Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/25/20
AREA FORECAST DISCUSSION
National Weather Service Albany NY
947 PM EST Mon Feb 24 2020
.SYNOPSIS...
Clouds will increase, thicker and lower tonight ahead of
a cold front. Some spotty light rain or snow showers are possible
tomorrow with temperatures still running above normal. A weak warm
front will lift towards the region Tuesday night into Wednesday
associated with a complex storm system with more clouds and light
precipitation. A secondary low pressure system will move northeast
from near southern New Jersey Wednesday night, and then move
across the region on Thursday bring a widespread rain and snow
event.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 940 PM EST, quiet night continues across eastern NY with
temperatures in the 30s to low 40s. The latest radar imagery
does show some light returns but no precip has been observed at
the surface. Albany`s 00Z sounding shows a lot of dry air below
500 mb. Therefore, no changes were made to the near term
forecast at this time. Further details regarding the near term
forecast follow...
As of 640 PM EST, high level clouds continue to increase across
the area this evening as the next storm system approaches.
Earlier this afternoon, we saw some locations warm above 60
degrees, a feat we haven`t seen since mid January. So in terms
of the near term forecast, it remains on track outside of some
minor tweaks to the hourly temps.
Prev Disc...
As of 410 PM EST...The fair and tranquil weather should
continue into tonight. Above normal temps will cool rather
quickly with partly cloudy skies and light to calm winds. High
pressure will be drifting further offshore, as southwest flow
will continue in the mid to upper levels across the Northeast
ahead of an approaching cold front.
Temps should cool off quickly with the near ideal radiational
cooling conditions, and the dry atmosphere in place. However,
mid and high clouds will increase and slow the fall in temps.
We have mins tonight shortly before or just after midnight.
Temps will fall into the mid 20s to around 30F north of the
Mohawk Valley and Capital Region, and lower to mid 30s to the
south.
The latest 3-km HRRR and NAMnest keep the overnight period dry,
and with the lack of low-level moisture, this seems to fit a
dry overnight period.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Tomorrow...A lackluster cold front slowly descends south to
southeast across the region with weak low-level convergence and
lack of deep low-level moisture. The best chance of light rain
or light snow will be over the northern tier of the forecast
area. Some light sprinkles or light rain showers may also
impact south of the these areas more in the afternoon, as the
front dips southward. The 18Z NAM and 12Z GFS hint at this
scenario. We kept PoPs in the chance or slight chance category
with the lack of strong synoptic forcing. Highs will still run
above normal by close to 10 degrees, but much cooler than today
with mid 30s to lower 40s over the higher terrain, and mainly
mid 40s to around 50F over the lower elevations. Any light snow
accums over the mtns will be a dusting to a couple of tenths.
Tue Night...A short-wave in the southwest flow approaches the
region with the cold front trying to lift back north as a warm
front. The NAM/GFS model soundings continue to favor rain/snow
with perhaps some sleet over the southern Adirondacks, Lake
George Region into southern Vermont. We kept the highest PoPs
over the southern Adirondacks. Further south the boundary layer
should be warm enough for mainly rain. The pcpn looks light with
weak isentropic lift and convergence with the short-wave and
pseudo warm front. Lows will be similar to tonight with perhaps
some upper 30s over the mid Hudson Valley. Snow accumulations of
a half an inch to and inch may occur over the southern Dacks.
Wednesday...Cloudy and cool conditions persist, as low pressure
approaches from the OH Valley. Some over running light pcpn may
continue through the day. A secondary wave begins to form near
the NC/VA border based on the 12Z EC/GFS/Ensembles. A light rain
and snow mix is possible over the mtns north of the I-90
corridor with rain to the south. A stronger low-level jet
associated with the complex storm system approaches for Wed
night. Max temps will generally be in the mid 30s to mid 40s
across the forecast area with the coldest readings over the
northern mtns.
Wed night...Double barrel low pressure system impacts the region
with the secondary wave bringing a slug of Atlantic moisture.
An anomalous east to southeast LLJ will advect in the moisture
and enhance it across the region. The primary low will move
across the eastern Great Lakes Region with the secondary wave
moving from near southern NJ to somewhere between Albany and NYC
by Thu morning. The mid and upper level trough becomes
negatively tilted. Strong QG lift will allow for periods of
moderate to heavy pcpn. Downsloping will inhibit the pcpn
initially in the upper Hudson Valley, but the sfc winds will
turn to the north to northeast. The strong upper level dynamics
and dynamical cooling will allow for some moderate to heavy snow
over the mountains especially the southern Adirondacks, and
southern Greens where several inches are possible. The eastern
Catskills, and Berkshires could have a light accumulation. The
valleys should see mostly rain with perhaps a light wet snow
accumulation on the grassy areas. The exception may be the Glens
Falls/Upper Hudson Valley and the western Mohawk Valley area,
where 1-3" is possible. Some sleet could also mix in over the
higher terrain. We may need winter headlines for the northern
areas and we continued to highlight in the HWO. Lows will be in
the lower to mid 30s in the valleys, and mid 20s to lower 30s
over the mtns.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As the long term begins, energy will be diving into the upper
trough, helping to strengthen and set it up across the northeast
CONUS. This will result in ongoing precipitation throughout the day
Thursday with a mix of rain and snow. Snow will mainly be confined
to the higher elevations with mainly rain in the valleys. Thursday
night, the main surface low will lift north as the upper trough
becomes centered over the region. This should allow for the bulk of
the precipitation to lift north with the low center.
