April 7th-10th Severe Weather

[SEMIweather]

yeah the RUC/HRRR have been indicating storm initiation late this afternoon over OK. Last I checked LI's were -9 and SBCAPE was 3000.

Ya I'm about to go chasing with a couple of people I know who have a car and are being nice and letting me come along, lol. Here's our target area...

[JoMo]

Doesn't look like too bad of a spot.

[Chicago Storm]

FWIW...

The 12z NMM has development between 0-3z tomorrow evening in NE. Kansas and trailing back into C. Kansas. Some of this activity eventually pushes into N. Missouri, Iowa and later N. Illinois.

On the other hand, the ARW does not have any development.

[Iastfan112]

I am really liking the chances for good storms in my area Saturday.

[prinsburg_wx]

I just noticed the RGEM has been fixed on Ewall. I do find the RGEM a somewhat useful piece of guidance in convective scenarios under certain circumstances.

I'm still learning what the hell all these severe indexes mean but i made the NAM & RGEM EHI..the 12z RGEM has my interest up here at hr 36.

RGEM & NAM

[baroclinic_instability]

I'm still learning what the hell all these severe indexes mean but i made the NAM & RGEM EHI..the 12z RGEM has my interest up here at hr 36.

RGEM & NAM

You should get your website up and running soon. You have good plots.

[radarman]

SPC issued a new meso discussion for central Oklahoma tonight and say a watch is possible....

Highly conditional threat but they could really use some precip, especially south of OKC.

edit-- they have also extended the slight risk into SW Oklahoma now

[A-L-E-K]

anyone with notes from the LOT briefing?

[wisconsinwx]

Getting more excited after reading MKX's discussion. Saying many of the models, including the Euro, have severe storms already firing Sunday afternoon in Southern Wisconsin. I thought we might have to wait until after dark, but that may not be the case.

[Jebman]

Impressive warmth for April in the Mid Atl coming up Sunday and Monday - Highs in the lower 90s probably with at least upper 50s dews. Might have some decent thunderstorm potn

[Stebo]

Not much in IA tomorrow per the SREF but this pops at 9z tomorrow night/Sunday Morning.

[Chicago Storm]

Not much in IA tomorrow per the SREF but this pops at 9z tomorrow night/Sunday Morning.

That area highest of probs has been shifting a tad north with each run. Several runs ago it was maxed out at 40 in C. Iowa.

[wisconsinwx]

Take it fwiw but Forbes' Tor-Con has SE and EC Wisconsin at a 5 for Sunday afternoon and evening. Pretty decent for an event this early in a severe season.

[Stebo]

GRR Talking up the potential some.

