Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/14/19
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1041 PM EDT Wed Mar 13 2019
.SYNOPSIS...
An upper level disturbance will move northeast of the
region early this morning with the light snow and rain showers
north of the Capital Region ending. Above normal temperatures are
expected on Thursday and Friday, with showers likely ahead of a cold
front on Friday. Temperatures will return closer to normal levels
for the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 1040 pm EDT...A short-wave continues to progress across
southeast Quebec and northern NY, as heights continue to rise
upstream of the short-wave over the central and eastern Great
Lakes Region and the OH Valley.
Virga has been ongoing from the Capital Region south and east.
The 00Z KALY sounding is very dry below 11 kft AGL. Large sfc
T-Td spreads continue across the region. We kept some slight
and low chance POPs in for a few hours north and west of the
Capital Region. The local NYS mesonet cams indicated some light
snow accums across the southern Adirondacks. We have seen some
light rain amounts of a few hundredths in the west-central Mohawk
River Valley but temps remain above freezing. We have mainly
retooled the hourly weather grids for light rain/snow showers
Temps are having trouble wet bulbing further south with all the
dry low-level air. An isolated pocket of freezing drizzle is
possible, but at this point we will address with an SPS if we
get any reports. Based on the latest 3-km HRRR and NAM this
short- wave will not be much of a pcpn producer and it should be
north and east of the region after midnight. Temperatures will
also remain on the mild side and should only fall into the
upper 20s to lower/mid 30s overnight as mostly cloudy conditions
will persist.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Upper level ridging continues to build into the forecast area
on Thursday with temperatures warming well above normal. Thicker
clouds will be in place at daybreak but should erode throughout
the morning hours as the ridge axis moves overhead. Temperatures
should warm well into the 50s across most areas by the
afternoon.
Stronger upper energy and increasing low level jet convergence
approach our region Thursday night with rain reaching western
areas prior to midnight and all other areas by daybreak Friday.
A few rumbles of thunder may be possible in western areas but
model soundings show a pretty strong inversion in place. SPC
currently has the western areas in an area of general thunder
through daybreak Friday. Overnight lows will be even milder,
in the upper 30s to mid 40s.
Strong southwest boundary layer winds spread across the region
early Friday, resulting in a very mild day with rain showers.
Temperatures may warm into lower 60s in the valleys with low to
mid 50s in the higher terrain. The southwest winds may result
in some downsloping effects, limiting coverage of the showers.
Total QPF looks to range from a quarter to a half an inch of
rain throughout the day with highest amounts western areas.
Showers should exit the region Friday evening as winds turn more
out of the west, ushering in colder air.
Cold air advection continues Friday night, allowing for rain to
change back over to snow in the southern Adirondacks, Western
Mohawk Valley, Schoharie Valley and eastern Catskills. Snow
showers continue through the day in these areas as upper level
energy continues to move across the area. Temperatures Friday
night will be in the mid 20s to upper 30s, with high
temperatures on Saturday in the 30s to mid 40s.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The extended forecast will feature the return of the mean H500
longwave trough across the Northeast based on the latest medium
range and deterministic model guidance for late in the weekend into
the middle of next week with generally below normal temps for late
March.
Saturday night...A cold front and short-wave trough move across the
region with limited low-level moisture to work with. The best
chance of snow showers will be north and west of the Capital Region.
Some lake enhanced snow showers may produce some light snow accums
across the western Adirondacks, and the western Mohawk Valley. In
the cold advection in the wake of the front, it will get rather cold
with H850 temps falling to -12C to -16C based on the 12Z GFS. Lows
will fall back into the teens and 20s with a few single digits over
the southern Dacks.
Sunday...A brisk and cold day is expected with some lake effect snow
showers or flurries impacting the western Adirondacks. H850 temps
will continue to be 1 to 2 STD DEVs below normal based on the 12Z
GEFS. Highs will be in the mid 20s to lower 30s over the mountains,
and mid 30s to lower 40s over the hills and in the valleys.
Sunday night into Monday...Another short-wave in the cyclonic flow
within the H500 longwave trough moves towards and across the region.
There are some timing differences between the 12Z
GFS/ECMWF/Ensembles. This impulse once again does not have a lot of
low-level moisture with it, and it may produce some isolated snow
showers or scattered flurries mainly west of the Hudson River
Valley. It will remain cold with lows in the teens to lower 20s,
except single digits across the southern Adirondacks, and highs will
remain in the mid and upper 30s over the lower elevations to start
the week with a few lower 40s in the mid-Hudson Valley, and mid 20s
to mid 30s over the mtns.
Monday night into Tuesday...High pressure builds in from the Great
Lakes Region over NY and New England with fair, cold and dry
weather. The March sun angle should help out some, but still temps
will be running below normal with H850 temps of -12C to -16C. Lows
mainly in the teens to lower 20s once again with some single numbers
over the southern Greens, and southern Adirondacks. Highs will be
slightly below normal with 30s to lower 40s across most of the
region, but some upper 20s over mountains.
Tuesday night into Wednesday...The sfc high retreats offshore
Tuesday Night, as a clipper low moving across the Great Lakes
Region/Midwest may increase clouds and bring isolated to scattered
snow/rain showers north and west of the Capital Region based more on
the latest GFS/CMC and some of Ensembles late in the day. Temps
start to trend closer to normal by the mid week ahead of this system.
Overall, below normal temps and potentially below normal pcpn in the
extended.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
An upper level disturbance will move across northern NY and New
England tonight. A mid and upper level ridge will build in over
NY and New England tomorrow.
VFR conditions will prevail the next 24 hours ending 00Z/FRI at
KGFL/KALB/KPOU/KPSF. The upper level disturbance will generally
produce bkn cigs in the 5-6 kft AGL range at KALB-KPSF to KGFL
with mid-level clouds in the 8-10 kft AGL range. A VCSH
group was used at KGFL, but overall this disturbance has
produced a lot of virga. Further south, towards KPOU expect mid
and high level clouds to continue with cigs around 10 kft AGL.
The cigs at KGFL/KPSF will become scattered at 5-6 kft AGL
around noontime, with mid level clouds continuing at those sites
and KALB/KPOU. As the ridge builds in expect mainly high clouds
around for the duration of the afternoon at all the TAF sites.
