Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Binghamton New York
659 PM EST Tuesday Dec 1 2015
periods of rain and drizzle will be common through Wednesday as a
series of low pressure systems move across the region. Cooler
weather is expected on Thursday with a mixture of rain and snow
Near term /until 6 am Wednesday morning/...
0650 PM update...as of early this evening, rain diminishing in the
area with the next batch still pretty far upstream over western
PA. For this reason, lowered pop and quantitative precipitation forecast for this evening. For the
first part of this evening, not expecting much...just some patchy
drizzle with some spotty showers. Next batch of rain associated
with occlusion doesn't look to arrive until late evening into the
overnight from west to east.
Original discussion...the forecast is straightforward in that we
do not have to deal with winter precipitation types tonight...yet rather
complex in terms of timing rounds of more significant rainfall
through the region. Late this afternoon and early evening...the
main forcing for rain remains across northern and eastern
PA...while patchy drizzle and scattered showers will continue
across central New York in the area behind the warm front aloft. Have
tailored the hourly pop trends to reflect the steady rain in the
south and more spotty precipitation to the north.
Later this evening and overnight...models suggest the approach of
the surface occluded front along with a minor supporting wave aloft
with rain probabilities returning to categorical.
Temperatures have also struggled to reach forecast maxes across
the Mohawk Valley which is playing havoc with the guidance and
tonight's minimum temperature. We expect a few more degrees from
Syracuse to Utica with a high in the evening...then fairly steady
temperatures. Similar idea for the rest of the area with not much change
from current conditions to the overnight low.
Short term /6 am Wednesday morning through Friday/...
not much change on Wednesday with a couple more surges of rainfall
expected as the major closed upper trough slowly moves into the
region. Trends in the guidance suggest any steady rain once again
tapering off to some light showers and areas of drizzle during
the early morning...then a secondary low pressure system develops
along the trailing surface front over Ohio and tracks across
Pennsylvania by Wednesday night. Another boost to the steady rain
develops for Wednesday afternoon and night with this
feature...keying in on the northern PA zones and the southern
tier of New York...and less probability the further north and west you
go across New York.
Changes come for Thursday into Friday as the lows move into New
England. Colder air filters into the region with a steady
northwest flow across Lake Ontario developing. This will allow for
a continuation of overcast skies and lake enhanced precipitation.
The lake-air temperature differences are not overly strong enough
for a significant event as 850 mb temperatures only drop to about
-6c...but this will be sufficient for a snow/rain mix depending on
elevation. A few spots could see up to an inch on the grassy
areas...but generally no issues.
Surface high pressure builds in for Friday with improving weather.
Models disagree somewhat on a middle level impulse diving out of the
northwest flow on Friday. For now it looks weak with limited
moisture and forcing concentrated across Canada and New England.
Will continue with a dry forecast as the low level flow also veers
to the west-southwest limiting lake potential.
Long term /Friday night through Tuesday/...
very little changes made to the extended forecast with high
pressure sprawling across much of the eastern half of the
nation...resulting in a generally dry forecast. Temperature
anomalies in this pattern also suggest above average readings for
Aviation /00z Wednesday through Sunday/...
restricted flight will continue across the region tonight and
Wednesday. Widespread MVFR is certain to dominate the pattern...
while areas of IFR visibilities and ceilings at times are plausible. Exactly
where and when is up in the air as we have several impulses of
light to moderate rain expected between now and 00z Thursday. An
attempt at timing the various impulses is outlined in each
terminal forecast...but model guidance disagreement lends to low
confidence. The general trend will be for deteriorating conditions
tonight with a possible category improvement during the day
tomorrow...although the second slug of rainfall in the afternoon
could change that idea.
Winds will remain moderate and gusty from the southeast at
elevated locations this evening...then diminishing to light and
variable. Sheltered airports will remain...or become light and
variable through the period.
Wednesday night...gradually becoming VFR/MVFR.
Thursday...VFR/MVFR. IFR possible in rain or snow showers in central