Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
117 PM EDT Sat Apr 25 2015
the upper level storm has moved just far enough away of
the Gulf of Maine to allow for more sunshine and less cool
temperatures today. It will however wobble back into Maine on Sunday
which will bring more clouds and the chance for showers again Sunday
into Monday. &&
Near term /through tonight/...
As of 1015 am EDT...still looking at
a mainly clear sky except for our Adirondacks and southern greens
where a few more instability cloud have formed.
Overall forecast looks to have a good handle on things...so with
this update just some very minor tweaks of the hourly grids. No
changes to high temperatures this afternoon.
A weak anticylonic flow (as opposed to a cyclonic one) should allow
our region to remain rather tranquil today. The only minor exception
to this would be some influence of Lake Ontario along with upslope
into the dacks where a shower or two could develop coinciding with
the maximum heating of the day. Diurnally driven cumulus/SC expected with
highs mainly into the 50s for valley locations and 40s for the
The next elongated upper trough axis just to the north of the
Great Lakes region begins to migrate southward tonight. Per the
NCEP model suite...timing of this feature will delay the onset of
precipitation as we will keep most of the region dry tonight. A mixture
of clouds and stars will allow for diverse temperature ranges from
20s into the terrain and middle 30s for valley locations.
Short term /Sunday through Monday night/...
the aforementioned upper trough axis slides further southward
Sunday into Monday. This will allow for both an increase in cloud
coverage and probabilities for showers. The showers will initially
be confined mainly into the terrain on Sunday then a more coverage
is expected on Monday. In fact...Monday we will see warm
advection/isentropic lift from the north as the upper low
completely wraps in Atlantic moisture. Due to the cloud coverage
and the increase chances for showers...this too will have an
impact to the temperatures as will shave off a degree or two from
MOS guidance. Some of the highest terrain will likely see some
rain/snow mixture with little to no accumulations.
This last piece of energy quickly moves off the middle Atlantic coast
as deepening cyclogensis commences well east of the coastline.
This too will quickly end the precipitation from northwest to southeast
Monday night. Some partial clearing will commence but due to the
warming thermal profiles...overnight lows will be a little milder
with lows generally ranging from 35-45f.
Long term /Tuesday through Friday/...
the slow moving cutoff upper level low will finally be moving away
from the region by Tuesday. Aside from an early morning rain shower
in far eastern areas...dry weather with a partly sunny sky is
expected for Tuesday with temperatures rebounding back towards seasonal
values...of low to middle 60s for valley areas...and middle to upper 50s
for the high terrain.
With weak ridging at 500 hpa building into the region...dry weather
with seasonable temperatures will continue for Tuesday night through Wednesday
night. Highs look mainly in the 60s...and lows in the middle 30s to middle
40s...with skies partly to mostly clear.
There is some uncertainty in how the end of the week plays
out...generally due to the unpredictable nature of the movement of
additional cutoff lows. While some models /such as the 00z GFS/
suggest that a cutoff low will dive across the region from Canada
for Thursday/Fri...other models /such as the 00z European model (ecmwf) and 00z Gem/
either keep these systems across Canada or over the southeastern US.
Also...while most deterministic models have seemed to back off this
idea...there is also the chance that the upper level energy over the
southeastern US could develop a surface coastal low that moves up the
eastern Seaboard for the late week or into the weekend...as seen in
a few members of the 00z gefs.
With all this in mind...will go with slight to low chance probability of precipitation for
Thursday/Friday for rain showers for now...but this will be subject to
change depending on model trends. Will continue to forecast temperatures
near normal levels...although it may be a cooler if more clouds/rain
showers occur...especially with the lower heights of an upper level low
Aviation /17z Saturday through Wednesday/...
VFR conditions will be expected at all taf sites throughout the taf period.
As our region is on the west side of an almost stationary upper
level low pressure system in the Canadian Maritimes...mostly clear
skies and some gusty northwesterly winds will be through 00z
Sunday. Once we go past 00z Sunday...more few to scattered cloud
coverage will begin to work back into the region. Broken ceilings
possible at kgfl closer to the upper level low pressure system but
still in VFR criteria. Clouds will be at all taf sites at varying
coverage past 12z Sunday through the end of the taf period
remaining at VFR conditions.
Winds will be gusting at or above 10 knots out of the northwest at
kgfl/kalb before 00z. Winds at all taf sites will be near calm from
00z-12z Sunday before gusting between 5-10 knots out of the west-northwest 12z
Sunday through end of the taf period.
Sunday night-Monday night: moderate operational impact. Scattered rain showers.
Tuesday-Wednesday night: no operational impact. No sig weather.
Thursday: low operational impact. Slight chance of rain showers.
minimum relative humidity values today will range from 25 to 35
A mainly dry day is in store for the region with a northerly wind
between 10 and 18 miles per hour with some higher gusts into the 20 miles per hour
range. Partial cloud coverage tonight with a recovery of relative
humidities between 70 and 90 percent.
The increase in cloud coverage and chances for showers will be in
the forecast Sunday into Monday. This will keep relative
humidities elevated with minimum values on Sunday ranging from 35
to 45 percent...then 40 to 60 percent on Monday.
the forecast will be dominated by a persistent upper level low
which will result in cool temperatures...breezy conditions and
chances for mainly light precipitation. Any of this precipitation
will have little if any impact on our rivers and streams in our
hydrological service area /hsa/.
Rivers and streams will continue to slowly recede with the cooler
temperatures and light scattered precipitation forecasted.
For details on specific area river and lakes...including observed
and forecast river stages and lake elevations...please visit the
advanced hydrologic prediction service /ahps/ graphs on our web-