The winds will be light and variable in direction at 4 kts or
less tonight. They will increase from the southeast at 5-10 kts
in the late morning into the afternoon. Low-level wind shear
may increase towards 00Z/FRI, but has not been included in the
TAFS yet.
Outlook...
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: High Operational Impact. Likely SHRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Low Operational Impact. Breezy Slight Chance of SHRA.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: Low Operational Impact. Slight Chance of SHRA...SHSN.
&&
.FIRE WEATHER...
Temperatures will be mild overnight as an upper
level disturbance brings the chances for a passing rain shower or
some spotty freezing rain. Above normal temperatures are expected on
Thursday and Friday, with showers likely ahead of a cold front on
Friday. Temperatures will return closer to normal levels for the
weekend.
RH values will be at or above 40 percent through Friday. Winds
will be south to southeast at less than 15 mph today through
Thursday. Winds turn to the west Friday evening and become
breezy.
&&
.HYDROLOGY...
Late this afternoon and evening, some very light
precipitation in the form of rain and freezing rain will pass
through northern areas during the evening hours and into the
first part of the overnight. Total liquid equivalent will be
under a tenth of an inch and this precipitation will have little
to impact on area rivers and streams.
Behind this system, mainly dry weather is expected on Thursday,
along with much milder temperatures. This will allow for some
snowmelt across the region. Temperatures will remain mild for
Thursday night into Friday, which will continue to allow snow melt
to occur. There still is some uncertainty just how much snow melts
occurs, as the snow pack is still very cold across high terrain
areas and will need to ripen before it can melt. Some rainfall is
also expected on Thursday night into Friday, which will also
contribute to the runoff, but amounts look to mainly be under a half
inch.
While the combination of snow melt and rainfall should allow for
some rises on rivers and streams, it may not be enough to cause
rivers to reach flood stage. The latest MMEFS show a few river
points have about a 30% chance of reaching flood stage, and this is
mainly due to the model showing some aggressive melt of the snowpack
across the Adirondacks which may not occur. As of right now, river
flooding due to rainfall/snowmelt looks to be a limited threat for
late this week.
While snowmelt flooding doesn`t appear likely, we cannot totally
rule out localized flooding due to ice jams. River rises could
allow for some ice to move, and it`s always possible this time of
year that ice gets stuck in a particular spot that can cause a
localized backup of water. The threat for ice jam flooding appears
to be highest Friday and perhaps lingering into the weekend. Colder
and drier weather returning this weekend should help limit any
additional runoff for this weekend.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...JLV/Wasula
NEAR TERM...Wasula
SHORT TERM...NAS/JLV
LONG TERM...Wasula
AVIATION...Wasula
FIRE WEATHER...JLV
HYDROLOGY...JLV
Area Forecast Discussion
National Weather Service Bismarck ND
953 PM CDT Wed Mar 13 2019
.UPDATE...
Issued at 950 PM CDT Wed Mar 13 2019
Tweaked POPs again as they were too high mid to late evening
across much of western and a good chunk of central ND. Most of the
snowfall has been confined to far south central ND and into the
James River Valley. Snow should expand north and west with time
tonight.
We continue to struggle to saturate west and north of the main
area of snow. KBIS radar depicts a solid 2500 ft layer of dry air
still to work through as of 930PM. This area is decreasing so
precipitation should eventually result. 00Z high resolution
models (ARM/NMM) along with the latest NAM have pushed the heavy
snow area farther east, now in the 2-4 inch range for the
southwest and south central. Far south central ND still has 6-8"
with the higher totals over the James River Valley. Latest
HRRR/RAP are advertising very similar numbers for the areas above.
Thus the high forecast snowfall totals were maintained far south
central and across much of my southeast (James River area), but
we decreased forecast snow amounts elsewhere by on average 3
inches, including for Bismarck/Mandan. Regardless of this
decrease, with the strong winds still expected to develop now
through the overnight, blizzard conditions will develop so our
headlines will remain as is with this update.
UPDATE
Issued at 658 PM CDT Wed Mar 13 2019
Slowed the northward expansion of POPs a bit, utilizing the HREF
and CONSSHORT models, which seem to have the best grasp of
current radar imagery and reports. Headlines remain valid. Have
had reports from both the Dickey and LaMoure county Emergency
Managers of visibilities from less than 1/2 mile to a couple of
city blocks within urban areas. Conditions will further
deteriorate through this evening to the west and north as snow
moves in and northerly winds increase.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 242 PM CDT Wed Mar 13 2019
Developing blizzard conditions south and east late this afternoon
and into the night highlight the short term.
Latest satellite imagery presents a gorgeous and textbook example
of a mid-latitude upper level cyclone centered near the
intersection of Colorado, Nebraska, and Kansas. At the surface,
low pressure continues to undergo explosive cyclogenesis over
western Kansas with a RAP analyzed closed contour of 972 hPa.
As the entire system starts to pick up speed and move northeast,
the surface low will begin to fill, the storm will become more
vertically stacked and the pressure gradient will tighten over
western and central North Dakota.
Strong upper level Q-Vector convergence rotates catawampus into
the southwest and south central after 00z Thursday. Two distinct
flavors of forcing are being advertised through 12 UTC Thursday
per the 12 UTC iteration of today`s GFS. A large uniform area of
decent mid level frontogenesis collocated with strong omega in the
dendritic growth zone will be the primary mechanism for
accumulations across the west and the central with the exception
of the south central. Further south and east, strong frontogenesis
in the lower levels will be collocated with very strong omega in
the dendritic growth layer. This is the area that will extend from
somewhere in Sioux county, northeast through Logan county, to
Stutsman and Foster counties. These areas and east will see the
best signals for banded snow and will be characterized by steeper
mid level lapse rates that points further west. This band will
likely see totals ranging from 8 to 14 inches with isolated
pockets of greater accumulations. Elected to trend the edge of
this relatively narrow band a bit further west than most guidance
as western QPF associated with the more uniform synoptic forcing
appears to be a bit underdone. The other complicating factor will
be some mid level dry air intruding over Dickey and LaMoure
counties overnight, bringing the potential for some freezing
drizzle and perhaps a local minimum in snowfall totals if and
where the intruding dry slot sets up and ice aloft is lost.
Considerable uncertainty remains regarding the western gradient of
the precipitation shield. The Bismarck/Mandan corridor has
consistently been near or right on top of this gradient, thus a
slight wobble on track could vastly alter snow amounts there.