OF COURSE THE BIG ISSUE FOR THE SHORT TERM IS THE THREAT FOR

STRONG THUNDERSTORMS LATE SATURDAY NIGHT INTO SUNDAY MORNING AS THE

WARMEST AIR OF THE SEASON HEADS THIS WAY WITH A 40 TO 60 KNOT LOW

LEVEL JET. HOWEVER THERE ARE SOME ISSUES WITH THESE STORMS. FIRST UP

IS THE LOW LEVEL JET IS SATURDAY NIGHT IS AIDED AT MN/WI NOT

MICHIGAN. THE OTHER ISSUE IS THE AIR MASS WILL BE STRONGLY CAPED

UNTIL THE MID LEVEL SHORTWAVE BREAKS THE CAP TOWARD EVENING. ON THE

UP SIDE FOR THE STORMS... THERE IS DEEP...FAT CAPE OVER THE UPPER

MIDWEST SATURDAY NIGHT ENOUGH SO THAT SPC IS SUGGESTING VERY LARGE

HAIL FROM THE STORMS. IN ANY EVENT THE STORMS WILL BE AIDED BY

PRECIPTABLE WATER AMOUNTS OF 300 TO 400 PCT OF NORMAL. ONCE THE

STORMS FORM THEY WILL HEAD NORTHEAST AT FIRST THEN TURN MORE EAST TO

EAST SOUTHEAST FOLLOWING THE 1000/700 MB THICKNESS PATTERN INTO

CENTRAL LOWER MICHIGAN. THIS SHOULD BE WELL AFTER MIDNIGHT...MORE

LIKELY TOWARD SUNRISE BEFORE THE REACH SOUTHWEST LOWER MICHIGANS

WESTERN LAKE SHORE AREAS. BY THEN ANY SURFACE BASE CAPE WILL BE

GONE. GIVEN THE DIFFLUENT THICKNESS PATTERN AND HIGH PRECIPITABLE

WATER VALUES IN PLACE... THE THREAT FOR HEAVY RAINFALL IS

SIGNIFICANT NORTH OF INTERSTATE 96.

THERE IS A TORNADO ISSUE SUNDAY MORNING...ONCE THE SUN COMES UP AND

STARTS HEATING THE AIR ONCE AGAIN... THERE WILL BE THE POTENTIAL FOR

ISOLATED TORNADOES NEAR THE WARM FRONT (WHERE MOST OF SOUTHWEST

MICHIGAN TORNADOES HAPPEN). THIS FEATURE IS SHOWN NICELY BY THE SPC

09Z ENSEMBLE FORECAST FOR SIGNIFICANT TORNADOES (SCARY). GIVEN THE

HIGH SHEAR VALUES AND SIGNIFICANT CAPE IN PLACE NEAR THE WARM

FRONT...THIS WILL BE A REAL THREAT

OK ONCE THE WARM FRONT PUSHES ALL THAT OFF TO THE NORTHEAST BY EARLY

AFTERNOON THE 1000/925 THICKNESS TOOL... THE 1000/850 THICKNESS TOOL

AND THE 1000 MB FORECAST TEMPERATURE ARE NOW FORECAST EVEN HIGHER BY

THE NAM12 12Z RUN THAN WERE FORECAST YESTERDAY AND THOSE VALUES

EXCEEDED THE VALUES THAT OCCURRED AND WERE UNDER FORECAST BY THE

MODELS FOR LOWER 80S EVENT EARLY IN APRIL LAST YEAR AND THE YEAR

BEFORE THAT. IN THE 2008 EVENT THERE WAS RAIN AND ONLY 59 PCT

SUNSHINE YET GRR GOT TO 82F! SO GIVEN THAT THE 1000/925 THICKNESS

TOOL SO FAR THIS SPRING HAS BEEN UNDER FORECASTING HIGHS WHEN THE

SUN COMES OUT (IT SHOULD BE OUT FROM LATE MORNING ON SUNDAY OVER

AREA SOUTH OF INTERSTATE 96) I HAVE TO BELIEVE REALISTIC VALUES FOR

HIGH TEMPS WILL BE IN THE LOWER TO MID 80S FOR GRR...AZO...BTL AND

JXN. THE SOUTH WIND (NOT OFF LAKE MICHIGAN WILL HUGELY HELP THAT

CAUSE TOO).

MAIN FOCUS REMAINS ON CONVECTION FOR SUNDAY NIGHT AND MONDAY

MORNING. THE TIMING OF THE COLD FRONT/SQUALL LINE OF THUNDERSTORMS

IS HANDLED A BIT DIFFERENTLY BETWEEN THE GFS...NAM...AND ECMWF.

WHILE THE ECMWF HAS BEEN INDICATING A SLOWER SOLUTION FOR DAYS

NOW...IT ACTUALLY PUSHES THE FRONT THROUGH THE QUICKEST OF THE THREE

MODELS. A COMPROMISE SOLUTION HAS THE THUNDERSTORMS APPROACHING THE

LAKESHORE AREA LIKELY BETWEEN 2AM AND 5AM MONDAY MORNING. THIS IS

NOT A CLIMATOLOGICAL FAVORABLE TIME FOR SEVERE WEATHER...BUT THE

MODELS ARE STRONGLY SUGGESTING THE LINE WON`T CONSIDERABLY FILL IN

UNTIL THE 00Z-06Z MONDAY WINDOW ANYWAY...NEAR AND SOUTH OF THE

CHICAGO METRO AREA. THIS LINE WILL BE MOVING NORTHEAST.

