July 6-8 Severe Weather

[snowlover2]

New day 1

 

 

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1242 AM CDT SUN JUL 06 2014  
 
VALID 061200Z - 071200Z  
 
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID AND  
UPPER MS VALLEY AND WRN GREAT LAKES...  
   
..SUMMARY  
 
SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WIND GUSTS...LARGE HAIL AND  
A TORNADO OR TWO WILL BE POSSIBLE ACROSS PARTS OF THE MID AND UPPER  
MISSISSIPPI RIVER VALLEY AND MIDWEST THIS AFTERNOON INTO TONIGHT.  
   
..SYNOPSIS  
 
FALLING HEIGHTS ASSOCIATED WITH SEWD PROGRESSING SHORTWAVE TROUGH  
WILL OVERSPREAD THE MID/UPPER MS VALLEY AND GREAT LAKES TODAY. AT  
THE SAME TIME...A SFC COLD FRONT WILL PROGRESS EWD ACROSS THE UPPER  
MIDWEST...EXTENDING SWWD FROM A SFC LOW OVER ONTARIO THROUGH NW WI  
INTO FAR SE MN/CENTRAL IA BY 00Z/MON. SLY LOW LEVEL FLOW WILL  
MAINTAIN A VERY MOIST AIRMASS ACROSS THE REGION...AND MODERATE TO  
STRONG INSTABILITY WILL DEVELOP BY AFTERNOON AS TEMPERATURES WARM  
INTO THE 80S. SCATTERED THUNDERSTORMS WITH AN ATTENDANT THREAT OF  
LARGE HAIL AND DAMAGING WINDS...AND POSSIBLE A FEW TORNADOES...ARE  
EXPECTED TO DEVELOP DURING THE AFTERNOON AND SPREAD SEWD TOWARD ERN  
IA/NRN IL INTO THE EVENING AND OVERNIGHT HOURS.  
   
..MID/UPPER MS VALLEY AND WRN GREAT LAKES REGION  
 
A VERY MOIST AIRMASS /DEW POINTS FROM THE MID 60S TO LOW 70S/ WILL  
BE MAINTAINED IN S/SWLY WAA REGIME AHEAD OF THE SFC COLD FRONT. AS  
AFTERNOON TEMPERATURES WARM INTO THE 80S...MODERATE TO STRONG  
INSTABILITY WILL DEVELOP IN CONJUNCTION WITH STEEPENING MIDLEVEL  
LAPSE RATES. EARLY DAY CLOUD COVER ASSOCIATED WITH CURRENT  
CONVECTION ONGOING ACROSS ERN ND AND NRN MN IS LIKELY ACROSS  
PORTIONS OF THE SLIGHT RISK AREA. THIS COULD TURN OUT TO BE AN  
OVERALL POSITIVE...DELAYING CONVECTIVE DEVELOPMENT UNTIL LATER IN  
THE AFTERNOON WHEN STRONGER HEIGHT FALLS AND MIDLEVEL FLOW WILL  
OVERSPREAD THE REGION...BUT COULD IMPACT THE WRN AND NRN EXTENT OF  
SEVERE POTENTIAL DUE TO LIMITED SFC HEATING. REGARDLESS...STORMS ARE  
EXPECTED TO DEVELOP NEAR THE COLD FRONT BY 21-00Z FROM WRN/CNTRL WI  
INTO NE IA. 30-40 KT EFFECTIVE SHEAR WITH SLIGHTLY VEERING WIND  
PROFILES WILL FAVOR ROTATING UPDRAFTS/SUPERCELLS INITIALLY...BUT A  
TRANSITION TOWARD MORE LINEAR MODES IS EXPECTED INTO THE EVENING.  
LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS...BUT 0-1 KM  
SRH VALUES AROUND 100-200 M2/S2...MEAN MIXING RATIOS GREATER THAN 14  
G/KG AND LOW LCL HEIGHTS WILL BE SUFFICIENT FOR A FEW TORNADOES.  
   
