Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/15/19
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1048 PM EDT Thu Mar 14 2019
.SYNOPSIS...
Mild conditions will prevail for eastern New York and
western New England tonight, as a warm front lifts north of the
region. Showers are expected across most of the region through
in the morning into the early afternoon with breezy conditions
and well above normal temperatures. Then a cold front will bring
back winter type weather with brisk winds and cooler
temperatures with rain and snow showers through the first half
of the weekend.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1048 PM EDT...The mid and upper level ridge axis
continues to slowly shift east of eastern New England this
evening, as a south/southwest flow of mild Mid March air
continues to increase. The low-level stratus is starting to form
and move in across eastern NY and western England. We have seen
it forming first just east of the Hudson River Valley. The 00Z
KALY sounding shows a very strong inversion between 925-875 hPa.
This stable layer will prevent some stronger winds aloft from
mixing to the sfc, as a potent low-level jet continues to funnel
in the low-level moisture. The better isentropic lift with the
warm front does not arrive until after midnight for the
west/northwest portion of forecast area, mainly between midnight
and 3 am, and then begins to expand eastward between 3-6 am
across the Hudson River Valley and towards western New England.
The thunder has diminished upstream over Lake Ontario and
w-cntrl NY, so we did not add isolated thunderstorms at this
time. The showers will be more spotty and scattered from the
Hudson River Valley eastward based on the latest CAMs, such as
the 3-km HRRR and NAMnest. We continued to trend the POPS
slower. The melting snowpack will increase the low-level
moisture in the boundary layer, so patchy fog was added late
tonight into tomorrow morning. It will be a mild night with lows
in the mid and upper 40s in the valleys where the winds stay
up, and mid 30s to lower 40s across the hills/mtns and where the
winds do not decouple.
Previous near term...
Through Friday, there is a narrow window of instability with
respect to the Showalter Index below 0C, yet moisture profiles
remains disjointed. As this seems to be a low confidence event,
we will refrain from mentioning thunder at this time. As for the
showers, 3KM-NAM and HRRR suggest a bifurcation of the mid and
upper level jets. This should in return reduce the overall QPF
which seems to the trend the past several runs. The best shot
for showers appears to be in the morning hours Friday where we
will have the higher PoPs. Within the dry slot by afternoon,
combination of increasing mixing layer potential, southwest flow
and some breaks in the overcast, could result in valley
temperatures climbing into the 60s for valley locations and 50s
elsewhere. This too will continue to increase the snowmelt
across the region.
Cold front per the 18Z HRRR/NAM suggest the Dacks and western
Mohawk Valley around noon, then the Hudson River Valley within a
couple of hours on either side of 18Z then western New England
between 21Z-00Z.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Friday night... Cold frontal passage is well east of the region
as cold advection is underway. H850 temperatures are expected to
plunge back toward -10C across eastern NY by 12Z Saturday. This
will result in residual showers transitioning toward snow
showers overnight. Furthermore, lake effect contributions with
increasing delta t/s and upslope conditions into the higher
terrain and western New England where some increase in showers
are expected. Mixing layer heights and momentum transfer also
increases as wind gusts and blustery conditions increase. Wind
magnitudes of 20-30kts overnight and especially into the
daylight hours on Saturday.
Through Saturday, blustery conditions remain with deep mixing
and continued cold advection for additional snow showers. A few
snow squalls with the lake effect are possible for the western
Mohawk Valley and Dacks where some minor accumulations are
expected. Highs Saturday generally into the lower half of the
40s for the Hudson River Valley and 30s elsewhere.
Saturday night, short wave trough axis is expected to cross the
region. However, nocturnal timing will reduce snow shower
coverage across most of the region. However, lake effect snow is
expected to continue and as low level flow backs around to the
northwest direction, plumes are expected to drift southward and
may impact portions of the Catskills. Overnight lows drop back
into the teens and 20s which will also slow down and stop
snowmelt.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
The mean mid and upper level longwave trough will remain over
southeast Canada, the Great Lakes Region, and the Northeast for the
second half of the weekend into at least the middle of next week
with generally below normal temps. Temps moderate closer to normal
from the mid week into Thursday.
Sunday...Some lake effect snow showers will decrease in the morning
across the western Adirondacks, as high pressure will build in from
the Ohio Valley in the wake of a cold frontal passage. H850 temps
fall to about -10C to -15C in the morning. It will be brisk and
cold with highs in the mid and upper 30s in the valleys with a few
lower 40s in the mid Hudson Valley, and mid 20s to mid 30s over the
hills and mtns.
Sunday night into Monday...The latest GFS/ECMWF/Ensembles have a
fast moving northern stream shortwave moving across the central and
eastern Great lakes Region, and southeast Ontario Sunday night.
Clouds will increase and their could be some isolated to scattered
light snow showers and flurries. The disturbance looks moisture
starved and at this point we carried mainly slight chance pops
across the forecast area initially west of the Hudson River Valley
Sunday night, and then across the entire area on Monday. Any snow
accums look light with a coating to a few tenths of an inch at this
point. Based on the boundary layer temps, some of the snow showers
could change to rain showers in the valleys. The latest 12Z GEFS
continue to show H850 temps -1 to -2 STD DEVs below normal Monday
into Monday night. After lows in the teens to lower/mid 20s across
the region, expect similar max temps compared to Sunday with mid 30s
to lower 40s in the lower elevations, and mid/upper 20s to mid 30s
over the hills and mtns.
Monday night...Cold advection continues in the wake of the short
wave trough and cold front. H850 temps fall to -12C to -16C across
the area (1 to 2 STD DEVs below normal) per the 12Z GFS, and lows
could fall into the single digits over the southern Dacks, and
southern Greens and teens over the rest of the area, except some
lower 20s over the mid Hudson Valley, and southern Litchfield Co.
Tue-Wed...High pressure builds in from the Midwest and lower Great
Lakes Region on Tuesday, and then moves over the area Tue night, and
then shifts east of New England by Wednesday afternoon. Sunny, fair,
cold and dry weather is expected Tue-Tue night with temps running
below normal. However, the return flow from the retreating sfc high
will allow temps to moderate closer to normal by Wed, as lower to
mid 40s will be widespread in the valleys with mid 30s to lower 40s
over the hills and mtns.
