STORM2K

Look at this 12z GFS!!!!!

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_084l.gif

4"+ across E PA/NJ!

This may cause a whole lot of flooding problems...12z ETA has more of a 1-3" rain event.

Does look like a miserable few days coming up with lots of drenching rain. However, as LWX mentioned this morning in their AFD, flooding is not necessarily a huge concern considering the below-average precipitation we've seen since the beginning of the winter season.

Also, FWIW, the forecaster noted that the GFS was having "convective feedback" problems that may have been illegitimately increasing QPF output... not that I claim to know what that means .

brettjrob wrote:Does look like a miserable few days coming up with lots of drenching rain. However, as LWX mentioned this morning in their AFD, flooding is not necessarily a huge concern considering the below-average precipitation we've seen since the beginning of the winter season.

Also, FWIW, the forecaster noted that the GFS was having "convective feedback" problems that may have been illegitimately increasing QPF output... not that I claim to know what that means .

Bingo ... The GFS is notorious for developing (overdeveloping) QPF when large clusters of thunderstorms (or severe thunderstorms) are involved. I've tend to notice with large clusters of thunderstorms that the GFS overemphasizes mesoscale lows involved with MCS/MCC's and voila ... it goes ape with precip.

What HPC says about the convective feedback bias ... (link below)

http://www.hpc.ncep.noaa.gov/mdlbias/biastext.shtml#GFS

Exactly. The GFS has been notorius for showing too much Quantive Precipitation Forecast especially in the northern locations. This has to do with a number of things, but mainly the warm moist and cool dry air colliding along a coastal region. I find that the MRF is better for precip forecasts, where the GFS is better for development of a system. But, the GFS also has further problems such as the forecast track of low/high pressures, whereas, the NOGAPS is better fopr forecast tracks during the same period.

QPF's are higher in the eastern Gulf of Mexico compared to the E PA/NJ.

Regardless of the GFS' apparent overdevelopment of large clusters of thunderstorms; tthe National Weather Service offices (as Johnathan mentioned in another thread) in Florida are watching this situation closely.

in speaking to my mother in PA last night, she commented that wet snow was forecast to mix in. did it happen? p

Altoona received some snow