENTROPIC ASCENT ALONG THE NOCTURNAL LLJ. THIS ACTIVITY MAY
   CONTINUE TO INCREASE IN AREAL COVERAGE THIS MORNING WHILE MOVING
   NEWD INTO THE MID AND LOWER MO VALLEY. LARGE HAIL AND LOCALLY
   DAMAGING WIND GUSTS WILL BE THE PRIMARY HAZARDS WITH THESE STORMS.

   UNCERTAINTY IN DEGREE OF AFTERNOON DESTABILIZATION HAS INCREASED
   OVER THE LAST COUPLE OF HOURS OWING TO THE GROWING EXTENT OF
   ELEVATED TSTMS. WHERE BREAKS IN THE CLOUDS CAN OCCUR...CONTINUED
   BOUNDARY LAYER MOISTENING COUPLED WITH STRONG COOLING ALOFT WILL
   PROMOTE MLCAPE APPROACHING 1000-2000 J/KG. WHEN COUPLED WITH
   VERTICALLY VEERING WIND PROFILES AND 40-50 KT OF DEEP-LAYER
   SHEAR...THE ENVIRONMENT WILL BE SUPPORTIVE OF A MIXTURE OF BOWING
   AND SUPERCELL STRUCTURES CAPABLE OF TORNADOES /SOME POSSIBLY
   STRONG/...VERY LARGE HAIL AND DAMAGING WINDS. THE POTENTIAL FOR
   ISOLATED TORNADOES WILL EXIST AS FAR W/SW AS WRN NEB/NERN CO/NWRN KS
   INVOF THE DEEP-LAYER CYCLONE WHERE STEEP LAPSE RATES WILL COINCIDE
   WITH HIGH AMBIENT VERTICAL VORTICITY.

   BY THIS EVENING INTO TONIGHT...TSTMS MAY CONSOLIDATE INTO CLUSTERS
   OR A QLCS WITH THE RISK FOR PRIMARILY DAMAGING WINDS AND HAIL
   SPREADING EWD INTO THE MID MS VALLEY.

   ..MEAD/MOSIER.. 04/27/2014

 

 

[jaxjagman]

 

DAY 2 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT SUN APR 27 2014

   VALID 281200Z - 291200Z

   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF MS...NRN
   AL...TN...NERN LA...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM IA AND IL SWD ACROSS THE
   OH...TN...THE MID/LOWER MS VALLEY EWD TO THE WRN CAROLINAS...

   ...SUMMARY...
   WIDESPREAD SEVERE STORMS INCLUDING STRONG TORNADOES...DAMAGING WINDS
   AND VERY LARGE HAIL APPEAR LIKELY MONDAY AND MONDAY NIGHT ACROSS
   MUCH OF MISSISSIPPI...NORTHERN ALABAMA...TENNESSEE...SOUTHERN
   KENTUCKY...AND NORTHEASTERN LOUISIANA.

   ...SYNOPSIS...
   LOW-PRESSURE WILL BECOME VERTICALLY STACKED OVER ERN NEB AND IA
   DURING THE DAY WITH LEADING JET MAX DEVELOPING NEWD FROM THE
   ARKLATEX INTO THE LOWER OH VALLEY. AN OCCLUDED FRONT WILL EXTEND EWD
   FROM THE LOW ACROSS IA AND NRN IL...WITH WARM FRONT LIFTING NWD
   ACROSS INDIANA AND OHIO. A COLD FRONT WILL EXTEND SWD FROM THE
   LOW...ARCING RAPIDLY NEWD ACROSS THE MID MO RIVER VALLEY DURING THE
   DAY AND BECOMING STATIONARY ACROSS THE LOWER MS RIVER VALLEY BY LATE
   AFTERNOON. AN UNSTABLE AND MOIST ENVIRONMENT WILL EXIST AHEAD OF THE
   COLD FRONT WITH SHEAR PROFILES FAVORABLE FOR SEVERE THUNDERSTORMS
   ACROSS A LARGE AREA FROM IA TO THE CNTRL GULF COAST.

   TO THE E...A FRONT WILL GRADUALLY RETREAT NWD ACROSS NC...ALLOWING
   FOR DESTABILIZATION AND A THREAT OF ISOLATED SEVERE STORMS THERE.

