May 5-7th Plains/MW/GL/OV Severe Weather, SPC Risk Level: Day 1 Slight Risk - Forecasts & OBS Options

[wsushox1]

First week or so of May should be quiet however, there is the possibility for things to get more amplified and moisture should be available.

From ICT's Afternoon AFD.

000
FXUS63 KICT 012010
AFDICT

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE WICHITA KS
310 PM CDT SUN MAY 1 2011

.DISCUSSION...

....

EXTENDED...
A SERIES OF FRONTS WILL MOVE ACROSS THE FORECAST AREA DURING THIS
TIME FRAME. A WEAK COLD FRONT WILL MOVE INTO THE AREA AND WASH OUT
ON THURSDAY. MODELS TRY AND DEVELOP A WEAK MCS TO THE NORTH AND MOVE
SE ACROSS THE FAR EASTERN SECTIONS. A STRONGER MORE IMPRESSIVE
SYSTEM WILL MOVE ACROSS THE AREA ON SATURDAY AND GIVE US A LITTLE
BETTER CHANCE FOR THUNDERSTORMS. THE BEST INSTABILITY WILL LIE TO
THE EAST OF THE KANSAS TURNPIKE.

I AM A BIT INTRIGUED AT THIS POINT FOR A POSSIBLE SEVERE WEATHER
OUTBREAK EARLY NEXT WEEK. CAPE VALUES AT THIS TIME OVER SOUTHEAST
KANSAS ARE RUNNING UP TO 4600 JOULES PER KILOGRAM. THOUGH THE
CONVERGENCE ALONG THE BOUNDARY IS NOT VERY STRONG AT THIS TIME.
HOWEVER...IT IS WORTH WATCHING.

CH

Not quite sure why he mentioned "outbreak" but a decent event is definitely possible.

More to come later......

This thread atm, is Non SPC Based therefore SPC was left out of the Subtitile....feel free to add in once they throw something in in a 4-8 outlook.

I also know this is a decent ways in advance for severe wx, therefore I am just saying there is a general risk somewhere across the plains. People more advanced in forecasting have already mentioned things becoming more amplified near this timeframe, thus the need for a thread.

This post has been edited by wsushox1: May 1 2011, 06:07 PM

[jdrenken]

First week or so of May should be quiet however, there is the possibility for things to get more amplified and moisture should be available.

From ICT's Afternoon AFD.
Not quite sure why he mentioned "outbreak" but a decent event is definitely possible.

More to come later......

This thread atm, is Non SPC Based therefore SPC was left out of the Subtitile....feel free to add in once they throw something in in a 4-8 outlook.

I also know this is a decent ways in advance for severe wx, therefore I am just saying there is a general risk somewhere across the plains. People more advanced in forecasting have already mentioned things becoming more amplified near this timeframe, thus the need for a thread.

That's the beauty of it though. Since your local AFD mentioned it, it's worthy of a thread.

[Southern Indiana]

Just looked at PAH and Louisville, and no wording about severe weather, both mention instability but the fact that warming is going to occur in High Pressure has them thinking this area isnt going to see anything significant ATM.

[wsushox1]

Just looked at PAH and Louisville, and no wording about severe weather, both mention instability but the fact that warming is going to occur in High Pressure has them thinking this area isnt going to see anything significant ATM.

It is in the rather long range for Severe WX........and there is probably uncertainty in your area, as there is in mine as well.

18z GFS still keeps a Severe Threat around the I-35 corridor in OK and KS, so still need to be watching this TF.

[SEMIweather]

Something big will happen in this timeframe is my guess...not sure which day yet, but the models have been hinting at a threat for a while now.

[TJ Schulte]

Yeah even though we had 800 tornadoes last month we can't assume we're all done. By the looks of it we'll have a nice long break considering the jet stream turned into a machine gun in april. Lets see what May has in store other than consistent temps in the 60s

[jdrenken]

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0342 AM CDT MON MAY 02 2011

VALID 051200Z - 101200Z

...DISCUSSION...
A GENERALLY WNWLY FLOW REGIME IS FORECAST TO BE IN PLACE THROUGH
MUCH OF THE EXTENDED PERIOD...WITH MULTIPLE UPPER LEVEL SHORTWAVES
MOVING ACROSS THE CNTRL AND ERN STATES.

ON THU/D4...A LARGE AREA OF HIGH PRESSURE WILL COVER MUCH OF THE
CNTRL AND ERN CONUS WITH DRY LOW LEVEL TRAJECTORIES LIMITING
MOISTURE FOR INSTABILITY.

