Mar. 31 - Apr. 2 MW/GL/OV Severe Weather, SPC Risk Level: Day 1 Slight Risk Day 2 See Text Forecasts & OBS Options

[snowlover2]

There is a "See Text" for today across northern IL, a slight risk area has just been added to parts of IN/OH/KY for tomorrow, and a "See Text" for Monday for parts of WI/IL/MI/IN/OH.

Day 2

DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1238 PM CDT SAT MAR 31 2012

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH
VALLEY...

CORRECTED TO REMOVE THUNDER LINE IN FLORIDA

...OH VALLEY...
NORTHWEST FLOW WILL BE IN PLACE ACROSS THE NERN STATES SUNDAY WITH A
SHORTWAVE TROUGH MOVING SEWD ACROSS THE ERN GREAT LAKES DURING THE
DAY. AT THE SFC...A COLD FRONT SHOULD MOVE SWD INTO THE OH VALLEY
DURING THE AFTERNOON WITH AN AXIS OF MODERATE INSTABILITY DEVELOPING
FROM WRN KY NEWD ACROSS IND INTO WRN OH. SOME CONVECTION MAY BE
ONGOING ACROSS THE LOWER OH VALLEY SUNDAY MORNING WITH NEW
CONVECTION DEVELOPING ALONG AND AHEAD OF THE FRONT FROM CNTRL IND
SEWD ACROSS SRN OH. MODEL FORECASTS MOVE THIS CONVECTION SWD ACROSS
KY AND WV DURING THE LATE AFTERNOON AND EVENING.

A 75 TO 85 KT MID-LEVEL JET ASSOCIATED WITH THE SHORTWAVE TROUGH
OVER ERN GREAT LAKES WILL MOVE SEWD INTO THE CNTRL APPALACHIAN MTNS
SUNDAY WITH THE SERN EDGE OF THE JET AFFECTING THE OH VALLEY. THIS
WILL CREATE MODERATE TO STRONG DEEP LAYER SHEAR PROFILES ACROSS THE
SLIGHT RISK AREA. IN ADDITION...FORECAST SOUNDINGS BY MID-AFTERNOON
SHOW A MODERATELY UNSTABLE AIRMASS IN PLACE ACROSS SRN IND...SW OH
AND MOST OF KY WITH MUCAPE IN THE 1000 TO 1500 J/KG RANGE. THIS
COMBINED WITH STEEP MID-LEVEL LAPSE RATES MAY BE SUFFICIENT FOR
SUPERCELLS WITH LARGE HAIL IF CELLS CAN REMAIN DISCRETE. IF
SUPERCELLS CAN ORGANIZE...THEN AN ISOLATED TORNADO THREAT MAY EXIST
AS WELL. HOWEVER...THE DOMINANT CONVECTIVE MODE FOR SUNDAY REMAINS
UNCERTAIN AT THIS TIME AND FRONTAL FORCING COULD ENCOURAGE THE
DEVELOPMENT OF A LINE POSING A WIND DAMAGE THREAT.

This post has been edited by snowlover2: Apr 1 2012, 02:21 AM

[snowlover2]

IND AFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
345 PM EDT SAT MAR 31 2012

.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW.



.NEAR TERM /TONIGHT/...
AT THE BEGINNING OF THE TONIGHT PERIOD SKIES WILL BE MOSTLY CLEAR.
EXPECT TO SEE CLOUDS INCREASE ESPECIALLY IN THE NORTH OVERNIGHT. MAY
SEE AN MCS FORM TONIGHT IN IOWA THAT COULD MAKE IT/S WAY ACROSS
ILLINOIS AND INTO THE NORTHWESTERN COUNTIES. NOT CONFIDENT THIS WILL
REACH INDIANA BEFORE 12Z...BUT THOUGHT IT WILL BE CLOSE ENOUGH TO
INCLUDE A LOW CHANCE POP AFTER 9Z IN THE NORTHWEST. FOR TEMPERATURES
THOUGHT A CONSENSUS APPROACH WORKED WELL WITH HIGHER TEMPERATURES IN
THE WEST WITH WARM ADVECTION AND MORE CLOUDS THERE AND LESS IN THE
EAST.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
MODELS ARE IN DECENT AGREEMENT ON THE SHORT TERM SO WILL USE A
CONSENSUS GENERALLY...BUT THOUGHT EARLY ON THE NAM WAS A LITTLE
OVERZEALOUS IN POPS AND PRECIP ARRIVAL WITH THE SUNDAY SYSTEM SO
THERE WILL LEAN TOWARD THE GFS/ECMWF/SREFS. COULD HAVE AN MCS
ARRIVING IN THE NORTHWEST TO START OUT SUNDAY. VERY WEAK UPPER
FORCING WITH A LITTLE SHORTWAVE MOVING THROUGH BUT ISENTROPIC LIFT
SHOULD BE GOING THROUGH THE DAY ON SUNDAY. INSTABILITY WILL INCREASE
THROUGH THE DAY SO THAT MIXED LAYER CAPES OF 1000 TO 1500 OR SO WILL
BE IN PLACE ACROSS THE EAST BY THE AFTERNOON. MARGINAL SHEAR /BOTH
DIRECTIONAL AND SPEED/ WILL BE AVAILABLE AS WELL DURING THE
AFTERNOON...AND THUS THE INCLUSION OF A SLIGHT RISK FOR SEVERE
WEATHER ACROSS MUCH OF THE EASTERN COUNTIES FOR THAT TIME. ALSO HAVE
MID LEVEL LAPSE RATES AROUND 7-8C SO EXPECT THE MAIN THREAT TO BE
LARGE HAIL.

