Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/22/18
Area Forecast Discussion
National Weather Service Bismarck ND
937 PM CDT Sat Apr 21 2018
.UPDATE...
Issued at 929 PM CDT Sat Apr 21 2018
Current very strong post frontal westerly winds across
northeastern and north central Montana as of 02 UTC are not
expected at this time across northwest North Dakota later this
evening as the boundary layer stabilizes, and isallobaric forcing
decreases. However, will continue to monitor trends. Otherwise,
the forecast for tonight is on track and blended to observations
through 02 UTC.
UPDATE Issued at 534 PM CDT Sat Apr 21 2018
Quick update for observed trends through 22 UTC. The CAM suite
through the 21 UTC HRRR iteration suggests the potential for
isolated showers across northwest North Dakota this evening in
association with the cold front currently across eastern Montana.
For now kept the forecast dry as moisture will be a limiting
factor for precipitation.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 156 PM CDT Sat Apr 21 2018
An upper level ridge moves east tonight as a shortwave trough
swings just north of us over Saskatchewan and Manitoba by Sunday
morning. We will transition to quasi-zonal through the afternoon
and evening, as a subtle ridge moves across the west late in
advance of a deepening West coast trough. Widespread highs in the
60s are in the forecast for Sunday afternoon.
.LONG TERM...(Monday through Saturday)
Issued at 156 PM CDT Sat Apr 21 2018
Models are in general agreement regarding the approaching trough.
As the associated upper low tracks across southeastern Montana and
southwestern North Dakota, rain chances will increase Monday
afternoon over the southwest, and eventually into the south
central by the overnight hours. There may be a brief period when
the rain mixes with light snow late, but little to no accumulation
is expected. There will be a tight pressure gradient associated
with this upper level shortwave that will be extending north
northeast from a surface low that will develop over northern
Wyoming before moving near the South Dakota Nebraska border. This
gradient will bring breezy northerly winds to the southwest and
south central Monday afternoon through early Tuesday morning.
Thursday, a dry cold frontal passage will bring a brief cool down,
mainly across the east. By the end of the week a fairly well
deified temperature gradient, from east to west looks plausible,
warmer to the west and cooler to the east. This may be more
pronounced than the Superblend guidance currently has due to the
Bias Corrected grids from the early April Temperatures. This
should sort itself out with time and opted to stick with the
Superblend, which may be cooler, at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 929 PM CDT Sat Apr 21 2018
A cold front across eastern Montana this evening will move across
North Dakota tonight. Dry and VFR conditions are expected through
Sunday. Will continue to monitor a low potential for strong
westerly winds at KISN late this evening behind the cold front.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PA
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...PA
Area Forecast Discussion
National Weather Service Cheyenne WY
948 PM MDT Sat Apr 21 2018
.UPDATE...
Issued at 941 PM MDT Sat Apr 21 2018
We are sending out a quick update to bring the fog in a little
earlier to areas west of the Laramie Range. Latest webcams are
showing some dense fog developing along I-80 between Cheyenne and
Laramie. However, the latest HRRR guidance does not show this fog
sticking around very long. At this point, we are not real
confident on how widespread the fog will be tonight. The valley
fog along the North Platte River still looks like a good bet, due
to upvalley flow developing in that area. The rest of the Nebraska
panhandle and parts of southeast Wyoming may end up being very
patchy, but dense in a few spots.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 230 PM MDT Sat Apr 21 2018
Forecast challenges deal with fog tonight into Sunday along with
rain chances returning Monday afternoon.
Currently...Upper low on water vapor imagery lays across western
Kansas this afternoon. Warp around moisture to the north and
northwest of this low brought some pretty good snow here at
Cheyenne this morning, but is quickly decreasing this afternoon.
IR imagery showing warming cloud tops across the Panhandle, so
would expect precip to come to an end later on this afternoon. Our
next system seen on water vapor imagery off the coast of northern
California at 1PM, still a couple days away.
For tonight into Sunday...A lot of low level moisture in place as
parts of the southern Panhandle received close to 3/4ths of an
inch of moisture and Cheyenne received close to a half inch. Soils
are wet. Low level winds are pretty light on forecast soundings in
the Panhandle and possibly here at Cheyenne, though GFS low level
wind directions not particularly favorable. Do have a low level
inversion setting up on forecast soundings, along with the
saturated soils. Can`t rule out fog tonight and introduced into
the forecast across much of the Panhandle, up the Platte River
valley to Douglas tonight. Here at Cheyenne, went with patchy fog.
