January 28-30 Severe Threat

[Hoosier]

Models have been showing a wave on the front moving into IL later Tuesday. That will have to be watched as it could serve to prevent the low level flow from veering.

[Hoosier]

LOT mentioned something interesting. Gino said it was the first January day 3 slight risk that he could recall for the area:

WHILE IT WOULD BE VERY RARE...CANNOT COMPLETELY RULE OUT A SEVERE THREAT IN THE AREA TUESDAY AS THE UNSEASONABLY HIGH DEW POINTS COULD RESULT IN WEAK (BUT SUFFICIENT) INSTABILITY TO SUPPORT SEVERE THUNDERSTORMS IN AN ENVIRONMENT OF VERY STRONG SHEAR AND INCREASING LARGE SCALE ASCENT. THE NEW SWODY3 OUTLOOK JUST CAME OUT AND HAS INCLUDED A SLIGHT RISK INTO OUR CWA TUESDAY AND AS BEST I CAN RECALL THIS MAY BE THE FIRST EVER DAY 3 SLIGHT RISK IN OUR CWA IN JANUARY.

[Hoosier]

12z GFS still has that ~100 kt max at 850 mb. Would be cool to see that happen...watching the clouds would be like watching a time lapse video.

[Tim from Springfield (IL)]

ILX:

 

WITH AREA REMAINING IN A WARM SECTOR AND SOUTHERLY WINDS BRINGING CONTINUED MOISTURE AND WAA INTO THE REGION...CHANCE OF SHOWERS WILL CONTINUE OVERNIGHT AND INTO TOMORROW. LATE TOMORROW NIGHT THE FRONT TO THE NORTHWEST WILL BECOME A LITTLE ACTIVE WITH CONVECTION SO HAVE INCLUDED A CHANCE OF THUNDERSTORMS WITH THE SHOWERS FOR MON NIGHT. THE THREAT OF THUNDERSTORMS WILL CONTINUE INTO TUE AND TUE NIGHT AS THE FRONT MOVES INTO THE STATE. SPC NOTICING THIS TOO AND HAS INCLUDED MOST OF THE CWA...EAST OF THE ILLINOIS RIVER...IN A SLIGHT RISK FOR TUE INTO TUE NIGHT. ALL MODELS TRACK A LOW PRESS AREA SOMEWHERE ACROSS OUR CWA DURING THIS PERIOD. SO SHOULD BE FAVORABLE WIND FIELD FOR STRONG SQUALL LINE TO FORM AND MOVE ACROSS THE AREA. SPC DISCUSSION MENTIONS THIS ALONG WITH EMBEDDED SUPERCELLS IN THE LINE. WILL CONTINUE TO MONITOR THIS DEVELOPING SITUATION. AS THE FRONT MOVES THROUGH TUE NIGHT COLDER AIR WILL ADVECT INTO THE REGION AND CHANGE THE PCPN TO A MIX OF RAIN AND SNOW AND THEN ALL SNOW ON THE VERY FAR BACK SIDE. AT THIS TIME...SNOW ACCUMULATIONS ARE TOO UNCERTAIN TO MENTION. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY UPPER LEVEL PATTER BECOMES NORTHWESTERLY FOR THE EXTENDED PERIOD AND MODELS SHOW TWO WEAK WAVES THAT MOVE THROUGH THE AREA IN THIS FLOW. CURRENT INDICATIONS ARE THAT THERE WILL NOT BE A LOT OF MOISTURE TO WORK WITH AND THE STRONGEST PART OF THE WAVES WILL BE TO THE NORTH. SO FOR NOW WILL JUST HAVE A DRY FORECAST THROUGH REST OF THE WEEK AND INTO THE WEEKEND. TEMPS WILL TURN VERY COLD FOR THUR NIGHT AND FRIDAY...BUT THEN BEGIN TO WARM BACK UP TO ABOVE FREEZING BY THE WEEKEND. AUTEN && .CLIMATE... ISSUED 318 PM CST SUN JAN 27 2013

