One reader wanted to know how to get the latest hourly probability of precipitation for our area.

One of the best ways is a direct link to the NBM (Model Blend) text output. The NBM is considered the best model for rain probability and the model data from this link is updated every few hours.  (Yes, the NBM model is updated every hour, but to get the absolute latest, you’d have to dive into the bowels of the NOAA NOMADS server.)

I’ve pre-configured the URL for you to provide the model output for Philadelphia Airport, Wings Field Blue Bell, and Northeast Philadelphia airport—

https://www.weather.gov/mdl/nbm_text?ele=nbs,nbe,nbh&sta=klom,kphl,kpne

The one you want to focus on is the NBH ( H= hourly).

It provides hourly probability (P01) in percentage (on an hourly basis, anything greater than 18% and increasing is meaningful) and the amount (Q01) in hundredths of an inch. 

It’s important to know, that with accumulated rainfall, the number refers to amount having accumulated in the preceding hour.

The tricky part is converting to the UTC time to Eastern Standard or Eastern Daylight time. 

The example below is for KLOM, Wings Field, Blue Bell.

So in the example below, this is the NBM model run is from 0700 UTC (3 AM EDT).  The first row (labeled UTC)  are the forecast hours and the column labeled “14” is the UTC TIME forecast time. So  14UTC = 10 AM EDT (or 9 AM EST).

Looking down the 1 hour probability (P01) is 48% and the quantity of rain fallen in the preceding hour (Q01) is 2.   2= 0.02″

Beware that for some of the other data displayed, especially in the NBE, the meaning can less less than intuitive.  In the NBE, the column labeled, as an example,  00 day FRI, refers to the 12 hours PRIOR to 00z Friday which means daytime THURSDAY!