Scientific Forecaster Discussion
fxus61 kakq 211037
Area forecast discussion
National Weather Service Wakefield Virginia
637 am EDT sun Jul 21 2019
high pressure remains centered across the southeastern states
through Monday. A strong cold front crosses the area Tuesday,
with high pressure building in from the north Wednesday through
Near term /until 6 PM this evening/...
as of 300 am EDT Sunday...
Heatwave rolls on today. There is slight weakening of hi pres
sfc-aloft by later today and that may allow for a better (though
very subtle increase) probability for tstms (esp over the piedmont).
Otw...dew points will remain a challenge this package. SW winds
likely to avg a bit higher by this afternoon which may result in
a bit higher temperature and slightly lower relative humidity. Maintaining
excessive heat warning (ehw) for heat indices 105-115f over the
forecast area (highest I 95 on east to the coast). Finally...like
yesterday...one or 2 stray tstms may pop over central/eastern
areas but will keep pops blo 10% those areas. Highs today
Short term /6 PM this evening through Tuesday/...
as of 315 am EDT Sunday...
Still very warm/humid tonight. Pops mainly aob 15% (a bit higher
across the nrn tier of the fa). Ridge aloft breaks down further
Mon and a cold front slows its approach from the northwest. Another
hot day...though the heat will likely be trimmed over northwest
portions. Highs northwest 90-95f...while another day of u90s-around
100f likely...esp southeast Virginia-NE NC. A heat advisory will likely
replace the current ehw along and east of I 95 as SW winds will be
gusty to 20 mph (helping to mix out/lower dew points at least a
little bit more). Pops increase to 30-40% northwest and aob 20% southeast by
late Mon afternoon/evening...though some of the model guidance
still shows the front roughly 3-6 hours slower in arriving (late
The heatwave will come to an end Mon night-Tue as the cold front
finally crosses the forecast area and exits (late Tue/Tue night). Pops will
increase to about 80% by late Mon night and then be slow to
taper from northwest to southeast through Tue (evening). Scattered strong tstms
possible initially as the cold arrives (late mon)...then the
emphasis will change to the potential for locally heavy rain (esp
east and southeast tue). Lows Mon night from the u60s-around 70f northwest to the
M-u70s southeast. Mostly cloudy and cooler W/ north-northwest winds a bit gusty
(esp at the coast). Highs in the 70s to l80s (far se).
Long term /Tuesday night through Saturday/...
as of 345 PM EDT Saturday...
The upper trough and associated cold front slide southeast of the
area late Tuesday through Wednesday. Both the GFS and European model (ecmwf) are in
fairly good agreement with the timing of the frontal passage, with
the majority of any precipitation coming to an from northwest to southeast through
the day on Wednesday. The front likely lingers just to the southeast of the
area late Wednesday into Thursday. As a result, have a slight chance
for a shower or storm across the far southeast into the day on Thursday.
High pressure will be building in from the north behind the front,
leading to drier conditions across the entire region late this week
and into next weekend. Wednesday will start out as the coolest day
of the forecast period with highs in the low to mid 80s across much
of the area. Low temperatures will dip back into the 60s with even
some upper 50s across the northwest Wednesday night. A gradual warming
trend is anticipated Thursday and Friday with temperatures climbing
back into the mid to upper 80s. Overnight lows will also trend
warmer with values in the mid to upper 60s (lower 70s along the
Aviation /12z Sunday through Thursday/...
as of 635 am EDT Sunday...
VFR conditions expected through the 12z taf forecast period.
Strong hi pres sfc-aloft will stay anchored off the coast into
Mon W/ SW 5-15 kt (maybe a bit gusty this afternoon/evening) and
few-scattered cumulus generally between 16-23z/21. While an isolated tstm is
possible...coverage once again would be very limited. A bit
higher probability for shras/tstms by late Mon-Mon night as a cold
front enters the region from the northwest. That front will be slow to
exit through Tue. Flight restrictions are expected mainly due to
lowered vsbys in storms. VFR conditions expected by Wed-Thu.
as of 400 am EDT Sunday...
No headlines in the short term today thru Mon, but may need
sca's for the Currituck snd Mon night, and the nrn three coastal
zns Mon night into Tue morning. Early this morning, strong high
pressure at the surface and aloft remains anchored well off the
southeast coast, providing SW or west winds 5-15 kt over the waters.
Waves were 1-2 ft, and seas were 2-3 ft.
South-southwest winds mainly 5-15 kt will continue today thru Mon, as high
pressure remains well off the southeast coast while a cold front starts
to approach from the northwest. Large scale ridging will break down on
Mon, as a surface trough precedes an upper level disturbance
approaching from the Great Lakes. SW winds will increase as the
pressure gradient begins to tighten Mon aftn into Mon night,
generally 10-20 kt over the waters, highest in the srn ches Bay,
Currituck Sound and coastal waters. Waves will build to 2 to 3
ft, while seas will build to 3-4 ft S, and 4-5 ft in the nrn
three coastal zns. A period of showers and storms will accompany
the surface trough Mon evening into the overnight, with the
potential for strong winds and locally higher waves/seas. A cold
front will then drop across the waters Tue into Tue evening,
with winds shifting to the northwest or north around 10 kt behind the
boundary into Wed morning.
for today Sat 7/20: no record highs were broken or tied at the 4
main cli sites, but pending a significant temperature drop
through midnight lst, ecg will have a new record high min at 79
and orf will have tied their record high min at 79. Good chance
for several record high mins to be tied or broken for sun 7/21.
Record highs and record high mins are listed below:
* richmond: record high record high min
* Sat (7/20): 103/1930 78/2013
* sun (7/21): 104/1930 77/1930
* Mon (7/22): 103/1952 79/2011
* norfolk: record high record high min
* Sat (7/20): 102/1942 79/1977 *today low so far 79f
* sun (7/21): 101/1926 80/1983
* Mon (7/22): 102/2011 82/2011
* salisbury: record high record high min
* Sat (7/20): 104/1930 83/2013
* sun (7/21): 106/1930 77/2017
* Mon (7/22): 104/1930 80/2011
* eliz city: record high record high min
* Sat (7/20) 104/1942 78/2012 *today low so far 79f
* sun (7/21) 102/1987 79/1983
* Mon (7/22) 104/1952 79/2011
Maryland...excessive heat warning until 11 PM EDT this evening for
NC...excessive heat warning until 11 PM EDT this evening for
Virginia...excessive heat warning until 11 PM EDT this evening for vaz048-