 

RECORD HIGH TEMPS FOR TUESDAY JAN 29 PEORIA.........61 SPRINGFIELD....64 LINCOLN........64 URBANA.........61 NORMAL.........63 DECATUR........67 EFFINGHAM......66 GALESBURG......56

[Tim from Springfield (IL)]

LOT mentioned something interesting. Gino said it was the first January day 3 slight risk that he could recall for the area:

WHILE IT WOULD BE VERY RARE...CANNOT COMPLETELY RULE OUT A SEVERE THREAT IN THE AREA TUESDAY AS THE UNSEASONABLY HIGH DEW POINTS COULD RESULT IN WEAK (BUT SUFFICIENT) INSTABILITY TO SUPPORT SEVERE THUNDERSTORMS IN AN ENVIRONMENT OF VERY STRONG SHEAR AND INCREASING LARGE SCALE ASCENT. THE NEW SWODY3 OUTLOOK JUST CAME OUT AND HAS INCLUDED A SLIGHT RISK INTO OUR CWA TUESDAY AND AS BEST I CAN RECALL THIS MAY BE THE FIRST EVER DAY 3 SLIGHT RISK IN OUR CWA IN JANUARY.

 

Wow.  And just for perspective, this is the Day 3 outlook from Jan. 5, 2008 (for 1/7/08)--which would eventually spawn the Lawrence EF3 in Boone and McHenry counties two days later:

 

http://www.spc.noaa.gov/products/outlook/archive/2008/day3otlk_20080105_1100.html

[PatrickSumner]

Wow. And just for perspective, this is the Day 3 outlook from Jan. 5, 2008 (for 1/7/08)--which would eventually spawn the Lawrence EF3 in Boone and McHenry counties two days later:

http://www.spc.noaa.gov/products/outlook/archive/2008/day3otlk_20080105_1100.html

What does the below statement mean from IWX?

TIMING OF POTNL TSRA APPEARS

GRTST WITH VERY HEAVY RAFL RATES TUE AFTN INTO ERLY TUE NIGHT COINCIDENT WITH STRONG LLVL CONVERGENCE ENSUES ON NRN TERMINUS OF LLVL JET FM SRN CWA AT 00 UTC WED WITH CONCENTRATED 50-60KT FLOW

BURGEONING TO 65-70KTS BY 06 UTC...THEN VEERING WELL OUT INTO THE

LWR GRTLKS BY DAYBREAK WED...WITH NUMEROUS SMALL SCALE MESOVORTS

LKLY PER HIER RES ANALYSIS EJECTING ALONG FNTL BNDRY.

[Hoosier]

Some of the forecast soundings for Tue/Tue night are really impressive in terms of shear. 18z GFS has a pretty large area of 0-3 km helicity of 800-1200 and 0-1 km shear of 50-70 kts. Big question continues to be instability.

[IWXwx]

Some of the forecast soundings for Tue/Tue night are really impressive in terms of shear. 18z GFS has a pretty large area of 0-3 km helicity of 800-1200 and 0-1 km shear of 50-70 kts. Big question continues to be instability.

I'm liking that low level shear, now if we can get ANY cape, we're in the game. I'm not speaking so much about MBY, but I want to see something at this latitude in January.

[Hoosier]

Terre Haute sounding off the GFS.  Not much CAPE and it's very skinny but this kind of shear in the warm sector gets my attention

 

 

[Thundersnow12]

Strength of that sfc low as is moves into MO is going to be key and how deepening you get as that will determine how much backing of the surface flow you get.

 

All dependent on how much instability you get.

 

Northeast AR up to STL look interesting.

[ukrocks]

I'm excited about the potential of this event. Wind fields and shear are impressive for late January.

[Hoosier]

00z NAM seems a bit stronger with low level wind fields. It has an area of 850 mb winds of 85-90 kts early Wed so just shy of the GFS.

