Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/16/21
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
915 PM CST Fri Jan 15 2021
.UPDATE...
Issued at 915 PM CST Fri Jan 15 2021
Clouds will remain across much of the eastern cwa through the
night with winds slowly decreasing across all of the cwa.
Temperatures will fall into the teens by morning.
UPDATE Issued at 603 PM CST Fri Jan 15 2021
Updated for the expiration of the blizzard warning.
UPDATE Issued at 530 PM CST Fri Jan 15 2021
00z aviation discussion updated below.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 308 PM CST Fri Jan 15 2021
Sustained northerly winds of 20 to 30 mph, with gusts of 40-45 mph
will continue subsiding through this evening and overnight. Eastern
South Dakota is currently seeing some of the higher winds gusts,
with blowing snow noted on webcams. Patchy freezing drizzle has also
been observed. Buffer soundings indicate the loss of ice crystals
in the dendritic growth zone, more widespread freezing drizzle
will be possible. The past few runs of the RUC shows a deep moist
layer from 0-2 KM remaining over the far eastern CWA through at
least 9Z. May need to replace the blizzard warning in eastern SD
with a winter weather advisory for freezing drizzle and blowing
snow. The current blizzard headline expires at 0Z, which seems
reasonable at this time.
The rest of the short term, through Saturday night, appears dry for
this CWA. Northerly flow aloft, along with weak increasing heights,
limited to no CAA, temperatures should remain above normal for this
time of year.
.LONG TERM...(Sunday through Friday)
Issued at 308 PM CST Fri Jan 15 2021
Not much of a change in the overall pattern in the extended from
previous forecast iterations. Our region will be under the influence
of northwesterly flow aloft. Models remain in fairly decent
agreement on progging a clipper system to move through the region by
late Sunday through Monday. In-house blend continues to generate
roughly a tenth of an inch of QPF in portions of our north and
western forecast area. This would give those zones upwards of an
inch or so of snow. This coincides with other available guidance, so
no reason to deviate the forecast at this time.
The remainder of the period looks to become more quiet. Temperatures
will modify some as midweek approaches and an area of low pressure
tracks across southern Canada by Wednesday. We will look to stay
mostly dry as the upper pattern shifts from northwesterly flow to
split flow and precipitating systems get diverted away from our
area. A sfc frontal passage toward the end of the period will bring
cooler conditions back into the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 530 PM CST Fri Jan 15 2021
Terminals KABR,KATY,KPIR,KMBG
MVFR/IFR stratus will slowly decrease from west to east across south
dakota through the night and Saturday. ABR and ATY will the most
affected with ABR becoming VFR on Saturday. Otherwise, the winds
will also decrease from the northwest tonight and then increase
again on Saturday to 15 to 25 knots mainly at PIR and MBG.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Mohr
SHORT TERM...SD
LONG TERM...Vipond
AVIATION...Mohr
Area Forecast Discussion
National Weather Service Charleston SC
903 PM EST Fri Jan 15 2021
.SYNOPSIS...
A strong cold front will move across the area this evening,
followed by cool high pressure through the weekend. A low
pressure system could affect the region late next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The back edge of the rain will clear McClellanville shortly with
dry conditions prevailing thereafter. Although the cold front is
approaching the I-95 corridor, the core of the driest air is
trailing the front by several hours. As skies have cleared and
winds are dropping off in the wake of the front, areas of fog
have rapidly developed. Webcams from Claxton and Statesboro
along with county warning point reports across the Savannah
River into Allendale indicate the dense fog has become fairly
widespread. The most dense fog appears to be aligning well with
the lowest 1000 hPa RAP condensation pressure deficit progs from
its 17/00z run. The output expands the dense fog into
Walterboro soon and possibly as far east as Dorchester and lower
Charleston County. Given the current trends, a Dense Fog
Advisory has been issued from Bulloch and Screven Counties in
Georgia northeast to Inland Colleton in South Carolina through
midnight. Although patchy dense fog will linger in the Millen-
Reidsville-Ludowici region over the next 1-2 hours, the risk
for more significant dense fog will persist over the Dense Fog
Advisory area. The advisory could very well be cancelled for
some zones prior to midnight (best chances for this is in the
Georgia zones) as drier air advects in from the west. Similarly,
an expansion into Dorchester and Charleston Counties could be
needed.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
The mid-levels will consist of a trough moving over the East Coast
Saturday, followed by zonal flow Sunday, then another trough
swinging through the East Coast on Monday. At the surface, broad
high pressure centered over the Southern Plains Saturday will pass
to our south on Sunday, with a second, reinforcing high following
the same path and becoming located to our southwest on Monday. The
highs will bring strong subsidence, dry conditions, and mostly clear
skies to our area. Saturday will be the coldest day of the bunch due
to cold air advection. Additionally, 850 mb temperatures and
thickness values only support temperatures in the upper 40s to maybe
50 degrees at best. It`ll be breezy as well, especially in the
afternoon. Wind gusts could reach into the 30s, especially at the
beaches. Saturday night, winds are expected to ease. But good
radiational cooling will cause temperatures to bottom out in the 20s
inland and near freezing along the immediate coast. Temperatures
should warm 1-3 degrees on Sunday and then again on Monday at the
airmass moderates.
