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June 1-7 Severe Threat


snowlover2

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Moderate risk issued on new day 2.

 

 

 

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT MON JUN 02 2014

VALID 031200Z - 041200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM NEB INTO NRN KS...SRN
IA...NRN MO AND WRN IL...

...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE CNTRL AND
NRN PLAINS THROUGH THE MID-UPPER MS VALLEY AREAS...

...SUMMARY...
NUMEROUS SEVERE STORMS ARE FORECAST TUESDAY FROM A PORTION OF THE
CENTRAL PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY REGIONS. LARGE
HAIL AND WIDESPREAD DAMAGING WIND ARE LIKELY...BUT TORNADOES WILL
ALSO BE POSSIBLE...INCLUDING POSSIBILITY OF A FEW STRONG TORNADOES.

...SYNOPSIS...

SHORTWAVE TROUGH CURRENTLY JUST OFF THE CA COAST WILL REACH THE
GREAT BASIN OR CENTRAL ROCKIES BY 12Z TUESDAY. THIS FEATURE WILL
THEN RAPIDLY EJECT EWD THROUGH THE CNTRL PLAINS DURING THE DAY AND
INTO THE MIDDLE TO UPPER MS VALLEY OVERNIGHT...DEAMPLIFYING IN THE
PROCESS. A STRONG UPPER JET WITH 60-70 KT AT 500 MB WILL ACCOMPANY
THIS IMPULSE. AT THE SFC A FRONT WILL STALL FROM THE OH VALLEY WWD
INTO NEB WHILE A LEE CYCLONE DEEPENS OVER THE CNTRL PLAINS IN
ASSOCIATION WITH INCREASING WLYS ALOFT AND FORCING ATTENDING THE
EJECTING SHORTWAVE TROUGH. THIS FEATURE WILL THEN SHIFT EWD ALONG
THE BOUNDARY THROUGH THE CNTRL PLAINS TUESDAY NIGHT. TO THE SOUTH OF
THE SFC LOW A DRYLINE WILL SETUP ACROSS THE CNTRL HIGH PLAINS
TUESDAY AFTERNOON.

...CNTRL PLAINS THROUGH THE MID-UPPER MS VALLEY REGIONS...

POTENTIAL EXISTS FOR SIGNIFICANT SEVERE EVENTS TUESDAY WITH A THREAT
FOR VERY LARGE HAIL...TORNADOES AND WIDESPREAD DAMAGING WIND.


A FEW STORMS MAY BE ONGOING EARLY TUESDAY WITHIN ZONE OF ISENTROPIC
LIFT AND THETA-E ADVECTION NORTH OF THE WARM FRONT AND ON NOSE OF A
SLY LLJ ACROSS PORTIONS OF WRN NEB INTO SD. RICH GULF MOISTURE WITH
UPPER 60S TO NEAR 70 DEWPOINTS WILL RESIDE IN WARM SECTOR SOUTH OF
THE FRONT THAT WILL LIFT NWD INTO NEB AND SRN IA. SOME UNCERTAINTY
EXISTS AS TO HOW FAR NORTH THIS BOUNDARY WILL ADVANCE...ESPECIALLY
ACROSS THE MS VALLEY WHERE INFLUENCE OF DOWNSTREAM SHORTWAVE TROUGH
MAY LIMIT OR DELAY ITS NWD PROGRESS. MEANWHILE...PLUME OF STEEP
MID-LEVEL LAPSE RATES ASSOCIATED WITH THE EML WILL ADVECT THROUGH
THE CNTRL PLAINS MOIST WARM SECTOR WITHIN BELT OF STRENGTHENING
WLYS. THESE PROCESSES WILL CONTRIBUTE TO STRONG INSTABILITY SOUTH OF
THE FRONT /2000-3000 J/KG MLCAPE/ AS THE SFC LAYER WARMS. HEIGHT
FALLS...STRENGTHENING SLY LLJ...AND BOUNDARY LAYER DESTABILIZATION
SHOULD RESULT IN INCREASING POTENTIAL FOR ADDITIONAL STORMS TO
DEVELOP ALONG THAT PORTION OF THE FRONTAL ZONE CLOSER TO THE WARM
SECTOR TUESDAY AFTERNOON.

