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Area forecast discussion 
National Weather Service Albany New York
209 am EDT Tuesday Aug 4 2015

Synopsis...
a cold front will continue to press southeastward across the
region overnight keeping the threat for isolated to scattered
storms in the forecast mainly south and east of the capital
district. The front will move slowly toward the coast during the
day Tuesday as another disturbance in the upper levels of the
atmosphere approaches and moves across the region triggering
scattered showers and thunderstorms.

&&

Near term /until 6 am this morning/...
a cold front continues to press southeastward across the area
with a short wave rotating about the base on the closed
low centered just north of the Great Lakes region. Scattered
showers and isolated thunderstorms occurring ahead of the
boundary. Only minor adjustments made to temperatures based on
observational data.

&&

Short term /6 am this morning through Wednesday night/...
Tuesday...the cold front will be near western New England by
daybreak. The surface dewpt boundary will still be progressing east
across eastern New York. The NAM is advertising alot of instability for Tuesday
with a deeply sheared environment. The GFS has less again...but
there is a small area of high instability from the the Mass Pike
south and east into northwest CT. Storm Prediction Center does have Litchfield city clipped by
the marginal risk. Middle level lapse rates will be around 6.5c/km
with another short-wave rotating around the upper level low. Will
have to monitor for some strong storms with gusty winds and small
hail /no enhanced wording yet/...especially from the capital
district south and east. Low- level cold advection will be ongoing
during the late morning into the PM. Downsloping effects off the
eastern Catskills/eastern dacks may allow maximum temperatures to get into the middle
and u80s in the Hudson River valley/capital region. Expect m70s to
l80s in most other locations...except over the southern dacks/southern
greens where some u60s to l70s are possible in the cold advection
regime...as h850 temperatures lower to +10c to +16c from northwest to southeast over
the forecast area by the late PM. A slight to low chance of thunderstorms
will continue until sunset.

Tuesday night...with the loss of the diurnal heating the scattered
showers and thunderstorms will diminish quickly. The isolated-scattered
showers may linger the longest over the southern dacks. Lows will
generally be in the middle 50s to around 60f with some u40s to l50s
over the southern dacks/southern greens. Humidity levels will be quite
comfortable.

Wednesday-Wednesday night...the forecast area will still be under the influence of
the upper level low centered over S-central Quebec. In the cyclonic
flow another piece of short-wave energy will swing across upstate
New York and New England. The best chance of isolated-scattered showers due to the
cyclonic vorticity advection will be north and west of the
capital region. H500 temperatures will be around -15c to -18c from aly
north and west. The h500 heights are about 2-3 Standard devs below
normal based on the latest gefs for Wednesday. H850 temperatures will be 1-2
Standard devs below normal. Highs on Wednesday will be in the m60s to l70s
over the mountains...and middle and u70s in the valleys...with a few 80f
readings near kpou. Clearing skies and light to calm winds will
allow for cool night for the first week of Aug...with high
pressure building in. Lows will range from the u40s to m50s over
the forecast area.

&&

Long term /Thursday through Monday/...
a return to much more comfortable weather is in store for this
period...and is expected to last. However...weak disturbances
intermingled with weak high pressure will mean rather small chances
for showers on some days...particularly the more southern zones...
which will be in closer proximity to a quasi-stationary middle-Atlantic
frontal boundary. If anything...the latter portion of the extended
period is expected to have the driest conditions...good news for
weekenders.

High temperatures in the middle and upper 70s...and low temperatures in
the 50s will be extremely common...with little day-to-day variation.
The normal highs and lows at Albany...respectively...are in the
lower 80s and lower 60s.

&&

Aviation /06z Tuesday through Saturday/...
a cold front continues to press southeastward across the area
with a short wave rotating about the base on the closed
low centered just north of the Great Lakes region. Scattered
showers and isolated thunderstorms occurring ahead of the
boundary. Have addressed threat for convection at taf
sites...kalb...kpsf and kpou...with vcsh.

As cloud cover decreases MVFR conditions are expected to develop
due to fog since the winds are calm and the ground damp/wet.

The cold front will move slowly toward the coast during the
day Tuesday as another disturbance in the upper levels of the
atmosphere approaches and moves across the region triggering
scattered showers and thunderstorms. Have addressed this threat
with prob30 groups in all tafs. MVFR conditions are expected with
any convection with brief IFR possible.

Calm winds will become southwesterly after sunrise...then shift
more to the west behind the boundary. The winds should become
gusty with gusts into the teens for a period Tuesday by late
morning.

Outlook...
Wednesday night-Thu: no operational impact. No sig weather.
Thursday night-Friday night: moderate operational impact. Chance of rain showers.
Sat: low operational impact. Slight chance of rain showers.

&&

Fire weather...
a pre-frontal trough and cold front will keep the chance of
showers and thunderstorms through the evening hours. Some of the
thunderstorms could contain some hail gusty winds and hail.

An upper level could generate an additional shower or
thunderstorm...mainly north of the capital region on Tuesday.

Otherwise look for a reduction in heat and humidity...especially
on Wednesday. With a cold pool aloft an additional shower is
remotely possible on Wednesday but otherwise it is dry.

The relative humidity values increase to 75 to 100 percent tonight. The relative humidity
values will lower to 35 to 55 percent Tuesday and Wednesday
afternoon.

South wind will become light overnight. The wind will become
west to southwest 5 to 15 miles per hour Tuesday afternoon and west to
northwest at 10 to 20 miles per hour on Wednesday.

The next chance for a wetting rain will be Friday.

&&

Hydrology...
widely scattered showers and thunderstorms this evening...some of
which have contained very heavy downpours (localized two inch
rainfall amounts). However...river basin averages will be closer
to a quarter inch. Other than the usual localized ponding of
water...there should not be much if any response on any of the
significant creeks or rivers across the region.

More widely scattered thunderstorms are possible Tuesday
afternoon...mainly north of the capital region. Little or no Hydro
problems are expected with these at this time.

Mainly dry Tuesday night through Thursday.

Then...a more widespread rain is possible for Friday.

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

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