Jan. 22-23 Plains/MW/OV Severe Weather, SPC Risk Level: Day 1 Moderate Risk - Forecasts & OBS Options

[31B militaryPoli...]

Wording from SPC:

FOR THE D7-D8 TIME FRAME...MODELS INDICATE A LARGER SCALE TROUGH
DEVELOPING OVER THE WRN SATES...WHICH WILL MOVE INTO THE PLAINS.
WHILE THIS LARGE SCALE FLOW REGIME WILL HAVE A GREATER CHANCE OF
MOISTURE RETURN OVER THE PLAINS...PREDICTABILITY REMAINS LOW.

Hope this isn't premature, but this dynamic system that's been consistently shown on the models especially the GFS, is quickly peaking my interest. You can't over look the dynamics and parameters associated with this system. GFS been consistent with a low-amplitude negative tilt trough moving through the Plains with deepening surface low tracking towards the GL region. The Gulf will be wide open in advance of this developing system with 60 Tds expanding up into portions of the Ohio Valley. As the system deepens low-level jet really ramps up with upwards of 70Kt jet at 850MB, AOA 60Kt jet at 500MB including a 110Kt jet streak at 300MB. Plenty of time to watch the models, but if the 18Z GFS is correct this could be the first significant severe weather event of the new year.







This post has been edited by 31B militaryPolice: Jan 16 2012, 08:57 PM

[andyhb]

Yeah, members on forums all over the place have been mentioning this thing, the run to run model consistency (particularly the Euro) is impressive, even more so is the type of threat that the 18z GFS is suggesting this far out, in terms of thermodynamics and shear...

[jdrenken]

Since you included the SPC disco, you are fine in creating the thread.

[Gilbertfly]

HPC...

[31B militaryPoli...]

The 12Z Euro now ejects the system into the middle of the country instead of burying the low in the SW like it's been doing. While not as potent of a system as the GFS it is a step in that direction. One thing to note is the 12Z GFS doesn't bring the 60 Tds as far north as the yesterday's 18Z and 0Z runs.

[StormChaserCK19]

Guys, this thread needs to get rolling! This looks like it could easily be the first SIGNIFICANT severe weather outbreak of the year. Check some of this stuff out...

Huntsville, AL AFD

MUCH OF SUNDAY WILL BE RELATIVELY UNEVENTFUL WEATHER-WISE AS THE NEXT
WEATHERMAKER APPROACHES THE AREA FROM THE WEST. THIS UPPER LEVEL
SYSTEM IS CONSIDERABLY STRONGER /AND UNUSUALLY STRONG FOR THIS TIME
OF YEAR/...AND WILL PROVIDE THE AREA WITH THE SECOND AND FINAL ROUND
OF STRONG TO SEVERE STORMS THIS WEEKEND. SHOWERS WILL BE POSSIBLE
ACROSS THE AREA SUNDAY MORNING AND AFTERNOON AS A STRONG COLD FRONT
NEARS THE REGION LATE SUNDAY EVENING. A WIND ADVISORY MAY BE NEEDED
SUNDAY AS THE SYSTEM APPROACHES AND THE PRESSURE GRADIENT TIGHTENS
ACROSS THE AREA. 850MB WINDS ~60KTS WILL TRANSLATE TO A DAMAGING
WIND THREAT SUNDAY NIGHT INTO MONDAY...ALONG WITH HELICITIES BETWEEN
300-500M2/S2. HODOGRAPHS SHOW AMPLE LOW LEVEL SHEAR IN PLACE...
TRANSLATING TO A HIGHER TORNADO THREAT THAN THE FIRST ROUND. MOST
LIKELY...A QLCS WILL SWEEP ACROSS THE AREA OVERNIGHT SUNDAY INTO
MONDAY...WITH STRONG TO SEVERE STORMS POSSIBLE AHEAD OF THE LINE OF
STORMS. SPC HAS A SLIGHT RISK OUTLOOKED FOR THE ENTIRE AREA DURING
THIS TIME. DAMAGING WINDS AND LARGE HAIL WILL BE THE PRIMARY
THREAT...WITH TORNADOES BEING THE SECOND THREAT. HEAVY RAINFALL WILL
LIKELY NOT BE AN ISSUE DUE TO THE QUICK PACE OF THE SYSTEM...BUT
DEPENDING ON EXACTLY HOW MUCH RAIN FALLS TONIGHT...ANY ADDITIONAL
RAINFALL WILL ONLY AGGRAVATE ONGOING FLOODING CONCERNS.

THE SFC COLD FRONT ITSELF AND UPPER TROF WILL SWING THROUGH DURING
THE DAY MONDAY...WITH SFC RIDGING AND RIDGING ALOFT BUILDING INTO THE
AREA. DRY WEATHER IS ANTICIPATED FOR MONDAY NIGHT INTO TUESDAY...AS
ANOTHER SYSTEM APPROACHES FOR MID-TO-LATE-WEEK. GIVEN THE EMPHASIS ON
THE SHORT-TERM PORTION OF THE FORECAST...NOT MANY CHANGES WERE MADE
TO THE EXTENDED PORTION OF THE FORECAST. GENERALLY AN UNSETTLED AND
ABOVE-AVERAGE TEMPERATURES ARE EXPECTED DURING THIS TIME.

