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Area Forecast Discussion (AFD)

Issued by Albany, NY (ALY)

                            
000
FXUS61 KALY 230738
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
338 AM EDT Mon Sep 23 2019

.SYNOPSIS...
Welcome to the official start of autumn as a cold front will
cross the region today. This front will be accompanied by
showers and a few thunderstorms across eastern New York and
western New England. A cooler, less humid and somewhat
unsettled day is in the forecast for Tuesday with ample cloud
coverage and some passing showers. High pressure moves in for
Wednesday with moderating temperatures. Another frontal boundary
approaches on Thursday with the threat of showers. 

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM EDT...The Storm Prediction Center has placed the
northern 3/4ths of our region into a 'marginal risk' of severe
weather. The synoptic set up evolves an upstream cold front and
increasing mid-level jet from the Ohio Valley. GOES 16 overnight
satellite imagery reveals the increase in high level moisture
continues as mid-level cloud deck was evolving quick across
western and central New York, mainly north of I90 at the present
time due to theta-e advection. Pre-frontal trough axis is 
expected to move into western portions of the CWA later this 
morning with a sct-bkn line of showers with a tendency for 
those showers to weaken with eastern progress as it outruns 
upper level support. The more potent dynamic piece is expected 
to arrive later this afternoon. Low and mid level lapse rates 
increase with daytime heating with values at or above 6 c/km,
just unclear how much early autumn sunshine will occur. Combine
that with the aforementioned mid level jet and more enhanced 
surface convergence, more showers and thunderstorms will 
develop. While SPC has placed the region in a marginal risk with
isolated wind damage potential due to increase shear, the best 
instability, per HREF, would be from Albany and points to the 
west and northwest of the Capital Region. SBCAPE values of up to
1k j/kg with lowering wet bulb zero heights where deeper 
convective updrafts may support some small hail. As coverage and
intensity remain in question, we will not add in enhanced 
wording at this time. Timing of convection remains between 2pm- 
10pm EDT. Rather warm and muggy day ahead with highs into the 
80s for valley locations and mainly 70s elsewhere, with 
dewpoints into the 60s for most of the region. 

The cold front will continue to progress east-southeast Monday
evening the best PoPs to the east and southeast of the Capital
Region. Thereafter, mid level dry slot ahead of the upper low
and associated height falls approaches with a decrease in 
coverage and intensity of convection. Under increasing cold
advection, an occasional brisk west-northwest wind will be felt
as overnight lows dip back into the 50s for most of the region
under variable cloud coverage. 

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Tuesday...Cyclonic flow and vorticity will be across most of the
region on Tuesday with considerable cloud coverage to the north
of the mid-Hudson and portions of Litchfield County CT where
some showers are also expected. Timing of the cold pool, H500
values at or below -15C, could see an isolated lightning strike
from the Capital Region and points north-northeast of the area.
Regardless, a brisk and much cooler day than recently with highs
into the 50s for the higher terrain, 60s for most valley
locations to around 70F for the mid-Hudson Valley and southern
portions of Litchfield County. 

Tuesday night to Wednesday...The upper low departs across New
England and out east of the Gulf of Maine as high pressure
builds in across the region. A period of tranquil weather is
expected with a mostly clear and cool night Tuesday night lows
mainly into the 40s. Highs Wednesday rebound as warm advection
gets underway with lower 70s for valley locations and 60s
elsewhere (near normal for the end of September)

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The next cold front and associated upper level shortwave trough will 
be making its way towards the area for Wed night into Thursday. With 
this system making its way towards the area from the northern 
stream, moisture looks pretty limited.  Can't rule out some brief 
showers ahead of the front for Wed night into Thursday (mainly for 
areas north/west of Albany) but total rainfall looks very light and 
some areas will wind up remaining dry.  Temps look to be a little 
above normal, with lows in the 50s for Wed night and highs on 
Thursday reaching the 70s for valley areas.

