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Saturday, January 29, 2011

Model Update #2 January 29

0z RUN
(Results compared to 18z run)

-WRF: Coming in a bit west.
-NAM: Same as 18z run.

Special Analysis Feb. 1-3 Storm



Below is a BUFKIT.
The measure on the left is if you melted all the snow expected, that is how many inches of water would come to. Multiply that number by 12 to get the expected snowfall.
The above is for Chicago. You can see how high the expected QPF is, leading to approximately 14-18''.
Below is a more significant image. It is forecast snowfall from the recent 18z GFS run. Notice how much snow falls over the South Great Lakes.
While these amounts may seem ridiculous, remember that the GFS model has been very consistent in the past at least 4 runs, making it the most consistent model of this storm.

The GFS and ECMWF, both the 2 heavy-hitter models, are north, while the NAM/WRF/GEM models are taking a southern track.
The UKMET model is dead in the middle.
Because the GFS/ECMWF models are the big models, I will take a mix of that and UKMET.
A special page is being set up for this storm.

Model Update January 29th

WRF and NAM have fled south, leaving the ECMWF the only one north.

MODEL ANALYSIS #1 Feb. 1-3rd storm

The GEM completely went on its own way.
The ECMWF may have gone south just a hair, but some areas' expected QPF (water equivalent of how much snow falls) actually went up.
GFS did trend a bit north, enough to bump up the expected snowfall totals and QPF as well.
NOGAPS is taking the GFS storm track.
NAM is still with the ECMWF storm track.
WRF also takes an ECMWF track.
While the time frame is still too early for the UKMET, early indications are taking an ECMWF track.

The interesting thing is: Although the GFS may seem far south to people in the South Great Lakes right now, a good foot is expected, and only more if it trends north.

MODEL DISCUSSION
-----------------
While the GFS has been the most consistent, I expect the GFS to trend more north and the ECMWF model only a bit south.
With the current set-up, it is now the ECMWF/NAM/WRF/UKMET? against GFS/NOGAPS
The GEM can be discounted due to its odd structure and track.
The GFS has been holding steady, as the ECMWF has.

It's the South 'camp' (tracks) against the North 'camp'.
Which one will break first?
Stay tuned to the Weather Centre for more information.

Predicted Snowfall Estimates (Feb. 1-3)

GFS: 10-12'' (At least 6'')
ECMWF: 1-3' (At least 6'')
NAM: Following ECMWF (At least 6'')
GEM: 8-12'' (At least 6'')
JMA: 3-5''
NOGAPS: unknown

Model Consensus: JMA model is a strange run, will discount it due to drop in snowfall estimates.
NAM and ECMWF are set on a very strong storm that could allegedly produce up to 3 feet in spots.
The GEM is forecasting 8-12'' and is reportedly trying to move north towards the ECMWF/NAM solution.
GFS solution is the most consistent, but with models and ensembles moving north, it is expected for at least a slight shift north in the GFS track.

MIDWEST FORECAST DISCUSSION #1 FEB. 1-3RD


MODEL FORECASTS
-------------------------

The ECMWF model has moderated itself and is now tracking through South IL.
The DGEX model has pushed northward and is now going through Central IL.
The GEM starts to go north, then suddenly drops to the Gulf Coast and continues on a very changed track.
The WRF, although still too far out in the time frame, says that early indications point to a northerly track.
The GFS says the storm will track along Tennessee moving Northeast.

HPC gives out high QPF rates

Much more interestingly, though, is a couple things for North IL/South WI
1. GFS predicts at least 6'' to fall- currently trending towards 8-12''.
2. ECMWF QPF says 1.75'' to 2'' of snow (17-20 inches of snow!!)
3. HPC QPF image above indicates at least 5-7.5'' of snow.

Model Consensus: A professional meteorologist mentioned that storms like these, although currently tracking south, often track north in the end.
Evidence of that happening is seen in the latest NCEP Ensemble, where all members are north of the 6z GFS.
The ECMWF may be trying to think ahead and stay north in event that the north track does happen.