Still, even a few inches of snow will create widespread blizzard
conditions when coupled with 55 to 65 mph wind gusts. These values
seem reasonable analyzing potential momentum transfer using 12
UTC BUFKIT soundings across the south central and eastern portions
of our area.
Synoptic forcing for large scale ascent becomes more diffuse
through the day on Thursday and the snow will gradually taper.
Gusty winds will remain in place through much of the day and
blizzard conditions across the south central and east will be
slow to relax. By the late afternoon, light snow will linger but
winds will slowly start to abate.
.LONG TERM...(Thursday night through Wednesday)
Issued at 242 PM CDT Wed Mar 13 2019
BLizzard conditions continue to diminish Thursday evening from
west to east. A few weak clippers follow overnight, late Friday
night through Saturday, and another Sunday. However little or no
significant weather will come of these, other than low end
precipitation chances from the Turtle Mountains south into the
James River Valley. High temperatures will remain in the 30s
through the extended period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 658 PM CDT Wed Mar 13 2019
Accumulating snow combined with strong winds will lead to blizzard
conditions at KBIS and KJMS by 06z this evening. Although
blizzard conditions are not expected at KDIK, visibilities will
still be significantly reduced down to 1/2 mile at times. Very
little to no accumulating snow is expected at KMOT and KISN with
visibilities remaining VFR. Widespread MVFR/IFR ceilings.
Conditions improve Thursday morning into Thursday afternoon from
west to east.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 1 AM CDT /midnight MDT/ to 10 AM
CDT /9 AM MDT/ Thursday for NDZ012-019-021-033-040.
Blizzard Warning from 1 AM to 1 PM CDT Thursday for NDZ005-013.
Blizzard Warning until 7 PM CDT /6 PM MDT/ Thursday for NDZ036-
037-045>048-050-051.
Blizzard Warning until 1 PM CDT /noon MDT/ Thursday for NDZ020-
022-023-025-034-035-041>044.
&&
$$
UPDATE...NH
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...NH
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1030 PM EDT Wed Mar 13 2019
.SYNOPSIS...
High pressure will move off the east coast tonight. A cold front
approaching from the west on Thursday should reach the mountains
Thursday night and cross the region on Friday. Dry high pressure
will then follow for the weekend. A weak cold front will arrive
from the northwest early next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1020 pm EDT: A highly amplified flow pattern will remain in
place tonight as the major cyclone over the plains slowly lifts
northeast while the downstream ridge axis moves over the eastern
seaboard. Well ahead of this system, and the associated surface
cold front advancing east across the Mississippi River Valley,
the southerly to southwesterly 850 mb jet will ramp up across the
southern mountains overnight, with 40+ kt speeds likely ariving
after 06Z. Expect breezy to windy conditions to develop. With
this update, wind gust potential was re-evaluated. It is limited
by the warm-advective nature of the winds, but some of the higher
elevations may be more directly exposed to the winds within the
jet. HRRR guidance seems to capture a minor mountain-wave wind
event, with notably stronger winds on the Tennessee side of the
mtns. With lack of support from the model guidance that normally
might indicate significant gusting, we will continue to advertise
advisory-level gusts only at elevations above 4000 feet, and
sparsely even at that elevation. Hence no Wind Advisory appears
warranted.
Isentropic lift and southern mountain upslope flow will increase
through the morning hours, with solid chance PoPs for light showers
indicated by daybreak. Per latest meso model output and relatively
shallow nature of the moist layer, the onset of overnight PoPs
has been slowed down a bit, but there remains reason to believe
chances increase more rapidly in the morning.
Expect a strengthening, deep-layer southwesterly flow to develop
through the day on Thursday as the filling central CONUS system
lifts to the Great Lakes and the associated cold front pushes east
toward the southern Appalachians. Despite the offshore surface high
position, cannot rule out some shallow, weak surface wedging as the
upglide improves a bit from the west and a nose of surface high
pressure persists east of the mountains. However, precipitation
over the piedmont is questionable and the guidance sources all
have southerly flow at the surface, so will only shade temperatures
slightly toward the cooler end of the guidance envelope. Will also
keep a sharp PoP gradient going late day as the southern mountains
experience deepening upslope flow and moisture, while the I-77
corridor stays relatively dry. Any sbCAPE should be limited to
far southern and southwestern sections late Thursday afternoon,
where little more than isolated thunder should be possible.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 230 PM EDT Wednesday: The short term picks up at 00z Friday
with a deep cyclone tracking NE across the Great Lakes dragging a
cold front across the Ohio to Lower MS valleys. A band of convection
is expected to be along/ahead of the front approaching the southern
Appalachians Thursday evening. The better dynamics looks to stay
north of the area, and only a few hundred J/kg of MUCAPE is expected
to push into the western Carolinas ahead of activity from the south.
So I expect mainly showers and perhpas a few weakening thunderstorms
to enter western NC overnight Thursday night, struggling to survive
to the eastern escarpment by daybreak Friday. A SWLY 40-50 kt LLJ
will provide strong upslope forcing and pool 1.0-1.5" pwats into the
NC mountains and NE GA. So a quick 1-2" of QPF is possible in these
areas, which should be well under FFG. With that said, a non-zero
excessive rain threat will exist in these areas. Elsewhere, it will
be a mild night under cloudy skies and spotty light showers.
The front will cross the area during the day Friday. Much like the
previous front, the air mass ahead of the front will struggle to
destabilize until it gets mostly east of the CWFA. The NAM is a slow
outlier, and has 500-1000 J/kg of sbCAPE across most of the NC/SC
piedmont by 21z Friday. But all the global models show at least a
few hundred J/kg along the I-77 corridor. So some redevelopment/
strengthening convection looks possible before the line exits to the
east. Bulk shear will be on the order of 40-50 kts, but mostly
unidirectional. So the severe threat looks low at this time. Temps
will be tricky Friday, as CAA ramps up in the mountains, while the
piedmont sees downslope warming after very warm morning lows. Will
go with superblend for now, but may need to bump up maxes in the
east, if the front`s exit is any slower. Highs ranging from upper
50s along TN border to lower 70s in the extreme SE.
Friday night, shallow moisture will bank up against the NC/TN border
areas within NW flow. A few sprinkles/flurries may be seen
overnight, but accums are unlikely. Then cool and dry high pressure
builds in from the west on Saturday under a deepening trough aloft.