Behind the front, it looks a little cooler for Thursday night, as 
skies start to clear out and temps drop down in the 40s. Ridging 
looks to be in place for Friday, making for a dry weather with temps 
in the 70s.

Over the weekend, strong upper level ridging will extend from the 
Deep South,  across the Southeastern US and towards the western 
Atlantic.  Our region will be situated on the northern fringe of 
this ridging, with general west to southwest flow throughout the 
troposphere.  Temps aloft at 850 hpa and 700 hpa will be about 1 to 
2 STD above normal, and max temps look to reach well into the 70s 
for much of the area for both Sat and Sun.  Most areas should stay 
dry, but can't rule out a stray shower sneaking into northern or 
western areas at some point over the weekend, as northern stream 
storm systems ride up and around the ridge. Overnight lows will 
continue to be mild, with mainly 50s (some mid to upper 40s in the 
mountains) and no frost expected anywhere across the region.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Satellite imagery and surface observations show sct-bkn high level 
clouds over the region.  These clouds look to continue through the 
remainder of the overnight hours with VFR conditions continuing. The 
combination of a southerly breeze at 5 to 10 kts and the high cloud 
cover will prevent any radiational fog from forming this morning. 
Along with the surface winds, 2 kft winds will be around 30 kts 
through sunrise.  This won't be enough differential for LLWS, but 
still something to note for the next few hours.

During the day on Monday, flying conditions will continue to be VFR. 
 Clouds will gradually increase and lower, with cigs becoming bkn-
ovc at 5-8 kft by the mid afternoon hours.  S-SW winds will be 
around 10-15 kts through the day.

Some showers may spread towards the region for the late afternoon 
into the evening hours. These will mainly be light in intensity and 
brief in duration.  Cannot totally rule out a rumble of thunder, but 
coverage looks to low to include any thunder in the TAFs at this 
time.  Will include a PROB30 for the chance of flying conditions 
lowering to MVFR within a shower (mainly for VSBY).  Otherwise, it 
should remain VFR through the evening hours.

With the passage of a cold front late Monday evening, clouds will 
start to decrease and showers will end.  Winds will become westerly 
around 5 kts for Monday night. Just some sct clouds will continue 
around 6-12 kft for all sites with VFR conditions.

Outlook...

Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: Low Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: Low Operational Impact. Slight Chance of SHRA.

&&

.FIRE WEATHER...
Welcome to the official start of autumn as a cold front will
cross the region today. This front will be accompanied by
showers and a few thunderstorms across eastern New York and
western New England. A cooler, less humid and somewhat
unsettled day is in the forecast for Tuesday with ample cloud
coverage and some passing showers. High pressure moves in for
Wednesday with moderating temperatures. Another frontal boundary
approaches on Thursday with the threat of showers. 

The RH values will drop to 50 to 80 percent by this afternoon. 
The maximum RH values Tuesday morning will be in the 85 to 100 
percent range.

The winds will be south to southwest increasing to 10 to 20 mph
during the afternoon before veering to the west to northwest at
10 to 20 mph by the late afternoon into the early evening. 

&&

.HYDROLOGY...
No hydrologic problems are anticipated across the region over
the next 7 days. 

The next chance of rain will be ahead of a frontal boundary and
an upper level disturbance on later today into Tuesday morning.
Most spots will see between one tenth and one third of an inch 
of rain, which will have little impact on area rivers and 
streams...maybe flows will rise a few centimeters and then 
recede. 

According to USGS streamflow, most area rivers are
seeing near normal or below normal flows for mid to late
September.

Lingering showers on Tuesday (especially for northern areas) may
yield additional rainfall amounts of a few hundredths to a 
tenth of an inch. 

More dry weather is expected for Tuesday night into the mid
week period.

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...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...Frugis
AVIATION...Frugis
FIRE WEATHER...BGM/Wasula
HYDROLOGY...BGM/Wasula

www.weather.gov/albany