Scientific Forecaster Discussion
fxus61 kctp 191431
Area forecast discussion
National Weather Service State College PA
1031 am EDT Sat Oct 19 2019
high pressure remains in control today. However, rain
associated with tropical storm Nestor may clip southern parts of
the region on Sunday as the storm center passes well to our
south. The best chance for a more widespread rain looks like it
will not be until Monday night and Tuesday when a cold front
will move through.
Near term /until 6 PM this evening/...
morning vis imagery indicates some stubborn valley fog mainly in
areas mainly north of I-80. Expect these to mix out by late
morning with full sunshine for everyone for a while.
Sunshine will be increasingly filtered by the high clouds
coming off Nestor. But, mostly sunny will work just fine for
wording. Ridge axis keeps moving to the east and we should have
light southeast wind in the aftn. This should help boost temps another
5+ degs f over Friday. Maxes generally near normal, but could be
quite a bit above normal with temps over the northwest mtns getting
into the upper 50s.
Short term /6 PM this evening through 6 PM Sunday/...
clouds thicken up tonight as they invade from the S. Mins will
be held much warmer than Sat am, with u30s in the nrn mtns and
m40s in the S. The low center of Nestor will pass well to our S,
with most guidance rolling it over Virginia Beach and out to sea. This
track paints the quantitative precipitation forecast mainly S of the state, but light rain will
probably brush the area staying south of the Turnpike on
Sunday. However, the NAM and some supporting members of the href
push decent rainfall well into central PA as it has the low
passing over srn Delaware. In fact, the NAM paints more than an inch
of rain over the sern third of the County Warning Area. While the European model (ecmwf) was
pushing the rain farther north into the County Warning Area with the 00z/18th
run, it backed off with the 12z run and is currently (00z/19th)
keeping most of the rain S of the border. It still makes a
tenth or so over Lancaster co, but keeps it all dry north of I-81.
This is in line with our current pops. Not feeling particularly
Brave enough to totally remove pops from our central counties at
this point. But, we will trim them slightly with an eye toward
what the offices to our S/east are doing with pops there. Will keep
temps in the u50s and l60s on sun with higher numbers in the northwest
where the clouds will not be too thick. Most models scoot the
rain off to the east in the early aftn.
Long term /Sunday night through Friday/...
clearing under high pressure Sunday night into Monday.
Ribbon of anomalous pwats ahead of next frontal system will
likely bring moderate rain to the sometime between Monday night
Tuesday night. GFS is faster vs. European model (ecmwf) so a compromise is
favored for timing. Latest model trends indicate a more
progressive system which would keep rainfall amounts somewhat
in-check. The best chance for heavy rain (prob of 1"/12hr) is
focused over the eastern 1/2 to 1/3 of the County Warning Area. Mainly dry
weather should follow for mid to late week.
Blocking high over Greenland seems to allow for a potentially
stronger system to evolve over the eastern U.S. Next weekend.
Aviation /15z Saturday through Wednesday/...
satellite loop showing fairly widespread valley fog across
central PA early this morning. Any fog will dissipate by
around 13z-14z, then VFR and light wind will prevail the rest of
Sun...light rain/low cigs possible southeast PA.
Mon...am valley fog.
Tue...rain/low cigs possible.
Wed...no sig wx expected.