Area forecast discussion
National Weather Service Albany New York
425 am EDT Tuesday may 21 2013
Synopsis...
warm and humid conditions will continue today with a
frontal boundary becoming stationary across upstate New York and New
England. A disturbance moving along the frontal boundary will focus
some showers and thunderstorms during the afternoon and evening
hours. The humid and unsettled weather continues tomorrow and
Thursday with more chances of showers and thunderstorms before a
cold front returns drier and cooler weather for Friday and into the
Holiday weekend.
&&
Near term /until 6 PM this evening/...
as of 424 am EDT...a broad ridge at 500 hpa is situated over the
eastern Continental U.S....with a slow moving upper low over the Central
Plains. At the surface...our region remains in a warm
sector...with a very slow moving boundary situated across the
northern portion of our area.
Moving along this surface boundary and aided by a strong SW low level
jet...a broken line of convection continues to move across the
Adirondacks and Mohawk Valley. This line has weakened from earlier
in the overnight hours when it produced wind damage and hail
across cny and the Lake Ontario region. Still...a quick downpour
and some gusty winds will sweep from west to east from the
southeastern adks and central Mohawk Valley into the Lake George
Saratoga region for the next few hours through sunrise. Most areas
from the capital region on south will stay dry. By shortly after
sunrise...this batch of convection should be done and most areas
across the County Warning Area will be dry.
However...additional showers and thunderstorms will develop during
the heating of the day as a surface wave along the front begins to
approach the area. Our local hires WRF suggests that some showers or
storms may begin to develop over the high terrain by the late
morning or early afternoon hours. The 3 km hrrr guidance seems to show
that it could hold off until the early to middle afternoon hours. In
either cases...once showers and thunderstorms develop they should
move to the W-SW.
With maximum temperatures reaching the upper 70s to middle 80s across the
area...and dew points well into the 60s...there should be sufficient
instability for thunderstorms. With 0-6 km bulk shear of 20-35 kts and middle
level lapse rates of about 6-7 degrees c per km...there could be
enough of the ingredients in place to allow a storm or two to
become strong to possibly severe. Storm Prediction Center has placed our region in a
/see text/ area for today...and we will have to watch if any
storms grow tall enough to produce some damaging wind gusts. We
will highlight this in our severe weather potential statement as well.
&&
Short term /6 PM this evening through Thursday night/...
ongoing convection this evening looks to continue into tonight as
the surface wave moves along the boundary. The best chance for seeing
showers/thunderstorms will be across the northern portion of the area.
With the loss of heating...any severe threat will be diminished...but
thunder should still continue due to lingering elevated
instability overnight. Min temperatures will continue to be mild and
muggy with upper 50s to middle 60s across the area.
The surface boundary will lift northward as a warm front on Wednesday.
The ridge axis will start to shift eastward as the upper low over
the plains slowly moves eastward. Despite the weak large scale
forcing...there looks to be a continued threat for showers/thunderstorms as
a pre frontal trough may be in place across our area by afternoon.
Plenty of moisture and instability will be in place...especially with
warm temperatures reaching the 80s in most areas...and dew points in the middle 60s
f. Any storm will again be capable of producing damaging
winds/large hail...and Storm Prediction Center has placed a good chunk of our area in
a slight risk for severe storms. Will highlight this in the severe weather potential statement as
well.
Showers and thunderstorms may linger again into Wednesday night
with continued mild and muggy conditions. Mins will only drop into
the 60s...with middle to upper 60s in the Hudson Valley.
The upper trough will finally begin to make some steady eastward
progress on Thursday into Thursday night. A surface cold front will
advance eastward during this time as well. This front will be a
focus for additional showers and thunderstorms...especially for Thursday
afternoon into Thursday night. Ahead of this boundary...there will be
one last warm and muggy day...with maximum temperatures in the 70s. Min temperatures
will start to cool off by Thursday night will the boundary moving
through...with mins in the 40s and 50s across the area...with the
mildest temperatures in southeastern areas.
