Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
855 PM EDT Wednesday may 27 2015
high pressure remains anchored well off the middle Atlantic coast
through Thursday...with a trough of low pressure nearly
stationary east of the mountains. High pressure will build over
the northeast states Friday...then slide off the coast Saturday.
A slow moving cold front will enter the local area from the
northwest later in the weekend.
Near term /until 6 am Thursday morning/...
Summer-like afternoon across forecast area...most inland temperatures in the M/u80s west/
u70s-l80s closer to the shore (although Ocean City beaches stuck
around 70f). P/mostly sunny...W/ south-southwest winds gusty to 20-25 miles per hour. Cumulus has
a little more vertical development as compared to past couple of
days...but SBCAPE generally at or below 750 j/kg (w/ no trigger). Atmos remains
just warm/stable enough for more widespread convective
development...and should remain so through the evening hours. Will carry
20-30% probability of precipitation across forecast area...holding probability of precipitation at or below 14% at the shore. Isolated
rain showers may linger overnight...otherwise another round of scattered-broken strato-cumulus
expected after 06-08z/28. Low temperatures from the u60s-l70s.
Short term /6 am Thursday morning through Saturday/...
persistence generally continuing on Thursday...though model soundings do hint at a
bit higher SBCAPE/MLCAPE (agn away from the cst) by afternoon. Will have
vrb clouds/mcldy to start the day...then avgg out psny...warm again
west/ 30-40% probability of precipitation inland...20% at the shore. Lclly heavy downpours
will be possible along west/ brief gusty winds from any storms. Hi temperatures Thursday in
the M/80s...W/ exception to 70s at the shore.
Weak surface hi pressure slides east across new eng Friday. Models show a slight drop in
dewpoints across far north-northeast counties for the day...while remaining up elsewhere. Hi
pressure just offshore begins to slightly build westward during the day...so
focus of higher probability of precipitation (30-40%) northwest 1/2 of forecast area (10-20% probability of precipitation elsw). By
Sat...cold front from the northwest approaches...though remains far enough away for
any effect on the weather here. Will keep conds warm west/ vrb
clouds/pcldy and 15-25% probability of precipitation inland...10% at the CST. Hi temperatures Friday
and Sat in the M/u80s inland...70s at the CST. Low temperatures m60s- around
Long term /Saturday night through Wednesday/...
the medium range period remains characterized by middle/upper level
ridging over the eastern Continental U.S. With a trough lingering over the
intermoutain west. Surface high pressure builds across eastern Canada
Saturday night and Sunday pushing a cold front into the northern middle
Atlantic. 12z GFS/European model (ecmwf) diverge Sunday night/Monday with the GFS
bringing the surface cold front through the local area Sunday
night and the European model (ecmwf) waiting until Monday. High pressure settles in
vicinity of the New England coast Tuesday and Wednesday...and
moves offshore Thursday. The best focus for convection appears to
be Sunday afternoon/evening ahead of the cold front with 40-50%
probability of precipitation forecast across the northern half of the area. The wind profile
will remain weakly sheared so any thunderstorms should be rather
unorganized. Probability of precipitation Monday afternoon and evening are forecast to be
30-40% Monday afternoon/evening...and then trend downward to
20-30% by Tuesday and sub-15% through midweek as surface high
pressure prevails. High temperatures Sunday are forecast to range
from the middle to upper 80s...with upper 70s to low 80s behind the
front Tuesday through Thursday. Lows should average through the
Aviation /01z Thursday through Monday/...
hi pressure has centered well off the northern middle-Atlantic CST this evening...with
a cold front pushing through the Great Lakes region into the Ohio Valley.
This was resulting in continued S-SW winds. Widely scattered
showers/thunderstorms over the Piedmont of Virginia/NC will weaken and dissipate
tonight. MVFR/VFR ceilings and visible possible at taf sites Thursday morning
due to moist environment.
Cold front will approach the northwest/northern counties on Thursday...before
washing out. Hi pressure sets up off the northern middle Atlantic CST Friday through
Sat...with another front approaching from the northwest/north late Sat/Sat night.
Diurnally driven showers and thunderstorms possible Thursday through Sat.
Otherwise...mainly VFR conditions will prevail outside of thunderstorms.
high pressure remains centered off the middle Atlantic coast through
Saturday. A weak trough tracks well north of the region tonight...and
then a weak cold front drops into the northern middle Atlantic Thursday
night. A south-southwest wind could briefly reach 15-20kt across the Bay late
this afternoon and evening. Otherwise a south-southwest wind should average
at or below 15kt through Thursday. The gradient will slacken Thursday
night into early Friday allowing the wind to become south-southeast at or below
10kt...although a wind shift to the NE with the aforementioned
front will likely remain north of the region. High pressure shifts
farther offshore Saturday as a cold front moves into the Great
Lakes. This will allow the wind to increase to 10-15kt (15-20kt
ocean). The aforementioned cold front slowly approaches the region
and moves through the area Sunday night into Monday.