Lake Winds: Strong cold air advection will cause wind gusts to reach
25 kt across Lake Moultrie on Saturday. A Lake Wind Advisory is in
effect.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Surface high pressure will continue building into the region
with the center generally focused in the Southeast. A dry/rain-
free forecast is in place through Thursday. By Friday, weak low
pressure crossing the Appalachians along with upper-level
shortwave activity focused mainly in the Northeast will
propagate over the region, possibly bringing light scattered
showers Friday afternoon into early Saturday. A tight moisture
gradient will accompany this disturbance; therefore, showers
will likely fall where the greatest moisture content aligns
itself, which could be limited to just our northern counties
where weak forcing mechanisms are in place. A gradual warming
trend is anticipated through the period with highs in the mid to
upper 50s on Monday climbing well into the 60s late week.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A strong cold front continues to move through the terminals this
evening, with showers lingering a little longer than anticipated.
Have continued mention of rain as well as MVFR cigs at each terminal
until around 02/03Z when the showers should move all the way
offshore. VFR will prevail thereafter, but will have to watch
for a brief period fog/stratus to form between the end of the
steadier rains and FROPA, mainly at KCHS. Beginning around
daybreak, gusty west winds will arrive at each terminal,
bringing gusts upwards of 25-30 knots and continuing into the
afternoon hours.
Extended Aviation Outlook: VFR.
&&
.MARINE...
This Evening and Tonight: A strong cold front will approach the
local waters, likely passing offshore during the early overnight
period. Southerly winds around 10-15 kt should increase once fropa
occurs, turning west and increasing up to 15-20 kt with gusts to
25 kt across offshore Georgia waters and nearshore waters off the
Charleston County coast. Seas will also build, reaching 3-5 ft
overnight. Given the expected trend, Small Craft Advisories are
in effect for offshore Georgia waters and northern SC waters
this evening and through tonight. Winds could become marginally
supportive of advisories in remaining marine zones late tonight,
but should remain just below advisory levels before increasing
around daybreak.
Saturday: The combination of high pressure building into the region
and cold air advection will lead to an elevated surface pressure
gradient. Expect strong, gusty winds, especially in the afternoon.
Gusts could be near gale during this time period, mainly across the
easternmost portions of the Charleston waters and the GA waters
beyond 50 nm. But the areal and time coverage doesn`t appear to be
great enough to prompt Gale Warnings. Instead, Small Craft
Advisories are in effect for all of the ocean waters, now including
the Charleston Harbor. The gradient will level off in the evening
and overnight, causing winds and seas to lower. All Advisories
should expire by daybreak Sunday.
Sunday and beyond: High pressure will prevail. There is a potential
for Small Craft Advisories again Sunday night into Monday, mainly
due to wind gusts.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Dense Fog Advisory until midnight EST tonight for GAZ088-100-
101.
SC...Dense Fog Advisory until midnight EST tonight for SCZ040-042-
043-047.
Lake Wind Advisory from 11 AM to 6 PM EST Saturday for SCZ045.
MARINE...Small Craft Advisory from 7 AM Saturday to 4 AM EST Sunday for
AMZ352.
Small Craft Advisory until 4 AM EST Sunday for AMZ350-374.
Small Craft Advisory from 7 AM to 10 PM EST Saturday for
AMZ354.
Small Craft Advisory from 10 AM to 6 PM EST Saturday for
AMZ330.
&&
$$
Area Forecast Discussion
National Weather Service Grand Rapids MI
808 PM EST Fri Jan 15 2021
LATEST UPDATE...