   ...LOWER MS VALLEY EWD INTO NRN AL AND MIDDLE TN...
   WHILE THE PREVIOUS DAYS CONVECTION WILL LIKELY PLAY A ROLE IN
   DELINEATING THE PRECISE THREAT CORRIDOR...A SW-NE ORIENTED ZONE OF
   TRAINING SEVERE THUNDERSTORMS IS LIKELY FROM NERN LA ACROSS MS AND
   INTO NRN AL AND MIDDLE TN. THE STORMS WILL EITHER BE TIED TO THE
   COLD FRONT...OR AN OUTFLOW BOUNDARY WHICH COULD SPREAD OUT AHEAD OF
   THE MAIN SLOW MOVING FRONT. REGARDLESS...A VERY MOIST AND UNSTABLE
   AIR MASS WILL RESIDE AHEAD OF THE COLD FRONT...WITH SHEAR PROFILES
   QUITE FAVORABLE FOR SUPERCELLS AND TORNADOES. A LONG UPDRAFT
   RESIDENCE TIME IN THE UNSTABLE AND HIGHLY SHEARED ENVIRONMENT...AS
   WELL AS RELATIVELY STEEP MIDLEVEL LAPSE RATES SUGGEST STRONG
   TORNADOES WILL BE POSSIBLE. VERY LARGE HAIL WILL ALSO OCCUR AS WELL
   AS POTENTIAL FLOODING. THE MOST SIGNIFICANT TORNADO THREAT IS
   EXPECTED ACROSS MS.

   ...CNTRL AND NRN IL...FAR ERN IA AND NWRN IND...
   STRONG HEIGHT FALLS AND COOLING ALOFT WITH THE LEFT-EXIT REGION OF
   THE MIDLEVEL JET WILL OVERSPREAD THE WARM SECTOR...RESULTING IN
   RAPID DESTABILIZATION. WITH LITTLE CAPPING...A BROKEN ARC OF STORMS
   IS EXPECTED TO FORM BY EARLY AFTERNOON ALONG THE COLD FRONT. LARGE
   HAIL WILL BE LIKELY ALONG WITH A FEW TORNADOES.

   ...NRN SC INTO WRN AND CNTRL NC...
   AN E-W ORIENTED BOUNDARY WILL GRADUALLY MOVE NWD ACROSS NC...WITH
   MID 60S DEWPOINTS TO THE S. DAYTIME HEATING WILL ALLOW FOR
   DESTABILIZATION WITH AROUND 1000-1500 MLCAPE DEVELOPING BY
   AFTERNOON. WHILE SHORTWAVE RIDGING WILL EXIST MUCH OF THE
   DAY...COOLING ALOFT AND INCREASING SHEAR PROFILES WILL SPREAD INTO
   FAR WRN NC AND SC LATE IN THE DAY...RESULTING IN A FAVORABLE
   SUPERCELL ENVIRONMENT. HAIL WILL BE A DISTINCT THREAT WITH THE
   STRONGER CORES...BUT A TORNADO OR TWO WILL BE POSSIBLE AS LOW-LEVEL
   SHEAR INCREASES LATE IN THE DAY.

   ..JEWELL.. 04/27/2014

[jaxjagman]

[jaxjagman]

[Stovepipe]

Nader warning as of 1:30 pm eastern:

 

[1234snow]

HRRR depicts a squall line moving throughout East Tn this evening. Going to be a dangerous afternoon and evening.

[Stovepipe]

HRRR depicts a squall line moving throughout East Tn this evening. Going to be a dangerous afternoon and evening.

 

Here's hour 15 valid 6z:

 

 

That'll be loud enough to wake up the kiddos.  Hope we can avoid hail.  If my plants get chopped up I'll cry.

[1234snow]

These storms are still severe warned and moving generally to the East. If it holds together then the Tri Cities will be affected and maybe Knoxville. This is not really even the main show that is coming later on.

[1234snow]

Hot off the presses:

SEL0

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 110

NWS STORM PREDICTION CENTER NORMAN OK

235 PM EDT MON APR 28 2014

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF

SOUTHEAST KENTUCKY

EASTERN TENNESSEE

FAR WESTERN VIRGINIA

* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 235 PM UNTIL

800 PM EDT.

* PRIMARY THREATS INCLUDE...

A COUPLE TORNADOES POSSIBLE

SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE

ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE

MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH OF BRISTOL

TENNESSEE TO 10 MILES EAST SOUTHEAST OF CHATTANOOGA TENNESSEE.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 108...WW 109...

DISCUSSION...BROKEN BAND OF STORMS WILL CONTINUE TO SPREAD EWD

ACROSS ERN TN/SE KY THIS AFTERNOON...ALONG AN OUTFLOW BOUNDARY FROM

MORNING CONVECTION AND IN ADVANCE OF A WEAK MCV. VERTICAL SHEAR AND

INSTABILITY WILL BE SUFFICIENT FOR SOME RISK OF SUPERCELLS...WITH AN

ATTENDANT RISK FOR A COUPLE TORNADOES...LARGE HAIL...AND DAMAGING

GUSTS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 25035.

...THOMPSON

[1234snow]

TOR warning back out again this time for SWVA counties as well.

[Mr Bob]

North Tupelo looks to have gotten hit....hopefully our Mississippi folks are doing okay...long 24 hours ahead.