Min temps will still be a couple categories above normal Friday
night, but then temps return to slightly below normal for highs
Saturday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 130 PM EDT Wednesday: A stg ulvl trof will continue to develop
across the ern CONUS to begin the period. The guidance is still at
odds wrt the amt of mlvl energy diving toward the FA Sun
night...however there is now better agreement seen btw the GFS/CMC
solns. At any rate...have maintained the slgt chc PoPs with precip
continuing thru the daytime Mon. The p/type looks to either be snow
or rain which is common with the alignment of this type of pattern.
Currently have a mix of -ra/sn to begin then likely all snow aft 06z
before changing back to rain as the llvls warm arnd mid-morning. No
sigfnt accums are expected with this feature. Strong Canadian hipres
will build in quickly Mon and keep the atmos rather dry thru Wed.
This new airmass mix will also maintain temps a bit below normal.
There could be a more organized system developing off the Atl coast
just past the fcst period and right now it looks cold enuf to
support wintry weather over most of the FA. The details of this
system will be worked out over the next several days.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR this evening under mainly cirrus cigs;
these may thin as upper ridge axis moves past the region. Overnight,
however, low-level southerly flow will amplify ahead of frontal
system moving thru the Mississippi Valley. This will saturate a
layer and introduce a restrictive cig, first in the upslope areas
near the Blue Ridge Escarpment--hence warranting MVFR at KAVL soon
after midnight--and later in the morning at all sites except KCLT,
where cigs should remain low VFR. Diurnal mixing is expected to
result in eventual lifting of cigs back to VFR, except at KAVL, as
a result of the upslope enhancement. Isentropic lift will continue
and a chance of precip is introduced early in the morning at KAVL
and during the aftn elsewhere, except at KCLT.
Outlook: Moisture and associated restrictions will be greatest
Thursday night through Friday as a cold front approaches and moves
through the region. There is a small chance of thunder Friday east
of the mountains. Dry weather will develop over the weekend and
likely persist into early next week.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 90% High 100%
KGSP High 100% High 93% High 87% High 98%
KAVL High 100% High 89% High 86% High 95%
KHKY High 100% High 89% High 84% High 95%
KGMU High 100% High 89% High 87% High 95%
KAND High 100% High 93% High 86% High 90%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...HG/Wimberley
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...Wimberley
Area Forecast Discussion
National Weather Service North Platte NE
1020 PM CDT Wed Mar 13 2019
.UPDATE...
Issued at 1020 PM CDT Wed Mar 13 2019
Just sent out an evening update to address the ongoing snow and
wind situation across western and north central Nebraska. For
starters, made a couple of changes to the headlines and they are
as follows: Added Custer, Garfield, Wheeler and Holt counties to a
blizzard warning and removed Custer county from the high wind
warning as a blizzard warning should cover both the wind and snow
threat. The latest model solutions this evening develop a band of
precipitation on the western periphery of the surface low
overnight and sustain this into Thursday morning. There is decent
agreement between the HRRR and NAM12 solutions developing the
western edge of this band of precipitation from eastern Custer
into Garfield, Wheeler and eastern Holt counties. Snow fall
amounts will not be huge with this band, however, the latest short
term solns indicate the strongest H85 winds (60+ KTS) developing
from Boyd county, south to Garfield and Wheeler counties Thursday
morning. If the 2 to 5 inches of snow can materialize as indicated
in the models, conditions will be very bad across these areas
Thursday morning. Finally, went ahead and removed Custer county
from the high wind warning as the weather hazards will be covered
with the newly issued blizzard warning.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 403 PM CDT Wed Mar 13 2019
The center of a very impressive mid latitude cyclone is located
across western KS this afternoon. The surface low associated with
this is near 970 mb. A mid level dry slot has advanced north into
southern/eastern portions of Nebraska, allowing for a break in the
rainfall. Farther west, across western and portions of north
central Nebraska, an intense band of heavy snow is occurring
within the deformation zone on the northwest side of the system.
Along with the snow, very strong winds have developed and will
continue through tonight and into Thursday. The snow band across
northwest Nebraska will slowly weaken tonight, but blizzard
conditions will continue all night and into at least Thursday
morning due to the very strong winds.
The other aspect of this system is the widespread flooding that is
occurring across central and eastern portions of the state. As the
system occludes this afternoon, scattered thunderstorms will develop
across portions of north central KS and southern and southwest
Nebraska. These will wrap back to the northwest and form a new
narrow deformation band this evening. This will change over to snow,
with 2 to loaclly 5 inches possible within this band to the east of
Highway 83. Winter Storm Warning is in effect for this area due to
the combination of snow and blowing snow.
Strong damaging winds will be the other factor in this storm system.
Gusts of 60 to 65 mph will remain possible through the day Thursday.
.LONG TERM...(Friday through Wednesday)
Issued at 403 PM CDT Wed Mar 13 2019
High pressure builds in Friday leading sunny skies and highs ranging
from the mid 30s across the Sandhills to mid 40s south of I-80,
which will be roughly 15 to 20 degrees below seasonal norms. With
high pressure in place for the weekend, temperatures will moderate a
bit but are expected to remain at or slightly below seasonable norms
with h85 temperatures running a bit cool. Winds will be light making
for pleasant conditions with highs climbing into the upper 30s to
lower 50s from north to south. Our next chance for precipitation
arrives late Monday into early Tuesday with the approach of a
frontal boundary associated with a clipper system. The ECMWF has
backed off a bit and pushed most precipitation south of the area
while the GFS is quicker with its solution and clips areas south
of I-80 early Tuesday morning. Both models indicate temperature
profiles favorable for a rain/snow mix but QPF looks to be light,
limiting any potential snow amounts. There does not appear to be
much of a cold surge with this system, so little change is
expected in daytime highs between Tuesday and Wednesday with highs
generally near 40 in the northern Sandhills to near 50 across
southwest Nebraska.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 638 PM CDT Wed Mar 13 2019
For the KLBF terminal: Expect periods of IFR conditions this
evening into the early overnight hours as snow and blowing snow
impacts the terminal. Visbys may drop periodically under a half a
mile through mid evening. Very strong northerly winds are expected
over the next 24 hours with frequent wind gusts between 40 and 50
KTS. For the KVTN terminal: Expect LIFR conditions this evening as
blizzard conditions impact northern Nebraska. Conditions will
begin to slowly improve overnight, however, visibilities will
range from 1-2 miles with very strong northerly winds gusting as
high as 50 KTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 9 AM CDT /8 AM MDT/ to 7 PM CDT /6 PM
MDT/ Thursday for NEZ025-026-036-037-057>059-069>071.