[snowlover2]

ILN AFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
521 PM EDT SAT MAR 31 2012



.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A COLD FRONT WILL MOVE SOUTH AND INFLUENCE THE FA SUNDAY INTO
SUNDAY EVENING. MODELS HAVE COME INTO MORE AGREEMENT FOR SUNDAY
WITH BRINGING SHOWERS AND THUNDERSTORMS INTO THE AREA AND
THEREFORE INCREASED PRECIPITATION CHANCES INTO THE LIKELY
CATEGORY. SOME OF THE STORMS MAY BE SEVERE DURING THE AFTERNOON
AND INTO THE EARLY EVENING HOURS WITH THE MAIN THREATS BEING WIND
AND HAIL. AN ISOLATED TORNADO WILL ALSO BE POSSIBLE HOWEVER. THE
COLD FRONT WILL PUSH SOUTH SUNDAY NIGHT AND PRECIPITATION WILL
COME TO AN END.

HIGH PRESSURE WILL BRIEFLY BUILD INTO THE FA FOR MONDAY HOWEVER
ANOTHER DISTURBANCE WILL BEGIN TO APPROACH THE AREA MONDAY NIGHT.
MODELS ARE NOT IN AGREEMENT ON THIS FEATURE WITH THE GFS BRINGING
WIDESPREAD PRECIPITATION INTO THE AREA MONDAY NIGHT HOWEVER THE
ECMWF KEEPS THE FA DRY. WENT CLOSER TO THE ECMWF SOLUTION AND
LIMITED PRECIPITATION CHANCES TO THE SLIGHT CHANCE AND CHANCE
CATEGORY.

[MichelleOH]

Looks like a long week....

[snowlover2]

SPC has just added a slight risk area for eastern IA and northern IL for hail in the newest day 1 outlook.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0754 PM CDT SAT MAR 31 2012

VALID 010100Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE DEEP SOUTH...

...THERE IS A SLGT RISK OF SVR TSTMS FOR ERN IA...NRN/CNTRL IL...



...ERN IA...NRN/CNTRL IL...
AFTERNOON MODEL GUIDANCE IS HIGHLY CONSISTENT IN MAINTAINING A
RELATIVELY NARROW 30-40 KT SWLY LLJ OVER SRN/ERN IA THIS
EVENING...THE NRN EXTENT ALREADY CONFIRMED BY THE DMX VAD WIND
PROFILE. CONTINUED ISENTROPIC ASCENT TO THE NE OF SURFACE WARM FRONT
ARCING ACROSS SERN IA INTO THE MID-MS VALLEY SHOULD FOSTER
SATURATION NEAR 850 MB AND REMOVAL OF MUCIN EVIDENT IN 00Z DVN RAOB.
700-500 MB LAPSE RATES AROUND 8 DEG C/KM WOULD SUPPORT MUCAPE
REACHING 1000-2000 J/KG AND LIKELY LEAD TO ELEVATED CONVECTION
DEVELOPING THROUGH TONIGHT. AMIDST A LONG/STRAIGHT
HODOGRAPH...POTENTIAL FOR SPLITTING ELEVATED SUPERCELLS PRODUCING
SEVERE HAIL APPEARS SUFFICIENT TO WARRANT AN UPGRADE TO SLIGHT RISK.

