Scientific Forecaster Discussion
fxus61 kbgm 211401
Area forecast discussion
National Weather Service Binghamton New York
1001 am EDT Sat Sep 21 2019
high pressure with warm temperatures well above normal through
the weekend. Expect valley fog each morning this weekend, then
sunny to partly cloudy skies. A weak front will bring scattered
showers and perhaps an isolated thunderstorm into the region on
Monday. High pressure returns by mid-week.
Near term /through Sunday/...
945 am update...valley fog is now rapidly burning off and
dissipating. Otherwise, latest GOES-east visible satellite shows
sunny skies across the entire area. Temperatures will warm
quickly today, reaching 77-85 by afternoon. Still looking at
some marginal instability late this afternoon across the far
western zones (steuben county). Latest guidance has backed off
on any shower/t'storm potential today, so have therefore dropped
pops from previous forecast...now less than slight chance
(around 10 percent). So overall, it's looking dry, warm and
sunny for the rest of today areawide. Still could see some
patchy fog tonight, but slowly increasing south winds should
prevent the coverage from being as widespread as the past few
nights. Fog may also mix out earlier. Will be watching 12z
guidance closely as some of the early morning guidance was now
indicating a low potential for isolated t'storms Sunday
afternoon. Sunday will be very warm and humid, with highs
reaching the low to mid-80s and dew points in the mid-60s.
230 am update...
Surface high pressure will remain in control of our weather
through the weekend. However, unlike the last several days, a
weak upper-level disturbance may bring some clouds or an
isolated shower this afternoon to far western zones.
NAM forecast soundings are indicating a little instability
building this afternoon across western New York and as a very weak
upper low/short wave pushes east from Ontario, an isolated
shower could be possible around Max heating. The one caveat is
the very dry air/subsidence in the low levels and the NAM is
likely a bit overdone with low level moisture as it usually is.
It will be very tough to punch through this layer and it could
be a case, with some decent mid-level instability, that some
Alto- cu develops and any rain will have a tough time reaching
the ground before it evaporates, so maybe just virga or some
sprinkles at best. Models also indicating a tight precipitable water gradient
though just to our southwest with values approaching 1.25"
across northwest PA this afternoon, compared to values only near
a half inch for our western zones. If some of that moisture
could advect a bit further west, then maybe some showers develop
this afternoon across Steuben County.
If any showers are to develop, they will quickly dissipate this
evening with the loss of heating. Valley fog may not be as
dense overnight and into Sunday morning, due to some stronger
low level flow and also the possibility for some cloud cover.
And not as cool with a steady south wind developing.
Temperatures today will be over 10 degrees above normal and it
should be a bit warmer on Sunday, but there is some uncertainty
on the amount of cloud cover Sunday afternoon that could keep
temperatures from increasing too much higher from today.
Short term /Sunday night through Tuesday night/...
3 am update...
This will be the most active period. A cold front moves west to
east through the area Monday. An upper level closed low crosses
on Tuesday with cold air advection and northwest flow.
Sunday night a deep southwest flow keeping low temperatures in
the 60s. Delayed the onset of showers until closer to sunrise
Monday morning. Models are slower. The cold front moves through
quickly Monday midday and afternoon with showers and maybe a
thunderstorm. Precipitable water values around 1.5" but speed
and dry antecedent conditions should greatly inhibit any flood
issues. Rainfall totals are under half an inch. High
temperatures range from the low and mid 70s in cny to around 80
in the Wyoming and middle Delaware valleys.
A deep upper level low moves east just north of the New York/Ontario
border Monday night. Some showers still possible with the cold
air aloft causing some instability. Best chance closer to the
low in cny. Lows in the 50s.
Tuesday the upper level low moves into eastern New York and New
England. Coolest day of the week with highs in the 60s and
mostly cloudy skies. Again the best chances of showers will be
cny. Showers will be enhanced some with moisture from the warm
Great Lakes and diurnal heating.
Tuesday night it dries out quickly as the low moves further east
and high pressure builds in at the surface. Low temperatures in
the 40s to around 50 warmest spots like Wyoming Valley and
Long term /Wednesday through Friday/...
3 am update...
Another mainly dry period with temperatures above normal. Upper
levels start out zonal then build a ridge in at the end of next
week. Models in better agreement with a cold front moving
through on Thursday with showers. Surrounding this wet period is
high pressure on Wednesday then again Friday into Saturday.
Highs mostly around 70 to the mid 70s. Lows mostly upper 40s to
Aviation /14z Saturday through Wednesday/...
high pressure with mostly clear skies and VFR conditions today
after dense valley fog dissipates around 14z. Winds will remain
light through the period and more valley fog is going to be
possible again late tonight into Sunday morning.
Sunday...VFR, except early morning valley fog for at least
kelm; possibly kith and kbgm for brief periods as well.
Sunday night through Tuesday...mainly VFR, but some restrictions
possible in showers as front crosses, especially Monday
afternoon and evening.
Wednesday...VFR conditions likely with high pressure building
in. May see some patchy fog at kelm in the morning.