Winter Storm Warning until 9 AM CDT /8 AM MDT/ Thursday for
NEZ025-026-036-037-057>059-069>071.
Winter Storm Warning until 7 PM CDT Thursday for NEZ006>009-027.
Blizzard Warning until 7 PM CDT /6 PM MDT/ Thursday for NEZ004-
005-010-022>024-028-029-035-038-056-094.
&&
$$
UPDATE...Buttler
SHORT TERM...Taylor
LONG TERM...Jurgensen
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
922 PM EDT Wed Mar 13 2019
.SYNOPSIS...
High pressure will move offshore through Thursday. Strong low
pressure will move northeastward across the Great Lakes Thursday
night, then into Canada Friday. A warm front will approach from the
Carolinas Friday morning, quickly followed by a cold front
approaching from the Ohio Valley Friday afternoon. High pressure
will follow for the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
High pressure will continue to move offshore through tonight. A
weak shortwave rounding the ridge aloft combined with
isentropic ascent is resulting in a fairly solid deck of mid
level clouds. So far, sprinkles are remaining in Pennsylvania,
so may be able to trim this mention from the forecast grids a
bit.
Light south to southeast flow will continue through the night
and will combine with the cloud cover to limit temperature falls.
Some areas are calm, and when the mid clouds exit and leave
thinner cirrus, some spots could drop into the 30s. Otherwise
lows in the 40s can be expected.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As high pressure continues to drift into the western Atlantic, a
strong area of low pressure will move northeastward across the
Great Lakes Thursday into Thursday night. A fair amount of mid
and high level cloudiness is expected to continue moving
overhead well in advance of this system.
The associated warm front will move northward toward the region
from the Carolinas Thursday night. Strong warm air advection in
the low levels should result in at least scattered showers
making there way east of the mountains during the second part of
the night. Temperatures will be quite mild, well into the 60s to
near 70 Thursday and staying in the 50s Thursday night. Some fog
seems likely near the tidal Potomac and Chesapeake Bay as dew
points rise above the colder water temperatures.
The warm front will lift northward across the area Friday
morning, quickly followed by a cold front approaching from the
Ohio Valley Friday afternoon. There may be a break in
precipitation between the fronts, before daytime heating leads
to the development of more showers near and east of the Blue
Ridge during the afternoon and early evening hours. With the
milder temperatures and higher humidity, there is expected to be
a few hundred joules of CAPE, mainly east of I-95, which could
result in an isolated thunderstorm or two. There is a fair
amount of shear, but the mid and upper support is well removed
from our area. Any more organized showers or a thunderstorm or
two will have to be reliant on modest instability and surface
convergence along the front. Therefore, widespread organized
convection is not anticipated, though some gusty winds are
possible in any heavier showers along the front.
Highs may again approach 70 Friday, but there`s questions as to
how much precipitation and cloud cover will allow temperatures
rise. Some scattered upslope snow showers are possible along the
Allegheny Front Friday night as temperatures cool. Lows will
drop into the 40s east of the mountains, to around freezing over
the higher elevations.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A cool but mostly dry pattern is expected during the long term.
At the start of the period, a cold front will be pushing east
off the coast, with cool but dry northwest flow dominating. Some
upslope rain/snow showers are expected in the mountains, but
elsewhere, little if any precip is expected. A broad trough will
settle over the region and remain through Tuesday. While weak
disturbances will work across the region, the frontal boundary
will remain well to the south and east, keeping moisture limited
and limiting any surface development. Will need to watch for
any potential stronger disturbances which could result in
cyclogenesis, but at least through Tuesday the odds of any
significant coastal low pressure development affecting our
region appear low.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Southerly winds expected through Friday, with daytime gusts of
around 20 knots possible. Mainly VFR through Thursday, although
some guidance indicates MVFR clouds could approach CHO as early
as Thursday morning as moist flow pushes into the Blue Ridge.
Some fog is possible near terminals adjacent to larger bodies
of water (dew points rising above colder water temperatures)
Thursday night. Sub-VFR ceilings also likely develop Thursday
night and persist into Friday as a warm front lifts northward
from the Carolinas. A cold front will quickly follow from the
Ohio Valley by Friday afternoon as the parent surface low moves
from the Great Lakes into Canada. Some showers and perhaps a
thunderstorm are likely during this time (best chance of thunder
near/east of I-95). Gusts 20-30 kts possible along the front
Friday afternoon. Winds behind the front become NW Friday night.
VFR should prevail over the weekend, though the northwesterly
flow may gust 20-30 knots at times, especially on Saturday.
&&
.MARINE...
S/SE channeling was resulting in numerous 20 kt gusts during the
late afternoon hours along the western shore of the Bay south of
the Bay Bridge and downstream from Dahlgren on the Potomac, so
a Small Craft Advisory was issued until midnight. There seems to
be enough decoupling that the winds are generally trending to
15 kt or less. May be able to cancel the Small Craft Advisory
early, although it`s worth noting the HRRR model keeps winds
elevated past midnight.
Southerly flow will likely have trouble mixing down over
relatively cooler water as milder air moves in, at least until
the gradient increases markedly ahead of an approaching frontal
system Thursday night into Friday. However, with the upper tidal
Potomac being narrower and the fetch coming from land instead of
water, have issued a Small Craft Advisory from noon until 6 PM.
It`s possible that this may need to be expanded as models are
indicating 12-15 kt sustained winds, but did not have the
confidence to issue due to the factors listed above and
presentation of NAM forecast soundings at NHK. Likewise,
uncertainty in the amount of mixing and magnitude of gusts
continues into Thursday night, though a SCA could be required
for parts of the waters.
Some fog, possibly dense, is likely over the waters as dew
points rise above the water temperatures Thursday night into
Friday. Showers and perhaps a gusty thunderstorm or two are
likely Friday afternoon.
SCA possible, especially Saturday, but winds likely diminish a
bit Sunday.
&&
.TIDES/COASTAL FLOODING...
