GFS picking up on the pattern change (SOME) but still lack of good blocking

 The GFS is catching on to a more colder possible stormy pattern to end December. Here in this image I have the GFS for Dec 24th (left) and Dec 26th (right) Now Not sure that this would being snow (if any) to NC east of the Mnts BUT has been showing up run to run.

NAO (seen here>, looks to go a bit Neg but still not a strong blocking signal at all. 
The AO also goes down some which would also help (SOME) this too is not enough to dump too much cold south 

If you scroll through this link here (which is the GFS ensemble members) start at hour 264 and so on, some do show a coastal storm off the SE US coast and some cold air in place (noted by the 540 red line over NC) http://www.meteo.psu.edu/~gadomski/ENSPRS_12z/ensloopmref.html

Recap of the April 9th VA/Carolinas severe weather event.

Well most of Saturday here in Central NC was cool and damp here at the surface, but yet we still had severe weather and storms how this is so, well for those who want to know Ill explain.
At 12z(8am local) we had a backdoor front push all the way to the Charlotte metro/upstate SC with most of central NC in a cool surface stable wedge.

Also the 12z SPC sounding showed a cool layer of air at the surface but just above that about850mb(5000ft) there was warm moist unstable air.

Along with some weak CAPE but lapse rates from 700mb to 500mb were 7c/km cooling with height also dry air was noted in a deep layer as well. Water Vapor imagery at 11:30am showed a short wave in the mid west with an MCV at the surface.

also note the SE ridge overhead. Fast forward a bit in time and by 4pm we started seeing severe storms show up over KY/VA and TN.

by 4:40pm we started to see supercells break out in W/SW NC with tornado warnings out.(heres base reflectivity and Velocity from GSP SC radar.

while still at the surface for central NC(all but Charlotte metro where dewpnts were in the 60s and temps in the 70s, this served as a focus for storms to train along.

but still storms were on going over the cool stable wedge airmass over central NC.

Where heres some answers as to why and how. First RUC analysis showed a 500mb short wave passing by helping to get lift going and the storms.

 

Sfc temps were in the 50s to upper 40s.

Along with the short wave and steep mid level lapse rates that produced a lot of lightning but also remember the 12z Greensboro sounding showed warm temps and good moisture at 850mb well heres a product called Theta-E all it is, is temp and dewpoint combined and the higher Theta-E the more unstable heres what we look at around 6/7pm.

Also Lifted index above the surface here very low and unstable

All and all this was a good severe weather event to learn something from and study for future setups hope you enjoyed.

More severe weather on the way.

After what seemed like an endless winter for people in the Mid West and Chicago, it looks like another severe weather event will come together for these areas starting on Sunday.
Lets take a look at the setup here and one thing I like to look at for convection is called Theta-E. Simply put this is a combination of the surface temperature and dewpoint. The higher the temp and dewpoint the higher the Theta-E and it is a good place to look for possible convection. Heres Sundays Theta-E map.

Next we need to look for CAPE, and in this case surface based CAPE.

Those two parameters alone can give you an idea if storms are possible but if a strong cap is in place or nothing to get lift going then your likely not to have much, but in this case we will have a lifting trigger and thats the cold front. Taking a look at the Helicity  values there will be some of that/Along with EHI values over 1 and that means a higher potential for tornadoes.

Also for supercells I look at the Sfc-1km shear and shear in this area of 30-40knts or greater means a higher likelihood of supercells. This is for overnight Sunday.

and 6hr precip overnight.

And with all this in mind NC also looks to get in on some severe weather by day3

Thats all for now Ill hae more later.

Monday night/Tuesday morning was a rough BUT exciting one.

A record breaking severe weather event unfolded from late Sunday evening April 3 to early Tuesday morning April 5 2011 with over 1200 reports of severe weather and a lot of tornadoes, one that was in Surry county NC. Also strong straight line winds raced across the Triad area with a few tornado warnings out also.
Severe reports.

Heres a few radar screen shots of the storms as they crossed into the Triad metro area.

Heres a close up of the Supercell that prompt the tornado warning in Davidson and Guilford counties.

Special thanks to Matthew East for the Gibson Ridge level 3 data.
Heres what the upper air sounding from Greensboro looked like 30 to 45mins before the storms hit at around 2:45am.

Just a prime severe weather sounding. The 00z sounding looked nothing like that the 6z above is from warm air advection and moisture advection.

The blocking pattern is back, like what we saw much of Dec/Jan this past winter.

Here on the water vapor image we can see a blocking pattern in place with an Omega block over Canada and a -NAO over Greenland.