Wed night into Thu...Another northern stream shortwave and cold
front may impact the region late in the day on Thu. There are some
timing difference with the Medium Range guidance and Ensembles. For
now, we have gone with a slight chance of rain/snow showers, as
temps ahead of this disturbance continue the trend to normal to
slightly above normal readings.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
A warm front will approach from the south overnight with some
showers. The cold front to the system will move through tomorrow
afternoon into the early evening.
VFR conditions will quickly lower to MVFR cigs with increasing
low-level moisture ahead of a warm front. Cigs will lower from
mid and high level clouds to MVFR stratus of 1.5-2.5 kft AGL
with increasing south to southeast flow between 02Z-06Z/FRI at
KGFL/KALB/KPSF/KPOU. Also, a strong low-level jet with winds of
35-50 kts at 2 kft AGL will impact the TAF sites tonight through
most of tomorrow morning. LLWS groups were continued at
KGFL/PSF/KPOU and added to KALB early this evening and kept
going through the overnight.
Expect widespread low MVFR and even some IFR cigs to impact the
TAF sites with showers between 12Z-16Z. VCSH groups were used
generally between 09Z-12Z/FRI. The best chance for IFR cigs
looks like KPOU/KPSF between 12Z-16Z/FRI. We may have to add
lower cigs at KALB/KGFL later. The question will be how quickly
the cigs increase to VFR levels tomorrow afternoon. We
forecasted a little closer to the NAM sounding and moisture
profiles keeping the cigs at MVFR or low VFR levels in the late
morning into the early/mid afternoon. After 20-21Z for all the
TAF sites we increased cigs to 3.5-4.5 kft AGL with the winds
increasing from the southwest to west.
The wind tonight will be from the south to southeast at 8-13 kts
at KALB/KPSF with some gusts around 20 kts. KGFL/KPOU will see
the sfc winds decouple and be light from the south/southeast at
5 kts or less. The low-level wind shear groups were kept until
15-17Z/FRI at KPOU/KGFL/KPSF...and at Albany until 13Z/FRI. The
winds will increase from the south to southwest at 10-16 kts in
the late morning into the afternoon with some gusts around 25
kts at KALB/KPSF. The winds will shift more to the west at
KGFL/KALB at 9-15 kts with some gusts around 20-25 kts with the
cold frontal passage around 20-21Z/FRI.
Outlook...
Friday Night: Low Operational Impact. Breezy Slight Chance of SHRA.
Saturday: Moderate Operational Impact. Windy. NO SIG WX.
Saturday Night: Low Operational Impact. Breezy. 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.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Outside some locations in the mid Hudson Valley, we have snow
on the ground with deep snowpack across the higher terrain.
Temperatures will be mild through Friday with a return to below
normal readings over the weekend into early next week. Scattered
to numerous showers are expected Friday, mainly in the morning.
&&
.HYDROLOGY...
We will have a period of mild temperatures through Friday with
temperatures well above normal which will lead to snowmelt.
There is uncertainty to how much melt and runoff there will be.
Scattered to numerous showers are expected Friday, mainly in the
morning, however QPF amounts are expected to be light generally
less than a quarter of an inch. Higher amounts of a quarter of
an inch to possibly a half inch are expected across the western
Adirondacks.
The combination of runoff from snow melt and rainfall will lead to
rises on rivers and streams, but it`s not expected to be enough to
cause rivers to reach or exceed flood stage per latest guidance
and coordination from NERFC. There is the possibility flow
could be great enough to cause to ice to move/break up which
could lead to localized ice jam flooding. Confidence is not high
enough at this time to issue a flood watch.
Colder air will be ushered in Friday night with temperatures
expected to drop into the mid 20s to upper 30s slowing and even
stopping the melt. As we look ahead into early next week, below
normal temperatures will limit any snowmelt with highs only in the
upper 20s to lower 40s.
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...BGM/Wasula
NEAR TERM...BGM/Wasula
SHORT TERM...BGM
LONG TERM...Wasula
AVIATION...Wasula
FIRE WEATHER...IAA/BGM
HYDROLOGY...IAA/BGM
AREA FORECAST DISCUSSION
National Weather Service Binghamton NY
959 PM EDT Thu Mar 14 2019
.SYNOPSIS...
A cold front will come through the region on Friday bringing
with it some showers. This will be followed by another cold
frontal passage this weekend with some scattered rain and snow
showers.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
With the evening updates, Some minor adjustments were made on
the timing of the showers coming in overnight. Still on track
for the showers to become more likely after midnight from west
to east.
A strong low pressure system will continue to track through the
Great Lakes and bring a cold front through the area on Friday.
CLouds will continue to increase ahead of the cold front with
increasing southerly winds. The clouds and winds should keep
temperatures up in the upper 40`s and low 50`s tonight. A
fairly good model agreement is in place between the Hi-res NAM
and HRRR bringing in showers just after midnight in the Finger
Lakes then further eastward as the overnight goes on. Rainfall
looks rather light from this system given the main low pressure
system will be well northwest of our region.
Modeling however has different outcomes with regards to
clearing behind the front. The GFS is much quicker clearing the
system than the NAM. Quicker clearing would allow for more
mixing and the potential for stronger westerly wind gusts
throughout the day. This forecast is between the two extremes at
this point with morning clearing/ showers ending and also
showing the potential for some 20 mph wind gusts.
High temperatures once again should get well into the 50`s and
perhaps low 60`s before the cold frontal passage. After the cold
front passes through temperatures should fall off quick into
the 30`s by Saturday morning. Scattered rain and snow showers
with the aid of northwesterly flow and moisture off the Great
Lakes will be present as well Friday night.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
2 pm update...
A fairly quiet period with below normal temperatures and a few
showers. Total snow accumulations will be under 2 inches and
mostly across the higher terrain of CNY Saturday night. For
the entire period under an upper level trough.
For Saturday and Saturday night the area is under cold air
advection and northwest low level flow. A short wave goes
through in the afternoon providing some lift. Surface
temperatures are warm enough for a mix of rain and snow in the
afternoon. High temperatures from the mid 30s to lower 40s.
Saturday night and Sunday the forcing wanes. Moisture levels
lower. The low level flow shifts from 280 to 300. This keeps
the best shower coverage in the Syracuse area. On Saturday
chances for showers best from the Finger Lakes to the western
Mohawk Valley and Tug. Saturday night the showers are mostly in
the eastern Finger Lakes to the upper Susquehanna Region. Sunday
morning just some flurries before ending. Saturday night low
temperatures around 20. This is about 5 degrees below normal.