Memphis, TN AFD

SUNDAY THROUGH MONDAY...MODELS ARE FAIRLY GOOD AGREEMENT THAT A
MUCH STRONGER SHORTWAVE TROUGH WILL CROSS THE CENTRAL AND SOUTHERN
PLAINS DURING THIS PERIOD SHIFTING FROM A POSITIVE TO NEGATIVE
TILT AS IT CROSSES THE OZARKS. ON THE SURFACE CONDITIONS WILL
START OFF COOL SUNDAY MORNING...HOWEVER AS THE TROUGH APPROACHES
SOUTHERLY LOW LEVEL FLOW WILL INTENSIFY RAPIDLY BY MIDDAY AND
THROUGH THE AFTERNOON...WITH A WARM SECTOR EXPECTED TO REACH THE
LOWER OHIO RIVER VALLEY BY 23/00Z. TEMPERATURES ARE PROGGED TO
CLIMB BACK INTO THE 60S WITH DEWPOINTS ALSO REACHING THE UPPER 50S
TO LOW 60S. THE EURO SHOWS MORE FAVORABLE LAPSE RATES IN THE 6.5
TO 7C RANGE STARTING LATE SUNDAY AFTERNOON THROUGH THE EVENING HOURS.
LOW LEVEL FLOW ALSO APPEARS MORE BACKED AS A 995MB SFC LOW MOVES
NORTHEAST ACROSS MISSOURI. THE ONLY MODEL DIFFERENCES IS THE GFS
AND NAM SHOW A FASTER SYSTEM WITH A LESS INTENSE SFC LOW. THIS
PLACES CONVECTION INITIATION NEAR THE TENNESSEE RIVER VALLEY
INSTEAD OF EURO SOLUTION IN CENTRAL/EASTERN ARKANSAS. HAVE LEANED
TOWARDS THE SLOWER EURO SCENARIO WHICH HAS BEEN MORE CONSISTENT
WITH THIS WEEKEND STORM OVER THE PAST FEW DAYS. THEREFORE A
GREATER THREAT OF SEVERE WEATHER IS LIKELY FOR THE MIDSOUTH LATE
SUNDAY WITH A HIGHER TORNADO POTENTIAL. THE SHORTWAVE WILL
QUICKLY LIFT NORTHEAST OF THE AREA EARLY MONDAY MORNING WITH
BREEZY WEST WINDS AND CLEARING SKIES EXPECTED. HIGHS BEHIND THE
FRONT WILL STILL REMAIN ABOVE NORMAL FOR MID JANUARY WITH READINGS
MAINLY IN THE UPPER 50S TO LOW 60S.

18z NAM Mon 00z 500mb


18z NAM Mon 00z 850mb


This post has been edited by StormChaserCK19: Jan 20 2012, 07:09 PM

[Mid Tn. Man]

[quote name='StormChaserCK19' date='Jan 20 2012, 06:07 PM' post='1506271']
Guys, this thread needs to get rolling! This looks like it could easily be the first SIGNIFICANT severe weather outbreak of the year. Check some of this stuff out...

It's looking like a April storm,The GOM is raging with warmth for this time of season

[Mid Tn. Man]

Slight risks the next few days, not sure if they all coincide or not, but current Day 3

[attachment=153128:day3otlk_0830.gif]

[attachment=153129:day3prob_0830.gif]

You're looking at the wrong storm Monger

This post has been edited by Mid Tn. Man: Jan 20 2012, 07:23 PM

[WeatherMonger]

You're looking at the wrong storm Monger

Gotcha, deleted it

[WeatherMonger]

You're looking at the wrong storm Monger

Actually, are you sure? The images StormChaser posted are for the system I posted the outlook for?

[Mid Tn. Man]

Actually, are you sure? The images StormChaser posted are for the system I posted the outlook for?

No it's this timeframe

[WeatherMonger]

Forbes had this to say back on the 6th of the month. With the 16-17th episode earlier and the current outlooks, it could have merit. A few other tidbits in there about 2012. Posted it in the long range spring thread a while back. Source

There has been a tendency for large tornado outbreaks during La Nina episodes during the January through April months.

The record numbers of tornadoes in each of those months occurred during La Nina conditions, including April 2011. Of the eleven largest and most impactful tornado outbreaks since 1950 in those months, six were during La Nina, 3 during El Nino, and 2 during neutral conditions. These statistics suggest, but don't guarantee, above-average tornado activity in January-April 2012. Historically this activity occurs mainly in the Gulf Coast (excluding the Florida Peninsula), Southeast, Mississippi Valley, and Tennessee Valley states.

[Mid Tn. Man]

Actually, are you sure? The images StormChaser posted are for the system I posted the outlook for?

I've been following this storm.I don't see no problem with 31B when he posted the thread,the GFS has just slowed the progression of the storm.Also to note the ECMWF is catching onto the GFS slow like.

