Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
438 am EDT Tuesday Jul 22 2014
warm muggy weather will be with US through Wednesday. Although an
isolated thunderstorm could develop this afternoon or
evening...much of the time today and tonight will be rain-free.
Showers and thunderstorms will be more likely on Wednesday...ahead
of an approaching cold front. Cooler less humid conditions will
follow behind the front later this week.
Near term /until 6 PM this evening/...
415 am Tuesday update... middle-level cloud debris covers most of the twin
tiers early this morning. Although these clouds are expected to become
more patchy with time...coverage will likely be sufficient to
prevent widespread or dense valley fog through daybreak.
Later today...warm sticky conds are anticipated under hazy sunshine...with
afternoon highs well into the 80s...and surface dew points well into the 60s.
Although this will lead to some air mass destabilization...warm middle-level
temperatures and residual capping in the 700-600 mb layer will temper this
a bit (expected ml convective available potential energy generally in the 500-1500 j/kg range).
Also...forced lift will be weak...owing to a lack of dynamic
forcing in the middle to upr-lvls. Thus...we expect diurnal
convection to be isolated in nature...and mainly confined to the
higher terrain of the Poconos and western Catskills. Whatever storms
do form...however...may be very efficient rain producers with slow
forward motion...given precipitable waters increasing into the 1.5-1.75"
range...and middle-level shear quite weak above a developing ll-jet around 900
mb early this evening.
Short term /6 PM this evening through Thursday night/...
430 am Tuesday update... after any isolated thunderstorms across our southeastern zones
through 02-03z...most of the remainder of the night should be quiet.
Towards daybreak (07-10z)...we may see some addtnl showers/thunderstorms try to
sneak into our northern and western zones...associated with a lead shortwave...and
well ahead of an approaching cold front. We'll use chance/scattered probability of precipitation to
cover this for the time being.
On Wednesday...we should see better convective coverage by midday/early
afternoon...with New York/PA residing within a developing upper jet entrance region...a
well defined surface cold front pushing into western/central New York...and some
height falls aloft. Probability of precipitation will thus increase into the likely/numerous
Despite decent prognosticated instability (ml convective available potential energy generally 1000-2000 j/kg
)...deep-lyrd shear looks marginal (0-3 and 0-6 km bulk shear
vectors mainly 20-25 kt). Thus...the actual severe threat may be
somewhat limited...with locally heavy rainfall perhaps the greater
threat given precipitable water values 1... mbe vectors at or below 10 knots...and
warm cloud depths of 11k+ feet. Running the above described parameters
through our severe weather checklist yields mainly events with short/broken
linear Mode...with isolated high wind reports and localized flooding. I
feel there's enough there to add a mention of locally heavy rain and
gusty winds in the severe weather potential statement for Wednesday.
The main surface cold front is expected to progress through our entire
County Warning Area by Wednesday evening...with convection diminishing by this time. We'll
carry lingering chance/scattered probability of precipitation early Wednesday night...mostly for the southeastern
half of the forecast area.
Thursday looks like a nice middle-Summer day...with a fair amount of
sunshine...lower humidity levels...and afternoon highs ranging mostly in
Long term /Friday through Monday/...
high pressure will build in behind a departing cold front by early
Friday morning. Generally fair weather is then expected to cover a
few days into the first half of the weekend...then the complexity
of a changing upper level pattern takes over. A large...building
ridge of high pressure over the Desert Southwest will allow a high
amplitude trough to enhance across the eastern half of the nation
from Sunday into the middle of next week. The generalities of this
pattern suggest a cooler than normal (meaning 70s versus 80s) and
relatively wet period of weather with a chance of showers and
thunderstorms starting Saturday night and lasting at least through
Monday. The medium range models still have considerable disagreement
in the details of the exact placement of the trough along with
individual waves of low pressure and frontal positioning during
this period. It is therefore not prudent to try and pin down
whether or not rainfall will be more dominant at night, or during
the day. Generally... playing the daytime card due to increasing
instability factors is the better bet...but the variability is so
high that a Standard middle ground of chance probability of precipitation will have to
Aviation /08z Tuesday through Saturday/...
River Valley fog potential has decreased this morning because of a
persistent broken middle deck. The best chance for IFR fog will be at
kelm between 9z and 12z. Brief MVFR conditions may develop at
VFR conditions and southwest winds of 5 to 10 knots are forecast
for today. Will watch for fog potential again Wednesday morning,
but clouds ahead of next system may decrease the coverage.
Wed/Thu...a cold front approaches the region with associated
restrictions due to shra/tsra. Front clears the region by late