Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/18/22
...Update to aviation forecast discussion...
.DISCUSSION...(This evening through Thursday)
Issued at 240 PM CST Thu Feb 17 2022
Key Messages:
- Clipper type system to bring a quick warm-up, light snow, and
gusty winds to the region. Some potential for snow squalls. A
winter weather advisory/wind advisory may be needed for
Friday.
- Unseasonable warmth on Sunday
- Winter storm with widespread accumulating snowfall becoming
increasingly likely for Monday through Tuesday of next week.
Tonight through Friday...
Water vapor satellite and heights show the 500mb trough axis has
pushed into the Upper Mississippi Valley and extends southwest
toward Kansas and New Mexico. Lightning and radar data highlight
the ongoing severe weather ahead of the trough across Alabama into
Tennessee with winter weather to the north of this area. Locally,
we continue to see cold temperatures in the single digits and
teens. The latest visible satellite image shows clearing west of
Rochester and Eau Claire.
A clipper type system will move into the region Friday. By morning,
the low level jet increase 45 to 55kts across parts of the area
resulting in strengthening south winds with gusts 15 to 30 mph. Some
lead energy combined with upper level jet support from the left
front exit region of the jet may result in enough saturation for
flurries during the morning hours. Cold morning temperatures will
rise into the teens...20s and possibly 30s in the far southwest by
noon. Snow over northern Minnesota is forecast to move into
northern Wisconsin with increasing frontogenesis aiding in snow
developing with the cold front Friday afternoon farther south across
the rest of the forecast area. Temperatures will range from the 20s
in the chimney area to the 30s for much of the rest of the area and
a few 40s for parts of MN/IA/wrn WI.
The lift through the dendritic growth zone is strongest across the
chimney area, however steep lapse rates accompany the
frontogenesis with the front. For now have a trace to 1 inch of
accumulation south of I94/I90 and 1 to 2 farther north for
Jackson/Clark/Taylor counties. Gusty southwest, west, northwest
winds accompany the frontal passage. Wind gusts look to increase
into the 35 to 50 mph range. In addition, the RAP is showing a
snow squall signal between 2pm and 6pm. A winter weather
advisory/wind advisory may be needed for parts of the area
Friday/Friday night.
Saturday into Next Week...
Saturday morning, temperatures starting out in single digits above
and below zero will increase throughout the day. The warmer
conditions will actually occur that evening as temperatures continue
to rise overnight. By Sunday morning temperatures are anticipated to
be in the mid 20s to low 30s. A ridge building aloft with surface
winds from the south/southwest and decent warm air advection will
easily help push temperatures above the seasonable average.
Although, temperatures at 850 mb reaching above zero up to 3 C are
not that anomalous according to the NAEFS. Still, high temperatures
at the surface are anticipated to top out in the 40s. A few
locations across the souther portions of the forecast area could
even see 50 degree temperatures.
Then attention turns to the next incoming winter system. Confidence
has been growing that a winter storm will impact the region for
early next week. The latest satellite water vapor imagery showed a
low pressure system spinning over the Pacific Ocean just west of the
Pacific Northwest region of the US. Model guidance has this
shortwave diving southward just west of the coastal states. As it
moves into the Baja California area, a longer wave trough is then
anticipated to dig through the western US. This trough then ejects
the shortwave energy from southern California into the midwestern
region. Shortwave energy wrapping around the upper-level system
along with decent isentropic lift around 290K will bring a prolonged
period for wintry precipitation chances beginning Monday morning
lasting into Tuesday night. Currently expecting widespread
accumulating snowfall as the main impact with this system. The most
likely period for greatest accumulations looks to occur Monday
night. Although not confident enough to include in the forecast at
this time, a few GEFS members are showing wintry mix chances along
the Wisconsin and Illinois border. Will continue to monitor this
system and resulting accumulation totals as the even draws closer
and details become more clear.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 544 PM CST Thu Feb 17 2022
High pressure will build across the area tonight. This high will
produce mostly clear skies and light winds into the early
overnight and then mid and high clouds will move into the area as
a warm front moves through the region.
With the wind increasing aloft faster than the surface, there may
be a few hours of low level wind shear. This looks more likely at
KLSE than KRST. Once the winds mix to the surface, they will be
rather brisk with sustained winds in the 20 to 25 knot range. Wind
gusts will range from 30 to 40 mph.
There may be a line of snow showers that move through the area
during the mid to late afternoon. These look to move through
between 18.20z and 18.23z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Zapotocny/MEP
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Bismarck ND
818 PM CST Thu Feb 17 2022
.UPDATE...
Issued at 817 PM CST Thu Feb 17 2022
Quick update to try to get a better handle on PoPs this evening
into the overnight. Current observations show light snow falling
across north central North Dakota, then extending down towards the
southwest corner of the state. The northern snow is likely tied to
the continuation of warm air advection, while the southwest snow
is likely being sustained by isentropic ascent on the leading edge
of a strong low level jet pushing in from the west. The RAP and
NAMnest seem to be doing a slightly better job resembling current
conditions than other models.
UPDATE Issued at 631 PM CST Thu Feb 17 2022
No significant changes are needed for this update. Areas of light
snow continue across northwest and north central North Dakota
ahead of a warm front lifting north and east. At this time, the
most persistent snow appears to located over northwest North
Dakota.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 402 PM CST Thu Feb 17 2022
The passage of Alberta Clipper will bring multiple weather concerns
through the short term period.
Currently, light snow associated with the initial WAA ahead of the
Clipper has been slowly moving east through the forecast area
throughout the day, and is likely to continue to do so ahead of the
main light precipitation expected with the core of the low pressure
system. The more widespread precipitation just mentioned is
currently across much of southern Saskatchewan and northeastern
Montana as shown by regional radar. This precipitation, falling
mostly as light snow (though some light rain cannot be ruled out
southwest), will continue to advance southeastward with the low,
moving through the forecast area this evening and overnight.
Accumulations from a trace to near an inch in the Turtle Mountains
can be expected.