This post has been edited by snowlover2: Mar 31 2012, 08:13 PM

[WeatherMonger]

I'm not falling for it, but a bit of a surprise to see a slight risk go up across IA/IL for hail. I'm sure I'll sleep right though it

Beat by snowlover2

This post has been edited by WeatherMonger: Mar 31 2012, 08:13 PM

[WeatherMonger]

ILX did the infamous mid evening HWO update

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LINCOLN IL
820 PM CDT SAT MAR 31 2012

ILZ027>031-036>038-040>046-048-053>057-011100-
CHAMPAIGN-COLES-DE WITT-DOUGLAS-EDGAR-FULTON-KNOX-LOGAN-MACON-
MARSHALL-MASON-MCLEAN-MENARD-MOULTRIE-PEORIA-PIATT-SCHUYLER-STARK-
TAZEWELL-VERMILION-WOODFORD-
820 PM CDT SAT MAR 31 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS
AND EAST CENTRAL ILLINOIS.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL BE POSSIBLE LATE TONIGHT AS A WEATHER
DISTURBANCE DEVELOPS IN IOWA AND MOVES ACROSS NORTHERN ILLINOIS.
THE PRIMARY THREAT FROM THE THUNDERSTORMS OVERNIGHT WILL BE FROM
HAIL UP TO THE SIZE OF QUARTERS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS WILL BE POSSIBLE EARLY SUNDAY MORNING BEFORE THE
STORM SYSTEM MOVES OFF TO THE NORTHEAST. A FEW OF THE STORMS
EARLY IN THE MORNING MAY CONTINUE TO POSE A THREAT FOR HAIL.

ANOTHER ROUND OF THUNDERSTORMS WILL AFFECT THE AREA MONDAY
NIGHT AND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED DURING THE EARLY MORNING
HOURS...ROUGHLY FROM 200 AM UNTIL 800 AM.

$$


__________________________________________________
_________________________________




ILZ047-049>052-061>063-066>068-071>073-011100-
CASS-CHRISTIAN-CLARK-CLAY-CRAWFORD-CUMBERLAND-EFFINGHAM-JASPER-
LAWRENCE-MORGAN-RICHLAND-SANGAMON-SCOTT-SHELBY-
820 PM CDT SAT MAR 31 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS...EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS.

.DAY ONE...TONIGHT

THERE IS A CHANCE OF THUNDERSTORMS DEVELOPING LATE TONIGHT...BUT THE
MAJORITY OF THE STORMS SHOULD STAY JUST TO OUR NORTH OVERNIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

ANOTHER ROUND OF THUNDERSTORMS WILL AFFECT THE AREA MONDAY
NIGHT AND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

$$

SMITH

[WeatherMonger]

MESOSCALE DISCUSSION 0402
NWS STORM PREDICTION CENTER NORMAN OK
0852 PM CDT SAT MAR 31 2012

AREAS AFFECTED...CNTRL/ERN IA...NWRN IL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 010152Z - 010245Z

AN INCREASE IN TSTM COVERAGE IS ANTICIPATED THROUGH THE LATE EVENING
HRS FROM CNTRL IA EWD INTO NWRN IL...WITH A PRIMARY THREAT FOR LARGE
HAIL. CONSIDERABLE UNCERTAINTY SURROUNDING SPECIFIC TIMING/MAGNITUDE
OF SVR POTENTIAL EXISTS...BUT CONVECTIVE TRENDS ARE BEING MONITORED
FOR A POSSIBLE WW...PERHAPS AS SOON AS THE NEXT 1-2 HRS.

SFC ANALYSIS FROM 01Z PLACES A WARM FRONT FROM 30 SSE OTM TO 10 NNW
SUX. TO THE NE OF THE WARM FRONT...RADAR ECHOES HAVE DEVELOPED
APPROXIMATELY 40 W OF CEDAR RAPIDS...WITH A NARROW WAA REGIME AIDED
BY A 30-40 KT SWLY LLJ /PER DMX VWP/. WITH TIME...A GRADUAL
INTENSIFICATION/EWD EXPANSION OF TSTMS IS EXPECTED. STEEP MIDLEVEL
LAPSE RATES /SAMPLED AT 7-8 C/KM PER DVN 00Z SOUNDING/ AND MUCAPE
VALUES EXCEEDING 1000 J/KG...ALONG WITH MODERATE W-NWLY MIDLEVEL
FLOW...WILL SUPPORT ELEVATED TSTMS /SOME SUPERCELLS/ CAPABLE OF
PRODUCING LARGE HAIL AS THE PRIMARY THREAT. A MAJORITY OF AVAILABLE
HIGH-RESOLUTION CONVECTION ALLOWING GUIDANCE /INCLUDING 23Z WRF-HRRR
AND 12Z WRF-NMM/ APPEARS TO BE TOO SLOW/FAR EAST WITH INITIAL
CONVECTIVE DEVELOPMENT...BUT GENERAL TREND IS FOR A GRADUAL EWD
EXPANSION OF TSTMS INTO ERN IA AND EVENTUALLY NRN IL AS LOW-LEVEL
WAA BECOMES FOCUSED FARTHER E. CONSIDERABLE UNCERTAINTY SURROUNDING
EVOLUTION OF CONVECTION AND TIMING OF ASSOCIATED LARGE HAIL THREAT
REMAINS...BUT THE AREA IS BEING MONITORED FOR A POSSIBLE WW.

