Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
448 PM EDT Monday Aug 31 2015
low pressure slides off the Carolina coast tonight. Weak high
pressure then persists over the area through the end of the week
with occasional weak troughs of low pressure.
Near term /until 6 am Tuesday morning/...
latest surface analysis reveals a weak trough of low pressure near the Carolina
CST with broad hi pressure over the Ohio/Tennessee valleys. An area of rain showers
associated with the front and a passing middle-level shortwave trough
will continue over the next few hours over NE NC...before
dissipating tonight as drier air works its way into the region. With
the front in the vicinity...did hold onto some slight chance probability of precipitation
overnight for extreme southeast Virginia/NE NC but dry weather will prevail area-wide
as surface hi pressure nudges into the area from the west. Skies will range from
mostly clear northwest to mostly cloudy southeast. Some fog is possible but not likely
since clouds are expected to persist in the areas that received
rain today. Overnight low temperatures in the upper 60s to lower 70s.
Short term /6 am Tuesday morning through Thursday/...
short term period will be characterized by weak surface hi pressure on average
with an occasional weak trough of low pressure developing over the middle
Atlantic. For Tuesday...decreasing moisture profiles and weak forcing for
ascent will yield mainly dry conds...with at best a slight chance
of a rain showers/thunderstorm over southern portions of the forecast area. With rising middle-level
thicknesses...temperatures will be warmer than the previous few days and
maximum out near 90 in most areas...about five degrees above normal.
A weakening middle-level shortwave trough approaching from the west Wednesday afternoon
will lead to a slight chance-chance of shras/tstms...with the best
chance over western areas. Moisture profiles do not favor widespread
heavy precipitation. Similar probability of precipitation into Thursday with a weak surface trough over the
region and little upper-level support. Temperatures maximum out in the low 90s
most areas Wednesday and Thursday...mid/upr 80s near the CST. Overnight low temperatures
in the upper 60s to lower 70s.
Long term /Thursday night through Monday/...
extended period begins with a backdoor front moving across the area
on Friday...resulting in surface high pressure over the NE US
ridging south. The ridging will help to moderate temperature and
humidity through the weekend due to the NE to east flow. Weak middle level
troughing off the southeast will help generate showers and thunderstorms to
our south...but as the ridge at the surface and aloft builds over
the area...precipitation will be suppressed to the south of the akq
Forecast highs in the middle 80s inland and lower 80s near the coast
Sat through Monday. Low temperatures will range from the middle 60s to upper 60s
across the area.
Aviation /21z Monday through Saturday/...
latest regional radar mosaic depicts scattered light
showers over southeast Virginia and northeast NC moving northeast
primary across ecg and close to orf. Based on radar trends and
model guidance most of the precipitation should be off the coast by 4
PM. For the most part middle and high clouds covered areas from sby
to ric and roa south with just a few locations reporting MVFR
conditions. Clouds were beginning to break up across central Virginia
however a broken deck between 5kft and 8kft will persists. Ceilings
of 3kft to 7kft will persists at orf and ecg through the
afternoon gradually improving this evening. Generally the low and
middle- level deck of clouds across the southeast is expected to
break up late this evening. Other concern will be the chances for
IFR conditions overnight due to fog/stratus at ric...orf and ecg.
Some guidance is suggesting IFR fog less than 2 miles and
ceilings 1kft or lower between 08z-13z...but with high pressure
remaining over the region and potential cloud cover will hold off
on going to pessimistic in tafs.
High pressure prevails through the end of the week. Only isolated
to widely scattered showers/thunderstorms are possible across the
region each afternoon. Dewpoints warm into the upper 60s to around
70...resulting in patchy early morning ground fog.
weak area of high pressure remains over the local waters with the
center of the high offshore. The result is southerly flow at or below 10 knots.
Seas 2 feet in the north and 2-3 feet south. Waves across the Bay 1-2
feet. A slight strengthening of the gradient tonight will push speeds
to 10-15 knots. Weak area of low pressure forms off the Carolina coast
on Tuesday resulting in variable wind directions through Wednesday. Seas
generally 2 feet and waves 1-2 feet. High pressure weakens over the
region Friday...as another area of high pressure builds southward over New
England. Prolonged NE flow may bring potential Small Craft Advisory conditions during
the upcoming weekend as seas could build 4 to 5ft.