On the backside of the low, strong northwesterly winds associated
with cold air advection and pressure rises will develop across the
area. The strongest winds are expected to begin around 06Z west and
central to 09Z east which is when headlines will begin. West and
across much of the central, little to no blowable snow exists with
little accumulation forecasted, so a Wind Advisory has been issued
to cover the strong wind threat. Further east, not only are slightly
stronger winds expected closer to the low pressure center, but there
is also more snow to blow around. Considering parts of north central
and eastern North Dakota were experiencing reduced visibilities due
to blowing snow on Tuesday behind a weak cold front, and after
talking with some emergency managers about snow cover, the decision
was made to go with a Blizzard Warning for Rolette and Pierce
Counties and a Winter Weather Advisory for counties just to the
south and west, all for blowing snow impacts. Further south, mainly
the remainder of the James River Valley, strong winds are expected
but there is less confidence in blowing snow impacts, so we decided
to go with a High Wind Warning. With that being said, there could
still be some blowing and drifting snow at times out in the open
country.
Aside from the headlines, convective snow showers will be possible
during the day tomorrow behind the cold front with strong cyclonic
flow aloft and moderate lapse rates. It is uncertain at this time
whether these showers will be cellular in nature or possible congeal
into a band (or bands of showers). Either way, these showers would
likely result in rapid onset, brief, significant visibility
reductions and locally enhance the already strong wind gusts.
Heading into Friday night, with temperatures falling to as low as
the teens below around the Turtle Mountains and winds around 10-15
mph, another Wind Chill Advisory will be needed for most of our
northern and eastern counties.
.LONG TERM...(Saturday through Thursday)
Issued at 402 PM CST Thu Feb 17 2022
An active weather pattern will continue through the beginning of
the long term period.
Ridging aloft briefly builds in on Saturday which will result in
temperatures quickly warming to near 50F across the southwest to
near freezing around the Turtle Mountains for Saturday afternoon.
Saturday night the next clipper moves in, the location of the low
differs between the models. Most ECMWF members have it coming in
over the ND/MN border, same with the NAM. Most GFS members have it
moving through North Dakota. For the snow band location, not much
has changed in the last 24 hours. Most GFS members keep the snow
north of the Canadian border and most of the ECMWF members have
the snow right on the International Border but some have it
sliding south through central North Dakota. Snow amounts are
expected to be low, both the ECMWF and NBM 4.1 have less than half
an inch between the International Border and Highway 2. The NBM
4.1 paints the Canadian border with an inch, where all the models
agree on the snow.
Sunday the temperatures look to drop during the day, depending on
the timing of a cold front dropping south out of Canada.
Therefore, the temperature spread is large for high temperature.
Strong CAA and strong pressure rises are associated with the
front. Again, not much has change with this in the last 24 hours.
The post frontal areas look to be in the single digits. Areas
ahead of the front will remain in the 20s and 30s. Pressure rises
do look a bit stronger with the front. NBM 4.1 has winds gusting
to 30 kts in the southern James River Valley Sunday afternoon.
High temperatures Monday are in the negative single digits across
the FA except the southwest which should just barely stay above
zero after the front fully moves through. We transition to split
flow aloft Sunday, ending the clipper parade for now.
For Monday, there is some agreement between the GFS and ECMWF
ensembles on location, both seem to target central South Dakota
and Minnesota for the heaviest snow. For North Dakota most
ensembles members for both models have lighter snow in the
southern part of the state. Snowfall amounts could be the biggest
unknown. The NBM 4.1 has a large spread in snowfall. The 10th to
90th percentile is 0 to 8 inches for most of the FA. Cluster
analysis show a large spread in QPF as well. Synoptically the best
lifting is over western and central South Dakota with negative
Q-vectors and the right entrance region of the jet streak. It
would makes sense that the highest snowfall would stay south of
us. An Arctic high pressure moves in Tuesday keeping temperatures
in the single digits below and above zero. Confidence in this is
fairly high with the temperatures spread in the NBM being low.
Wednesday morning a shortwave looks to move through with a small
ridge right behind. No precipitation is expected as of now with
that.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 817 PM CST Thu Feb 17 2022
Light snow will remain possible across western and central North
Dakota through the evening. Periods of MVFR ceilings and MVFR to
IFR visibility can be expected under falling snow. It will become
very windy tonight through Friday afternoon. Westerly winds
increasing to around 20 kts overnight will turn to the northwest
and strengthen to 25-30 kts behind a cold front plunging down from
Canada Friday morning. Gusts near 50 kts are possible from KMOT
to KJMS. A few hours of MVFR ceilings are likely with the cold
front, which could also produce some scattered snow showers.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from midnight CST /11 PM MST/ tonight to 6 PM CST
/5 PM MST/ Friday for NDZ001>003-009>011-017>021-031>035-040>046.
Blizzard Warning from 3 AM to 6 PM CST Friday for NDZ005-013.
Winter Weather Advisory from 3 AM to 6 PM CST Friday for NDZ004-
012-023-025-037.
High Wind Warning from 3 AM to 6 PM CST Friday for NDZ022-036-
047-048-050-051.
&&
$$
UPDATE...Hollan
SHORT TERM...Gale
LONG TERM...Smith/Gale
AVIATION...Hollan
Area Forecast Discussion
National Weather Service State College PA
1027 PM EST Thu Feb 17 2022
.SYNOPSIS...
A cold front will push southeast across the region late tonight,
dropping temperatures drastically from current lofty numbers.
Flooding possible in the N tonight and Fri, some points may
linger into the weekend. Strong Alberta Clipper passing through
on Sat will generate strong winds, snow showers, and possibly
snow squalls. Temperatures warm up for Mon and Tues, and more
rain on the way later Mon-Tues.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Radar late this evening shows rain falling across the entire
forecast area in region of warm advection and plume of deep
moisture along powerful southerly low level jet. Near term
guidance continues to target the northern mountains for the
heaviest rain late this evening due to orographic enhancement. A
few lightning strikes noted at 01Z along cold front over Ohio,
where some limited capes are accompanying strong forcing with
fropa. Latest near term models suggest a few rumbles are also
possible as the front comes through central Pa late tonight.
Upstream wind gusts have not been that impressive despite strong
winds aloft this evening and latest model soundings suggest
most locations will fall short of advisory criteria overnight.
However, will maintain the possibility of localized 40kt+ gusts,
mainly where momentum transfer is greatest on the lee (north)
side of ridges.
A brief change to mixed precipitation still appears likely late
tonight over the northern mountains, before drier air arrives
behind cold front. Any snow accums should be less than an inch.