FAVORABLE LLJ DYNAMICS ARE IN PLACE AROUND 06Z MONDAY...WITH THE GFS

INDICATING A STRONGER LLJ BY ABOUT 10KTS OVER THE ECMWF. THIS SHOULD

HELP CONTINUE FUELING THE THUNDERSTORMS. LOW LEVEL MOISTURE FLUX

CONVERGENCE IS SEEN SHARPLY WITH THE FRONT OFF THE GFS 06Z MONDAY

FORECAST...AND TO A LESSER DEGREE (AND EARLIER) WITH THE ECMWF. THE

NAM IS SLOWER THAN BOTH OF THEM. THE ECMWF SOLUTION WOULD GIVE US A

BETTER SHOT AT SEVERE THUNDERSTORMS GIVEN THE QUICKER TIMING. EVEN

WITH THIS KIND OF SOLUTION HOWEVER...LAKE MICHIGAN MAY PLAY AN

IMPORTANT ROLE IF THESE STORMS INGEST MARINE LAYER STABILITY...WHICH

IS CLEARLY IN PLACE WITH THE COLD APRIL WATER TEMPERATURES.

AN ANALYSIS OF MODEL SOUNDINGS LEAVES SOME ROOM FOR BOTH LARGE HAIL

AND DAMAGING WIND GUSTS. WHILE THERE IS SOME BUOYANCY RESIDING IN

THE -10C TO -20C RANGE FOR HAIL GROWTH...IT LOOKS TO BE SHORT-LIVED

AS THE SOUNDINGS SUGGEST A TRANSITION TO MORE OF A TALL SKINNY CAPE.

NOT SURE THERE IS GOING TO BE SUFFICIENT CAPE IN THE HAIL GROWTH

REGION TO PRODUCE SEVERE HAIL. THESE STORMS SHOULD CERTAINLY BE

HEAVY RAIN PRODUCERS HOWEVER. THE DOWNSIDE TO THIS THREAT IS THE

LINE WILL BE MOVING FAIRLY QUICKLY ACROSS THE AREA. DAMAGING WIND

GUSTS ARE NOT OUT OF THE QUESTION AS THERE SHOULD STILL BE A MIXED

LAYER CAPABLE OF BRINGING DOWN SEVERE CRITERIA WINDS...ALTHOUGH WE

WILL CERTAINLY NOT SEE THE TYPE INSTABILITY EXPECTED DURING THE

DAYTIME HOURS SUNDAY.

DTX talking down the potential.

EXPECT EVEN WARMER TEMPERATURES BY SUNDAY WITH WIDESPREAD READINGS IN

THE MID/UPPER 70S AS A WARM FRONT LIFTS NORTH OF THE REGION. AS

THE WARM FRONT LIFTS THROUGH THE REGION LATE SATURDAY NIGHT INTO

SUNDAY MORNING...EXPECT AN AREA OF ELEVATED CONVECTION TO SKIRT

PARTS OF THE AREA. MODELS STILL SUGGEST THAT THE NORTHERN PORTIONS

OF THE CWA WILL HAVE THE BEST POTENTIAL FOR RAINFALL. WILL ADJUST

FORECAST ONLY SLIGHTLY TO BRING THE 60+% CHANCE OF SHOWERS/STORMS

SLIGHTLY SOUTH...BUT STILL NORTH OF THE I 69 CORRIDOR. CHANCES

THEN DECREASE QUICKLY HEADING SOUTH INTO THE WARM SECTOR...WITH

JUST A 20-30 PERCENT CHANCE NEAR THE OHIO BORDER. ANY SUNDAY

MORNING ACTIVITY SHOULD LIFT NORTHEAST WITH THE FRONTAL BOUNDARY

BY EARLY AFTERNOON.