Update/Marine
.SYNOPSIS...
Issued at 300 PM EST Fri Jan 15 2021
- Snow impacts through tonight
- Another round of snow for Saturday night into Sunday night
- Possible significant cool down end of next week into the
weekend
&&
.UPDATE...
Issued at 808 PM EST Fri Jan 15 2021
I plan on keeping our headlines as they are. The MDOT road map
at 7:50 pm shows continued slow downs north of MOP on M-127 and
Route 10 from Clare to Reed City. Looking at road cams and other
web cams and also looking at our radar, the snow continues to fall
over that area. The south edge of the snow continues to slowly
lift northward. The latest HRRR and RAP models show the snow being
out of our CWA by midnight and those models have been tracking the
snow nicely all day. It looks like another 1 to 2 inches may fall
there before it all ends later this evening. So, based on the
roads showing slow downs and that snow continues to fall it makes
sense to keep the Winter Weather Advisory through 11 pm.
Otherwise clearing ( actual clear skies) have moved northward into
our southern CWA (dry slot of the occluded system). Most of our
observation sites along I-94 now show clear skies. This likely
will lead to icy spots on area roads but also sidewalks and
parking lots so be careful if your walking around outside tonight.
I will update the HWO to say that shortly.
The back edge of the system will bring the snow showers back into
the area from west to east but this will be a slow process and it
will mostly impact areas west of US-131 Saturday afternoon into
the evening. Snowfall from this will be light and temperatures
will likely be just above freezing so I not see this an unusually
hazardous event.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 300 PM EST Fri Jan 15 2021
- Snow impacts through tonight
The mid level low centered over SW IL will continue to spread a band
of snow through the CWA this afternoon into the evening. Based on
satellite and radar trends...the northern zones will see the best
chance for accumulating snow. While temperatures will largely
remain above freezing through mid to late afternoon...the
temperature will drop off a few degrees after sunset. Thus the
impacts are expected to increase then. Based on many of the
models...several more inches of snow are possible where we have
the winter weather advisory out. Thus we will keep the headline
going and it may need to be extended if the snow and associated
impacts persist after midnight. The snow is expected to taper off
after evening as mid level heights start to rise and a ridge
approaches from the west.
- Another round of snow for Saturday night into Sunday night
An upper level jet streak strengthens as is dives down the west side
of the trough over the plains Saturday night into Sunday. This
develops mid level wave that tracks through IL and IN. Being on the
north side of this mid level wave we will need to monitor the
potential for period of snow especially Sunday into Sunday night.
Given the stronger height falls that occur...this system has the
potential to lead to impacts.
- Possible significant cool down end of next week into the
weekend
Arctic air is shown to build in the Canadian Prairies during this
time with 925 mb temps dropping down into the -20 to -30 deg C
range. This is considerably different than the current pattern that
they are in. The main upper jet shifts well south of the Great Lakes
region as a surface wave of low pressure tracks from Ontario to New
England Thursday into Friday. On the backside of this departing
wave...stronger cold air advection is shown to draw some of the
arctic air into MI from the north for Friday. Then...the arctic
air is shown to continue to build upstream Saturday with another
front headed our way.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 642 PM EST Fri Jan 15 2021
I am expecting mostly VFR conditions over the CWA tonight as the
system slowly moves through the area. The band of snow is lifting
north of MKG as I write this. That is followed by an area of
clearing that may last 2-3 hours before VFR cigs move back in by
06z.
MVFR conditions will return on Saturday as the system slowly moves
out of the area. Western sections will see some mixed rain and
snow showers in the afternoon from this.
&&
.MARINE...
Issued at 808 PM EST Fri Jan 15 2021
I have issued a Small Craft Advisory for our entire near shore
from 2 pm Saturday until 2 pm on Sunday due north to northwest
winds of 15 to 25 knots and waves to 7 feet. Typically at this
time of year there would be ice in the near shore but not this
year.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory until 11 PM EST this evening for
MIZ038>040-044>046.
LM...Small Craft Advisory from 1 PM Saturday to 1 PM EST Sunday for
LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
930 PM EST Fri Jan 15 2021
.SYNOPSIS...
An anomalously strong mid and upper level low will wobble across the
OH Valley and middle Atlantic through Saturday.
&&
.NEAR TERM /TONIGHT/...
As of 930 PM Friday...