However, will maintain the current wint wx advisory over
Warren/Mckean counties for the possibility of a brief period of
fzra late tonight.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
The cold front and associated precipitation should have cleared
the southeast part of the forecast area by dawn Friday. In its
wake, lingering lake enhanced, orographic snow showers/flurries
are expected over the Allegheny Plateau. Falling inversion
heights and a largely frozen Lk Erie should result in no
accumulation in most spots and perhaps a dusting over the Laurel
Ridge of western Somerset/Cambria counties.
The approach of high pressure should cause lake effect stratocu
to break up as the day progresses, with clearing skies
occurring during the morning over the southeast counties and
during the afternoon over the Alleghenies.
Clearing skies and a diminishing breeze should allow temps to
fall quickly Friday evening, then increasing clouds/warm
advection ahead of an approaching cold front will likely cause
readings to level off or rise late at night. Latest guidance
supports light snow arriving late at night over the northwest
mountains, as southwesterly low level jet arrives ahead of cold
front.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A clipper and associated shortwave trough will move out of the
Great Lakes into the Northeast US on Saturday. This system will
drag a cold front across the CWA between about 12z in the NW
and 18z in the SE. A period of light snow is possible across the
NW ahead of the front, followed by possible heavier snow
showers/squalls along the cold front itself. The environment
will be at least marginally favorable for snow squalls with
lapse rates Sat morning steepening in the lowest 2-3km AGL and
southwesterly 0-3km wind shear of 50+ kts. The limiting factor
may be moisture, particularly across eastern portions of the CWA
where RHs will be lower, but both the 3-km NAM and 48-hour HRRR
do support the possibility of a nearly continuous snow
band/squall along the cold front stretching N to S across PA and
potentially holding together all the way into eastern PA. Air
temps on Sat will range from the low 20s in the NW to the mid
30s in the SE, leaving much of central PA including the I-80
corridor vulnerable for flash freeze impacts on roadways if snow
squalls do occur. We will continue to keep a close eye on this
potential snow squall event.
The other big weather story on Saturday will be another round of
strong winds. The pressure gradient will tighten on Sat as the
departing 1000 mb clipper system is replaced by an arriving 1030
mb high pressure system. The result will be strong westerly
winds with gusts of 40-50+ mph possible Sat before diminishing
late Sat night. The combination of strong winds and temps in the
teens Sat night will make for wind chills in the single digits
across the north.
As high pressure shifts offshore on Sunday, return flow will usher
in milder temps. Sunday should be mostly sunny with less wind but
still breezy, with temps warming into the 40s. Monday looks quite
pleasant with temps warming to the 50s with a mix of sun and
clouds and light winds.
Medium range guidance supports a good chance of rain Tuesday
associated with a wave of low pressure lifting out of the Miss
Valley, then across the eastern Grt Lks. Drier, cooler
conditions should arrive Wednesday, as trailing cold front
clears the area. Focus then shifts to a developing area of low
pressure lifting north from the Gulf Coast. Plenty of
uncertainty with regard to the track of this system. However,
enough agreement in timing among ensemble members to ramp up
POPs Thursday PM. With a blocking high over New England, odds
currently favor at least some wintry precipitation with this
system.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Conditions now IFR at BFD, and are starting to slip elsewhere.
Fog stuck in the valleys of the central mtns where we have not
yet mixed. Perfect example is here at the office where visby is
P6SM, KUNV is 6SM, too. But FG is trapped in the hollow between
us and KUNV. When the wind picks up at the central sites, they
should mix higher and warm up a little. This could allow
cigs/vis to rise, too. Still expecting JST to dip to IFR this
aftn, and hang there for the next 15/24 hrs. LLWS still a big
issue, and will continue to be all night in most places. Behind
the front (NW by 03Z and SE by 12Z), the winds aloft will start
to decrease. But, mechanical mixing will continue to keep the
gusts in the 20s thru the day. Gusty winds will occur again on
Saturday, given cold air aloft and the passage of a mainly-dry
cold front attached to an Alberta Clipper passing well to our N.
After a short break of VFR Fri and Sat in most places, an
Alberta Clipper will push across on Sat. The conditions will be
favorable for SHSN and even stronger/gustier squalls. These will
be short-lived, and will likely decrease in intensity as they
move into and out of the central mtns into the valleys of the
SE. Large-scale gusts will already be in the 30s or higher.
Outlook...
Sun...VFR. 20-25kt wind gusts from 180-210 degrees.
Mon...No sig Wx.
Mon PM-Tues...Deteriorating conditions with RA. Lowest cigs/vis
on Tues. LLWS possible.
&&
.HYDROLOGY...
A few river points to the west of the divide are fcst to get
well above caution and some into flood tonight and Fri. Current
thinking is to hold off on issuing warnings to see if going
rainfall numbers are looking good to pan out. Clarion R at
Ridgway is fcst to just touch FS, and J-burg (upstream) is to
get close to MDT flooding. But, lots of this is based on QPF and
SWE/meltwater. Will continue to monitor stages and
trends/results in precip gages. Ice is still a wild card.
Prev...
The 1-1.5" QPF over the nrn tier will combine with melt water
to possibly result in minor flooding along small streams and
creeks later Thurs-early Fri. There is also still a little ice
on the waterways, raising the possibility of some ice jam
flooding occurring. Have chosen to post a flood watch from noon
R thru noon F over the nrn mtns.
The quick passage of the cold front early Thurs night should
decrease the small stream flood potential in the watch area by
sunrise Friday, but the larger waterways will then have the
potential to climb out of their banks.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 6 AM EST Friday for PAZ041-042.
Wind Advisory until 7 AM EST Friday for PAZ012-017>019-024>028-
033>035-037-041-042-045-046-049>053.
Wind Advisory until 9 AM EST Friday for PAZ036-056>059-063>066.
Flood Watch through Friday morning for PAZ004>006-010-011-037.
Winter Weather Advisory until 9 AM EST Friday for PAZ004-005.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/Dangelo
LONG TERM...Fitzgerald/Colbert
AVIATION...Dangelo/Banghoff
HYDROLOGY...
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1023 PM EST Thu Feb 17 2022
.UPDATE...
Issued at 1020 PM EST THU FEB 17 2022
Cold front is starting to enter from the west at this hour, and
will quickly march through eastern KY over the next several hours.
Winds along and just behind the front are gusting 40-50 mph so
will continue to hold the wind headlines through at least 1 AM.
Also made some minor adjustments to the snow grids overnight into
Friday morning. Updates sent to NDFD and web servers.