Sunday highs in the 30s which is about 10 degrees below normal.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Another shortwave starting to track through the area Sunday night
will spread snow showers throughout the rest of the area Sunday
night through Monday, especially across NE PA and the Southern Tier.
High pressure begins to build in, though, and will help to dry
things out Monday evening with sunny and dry conditions through
Tuesday.
Models continue to bring in another system Wednesday
through Thursday, with the possibility of rain/snow showers starting
as early as Wednesday afternoon - though there continues to be quite
a bit of disagreement on the timing with this next system.
Therefore, will keep rain/snow chances in Wednesday through Thursday
afternoon, finally wrapping up Thursday evening with the passing
cold front.
As for temperatures, we`re looking to stay more or less seasonal
through the long term. Low temperatures start generally in the teens
and 20s Monday through Thursday, with highs in the 30s to mid 40s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR this evening then ceilings forming and likely becoming MVFR
with some showers overnight. The MVFR ceilings are more
conditional and uncertain at KSYR, KELM and KITH. Showers look
to start around 06Z from SYR to KELM and closer to 8Z or so
around KBGM. Showers will end from west to east from about
10-15Z Friday. Southeast winds overnight around 15 knots will
become more westerly on Friday. LLWS is expected at all TAF
sites till around 12-15Z Friday.
Outlook...
Friday night through Saturday night...Possible restrictions
with rain changing to snow showers; mainly NY terminals.
Sunday...Becoming VFR.
Sunday night and Monday...Possible restrictions in snow showers.
Tuesday...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MWG
NEAR TERM...MWG
SHORT TERM...TAC
LONG TERM...HLC
AVIATION...MWG
Area Forecast Discussion
National Weather Service Columbia SC
916 PM EDT Thu Mar 14 2019
.SYNOPSIS...
Offshore high pressure will direct a southerly flow into the
forecast area overnight. An approaching cold front will move
through the area Friday afternoon and evening. It will be breezy
ahead of the front Friday. The front will bring a chance of
showers and thunderstorms. It will be dry and cooler behind the
front for Saturday and Sunday.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Moisture should remain shallow overnight because of the
lingering effects of upper ridging. The main frontal forcing
will remain west of the area. The HRRR keeps showers west of the
area through sunrise. It will be a mild night as low-level warm
advection on southerly winds and mostly cloudy skies will keep
minimum temps 15+ degrees above normal. Many places will not
drop below 60. Mixing should help prevent fog.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Friday and Friday Night...The strong winter storm currently
impacting the middle of the country will send a cold front
through the region on Friday. The day should start out mostly
dry and compressional heating ahead of the front will allow the
area to warm into the mid 70s in the west and low 80s east.
Breezy southwest winds can also be expected ahead of the front.
The front is expected to cross the region during the afternoon
and evening with showers and thunderstorms, but convection
could begin developing late morning across the northwest CWA. Although
the area is not currently outlooked by the Storm Prediction
Center, there is the potential for a few storms to become strong
or even severe given good vertical shear profiles and the
presence of a 45-50kt 850mb jet. The limiting factor could be
reduced instability due to considerable cloud cover ahead of the
front.
The front will move through quickly and any lingering showers
and isolated thunderstorms will be limited to mainly the eastern
Midlands and lower CSRA Friday evening, then will shift east
out of the area as drier air filters in behind the front. Low
temperatures will be in the mid 40s to lower 50s.
Saturday and Saturday Night...Surface high pressure will build
over the area, with fairly light northerly winds and a dry
airmass in place. Temperatures will be considerably cooler
behind the front, with highs in the lower to mid 60s and
nighttime lows in the upper 30s to lower 40s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
The long term period will be mostly cool and dry. An upper
level trough that will prevail over the eastern U.S., with the
passage of several shortwaves causing the upper trough to dig
deeper at times, especially late Monday/early Tuesday then again
on Wednesday night into Thursday. Moisture will be limited, so
kept the forecast dry for now, but cannot rule out a few showers
with the stronger shortwaves. Temperatures will generally be in
the 60s during the day and the mid 30s to low 40s at night.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
Expect mainly VFR conditions through 10Z. MVFR conditions
possible Friday.
A warm and moist southerly flow will hold across the region
overnight between high pressure off the coast and an
approaching cold front to our west. Models indicated VFR
conditions through 10Z with sct/bkn stratocumulus clouds above
3000 feet agl. Have also included LLWS as a 35-40 knot low
level jet sets up across the area 05Z-15Z. After 15Z southwest
winds increase 10-15 knots with gusts around 20 knots.
Forecast soundings suggest the potential for MVFR cigs after
10Z as low level moisture increases just ahead of the cold
front. Could also see scattered showers develop by late morning,
but the best chance for convection will be in the 17Z-22Z time-
frame. Isolated to scattered thunderstorms possible ahead of
the front. The front will be east of the TAF sites around the
end of the period with winds veering west and precip moving
east.
EXTENDED AVIATION OUTLOOK...No significant restrictions to
aviation expected through Tuesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service State College PA
1151 PM EDT Thu Mar 14 2019
.SYNOPSIS...
A potent storm will track up through the central Great Lakes
tonight, dragging a cold front across central Pennsylvania on
Friday. Cooler and windy conditions will follow for Friday
afternoon and Saturday. Diminishing wind and dry conditions will
occur on Sunday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Radar loop at 0130Z shows a solid line of showers entering
northwest Pa along axis of low level jet. The cold front is
still back in western Ohio and is progged to push into the
western part of the forecast area late tonight.
Linear extrapolation of radar returns and latest HRRR support
near 100 pct POPS late this evening across Warren/Mckean
counties. Parent shortwave will be weakening overnight and
lifting northeast, rather than east, so expect band of frontal
showers to dwindle late tonight as it enters the central
mountains.
Models erode stability in the increasingly moist airmass ahead
of the approaching front, so a rumble of thunder would not be a
big surprise as convection pushes into the forecast area.
Increasing southerly flow and cloudcover ahead of the cold front will
make for a very mild overnight. Lows generally in the 50s will
be some 20-25 deg warmer than they should be for the last week
of winter.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
The slowing cold front will move through the eastern part of the
forecast area during the late morning and afternoon, accompanied
by scattered showers and even a possible rumble of thunder. Models still
showing a bit of pre-frontal cape through early afternoon, but
weakening forcing in vicinity of slowing front. The front and
associated threat of showers may not clear southern York/Lancaster
counties until around 21Z.
