Go west young man....after work.

Well after a nice supercell today along the KS/NE border with a thousand chasers and there mom on....they should be alittle bit more spread out tomorrow given the wider area at risk for severe weather tomorrow as the trough continues its way east along with the amazing dynamics of this system. I have never seen this strong a jet in the month of april. 100kts at 500mb is just stupid.




Tomorrow has possibilities but with most setups around here there are the problems that could hamper the possibility of tornadic supercells on the cold front tomorrow in IA/MO and possibly IL. But there are also some good things like the shear storms are going to have to work with. I am kind of concerned with the moisture and low to mid 60 dew points are going to get up here in time, we shall see.

1. Ongoing convection as usual will have to be watched in the morning tomorrow and if it will move out of the area with enough time to get destabilization to occur. If there is alot of clouds then were not going to get enough instability for thunderstorms later on. The one plus about this is that there is the possibility of an OFB being left out.

2. Clearing- Tomorrow could be one of those days where the area is socked in clouds but one small area could see some sun for a few hours and that will be it, going to have to watch vis sat alot tomorrow to see what is going on.

3. Storm motions- These bad boys are going to be hauling tomorrow between 40-50kts which means staying on them is going to be very tough. going to have to sit east of where CI takes place and let them come to you if you want to have a shot.

4. Mode- There is quite a bit of forcing tomorrow and the question if and how long storms can remain discrete. If they can remain discrete they will go supercellular given the shear they are going to have to work with but if there is alot of forcing its going to be a honkin squall line with possible embedded supercells.

Here is an image taken off the 21z SREF showing tornado ingredients which combines different parameters which are needed for tornadoes.



The new SPC day 1 outlook just came out and showing the best risk west of the Miss. river in IA/MO which I had suspected. Its going to be interesting to see if things are linear or discrete. Everything should form into a line and move into northern IL before weakening overnight.



I will not be able to chase until after work at 4 or 4 30pm so im hoping the CF is a bit faster and the storms get here sooner then expected but Im not so confident in that happening.

If I was able to chase with more time and get to a target Id head to IA be somewhere in the Oskaloosa to Iowa City to Fairfield triangle.


Matt

easy choice for a title......HIGH RISK!!

Well SPC has pulled out the high risk with the 6z outlook (pretty large area for the first outlook of the day). For the past week it seems weather geeks and forecasters have been talking about the potential for severe weather outbreak in the south and now were in the morning of getting ready for a possible historic tornado outbreak in parts of AR/TN/LA/MS/AL.



Today was somewhat of a bust givn the 15% hatched tornado probs put out but tomorrow has alot higher confidence but there still are a few things that could play havoc on this setup that I have been looking at tonight.

1. The current convection in eastern TX working its way eastward could stabilize the warm sector and not allow for good enough heating later in the day limiting the risk of potential long track, violent tornadoes.

2. The track of the surface low and how quickly it deepens. A further north and west track would lessen the amount of forcing in the warm sector early on which would mean not as much junk convection to hamper heating.

3. The mid level dry punch, I think this is going to be the key player on what plays out tomorrow. If this can happen during the day tomorrow and allow surface temps to really warm up, then some high amounts of instability coupled with insane amounts of shear (both bulk shear and low level shear) is a deadly combination for cyclic supercells tomorrow in the warm sector producing alot of tornadoes, potentially violent ones at that.

forecast offices have been comparing past outbreaks in the late 90's to this setup and writing amazing AFD's that were just through the roof good on the potential this thing had and letting people know ahead of time. If things play out right tomorrow (or wrong for that matter) then we could be looking at a major tornado outbreak across the south.

here is the text from the new day 1 from SPC....I will probably be doing updated throughout the day with radar images and such as Im geeking out watching this potential tornado outbreak unfold.


...LOWER MS VALLEY...MID-SOUTH AND TN VALLEY REGIONS...
TSTMS SHOULD BE INCREASING IN COVERAGE/INTENSITY AROUND BEGINNING OF
PERIOD OVER E TX...LA AND ARKLATEX REGION. FOREGOING AIR MASS --
ALREADY MOISTENED/DESTABILIZED FAVORABLY BY PRIOR/OVERNIGHT THETAE
ADVECTION...WILL FURTHER DESTABILIZE AMIDST SFC DIABATIC HEATING.
AMOUNT OF HEATING IS SOMEWHAT IN QUESTION BECAUSE OF POTENTIAL FOR
CLOUD/ANVIL DEBRIS SPREADING DOWNSTREAM IN MID-UPPER LEVELS FROM
EARLY CONVECTION...PERHAPS INCLUDING TEMPORAL EXTENSION OF ACTIVITY
NOW OVER S TX. STILL...AWAY FROM EXISTING CONVECTION...EVERY
REASONABLE SCENARIO INDICATES THAT MLCINH GENERALLY WILL WEAKEN WITH
NWD EXTENT FROM GULF COAST...SUPPORTING EARLY AND RAPID DEVELOPMENT
AND INTENSIFICATION OF TSTMS FROM MID-MORNING THROUGH
MID-AFTERNOON...AND SUSTAINED THREAT SHIFTING EWD AND NEWD ACROSS
OUTLOOK AREA INTO EVENING/OVERNIGHT HOURS.