UPDATE Issued at 810 PM EST THU FEB 17 2022
Freshened up the grids with the latest obs. Strongest winds
earlier this evening were ahead of the line of convection in some
areas where there was some brief drying. Cold front is currently
from Louisville down to Bowling Green, and will continue to march
east this evening and will push through eastern KY by around 06Z.
HRRR soundings over far SE KY show a low inversion in place just
below the strongest winds aloft, which explains why winds across
the mountains have been lackluster thus far. However, with
convection moving across the area this evening, there is still a
chance that some of those winds aloft can get mixed down, so will
leave the headlines up for now. Updates sent to NDFD and web
servers.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 457 PM EST THU FEB 17 2022
At 21z, radar showed rain increasing across the forecast area
ahead of a powerful cold front. An intensifying 70-80 knot 850 mb
jet was analyzed just ahead of the boundary. As the jet has
increased, some downslope drying has become evident near and
downwind of Pine Mountain. The ECMWF ensembles and some of the
CAMS have shown a persistent bullseye of 58+ mph gradient wind
gusts (mainly between 6 and 9 PM) immediately downwind of Pine
Mountain. Given the observed downslope drying, seemed prudent to
further expand the High Wind Warning into these areas. The most
likely impacted areas will be the higher ridges of Black and Pine
Mountains as wells areas immediately downwind, generally to the
south of the Hal Rogers and Highway 80 corridor. In the deeper
valleys of the Warning area, anticipate wind gusts to generally
remain in in the 40 to 50 mph range ahead of the line, but could
gust higher with any stronger convection. McCreary County was
added to the High Wind Warning given the observed upstream wind
gust of 55 to 60 mph at the Scott County Airport but suspect that
most impacts will be limited to the southeastern part of the
county near the higher mountains. The remaining forecast area is
under a Wind Advisory for peak gusts of 40 to 50 mph.
Aside from the strong gradient winds, we are also watching the
possibility for strong to severe showers and storms along the
front. Shear remains extreme and the instability is very minimal,
but if any deeper convection is able to maintain, damaging wind
gusts are the primary threat. It actually appears that the strong
mid-level flow is pushing the convection out of the best
instability axis into more stable air ahead ahead of the front. If
this continues, the threat for tornadoes, will be almost nil. The
heaviest line of showers and storms is expected to reach our
western counties by around 6-7 PM and will then push east and exit
Pike County by 10-11 PM.
Behind the front, expect a few lingering showers through the
remainder of the night, gradually transitioning to snow showers
and flurries as temperatures fall below freezing. A mostly cloudy
and cold day is on tap for Friday--highs will remain in the 30s at
most locations. Snow showers and flurries will likely hold on
through the morning hours ahead of the upper level trough axis. A
wedge of surface high pressure follows Friday evening with drier
air, clearing skies, and seasonably cold temperatures for Friday
night.
.LONG TERM...(Saturday through Thursday)
Issued at 525 PM EST THU FEB 17 2022
The models are in very good agreement concerning the long wave
pattern for this weekend and into next week. A transition to more
zonal flow takes place east of the Rockies through the conclusion
of the week. Meanwhile, upper level ridging will be sharpening up
across the eastern Pacific. A cutoff low will be opening up and
ejecting east out the Baja California, while inbound short wave
energy from southwest Canada will allow for deeper troughing to
take shape from the northern Rockies/Great Basin down through the
Desert Southwest into next week. This sets up warm and moist
southwest flow across the Mississippi Valley. At the surface, a
slow-moving baroclinic zone will shift southeast across the Ohio
and Tennessee valleys, with above normal temperatures and wet
conditions returning to region. The probability of persistent
rainfall is high through the period; however, there is still
plenty of variability regarding the placement of heavier rainfall
amounts and eventual hydro concerns. Have stayed pretty close to
the blended guidance for the forecast, besides allowing for a
slower onset to the precipitation, as models have trended more
delayed compared to yesterday.
A dry cold front will pass through eastern Kentucky on Saturday,
with low relative humidity expected. Highs have trended a bit cooler
compared to yesterday, generally in the low to mid 40s. The dry
air will continue on Sunday, with highs trending a good 15 degrees
warmer, generally upper 50s for most locations. Dry weather will
hold on through early Monday morning, before rain chances ramp up
especially from Monday night onward, with the approach of the
slow-moving cold front from the northwest. Temperatures will
average well above normal through Tuesday, with highs in the 60s
and lows in the 40s and 50s. Temperatures will cool down behind
the front by the middle of next week, with highs retreating to
mainly the 50s, and lows in the 30s and 40s. Depending on where
the front stalls to our southeast, there is fairly low confidence
in these numbers holding up well this far out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 625 PM EST THU FEB 17 2022
Poor flying conditions to start the 00Z TAF period with MVFR and
at times IFR ceilings. Rain showers and isolated thunderstorms
will continue along and ahead of an approaching cold front that
will cross the area late tonight, with reduced visibility expected
in some of the heavier showers. S/SW winds ahead of the front
will continue to be gusty, with 30-40 kt gusts expected this
evening. Winds turn to the W/NW after the frontal passage and
gradually subside overnight. Ceilings will remain IFR/MVFR
overnight with improvement expected Friday morning. A return to
VFR is expected at all locations by Friday afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 1 AM EST Friday for KYZ044-050>052-058>060-
068-069-079-080-083-104-106>112-114-119.
High Wind Warning until 1 AM EST Friday for KYZ084>088-113-
115>118-120.
&&
$$
UPDATE...CMF
SHORT TERM...GEERTSON
LONG TERM...GEOGERIAN
AVIATION...CMF
Area Forecast Discussion
National Weather Service Louisville KY
746 PM EST Thu Feb 17 2022
.Mesoscale Update...
Issued at 743 PM EST Thu Feb 17 2022
The line of enhanced showers/convection has pushed east of the
region and the severe threat is over for the region. Of greater
concern will be lingering flooding for the next few hours due to a
widespread one to three inches of rain that fell. With the bulk of
the rain now in eastern Kentucky, we should see some gradual
improvement with the flooding through the overnight hours.
Issued at 504 PM EST Thu Feb 17 2022
The surface cold front is pushing near the Ohio River at this hour.
South of the cold front, a narrow but enhanced line of
showers/convection extends roughly along a SW to NE oriented line
from Logan County (KY) to Franklin County (KY). Model soundings
indicate a nearly moist adiabatic profile with little to no
instability ahead of this line. A small stable layer remains in
place in the low levels across much of central KY, but may have
eroded across portions of southern KY where surface dewpoints have
climbed as high as 63 degrees in response to low-level theta-e
advection.
