Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Binghamton New York
640 am EDT Monday Apr 21 2014

high pressure will bring another fair weather day to the area
today...with further warming resulting in highs in the upper 60s to
lower 70s. Clouds will increase into tonight...followed by a showers
Tuesday as a cold front passes. Behind that front...cooler
temperatures are expected through midweek.


Near term /through tonight/...
630 am update...
attempted radiational cooling from mainly clear sky...competed
with fairly robust warm air advection overnight...and some middle
level clouds also moved into central New York the last few hours.
Pressure gradient is such that atmosphere outside of the more
sheltered valleys stayed fairly mixed...thus not as cold this
morning. However...more sheltered valleys indeed realized
radiational there is currently a pretty big ridge-to-
valley spread in temperatures...and flatter terrain versus hilly.
Monticello at 6 am is only 30 degrees...Elmira 35 degrees...and Sidney
Norwich and Cortland also into the 30s...yet Penn Yan is 50
degrees and many other locations are in the 40s including Syracuse
at 47.

The continued warm air advection will lead to upper 60s to low 70s
for highs today...with sun filtered by some high thin clouds.
Pressure gradient actually relaxes...resulting in boundary layer
winds decreasing to mainly less than 10 kts and thus light winds
today even where full mixing occurs.

The high clouds thicken tonight...preventing radiational cooling
and thus mild temperatures expected with lows in the 40s to low
50s. GFS model is now the outlier in bringing in upper wave and
approaching front...and resultant quantitative precipitation ahead of 12z Tuesday. I
have sided with consensus of other models...and thus keep tonight
dry except for slight chance west of syr-ith-Elm line very late.
Rainfall with this system will wait until during the day Tuesday.


Short term /Tuesday through Wednesday night/...
330 am update...
a cold front and sharpening upper trough are expected to move
through the region with periods of rain on Tuesday. Models have
been really consistent with the driving now it is
just a matter of fine tuning the timing. Latest runs continue to
trend slightly slower with maybe just a chance for some leading
showers or sprinkles during the early daytime hours...but by late
Tuesday morning rain will be spreading quickly east through The
Finger lakes and twin tier regions. We expect the precipitation to probably
not start in the Catskills and Poconos until early afternoon. The
best chances linger in any one area for about 3-4 hours before
moving east by early evening. Some model indices suggest enough
instability for potential thunderstorms...but this looks overdone,
particularly by the NAM model. Can/T totally rule out a rumble or
two given the modest upper level forcing...but that/S not Worth
the full blown mention of thunder...storms.

Moving into Tuesday night...the main forcing and deep moisture leaves
the area by 00z...but sharp cyclonic flow aloft and destabilizing
low level northwesterly flow suggests scattered showers continuing
into much of Tuesday night. Thermal profiles aloft drop below zero
at 925-850 mb which will usher in colder air and possibly some wet
snow flakes. Have included mention of snow showers where temperatures
are forecast to dip below about 35 degrees. This was confined mainly
to the higher terrain across central New York. Cold northwest flow
will maintain an unstable upslope environment into Wednesday. The
trends offer up drying of the total atmosphere by late
some chance for showers or sprinkles exists for the first half of
the day...but by middle-late afternoon high pressure builds in at
the surface with less opportunity for precipitation. Surface-middle level
ridging is firmly in control by Thursday.

Because of the significant airmass change from tues-weds...
temperatures will fall well short of the upper 50s normality on
Wednesday...but recover nicely on Thursday with full sunshine and
gradual warm advection from the southwest by days end.


Long term /Thursday through Sunday/...
330 am update...
high pressure and milder conditions return on Thursday...but the
generally flat upper pattern across the northern tier states will
open the door for another frontal system to usher in showers for
Friday. The 00z European model (ecmwf) and GFS models then suggest the pattern is
showing hints at slowing down and amplifying as we move into the
weekend. The model solutions do differ quite a bit on placement
and timing of setting up a closed low over the northeastern third
of the country...but the signals are there for a cooler and more
dreary few days with passing possible showers at times right
through Sunday. Can/T say we are setting up for a washout...but
this is the season for closed lows...and those infamous April


Aviation /12z Monday through Friday/...
12z update...
VFR conditions will remain through 12z Tuesday. Only patchy high thin
clouds above 12 kft above ground level through 00z Tuesday...then some thickening of
those high clouds 00z-12z Tuesday ahead of incoming system yet still
mainly around or above 10 kft. Light east-southeast to south wind
early will become southwest less than 10 kts during the day...only
to revert back to light east-southeast to south tonight. Light
rain showers will be approaching from the west by 12z Tuesday...but
any impacts for our terminals will wait for during the day Tuesday.


Tue-Wed...some restrictions as showery front passes Tuesday...then
scattered showers and MVFR ceilings into Wednesday on back side of system.

Wednesday ngt-Thu...VFR.

Late Thursday ngt-Fri... restrictions possible in rain showers.


Fire weather...
415 am update...
as with will be very dry today yet winds will remain
light. A limited increase in moisture will be wiped out by further in the end relative humidity will again bottom out in
mainly the 20s percent range. Sustained winds out of the southwest
this afternoon will be under 10 miles per hour...and even peak gusts will
only barely eclipse that at times. Given these weather
conditions...continued drying of fuels can be expected today.
However...a good wetting rain is inbound for Tuesday courtesy of a
passing cold front...which will put a hold on fire weather


Bgm watches/warnings/advisories...
New York...none.


near term...mdp
short term...jab
long term...jab
fire weather...mdp