Southerly flow will result in rising tidal anomalies through
Friday, which may lead to near minor flooding (highest forecast
tides will be during the day Friday). Winds will turn to
northwesterly behind a cold front Friday night, causing
anomalies to decrease.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ532>534-
536-537-542.
Small Craft Advisory from noon to 6 PM EDT Thursday for ANZ535-
536.
&&
$$
SYNOPSIS...DHOF
NEAR TERM...ADS
SHORT TERM...DHOF
LONG TERM...RCM
AVIATION...ADS/RCM/DHOF
MARINE...ADS/RCM/DHOF
TIDES/COASTAL FLOODING...DHOF
Area Forecast Discussion
National Weather Service Marquette MI
813 PM EDT Wed Mar 13 2019
.SHORT TERM...(This evening through Thursday)
Issued at 437 PM EDT WED MAR 13 2019
Water vapor imagery and RAP analysis show a trof over the Rockies
with a strong shortwave/mid-level low over far nw KS. At the sfc, a
~971mb low was along the CO/KS border, unusually deep and a
potentially record breaking low pres for that part of the country.
Ahead of the system, southerly flow has transported abundant
moisture n thru the Plains with 12z soundings showing anomalously
high precipitable water values of 300-375pct of normal across the
central Plains. Closer to home, shortwave that brought -shra to the
area last night is heading into southern Quebec. In its wake, it`s
generally been a dry day across the fcst area. Fog has not been too
much of an issue today. Fog has been most persistent and locally
dense around the northern end of the Bay of Green Bay e to KISQ/KERY
vcnty. Vis satellite imagery has shown low clouds thinning in the s
wind downslope areas near Lake Superior. Current temps are in the
mid 30s to the mid 40s.
Aformentioned system over western KS has already reached peak
intensity and will be weakening as it lifts ne, reaching the western
Great Lakes region Thu evening. A couple of shortwaves lifting out
ahead of the main wave will bring 2 periods of more organized shra
to the fcst area thru Thu morning. The second wave, passing Thu
morning, will be notable stronger than the first wave arriving this
evening. Resurgence of isentropic ascent/moisture transport with the
first wave should bring sct/nmrs shra from s to n across the fcst
area this evening. Forcing tends to strengthen with time, so greater
coverage of shra will probably occur across the n and in particular
the nw where moisture transport remains more focused. Pcpn should
then diminish for a time before increasing again overnight ahead of
the next approaching, stronger shortwave. Pcpn fcst on Thu is a
little more nebulous, but seems that there would be a diminishing
trend in shra late morning into the mid aftn before some increase in
shra again late in advance of the decaying/former mid-level low.
With some instability aloft, not out the question that there could
be a few rumbles of thunder, especially late tonight/Thu morning in
association with the stronger shortwave. Expect low temps tonight in
the mid 30s to around 40F. There may be some tendency for temps to
rise overnight. Highs on Thu should be mostly in the upper 40s/lwr
50s, colder near Lake MI. If there are any breaks in the clouds,
temps could rise well into the 50s. Fog could become quite
widespread and locally dense at times tonight into Thu as even
higher dwpts advect into the area.
Have maintained going flood watch. Broadly, expect one-third to two-
thirds of an inch of rainfall tonight/Thu. There will probably be
locally higher amounts where heavier shra track. At this point,
would expect main issues to be with ponding of water on roads near
ice/snow packed storm drains and any stretches of road where deep,
extensive snowbanks along the shoulders prevent normal water
drainage off the roads. Water seeping into basements will also be an
issue. Small streams impacted by any heavier showers could see rapid
rises in water levels.
.LONG TERM...(Thursday night through Wednesday)
Issued at 354 PM EDT WED MAR 13 2019
Models show the big system currently over the Central Plains
beginning to unravel as it passes overhead Thursday evening at the
start of the long-term period. It quickly lifts off to the northeast
through Thursday night and its cold front surges southeastward
across Upper Michigan. It looks right now like the precip forced by
the cold front will be primarily rain but may end as wet snow, with
amounts generally expected to be less than an inch, except perhaps 2-
3 inches for the Porkies and Ironwood. A secondary short wave
dropping down behind the main vort lobe will keep scattered snow
showers going into Friday morning and account for another 1-3 inches
during the day Friday over the higher terrain of the west. this
won`t be pure LES as the air mass alone won`t be cold enough to
support it, but the combination of some modest synoptic lift and
reduced stability upwind will lead to an enhancement over the
western tier of counties.
Rather than snow accums, the bigger concern for Friday morning will
likely be a flash freeze of slushy roads and standing water left
over from this week`s warmup, given temperatures falling quickly
from near 40 Thursday evening to the mid to upper 20s by sunrise
Friday. This could significantly impact the Friday morning commute,
especially on the back roads, so residents are encouraged to stay
tuned for further updates.
Friday also looks gusty as the reduced stability from cold advection
aloft allows for more effective momentum transfer. Could see some 25-
30 mph gusts on land (perhaps up to 40 mph along the Lake Superior
shoreline east of Marquette) and gales on the ice-free areas of Lake
Superior, which should have grown quite a bit since last week owing
to this warmup.
Speaking of the lake opening back up... the core of the upper level
trough moves over the Upper Great Lakes Friday night and Saturday
and along with that temps will cool enough to support another round
of LES for the NW wind snowbelts. This round will probably be
steadier and more organized than Friday`s with sfc-850 delta T`s
climbing to about 17 C. It`s a progressive pattern, however, and the
mid-levels start warming and inversion heights begin dropping by
midday Saturday west and late afternoon east, bringing a quick end
to the snow showers after another 1-3 inches Friday night through
Saturday.
High pressure builds in for Sunday and Monday. The next system looks
to be on Tuesday as another northern stream short wave drops
southward across the Great Lakes, but it does not look like anything
significant at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 812 PM EDT WED MAR 13 2019
Warmer, moist air mass flowing n into the area, along with rain at
times, will result in poor conditions at KIWD/KCMX/KSAW through the
forecast period. Downsloping wind initially will allow for MVFR
conditions at KCMX and low MVFR conditions at KIWD. Both of these
terminals will fall to IFR this evening and then probably to LIFR
during the night. At KSAW, upsloping wind through the period should
result in IFR conditions falling to LIFR. Conditions at KCMX/KSAW
may fall below airfield land mins at times late tonight into
Thursday morning. LLWS is also expected tonight into Thu morning.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 437 PM EDT WED MAR 13 2019
Wind gusts up to 20-30kt are possible tonight on Lake Superior, in
particular with the ne winds over far western Lake Superior and the
se winds over the eastern half of the lake. Winds will diminish for
a time on Thu as low pres moves across the area. NW gales of 35-40kt
are then expected in the wake of the low Thu night/Fri. Winds will
diminish over the weekend, becoming light for Sun.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Flood Watch through Friday morning for MIZ001>007-009>014-084-
085.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...RJC
AVIATION...JLB
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Paducah KY
641 PM CDT Wed Mar 13 2019
.UPDATE...
