Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Baltimore Maryland/Washington District of Columbia
935 PM EST Sat Jan 31 2015

high pressure builds across the region overnight. Low pressure
will approach from the west Sunday...crossing the region Sunday
night. High pressure will return for the first half of the week. A
cold front is expected to move into the region Thursday.


Near term /through Sunday/...
Winter Weather Advisory issued for north and west Maryland sun-Mon...

Near term forecast remains on track with little change. Cold dome
of high pressure will remain over the region tonight. Mostly clear
skies combined with light winds will keep temperatures cold
overnight. Readings as of 02z have already dipped back into the
upper teens to 20s in most locations. Temperatures will fall off a little
further until cloud cover increases from west to east tonight.
Expecting overcast conditions by daybreak Sunday.

On Sunday...surface low pressure approaches from the west and warm
air advection will begin to overrun the cold surface temperatures.
Very light precipitation is expected to develop mainly over the
northern and western sections around midday with coverage
increasing as the day GOES on. The bulk of the precipitation is
expected to occur Sunday night into Monday morning.

Precipitation type is still a challenge for tomorrow as warm air
overrides a shallow cold airmass. A wintry mix is expected almost
everywhere at the onset. The precipitation will mix with and
change to rain from Washington District of Columbia and points south by early
evening. The far north and west suburbs of Baltimore and Washington District of Columbia
will hold onto a wintry mix a bit longer. Our highest confidence
for an extended period of snow...sleet and freezing rain is over
northern and western Maryland. A Winter Weather Advisory has been
issued for these locations. Slippery travel from snow and icy
conditions are most likely in these locations. If the colder air
remains in place longer...the advisory may need to be expanded
further south.


Short term /Sunday night/...
wintry mix changes to freezing rain over the northern most portion
of the forecast area with rain expected from the metropolitan areas and
points south. Overnight temperatures near freezing north to the
middle to upper 30s south are expected.


Long term /Monday through Saturday/...
front expected to push eastward with the low Monday morning or
afternoon. Think for the most part drier air will arrive before a
changeover to snow will occur...with the exception being in
northern Maryland. Temperatures will fall behind the front during the
afternoon and winds will increase. There will be a period of
upslope snow with a few inches possible. These snow will come to
an end Monday evening as drier air and high pressure builds in
from the west. This high will also usher in an Arctic airmass with
temperatures dropping into the teens and some single digits.

High pressure will dominate the region Tuesday and Tuesday
night...bringing dry conditions and light and variable winds.
Despite some sunshine Tuesday...temperatures will remain nearly 10
degrees below normal.

A cold front will move across the region Wednesday and Wednesday
night. There is a chance of snow Wednesday night into Thursday on
the cold side of the front with the onset possibly mixing with a
little rain Wednesday evening. Temperatures will not be as cold
Wednesday and Wednesday night.

Temperatures Thursday through Friday will take another plunge to 10
to 15 degrees below normal as a cold dome of high pressure builds in
to the north of the departing cold front. Dry conditions will
persist through the period.


Aviation /03z Sunday through Thursday/...
clouds will be on the increases overnight...possibly dropping into LIFR during
day. Light snow possible around 12z iad/dca and north...then a chance of r/ice pellets during
the afternoon.

IFR likely Sunday night as low pressure crosses the area. Mixed precipitation
during the evening will transition to rain overnight at most of the
terminals except kmrb. Cold front passes Monday morning and
improves conditions but introduces strong northwest winds through

VFR conditions Tuesday through Wednesday. Winds northwest 10 knots Tuesday
diminishing light and southerly 5 to 10 knots Tuesday night. Winds S
becoming west 5 to 10 knots Wednesday.


winds will remain below Small Craft Advisory critieria overnight.

Low pressure tracks just north of the waters late Sunday night with
a cold frontal passage Monday morning. Rain will be predominant
precipitation type over the waters. Strong northwest winds behind the front...may
be in the gale category. Winds decrease late Monday night.

No marine hazards expected Tuesday through Wednesday.


Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...Winter Weather Advisory from noon Sunday to 8 am EST Monday
for mdz003-501-502.
Winter Weather Advisory from 3 PM Sunday to 8 am EST Monday
for mdz004>006-507.
WV...Winter Weather Advisory from noon Sunday to 8 am EST Monday
for wvz051-052.


near term...krw

National Weather Service Glossary of Abbreviations