Forecast 3/8-3/10 Central US

I hate to get into details of model data that will likely change, but next week has captured my full attention.

With respect to timing, moisture issues, etc.. If only part of what I see in the GFS forecast (12z 3/2 run) comes close, we're all in for a real treat next Thursday to even Saturday. Very strong 500 mb trough blasing through the southern plains causing a rapid surface low to develope.

Get your camera equipment charged! I think this is our first opportunity of the season.

At least I hope so.

Tim
 
I've been watching this also. If the GFS verifies, it'll be quite an active period next week and beyond. I'm more interested in the second storm shown on the GFS for east of the Mississippi...
 
I posted this a week ago before the last disappointment
The models have been pretty consistently trying to pull short-wave energy into the southwest and then out into the southern plains for the last few months. Instead they've been less progressive and more absorbed into a single jet, rather than splitting the flow.

This seems to still be the case, as the models are ever-more pessimistic about any significant impulse making it very far in from the coast. Sad More rainless days for us and drought for the southern plains. It wouldn't be too bad a picture storm-wise for the spring, but until the Gulf opens up more it's gotta suck.

I think this pattern seems to be characteristic of how the GFS has been handling the west coast short-waves lately, so I'm not very optimistic about this next one. I hope I'm wrong because it would not only mean precip in the areas that need it badly, but a good chance of some early season supercell races :wink: for the friends on the southern plains.
 
I'd like the low to trend farther west to pull the warm bubble up into Southern WI to get me an early season treat. I need warm weather bad.
 
Looks like a good shortwave moving into the southern plains March 8ish and into the mid miss. valley on the 9th. The large longwave system moving in behind it looks equally impressive. Large pocket of 10+ 850mb dews from 3/2 12Z GFS forecasted for most of AR and southern MO out ahead of the intitial s/w as it moves out of the plains and into the trees. 50+kt ssw LLJ, 500 mb sw streak well over 100 kts, and a rapidly deeping surface low to the west all spell show time, at least for now. It is March, and tornado season has been known to open with a bang during week 2. Who knows? And La Nina is in, that usually means something significant somewhere (pick a # on where though). If the storm can kinda meander around the four corners region long enough to pull up deep gulf moisture, it could be a heckuva period.
 
March is primetime for strong/violent tornadoes for Arkansas, Mississippi, and Alabama. Several of these systems at mid/end of next week look like they will have that significant tornado threat...the Thursday 9th storm especially. I have not seen anything that powerful and negatively tilted in quite a while. I am getting things ready for the chase next week. Things have been too consistent on all the long rangers to expect any radical pattern changes...no matter how shaky the GFS performance has been. Timing will be the big key and this will be watched closely by all those that are involved with severe storms from SPC to the chasers and spotters. It looks pretty scary.
 
I am optimistic as well. Analogs here from SPC have been remarkably consistent with relatively large area of +15% cumulative severe probabilities over the Central US in this timeframe. The GFS continues to plug along with its idea of a more southwesterly flow and will put my area right into the storm track. Looks to FINALLY be enough moisture surge north to make this interesting. Right now I have a guarded interest but it is growing every model run. Considering adding some thunder to the extended in my forecast tonight...
 
:roll: :lol:

The models all have quite ample time to flip and flop back and forth at will over the next 7 days. Any speculation is really just wishcasting right now. LAST WEEK they were showing a "monster negative tilt trough" for this weekend. Uhuh....riiight.

I may seriously begin to consider what the models are showing for next week when next week arrives.

Meanwhile - it's time to drink some wine over the weekend....

Karen
 
Ah Karen ever the pessimist. :wink: But, who can blame you after your 2005 season?

I'm at least glad to see I'm not the only one impressed by the GFS output for mid-late next week- it increases my confidence in my ability to correctly interpret model output, which I wasn't sure of for quite awhile. At least I can make SOME sense out of all those lines and barbs and figures. :D
 
I'm usually not one to wishcast this far out, but the GFS 144hr 500 mb fcst looks very similar to the 500 mb analysis the morning of 13 March, 1990
(that was the day of the Hesston, KS F5 for those too young to remember).

Check out the synopsis for the Hesston event via Doswell's paper at
http://rammb.cira.colostate.edu/resources/...ocs/Hesston.pdf

Also, last nights ensemble spagetti chart for 168hr (Wed evening, 8 March) is encouraging - not very much spread:

http://www.cdc.noaa.gov/map/images/ens/spa...ag_f168_us.html

Certainly someting to keep an eye on.
 
The one thing that stands out to me about the GFS "forecast" (wishcast right now IMO, but that's beside the point) is the shape of that trough out west... I mean, I think when we see deep troughs like the one forecast, the height gradient is a little less intense as the gradient spreads out over a larger area... In this case, like 3-13-90, the heights are very low very far south, with nearly uniform 500mb heights over a large area in the heart of the trough, leading to a very intense mid-level height gradient (thus the 115kt+ 500mb winds on the GFS). The diffluent nature of the flow as the nose of the jet streak rounds the base of the trough and pokes into the Plains, along with the mid-upper level progs as a whole, certainly screams "synoptically-evident severe weather outbreak" to me. Of course, we're still PLENTY of time away from this potential event, so I'm not getting too pumped about it yet. We have a tough time with 3-day forecasts, much less 7-10 day forecasts LOL.

I wouldn't mind see the 3200 j/kg SBCAPE and 405 m2/s2 0-3km SRH that characterized the environment near Hesston per the Doswell paper linked above, however.
 
