Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
954 am EDT Tuesday Jul 7 2015
with a muggy air mass in place...an upper level
disturbance will allow for some showers and thunderstorms
today...some of which may contain heavy downpours. A passing cold
front will continue the threat for a shower or thunderstorm tonight
into tomorrow. Although there still may be a lingering shower around
for Thursday...mainly drier and less humid conditions will return
for the remainder of the week.
Near term /until 6 PM this evening/...
as of 950 am EDT...clouds have finally filled in across much of
the area...outside of some lingering breaks across portions of
the upper Hudson River valley and SW Vermont. Spotty showers were
moving into portions of the eastern Mohawk Valley and northwest
portions of the capital region...extending south into the eastern
Catskills...although recent trends have been for the areal
coverage to decrease slightly over the past hour. Additional
showers are developing across portions of southern Litchfield Colorado
CT...and off to the west across central New York state and PA.
Latest WV imagery depicts an upper level disturbance located
over west central PA and is heading northeast towards the area.
Visible satellite imagery shows clouds continue to expand across the
Daytime heating and the nearby approaching disturbance will allow
showers to have a somewhat greater areal coverage towards
midday...as suggested by the latest 3km hrrr and nam12 guidance.
With dewpoints in the upper 60s to near 70...precipitable water values will
climb to around 1.75-2.00 inches across the entire region. These
values are close to 2 Standard above normal. Because of this...can
expect any shower/thunderstorm to be capable of rather heavy
downpours. The chance for strong/severe thunderstorms is quite low
for today due to limited instability with the periods of cloud
cover...and weak 0-6 km bulk shear values less than 25 kts.
Skies today look to mostly cloudy through at least midday...before
some breaks in the clouds potentially develop from west to east during
the middle to late afternoon. Maximum temperatures today will depend on just
how many breaks of sun can occur...but there should be enough to
get valley areas into the low to middle 80s...with 70s for the higher
elevations by late afternoon.
Short term /6 PM this evening through Thursday/...
although the weak upper level disturbance will be moving away this
evening...the threat for showers and thunderstorms will remain in
the forecast for tonight...as another storm system approaches
from the Great Lakes. Ahead of this storm/S surface cold front...it
will remain mild and muggy with dewpoints in the upper 60s to 70...and
temperatures only falling into the upper 60s to low 70s for lows in many
places as well.
A band of showers and thunderstorms looks to accompany this front
as it crosses the region. Surface-based instability will be limited
tonight due to the time of day...but there could be a rumble of
thunder tonight in a few spots. The front will be crossing the
northwestern parts of the region by late tonight...and looks to
pass the remainder of the region during the morning or very early
afternoon on Wednesday. Again...instability appears limited so not
everywhere will see thunder...but with dewpoints/precipitable waters remaining
high...the threat for heavy downpours in a short period of time
will remain in place until the front crosses the area.
Maximum temperatures on Wednesday will depend on location relative to the
front...with northwestern areas only rising into the low to middle
70s...while southeastern areas look to reach the middle 80s. The
capital region should reach right around 80...with decreasing
humidity levels behind the front in the afternoon hours.
Most areas look dry for Wednesday night. The exception may be far
southeastern areas...where the front may stall close to the area.
Lows will fall into the middle 50s to middle 60s...although some 40s
will be possible in the Adirondacks.
The frontal boundary will be stalled just south of the area...and
a wave of low pressure looks to slide along this boundary for
Thursday. Although the bulk of the activity with this feature will
be south of the region...cannot totally rule out a few additional
showers on Thursday for the southern half of the region. Will keep
chance probability of precipitation in the forecast for these areas. Temperatures will only reach
the 70s across the area...with the warmest temperatures across northern
areas where the most sun and less chance for precipitation will occur.
Long term /Thursday night through Monday/...
latest global model consensus favors subtle changes to the overall
pattern with a weak/broad trough over the northeast as the upstream
ridge breaks down and is replaced with a deeper more vigorous trough.
Thursday night the front will continue to slowly settle southward
with linger affects south of i90 early on where we will retain the
slight chance probability of precipitation. Overnight...conditions should improve with
drier conditions advecting in from the northwest.
A narrow ridge settles across the region for the end of the week and
should hold on through at least the first half of the weekend.
While humidity levels should be near climatology...temperatures
should average near to above normal to result in a rather nice
summerlike start to the weekend.
The next potential for unsettled weather looks to be from Sunday
into early next week...as multiple disturbances interact with
approaching frontal boundaries. Details remain very difficult to
forecast this far out...with models showing a wide range of
solutions for timing/placement of potential convection although
trends were slowly favoring a little drier weather pattern for
Sunday. The previous forecast approach remains the same for now as
to broadbrush slight chance to chance probability of precipitation and refine further as we
get closer in time. Humidity levels and cloud coverage will be on
the rise along with the increasing threat for showers and
Aviation /14z Tuesday through Saturday/...
scattered-broken MVFR stratus deck was across most of the region this morning as
the main shower area was west of the Hudson River. Expectations today
are for the ceilings to remain within MVFR/VFR border thresholds as
showers/storms develop within the increasing warm and moist air mass.
Per the hrrr...there appears to be somewhat deeper convection as we
will include a prob30 for convection at all taf sites later this
Tonight...there may be a lull in the activity as we await for the
approaching cold front. This will likely bring additional showers
overnight as we will place a tempo group at this time.
Winds will be southerly less than 10kts through the forecast period.
Wednesday night: moderate operational impact. Slight chance of rain showers.
Thursday: moderate operational impact. Chance of rain showers.
Thursday night through saturday: no operational impact. No sig
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 drop
to 40-60 percent on Wednesday afternoon. 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 today...most
larger Stem rivers will mainly stay steady or only see minor
rises. If a heavy shower/thunderstorm occurs over an urbanized
area...cannot totally rule some minor street/poor drainage
flooding occurring today.
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