Thursday, January 21, 2010

[UPDATED Friday Evening] Detailing the GFS...

I am going to update this blog entry until think we have something that requires a new entry. Look to the bottom for the updates.

The GFS has been pretty good showing the system next week so I think it might be fun to take the latest run and just detail it out.

It starts off badly on Thursday morning for school decision makers. Snow will be forecast and to be heavy by the afternoon but will just be starting about the time buses roll for school. At 1 PM, snow will be increasing in intensity. By now there will be 3 to 4 inches on the ground. Moisture will be ample at 700 mb and the Gulf of Mexico is getting ready to open up wide. Some good news is the winds will be around 5 to 10 MPH. Thicknesses are excellent. Is this system prefect, no. The system from the north doesn't phase with the system from the south until it is well past us.


Twelve hours later and the rubber is meeting the road. Another 4 to 6 inches has fallen and with the low now over Columbus, OH, winds have wrapped around to the northwest at 12 to 15 MPH and gusting to 20 MPH. The temperatures have also begun to nosedive into the low 20's.


Of course Friday is a snow day and an easy call for once. I doubt anyone will even need to drive the roads to make the call. The system finally quits snowing Friday afternoon after after 30 hours. We now have 6 to 10+ inches on the ground. Winds are really churning the snow now with 20 MPH gusting to 30.


Things finally settle down by Saturday morning and having a foot of snow on the ground is not unfathomable. This is a heavy wet snow. We are in single digits with the temperatures and blowing and drifting is still a problem. Some bad news, I won't get one or two snow days since this falls on the weekend. Oh well...

I won't post maps but by Monday afternoon, another but less powerful system comes up through the south and drops another 2 to 4 inches through Tuesday. Temperatures will hover around 20 degrees and winds will be 5 to 10 MPH gusting to 15 MPH. Since the previous system's snow will still be on the ground, consider Tuesday another snow day.

The end of the week shows a clipper dropping down and another couple of inches to pile on.

Of course this is just a fictional account of the 18z GFS model run. There will be many more possible solutions presented over the next week and I think we need to get this weekends rain and possible severe weather event out of the way before the models start to show what will really happen. But we can dream and the several models have the system and various states including a nice phase which would make my fantasy forecast above look like a tea party.

A weather friend of mine alerted me to this tasty treat. The CPC (Climate Prediction Center) does 8-14 day analog comparisons. The map below is right in the time frame of the scenario outlined above. In the lower right, it points out dates that are very similar with the overall pattern. Notice the 1978 blizzards are comparable analogs. Many that sure would be sweet if this verifies.

[Friday AM Update] So I has asked if I believe that next weeks snow storm could be like the blizzard of 1978. While the pattern may resemble 1978, it won't be nearly as bad. We won't have have the bitter cold and the winds won't be nearly as strong or last as long so I don't think true blizzard conditions will happen. Also, one thing has changed since the blizzards of the late 70's...

In those days most fields still were bordered by fences. On rural roads, snow would fill in and drift between the fences. Today most of those fences have ben removed so that doesn't happen as bad anymore.

The NOGAPS shows a nice phase and system.



[Friday Evening Update] When can we begin to believe? Lots more model support. The DGEX model is on board and the 18z GFS cranks it up a notch. Think 12-18 inches plus of snow! WOW!



DGEX

Area Forecast Discussion from Indianapolis

IN THE EXTENDED...TRANSITION TO A MUCH COLDER PATTERN 
LOOKING INCREASINGLY LIKELY AS DEEP UPPER TROUGHING
REESTABLISHES FOR MUCH OF THE EASTERN U S. MODEL
CONSENSUS FAVORING THE POLAR VORTEX TO SLIDE SOUTHEAST
INTO THE UPPER GREAT LAKES AND NORTHWEST FLOW AT THE
SURFACE. IN WAKE OF THE DEEP LOW PRESSURE ON SUNDAY...
TRAILING UPPER LOW WILL PASS THROUGH THE LOWER GREAT
LAKES MONDAY INTO EARLY TUESDAY. HAVE MAINTAINED CHANCES
FOR SNOW SHOWERS BOTH DAYS. COLD HIGH PRESSURE WILL THEN
BUILD IN FOR MIDWEEK. LARGE MODEL DISAGREEMENT FOR LATE
WEEK IN RESPONSE TO UPPER LEVEL ENERGY EJECTING OUT OF
THE SOUTHWEST. MODEL CONSENSUS DOES APPEAR TO FAVOR
LOW PRESSURE DEVELOPMENT OVER THE SOUTHERN PLAINS...
LIFTING NORTHEAST INTO THE OHIO VALLEY THURSDAY AND
FRIDAY. MODEL DIFFERENCES IN TIMING AND FEATURE PLACEMENT
AS WELL AS AMOUNT OF PHASING BETWEEN THE SUBTROPICAL AND
POLAR JET ENERGY ARE GREAT AT THIS POINT. HAVE INSERTED
LOW CHANCES FOR SNOW SHOWERS AT THIS TIME...BUT WILL
CONTINUE TO MONITOR OVER THE NEXT SEVERAL DAYS.
TEMPERATURES WILL GENERALLY REMAIN BELOW NORMAL THROUGH
THE PERIOD...WITH HIGHS IN THE UPPER 20S AND LOWER 30S.

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