Issued at 639 PM CDT Wed Mar 13 2019
For aviation section only.
&&
.SHORT TERM...(Tonight through Friday night)
Issued at 258 PM CDT Wed Mar 13 2019
Winds were a little slow to get going, but finally have in the
Advisory area. Higher gusts should continue to develop. Will let
the Advisory go as is through 7 p.m. then end.
Band of showers to our west, will be timed in our forecast using the
17z HRRR, 12z ARW, and previous hourly grids in house. Band of
showers and isolated storms will move into southeast MO late today,
and then move west to east across the area tonight. Gusty winds will
likely continue. However, with a convective element in play, no
Advisory extension planned. Some of the convection could mix
increasing 950-850mb winds to the surface, and translate into
pockets of high wind gusts, maybe. Both strong shear and weak
buoyancy may be a hindrance to the modest convection and
overall severe potential.
Will issue a strongly worded Wind Advisory for the entire area
Thursday. Still some question marks as far as a High Wind Warning.
The NAM soundings and HRRR data keeps us just below a warning, with
a slower eastward movement (NAM) of the clouds and precip.
However the new GFS looks like it did 3 days ago or so, reverting
back to a deeper mix layer and warning level gusts (58 mph or
greater). We will let the midnight shift fine tune, and upgrade if
needed. Seems like the area of greatest concern will run north of
a Cape Girardeau MO, to Evansville, IN line, including the I-64
corridor. The mid shift will still have 5-6 hours of lead time on
a potential warning. The Advisory will run from 9 a.m. to 6 p.m.
CDT. Winds will trend down in speed toward sunset.
Through the morning hours Thursday, along and east of the Ohio and
Wabash, convection should regenerate and increase as it moves east.
Severe storms cannot be ruled out, as once again we will have a high
shear environment. Question mark is (again) instability. One
difference with this forecast data vs. recent events is, it shows us
jumping into the lower 70s through the morning, with sfc-5k/ft lapse
rates rising to 8 C/km and above. Damaging winds and a brief tornado
or two cannot be ruled out primarily from southwest IN into west KY.
SEMO and much of southern IL will likely miss out on most of the
main frontal action. By afternoon, lingering convection will be
pushing out of our eastern counties, paving the way for a dry and
cooler Thursday night. We went closer to warmer MOS for highs
Thursday given the strong mixing and return sun for some areas.
Storm total QPF is slightly higher than previously forecast. 1/2 to
1" possible north of Route 13, with 1-1.5" possible south into west
KY and SEMO. However, other than isolated issues, not expecting too
many issues overall.
.LONG TERM...(Saturday through Wednesday)
Issued at 258 PM CDT Wed Mar 13 2019
Surface high pressure will build into the central/southern Plains on
Friday. West to northwest winds will bring colder air into our
region, and we will see unseasonably cool temperatures Friday
through Saturday night. The high will move over the PAH forecast
area Saturday night, and light south winds across our region by
Sunday will result in moderating temperatures. Models show a weak
cold front moving across our region late Sunday. This may produce a
few sprinkles or light showers in our northeast counties Sunday
afternoon, and went with slight chances in these areas.
Another surface high will move from the northern Plains into the
Great Lakes region Sunday night into Monday night, keeping our
region dry with near seasonal temperatures. For Tuesday into
Wednesday, models show and mid/upper level trof and a potential weak
cold front approaching our area. Included some slight chances for
showers across our area Tuesday afternoon, with better chances
Tuesday night into Wednesday. Models are not in sync with timing
yet, so for now kept pops maxed in the chance category. With
&&
.AVIATION...
Issued at 639 PM CDT Wed Mar 13 2019
VFR to occasional MVFR conditions anticipated through tonight, as
a band of showers and isolated storms will move west to east
across the area. Gusty south winds will persist as well. A lull in
the convection is anticipated late tonight, then redevelopment is
expected early Thursday morning mainly over southeast IL, west KY
and southwest IN, moving quickly east through the morning. Some
storms may be strong to severe.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory until 7 PM CDT this evening for ILZ075-080-081-084-
085-088-089-092>094.
Wind Advisory from 9 AM to 6 PM CDT Thursday for ILZ075>078-
080>094.
MO...Wind Advisory until 7 PM CDT this evening for MOZ076-086-087-100-
107>112-114.
Wind Advisory from 9 AM to 6 PM CDT Thursday for MOZ076-086-087-
100-107>112-114.
IN...Wind Advisory from 9 AM to 6 PM CDT Thursday for INZ081-082-
085>088.
KY...Wind Advisory until 7 PM CDT this evening for KYZ001>006.
Wind Advisory from 9 AM to 6 PM CDT Thursday for KYZ001>022.
&&
$$
Update...GM
Area Forecast Discussion
National Weather Service Blacksburg VA
915 PM EDT Wed Mar 13 2019
.SYNOPSIS...
A deep low pressure system in the central United States will
track into southeast Canada, while pushing a strong cold front
through the Mid Atlantic region on Friday. High pressure builds
into the region behind the front by Sunday.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 910 PM EDT Wednesday...
Evening soundings continue to show dry air in the mid/low levels
this evening with mostly a high cloud shield crossing the region
associated with a weak upper vort axis east of the main front to
the west. Still appears guidance too fast to moisten up the low
levels overnight espcly given only weak upslope flow toward
morning. This supported by most short term solutions including
the latest HRRR in having little rainfall across the southwest
until Thursday morning at the earliest so trimmed back pops some
overnight. Otherwise should be mostly cloudy with some breaks
late which should allow low temps to fall off a bit more.
However not nearly as cold as the last couple nights, with lows
mainly in the 40s except 30s in the valleys.
