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Area forecast discussion 
National Weather Service Albany New York
136 am EDT Monday Jul 28 2014

Synopsis...
a low pressure system will continue to strengthen and move eastward
across the region through Monday accompanied by showers and
scattered thunderstorms. The system will move off to our northeast
Monday night allowing cooler air to filter into the region. High
pressure will build in at the surface as we head through middle
week...however aloft disturbances will pass over the region.

&&

Near term /until 6 am this morning/...
east-West Line of convective with heavy rain has blossomed across
western and central New York with the activity extending into the
Mohawk Valley in the vicinity of a surface warm front. Potent
short wave moving across the Great Lakes is resulting in rapid
deepening of the surface low over the region. Instability values
have decreased across most of the forecast...with the southern
most portion with cape values up to around 1000 j/kg. However...the
upper jet dynamics are coming into play and are enhancing the
vertical lift over the region aiding the developing of the storms
in the moisture rich airmass across New York state. The strong
upward vertical motion and height falls will increase late
tonight/early Monday morning.

The 3-km hrrr continues to adjust for the placement of on-going
convection and has it expanding and moving northward across the
area through the early morning hours. Have kept mention heavy
rainfall in forecast. The enhanced wording for the gusty winds
and small hail now begins at 6 am.

The low level shear/helicity and other forecast model calculated
severe/tornado parameters will continue to be monitored this morning
with the well defined surface low pressure tracking through the region
towards. Lows will be in the 60s to near 70.

&&

Short term /6 am this morning through Wednesday/...
the upper impulse and associated low level forcing pivots north
and northeast through the day...with strong convection
transitioning to showers with locally heavy rain as the comma head
precipitation trails the leading convection. Keeping the gusty
winds and heavy rain associated with convection tomorrow...then
coverage of rain should decrease through the afternoon...with the
southern Adirondacks...Lake George Saratoga region and southern Vermont
to the northern Berkshires seeing the rain end more toward
evening. Highs Monday in the 60s to lower 70s...but could be a
little warmer if there are gaps between clusters of showers and
thunderstorms. Southern areas could be in the middle to upper
70s depending on how much of the warm sector tracks through
southern areas through midday. Winds are expected to shift to
west and may be gusty when the cold front tracks through during
the afternoon and evening.

Some gradual clearing takes place through the night and winds
should diminish. Tuesday and Wednesday look mainly dry as a cooler
and dryer airmass spreads across the region. The mean upper trough
axis is still a bit west of our region...so there could be some
intervals of middle and high clouds but again...the weather should be
dry. Highs Tuesday in the middle to upper 70s...cooler in the
southern Adirondacks. On Wednesday...highs in the upper 70s to
lower 80s...but lower to middle 70s higher elevations. The leading
edge of some scattered showers could approach western areas
Wednesday afternoon with the approach of another upper impulse.

&&

Long term /Wednesday night through Sunday/...
a mean longwave trough will continue to impact the northeast from
the midweek into next weekend. The long term forecast will
feature some disturbances rotating through the upper trough until
the end of work week...but then high pressure over the north-central
Atlantic builds westward with the upper level flow becoming more
southerly late in the weekend...as a frontal boundary remains near
the Atlantic Seaboard for next weekend.

Wednesday night into Thursday...high pressure will be ridging in
from the Ohio Valley...and the middle Atlantic region. A short-wave
rotating around the upper level trough may focus some isolated-scattered
showers late Wednesday night...especially west of the Hudson River
valley. The surface trough associated with this feature may focus some
scattered showers and isolated thunderstorms during the afternoon on Thursday.
The GFS indicates more synoptic forcing from the differential
cyclonic vorticity advection than the European model (ecmwf) this run. The better
forcing looks like from the capital region northward...so chance probability of precipitation
were used here...with slight chance further south. H850 temperatures are
still in the +8c to +12c range with lows in the 50s except some u40s
over the southern dacks/eastern Catskills/southern greens...and highs on Thursday in
the u70s to l80s in the valleys...and u60s to m70s over the hills
and mountains