..SRN LOWER MI  
 
ADDITIONAL THUNDERSTORMS MAY DEVELOP IN VICINITY OF LAKE BREEZE  
CIRCULATIONS DURING THE AFTERNOON IN A WEAK TO MODERATELY UNSTABLE  
ENVIRONMENT. STRONGER DEEP LAYER FLOW WILL REMAIN TO THE WEST UNTIL  
OVERNIGHT...BUT 20-30 KT 0-6 KM SHEAR WILL BE ADEQUATE FOR SOME  
SEMI-ORGANIZED STORM STRUCTURES/CLUSTERS. MARGINALLY SEVERE WIND AND  
HAIL MAY ACCOMPANY ANY AFTERNOON CONVECTION. OVERNIGHT...LINEAR  
CONVECTION ASSOCIATED WITH THE MAIN SHORTWAVE TROUGH AND SFC COLD  
FRONT COULD ALSO MOVE INTO THE REGION...BUT WHETHER OR NOT IT WILL  
REMAIN SEVERE AFTER CROSSING THE LAKE WELL AFTER PEAK HEATING  
REMAINS UNCERTAIN.  
 
..LEITMAN/ROGERS.. 07/06/2014 

 

[snowlover2]

New day 2

 

 

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0100 AM CDT SUN JUL 06 2014  
 
VALID 071200Z - 081200Z  
 
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL PLAINS/UPPER  
MIDWEST TO THE OH VALLEY...  
   
..SUMMARY  
 
ISOLATED STRONG TO SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WINDS  
AND SEVERE HAIL ARE EXPECTED MONDAY AFTERNOON AND NIGHT FROM  
PORTIONS OF THE CENTRAL PLAINS AND UPPER MIDWEST TO THE OHIO VALLEY.  
   
..SYNOPSIS  
 
LONGWAVE PATTERN AMPLIFICATION WILL CONTINUE TO OCCUR THROUGH  
MONDAY. THIS WILL BE HIGHLIGHTED BY INCREASINGLY PREVALENT CYCLONIC  
WESTERLIES OVER THE NORTH-CENTRAL/NORTHEAST CONUS...WHILE AN UPPER  
RIDGE CONTINUES TO SLOWLY SHIFT WESTWARD OVER THE GREAT BASIN.  
   
..CENTRAL PLAINS/MIDDLE MO VALLEY/UPPER MIDWEST  
 
A WEAK COLD FRONT IS EXPECTED TO SPREAD SOUTHEASTWARD AND GRADUALLY  
OVERTAKE A QUASI-STATIONARY FRONTAL BOUNDARY AND ASSOCIATED CORRIDOR  
OF RELATIVELY RICH MOISTURE MONDAY AFTERNOON/NIGHT. PROBABLE  
SURFACE-BASED TSTM DEVELOPMENT WILL BE AIDED BY AN  
AMPLIFYING/SOUTHEAST-SPREADING SHORTWAVE TROUGH AND ASSOCIATED 50+  
KT MID-LEVEL SPEED MAXIMA...WITH DEEP CONVECTIVE DEVELOPMENT  
ANTICIPATED ACROSS PARTS OF SOUTHEAST SD AND EAST/CENTRAL NEB INTO  
IA/NORTHERN MO BY LATE AFTERNOON AND EVENING. SOME SUPERCELLS  
CAPABLE OF LARGE HAIL/PERHAPS A TORNADO WILL INITIALLY BE POSSIBLE.  
HOWEVER...THESE STORMS SHOULD TEND TO CONSOLIDATE/GROW UPSCALE INTO  
A SOUTHEASTWARD-MOVING MCS CAPABLE OF DAMAGING WINDS MONDAY NIGHT  
ACROSS THE MO VALLEY/MIDDLE MS RIVER VALLEY.  
 