A RENEWED CHANCE OF SHOWERS/THUNDERSTORMS STILL COMES INTO PLAY LATE

SUNDAY NIGHT INTO THE FIRST HALF OF THE DAY MONDAY AS AFOREMENTIONED

UPPER TROUGH LIFTS THROUGH THE UPPER MIDWEST ON ITS WAY TO THE

NORTHERN GREAT LAKES AND DRAGS A COLD FRONT THROUGH THE AREA. TIMING

OF THIS FRONT REMAINS SOMEWHAT IN QUESTION...BUT WILL MOST LIKELY

FALL BETWEEN 12Z-18Z ON MONDAY WITH A GOOD LIKELIHOOD OF CONVECTION

IN ADVANCE AND ALONG THIS FEATURE. CURRENT FORECAST SEEMS TO REMAIN

IN DECENT SHAPE. THERE WILL BE A CHANCE OF SEVERE WEATHER WITH THIS

ACTIVITY GIVEN THE STRENGTH OF THE PASSING UPPER TROUGH AND AT LEAST

DECENT INSTABILITY WITHIN THE WARM SECTOR. THE MAIN LIMITING FACTOR

WILL BE THE TIMING...CURRENTLY NEAR THE DIURNAL INSTABILITY MINIMUM.

[Stebo]

That area highest of probs has been shifting a tad north with each run. Several runs ago it was maxed out at 40 in C. Iowa.

Yeah, further north and a touch later each run. Certainly something to monitor that is for sure.

[Chicago Storm]

DVN...

...POTENTIAL SIGNIFICANT SEVERE WEATHER EVENT LATE SUNDAY REMAINS THE

PRIMARY FORECAST CONCERN...

SAT NGT...

SFC WARM FRONT TO CONTINUE LIFTING NORTH THROUGH THE REGION. MOST

LIKELY AREA FOR STORM DEVELOPMENT BY EARLY EVE WILL BE OVER EXTREME

EASTERN NE AND WESTERN IA... WHERE SOME SFC BASED STORMS WITH

ATTENDANT DAMAGING WIND/TORNADO THREAT POSSIBLE... ALONG WITH LARGE

HAIL. STORMS SHOULD THEY DEVELOP WILL LIKELY CONTINUE TO MAINTAIN

THEMSELVES AND INCREASE IN COVERAGE SAT EVE AS THEY TAP STRENGTHENING

LOW LEVEL JET OF 55-65 KTS. STORM MOTION WOULD BE TO THE N/NE. SOME

OF THIS ACTIVITY COULD BRUSH OR DEVELOP INTO SOME OF OUR NORTHERN

AND WESTERN COUNTIES... ROUGHLY ALONG AND N/W OF CEDAR RAPIDS IA TO

FREEPORT IL AXIS. TIMING WOULD BE MOST LIKELY AFTER 7-8PM THROUGH

ABOUT 1 AM WITH ANY SEVERE THREAT BEING LARGE HAIL GIVEN DRY AIR ALOFT

AND STEEP MID LEVEL LAPSE RATES. MUCH OF SEVERE THREAT ALONG WITH

STORM COVERAGE EXPECTED WEST AND NORTH OF OUR COUNTY WARNING AREA WITH

MAIN BRANCH OF LOW LEVEL JET. MINS TO BE QUITE MILD WITH SOUTH WINDS

10-20 MPH KEEPING TEMPS IN THE 60S... WHICH WOULD BE RECORD WARM MINS

IN SOME LOCATIONS.

SUN-SUN NGT...

