Scientific Forecaster Discussion
fxus61 kakq 221937
Area forecast discussion
National Weather Service Wakefield Virginia
337 PM EDT Tue Oct 22 2019
a cold front will cross the region 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 am Wednesday morning/...
as of 255 PM EDT Tuesday...
St from earlier has generally lifted to broken-overcast cigs 1200-2500
ft inland and on the ern shore (except well west-northwest of ric over the
Piedmont where cigs remain blo 1000 ft)...sct-bkn higher cigs in
southeast Virginia-NE NC. Warmer/more humid air has made some progress north into
the forecast area this afternoon...but substantial clearing has been
reluctant to occur. Shras beginning to spread over more of
wrn/central portions now and that will continue far to the east-northeast
this evening ahead of an approaching cold front. A
narrow/shallow line of shras crossing the area may contain
brief heavy rain and gusty winds. Severe threat is limited at best.
The shras in the line now moving through wcentral Virginia only have
tops to about 12000 ft...not expecting much more dramatic
development far east this evening as near term hi res guidance
shows cape quite limited.
Cold front through the I 95 corridor by 00z/23 then off the
coast by 04-06z/23. Gusty south-southeast winds ern portions will last until
the frontal passage. Winds become west-northwest overnight resulting in
clearing. Lows from 40-45f west-northwest to the m50s at the immediate
Short term /6 am Wednesday morning through Friday/...
as of 225 PM EDT Tuesday...
Drier (not too much or any cooler) for Wed-Thu. Sfc hi pres
builds in from the west-SW Post-frontal and becomes centered over
the local area Wed night-Thu. Highs in the m60s to around 70f
Wed...then on Wednesday, and in the u60s-l70s Thu. Lows in the
u30s west-northwest to around 50f at the immediate coast Wed night.
Models continuing to struggle W/ wx for the end of the week
(fri). GFS/NAM quicker W/ return of moisture from the west-southwest while
the (00z/22) European model (ecmwf) was slower. Went W/ a blend of the
guidance...leaning slower W/ clouds and any pcpn during Fri.
Partly sunny becoming mostly cloudy (late) W/ highs mainly in
the M-u60s...l70s southeast.
Long term /Friday night through Tuesday/...
as of 330 PM EDT Tuesday...
The GFS and European model (ecmwf) still differ greatly in the long term. GFS keeps
an open trough moving across the southern plain into the southeast
US. While, the European model (ecmwf) cuts off a upper low across West Texas and
northern Mexico with a shortwave moving east across the Great Lakes
and northeast US. Therefore, the GFS was disregarded for the long
Using mostly the ECMWF, chance of precip will be near zero for
Saturday after the passage of a weak cold front. Sfc high pressure
will move in for Saturday with seasonable temperatures (highs in the
60s and lows in the 40s inland to 50 near the coast). Pops were
increased for Sunday (30-40%) as the upper low over Texas moves NE
into the western Great Lakes then into Ontario. This will likely
bring showers back into the region as warm southwest flow begins.
The European model (ecmwf) then forms an upper ridge along the Carolina and Georgia
coasts, with a sfc high pressure system off the Carolina coast for
the beginning of next week. This will keep temperatures mild for the
first half of the week, with highs in the low 70s and lows in the
50s. A slight chance of showers will remain in the forecast for the
beginning of next week as well.
Aviation /20z Tuesday through Sunday/...
as of 125 PM EDT Tuesday...
Broken MVFR-VFR cigs and south-southeast winds occasionally gusty to 20-25 kt
(esp at the coast) continuing into this evening ahead of an
approaching cold front. An area of shras will be tracking across
the forecast area...mainly from 20z/22 to 03z/23. A narrow line of shras
may contain brief gusty winds/heavy rain. A short period of
possible IFR cigs right after the cold front exits/pcpn ends
this evening then west-northwest winds bring drying overnight. High
pressure builds into the area for the midweek period. VFR
conditions Wed-Fri as sfc hi pres moves across the region.
Flight restrictions (from lowered cigs/vsbys and additional ra)
are possible by Fri night-Sat as lo pres tracks into the region
from the SW.
as of 330 PM EDT Tuesday...
Afternoon surface analysis shows deep low pressure over the u.P. Of
Michigan with a cold front extending southward to The Big Bend of
Florida. Another (much weaker) area of low pressure has formed along
the front across the Virginia/NC Piedmont. Southeasterly winds have
increased to 10-15 knots with gusts to 20 knots ahead of the
low/front. Waves are 1-2 ft and seas are running 3-5 ft.
Southeasterly flow will continue until the front crosses the waters
this evening. A narrow line of showers is noted along the front this
afternoon and hi-res guidance continues to show this feature into
this evening. Winds will be locally enhanced along this line and
could gust 25-30 knots as it passes. Otherwise, winds turn northwest 15-20
knots behind the front before slowly decreasing toward daybreak.
Waves will decrease to 1-2 ft but seas will stay near 4-6 ft through
Wednesday mid-morning. Current Small Craft Advisory headlines for the Bay extend
until 7am Wednesday morning with the offshore zones in effect until
High pressure builds in for the remainder of the week.&&
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.
Marine...Small Craft Advisory until 7 am EDT Wednesday for anz630>632-