Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
355 am EDT sun Apr 26 2015
Low pressure along the Virginia-North Carolina border will move
off the coast this morning. An upper level low pressure system
will spin in the Gulf of Maine during the early part of the week.
High pressure will move into the area Tuesday. Another low
pressure system is expected to track across the southeastern U.S.
Wednesday...reaching eastern North Carolina Thursday evening.
Near term /today/...
As of 07z...1000mb surface low off Cape Hatteras which is riding a zonal
southern stream jet that stretches across the southern Continental U.S.. an upper low
center persists near Nova Scotia...but an upper trough extends west to
the Great Lakes. This upper trough axis will shift south to the middle-
Atlantic through Monday. The effect for today is a shunting of the
stationary front (currently over the central va) south into North
Carolina as a cold front.
A second round of precipitation has overspread the southwestern zones. Temperatures
are in the 30s through the column...but laps soundings suggest the
freezing layer is around 9kft...so this is plain rain. Southern half of
the County Warning Area has a chance for rain (categorical south of charlottesville)
with the threat of rain shifting south.
Today...rain shifts south of the County Warning Area through the morning. Northerly flow 5
up to 10 miles per hour with cloudy skies breaking with late morning partly
sunny skies expected before stratocu redevelopment given the moist
surface. Maximum temperatures generally higher to the north where more sun is
expected. Low 60s north...upper 50s for southwestern zones given more clouds
from the departing front.
Short term /tonight through Monday/...
Tonight...north wind increases 10 to 15 miles per hour late with cloudy
conditions as the zonal upper trough axis approaches from the north.
Min temperatures upper 30s northwest of balt-wash corridor and west of Blue
Ridge...low to middle 40s rest of the area. Dry.
Monday...upper trough from low off Maine slides into the area.
Generally instability with isolated/scattered light rain showers/sprinkles
expected to move in from the northwest. Snow flakes above about 2500 feet
elevation. Went a degree or two below mav/met/gmos blend due to
expected clouds. Breezy northwesterly flow 15 miles per hour with gusts to 25 miles per hour.
Long term /Monday night through Saturday/...
Conds should be imprvg Monday night into Tuesday as induced high pressure moves
into the middle Atlantic behind the departing vertically stacked low in
the Gulf of ME. Brzy conds expeceted Monday ngt/Tue. Skies should be on
the imprv during this time...W/ M sun expeceted Tuesday. Low pressure tracking
across the Gulf states Wednesday may spread clouds into the middle Atlantic but
pop chances will be low - best in the central shen vlly. Once the low
reaches the southeast CST it is expeceted to track slowly NE toward hat Thursday.
This will bring about a better chance for rain to the forecast area. Quantitative precipitation forecast would
The weak ahead will see high temperatures at or below the l70 late Apr climatology norms.
Looking deep into the Crystal Ball it looks lake warming could occur
the following weak.
Aviation /08z Sunday through Thursday/...
Area of rain spreads east to the south of District of Columbia metros this
morning...continued IFR conds for kcho through sunrise. Rain chances
shift south through the morning...also skies break from north to
south through the morning. North winds 5-10kt today...increase to 10
to 15 knots late tonight...becoming northwest Monday 15 knots gust 20 to 25 knots.
High pressure builds into the area Monday night through Wednesday. No concerns expeceted
aviation-wise. Low pressure tracking to the S may cause degradation in
North flow continued 7-12kt over the waters early this morning...15
knots late morning through this afternoon. Winds shift northwest late tonight
and increase...Small Craft Advisory for all waters Monday 15-20 knots with 25 knots
Small Craft Advisory conds likely Monday night and Tuesday.
District of Columbia...none.
Marine...Small Craft Advisory from 8 am to 6 PM EDT Monday for