Category Archives: Updates


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.


This post was revised

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.

HIRESW NMMB2      2 PM Simulated Radar and cloud cover

Well, we’re going to get a bike ride in, I hope.

…from earlier—

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.

HRRR cloud forecast 2 PM  (Arrow shows clearing skies)
NAMNEST Cloud Forecast 2 PM  Arrow points to few clouds.
NAM 3-D humidity below 70% (grey, not blue here!) shows areas of clearing.

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:

NEXRAD    (Courtesy of

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.


The experimental US Navy COAMPS-TS did a great job at predicting the movement of Hurricane Dorian. It looks like the Navy is tracking several other tropical storms/disturbances and they haven’t released an update on Dorian since early Monday morning.

(I can only guess that their experimental modeling work needs to share computer resources with modeling of other tropical storms.)

Nonetheless, this is the latest COAMPS-TS track available, which is  similar to previous predictions with this model. The storm is not expected to directly hit the Florida coast.   It’s current predicted track is remarkably similar to that posted this past Friday.The vast majority of the other major models have similar tracks for Dorian, as of Monday afternoon.