Surface ridging and much drier air behind the front is expected
to result in clearing skies spreading southeast across the
region during the late morning and afternoon hours. Model
soundings indicate mixing to 850mb behind the front, supporting
highs well into the 60s over the central part of the forecast
area and possibly into the low 70s over the southeast. After a
mild start, readings across the northwest mountains are likely
to fall through the 40s during the afternoon.
Vertical mixing depth up to 5000ft will help support some wind
gusts in the 25-35 mph range all day across the western counties
and spreading into the southeast counties by afternoon.
Increasing clouds and the chance of showers will spread
into the northwest mountains during the afternoon hours in
association with approaching upper trough over the Grt Lks.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
*Noticeably cooler and chilly weekend with lake effect snow
*Dry wx pattern with near to below avg temps Mon-Wed
Not a lot of change to this portion of the fcst package.
Still looks like a dry slot later Friday afternoon into the
early evening, before secondary push of colder air works in
late Friday night into Saturday.
I did adjust the weather grids some, but mainly looking at small
amts of snow.
Went with mainly dry conditions on Sunday.
For Monday and again later Wednesday into Thursday, some small
chance of a snow and rain showers.
Overall, a welcome change to a drier pattern.
More detail below.
A fresh wave of cooler, drier air will arrive by the weekend.
24hr maxT changes Fri to Sat will be a rather noticeable -20 to
-30 degrees (colder).
A gusty west northwest wind 25-35mph will add to the chill with
lake effect snow showers bringing a coating to some parts of
the Alleghenies Fri night into Saturday.
Despite some variability, the overall wx pattern should feature
mainly dry conditions with near to below avg temps Mon-Wed.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
A potent storm will track west of the state Friday. This will
bring showers and lowering conditions into the NW later this
evening, spreading eastward overnight and early Friday ahead and
along the cold front. A thunderstorm will be possible as the
cold front crosses the flying area late tonight and early
Friday.
Another concern will be LLWS out ahead of this approaching
system as strong winds just off the deck begin to develop over
the flying area.
The showers will bring occasional MVFR/isolated IFR conditions
for a few hours from the NW to the SE between about 09-15Z.
After frontal passage Friday morning expect improving
conditions. A gusty WSW wind will develop by Friday afternoon,
in the 25-30kt range at most terminals.
Cooler but mainly dry conditions will follow for the weekend
into next week, with restrictions likely over the NW mountains.
Outlook...
Sat...Breezy. Restrictions with scattered rain/snow showers NW.
No sig wx elsewhere.
Sun-Tue...No sig weather.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald/La Corte
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/La Corte
LONG TERM...Lambert/Martin/Steinbugl
AVIATION...La Corte/Gartner
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
800 PM EDT Thu Mar 14 2019
.AVIATION...
Corridor of 1000-500mb height falls and initial cold advection in
the 1.5 to 4.5 kft agl layer is currently supporting a severe
thunderstorm event over Southeast Michigan. Extreme shear setup with
modest late day instability recovery led to embedded supercell
thunderstorms that resulted in reported tornado activity. Warm
advection and moisture transport is strong enough to maintain a
potential for severe thunderstorms with the primary threat of
straight line winds to the east of the current line/through all of
the cwa. Latest extrapolation supports the thunderstorms ending at
all terminals by 02Z.
The focus will then shift late this evening to the potential for
strong west flow in the wake of the cold front. Cold advection with
steep low level lapse rates will support winds to 40 knots. Models
support a deep mixed layer to 4.0 kft agl in the presence of strong,
deep environmental wind profile. Low level wrap around moisture and
diurnal minimum suggests weakening winds at/around 09Z tonight.
Secondary shortwave energy lifting northward under jet impulse aloft
will support an area of light rain or drizzle beginning around 16Z.
.DTW THRESHOLD PROBABILITIES...
* High for rain as precipitation type.
* High for thunderstorms early evening.
* High for ceiling 5000 ft or less late overnight through Friday
morning.
&&
.PREV DISCUSSION...
Issued at 327 PM EDT Thu Mar 14 2019
DISCUSSION...
Not much has changed from this mornings thoughts/updated afd.
Southeast Michigan remains devoid of surface based instability as of
3 PM (per SPC mesoscale analysis) as elevated widespread showers
have tracked through and kept temps below 60 degrees (thus far).
Subsequently, gradient winds have been subdued with the surface based
inversion persisting.
Main mid level circulation/cold pool (-23 C at 500 MB) tracking into
far southern Wisconsin late today, with cold front moving through
southeast Michigan 23-2Z, and thus still a short window to recover
before sunset, as latest RAP still indicating MLCAPES reaching
around 500 J/kg which could be just enough to generate low topped
supercells with the strong low level wind fields in place. Still,
bulk of the hires solutions are fairly muted with the activity
moving through southeast Michigan.
Cold advection then kicks in late this evening, and continuing
through the day tomorrow, with the increasing boundary layer depths
offset by the decreasing wind fields should keep gusts mostly aob 40
MPH, but still have 50 knots of flow at 850 MB at 9z Friday. Initial
post front surge late this evening with about 20 MB rise/fall
pressure couplet, so not out of the question to get brief wind pop
to 45 mph but not planning on issuing an advisory.
With trough axis/height falls swinging through Central Great Lakes
Friday evening and 850 MB temps lowering to around -10 C, numerous
to widespread rain/snow showers appear likely as low level lapse
rates ramp up during the day and surface based capes reach around 50
J/kg by early evening. Slow loss of daytime instability will allow
activity to dwindle Friday night, despite some continued cold
advection (negative lower teens at 850 MB), but not enough to get
much Lake Michigan activity going with inversion heights under 5
kft. However, cold advection will likely be able to sustain brisk
northwest winds through the night.
Re-enforcing shot of cold air, secondary trough axis to swing
through on Saturday. This will assure cold and cloudy conditions
during the day, as both GFS and NAM indicating saturation at 850 MB.
Cape/cloud depths look shallow in the 4-6 kft foot layer per NAM
soundings, but do reside in the DGZ. Will at least introduce a
chance of flurries to account for some activity as highs hold in the
30s.