The enhanced shower/convective line is nearly parallel to the 0-3km
shear vector which would indicate low severe potential at this time.
Main thing we`ll be watching for over the next few hours will be any
surges, bows, or kinks that develop in this line and would make the
UDCZ perpendicular to the 0-3km shear vector. It`s in those areas
where we`d have the potential for concentrated severe wind gusts and
brief spin up tornadoes.
&&
.Short Term...(This evening through Friday)
Issued at 319 PM EST Thu Feb 17 2022
Afternoon surface analysis reveals a 998 hPa surface low just
east/northeast of KPAH. Surface cold front is surging through
western KY and passed through KPAH just recently. Much colder air
is already filtering into far western KY with the Ballard and Fulton
county KY Mesonet stations already dropping into the lower 40s.
Mesoanalysis shows greatest surface pressure height falls along the
WK/BG Parkways over the last few hours. In general, we expect the
surface low to move along the Parkways this afternoon with a
trailing cold front. Widespread rainfall across southern IN and far
northern KY has kept static stability in check and the threat of
severe weather, generally along and north of the Ohio River is very
low. The main concern over southern IN and far northern KY will be
the moderate to heavy rainfall which may lead to some hydro issues.
Further south, regional radars show a shallow, but strongly forced
convective line develop in advance of the surface cold front.
Persistent theta-e and moisture advection is rather strong in this
region with some higher quality moisture working into far southern
KY. RAP model soundings along our southern counties suggest lower
static stability here and it`s likely that the theta-e and moisture
advection are probably eroding the temp inversion aloft. Continued
influx of moisture and warm advection aloft should continue across
southern and southeastern KY this afternoon. Highest risk of severe
weather looks to be along and southeast of the surface low track
which would be generally areas south of the WK/BG Parkway. Within
this region, the strongly forced convective line will have the
potential to mix down some of the higher momentum air aloft and
produce wind gusts in excess of 60kts. Low-level shear is very
strong as well and given the good directional shear, a couple of
spin up tornadoes (within bowing segments and/or line breaks) will
be possible. Based on current projections, this line should get into
the I-65 corridor by 4-5 PM EST and then over into the I-75 corridor
by 7-8 PM EST.
In addition to the strong/severe threat, moderate to heavy rainfall
will continue to move across southern and east-central/south-central
KY this evening. Up to another 1-2 inches of rainfall may occur and
this may bring additional hydro issues, mainly in the Flood Watch
area. Current flood watch area looks good and no headline changes
are expected with this issuance.
The expansive rain shield has really kept a lid on the wind gusts
today and gradient winds have been below advisory criteria in many
areas since sunrise. However, there will be a decent pressure
fall/rise couplet with the front and post frontal winds will be an
issue this evening. The pressure gradient looks to remain elevated
for a bit longer and we plan on extending the Wind Advisory out a
few extra hours (18/06Z).
Behind the front this evening, a rapid and impressive temperature
drop will be seen. Current data continues to show 5-6 deg/hr temp
drops behind the front, so while spots are in the upper 50s to lower
60s this afternoon, temperatures will rapidly fall into the 30s this
evening. Model soundings show abundant dry air punching into the
region so behind the front, a sharp cut off in precipitation is
expected. Can`t rule out a few snow flurries across southern IN and
far northern KY late this evening and into the overnight hours, but
the overall threat of accumulations remains very low. Given that
gradient winds will remain elevated, the gusty winds should result
in roads drying out pretty well before temps drop into the mid 20s,
but a few slick spots can`t be ruled out for Friday morning.
Overnight lows look to cool into the lower-mid 20s.
For Friday, high pressure will start to build into the region with
partly to mostly sunny skies expected. It will be a cold day with
highs in the middle 30s.
.Long Term...(Friday night through Thursday)
Issued at 232 PM EST Thu Feb 17 2022
A dry weekend can be expected as upper level ridging and surface
high pressure overspread the region. And though a clipper system
will scoot through the Great Lakes, cool NW flow and limited
moisture availability will keep any precipitation well to our north.
CAA on NW flow will limit diurnal warming with expected highs in the
mid 30s across southern Indian to the mid 40s across south central
KY. But as the surface high pushes east to the coast, return flow
and WAA will see quite the increase in temperatures Sunday with
highs 15 to 20 degrees warmer than the day prior. Tight pressure
gradient created from the clipper also will result in a breezy
weekend with gusts in the 15-20mph range both days.
A stout shortwave will drop south out of the PNW by the end of the
weekend and carve out a deep central CONUS trough as ridging remains
in place over the eastern seaboard. This synoptic setup will allow
for repeated perturbations resulting in periods of rain beginning
Monday through Thursday with rough estimates of total QPF ranging
from 1 to 4 inches over this time frame. This could result in
widespread minor river flooding by the latter half of next week with
some moderate river flooding possible. Also worth noting, prolonged
return flow will see temperatures rise into the 60s Monday and
Tuesday.
By Tuesday, models largely agree that a low pressure system will
push a frontal boundary into the OH Valley. There are some dynamics
falling into place as our area appears to fall between the right
entrance region of a northern stream jet max and the left exit
region of a southern stream jet max. This will result in a robust
LLJ with impressive shear values being advertised. So another
potential high shear low CAPE scenario will need to be watched for
Tuesday.
The low pushes east Wednesday but the boundary gets hung up just to
our SE setting the stage for more PoPs Wednesday and Thursday.
Modified cP airmass north of the boundary could also result in
periods of light wintry precip during this time frame, though
confidence remains low as to the extent or the impacts at this time.
&&
.Aviation...(00Z TAF Issuance)
Issued at 653 PM EST Thu Feb 17 2022
IMPACTS: Breezy and variable winds, IFR/MVFR ceilings, rain ending
DISCUSSION: As the surface cold front moves across the area this
evening, winds will shift from SW to NW and will be strong
immediately behind the front before easing by 18/06-09Z.
Precipitation associated with the front has cleared HNB, SDF, and
BWG and is expected to clear LEX by 18/03Z. Visibilities are not
expected to be of concern except at LEX as the last bit of rain
moves through.
