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000
FXUS61 KAKQ 031426
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
1026 AM EDT Mon Aug 3 2020

.SYNOPSIS...
High pressure off the coast will remain in control over the
local area into this afternoon. Please see the latest
advisories from the National Hurricane Center concerning
Tropical cyclone Isaias which is forecast to impact the region
later tonight into Tuesday afternoon.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 230 AM EDT Monday...

A band of showers/tstms is pushing nwd into NE NC late this
morning. Warm and humid this morning with temperatures in the
upper 70s to mid 80s. Otw...sfc hi pres off the coast continues
to nose itself W into the FA...and will do so through this
morning. Eventually this afternoon/early this evening...tropical
moisture will begin to increase from the S...leading to the
development of areas of SHRAs/tstms. Starting out at least
partly sunny for all except far N-W then VRB clouds-mostly
cloudy this afternoon. Highest PoPs (60-70%) will generally be W
of I 95...tapering to 30-40% E. Locally heavy rainfall and
brief gusty winds are poss w/ any SHRAs/tstms later today. Highs
in the m-u80s (could RIC break the 90F max streak?).

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
As of 245 AM EDT Monday...

No big changes wrt forecast and impacts from TC Isaias late
tonight/Tue. Forecast guidance continues to an inland track
(landfall near the coast at the NC-SC border tonight). The storm
will be moving rather briskly NNE thereafter...which brings it
into the local area very late tonight into Tue afternoon (although
there are still some timing differences amongst numerical guidance).
Please refer to the official NHC forecast for exact details
with respect to Isaias.

Impacts from Isaias are expected to arrive late tonight and continue
into Tue afternoon. High potential exists for (widespread) heavy
rain and breezy to windy conditions (for about a 6-8hr time
frame at any particular location)...as well as the potential for
isolated tornadoes (ern VA/the ern shore and NE NC). Have made
only minor adjustments to the axis of heaviest rainfall and
forecast QPF as the storm interacts w/ a trough aloft to the
WNW and as a strong upper jet (100+kt at 200 mb) develops N of
the tropical low. As this occurs the forward speed of the storm
will increase. The latest QPF forecast is still for generally
4-6" along and W of the I-95 corridor...3-5" over the interior
coastal plain...and tapering to 1-2" toward the coast. A Flash
Flood Watch remains in place for late this evening/tonight
through Tue afternoon for most of the area...excluding coastal
NE NC, SE VA and the Atlantic coast of the Ern Shore. Strong
low-level shear and SRH are expected E of the track bringing a
tornado potential initially to NE NC/SE VA late
tonight...spreading nwd Tue. The tornado potential and the
extent will be dependent on how much destabilization is able to
occur E of the track along with the location of any surface
boundaries.

Lows tonight in the u60s-l70s inland to the l-m70s at the coast.
Highs Tue in the u70s-l80s inland to the l-m80s at the coast.

Conditions settle down Tues night into Wed as Isaias moves to the
NE. There is a chc of diurnal showers/tstms Wed afternoon. Seasonal
temperatures with lows in the upper 60s/low 70s Tue night...followed
by highs in the upper 80s/low 90s Wed.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 530 PM EDT Sunday...

As Tropical Storm Isaias pulls away from the area, a broad
upper trough will remain in place across the Great Lakes and
Ohio River Valley through Saturday. A sfc trough will be
located east of the Appalachian Mountains through the early
part of the weekend. This will allow for widespread
thunderstorms to develop across the area each afternoon and last
until shortly after sunset. Temperatures will not be as hot as
previous weeks with the increased tstm chances and associated
cloud cover. Highs 87-92F and overnight low temperatures in the
upper 60s to mid 70s. Even though dew points will be in the low
70s, heat indices are expected to remain below 100 degrees.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
As of 635 AM EDT Monday...

SCT-BKN SC (largely MVFR) for a part of the morning then SCT-BKN
CU w/ increases CHCs for SHRAs/tstms this afternoon/evening (which
would be accompanied by brief flight restrictions in heavy rain/lower
CIGs). Kept VCSH for now given uncertain coverage attm. SSW winds
5-15 kt. More widespread (potentially heavy) rain...reduced
VSBY/CIGS...along with breezy to windy conditions are likely
late tonight into Tue afternoon as lo pres (tropical cyclone
Isaias) crosses the area from south to north. Conditions transition
back to more diurnal showers/tstms Wednesday through Friday.

&&

.MARINE...
As of 600 AM EDT Monday...

Early morning surface analysis shows low pressure centered in
southern Quebec with a surface trough extending southward into the
Mid-Atlantic states. Tropical Storm Isaias is centered roughly 150
miles SE of Jacksonville, FL moving NNW parallel to the FL coast.
Locally, winds across the marine area are SW 15-20 knots from Cape
Henry northward and 10-15 knots to the south. A few gusts to 25
knots have been noted overnight, especially at elevated sensors on
the east and northeastern Ches Bay. Waves in the bay are 1-3 ft with
seas averaging 3-4 ft. Winds will decrease to 10-15 knots and
become SSE today as the trough lifts away to the NE.

