Area Forecast Discussion
Issued by NWS Wakefield, VA
FXUS61 KAKQ 010309
Area Forecast Discussion
National Weather Service Wakefield VA
1109 PM EDT WED AUG 31 2016
A cold front will cross the area on Thursday, then stall across
North Carolina Thursday night. Tropical Storm Hermine will lift
northeast across the southeastern states Friday and Friday night,
then continue northeast across the Mid Atlantic states Saturday
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Line of showers and thunderstorms tracking across the northern
portion of the local area, resulting in locally heavy rainfall.
These showers are in response to a surface trough over the
Piedmont, along with weak shortwave energy. These showers will
continue to push eastward toward the Northern Neck and Maryland
Eastern Shore. Additional isolated to widely scattered showers are
possible over the Piedmont into central Virginia tonight as a cold
front approaches from the northwest. Height falls and increasing
winds aloft will help push the showers toward the Eastern Shore,
but guidance indicates dry conditions central Virginia to the
southeast forecast area. Sky averages mostly cloudy north and
northeast to mostly clear southeast. Mild...with lows generally in
the low 70`s.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Cold front moves north to south across the region Thursday. No
severe weather expected, but data does indicated some moderate to
heavy downpours are possible across southern zones given some
daytime heating and rather high PW`s. Kept high chc pops for now.
Front settles across North Carolina Thurs night then stalls. Enough
residual moisture noted to keep chc pops going through the evening
across the north and through the overnight hours across the south. A
wind shift to the north will allow temps to drop into the mid to
upr 60s most areas except remaining near 70 along the sern coast.
Transition day Friday with the boundary stalled across the Carolinas
and high prs building into the area. Kept more clouds and low chc
pops across North Carolina. Dry with more sunshine across the north.
Cooler with highs around 80.
Forecast becomes rather challenging for the holiday weekend as a
major change seen in the 12z models with TS Hermine currently
across the GOM. NAM/GFS/SREF and even the 12Z ECMWF now track the
low inland with copious amounts of tropical moisture with it.
Given the more inland track, expect the tropical moisture to
overrun the stalled frontal boundary across the Carolinas Friday
night then push north into VA Saturday. Won`t get to fancy with
the grids given the uncertainty, but will trend toward a wetter
solution Friday night and Saturday. Given todays model runs and
track (along the I95 corridor), the potential exists for several
inches of rain across the fa along with the threat of severe
weather Saturday afternoon given the progged dry slot and low
level wind fields. Lows Friday night 65-70. Highs Saturday highly
variable and will depend on the track of the low. Highs 75-80.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Latest medium range guidance continues a slower and more westward
track of now Tropical Storm Hermine. The 18Z ensemble cluster now
favors a more inland track as opposed to a Gulf stream track, with
the system reaching the local area Saturday afternoon and evening.
Given the location of the digging trough over the western CONUS,
this scenario seems plausibly. Will await this afternoon`s NHC
prediction before getting into the specifics of the track. However,
confidence is increasing that the area will see showers over the
area to begin the extended period (Saturday night). Have opted to
increase POP`s across the region to solid chance Saturday night, and
start a generally clearing trend southwest to northeast through
Sunday night. Forecast is still on the conservative side based on
the uncertainty in the track once is reaches the Mid-Atlantic
Region. Gusty north to northeast winds expected along the coast
Saturday night and Sunday. The western CONUS trough deepens into
early next week as strong upper level high pressure builds over the
Deep South. An anomalous upper ridge also exists over over the
western Atlantic, resulting in very little steering flow for the
tropical cyclone. Medium range guidance is struggling with the
system thereafter, but expect deep, tropical moisture to push
offshore Monday and Monday night resulting in improving conditions.
Upper/surface high pressure results in dry conditions and warming
temperatures Tuesday and Wednesday.
Temperatures will be cool due to clouds and precip Sunday, with
highs in the upper 70`s to low 80`s. Thereafter, a warming trend is
forecast, with daytime temperatures warming back to near 90 by
Tuesday. Low 90`s forecast Wednesday.
As always, more specific information on Hermine is available via
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
VFR conditions over the region with sct to bkn low and mid level
clouds over early tonight. Winds continue to be E-SE and mostly
less than 10 kt. This could lead to some sct/bkn stratus in the
morning but not a strong indication from guidance. Right now will
show some VFR low/mid level clouds through the overnight. Some
patchy fog might develop but not expecting anything significant at
this time. A weak cold front moves into the area on Thursday and
this should result in some bkn VFR conditions through the day.
OUTLOOK...With the cold front present over the area...scattered
thunderstorms are possible Thursday afternoon and early evening.
There is a potential impact from tropical storm Hermine or its
remnants late Friday into Saturday. See updates from NHC. Mainly
dry weather expected for Sunday and Monday...at this time.
Tropical Depression Eight will continue to push out to sea
tonight. Se-s winds rather benign (aob 10kt) the rest of tonight
into Thu morning...becoming more w-nw ahead of an approaching cold
front during the aftn. A quick surge in winds to 10-15kt should be
anticipated...followed by a more nly surge behind the front late
Thu night into Fri morning. Speeds increase to a solid 15kt
Bay/Sound/coastal waters, therefore no sca flags at this time.
Winds veer to the ne for Fri and will average 10-15kt. Seas 2-3ft.
Waves 1-2ft...building briefly to 2-3ft during the nly surge late
Thu night into Fri.
Focus then turns to Tropical Storm Hermine, which is trending twd
a more inland track. TS Hermine`s winds are expected to start
impacting the waters Friday as speeds increase to 15-20kt in the
evening...then conditions deteriorate rapidly after midnight
Friday night and persisting through Sunday before conditions
improve. Winds generally ne-n during this timeframe. For the
coastal waters, speeds average 20-30kt with gusts of 35-40kt. For
Bay/Ern VA Rivers, speeds average 15-25kt with gusts to around
30kt. For Currituck Sound, speeds average 20-25kt with gusts to
around 30kt (35-40kt closer to Albemarle Sound) late Fri night
into Sat evening...then average 15-20kt late Sat night into Sun.
Seas around 3-4ft late Fri aftn...quickly build to 4-5ft north and
5-7ft south after midnight Fri night. Seas continue to build
through Sat as TS Hermine passes directly over the Mid Atlantic
Region. Seas should peak at 9-13ft out to 20NM by Sat evening and
then very slowly start to subside on Sun.
Long period swell and onshore waves deviating slightly from a
shore-normal direction (especially during afternoon low tide) will
maintain a moderate rip risk for all beaches for
Thursday...regardless of winds and seas diminishing for the day.
Given the latest track of TS Hermine, a threat for increased rip
risk will continue for all beaches throughout the holiday weekend.
Will maintain mention in the HWO. Also, the risk for areas of
minor coastal flooding/erosion (mainly lower Bay and along the
Atlantic Coastal zones) has increased for later Saturday and
Sunday. Will continue to monitor as forecast track information
evolves over the next 24-36 hours.
Has been a rather hot and dry month of August over much of the
area (quite a contrast to a summer that began very wet).
Current Data Through 8/30:
* Average Temperature
* RIC: 80.3/ would rank as 6th warmest (warmest is 82.9 in 1900)
* ORF: 81.4/ would rank as 2nd warmest (warmest is 81.9 in 1900)
* SBY: 78.7/ would rank as 5th warmest (warmest is 80.3 in 1978)
Based on forecast temperatures for today these rankings will
likely stay as is. Richmond has only received 0.53" of rain for
the month (if this stands (and it probably will) it will rank as
the 3rd driest on record).