WHILE THE DETAILS ARE A LITTLE LESS CERTAIN...OTHER SEVERE TSTMS  
WILL ALSO BE POSSIBLE FARTHER NORTH MONDAY AFTERNOON/EVENING ACROSS  
PARTS OF THE UPPER MIDWEST. THIS INCLUDES NORTHERN IA AND PORTIONS  
OF MN/WI IN VICINITY OF A WEAK SURFACE LOW AND A MORE MODESTLY  
MOIST/UNSTABLE BOUNDARY LAYER.  
   
..OH VALLEY  
 
NEAR/SOUTH OF A SLOW SOUTHEASTWARD-MOVING COLD FRONT...SEVERE TSTMS  
WILL BE POSSIBLE PARTICULARLY MONDAY AFTERNOON/EARLY EVENING. EARLY  
DAY PRECIPITATION/CLOUD COVER COULD BE A FACTOR...BUT MODERATE  
DESTABILIZATION CAN GENERALLY BE EXPECTED BY MONDAY AFTERNOON ACROSS  
MUCH OF THE REGION AHEAD OF THE FRONT AND/OR SOUTH OF ANY RESIDUAL  
THICKER CLOUD COVER. AS MUCH AS 30-40 KT OF EFFECTIVE SHEAR WILL  
SUPPORT WELL-ORGANIZED MULTICELLS/LINE SEGMENTS CAPABLE OF DAMAGING  
WINDS AND SEVERE HAIL. 

 

[snowlover2]

New day 3

 

 

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT SUN JUL 06 2014

VALID 081200Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE OZARKS/OH RIVER
VALLEY AND TN RIVER VALLEY...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WINDS AND HAIL WILL BE
POSSIBLE TUESDAY ESPECIALLY ACROSS PORTIONS OF THE OZARKS...OHIO
VALLEY...AND TENNESSEE VALLEY.

...OZARKS TO OH/TN RIVER VALLEYS AND NORTHEAST STATES...
CURRENT THINKING IS THAT AN MCS WILL BE ONGOING ACROSS THE MIDDLE MS
RIVER VALLEY/MIDWEST TUESDAY MORNING. PARTICULARLY ON THE
SOUTHERN/EASTERN FRINGES OF THIS EARLY DAY MCS...SURFACE-BASED STORM
DEVELOPMENT/MATURATION IS EXPECTED TUESDAY AFTERNOON ACROSS MUCH OF
THE OH VALLEY AND POSSIBLY THE OZARKS NEAR/AHEAD OF A
SOUTHEASTWARD-MOVING COLD FRONT. MODERATE BUOYANCY WITH UPWARDS OF
2000-2500 J/KG OF MLCAPE IS EXPECTED WITHIN THE WARM SECTOR.
ALTHOUGH THE STRONGEST DEEP-LAYER WIND FIELD WILL RESIDE TO THE
NORTH OF THE FRONTAL ZONE...30-40 KT OF EFFECTIVE SHEAR WILL SUPPORT
SOME SUPERCELLS WITH A MORE PREVALENT CONVECTIVE MODE OF SUSTAINED
MULTICELLS/LINE SEGMENTS WITH EMBEDDED BOWS. DAMAGING WINDS AND
SEVERE HAIL WILL BE POSSIBLE.

FARTHER NORTHEAST...AT LEAST ISOLATED SEVERE THUNDERSTORMS CAPABLE
OF DAMAGING WINDS/HAIL WILL BE POSSIBLE ACROSS PORTIONS OF THE
NORTHEAST STATES AND POSSIBLY SOUTHERN NEW ENGLAND TUESDAY
AFTERNOON/EVENING.

 

[A-L-E-K]

should be a nice line for south west/central WI into far northern/northwest IL

[Geos]

About 10 pm tonight. 6z 4km NAM.

 

 

11pm CST

 

[A-L-E-K]

timing is less than ideal but models are showing nice dCAPE, should still see decent gusts

[RCNYILWX]

New NAM 12km came in way too high with dew points ahead of the front this afternoon/early evening. Mid to upper 70s across northern IL and southern WI is not gonna happen, even if there's an assist from evapotranspiration from corn that wasn't flattened on Monday. Upper 60s-low 70s is probably where they'll be.

