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fxus61 kbgm 201050 

Area forecast discussion
National Weather Service Binghamton New York
650 am EDT sun may 20 2018

a passing cold front, will bring hit and miss showers to the
area, through about midday, with clouds eventually breaking,
for some late day sunshine. Weak high pressure, will build over
the region, tonight through Monday, with dry and seasonable
weather. Showers will creep back into the forecast, later Monday
night and Tuesday, as the next disturbance moves through.


Near term /until 6 PM this evening/...
3 PM update... scattered showers continue to dot western and
northern New York early this morning, just ahead of an approaching
surface cold front. It continues to appear that this front will
cross much of the forecast area rather quickly today, ultimately
pushing through the Poconos and western Catskills during the
early afternoon hours. Low-level convergence with the front
itself, along with some forcing from a northern stream short-
wave, sweeping by just north of Lake Ontario, will continue to
produce widely scattered showers. Model guidance suggests that
some marginal instability develops for the midday and early afternoon
hours, and we've thus maintained the mention of isolated
thunder until frontal passage.

Behind the front, trapped low-level moisture underneath a
building subsidence inversion, should keep some Post-frontal
clouds for a while this afternoon, especially over portions of
cny. However, by late afternoon, enough drying should reach the
boundary layer to promote clearing skies area-wide.

Temperatures will be a bit coolish today across our northern
areas (highs in the 60s), owing to a faster frontal passage,
while our southern areas of nepa and Sullivan County, New York are
likely to climb into the 70s.


Short term /6 PM this evening through Monday night/...
310 PM update... as weak surface high pressure and short-wave
ridging aloft build across cny and nepa tonight and Monday, we
can expect clear-partly cloudy skies. Tonight's clearing, along
with diminishing winds, and wet soils from recent rain, should
lead to late night valley fog.

Lows tonight should end up within the mid 40s-lower 50s range by
daybreak. On Monday, we should see a fair amount of sunshine
after morning fog Burns off. Given such insolation, and also the
fact that low-level warm advection will already be under way,
afternoon hours should climb well into the 70s for most locales.

Monday night, model consensus points to the re-development of a
S-SW low-level jet. This jet will act to rather quickly
transport moisture back into cny/nepa, while also providing an
increase in warm advection forcing, especially as the next
short-wave aloft approaches from the west. Thus, we introduce
showers back into the forecast, first over nepa and our far
western zones, eventually spreading to the north and east as the
night wears on.


Long term /Tuesday through Saturday/...
345 am update...
confidence has increased for rain-embedded thunder into Tuesday
as models are in better agreement. Chances of showers were
raised into likely range for northeast PA and southern tier-
southern Finger Lakes New York. Weak cold front then passes late
Tuesday night-early Wednesday. Wednesday itself continues to
look mainly dry; only maintaining a slight chance for a Post
frontal shower but incoming surface high will probably provide
enough subsidence to make lingering clouds fairly shallow, and
diminishing with time.

Previous discussion...
under a broad upper level trough to start then a ridge Friday
and Saturday. Temperatures start out at or a little above normal
then rise a few degrees end of the week. Highs mainly in the
70s for the week. Lows mainly in the 50s but some mid and upper
40s a few nights midweek. No sign of frost.

Clouds and showers continue Tuesday. Maybe a thunderstorm
Tuesday afternoon. Depends on the low track and timing. On the
NAM and GFS the track is through western New York in the afternoon.
The Euro is weaker with hardly any low and a front draped across
PA all day. Kept the chance of thunderstorms for the western
County Warning Area where the instability should be better but still meager.
Tuesday night most of the showers exit. Models not agreeing on
Wednesday showers so only slight chance pops.

High pressure builds into the area Wednesday night with dry
weather, that last into Friday night. The next system approaches
Saturday from the west. This is a slow mover with lots of
moisture moving north out of the Gulf ahead of it.


Aviation /12z Sunday through Thursday/...
12z update... restrictive conditions will continue at most
terminal sites through at least 15-18z, owing mainly to lower
ceilings, but with some passing showers also coming through.
Kbgm, kith, and kavp should see at least some IFR. Kelm, ksyr,
and krme will see mostly fuel alternate restrictions.

By mid to late afternoon, clearing skies will bring a return to

Later tonight, with good radiational cooling foreseen, and wet
ground conditions from recent rainfall, fog development seems
like a good bet. Fog/IFR restrictions were introduced at several
terminals after 06z.

S-SW winds 8-10 kt through late morning, will switch to northwest by
afternoon. Winds should diminish towards sunset.


Monday...probable early morning fog, will give way to VFR.

Monday night through Tuesday night...chance of restrictions, in
periods of showers and thunderstorms.

Wednesday and Thursday...mainly VFR.


Bgm watches/warnings/advisories...
New York...none.



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