Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/21/19
Area Forecast Discussion
National Weather Service Grand Forks ND
751 PM CST Wed Feb 20 2019
.UPDATE...
Issued at 751 PM CST Wed Feb 20 2019
Made adjustments to overnight temps as lingering low clouds
will limit radiation cooling, and near term guidance (reflecting
current trends) now show more locations holding in the teens
through Thu morning. Light snow continues across much of our area,
with small pockets or narrow bands of moderate snow. Have held off
on any changes to current Winter Weather Advisory based on these
trends (still set to expire at 06Z).
UPDATE Issued at 554 PM CST Wed Feb 20 2019
Lobes of maximum divergence aloft showing weakening trends on
latest RAP analysis, however radar/satellite/obs indicate several
moderate band of snow still orientated west to east over our CWA.
Still expect a weakening trend for central and northern parts of
our CWA this evening, with potential for lingering light snow (or
flurries) overnight. Trends have improved enough with main areas
of snow far enough north to allow southern part of advisory to
expire on time at 6PM, and will continue to hold onto the rest of
the advisory for the evening period.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 321 PM CST Wed Feb 20 2019
Upper level trough was located over northwest IA with a trough
extending into ND. Southern end of trough will shear off toward
the Great Lakes tonight while northern end will also shear off but
will occur through Thu afternoon. Most of the snow will fall this
afternoon and will taper off tonight. Low to mid level low
pressure system will bring moisture into the area for tonight.
Weak east-west 700 theta-e ridge over the area will shift into the
northern valley and stall on Thu. Will keep winter weather
advisory going for this evening.
.LONG TERM...(Thursday night through Wednesday)
Issued at 321 PM CST Wed Feb 20 2019
Thursday night into Friday morning the next system within this
more active pattern lifts from southwest to northeast at 500mb.
Broad scale lift with q vector divergence above low and mid level
warm advection will bring widespread snowfall to the southern and
eastern areas Friday afternoon. Will continue to watch the western
edge as the 12Z EC remains a bit more west with its QPF compared
to the GFS/NAM ensembles. As the system approaches adjustments to
its coverage will be refined and much like todays system may end
up affecting more of the valley than currently forecast. Potential
banding from frontogenetical forcing still possible, though
currently appears transient at best, could add to the totals
though placement remains in question. Additionally model soundings
suggest ice aloft decreases with saturated lower layer creating a
freezing drizzle signature for the southern valley and lakes area
of west central MN possible Saturday morning.
Arctic front set to push through the region Saturday night into
Sunday morning with falling temps and strong winds creating some
patchy blowing snow in open country. How severely reduced visibilities
will be will yet need to be refined. Nonetheless the arctic airmass
will bring a return of single digit highs to the region for Monday
and Tuesday with lows in the teens to 20 below. Will keep the light
snow chances for Tuesday as a models bring a weak disturbance into
the northern plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 534 PM CST Wed Feb 20 2019
Main part of system is transitioning east, however light snow with
IFR/LIFR vis and CIGS 1200-3000 FT AGL continue across eastern ND
and northwest MN. A gradual improving trend south to north is
expected regarding VIS as snow continues to decrease in
intensity/coverage, however low CIGS are expected to continue
through the TAF period becoming IFR by midday Thursday. Winds will
tend to be light and variable through the TAF period or eventually
prevailing from the west-northwest around 5kt later Thursday as
low pressure transitions east and gradient remains weak.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Weather Advisory until midnight CST tonight for
NDZ027>030-038-039.
MN...Winter Weather Advisory until midnight CST tonight for
MNZ001>003-007>009-013>017-022>024-027-028-032.
&&
$$
UPDATE...DJR
SHORT TERM...JH
LONG TERM...JK
AVIATION...DJR
Area Forecast Discussion
National Weather Service Goodland KS
726 PM MST Wed Feb 20 2019
.UPDATE...
Issued at 721 PM MST Wed Feb 20 2019
Forecast remained generally on track as far as T, Td, Wind and Sky
grids were concerned with minor tweaks by way of raising
temperatures by several degrees to reflect incoming cloud cover
and come into better agreement with most recent model runs. Areas
of freezing fog were added to the extreme southwestern region
along and south of a line from SW Yuma County to Burlington,
Wallace, and Selkirk Kansas. Visibilities may drop below one half
mile in these areas of freezing fog. The GFS, NAM and the RAP were
all in agreement highlighting these areas for freezing fog
development.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 222 PM MST Wed Feb 20 2019
Continuing to warm up today with highs in the mid 30s and lows
overnight in the low to mid teens. Winds will be south around 10
mph with winds increasing to 10 to 15 mph to the south.
