Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KAKQ 231712
Area Forecast Discussion
National Weather Service Wakefield VA
112 PM EDT SAT JUL 23 2016
High pressure prevails over the region through Monday. A weak front
drops south across the northern Delmarva tonight, then lifts back to
the north Sunday. A weak cold front drops into the region Tuesday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The current surface analysis depicts high pressure centered from
the mid-South to the wrn Atlantic with a lee-side trough east of
the mountains. Aloft, a ridge is centered over the Mississippi
Valley region with a trough over Atlantic Canada. The airmass
appears too capped today for convection despite the presence of
a lee-side trough. Thus, a dry forecast has been maintained
through 21z before a slight chc PoP reaches the lower MD Ern
Shore. 850mb temperatures remain in the 20-22C range (+2 st dev).
This should support highs solidly in the mid 90s to locally upper
90s inland today, with highs reaching the low 90s at the coast.
Some mixing is expected this afternoon resulting in dewpoints
averaging in the 70-73 range during peak heating hours. This
results in heat indices between 100-104 (although some of the
AWOS sites will report a bit higher than that). Highest heat
indices will be across SE VA and NE NC. Premise here is that
guidance has been around 2 degrees to warm past few days.
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
High res data in decent agreement that a shortwave trof results in
sct convection developing this evening. Data has this activity
mainly across the northern neck / lwr Md eastern shore before
weakening as it drifts SE after midnite. Will carry 30-40 pops there
with a 1-2 county buffer zone of slght chc pops mainly NE of I64.
Otherwise...a warm and muggy night with lows in the mid-upr 70s.
Frontal boundary weakens as it lifts north of the fa Sun. High prs
dominates along with the thermal trof across srn VA / nrn NC. Kept
slght chc pops btwn 18Z-00Z ivof this feature. 850 mb temps support
highs in the mid-upr 90s. Dp temps progged about 1-2 degrees higher
than today which results in heat index values aoa 105 (heat advsry
levels) for most of the southern half of the fa.
Fair and muggy Sun nite with any convection quickly dissipating
after sunset. Lows in the mid to upper 70s.
Monday appears to be the hottest day of this stretch with only a low
chc pop across the nwrn zones late for any convection that develops
across the mts and drifts east. Highs 95-100 combined with dp temps
btwn 70-75 yields heat index values btwn 104-108 (heat advsry levels).
Will continue to address the heat in the HWO.
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A cold front crosses the region on Tuesday and then stalls over
the area during the rest of the week...fluctuating/wobbling its
position over time in persistent zonal flow aloft. Temperatures
still expected to peak in the low-mid 90s for highs with dewpoints
in the low-mid 70s. This will generally maintain heat index values
of 100-104 degrees each afternoon. Lows generally in the mid 70s
each night. Precip chances finally increase to a decent 30-40% POP
each afternoon...beginning with the frontal passage on Tuesday
afternoon/evening. Thunderstorms should be expected each day. Main
impacts will be strong wind gusts and locally heavy rainfall due
to pwats upwards of 2.00 inches.
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --VFR conditions and light winds prevail this afternoon at all
terminals. This will continue through the 18Z TAF period and
probably beyond. Winds will generally be 10 kts or less, and out
of the S/SW, although onshore flow should persists through the
afternoon at KORF. Still the potential for a shwr/tstm later this
evening/tonight at KSBY, as a weakening front drops into the
area. However, enough uncertainty persists, and latest hi-res
models have backed off on the potential, to include in the TAF.
A cold front drops into the area Tuesday/Wednesday bringing
isolated- scattered shwrs/tstms both days...primarily during the
afternoon/evening hours. Brief reductions in VSBYS and CIGS to
MVFR/IFR levels are possible with the storms.
-- End Changed Discussion --
All headlines have been cancelled as sca conditions have not
materialized this morng. Expect a fairly stagnant wx pattern over
the next few days with hi pressure centered off the se coast and
weak trofs of lo pressure over the Mid Atlc. Winds will avg 10-15 kt
out of the s/sw thru this period with 1-2 ft waves over the Bay and
mainly 2-3 ft seas over Cstl Wtrs. The next cold front drops into
the area late Tue/Tue night. Sub-sca conditions expected to
continue thru at least mid week.
While its certainly going to be hot today thru Mon, climatologically
this is the hottest time of the year with several heat waves having
occurred in the past that have been far more intense than what we
will experience. Record highs are unlikely to be set and in most
cases, doubt they will even challenged within 5 degrees.
* RECORD HIGHS:
* Sat (7/23) Sun (7/24) Mon (7/25)
* RIC: 103 (1952) 105 (2010) 105 (2010)
* ORF: 103 (2011) 105 (2010) 105 (2010)
* SBY: 103 (2011) 101 (2010) 100 (2010)
* ECG: 104 (1952) 97 (2012) 99 (1949)