Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 250158

Area Forecast Discussion
National Weather Service Wakefield VA
958 PM EDT Tue Apr 24 2018

Low pressure tracks across Virginia late tonight...then will be
slow to move away from the coast Wednesday. Weak high pressure
returns by Thursday.


Late evening update as of 10 PM EDT Tuesday...

Latest MSAS has low pressure moving ne from the foothills of NC
and will continue to track ne across the local area overnight.
Rain of varying intensity continues to rotate north into the
area ahead of the low. High res data has backed off a bit on the
intensity of shwrs after midnite along the coast as the warm
front lifts north. In fact, data shows a bit of a dry slot
punching ne after 09Z along the coast. Thus, will continue with
high pops for the next several hrs then taper off a bit late.
Some drizzle and areas of fog across the Piedmont as the column
remains nearly saturated. Lows in the 50s to near 60 se.

.Afternoon discussion as of 4 PM EDT Tuesday...
On Wednesday, the initial surface low and warm front will lift
north of the area, but the upper level low will settle over the
area. This will allow for some cooler air aloft to settle over
the area with more showers developing in the afternoon. Could
potentially see some thunder if there is enough heating ahead of
the upper lows arrival. Right now, it looks like it will stay a
little too cloudy, but it can`t be ruled out especially east of
I-95. Guidance is pretty spread on temps tomorrow with the MET
much cooler than the MAV. Have generally gone in between with
temps in the mid 60s to the lower 70s.


As of 400 PM EDT Tuesday...

The upper low will exit the region early Wed night taking any
chance of rain with it. Show a gradual decrease in pops from SW
to NE during the evening. Behind this system the newer model
runs are not as aggressive in pushing the drier air with the
next sfc high into the region. This is more like what the GFS
had been depicting in previous runs. As a result have kept the
clouds a little longer and also raised overnight lows by a few
degrees getting closer to guidance in the low to mid 50s.

With the front not pushing as far south on Wed night into
Thursday and stalling more along the NC/VA border expect to see
a little less sunshine especially across srn VA/Nrn NC. The next
surface wave is now progged to arrive sooner on Thursday night.
So expect to see clouds on the increase during the afternoon and
could even see some light pcpn in the Piedmont counties around
sunset. At this point held off on adding late afternoon pcpn but
will need to see how quick the overrunning develops. For highs
on Thursday did have readings back into the low to mid 70s with
the best warming in the eastern portion of the CWA.

With the next wave arriving sooner have sped up pops on Thursday
night and Friday morning. The best chance for rain looks to be
in the Piedmont counties so have increased pops to 50 for now
and they may need to be increased. Once the surface low lifts
through the area by Friday morning should see the chances for
rain diminish by later morning/early afternoon. For
temperatures, kept readings a little warmer Thurs night with the
sw flow and clouds. For highs on Friday did keep highs in the
low to mid 70s as the return of the sun in the afternoon should
allow for temperatures to warm especially ahead of the cold
front for Saturday.


As of 400 PM EDT Tuesday...

GFS/ECMWF differ early in this period with the GFS showing the last
in a series of s/w trofs rounding the base of the long wave trof
late Fri night with it moving off the sern coast Sat ahead of a weak
frontal passage. Meanwhile, the ECMWF is drier with little if any
support for pcpn even with the frontal passage Sat. A model blend
results in low chc shwrs across the sern zones late Fri night and
Sat keeping the rest of the local area dry for now. Lows Fri nite
upr 40s-mid 50s. Highs Sat upr 60s-mid 70s, cooler at the beaches.

After that, some delightful spring weather on tap early next week as
high pressure builds se from the Gt lakes region Sun to a position
over the local area Mon then off the Mid Atlantic coast Tue. Cool to
start then a warming trend.  Highs Sun generally in the 60s. Lows in
the 40s to near 50 se. Highs Mon upr 60s-lwr 70s. Lows upr 40s-lwr
50s. Highs Tue 75-80.


As of 8 PM EDT Tuesday...

Low pressure will track ne across Virginia tonight. The steadiest
and heaviest rain has pushed north of the local area with widespread
IFR CIGS and lower VSBYS in both rain/fog continues thru the night
and into Wed morning. High res data even shows an enhanced band of
heavier shwrs (psbl thunder along the coast or just offshore) as the
associated warm front lifts northward along the coast btwn 04-10Z.
Gusty se wind 15-25 kts along the coast slowly diminish as the low
tracks ne. Ptchy fog west of the bay with some drizzle across the
Piedmont after midnite.

Upr level low then crosses the region Wed with the best support for
shwrs east of I95. Could also see an isltd tstm if enuf heating occurs.
Conditions finally inprove by Thurs as high pressure returns.

Another area of low pressure will impact the region Thursday night sct
showers and mvfr conditions. A second cold front swings across the the
region on Saturday with vfr conditions returning on Sunday as high pres
builds into the area.


As of 300 PM EDT Tuesday...

Broad low pressure is situated over Upstate SC this afternoon.
Meanwhile, high pressure is centered well off the New England coast.
The resultant pressure gradient between these two features is causing
east to southeast winds of 15-25 kt with gust up to 30 kt that will
last into this evening. Seas will continue to build to 6-10 ft by
this evening; waves reaching 3-5 ft, except up to 6 ft at the mouth
of the Bay. Winds/waves/seas diminish/subside overnight into
Wednesday morning as the pressure gradient relaxes. SCAs remain in
effect for all waters through late evening, with SCAs for the Rivers
coming down at 11 pm Tue, and for the Bay/Sound at 1 am Wed. SCAs
have been extended into Thursday morning for the southern coastal
waters and Thursday afternoon for the northern coastal waters due to
seas remaining elevated. A High Surf Advisory for OBX Currituck will
also remain in effect until 5 am Wednesday for nearshore waves of 8-
10 feet.

Broad low pressure lifts north through the region during Wednesday
with SSW winds 5-15kt becoming NW in the wake of the low Wed night
into Thurs morning. After a brief lull midweek the next low pressure
system then impacts the region Friday/Saturday.


NC...High Surf Advisory until 5 AM EDT Wednesday for NCZ102.
MARINE...Small Craft Advisory until 1 AM EDT Wednesday for ANZ630>633-
     Small Craft Advisory until noon EDT Wednesday for ANZ634.
     Small Craft Advisory until 6 PM EDT Thursday for ANZ650-652-
     Small Craft Advisory until 10 AM EDT Thursday for ANZ656-658.


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