HRRR guidance showing lower conditions developing overnight as
well, so confidence is moderate on this happening.
Next frontal system on track to begin moving into the area Monday
afternoon/evening. Precip becomes pretty widespread Monday evening
and have fairly high PoPs in the forecast for that time. Rain
changing to snow late evening into Tuesday morning as 700mb
temperatures fall to -7C across Converse/Niobrara Counties, -4C
here in Laramie County and -2C over the southern Panhandle.
Two last areas of concern are thunderstorms ahead of the front
Monday afternoon and wind behind the front. SPC has a General
Thunder area identified over southeast Wyoming and southern
Panhandle Monday afternoon. Lifted Indices down to -2C Monday
afternoon across the Panhandle with afternoon CAPE around 800
J/KG. Can`t rule it out and will add isolated Thunder to the
forecast Monday afternoon/evening ahead of the front.
Behind the front, GFS showing 850mb winds from the northwest at
35-40kts across the Panhandle and eastern Plains of southeast
Wyoming. Did increase winds from forecast guidance.
.LONG TERM...(Tuesday through Saturday)
Issued at 230 PM MDT Sat Apr 21 2018
Tuesday...Shortwave trough moves southward from northern Wyoming in
the morning to northern Colorado in the late afternoon. Expect
isolated to scattered morning showers associated with the shortwave
over our northeast half, and over the Nebraska panhandle in the
afternoon. Considerably cooler compared to Monday with cloud cover
and in the wake of the cold frontal passage.
Wednesday...Decent warming trend with a flattening ridge aloft and
with the flow aloft becoming northwest.
Thursday...Continued mostly dry, and cooler in the wake of a passing
cold front.
Friday...Dry northwest flow aloft prevails, with a warming trend as
700 mb temperatures rise to near 7 Celsius, yielding maximum
temperatures from the upper 50s to upper 60s at lower elevations.
Saturday...Continued mild as the ridge axis aloft moves overhead.
Isolated showers possible as some low and mid level moisture streams
northward from Colorado, though most locations will remain dry.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 551 PM MDT Sat Apr 21 2018
Main aviation headline overnight will be the lingering MVFR
conditions for CYS and western NE TAF sites along with an IFR to
patchy LIFR visibility drop 08-15Z due to fog development. HRRR
and NAM model guidance suggests pockets of dense fog being
possible, especially in the vicinity of the North Platte River
Valley early Sunday morning. Recent snow and rain has saturated
the near-surface layer and as temperatures cool overnight with
low winds across the high-plains, fog development appears likely.
Lower confidence in fog development for LAR/RWL as greater wind
mixing should reduce fog potential.
VFR conditions are expected after 14-17Z across all TAF sites
Sunday with general northwest winds at 10 to 15 knots for the
mountains and southeast winds across the NE Plains by the
afternoon.
&&
.FIRE WEATHER...
Issued at 230 PM MDT Sat Apr 21 2018
Minimal fire weather concerns as recent rain and snow has the
ground pretty much saturated across a large portion of the
forecast area. Rainfall amounts in the Panhandle range from a few
hundredths over northern portion with close to an inch south.
Across southeast Wyoming, our souther FWZs have seen close to a
half inch in FWZ 310 to well over a tenths west. Next wetting rain
event taking shape for Monday as another cold front moves into
the area from the northwest, spreading rain and mountain snow
towards the southeast through Monday night/Tuesday morning. No
hazardous fire weather conditions expected.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...REC
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...JSA
FIRE WEATHER...GCC
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
1058 PM CDT Sat Apr 21 2018
.UPDATE...
Front has cleared Travis county and cancelled Dense Fog Advisory for
this area. Dense fog continues south and east of Travis, and is
beginning to expand into eastern Bexar County. The front is
accelerating south and fog should lift across remaining counties in
the Dense Fog Advisory as the front passes through the area over the
next hour. The fog could linger across far southeastern counties
slightly longer after midnight.
&&
.PREV DISCUSSION... /ISSUED 1013 PM CDT Sat Apr 21 2018/
UPDATE...
