Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
1024 PM EDT Monday Jul 28 2014
a cold front will push off the coast tonight into Tuesday. High
pressure will build into and over the area from the northwest
for Tuesday through Wednesday...then slides offshore for Thursday.
Frontal boundary will drift back toward the middle Atlantic coast
Friday through Saturday.
Near term /until 6 am Tuesday morning/...
latest surface analysis places cold front off the middle-Atlantic coast
this evening with the parent low centered over ME. In wake of the
front...winds have subsided due to relaxing pressure gradient.
Skies have also cleared in westerly flow aloft. Anomalous middle-level
longwave trough (-3 Standard dev 500 mb heights) will continue to settle
over the eastern Continental U.S. Tonight...ushering in a cooler/drier airmass.
Low level thickness values prognosticated to drop nearly 30m by Tuesday
morning. The result will be slightly below normal low temperatures with
lows generally in the lower to middle 60s. Warmer along the coast
with lows in the upper 60s. Current forecast is on track with
little changes made overnight.
Short term /6 am Tuesday morning through Thursday/...
dry and rather pleasant Tuesday and Wednesday (esply tue)...as surface hi pressure
builds into and over the area...despite longwave trough digging
(sitting) over the middle Atlantic region. An isolated shower or thunderstorm could
occur over NE NC Tuesday afternoon...as the base of the upper level trough swings
through the region and interacts with a weak surface low lingering just
off the NC CST. Under a partly to mostly sunny sky...maximum temperatures
will range from the upper 70s to lower 80s. Generally mostly clear Tuesday
night with lows ranging from the middle 50s to lower 60s most places.
Partly to mostly sunny on Wednesday with highs in the lower to middle 80s.
Mostly clear Wednesday night with min temperatures ranging from the upper 50s to middle
60s. Hi pressure will be off the CST for Thursday...with east through S flow across
the area. Slight increase in humidity. Partly to mostly sunny with
maximum temperatures mainly in the middle 80s (maybe some upper 80s).
Long term /Thursday night through Monday/...
medium range period characterized by persistent upper level trough
over the eastern third of the Continental U.S.. beginning of the period stays
dry Thursday ngt/Friday...with some scattered (mainly diurnally driven) rain showers
expected over the weekend as the trough retrogrades back towards the
middle MS valley and a coastal front/inverted trough will locate
along/just off the mid-Atlantic/southeast coast. This will also
bring an increase in humidity through this same weekend/early next
week time frame. For temps, look for highs to remain at or below
climatology normal...generally riding into the l-M 80s. Early morning lows
generally in the 60s Sat morning, incrementally increasing to u60s
to around 70 by early Monday.
Aviation /02z Tuesday through Saturday/...
VFR conds over the County Warning Area. Strong low pressure system over New England
bringing west-northwest flow over the region. A cold front lies over the
Carolinas and high pressure will prevail through the next couple of days.
Winds will become north-NE overnight and Tuesday.
Outlook...dry weather is forecast through Friday. Mainly VFR is
expected although patchy MVFR/IFR fog could develop near sunrise
late tin the week. There will be a chance for showers and
thunderstorms over the weekend.
Note: observations from ksby are not readily available due to a
communications problem. Return to service is unknown at this time.
However...current information may be obtained by calling into the
ASOS site directly. Amend not schedule will be appended to the ksby taf
until further notice.
latest observation reflect west-SW flow 10-15 knots (15-20 knots in the lower ches
bay) out ahead of surface cold front which is presently dropping
south-southeast across the waters. Seas generally running 2-3 feet
this aftn, highest over northern waters. The cold front will the
waters early tonight, with winds veering around to the north-northwest after 00z
as modest cold air advection surge rides down the Bay. Winds could gust to Small Craft Advisory for
another couple of hours this aftn, but should drop below Small Craft Advisory briefly
late this afternoon and early this evening. Despite this lull, continued
Small Craft Advisory over the Bay and lower James until early Tuesday morning, with
the idea of winds slowly subsiding Tuesday morning. Will handle
wording of ramp up of winds in the mww/cwf.
Winds become onshore and diminish at or below 10kt as high pressure builds
in from the west through midweek. Stayed close to nwps, with onshore
flow keeping seas elevated around 2 to 4 feet. Coastal front/inverted
trough approaches from the east by the weekend, with winds veering
around to the S-SW late in the weekend with rain chances increasing
again over the waters.
Marine...Small Craft Advisory until 4 am EDT Tuesday for anz630>632-634-