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Area forecast discussion 
National Weather Service Wakefield Virginia
839 PM EDT Tue Sep 27 2016

a cold front stalls near the Virginia-North Carolina border tonight
through Wednesday morning. Low pressure tracks north across the
North Carolina and Virginia piedmonts Wednesday afternoon and
night. An upper level low slowly drops south from the Great Lakes
region resulting in unsettled weather conditions into the weekend.


Near term /until 6 am Wednesday morning/...
quick update to lower pops across interior portions of forecast area. Keeping
pops 50-70% from Virginia Eastern Shore to coastal NE NC until mid-late
evening. Partial clearing also will occur inland...especially
along-west of I 95 corridor.

Previous discussion:
latest msas showing the cold front basically splitting the fa in
half NE- SW. Band of convection ahead of it will continue to move
east and off the coast this evening. Pcpn has basically ended
across the Piedmont with partial clearing across wrn zones.

Boundary progged to stall along the Virginia/NC border tonight as low
pressure across the NC Piedmont begins to track NE after 06z. Pops
will be based off of radar trends but the jist will be for higher
pops this evening across the southeast. Some weak lift noted behind the
boundary after midnight so kept low chc pops. Attention then GOES
to fog development as the latest guidance is showing the potential
for widespread fog after midnight. Added areas of fog to the grids
after 06z. Lows in the 60s.


Short term /6 am Wednesday morning through Friday/...
interesting forecast for Wed and Wed nite. Potent S/W energy (triple
point low) progged to slowly track north along the i95 corridor.
After morning shwrs and areas of fog, expect nmrs shwrs and tstrms
to develop. The strength of the storms will likely hinge on whether
any sun will aid in heating. Storm Prediction Center has areas along and west of the i95
corridor in marginal risk with the threat being damaging wind gusts.
Locally heavy downpours are also possible. Will carry likely pops
after 18z. Highs from the mid 70s northwest to lwr 80s southeast. Lows in the mid
60s northwest to near 70 southeast.

Upper level (cut off) low progged to slowly sink south from the
Great Lakes region thurs then stall across Kentucky thurs nite before
beginning to slowly drift north-northeast Fri. Strong and persistant onshore
flow around this feature will add to the available moisture and cool
pool instability to produce widespread showers with embedded tstrms.
Upslope conditions will likely produce pockets of moderate to heavy
rainfall across northern most zones on northward. Thus, kept chc to
likely pops going for most of thurs through Friday. Highest pops
across the north. Highs Thu in th mid 70s to lwr 80s. Lows in the
60sto near 70 southeast. Highs Fri 75-80.

Total quantitative precipitation forecast west of the ches Bay expected in the 2 to 4 inch range
with 1/2 to 1.5 inches along the coast. No flood headlines
anticipated at this time given the time frame that the rainfall
will occur over. Significant rises in river levels are possible
later this week if we do get the expected quantitative precipitation forecast across the headwaters.


Long term /Friday night through Tuesday/...
long term period starts off Fri night/Sat with an upper-level cutoff
low and associated sfc low centered over the Ohio Valley. Better rain
chances will stay north of the area, but included at least a 20-30%
chance of showers especially over NE areas where the highest
moisture will be located. Mainly dry conditions thereafter into sun
and Mon as the cutoff low weakens and slides NE into Canada. As for
temps, highs will generally be in the mid/upper 70s with lows
ranging from the mid/upper 50s over the Piedmont to the mid/upper
60s near the coast.


Aviation /01z Wednesday through Sunday/...
a cold front has continued to slowly push through the region and
is now located near the coast. IFR conditions continue to be
present at sby due to residual showers/lower ceilings (600ft),
added a tempo group for to take account for this. Also added a
tempo group at ric for the possibility of lower ceilings over the
next few hours. VFR conditions are expected at the remaining taf
sites for the first half of the night.

Tricky forecast is in store for the rest of the night with
the potential for fog across the area. Introduced IFR conditions
by 04z for sby and 06z for ric due to highest confidence of fog
potential. Brought MVFR into all other taf sites. Model guidance
still hints atthe potential for some locally dense fog towards

Next batch of precipitation will approach the Piedmont as
low pressure along the front begins to move north later
tonight. Introduced vcsh at ric after 06z due to some uncertainty
with initial timing and coverage of the showers.

Outlook: unsettled weather conditions expected through the end
of the work week as waves of low pressure lift along the cold
front. Showers with late day thunderstorms will be possible each


latest sfc analysis shows a stalled frontal boundary over the local
area. The frnt remains in the vicinity through Wed leading to sub-
sca conditions with 1-2 ft waves over the Bay and 2-4 ft seas over
coastal waters. The front then lifts northward Wed night/Thu, and
with strengthening high pressure over southeast Canada/New England, seas
will ramp up. Hoisted a sca for the northern coastal waters for Wed
night/Thu with prolonged easterly fetch, which may need to be
extended past the fourth period in future updates. 5 ft seas may
also possibly affect the southern coastal waters as well. Overall
winds will avg 10-15 kt through the period, up to 15-20 kt over
northern coastal waters at times.


Akq watches/warnings/advisories...
Marine...Small Craft Advisory from 7 PM Wednesday to 7 PM EDT Thursday
for anz650-652.


near term...alb/mpr
short term...mpr
long term...mas

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