..ROGERS.. 04/01/2012


ATTN...WFO...LOT...ILX...DVN...ARX...DMX...

[jdrenken]

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 124
NWS STORM PREDICTION CENTER NORMAN OK
925 PM CDT SAT MAR 31 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EAST CENTRAL IOWA
NORTHWEST ILLINOIS

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 925 PM
UNTIL 400 AM CDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES SOUTHWEST OF
CEDAR RAPIDS IOWA TO 5 MILES EAST NORTHEAST OF MARSEILLES
ILLINOIS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 123...

DISCUSSION...AREA OF TSTMS RELATED TO LOW-LEVEL WAA WILL SPREAD
EWD/ESEWD FROM ERN IA INTO NW IL OVERNIGHT. A FEED OF MUCAPE
APPROACHING 1000 J/KG AND SUBSTANTIAL CLOUD-LAYER VERTICAL SHEAR
WILL SUPPORT ORGANIZED STORMS AND POTENTIALLY AN ELEVATED SUPERCELL
OR TWO...WITH AN ATTENDANT RISK FOR AT LEAST ISOLATED LARGE HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 29030.


...THOMPSON

[snowlover2]

New day 1 shifted the slight risk area westward from the previous day 2. Large hail appears to be the main threat.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT SUN APR 01 2012

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE OH VALLEY
TODAY THROUGH THIS EVENING...

...SYNOPSIS...
AN AMPLIFIED UPPER-LEVEL TROUGH WILL SHIFT EWD ACROSS THE WRN CONUS
AND REACH THE ROCKIES BY EARLY MON. A STOUT UPPER-LEVEL RIDGE WILL
EMANATE NWD FROM AN ANTICYCLONE SHIFTING EWD ACROSS THE SRN HIGH
PLAINS TO THE OZARK PLATEAU. A SHORT WAVE TROUGH OVER ONTARIO WILL
AMPLIFY ACROSS THE NORTHEAST. THIS SHOULD INDUCE WEAK CYCLOGENESIS
OVER THE MID-ATLANTIC WITH A W/E-ORIENTED COLD FRONT SINKING SWD
ACROSS THE UPPER OH VALLEY AND MIDWEST THIS EVENING.

...OH VALLEY...
A CLUSTER OF ELEVATED TSTMS WITH A RISK OF ISOLATED SEVERE HAIL
SHOULD BE ONGOING AT 12Z THIS MORNING IN PORTIONS OF IND/ERN IL AS
ISENTROPIC LIFT PERSISTS NE OF AN ADVANCING WARM FRONT ACROSS THE
MID-MS TO TN VALLEYS. GUIDANCE DOES DIFFER TO SOME EXTENT WITH THE
HANDLING OF THIS CONVECTION LATER THIS MORNING...BUT CONSENSUS
SUGGESTS IT SHOULD CONTINUE TO TRACK E/SEWD TOWARDS PARTS OF THE OH
VALLEY. WHEN/WHERE THIS ACTIVITY BECOMES SURFACE-BASED AS DIURNAL
HEATING ENSUES IS UNCERTAIN. THE NAM AND ETA-KF CONTROL MEMBER OF
THE SREF APPEAR TOO AGGRESSIVE WITH LOW-LEVEL MOISTURE RETURN INTO
THE CNTRL OH VALLEY DEPICTING MEAN MIXING RATIOS OF 12-13 G/KG BY
LATE AFTERNOON /INDICATIVE OF THE AIR MASS OVER TEXARKANA ON SAT
EVENING/. WITH UPPER 50S TO LOWER 60S SURFACE DEW POINTS APPEARING
MORE PROBABLE...AT LEAST ISOLATED SURFACE-BASED TSTMS SHOULD FORM
DURING THE AFTERNOON...EITHER IN PRE-FRONTAL CONFLUENCE BANDS ALONG
THE S/WRN FLANK OF THE REMNANT OVERNIGHT MCS OR ALONG THE BACKDOOR
COLD FRONT SAGGING SWD INTO THE MIDWEST.

