Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Albany New York
446 PM EDT Thursday Jul 10 2014

Synopsis...
high pressure will continue to build into the region today while a
frontal boundary remains nearly stationary to the south. Expect dry
and comfortable weather through Friday. Moisture will begin to
return to the region on Saturday...leading to a good chance for
showers on Sunday as a disturbance moves across New York and New
England.

&&

Near term /until 6 am Friday morning/...
as of 400pm...high clouds continue to stream northeastward across
the southern parts of the region and along the high terrain of
eastern New York and western New England. Our region still sits north of a
frontal boundary where it is now well south of the region near Long
Island New York. High clouds will slowly begin to move south and
east out of the region as we go into the overnight hours with mostly
clear to partly cloudy skies. Low temperatures with light winds and
clearing skies with radiational cooling this evening will range from
middle 40s in parts of the Adirondacks to middle and upper 50s for the
rest of the region.

&&

Short term /6 am Friday morning through Saturday night/...
as we go into the day on Friday...latest 12z model and numerical
guidance shows another tranquil weather day in store. Our region will
be under an area of high pressure and being positioned upstream of a
low amplitude trough axis will provide additional surface divergence
in the region. As a result...skies will be mostly clear..especially
the further north and west from the immediate capital region with
the exception of still a few high clouds in the farthest southern
areas with the stalled out front well into the Atlantic. Local WRF
and other hi res model runs show precipitation continuing to ignite
along the baroclinic boundary well south of the region with daytime
heating...but with synoptic conditions aloft negating any vertical
ascent...fair weather is expected with high temperature ranging from
the lower 80s in the high terrain to middle and even a few upper 80s in
valley locations especially in the middle Hudson Valley. Humidity will
also be at comfortable levels with dewpoint temperatures in the middle
to upper 50s.

As we approach Friday evening into the overnight hours...a more
zonal synoptic flow with a surface high pressure in place near our
region will continue to bring tranquil weather to the region. As
previously discussed...high pressure with synoptic conditions
showing descent in the atmosphere will favor fair weather conditions
during the Friday evening hours. Low temperatures will moderate
slightly from Thursday night with values ranging from the upper 40s
in the high terrain of the Adirondacks to mid50s for the erst of the
region.

Going into the first half of the weekend on Saturday...newest 12z
global models have retreated the precipitation for our western zones
which was present in the previous run. Upper level zonal flow with
weak ridging that is being held up by the stalled frontal system
accompanied by weak winds above 500 hpa slowing down forward
propagation...will allow the region to see another tranquil weather
day coming up for the entire region. Winds around the departing high
pressure with its center near the East Coast will allow
southwesterly flow to return to the region which will allow high
temperatures on Saturday to range from the upper 70s in the highest
peaks to middle and upper 80s...especially for the middle Hudson Valley.

Going into Saturday night...cloud cover will begin to increase from
the west ahead of our next weather system with areas of
precipitation well off to the west over the Great Lakes as seen by
the latest 12z European model (ecmwf)/GFS and global probabilistic quantitative precipitation forecast models. A
elongated frontal boundary stretching from southern Canada west into
the plains will slowly progress eastward throughout the night. Model
700-500 hpa relative humidity layers indicate middle and high level clouds moving in
ahead of our next weather system. This will allow temperatures to be
warmer than previous nights. In conjunction with 850 hpa warm air advection that
will advect temperatures of 14c to 17c back into the
region...temperatures will be rather warm Saturday night with low
temperatures ranging from the upper 50s in the highest terrain to
low and middle 60s for the rest of the region.

&&

Long term /Sunday through Thursday/...
the long term forecast looks to be very active. Latest 12z global
models and numerical guidance shows favorable agreement in an active
pattern associated with a closed off upper level low progressing slowly
along southern Ontario that will provide several days of on and
off unsettled weather.

