June 16-25 Severe threat

[snowlover2]

New day 1

 

 

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 AM CDT MON JUN 16 2014

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF THE MID MO AND UPPER
MS VALLEYS EWD TO PARTS OF THE WRN GREAT LAKES...

...SUMMARY...
SEVERE THUNDERSTORMS PRODUCING DAMAGING WINDS...LARGE HAIL AND
TORNADOES WILL BE POSSIBLE ACROSS PORTIONS OF EASTERN SOUTH DAKOTA
AND NEBRASKA EASTWARD ACROSS MUCH OF IOWA...SOUTHERN MINNESOTA...AND
WISCONSIN FROM THE AFTERNOON INTO THE OVERNIGHT HOURS.
ELSEWHERE...ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE OVER
PORTIONS OF THE SOUTHEASTERN STATES...THE SOUTHERN PLAINS...AND
PARTS OF MONTANA.

...SYNOPSIS...
AN UPPER SPEED MAX OVER THE NRN GREAT BASIN SUNDAY EVENING IS
FORECAST TO MOVE TO THE UPPER GREAT LAKES REGION BY MONDAY EVENING.
A BROAD BELT OF MODERATE TO STRONG MID-LEVEL FLOW WILL EXTEND FROM
THE UPPER GREAT LAKES SWWD INTO THE SWRN CONUS AS AN UPSTREAM JET
STREAK MOVES INTO THE BASE OF A LARGER-SCALE TROUGH OVER THE WRN
STATES. IN THE LOW LEVELS...A WEAK SURFACE LOW WILL MIGRATE EWD
ALONG THE NEB/SD BORDER AS A WARM FRONT ADVANCES NWD ACROSS THE MID
MO RIVER VALLEY AND REACHES THE MN/IA BORDER REGION BY EARLY
EVENING. A DRYLINE WILL EXTEND SWD FROM CNTRL NEB INTO W TX.

...ERN HALVES OF SD/NEB EWD TO THE WRN GREAT LAKES...
STRONG LOW-LEVEL MOISTURE TRANSPORT NWD WILL BE ONGOING MONDAY
MORNING ON THE NOSE OF A 50 KT LLJ OVER THE CNTRL PLAINS.
CONSIDERABLE UNCERTAINTY REMAINS REGARDING THE POTENTIAL FOR EARLY
DAY STORM EVOLUTION AND ITS INFLUENCE ON THE PLACEMENT OF THE
EFFECTIVE WARM FRONT AND/OR OUTFLOW BOUNDARY. DESPITE THESE
CONCERNS...STEEP MID-LEVEL LAPSE RATES IN EXCESS OF 8 DEG C PER KM
ATOP MID-UPPER 60S BOUNDARY LAYER DEWPOINTS WILL LIKELY RESULT IN A
VERY UNSTABLE AIRMASS /MLCAPE 3000 J/KG OR GREATER/ TO THE E OF THE
DRYLINE...S OF THE WARM FRONT...AND ANY EARLY DAY CONVECTIVE
OUTFLOW. THE FOCUSING OF THE LLJ INTO ERN NEB/SD AND SRN MN/NRN IA
DURING THE DAY WILL LEAD TO LARGE HODOGRAPHS...ESPECIALLY NEAR THE
WARM FRONT. DIURNALLY-GENERATED SCTD STORMS AND 40-50 KT EFFECTIVE
SHEAR WILL INCLUDE THE POSSIBILITY FOR INTENSE SUPERCELLS YIELDING A
LARGE TO VERY LARGE HAIL/WIND THREAT AND THE POTENTIAL FOR A FEW
TORNADOES /SOME PERHAPS SIGNIFICANT/. THE APPROACH OF A 50 KT H7
WIND MAXIMUM DURING THE EVENING AND OVERNIGHT WILL SUPPORT AN
ORGANIZED WIND DAMAGE THREAT AS ACTIVITY GROWS UPSCALE AND MOVES EWD
TOWARDS THE WRN GREAT LAKES.

 

 

[snowlover2]

New day 2

 

 

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1218 AM CDT MON JUN 16 2014

VALID 171200Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE NRN
PLAINS...UPPER MS VALLEY...AND UPPER GREAT LAKES...

