Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
436 am EDT Tuesday may 26 2015
scattered showers and thunderstorms will be possible today through
Thursday, as a warm and increasingly moist air mass, prevails
across the region.
Near term /until 6 PM this evening/...
a southwest flow of increasingly moist air will continue over the
region today. The upper level ridge axis is now situated along the
East Coast with middle level short waves expected to ride along the
western edge of this ridge in the southwest upper level flow.
Models suggest a middle level short wave currently in the Ohio Valley
will lift NE and across the southern tier/NE PA later this morning and
through the afternoon hours. Will continue with isolated
convection through middle morning with probability of precipitation increasing to high chance
across the southern tier and NE PA this afternoon. Model soundings not
really indicating much chance for severe weather this afternoon as bulk
shear values and middle level winds are marginal at best. Storm Prediction Center has
removed the marginal threat for all of New York state but Chautauqua County
and this seems reasonable. Any convection that does occur will
have the potential for heavy downpours as precipitable water are around 1.50
inches. Maximum temperatures will generally range in the lower to middle 80s.
Short term /6 PM this evening through Thursday night/...
tonight...with loss of diurnal instability and departing short
wave activity is expected to decrease to isolated coverage.
Another mild night is expected with lows in the lower to middle
Wednesday...a more well defined short wave along with a prefrontal
trough is expected to cross the area during the late morning/afternoon
period. Model cape is generally around 1000 j/kg but this combined
with better deep layer shear and stronger env winds will bring a
better chance for severe weather. Continued high precipitable waters around 1.60 inches
and unidirectional flow (small mbe vectors) indicates the
potential for training cells with heavy downpours. Increased probability of precipitation
into the likely category by afternoon across much of central New York
and high chance NE PA. High temperatures will be in the lower 80s.
Wednesday night...surface cold front will cross the area during the
overnight period. Will continue with scattered rain showers/thunderstorms and rain but
activity is expected to be weaker than Wednesday as instability will be
Thursday...cooler less humid air will slowly build over the area
but the southern half of the County Warning Area could still see scattered
convection especially over NE PA where instability will still
reside. Maximum temperatures will range in the middle/upper 70s across New York state and
lower 80s in NE PA.
Thursday night...mainly dry and cooler weather is expected as surface
high pressure over eastern Canada briefly builds over the region. Lows
will range from the upper 50s to lower 60s making for comfortable
Long term /Friday through Monday/...
230 am EDT update...
made minor adjustments to the previous forecast on probability of precipitation and temperatures.
Still looks to be a very active pattern. For more information
please read the previous forecast discussion below.
Previous forecast discussion...
overall pattern looks to be locked into a fairly modest ridge
over the western Atlantic with a broad trough of low pressure across
the central Continental U.S.. with respect to the daily details...there are
several differences in the medium range models which make this a
low confidence forecast. In general...the period looks to be warm
and humid with mainly diurnal chances for showers and
thunderstorms...but there still could be nocturnal or early
morning activity if upstream waves do not fizzle. Timing of a cold
frontal passage over the weekend is also up in the air. GFS wants
to blast it through the area on Saturday...while Canadian
hemispheric doesn't even approach northern New York by Sunday.
European model (ecmwf) is in the middle with a later timing...but does get a
semblance of a weakening front into Pennsylvania on Saturday
night. GFS typically breaks down ridges too fast...so will tend to
lean with the front getting here and have good chance probability of precipitation Sat-
sun...although northern/central zones may be fine by Sunday
afternoon...with nepa remaining in scattered shower/thunderstorm activity
throughout. Chances for showers/thunderstorms increase again across New York by
Monday as warm front begins to lift through. Although the forecast
will look somewhat pessimistic with rain chances each day...the
reality is we are not suggesting a washout...but rather typical
Summer like weather with much of the time dry in most areas
punctuated with passing storms. Heavy rainfall from thunderstorms
a distinct possibility with precipitable water values remaining higher than
Aviation /08z Tuesday through Saturday/...
VFR conditions are expected through much of the next 24 hours with
the exception of thunderstorms and rain. Over the next few hours expect a middle level
deck to drift south into the region. There will be a slight chance
for showers this morning over krme an ksyr. This afternoon...
expect scattered showers and thunderstorms to develop. Rain showers during
the early afternoon... then thunderstorms and rain during peak heating. The best
chance for thunderstorms and rain will be at kith... kelm... kbgm and kavp. These
showers may have MVFR visbys. Winds are expected to be southerly
through the taf period.
Tuesday night to Sat...periods of rain showers/thunderstorms and rain around the region during
this period with associated flight restrictions. Highest
concentration of activity will be during the Wednesday-Thursday period.