Area forecast discussion
National Weather Service Albany New York
757 PM EDT Sat may 18 2013
Synopsis...
high pressure continues to move east of New England tonight
with clouds increasing. Meanwhile...moisture over the plains and
the Mississippi River valley associated with a warm front will
approach during the second half of the weekend with an increasing
threat for showers tomorrow...which will extend into most of the
upcoming week.
&&
Near term /until 6 am Sunday morning/...
as of 730 PM EDT...no major changes with high pressure shifting east
of northern New England. Light showers have shifted south and east of
forecast area with some drier air filtering in based on satellite and
radar loops. Increased winds slightly in capital region based on
observations with S/southeast breeze. Sky grids also changed slightly
with mostly cloudy conditions from Mohawk Valley/capital
region/Berks south. Lows tonight will be in the 40s to lower 50s.
&&
Short term /6 am Sunday morning through Monday night/...
significant model differences exist on Sunday with the GFS now
forecasting a rainy day for much of the forecast area on Sunday. The
other models still show gradually increasing moisture across the
region with mainly scattered shower activity possible...especially
during the afternoon. Have forecast probability of precipitation to increase to between 30
and 40 percent by later Sunday afternoon and continue at that level
through Sunday night. Based on current radar and satellite trends...
the 12z GFS run already seems to be in error so have generally
discounted the rainy day scenario. (The GFS is currently forecasting
a tenth of an inch or more of precipitation to occur across the southern part
of the forecast area before 00z this evening...even though radar
trends show the precipitation remaining to the south and also moving further
away this evening).
Highs Sunday will be in the 60s to lower 70s...with the coolest
temperatures over the south due to more cloudiness. Lows Sunday night will
be in the upper 40s to middle 50s.
A warm air mass will be surging toward the region Monday and Monday
night...with both the NAM and GFS statistical guidance indicating
dewpoints rising to 60 or more in many areas. A frontal boundary
will also subside slowly south into the region during that
time...thereby keeping the threat of showers going Monday and Monday
night. Have forecast probability of precipitation generally between 30 and 40 percent during
this period and also included a slight chance of thunderstorms
Monday afternoon and evening due to the increased instability. Highs
Monday will be in the 70s...and the lows Monday night in the middle 50
to lower 60s.
&&
Long term /Tuesday through Saturday/...
HPC guidance. A quasi-stationary frontal boundary across our region
will be the focus of possible showers and thunderstorms during the
work week. A cold front expected to sweep through about Thursday
night will bring an end to the unsettled conditions...to provide a
nice start to the weekend that follows.
Tuesday will be the warmest day of the period as the front is
expected to be at its northernmost extent across the state. Highs
will range mainly from the lower and middle 70s across the high
terrain...to the lower and middle 80s south and valleys...with a few
upper 60s in the highest peaks of the Adirondacks. Highs Wednesday
and Thursday will range from the middle and upper 60s in the
mountains...to the upper 70s in the middle Hudson Valley. Post
cold-frontal highs on Friday and Saturday will range from around 60
degrees in the Adirondacks and greens...to the lower 70s in the
Hudson Valley.
Overnight lows will become progressively cooler...with readings
bottoming out in primarily the 50s and lower 60s Tuesday night. By
Friday night...readings will average around 10 degrees cooler.
Normal highs and lows for Albany for the period are lower 70s and
around 50...respectively.
&&
Aviation /00z Sunday through Thursday/...
a warm front will slowly approach from the middle Atlantic region and
Ohio Valley overnight into tomorrow...as high pressure drifts east
of the Gulf of Maine.
VFR conditions will prevail prior to midnight...but then clouds
will start to thicken and lower with some MVFR stratus developing
in the low level S/southeast flow due to the return flow from the
retreating surface anticyclone...and some weak warm advection
increasing well in advance of a warm front. Some light rain or scattered
showers will gradually develop from kpou north/NE to kpsf between 13z-
16z...and then to kalb to kgfl between 16z-20z. Ceilings will lower
initially to 1.5-2.5 kft above ground level...and then possibly as low at 1.0
kft above ground level at kpou late in the afternoon. Visibilities are expected to
initially stay in the VFR range...but lower to MVFR range /4-5 sm/
in the late afternoon.
The winds will be from the S/southeast at 5-10 kts at kalb/kpsf
tonight...and become light and variable at 5 kts or less at kgfl
and kpou. Expect the winds to increase from the south or southeast
at 7-12 kts by the late morning to early PM with a few gusts close
to 20 kts at kalb due to funneling up the Hudson River valley.
Outlook...
Sun night...VFR/MVFR. Slight chance or chance -shras.
Monday-Monday night...VFR/MVFR...chc -shras/slight chance -tsras.
Tue-Thu...VFR/MVFR. Chance -shras/-tsras.
&&
Fire weather...
wind tonight will be south or southeast at 5 to 10 miles per hour...and south
the southeast at 5 to 15 miles per hour on Sunday with some gusts to 20 miles per hour.
Relative humidity values will rise 90 percent or more tonight. Relative humidity
values will remain relatively high on Sunday...between 50 and 70
percent.
&&
Hydrology...
overall quantitative precipitation forecast on Sunday should remain at or below one tenth of an inch
with the chance of showers beginning Sunday...mainly during the
afternoon. The chance of showers will continue through most of next
week...but the best chance for significant rainfall will be during
the middle to late 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.
New York...none.
Massachusetts...none.
Vermont...none.
&&
$$
Synopsis...gjm/wasula
near term...gjm/wasula
short term...gjm
long term...elh
aviation...wasula
fire weather...gjm/bgm
hydrology...gjm
