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Area forecast discussion 
National Weather Service Albany New York
736 am EDT sun may 24 2015

Synopsis...
high pressure near the middle Atlantic coast will provide
pleasant weather for the second half of the weekend with
temperatures rising above normal. The south to southwest flow of
warmer and more humid air will continue into Memorial Day...as a
warm front will bring clouds and a slight to low chance of showers
and thunderstorms from the capital region northward. The air mass
will become more humid with temperatures rising well above
normal...and a threat of scattered showers and thunderstorms Tuesday
into Wednesday.

&&

Near term /until 6 PM this evening/...
as of 646 am EDT...surface high pressure has moved off the middle
Atlantic coast this morning...and temperatures will quickly rise as the
clouds have thinned to the north associated with the weak warm
front that grazed northern New York and northern New England.

The return flow of milder air on the west/SW side of the anticyclone
will commence with the boundary layer winds shifting to the
southwest today. H850 temperatures rise to +10c to +12c. The warm
advection pattern coupled with the local compressional
warming/downsloping effects in the SW flow will allow temperatures to
rise into the m70s to l80s in the valley areas /l80s will be
mainly in the capital district and the middle Hudson Valley/...and
u60s to m70s over the hills and mountains the skies will be partly to
mostly sunny with just some high clouds around in the afternoon.
The h500 ridge axis over the southeast/middle Atlantic region will be
strengthening with heights increasing over the Great Lakes region
and Midwest. Overall...temperatures should be 5 to 10 degrees above
normal...and much warmer than yesterday.

&&

Short term /6 PM this evening through Tuesday night/...
tonight...along the western periphery of the middle level ridge a low
pressure system will be moving into the upper MS River Valley and
west-central Great Lakes. Some middle and high clouds tied to a warm front
extending east from the system will migrate downstream into the
northeast. Also...a few warm advection showers with the warm front
may get into the Tug Hill plateau/western dacks between 06z-12z. A slight
to low chance of showers was kept in the forecast for the western Mohawk
Valley/wrn-srn dacks prior to daybreak. Lows will not be as cool
with lower to m50s over a large portion of the aly forecast area...and
some spotty u40s over the southern dacks...southern greens...northern Berks...and
eastern Catskills. Some low stratus may move into the S/southeast portion of
the forecast area well after midnight with the low-level S/SW flow.

Memorial Day...much of eastern New York and western New England gets into a more
humid air mass with the warm front moving north of the region
during the day. The short range guidance continues to vary in how
much warm advection shower/isolated thunderstorms and rain activity could impact the
region. The GFS is the most robust...but this model has had some
convective feedback issues in the past few weeks. The NAM is more
isolated-scattered in the late morning into the afternoon from the capital
region north and west. The ecwmf keeps it mostly dry from the I-90
corridor S/southeast with the closed h500 anticyclone just off the Florida and
Lower Middle Atlantic coast. A slight to low chance of showers was kept
in the forecast from the capital district...northern Catskills...northern
Berkshires northward. There is some weak instability indicated by
the NAM/GFS. The showalter stability indices still remain above
0c. A slight chance of thunderstorms was used in the afternoon into
the early evening. More clouds than sunshine is expected. Precipitable water
values do rise back to an inch or so. The Holiday does not look
like washout...but an umbrella may need to be handy from the Tri
Cities northward. Highs will be above normal with u70s to l80s
common in the lower elevations...and mainly 70s over the higher
terrain.

Monday night...the air mass becomes more moist and humid. Low
pressure moving across southeast Ontario moving along the rim of the
strong upper level ridge will pass north of the region. A weak
impulse in the west/SW flow aloft may focus some isolated-scattered
showers...and perhaps a thunderstorm especially from the northern
Catskills...capital region...northern Berks northward. Lows will range
from the lower 60s in the valleys...to m50s to around 60f over the
higher terrain.

Tuesday-Tuesday night...it will feel more like summertime again with a
warm and humid air mass over eastern New York and western New England. H850
temperatures may reach +15c to +16c. A weak disturbance in the southwest
aloft will increase the threat of scattered showers and
thunderstorms...especially tied to the peak diurnal heating.
Sbcapes increase to 500-1000 j/kg on the GFS with precipitable waters of 1-1.50
inches. The middle level lapse rates are not steep. 0-6 km bulk shear
are in the 20-30 knots range. Some loosely organized convection is
possible with locally heavy rainfall. It appears locations north
and west of the middle Hudson Valley/northwest CT would have the best chance of
showers and thunderstorms. Highs in the middle to u80s are possible
in the valley areas...with u70s to l80s over the hills and mountains
the convection should diminish in the evening with a sticky/muggy
night setting up with lows in 60s. Humidity levels will be
uncomfortable.