INGREDIENTS IN PLACE FOR WIDESPREAD SEVERE WEATHER OUTBREAK FROM THE

UPPER MIDWEST TO THE LOWER MISSISSIPPI VALLEY... AS POTENT SHORTWAVE

TROUGH EJECTS FROM ROCKIES INTO THE UPPER MIDWEST. NEARLY ALL MODEL

SOLUTIONS SHOW UPPER LEVEL LOW CLOSING OFF OVER THE UPPER MIDWEST 12Z

MON THOUGH SOME DISAGREEMENT ON LOCATION. THIS STRONG FORCING ALONG WITH

POTENT LOW LEVEL JET OF 55-65 KTS FEEDING VERY WARM/MOIST UNSTABLE

AIR INTO REGION AND ADDITIONAL LIFT FROM EXIT REGION OF STRONG 100-125 KT

CYCLONICALLY CURVED JET... TO FUEL WIDESPREAD SEVERE WEATHER FOCUSING

ALONG WARM FRONT TO OUR NORTH AND THEN COLD FRONT/DRYLINE TO OUR WEST

AND SOUTHWEST. PRESENCE OF EML LOOKS TO SUFFICIENTLY CAP WARM SECTOR

FOR MUCH OF DAY SUNDAY UNTIL AROUND OR AFT 20-21Z (34 PM CDT)... BEFORE

THE LARGE SCALE ASCENT WEAKENS CAP AND VIGOROUS CONVECTIVE DEVELOPMENT

ENSUES. INITIATION LIKELY IN OUR CWA AND/OR JUST WEST WITH STRONG

SHEAR PROFILES SUPPORTIVE OF SUPERCELLS WITH VERY LARGE HAIL AND TORNADOES.

ACTIVITY THEN LIKELY TO COALESCE INTO A SQUALL LINE AND RACE EWD WITH

PRIMARILY DAMAGING WIND THREAT TO 70 MPH AND LARGE HAIL... THOUGH ISOLATED

TORNADOES POSSIBLE. SPC DAY3 MODERATE RISK LOOKS QUITE REASONABLE WITH

EVENT LOOKING FAIRLY SIMILAR TO LAST SUNDAYS WITH EXCEPTION OF MUCH

BETTER LOW LEVEL MOISTURE WITH THIS SYSTEM (WIDESPREAD SFC DEWPTS IN THE

L/M 60S) PROMOTING INCREASED RISK OF DAMAGING WINDS AND TORNADOES.

FOLKS WILL DEFINITELY WANT TO STAY TUNED TO LATEST WEATHER INFORMATION

AND ANY WATCHES/WARNINGS THIS WEEKEND. STORM MOTIONS WILL BE VERY FAST

(40-50+ MPH) LIMITING REACTION TIMES. THIS ACTIVITY LIKELY TO BE EAST OF

THE CWA MIDNIGHT SUNDAY NIGHT. ADDITIONAL SCATTERED SHRA/TSRA POSSIBLE

OVERNIGHT WITH CONTINUED SWLY 850 MB FLOW.

[Thundersnow12]

LOT

MODELS IN REASONABLY GOOD AGREEMENT WITH DEEP LOW ON THE ORDER OF

985-990 MB PULLING INTO SOUTHEAST MINNESOTA. MEANWHILE WARM FRONT

SURGES WAY NORTH OF THE AREA. MUCH OF THE DAY COULD FEATURE

CAPPING WITH STRONG ELEVATED MIXED LAYER SPREADING ACROSS THE OHIO

VALLEY AND LOWER LAKES REGION. TEMPERATURES WILL CLIMB INTO THE

80S...WITH POSSIBLE EXCEPTION OF THE IMMEDIATE LAKE SHORE. EVEN

THERE MOST AREAS WILL HIT AT LEAST UPPER 70S BEFORE ANY LAKE

BREEZE KICKS IN. BUT THIS WILL NOT PENETRATE VERY FAR INLAND IF AT

ALL. COUPLED WITH MID 60S DEWPOINTS...IT WILL GET VERY UNSTABLE.

UNCERTAINTY IS IN WHETHER ANY CONVECTION FORMS BEFORE NIGHTFALL.