Here is the Thursday evening upper air observation at 500mb.

And with an upper ridge in Canada and an upper low in eastern Canada, we here on the eastern US can expect cooler and wetter conditions. Highs will be droping ESE out of Canada and surface lows across the southern/central US untill this pattern breaks down sometime possibly next week.

One more warm day for central NC then a return to more early spring like weather/cooler weather.

Well a big pattern change is coming by Thursday and onward. With tomorrow the transition day as a cold front slides by the area bringing a chance for some thunderstorms possible. Now on to the patter set up for late March into early April at least. Lets start with todays setup below, as you can see a typical La Nina SE US ridge in place and a western US trough.

As we move into this weekend cooler/wetter weather looks to setup with the models showing a chilly/cold rain for central/western NC, noted by the GFS/ECMWF below.(for Tuesday morning)

Both models agree on a cold air damming setup east of the Mnts in NC, possible severe weather for the deep south and south eastern NC and SC.
The NAO is looking to go on the negative side for a while as seen below and the PNA positive.

So what does this mean, well after tomorrow (Wed) you can say goodbye to the beautiful 80 degree weather as cooler and possibly wetter weather to end March and start April, although I am keeping an eye on mid April for a return to warmer weather but Ill have more on April as the end of March draws closer.

Warmth on the way, then cooler weather by end of March.

Tomorrow and Friday/Saturday will be beautiful days across central NC with highs in the 70s and even 80s by Friday and Saturday. But by Sunday a backdoor cold front will slide in cooling us down for a day or so. Lets take a look at the set up for Fri/Saturday.
Friday's set up.

Nice upper lvl and surface ridge bringing in much above normal temperatures by close to 15-20 above, with a west/south west flow. Heres Saturdays high temps with some parts of the state getting into the low 80s.

But as such this time of year weather like this wont last long as cooler air will try and make a come back seen in this next image with a backdoor cold front coming in from the NE.

By Tuesday though this front will lift north again as a warm front and bring a surge of warm air back into NC.

And with that will come warmer temps as seen below.

Could be back in the mid to upper 70s here in central NC. Taking a look at the longer range though shows cooler/stormy weather may come back with the NAO going negative.

also severe weather could spike up again.

Warm up on the way next week, AFTER a chilly/cold rain early in the week.

Sorry for the lack of updates, Ive been busy with some other things. Now I wont touch on early next week as its looking like a two day deal or so Mon-Tuesday with chilly temps and some rain. I do want to talk about the big warmth coming later on next week. We'll start with day 5 Wed of next week and you can see the GFS Ens mean temp departures above normal.

Thats just the beginning as the warmth moves east heres day 7,

Friday is really looking like a warm day. Heres the ECMWF overview of Friday,

Just really warm stuff and HOT in the southern plains. Also the GFS agrees for the most part on this warmth coming east.

After all is said and done heres the week 2(not end of next week but after) departures.

And the EC/GFS 8-10day mean 500mb.

So some warm times ahead indeed.

Severe weather, area of most concern.

This is my main area of concern for tomorrows severe weather, for centers of popualtion.

Mian concerns, Strong Damaging winds, and tornadoes. hail aslo likely.

Outlook for March.

The month of March is almost upon us, and I think its time we look at a few monthly/seasonal forecast models to get a feel for how March may turn out. First here's the US Climate Forecast System (CFS). for the 500mb height anomaly.

A real La Nina pattern with a Bearing Sea ridge, and a Southern/SE US Ridge. Also note the trough in the west or just off the west coast. Here's the CFS 2meter 6ft temps (close to the surface) anomaly for March.

Big time warmth in the Southern Plains forecast by this model and I for one agree on that. Heres another model from NCC/BCC for the 30day mean 500mb anomaly from Feb 21 to March 22ed.

This model also keeps a mean ridge over the SE and a mean trough in the western US. But lets take a look at the probability map from the CFS for March in the temp department.

Good agreement with the southern plains staying warm and toasty, I think us here in the SE/Southern Mid Atlantic will stay warm for the most part but some cooler than avg times may be ahead in the month of March of us but likely not TOO cold or not lasting long either. Well what are the CPC boys saying, heres their real forecast map for March as of Feb 17th so likely this WILL be updated very soon so check the CPC out at this link http://www.cpc.ncep.noaa.gov/

As I said this is the forecast from the 17th of Feb, so soon they should update it and we may see that warmth expand more east to account for the deep south,(ie, GA,FL)more so BUT we'll see.