Closed low over the Great Basin will help in generating moderate
southwesterly flow aloft over our CWA. Along this flow we see a
shortwave ahead of the next system pushing across the Tri-State
area Thursday afternoon/ Thursday evening bringing in freezing
drizzle. Models are hanging onto some dryer air aloft, which will
inhibit snow development until overnight Friday, in the long term
forecast period. Temps will linger in the low 30s to upper 30s
throughout the day Thursday, so we will see a transition from
freezing drizzle to drizzle and back to freezing drizzle by
Thursday night.
There is a potential for fog / freezing fog development throughout
the evening Thursday and Thursday night with low level moisture
increasing from upslope flow from our southeast.
.LONG TERM...(Friday through Wednesday)
Issued at 100 PM MST Wed Feb 20 2019
Generally speaking, the long term period will continue to see
below normal temperatures and above normal precipitation. Most of
the precipitation will occur early in the period with the potential
for a significant winter storm Friday night and Saturday. There
will be another chance for light snow on Monday but it will be far
less impactful.
Will start off Friday morning with the potential for freezing
drizzle and freezing fog across northern and eastern parts of the
area. Shallow low level moisture return and weak upslope flow
ahead of the approaching system will result in light QPF, only a
few hundredths at worst, but with temperatures well below freezing
it will have an impact on travel. By mid day Friday, temperatures
should get above freezing and improve the situation.
Stronger system will begin to impact the area Friday night. Models
in fairly good agreement lending some more confidence to the
forecast. Shortwave trough will eject out of the Four Corners with
a closed upper low tracking from southwest Kansas to southeast
Nebraska Friday night and Saturday. This is a good track to bring
moderate to heavy snow and very windy conditions to the Tri State
area. There is the potential for widespread snow amounts in the 3
to 6 inch range with locally heavier amounts up to 10 inches
possible. In addition to the snow, as the surface low deepens
expecting very strong northwest winds to accompany the snow. It
looks like a classic set up for a blizzard in the central High
Plains. Will not hoist a watch at this time only because it is
still beyond the typical watch time frame, but will ramp up
wording elsewhere.
Winter storm should wind down Saturday afternoon and evening, with
perhaps some patchy blowing snow on the backside through about
midnight.
Remainder of the long term period will be relatively quiet, if
cold, with only the low chances for light snow on Monday with a
weak shortwave in the zonal flow aloft. Less than an inch is
expected at this time. Really see no chance for temperatures
returning to normal until late next week when the western ridge
finally starts to build across the Rockies.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 432 PM MST Wed Feb 20 2019
The forecast has been kept as VFR at both terminals throughout the
forecast period although there indicates some potential for sub-
VFR ceilings advecting in between 12Z-15Z with the southeasterly
wind flow. There may even be intermittent periods of slightly
reduced visibility from mist in association with the low-level
moisture present during hours of radiational cooling.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...SANDERSON
SHORT TERM...EV
LONG TERM...024
AVIATION...SANDERSON
Area Forecast Discussion
National Weather Service Blacksburg VA
1058 PM EST Wed Feb 20 2019
.SYNOPSIS...
A cold front will slowly move across the area overnight into
tomorrow finally allowing the surface wedge of cooler air to
erode by midday Thursday. Following the frontal passage
tomorrow, high pressure will build south over the area into
Thursday night. Rain returns by Friday and will remain in the
area until the next frontal passage on Sunday.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 830 PM EST Wednesday...
Have just about run the full suite of weather this evening with
a bubble high over ice/snow holding the wedge in place
resulting in more freezing rain. This while elevated instability
per warmth aloft seen on evening soundings helped convection to
the west make it into southwest sections. In addition, the
heavier rainfall from earlier combined with where temps have
warmed in the far west to combine with snow melt to result in
flooding/mudslides, and bankfull streams over the far west.
However it appears that the final slug of at least patchy rain
will be crossing back through the Blue Ridge over the next
couples of hours likely resulting in at least added patchy
freezing rain. Temps have jumped up in spots but given the true
surface warm front to the south, and the cold front will west
of the mountains, values have tended to topple back toward
freezing espcly eastern slopes and points north. Thus will keep
the winter storm warning and updated winter weather advisory
going for now. Appears since most readings are just around
freezing that added icing will be light espcly since falling
from such a warm layer aloft, but still enough to cause
problems with trees given the wet ground and elevated surfaces
such as bridges and overpasses. Otherwise just some added tweaks
to pops and to keep ice accumulation going longer this evening.
Still expecting temps to slowly rise per the latest HRRR but
given the stubborn wedge, it may be morning before spots from
BCB/ROA to LYH and points north trend upward.
Update as of 655 PM EST Wednesday...
With heavier precip exiting the southern end of the warning
area, that was set to expire at 7 pm, and temps slowly edging
up, decided to replace that area with an advisory to cover
added spotty freezing rain and residual impacts until midnight.
The remainder of the warning that runs until midnight remains in
place espcly given colder temps and the current band of precip
crossing the north. Otherwise bumped up pops and added more
thunder over the southwest this evening. Models continue to
struggle with the exodus of the wedge despite prelim values off
the evening sounding showing temps in the warm nose better than
+10 deg/C this evening. No added changes for now.
