Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
127 am EDT Tuesday Jul 7 2015
an approaching warm front from the south...along with an upper
level disturbance will allow for the chance of a shower or
thunderstorm tonight into tomorrow...along with warm and muggy
conditions. A passing cold front will continue the threat for a
shower or thunderstorm Tuesday night into a portion Wednesday.
Slightly cooler and less humid conditions will arrive later in the
Near term /until 6 am this morning/...
as of 127 am EDT...an upper level disturbance is located
southwest of the region over western PA and is heading northeast
towards our area.
Infrared satellite imagery shows mainly clear skies continue over the
majority of the region...except the southern and eastern ...
some low stratus clouds are starting to build northward into the
Catskills...middle Hudson Valley...northwest CT and Berkshires. These clouds
will gradually build northward through the remainder of the
overnight hours...although it may take until daybreak for clouds
to build into the Adirondacks and Lake George Saratoga region.
Most of the overnight hours will be dry...although a shower or two
cannot be ruled out towards daybreak over the Catskills...as the
upper level disturbance starts to approach the area. The 3km hrrr
seems to suggest the best chance for any showers will wait until
later in the day on Tuesday.
Min temperatures overnight will mainly be in the 60s to near 70...although
some 50s will occur over the Adirondacks where skies will be clear
the longest. It will continue to feel muggy....as the southerly
low level flow will allow dewpoints to continue to rise into the
Short term /6 am this morning through Wednesday night/...
Tuesday...as the aforementioned upper level disturbance passes across
the region between late morning and middle afternoon...showers
should increase in areal coverage during the morning hours. Have
indicated chance probability of precipitation...for scattered showers/isolated thunderstorms
for most areas...except for likely/numerous showers from around
the capital region east into western Massachusetts/SW Vermont...where a local maximum
of shower coverage is expected based on the passage of the
embedded upper level shortwave...and also greater proximity to low
level moisture. As precipitable water/S increase above 1.50 inches...some
locally heavy downpours will be possible. As for thunder
chances...it appears that widespread clouds and weak middle level
lapse rates should minimize the threat for thunder through at
least early afternoon. Then...as the shortwave trough axis moves
across and east of the region later in the day...some breaks of
sun will likely develop from west to east and result in some
destabilization...but we also may have a period of middle level
subsidence to counterbalance this increased instability.
So...chances for afternoon convection are quite nebulous. For
now...have included mention of isolated thunder in the
afternoon...but if some breaks in the clouds develop sooner...then
a slightly better chance of convection will be possible.
Also...toward sunset...with a cold front approaching from the
northwest...thunderstorms may become more likely across far northern
Herkimer Colorado by or after sunset. Maximum temperatures should reach the
Lower/Middle 80s in valleys...and upper 70s/lower 80s across higher
terrain...assuming some breaks of sun develop later in the
afternoon. However...if low clouds persist longer...much of the
region may only reach the 70s. It will be quite
humid...however...as dewpoints rise into the middle 60s to lower
Tuesday night...a cold front should approach from the Great Lakes
region. Lingering instability may result in some showers and
thunderstorms in the evening hours across the western/southern
Adirondacks and perhaps western Mohawk Valley. This may be in the
form of clusters and/or small line segments...and will have to be
watched for locally gusty winds as the middle level wind field
strengthens. Showers/thunderstorms should then gradually decrease
in areal coverage and intensity later in the evening...as the best
upper level support lifts north of the region...and low level
instability wanes. Will keep chance probability of precipitation for scattered
showers/isolated thunderstorms for later at night...with the best
chance for areas from the capital region and points north and west. It
should be warm and humid...with min temperatures only falling into the
middle 60s to around 70.
Wednesday...the cold front should already be settling southeast across
the western Mohawk Valley/southern Adirondacks around daybreak. It
should then continue heading south and east...passing the capital
region during the late morning/midday hours...and then into
western Massachusetts/northwest CT and the middle Hudson Valley/southeast Catskills during the
early to middle afternoon. Areas S and east of Albany will have a
slightly greater chance for destabilization ahead of the
front...and therefore best chance for scattered convection.