Behind the front, a low stratus deck will persist across the region
through 18/14-17Z, with ceilings expected to vary between IFR and
MVFR levels through the nighttime hours. Confidence in ceilings is
fairly low, as upstream observations at this hour are varying
between MVFR and IFR. Generally expect more optimistic ceilings at
SDF and BWG, with more pessimistic ceilings at LEX and HNB.
By mid-morning tomorrow, expect skies to clear from W to E with VFR
conditions returning and light W/NW winds.
CONFIDENCE: Medium-low on ceilings, medium-high on winds, medium-
high on precipitation, medium-high on visibilities.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch until 9 PM EST /8 PM CST/ this evening for
INZ076>079-083-084-089>092.
Wind Advisory until 1 AM EST /midnight CST/ Friday for
INZ076>079-083-084-089>092.
KY...Flood Watch until 9 PM EST /8 PM CST/ this evening for
KYZ023>040-045-053.
Wind Advisory until 1 AM EST /midnight CST/ Friday for
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
&&
$$
Mesoscale...DM
Short Term...MJ
Long Term....CG
Aviation...CSG
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
827 PM CST Thu Feb 17 2022
.UPDATE...
Issued at 827 PM CST Thu Feb 17 2022
Expanded the Wind Advisory across the rest of the region Friday
afternoon and evening with widespread gusts of 45 to 55 mph expected.
Forecast soundings from the NAM, GFS, RAP, and HRRR all indicate a
period immediately following the cold front with 50+ kt winds at the
top of an unstable boundary layer. Upright instability with 50-100
J/kg of SBCAPE will easily allow the stronger winds aloft to mix to
the surface and localized gusts of 60 mph are likely. If the CAPE
intersects the moist DGZ, which appears likely it will, then
scattered heavy snow showers or snow squalls should be expected
within this same period and travel would become dangerous. This
period may only last a couple hours. The Wind Advisory may need to
be converted to a Winter Weather Advisory if snowfall amounts are a
little heavier than currently predicted, or the duration of snow
showers is longer than an hour or two.
&&
.DISCUSSION...(This evening through Thursday)
Issued at 141 PM CST Thu Feb 17 2022
KEY MESSAGES:
- Winter Weather Advisory across west central Minnesota for blowing
snow on Friday. The potential exists for snow squalls as the front
passes tomorrow, with the main concern being reduced visibility.
- Wind Advisory from central Minnesota and southward for strong winds
on Friday. Gusts in excess of 45 mph are likely.
- Accumulating snowfall chances remain for early next week.
Temperatures will drop to the single digits below zero overnight.
Strong and widespread winds will move in tomorrow morning as this
front passes. Despite sustained winds between 20 and 30 mph,
temperatures are still anticipated to reach the upper 20s to mid 30s
(above zero!) tomorrow afternoon. The gusty winds will be there to
remind you it is still February in the Midwest with area-wide
apparent temperatures largely in the teens. Northwesterly winds will
pick up around lunchtime and hold strong through the early evening
hours. The strongest gusts will likely be between 2-7PM and reside in
the 40-45mph range. This will create the greatest cause for concern
in any areas that see snowfall tomorrow, as these blustery winds will
greatly reduce visibility. Speaking of snowfall, the greatest chance
for precipitation will be in our northern CWA during the morning and
become more widespread by the evening. This being said, snow amounts
are expected to be light, with up to 1.5 inches possible in west
central WI and around a half inch in the Metro. Southwest MN could
see just a dusting.
Medium confidence remains in the potential for snow squalls.
Sufficient agreement amongst the models indicates brief, but intense,
snowfall is possible as the front passes. This could lead to a large
reduction in visibility and difficulty during the evening commute.
Beyond Friday`s system, the weekend should be quiet. Sunday will be
the warmest day, with the potential to see 40 degree temperatures
across a good chunk of the area. This warm-up will be brief, as
temperatures will plummet to the single digits on Monday ahead of a
front. Tuesday`s temperatures will be similar but slightly colder
than Monday`s.
The next chance for significant snowfall returns early to mid-week
as a broad trough approaches the region. With this, there is an
increasing potential for a widespread snow event in our region.
While still very early, decent agreement between models indicates a
substantial amount of snowfall by Wednesday. As the event approaches
and models trends are able to be analyzed, more will be known on this
system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 548 PM CST Thu Feb 17 2022
Clouds will increase tonight from west to east with some MVFR/IFR
snow possible overnight across central MN and into eastern MN and WI
Friday morning. A cold front will push through mid morning to mid
afternoon Friday, shifting winds west northwest and increasing gusts
substantially into the 40-45 kt range. Some peak gusts could reach 50
kts. A short window (2-3 hrs) of low level instability could result
in some snow squalls with brief periods of IFR or LIFR visibilities
in +SHSN. Much drier air will move in late Friday and winds will
gradually ease Friday night.
KMSP...Most of the light snow will remain north through early Friday,
but could see a period of MVFR visibilities. The front will arrive
around 19Z with a rapid shift and uptick in wind soon thereafter. The
best chance for snow squalls will be between 19-21Z, but the general
window is within about +- 1 hour of those times.
/OUTLOOK FOR KMSP/
Sat...VFR. Wind W bcmg S 10-15 kts.
Sun...VFR. Chc MVFR cigs. Wind S5-10kts, bcmg NW 15-20kts.
Mon...VFR. Chc MVFR cigs. Wind NE 10-15kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Wind Advisory from noon to 9 PM CST Friday for Anoka-Benton-Blue
Earth-Brown-Carver-Chippewa-Chisago-Dakota-Faribault-Freeborn-
Goodhue-Hennepin-Isanti-Kanabec-Kandiyohi-Lac Qui Parle-Le
Sueur-Martin-McLeod-Meeker-Mille Lacs-Morrison-Nicollet-Ramsey-
Redwood-Renville-Rice-Scott-Sherburne-Sibley-Stearns-Steele-
Waseca-Washington-Watonwan-Wright-Yellow Medicine.
Winter Weather Advisory from 9 AM to 9 PM CST Friday for Douglas-
Pope-Stevens-Swift-Todd.
WI...Wind Advisory from noon to 9 PM CST Friday for Barron-Chippewa-Dunn-
Eau Claire-Pepin-Pierce-Polk-Rusk-St. Croix.
&&
$$
UPDATE...Borghoff
DISCUSSION...Marten
AVIATION...Borghoff
Area Forecast Discussion
National Weather Service New York NY
1018 PM EST Thu Feb 17 2022
.SYNOPSIS...