With favorable westerly flow, lake effect snow is expected to
set up Thursday night and potentially continue through Friday
night. Main area of concern will be across the southern
Adirondacks during this time frame. What is impressive is the
lack of ice on the lakes this time of year, so there will be
plenty of lake moisture to tap into for snow production. Stay
tuned to see if any winter weather headlines will be needed.
The upper trough finally begins to shift east on Saturday, bringing
an end to the lake effect snow. This will allow for a dry but chilly
weekend with highs in the 20s to low 30s Friday through Sunday.
Overnight lows in the single digits to upper teens.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Flying conditions will remain VFR for most if not all of the TAF
period. High clouds will thicken and lower this evening into
the overnight hours. A couple of light rain showers cannot be
ruled out after 15Z Tuesday, with better chances around 20Z.
Have accounted for shower chances with PROB30 groups for all
terminals.
Winds will become light and variable overnight, turning more out
of the north by Tuesday morning.
Outlook...
Tuesday Night: Moderate Operational Impact. Chance of RA...SN.
Wednesday: Moderate Operational Impact. Chance of RA...SN.
Wednesday Night: High Operational Impact. Definite RA...SN.
Thursday: Moderate Operational Impact. Likely SHRA.
Thursday Night to Saturday: No Operational Impact. NO SIG WX.
&&
.HYDROLOGY...
Above normal temperatures for late February will continue
through Wednesday, which could allow some ice on area waterways
to thaw, and snow to melt.
Light precipitation impacts the Hydro Service Area Tuesday into
Wednesday with little or no impact on the waterways.
A widespread precipitation event is likely Wednesday night into
Thursday, with rain turning to snow over higher terrain, and
rain with perhaps a little wet snow in the valleys north of
Interstate 90. Some areas could see around an inch of liquid
equivalent precipitation from Wednesday into Thursday, mostly
rain but some significant wet snow falling in the southern
Adirondacks, portions of the Lake George Region and the southern
Green Mountains. Some within bank rises are possible on rivers,
but flooding is not anticipated.
Temperatures will cool back down for the end of the week. At
this time, significant hydrological issues are not expected.
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...Wasula
NEAR TERM...JLV/Wasula
SHORT TERM...Wasula
LONG TERM...JLV
AVIATION...Thompson/JLV
HYDROLOGY...NAS/Wasula
Area Forecast Discussion
National Weather Service Columbia SC
705 PM EST Mon Feb 24 2020
.SYNOPSIS...
A warm front south of the forecast area will lift northward and
through the area late tonight and early Tuesday ahead of an
approaching cold front. The cold front will be in the area
Wednesday. The deepest moisture will occur ahead of the warm
front tonight and early Tuesday morning. Above normal
temperatures will occur behind the warm front Tuesday and
Wednesday. Below normal temperatures will occur behind the cold
front Thursday and during the rest of the week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Rain has temporarily diminished across the area as mid level
short wave trough moves to the northeast. However, radar
indicating widespread showers back in central Ga moving
northeast. This is associated with the warm front which will
move into the region overnight. Models suggest relatively strong
moisture flux and isentropic lift along with some weak short
wave energy as upper trough and surface low move northeast into
the Ohio Valley. The models suggest locally heavy rain possible
mainly between 06z and 09z with qpf max across the Piedmont and
west Midlands. So categorical pops later this evening as rain
spreads east- northeast across the area. QPF 0.5 to 1.5 inches
across the area with precipitable water increase to nearly 200
percent of normal supported by 40-50 kt low level jet.
Isolated minor flooding remains a possibility due to the
saturated ground from weeks of above normal rainfall but the
highest rain totals are expected in the Upstate/Piedmont. QPF
appears to remain below Flash Flood guidance especially in the
east Midlands. It should be noted that a couple of the hi-res
models including latest runs of the HRRR indicate possible
convection along the Gulf Coast tonight which may impede
moisture advection northward and further lower rainfall totals
expected.