...SUMMARY...
ISOLATED TO SCATTERED STORMS PRODUCING WIND AND HAIL WILL BE
POSSIBLE FROM THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES WESTWARD
ACROSS THE NORTHERN PLAINS.

...SYNOPSIS...
THE PRESENCE OF A SLOW-MOVING UPPER LOW OVER THE NRN ROCKIES WILL
MAINTAIN MODEST SWLY FLOW ALOFT ACROSS THE NRN AND CNTRL
PLAINS...WITH AN UPPER HIGH CENTERED OVER TN. SUBSTANTIAL MOISTURE
AND INSTABILITY WILL REMAIN ACROSS THE NRN PLAINS DUE TO SLY SURFACE
WINDS WITH LOW PRESSURE FROM NEB INTO ERN WY THROUGH THE PERIOD. THE
MEAN SYNOPTIC FRONT WILL GENERALLY EXTEND FROM NERN WY EWD ACROSS SD
AND INTO SRN MN/NRN IA...AND WILL BE A FOCUS FOR STRONG TO SEVERE
STORMS. A COLD FRONT OVER ERN MT WILL ALSO BE A FOCUS FOR SEVERE
WEATHER BY LATE IN THE DAY AND ACROSS THE WRN DAKOTAS BY EVENING.

ELSEWHERE...A LEADING SHORTWAVE DISTURBANCE WILL MOVE EWD ACROSS THE
GREAT LAKES INTO THE NERN STATES BY WED EVENING...WITH A WLY INFLUX
OF UNSTABLE AIR RESULTING IN A FEW STRONG THUNDERSTORMS THERE.

...WI EARLY...LOWER MI...NY...
AN MCS MAY BE ONGOING TUE MORNING ACROSS SERN WI AND PERHAPS FAR NRN
IL ON THE NOSE OF A SWLY LOW-LEVEL JET. AMPLE CAPE AND FAVORABLE
MEAN WINDS SUGGEST A DAMAGING WIND THREAT. THESE STORMS WOULD LIKELY
PERSIST ACROSS LOWER MI...AIDED BY AREAS OF HEATING. LATER IN THE
EVENING AND OVERNIGHT...STORMS MAY RE-EMERGE ACROSS THE U.S. BORDER
INTO NY...BUT SEVERE POTENTIAL IS DEPENDENT ON WHAT FORMS UPSTREAM.

...ERN DAKOTAS...MN...IA...WI...
A COMPLICATED FORECAST SCENARIO WILL PLAY OUT FROM THE DAKOTAS INTO
THE UPPER MS VALLEY DURING THE DAY WITH DEVELOPMENT POSSIBLE
ANYWHERE ALONG THE FRONT. INSTABILITY AND SHEAR PROFILES WILL BE
FAVORABLE FOR LARGE HAIL AND DAMAGING WINDS...WITH PERHAPS A FEW
TORNADOES IF STORM MODE REMAINS CELLULAR. HOWEVER...THE GREATEST
SIGNAL FOR AN ORGANIZED SEVERE STORM THREAT IS DURING THE EVENING
ACROSS MUCH OF SRN MN...IA...AND WI NEAR THE WARM FRONT AND WHERE IT
WILL BE MOST UNSTABLE. WHATEVER FORMS IN MN/WI COULD PROPAGATE SWD
ACROSS NERN IA AND NRN IL OVERNIGHT WITH DAMAGING WINDS AND HAIL.

 

[snowlover2]

New Day 3

 

 

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0224 AM CDT MON JUN 16 2014

VALID 181200Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN PLAINS AND UPPER
MS VALLEY EASTWARD INTO PA...

...SUMMARY...
SEVERE THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE NORTHERN AND
CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY...AND FROM LOWER
MICHIGAN EASTWARD INTO PENNSYLVANIA. ISOLATED SEVERE STORMS ARE ALSO
POSSIBLE FROM WESTERN KANSAS INTO WEST TEXAS. LARGE HAIL AND
DAMAGING WINDS WILL BE THE MAIN THREATS...WITH THE MOST SIGNIFICANT
SEVERE ACROSS THE DAKOTAS AND MINNESOTA.

