Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
1014 am EDT sun Oct 4 2015
low pressure will drift east from the Georgia coast today before
moving northeast off the eastern Seaboard through midweek. High
pressure will build into the central middle-Atlantic from the
northwest Monday night through Thursday. A cold front crosses the
region by next Saturday.
Near term /until 6 PM this evening/...
light returns being noted on the reflectivity as of 14z...with
mainly dz being reported at sites in Nova. The region remains
positioned between high pressure to the north and low pressure
near the Carolinas...keeping a tight enough pressure gradient to
produce gusty north winds. As the low pushes east and north later in
the period...the high will slowly pivot to the south...weakening
the gradient and the winds.
Concerning precipitation...low levels remaining saturated per 12z kiad
sounding and ceiling reports of around 1kft across the County Warning Area. Weak
subsidence around 500mb should keep the drier air aloft for most
of the day...with the next shortwave not moving into the middle Atlantic
till tonight. So while probability of precipitation will exist through the day...not
expecting much in terms of accumulate with the precipitation being even more dz
than rain most likely.
Temperatures on track to still hit the 60s for most areas east of the
Blue Ridge...and 50s to the west.
Coastal flooding remains the main hazard of concern...please refer
to tide section for more information.
Short term /6 PM this evening through 6 PM Monday/...
low pressure near South Carolina will very slowly slide eastward
tonight and Monday. High pressure will remain to our north.
However...Hurricane Joaquin will continue sliding north in the
Atlantic well to our east and this will allow the pressure
gradient to shift a bit. In turn...winds will continue to gain a
more northerly source region which should allow the continued
drying of the low levels...eventually resulting in the clouds
breaking up on Monday. The gradient should also finally
relax...more due to the weakening of the high to our north than
anything else...so while winds will still be noticeable they won't
be quite as strong. Lows in the 40s and lower 50s tonight will
rise to highs in the 60s in most of the area Monday.
Long term /Monday night through Saturday/...
Monday night into Wednesday...low pressure system slowly moves
northeast from off the Carolina coast to well east the New England
coast along the Gulf Stream. Northerly/northeasterly flow is maintained over the
central middle-Atlantic through this time with the only notable
pressure gradient east from the Chesapeake Bay.
Therefore...welcome sunny/clear and tranquil conditions are
expected. Temperatures will rebound to near or just above normal
with Tuesday/Wednesday maximum temperatures at/just above 70f. Min temperatures in the 40s
inland/low 50s east Monday night... and 50s Tuesday night.
High pressure crosses the northern middle-Atlantic Wednesday night
through Thursday night with more sunny/clear and tranquil. Truly
our Reward for the gloomy start to October.
A cold front will cross the central middle-Atlantic from a northern middle-
Atlantic low tracking east either Friday night or Saturday
according to GFS/European model (ecmwf) respectively. Chance probability of precipitation warranted for
whole County Warning Area...went for Friday night as peak pop timing for now.
High pressure and northwesterly flow then the rest of next weekend.
Aviation /14z Sunday through Thursday/...
IFR/MVFR conditions noted this morning.With the exception of
kmrb...visible are VFR...with ceilings being the main issue. Will
persisting lower ceilings through the day...with improvement not expected
till aftr 00z. Light rain or drizzle possible today...with minimal
Winds northerly 10-15kts with occasional gusts 20-25 kts...dropping blw 10 kts
tonight. VFR conditions the second half of tonight and on through
VFR as weak high pressure builds from the northwest Monday night through
Thursday with mainly light northerly flow. Cold frontal passage Friday night or
gusty northeast wind continues today on the water with gales
likely to continue on the Bay with Small Craft Advisory on the more protected
waters. Winds will begin to diminish tonight and Monday with Small Craft Advisory
conditions becoming widespread late tonight and Monday.
Small Craft Advisory expected to continue for main portions of Maryland part of the Bay
Monday night into Tuesday evening as the upper low that has been
parked over the southeastern Continental U.S. Moves NE offshore.
Weak high pressure builds Monday night through Thursday mainly 10
to 15 knots northwesterly flow Tuesday night and Wednesday.
coastal flood warnings in effect District of Columbia and St Marys County to account
for moderate flood levels forecasted to be reached through the high
tide cycles this evening. Coastal flood advisories for
Baltimore/Anne Arundel/Calvert/Charles and King Georges for minor
flood levels being reach today.
Tidal anomalies remain between 1-2.5 feet across the waters this
evening...and the forecasts are tracking the etss and estofs
guidance using our typical procedures much better than in past
days. As with the marine headlines...the tidal headlines were all
extended through tonight. St Marys is extended through Monday
Water levels should begin to drop a little by Tuesday...but
current wind directions are still north-northeast which does not
favor much of a drop.
District of Columbia...coastal Flood Warning until 5 am EDT Monday for dcz001.
Maryland...coastal Flood Advisory until 2 am EDT Monday for mdz014.
Coastal Flood Advisory until 3 PM EDT this afternoon for
Coastal Flood Warning until noon EDT Monday for mdz017.
Coastal Flood Advisory until midnight EDT tonight for mdz018.
Coastal Flood Advisory until 4 am EDT Monday for mdz011.
Virginia...coastal Flood Advisory until 3 PM EDT this afternoon for
Coastal Flood Advisory until 5 am EDT Monday for vaz054.
Marine...Small Craft Advisory from 6 PM this evening to 6 PM EDT Monday
Gale Warning until 6 PM EDT this evening for anz531>533-
Small Craft Advisory from 6 am to 6 PM EDT Monday for anz534-
Gale Warning until 6 am EDT Monday for anz534-537-543.
Small Craft Advisory until 6 PM EDT Monday for anz530-536-538.
Small Craft Advisory until 6 am EDT Monday for anz535.