Previous discussion as of 133 PM EDT Wednesday...
High-res models showing more mid/high cloud coverage this afternoon
than the synoptic models. Think the high-res is a little overdone in
the east, so blended the Hi-ResARW with the NAN and CMC to account
for more clouds thru afternoon in the west, with less in the east.
Going to see high pressure work offshore this evening and southerly
flow increases gradually while dewpoints start to creep up from the
20s/30s through the 40s by Thursday afternoon.
For rainfall chances, Nam and High-res models paint more in the NC
mountains late tonight into Thursday while synoptic models are
slower. Will add some sprinkles/isolated showers across the southern
Blue Ridge late tonight.
Southwest flow increase Thursday while deep surface low moves from
the central Plains into the upper midwest. A frontal boundary will
reach the MS River by late afternoon. At this time, expect scattered
showers forming along the Blue Ridge south of Floyd by afternoon
with best coverage across the NC mountains per upslope. Winds will
start to pick up across the higher terrain but strongest low level
jet pushes across the central Appalachians into Ohio, so gusts
should be under 45 mph. A few showers should also spill east ahead
of the front into WV by dusk.
Cloud cover increases and should offset the warm advection somewhat.
We will experience temps above normal Thursday with upper 50s to
lower 60s across the Blue Ridge into the New River and Greenbrier
Valley, to mid to upper 60s across the western slopes of of WV into
far SW VA where southerly flow is going to produce some downslope
warming. Mid to upper 60s will prevail from the Roanoke Valley east
to the piedmont around Lynchburg, with around 70 across the far east
from Farmville VA to Danville to Reidsville.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 300 PM EDT Wednesday...
As a weakening upper level trof moves into our region Friday
night and Saturday, a strong cold front moves through Friday
afternoon. Model and ensemble trends have shown an increasing
trend in instability and shear in advance of this system across
the VA southside and northern Piedmont of NC. Continued to carry
chances of thunderstorm in this region, and there is non-zero
threat for localized severe weather in the far southeast portion
of our area if enough instability can be realized.CIPS
historical analog guidance shows a small probability of severe
wx in the far southeast. Confidence is still low about the
amount of cloud cover forecast which may limit potential
instability.
Temperatures will we well above normal in advance of the front
as 1000-850 mb thicknesses soar.Continued to lean on the warm
side of guidance on Friday, especially in the east.
Behind the front, models are also trending stronger with
pressure rises and low level winds. Using a local program based
on the MET and MAV guidance, peak wind gusts are expected to
remain below advisory criteria but 30-40 MPH gusts are
expected,especially in the mountains Friday night/early
Saturday.
Upslope snow showers will commence in the wake of this front
across the western slopes Friday night into the first half of
Saturday, but forecast soundings show saturation doesn`t occur
in the favorable dendritic grow zone, so snow should be very
light with accumulations less than an inch.
Winds will gradually diminish Saturday with much cooler
temperatures.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM EDT Wednesday..
The deterministic long-range models are in general agreement that an
upper level trof will be in place across the eastern U.S. for most
of the long term period, before transitioning to a zonal or even
southwest flow aloft by Tuesday in advance of a potentially vigorous
northern stream system by mid-week.
There still are some important differences in the models, including
the amplitude of a deepening trof Sunday night into early Monday
with the GFS, and even to a greater extent, the Canadian model,
indicating a deeper and wetter solution versus the 00Z/13 ECMWF and
even the FV3-GFS. Will continue to keep a chance of upslope snow
showers with this feature Sunday night/early Monday. The next chance
of precipitation will arrive toward the end of the long term period.
Temperatures should remain at or below normal for much of the long
term period with the upper trof in place, with some moderation by
Wednesday. GEFS forecasts show 850mb temps 1-2 standard deviations
below average from Sunday-Tuesday.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
As of 800 PM EDT Wednesday...
Expect VFR conditions at TAF sites for the bulk of the valid
period. High clouds will continue to blanket the Appalachians
and central mid Atlantic while return flow around high pressure
to our east starts pushing moisture into the Blue Ridge
overnight. This will result in some upslope clouds along the
Ridge with a few sprinkles/drizzle especially along the southern
Ridge. Some of the ridges along the southern Blue ridge,
especially into northwest North Carolina will be obscured by the
clouds and may have MVFR visibilities in fog early Thursday.
However, TAF sites will remain on the periphery and maintain VFR.
As Thursday wears on, expect cigs to lower to MVFR along and
west of the Blue Ridge.
A low level jet increases from the southwest tonight, so ridges
above 4000 feet may have gusts from 30 to 35 knots. The gusty
conditions will encompass the lower elevations including TAF
sites as well by the afternoon.
Confidence is above average for all forecast elements.
EXTENDED AVIATION DISCUSSION...
A cold front will bring the next chance of rain along with MVFR
ceilings and visibilities late Thursday night into Friday.
After the frontal passage, scattered rain and snow showers could
be possible in the western mountains during Friday night into
Saturday. Conditions will improve to VFR late Saturday into
Sunday as high pressure returns.
&&
.EQUIPMENT...
As of 130 AM EDT Monday...
KFCX Doppler radar in Floyd county will be down for maintenance
March 11-15, 2019.
The WSR-88D Radar operated by NOAA National weather Service in
Blacksburg Virginia will be out of service through
approximately March 15 for the refurbishment of the
transmitter. Although the form, fit and function of the
transmitter will remain the same, old breakers and cables
original to the radar will be replaced with modern fuses and new
cables. This will keep the 20- year- old radar operating
smoothly for another 20 years.
This transmitter update is the second major project of the
NEXRAD Service Life Extension Program, a series of upgrades and
replacements that will keep our nation`s radars viable into the
2030s. NOAA National Weather Service, the United States Air
Force, and the Federal Aviation Administration are investing
$150 million in the seven year program. The first project was
the installation of the new signal processor. The two remaining
projects are the refurbishing of the pedestal and equipment
shelters. The Service Life Extension Program will be completed
in 2022. During the downtime, adjacent radars include KRLX,
KLWX, KGSP, KMRX, KRAX and KAKQ. For direct access to any of
these surrounding radar sites, go to the following web page:
https:/radar.weather.gov/ridge/Conus/northeast_loop.php
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JH/WP
SHORT TERM...PH
LONG TERM...DS/PH
AVIATION...MBS/WP
EQUIPMENT...KK