[wisconsinwx]

Probably will be some cloud debris with the decaying showers to the NW.

[Geos]

Sun has finally broken out here. Temperature rising into the upper 70s.

 

Definitely a lot of cloud debris over the Upper MS valley this morning.

 

[A-L-E-K]

New NAM 12km came in way too high with dew points ahead of the front this afternoon/early evening. Mid to upper 70s across northern IL and southern WI is not gonna happen, even if there's an assist from evapotranspiration from corn that wasn't flattened on Monday. Upper 60s-low 70s is probably where they'll be.

 

 

def too high but pwats, moisture transport and insolation all look pretty good for the time being…although some high debris is pushing into the NW.

[cyclone77]

Huge shield of clouds over much of Iowa and southern MN is gonna take a bite out of cape from the looks of things. 

[RCNYILWX]

def too high but pwats, moisture transport and insolation all look pretty good for the time being…although some high debris is pushing into the NW.

The mid and high cloud debris from the decaying MCS is probably the biggest uncertainty right now. MKX asked SPC on our internal chat about the impact of the cloud cover and SPC mentioned the severe threat likely being mainly confined to the frontal zone. This could tone down the overall severe threat some, so I wouldn't be surprised if the 30% wind and hatched hail are pulled with the 1630z, though they might hold onto it until the 20z update to further assess trends.

Edit: They did hold onto the 30% wind and hatched hail, and expanded the Slight Risk northeastward a good deal.

[Hoosier]

Slight risk expanded north and east on the 1630z outlook

[Chitown Storm]

77/74 here in St. Paul. The MCS died over the area earlier this morning. If the sun comes out in full, it's gonna get nasty. Clouds up here are thinning somewhat. Won't see the severe stuff here due to timing, but if the sun can break out it may help things downstream.

[Brewers]

High clouds continue to diminish quickly, but its going to take some time to mix out these low-level clouds.

[Gilbertfly]

Up in Jo Davies County today....you could feel the DP increasing last evening and spiking up quite a bit so far today...feels low 70's ish. Some of that could be owed to micro-climate via the crop growth around my current local as the sun has made some appearences in and out thus far this morning....fwiw

[A-L-E-K]

been mostly sunny all morning here

[Chicago WX]

Slight risk expanded north and east on the 1630z outlook

Day two expanded north a bit too, now includes us. Alas, has the feel that we'll be stuck in no man's land. I guess we'll see...

[The_Doctor]

We were getting some filtered sun but now the clouds have thickened up again

[Hoosier]

Day two expanded north a bit too, now includes us. Alas, has the feel that we'll be stuck in no man's land. I guess we'll see...

 

 

I'm not excited about tomorrow.  The better chance may be with whatever develops farther north today and survives overnight but not like I'm all that thrilled about those prospects either. 

[wisconsinwx]

I take it those storms in WC Wisconsin will likely constitute the main show today.

[Geos]

Clouded up completely here again. Struggling to make 80°.

[cyclone77]

Some beefy dews pooling ahead of the cold front over northern IA.  Storm Lake with a dew of 81.  Even in northeast IA at KOLZ they're at 77. 

[Chicago WX]

I'm not excited about tomorrow. The better chance may be with whatever develops farther north today and survives overnight but not like I'm all that thrilled about those prospects either.

Yeah, that's what I expected. Hope for some excitement tonight/overnight I guess...

[A-L-E-K]

feeling very sticky, still full sun

[A-L-E-K]

still full sun

[Geos]

Making progress on the destabilization now. Low 80s and mostly sunny skies.

[cyclone77]

SPC mesoanalysis showing 7500j/kg SBCAPE southeast of Sioux City IA.  Wow.

[hawkeye_wx]

There has been a thick shield of clouds across northeast Iowa all day, which has held the temp down to the upper 70s to low 80s.

[Chitown Storm]

Driving on 94 out of MN back to Chicago. Almost to Eau Claire. Currently 85/74 with almost full sun. Staring at the back of the storms firing ahead. Massive anvils. Could be a rough few hours.