[WeatherMonger]

I've been following this storm.I don't see no problem with 31B when he posted the thread,the GFS has just slowed the progression of the storm.Also to note the ECMWF is catching onto the GFS slow like.

No worries, thought maybe it had sped up a bit. The thread kind of died so didn't think much of it and then read the ILX AFD mentioning Sunday along with the SPC outlook. Looks like another thread is in order at some point

[Mid Tn. Man]

No worries, thought maybe it had sped up a bit. The thread kind of died so didn't think much of it and then read the ILX AFD mentioning Sunday along with the SPC outlook. Looks like another thread is in order at some point

LOL..as crazy as this winter is it's understandable.

[StormChaser4Life]

my buddy showed me this link about an analysis of the Super Tuesday on Feb 5-6 2008. the synoptic environment for this weekends storm looks eerily similar to that event. check it out and let me know what you think.

Synoptic Analysis of the "Super Tuesday Outbreak"

[StormChaserCK19]

HPC Map today for Mon 00z (Sunday Night)

[jdrenken]

Due to the models not having a good handle on this severe weather situation, and the SPC being void of confidence for the original dates, I have changed the dates to reflect the upcoming threat.

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CST SAT JAN 21 2012

VALID 221200Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN MO/AR/NRN LA EWD TO
THE W SLOPES OF THE APPALACHIANS...

...SYNOPSIS...
A LARGE UPPER TROUGH IS FORECAST TO SHIFT ACROSS THE CENTRAL U.S.
THIS PERIOD -- BECOMING MORE NEGATIVELY TILTED WITH TIME AS IT
CROSSES THE MS VALLEY LATE. MEANWHILE...A SECOND/WEAKER TROUGH IS
FORECAST TO MOVE ACROSS THE ERN PACIFIC -- REACHING THE W COAST BY
THE END OF THE PERIOD.

AT THE SURFACE...A COLD FRONT ASSOCIATED WITH THE UPPER SYSTEM
CROSSING THE CENTRAL U.S. WILL LIKEWISE MOVE ACROSS THE PLAINS
THROUGH THE DAY...AND THEN ACROSS THE MS/OH/TN VALLEYS THROUGH THE
END OF THE PERIOD. THIS FRONT WILL BE THE FOCUS FOR
CONVECTIVE/SEVERE POTENTIAL THIS PERIOD.

...MID AND LOWER MS/LOWER OH/TN VALLEYS INTO THE CENTRAL GULF COAST
REGION...
CLOSER AGREEMENT IS EVIDENT AMONG VARIOUS MODELS THIS FORECAST WITH
RESPECT TO PATTERN EVOLUTION...WITH TIMING AND LOCATION MORE
CONSISTENT. WITH A HIGHER THETA-E BOUNDARY LAYER SUPPRESSED ONLY TO
THE GULF COASTAL REGION BY THE PRIOR FRONTAL INTRUSION...NWD RETURN
OF MOISTURE AHEAD OF THIS NEXT/ADVANCING SYSTEM WILL SUPPORT MODEST
DESTABILIZATION OF THE WARM SECTOR. AS THE FRONT NEARS THE MID MS
VALLEY BY LATE AFTERNOON...STORM INITIATION IS EXPECTED -- WITH
SECONDARY DEVELOPMENT POSSIBLY ONGOING INVOF THE
REMNANT/BACKDOOR/DAMMING FRONT LIKELY TO BE LYING NW-SE ACROSS AL
AND INTO GA.

AS THE UPPER TROUGH BECOMES MORE NEGATIVELY TILTED WITH
TIME...STRONGER FLOW ALOFT SHOULD BEGIN TO SPREAD TO/ACROSS THE
SURFACE FRONTAL POSITION -- RESULTING IN INCREASINGLY FAVORABLE
SHEAR FOR ORGANIZED/ROTATING STORMS. LOCALLY DAMAGING WINDS WILL BE
POSSIBLE AS CONVECTION EVOLVES LINEARLY ALONG THE FRONT INTO THE
EVENING...WHILE A FEW SUPERCELLS WILL ALSO BE POSSIBLE ALONG WITH
ATTENDANT/ISOLATED TORNADO THREAT.

THREAT SHOULD CONTINUE THROUGH THE EVENING AS THE MAIN AREA OF
CONVECTION SHIFTS INTO THE MID SOUTH/CENTRAL GULF COAST REGION --
BEFORE SOME DECREASE IN INTENSITY OCCURS LATE IN THE PERIOD.

..GOSS.. 01/21/2012

[Sarah]

So how far north into Indiana are we talking for tornado threat? I had to stay the night in Daviess County tomorrow night (just north of Knox County aka Vincennes (pry 15 miles from it at most taking the old back country roads)

[jdrenken]

So how far north into Indiana are we talking for tornado threat? I had to stay the night in Daviess County tomorrow night (just north of Knox County aka Vincennes (pry 15 miles from it at most taking the old back country roads)

You could see some QLCS action making it's way into Central IN easily. Winds and hail will be the main threat.

The latest NAM is showing a nice squal line tomorrow night.