Absolute Vorticity

tpweather wrote: ↑Mon Feb 27, 2023 8:06 am Good Morning Les. Euro went towards what it had on Saturday for the track. My biggest problem is finding enough cold air to work into the system to bring us snow no matter what the track. No front end snows of course and since the system is progressive getting enough cold air on the back side before precip is over could be tough. Rainfall totals look nice especially for a system that is progressive. Kind of systems you get those quick flash floods because rainfall totals can be heavy for a 6 hour period.

Looking further out and most show the nao and ao going negative so that is a good sign and hopefully just getting the pna to get neutral for a spell will help. Still rooting for that one big snow and then spring can take over.

tron777 wrote: ↑Tue Feb 28, 2023 7:40 am Good morning all! We'll see the 70s to begin March on Wed. Showers t-storms late Wed into Wed evening. A break Thurs, then our heavy rain and wind maker Thurs night and Fri. 1-2"+ of rain for most folks. No real shot of cold air behind that system either. The changes to the pattern should come as we approach mid March. Sometime after the 10th due to better MJO Phase, -EPO -NAO starts to decay. We'll see guys. The way this winter has gone nothing has been easy accept to forecast warmth.

tron777 wrote: ↑Tue Feb 28, 2023 8:44 am Only long range thought to add is that all Ensembles now as well as the Euro Weeklies are showing a colder pattern from 3/10 onwards and it lasts for 2-3 weeks. This is not a forecast just posting what the data is showing. The MJO is strongly in Phase 8, west based -NAO begins to decay. But we gain the Pacific. If the -WPO / -EPO combo is real, it's going to get cold. Models are showing blocking across the top with a coast to coast trough, ala below normal temps for most of the country. With the active STJ and these potent lows we keep seeing, if the Pacific teleconnections are correct, cold will get injected into the pattern.

Bgoney wrote: ↑Tue Feb 28, 2023 9:32 am

tron777 wrote: ↑Tue Feb 28, 2023 8:44 am Only long range thought to add is that all Ensembles now as well as the Euro Weeklies are showing a colder pattern from 3/10 onwards and it lasts for 2-3 weeks. This is not a forecast just posting what the data is showing. The MJO is strongly in Phase 8, west based -NAO begins to decay. But we gain the Pacific. If the -WPO / -EPO combo is real, it's going to get cold. Models are showing blocking across the top with a coast to coast trough, ala below normal temps for most of the country. With the active STJ and these potent lows we keep seeing, if the Pacific teleconnections are correct, cold will get injected into the pattern.

Normals for mid month+- are around 51 and 32 and it looks like atm models are showing about 6-10+-degrees below norms, so a lot of low to mid 40s for highs and low to mid 20s for lows

tpweather wrote: ↑Tue Feb 28, 2023 9:42 am Hoping the colder air does make into much of the country and this will hopefully give the south central states a better shot at rainfall. The west is getting plenty of rain and snow this winter season but in the middle of the country not so much. Heat ridges build more quickly where the ground is dry and this is bad news for Texas and Oklahoma in May unless we can get some decent rains over the next 45 days. Feel if the heat does arrive early there we could see an early heat wave for us in late May or early June and those tend to last longer as we get into mid-summer rainfall is more isolated at best. Still to early and lets see how the pattern plays out but though I would love to see some snow here I rather have the decent rains down there looking long term.

tpweather wrote: ↑Tue Feb 28, 2023 9:42 am Hoping the colder air does make into much of the country and this will hopefully give the south central states a better shot at rainfall. The west is getting plenty of rain and snow this winter season but in the middle of the country not so much. Heat ridges build more quickly where the ground is dry and this is bad news for Texas and Oklahoma in May unless we can get some decent rains over the next 45 days. Feel if the heat does arrive early there we could see an early heat wave for us in late May or early June and those tend to last longer as we get into mid-summer rainfall is more isolated at best. Still to early and lets see how the pattern plays out but though I would love to see some snow here I rather have the decent rains down there looking long term.

Bgoney wrote: ↑Tue Feb 28, 2023 9:59 am

tpweather wrote: ↑Tue Feb 28, 2023 9:42 am Hoping the colder air does make into much of the country and this will hopefully give the south central states a better shot at rainfall. The west is getting plenty of rain and snow this winter season but in the middle of the country not so much. Heat ridges build more quickly where the ground is dry and this is bad news for Texas and Oklahoma in May unless we can get some decent rains over the next 45 days. Feel if the heat does arrive early there we could see an early heat wave for us in late May or early June and those tend to last longer as we get into mid-summer rainfall is more isolated at best. Still to early and lets see how the pattern plays out but though I would love to see some snow here I rather have the decent rains down there looking long term.

I agree Tim , that area of Texas/Oklahoma has had dust storm after dust storm as they along with everyone else have had non stop high winds. Not sure either if and when the nee pattern sets up if their luck changes . The new pattern and jet will be zonal west to east but further south than usual of course, so they could get in on more moisture. An area that I'm more confident in getting more moisture is the south and SE as they'll be near that jet streak and baroclinic zone in mid March and beyond

tron777 wrote: ↑Tue Feb 28, 2023 10:56 am 12Z GFS has a 977 MB low over STL Fri morning with heavy rain in our hoods as the warm front works into the ILN CWA and lifts northward. I would already plan on another wind advisory being issued for this event. 2" of rain or more is not out of the question and the guidance hasn't changed much in recent days. I think I mentioned 1-2"+ for everyone and that's a good call this far out but may need to up the bottom part of that range in days to come provided that the strength of the low is real. Not sure how long we'll be in the warm sector. We were in it much longer then expected and got the needed CAPE thanks to the sun for yesterdays event. We'll have to see how long we get for into the warm sector for Friday. Do we see a similar dry slot for the boundary layer to mix down and get some CAPE or will it mainly be a cloudy, rainy, and windy day with little in the way of t-storms? We shall see! SPC currently targeting the TN Valley and points south on their Day 4 Outlook.