Dense fog has increased enough in areal coverage to warrant a short
Dense Fog Advisory. The front will clear the Austin area between
now-1130PM and San Antonio between 1130PM-1 AM, at which time the
visibility will improve. The fog could linger across southeastern
counties slightly longer.
PREV DISCUSSION... /ISSUED 918 PM CDT Sat Apr 21 2018/
UPDATE...
Quick update to include a mention fog just ahead of the front.
As skies have cleared with departing convection to the east fog has
developed along and east of an Austin to San Marcos to Seguin line.
Some patchy dense fog is being reported. The fog could expand
southwest toward portions of San Antonio over the next couple of
hours ahead of the front. The fog will clear behind the front, which
is expected into the Austin area between 10-11PM and San Antonio
between 1130PM-1 AM. A few showers could develop along the front as
it reaches and moves east of I-35 and I-37.
PREV DISCUSSION... /ISSUED 635 PM CDT Sat Apr 21 2018/
AVIATION...
The line of storms that moved through the I-35 corridor earlier has
pushed eastward and cleared all of the TAF sites. Behind the storms
VFR conditions have prevailed, with only a few passing clouds. The
dryline currently extends from JCT (Junction) to ECU (Rocksprings) to
north of DRT (Del Rio) with the approaching cold front lagging
behind from MAF (Midland) to SJT (Dan Angelo) to just northwest of
DFW (Dallas/Fort Worth). The cold front passage will be the main
feature of this TAF package bringing with it a slight chance for
showers and a wind shift out of the north as it moves through the TAF
sites between 03z at AUS (Austin) and 05z at SAT/SSF (San Antonio/
Stinson). Winds will shift around to the north behind the front and
increase to between 10 to 14 knots overnight. Concerning
precipitation at the terminals the mention of VCSH has been left in
the AUS/SAT/SSF TAFs around the time of the frontal passage. Morning
high resolution models had isolated thunderstorms along the front
tonight, but recent runs of the HRRR and Texas Tech WRF have backed
off to show just some isolated showers. Beyond the frontal passage
and the overnight period clearing skies and north winds are expected
into Sunday.
PREV DISCUSSION... /ISSUED 244 PM CDT Sat Apr 21 2018/
SHORT TERM (Tonight through Sunday Night)...
The region is currently split into two different regimes with dry
conditions west of a dryline in the western counties and cloudy
conditions across the east in the moist sector. In the moist sector,
we are seeing areas of light rain and drizzle streaming to the
north-northeast and there are also some isolated showers and storms
moving to the east. The light rain/drizzle is developing below the
CAP in a moist layer between the surface and 725 mb and the showers
and storms are rooted above the CAP around 500 mb where some elevated
instability exist. This activity will all slowly shift east through
the early evening hours and will keep the higher PoPs in the 00-03z
time frame across the eastern counties. Dry conditions and 10 to 20
mph winds in Val Verde and Edwards County are leading to elevated
fire weather conditions.
After the warm sector activity shifts east late this afternoon and
early this evening, the focus will then shift to the approaching cold
front. Currently, the cold front is located near the Lubbock region
and will be entering our northern counties around 9-10 pm. High-res
models continue to show a broken line of showers and storms possible
along the front for areas mainly east of Highway 281 with the better
chances east of I-35. Will have 3 hourly PoPs between 00z and 12z to
account for the progression of the cold front. There is a marginal
risk of severe storms for areas north of a Llano to Austin to
Giddings line to account for frontal activity where CAPE values
should be around 1000 J/kg. Marginally severe hail or wind gusts
would be the main threat with any isolated severe thunderstorms.
After the cold front moves south by tomorrow morning, drier air will
filter into the region with clearing skies by morning. There should
be some high clouds moving into the area by the afternoon hours.
Highs tomorrow will not show any effects of the cold front with highs
expected to be in the middle 70s to middle 80s. The dry air will
allow temperatures to drop into the 50s for much of the area Sunday
night.
LONG TERM (Monday through Saturday)...
Northerly flow will remain in place for Monday and highs will be
similar to Sunday, in the upper 70s to middle 80s. Southerly flow
returns Tuesday and temperatures will respond with highs about 5-7
degrees warmer than Monday. Another trough will pass through the
Central Plains Tuesday night and will send another cold front south
into CWA Wednesday. The GFS is about 6-12 hours faster than ECMWF,
but both models show some rain chances along and behind this frontal
boundary. Will forecast 20-30 PoPs for the northern half of the area
in closer proximity to the upper level trough.
