Scientific Forecaster Discussion
fxus61 kakq 221426
Area forecast discussion
National Weather Service Wakefield Virginia
1026 am EDT Tue Oct 22 2019
a cold front will cross the region late this afternoon and this
evening. High pressure returns Wednesday and Thursday. Another
cold front crosses the area over the upcoming weekend, bringing
another chance of rain.
Near term /until 6 PM this evening/...
as of 1025 am EDT Tuesday...
The forecast area remains socked in under low clouds attm and most of the
near term hi res guidance suggests any improvement will be very
slow into/through this afternoon. Highest prob for significant
is across far southeast Virginia-NE NC but even there it appears it would
takes some time in most of that area (into this afternoon). Cold
front from the west will continue to approach the rest of the day.
Shras now west and SW of the forecast area will continue their March to the
east-northeast. Highest quantitative precipitation forecast (into this evening) looks to be confined to northwest
1/2 of the forecast area. The model trends show that the bulk of the pcpn
passes to the north in association W/ the better mid-upper level
dynamics. Most of the forecast area will remain under a stable atmosphere
W/ only far southeast Virginia-NE NC potentially getting into a bit of
instability by late afternoon/early this evening. Have kept slight
chance T for srn/southeast Virginia-NE NC but coverage will likely be quite
limited (and generally non-sfc based). Severe threat looks minimal
but slight risk remains nr/S of the Virginia-NC border (w/ primary threat
from any of the possible stms being strong/damaging wind gusts)
where Theta-East Ridge does manage to poke NE towards those areas.
Typical wedge orientation wrt temps. Highs in the l-m60s
northwest...m60s-around 70f I 95 corridor and east...70-75f southeast Virginia-NE NC.
Short term /6 PM this evening through Friday/...
as of 345 am EDT Tuesday...
Showers taper off as cold front slides offshore early this
evening. Becoming breezy Post-frontal this evening, which will
keep temperatures from realizing true radiating potential. Will
carry light pops west of the Bay thru 06z along the coast in
expectation of some more lingering light rain/dz. Decreasing
cldns west-east aftr midnight. Lows in the 40s west of the Bay, 50-55
near the water.
Cooler and drier for Wed/Thu, as cool high pressure builds
in from the west-SW Post-frontal and becomes centered over the
local area on Thu. Highs in the mid 60s to around 70 on
Wednesday, and in the upper 60s to low 70s on Thursday. Chilly
early morning lows in the upper 30s to mid 40s Wed night.
Split decision with models for Friday...non-NCEP models
(canadian (cmc-global)/European model (ecmwf) each a bit slower with the next
front, and therefore keep the area dry Friday into the weekend.
GFS has been much more aggressive with this feature. However,
given strong ridging building upstream in the Pacific northwest (and a
subsequent downstream trough in the desert southwest), would
like to hedge toward the slower, more amplified solution rather
than the flatter, more progressive GFS. Accordingly, have played
the pops slower and kept Friday dry, with a low chance of rain
by Friday night and Saturday. Highs remaining mainly in the mid
to upper 60s...around 70 southeast.
Long term /Friday night through Monday/...
as of 345 am EDT Tuesday...
The long term period will begin with a weak high pressure
system over the area Friday night. Keeping the area dry with
seasonable cool temperatures. At the same time, an upper level
trough will be digging south east of the Rocky Mountains. After
this point, the GFS and European model (ecmwf) differ greatly. The GFS continues
to move the upper trough east and push a cold front through the
mid-Atlantic with wide spread rain for Saturday. While, the
European model (ecmwf) and Canadian models cut off an upper low over West Texas
and northern Mexico with a shortwave moving across the Great
Lakes and northeast US. This will push a weak front through the
area with little to no precip Saturday. The GFS bring in a
strong sfc high pressure in for Sunday with much cooler
temperatures. While, the European model (ecmwf) and Canadian shows a trough
diving south along the West Coast which will kick the upper low
over Texas/northern Mexico to the northeast.
