October 25 - 26 Plains/MW/OV/GL Severe Weather, SPC Risk Level: Day 1 See Text Options

[melissa from ill...]

NICE! Summer just wont give up.

CODE

DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1211 PM CDT MON OCT 24 2011
  
   VALID 251200Z - 261200Z
  
   ...NO SVR TSTM AREAS FORECAST...
  
   ...MID MS VALLEY...
  
   CENTRAL PLAINS SFC CYCLONE IS EXPECTED TO SHEAR EWD AND GRADUALLY
   WEAKEN AS LARGE SCALE FORCING OVERSPREADS THE MID MS/OH VALLEY
   REGION.  STRONG LOW LEVEL WARM ADVECTION EARLY IN THE PERIOD WILL BE
   FOCUSED ACROSS MN/WI WHICH SHOULD DRIVE ELEVATED CONVECTION ACROSS
   PORTIONS OF THE SRN GREAT LAKES.  MEAGER INSTABILITY WILL PRECLUDE
   ANY MEANINGFUL THREAT OF LARGE HAIL WITH THIS ACTIVITY.
   HOWEVER...STRONG HEATING ALONG TRAILING COLD FRONT ACROSS CNTRL
   IL/MO WILL ALLOW LOW LEVEL LAPSE RATES TO STEEPEN AND FRONTAL
   CONVECTION IS EXPECTED TO INTENSIFY DURING THE LATE AFTERNOON HOURS
   WHEN MUCAPE WILL BE MAXIMIZED ALONG ADVANCING WIND SHIFT.  EVEN SO
   IT APPEARS INSTABILITY WILL STRUGGLE TO SUPPORT ORGANIZED SEVERE
   TSTMS.  ATTM IT APPEARS 500-1000 J/KG CAPE COULD RESULT IN A FEW
   ROBUST STORMS CAPABLE OF GENERATING MARGINALLY SEVERE HAIL OR
   PERHAPS GUSTY WINDS.
  
   ...SWRN U.S...
  
   MUCH COOLER MID LEVEL TEMPERATURES WILL OVERSPREAD THE CNTRL ROCKIES
   AS HEIGHTS FALL WITHIN THE BASE OF DIGGING WRN U.S. TROUGH.
   ISOLATED THUNDERSTORMS SHOULD EASILY DEVELOP WITHIN FAVORABLE SWLY
   FLOW REGIME ACROSS THE FAVORED HIGHER TERRAIN FROM SRN UT/SWRN CO
   INTO PORTIONS OF NERN AZ/NWRN NM.

[jdrenken]

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1211 PM CDT MON OCT 24 2011

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...MID MS VALLEY...

CENTRAL PLAINS SFC CYCLONE IS EXPECTED TO SHEAR EWD AND GRADUALLY
WEAKEN AS LARGE SCALE FORCING OVERSPREADS THE MID MS/OH VALLEY
REGION. STRONG LOW LEVEL WARM ADVECTION EARLY IN THE PERIOD WILL BE
FOCUSED ACROSS MN/WI WHICH SHOULD DRIVE ELEVATED CONVECTION ACROSS
PORTIONS OF THE SRN GREAT LAKES. MEAGER INSTABILITY WILL PRECLUDE
ANY MEANINGFUL THREAT OF LARGE HAIL WITH THIS ACTIVITY.
HOWEVER...STRONG HEATING ALONG TRAILING COLD FRONT ACROSS CNTRL
IL/MO WILL ALLOW LOW LEVEL LAPSE RATES TO STEEPEN AND FRONTAL
CONVECTION IS EXPECTED TO INTENSIFY DURING THE LATE AFTERNOON HOURS
WHEN MUCAPE WILL BE MAXIMIZED ALONG ADVANCING WIND SHIFT. EVEN SO
IT APPEARS INSTABILITY WILL STRUGGLE TO SUPPORT ORGANIZED SEVERE
TSTMS. ATTM IT APPEARS 500-1000 J/KG CAPE COULD RESULT IN A FEW
ROBUST STORMS CAPABLE OF GENERATING MARGINALLY SEVERE HAIL OR
PERHAPS GUSTY WINDS.

...SWRN U.S...

MUCH COOLER MID LEVEL TEMPERATURES WILL OVERSPREAD THE CNTRL ROCKIES
AS HEIGHTS FALL WITHIN THE BASE OF DIGGING WRN U.S. TROUGH.
ISOLATED THUNDERSTORMS SHOULD EASILY DEVELOP WITHIN FAVORABLE SWLY
FLOW REGIME ACROSS THE FAVORED HIGHER TERRAIN FROM SRN UT/SWRN CO
INTO PORTIONS OF NERN AZ/NWRN NM.

..DARROW.. 10/24/2011

[melissa from ill...]

Thanks Joe for starting the thread for me. Ive never started a new thread before.

