|Mesoscale Discussion 58|
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Mesoscale Discussion 0058
NWS Storm Prediction Center Norman OK
1025 AM CST Wed Feb 07 2018
Areas affected...Pennsylvania...New York...New England
Concerning...Winter mixed precipitation
Valid 071625Z - 072230Z
SUMMARY...Heavy snowfall will be possible from late this morning
into this afternoon from northern Pennsylvania east northeastward
across much of central and northern New York into New England.
Freezing rain will be likely in central Pennsylvania with a snow to
freezing rain transition taking place from southeast New York into
southern New England late this morning into this afternoon.
DISCUSSION...The latest water vapor imagery shows an upper-level
trough over the western Great Lakes region with strong west to
southwest mid-level flow located across the Northeast. A 90 to 100
kt mid-level jet max is analyzed by the RAP across the lower Great
Lakes. In addition, the exit region of a 60 to 70 kt low-level jet
is analyzed across northern Pennsylvania and central New York. These
two features are enhancing large-scale ascent across southwestern
parts of the MCD area. In response, widespread winter precipitation
is ongoing from Pennsylvania east northeastward into southern New
England. Forecast soundings suggest that thermal profiles are cold
enough for snow in northern Pennsylvania, central New York and
across much of New England where 1 inch per hour snowfall rates will
be possible through this afternoon.
Further to the south across central Pennsylvania and southern New
York, forecast soundings show a warm layer near 850 mb. This
combined with surface temperatures near or below freezing will be
favorable for freezing rain. As the low-level jet moves
northeastward, the warm layer will spread across southern New York
into southern New England where a transition from snow to freezing
rain is expected. Freezing rain rates should reach 0.05 inches per 3
hours across this area.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 42967091 42097230 41117504 40467716 40197804 40237844
40567862 40827864 41657848 43157725 44327526 45197201
45147013 44796928 44316885 43746975 42967091
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