Area forecast discussion
National Weather Service Binghamton New York
144 PM EDT Wednesday may 22 2013
Synopsis...
a warm and humid airmass will remain over the region through
tonight. Scattered showers and thunderstorms are possible through
this period along with warm temperatures. A cold front will
approach the region on Thursday. This system will bring a better
chance for showers and thunderstorms through Friday morning.
&&
Near term /until 6 PM this evening/...
1010 am update...
busy weather day shaping up for the region as chances for renewed
convection and severe weather development appear likely as the late
morning/afternoon hours progress. First things first however with
middle-morning radar imagery showing weak showers currently moving
through the central southern tier and Finger Lakes on the heels of
a weak shortwave trough currently moving from western PA into
western New York. So far this activity has behaved but attention remains
focused on another area of shortwave energy which now resides across
eastern Kentucky and southern Ohio. With time today...this feature will
continue lifting northeast where it will encounter an increasingly
unstable airmass as temperatures warm well into the upper 70s and lower
80s later today.
Comparing today/S setup to yesterday/S...the one thing that is
immediately apparent is that the upper-level wind field is more
supportive of convective development as an anticyclonically curved
jet strengthens to our north in increasing confluent flow aloft. As a
result...much of upstate New York and northern PA will be placed under
the favorable right entrance region which will enhance upper-level
divergence across the region. This combined with increasing lift
arriving with the previously mentioned Ohio Valley shortwave should
provide plenty of middle/upper support for convective development.
Shifting closer to the surface...latest 13z subjective hand analysis
shows a leeside trough extending south from the Central Lake plain
south through central PA. Further to the north...a lingering
stationary front remains positioned across northern New York just north
of the County Warning Area which could serve as an additional focus for
development later today.
Summing everything up and considering that the 0-6 km bulk shear
vectors are forecast to increase to near 40-45 kts later
today along with unidirectional tropospheric flow...isolated
splitting supercells cannot be ruled out. Quick look at both the
12z buf and pit soundings still show nearly dry-adiabatic middle-
level lapse rates suggesting elevated mixed layer air still
resides across the region. Latest Storm Prediction Center day 1 outlook maintains a
slight risk County Warning Area wide with a 30% hail and wind risk. The other
concern remains heavy rain potential as blended tpw satellite
graphics continue to show an abnormally moist airmass in place
with precipitable water values approaching 1.50 inches. Obviously we/ll have to
watch things as they unfold as heavy rainfall from last night/S
convection on top of additional rains today may warrant a quick
Flash Flood Watch for portions of the lake plain and northern
Finger Lakes region.
430 am update... showers and thunderstorms continue across the western cats and
the southern tier as boundaries lurk in the vicinity. Very slight waves riding
up in southwesterly flow are acting to spark off convection and may continue
to do so at random tonight. Warm front appears to be located in the far
northern zones though it is a little uncertain on how far north this
feature will lift through the day. As it stands now, most of the County Warning Area
will be clearly in the warm sector along with strengthening winds
aloft.
With temperatures into the 80s once again and dewpoints into the 60s, convective available potential energy will
average around 1000 j/kg give or take. Strong WV at 500 mb forecast to appch from
the west toward 00z this evng, though any subtle feature can ripple through at
anytime. Thus, have started probability of precipitation off this morning as scattered and as WV
approaches and heating commences have gone closer to likely after 21z across northern zones
in vicinity of warm front. Given what happened yda, potential certainly
exists for severe weather as wind fields strengthen.
Given the uncertainty of development will hold off on Flash Flood Watch
for now and allow day shift to put up a short-fused watch once area
becomes more clear. As it stands now, rainfall totals of 2-4 inches
occurred in a short period of time yesterday evening across southern Onondaga, central
Madison and southern Oneida counties and these will be the areas to watch.
&&
Short term /6 PM this evening through Saturday/...
430 am update...
tonight will feature ul low ejecting east into the upper Midwest. Strong
srly flow will pump moisture into the eastern half of the country with
40mm precipitable water values poised to enter into the Tennessee Valley at this time. Expect
this to mv nwrd into the area tonight and with ul system appchg the
central Great Lakes by morning and ridge gradually starting to break
down, will likely see increases in probability of precipitation by 12z Thursday. Overnight lows tonight
expected to remain in the 60s under moist airmass.
By 00z Friday cold front will bisect County Warning Area. At this time it appears that anafront
precipitation will occur as ul trough lags behind fnt. Thus, have kept probability of precipitation in likely
range for a good part of the day and into the nighttime hours.
Instability is on the weaker side due to extensive cloud cvr, however it
appears winds and frcg will be strongest. So will maintain mention of
possible severe in the hazardous weather outlook.
Frontal passage occurs around midnight Friday night with ul trough still hanging back
to the west and not moving through until closer to 18z Friday. Will continue
with likely probability of precipitation through this time with just chance showers bynd. Strong cold air advection
will occur following frontal passage with overnight mins dipping into the 40s across
the lake plain with lows in the upper 50s across southeastern counties.
Cold air advection continues drg the day Friday with skies clrng from west to east and
temperatures barely making it to near 60f. Winds will increases as pressure
gradient tightens between surface lopres off the Atlantic Seaboard and
building 1030mb hipres. Fairly raw day compared to past week or so.
&&
Long term /Saturday night through Tuesday/...
Period begins with a large and cool Canadian hp building into the area in
the wake of a deep low over new eng. 800 mb temperatures drop to near 0c by
Sun morning with the possiblity of some leftover precipitation in the eastern zones.
Remainder of the period shows the hipres building in and with modifying
temperatures.Little to no chance of precipitation after Sun morning. Grnly flwd HPC guidance
for the period...although did lower the temperatures a bit to be closer to the
mex guidance.
&&
Aviation /18z Wednesday through Monday/...
Conv developed over the center of the forecast area but is moving away from the
taf sites. Short term models show a break in the action flwd by some
conv later in the period as another WV passes. Begain the taf period with
VFR conds and added tempo for conv later in the day. Cold fnt will
approach for late in the period so have forecast a chance of showers after 12z
with MVFR conds. With will gnrly be light and southwesterly through the period...but
with gusts possible in vicinity of trws.
Outlook...
Thursday/Thursday night...MVFR possible in showers/thunderstorms.
Friday - Sat...possible lingering restrictions in lower cigs/-shra.
Sun - Monday...VFR. Breezy.
&&
Bgm watches/warnings/advisories...
PA...none.
New York...none.
&&
$$
Synopsis...pvn
near term...cmg/pvn
short term...pvn
long term...dgm
aviation...dgm
