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April 1-4 Severe Threat


snowlover2

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SPC hinting at the day 3 possibly needing a moderate risk in later outlooks.

 

 

 

...ERN SRN PLAINS THROUGH LOWER-MID MS...WRN TN AND OH VALLEYS...

POTENTIAL EXISTS FOR A MORE WIDESPREAD SEVERE EVENT ON THURSDAY WITH
DAMAGING WIND...LARGE HAIL AND TORNADOES POSSIBLE ESPECIALLY FROM
THE LOWER-MID MS VALLEYS INTO THE WRN TN VALLEY. PORTIONS OF THIS
AREA MAY NEED TO BE INCLUDED IN A MODERATE RISK IN LATER OUTLOOKS.

THE VIGOROUS SHORTWAVE TROUGH MAY TAKE ON A POSITIVE TO SLIGHTLY
NEGATIVE TILT AS IT EJECTS ENEWD THROUGH THE CNTRL/SRN PLAINS INTO
THE MID-LOWER MS VALLEY THURSDAY. A MOIST WARM SECTOR WITH STEEP
LAPSE RATES AND MODERATE TO STRONG INSTABILITY WILL PRECEDE THIS
FEATURE. FORCING ALONG THE ATTENDANT COLD FRONT AND DRYLINE MAY
CONTRIBUTE TO THUNDERSTORM INITIATION FROM ERN OK THROUGH CNTRL/ERN
TX. HEIGHT FALLS WILL ALSO DEVELOP ACROSS A PORTION OF THE WARM
SECTOR WHICH COMBINED WITH DIABATIC WARMING SUGGEST THE CAP SHOULD
WEAKEN ALLOWING FOR STORM DEVELOPMENT ACROSS THE WARM SECTOR FROM AR
INTO SRN AND CNTRL MO. THE LLJ WILL STRENGTHEN WITHIN ZONE OF HEIGHT
FALLS ACROSS THE LOWER-MID MS VALLEY REGION AND SHIFT EWD INTO THE
TN AND OH VALLEYS OVERNIGHT. MID-UPPER JET STREAK ATTENDING THE
PROGRESSIVE SHORTWAVE TROUGH WILL RESULT IN 40-50 KT 0-6 KM SHEAR.
ANY STORMS INITIATING IN WARM SECTOR WILL LIKELY DEVELOP SUPERCELL
STRUCTURES WITH VERY LARGE HAIL AND DAMAGING WIND LIKELY. POTENTIAL
WILL ALSO EXIST FOR TORNADOES...ESPECIALLY OVER THE LOWER-MID MS
VALLEY INTO THE WRN TN VALLEY AS THE LLJ STRENGTHENS DURING THE LATE
AFTERNOON AND EVENING.

OTHER STORMS WILL LIKELY DEVELOP ALONG THE COLD FRONT. STORMS WILL
LIKELY BEGIN TO GROW UPSCALE INTO ONE OR MORE MCSS OVERNIGHT WITH A
CONTINUED SEVERE THREAT ACROSS A PORTION OF THE LOWER MS...TN AND OH
VALLEYS OVERNIGHT.

 

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Looks like kind of a tricky call here.  There's a chance we may not get solidly into the warm sector until later Thursday (but not like it will be cold during the day) but given the deepening system and models advertising respectable elevated instability (and possibly some surface based instability) well into the overnight hours, I think there will be some severe threat here well after dark.  Best ingredients may be found farther south/west though as the SPC outlook indicates.

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It's a shame the timing sucks for IN.  If this whole thing slowed down by ~12 hours it'd be a good local chase day, but time's pretty much up on that happening.

 

Originally I thought maybe there would be a play in Ohio Friday, but it seems like the trend is to keep reducing instability each model cycle to the point where it's essentially nil on the GFS now.

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Day 2 moderate risk.

 

 

 

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED APR 02 2014

VALID 031200Z - 041200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER A PORTION OF THE LOW-MID MS
VALLEY AND WRN TN VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM ERN PORTIONS OF
THE SRN PLAINS THROUGH THE LOWER-MID MS VALLEY...TN VALLEY AND OH
VALLEY...

POTENTIAL EXISTS FOR NUMEROUS SEVERE STORMS THURSDAY WITH DAMAGING
WIND...LARGE HAIL AND TORNADOES POSSIBLE...ESPECIALLY FROM THE
LOWER-MID MS VALLEYS INTO THE WRN TN AND OH VALLEYS.

...SYNOPSIS...