[jdrenken]

Latest Day 1

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CDT TUE OCT 25 2011

VALID 251300Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MAIN PORTION OF POSITIVE TILT TROUGH OVER THE NWRN U.S. WILL AMPLIFY
SE INTO THE WRN GRT BASIN THIS PERIOD...WHILE THE NRN PART MOVES
GENERALLY E FROM MT TO NRN MN. AS THIS OCCURS...A SERIES OF WEAKER
DISTURBANCES WILL FURTHER WEAKEN AS THEY CONTINUE ENE IN RESULTING
WSWLY CONFLUENT FLOW OVER THE CNTRL PLNS/MID MS VLY.

AT LWR LVLS...SFC LOW NOW OVER NEB...ASSOCIATED WITH LEAD IMPULSE IN
THE CONFLUENT WSWLY FLOW...SHOULD SLOWLY FILL AS IT CONTINUES ENE
INTO SRN MI BY 12Z WED. ITS TRAILING COLD FRONT SHOULD REACH A
STL-TUL-SPS LINE BY THAT TIME.

...KS/NRN OK ENE INTO MO/IL/IND/OH TODAY/TNGT...
CURRENT OBSERVATIONS SUGGEST THAT MOISTURE RETURN WILL REMAIN
LIMITED THROUGH TNGT AHEAD OF AFOREMENTIONED COLD FRONT OVER THE
SRN/CNTRL PLNS E/NE INTO THE MID MS/LWR OH VLYS. LOW LVL LAPSE
RATES ALSO WILL REMAIN RATHER WEAK...WITH A WARM LAYER CENTERED NEAR
800 MB LIKELY PROHIBITING SFC-BASED STORM DEVELOPMENT THROUGH THE
DAY. HOWEVER...SCTD ELEVATED STORMS LIKELY WILL SPREAD E FROM ERN
IA/NE MO INTO PARTS OF IL/IND AND MI THROUGH THE DAY IN ASSOCIATION
WITH 850-700 MB WAA.

SCTD SFC OR NEAR SFC-BASED STORMS MAY FORM BY EARLY EVE OVER CNTRL
AND NRN IL IN ZONE OF STRONGEST LOW LVL ASCENT NEAR SFC LOW.
RELATIVELY COOL MID LVL TEMPS AND STRONG...UNIDIRECTIONAL CLOUD
LAYER FLOW MAY YIELD SMALL TO MARGINALLY SVR HAIL IN SOME STORMS.
40 KT MEAN LWR TROPOSPHERIC WINDS ALSO COULD POSE A THREAT FOR ISOLD
STRONG SFC GUSTS. THE TSTMS SHOULD MOVE/DEVELOP EWD INTO IND AND OH
OVERNIGHT...WITH A CONTINUED LOW PROBABILISTIC SVR THREAT.

FARTHER SW...FORCING FOR ASCENT WILL BE WEAKER THAN IN THE MID MS
VLY...AND LIKELY FOCUSED ALONG/BEHIND SE-MOVING COLD FRONT. WEAK
MID LVL COOLING/ASCENT ASSOCIATED WITH ADDITIONAL SHORTWAVE
DISTURBANCES...ESPECIALLY TNGT...MAY SUPPORT A SMALL CLUSTER OR TWO
OF ELEVATED STORMS WITH HAIL FROM NRN OK INTO PARTS OF KS AND
WRN/SRN MO. THIS ACTIVITY COULD PERSIST OVER THE AREA THROUGH EARLY
WED.

...NRN AZ...
MODERATELY STRONG WSW UPR FLOW AND FAIRLY STEEP MID LVL LAPSE RATES
WILL OVERSPREAD AZ LATER TODAY AHEAD OF AMPLIFYING TROUGH. LOW LVL
SWLY UPSLOPE FLOW MAY FOSTER SCTD AFTN TSTMS ON THE RIM...AND
PERHAPS A FEW INSTANCES OF MAINLY SUB-SVR HAIL.

..CORFIDI/GARNER.. 10/25/2011

[jdrenken]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1106 AM CDT TUE OCT 25 2011

VALID 251630Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...KS/NRN OK ENE INTO MO/IL/IND/OH...

CHANGES TO PREVIOUS OUTLOOK INCLUDE: 1/REDUCING COVERAGE OF MRGL SVR
WIND PROBABILITIES OVER THE MIDWEST. 2/ SPLITTING LOW-END SVR HAIL
RISKS WITH ONE AREA OVER THE MIDWEST AND ANOTHER CONFINED TO THE SRN
PLAINS.

WEAK LOW-LEVEL LAPSE RATES AND MEAGER MOISTURE RETURN ALONG A SEWD
MOVING CDFNT WILL LIMIT SVR PROBABILITIES...BUT BE SUFFICIENT FOR
SPORADIC TSTMS...PARTICULARLY OVER THE MIDWEST THIS EVENING. 12Z
SOUNDINGS SUGGEST SUBSTANTIAL WARM/DRY LAYER JUST ABOVE 900 MB
FARTHER SW INTO THE OZARKS...WHICH WILL LIKELY BE MITIGATING FACTOR
IN SUSTAINED CONVECTION OVER THAT REGION.

