Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1048 am EDT Monday Apr 27 2015
a slow moving upper level low will continue to allow for
plenty of clouds and some showers today. Drier and warmer weather
will return for the middle of the week. Some more rain showers are
possible later this week.
Near term /until 6 PM this evening/...
as of 1045 am EDT...some breaks in the clouds have developed
across portions of the immediate capital region...and middle Hudson
Valley. However...they are already quickly filling in as the
convective temperatures are met/exceeded. In fact...some light showers
have developed where earlier breaks occurred across the Saratoga
This morning/S 12z kaly sounding revealed deeper moisture...and a
weaker cap in place as compared to yesterday...which...in
combination with approaching middle level dynamics from the north and
northeast...should help promote isolated to scattered showers to
develop for the rest of this morning into the afternoon...with
more numerous coverage expected across portions of the southern
Adirondacks...and higher elevations across southern Vermont.
Sky cover should tend to become mostly cloudy to overcast for much
of the afternoon.
With cool temperatures in place aloft...mixing should occur to about 800
hpa or so. This will allow for maximum temperatures to reach into the 50s for
valley areas...although high terrain areas may only see highs in
the 40s. This is still about 5 to 10 degrees below normal for
this time of year. Temperatures may actually reach their maxes over the
next couple of hours...before falling once clouds and showers
develop. In addition...northwest winds of 10 to 15 miles per hour will be gusty at
times...with some gusts up 25 miles per hour possible...especially for the high
terrain where even higher gusts could occur.
Short term /6 PM this evening through Wednesday night/...
the upper level low will finally start to shift away from the
region tonight...as it begins to rotate back towards the east
across the western Atlantic Ocean. With weak ridging starting to
build into the area from the Ohio Valley...the threat for rain
showers should end overnight. Clouds will start to decrease by
late tonight...especially in the valley areas. Mins overnight look to be
in the middle 30s to middle 40s.
During the day on Tuesday...most areas look to wind up partly to
mostly sunny...although there still may be a decent amount of
clouds over the Adirondacks and southern Green Mountains through the day. It
should mix up to about 800 hpa once again...but with warmer temperatures
aloft...maximum temperatures look to reach the 60s for valley areas...and 50s
in the higher elevations. With good mixing occurring...it will be
breezy once again. As a result...there could be some fire weather
concerns...so please see our fire weather discussion below for
some important details on this.
Dry weather will continue through the remainder of the short term
period...as weak ridging remains in place at 500 hpa over our
area. With a partly to mostly clear sky for Tuesday night...temperatures
will fall into the middle 30s to low 40s. Plenty of sunshine and
warmer temperatures aloft will make for a nice day on Wednesday as
well...with highs near 70 in many valley locations and less wind
than Tuesday. There may be a few more clouds around for Wednesday
night...but it looks to remain dry with lows in the 40s.
Long term /Thursday through Sunday/...
Thursday through Friday...uncertainty remains in this portion of the
long term forecast period as the GFS remains the outlier with
phasing the northern and southern streams for a coastal low to
remain close to the middle Atlantic coastline. The
European model (ecmwf)/ggem/UKMET/NOGAPS along with several members gefs indicate the
coastal low that does develop would occur further south and east of
the operational GFS forecast position to limits its impact across
the region. The 1.5pvu trace from the operational GFS/European model (ecmwf) while
offer some indications that the two waves /one coming ashore across
British Columbia coastline and the well defined Four Corners upper
low/ will phase across the southeast Continental U.S....the key factor appears
to be the strength of the ridge situated from Nova Scotia to
Newfoundland. The non-GFS solutions are stronger with this feature
with the GFS not only weaker but displaced further west across
northern Quebec. So we will lower probability of precipitation a bit more during this time
frame and in line per the latest wpc guidance/collaboration. Thank
you to surrounding offices for the collaboration this morning. Due
to the cloud coverage...we will keep temperatures a bit more
Ridge is expected to build/crest across the region for the first
weekend of may with a return to Spring-like temperatures along with
partial sunshine. Following a non-GFS approach...a weak cold front
approaches Saturday night into early Sunday with a chance for some
showers. Otherwise...should not be a bad start to the month for the
region at this time.
Aviation /15z Monday through Friday/...
scattered-broken VFR ceilings across the region as lower ceilings were upstream along
with some showers. This trend will continue through the balance
of today into most of tonight. There could be a period of MVFR
ceilings with heavier showers and into the terrain where kpsf is
located. A little lower ceilings are expected tonight with a higher
probability for MVFR ceilings expected.
Winds will remain out of the north/northwest into the day
Monday...and generally be around 8-12 knots with gusts to 20 knots
after 14z. Winds will slowly subside tonight.
Tuesday night: no operational impact. No sig weather.
Wednesday: no operational impact. No sig weather.
Wednesday night: no operational impact. No sig weather.
Thursday: low operational impact. Slight chance of rain showers.
Thursday night: low operational impact. Slight chance of rain showers.
Friday: moderate operational impact. Chance of rain showers.
gusty winds and low relative humidity values look to occur during the middle week
An upper level storm system will continue to impact the region
today with a chance for light rain showers as well as plenty of
clouds. Relative humidity values will only drop to 40 to 60 percent this
afternoon with northwest winds around 10 miles per hour.
Relative humidity values will rise to 80 to 100 percent tonight with northwest winds at
5 to 10 miles per hour. Clouds will start to decrease late tonight.
During the day on Tuesday...the upper level storm will start to
move away from the region. This will allow for a partly to mostly
sunny sky with relative humidity values falling to around 30 percent in the
afternoon hours. Good daytime mixing will allow for northwest winds of 10
to 20 miles per hour...with gusts of 25-35 miles per hour possible. With significant
rainfall not having fallen for nearly a week...fire weather
headlines may potentially be needed based on coordination with
local and state officials and neighboring offices.
Relative humidity values look to recover for Tuesday night....but will drop once
again to around 30 percent on Wednesday afternoon. However...northwest winds
appear lighter on Wednesday...generally only around 10 miles per hour.
However...the lack of rainfall and warm temperatures in place may keep
fire weather concerns in place.
no hydrologic concerns are anticipated through this week at the
Light rain showers are possible today...but most areas will see
less than a tenth of an inch of rainfall. Dry weather is expected
for Tuesday into Wednesday...with a chance for rain showers
returning later this week. The amount of rainfall later this week
will depend on the exact track of a storm system moving across the
southeast...as well as influences from a northern stream upper
level storm system.
As a result...rivers and streams will generally slowly recede or
hold steady through the week. Nohrsc analysis continues to show a
very limited snowpack in place over the southern Adirondacks and southern
Green Mountains...which will continue to melt away through the
upcoming week. However...the areal coverage of this snow pack is
rather small...so it/S impact on rivers and streams of the region
will be rather minor.
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-