...SYNOPSIS...
AN AMPLIFIED UPPER TROUGH IS FORECAST TO EMERGE ACROSS THE CNTRL AND
NRN HIGH PLAINS LATE ON WED...ALTHOUGH THE ECMWF IS A BIT SLOWER AND
KEEPS THE THERMAL GRADIENT ALOFT FARTHER W THAN THE GFS OR NAM.
STILL...MERIDIONAL FLOW ALOFT WILL OVERSPREAD THE REGION...WITH A
LOW PRESSURE TROUGH DEVELOPING FROM SD SWD INTO THE CNTRL HIGH
PLAINS. SELY LOW-LEVEL WINDS WILL MAINTAIN SUBSTANTIAL MOISTURE AND
INSTABILITY OVER MUCH OF THE UPPER MS VALLEY WWD TOWARD THE SFC
TROUGH.

TO THE E...MODELS INDICATE A SHORTWAVE DISTURBANCE MAY AFFECT THE
LOWER MI TO PA CORRIDOR...WHERE IT WILL BE SUFFICIENTLY MOIST AND
UNSTABLE FOR STRONG TO SEVERE STORMS.

...ERN DAKOTAS...MN...NEB...IA...WRN WI...
AREAS OF STORMS MAY BE ONGOING OR FORM RELATIVELY EARLY IN THE DAY
ACROSS SRN MN/IA DUE TO RAPID MOISTURE ADVECTION AS 850 MB FLOW
BACKS AND INCREASES IN RESPONSE TO THE DEEPENING LOW. THESE STORMS
COULD POSE A LOCALIZED WIND/HAIL THREAT. THE GREATEST THREAT OF
SEVERE SHOULD MATERIALIZE OVER ND AND NRN SD BY LATE AFTERNOON
COINCIDENT WITH THE STRONGEST LIFT NEAR THE PRESSURE TROUGH/COLD
FRONT. THIS FRONT IS NOT EXPECTED TO MOVE QUICKLY...AND WITH BACKED
LOW-LEVEL FLOW...SUPERCELLS MAY FORM IN THIS AREA WITH LARGE HAIL
AND A FEW TORNADOES. WITH TIME...INCREASING LIFT FROM WARM ADVECTION
SHOULD LEAD TO A SEWD-MOVING MCS ACROSS MN AND SD...WITH OTHER
ACTIVITY DEVELOPING ALONG THE SURGING COLD FRONT INTO NEB WITH WIND
AND HAIL.

...LOWER MI AND OH EWD INTO PA...
A RIBBON OF LOW-LEVEL MOISTURE WILL BE MAINTAINED FORM THE MIDWEST
EWD ACROSS THE OH VALLEY WITH WLY SFC FLOW AND A WEAK SFC TROUGH.
MODELS INDICATE A SHORTWAVE DISTURBANCE TRAVELING FROM LOWER MI INTO
PA DURING THE DAY...ON SRN PERIPHERY OF THE UPPER LOW OVER QUEBEC.
THIS SUGGESTS THERE WILL BE A CORRIDOR OF MCS ACTIVITY...WITH
DAMAGING WINDS POSSIBLE. INSTABILITY WILL BE SUFFICIENT...BUT NOT
EXTREME...THUS SIGNIFICANT SEVERE IS NOT ANTICIPATED. UNIDIRECTIONAL
PROFILES ALOFT ALSO SUGGEST THAT THE TORNADO THREAT SHOULD BE
LOW...BUT COOL TEMPERATURES ALOFT WOULD STILL FAVOR MARGINALLY
SEVERE HAIL.

 

 

[A-L-E-K]

nice overnight afd from LOT, timing isn't favorable for severe IMBY but i like my chances for a few convective complexes over the week

[hawkeye_wx]

Sioux-land across northern IA has been upgraded to moderate risk.  There is already a line of strong to severe storms across eastern Nebraska.  For my area it's mostly just a waiting game to see how the storms evolve through the day.  The models are not very helpful.

[RyanDe680]

Didn't someone post a couple of days ago a derecho heading out of IA/MN eastward overnight tonight?