MODELS SOLUTIONS HAVE CONVERGED ON TIMING...AMPLITUDE AND GENERAL
CHARACTER OF A VIGOROUS SHORTWAVE TROUGH THAT WILL EJECT NEWD
THROUGH THE CNTRL/SRN PLAINS INTO THE LOWER-MID MS VALLEY ON
THURSDAY. SFC LOW WILL DEEPEN AS IT DEVELOPS NEWD THROUGH THE MID MS
VALLEY DURING THE AFTERNOON AND EVENING BENEATH CORRIDOR OF
INCREASING UPPER DIVERGENCE. BY THURSDAY MORNING A COLD FRONT WILL
LIKELY EXTEND FROM THE SFC LOW SITUATED OVER SERN KS SWWD THROUGH
NWRN OK AND NWRN TX. THIS FRONT WILL MOVE SEWD OVERTAKING THE
DRYLINE SITUATED ACROSS OK AND TX. BY THE END OF THE PERIOD THE
FRONT SHOULD STRETCH FROM A SURFACE LOW OVER THE UPPER GREAT LAKES
AREA SWWD THROUGH WRN TN...LA AND THE TX COASTAL AREA. WARM FRONT
EXTENDING EWD FROM THE LOW THROUGH CNTRL/NRN MO INTO THE OH VALLEY
EARLY THURSDAY WILL LIFT SLOWLY NWD DURING THE DAY.

...ERN SRN PLAINS THROUGH LOWER-MID MS VALLEY AND WRN TN VALLEY...

VIGOROUS SHORTWAVE TROUGH SHOULD TAKE ON A SLIGHTLY NEGATIVE TILT AS
IT EJECTS ENEWD INTO THE MID MS VALLEY LATER THURSDAY. RICHER GULF
MOISTURE WITH MID 60S DEWPOINTS HAVE ALREADY ADVECTED INTO MUCH OF
ERN TX AND LA AND WILL BE IN PLACE ACROSS THE MID-LOWER MS VALLEY AT
THE START OF THIS PERIOD. THE MOIST BOUNDARY LAYER BENEATH STEEP
LAPSE RATES WILL RESULT IN MODERATE TO STRONG INSTABILITY IN
PRE-FRONTAL WARM SECTOR WITH 1500-2500 J/KG MLCAPE LIKELY. A FEW
ELEVATED STORMS MAY BE ONGOING ACROSS A PORTION OF THE LOWER MS
VALLEY EARLY THURSDAY. HOWEVER...IT DOES NOT APPEAR MOST OF WARM
SECTOR WILL SUFFER FROM EARLY CONVECTIVE OVERTURNING EXCEPT FARTHER
NORTH WITHIN ZONE OF STRONGER ISENTROPIC ASCENT FROM NRN MO INTO THE
OH VALLEY. A FEW BREAKS IN THE MULTI-LAYER CLOUD DECK SHOULD RESULT
IN AT LEAST MODEST WARMING AND DESTABILIZATION OF THE BOUNDARY
LAYER.

SURFACE-BASED THUNDERSTORM INITIATION WILL BECOME PROBABLE ACROSS
THE LOWER-MIDDLE MS VALLEY WARM SECTOR THURSDAY AFTERNOON AS THE CAP
WEAKENS WHERE STRENGTHENING LLJ WITHIN ZONE OF HEIGHT FALLS WILL
COINCIDE WITH THE DESTABILIZING BOUNDARY LAYER. THESE STORMS MAY
INITIALLY BE DISCRETE IN CHARACTER...AND VERTICAL SHEAR AND
LOW-LEVEL HODORAPHS WILL BECOME INCREASINGLY FAVORABLE FOR
SUPERCELLS CAPABLE OF LARGE HAIL AND TORNADOES. ACTIVITY WILL
EVENTUALLY SPREAD EWD INTO WRN PORTIONS OF THE TN VALLEY DURING THE
EVENING AND OVERNIGHT WITH A CONTINUED SEVERE THREAT. OTHER STORMS
WILL LIKELY INITIATE FARTHER FROM ERN KS/WRN MO...ERN OK AND
POSSIBLY INTO ERN TX AS THE COLD FRONT OVERTAKES THE DRYLINE...AND
SOME STORMS WILL EVENTUALLY GROW UPSCALE INTO ONE OR MORE MCSS
OVERNIGHT WITH AN INCREASING THREAT FOR DAMAGING WIND.

...OH VALLEY REGION...

MOSTLY ELEVATED THUNDERSTORMS SHOULD BE ONGOING EARLY
THURSDAY...PRIMARILY WITHIN ZONE OF ISENTROPIC ASCENT ALONG AND
NORTH OF WARM FRONT ACROSS THE OH VALLEY. THIS ACTIVITY SHOULD SHIFT
EAST DURING THE DAY. IN ITS WAKE...THETA-E ADVECTION ALONG THE
STRENGTHENING LOW-LEVEL JET AND NEWD ADVECTION OF STEEPER LAPSE
RATES SHOULD CONTRIBUTE TO DESTABILIZATION. PRIMARY SEVERE THREAT IN
THIS REGION SHOULD DEVELOP THURSDAY AFTERNOON AND AGAIN OVERNIGHT AS
DEEP LAYER WINDS STRENGTHEN AHEAD OF MCS THAT IS EXPECTED TO EVOLVE
UPSTREAM ACROSS THE MID MS VALLEY REGION. DAMAGING WIND AND A FEW
TORNADOES WILL BE THE PRIMARY THREATS.