For the majority of the extended forecast period going into next
week, conditions look to remain dry with only a couple of chances
for precipitation. High pressure will continue to influence the
region for much of the period, with the exception for some scattered
rain/snow showers Sunday afternoon. The only other period a this
time that is looking at chances for rain/snow is on Wednesday. High
temperatures will continue to slowly warm through the 40s towards
the end of next week with lows still below freezing at night.
MARINE...
A strong low pressure system continues moving through the Midwest
and northern Great Lakes tonight while drawing very mild air
northward across the central Great Lakes. This relatively warm air
passing over the cold, mostly icy lakes, results in strong stability
and limits wind gust potential to 25 to 30 knot range until passage
of the associated cold front. A few gusts near gales are possible
post front in the southwest flow tonight across all marine areas and
then again in northwest flow later Friday and Friday night over the
north third of Lake Huron. Colder air gradually takes hold during
this time and leads to deeper mixing in stronger pressure gradient.
Similar conditions persist into Saturday over northern Lake Huron
before high pressure builds into the region. Weak high pressure
holds through Sunday as equally weak low pressure system move
through northern Ontario and through the Ohio valley.
HYDROLOGY...
A Flood Watch remains in effect for the Tri Cities area through
Friday morning for potential flooding due to a combination of heavy
rain and melting snow/ice. The runoff of rainfall and melting snow
will bring rises in area streams and rivers resulting in potential
flooding of prone areas. This will be especially true within the
Tittabawassee River basin over central Lower Michigan where the snow
pack contains the moist liquid. So, despite the relatively low
rainfall totals, the Tittabawassee (and in turn Saginaw) Rivers are
forecast to approach flood stage this weekend. Some ice breakup will
likely occur within other area rivers as well due to the warmer
weather and rainfall. This will lead to an increased chance of ice
blockages and flooding in prone areas.
The potential for flooding remains driven by a strong storm system
moving across the Midwest and northern Great Lakes that is drawing
very mild air into the region. This supports showers and scattered
to numerous thunderstorms through the evening followed by passage of
an associated cold front. Overall rainfall accumulations around a
half inch are expected before the system exits the region tonight.
Rainy and cooler conditions continue through Friday but with minimal
additional rainfall.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Flood Watch through Friday morning for MIZ047-048-053.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....CB
DISCUSSION...SF/SP
MARINE.......BT
HYDROLOGY....BT
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
937 PM EDT Thu Mar 14 2019
.SYNOPSIS...
Showers and thunderstorms return to the area through the end of the
work week as a cold front moves through the area. Dry conditions
return this weekend as high pressure builds in, and cooler
temperatures are expected next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 930 PM EDT Thursday: No major changes to the forecast with the
late evening update. Convection across GA is bringing its own
environment slowly east, but modifying as it does so, with the RAP
not wanting to develop any surface-based instability in our area
ahead of the front...though some minimal instability may move in
after 06z with the front itself. HRRR still hinting at some slightly
more intense cells that may be SPS-worthy overnight.
Otherwise, expect a very mild night, with min temps in the 50s
mountains to lower 60s piedmont given abundant cloudiness east of
the approaching front. The surface cold front should move through
the western mountains around daybreak, cross the foothills through
the late morning hours, and then move east of I-77 during the
afternoon hours. Shear appears rather unidirectional across the
region through the period of the pre-frontal convection, but surface
to 3 km bulk shear does rise to near 40 kt east of the mountains.
Surface-based CAPE values should be 600 J/kg or less as the shower
band traverses the region, with instability bubbling up mainly just
east of the area Friday afternoon. This is in line with the latest
SPC Day 2 Marginal outlook across central/eastern NC. However, lapse
rates will gradually steepen up to greater than 6 deg C/km tonight
through Friday along and ahead of the frontal zone, so isolated to
scattered thunder will be warranted throughout. Expect a window of
heavier rainfall in the southwest mountains tonight/Friday morning,
but this should not be excessive given current stream/river levels.
Isolated showers could persist near the TN border late in the day
Friday in moist-low level post-fropa NW flow.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 230 PM EDT Thursday: A broad upper trough will set up over the
eastern CONUS for the upcoming weekend, maintaining a jet streak
over the Tennessee Valley to the Mid-Atlantic. This will keep the
forecast area within the cirrus/altostratus side of the jet, so a
fair amount of high clouds will continue to stream over the area
thru the period. But overall, things dry out by late Friday evening
and remain dry thru Sunday, as a modest 1025-1030 mb area of high
pressure builds in from the west. Temps will be seasonable, slightly
above normal Friday night and Saturday, then slightly below normal
Saturday night and Sunday, thanks to a persistent NWLY CAA flow atop
the region.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
As of 100 PM Thu: A secondary cold front looks to push southward thru
the region early Monday, with dry and cold high pressure expanding south
behind it. This will keep temps several degrees below normal thru the
middle part of next week. Within the broad-scale upper trough over the
eastern CONUS, an embedded shortwave will swing across the CWFA Monday
or Monday night. The GFS remains the most amplified with this feature,
and is alone among the major models in depicting precip accompanying it.
Thus we will continue to advertise a dry fcst at that time. There is
better agreement on a better defined wave advecting across the
Appalachians late Wed into Thu, and this warrants some PoPs for the
mountains and some of the foothills. As temps cool to near freezing in
those areas Wednesday night, it is possible for rain to change to snow.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Low VFR cigs continue this evening, but as
the moisture increases ahead of the approaching front, cigs will
drop to MVFR and then at least some period of IFR likely on Friday
morning. Overnight showers will remain mainly in the mountains,
spreading east early tomorrow. Some instability will develop as
well, and have continued previous trend of VCTS or PROB30 TSRA at
most sites except KCLT, where chances are a little too low to
include in the TAF at this time. Winds will be SSW to SW and
occasionally gusty with the strong gradient ahead of the front. Wind
shift timing to NW just before 00z at KAVL so introduced that, and
should be shortly thereafter at other sites so only included the
wind shift at KCLT.
Outlook: Dry weather will develop behind the front over the weekend
and likely persist into early next week.
Confidence Table...
