Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
451 am EST Sat Feb 6 2016
high pressure settles over the area today...then moves off the
middle Atlantic coast tonight. Meanwhile...low pressure develops off
the Florida coast tonight...then intensifies while lifting northeast
along the southeast and middle Atlantic coasts Sunday through Monday.
Another area of low pressure will dive southeast from the Great
Lakes Monday...and move across the local area on Tuesday.
Near term /until 6 PM this evening/...
latest analysis indicating ~1031 mb surface high pressure centered
over southern Virginia and eastern NC. SW flow aloft bringing some high
clouds to the area but overall skies are mostly clear. Seasonably
chilly this morning with most areas in the 20s...although readings
are mainly in the 30s closer to the southeast Virginia/NE NC coast. For
today...dry/quit conditions will prevail with the surface high
remaining across the region...then drifting off to the NE and off
the Delaware-Maryland-Virginia later this afternoon. Due to the weak pressure gradient
there will be much less winds than yesterday...generally
light/variable this morning shifting to the S 5-10 miles per hour this afternoon
well inland (remaining onshore from the east/NE near the coast).
Highs today will average in the middle 40s along the coast and Eastern
Shore...to the upper 40s inland. BUFKIT soundings support partly
to mostly sunny skies today...with some middle/high clouds from time
Short term /6 PM this evening through Monday/...
partly cloudy/dry this evening across the local area. Models
continue to depict a deep upper trough (currently over east
texas)...pushing into the Gulf of Mexico tonight and tracking east
across Florida Sun morning. This will spawn anthr storm off the fla
coast tonight with explosive cyclogenesis prognosticated east of the
Carolina coast sun. The low continues to intensify as it tracks NE
along the coastal trough Sun night then well off to the east of the Virginia convective available potential energy
Monday. The latest NAM remains closer to the coast with the track
than the GFS/European model (ecmwf) consensus. Still appears to be mainly a
marine/wind impact for the akq County Warning Area...a major impact for marine
interests along the eastern Seaboard Sun night/Mon.
For sensible weather...will favor the somewhat drier solutions of the
GFS/European model (ecmwf) although even the NAM generally keeps northwest 1/2 of the County Warning Area dry
on sun. Grids will indicate chance probability of precipitation spreading NE along the NC
and southeastern Virginia coast through the day sun with chance probability of precipitation spreading north along
the Delaware-Maryland-Virginia Sun night. Critical thicknesses sprt precipitation type as
rain. Highs sun middle 40s in the clouds across the far southeast...to around
50 f farther inland. Lows Sun night 30-35 f...except 35-40 f along
the coast. The favored track suggests a little less wind than
previous forecast...but still should see strong / gusty north winds
along the coast with gusts up to 35-45 miles per hour sun and Sun night over
Virginia Beach / northern Outer Banks. Went ahead and addressed this in the
severe weather potential statement.
The ocean low departs to the NE Monday with the next systm quickly
diving southeast from the Great Lakes and Ohio vlly regions. Although there
probably will be a several hour prd of subsidence behind the departing ocean
low...moisture quickly increases west to east by afternoon. Will maintain chance
probability of precipitation most areas by Monday afternoon. As the moisture from the upper level low
crosses the mts. Precipitation type remains liquid with highs mainly 45-50 f.
Long term /Monday night through Friday/...
surface low pressure lifts NE well off the middle-Atlantic coast Monday
night into Tuesday. Meanwhile...a potent upper low continues to
dig southeast across the Ohio Valley Monday night...before heading
east into the northeast U.S. Tuesday into Wednesday. Thermal
profiles appear cold enough for snow showers or rain/snow showers
Monday night/Tuesday...and perhaps lingering into Wednesday across
northern areas. Have adjusted daytime temperatures down a bit more
starting Tuesday as it appears cold air arrives and then is slow
to leave until the end of next week. Still too early to talk about
any accumulating snow...but there certainly could be some...especially
across the north/northwest portion of the forecast area during the Monday night/Tuesday
time frame...as a potent vorticity lobe rotates through. The weather then looks
dry next Thursday/Friday. Highs Tuesday in the upper 30s northwest to the
low/middle 40s southeast. Highs Wednesday/Thursday mainly in the 30s to low 40s. Lows
through the period generally in the 20s to low 30s.
Aviation /10z Saturday through Wednesday/...
VFR conditions will persist into sun morng...as hi pressure builds across
the area and off the northern middle Atlantic CST. Expect increasing hi clouds
later today into sun morng...esply over extreme southeast Virginia and NE NC as low
pressure intensifies off the Florida/Georgia CST tonight into sun morng. Strong or
very strong NE or north winds then expected over southeast Virginia and NE NC from
late sun morng into Monday morng...as the low continues to intensify
as it tracks NE well off the southeast and middle Atlantic CST. This system will
also bring a chance for rain Sun afternoon into Sun night mainly at ecg/orf.
Outlook...an upper level system is expected to trigger rain and
snow showers late Monday through Tuesday across the area. Brief IFR conditions
will be possible in precipitation.
kept Small Craft Advisory for all coastal waters until 7 am this morng...as seas of 4 to
5 feet...will subside to 3 to 4 feet...as northerly winds become 5 to
10 knots. Otherwise...we should get a break in the action today and
the first half of tonight as hi pressure will be over the waters. Then...the
next system brings rough weather back to the marine area on sun.
Low pressure bombs off the NC CST by late sun...then quickly heads NE
and well out to sea on Monday. Latest model guidance still shows a
quick and significant increase in winds/seas across the southern waters by
late sun morng through sun evening...with deteriorating conditions
across the entire marine area by later sun into Sun night. Kept a gale
watch up for now across the southern coastal waters and Currituck sand...but
have also added the mouth of the Bay (starting 10 am sun for north-NE
winds gusting to 40-45 kt). Solid Small Craft Advisory conditions appear likely
across the remainder of the marine area as well...but will wait to
hoist next wave of sca's until current headlines expire and we get
another look at the models during today. Have seas increasing to
7-12 feet (highest s) for now...and that could be too conservative
given eventual strength and track of the low. Have waves reaching
5-6 feet at the mouth of the Bay late sun. Winds should diminish by
Monday morning...but seas will be slow to subside...and should
remain elevated at least into early Tuesday.
river flood warnings remain in effect for the Blackwater above
Franklin...Nottoway at Sebrell and Stony Creek...cashie at
Windsor. Have cancelled the warning at Richmond/Westham as water
levels have dropped below flood stage there. This all due to the
combo of recent snowmelt and the runoff from the recent heavy
rainfall. See flsakq for details.
Marine...gale watch from Sunday morning through Monday morning for
Small Craft Advisory until 7 am EST this morning for anz650-