Regional radar data indicate the lead band of rain and deep moisture
has progressed into the NC Coastal Plain this evening; and this band
will continue ewd and out of the RAH CWA during the next couple of
hours. Clearing behind that band of rain, atop continued moist and
calm to light and variable flow at the surface, will result in the
ewd expansion/development of fog tonight from the wrn and srn
Piedmont, including some dense. Light swly flow and incoming drier
air now over the Upstate of SC will then begin to overspread the srn
NC Piedmont very late tonight; and that developing regime will tend
to erode the preceding blanket of low overcast and fog from the
southwest through Sat morning.
In addition to the threat of dense fog, a small area of
precipitation developed across Burke, Alexander, and Caldwell Co. in
the past couple of hours and has since moved newd across Yadkin and
far wrn Forsyth Co. This precipitation appears to be related to an
area of concentrated ascent and moistening ahead of an embedded vort
max/perturbation evident over Davie Co. in 02Z/16th WV imagery, and
also in an elongated region of upr divergence within the entrance
region of a 150-160 kt 250-300 mb jet observed from BMX/FFC newd to
GSO/RNK in 00Z upr air data. A chance of rain will consequently
result for the next few hours over the nrn Piedmont, before the
foregoing perturbation lifts newd into VA. And lastly, WFO GSP shared
reports within that precipitation area of a mix of rain and frozen
precipitation - likely partially melted snow/graupel given the
presence of very weak elevated instability within an already cold
(mixed phase) cloud, with partial melting of that frozen
precipitation as it falls into a ~750 m above freezing boundary
layer per the 00Z GSO sounding and RAP point forecast soundings
around the Triad. As such, the rain may mix at times with partially
melted snow/graupel, with no accumulation given surface temperatures
in the mid 30s to near 40F.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 315 PM Friday...
The broad upper level low responsible for surface low pressure and
today`s cold front will remain to the north along the Great Lakes,
but a trough associated with the low will rotate over central North
Carolina Saturday afternoon. While moisture will be shallow, lapse
rates towards the surface will be high resulting in a good amount of
low level instability and gusty winds between 20-30 mph. There
should be enough moisture and lift from the trough axis to allow for
isolated showers to develop. While high temperatures will be in the
40s, the above-freezing layer at the surface will be very thin,
considering the high surface lapse rates mentioned earlier. As a
result, cannot rule out that showers could be a mix of rain and
snow, although with air temperatures in the 40s, no accumulation
would be expected.
Skies will clear out quickly after sunset with the loss of
instability, although winds will remain out of the west-southwest
around 5 mph overnight. Overnight lows will be in the upper 20s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 200 PM Friday...
Through Wednesday: A secondary upper low will swing through the
Great Lakes on Sunday and Monday in the wake of the larger scale
low. This low is fairly moisture starved, so have taken chance of
rain out of the forecast for Monday. Generally expect high
temperatures in the mid 40s NW to around 50 degrees SE Sunday and
Monday. Lows Sunday night will generally be in the upper 20s to low
30s, decreasing for Monday night with lows bottoming out in the mid
20s. Upper level flow will become zonal Tuesday and Wednesday as the
sub-tropical ridge begins to strengthen over the Gulf. At the
surface, high pressure will sit over the Southeast/FL through
Wednesday, with a series of dry, reinforcing cold fronts passing
through the mid-Atlantic through mid-week. As the moisture advection
into the lower MS Valley increases Wednesday night, there is slight
chance some of that moisture could make it into central NC along the
frontal zone. Should that occur then there would be a chance for
some precipitation, possibly non-liquid, to occur. For now, will
keep the weather dry through Wednesday night with increasing chances
thereafter. Temperatures will be fairly consistent through the
period, with highs generally in the upper 40s to mid 50s and lows in
the 30s.
Thursday and Friday: A potent low will dive south through the
Rockies into the Desert Southwest Tuesday/Wednesday. A broad
northern stream low will migrate south into the western Great Lakes
Wednesday night/Thursday and continue swinging eastward through the
Northeast through Friday as the southern stream low weakens over the
Southwest, subsequently lifting east-northeast into the Plains/MS
Valley. The weather specifics for central NC for the end of the week
is still somewhat uncertain as some significant differences exist
between the medium-range models, largely with respect to the when,
where and how much precipitation will fall. However, there is a
consistent signal for good moisture advection into the lower MS
Valley ahead of the low/trough, so there is the potential for a
decent amount of rainfall. Highs will generally range from the low
to upper 50s. Lows should be somewhat mild in the 40s Thursday
night, likely decreasing for Friday night.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 710 PM Friday...