01-07Z 07-13Z 13-19Z 19-00Z
KCLT High 100% High 92% High 92% High 95%
KGSP High 100% High 90% High 81% High 100%
KAVL High 84% High 96% Med 77% High 100%
KHKY High 98% High 91% Med 68% High 95%
KGMU High 98% High 89% High 83% High 100%
KAND High 100% High 84% High 94% High 92%
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...Carroll
NEAR TERM...HG/TDP
SHORT TERM...Wimberley
LONG TERM...ARK
AVIATION...TDP
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1015 PM EDT Thu Mar 14 2019
.UPDATE...
Issued at 1015 PM EDT THU MAR 14 2019
With winds decreasing will expire or cancel all wind advisories
for our area shortly before 11 PM. A small severe threat will
continue for the next couple of hours though. Strongest storms
continue to occur just to the northwest of the forecast area,
where warnings are in effect for parts of northern KY. Some of the
small storms in the southern part of our forecast area have shown
some rotation, and a storm near London produced some pea size
hail around 10 PM.
UPDATE Issued at 809 PM EDT THU MAR 14 2019
While the severe threat has diminished in our area considerably we
are still not completely out of the woods, and an isolated severe
wind gust remains possible until midnight or so. An axis of
instability with MUCAPE in excess of 500 j/kg still exists across
central KY and storms continue to develop on the southern end of
a band of broken storms that extends northeast into OH. In fact
a severe thunderstorm warning was issued for parts of Shelby and
Franklin counties at 752 EDT. It does appear the axis of
instability will decrease as it shifts east tonight. The HRRR has
been persistent in trying to evolve the broken cells to our
northwest into a narrow band of showers and thunderstorms that
will move across our area between 03Z and 08Z, with the line
weakening as it moves east. The best chance of any severe storms
would be in the western part of our area before midnight. Made
some minor adjustments to rain chances this evening, but based on
the consistent HRRR have continued with high probabilities as a
line of showers and storms is forecast to move across the area.
Will continue with the wind advisories as they now exist, but
wind gusts outside of storms and showers should gradually
diminish.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 434 PM EDT THU MAR 14 2019
Storm system bearing down on our area. Storms to the west will be
moving into an environment less conducive for maintaining strength
and severity of storms that we have seen to our west through the
day. Just the same, marginal conditions do not entirely count out
the possibility...as seems to happen quite often in our area. We
are currently in discussions with SPC to determine what type of
watch if any should be issued for our area. Determination will
likely be made soon.
Will continue with the winds advisory as is. Still seeing some
gusts even though there has been a bit of a drop off. Cooler air
coming in behind this front will bring our temps back down to
normal levels. Rainfall across the area will be a bit limited as
well with such a progressive system. In general looking for
around a half inch or less, but locally higher amounts will be
possible with any thunderstorms.
.LONG TERM...(Saturday through Thursday)
Issued at 434 PM EDT THU MAR 14 2019
The period will begin with high pressure sinking southward out of
the Midwest and west to northwest flow bringing in a cooler
airmass into the Ohio Valley. This will lead to generally below
normal temperatures across the region through The weekend into
early next week. For the most part we are looking at dry weather
through early next week, but an upper level wave and surface cold
front could bring a slight chance of showers by Sunday night.
After this dry weather continues until Wednesday afternoon into
Thursday when another storm system arrives. Overall model
agreement is not bad, but the ECMWF is the driest model at this
point.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 741 PM EDT THU MAR 14 2019
Strong southerly winds ahead of an approaching cold front will
continue this evening, with occasional gusts of around 35 knots.
Low level non-convective wind shear will also continue to affect
all TAF sites through at least 03Z and likely later at most TAF
sites. While a narrow line of thunderstorms may move across the
area between 02Z and 06Z this is still not certain even at this
time. Scattered showers will occur but conditions should only
temporarily drop from VFR to MVFR. The cold front will pass
through the area tonight and winds on Friday will remain gusty but
be out of the west or southwest. Wind gusts on Friday will be 20
to 25 knots.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 11 PM EDT this evening for KYZ044-050>052-
058>060-068-069-079-080-083>085.
Wind Advisory until 1 AM EDT Friday for KYZ086>088-104-106>120.
&&
$$
UPDATE...SBH
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...SBH
Area Forecast Discussion...CORRECTED
National Weather Service Lake Charles LA
1047 PM CDT Thu Mar 14 2019
.DISCUSSION...
NE to SW oriented frontal boundary lies between New Iberia and
Patterson as of this writing, with drier and cooler air continuing
to filter into the region from the NW. Strong SFC high is
forecast to continue building into N Texas through the overnight
hours, kicking the surface boundary east of the area in the next
few hours. Tightening pressure gradient along with CAA will result
in increasing N winds and building seas over the coastal waters,
and the inherited marine hazards were left largely as is.
Increasing ascent is also progged over the SE half or so of the
forecast area, and there has already been a recent uptick in light
radar returns as this process gets underway. While a stray
lightning strike is not out of the question, anticipate mostly
areas of rain and/or showers. PoP/Wx grids have been updated
accordingly. Rest of the forecast is on track, though did freshen
up hourly grids to nudge them a little closer to Obs.
13
&&
.PREV DISCUSSION... /issued 635 PM CDT Thu Mar 14 2019/
AVIATION...Cold front is now between LFT and ARA and extends
southwest into the gulf waters. Radar showing nothing more than a
few light showers over lower Acadiana and these will be exiting
shortly as boundary advances further southeast. Carrying a dry
forecast throughout TAFs at all terminals. VFR expected with just
some mid-level cloudiness holding over the region.
PREV DISCUSSION... /issued 1220 PM CDT Thu Mar 14 2019/
AVIATION...A cold front will continue to move east across the
region through the afternoon. The boundary will pass KLFT and KARA
through the next few hours. Behind the boundary ceilings will
improve with VFR conditions expected for the rest of the period.
Winds will become NW at all terminals this afternoon, but veer
more northerly during the night.
PREV DISCUSSION... /issued 1040 AM CDT Thu Mar 14 2019/
UPDATE...
Cold front is slipping through the region with temps in the lakes
region of southeast texas dropping into the upper 60s while srn
Louisiana remains in the 70s. The front is forecast through south
central Louisiana this afternoon. This will end the threat for
additional fog issues. Winds to pickup tonight as a secondary
stronger cold surge drops down into the coastal waters with winds
picking up and seas building. Current zones are fine.
