Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
423 am EDT Wednesday Sep 3 2014
a weak cool front drops through the area this morning...and washes
out near the Virginia...North Carolina border this afternoon. Weak high
pressure builds over the northeast states tonight...and settles
off the middle Atlantic coast Thursday and Friday. A more significant
cold front will approach from the west on Saturday...and slowly push
into the region Saturday night and Sunday.
Near term /until 6 PM this evening/...
latest weather analysis depicts a weak surface cold front pushing into
northern portions of the County Warning Area...with nearly zonal/westerly flow
noted at 500 mb. Isolated to widely scattered showers with a few
embedded thunderstorms are present on radar although cloud tops have generally
been warming per latest infrared satellite so the strength of storms
remains weak for the most part.
After record setting high temperatures across portions of the County Warning Area
yesterday (see updated climate section)...expect quite a bit more
cloud cover and low level flow turning though the North/East later this
morning to keep highs several degrees cooler (although still above
average for early sep). Generally went close to guidance with highs in the
upper 80s to lower 90s. Did this even though it was too cool
yesterday but this is probably due to such deep mixing of rather
dry aloft to the surface (something not likely today).
As for precipitation chances...have bumped probability of precipitation up later this morning to
high chance across far southeast Virginia/NE NC as the boundary approaches from the
north. Fro the afternoon...have expanded the 20% or higher probability of precipitation to
encompass all of the County Warning Area except for the Eastern Shore due to the
rather flat flow aloft likely inhibiting a deep push of drier air
from the north. Did go dry across the Maryland Eastern Shore where enough dry
air should push down on the southern edge of surface high pressure
centered over NY/PA. Will maintain highest probability of precipitation across the south
where highest instability/low level Theta-E ridging will reside.
Not much severe threat today due to limited shear but some locally
heavy rain possible across southern Virginia/NE NC due to precipitable
waters remaining high.
Short term /6 PM this evening through Friday/...
given continued warm/moist and marginally unstable air mass...will
maintain slight chance-low end chance probability of precipitation tonight/Thu...centered mainly
along the trough axis and Theta-E ridge over the southern local area.
Will see a lower rain chance on Friday with no discernible
convective trigger. However, will stick with a slight pop given
plenty of low level moisture and diurnal instability.
Highs remain nearly +1 Standard dev through the short term period,
generally around 90 to the lower 90s inland and slightly cooler
along the immediate coast. Mild overnight lows generally in the
upper 60s to lower 70s.
Long term /Friday night through Tuesday/...
long term period will feature a return to wetter conditions and
lower temperatures as an upper-level trough and surface cold front approach the middle
Atlantic. For Friday night/Sat morng...with the front still west of the
area expect dry conditions with increasing cloudiness and light S/SW
flow. Rain chances will increase through the afternoon hours Sat as the
front nears the area. Probability of precipitation range from 50% northwest to 20% far southeast. As the
front continues to progress into the region Sat night have bumped
probability of precipitation up to 50-60% all areas overnight with good moisture convergence
and lift noted along the front. Low temperatures Friday night in the upper 60s to
lower 70s with hi temperatures Sat in the upper 80s northwest to lower 90s southeast.
For sun...increased probability of precipitation to 50-60% as the front sags into southern VA/NC.
A (lwr) chance of rain will continue through early next week with the
front near the Carolina CST and waves of low pressure passing along the
front. As for temperatures...expect highs only in the upper 70s to middle 80s sun
and Monday with the chance of rain and cloud cover...and lows in the
middle 60s to lower 70s.
Aviation /08z Wednesday through Sunday/...
expect mainly VFR conditions at the taf sites today into early Thursday
morng. A weakening cold front will drop to near the Virginia/NC border
this morng into this afternoon...before dissipating. Meanwhile...the
center of hi pressure will slide by to the north today into Thursday morng. The
frontal boundary could trigger isolated or widely scattered showers or
Outlook...mainly afternoon and eveng showers and thunderstorms will be possible
the next several days. The highest chances will be on sun...as the
next frontal system moves through. Some MVFR/IFR conditions will be
possible within a few hours of sunrise.
no headlines in the short term today through Thursday night. Sub-Small Craft Advisory conditions
will continue this week and into the weekend. A weakening front
will drop through the Maryland/Virginia waters this morng and settle near the Virginia/NC
border this afternoon...veering winds from the SW-west to the N-NE. The center
of hi pressure will slide by to the north of the waters and off the CST
today through Thursday. Winds will shift from the east-southeast tonight to the S
everywhere by late Thursday. South-southwest winds less than 15 knots Friday through
Sat...then winds shifting to the north-northeast during sun...as a cold front
drops through the region.
record high temperatures set/tied yesterday Tuesday 9/2:
Ric: 100/1980 (new record established: 101 f)
orf: 97/1993 (new record established: 99 f)
sby: 97/1980 (tied record)
Richmond notable stats:
yesterday's high of 101 f Marks the 1st time ric has hit 100+ in
the month of September since Sep 11, 1983. Sep 1954 had the most
100+ days on record with 3 days. Sep 1970 had the most 90+ days on
record with 15 days (we have a long way to go to challenge this
Norfolk notable stats:
yesterday's high of 99 f is the hottest temperature recorded at orf
in the month of September since Sep 11, 1983 (when it also hit 99 f).