While surface instability is nil as the area remains north of a
warm front, cannot totally rule out an isolated elevated
thunderstorm and severe weather is not expected. Temperatures
overnight will gradually rise as the warm front approaches and
lifts north through the area with overnight lows likely
occurring early in the night.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
A warm front will lift north of the area early Tuesday morning
while a cold front approaches from the west. The cold front will
shift east through the area on Wednesday. The deepest moisture
will push eastward on Tuesday with the best chance for rain
east. The high resolution models show the best coverage along
the coast. Lowered pops some Tuesday and Tuesday night. Models
indicate LI values of -1 to -4 on Tuesday, but believe the
chance for thunder is too low to include mention in forecast
given the shallow moisture and weak convergence ahead of the
cold front. Model QPF is light generally showing a tenth of an
inch or less for Tuesday. Chance pops still appear reasonable
for Wednesday with the deepest moisture still east of the area
and weak convergence along the front. Above normal temperatures
are forecast Tuesday and Wednesday ahead of the front. It will
be breezy on Wednesday with gusts to of 20 to 25 mph, but expect
to stay just below Lake Wind Advisory criteria.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
High pressure over the western Gulf of Mexico will ridge into the
region Thursday and Friday. Cooler and drier air will filter into
the area with precipitable water values dropping down to less than a
quarter inch. An upper disturbance and reinforcing cold front will
pass through the region on Saturday, but moisture appears limited.
Pops less than 15 still appear reasonable. Sunday appears dry with
surface high pressure in place over the region. High pressure will
shift early next week with moisture deepening. Below normal highs in
the lower to middle 50s are expected through Sunday. Temperatures
will moderate to around 60 on Monday with flow becoming
southerly.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
IFR/LIFR conditions through most tonight with improvement to VFR
by Tuesday afternoon.
Most terminals begin the TAF period in IFR conditions with CIGs
below 1000 feet. CIGs are expected to drop further to LIFR as
heavier rain moves in later tonight. This will also cause VSBYs
to drop to IFR at all terminals. Rain will continue through the
night and begin to taper off Tuesday morning which will lead to
increased VSBYs, although CIGs may be a bit slower to recover.
Dry air will continue to filter in Tuesday leading to
improvements to MVFR conditions by late morning and then VFR
conditions during the afternoon.
Winds will be generally shifting from southerly to westerly
tonight into tomorrow. A SW low level jet will move over the
area tonight leading to LLWS criteria. Winds remain between 5
and 10 knots through tomorrow morning at the surface before
increasing tomorrow afternoon. As this low level jet mixes out
tomorrow, gusts during the afternoon are expected to be between
15 and 20 knots.
EXTENDED AVIATION OUTLOOK...Restrictions remain possible
associated with this system through Wednesday when a cold front
moves through the region.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
501 PM CST Mon Feb 24 2020
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Tuesday)
Issued at 1213 PM CST Mon Feb 24 2020
A busy short term forecast with an upper level weather pattern out
of the northwest bringing in a stout shortwave through the
afternoon and evening and then a closed low moving from northwest
Nebraska into central Kansas during the day Tuesday.
Tonight on ongoing shortwave will move from northeast Colorado
into western Kansas. Radar as of the time of this discussion is
showing an area of rain and snow in northeast Colorado and strong
winds out of the northwest gusting to 40 mph. This area of
precipitation will move into Kansas by mid afternoon and continue
eastward through the evening. Precipitation with this line should
stay mainly rain...although with short term models hinting the 850
mb temps hovering around 0 to -1(C) as the line progresses through
can`t rule out either some graupel or a snowflake mixing in.
Winds in and behind the line could gust briefly to over 40 mph
especially for areas along and west of highway 83. Precipitation
should wind down by midnight with the exception of the line
lagging in north central Kansas. This line will be the focus of
tomorrows precipitation discussion. Lows tonight should fall into
the 20s and 30s.
Tuesday a closed 500 mb and 700 mb low moves from northwest
Nebraska into central Kansas. By afternoon the position of the low
looks to be around Salina which will set the stage for strong cold
air advection, increasing winds (both at 850 mb and the surface)
and bands of snow developing from late morning through the
afternoon and early evening. Snowfall totals at this point should
be light for most of the region...however areas along the I-70
corridor have the best shot at seeing accumulations over an inch
combining with strong winds. Impacts look likely for the I-70
corridor and the possibility of a winter headline (winter wx
advisory at least) will be looked into later this afternoon.
As the snow bands move south the CAM models are all hinting at the
possibility of snow squalls. 12Z HRRR has a very aggressive snow
squall moving south and west from the I-70 corridor in the late
morning...towards Elkhart by afternoon. This squall should it
develop combining with winds 25-40 mph will certainly produce
blowing snow and reduced visibility. Snowfall totals will be iffy
as it looks like it should be a fast moving line...however there
is indications of more bands of light snow developing behind the
line which would continue the visibility impacts. At this point
around 1/2 inch of snow seems to be a good bet for accumulations
however these amounts could increase as the evolution of the storm
system takes shape. In any case prepare for some winter impacts
in the afternoon across much of southwest Kansas with the
possibility of an upgrade if blizzard like conditions present
themselves as the evolution of the storm becomes more known in the
afternoon and early evening.
