Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
400 PM EDT Friday Jul 25 2014
high pressure will bring dry cool weather across the area tonight.
A series of low pressure systems will move across the area late
Saturday through Monday bringing a chance of showers and
Near term /until 6 am Saturday morning/...
scattered cumulus will dissipate with sunset this evening setting the stage
for a mostly clear and comfortably cool night. Some middle and high
level cloudiness will increase across the area toward daybreak.
These clouds should be enough to keep valley fog from being as
widespread late tonight as this morning. Lows will range from the
upper 40s to the 50s.
Short term /6 am Saturday morning through Monday/...
a series of short waves will affect our area from Saturday
afternoon through Monday as an unseasonably strong long-wave trough
digs southeast across the Great Lakes toward the East Coast. The
first short wave will swing across the area late Saturday. Clouds
will increase ahead of this system by early Saturday... with
partly to mostly cloudy skies continuing through Saturday
afternoon. Dew points will gradually increase through Saturday and
a little instability will develop by late in the day... this may
be enough to trigger a few showers or thunderstorms with the
passage of the short wave Saturday afternoon through Saturday
evening. Probability of precipitation for this first wave will maximum out around 40-50 percent
The pattern gets more complex and uncertain later Saturday night
as moisture continues to increase across the area in southwest
flow. At this time it appears that a convective complex will
likely track southeast from the Ohio Valley across the Middle-
Atlantic States Saturday night probably remaining south of our
area. However the increasing moisture... instability and moisture
flux associated with 20-30 knots low-level SW flow may be enough to
keep scattered showers and thunderstorms going through the night
especially given that our area will be in the favorable left exit
quadrant of an upper jet moving east moving east from the Ohio Valley.
Probability of precipitation Saturday night will range from 40 to 60 percent.
Dew points will be well into the 60s on Sunday with moderate
instability associated with cape values at or above 1000 j/kg.
However the large-scale forcing for precipitation on Sunday will
be questionable as one system should be moving east of the middle-
Atlantic early in the day while another even stronger system
approaches from the west. Details on Sunday are highly uncertain
at this point but it certainly appears that there will be at least
a chance of showers and storms given the instability and cyclonic
upper flow which may contain a short wave trough. Kept probability of precipitation Sunday
in the 30 to 50 percent range which is reflective of this
uncertainty. Given the moderate instability and middle-level winds of
30-40 kts any storms that do develop could approach severe limits
during the afternoon or early evening. Have kept the mention of
severe weather possible for Sunday afternoon in the hazardous
The best chance for showers and thunderstorms during the next
several days may be Sunday night and Monday as the main upper
level trough advances east from the Great Lakes and Ohio Valley.
With moderate amounts of instability present details will be
highly uncertain as there could well be another mesoscale convective system moving east-
southeast from the Ohio Valley. However forcing may be strong
enough for the development of a widespread area of showers and
storms. Based on this have gone with probability of precipitation increasing to around 60
percent from late Sunday night through Monday. Given the moist
atmosphere with precipitable water values probably over 1.5 inches
heavy rain will certainly be a possibility by Monday and this will
need to be monitored.
Long term /Monday night through Friday/...
2 PM update...
have followed wpc guidance as medium range models are in good agreement
on overall pattern with a strong ridge in the west and deep trough
in the east through the end of the long term. Discrepancies exist
with regard to surface pattern as 00z ec has well-developed surface low along
the New York bight 12z Tuesday while 12z GFS and CMC have a surface trough along
the East Coast at this same time. More than half of the GFS
ensemble members have some semblance of a surface low at the same time.
Only impact this has would be how high to go with probability of precipitation for Tuesday as
any surface low in the area will add to the convergence and combined
with diurnal heating this would likely boost probability of precipitation into the likely range.
Given the uncertainty that exists have kept probability of precipitation in the chance range
for Tuesday for showers, which is basically what wpc has.
Each afternoon will have the chance for shower activity due to diurnal heating as
ul trough lingers across eastern half of the nation. Temperatures will begin to
slowly moderate after frontal passage occurs on Tuesday morning with highs in the
u70s and lows in the l50s.
Aviation /20z Friday through Wednesday/...
a few renegade cumulus clouds are floating over terminals under a
smoke layer. After 00z, VFR clouds will dissipate leaving just a thin bkn200
deck over terminals. Middle-deck expected to move in as upper level
system works in after 15z Saturday.
Once again the question for tonight becomes fog potential at Elm.
Winds just above the surface are stronger than last night and with
IFR only occurring for 30 minutes this morning, think the chances
are probably even less for tonight. Thus have kept just 2sm visibilities
between 08z and 12z Saturday for Elm.
West-southwest around 5kts will become light/vrb after sunset tonight, then
increase to between 5-8 kts from the southwest after 15z Saturday.
Sat night-Monday night...potential restrictions in shra/tsra.
Tue/Wed...restrictions possible each afternoon in afternoon rain showers.