Attention then turns to Isaias. 00z/03 guidance has come into better
agreement with respect to the track/intensity of Isaias, but there
are still some differences with respect to timing. GFS remains
the fastest of the bunch, about 6 hours ahead of the GEM/ECMWF.
There have only been minor shifts in the forecast track since
last night but global models do show a modest increase in
strength over the next 12-24 hours vs the previous forecast,
resulting in a slightly stronger wind field for our area. The
latest NHC track is faster and shows Isaias making landfall
just S of the NC/SC border Monday night before moving to just
east of Raleigh. Isaias will likely track NNE near/just to the
west of the Chesapeake Bay on Tuesday morning before quickly
exiting to the N/NE Tue afternoon. Isaias is expected to
maintain tropical storm strength as it tracks through the area,
so TS Watches have been upgraded to TS Warnings for the ocean,
bay, Currituck Sound, and all of the rivers. Looks like the most
likely timing for tropical storm conditions will be from around
2 AM through 2 PM Tuesday. The earliest onset of TS conditions
will be across srn marine zones, with the latest onset of TS
conditions occurring across nrn marine zones. There is the
potential for sustained winds of 40-50 kt with gusts up to 60-65
kt during this timeframe. The strongest winds will generally be
from the S or SE across the marine area (E of the center of
Isaias). Given that Isaias will be gaining forward speed as it
tracks through the area, tropical storm conditions will last no
more than 6-8 hours or so at any given location. Will continue
to advertise increasing winds /waves-seas late Mon night-Tue AM
before winds, waves, and seas quickly decrease Tue evening in
the wake of Isaias. Sub- SCA conditions return on Wed and are
expected to last through Fri. Please see the latest advisories
from the National Hurricane Center concerning the track of
Hurricane Isaias.

&&

.TIDES/COASTAL FLOODING...
As of 530 AM EDT Monday...

Tidal flooding is possible across parts of the area on Tuesday-early
Wednesday morning as TS Isaias tracks NNE through the area. Strong S
to SE winds for a 6-8 hour period will result in rapidly rising
water levels across the mid/upper Ches Bay (especially the bayside
of the Lower MD Ern Shore) and also in areas on the north side of
the Albemarle/Currituck Sounds. In coordination with neighboring
offices, Coastal Flood Watches remain in effect for the bayside
of the Lower MD Ern Shore, VA Northern Neck, all counties in NE
NC north of the Albemarle Sound, and VA Beach (for sound side
flooding). There is the potential for water levels to exceed
moderate flood thresholds in the watch area on Tuesday. The
latest guidance shows lower potential for water to be trapped in
the northern Ches Bay, but the forecast will continue to show
minor to low-end moderate flooding on the bayside of the Lower
Ern Shore early Wed AM. Thus, the Coastal Flood Watch for the
Lower Ern shore runs through ~06z Wed. Watches for NE NC/VA
Beach run through Tuesday evening.

While a watch has been issued for Northumberland/Westmoreland,
confidence remains quite low that Lewisetta will reach moderate
flood thresholds.

&&

.CLIMATE...
As of 230 AM EDT Monday...

RIC official had a high temperature of 96F Sun which made it 24
consecutive days of 90+F temperatures (the 2nd longest streak
in the period of record). The longest streak on record is 27
days in 1995.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Flash Flood Watch from 10 PM EDT this evening through Tuesday
     evening for MDZ021>023.
     Tropical Storm Warning for MDZ021>025.
     Coastal Flood Watch from late tonight through late Tuesday
     night for MDZ021>023.
NC...Flash Flood Watch from 10 PM EDT this evening through Tuesday
     evening for NCZ012>014-030.
     Tropical Storm Warning for NCZ012>017-030>032-102.
     Coastal Flood Watch from late tonight through Tuesday evening
     for NCZ015>017-030>032-102.
VA...Flash Flood Watch from 10 PM EDT this evening through Tuesday
     evening for VAZ048-060>062-064>069-075>090-092-093-096-
     509>524.
     Tropical Storm Warning for VAZ064-075>090-092-093-095>100-
     511>525.
     Coastal Flood Watch from late tonight through late Tuesday
     night for VAZ099.
     Coastal Flood Watch from late tonight through Tuesday evening
     for VAZ098.
     Coastal Flood Watch from late tonight through Tuesday evening
     for VAZ075-077.
MARINE...Tropical Storm Warning for ANZ630>638-650-652-654-656-658.
&&

$$
SYNOPSIS...AJZ/ALB
NEAR TERM...AJZ/ALB
SHORT TERM...AJZ/ALB
LONG TERM...CP/JDM
AVIATION...ALB
MARINE...ERI/RHR
TIDES/COASTAL FLOODING...AKQ
CLIMATE...AKQ