VERTICAL SHEAR INCREASING TO AOA 50 KT AND STRONG INSTABILITY WILL
SUPPORT ORGANIZED STORMS INCLUDING SUPERCELLS WITH ANY ACTIVITY
DEVELOPING ALONG THE FRONT AND NEAR TRIPLE POINT AND POSSIBLY
FARTHER SOUTH ALONG DRYLINE INTO WRN KS. VERY LARGE HAIL AND
DAMAGING WIND WILL BE LIKELY WITH INITIAL STORMS. ALSO STORM MOTION
VECTORS WOULD SUPPORT STORMS THAT DEVELOP ON WARM FRONT TO MOVE ELY
OR ESELY...LIKELY REMAINING IN PROXIMITY TO THIS BOUNDARY WHERE
INFLUX OF HIGH THETA-E AIR AND 0-2 KM HODOGRAPHS WILL BE
MAXIMIZED...SUPPORTING A THREAT FOR TORNADOES...A FEW OF WHICH COULD
BE STRONG. DURATION OF THE MORE SIGNIFICANT TORNADO THREAT WILL
DEPEND ON HOW QUICKLY STORMS BEGIN TO CONGEAL AND GROW UPSCALE.

STORMS OVER NEB SHOULD EVENTUALLY EVOLVE INTO AN MCS AND FORWARD
PROPAGATE EWD...SUSTAINED BY THE STRENGTHENING SLY LLJ. GIVEN THE
EXPECTED MAGNITUDE OF INSTABILITY AND NATURE OF THE VERTICAL WIND
PROFILES...THREAT WILL EXIST FOR WIDESPREAD DAMAGING WIND WITH BOW
ECHO AND LEWP STRUCTURES AND EMBEDDED SUPERCELLS...ESPECIALLY FROM
PORTIONS OF NEB INTO THE MS VALLEY REGION.

...CNTRL AND NRN HIGH PLAINS...

OTHER STORMS MAY DEVELOP OVER THE HIGHER TERRAIN OF WY AND MT AND
SPREAD INTO THE HIGH PLAINS WHERE VERTICAL SHEAR AND INSTABILITY
WILL SUPPORT A FEW SEVERE STORMS INCLUDING SUPERCELLS. LARGE HAIL
AND DAMAGING WIND SHOULD BE THE MAIN THREATS.

..DIAL.. 06/02/2014

 

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post-4544-0-54027300-1401688722_thumb.gi

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It's looking very likely that there will be back to back moderate risks.  The question I have is whether they will already pull the trigger on the day 3 outlook or wait until it gets into the day 2 range.  My money would be on the latter but I'm usually not very good trying to predict SPC's thoughts. 

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It's looking very likely that there will be back to back moderate risks.  The question I have is whether they will already pull the trigger on the day 3 outlook or wait until it gets into the day 2 range.  My money would be on the latter but I'm usually not very good trying to predict SPC's thoughts. 

 

 

STORMS OVER NEB SHOULD EVENTUALLY EVOLVE INTO AN MCS AND FORWARD

PROPAGATE EWD...SUSTAINED BY THE STRENGTHENING SLY LLJ. GIVEN THE

EXPECTED MAGNITUDE OF INSTABILITY AND NATURE OF THE VERTICAL WIND

PROFILES...THREAT WILL EXIST FOR WIDESPREAD DAMAGING WIND WITH BOW

ECHO AND LEWP STRUCTURES AND EMBEDDED SUPERCELLS...ESPECIALLY FROM

PORTIONS OF NEB INTO THE MS VALLEY REGION.

That part of the day 2 has me leaning to them going day 3 moderate. That to me basically says derecho without them actually saying it.

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Considering the new day 3 came out about 10 minutes later than normal, thought they were going moderate but they didn't. The text isn't even that long or detailed.

 

 

 

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0239 AM CDT MON JUN 02 2014

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE OH
VALLEY...

...SUMMARY...
STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP PRIMARILY THROUGH
THE OHIO VALLEY REGION WEDNESDAY WITH A THREAT FOR MAINLY DAMAGING
WIND AND LARGE HAIL. OTHER MORE ISOLATED STRONG TO SEVERE STORMS
WILL BE POSSIBLE FROM SOUTHERN KANSAS INTO NORTHERN OKLAHOMA AND THE
NORTHERN THROUGH CENTRAL HIGH PLAINS AREAS.

...SYNOPSIS...