Leaning heavily towards the European model (ecmwf) for the extended forecast.
With little to no rain through Sunday morning. Light rain
showers will may move back into the area for Sunday afternoon as
the upper low tracks west of the Appalachian Mountains and into
the eastern Great Lakes. While the low pressure system tracks
west of the mountains a wedge will likely develop over eastern
VA, MD, and the NC Piedmont with a sfc high centered over New
England. This will keep clouds over the area with cooler
afternoon temperatures for the weekend, while overnight lows
will be warmer with the cloud cover and onshore flow.
With the European model (ecmwf) solution, high temperatures will be in the upper
60s for Friday and lows in the low to mid 40s (50 for coastal
Hampton Roads and NE nc). Behind the weak cold front that will
move through Saturday, highs will remain in the low 60s with low
temperatures in the 40s once again. Sunday highs may struggle to
reach the low 60s (mid 60s near the Virginia and NC coasts) with a
wedge developing and overnight lows range from near 50 degrees
northwest of Richmond to near 60 near the coast.
Aviation /14z Tuesday through Saturday/...
as of 715 am EDT Tuesday...
Low cloud deck lingering in place, bringing IFR-LIFR conditions
inland, with MVFR conditions along the coast. Conditions may
improve to low end VFR briefly by late morning but will likely
remain MVFR with even some breaks in the clouds for Hampton
Roads and NE NC. Cold front will approach the area by the
afternoon. Cigs will likely drop back below 1000 ft as the front
passes for kric and ksby. Southeast Virginia and NE NC cigs will drop as the
front passes as well, but should remain 1-2k ft. Rain showers
are also like during the afternoon with the front. Low
confidence on thunder forecast, and hv held thunder mention out
for now, with best chc at orf/ecg after 20z/4p. Winds will be
light and variable tonight. On Tuesday, winds will begin southeast 7-15
kt then turn SW 5-10 kt behind the frontal passage.
high pressure builds into the area for the midweek period.
as of 345 am EDT Tuesday...
Early this morning, an area of high pressure is situated over the
waters allowing for light and variable winds. This area of high
pressure will continue to drift further offshore, with winds backing
to the S and southeast later this morning. A strong cold front approaches
from the west through the day, before crossing the waters tonight.
Out ahead of the front, winds will be on the increase with gusts of
20 to 25 knots likely by this late afternoon/evening. As a result,
small craft advisories are now in effect for the Chesapeake Bay
beginning at 20z and lasting into Wednesday morning. In addition,
hi-res model guidance continues to indicate a line of showers
and potentially storms crossing the waters ahead of the front
during the evening hours. Behind the front, winds turn to the northwest
at around 15 to 20 knots, with some gusts to 25 knots possible
over the Chesapeake Bay and coastal waters. High pressure builds
back over the region by Wednesday afternoon and winds diminish
over the waters.
Seas will likely remain in the 4 to 6 foot range into Wednesday. As
a result of the elevated seas (and potential for 25 knot wind
gusts), have extended the scas for all coastal zones into Wednesday
morning. Scas for the coastal waters may need to be extended into
Wednesday afternoon or evening as seas will likely be slow to
as of 400 am EDT Tuesday...
Coastal flood statements and advisories are now in effect for
areas adjacent to the Upper Bay for the upcoming high tide.
Anomalies have continued to rise early this morning across the
Upper Bay, coming in around a foot to a foot and a half. This
will allow for locations along the tidal Potomac and Upper Bay
to approach minor flood thresholds later this morning. S to southeast
winds increasing ahead of a cold front will allow for anomalies
to remain high into the evening tidal cycle, thus additional
coastal flood headlines will likely be needed.
Maryland...coastal flood advisory until 11 am EDT this morning for mdz021.
Marine...Small Craft Advisory from 4 PM this afternoon to 7 am EDT
Wednesday for anz630>632-634.
Small Craft Advisory until 7 am EDT Wednesday for anz650-652-