Previous runs of the GFS/ECMWF showed another front on Friday as
another progressive flow upper trough moves through the Plains. The
latest 12z run of the GFS has shifted the track of that upper low to
the north and keeps the front north of our area, while the ECMWF
remains persistent and brings the front with decent rain chances.
Will keep north winds in the forecast for now and PoPs capped at 20
percent until a consensus forms within the guidance.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 53 77 54 81 57 / 10 0 0 0 0
Austin Bergstrom Intl Airport 52 76 52 81 54 / 10 0 0 0 0
New Braunfels Muni Airport 53 78 53 82 55 / 20 0 0 0 0
Burnet Muni Airport 49 74 50 79 55 / 10 0 0 0 0
Del Rio Intl Airport 55 84 59 86 62 / 0 0 - - -
Georgetown Muni Airport 51 74 51 80 54 / 10 0 0 0 0
Hondo Muni Airport 53 83 54 84 57 / 10 0 0 0 0
San Marcos Muni Airport 53 77 52 82 55 / 20 0 0 0 0
La Grange - Fayette Regional 54 76 52 79 56 / 70 0 0 0 -
San Antonio Intl Airport 54 80 55 82 59 / 20 0 0 0 0
Stinson Muni Airport 55 80 56 83 58 / 20 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 1 AM CDT Sunday for Atascosa-Bexar-
Caldwell-Comal-De Witt-Fayette-Gonzales-Guadalupe-Karnes-Lavaca-
Wilson.
Dense Fog Advisory until midnight CDT tonight for Bastrop-Hays-Lee.
&&
$$
Mesoscale/Aviation...Treadway
Synoptic/Grids...Runyen
Area Forecast Discussion
National Weather Service Green Bay WI
1041 PM CDT Sat Apr 21 2018
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 304 PM CDT Sat Apr 21 2018
The latest RAP analysis and satellite/radar imagery show a large
high pressure system stretching from the mid-Atlantic states to
the western Great Lakes early this afternoon. Clouds continue to
stream into the southern half of Wisconsin ahead of a closed low
pressure system centered over the southern Great Plains. Radar
returns have been confined to far southwest Wisconsin, due to the
very dry air in place over the northern half of the state.
Speaking of dry air, humidities have fallen into the middle teens
over northern WI where sunshine and good mixing have supported
falling dewpoints through the day. As mid-level ridging moves into
the region, forecast concerns mainly revolve around temps and
dewpoints.
Tonight...High clouds will continue to sink to the south tonight
with the arrival of strong subsidence ahead of the mid-level
ridge. With high pressure remaining at the surface and little
change of the airmass in place, mostly clear skies and light winds
should result in another good radiational cooling night. Used a
blend of best performing guidance combined with last night lows
for temps tonight, which results in temps ranging from the upper
teens over northern Vilas county to the near 30 over the southern
Fox Valley.
Sunday...The storm system over the southern Plains will move east
into the mid-Mississippi Valley. The mid-level ridge axis will
hold firm over the northern Great Lakes, which will keep clouds
and any hint of precip well south of the region. Despite the full
sunshine, temps should not be appreciably different than today, as
the airmass changes little. The only difference will be the light
east wind developing which the sunshine should mitigate except
right near the Lake. So kept temps very similar to today`s
readings, except near Lake Michigan. Also dropped dewpoints
considerably during the afternoon, with min humidities falling
into the mid 20s across the northwoods.
.LONG TERM...Sunday Night Through Saturday
Issued at 304 PM CDT Sat Apr 21 2018
The warmer temperatures will continue to melt the snowpack
through the rest of the weekend and into next week. Some rivers
in the Wolf River basin currently at bankfull are forecast to
exceed minor flood stage as early as Monday morning. The next
chance for precipitation will move into the area on Tuesday
afternoon due to a shortwave trough and its associated cold front.
Another shortwave trough builds in behind it on Thursday.
For the start of the long term, a split flow pattern remains
dominate across the CONUS with an aggressive low pressure system
sweeping across the Middle Mississippi Valley, while the Upper
Mississippi Valley remains within a ridge of high pressure. By
Monday morning, the Upper Mississippi Valley will be on the
back side of the ridge as it begins to evolve into a zonal flow.