BY FRI/D5...MODELS ALREADY BEGIN TO DIVERGE WITH THE TIMING AND
LOCATION OF LOW AMPLITUDE SHORTWAVES. THE GFS ALREADY HAS A FEATURE
MOVING ACROSS THE NRN PLAINS WITH MORE ROBUST MOISTURE
RETURN...WHILE THE ECMWF IS FLATTER WITH THE FLOW...WITH SIGNS OF
MIXED OUT MOISTURE. THIS SEEMS REASONABLE GIVEN IT WILL BE EARLY IN
THE MOISTURE RETURN CYCLE.

A MORE ACTIVE PATTERN MAY BEGIN STARTING SAT/D6 THROUGH
MON/D8...WITH BETTER QUALITY LOW LEVEL MOISTURE STREAMING NWD ACROSS
THE PLAINS BENEATH GENERALLY NWLY FLOW ALOFT. THIS SHOULD FAVOR
DEVELOPMENT OF MESOSCALE CONVECTIVE SYSTEMS AFFECTING ANYWHERE FROM
THE CNTRL HIGH PLAINS EWD INTO THE MO AND OH VALLEYS. ALTHOUGH
PREDICTABILITY IS TOO LOW TO INTRODUCE ANY SEVERE AREAS...THE
PATTERN DOES APPEAR TO FAVOR CLUSTERS OF WIND AND HAIL BY NEXT
WEEKEND.

..JEWELL.. 05/02/2011

[wsushox1]

GFS seems off, it develops a deep area of low pressure in this timeframe across the Northern Plains with no upper level support though.

Doubtful of that at the moment.

[Southern Indiana]

Just looked at the AFD for an update.

LMX is still mentioning possibilities with a couple of strong storms due to shear/instability. Mainly Saturday Evening. Expected to be a short even with minimal significance ATM.

PAH has yet to use the word "Storm" for their weekend AFD. Just expects good ol fashion rain on Saturday. Im not sure if PAH has only one person do their AFD, but hes always got something interesting to say.

This post has been edited by Southern Indiana: May 2 2011, 09:49 PM

[jdrenken]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
859 PM CDT MON MAY 2 2011

.PREV DISCUSSION...
ISSUED 253 PM CDT MON MAY 2 2011

LONG TERM...FRIDAY THROUGH MONDAY

AFTER THURSDAY WAVE PASSES TO THE EAST...DRY WEATHER WILL BRIEFLY
RETURN FOR FRIDAY...BEFORE YET ANOTHER NORTHERN STREAM SYSTEM
APPROACHES ON SATURDAY. THIS NEXT FEATURE WILL HAVE A BIT MORE
MOISTURE TO WORK WITH...AND WITH STRONG WAA DEVELOPING AHEAD OF
ITS ASSOCIATED SURFACE LOW/FRONT...THINK SHOWERS/STORMS WILL
DEVELOP ACROSS THE AREA FRIDAY NIGHT. SCATTERED CONVECTION WILL
LINGER INTO SATURDAY AND SATURDAY NIGHT AS WELL...BEFORE THE LOW
AND COLD FRONT SWEEP THROUGH THE AREA. STILL SOME DIFFERENCES
AMONG THE MEDIUM RANGE MODELS FURTHER OUT IN THE EXTENDED...BUT
HAVE GENERALLY FOLLOWED THE ECMWF...WHICH HAS SHOWN A DISTINCT
SUPERIORITY TO THE GFS IN THE PAST COUPLE OF WEEKS. AS SUCH...THE
NEXT NORTHERN STREAM WAVE APPEARS TO REMAIN FURTHER NORTH ACROSS
THE UPPER MIDWEST/GREAT LAKES LATE IN THE WEEKEND. HAVE THEREFORE
MAINTAINED A DRY FORECAST FOR BOTH SUNDAY AND MONDAY.