It was pointed out to me that last night's 0z upper air charts included data from around and inside the system off the west coast from dropsondes released as part of some research project. The charts from 0z included upper air data we normally observe over land, and were spatially more dense than current CONUS coverage. I was told this data was almost certainly ingested into 0z model runs.

Whether or not this means that the solutions are more accurate as a result of the dramatically improved sampling, I don't know.
 
Comparing the 18Z just coming in with the 12Z, MOTS as with previous systems to my eye I'm afraid. The system is a bit more open and is starting to scream, "squall line!" for eastern TX, LA, and AK. The elements seem less well synched for you Plains guys with discouraging factors like RFJ subsidence. The best chance on the 9th may be along warm front convergence that might be in the general area of Cairo, IL. FWIW (not much)!
 
I found a couple of links to GFS CAPE Forecast Maps:
Always Check Time and Date of Each Product and The Time of the Run
http://weather.cod.edu/forecast/GFS/
http://wxmaps.org/pix/avnmr.pw.html

Source: COLA and College of Du Page

Also a paid-site Wright-Weather has GFS CAPE maps
http://www.wright-weather.com/

Amos mentions about dropsondes:
OVERVIEW OF THE 2006 WINTER STORM RECONNAISSANCE PROGRAM
http://www.emc.ncep.noaa.gov/gmb/targobs/t...06overview.html
http://www.emc.ncep.noaa.gov/gmb/targobs/t...et/wsr2006.html

Source: NCEP

Mike
 
I expect that this wintery pattern will finally change by next week. The model runs have been trying to dig a huge trough in the SW for some time now. These first two were weaker than I thought they would be, but they did have hail and tornado warnings in CA the other day. These next few coming on shore next week definitely will have more energy. If the Gulf of Mexico opens up for biz it will be on!

My prediction for southern WI is another snowstorm. It will go south, I just know it! Looks good for the Southern Plains and Lower Missouri Valley though.
 
I will be glad if this setup comes to fruition if only for the fact that it will be the test of whether or not this dry winter will really affect chase season like it has been speculated. Will the dry ground have adverse effects on boundary layer dewpoint depressions? Will the tornadoes be giant, amorphous dust bombs with no funnel visible?

IMO I think we'll be just fine for spring 2006, but I'd like to see one good event to be sure.
 
NOUS42 KWNO 030309
ADMNFD
SPECIAL NCEP DISCUSSION
CENTRAL OPERATIONS/NCEP/NWS/WASHINGTON DC
0250 UTC THU MAR 03 2006

030250Z...00Z GFS IS OFF AND RUNNING ON TIME..

16 DROPSONDES FROM THE G-IV WERE AVAILABLE
FOR 00Z GFS INGEST..

...

GFS RAOB REPORT..
SLE/72694 - MISSED THE NAM...IN FOR THE GFS
BRW/70026 - PURGED HGTS AND TEMPS...BAD REPORT

SHIREY/SDM/NCO/NCEP

Whoever said NOAA jet obs were being ingested is correct. They are sampling the Pacific Coast trough. Tonight's 00Z NAM had some data delay problems so they only ran auto qc and therefore I noticed some changes but the GFS seems reasonably consistent.

Generally all long range models agree a significant shortwave will eject out into the SP Wednesday and then follow the thermal ribbon up into the Great Lakes Thursday. Most agree on a sub 994 mb low Wednesday around 12Z in the "panhandles" area...so I would say those in the Plains and Miss/Ohio Rvr Vlys stay tuned!
 
Seems like everyone is picking up on this pattern change that is being advertised (unlike the last couple of times it did this in the extended). Here's a quote from the CPC:

Severe thunderstorms, along with tornadoes, damaging winds, and heavy downpours are possible on March 8-9 from Texas to Illinois.
 
This morning's EC and GFS runs appear to be in good concert with the position of the 500 shortwave at 0Z. Nothing like the Armageddon run of yesterday with a massive vorticity maximum overspreading the entire southern plains, but still strong enough to induce good destabilization and vertical motion from the predicted 500 mb height falls in the 100-150 meter range. There appears to only be modest boundary layer moisture at this point and the dryline appears rather diffuse by early evening. I expect an event similar to March 21 of last year with a vigorous synoptic system and a rapid eastward progression of the dryline, likely touching off convection when it interacts with deeper moisture in Eastern Oklahoma/North Texas.

HPC even mentions the possibility of severe weather in the MRFD:
...PLAINS/MS VLY...
THIS WILL OPEN UP THE
GULF OF MEXICO AND SET THE STAGE FOR A STRONG EARLY SPRING
CONVECTIVE OUTBREAK WED-THU OVER MID AND LOWER PORTIONS OF THE ERN
PLAINS/MS VLY.
 
Thursday looking pretty scary for EC/SE Missouri...C/S Illinois southward into Mississippi. Looks like St.Louis may get hammered if 12z GFS is locking in. Still lots of time (and dreaming) to do. Plan on chasing thats one thing for certain.
 
I might have to miss a class or two if this thing starts any farther east. If this thing looks like the outbreak many are hinting at, I will definitely get myself over there.
 
Much like the time of the convention, I have a Math exam on the 10th, except there's no getting out of this one so the chances of making it out for this event look pretty slim. It's just the beginning of the season though so I'm not too disappointed and it will be nice to see the reports if this even happens.
 
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