Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
416 am EDT Monday Jul 6 2015
along with a partly to mostly sunny sky...warm
temperatures will be in place over the region today with increasing
levels of humidity. An upper level disturbance will allow for the
chance of a shower or thunderstorm tonight into tomorrow...with warm
and muggy conditions continuing. A passing cold front will continue
the threat for a shower or thunderstorm on Wednesday...before drier
and less humid air works into the area for late in the week.
Near term /until 6 PM this evening/...
as of 416 am EDT...a weak upper level disturbance is situated
between the Ohio River valley and Middle Atlantic States...with
ridging extending along the eastern Seaboard and into New England.
At the surface...weak high pressure over the area is starting to
slide eastward...while a stalled front over the southeast is
starting to lift north as a warm front.
Convection over the Middle Atlantic States associated with the upper
level disturbance is allowing some high level clouds to stream
into our region from the south. Through the day today...there will
be periods of thin high clouds...otherwise...skies will be mostly
sunny. The nearby high pressure and lack of large scale forcing will
keep it rain free today.
With warm air advection in place...850 hpa temperatures look to
rise to around 15 degrees c...allowing for high temperatures well into
the 80s in most areas. A light southerly flow at the surface will
continue to advect low level moisture into the area...so it will
start to feel muggy by this afternoon...with dewpoints reaching into
Short term /6 PM this evening through Wednesday/...
the upper level disturbance will start to get sheared out as it
lifts northeast into the ridge in place. Still...there may be
enough lift to allow for a light rain shower late tonight...especially
for southern and western areas. Otherwise...clouds will start to
increase with lows in the 60s. It will continue to feel rather
The combination of the weak upper level disturbance overhead and
pre-frontal surface trough ahead of a cold front over the Great Lakes
will allow some showers and thunderstorms to develop on Tuesday
within daytime heating. It/S unclear just how much instability
will be in place as there may be a lot of clouds around...but
cape values will be aided by the high dewpoints in place. With
precipitable waters 1.50 to 2.00 inches...any thunderstorm will be capable of
producing locally heavy downpours. 0-6 km shear is fairly
low...just 20-25 kts...and lapse rates will be fairly low as
well...so it will be tough for storms to become quite organized.
Storm Prediction Center doesn/T have our region in any outlook for severe weather...so
the main threat on Tuesday will be the locally heavy downpours. Temperatures
look to reach into low to middle 80s for valley areas...although this
will depend on how much cloud cover is present. Best chance for
seeing showers/thunderstorms may be across southern and eastern
There may be a lull in shower and thunderstorm activity on Tuesday
night due to the loss of daytime heating...but will keep slight to
low chance probability of precipitation in the forecast. It will remain mild and muggy
overnight...with lows near 70 in valley areas.
The cold front will be crossing the region during the day on
Wednesday. Exact timing is still uncertain...but it could be
crossing the County Warning Area between the early to middle afternoon hours. Some
shower/thunderstorm activity looks to accompany the frontal
passage. Instability/shear parameters Don/T look impressive for
any strong/severe storms once again...but precipitable waters remain high...so
cannot rule out some heavy downpours with any shower or
thunderstorm...especially for southern areas where model guidance suggest
precipitable waters could exceed 2.00 inches. With the threat for locally heavy
downpours...will include mention of heavy rain within any
thunderstorm in the severe weather potential statement at this time.
Temperatures on Wednesday will be warmest in southern/eastern areas where
the front will cross later in the day. Maximum temperatures range from the
middle 70s to middle 80s across the region.
Long term /Wednesday night through Sunday/...
most of the long term portion of this forecast appears to be rather
dry and tranquil with near seasonable Summer temperatures.
We begin this long term portion of the forecast with the departing
cold front with a near zonal flow across the northeast. As this
front slides toward the i80 corridor...it will become nearly
parallel to the upper flow as global models suggest a potential for
a couple of waves to develop along the boundary and may impact our
southern portions of the region Thursday into Thursday night. For
now...nothing more than slight chance probability of precipitation with an increase in cloud
coverage for the region.
What wave/S/ do track and impact the region will depart by the end
of the week with improving conditions. Global models differ
somewhat with respect to the evolving synoptic flow pattern regime
late in the week and into the weekend. The European model (ecmwf) wants to amplify
the upper trough across the northeast with the GFS/ggem much less
pronounced. This will have some implications with respect to
diurnal driven cumulus and temperatures. For now...followed the ensemble
mean values with dry conditions and close to seasonable
Aviation /08z Monday through Friday/...
challenging near term aviation forecast as dewpoint depressions
were rather narrow...yet satellite imagery along with surface observation
reveal a canopy of high and middle level clouds across the region.
This is placing a complex forecast for flight conditions overnight with
respect to IFR or not. Cross sections and BUFKIT profiles point
toward a more cloud coverage which would reduce the probabilities
for IFR conditions. For now...we will lower into tempo groups for
kgfl-kpsf with IFR conditions with tempo MVFR conditions for
kalb-kpou. Any fog will burn off within a few hours after
sunrise...with VFR conditions then prevailing through 06z
Winds will be light and variable overnight...becoming southerly
around 3-7 kts by Monday afternoon.
Tuesday night: moderate operational impact. Chance of rain showers...tsra.
Wednesday: moderate operational impact. Likely rain showers...tsra.
Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
Thursday night: no operational impact. No sig weather.
Friday: no operational impact. No sig weather.
Friday night: no operational impact. No sig weather.
Saturday: no operational impact. No sig weather.
fire weather concerns remain low at this time.
Dry weather is expected today with a partly to mostly sunny sky.
Relative humidity values will fall to around 40 percent this afternoon...with light
south winds of 5-10 kts. Some showers and thunderstorms will be
around on both Tuesday and Wednesday with relative humidity values only falling
to 55 to 65 percent each afternoon.
dry weather is expected today...however...an upper level
disturbance will return the chance for showers and thunderstorms
for late tonight into tomorrow. Any thunderstorm on Tuesday will
be capable of producing locally heavy downpours...but widespread
heavy rainfall isn/T expected over the region. While some rises on
small streams cannot be ruled out over any small basins that see
thunderstorm activity on Tuesday...most larger Stem rivers will
mainly stay steady or only see minor rises.
Some additional showers and thunderstorms are possible Tuesday
night into Wednesday. There will continue to be a threat for
locally heavy rainfall in areas that see thunderstorms...but
widespread problems aren/T anticipated at this time. Mainly dry
weather will return for Thursday and Friday.
For details on specific area rivers and lakes...including observed
and forecast river stages and lake elevations...please visit the
advanced hydrologic prediction service /ahps/ graphs on our