INTENSE VERTICAL WIND PROFILES WILL SPREAD ACROSS BROAD WARM/MOIST
SECTOR TODAY...MUCH OF WHICH ALREADY IS IN PLACE ACROSS MUCH OF
LA...MS AND COASTAL AL. THIS AIR MASS WILL SPREAD INLAND TOWARD TN
VALLEY AS CONVECTION/PRECIP NOW OVER TN/AL/GA SHIFTS NEWD. SFC DEW
POINTS WILL BE 70S INVOF GULF COAST...TRANSITIONING TO UPPER 60S AS
FAR N AS TN AND LOW-MID 60S TO OH VALLEY. WEAKENING LAPSE RATES
ALOFT AND BUOYANCY WITH NWD EXTENT...FROM TN VALLEY TO OH VALLEY AND
GREAT LAKES...RENDER PROGRESSIVELY MORE CONDITIONAL NATURE TO SVR
THREAT...THOUGH KINEMATIC PROFILES WILL BECOME FAVORABLE OVER VERY
LARGE AREA S OF GREAT LAKES BY EVENING/OVERNIGHT HOURS.

MULTIPLE CONVECTIVE EPISODES AND STORM MODES ARE EXPECTED IN THIS
SITUATION...AGGREGATE OF WHICH SHOULD YIELD DENSE CONCENTRATION OF
SVR EVENTS BY END OF PERIOD ACROSS MDT/HIGH CATEGORICAL RISK AREAS.
THOUGH DISCRETE/CYCLIC TORNADIC SUPERCELLS ARE MOST POTENTIALLY
DANGEROUS THREAT...ESPECIALLY OVER HIGH RISK AREA...CLUSTERED AND
QUASI-LINEAR CONVECTIVE ELEMENTS WITH EMBEDDED BOW/LEWP FORMATIONS
AND SUPERCELLS ALSO APPEAR PROBABLE. STRENGTHENING DEEP-LAYER WINDS
AND RELATED FAST STORM MOTIONS PORTEND LONG TRACKS FOR SUPERCELLS
AND FOR SOME OF THEIR TORNADOES...AS WELL AS FOR SWATHS OF DAMAGING
WIND WITH ANY BOW/LEWP FEATURES. THIS SUPPORTS RATHER ROBUST
PROBABILITIES FOR ALL SEVERE MODES.

PARAMETER SPACES IN FCST SOUNDINGS OVER HIGH RISK AREA -- SHIFTING
NEWD FROM LATE MORNING THROUGH AFTERNOON -- INCLUDE 50-60 KT LLJ
SUPPORTING VERY LARGE HODOGRAPHS WITH 0-1 AND 0-1 KM SRH 300-600
J/KG. ALSO EXPECT 50-60 KT EFFECTIVE SHEAR MAGNITUDES BENEATH
110-140 KT 250 MB JET MAX AND 60-90 KT 500 MB WINDS...POTENTIALLY
JUXTAPOSED WITH MLCAPE 1500-2500 J/KG.

getting my weather swerve on!

Well tornado season really got cranking this afternoon and evening in CO to KS down into the TX PH where 30 tornadoes have been reported so far and that number should continue to go up. Today was only the start of it and tomorrow and saturday look to be just as big if not bigger.

I cant chase tomorrow but if I was I would target Falls City, NE where the triple point/warm front is going to setup. The new NAM is showing H5 winds greater then 50kts out of the southwest nosing up into the area by late afternoon into the evening with southerly 850's and backed sfc winds up against the WF with nice convergence.

Storms will be ongoing in the morning but should clear out by the afternoon as the dry intrusion moves into the area and allows for destabilization to occur with CAPE values approaching 2500 j/kg by 0z with dew points nearing the mid 60s into the triple point and bumping up against the warm front with a nice theata-e axis.

Look for storms to fire during the afternoon hours between 20-22z with all modes of severe weather possible with any supercells that do form. could see some pretty large hail given the steep lapse rates. tornadoes will also be a pretty sizeable threat given the amount of shear that will be in place


Going to be an active day even though I wont be out and then we get to saturday....



Matt

What are the odds?? I will have to chase new orleans while I'm there haha

Im leaving to head down to New Orleans thursday morning and was just looking at the new 0z run of the GFS and started laughing when looking at the forecast for saturday afternoon down there and the severe weather potential it was showing. would be a nice consolation prize for not being able to chase the possible good setup the day before most likely in TX.