THE 12Z ECMWF IS MOST AGRESSIVE IN BREAKING THE CAP RIGHT BEFORE

00Z OVER NORTHWEST HALF OF AREA.

AT NIGHT MODELS ALL BRING VIGOROUS SQUALL LINE ACROSS ILLINOIS AS

STRONG DYNAMIC FORCING WEAKENS THE CAP. A DRYLINE FEATURE APPEARS

TO PRECEDE THE COLD FRONT BY ROUGHLY 6 HOURS...WITH ENHANCED LOW

LEVEL CONVERGENCE.

PARAMETER SPACE COMPARED WITH APRIL TORNADO OUTBREAKS IN THE

NORTHERN ILLINOIS AREA IS VERY FAVORABLE ON ALL MODELS. STRONG

DEEP LAYER SHEAR IN THE RANGE OF 60-80 KNOTS IN 0-6KM LAYER ALONG

WITH 50-60 KNOT 850 MB JET LOOKS POTENT FOR SUPERCELLS.

PROBLEM...AS ALWAYS...IS THE NATURE OF THE INITIATION OF THE

STORMS AND HOW THE STORM MODE EVOLVES. DETAILS OF THIS INCLUDE

STORM RELATIVE FLOW...SHEAR ORIENTATION RELATIVE TO THE LOW LEVEL

BOUNDARY...AND EFFECTS OF OUTFLOW FROM THE PREVIOUS NIGHTS

CONVECTION. SO WHETHER OR NOT THIS IS A MEMORABLE TORNADIC

OUTBREAK OR NOT IS STILL IN QUESTION.

[outflow]

GRR Talking up the potential some.

DTX talking down the potential.

grr must have decided to re-word the tornado paragraph, look now:

THERE IS A TORNADO ISSUE SUNDAY MORNING...ONCE THE SUN COMES UP AND

STARTS HEATING THE AIR ONCE AGAIN... THERE WILL BE THE POTENTIAL FOR

ISOLATED TORNADOES NEAR THE WARM FRONT (WHERE MOST OF SOUTHWEST

MICHIGAN TORNADOES HAPPEN). THIS FEATURE IS SHOWN NICELY BY THE SPC

09Z ENSEMBLE FORECAST FOR SIGNIFICANT TORNADOES (SCARY). GIVEN THE

HIGH SHEAR VALUES AND SIGNIFICANT CAPE IN PLACE NEAR THE WARM

FRONT...THIS WILL BE A REAL THREAT

[Thundersnow12]

Take it fwiw but Forbes' Tor-Con has SE and EC Wisconsin at a 5 for Sunday afternoon and evening. Pretty decent for an event this early in a severe season.

tor-con, bore-con

[Thundersnow12]

