Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
1015 PM EDT Monday may 25 2015
high pressure remains off the middle Atlantic coast through Saturday.
A trough of low pressure develops east of the mountains by middle week.
Near term /until 6 am Tuesday morning/...
Summer-like weather pattern continues west/ Bermuda hi pressure remains strong at this time.
Mainly light south-southwest winds overnight. Weak trough aloft moving into the southern mountains
this evening gradually dissipates as it tracks to the north-northeast through the
night. Sky clear east...and becoming pcldy west. Most low temperatures in the l/m60s.
Short term /6 am Tuesday morning through Thursday/...
Bermuda high continues the preview of Summer through the prd. Models
develop a Lee trough each day. Convection that develops over the mts weakens
as it moves east into the Piedmont Tuesday as airmass over most of the forecast area
remains capped. Kept 20-30 diurnal pop over the western most counties. Highs
in the M-u80s...m70s-l80s coastal areas...coolest at the beaches.
Latest models amplify the surface trough and are quicker to break the cap
which allows for a more eastward movement of the apprchg moisture from
the Ohio/Tennessee vllys both Wednesday and Thursday. Continued Summer-like but with
higher chances for mainly afternoon/evening showers/tstrms west of the ches Bay
Wednesday and as far east as the coastal areas Thursday. Given the increasing precipitable waters
and ll moisture...threats will be for lclly heavy downpours as steering
crnts remain weak. A tad cooler given more cloud coverage but with
more humidity. Highs both days in the l-m80s...xcpt 75-80 at the
beaches. Lows in the M-u60s.
Long term /Thursday night through Monday/...
the long term period will be characterized by above normal temperatures
each day and typical diurnal chances for thunderstorms...especially across
northwest areas. Upper level ridging will slowly break down during the
period. A cold front is expected to slowly approach from the northwest and
settle over the Middle Atlantic States by the end of the period. A
fairly dry period Friday and especially Saturday will be followed by
an increase of probability of precipitation to 40 to 50 percent Sunday and Monday. Probability of precipitation will
be lower over far southeast portions.
Guidance has 850 mb temperatures getting no higher than 16c. Cloud
cover...especially Sunday and Monday...will also hold readings down.
High temperatures are forecast to range from 85 to 90 inland and upper
70s to lower 80s near the coast. It will be moderately humid with dew
points in the middle to upper 60s. Lows temperatures are expected to be
in the 65 to 70 degree range.
Aviation /02z Tuesday through Saturday/...
high pressure off the middle Atlantic coast will provide stable
conditions and S/SW winds during the 00z taf period.
Winds be southerly Monday evening...increasing from the S/SW by
midday Tuesday. The sky will remain clear through Tuesday morning
with increasing high clouds by Tuesday afternoon.
Outlook...Bermuda high pressure will continue to dominate. The
combination of increasing moisture and a surface trough over the
Piedmont may produce scattered afternoon and evening thunderstorms
Wednesday through Saturday...mainly at ric/sby. The best chance for
convection will be Thursday. Outside thunderstorms...VFR conds should
latest surface analysis reveals strong hi pressure offshore with southerly flow
across the marine area. This stagnant weather pattern will continue through
middle to late week. Winds will average 10-15 knots...up to 15-20 knots over the
coastal waters each late aftn/eveng. Winds may come close to Small Craft Advisory criteria
over the Bay but have capped sustained winds for now at ~15 knots.
Waves over the Bay will be 1-3 feet with seas over coastal waters at 2-4
feet. There is a slight chance of rain showers/thunderstorms over the marine area
late in the week.