[csnavywx]

Use virtual temp soundings from Twisterdata to get a better idea with the CAPE. It's there and it's sufficient for at least decent thunderstorm activity. Tonight's storms over the cool sector was a good sign as far as the quality of the warm air mass is concerned. All that is needed are a few breaks of sun on Tuesday and this could be the difference between a notable event and one to remember.

[Stebo]

Use virtual temp soundings from Twisterdata to get a better idea with the CAPE. It's there and it's sufficient for at least decent thunderstorm activity. Tonight's storms over the cool sector was a good sign as far as the quality of the warm air mass is concerned. All that is needed are a few breaks of sun on Tuesday and this could be the difference between a notable event and one to remember.

 

Completely agree here, I think people are underscoring this potential as the models aren't showing impressive CAPE, you really don't need much CAPE this time of year for things to go in a big way.

[csnavywx]

One concern I do have is that the shear values start getting pretty nutty during the evening; it becomes enough to start shearing apart some "unshielded" updrafts after 00Z. By unshielded I mean those storms outside the main line/QLCS who are exposed to the full brunt of those mid-level winds.

[Hoosier]

One concern I do have is that the shear values start getting pretty nutty during the evening; it becomes enough to start shearing apart some "unshielded" updrafts after 00Z. By unshielded I mean those storms outside the main line/QLCS who are exposed to the full brunt of those mid-level winds.

What's your take on the level of nocturnal threat north of the Ohio River? I just can't help but be skeptical/very conservative about nocturnal severe weather in January.

[Stebo]

What's your take on the level of nocturnal threat north of the Ohio River? I just can't help but be skeptical/very conservative about nocturnal severe weather in January.

 

It's hard not to be skeptical, however with the amount of WAA that is progged to occur Tuesday evening, the temperatures/dew points should remain steady until the front slams home. Certainly the forcing and winds are there, the question will be if any instability can sustain itself through the evening hours/overnight.

[csnavywx]

It's going to get pretty sketchy for severe E of IL and N of the Ohio River. Best time for severe looks to be immediately preceding and within the first 3 hours of QLCS formation. As far as your location is concerned, I'd expect a thin snaky (slowly weakening) forced line embedded in a larger area of mod-heavy rain and thunder. Most of the instability is elevated by the time it gets that far east. You could still see some of those robust low level winds get transported down.

[csnavywx]

It's going to get pretty sketchy for severe E of IL and N of the Ohio River. Best time for severe looks to be immediately preceding and within the first 3 hours of QLCS formation. As far as your location is concerned, I'd expect a thin snaky (slowly weakening) forced line embedded in a larger area of mod-heavy rain and thunder. Most of the instability is elevated by the time it gets that far east. You could still see some of those robust low level winds get transported down.

I should note that this is heavily timing-based. If it comes in 3 hours faster, all bets are off.

[Hoosier]

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1130 AM CST MON JAN 28 2013

VALID 291200Z - 301200Z

..THERE IS A MDT RISK OF SVR TSTMS FROM NRN LA CNTRL AND ERN AR...EXTREME SWRN TN AND NWRN TO WCNTRL MS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN PLAINS...LOWER THROUGH MID MS VALLEY INTO WRN PARTS OF THE TN AND OH VALLEYS...

..SYNOPSIS

THE HIGH AMPLITUDE UPPER TROUGH NOW OVER THE WRN U.S. WILL ADVANCE EWD...WITH MODEL CONSENSUS INDICATING THAT THE TROUGH AXIS WILL BE LOCATED FROM MN THROUGH CNTRL/ERN TX BY THE END OF THIS PERIOD. MID LEVEL JET AND ATTENDANT VORT MAX LOCATED WITHIN BASE OF THE TROUGH SHOULD EJECT FROM THE SRN PLAINS THROUGH THE LOWER-MID MS VALLEY TUESDAY NIGHT. AS THIS OCCURS A CYCLONE WILL DEEPEN AND LIFT NEWD THROUGH THE MID MS VALLEY REGION. A POLAR FRONT WILL EXTEND FROM THE SFC LOW OVER IA SWWD INTO CNTRL/SRN HIGH PLAINS EARLY TUESDAY...WITH A PACIFIC FRONT/DRYLINE EXTENDING SWD THROUGH WRN TX. POLAR FRONT WILL ADVANCE SEWD DURING THE DAY...WHILE THE PACIFIC FRONT SURGES EWD AND MERGES WITH DRYLINE...CONTINUING THROUGH THE LOWER MS VALLEY OVERNIGHT.