[A-L-E-K]

Didn't someone post a couple of days ago a derecho heading out of IA/MN eastward overnight tonight?

 

 

naso sure about derecho but we should see a decent complex survive the night across S. WI

 

I think a case can be made for some back building into LOT's northern CWA

[wisconsinwx]

naso sure about derecho but we should see a decent complex survive the night across S. WI

 

I think a case can be made for some back building into LOT's northern CWA

 

I hope it survives overnight, it will probably not arrive at Lake Michigan until close to 12z, but by then the southerly winds will be back pumping in the moist air after a lake component this afternoon and evening, so that should help.

[A-L-E-K]

I hope it survives overnight, it will probably not arrive at Lake Michigan until close to 12z, but by then the southerly winds will be back pumping in the moist air after a lake component this afternoon and evening, so that should help.

 

nocturnal LLJ looks healthy so the southern edge (wherever it ends up) should be able maintain somewhat despite unfavorable timing.

[cyclone77]

If the complex over eastern SD and eastern NE merges, as it looks like it will, we might not have to wait until late tonight for severe potential.  It looks like that thing could traverse much of Iowa and southern MN during the afternoon, and cross the Mississippi by early evening.  Don't see any reason why that complex would die out before reaching areas east of the Mississippi, as it will have access to plenty of cape and decent bulk shear. 

 

I sure hope I don't jinx it like I did yesterday lol. 

[wisconsinwx]

If the complex over eastern SD and eastern NE merges, as it looks like it will, we might not have to wait until late tonight for severe potential.  It looks like that thing could traverse much of Iowa and southern MN during the afternoon, and cross the Mississippi by early evening.  Don't see any reason why that complex would die out before reaching areas east of the Mississippi, as it will have access to plenty of cape and decent bulk shear. 

 

I sure hope I don't jinx it like I did yesterday lol. 

 

Yeah, based on the models it looked like that complex in E Nebraska may end up being the one initially modeled, in which case timing would be earlier than indicated by the majority of models.

[A-L-E-K]

initialization is poor, I wouldn't put too much stock in the models period.

 

gonna have to watch for cold pool development and see if these things can turn southeast into more unstable air later this evening.

[wisconsinwx]

initialization is poor, I wouldn't put too much stock in the models period.

 

gonna have to watch for cold pool development and see if these things can turn southeast into more unstable air later this evening.

 

That being said the GFS Ensembles actually had a pretty good handle on location of this morning convection in E Nebraska and E South Dakota.

[A-L-E-K]

THIS EVENING...A LOW LEVEL JET IS PROGGED TO DEVELOP AHEAD OF AN
APPROACHING LOW KICKING OFF THUNDERSTORMS WHICH WILL INCREASE IN
COVERAGE. MOST GLOBAL MODELS SHOW THE BULK OF THE ACTIVITY STAYING
OVER WISCONSIN...HOWEVER THERE ARE HINTS THAT SOME OF THESE STORMS
COULD PROPAGATE SOUTH INTO NORTHERN ILLINOIS IMPACTING THE TERMINALS
LATE THIS EVENING AND OVERNIGHT. WILL MAINTAIN A PROB30 FOR NOW
GIVEN THE LACK OF CERTAINTY IN THIS SCENARIO PANNING OUT. HI-RES
GUIDANCE IS ALL OVER THE PLACE AND OFFERS LITTLE INSIGHT INTO HOW
CONVECTION MIGHT EVOLVE THIS EVENING AND TONIGHT.
 

[A-L-E-K]

there is a pocket of drier air around LaCrosse and the best airmass is confined well south, so i'm having a hard time buying into model solutions showing convective bullseyes so far north.

[Hoosier]

Powderkeg stuff tomorrow

 

 

[A-L-E-K]

gonna be very interesting to see just how far south the outflow boundary gets from tonight's action...hard to get into details tomorrow without that detail

[Hoosier]

gonna be very interesting to see just how far south the outflow boundary gets from tonight's action...hard to get into details tomorrow without that detail

 

 

Agree

[Hoosier]

Moderate and slight risk areas were expanded a bit east on the 1630z outlook.  The moderate is now into far southwestern WI.