BARNES

[jdrenken]

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
750 PM CDT MON MAY 2 2011

.DISCUSSION...
/325 PM CDT MON MAY 2 2011/

A MODERATION IN TEMPERATURES IS EXPECTED ON WEDNESDAY AS THE HIGH
RETREATS AND A RETURN OF S/SWLY LOW LEVEL FLOW AND WAA WILL GET
WELL UNDERWAY ON WEDNESDAY NIGHT. THIS WAA COMBINED WITH SOME
STEEPER MID LEVEL LAPSE RATES COULD HELP GENERATE SOME ELEVATED
SHOWERS OR THUNDERSTORMS LATE WED NIGHT ACROSS PARTS OF NE MO AND
WEST CENTRAL IL...IN ADVANCE OF THE NEXT UPPER TROF. THIS NEXT
UPPER TROF AND THE ASSOCIATED SFC COLD FRONT WILL IMPACT THE AREA
ON THURS/THURSDAY NIGHT. THE NAM IS MUCH SHARPER WITH THE UPPER
TROF AND COLD AIR ALOFT AND HENCE INSTABILITY...SUPPORTIVE OF
STRONG THUNDERSTORMS WITH SMALL HAIL. THE GFS IS NOT QUITE AS
BULLISH. WE SHOULD SEE SCATTERED SHOWERS AND THUNDERSTORMS WITH
THIS SYSTEM...BUT THE JURY IS STILL OUT ON THE INTENSITY.

ANOTHER TROF AND SFC FRONT WILL BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS THIS WEEKEND. DEPENDING ON THE DETAILS OF THE UPPER
AIR PATTERN...YET ANOTHER ROUND OF STORMS IS POSSIBLE MON-TUES.

GLASS

[WeatherMonger]

95% done with my move and getting my house situated. Missed the outbreak down South, terrible situation. Ready to hear some thunder up this way again. Seems like forever now

Sounds like the dates may need extended and/or pushed back a few days

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 AM CDT TUE MAY 03 2011

VALID 061200Z - 111200Z

...DISCUSSION...
ON FRI/D4...MOISTURE WILL BEGIN TO RETURN NWD INTO THE SRN PLAINS AS
A WEAK LEE TROUGH DEVELOPS DURING THE DAY BENEATH A WEAK NWLY FLOW
ALOFT. FORECAST SOUNDINGS INDICATE THAT WHILE STRONG HEATING MAY
RESULT IN CONVECTION ALONG THE DRYLINE...ACTIVITY MAY NOT BE
PARTICULARLY SEVERE WITH ONLY 50S DEWPOINTS AND CAPPING CONCERNS.
ADDITIONAL DEVELOPMENT COULD OCCUR OVER THE MID MO/UPPER MS VALLEY
FRIDAY NIGHT DRIVEN BY A LOW LEVEL JET...BUT MODELS DO NOT AGREE ON
THE LOCATION AND MAGNITUDE OF THE FORCING MECHANISMS.

THIS PATTERN IS FORECAST TO PERSIST THROUGH DAY 5...BUT
PREDICTABILITY AND OVERALL POTENTIAL DO NOT WARRANT SEVERE AREAS AT
THIS TIME.

ALTHOUGH THERE ARE DIFFERENCES IN THE GUIDANCE...THEY DO AGREE THAT
BEGINNING ON SUN/D6...A LARGER SCALE TROUGH WILL DEVELOP ACROSS THE
WRN STATES...WITH RIDGING DEVELOPING AHEAD OF THIS TROUGH OVER THE
PLAINS STATES. THIS WOULD PORTEND A GREATER SEVERE THREAT...WITH THE
POSSIBILITY OF 3-4 CONSECUTIVE DAYS OF SIGNIFICANT SEVERE DEVELOPING
FROM THE PLAINS STATES INTO THE MIDWEST BEGINNING ON MON/D7 INTO
TUE/D8 AND LIKELY EXTENDING INTO D9. IF TREND IN MODEL GUIDANCE
PERSISTS...SEVERE RISK AREAS WILL LIKELY BE FORTHCOMING IN
SUBSEQUENT D4-8 OUTLOOKS.

..JEWELL.. 05/03/2011

[wsushox1]

95% done with my move and getting my house situated. Missed the outbreak down South, terrible situation. Ready to hear some thunder up this way again. Seems like forever now

Sounds like the dates may need extended and/or pushed back a few days

More than likekly

[Southern Indiana]

95% done with my move and getting my house situated. Missed the outbreak down South, terrible situation. Ready to hear some thunder up this way again. Seems like forever now

Sounds like the dates may need extended and/or pushed back a few days

Ive got a couple of buddies coming in from out of town for a fishing weekend. No sever weather the first half of saturday and I am good.

LMX

Area Forecast Discussion
Issued by NWS Louisville, KY


.LONG TERM (WEDNESDAY - MONDAY)...

UPSTREAM UPR LEVEL/SURFACE RIDGES WILL KEEP US DRY THRU THU AS THEY
MOVE INTO AND REACH THE EASTERN OHIO VALLEY. TEMPS WILL REBOUND...
ESPECIALLY THU AS WINDS BECOMES SOUTHERLY.