This pattern will allow temperatures to rise slightly above normal
for Monday to the lower 60s with the exception of the lakeshore
counties due to an onshore wind. These mild temperatures will
continue to chip away at the snowpack.
The flow evolves on Tuesday with the approaching shortwave
trough/cold front from the northwest. There is more uncertainty
amongst the models than yesterday with the evolution of this
pattern by Tuesday afternoon. The models are in agreement having
split flow occur with a closed low pressure system staying well
to the southwest of Wisconsin and a shortwave trough over the
Great Lakes. The disagreement comes in with the GFS. The GFS shows
a more aggressive development of these two waves of energy which
results in more lift and precipitation over the area. The ECMWF
and Canadian have the two waves of energy staying far enough
apart to have little influence over the area for Tuesday
afternoon and Tuesday night. As a result, a blend of the models
were used leaving some chance pops for rain showers over far
northeast and east-central Wisconsin Tuesday evening. With the
consistency of the split flow amongst the Canadian and ECMWF, it
is possible for the pops to lower again.
After the waves of energy exit the region, another shortwave
trough begins to enter the region on Thursday. Model guidance is
not in agreement with the timing of this shortwave trough causing
problems with p-type. The GFS and Canadian are in agreement with
the arrival for precipitation on Thursday morning and exiting by
Friday morning. The ECMWF has the shortwave trough entering the
area Thursday evening and exiting by Friday evening. Kept the
blended models chance pops across all periods due to the
uncertainty and will narrow down the exact time period later.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1041 PM CDT Sat Apr 21 2018
Some SCT-BKN cirrus clouds will track through the southern TAF
sites during the overnight hours. Further north clear to mostly
clear skies will prevail. VFR conditions will prevail over all of
the TAF sites through the period with light winds. The very dry
airmass in place has thus far prevented fog development during the
overnight hours, therefore there are no plans to put it in with
this set of TAFs.
&&
.HYDROLOGY...
Issued at 304 PM CDT Sat Apr 21 2018
Warming temperatures will continue to produce melting of the
current snowpack over northeast WI. This will lead to runoff and a
gradual rise of area rivers and streams. Several rivers are
expected to surpass bankfull this weekend and possibly flood stage
as early as Monday afternoon for the Wolf River basin. People
living near rivers and streams should keep a close eye on the
anticipated river rises and keep up to date on the latest river
forecasts.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Hykin
AVIATION.......Kurimski
HYDROLOGY......Hykin
Area Forecast Discussion
National Weather Service Blacksburg VA
905 PM EDT Sat Apr 21 2018
.SYNOPSIS...
High pressure will stay anchored from the Great Lakes to the
Middle Atlantic through Sunday night, while low pressure shifts
from the southern Plains and Texas to the lower Mississippi
Valley. This low will then track to the North Carolina and
Virginia coast by Wednesday.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 910 PM EDT Saturday...
At 01Z (9 PM EDT), surface high pressure was located across far
southeast VA/northeast NC with a dry airmass still firmly
entrenched across our region with the 00Z RNK sounding showing
0.35" PW values.
A canopy of high clouds will continue to drift over our area,
especially north of highway 460, keeping low temperatures
slightly warmer compared to the past couple of days. However,
with such a dry air mass in place and thinning cirrus in the
southern portion of our forecast area, brought down low temps a
few degrees closer to colder NAM MOS and HRRR guidance values.
For Sunday, an upper low will be in Arkansas, while an inverted
through extends northeast into KY, from a surface low over MS.
Anticipate some lowering and thickening of cloud cover through
the day, but no rain. With the clouds and southeast winds have
temps at or below mos, with upper 50s to lower 60s NC mountains
through the New River Valley into the Alleghanys/Greenbrier,
with mid to upper 60s elsewhere.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 245 PM EDT Saturday...
This portion of the forecast is looking more and more likely to be
one with plenty of wind and plenty of rain. A slow moving upper
level low pressure system will progress from the Lower Mississippi
River Valley northeast into parts of the Tennessee and Lower Ohio
River Valleys. The result for our region will be a developing
southeast flow into the region that will be tapping the Atlantic
Ocean for moisture, all while an in situ cold air damming wedge
develops. The rain, clouds and strong inversion will help keep
daytime temperatures on the cool side, and overnight lows near
normal for most of the region.