 

[A-L-E-K]

baby steps

[A-L-E-K]

LOT agrees with my thinking

 

THE FORECAST FOR TONIGHT REMAINS TRICKY. CONVECTION NEAR THE NE/IA
BORDER IS PRIMARILY ELEVATED AND NOT REALLY CONGEALING OR BECOMING
ROOTED LOWER AT THIS TIME...ALTHOUGH MAY BECOME A LITTLE MORE
FAVORABLE IN TIME /SEE SPC MCD/. UPSCALE GROWTH IS EXPECTED INTO
SOUTHERN MN WITH EVENTUAL CONGEALING INTO AN MCS THIS EVE INTO
OVERNIGHT...WHICH A HIGH AMOUNT OF CONVECTIVE-ALLOWING GUIDANCE
SHOWS. WHILE MUCH OF THE GUIDANCE DOES BRING THE BRUNT OF THAT
NORTH OF THE AREA...THE PATTERN...SLOPE OF THE INSTABILITY
GRADIENT...AND OBSERVATIONAL TRENDS WOULD INDICATE THAT MAYBE THE
SUITE OF GUIDANCE IS TOO FAR NORTH...AND AT LEAST THE SOUTHERN
PORTION OF THE COMPLEX...OR WHAT BACKBUILDS AGAINST THE LOW-
LEVEL JET NOSE WOULD EVOLVE INTO FAR NORTHERN IL LATE TONIGHT.
 

[wisconsinwx]

LOT agrees with my thinking

 

THE FORECAST FOR TONIGHT REMAINS TRICKY. CONVECTION NEAR THE NE/IA

BORDER IS PRIMARILY ELEVATED AND NOT REALLY CONGEALING OR BECOMING

ROOTED LOWER AT THIS TIME...ALTHOUGH MAY BECOME A LITTLE MORE

FAVORABLE IN TIME /SEE SPC MCD/. UPSCALE GROWTH IS EXPECTED INTO

SOUTHERN MN WITH EVENTUAL CONGEALING INTO AN MCS THIS EVE INTO

OVERNIGHT...WHICH A HIGH AMOUNT OF CONVECTIVE-ALLOWING GUIDANCE

SHOWS. WHILE MUCH OF THE GUIDANCE DOES BRING THE BRUNT OF THAT

NORTH OF THE AREA...THE PATTERN...SLOPE OF THE INSTABILITY

GRADIENT...AND OBSERVATIONAL TRENDS WOULD INDICATE THAT MAYBE THE

SUITE OF GUIDANCE IS TOO FAR NORTH...AND AT LEAST THE SOUTHERN

PORTION OF THE COMPLEX...OR WHAT BACKBUILDS AGAINST THE LOW-

LEVEL JET NOSE WOULD EVOLVE INTO FAR NORTHERN IL LATE TONIGHT.

 

 

You're right, interestingly though MKX favors keeping the brunt of the complex even north of Milwaukee.  Looking at the reality of the current storms, I envision the WI/IL border region and just north/south bearing the brunt once it starts moving ESE/SE.

[A-L-E-K]

You're right, interestingly though MKX favors keeping the brunt of the complex even north of Milwaukee.  Looking at the reality of the current storms, I envision the WI/IL border region and just north/south bearing the brunt once it starts moving ESE/SE.

 

 

it won't happen until the early morning hours anyways, the implications for tomorrow are more interesting at this point

[A-L-E-K]

earlier NE complex is in the process of merging with the SD complex (almost looks like a WAA wing in the making) and the whole complex should continue to the east across far southern MN before heading more SE

 

couple of decent storms heading into DVN's cwa as well

[cyclone77]

So much for the complex coming out of western Iowa this afternoon.  Those storms crapped out.  Looks like the complex will end up being late tonight after all for areas east of the MS river. 

[wisconsinwx]

So much for the complex coming out of western Iowa this afternoon.  Those storms crapped out.  Looks like the complex will end up being late tonight after all for areas east of the MS river. 

 

I think cloud cover and even some stratiform rain ahead of the actual individual storms stabilized much of the western half to two-thirds of Iowa just enough to allow it to crap out.