DESPITE WLY LOW-LEVEL FLOW...THE KINEMATIC PROFILE WILL STRENGTHEN
DURING THE AFTERNOON AS THE SHORT WAVE TROUGH AMPLIFIES OVER THE
NORTHEAST. HOWEVER...GUIDANCE DIFFERS ON THE DEGREE OF STRENGTHENING
OVERLAPPING LARGER INSTABILITY...WITH THE NAM MORE AGGRESSIVE
COMPARED TO THE GFS AND 12Z ECMWF. THIS BREEDS FURTHER
UNCERTAINTY...BUT HODOGRAPHS SHOULD STILL BE SUFFICIENTLY ELONGATED
FOR SUPERCELL STRUCTURES PRODUCING MAINLY LARGE HAIL /POSSIBLY
SIGNIFICANT/ AND DAMAGING WIND. WILL DEFER ON INTRODUCING HIGHER
PROBABILITIES GIVEN THE RELATIVELY LOW CONFIDENCE IN HOW BOTH
ONGOING CONVECTION AND THE ENVIRONMENT WILL EVOLVE TODAY.

[The Snowman]

Got in on a few rumbles of thunder at 5:30 this morning.

[jdrenken]

Watching the cloud cover in NE IL where a warm front and stalled boundary is meeting.

[WeatherMonger]

Wasn't mentioned, and new update will be out shortly so I'll just post the one image. They did include a 30% hail threat overlapping hatched areas in the 1630Z update for those of you in SW OH, SE IN and N KY



This post has been edited by WeatherMonger: Apr 1 2012, 02:29 PM

[The Snowman]

Well, luckily I'm not in line for any storms this afternoon, because MKX, LOT, and DVN are all offline right now...

[WeatherMonger]

Small 5% tornado risk added



Hail



Wind had 30% added

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT SUN APR 01 2012

VALID 012000Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY
AND CNTRL APPALACHIAN MTNS...

THE MAIN CHANGE TO THE OUTLOOK IS TO NARROW THE HIGHER END
PROBABILITIES TO A CORRIDOR FROM SE IND SEWD ACROSS NRN KY. MODERATE
INSTABILITY SHOULD DEVELOP ACROSS THE AREA AS MOISTURE CONTINUES TO
ADVECT EWD THIS AFTERNOON. SHORT-TERM MODEL FORECASTS ARE IN GENERAL
AGREEMENT THAT THE GREATEST CONVECTIVE THREAT EARLY THIS EVENING
WILL EXIST SEWD ACROSS THE CINCINNATI AREA WHERE THE COMBINATION OF
DEEP LAYER SHEAR AND INSTABILITY MAY SUPPORT A THREAT FOR SUPERCELLS
WITH VERY LARGE HAIL. OTHERWISE...THE OUTLOOK LOOKS TO BE ON TRACK.

..BROYLES.. 04/01/2012

.PREV DISCUSSION... /ISSUED 1118 AM CDT SUN APR 01 2012/

...SYNOPSIS...

LARGE-SCALE PATTERN WILL UNDERGO FURTHER AMPLIFICATION DURING THE D1
PERIOD AS WRN U.S. TROUGH PROGRESSES INTO THE ROCKIES...AND A
DOWNSTREAM RIDGE BUILDS FROM THE CANADIAN PRAIRIE PROVINCES THROUGH
THE MS RIVER VALLEY. E OF THE RIDGE...AN 80-90 KT MIDLEVEL JET
STREAK OVER SRN ONTARIO WILL DIG SEWD TOWARD THE MID-ATLANTIC
COAST...SUPPORTING INTENSIFICATION OF A TROUGH FROM THE CANADIAN
MARITIMES INTO NWRN ATLANTIC.

IN THE LOW LEVELS...A COLD FRONT ADVANCING SWD FROM THE GREAT LAKES
WILL MERGE WITH A WARM FRONT LIFTING NWD/NEWD THROUGH THE OH
VALLEY...ENHANCING BAROCLINITY OVER THESE AREAS. ELSEWHERE...A COLD
FRONT WILL MOVE FROM THE NRN ROCKIES EWD/SEWD THROUGH NRN
PLAINS...WHERE IT WILL INTERSECT A DRYLINE OR PRE-FRONTAL TROUGH
EXTENDING FROM CNTRL PARTS OF NEB/KS INTO SWRN TX.

