Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
353 am EDT Sat may 23 2015
after a cold start to the day...full sunshine will get
temperatures into the upper 50s to middle 60s range for highs. Dry
conditions will continue through the remainder of the Holiday
weekend...though the chance for showers and eventually thunder
will gradually increase by Monday night into Tuesday. Temperatures
will also warm through the period...with mainly 70s for highs
Sunday...and then 80s Monday Onward.
Near term /through Sunday/...
345 am EDT update...
frost-freeze remains the main concern early this morning. It may
not be quite to the degree that was initially feared for some
areas...but still a fair amount of frost and for some locations
below freezing temperatures which will damage vulnerable plants.
High pressure center is currently moving from Lake Erie into
western PA...so there has still quite a good pressure gradient
over our region much of the night. Winds stayed up the first half
of the night but are finally decoupling especially the more
sheltered deeper cut valleys. Cortland-Ithaca-Norwich-Oneonta
are calm right now...and Ithaca-Norwich have even hit freezing
prior to 4 am. Most cooling had been simply air mass related
earlier in the night...but radiational cooling is now more into
play the last few hours of the night as pressure gradient slackens
and winds have decoupled. On average it appears lows will end a
degree or two milder than prior thinking...and regarding frost-
freeze that is an important couple of degrees in terms of how much
vegetation damage may be incurred. The other factor...is the very
dry air mass with dewpoints mainly in 25-30 range. This may
somewhat limit coverage of frost for areas that do not actually
reach all the way to freezing /though rooftops and cartops as
usual will be more frost-prone/. Frost-freeze headlines remain up
on a County scale...but for some pockets such as Syracuse metropolitan in
New York and Wyoming Valley in PA...frost will be quite patchy in nature
and miss some areas.
Full sunshine today. For highs I went a touch above blended
guidance...since this set up /dry air above subsidence inversion
from building high pressure/ often leads to the models not being
quite dry enough with dewpoints nor high enough with
temperatures...that is not wide enough with dewpoint depressions.
So after the chilly start...expecting upper 50s to middle 60s for
Warm air advection already begins tonight...with center of
surface high already shooting off the midatlantic coast...and
return flow beginning. Some of our coldest pockets such as the
Chemung River Valley could sneak into upper 30s...but for most
locations expecting lows in 40-45 range. Though central New York could
get skimmed by scattered high clouds...a mostly clear sky.
Warm air advection gets more fully realized Sunday...in the form
of high temperatures in the 70s...a good 10-14 degrees up from
Saturday. Though high thin clouds will start increasing from the
west late in the day...overall still plenty of sun with a warming
wind from the west-southwest.
Short term /Sunday night through Monday night/...
changes to the forecast for this period as guidance has been
backing off on precipitation for Sunday night and Monday. Ridging looks
to hold pretty strong over the area during this period so even as
warm front lifts north best moisture and low level convergence looks
to now be mainly north/west of the forecast area. Therefor, have scaled
back probability of precipitation.
Look for clouds to increase Sunday night as light SW flow and warm air advection
set up over the area. Maintained the slight chance of showers
over the lake plain but otherwise conditions should be dry with
lows in the 50s. Memorial Day now shaping up to be a warm and
mainly dry day with a mix of sun and clouds over NE PA through the
twin tiers and partly to mostly cloudy skies farther north where
we kept a slight chance of showers in the forecast. As 850 mb
temperatures rise to 14c +, forecasting highs in the low to middle 80s
however dew points still won't be too high just yet...generally in
For Monday night, dew points creep up to near 60 as warm, moist
southerly flow continues. This will cap lows off from dropping
below the low to middle 60s. There will be the slight chance of a few
showers as daytime storms from Ohio and S Ontario drift east and
weaken but otherwise it should stay mainly dry.
Long term /Tuesday through Friday/...
fnt fnly lifts north of the area Monday night lvg warm and humid air
over the region. SW flow surface and aloft will contribute moisture
while daytime heating helps develop lift so despite being under hipres
the risk of showers and trws will continue into the extended period.
Really little change through the period as the fnt over the Midwest trudges
very slowly east. Upper ridge in the western Atlantic stubbornly resists
the fnt and slowly weakens and shunts it off to the northwest. So...
chance of showers and trws continues into Thursday... with the better chance
over the west and northern zones. While continuing above normal...temperatures will
tend to fall later in the period as a slow increases in clouds and moisture
will limt heating.
Aviation /08z Saturday through Wednesday/...
VFR with high pressure in control...and air mass is too dry to
support nighttime valley fog even in kelm. Variable or light northwest
wind during predawn hours...will back more westerly at about 7-11
kts during the day...then variable or light SW tonight.
Monday night-Wed...restrictions possible in scattered rain showers/daytime thunderstorms and rain.
PA...freeze warning until 9 am EDT this morning for paz038>040-043.
Frost advisory until 9 am EDT this morning for paz044-047-048-
New York...freeze warning until 9 am EDT this morning for nyz009-017-018-
Frost advisory until 9 am EDT this morning for nyz015-016.