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Area Forecast Discussion (AFD)

Issued by Albany, NY (ALY)

                            
000
FXUS61 KALY 170432
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
1232 AM EDT Tue Sep 17 2019

.SYNOPSIS...
High pressure will build in from southeast Ontario over New 
York and New England tonight with cool temperatures and patchy 
fog. The surface high will bring continued fair weather and 
slightly cooler than normal temperatures through the mid week. 
Temperatures will moderate back above normal by the end of the 
week into the weekend with dry weather continuing.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 1230 AM EDT, nearly cloudless skies regionwide with the
exception of a few cloud patches close to the I-84 corridor in
the mid Hudson Valley. In areas where winds have trended to near
calm, temps have dropped off into the lower/mid 40s, while
remaining in the lower/mid 50s where some wind persists.

Still expecting patchy valley fog to develop through daybreak,
which could become locally dense. This potential looks to be
greatest across portions of the southern Adirondacks, upper 
Hudson Valley including the Glens Falls and Saratoga regions, 
as well as the Housatonic Valley and CT River Valley.

By daybreak, expect low temperatures to fall into the mid/upper
30s across portions of the southwest Adirondacks and sheltered
areas of southern VT, with mainly 40s elsewhere.

Patchy frost will be possible across portions of northern
Herkimer/Hamilton and northern Warren Counties toward sunrise,
away from any lakes/streams.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
Tomorrow...A nice day is expected tomorrow with slightly cooler
than normal temperatures, as the sfc high builds in over NY and
New England. The strong subsidence from the anticyclone will
yield sunny/mostly sunny skies after the patchy mist/fog burns
off in the morning. H925 temps will be +12C to +15C, as high
temps will be in the upper 60s to lower 70s in the valleys, and
upper 50s to mid 60s over the higher terrain.

Tue night...Another cool and tranquil night with similar
radiational cooling conditions as tonight. Clear/mostly clear
skies, light to calm winds with a very dry air mass, as temps
should fall once again into the upper 30s to mid/upper 40s. The
growing season officially ends for the southern Adirondacks Sept
21st. If temps fall further into the mid 30s or colder over a 
large portion of northern Herkimer, Hamilton, northern Fulton 
and northern Warren Counties, then Frost headlines may be 
needed. 

Wednesday...The sfc high remains anchored near southeast Quebec
and northern New England with northerly flow established aloft.
Boundary layer temps may be a tad cooler with a weak disturbance
/moisture starved/ moving across New England. H925 temps will
only be about +11C to +14C, as max temps with some mixing will
struggle to reach the 70s. Expect highs for locations below 1000
ft MSL to be in the mid to upper 60s with a few stray 70F
readings, and upper 50s to mid 60s for locations above 1000 ft 
MSL.

Wed night to Thursday...Persistent, dry pattern continues with
another cool night with widespread upper 30s to mid 40s for
lows. Portions of western New England will have to be monitored
for patchy/areas of frost, as temps cool more in later 
forecasts. Highs moderate slightly THU with the sfc high 
centered near eastern New England. A blend of the machine 
guidance yields 60s to lower 70s over the forecast area.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Rather quiet weather continues into the long term period with high 
and low temperatures warming above normal, reaching about 10 degrees 
above normal this weekend into early next week. This warm-up is a 
result of our upper level ridge and surface high pressure that has 
dominated our weather pattern for the past week shifting into New 
England. This pattern shift will lead to strengthening southwest 
flow and increasing warm air advection as our next cold front slowly 
approaches eastern NY/western New England Sunday night into Monday. 
After nearly a week without measurable rain, we will see an 
increasing chance for showers as we head into the new work week. Read 
on for details.


We begin the period Thursday night with a 590dm large scale upper 
level ridge centered over the Gulf Coast States dominating the 
weather pattern for areas east of the Mississippi River. With a 1025-
1030hPa surface high pressure centered off over New England, we 
expect mainly sunny/clear skies to continue over eastern NY and 
western New England as we head into Friday. With the ridge axis 
gradually shifting into the Great Lakes, upper level flow around the 
periphery of the upper level ridge looks to turn west-northwesterly 
which should allow warmer air to spill into the Northeast. This 
should result in temperatures warming above normal with highs 
reaching into the mid to upper 70s on Friday. Overnight lows should 
stay mild only cooling into the low to mid 50s.