Further north and west...although a few additional showers with the front
can/T be ruled out...the chances for thunder should be much less.
Afternoon temperatures should generally reach the middle 70s to around
80...except into the Lower/Middle 80s across the middle Hudson Valley
and lower elevations across SW Massachusetts/northwest CT.
Wednesday nt...turning cooler and less humid. However...some clouds may
persist and/or increase later at night...especially for areas south of
Interstate 90...as the front slows down in response to an
approaching upper level impulse from the west. Min temperatures should
fall into the 50s to lower 60s.
Long term /Thursday through Monday/...
the period starts out on Thursday with a frontal boundary positioned
just south of our area...with some sources of guidance including the
NAM/GFS showing a short wave trough moving into the region during
the afternoon/evening. However...the European model (ecmwf)/CMC indicating a weaker
disturbance moving generally south of the region. So will only
mention low chance probability of precipitation for now due to uncertainty. Thursday will be
a cooler day behind Wednesday/S cold front though...with highs
expected to be in the 70s region-wide.
Despite the differences in the models for Thursday...the Friday
through Saturday period looks very consistent with a ridge of high
pressure dominating the weather during this time. Temperatures look
to be very close to normal for early-middle July with humidity levels
fairly comfortable due to a northwest flow regime.
The next potential for unsettled weather looks to be from Sunday
into early next week...as multiple disturbances interact with an
approaching frontal boundary. Details very difficult to forecast
this far out...with models showing a wide range of solutions for
timing/placement of potential convection. Approach for now is to
broadbrush chance probability of precipitation and refine as we get closer in time. Humidity
levels will be on the rise along with the increasing threat for
showers and thunderstorms.
Aviation /06z Tuesday through Saturday/...
enhanced satellite fog imagery /11u-3.9u/ reveals the MVFR stratus
deck was advecting northward across the middle Hudson Valley and into
the Berkshires where MVFR conditions will be present for kpou-kpsf.
This deck will eventually spread northward into kalb soon then into
kgfl later overnight. Should remain dry overnight with either a
light and variable wind or a light southerly breeze.
During the daylight hours...ceilings will remain within MVFR or just go
above into VFR. However...per the hrrr reflectivity
forecasts...seems the showers across eastern PA may impact the taf
locations through the morning and into the early-middle afternoon
hours. The showers may dissipate for a period of time into this
evening before the cold front approaches overnight with more showers.
As for thunder potential...it does exist from late this morning into
tonight. However...confidence to place in the taf this far out
remains low to warrant mention in the tafs.
Tuesday night: moderate operational impact. Chance of rain showers...tsra.
Wednesday: moderate operational impact. Scattered rain showers...tsra.
Wednesday night: low operational impact. No sig weather.
Thursday: moderate operational impact. Chance of rain showers...tsra.
Thursday night: low operational impact. Slight chance of rain showers...tsra.
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.
An upper level disturbance will allow for some showers and
thunderstorms today. Additional showers and thunderstorms are
possible tonight into tomorrow with the passage of a cold front.
Relative humidity values will only fall to around 60 percent this afternoon...and only
drop to 50-60 percent on Wednesday afternoon as well. Southerly
winds will be around 10-15 miles per hour today...and will switch to the
northwest behind a cold front on Wednesday afternoon at 5 to 10
miles per hour.
an upper level disturbance will allow for some showers and
thunderstorms today. With precipitable waters climbing above 1.75 inches...any
thunderstorm today 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
Some additional showers and thunderstorms are possible tonight
into tomorrow with an approaching cold front. With high precipitable waters
still in place...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. Although some additional
light rain showers are possible thanks to a nearby frontal
boundary for Thursday for southern areas...mainly dry weather
looks to return for Friday and Saturday.
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