..SRN PLAINS THROUGH LOWER MS VALLEY REGION

POTENTIAL EXISTS FOR A SIGNIFICANT SEVERE WEATHER EVENT TUESDAY WITH DAMAGING WIND AND TORNADOES THE PRIMARY THREATS...ESPECIALLY DURING THE EVENING AND OVERNIGHT IN MODERATE RISK AREA. OBSERVATIONS SHOW A RESERVOIR OF MIDDLE TO UPPER 60S DEWPOINTS FROM CNTRL INTO SRN TX. SLY BOUNDARY LAYER FLOW ALREADY EXISTS FROM THE SRN PLAINS INTO THE LOWER MS VALLEY AND WILL STRENGTHEN TUESDAY IN ASSOCIATION WITH AN INTENSIFYING LLJ. WIDESPREAD MULTI-LAYER CLOUDS WILL LIMIT BOUNDARY LAYER WARMING DURING THE DAY. HOWEVER...MID 60S DEWPOINTS SHOULD ADVECT AS FAR NORTH AS SERN OK INTO CNTRL AR AND NRN MS BENEATH A PLUME OF 6.5 C/KM MID LEVEL LAPSE RATES RESULTING IN AT LEAST 500-1000 J/KG MLCAPE.

STORMS ARE EXPECTED TO DEVELOP WITHIN PRE-FRONTAL CONFLUENCE BAND ACROSS CNTRL/ERN OK INTO NCNTRL/NERN TX EARLY TUESDAY AND SHIFT EWD AND NEWD DURING THE DAY. OTHER STORMS MAY DEVELOP FARTHER SOUTH THROUGH ERN TX DURING THE AFTERNOON ALONG MERGING PACIFIC FRONT AND SHIFT EWD THROUGH THE LOWER MS VALLEY. THE BOUNDARY LAYER WILL MOISTEN SUFFICIENTLY FOR THIS ACTIVITY TO BECOME SFC BASED. STORMS WILL BE EMBEDDED WITHIN STRONG DEEP LAYER FLOW WITH A 50+ KT SLY LLJ AND MID LEVEL WINDS INCREASING TO 80 KT. STORMS ARE EXPECTED TO EVOLVE INTO A PREDOMINANT QLCS WITH EMBEDDED SUPERCELL AND BOWING SEGMENTS POSING A RISK FOR DAMAGING WIND AND TORNADOES. TORNADO THREAT MAY INCREASE OVERNIGHT...ESPECIALLY IN MODERATE RISK AREA WHERE LLJ INTENSIFYING TO IN EXCESS OF 70 KT WILL BE COLLOCATED WITH NRN EDGE OF MID 60S DEWPOINTS.

..UPPER MS VALLEY THROUGH TN VALLEY REGION

OTHER STORMS WILL EXPAND NEWD THROUGH THE MID MS VALLEY AND SWRN PARTS OF OH VALLEY WHERE INSTABILITY WILL BE MORE LIMITED...BUT SUFFICIENT FOR A THREAT FOR DAMAGING WIND WITH PRIMARY MODE BEING LINES AND BOWING SEGMENTS WITH MESO VORTICES. A FEW EMBEDDED SUPERCELLS WILL ALSO BE POSSIBLE GIVEN SIZE OF HODOGRAPHS AND STRENGTH OF DEEP LAYER FLOW/SHEAR SUGGESTING A FEW TORNADOES CANNOT BE RULED OUT.

