Yesterday’s cloud base did lift and thin, but we never saw the degree of clearing that was forecast by the HRRR or NAM-NEST models. Showers moved in, as expected, about 5 PM, but the northern-most extent and their duration into the evening hours was greater than predicted by any model.
For today, (similar to last Sunday), several upper air disturbances are causing the cloud deck right now. Sun should break out later this morning, but another upper air disturbance is expected about 4 PM (not talking about the Eagles here.) So, another period of cloudiness possible later.
The coastal storm for mid-week mentioned in last Friday’s post remains difficult to forecast. The NAM and Canadian GDPS have 1-2 inches of snow (less in the city) late Tuesday afternoon into evening. The GFS shows less development and a coating at most. The GFS has done the best this season with these storms. This storm is still beyond the range of the shorter range models. Stay tuned.
[su_note note_color=”#defcdc”] Update 10 AM: I just downloaded the new HIRESW NMMB2 and HIRESW ARW2 (yes, so many models, so little time.) They are a little less optimistic about clearing. At best, patchy clearing with highly scattered sprinkles possible, increasing about 4-5 PM.
Well, we’re going to get a bike ride in, I hope.
The low clouds and widely scattered showers were expected this morning.
I just downloaded the very latest NAMNEST, HRRR and RAP model data.
All models have winds shifting to the west about 11-12:30 PM, bringing in some drier air. The HRRR is most optimistic about seeing some sun and bright skies by 12-2 PM. The NAM NEST also has brightening skies by 2 PM, although not as clear as the HRRR.
I’m using the (sometimes unreliable) built-in cloud parameters, but clearing also supported by looking at the humidity fields.
The models maintain an increased chance of showers again about 4-7 PM as the main front moves through and again this evening.
We’ll see if the patchy clearing occurs as predicted.
My snow forecast last night of “a coating at best” needs to be revised downward to virtually nothing.
Temps remain even warmer than predicted (34 º+) and available moisture is very low right now. QPF was only predicted at 0.01 inches water per hour and that’s turning out to be model noise.
Current radar is unimpressive:
So with predicted precipitation so small, most of the models showed model noise as precip. (Looking back, the Canadian high resolution model from last night got this right.) Heavier rain is expected tonight.