OVER THE MIDWEST...NEAR SFC-BASED STORMS WILL FORM EARLY THIS EVE
OVER CNTRL AND NRN IL IN ZONE OF STRONGEST LOW LVL ASCENT NEAR SFC
LOW. RELATIVELY COOL MID LVL TEMPS AND STRONG...UNIDIRECTIONAL
CLOUD LAYER FLOW MAY YIELD SMALL TO MARGINALLY SVR HAIL IN SOME
STORMS. 40 KT MEAN LWR TROPOSPHERIC WINDS ALSO COULD POSE A THREAT
FOR ISOLD STRONG SFC GUSTS. THE TSTMS SHOULD MOVE/DEVELOP EWD INTO
IND AND OH OVERNIGHT...WITH A CONTINUED LOW PROBABILISTIC SVR
THREAT.

FARTHER SW...WEAK MID LVL COOLING/ASCENT ASSOCIATED WITH ADDITIONAL
SHORTWAVE DISTURBANCES...ESPECIALLY TNGT...MAY SUPPORT A SMALL
CLUSTER OR TWO OF ELEVATED STORMS WITH HAIL FROM NRN OK INTO PARTS
OF KS.

[jdrenken]

MESOSCALE DISCUSSION 2272
NWS STORM PREDICTION CENTER NORMAN OK
0656 PM CDT TUE OCT 25 2011

AREAS AFFECTED...PORTIONS NERN MO...EXTREME SERN IA...WRN/NRN IL.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 252356Z - 260230Z

TSTMS ARE DEVELOPING OVER WRN PORTIONS DISCUSSION AREA AND WILL MOVE
EWD WITH INCREASING COVERAGE THROUGH 02Z. 3-4 HOUR WINDOW APPEARS
MOST PROBABLE FOR THREAT OF OCNL/ISOLATED SVR HAIL BEGINNING SHORTLY
AFTER 00Z.

23Z SFC MESOANALYSIS SHOWS FRONTAL-WAVE LOW OVER NERN IA...FCST TO
MOVE EWD OVER IL/WI BORDER REGION THROUGH REMAINDER EVENING...WHILE
TRAILING SFC COLD FRONT MOVES SEWD ACROSS SERN IA AND N-CENTRAL MO.
PRE COLD-FRONTAL CONFLUENCE LINE WAS DRAWN FROM WARM-FRONTAL
INTERSECTION NEAR RFD SWWD ACROSS QUAD CITIES AREA THEN CURVING SWD
ACROSS CLARK COUNTY MO TO NEAR COU. THIS BOUNDARY SHOULD CONTINUE
TO REPRESENT WRN BOUND OF MOST DEVELOPMENT POTENTIAL...WITH
CONVERGENCE REINFORCED ONCE FRONT CATCHES CONFLUENCE LINE DURING
02Z-04Z PERIOD. MOISTURE CHANNEL IMAGERY INDICATES SUBTLE SHORTWAVE
TROUGH...EMBEDDED IN ZONAL FLOW OVER WRN IA...THAT SHOULD CONTRIBUTE
TO ASCENT/LAPSE RATES ALOFT. MODIFIED FCST SOUNDINGS SUGGEST
LOW-LEVEL WAA AND MOIST ADVECTION...NEAR STRENGTHENING LLJ...SHOULD
MAINTAIN SUFFICIENT LOW-LEVEL THETAE TO SUPPORT 500-1000 J/KG MLCAPE
THROUGH ABOUT 03Z. 40-50 KT EFFECTIVE SHEAR MAGNITUDES WILL AID
FURTHER IN ORGANIZATION OF CONVECTION.

AFTER ABOUT 03Z...HAIL POTENTIAL WILL LEVEL OFF THEN SLOWLY
DIMINISH. DIABATIC SFC COOLING SHOULD STRENGTHEN MLCINH WITH
INFLOW-LAYER PARCELS BECOMING MORE ELEVATED. MEANWHILE MUCH OF
CONVECTION MAY OUTRUN RELATIVELY NARROW CORRIDOR WHERE PARCELS NOW
ARE SFC-BASED...AS LLJ VEERS.

..EDWARDS.. 10/25/2011

[Gilbertfly]

Non-severe. . .

but constant lightning and some very small hail. . .

not bad for the tail end of October. . .

[WeatherMonger]

Looks like the storm north of Peoria, IL near Rome could go severe

[WeatherMonger]

Sucks it's so late. Have a pretty calming rumble of thunder and light show off to the NNW. Would rather sit on the patio with a beer, but have to be up in 6 hours. It's windy out, but overall enjoyable evening.