Update----disappointing

[bfez1]

UPDATE: Just getting the latest GFS in. It's looking like a rain event now, I'm afraid. But who knows, something could change again.

Severe weather still looks on track for tomorrow, with damaging winds and isolated tornadoes. Beyond that, some huge changes in the models this morning which may not be good for snow lovers, or cold lovers for that matter.

The Euro started showing this last night, the GFS just this morning. But some subtle differences in upper air features are leading to big changes in the weather NOLA will get.

Specifically, both the GFS and the Euro are now showing a strong vorticity maxima (spin) moving out of Canada and across Utah into Arizona. This carves out a cut-off low (on the Euro) in the upper levels over old Mexico which does not phase with the main trough lifting through the Midwest. What this means in a nutshell is that the northern and southern branches of the jet do not phase - with the southern piece of energy hanging back behind the big trough moving across the northern stream. The end result of this is the following:

1.) Less Cold Air Intrusion (perhaps even no freeze southshore Saturday morning)
2.) Rain instead of snow, although it could mix with sleet or snow, especially north of the lake.
3.) Rain chances sticking around through the weekend as the aforementioned upper feature moves through slowly.

We will not be making any wholesale changes to the extended forecast right now, but may make changes later as we look at the data more. If I were to change anything, I would bring up highs quite a bit overall, and lows as well, along with keeping the precip mostly rain for Friday, even though it could start as a little mix. For now I am not going to do that because we need to see some more data first, and I will be awaiting what the new GFS run says here in the next couple hours.

For those wanting snow and cold, we need the southern feature to phase with the northern trough. If it slows or gets held up, all bets are off.

More updates as info becomes available....and of course, all is subject to change.

John


John Gumm
Meteorologist
WWL-TV
1024 North Rampart Street
New Orleans, LA 70116

[Kennethb]

Might be better for the energy to stay west. This would allow more moisture to work with. With a snow pack to our north, the air may not modify as much.

[TS Zack]

No keeping that ULL out West will not allow the Cold Air to come that far South. It is like the ULL will block it.

We go from dreaming of a White Christmas to a 100% Chance for a COLD RAIN. Errrrr.. This is reminding me of a good thing in which meteorologists don't forecast it and just say rain but we get more COLD Air then expected so we recieve snow. We flip everyday.

Saturday- SNOW
Sunday- No Snow
Monday- SNOW
Tuesday-No Snow
Wednesday-SNOW
Thursday- No Snow
Friday-SNOW!!!!!!!!!!!!

[PTrackerLA]

Hopefully the models flip back, I'll be very disappointed if we don't at least see some flurries.