&&

Long term /Wednesday through Saturday/...
warm and muggy with chances of showers and thunderstorms.

Our region will be between ridging along the eastern Seaboard and
a large upper level low over hudson's Bay with short waves rotating
about it. As a result we will have deep southwesterly flow across
the region pumping a warm and humid airmass into the area.

A frontal boundary caught up in this flow is expected to gradually
approach from the west Wednesday and move into the region as it
weakens Wednesday night into Thursday. Another frontal boundary is
expected to approach from the Saint Lawrence River late in the week
and may move into the region over the weekend. These boundaries
would provide a focus for convection.

There is uncertainty in the timing and position of the boundaries and
more so with the timing of individual short waves which will aid
in the development of convection. Have favored guidance from the
weather prediction center to prepare the forecast to maintain
forecast consistency. There should be a lull in the convective
activity between boundaries...however with the airmass expected
to warm and humid diurnally driven convection can be expected.

Precipitable water values are expected to rise to 1.50+
inches...ahead of the boundaries so any thunderstorm will be
capable of producing heavy rainfall.

It is still too early to speculate on the potential for severe
weather as this will ultimately be dependent on the timing of the
boundaries and the amount of instability present...but it will be
something to watch...as the last few days of may are the
climatologically favored time for severe storms across eastern
New York and western New England.

At this time....the hottest day of the week is expected to be
Wednesday as the slow moving boundary approaches with highs
mainly in the 80s approaching 90 degrees in the Hudson River
valley. It will continue to be warm the rest of the week into the
weekend with highs around 10 degrees above normal generally in the
middle 70s to middle 80s.

&&

Aviation /12z Sunday through Thursday/...
VFR conditions expected through tonight as high pressure dominates.

Some middle level clouds will continue to move across the northern portion
of the local area...kgfl...early this morning as a warm front passes
to our north. Otherwise...heights rise aloft today as ridging builds in.
At the surface...high pressure centered off the middle Atlantic will gradually
drift eastward while maintaining a hold on the eastern Seaboard.
Mainly clear skies today...however high level cirrus clouds and some
middle level clouds will spill over the upper ridge as a piece energy
rides over the top.

Light southerly to calm winds early this morning. After sunrise a
southwesterly flow will increase and is expected to become gusty by
afternoon with gusts into the upper teens to lower 20s. Winds will
weaken this evening.

Outlook...
Memorial day: low operational impact. Slight chance of rain showers...tsra.
Monday night: moderate operational impact. Chance of rain showers...tsra.
Tuesday-Thu: moderate operational impact. Chance of rain showers...tsra.

&&

Fire weather...
..low relative humidity values of 20 to 30 percent this
afternoon...
..a few wind gusts around 25 miles per hour this afternoon...

Per request of the New England fire liaison contact points...a
Special Weather Statement has been issued to reflect "elevated"
risk of erratic fire behavior.

Eastern New York and western New England have greened up or leafed
out...and the keetch-Byram drought index plays an important role
in determining whether or not we have a "critical" fire day. The
current values are just below 300...so no headlines or statements
were requested in east central New York at this time.

The relative humidity values will drop to 20 to 30 percent this afternoon...then
increase to 75 to 100 percent Monday morning. The relative humidity values will
be higher Memorial Day afternoon in the 35 to 55 percent range.

The winds will increase from the south to southwest at 5 to 15
miles per hour today with a few gusts to 25 miles per hour. They will become light to
calm tonight...and then increase from the south to southwest at 5
to 15 miles per hour on Memorial Day.

&&

Hydrology...
no Hydro problems expected over the next 5 days...with river levels
holding or falling through the period.

Mainly dry conditions will persist into Memorial Day. A slight
chance to chance for showers and thunderstorms will return by late
Memorial Day afternoon into Tuesday...especially north and west of
the capital region. Any rainfall is much needed due to the recent
dry conditions. The U.S. Drought monitor has now included much of
eastern New York and western New England in the d1 category...which is
considered moderate drought.

The threat for scattered showers and thunderstorms will continue
through the middle week in the more humid air mass. Some locally
heavy downpours will be possible Tuesday through the middle week with
any thunderstorms.

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...wasula
near term...wasula
short term...wasula
long term...iaa/frugis
aviation...iaa
fire weather...bgm/wasula
hydrology...bgm/wasula

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