A strong cold front moves across the region late tonight into into
Friday morning. Weak high pressure briefly builds late Friday and
Friday night. A cold front will move through Saturday afternoon,
followed by high pressure building in and passing to the south and
east on Sunday into Monday. A low pressure system will approach from
the southwest on Tuesday and pass to the north Tuesday night. High
pressure builds back in briefly on Thursday before another low
approaches north and west of the area on Friday.
&&
.NEAR TERM /THROUGH FRIDAY/...
Low pressure lifts north of the area overnight into Western and
Northern NY while dragging a strong cold front through towards
daybreak. Any patchy fog / dense fog has dissipated along the
south shore of Queens and Long Island as the rain overspreads
the area. Thus, the SPS for locally dense patchy fog for right
along the ocean has been allowed to expire. Look for rain
varying in intensity for the next several hours, before the cold
front moves through very late. Some of the higher res guidance
does show squall line potential. This would increase the chance
of bringing down strong and damaging winds, if even for a very
brief time getting towards 11-13z from west to east.
Ahead of the cold front, models are in good agreement with a
strong llj (70-80kt@950mb) developing across eastern coastal
areas overnight into the early morning. With water temps in the
lower 40s, the challenge is how much of the LLJ will be able to
mix down in a strongly inverted low-level environment. Models
generally similar for the past day or two regarding wind speeds.
NBM has trended upward with gust magnitude from 24 hrs ago,
with 4.0 indicating 45-50kt gust potential for LI and SE CT,
while version 4.1 continues to show a 50-55kt potential for LI/
SE CT. HRRR 10m wind gust potential, which has shown to be
skillful (albeit a little high), continues to indicate the
potential for 55-60kt gusts for LI and SE CT, and has shown this
for at least the past 24 hours. Additionally, SPC HREF
indicates high potential for 30kt sustained winds across LI/SE
CT as well (not common), supporting the strong to damaging wind
gust potential.
Confidence remains high in a strong wind (wind advisory) event
tonight across the entire area, including NYC (45-55mph gusts), with
moderate to high confidence in high winds gusts (55-65mph) for LI
and SE CT under the core of the 75-80 kt llj. The timing for peak
strong to high wind gusts continues to center around 6-12z Fri. The
cold front pushes through during early Friday morning, with winds
shifting to W/NW. Potential for wind advisory gusts of 40-50mph
Friday morning areawide with wind shift as lapse rates rapidly
steepen/deepen. Advisories and warnings remain unchanged - from 11pm
tonight through 10am Friday.
Regarding rainfall, anomalously high moisture and weak elevated
instability will present a 3-6 hr window where moderate to heavy
rain could occur. The limiting factor for heavy rainfall amounts
will be the quick movement of the cold front, racing ahead of
shortwave forcing. Still looks like mostly 1/2 to 1 inches of
rainfall with a chance of locally higher amounts. Steadier rainfall
develops from west to east this evening through midnight, with
narrow bands of heavy rain indicated by CAMs late tonight with llj
and along/ahead of cold front. Rain will quickly come to and end
early Friday morning from west to east with the cold frontal
passage. Potential impacts appear to minimal - see the hydrology
section below.
High pressure then builds in, the pressure gradient weakens,
and with the initial burst of strong cold air advection done,
gusts should settle into the 30 to 35 mph range for Friday
afternoon. It will be drying out with sunshine, but temperatures
will be dropping through the day (50s early to 30s late PM)
with modified polar airmass advecting in.
&&
.SHORT TERM /FRIDAY NIGHT/...
A high pressure ridge noses in Friday night, with potential for a
window of radiational cooling with a mostly clear sky and light to
calm winds. Low temps dropping down into into the teens across pine
barrens and interior with 20s elsewhere.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Only minor changes made to the extended with this update, with a
cool, active pattern through early next week followed by a warm up.
On Saturday a potent northern stream shortwave trough will swing
across and drive a cold front through. Enough H9-7 moisture/lift/
instability will be present with the frontal passage to generate
a quick burst of snow showers that could at least coat the ground,
especially north and east of NYC. W-NW winds after fropa could
gust as high as 40-45 mph for a few hours during the late day or
early evening, quickly ushering in a much colder air mass with
lows by Sunday morning in the teens and lower 20s.
Winds should quickly diminish late Sat night into Sunday morning and
then turn SW by afternoon as high pressure quickly builds across to
the south given the fast progressive zonal flow aloft following
trough passage. Slowed initial moderation in temps forecast by the
NBM in the return flow by blending with colder 00Z GFS/ECMWF MOS
guidance, with highs on Sunday only in the 30s to near 40, and lows
Sunday night from the mid 20s to lower 30s.
A mild spell with daytime highs mostly in the 50s is forecast for
Mon-Wed courtesy of deep layer SW flow aloft ahead of a low pressure
system moving from the srn Plains to the lower Great Lakes Mon-Tue,
then passing to the N Tue night. Rain with this system could arrive
as early as late Mon night, but is more likely daytime Tue into Tue
night. Rain showers expected on Wed via a trailing cold frontal
passage, followed by a cool-down Wed night as strong high pressure
builds from the west.
By Thursday, weak ridging aloft and cool high pressure build north
of the area, settling over upstate NY. Models then show a quick
moving surface low with associated precipitation approaching from the
OH Valley by Thursday.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
A strong cold front approaches from the west and pass through
towards or just after 12z Friday.
Rain has now overspread the city and western terminals and will
continue to move east, with rain arriving for the eastern terminals
by 5-6z. Any low stratus / fog dissipates for eastern terminals with
the onset of rain. Look for IFR conditions for the eastern most
terminals, otherwise MVFR conditions should prevail, although KHPN
and KSWF should have IFR conditions at times through 8z or so. There
is also a low chance for a thunderstorm during the overnight. Quick
improvement to VFR expected about 1-2 hours behind the cold frontal
passage Friday morning, just after 12 for the city terminals.
For tonight, increasing S winds and LLWS. Winds will be strongest
from 05Z to 12Z, SSW-S winds G40-50kt coastal terminals, and G35-
40kt inland. Peak winds 50-55 kt possible, especially KISP/KGON.
LLWS with SW winds 65-75 kt at 2 kft AGL E of the NYC metros and 50-
60 kt for the NYC metros north/west.
