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Area forecast discussion 
National Weather Service Albany New York
200 am EDT Monday Jul 25 2016

Synopsis...
hot temperatures, increasing humidity and chances for showers and
thunderstorms return today as a frontal boundary approaches from
the west. More dry weather is expected from Tuesday through the
middle of the week as high pressure builds back in across the
region.

&&

Near term /until 6 am this morning/...
minor adjustments to the forecast were made. Intervals of mid and
high clouds will continue to stream across region much of the
night. Observations across the area have calm winds as we head
into the overnight hours with a light south to southwest flow
beginning to develop toward daybreak. Overnight lows should mainly
be in the 60s, perhaps barely below 70 in some valley areas from
Albany southward.

Some showers/thunderstorms may approach from central New York toward
daybreak. Will continue slight chance to low chance pops across
the Catskills and Mid Hudson valley region to account for this
possibility.

&&

Short term /6 am this morning through Wednesday/...
there are quite a few different possibilities as to the evolution
and track of convection that develops in the lower Great Lakes and
Ohio Valley overnight. Various mesoscale models have different
solutions, some showing a weakened small cluster of showers and
isolated thunderstorms along the advancing dew point boundary
around or just after daybreak across the eastern Catskills and
Mid Hudson valley. Other guidance shows the small cluster tracking
well south of the Mid Hudson valley. Other guidance shows most of
all the showers and storms dissipating along the dew point
boundary through the night, but new strong convection rapidly
developing over eastern New York and western New England around mid
morning Monday.

The one constant is the dew point boundary with increasing dew
points building in from the west but the Mode and coverage of any
weakening showers and thunderstorms is very much in question.
Boundary layer flow will slowly increase from the west and
southwest, which is downslope, and there is very little upper
dynamics or upper jet support for convection in our region. So,
acknowledging isolated to scattered showers and thunderstorms
Monday morning into the western Mohawk Valley, eastern Catskills,
Mid Hudson valley and into northwest CT. This may be updated once showers
and storms can be tracked through tonight. Low temperatures with
the increasing cloud cover and increasing dew points in the 60s to
near 70...but around 60 northern areas and parts of southern Vermont.

Guidance again not in full agreement on coverage, timing and
intensity of convection tomorrow. Upper dynamics, upper jet
structure and low level forcing will be relatively weak through
the day but rapidly increasing low level moisture will contribute
to increasing instability. West to southwest boundary layer flow
will be downslope...suggesting scattered coverage, not necessarily
likely. The amount of mixed mid and high clouds will determine
high temperatures but as long as new convection initiates more in
the afternoon, intervals of breaks and thinning of mid and high
clouds should still allow for highs well into the 80s to lower
90s. Heat indices may approach 100 in the Mid Hudson valley and northwest
CT but not quite. So, will include in hwo, highlighting the chance
that a heat advisory may need to be issued later.

The instability, convective available potential energy may be solidly over 1000 j/kg in many areas
Monday afternoon, along with some hints at some degree of
steepening of midlevel lapse rates, suggests that even with the
scattered nature of the storms tomorrow afternoon, some could
become severe. Our region is in a marginal to slight risk in the
severe weather outlook from spc, with damaging winds the primary
threat but some hail could occur as well.

The better low level forcing along the advancing low level thermal
and moisture boundary and westerly wind shift looks to be during
the evening and overnight Monday night when some diurnal cooling
should be occurring but keeping potential severe in the forecast
through Monday evening. Some low level drying and partial clearing
could occur before daybreak with lows in the 60s.

Continued drying Tuesday with considerable sunshine and breezy
west to northwest winds. Highs Tuesday in the 80s to near 90.
Similar weather Wednesday but less wind with highs again in the
80s to around 90.

&&

Long term /Wednesday night through Sunday/...
this will be a stagnant period of little atmospheric motion to
get things moving. As such...our region will be more or less stuck
between two frontal boundaries north and south. Waves will ripple
along these boundaries...and showers and thunderstorm will be
possible each day...particularly approaching and during the
weekend.

After high temperatures from around 80 degrees in the mountains to
the lower 90s down the Hudson Valley on Thursday...showers and an
overall increase in cloud cover will keep daily highs in the around
70 degree...to lower or mid 80s range for the balance of the period.
Overnight lows will be in the upper 50s to upper 60s range for the
entire period. Daytime highs at Albany are in the lower 80s...with
overnight lows in the lower 60s.

&&

Aviation /06z Monday through Friday/...
high pressure will move east of New England this morning, as a
warm front moves through. A cold front will move across the region
late this afternoon and tonight.

Mid and high clouds continue to increase across eastern New York and
western New England this morning ahead of the warm front. A few
sprinkles or showers may graze kpou around 12z...but we left them
as a vcsh for now. VFR conditions should prevail into the early
afternoon.

As the warm front moves across eastern New York some isolated/scattered
showers and thunderstorms may occur in the early PM and vcsh
groups were issued. The better chc of thunderstorms will be ahead
of the cold front...and prob30 groups were used with thunderstorms
btwn 20z to 00z/Tue. Some brief reductions to MVFR/IFR conditions
will be possible in any thunderstorms.

VFR conditions are possible after 00z/Tue...but there maybe some
patchy MVFR mist around where any showers or thunderstorms occur.

The winds will be light to calm early this morning and then will
become south to southwest at 5-12 knots into the afternoon. Some
gusts in the 15-20 knots range will be possible in the afternoon
before becoming light after 00z/Tue.

Winds will be much stronger, and variable in direction in and near
any thunderstorms.

Outlook...

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

&&

Fire weather...
hot temperatures, increasing humidity and chances for showers and
thunderstorms return for Monday as a frontal boundary approaches
from the west. More dry weather is expected from Tuesday through
the middle of the week as high pressure builds back in across the
region.

Relative humidity values will range between 75 and 100 percent
tonight and Monday night. Relative humidity values will drop to
around 50 to 65 Monday afternoon and to around 40 to 55 percent
Tuesday afternoon.

Scattered thunderstorms are expected Monday and Monday night.

Winds will becoming variable around 5 kt or less tonight. Winds
on Monday will become southwest at 15 mph or less. Winds shift to
west and northwest at 15 mph or less Monday night, then increase
to around 15 mph with possible gusts to 25 mph Tuesday.

&&

Hydrology...
dry weather will occur through tonight. However, the next frontal
boundary will approach for Monday bringing additional chances for
showers and thunderstorms. Locally heavy rainfall will be possible
with any persistent storms but basin wide amounts should be a
half inch or less.

Dry conditions return for Tuesday and Wednesday as high pressure
builds back into the region.

Flows continue to be well below normal for mid to late July at
many locations in the Hydro service area, especially our western
New England counties.

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
near term...iaa/kl/NAS
short term...NAS
long term...elh
aviation...wasula
fire weather...NAS
hydrology...NAS

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