PREV DISCUSSION... /issued 818 AM CDT Thu Mar 14 2019/
UPDATE...Dense sea fog has developed this morning over nearshore
gulf and coastal lakes. A prefrontal trough is also moving through
which is mixing out fog over SE TX and Sabine Lake. Conditions are
expected to improve over Calcasieu Lake through the next few
hours as the trough approaches. An advisory for sea fog is in
effect through 16Z.
PREV DISCUSSION... /issued 630 AM CDT Thu Mar 14 2019/
DISCUSSION...
For the 14/12Z TAF Issuance.
AVIATION...
A cold front from northwest Louisiana down to east central Texas
will continue to move steadily to the east and across the forecast
area this morning into early afternoon hours. Breezy and gusty
south winds with IFR/MVFR ceilings will occur ahead of the front. A
weakening line of showers and a few thunderstorms will occur right
along the frontal system, with possibly some brief visibility
restrictions and ceilings continuing at MVFR levels. Looks like
KAEX will be the only terminal that has a shot of some isolated
lightning with this line of showers so will have VCTS for them
ahead and along frontal passage. Behind the front, northwest winds
will occur and drier air will gradually filter in to end shower
activity and raise ceilings to VFR levels.
Rua
PREV DISCUSSION... /issued 357 AM CDT Thu Mar 14 2019/
DISCUSSION...
Short Term [Today through Saturday]
This morning`s surface analysis indicates a surface cold front
extends from east of Dallas south-southwestward to just west of
San Antonio. This cold front has produced a line of thunderstorms
that has been expanding over the past few hours. Some of these
thunderstorms have been severe and produced damaging winds across
portions of east Texas.
Thus far, the HRRR has had a relatively good handle on the
evolution of this line of convection over the past several hours.
It depicts the line of thunderstorms approaching the northwestern
portions of the CWA around 6 AM and gradually becoming less
consolidated as it moves southeastward through the rest of the
morning hours. Therefore, northwest portions of the CWA were left
out of Severe Thunderstorm Watch 22 which is in effect until 7 AM
CDT for adjacent portions of the Houston and Shreveport CWAs.
However, a few strong thunderstorms will still be possible this
morning with gusty winds and small hail being the main threats.
The line of thunderstorms will continue to be monitored to
determine if the threat of severe thunderstorms will become more
widespread later this morning.
The cold front is expected to push offshore by late this
afternoon. This will bring an end to precipitation chances inland
portions of the CWA. Over running precipitation is expected to
linger over the coastal waters and along on Friday and Saturday
before high pressure builds southward. Cold air advection
associated with the cold front and cloud cover from over running
moisture will result in cool temperatures on Friday and Saturday
with highs only in the upper 50s/low 60s.
Long Term [Sunday through Wednesday]
During the long term period, a longwave trough is forecast to
develop over the central and eastern portions of the CONUS with
the trough axis centered roughly along the East Coast. Later in
the forecast there will be some uncertainty as model guidance
depict a variety of evolutions for individual shortwaves that will
be rotating through the longwave trough. However, the trough axis
being predominately centered east of the region should result in
a prolonged period of drier conditions. Temperatures will start
out below normal and gradually return to near normal by the middle
of next week.
MARINE...
A cold front will push southeastward through the coastal water
today, accompanied by showers and thunderstorms. In the wake of
the front, northerly winds of 20 to 30 knots will develop this
evening and continue into Saturday. In addition to the strong
winds, seas will build and Small Craft Advisories will be needed
for the majority of the coastal waters. Winds and seas are
expected to gradually subside during the second part of the
weekend as high pressure builds into the area.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 76 46 62 41 / 60 10 0 0
LCH 82 51 61 47 / 60 20 20 20
LFT 79 53 60 47 / 60 50 30 30
BPT 81 51 61 47 / 60 10 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until 7 PM CDT Friday for GMZ450-452-455-
470-472-475.
Small Craft Exercise Caution through Friday evening for GMZ430-
432-435.
&&
$$
Corrected minor typo.
Area Forecast Discussion
National Weather Service Blacksburg VA
852 PM EDT Thu Mar 14 2019
.SYNOPSIS...
A deep low pressure system will move northeast into southeast
Canada by Friday morning, while pushing a cold front across the
Mid Atlantic region Friday. High pressure builds in behind the
front for Saturday and Sunday. A weak front then crosses the
area Sunday night.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 845 PM EDT Thursday...
Seeing a batch of light showers crossing into the far west this
evening basically between bands of deeper convection to the
southwest along the cold front, and to the northwest closer to
the frontal triple point. Latest evening soundings still show
some mid level dry air hanging on so eastward extent of the
current showers may be limited until the corridor of better lift
near the front arrives overnight into early Friday. Latest HRRR
also suggests that the more organized showers wont arrive until
after midnight and be limited by lack of much instability. Thus
increased pops a bit sooner along/west of the I-77 corridor for
low QPF amounts, while removing any thunder mention until late
along the western slopes when have pops bouncing back to high
chance/likelys west. Combination of the jet aloft/mixing and
clouds likely to keep temps quite mild in spots overnight with
some spots staying near or above 60. Expect showers to allow for
a little better cooling mountains where nudged lows down closer
to 50.
Previous discussion as of 250 PM EDT Thursday...
Plume of mid/high level moisture continues to streak northeast over
the central Appalachians this afternoon, with strong southwest flow
aloft. Lower clouds affecting the NC mountains into the southern
Blue Ridge of VA will hang tough into this evening, before mixing
increases ahead of a cold front. This front is spawning severe
weather from Indiana/western Ohio south through MS/AL this
afternoon. As the main low shifts further north across the Great
Lakes into Canada the frontal line of showers/storms will stretch
out more and become less organized as it moves toward our county
warning area tonight. Still should be enough to warrant high chance
to likely pops. Given the line is arriving at night and late, will
see little threat of thunder, but cannot rule out some isolated
rumbles across SE WV.
Friday will see the scattered to numerous showers head into the New
River Valley by mid morning and reach the piedmont by midday to
early afternoon. Forecast reflects best forcing across the southern
tier of the area in NC and have pops more in the likely to cat range
with lower chances over the north, albeit still good chances.
SPC has a marginal risk highlighted for severe weather along and
east of a Amelia Court House to Staunton River State Park to
Roxboro, NC line. As such will not mention severe threat in the
hazardous weather outlook. Thinking early day coverage of showers
and clouds will limit severe potential, but will have some isolated
thunder in the east during the afternoon.
