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000 
FXUS61 KALY 201347
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
947 AM EDT Sun Oct 20 2019

.SYNOPSIS...
Expect a seasonably cool Sunday with skies becoming mostly
cloudy. A weak system may bring in some sprinkles or light rain
showers mainly for areas along and south of I-90. High pressure
quickly returns tomorrow giving way to sunshine and milder
temperatures. An occluded front looks to bring the next chance
for rain Tuesday into Tuesday night.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 947 AM EDT...Weak surface high pressure is located over
southern Maine, with the upper level ridge axis located across
New England.  Water vapor imagery shows plenty of high level 
moisture streaming northward across the mid Atlantic and 
Northeastern US. This moisture is associated with the remains of
what was once TC Nestor, currently located inland over the
Carolinas. Meanwhile, a surface upper level disturbance is
located over the Upper Midwest and Northern Great Lakes and will
be moving across Ontario through the day today. 

Despite the increasing moisture aloft, this morning's 12z KALY 
sounding showed plenty of dry air at low and mid levels of the 
atmosphere, with PWAT values of only 0.35 inches. MRMS imagery
shows a pretty solid area of rainfall over central and eastern
PA and this will be lifting northward through the day.

Based off 3km HRRR/NAM, this rainfall will continue to head
towards our area. However, it will be running into plenty of dry
air, and the best forcing with the southern stream low will be
exiting off the mid Atlantic coast. As a result, some light rain
is possible by afternoon for our area, mainly for areas
outside of the western Mohawk Valley and Adirondacks. Even
across the bulk of the area, this rainfall looks fairly spotty
and light, as it will be falling out of mid level deck and some
of the precip will be lost to virga. Models seem to agree that 
the heavier rainfall will be located across NJ/NYC area and 
southern New England. Best chance of seeing up to a tenth of an
inch of rain in our area will be across the Catskills, mid
Hudson Valley and NW CT. 

Daytime highs should reach the lower to middle 50s in valley
areas thanks to the cloud cover and possible rainfall. High
terrain areas will remain in the 40s.

Any precip will be ending this evening and clearing will occur
from west to east by the late evening hours. Surface high
pressure will quickly reestablish itself over the area, and
skies should be fairly clear by the late night hours. With the
clearing skies, light or calm winds and recent precip, this may allow
for some patchy fog to form, especially in valleys and/or near
bodies of water. Overnight lows look to be in the upper 30s to
mid 40s for most spots.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
An intensifying trough in the Central Plains should become a cut-
off low on Monday, allowing the ridge and associated surface 
high pressure building into the Northeast to strengthen. 
As subsidence aloft increases, early clouds on Monday should 
give way to mainly sunny skies. Temperatures should also warm 
into the low to mid 60s as the ridge axis shifts into New 
England and southwest return flow develops. 

Clouds increase Monday night as the aforementioned cut- off low
heads eastward towards the western Great Lakes resulting in 
increased southerly flow over the Eastern CONUS. Temperatures 
should not drop much in this flow regime with lows likely 
staying in the 40s. 

The mature cyclone's occluded boundary looks to push towards 
eastern NY/western New England during the day on Tuesday but
with strong ridging in place over the eastern seaboard, we 
slowed down the rate at which precipitation moves into our area.
We limited POPs to chance Tuesday morning as the best mid-level
moisture and warm air advection should be well to our west but 
after 18z, 850mb winds increase to 40-50kts which should allow 
precipitation to overspread first into eastern NY and then track
into western New England. QPF amounts through 00z Wed (8pm 
Tues) should range from around 0.30" in the Adirondacks/western 
Mohawk Valley down to a 0.10" in western New England. Rain 
continues into Tuesday night with more details on this in our 
long term discussion.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Guidance is in good agreement that a cold front associated with a deep 
stacked low over the western Great Lakes Region sweeps across 
the region Tuesday night producing a moderate to possibly heavy 
rainfall during the evening. A strong south-southeast low level 
jet at 850 mb of 35 to 50 knots will have transported moisture 
rich air into the region with precipitable water values of 1 to 
1.25 inches ahead of the front. The rain is expected to linger 
across the area with the passage of the front but taper off to 
showers by daybreak Wednesday. The storm is expected to weaken 
as it moves gradually moves northward across Ontario and 
Hudson's Bay Wednesday and Thursday. Any lingering showers 
Wednesday should be rather limited.

