February 21, 2015 February precipitation has been nearly normal,
plus or minus 1/2 inch or so, for southern New York, northern-most and
eastern-most Pennsylvania, and New Jersey. The least precipitation
has been in central and south-central Pennsylvania where amounts are
1/2 to over 1 inch below normal. It has been a very cold month so far
with temperatures running 9 to over 11 degrees below normal. Over the
past 90 days, precipitation for much of southern New York and most of
Pennsylvania has been 1 to 2 1/2 inches below average. The Catskill
Region of New York, southeast Pennsylvania and northwestern New Jersey
are about normal plus or minus an inch or so. And the rest of New
Jersey has had 2 to 4 inches of above normal precipitation.
Snowpack continues to increase with significant differences from
north to south. Snow depth amounts of mostly 10 to 24 inches are
reported on the ground in southern New York. 6 to 12 inches are on
the ground in the northern half of Pennsylvania and northern New
Jersey. Less than 6 inches is on the ground in the southern half of
Pennsylvania and the rest of New Jersey. The water equivalent in this
snow, or the amount of water that will be released when it melts,
ranges from 2 to 4 inches in southern New York (where the deepest snow
is reported). 1 to 3 inches of water equivalent is on the ground in
most of Pennsylvania and northern New Jersey. The southern third of
Pennsylvania along with the rest of New Jersey have under 1 inch of
water equivalent. This amount of snow will have minor to moderate
hydrologic significance if it melts in the absence of an accompanying
rainstorm. However, if accompanied by a significant warm-up and
rainfall, melting snow could then have a moderate or greater effect on
river rises. In addition to the snow, ice covers many streams and
rivers and is likely to continue to increase in the coming days.
Current (February 21) streamflow data from the U.S. Geological
Survey shows that streamflows are running below or much below normal
in most areas. Groundwater levels are below or much below normal in
southern New York, most of Pennsylvania, and northwest New Jersey.
Groundwater levels are near or below normal in central and
south-central Pennsylvania. And, flows are mostly above normal in the
rest of New Jersey.
The weather outlook through the first week of March calls for near
normal precipitation. Temperatures are expected to be below or much
below average. The NWS Climate Prediction Center's 30 day outlook for
March calls for near average precipitation and below normal
temperatures. The 90 day outlook for March through May calls for near
average precipitation and temperatures.
The outlook for water resources and water supplies is "good" across
southern New York, Pennsylvania, and New Jersey. Though some
indicators (precipitation deficits, streamflows, and groundwater
levels) suggest dry conditions, an increasingly significant snowpack
is in these same areas, which is likely to offset any short term
dryness when the snow eventually melts. However, if below average
precipitation continues as winter begins to wind down, then this
outlook will likely be downgraded in the coming weeks.