DSM

CONTINUED FOCUS IS ON THE POTENTIAL FOR A SIGNIFICANT SEVERE

WEATHER EVENT THIS WEEKEND. LATEST WV IMAGERY SHOWS LONGWAVE

TROUGH WITH EMBEDDED SHORTWAVES OVER CALIFORNIA. STRONG THETA E

ADVECTION WILL BE ONGOING ACROSS THE REGION AS THIS UPPER LEVEL

LOW EJECTS ACROSS THE FOUR CORNERS REGION. BY THE START OF THE

PERIOD TOMORROW MORNING...EXPECT TO HAVE +20C TEMPS AT 900MB WITH

CONTINUED WARM AIR ADVECTION THROUGHOUT THE DAY TOMORROW. THAT

WILL ACT TO CAP OFF THE SOUTHERN PART OF THE CWA...SO LOW

PROBABILITY OF CONVECTION NEAR THE IA/MO BORDER DESPITE SB CAPES

ON THE ORDER OF 3000J/KG. INSTEAD LOOKS LIKE THE BEST THREAT FOR

SEVERE WEATHER WILL BE NEAR THE WARM FRONT NORTH OF I80 AND ALONG

THE DRY LINE IN EASTERN NEBRASKA. DEPENDING ON THE EXACT

PLACEMENT...CONTINUED ISENTROPIC LIFT ALONG AND NORTH OF THE WARM

FRONT SHOULD BE ENOUGH TO BREAK OUT CONVECTION BY LATE

AFTERNOON/EARLY EVENING TOMORROW. GIVEN THE WIND PROFILES...ANY

STORMS THAT FIRE ARE LIKELY TO BE SUPER-CELLULAR IN NATURE WITH

ROTATING UPDRAFTS SUPPORTIVE OF LARGE HAIL. GIVEN THE LARGE CAPE

VALUES IN THE HAIL GROWTH ZONE...AM CONFIDENT THAT HAIL WILL BE

THE PRIMARY THREAT. AFTER SUNSET THE LOW LEVEL JET WILL KICK IN

ACROSS THE REGION WHICH WILL KEEP CONVECTION ONGOING THROUGH THE

OVERNIGHT HOURS.

ON SUNDAY THE SEVERE THREAT SHIFTS FURTHER EAST AS A SECONDARY

SURFACE LOW PRESSURE SYSTEM FORMS WITH THE ARRIVAL OF THE MAIN UPPER

LEVEL VORT MAX. THIS LOW IS FORECAST TO MOVE NE THROUGH SIOUX FALLS

SD ON SUNDAY. VERY WARM TEMPERATURES CAN BE EXPECTED ONCE AGAIN ON

SUNDAY WITH STRONG SOUTHERLY WINDS IN PLACE. CURRENTLY IT APPEARS

THAT WITH THE WARM FRONT WELL NORTH OF IOWA...BUT BEST CHANCE FOR

CONVECTIVE INITIATION WILL BE OUT AHEAD OF THE DRY LINE WHICH IS

FORECAST TO BE DRAPED ACROSS CENTRAL IOWA BY SUNDAY AFTERNOON. AS

THE AFOREMENTIONED UPPER LEVEL LOW MOVES ACROSS THE REGION ON

SUNDAY...THE CAP IS EXPECTED TO QUICKLY ERODE SUNDAY AFTERNOON WHICH

SHOULD LEAD TO SURFACE BASED SUPERCELLS CAPABLE OF PRODUCING LARGE

HAIL...STRONG WINDS...AS WELL AS TORNADOES. SREF08.09 SHOWS

90PERCENT PROBABILITY OF EFFECTIVE SHEAR OF 50KTS OR HIGHER SUNDAY

AFTERNOON. WITH 0-1KM HELICITY VALUES OF 100 ON AVERAGE. FEELING IS

THESE VALUES MAY BE UNDERDONE GIVEN THE 10MB PRESSURE FALLS ACROSS

NW IOWA SUNDAY AFTERNOON WHICH COULD CAUSE WINDS AT THE SURFACE TO

BACK MORE THAN INDICATED BY THE MODELS. REGARDLESS...THE POTENTIAL

FOR A HIGH END SEVERE WEATHER THREAT EXISTS THROUGH THE WEEKEND.

[prinsburg_wx]

from MPX

STRONG DEEP LOW LAYER SHEAR AND AMPLE MOISTURE TRANSPORT WILL PLACE

MUCH OF OUR EASTERN HALF OF THE FORECAST AREA FOR FAVORABLE LOCATION

FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY LATE SATURDAY INTO MONDAY

