Big bomb/Witch of November the week of Thanksgiving?

[Bill Tabor]

I should mention that my previous comments were about the areas that I would chase Tx, Ok, and maybe Ks. Further east of there I really didn't analyze. So maybe they still have a shot at torns? I'd have to look. I will note that the sfc low and mid level cyclone are now syncing up more in the latest runs and have pulled further west and maybe a bit south than previous. If moisture is in this area on Tuesday - look out!

 

[mikegeukes]

Interesting to watch the models over the past few days, how the solutions change over time, I remember the GFS for awhile was progging the low with a pressure of 981 mb into the Great Lakes region, latest 18z GFS has the low much further south along the Indiana-Ohio border with a pressure of 999 mb. Note: The area I been focusing on is Michigan.

Mike

 

[Robert Dewey]

Originally posted by mikegeukes
Interesting to watch the models over the past few days, how the solutions change over time, I remember the GFS for awhile was progging the low with a pressure of 981 mb into the Great Lakes region, latest 18z GFS has the low much further south along the Indiana-Ohio border with a pressure of 999 mb. Note: The area I been focusing on is Michigan.

Mike

Same here... Looks like this bomb busted...

 

[Andy Wehrle]

I dunno...I've never heard an NWS office talk up a severe weather event this hard three or four days out before:

...SIGNIFICANT CONVECTIVE EVENT EXPECTED TUESDAY THROUGH TUESDAY NIGHT...

.SYNOPSIS...THE POTENTIAL REMAINS STRONG FOR A HIGH END SEVERE
CONVECTIVE EVENT BEGINNING TUESDAY AND LASTING INTO TUESDAY NIGHT. MODEL TO MODEL AND RUN TO RUN CONSISTENCY WITH THE DEVELOPMENT AND TRACK OF THE MAIN CORE OF THIS SYSTEM IS UNPRECEDENTED.

FOR NEARLY 5 DAYS...THE GFS...CANADIAN...AND ECMWF HAVE BEEN IN
ALMOST LOCKSTEP AGREEMENT. THE SHORTER RANGE MODELS...ETA AND UKMENT...ARE ALSO IN AGREEMENT. OTHER MODELS...NOGAPS AND DGEX ALSO HAVE SHOWN STRONG AGREEMENT. THE ENSEMBLES ARE ALSO IN STRONG AGREEMENT. THE ONLY SLIGHT DIFFERENCE IS THAT THE MODELS HAVE SLOWED THE SYSTEM DOWN SLIGHTLY...BY A FEW HOURS AND THAT THE SURFACE LOW IS JUST A LITTLE BIT FURTHER SOUTH. NEVER-THE-LESS THE MODEL AGREEMENT IS IMPRESSIVE.

THE ANTICIPATED ATMOSPHERIC SYNOPTIC AND MESOSCALE PATTERNS MIMIC THE PATTERN THAT WAS OBSERVED ON NOVEMBER 21, 1992. THE ONLY SIGNIFICANT DIFFERENCE IN THE EXPECTED PATTERN VERSUS THE PATTERN BACK IN 1992 IS THAT THE EXPECTED PATTERN SHOWS BETTER ORGANIZATION IN THE LOWER LEVELS...MORE MOISTURE AND THE EXPECTED UPPER LEVEL JET IS COUPLED OVER THE ARK-LA-MISS. BY THE WAY...THE EVENT OF NOVEMBER 21, 1992 PRODUCED 15 TORNADOES...INCLUDING 2 F4'S...1 F3...AND 6 F2'S OVER THE JACKSON COUNTY WARNING AREA ALONE.

NEEDLESS TO SAY...THERE WILL BE A CONFERENCE CALL SCHEDULED WITH LOCAL EMERGENCY MANAGEMENT TOMORROW.

Does anyone know anything about the Jackson NWS? Are they often overly alarmist?

 

[Robert Dewey]

Originally posted by Andy Wehrle
I dunno...I've never heard an NWS office talk up a severe weather event this hard three or four days out before:

...SIGNIFICANT CONVECTIVE EVENT EXPECTED TUESDAY THROUGH TUESDAY NIGHT...

.SYNOPSIS...THE POTENTIAL REMAINS STRONG FOR A HIGH END SEVERE
CONVECTIVE EVENT BEGINNING TUESDAY AND LASTING INTO TUESDAY NIGHT. MODEL TO MODEL AND RUN TO RUN CONSISTENCY WITH THE DEVELOPMENT AND TRACK OF THE MAIN CORE OF THIS SYSTEM IS UNPRECEDENTED.