[A-L-E-K]

storms along the effective warm front in IA/IL worth watching, especially if they develope a cold pool.

[A-L-E-K]

THE STRONG UPPER JET AND ASSOCIATED SHORT WAVE...MAYBE EVEN
MULTIPLE WAVES PER WATER VAPOR...WILL YIELD A LIKELY MCS ACROSS
OR NEAR THE MN/IA BORDER GIVEN MCS PARAMETERS IN PLACE. WITH THE
STRONG MOISTURE AND INSTABILITY FEED VEERING AHEAD OF IT AND WITH
ITS OWN COLD POOL DEVELOPMENT...THERE SHOULD BE A MORE RAPID
PROGRESSION THROUGH LATER EVE INTO OVERNIGHT. WHICH WAY THIS
PROGRESSES HAS BEEN SOMETHING THAT MODELS HAVE GRADUALLY STARTED
TO TREND MORE SOUTH WHICH AGREES WITH EARLIER THINKING AND MAKES
SENSE WITH 1. THE NORTHWEST-TO-SOUTHEAST SLOPING INSTABILITY
GRADIENT 2. THIS GRADIENT KEEPING THAT ORIENTATION ACROSS
WESTERN/CENTRAL IL DUE TO ONGOING CONVECTION AND 3. THE 850-300MB
THICKNESSES/FLOW REMAINING EAST-SOUTHEAST ORIENTED. BECAUSE OF
THIS HAVE INCREASED POPS ACROSS THE NORTHERN FORECAST AREA WITH
LIKELIES...ESPECIALLY AFTER 2 AM. WHETHER THE MCS SEVERE WIND
POTENTIAL DIMINISHES AS IT NEARS THE WI/IL BORDER...THERE STILL
WILL LIKELY BE SOME BACKBUILDING ON ITS SOUTHERN END TOWARD THE
INSTABILITY AND GIVEN ANGLE OF BACKWARD PROGRESSING CORFIDI
VECTORS. NUMEROUS CONVECTIVE ALLOWING MODELS INDICATE THIS WITH
CELLULAR DEVELOPMENT ON THE SOUTH SIDE...THAT COULD BRING MORE OF
A HEAVY RAIN THREAT...ALONG WITH POTENTIAL FOR HAIL. SO AS THE SPC
OUTLOOK SHOWS...THE SEVERE WEATHER THREAT IS HIGHEST TO OUR
NORTHWEST BUT DOES SLOPE INTO OUR AREA...WITH WINDS BEING THE
GREATEST...ESPECIALLY IF THE COLD POOL IS CONTINUING TO DRIVE THE
SYSTEM.
 

[Powerball]

What a mess of a setup...

[wisconsinwx]

Interestingly enough, Northern Indiana's WFO disagrees with Alek and LOT:

 

 

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 354 PM EDT MON JUN 16 2014

MAIN FOCUS FOR THE SHORT TERM WILL BE CONVECTIVE TRENDS THROUGH THE
PERIOD. SHORT WAVE WHICH WAS RESPONSIBLE FOR SCATTERED SHOWERS
ACROSS NORTHEAST INDIANA EARLY TODAY HAS MOVED OFF TO THE EAST.
THIS HAS RESULTED IN SOME WEAK MID LEVEL SUBSIDENCE THIS
AFTERNOON IN ITS WAKE. LITTLE IN THE WAY OF ADDITIONAL SYNOPTIC
FORCING MECHANISMS ARE EXPECTED FOR THE REMAINDER OF THE AFTERNOON
WITH DRY CONDITIONS EXPECTED.