MORNING. SUNDAY AFTERNOON AND EVENING...APPEARS TO BE MORE PROMINENT

FOR MORE WIDESPREAD SEVERE WEATHER THREAT WITH MORE SURFACE INDUCED

AND MUCH OF THE FORECAST AREA IN THE WARM SECTOR. A FEW STRONG

TORNADOES COULD OCCUR EITHER NEAR THE WARM FRONT IN THE AFTERNOON OR

ALONG THE COLD FRONT AS THE LOW-LEVEL JET STRENGTHENS DURING THE

EARLY EVENING. THERE STILL REMAINS QUITE OF BIT OF UNCERTAINTY ON

HOW THINGS WOULD PLAY OUT OVER THE NEXT COUPLE OF DAYS...WITH

INITIAL CONVECTION OR EVOLUTION OF THUNDERSTORMS...ROBBING ANY

DECENT MOISTURE ADVECTION INTO OUR FORECAST AREA. THE LATEST MODEL

RUNS...SHOWED BITS OF PV ANOMALY LIFTING NORTHEAST AHEAD OF THE MAIN

LOBE SATURDAY AND SATURDAY NIGHT OVER THE FORECAST AREA.

[Srain]

tor-con, bore-con

You don't believe 'smart modeling'?

[Stebo]

grr must have decided to re-word the tornado paragraph, look now:

THERE IS A TORNADO ISSUE SUNDAY MORNING...ONCE THE SUN COMES UP AND

STARTS HEATING THE AIR ONCE AGAIN... THERE WILL BE THE POTENTIAL FOR

ISOLATED TORNADOES NEAR THE WARM FRONT (WHERE MOST OF SOUTHWEST

MICHIGAN TORNADOES HAPPEN). THIS FEATURE IS SHOWN NICELY BY THE SPC

09Z ENSEMBLE FORECAST FOR SIGNIFICANT TORNADOES (SCARY). GIVEN THE

HIGH SHEAR VALUES AND SIGNIFICANT CAPE IN PLACE NEAR THE WARM

FRONT...THIS WILL BE A REAL THREAT

Thanks I corrected my post.

[janetjanet998]

should we split off a thread just for Sunday? or even tomorrow too?(it can be merged back in later if needed)

It will be rather confusing to keep the current active today/tomorrow stuff and the sunday outbreak forecast seperate

I think that is what we did in the past a sperate thread for bigger day outbreaks..and a combined thread that covered days for late summer smaller outbreak

[SmokeEater]

should we split off a thread just for Sunday?(it can be merged back in later if needed)

It will be rather confusing to keep the current active today/tomorrow stuff and the sunday outbreak forecast seperate

IMO, if today turns out to be pretty decent, seperate all 3, but Saturday and Sunday should definitely be seperate.

[Thundersnow12]

The 850's look a bit better on the 18z NAM compared to the 12z run in western/southwest IA tomorrow evening, due south to slightly backed.

[SmokeEater]

Initiation North of Kingfisher, OK. From nothing to 40 dbz in one scan. Tops over 30,000 feet.

[Thundersnow12]

Initiation North of Kingfisher, OK. From nothing to 40 dbz in one scan. Tops over 30,000 feet.

beat me to it, alot of chasers dow there as well.

[JoMo]

Tornado Watch for OK/KS

[SmokeEater]

1st severe warning of the day. From nothing, to severe in what? 5 minutes? Impressive.

BULLETIN - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WARNING

NATIONAL WEATHER SERVICE NORMAN OK

536 PM CDT FRI APR 8 2011

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...

GARFIELD COUNTY IN NORTHERN OKLAHOMA...

SOUTHERN GRANT COUNTY IN NORTHERN OKLAHOMA...

* UNTIL 630 PM CDT

* AT 536 PM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED A SEVERE

THUNDERSTORM NEAR WAUKOMIS...MOVING NORTHEAST AT 25 MPH.

HAZARDS IN THE WARNING INCLUDE...

HAIL UP TO THE SIZE OF GOLF BALLS...

WIND GUSTS TO 60 MPH...

* LOCATIONS IN THE WARNING INCLUDE BISON...BRECKENRIDGE...

COVINGTON...DOUGLAS...ENID...FAIRMONT...GARBER...HAYWARD...

HUNTER...JEFFERSON...KREMLIN...LAMONT...MEDFORD...NORTH ENID...POND

CREEK...VANCE AIR FORCE BASE AND WAUKOMIS.