A band of rain and deep moisture/multi-layered cloudiness will
continue to move east and affect FAY and RWI for another couple of
hours this evening. Clearing behind that band of rain, atop
continued moist and increasingly calm conditions near the surface,
will result in the continued development and gradual ewd expansion
of LIFR visibility restrictions and LIFR-IFR ceilings that have
already enveloped INT/GSO as of 00Z. Light swly flow and incoming
drier air now over wrn SC will begin to overspread the area from CLT
to FAY very late tonight; and that developing regime will tend to
erode the preceding blanket of low overcast and fog from the
southwest through Sat morning. While conditions are expected to
become VFR area-wide by 13-14Z Sat, VFR ceilings and widely
scattered showers will develop with diurnal heating, beneath cold
temperatures aloft accompanying a passing mid/upr-level low, between
17-22Z Sat, then dissipate with loss of heating. Additionally, wswly
winds may briefly become strong and gust into the 20s kts as the
associated mixed/boundary layer deepens during the afternoon.
Outlook: VFR conditions are forecast through the middle of next
week.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...Green
LONG TERM...KC
AVIATION...MWS
Area Forecast Discussion
National Weather Service Blacksburg VA
952 PM EST Fri Jan 15 2021
.SYNOPSIS...
A cold front will head east of the region overnight. Another system
capable of producing some snow across the mountains will move into
and across the region on Saturday, and be followed close behind by
yet another on Monday. Temperatures start to moderate next week, but
will be accompanied by weather systems again potentially on Tuesday
and Thursday.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 953 PM EST Friday...
Winter Weather Advisories remain in effect for 7 AM Saturday
until 7 AM Sunday for portions of southwest Virginia, northwest
North Carolina and southeast West Virginia.
Fog Advisories remain in effect until 4 am Saturday for Virginia,
Carroll, Floyd, Patrick and Henry Counties in Virginia. In
North Carolina, Surry, Stokes, Rockingham, Wilkes and Yadkin
Counties.
HRRR and NARRE along with surface observations support areas of
dense fog tonight. Expected winds to increased Saturday morning
especially along the southern Blue Ridge as highlighted by
NAMnest. This will break up or lift pockets of fog Saturday
morning. Adjusted temperatures for tonight into Saturday
utilizing the latest surface obs, their trends and blended in
NBM and coop mos. Lowered low temperatures down in the west to
capture the colder readings. Modified pops and weather to
include the area of precipitation associated with shortwave
rolling east across the southern portions of the forecast area.
Used a mixture of HRRR,hires arw and namnest to place the
pocket of precipitation. More changes later tonight.
As of 655 PM EST Friday...
Have introduced more widespread dense fog as well as an advisory
as several locations are reporting a quarter mile or less
visibility already this evening. Plenty of moisture around and a
strengthening inversion should keep conditions favorable for
dense fog in the advisory area. A wind shift should arrive 2-4
AM and gradually erode the low level moisture.
Areas outside of the dense fog advisory area will see more
patchy and transient fog, some of which may be dense. Roadways
will become treacherous overnight as temperatures continue to
drop into the lower 30s to mid/upper 20s under mostly clear
skies. Additional cloud cover/showers will develop in upslope
flow by morning west of the Blue Ridge and shift east during the
day.
As of 230 PM EST Friday...
A Winter Weather Advisory will be issued for Saturday, continuing
through Saturday night for parts of the area.
A cold front has been progressing across the area this afternoon. A
mix of rain, sleet, and snow has been associated with it. Once it
has moved passed a particular region, cold air advection is eroding
the low level warm nose, thus allowing for either a p-type of either
rain or snow, depending upon the local surface temperature. However,
by the time this is happening, we are very near the back edge of the
precipitation associated with the front. So when pure snow in the
west has been starting, it is not lasting too long until the
precipitation ends as a whole.
By early this evening, only a few hours of precipitation either
either mainly rain showers or snow showers will exist across the far
northern and eastern parts of the area before it ends. Most of the
late evening, and even into the start of the AM hours of Saturday,
limited if any precipitation is expected across the region.
