Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
400 am EDT Monday Jul 6 2015
a warm front will lift north into the area today as a low pressure
system weakens over the region. High pressure briefly builds
Tuesday. A weak cold front will then enter the region Tuesday
night...then linger through the rest of the week.
Near term /through Tuesday/...
as of 07z...upper low center is over southeastern Ohio. This low will weaken
into an open wave today. There will be a slight warm front setting
up over the area. That will provide a focus for convection today.
However...the flooding threat is less than thought from previous
Lwx will be in the warm sector with plenty of cloud cover
persisting over the area. Morning rain will taper off...with the 06z
hrrr suggesting a middle morning reprieve before convective activity
begins in the late morning...increasing in coverage through the
afternoon. The dry slot from the low/trough looks to come into the
area late this afternoon providing more instability. Probability of precipitation are
highest today in the late afternoon and early evening hours as this
feature swings through. There is a marginal risk for damaging winds
in the late afternoon/evening convective storms. Maximum temperatures low to
The axis of the remnant upper trough shifts into the area tonight...
shunting activity east. Kept some probability of precipitation near the Chesapeake through
the night. Min temperatures mild...upper 60s west of the Blue Ridge...low 70s
Tuesday...southwesterly flow over the area with a swath of 20c 850 temperatures
suggest middle 90s if the clouds can clear. Went generally low 90s...an
increase previous forecast. Dewpoints in the middle/upper 60s would add a
few degrees in a heat index. Isolated thunderstorms near the Bay breeze and
in the terrain. Otw...negative vorticity advection behind the trough limits activity.
Short term /Tuesday night through Thursday night/...
low level moisture will increase from the south Tuesday night
ahead of a cold front forecast to cross the region on Wednesday.
The front will likely be accompanied by increasing chances for
showers and thunderstorms especially during the afternoon and
early evening. High temperatures on Wednesday will likely reach
the low to middle 80s west to the upper 80s to lower 90s east of the
Front will push offshore late Wednesday night into Thursday
morning and high pressure will build in briefly for the first part
of Thursday. Thursday will be slightly cooler but there will still
be a chance for scattered showers/storms during the afternoon and
Long term /Friday through Sunday/...
medium to long range pattern features a ridge of high pressure
over the southeast U.S with a series of weak upper disturbances
crossing the region through the weekend. This will lead to at
least of chance for scattered afternoon and evening showers and
thunderstorms each day. High temperatures in the 80s to near 90
can be expected.
Aviation /08z Monday through Friday/...
low pressure weakens over the central Appalachians today with a warm
front lifting over the area. Generally MVFR conds with some IFR ceilings
this morning and then in heavier rain showers/thunderstorm this afternoon/evening.
Southerly flow behind the warm front...gusting to around 15 knots. Flow
shifts southwesterly tonight with VFR and 15 knots southwesterly gusts Tuesday.
Mostly VFR conditions expected Tuesday night through
Friday...however...afternoon and evening scattered showers and
thunderstorms will be possible each day which could locally reduce
visibilities below VFR. Patchy overnight fog may also be possible.
warm front lifts into the area today with southerly channeling with 20 knots
gusts over southern Maryland Bay waters late this afternoon into the overnight
where there is an Small Craft Advisory. 10 to 15 knots elsewhere. Flow shifts southwesterly
tonight and 15 knots southwesterly flow expected Tuesday...will need to watch
for some 18 knots gusts across the waters.
Winds are expected to remain below Small Craft Advisory for much of the medium to
long range period. Occasional afternoon and evening thunderstorms
will be possible through the weekend. Any storm that does develop
could produce gusty winds...lightning and brief heavy downpours.
District of Columbia...none.
Marine...Small Craft Advisory from 5 PM this afternoon to 5 am EDT
Tuesday for anz533-534-537-543.