Thursday night into Friday night...another brief break is expected
with the closed low embedded in the high amplitude longwave trough
over the eastern Continental U.S. Drifting north/NE towards James Bay. Wpc has weak surface
high pressure building in over New York and New England Thursday night...then
drifting downstream. Another weak impulse may trigger some isolated
showers/thunderstorms on Friday...but we kept it as a slight chance in the
grids. These may be tied more to the diurnal heating of the day.
Expect mainly dry weather Thursday and Friday nights. Lows will be mainly
in the 50s with perhaps a few readings close to 60f Friday night in the
capital district and middle Hudson Valley. Highs Friday will be close
to normal with widespread u70s to l80s over the hills and in the
valleys...with 70-75f readings common over the mountains

Saturday into Sunday...downstream ridging over the western Atlantic
will begin to build westward. The mean upper-level trough
retrogrades slightly upstream. Weak disturbances in the S/SW flow
aloft will focus scattered showers and thunderstorms on Saturday ahead of
a warm front just east of the Atlantic Seaboard. The humidity will
be on the increase...as the surface few dewpoints will be rising back into
the l60s with some middle 60s possible. The shower coverage may be a
bit more west of the Hudson River valley on Sunday...our forecast
reflects chance values north and west of the capital district with
slight chance values to the south and east. An isolated threat of
thunderstorms was included everywhere with the increase in humidity
and some instability. Temperatures will be seasonable for early August.

&&

Aviation /06z Monday through Friday/...
changeable flying conditions can be expected at all terminals over
the next 24 hours thanks to a strong storm system moving across
the area.

Some IFR fog is ongoing at kpsf/kgfl...with VFR conditions at
kalb/kpou thanks to building middle and high level clouds in place.
As an area of low pressure approaches from Lake Erie...showers and
possible thunderstorms will move towards the area towards
sunrise...with widespread MVFR conditions. Some of these showers
can be briefly heavy...and a tempo for IFR conditions within rain
showers has been included in the taf for all terminals.

There should be a break later in the morning...but another line of
showers and possible thunderstorms will occur in the afternoon as
the low pressure and it/S cold front passes across the area. The
potential for another brief period of IFR conditions will be
included in all tafs as a prob30 group.

Behind this front...westerly winds will transport cooler and less
humid air into the region. This will end the threat for
precipitation...with surface winds increasing to around 10 kts with a few
higher gusts for Monday evening into Monday night. Some lingering clouds
will continue into Monday night...but flying conditions should be
VFR for all sites.



Outlook...

Tuesday: no operational impact. No sig weather.
Tuesday night: no operational impact. No sig weather.
Wednesday: no operational impact. No sig weather.
Wednesday night: moderate operational impact. No sig weather.
Thursday: moderate operational impact. Chance of rain showers...tsra.
Thursday night: low operational impact. No sig weather.
Friday: low operational impact. Slight chance of rain showers...tsra.

&&

Fire weather...
low pressure will organize in the eastern Great Lakes tonight and
track northeast across New York. Rain and scattered thunderstorms
will overspread the region tonight into Monday. This storm will
depart Monday night and cooler air will filter into the region.
Middle weeks weather will be dominated by Canadian high pressure over
the Great Plains building slowly east and a large disturbance
aloft.

A rainy period with strong thunderstorms is expected through
Monday. So...relative humidities are expected to be greater than
60 percent through Monday night. High pressure and dryer weather is
expected to build into the region Tuesday with relative humidity values dropping
to 40 to 50 percent.

Winds will be variable at 15 miles per hour or less through tonight. Winds
will become west to northwest Monday at 10 to 20 miles per hour...diminishing
to 15 miles per hour or less Monday night and Tuesday.

&&

Hydrology...
isolated showers and thunderstorms are expected through this
evening. More widespread rain and thunderstorms are expected late
tonight and Monday morning...transitioning to locally heavy showers
and isolated thunderstorms during the afternoon.

Total rainfall of 1 to 2 inches is likely through Monday...with
locally higher amounts in thunderstorms. Locally heavy
rainfall may result in minor flooding of urban areas...poor
drainage locations and low lying 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...iaa/NAS/wasula
near term...iaa/NAS/wasula
short term...NAS
long term...wasula
aviation...frugis
fire weather...NAS
hydrology...NAS

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