We will be watching an upper low progress southeast towards the area
from the western Great Lakes region. Moisture and lift associated
with this feature will bring a return of snow showers to far western
portions of the area around daybreak Saturday. During the day,
coverage across the mountains will increase, and allow for
measurable snowfall, especially at the higher elevations of
southeast West Virginia, south into the Northern Mountains of North
Carolina. Snows will continue into Saturday night. With the snow
expected in this area on Saturday into Saturday night, will be
hoisting a Winter Weather Advisory within this region.
Winds will also be on the increase on Saturday. Gusts close to
30 to 40 mph will be possible at some of the higher elevations.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 200 PM EST Friday...
Confidence is high for brisk/cold weather and scattered
snow showers/flurries through the Short Term.
A closed low over the Northeast is expected to depart Saturday
night. Close on its heals will be another shortwave disturbance
which is progged to cross the Ohio Valley Sunday, then across the
Mid-Atlantic region Sunday night and Monday. This will result in
prolonged west to northwest wind flow and moisture into the
mountains with an opportunity for snow showers and flurries.
Greatest snow accumulations will be across the higher elevations
with lesser amounts farther east per downslope drying east of the
Blue Ridge. It will remain brisk and cold with temperatures 4 to 8
degrees below normal, but nothing extreme. Wind gusts of 20 to 30
mph will keep wind chill values in the teens, and single digits for
the highest elevations. Actual air temperatures are expected to
range from around 30 in the mountains to the lower 40s in the
piedmont.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 200 PM EST Friday...
Temperatures are forecast to trend closer to normal for mid-week.
A slight moderation of temperature is expected for mid-week as the
flow aloft becomes zonal in the eastern CONUS. There is a notable
split in the West where a trough detaches from the upper flow over
the southwestern CONUS. This configurations suggests the northern
stream will remain progressive, supporting fast moving short waves
across the northern tier, whereas the southern stream will be more
amplified and yielding to the organization of a low pressure system
over the Southern Plains.
Evolution of the southern stream system for the end of the week is
still in question. As long as the northern stream remains confluent
and zonal, the tendency will be to keep the developing storm over
Texas confined to a latitude. Even if it were to trend farther north
with time, the temperature profile would favor more rain than snow.
85H temps of +6 to +10 deg C are being forecast from the Southern
Plains across the Deep South for Thursday and Friday...the colder
air retreating to the Great Lakes and New England.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 655 PM EST Friday...
HRRR and NARRE as well as observations are showing some dense
fog develop across the area as the sky clears in the wake of a
cold front. Expecting northern NC as well as south central and
even southeastern VA to be impacting until a wind shift arrives
around 07-09Z. In the meantime LIFR conditions can be expected
at times, especially at KLYH and KBCB.
As of 1230 PM EST Friday...
A cold front is making its way across the area. A mix of snow,
sleet and rain is accompanying this feature, along with a mix of
IFR/MVFR ceilings and VFR/MVFR visibilities. Localized LIFR
cigs and IFR vsbys also exist. The front and its features will
exit the region this evening, bringing a brief return to
improved flight conditions for parts of the area by late this
evening.
By the time conditions start to improve, they will start to
trend downward again as we approach Saturday morning, especially
in the west as our next system draws closer to the area. This
system will bring scattered snow showers to the mountains
Saturday morning.
Winds will come around to the west for most locations by the end
of today, and increase in speed during the day Saturday.
Confidence in the above aviation scenario is moderate to high.
Extended Aviation Discussion...
Saturday into Sunday, disturbances crossing the area bring snow
showers to primarily western parts of the region. Sub-VFR
conditions are expected with this activity across mainly the
mountains.
A break Sunday before a more robust system crosses the area on
Monday, bringing the chance of sub-VFR conditions to not only
the mountains, but potentially some area east of the crest of
the Blue Ridge.
By Tuesday, high pressure will start to build into the area.
Other than some early morning river/valley patchy fog, VFR
conditions are expected.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Winter Weather Advisory from 7 AM Saturday to 7 AM EST Sunday
for VAZ007-009-015.
Dense Fog Advisory until 4 AM EST Saturday for VAZ016-017-032-
043.
NC...Winter Weather Advisory from 7 AM Saturday to 7 AM EST Sunday
for NCZ001-018.
Dense Fog Advisory until 4 AM EST Saturday for NCZ003>005-019-
020.
WV...Winter Weather Advisory from 7 AM Saturday to 7 AM EST Sunday
for WVZ042-043-508.
&&
$$
SYNOPSIS...DS
NEAR TERM...KK/SH
SHORT TERM...PM
LONG TERM...PM
AVIATION...DS/SH