The system that will aid in the severe weather the day before saturday will continue moving eastward with an ULL centered western AR during the afternoon on saturday if this were the perfect prog, which its not, would have southwesterly flow near 40kts.



we also have nice low level winds at 850mb out of the SSW near 30-35kts pumping in some good moisture off the gulf with 850mb Td's nearing 15.



The moisture is for sure there with dew points in the mid 60's with backed surface winds up into the surface low further north across MO/AR.



here is a image showing the nice area of instability feeding up into the sfc low with CAPE values nearing 1500 j/kg.



and lastly, here is a forecast sounding for 18z on saturday showing the nice turning with height and descent hodograph.



the last time I believe new orleans was hit by a tornado was 2/12/07, which is when we had a pretty good snowstorm beginning that day.


Matt

And so it begins...

well I've had moderate to heavy snow falling since about 5:15pm and have 0.5" down so far. things will only get worse as the night goes on into the overnight hours when the heaviest snow is expected to fall.

there have already been reports of 5-12" in northern/northeast MO as the storm continues to ramp up. rates in northern MO/western IL have been impressive at 1-1.5"/hr this afternoon. rain has been reported in the southern suburbs and closer to the lake but has since gone over to snow at most places including ORD and MDW

here is an image taken off the 23z RUC, it has slowly been bumping up QPF for the overnight hours with some places picking up 0.3-0.5" QPF in 3 hours!



and here is a national radar loop of our storm

http://radar.weather.gov/Conus/full_loop.php

just in...

0646 PM SNOW OTTAWA 41.35N 88.84W
02/21/2010 M1.2 INCH LA SALLE IL TRAINED SPOTTER

SNOW FELL IN ONE HOUR AND IS THE TOTAL SO FAR. HEAVY
SNOWFALL CONTINUES.

will have another update around 10pm


Matt

storm update, 19z sunday

well the models have continued to trend drier with QPF and the have placed the heaviest snow band further to the southeast. snowfall amounts will be a bit less then thought yesterday but will still be a significatn snowfall for the area with totals ranging from 5-9" locally 10" possible in some areas. the dynamics and moisture with this system will aid in some impressive snowfall rates at or above 1"/hr at times in the heaviest snow bands.

the heaviest snow will fall from late this evening through the overnight hours and shut off pretty quickly during the mid morning hours as the low pressure slides off to to the east.

here is a image taken off the LSW WRF for early monday morning at 6z



LOT has upgraded parts of the area north of I-80 and west of dupage county to a winter storm warning starting at 9pm this evening and going through the day tomorrow.

It will be interesting to watch this system unfold tonight.


Matt

Storm Update

There have been no drastic changes but the 0z runs did nudge the main band a bit further south with less QPF but dont know if Im buying into that yet. waiting for the hi-res models to come in now. going to be intesting if the trend continues. the hi-res NMM holds its ground.

think chicagoland area from 1-88 on north will see around 6-10" with locally higher amounts taper down to 2-4" across the far southern counties due to having mixing problems. some pretty impressive returns going on right now down south in TX and OK with some thunderstorms. whats pretty cool is the WAA precip all the way in western IL with the ULL still back in the southwest.

http://radar.weather.gov/Conus/full_loop.php

here is an image from the SPC 4km WRF showing a very intense snow band from southeast IA to chicago



and this from the hi-res NMM



if things hold true then a snow day for parts of the area could be a real possibility given the heaviest snow will be falling during the overnight hours into the morning.

and lastly here is the text from the winter storm watch from the chicago office...

WINTER STORM WATCH REMAINS IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON...A WINTER STORM WATCH REMAINS IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON.

* TIMING...SNOW IS EXPECTED TO DEVELOP ACROSS NORTHERN ILLINOIS BY SUNDAY EVENING. AREAS NORTH OF THE INTERSTATE 80 CORRIDOR WILL RECEIVE MAINLY SNOW FROM THIS SYSTEM. THE SNOW MAY BECOME HEAVY SUNDAY NIGHT INTO EARLY MONDAY MORNING...WITH ACCUMULATION RATES OF AN INCH PER HOUR EXPECTED.

* ACCUMULATIONS...TOTAL ACCUMULATIONS OF 8 TO 12 INCHES ARELIKELY...GENERALLY ALONG AND NORTH OF INTERSTATE 88...TAPERING TO AROUND 6 INCHES TO THE SOUTH WHERE PRECIPITATION MAY MIX WITH SLEET AT TIMES. THE SNOW SHOULD BEGIN TO DIMINISH FROM THE WEST AROUND MID DAY MONDAY.


Matt