CONVECTION HAS DEVELOPED ACROSS WEST CENTRAL AND PORTIONS OF CENTRAL
ILLINOIS IN SUBTLE WARM FRONTAL ZONE...WITH CO-LOCATION OF 100
HPA MIXED LAYER CAPES ON THE ORDER OF 3000-3500 J/KG. THIS ZONE OF
LOW LEVEL WARM ADVECTION SHOULD REACH INTO NORTHEAST
ILLINOIS/NORTHWEST INDIANA LATER THIS EVENING AND INTO THE
OVERNIGHT...ALTHOUGH DIURNAL DIMINISHMENT OF SURFACE BASED
INSTABILITY WILL LIKELY LIMIT CONVECTIVE CHANCES WITH THIS WARM
ADVECTION FOR LOCAL AREA. DID MAINTAIN SLIGHT CHANCE POPS ACROSS
THE NORTHWEST WITH LOW PROBABILITY OF ISOLATED STORMS DEVELOPING
IN ASSOCIATION WITH THIS WAA FORCING LATE EVENING.

THE HIGHER CHANCES OF PRECIP SHOULD OCCUR LATE TONIGHT AND INTO
TUESDAY. SYNOPTIC SETUP WOULD APPEAR TO FAVOR FORWARD PROPAGATION
OF EASTERN SOUTH DAKOTA MCS INTO THE GREAT LAKES REGION OVERNIGHT.
FORWARD PROPAGATING CORFIDI VECTORS WOULD APPEAR TO FAVOR MORE OF A
EAST/NORTHEAST PROPAGATION TO ANY MCS TO THE NORTH. HOWEVER...WOULD
EXPECT AS POTENTIAL MCS BEGINS TO OUTRUN GREATER INSTABILITY TOWARD
MORNING...SOME TENDENCY FOR UPWIND PROPAGATION MAY INCREASE DUE TO
GREATER ELEVATED INSTABILITY TO SOUTH...AND PRESENCE OF ROBUST LOW
LEVEL JET. SOME POTENTIAL MAY ALSO EXIST FOR SOME SCATTERED SHOWERS
AND STORMS TO DEVELOP ON OUTFLOWS DRIVEN SOUTHWARD FROM GREAT LAKES
CONVECTION BY TUESDAY MORNING. GIVEN UNCERTAINTY WITH THIS
SETUP...FELT IT WAS APPROPRIATE AT THIS TIME TO MAINTAIN MID TO HIGH
CHANCE TSRA POPS OVERNIGHT INTO TUESDAY MORNING...MAINLY ACROSS THE
NORTH. NOT CURRENTLY EXPECTING MUCH IN THE WAY OF SEVERE THREAT
TONIGHT/EARLY TUESDAY MORNING WITH INSTABILITY RELATIVELY WEAK IN
NATURE AND ELEVATED.

DETAILS IN TUESDAYS FORECAST STILL SOMEWHAT OF LOW CONFIDENCE AT
THIS TIME DUE TO DEPENDENCE OF OVERNIGHT CONVECTION ON MESOSCALE
DETAILS. SOME INDICATION IN LATEST MODEL DATA THAT PASSAGE OF
CONVECTIVELY ENHANCED VORT MAX TUESDAY MORNING MAY BE FOLLOWED BY
VERY WEAK MID LEVEL HEIGHT RISES ONCE AGAIN. FORECAST SOUNDINGS ALSO
SUGGEST EASTWARD ADVECTION OF EML INTO THE REGION DURING THE
AFTERNOON POSING CAPPING CONCERNS. DID MAINTAIN HIGHEST CHANCE POPS
IN THE MORNING BEFORE STRONG CAPPING LIKELY ENSUES. CANNOT DISCOUNT
ISOLD SEVERE THREAT GIVEN VERY UNSTABLE CONDITIONS AND MODEST DEEP
LAYER SHEAR ACROSS THE NORTH. LIMITING FACTORS FOR SEVERE POTENTIAL
TUESDAY WILL BE AFOREMENTIONED CAPPING CONCERNS AND DIMINISHING
SYNOPTIC FORCING IN THE AFTERNOON. WAA TONIGHT WILL LEAD TO HOT
CONDITIONS ON TUESDAY WITH HIGHS INTO THE LOWER 90S
EXPECTED...ALTHOUGH POSSIBLY TEMPERED A BIT ACROSS THE NORTH DUE
TO RESIDUAL EFFECTS FROM OVERNIGHT/MORNING CONVECTION. SOUTH WINDS
TO ALSO BECOME GUSTY INTO THE 20 TO 30 MPH RANGE TUESDAY
AFTERNOON.