The southeast flow will be persistent during this period, and peak
in speed at 850 mb around 45 to 50 kts across the mountains Monday
night. The area defined by an area of between Bluefield, WV to
Marion, VA to Richlands, VA will likely be very gusty as this
orientation of a flow yields downsloping, mixing conditions
there outside the influence of the wedge. Currently, forecast
gusts in this area, and neighboring higher terrain, are in the
range where a wind advisory would be warranted, but we are too
early for any type of official product at this point. However,
the concern will be mentioned in the Hazardous Weather Outlook.
Another concern during this portion of the forecast will be the
potential for localized flooding Monday through Tuesday night and
then . Please see the HYDROLOGY section of this discussion for
details.
The precipitation will start to exit the region Tuesday night, but
not by a significant amount. Rather than having the region with
categorical POPs, we will start trending to more regions of
likely and chance POPs as the upper low continue a northern trek
into the Great Lakes region. This will help start veering winds
more southerly, and we will start to lose the strong Atlantic
moisture fetch.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 320 PM EDT Saturday...
The upper low over the Great Lakes will get caught up in the
northern stream jet, open as a wave, and eject eastward with the
prevailing flow. Its associated cold front/trough axis will cross
our region, and help bring winds around the the northwest Wednesday
into Wednesday night. This will result in our winds shifting
northwest, and allowing for upslope rain showers across the west,
and decreasing coverage of precipitation east of the Blue Ridge.
Our weather pattern will remain quite progressive through the
remainder of the forecast period. Two additional northern stream
shortwave troughs are expected to zip through the region. Each will
bring a return of showers to the area, with the greatest
concentration across the mountains. The first will be Wednesday
night into Thursday. The second will occur either Friday or
Saturday, as model agreement isn`t as strong on this second one. Our
forecast will reflect the quicker of the two solutions with enough
colder air arriving in its wake for the potential for some snow
showers along the highest peaks and ridges of southeast West
Virginia, south into the Northern Mountains of North Carolina.
Temperatures during this portion of the forecast will trend colder
with readings by Saturday some five degrees below normal.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
As of 730 PM EDT Saturday...
VFR conditions should be the rule through the forecast period as
high pressure is firmly in control. Expect increasing high
clouds into the overnight hours and tomorrow ahead of a low
pressure system moving in from the west. Over the course of the
day increasing moisture will lead to a thicker cloud deck and
some lowering. Winds will mainly be variable and light or even
calm through the nighttime hours. During the day Sunday, winds
should predominantly be from the southeast, however speeds
should remain light.
There exists some possibility for isolated precip in the
southwest section of the forecast area late in the TAF period,
but should remain far enough away to impact any of the TAF
locations.
High confidence for VFR conditions through the bulk of the TAF
period, with uncertainty growing near the end for small
potential to introduce MVFR conditions in the mountains.
Extended Aviation Discussion...
Clouds will thicken and lower by Sunday night in advance of an
approaching low in the Lower Mississippi River Valley. However,
cloud bases should remain VFR until deeper moisture arrives
Monday. SCT MVFR showers are possible in southern Virginia and
northern North Carolina Sunday night with rain becoming
widespread across the Mid Atlantic region on Monday. MVFR/IFR
ceilings and visibilities are expected Monday night and Tuesday
due to widespread rain and an upslope southeast wind. SCT MVFR
showers will continue into Wednesday.
&&
.HYDROLOGY...
As of 310 PM EDT Saturday...
Monday through Tuesday night, rainfall amounts over one inch are
forecast for the vast majority of the area, with locations along and
near the NC/VA border nearing two inches. Along and upstream of the
crest of the Blue Ridge, the strong southeast flow will yield
strong upslope enhancement with rainfall totals here possibly in
the two to three inch range with some isolated spots nearing
four inches. Flooding will be concern in the near term,
especially along the crest of the Blue Ridge within our forecast
area, and across parts of Southside Virginia and neighboring
sections of the Foothills and Piedmont of North Carolina. In the
slightly longer term, Tuesday into Wednesday, the GEFS based
SERFC Ensemble River Forecasts is offering a more likely than
not chance of some minor flooding along the Dan River as runoff
from this event travels downstream. While this statement does
not constitute an official forecast, it is a heads-up for an
above average potential for flooding within this river basin.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...WP
NEAR TERM...JR/PH/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...JR/WP
HYDROLOGY...DS