Following the cold frontal passage Friday morning, NW G35-40kt
immediately behind the front, then G30-35kt through the early
afternoon and then decreasing further very late in the day.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
The greatest challenge/uncertainty will be during the next several
hours overnight as to how much of the winds aloft can mix down to
the surface. Lowering visibilities in any heavier rain along with
changing ceilings could result in changing flight categories between
IFR and MVFR.
.OUTLOOK FOR 0Z SATURDAY THROUGH TUESDAY...
.Friday night...VFR. NW G10-15ktG20kt during the evening, then
diminishing to 5 kts or less after midnight.
.Saturday...Cold fropa in the afternoon. Chance of a brief snow
shower with MVFR or lower cond. SW winds 10-15G20kt in the morning,
becoming W 15-25G30kt in the afternoon.
.Saturday night...VFR. NW winds 15-25G30-35kt in the evening,
diminishing to 10-15G20 kt after midnight.
.Sunday...VFR. W winds in the morning, becoming SW in the afternoon
with gusts 15 to 20 kt.
.Monday...VFR with SW winds.
.Tuesday...MVFR or lower with rain becoming likely. LLWS possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
As a LLJ strengthens ahead of approaching cold front overnight,
45-50 kt wind gusts are likely on ocean waters and eastern
nearshore waters after midnight through early Friday morning,
with gale conditions likely the remainder of the waters. Storm
conditions should quickly end from W to E in wake of cold
frontal passage early Friday morning, with gale conditions
gradually ending from W to E through early Fri afternoon. WNA
indicating seas building to 15 to 19 ft tonight into Fri AM,
which is quite reasonable.
Northwesterly flow subsides Friday afternoon with gale conditions
subsiding to small craft. High seas will remain into Friday evening
on the ocean, especially the eastern ocean. Seas will then continue
to subside to around 5 to 6 ft by Sat morning.
SCA conds expected on all waters by Sat afternoon ahead of a cold
frontal passage, then W-NW gales likely on the ocean late day Sat
into Sat night following fropa. NW gales may also be possible on the
non-ocean waters Sat evening. Quiet conds quickly return to all but
the ocean and ern waters Sunday morning, then to all waters by late
morning Sunday.
Minimal SCA conds in the form of hazardous seas are possible late
Sunday night into Mon morning as SW flow increases to near 20 kt.
SCA conditions may return by Wednesday afternoon into Wednesday
evening.
&&
.HYDROLOGY...
1/2" to 1" of rain is likely, locally 1" to 1 1/4" possible,
particularly across Interior and hill terrain, tonight into
early Friday. Most of this falling in a 3 to 6 hr period,
presenting a localized minor urban and poor drainage flooding
threat.
Will have to monitor for localized ice jam flooding potential
through Friday, possibly into Saturday, along our far interior
river/streams with mild temps, rainfall, and melt of limited
snowpack, allowing for increased water levels/streamflow and ice
break-up.
Finally, if higher end rainfall amounts are realized across
Hackensack/Passaic river basin of NE NJ (low probability), some
minor flooding of quick reacting small streams in this basin is
possible based on 3-6hr FFG around 1 to 1 1/2".
No additional hydrological impacts are expected into next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...High Wind Warning until 10 AM EST Friday for CTZ007-008-
010>012.
Wind Advisory until 10 AM EST Friday for CTZ005-006-009.
NY...High Wind Warning until 10 AM EST Friday for NYZ078>081-177-
179.
Wind Advisory until 10 AM EST Friday for NYZ067>075-176-178.
NJ...Wind Advisory until 10 AM EST Friday for NJZ002-004-006-
103>108.
MARINE...Storm Warning until 1 PM EST Friday for ANZ331-332-340-345-350-
353-355.
Gale Warning until 1 PM EST Friday for ANZ335-338.
&&
$$
SYNOPSIS...JC
NEAR TERM...JC/JE
SHORT TERM...JC
LONG TERM...DBR
AVIATION...JE
MARINE...JC
HYDROLOGY...JC
Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
656 PM EST Thu Feb 17 2022
.SYNOPSIS...
Crossing low pressure has brought rain and windy weather to the area
tonight. Snow shower potential returns for Saturday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Just some cosmetic changes to the evening update to fall more in
line with current trends and latest model guidance. Pops were
updated to better time the back edge of the precipitation shield.
Temperatures were modified with a blend of the latest hires model
guidance. Rest of the forecast in good shape.
Previous discussion...
The areal flood watch, wind advisory, and river flood warnings and
watches remain as is.
Flooding and high wind concerns should subside in the predawn of
Friday as the low pressure exits east and dry, cold air advances.
Any remnants of moisture from this system will change to snow after
midnight. Note, Hi-Res models (like the HRRR and NAM) are showing a
transition period of wintry mix before snow. However, with warm
conditions throughout the day it seems unlikely that road
temperatures will be affected by ice.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
Snow chances will be limited to the ridges late Friday morning due
to upsloping before subsiding as winds shift from the west/southwest
and high pressure builds.
An Arctic front will return snow showers to the region Saturday.
Expect highs 5 to 10 degrees under the averages. Snow showers may be
briefly intense given the wind field and a relatively deep mixing
layer through the dendritic growth zone.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Long range model ensembles indicate quiet, dry weather Sunday into
Monday over the Ohio River Valley under high pressure.
Precipitation may return to the region Tuesday into Wednesday as
warm, moist air returns to the region and a upper-level trough deeps
over the West Coast.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
MVFR and ptchy IFR in ra will continue as sfc low pres tracks NE
along a front. The low should move across Wrn PA overnight, pulling
the cdfnt through. MVFR cigs should continue in cold advection after
FROPA. A gradual improvement to VFR is expected Fri under building
high pres and dry advection. Cigs should then sct out by late
aftn/erly eve.
A llvl jet should result in llws this eve, before mixing and a tight
pressure gradient result in W wind gusts from 30-35kt. Wind should
gradually diminish through the day Fri as the pressure gradient
relaxes.
.Outlook...
The next restrictions will come with a reinforcing cdfnt on
Saturday, and sfc low pressure on Tue.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch through Friday morning for PAZ007>009-013>016-020.
Wind Advisory until 5 AM EST Friday for PAZ023-031-073>076.
OH...Flood Watch through Friday morning for OHZ039>041-048>050-057-058-
068.
Wind Advisory until 5 AM EST Friday for OHZ069.
WV...Flood Watch through Friday morning for WVZ001.
Wind Advisory until 5 AM EST Friday for WVZ004-012-021-509>514.
&&
$$