Previous discussion as of 300 PM EST Wednesday...
A cold front will approach the area overnight, increasing mixing and
eroding the wedge from west to east. The wedge will erode over the
mountains by midnight, but hang over the foothills and piedmont
counties through the early morning hours Thursday. While the wedge
is over an area, temperatures will remain in the lower 30s. Once the
wedge erodes, temperatures will warm to near 40F. Areas outside of
the wedge (Richlands and Chilhowie) have warmed into the 40s this
afternoon and may only drop a few degrees tonight. With temperatures
warming, precipitation overnight will turn to or stay a cold rain.
Rain will persist over the area tonight as a slow moving cold front
tracks over the region. If rain does stop, even briefly, areas of
fog and/or drizzle will take its place. The cold front is expected
to be near the Blue Ridge by 12Z/7AM, moving over the foothills
around noon, then exiting the piedmont during the afternoon. Rain
should end within an hour or two following the front. Rainfall
amounts overnight will range from a quarter to half of an inch. Some
concerns for flooding across SE WV as 1-2 inches of rain has fallen
today. Most of this water is being held by snowpack and could be
released with convective showers currently across Tennessee and
eastern Kentucky move over the area the evening.
Temperatures will warm into the 50s across the mountains to 60F east
of the Blue Ridge Thursday. A lingering wedge and rain may remain
over NC tomorrow. If this is the case, north-northwest NC
foothill and piedmont counties may only warm into the low to mid
50s.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 400 PM EST Wednesday...
Surface front which moves through the area Thursday will stall
just south of the region Thursday night as large area of High
pressure over the Bahamas and eastern Gulf of Mexico impedes
its progress to the south. This front will return as a warm
Front Friday into Saturday in response to backing flow ahead of
a vigorous upper level trough which is progged to move through
out of the Rockies Friday and into the Upper Mid-West Saturday.
Warm southerly flow will bring a conveyor belt of moisture
northward from the Gulf of Mexico with widespread precipitation
breaking out along and north of the warm front, and extending
west into the developing cyclone that will develop in advance of
the upper level trough.
Any brief drying Thursday night will be short-lived with clouds
and an opportunity for more rain returning to the forecast area
Friday and Saturday. Temperatures during this period are
expected to be above freezing.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 400 PM EST Wednesday...
A strong storm system is forecast to move through the Great
Lakes and into Ontario Sunday with a cold front trailing south
into the Appalachians. This front is forecast to cross the
mountains early Sunday, then east and off the Coast by Sunday
night, bringing an end to the rain. This will bring a surge of
strong post frontal winds that will linger into Monday before
diminishing.
The airmass ahead of the front is warm...so a brief spike in
temperature is anticipated Sunday, before we spiral back down
Sunday night and Monday as colder air advects across the region.
Temperatures by Monday will return closer to the mid/late
February normals.
High pressure will allow for a few days of drying before
precipitation chances increase again for mid-week.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
As of 1058 PM EST Wednesday...
Poor flying conditions to continue into the overnight with
mostly IFR cigs east and MVFR mountains as the low level wedge
of cool air weakens. However cant totally rule out a period of
VFR around KBLF where warmer air will mix out the low cloud
canopy sooner. Thus keeping the going trends going with cigs
mainly below 1K feet into later tonight, but perhaps rising to
MVFR within spotty rain into the early morning hours. Rainfall
should gradually taper off but will see areas of MVFR vsby as
fog settles in espcly where mixing is less overnight.
Late tonight, winds will gradually shift southwesterly as a
warm front lifts northward from the Carolinas, allowing warm air
aloft to finally reach down to the surface. The warm front will
be followed closely by a trailing cold front that will enter
from the west toward daybreak Thursday, shifting winds from the
west- northwest. It is this downslope flow that will result in
rapidly improving ceilings/visibilities beginning just after
12Z/7AM Thursday.
Extended Aviation Discussion...
A frontal boundary will meander around the region into the start
of the weekend, along with several areas of low pressure moving
along this boundary. This will keep the potential for
rain and sub-VFR conditions across the area through Sunday.
Should finally see improving conditions behind a passing cold
front Sunday night with VFR returning to start next week.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Winter Weather Advisory until midnight EST tonight for VAZ014-
017-018-022-032-033.
Winter Storm Warning until midnight EST tonight for VAZ019-020-
023-024-034-035-045>047.
NC...None.
WV...Winter Weather Advisory until midnight EST tonight for WVZ044.
Winter Storm Warning until midnight EST tonight for WVZ507-508.
&&
$$
SYNOPSIS...JH/RCS
NEAR TERM...JH/RCS
SHORT TERM...PM
LONG TERM...PM
AVIATION...JH/RCS