..DIAL.. 04/02/2014

 

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Day 2 moderate risk.

 

 

I overlaid the county outlines on SPC's website and the northern border of the 30% hatched cuts right through LAF/Tippecanoe county.  Kinda goes with what I was saying about it being a tricky call as far as whether we get into a better threat here.  Latest models look relatively similar to last night...surface based instability develops here especially during the evening/overnight hours but drops off as you go north.  Can't rule out a nocturnal tornado threat but I suspect the main threat locally will be damaging wind.

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I overlaid the county outlines on SPC's website and the northern border of the 30% hatched cuts right through LAF/Tippecanoe county.  Kinda goes with what I was saying about it being a tricky call as far as whether we get into a better threat here.  Latest models look relatively similar to last night...surface based instability develops here especially during the evening/overnight hours but drops off as you go north.  Can't rule out a nocturnal tornado threat but I suspect the main threat locally will be damaging wind.

Yeah I agree, I do think there is a decent likelihood of a QLCS racing across IL/IN tomorrow evening and into the night.

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Just some context about the April 3 date.  Everyone remembers it for the Super Outbreak but over half of the years since 1950 have had at least 1 tornado on that day.  1956, 1957, 1968, 1989 and 2012 had 20+ tornadoes.  1956 stands out the most for this subforum.

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Tonight's NAM is looking half way decent especially over Northern MO near the low/wf. I imagine SPC may extend the moderate risk a little further NW to reflect what the NAM is showing tonight. The warm front may not get as far north as what the NAM is showing depending on how much precip is falling north of it so it may be something to watch. Am planning on chasing this system as its only about a 4.5 hour drive away and the fact this is the only event that I can chase for almost 2.5 weeks. I hate chasing in MO but at least the trees have no leaves on them attm :) This mornings GFS was showing another possible area over Western IL along I-72 an hour or so

before sunset so will keep an eye on that as well.

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Looks like the STL area got hit this morning. 

 

And this right now in southern IL...

 

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
623 AM CDT THU APR 3 2014

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* TORNADO WARNING FOR...
EASTERN CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...

* UNTIL 700 AM CDT

* AT 620 AM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
TORNADO WAS LOCATED NEAR BREESE...AND MOVING EAST AT 55 MPH.

HAZARD...TORNADO.

SOURCE...RADAR INDICATED ROTATION.

IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT
SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED. DAMAGE
TO ROOFS...WINDOWS AND VEHICLES WILL OCCUR. TREE DAMAGE IS
LIKELY.

* THIS DANGEROUS STORM WILL BE NEAR...
BOULDER AROUND 635 AM CDT.
SHATTUC AROUND 640 AM CDT.

OTHER LOCATIONS IN THE WARNING INCLUDE HUEY...HOFFMAN AND FERRIN.

THIS WARNING INCLUDES CARLYLE LAKE RECREATIONAL AREA.

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Headed towards the St Louis Metro in about an hour if it continues on its current path.

 

TORNADO WARNING
MOC071-073-151-032330-
/O.NEW.KLSX.TO.W.0012.140403T2306Z-140403T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
606 PM CDT THU APR 3 2014

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* TORNADO WARNING FOR...
NORTHWESTERN FRANKLIN COUNTY IN EAST CENTRAL MISSOURI...
GASCONADE COUNTY IN EAST CENTRAL MISSOURI...
SOUTHEASTERN OSAGE COUNTY IN CENTRAL MISSOURI...

* UNTIL 630 PM CDT

* AT 602 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
TORNADO WAS LOCATED NEAR RICH FOUNTAIN...AND MOVING EAST AT 50 MPH.

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Little activity in this thread, but I will post anyway...

 

Confirmed tornado near the STL Metro moving into IL.

 

TORNADO WARNING
ILC119-163-MOC189-510-040145-
/O.NEW.KLSX.TO.W.0014.140404T0123Z-140404T0145Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
823 PM CDT THU APR 3 2014

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHWESTERN MADISON COUNTY IN SOUTHWEST ILLINOIS...
NORTHERN ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...
CENTRAL ST. LOUIS COUNTY IN EAST CENTRAL MISSOURI...
ST. LOUIS CITY IN EAST CENTRAL MISSOURI...

* UNTIL 845 PM CDT

* AT 816 PM CDT...A CONFIRMED TORNADO WAS LOCATED NEAR GLENDALE...AND
MOVING EAST AT 45 MPH.

HAZARD...DAMAGING TORNADO AND QUARTER SIZE HAIL. SPOTTERS
REPORTED A TORNADO NEAR TWIN OAKS AT 810 PM CDT.

SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO

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Seems reasonable based on the current front position. 

 

 

Front seems very sluggish.  My earlier call is looking bad at this point.  Temps will probably rise but doesn't look like anything close to what could've been.  This also has ramifications with instability as we will be realizing little to nothing at the surface.

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