&&
Long term /Friday through Monday/...
a cold front should exit the region through the day Friday with
lingering showers and thunderstorms in the morning in New York and into
the afternoon in western New England. There should be decent
boundary layer forcing with a tight thermal and moisture gradient
along the cold front...so will keep an eye for any strong
thunderstorm potential. Boundary layer temperatures should fall
through the day...and high temperatures should be capped around the
middle 60s to around 70...but in the middle to upper 50s in the southern
Adirondacks.
Once the cold front is gone...high pressure gradually builds in
through the weekend and into the beginning of next week. Some
lingering cloudiness could affect the middle Hudson Valley into western
New England Saturday as the cold front could be slow to exit those
areas. However...any shower activity should remain east of our
area. Highs Saturday in the middle to upper 60s...upper 50s southern
Adirondacks.
For Sunday and Monday...increasing sunshine and slowly moderating
temperatures. Highs Sunday in the upper 60s to around 70 and on
Monday...highs around 70 to the lower 70s. Temperatures cooler in
the southern Adirondacks both days.
&&
Aviation /08z Tuesday through Saturday/...
mostly clear sky across the region early this morning...with a weak
warm front across northern New York. Some fog has formed at kpsf and
acknowledging IFR fog temporarily MVFR through about 14z at kpsf. A
band of showers and thunderstorms over Lake Ontario is moving
east...and the southern edge of the convection is near ksyr. There
is a gust front ahead of the convection that is moving at around 35
knots...but based on the steering flow seen on radars across the
region...this convection should mainly track due east.
Area 00z soundings also show enough instability across the region to
sustain the convection as it tracks through eastern New York and into
western New England. However...it is timed to reach the Hudson
Valley around 09z...and with continued stabilizing of the atmosphere
through the early morning hours...and weakening of the
convection...just indicating vcsh at kgfl...kalb and kpsf...although
the best chance of a shower or thunderstorm would be kgfl based on
radar trends. Will amend tafs an hour or two prior to a shower or
thunderstorm if radar suggests strength of convection and movement
continues.
Outside of these showers and thunderstorms...some patchy MVFR fog
and some scattered variable broken clouds around 1500 feet are
possible through about 14z. Once whatever rain tracks east of the
region...broken clouds above 3000 feet temporarily scattered through
the afternoon. Some scattered showers or thunderstorms could
develop late in the afternoon and into the evening...but no real
organized focus so leaving out any vcsh for now...but may be added
in later taf issuances today once the character of convection is
known when it forms.
Winds should be nearly cal through about 14z. Winds should become
light south to southwest at less than 10 knots later this morning and
continue this afternoon and evening.
Outlook...
Tuesday night...VFR/MVFR. At kalb and kgfl -shra likely with chance thunderstorms and rain.
At kpsf and kpou chance -shra/-tsra.
Wednesday...VFR/MVFR. Chance -shra/-tsra especially during the afternoon.
Wednesday night...VFR/MVFR. At kgfl and kalb -shra/-tsra likely. At
kpsf and kpou chance -shra/-tsra.
Thursday...MVFR with IFR possible. -Shra/-tsra likely.
Thursday night...VFR/MVFR. Chance -shra/-tsra especially in the evening.
Friday...mainly VFR. Chance -shra mainly in the am.
Sat...VFR. No sig weather.
&&
Fire weather...
no fire weather concerns through at least Thursday due to on and off
showers and thunderstorms across the region. Relative humidity values will recover
to near 100 percent at night...and relative humidity values will generally stay
above 50 percent during the daytime hours.
&&
Hydrology...
no widespread Hydro service areas problems are expected the next 5
days. Some locally heavy downpours of rainfall may occur today
through Thursday within any thunderstorms. 3-hour zonal ffg values are
generally in the 2.4-3.1 inch range at this time...which are high
for middle to late may.
Due to the scattered nature of the showers and thunderstorms...
basin average quantitative precipitation forecast will be highly variable this week. The best
threat for seeing significant amounts of showers or thunderstorms
will from this afternoon into this evening and again on Thursday
afternoon into Thursday night. While it/S difficult to pinpoint
exact amounts...guidance from the weather prediction center /wpc/
suggests that most areas will see between one half inch and an inch
and a half of rain through Saturday evening...with the highest
amounts across the Adirondacks.
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...frugis
near term...frugis
short term...frugis
long term...NAS
aviation...NAS
fire weather...frugis
hydrology...frugis/wasula