PROGRESSIVE UPPER PATTERN WILL PERSIST OVER THE NRN HALF OF THE
COUNTRY WEDNESDAY. A FAST MOVING LOW AMPLITUDE SHORTWAVE TROUGH WILL
CONTINUE THROUGH THE OH VALLEY...DEAMPLIFYING AS IT BECOMES ABSORBED
IN A BROADER SCALE UPPER TROUGH CENTERED OVER SERN CANADA. A FRONTAL
BOUNDARY WILL PERSIST FROM THE OH VALLEY SWWD INTO KS AND OK. MODELS
DIFFER ON LOCATION/MOVEMENT OF THIS BOUNDARY WITH THE SPECTRAL
MODELS REMAINING FARTHER SOUTH WITH THE POSITION ACROSS THE OH
VALLEY COMPARED TO THE NAM.

...OH VALLEY THROUGH CNTRL APPALACHIAN REGION...

RICH GULF MOISTURE WILL RESIDE IN THE OH VALLEY WARM SECTOR SOUTH OF
THE FRONT SUPPORTING MODERATE INSTABILITY AS THE SFC LAYER WARMS. AN
MCS WILL LIKELY BE IN PROGRESS NORTH OF THIS BOUNDARY OVER THE
MID-UPPER MS VALLEY REGION. ACTIVITY WILL DEVELOP EWD THROUGH THE OH
VALLEY DURING THE DAY WITHIN ZONE OF ASCENT ASSOCIATED WITH THE
PROGRESSIVE SHORTWAVE TROUGH AND ON NOSE OF ATTENDANT LLJ. STORMS
WILL INTENSIFY AND REDEVELOP AS THE WARM SECTOR DESTABILIZES...AND
WIND PROFILES WILL SUPPORT POTENTIAL FOR SUPERCELLS AND BOWING
SEGMENTS AS SOME STORMS GROW UPSCALE INTO MCS CLUSTERS. DAMAGING
WIND...LARGE HAIL AND A FEW TORNADOES WILL BE POSSIBLE.

.

..DIAL.. 06/02/2014

 

post-4544-0-82362400-1401695022_thumb.gi

post-4544-0-73793100-1401695029_thumb.gi

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Slight risk it is. They took it waaaaaay south with this run too. hmmmm............

 

 

They're basically going with the non-NAM consensus which is probably not dumb at this point.  Although an early peek at the 12z NAM suggests it's going to remain on the northern side yet again.

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They're basically going with the non-NAM consensus which is probably not dumb at this point.  Although an early peek at the 12z NAM suggests it's going to remain on the northern side yet again.

Roger that, thanks for some clarification. Haven't been in a position to be able to pull up some models yet this morning.

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We'll see what the other 12z runs do but there's literally a 200 mile or more north/south gap between the old 00z GFS/ECMWF and the 12z NAM wrt the position of the surface low at 00z Thursday.  Although I'm skeptical of the NAM it should be getting to the point where it wouldn't whiff that badly so perhaps we will ultimately end up with some sort of weighted compromise.  

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We'll see what the other 12z runs do but there's literally a 200 mile or more north/south gap between the old 00z GFS/ECMWF and the 12z NAM wrt the position of the surface low at 00z Thursday.  Although I'm skeptical of the NAM it should be getting to the point where it wouldn't whiff that badly so perhaps we will ultimately end up with some sort of weighted compromise.  

 

The NAM is really far north with the surface low?  What is this January? ;)

 

Definitely interested to see remaining 12z guidance and then next couple NAM runs.  I'll be in Cincinnati on Wednesday so pulling for the GFS :P  The NAM does look very impressive though.

 

CIPS analog guidance (based on GFS) is waving the red flag as well....

post-165-0-63309200-1401723608_thumb.png

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Really impressive winds out here with this line even with no lightning.

 

 

 

nice shape but returns continue to struggle...shame we couldn't get a couple more hours to destabilize before it hit

 

anyways, looks like it's heading right for me as well

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I'm a bit uncomfortable using it but man, 12z NAM forecast soundings look impressive around here on Wednesday.

 

The differences between it and the GFS are pretty crazy for being 2 and a half days out. The 12z NAM shows what would have the potential to be a full blown tornado outbreak across IN on Wednesday. GFS shunts all of it down towards the OH River, and while still having impressive soundings, doesn't show the degree of veering with height that the NAM does with the wind fields.

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The differences between it and the GFS are pretty crazy for being 2 and a half days out. The 12z NAM shows what would have the potential to be a full blown tornado outbreak across IN on Wednesday. GFS shunts all of it down towards the OH River, and while still having impressive soundings, doesn't show the degree of veering with height that the NAM does with the wind fields.

 

Yeah, I believe thats the dilemma right now. I was surprised with the differences, as well. Might take another day for the models to come to a consensus with this one.

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