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Area forecast discussion 
National Weather Service Albany New York
650 am EDT Tuesday Oct 21 2014

Synopsis...
a complex weather disturbance will organize in the Great Lakes
tonight. It will intensify as it moves to the middle Atlantic coast by
Wednesday...and then northeast to the New England coast by Thursday.
A long period of unsettled weather and intermittent rain is expected
from tonight through Thursday night or Friday...with the steadiest
rain expected Wednesday night into Thursday.

&&

Near term /until 6 PM this evening/...
except for some adjustments to the hourly temperature grids in order to
reflect current conditions...no changes made to the previous
forecast.

Previous discussion...
the upper level trough will be in the process developing into a
closed upper low today as it moves towards the central Appalachians.
For today the flow across the region will be south to southwest
ahead of this system. Radar pics as of 430 am show enough precipitation
coverage to warrant increasing probability of precipitation to likely in all areas
today...and to categorical levels over the western half of the
region. Highs today will be in the 50s to lower 60s.

&&

Short term /6 PM this evening through Thursday/...
the upper low will continue to slide east tonight and Wednesday with
a surface low also developing off the middle Atlantic coast. As this
evolution takes place...there will be a drop off in precipitation activity
tonight and have forecast mainly chance probability of precipitation for most of the night.

As the low pressure system moves further out to sea...the forecast
area will get into the warm conveyor band of precipitation as Atlantic
moisture surges westward on the northern side of the upper low. As a
result...precipitation will become more widespread again during Wednesday and
continue into Wednesday night. Have raised probability of precipitation to categorical by
later Wednesday across the entire region and continue to forecast
categorical probability of precipitation Wednesday night.

As the low pressure system moves into the Gulf of Maine on
Thursday...have lowered probability of precipitation to likely across the southwest half of
the forecast area...but categorical probability of precipitation continue over the northeast
half.

Lows Tuesday and Wednesday nights will be in the 40s. Highs
Wednesday and Thursday will generally be in the upper 40s to middle
50s.

&&

Long term /Thursday night through Monday/...
the period starts out on Thursday night with a vertically stacked
low still centered in the vicinity of Cape Cod...with a sprawling
cyclonic northerly flow continuing to bring some showers to the
region. The best chance will be north of the capital district where
likely probability of precipitation are mentioned. Models in agreement that this low
pressure system will finally start to pull eastward and out to sea
on Friday. However...our region will still be under a cyclonic flow
regime so some lingering showers are possible. It will continue to
be cool and damp...with overcast skies resulting in not much
potential for warming.

Chances for showers will decrease further Friday night although a
few showers cannot be ruled out for areas north and west of Albany
as the flow turns more westerly. There is uncertainty with regards
to the weekend forecast...as the main question is how far south an
upper level trough approaching from southern Canada digs over the
northeast Continental U.S.. the GFS is the most optimistic in terms of keeping
the brunt of the trough north of the region with mild temperatures.
However...the European model (ecmwf) and the CMC to an extent...depicts the trough
digging farther south and allowing for colder air to work into the
region with some mountain showers possible in a developing cyclonic
flow regime.

So bottom line is that the weekend has the potential for warmer than
normal temperatures and more in the way of sunshine...or cooler temperatures and
more clouds. We will have to see which way the models trend as the
weekend nears.

&&

Aviation /12z Tuesday through Saturday/...
occasional showers will continue to impact the terminals today...as
an upper level disturbance moves across the area. Unsettled
conditions will persist through the rest of the day and into this
evening...as a broad upper level low will become established
across the region. Will mention prevailing showers through much of
the period...although it will not be raining the entire time as
batches of showers will periodically move through.

Flying conditions expected to remain in VFR range through much of
today...with ceilings only gradually decreasing. By this evening there
will be a better chance for MVFR conditions at the terminals with
occasional showers continuing.

Winds will be light and variable...becoming north-northeast around 5
kts by this afternoon.

Outlook...

Wednesday night: high operational impact. Definite rain.
Thursday: high operational impact. Likely rain.
Thursday night: moderate operational impact. Chance of rain showers.
Friday: moderate operational impact. Chance of rain showers.
Friday night: low operational impact. Slight chance of rain showers.
Saturday: no operational impact. No sig weather.

&&

Fire weather...
a complex weather disturbance will organize in the Great Lakes
tonight. It will intensify as it moves to the middle Atlantic coast by
Wednesday...and then northeast to the New England coast by Thursday.
A long period of unsettled weather and intermittent rain is expected
from tonight through Thursday night or Friday...with the steadiest
rain expected Wednesday night into Thursday.

&&

Hydrology...
no hydrologic issues expected through the end of the week...even
though weather is expected to turn unsettled and wet as an upper
level low cuts off south and east the region. Intermittent rainfall
is expected from today into Friday...with the steadiest and heaviest
rainfall expected for late Wednesday into early Thursday.

With the periods of rainfall...some moderate to heavy bursts may
occur...especially late Wednesday into early Thursday. The potential exists for one to
two inches of rainfall over portions of the Hydro service area
depending on this systems evolution...and track. This rainfall
would occur over the period of a few days...so no widespread
flooding is anticipated at this time. At this time...it appears
that the greatest amts would be favored across higher elevations
of western New England...especially southern Vermont...and possibly the
eastern Catskills...with less amts occurring within the Hudson
River valley due to downsloping.

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 website.

&&

Aly watches/warnings/advisories...
CT...none.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...gjm
near term...gjm
short term...gjm
long term...jpv
aviation...jpv
fire weather...kl/gjm
hydrology...kl/gjm

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