UPPER LEVEL TROF ACRS THE MID/UPPER MS VLY THU EVE EXPECTED TO REACH
THE LOWER OH VLY BY FRI MORNING AND BRING A CHANCE OF SHOWERS THU
NIGHT AND EARLY FRI. ANY SHOWERS SHUD BE EXITING OUR EASTERN
FORECAST AREA BY EARLY AFTN FRI. A BREAK IN RAIN EXPECTED FRI
AFTN/NIGHT BEFORE NEXT SYSTEM (UPPER LEVEL TROF/LOW TRAVERSING THE
GREAT LAKES) SENDS A COLD FRONT OUR WAY FOR THE WEEKEND.

IT APPEARS THAT THE BULK OF THE SHOWER/TSTM ACTIVITY ASSOCIATED WITH
THIS SYSTEM WILL RESIDE ACRS SOUTHERN INDIANA SAT...THEN SLIDE SEWD
INTO N AND ECNTRL KY SAT NIGHT. FORECAST SOUNDINGS INDICATE AMPLE
SHEAR/INSTABILITY FOR SOME STRONG STORMS EARLY SAT NIGHT.

SHOWERS/STORMS SHUD BE WANING BY SUN AS FRONT DECELERATES/STALLS IN
CENTRAL KY.

TEMPS EXPECTED TO BE ABOVE SEASONAL MAXS FOR THE WEEKEND IN
PRE-FRONTAL S/SW FLOW.

[Southern Indiana]

Ive got a couple of buddies coming in from out of town for a fishing weekend. No sever weather the first half of saturday and I am good.

LMX

And PAH didnt even bother to mention anything after Thursday in the current AFD

[Superstorm93]

6z GFS looked pretty impressive for next week. Should be an interesting time.

Sunday:



Monday:

[Chicago Storm]

This topic covers two systems...

6-7th and the 8-11th...needs to be broken up.

[SEMIweather]

NAM wants to break the cap Saturday Evening although I'm not sure why because I don't see a trigger. Still if the cap does break there would be enough instability to support a threat of severe weather.

[WeatherMonger]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1045 AM CDT SAT MAY 7 2011

.DISCUSSION...
ISSUED 1045 AM CDT SAT MAY 7 2011

SPC IS GOING TO UPGRADE OUR EASTERN IL COUNTIES INTO A SLIGHT RISK
OF SEVERE THUNDERSTORMS THIS AFTERNOON. ATMOSPHERE GETTING MORE
UNSTABLE THAN EARLIER EXPECTED WITH CLOUDS DECREASING QUICKER FROM
THE WEST AND ALSO HAVE WIND SHEAR.

SHOWERS AND ISOLATED THUNDERSTORMS DIMINISHING EAST OF I-57 LATE
THIS MORNING...WHILE CLOUDS DECREASE AS TO I-57. 15Z/10 AM SURFACE
MAP SHOWS 1005 MB LOW PRESSURE OVER CENTRAL IA WITH ITS COLD FROTN
EXTENDING TO 1004 MB LOW PRESSURE OVER NORTH CENTRAL OK. A WARM
FRONT EXTENDED EAST FROM THE LOW IN CENTRAL IA ACROSS NORTHERN
IL NEARING I-80. DEWPOINTS IN THE LOW TO MID 50S OVER CENTRAL/SE
IL. TEMPS RANGED FROM THE MID TO UPPER 50S ALONG THE INDIANA
BORDER WHERE ITS STILL CLOUDS AND SOME SHOWERS LINGERING...WHILE
LOWER 70S FROM JACKSONVILLE SW.

HIGH RESOLUTION MODELS BRING LOW PRESSURE FROM CENTRAL IA EAST
ACROSS CENTRAL IL DURING THIS AFTERNOON AS FRONTAL BOUNDARY NEAR
I-80 SLIPS BACK SOUTH TOWARD I-74. EXPECTED ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP THIS AFTERNOON ESPECIALLY
FROM I-74 NE AND EAST OF I-55. A FEW STORMS COULD BECOME STRONG TO
SEVERE WITH LARGE HAIL AND DAMAGING WIND GUSTS FROM MID AFTERNOON
INTO EARLY EVENING. HIGHS IN THE LOW TO MID 70S LOOK ON TRACK
TODAY WITH WARMEST READINGS FROM SPRINGFIELD SW.

HUETTL

[WeatherMonger]