As our ridge axis continues progressing eastward Friday night and 
Saturday, we expect temperatures to continue warming above normal. 
Most of the guidance continues to suggest a warm front will move 
through our region during the day on Saturday as the ridge axis 
finally crosses east of our area into the New England. This looks to 
should result in strengthening southwesterly flow as our area enters 
the warm sector with 850mb isotherms increasing to +14C to +16C 
which is about 1 to 2 standard deviation above normal for mid-
September according to the GEFS/NAEFS. In addition, the 
strengthening upper level flow and continued mostly sunny skies 
should allow deeper boundary layer mixing and high temperature 
should reach well into the 70s to even near 80 on Saturday and 
Sunday. While we note a few weak vort maxes rounding the top of the 
ridge, we continue to show mostly sunny skies due to lackluster mid-
level moisture.

By Sunday night, a cold front associated with an occluded mid-
latitude cyclone over Ontario will be gradually heading eastward 
towards the Northeast. The pressure gradient between the surface 
high pressure now off the New England coast and the approaching 
front should lead to slightly breezy conditions overnight and more 
so into Monday. With increased the winds a bit for Monday to show 
gusts up to 15-20mph. Strengthening southwesterly flow will also 
increase the dew points which should reach into the low 60s making 
it feel more humid Sunday night and especially Monday. The best 
height falls hold off until late Sunday night into Monday so we held 
off chance POPs for areas north/west of the Capital District until 
this period. Moisture again is not overly impressive and with the 
best forcing remaining well north of our area, we capped POPs to 
only chance and kept the highest probabilities for areas north of I-
90. We only introduced slight chance POPs for the mid-Hudson Valley, 
Catskills and NW CT given the lower confidence that showers reach 
these areas. Temperatures should stay warmer than normal Sunday 
night and even on Monday. Overnight lows Sunday night will be very 
mild only falling into the upper 50s to low 60s thanks to cloud
coverage. Given the increasing chances for showers and clouds,
high temperatures on Monday could be a few degrees cooler than
Sunday but still remain above normal reaching into mid-upper 70s
once again.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
An upper level trough will remain over the Northeast and 
southeast Canada with a high amplitude ridge over the central 
CONUS. While at the surface, high pressure will strengthen 
across the region and with it centered to our north cool 
Canadian air will settle in. 

With clear skies and very light to calm winds ideal radiational
cooling conditions will set up. Excepting some fog to develop 
overnight with MVFR-IFR conditions possible late at night/early
Tuesday morning with LIFR possible at KGFL. The fog will lift 
and burn off by around 11-13Z, then VFR conditions with only 
some cumulus clouds at KPSF expected. 

Light and variable to calm winds overnight with a light north 
to northeast flow developing Tuesday.

Outlook...

Tuesday-Saturday: No Operational Impact. Patchy FG possible 
late each night/early morning each day.

&&

.FIRE WEATHER...
High pressure will build in from southeast Ontario 
over New York and New England tonight with cool temperatures and 
patchy fog. The surface high will bring continued fair weather and 
slightly cooler than normal temperatures through the mid week. 
Temperatures will moderate back above normal by the end of the week 
into the weekend with dry weather continuing.

The RH values will increase to near 100 percent by late tonight
with with dew and patchy fog formation likely. The RH values
will lower to 35 to 50 percent Tuesday afternoon, and will
increase close to 100 percent Wednesday morning with more dew 
and fog formation. 

The winds will become light to calm tonight, and they will be
northerly at 5 to 15 mph on Tuesday, and will become light from
the north to northeast at 5 mph or less Tuesday night.

&&

.HYDROLOGY...
No hydro problems are expected in the Albany Hydro Service Area
/HSA/ for the next seven days. 

There are some abnormally dry areas in the ALY HSA based on the
most recent Drought Monitor, and there is a high probability of
dry weather over the next several days. 

The next chance of widespread rainfall will be with a cold 
frontal boundary will be on Monday. 

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.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...Wasula
NEAR TERM...KL
SHORT TERM...Wasula 
LONG TERM...Speciale 
AVIATION...IAA 
FIRE WEATHER...Wasula 
HYDROLOGY...Wasula