As for temps expect milder temps tonight as clouds and warm
advection increases, such that lows will be warmer than our normal
highs for this time of year. Not out of the question to see some
record warm lows tied or broken. See the records in the climate
section below for March 15th.
Warm Friday will be experience but less sunshine. Cold advection
should bring falling temps in the afternoon across the mountains but
temps will still be mild as we head toward dusk. High temps will
range form the lower 60s in the mountains, to around 70 in the
piedmont.
Forecast confidence is high for the temps and winds, but
moderate on coverage of rain as some high-res models are showing
a little less coverage per stretching/weakening of the front.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 305 PM EDT Thursday...
The late week into the weekend period on the whole is rather
quiet/uneventful, aside from a period of gusty northwest winds and a
brief period of light upslope snow showers with little accumulation
on grassy surfaces Friday night into Saturday. Another light precip
event possible late Sunday into Sunday night but not appearing too
significant.
Highlights include:
* Gusty northwest winds, potentially to Advisory levels along
the Blue Ridge Friday night into early Saturday.
* Brief period of snow showers in the western mountains overnight
Friday into early Saturday, and potentially again Sunday night.
Neither of which looks substantial/impactful.
* Return to more seasonal temperatures with drying/lowering relative
humidities.
Broad mean longwave trough/cyclonic flow aloft will prevail in the
period, with a sprawling area of surface high pressure over the
northern Plains/Rockies ridging into the Blacksburg forecast area.
In the wake of the frontal passage early Friday evening will be an
increase in northwest winds along with falling temperatures closer
to typical mid-March levels. Period of strongest wind gusts looks to
be between midnight to around mid-morning Saturday, where GFS shows
an overlap of 6-9 mb/6 hr pressure rises with an increase in 850 mb
northwest winds to 45 kts. Cold advection will also help raise
winds, but that being said it is not as robust as seen in stronger
post-frontal wind events. Do think that the winds could get close to
Advisory levels and will continue to mention gusty northwest winds
in the HWO. Other than falling temperatures - lows in the low 30s to
near 40 - will also see some shallow moisture banked against the WV
Appalachians which should support initial rain changing to snow
showers overnight. Better moisture is really more north/eastward
into Pocahontas County on upward into northeast WV, and snow growth
parameters are pretty unimpressive. Will therefore only show snow
amounts to an inch in western Greenbrier County with those
accumulations mainly on grass with limited impact. Lows upper 20s to
mid 30s west of the Blue Ridge, and into the mid/upper 30s to near
40 east.
Otherwise, Saturday into the first part of Sunday will feature
mostly clear skies and a return to more seasonable temperatures with
high pressure in control. Likely a pretty chilly Saturday night with
near optimal radiational cooling conditions. Air mass is quite dry
and good mixing should result in falling relative humidities each
afternoon. Highs mostly in the 40s to mid 50s Saturday/Sunday with
sub-freezing lows in most areas except in the NC Piedmont and the
foothills of NC.
Late Sunday and more into Sunday night, GFS and Canadian models show
a weak and moisture-starved Clipper low associated with a compact
shortwave trough/vort max moving across the Ohio Valley into the
northern mid-Atlantic. Low pressure generally skirts across the
northern Shenandoah Valley or into the MD/VA border overnight hrs.
Think at best this feature will result in an increase in clouds
across the western half of the forecast area with limited chances
for rain/snow showers from Mercer through Greenbrier County.
Accumulations again not expected to be substantial.
Forecast confidence is generally high, though is closer to moderate
on how strong wind gusts get Friday night/early Saturday.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 305 PM EDT Thursday..
An overall quiet, dry period looks likely looking into next week
with high pressure in control, and a mean longwave trough aloft.
There remains some disagreement for the Tuesday timeframe between
the GFS and the international suite of deterministic models on
handling a second shortwave which digs from the northern Plains into
the eastern Ohio Valley. GFS produces some measurable precip across
our southern counties into central NC as this trough digs into the
northern Carolinas, and this has been consistently shown in the last
couple model cycles. However equally as consistent has been the
drier ECMWF/Canadian guidance which digs this shortwave further
south and mainly leads to coastal cyclogenesis off the SC coast
Tuesday night - Wednesday. Will lean toward the drier solutions in
the ECMWF and Canadian in this period. Overall look for an extended
period of mostly clear weather with large diurnal ranges and
temperatures within a few degrees of mid-March normals.
Forecast confidence is moderate to high.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
As of 650 PM EDT Thursday...
Aviation conditions will gradually deteriorate from southwest to
to northeast overnight as moisture ahead of a cold front to the
west increases within deep southwest flow aloft. Bands of showers
may also arrive from the southwest, mainly after midnight, and
ahead of the actual cold front by early Friday morning.
Ceilings will drop to MVFR over most of the region this evening
followed by a period of IFR over parts of the mountains into
Friday morning as the showers cross the region. Lower ceilings
likely over the west near KBLF/KLWB around daybreak Friday,
then east to the Blue Ridge Friday morning, and points east by
early afternoon. Vsbys likely to remain mostly VFR but lower to
MVFR or brief IFR over the far west early Friday within
showers, and out east with any convection that could possibly
impact KLYH/KDAN later in the day. These showers will exit areas
west of the Blue Ridge by early afternoon as the front crosses
from the west. Some IFR cigs may occur at KBLF behind the
showers/front Friday as upslope westerly flow kicks in with
improvement back to post frontal VFR from west to east Friday
afternoon/evening.
EXTENDED AVIATION DISCUSSION...
After the frontal passage, isolated rain and snow showers could
occur in the western mountains during Friday night into early
Saturday where MVFR ceilings may linger. Conditions will improve
to VFR Saturday into Sunday as high pressure returns. VFR
should stick around early next week, though as a weak upper
disturbance passes Monday, and high pressure works in from the
north Tuesday, some lower clouds could occur along and west of
the Blue Ridge.
&&
.CLIMATE...
As of 305 PM EDT Thursday...
Warm low temps expected late tonight so record may be realized.
Caveat to this will be temps before midnight Friday night which
could be colder.
Friday 03/15/2019
Site Warmest Lows/Year
Bluefield 59 1990
Danville 57 1929
Lynchburg 59 1973
Roanoke 60 1973
Blacksburg 55 1953
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JH/WP
SHORT TERM...AL
LONG TERM...AL
AVIATION...AMS/JH/WP
CLIMATE...WP