FOR NEARLY 5 DAYS...THE GFS...CANADIAN...AND ECMWF HAVE BEEN IN
ALMOST LOCKSTEP AGREEMENT. THE SHORTER RANGE MODELS...ETA AND UKMENT...ARE ALSO IN AGREEMENT. OTHER MODELS...NOGAPS AND DGEX ALSO HAVE SHOWN STRONG AGREEMENT. THE ENSEMBLES ARE ALSO IN STRONG AGREEMENT. THE ONLY SLIGHT DIFFERENCE IS THAT THE MODELS HAVE SLOWED THE SYSTEM DOWN SLIGHTLY...BY A FEW HOURS AND THAT THE SURFACE LOW IS JUST A LITTLE BIT FURTHER SOUTH. NEVER-THE-LESS THE MODEL AGREEMENT IS IMPRESSIVE.

THE ANTICIPATED ATMOSPHERIC SYNOPTIC AND MESOSCALE PATTERNS MIMIC THE PATTERN THAT WAS OBSERVED ON NOVEMBER 21, 1992. THE ONLY SIGNIFICANT DIFFERENCE IN THE EXPECTED PATTERN VERSUS THE PATTERN BACK IN 1992 IS THAT THE EXPECTED PATTERN SHOWS BETTER ORGANIZATION IN THE LOWER LEVELS...MORE MOISTURE AND THE EXPECTED UPPER LEVEL JET IS COUPLED OVER THE ARK-LA-MISS. BY THE WAY...THE EVENT OF NOVEMBER 21, 1992 PRODUCED 15 TORNADOES...INCLUDING 2 F4'S...1 F3...AND 6 F2'S OVER THE JACKSON COUNTY WARNING AREA ALONE.

NEEDLESS TO SAY...THERE WILL BE A CONFERENCE CALL SCHEDULED WITH LOCAL EMERGENCY MANAGEMENT TOMORROW.

Does anyone know anything about the Jackson NWS? Are they often overly alarmist?

I don't know, but that's some very strong wording!

 

[Andy Wehrle]

Strange. That AFD was written at 2:30 PM CST today, well after 18Z. Filling the cyclone from a 981 MB bomb to 999 MB doesn't seem like very good model agreement to me...

 

[Joel Wright]

Well apparently this storm turned out to be a joke. This just shows how much the models SUCK beyond 60hrs. This is largly due to the horrible network of upper air data over the Pacific. This problem will never be resolved until the network is somehow improved. Unfortunately I don't see how that can happen...... :?

 

[Robert Dewey]

Originally posted by Joel Wright
Well apparently this storm turned out to be a joke. This just shows how much the models SUCK beyond 60hrs. This is largly due to the horrible network of upper air data over the Pacific. This problem will never be resolved until the network is somehow improved. Unfortunately I don't see how that can happen...... :?

What are you talking about?! Just take a look at the 180 HR GFS for this 00Z RUN, LOL :lol: :lol:

 

[Bill Schintler]

Winter storm forecast

Winter weather forecast for Tuesday noon CST (18Z, 11/23/04) through Wednesday noon CST (18Z, 11/24/04).

Snowfall forecast:
The snowfall will fall over a narrow path during this storm.
1) 4â€-7†snowfall along and within 10mi either side of a Cameron, MO to Champaign, IL line.
2) 1â€-3†snowfall within 30 mi of the same line.
3) Trace to 1†snowfall along and south of a Shenandoah, IA to Osceola, IA to Washington, IA to Le Salle, IL line; and along and north of a Kanasas City to Moberly, MO to Springfield, IL to Decatur, IL line.

Discussion:
The surface low will track roughly along I-44. All recent model runs (12Z and 00Z today) have been in reasonable agreement of the surface low and the 500mb close low (500mb low later opening up into an open wave through 00Z Thursday as it lifts off towards the great lakes) position and timing. There are typically two primary precipitation regimes for such winter storms: First, the WAA isentropic up glide region – for this storm, temperatures will be far too warm for significant winter precipitation and no further discussion will be given to this mode. The second precipitation area is associated with dynamic cooling with the deformation zone. Sufficient cooling will take place throughout the column and in association with this is impressive 850mb to 700mb frontogenesis along and 50 mi N of I-44 in MO between 12Z, Wed and 0Z Thursday. Given 0.5†to 0.75†QPF between 0Z, Wed and 0Z, Thur. along the Cameron, MO to Champaign, IL line; and using an 8 to 1 snow to rain ratio (surface temps 30-35F, 850mb temps falling from +2C to –5C over that period, and 700mb temps falling from –3C to –13C over the same period), expect a narrow path of 4â€-7†snowfall. Snowfall will fall off rapidly to the south as a result of warmer temperatures at the surface and aloft, and also to the north as a result of dry air working in from the north (surface to 700mb).

bill

 

[Andrew Pritchard]

Re: Winter storm forecast

Originally posted by Bill Schintler
Winter weather forecast for Tuesday noon CST (18Z, 11/23/04) through Wednesday noon CST (18Z, 11/24/04).