Guidance is in agreement short wave energy diving out of western 
Canada digs a deep trough across the central CONUS as we move 
through the latter part of the week. This results in 
southwesterly flow aloft across our region as higher pressure 
tries to builds in at the surface Thursday. However, guidance 
diverges as the ECMWF cuts an upper level low over Texas Friday 
while the GFS weakens the trough as it progresses eastward. For 
forecast consistency have used guidance from the Weather 
Prediction Center (WPC) to close out the work week and head into
the weekend with chances for showers as a cold front moves 
southeastward across the region Friday and Friday night. Refer 
to WPC's Extended Forecast Discussion (PMDEPD) for their 
reasoning.

Overall expecting seasonable temperatures with highs mainly in
50s and lows in the 30s and 40s.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Having a tough time dealing with fog in the TAFs. The 
dense fog has moved back in at KALB, with light fog occurring 
at KGFL and fog has been reported at KPSF. Overall an improvement 
is expected as the cirrus continues to stream in early this morning.


The remnants of Nestor are forecast to move off the mid-Atlantic coast 
Sunday remaining well south of Long Island. However guidance 
indicates some moisture is expected to be drawn into the region 
and with weak height falls some light rain is possible this 
afternoon across the area. Have addressed threat with a PROB30 
group in KPOU, KPSF and KALB TAFs. 

Very light to calm winds overnight with a light southerly flow developing 
Sunday at 6 knots or less. 

Outlook...

Sunday Night: No Operational Impact. NO SIG WX. Monday: No
Operational Impact. NO SIG WX. Monday Night: Low Operational
Impact. NO SIG WX. Tuesday: High Operational Impact. Likely
SHRA. Tuesday Night: High Operational Impact. Definite
SHRA...RA. Wednesday: Low Operational Impact. Breezy Slight
Chance of SHRA. Wednesday Night: No Operational Impact. NO SIG
WX. Thursday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
A wave of low pressure will be departing off the coast of the
mid Atlantic late today. Any lingering showers across
southeastern areas this evening will end, allowing for clearing
tonight. RH values will return to close to 100 percent late
tonight with dew formation and light northerly winds. On Monday,
plenty of sunshine is expected, allowing RH values to lower to
around 50 percent in the afternoon hours with a light northeast
wind of 5 mph or less. The next widespread chance of a wetting
rainfall will be on Tuesday into Tuesday night.

&&

.HYDROLOGY...
River levels continue to recede from last week's heavy rainfall.
Most smaller rivers and streams are back to normal base flow, 
although some of the larger rivers continue to slowly fall.
Meanwhile, many of the larger lakes and reservoirs continue to
be elevated at this time.

Although there may be some spotty light rain through this
evening (mainly for areas south of Albany), amounts will be 
very light (generally under a tenth of an inch) and this will 
have little to no impact on area waterways. Dry weather is 
expected for tonight through Monday night, allowing river levels
to hold steady.

The next chance of rain will arrive on Tuesday into Tuesday 
night, as a frontal boundary moves across the area. The bulk of
the rain looks to occur Tuesday evening.  Our current forecast 
is for about 0.50 to 1.25 inches of rain to fall, with the 
heaviest amounts across northern and high terrain areas. 
Overall, this rainfall will allow rivers and streams to rise 
once again, but it doesn't appear enough to cause hydrologic 
problems as of this time. 

Behind this system, more dry weather will return for Wednesday 
and Thursday, allowing river levels to recede. Another frontal
boundary could return some more showers for Friday into the
weekend.

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...Speciale
NEAR TERM...Frugis

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