Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 211100
Area Forecast Discussion
National Weather Service WAKEFIELD VA
700 AM EDT Tue Mar 21 2017
Low pressure dissipates across the area this morning with a
weak cold front passing through the area this afternoon. Low
pressure tracks across the Carolinas tonight and pushes off the
coast Wednesday morning. Canadian high pressure builds in from
the north Wednesday afternoon into Thursday, before drifting off
the coast Friday into Saturday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The current surface analysis shows broad weak low pressure
extending from SW VA to nrn VA, with a warm front extending into
SE VA, and a cold front approaching the wrn slopes of the
Appalachians. Aloft, a weak shortwave trough is tracking NW-SE
across the Mid- Atlantic. This is triggering some light showers
across the area. QPF is minimal and generally a few hundredths
of an inch. This activity is expected to diminish/dissipate by
12z. The cold front drops sewd through the morning and pushes
across the local area later this morning through the aftn. This
should result in continued mostly cloudy conditions, although
partial clearing is possible across the N the aftn. PoPs today
are <15% due to weak subsidence in the wake of the departing
shortwave trough. High temperatures range from the upper 50s/low
60s over the Ern Shore, to the low/mid 60s near the Chesapeake
Bay, 65- 70F farther inland across central/srn VA and interior
NE NC, and 70- 75F for the SW piedmont.
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Low pressure tracks across the Carolinas tonight through early
Wednesday morning as a cold front arrives from the N. 21/00z
models have continued to trend swd with this feature, so PoPs
have been lowered to 20-40% across Srn/SE VA/NE NC, and <15%
along and N of a FVX-RIC-WAL line. Drier/cooler air arrives with
a gusty NNW wind Wednesday as 1036-1038mb high pressure builds
from the Great Lakes into the nrn Mid-Atlantic. Lows tonight
range from the upper 30s N to the mid 40s central/SW. Highs
Wednesday range from the mid/upper 40s across the Ern Shore to
the low/mid 50s farther inland with cloud cover decreasing from
NW-SE during the morning hours. A NNW wind will increase to
15-25mph Wednesday, with gusts up to 30-35mph possible,
especially near and along the coastlines.
1038mb high pressure becomes centered from central PA to nrn VA
Wednesday night, with some pressure gradient/weak CAA lingering
near the coast. Mostly clear and colder with lows ranging from
the low 20s across the N to the upper 20s/around 30 for coastal
SE VA/NE NC. These values are generally 10-15F below seasonal
averages. The high becomes centered over the region Thursday and
remains ~1036mb. Mostly sunny and cool with highs ranging from
the low/mid 40s over the Ern Shore to the upper 40s/around 50F
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Ridge axis over the region allows for a cold night Thursday
night. Lows in the upr 20s-lwr 30s. The high moves off the Mid
Atlantic coast Friday through Saturday allowing temps to quickly
warm. Highs Friday in the mid 50s-lwr 60s. Lows 45-50. Highs
Saturday in the mid-upr 60s along the coast, upr 60s-lwr 70s
west of the Ches Bay.
Moisture starts to increase ahead of an approaching frontal boundary
Saturday night and Sunday. Low chc pops Sat night. Lows in the upr
40s-lwr 50s. Frontal boundary progged across the region Sunday and
Sunday night. Mild with chc pops (slght chc thunder across the
south). Highs upr 50s-lwr 60s Eastern Shore areas, mid-upr 60s
west of the Bay. Lows in the upr 40s-lwr 50s. Lingering
moisture keep chc pops going into Monday. Highs in the 60s.
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --Weakening low pressure and an associated cold front push into
the region early this morning. Sct -shra accompany this system
along with 6-8kft cigs. These -shra will quickly depart and
dissipate by 12z. The cold front drops through the region
roughly between 15-21z today producing a wind shift from SW-NNW.
Bkn VFR cigs ~6-8kft are expected to prevail today, but could
become sct at SBY by aftn. The cold front stalls across the
Carolinas tonight with low pressure tracking along the boundary.
Current trends are to shift this system swd, so there is only a
30-40% chc of -ra across far SE VA/NE NC mainly between 06-12z
tonight/Wednesday morning. A stronger cold front pushes through
early Wednesday as low pressure pushes offshore. A N wind will
increase to 15-20kt with gusts up to 25-30kt Wednesday. High
pressure builds in from the NW Wednesday aftn and settles over
the area Thursday. The high then slides offshore Friday and
settles off the Southeast coast by Saturday.
-- End Changed Discussion --
Latest surface analysis depicts weak low pressure over eastern
Kentucky, with a frontal boundary extending eastward into
southeast Virginia. High pressure centers over the Bahamas is
ridging northward along the Southeast coast. The result is a
south wind of 5- 10 knots over the local waters. Long period
northeast swell continues to produce elevated seas, ranging from
3-4 feet north of Cape Charles light to 4-5 feet south. SCA
conditions persist through mid morning as swell periods
decrease. The weak area of low pressure lifts into the region
today as the front pushes offshore. Winds become north to
northwest around 10 knots this afternoon. Seas subside to 2-4
feet. The low pushes offshore late today as another area of low
pressure develops over North Carolina. The North Carolina low
pushes offshore tonight as strong Canadian high pressure builds
southward over the Great Lakes region. A strong north-northwest
surge is expected over the waters late tonight as cold air
advection spreads over the waters ahead of the strong high.
Speeds increase to 20-25 knots with gusts to 30 knots early
Wednesday morning. Based on the strong pressure rises ahead of
the high, there is a potential for low end gale conditions in
the bay and coastal waters. However, boundary layer winds are
progged only around 30-33 knots. Will stick with solid SCA
conditions for the Bay and coastal waters beginning early
Wednesday morning, with the strongest winds centered a few hours
around mid morning. Northwest winds diminish to 15-25 knots
Wednesday afternoon. Seas build to 4-6 feet Wednesday and waves
2-5 feet. The high builds over the Ohio Valley Wednesday night,
with ongoing SCA conditions in the Bay/Sound/Coastal waters with
winds of 15-25 knots. Seas subside to 3-5 feet by late
Wednesday night. Waves 2-3 feet, with a few 4 footers possible
in the mouth of the bay late. High pressure builds across the
waters Thursday, bringing sub-SCA conditions back to the waters.
Return flow expected Friday as high pressure slides offshore.
The next front pushes across the waters early next week.
Radar KDOX remains inoperable due to a bad spectrum filter.
Part is on order and estimated (though possibly unstable) return
to service is Wednesday, March 22nd.
MARINE...Small Craft Advisory from 10 AM to 6 PM EDT Wednesday for
Small Craft Advisory from 6 AM Wednesday to 6 AM EDT Thursday
Small Craft Advisory until 10 AM EDT this morning for ANZ656-