Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
154 am EDT Monday Apr 27 2015
a few upper level disturbances will drop southward across the
region tonight through Monday with a few showers expected from
late tonight through Monday evening. Temperatures may be cold
enough...late tonight into early Monday...for wet snow showers
over the higher terrain. High pressure will build south across the
region for Tuesday and Wednesday with fair weather and moderating
Near term /through today/...
945 PM update...only a few holes developed in the strato cumulus this
evening and these are beginning to fill in as deeper moisture
drops south as upper level low retrogrades slightly along with
a middle level short moving through southern Ontario. Forecast in
good shape just minor adjustments made to short term cloud/temperature
visible satellite imagery shows widespread broken-overcast stratocumulus
clouds across most of central New York and northeast PA as a low-level northerly
flow of air continues to strengthen over the region as a short
wave passes south as per WV imagery. The ll northwest flow that has set
up was leading to a Lake Shadow into the upper Finger Lakes but
there was still scattered-broken cumulus in these areas. Models indicate a
few isld rain showers could pop up over the higher terrain regions where
upsloping and strong enough heating will lead to some convective
rain showers. So we have mainly sprinkles in these spots as the air mass was
For this evening...think the clouds will wane for a time with the
loss of the day/S heating so there could be some partial clearing
for a time after sunset. This will occur before a moist layer between
850 and 925 mb advects southward and reaches NC New York around 4-5z and
down to NE PA late tonight around 9-12z. As a result clouds will
increase again later tonight. With another spoke of energy
rotating around the closed low off the Maritimes some light shrasn
or sprinkles/flurries will reach The Finger lakes to Upper Mohawk
valley between 9 and 12z. Rest of c New York and NE PA will be dry
For Monday...ll northwest winds and ll moisture will combine with the
day/S heating for scattered rain showers or sprinkles which could mix with snow
flurries at times early. Model soundings all support this
convective acvty. Precipitation will be light and short lived. We are expecting
mainly a broken-overcast day and it will remain quite chilly with highs
from the upper 40s to the 50s...much like today.
Short term /tonight through Wednesday/...
for Monday night...residual rain showers will taper off with the waning
diurnal heating with clouds lingering most of Monday night as per the
925 mb and 850 mb relative humidity fields. By Tuesday into Wednesday...a narrow
ridge of high pressure will build south into the region from the
surface through 500 mb with dry weather and less and less clouds by
Wednesday and moderating temperatures.
Long term /Wednesday night through Sunday/...
GFS and Euro are slowly coming into agreement on the closed low and
developing coastal system in the long term...with the GFS trending toward
the Euro. Long WV pattern is similar with flat ridging into the Upper Middle
west. Dfrncs continue to Stem from the handling of a northern stream WV
dropping into the east CST trough...and it/S interactions with a
strong southern stream system. Euro continues to keep a separate and
dominant southern stream storm moving off the middle Atlantic CST...keeping
a weak trough to the north...while the GFS wants to rapidly deepen
the northern WV and capture the southern WV resulting in a deep system off
the CST and a closed upper low over western New York. GFS solution wld likely
produce a colder and wetter scenario...perhaps some snow...for the
forecast area. Euro wld continue to keep the area below normal...but much lighter
and all liquid on the precipitation.
With the GFS/S tendency to create bogus deep storms in the long
term...will continue to follow the Euro solution and keep low chance probability of precipitation
with below normal temperatures for much of the extended period. This also allows for
a continued gradual imprvmt in the weather into the first part of the
weekend...although some light precipitation cannot be ruled out.
Aviation /06z Monday through Friday/...
a few upper level disturbances will drop south through the taf
period as we will remain in northerly flow aloft. These
disturbances will create an environment conducive for showers.
Showers will be temperature dependent... thus areas where temperatures
are near or below freezing will see snow... and with temperatures above
freezing... precipitation will be rain. The chance for rain will prevail
over much of the region starting around sunrise and last through the
afternoon and evening. At this time... VFR conditions prevail across the
region. Northerly flow generally creates downsloping... thus
believe we will just see a brief period of MVFR ceilings early this
morning and sites will see mostly VFR for much of the forecast.
After 00z tonight... the flow will transition to a more
northwesterly flow... and the chance for low end MVFR and IFR ceilings
increase. At this time... put low end MVFR at kbgm and ith as confidence
is the high.
Winds will become westerly and gusty this afternoon with an
occasional gust around 20-25 knots.
Monday night...possible MVFR/IFR ceilings at times due to the cool northerly flow.
Tuesday - Thursday...mainly VFR.
Friday...possibly MVFR-IFR restrictions with rain and br.