Thanksgiving week forecast

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1. Kentucky weather conference a success in Bowling Green the last few days including the launching of a new statewide spotter network.

2.  Sunday should be a mostly sunny day with warm advection on the backside of the high entering the region. Highs should be in the mid 60’s east to upper 60’s/ 70? west after morning lows in the 46-52 range.  This is a touch warmer than other forecasts noting that dewpoints are around 50 at BWG now and southerly flow should offset radiational cooling somewhat.

3. On Monday a strong low pressure system will move around the ridge over the great lakes with rain to our northwest but we should continue to see an increase in clouds and southerly winds ahead of a frontal zone with a strong thermal gradient forming in the plains. Highs should be near 70 after lows around 50.

4. The frontal boundary will begin to slow as it encounters a strong southeast ridge through Wednesday waves of low pressure will travel along the boundary bringing periods of showers and some thunder with some training of rainfall possible along with locally hvy rains, perhaps on the order of 1-3 inches. Highs will be in the 60’s with lows in the 50’s, a smaller temp split due to cloud cover. Strong southerly winds will still be advecting moisture and warmth into the region. 

5. Model disagreement is present for turkey day on. The ECMWF model slows the front even more bringing another day similar to Tue/Wed while the GFS is faster with the frontal passage bringing in much colder air. Right now since these runs both play into typical biases of both models, I’m thinking the front comes through sometime Thursday with morning highs near 60 then falling temperatures during the day with a wind shift to the nw. Rain and thunder is likely early with overcast conditions the rest of the day.

6. Looking at just the ECMWF and GFS models give us a picture of a mostly cloudy and unseasonably cool day with highs only near 40 and strong nw winds. However several models and to some extent the ensembles have been trying to go with secondary low theory layed out here last week. With the cold air in place do we get another weaker wave to ride along the boundary and throw some precipitation back into the cold air on Friday. If so thermal profiles may be need to be examined on Friday as precipitation could be in the form of snow. Often models show these features 7-10 days out then lose them for a few days only to have that solution come back again, this is worth watching. As for now I would not be to hopeful of a snowy black friday only expecting the cold.

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11 Responses to “Thanksgiving week forecast”

  1. tornadolarkin Says:

    The canadian model is pretty extreme on its secondary low.

  2. mitchg Says:

    yup. 18z gfs trending somewhat in the direction of the secondary low. 00z gfs tommorow should not have it though as that is typically the most supressed run of the 4 op gfs runs. GFS may be putting to much on northern branch. however i still don’t see enough to think it’s going to happen.

  3. tornadolarkin Says:

    Well, at least we have somthing(s) to track this coming week.

  4. mitchg Says:

    chances for a period of snow friday morning are present.

  5. mitchg Says:

    of course need to see 00z ecmwf before jumping on board.

  6. mitchg Says:

    gfs ensemble mean a average of gfs runs data showing a slower frontal passage rain to snow friday then snow friday night but with enough qpf to makes it intresting. attention level toward the potential increasing slightly.

  7. mitch Says:

    heavy rain most of the week still expected. first batch Tuesday, second round turkey day. Then a change to snow is still possibile. GFS shows 1-2 inches falling from the air, not going this far yet but check back later for more.

  8. mitch Says:

    gfs map this is snow falling from the air the ground is very warm now likely over 55*F for soil temps.
    http://wxcaster.com/gis-gfs-snow-overlays.php3?STATIONID=LVX

  9. tornadolarkin Says:

    Check this out:
    http://wxcaster.com/gis-gfs-snow-overlays.php3?STATIONID=LVX
    That would be insane for black Friday.

  10. Seth Says:

    Random Theory: I was thinking that since the precipitation for the last wave starts out as rain, once the freezing line drops through the state, that wet surfaces would freeze up and be rather slick perhaps making it a bit easier for snow to accumulate.

  11. mitchg Says:

    actually harder for snow to accumlate on wet ground.

    update later tonight after finishing stuff for my classes.

    1. rain tommorow
    2. severe threat wednesday
    3. rain again, heavy on turkey day
    4. change to snow for friday

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