Snowfall forecast:
The snowfall will fall over a narrow path during this storm.
1) 4â€￾-7â€￾ snowfall along and within 10mi either side of a Cameron, MO to Champaign, IL line.
2) 1â€￾-3â€￾ snowfall within 30 mi of the same line.
3) Trace to 1â€￾ snowfall along and south of a Shenandoah, IA to Osceola, IA to Washington, IA to Le Salle, IL line; and along and north of a Kanasas City to Moberly, MO to Springfield, IL to Decatur, IL line.

bill

I would be careful forecasting that much snow accumulation. I live in Champaign, IL...where you have 4-7 inches forecast...but temperatures over the last week or two have been in the 60s, and even in the mid 70s for a day or two...so the ground is still very warm. I doubt we'll see much snow anyway, looks primarily like a heavy rain event, with snow flurries on the back side.

 

[Andrew Geil]

I must concur with Andrew (not just cuz he has a good name). I don't think there will be much accumulation here, if any. Odds are, we're going to get rained on like nothing else, followed by a evening of cold drizzle. Just how I like to spend my nights at work, in sleet!

 

[Laura Duchesne]

From what I gather, when it arrives here in the Great Lakes region, it will start of as rain, and then change into snow/flurries as it begins to head east as the cold air moves in. If the entire low brought just snow, then I could foresee some good accumulation, but the fact that rain is a great possibility, I doubt it.

 

[Andy Wehrle]

Well, this may not be a big snowmaker for the Upper Midwest (something I'm fine with since I have to travel Wednesday), there could be another one coming. Time to start wishcasting, courtesty of NWSFO-GRB:

MED RANGE MODELS STRUGGLING WITH THE TIMING AND TRACK OF SIG STORM SYSTEM LATE IN THE WEEKEND/EARLY NEXT WK. NOT NEARLY ENOUGH CONSISTENCY TO GO WITH MORE THAN A CHC OF -SN. CONFINED THAT TO MON SINCE TREND SEEMED TO BE TOWARD SLOWER TIMING. THE AMPLIFIED LARGE SCALE PATTERN WOULD APPEAR FAVORABLE TO SUPPORT A SIG STORM SYSTEM IN THE CENTRAL UNITED STATES. THERE WOULD ALSO APPEAR TO BE ENOUGH COLD AIR TO SUPPORT SNOW NW OF THE STORM TRACK. WL NEED TO WAIT AND SEE HOW PATTERN STARTS TO EVOLVE THE NEXT COUPLE DAYS BEFORE CONFIDENCE INCREASES ENOUGH TO GO BEYOND CARRYING A CHC IN THE FCST.

Lovely. I will again have to travel on Sunday to get back to UWGB for Monday classes. :roll:

 

[Bill Tabor]

Well, appears to me that the Witch is still alive and the bomb fuse didn't go out afterall. Instead this thing is pulling further west and south, and now obviously Tx is the target. Tough part is...flooding is everywhere. Be very careful of road conditions if you chase this.
:blob6:

 

[Bill Schintler]

Re: Winter storm forecast

The timing of the rain/snow change over in IL is very difficult, which of course will have a huge affect on how much snow falls there. Otherwise, based on what I've seen today, I think this forecast is on target except I would move the western extent of the heavy snow band in western MO to the south 50-70 mi. bill

Originally posted by APritchard+--><div class='quotetop'>QUOTE(APritchard)</div>

<!--QuoteBegin-Bill Schintler

Winter weather forecast for Tuesday noon CST (18Z, 11/23/04) through Wednesday noon CST (18Z, 11/24/04).

Snowfall forecast:
The snowfall will fall over a narrow path during this storm.
1) 4â€￾-7â€￾ snowfall along and within 10mi either side of a Cameron, MO to Champaign, IL line.
2) 1â€￾-3â€￾ snowfall within 30 mi of the same line.
3) Trace to 1â€￾ snowfall along and south of a Shenandoah, IA to Osceola, IA to Washington, IA to Le Salle, IL line; and along and north of a Kanasas City to Moberly, MO to Springfield, IL to Decatur, IL line.

bill

I would be careful forecasting that much snow accumulation. I live in Champaign, IL...where you have 4-7 inches forecast...but temperatures over the last week or two have been in the 60s, and even in the mid 70s for a day or two...so the ground is still very warm. I doubt we'll see much snow anyway, looks primarily like a heavy rain event, with snow flurries on the back side.[/b]