..DIAL.. 01/28/2013

[LouWX]

Pretty quiet in this topic which surprises me. I guess everyone is in winter mode still.

SPC has expanded SLGT risk into Indiana and I think that expansion will continue. Dew points near 60 south of I 70 and especially along the OH River looks sufficient to bring down some of that 80+kt LLJ and I would say we will see some TOR warnings with the radar showing some couplets in the QLCS. Not sure if LL CAPE is enough to get those to touch down but with nocturnal event it'll be tough job for NWS offices.

Pretty strong gradient winds ahead of this thing too Tues night!!

[Hoosier]

It'll be fun watching the velocity products with this rip roaring LLJ tomorrow night. Probably going to see some very intense velocities on some of the scans...question is how much can make it down to the surface.

[B-Rent]

It'll be fun watching the velocity products with this rip roaring LLJ tomorrow night. Probably going to see some very intense velocities on some of the scans...question is how much can make it down to the surface.

Question #2: How much will the Wabash suck up. 

[Hoosier]

Temps overachieving in Missouri right now (70s as far north as I-70). This will be important to watch tomorrow.

[Fickle Heights]

I saw NWS has Lafayette's dew point reaching 57 degrees tomorrow. I did some digging and found the highest dew point recorded in January (since 1973) is 61 on Jan. 5, 1997. The last time was had dew points in the upper 50s here in January was during the flooding event in 2008.

[Chicago WX]

I saw NWS has Lafayette's dew point reaching 57 degrees tomorrow. I did some digging and found the highest dew point recorded in January (since 1973) is 61 on Jan. 5, 1997. The last time was had dew points in the upper 50s here in January was during the flooding event in 2008.

 

Good stuff.

 

Some recent times high dewpoint readings...

 

Pulled off a 55º at LAF last January on the 17th. 1.46" of rainfall that day.

 

56º on January 1, 2011. That one ate all of our snow from December 2010.

[Chicago Storm]

Near 60F DP's already making up as far north as IKX in C. IL.

[Natester]

You know that a squall line event occured 5 years ago on January 29, 2008.  That cold front had a wicked temperature gradient.  Here's a screenshot that I saved on my computer.

 

 

Only exception of tomorrow's event is that the temperatures will be warmer and that the temperature gradient won't be as sharp.  I could be wrong though.

[Chicago Storm]

For the LOT portion of the risk...

 

TEMPS WILL ONLY BE ONE PARAMETER TO BE CONCERNED WITH TUE...AS
ABUNDANT MOISTURE AND IMPRESSIVE LLVL SPEED/DIRECTIONAL SHEAR ARE
POISED TO PUSH OVERHEAD. AT THIS TIME SPC CONTINUES TO HAVE THE
SOUTH/SOUTHEAST PORTIONS OF THE CWFA PROGGED FOR A SLIGHT RISK OF
SEVERE WEATHER TUE. GIVEN SUCH A DYNAMIC AND CONTRASTING AIRMASS
BETWEEN THE WARM/MOIST AND COLD...THIS APPEARS TO BE SUCH AN
ANOMALOUS SETUP THAT IT WOULDN/T BE TOO MUCH OF A SURPRISE FOR
SEVERE WEATHER TO OCCUR. THE LARGEST CONCERN IS FOR DAMAGING
WINDS...ALTHOUGH WITH THE STRONG DIRECTIONAL LLVL SHEAR AND A MOIST
BOUNDARY IN THE VICINITY OF THE CWFA...A FEW THUNDERSTORM CORES
COULD SEE ROTATING UPDRAFTS. WHICH OPENS THE DOOR FOR AN ISOLATED
TORNADO TUE AFTN. WHILE THE FIRST HALF OF TUE LOOKS TO BE
QUIET...THINGS WILL RAPIDLY CHANGE FOR THE AFTN/EVE HOURS AS THE
SHORTWAVE APPROACHES FROM THE WEST. 

[BowMeHunter]

this should bring the chasers out scurrying around like COC roaches