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Area forecast discussion 
National Weather Service Baltimore Maryland/Washington District of Columbia
359 am EDT Tuesday Mar 31 2015

Synopsis...
high pressure will slide to the south of the area today. Low
pressure and a trailing cold front will move through the region
this afternoon and early evening. High pressure will
then build through Wednesday before becoming a Bermuda high
Thursday. Another cold front is expected to cross the area Friday
into Saturday.

&&

Near term /until 6 PM this evening/...
low pressure is located near Chicago early this morning. The low
will continue to track quickly towards the southeast...across Ohio
and western WV through the morning hours and arrive in eastern WV
and western Maryland by early afternoon. Showers ahead of the front
still forecast to arrive near the Mason Dixon line either late morning
or early afternoon...and then across the area through most of the
afternoon. Best dynamics continue to be forecast near the low
itself...so highest probability of precipitation will be across the northern and eastern
portions of the forecast area. Soundings indicate just enough
instability for a few potential thunderstorms late this afternoon.
Gusty winds also expected this afternoon with a strong 700-850mb
jet stream moving through and good mixing. After collaboration
with neighboring offices...not enough confidence to issue a Wind
Advisory at this time...but will continue to monitor. High temperatures
forecast slightly higher than MOS guidance. Central Virginia and the
Piedmont will be the warmest where there will be less cloud cover
and more time for heating ahead of any rain...with temperatures in the
upper 60s to low 70s. Cooler near the Mason Dixon line...with
highs in the upper 50s.

The cold front will be to the south of our County Warning Area by midnight. Drier
and chillier conditions are expected behind the front with a
northwest flow overnight. Min temperatures will range from the low 30s in
the mountains to the lower 40s in downtown Washington and
Baltimore.

&&

Short term /6 PM this evening through 6 PM Wednesday/...
the cold front will be to the south of our County Warning Area by midnight. Drier
and chillier conditions are expected behind the front with a
northwest flow overnight. Min temperatures will range from the low 30s in
the mountains to the lower 40s in downtown Washington and
Baltimore.

High pressure will build into the middle Atlantic region on
Wednesday. Sunny and cooler conditions with highs in the 50s to
lower 60s can be expected Wednesday.

&&

Long term /Wednesday night through Monday/...
high pressure shifts offshore Wednesday evening...becoming a Bermuda
high Thursday. Upper ridge axis shifts east across the middle-Atlantic
Wednesday evening into Thursday morning. Return flow Wednesday night
and Thursday slowly returns moisture to the area. Positive vorticity advection ahead of the
next trough allows chance probability of precipitation late Thursday.

Warming trend Thursday and Friday ahead of the next cold front. With
dry and sunny conditions lasting into the afternoon hours and 10c
850mb temperatures crossing the area...Thursday may be warmest day of the
week. This is particularly the case if the 00z GFS is anywhere close
to being right with a more progressive cold front. Maximum temperatures
Thursday low to middle 70s for much of the County Warning Area...low 60s on western shore
of Bay. Humid Friday with areas S/east of District of Columbia warmest (mid 70s) as
clouds move in ahead of cold front with upper 60s/low 70s rest of the
County Warning Area.

Upper pattern becomes more zonal Friday into the weekend with low
pressure moving east from Colorado...lifting NE along the central
Appalachians. Bermuda high and this low opens the Gulf. 1.2 inch
precipitable waters prognosticated by 00z GFS which is near the maximum for early April.
Later shifts could probable add some heavy rain wording for
timeframe immediately ahead of the cold front. Hopefully greater
consensus on cdfropa occurs. Current thought is cdfropa late Friday
afternoon through Friday night.

Below normal temperatures on tap for Saturday in wake of cold front.
Will need to monitor broad northern stream trough dipping into the area
Sunday.

&&

Aviation /08z Tuesday through Saturday/...
VFR conditions Tuesday morning. Showers will move through the
region during the afternoon...with potential visibility reductions and
MVFR ceilings. Isolated thunderstorms possible late in the afternoon. Gusty
southwest winds will develop late in the morning and continue into
the afternoon. Gusts around 25 to 30 knots are expected.

A wind shift to the northwest is expected behind the front with
gusts around 20 knots. VFR conditions and dry conditions will
persist overnight.

VFR Wednesday with northwest winds 5-10kt.

High pressure shifts offshore Wednesday evening and becomes a
Bermuda high Thursday. Southerly flow until a cold front which is likely
to cross Friday night. Possible heavy rain ahead of that cold front
Friday evening.

&&

Marine...
potent low pressure will move toward the region this afternoon
before passing through the waters late afternoon or early evening..

Gusty southwest winds are expected to develop ahead of this system
by late morning. A Gale Warning is in effect for the waters
late morning through the afternoon. However...it will be marginal
and most gusts may end up being high-end Small Craft Advisory criteria due to the
relatively cooler waters. However...there will be a few showers
and perhaps even a couple thunderstorms that pass through the
waters ahead of the cold front late Tuesday afternoon and evening.
Despite limited instability...there is the potential for gusty
winds and small hail in heavier showers and thunderstorms during
this time.

The cold front will move south of the waters Tuesday night and
northwest winds are expected behind the boundary. A Small Craft
Advisory is in effect for all of the waters Tuesday evening...and
for the middle portion of the Bay and lower tidal Potomac River
overnight Tuesday. Winds will fall below Small Craft Advisory levels on Wednesday.

Small Craft Advisory expected all waters Thursday into Friday in broad return flow as
a Bermuda high sets up and a cold front approaches. Cold frontal
passage likely Friday night. Expect high end Small Craft Advisory/possible gale in
Post frontal passage northwesterly flow late Friday night and Saturday.&&

Fire weather...
a red flag warning has been issued for several Virginia counties
in The Highlands...Shenandoah Valley...Blue Ridge and central
foothills. Sustained wind are expected around 20 miles per hour with higher
gusts...and lowest relative humidity will drop below 30 percent this afternoon.
Fuel moisture is below required thresholds in this area. Further
east along the I-95 corridor and southern Maryland...fuel moisture
increases quickly above 9 percent...so the watch has been dropped.
An elevated risk continues however due to gusty winds and low relative humidity.
Any rain this afternoon will diminish the threat...so the warning
may be able to expire early in some locations. Otherwise the
threat will diminish by this evening with diurnally decreasing relative humidity.



&&

Tides/coastal flooding...
tidal anomalies have decreased due to the offshore flow. Another
surge of southwesterly winds will start up on Tuesday morning and afternoon ahead
of a cold front. Anomalies may quickly increase during this time
and water levels may approach minor flooding thresholds during the
high tide cycle Tuesday afternoon into Tuesday evening.

Gusty northwest winds will cause anomalies to rapidly fall behind
a cold front later Tuesday night.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...none.
Virginia...red flag warning from 11 am this morning to 6 PM EDT this
evening for vaz025>027-029-030-036>040-050-051-501-502-
504-507-508.
WV...none.
Marine...Small Craft Advisory from 6 PM this evening to 6 am EDT
Wednesday for anz532>534-537-540>543.
Gale Warning from 11 am this morning to 6 PM EDT this evening
for anz530>543.
Small Craft Advisory from 6 PM this evening to midnight EDT
tonight for anz530-531-535-536-538-539.

&&

$$
Synopsis...Kansas
near term...Kansas
short term...Kansas
long term...
aviation...baj/KS
marine...baj/KS
fire weather...
tides/coastal flooding...

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