...OH VALLEY INTO CNTRL APPALACHIANS THIS AFTERNOON/TONIGHT...

MASS RESPONSE TO ABOVE-MENTIONED JET STREAK --MANIFEST AS A WLY 30
KT LLJ-- WILL ENHANCE THE EWD FLUX OF A WARM AND MOIST BOUNDARY
LAYER CURRENTLY OBSERVED NEAR THE CONFLUENCE OF THE MS AND OH RIVERS
EWD ACROSS REGION TODAY. THIS PROCESS WILL OCCUR BENEATH THE ERN
EXTENSION OF AN EML /CHARACTERIZED BY MIDLEVEL LAPSE RATES OF
7.0-7.5 C PER KM/...YIELDING AFTERNOON MLCAPE VALUES OF 1000-2500
J/KG ACROSS EWD-DEVELOPING WARM SECTOR.

REGENERATIVE TSTM DEVELOPMENT IS ANTICIPATED THIS AFTERNOON OVER
PARTS OF IND/OH OWING TO PERSISTENT LOW-LEVEL WAA AND GLANCING
INFLUENCE OF IMPULSE DIGGING SEWD THROUGH THE LOWER GREAT LAKES.
STORMS MAY SUBSEQUENTLY BUILD WWD INTO A PROGRESSIVELY MORE
UNSTABLE...BUT STRONGER CAPPED ENVIRONMENT. FORECAST HODOGRAPHS
EXHIBIT PRONOUNCED VEERING OF WINDS WITH HEIGHT WITH 40-50 KT OF
EFFECTIVE BULK SHEAR. AS SUCH...THE POTENTIAL FOR SUPERCELLS WILL
EXIST WITH AN ATTENDANT RISK FOR VERY LARGE HAIL...DAMAGING WINDS
AND PERHAPS A COUPLE OF TORNADOES.

STORMS WILL LIKELY CONGEAL INTO A FORWARD-PROPAGATING MCS LATER THIS
EVENING INTO TONIGHT WITH A THREAT FOR DAMAGING WINDS AND LARGE HAIL
CONTINUING ACROSS PARTS OF THE CNTRL APPALACHIANS.

[jdrenken]

Small 5% tornado risk added

It was there earlier. They shaved it a good deal.

[jdrenken]

MESOSCALE DISCUSSION 0407
NWS STORM PREDICTION CENTER NORMAN OK
0342 PM CDT SUN APR 01 2012

AREAS AFFECTED...ECNTRL IL...CNTRL IND...WCNTRL OH

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 012042Z - 012215Z

LATEST VIS IMAGERY SUGGESTS DEEPER CONVECTIVE UPDRAFTS ARE
DEVELOPING ACROSS ECNTRL IL INVOF IROQUOIS/VERMILION COUNTIES. THIS
IS LIKELY INDICATIVE OF STRONG THERMAL HEATING AT LOW LEVELS AND
STEEP LAPSE RATES. HOWEVER...FRONTAL CONVERGENCE SHOULD GRADUAL SAG
SWD INTO THIS ZONE OF STEEPER LOW LEVEL LAPSE RATES WHICH SHOULD
ENCOURAGE THUNDERSTORM DEVELOPMENT OVER THE NEXT FEW HOURS. THIS
SCENARIO IS BECOMING INCREASINGLY LIKELY...THOUGH DEEP WLY FLOW MAY
DELAY THE ONSET OF THUNDERSTORMS UNTIL 22-23Z TIME FRAME. DEEP
LAYER SHEAR IS CERTAINLY SUPPORTIVE OF ORGANIZED UPDRAFTS THAT WOULD
MOVE SEWD AT ROUGHLY 25-30KT. LATEST THINKING IS AN E-W CORRIDOR OF
CONVECTION COULD EVOLVE ALONG THE FRONT INTO THE EARLY EVENING HOURS
WHICH WOULD POSE AT LEAST A THREAT FOR LARGE HAIL AND DAMAGING
WINDS. WILL CONTINUE TO MONITOR FOR POSSIBLE SEVERE THUNDERSTORM
WATCH.

..DARROW.. 04/01/2012

[Juniorrr]

Hmm... maybe some scattered thunderstorms around here.

[SWOhioweather]

Well, looks like things never really got going today.

[jdrenken]

Well, looks like things never really got going today.

In a word...cap.