Sunday into Monday....a warm front will begin to move northeast into
the region associated with a weak surface low along a baroclinic
boundary extending westward into the Midwest from a surface low near
Lake Erie. As we progress into the day on Monday...the warm front
will be well north of the region as our entire region sits in the
warm sector. Some global probabilistic models show a perturbation in
the 500 hpa flow as we go into the day on Monday. With daytime
heating in conjunction with high dewpoints into the middle and upper
60s along with mesoscale boundaries in 850-500 hpa 6c/km lapse
rates...there is a chance of some convection initiating as we go
into Sunday afternoon with a better set up looking to be on Monday
afternoon. This will be modified as the forecast is updated. High
temperatures on Sunday and Monday will range from the upper 70s to
middle 80s.

Tuesday into Thursday...as the upper level low over southern
Ontario moves to the east near the western shoreline of Lake
Ontario...the atmosphere over our region will be tapping into more
favorable synoptic conditions for thunderstorm development. A
progressing cold front extending from a weak surface low downstream
of an upper level voriticty maximum will set the base for active
weather as we go into Tuesday afternoon. Working with the surface
features...our region will be in the right entrance region of a
powerful 100 to 120 knots as the latest models indicate. Along with
acceptable middle and low level lapse rates and a 850-700 hpa 40 knots
jet...ingredients may come together with diurnal heating for a high
probable thunderstorm development. With t850 near -10c as well with
established updrafts from thunderstorms...hailstones may accompany
these storms as well. The cold front will progress westward across
our region and should be out of the region during the overnight hours
Tuesday into Wednesday. High temperatures on Tuesday will range from the middle 70s to
lower 80s. After the front GOES through for the day on
Wednesday...temperatures will be below average with highs ranging
from the upper 60s to middle 70s. Leftover showers from the departing
upper level system will linger into Wednesday evening but otherwise
a nice day is set up for Thursday with highs on Thursday ranging
from the lower to middle 70s.

&&

Aviation /21z Thursday through Tuesday/...
VFR conditions will prevail throughout the taf period as high
pressure builds across the region.

This afternoon...except for a few cumulus around 5 kft and scattered
high clouds...little in the way of cloud cover throughout the
afternoon as high pressure builds across the region. Winds will be
light and variable generally less than 5 knots.

Tonight into Friday...VFR conditions will continue throughout the
night with little if any fog expected to develop. While patchy fog
cannot be ruled out...especially at kgfl and kpsf...confidence is
too low to include in the tafs at this time. High level clouds will
gradually dissipate throughout the night leaving clear skies to end
the taf period Friday.

Winds will trend towards calm tonight before becoming light and
variable less than 5 knots Friday.

Outlook...

Friday night and saturday: no operational impact. No sig weather.
Saturday night: low operational impact. Slight chance of rain showers...tsra.
Sunday and Sunday night: moderate operational impact. Scattered rain showers...tsra.
Monday and tuesday: moderate operational impact. Chance of rain showers...tsra.

&&

Fire weather...
the recent wet weather will keep fire weather concerns rather low
despite a period of mainly dry weather expected in the forecast for
the next few days. With more wet weather expected...fire concerns
will continue to be at a minimum. Min relative humidity values today will generally
range between 35 and 45 percent with a light wind.

Light winds and still some residual low level moisture will result
in a recovery of relative humidity values at or above 90 percent tonight.

There will still be some moisture in the lower levels through
Friday to keep minimum relative humidity values between 40 and 50 percent.

&&

Hydrology...
no widespread Hydro problems are anticipated the next few days across
the Hydro service area.

Generally...dry conditions are expected through at least early
Saturday. Another disturbance will bring some scattered showers
and thunderstorms for the 2nd half of the weekend into Monday with
rainfall amounts in the tenth to half an inch range with locally
higher amounts especially in our western areas.

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...lfm
near term...lfm
short term...lfm
long term...lfm
aviation...irl
fire weather...lfm
hydrology...lfm

National Weather Service Glossary of Abbreviations