Highs on Tuesday will range from the mid 30s in the north to near
40 in the south.
.LONG TERM...(Tuesday night through Monday)
Issued at 153 PM CST Mon Feb 24 2020
Quiet weather upcoming in the long term. Wednesday the upper low
moves east out of the region with an area of high pressure sliding
in. The cold air should stay in place most of the day before
westerly winds start to slowly push the colder air out. Highs
should be in the upper 30s to low 40s.
Thursday another cold front looks to move through the region as
another upper level trough moves through the central and northern
plains...highs will be in the upper 40s to low 50s.
Friday through the weekend an upper level ridge in the rockies
moves into the central plains with gradually warming temperatures.
50s on Friday and 60s look to be a good bet at this point for both
Saturday and Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 432 PM CST Mon Feb 24 2020
Current VFR conditions for all locations ahead of the frontal
boundary that will push across the CWA in the beginning portions
of this TAF period. Winds will turn out of the northwest around
15kts with rain showers associated with it already depicted on
radar currently through the western portions of the CWA. Winds
will slowly increase overnight as the rain showers will come to an
end by 04-06Z except for lingering showers for the HYS site. Gusts
up to 25kts through mid morning around 15Z before good mixing of
the boundary layer to the surface pushing gusts up to 30-35kts. On
the backside of the upper level system, expect light snow to
develop across the occlusion after 21Z through the end of the
period with the higher amounts around the HYS area. Blowing snow
will also be prevalent with the gusty northwest winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 28 35 20 39 / 60 70 40 0
GCK 26 34 19 41 / 30 70 30 0
EHA 26 37 18 45 / 0 70 30 0
LBL 26 37 19 42 / 20 50 30 0
HYS 28 33 19 37 / 70 80 40 0
P28 32 40 23 41 / 50 60 40 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to 6 PM CST
Tuesday for KSZ030-031-044>046.
&&
$$
SHORT TERM...Tatro
LONG TERM...Tatro
AVIATION...Lowe
Area Forecast Discussion
National Weather Service Grand Rapids MI
904 PM EST Mon Feb 24 2020
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 258 PM EST Mon Feb 24 2020
- First round of light precipitation tonight
- Steady snow arrives Tuesday afternoon into Wednesday with 4 to
7 inches of snow expected by Wednesday evening
- Lake effect snow showers on Thursday into the weekend
&&
.UPDATE...
Issued at 905 PM EST Mon Feb 24 2020
I have adjusted the POP and QPF for the now through overnight
period to concentrate the precipitation in the I-69 area west
alone I-94. Looking at the IR satellite loops and the water vapor
image loops, it can be clearly seen the upper level system helping
to create the precipitation over our southern and eastern CWA is
already shearing out. Earlier this evening there was a very clear
baroclinic leaf cloud((near I-80) that merged with the main
precipitation producing cloud band closer to I-94. That did
enhance the precipitation near I-94 and I-69 an hour or so ago.
This precipitation will continue to lift more east than north,
mostly being east of our CWA by 1 am this morning.
It will get cold enough for the precipitation to mix with and
change to snow before it moves out but surface temperatures will
remain above freezing and precipitation rates will be on the oder
of .01 > 0.02" /hr so I do not see adding up to much of anything
to create impacts. Also, even after the precipitation ends the
surface temperatures will not fall enough to cause to many issues
with ice on roads for the morning travel time.
I also adjusted the POP for Tuesday during the day. From the
latest model runs I do not see much if any precipitation during
the day time hours of Tuesday.
It seems to this forecaster that the storm on Wed may be father to
the east as it now seems the upper wave on the southern stream
will take a little longer to phase with the northern stream wave.
We will have to see how this plays out. I do not plan to change
any headlines.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 258 PM EST Mon Feb 24 2020
- First round of light precipitation tonight
It will take a while but the impressive dry wedge seen in the
sounding data will be eroded this evening and precip will move
north, reaching the central forecast area by 06Z. Model soundings
show that precip type should go from a mix over to snow later in
the evening as wet bulb zero heights fall through a combination of
evaporative cooling and low level cold advection.
- Steady snow arrives Tuesday afternoon into Wednesday with 4 to
7 inches of snow expected by Wednesday evening
A sharp, narrow northern stream shortwave trough is the main
player and its amplitude and timing of its phasing with the
southern stream has been the main forecast problem that past
couple days. Fortunately, the 12Z GFS fell in line with other
models that have been consistently showing a further south axis of
the heavier snow, so we are fairly confident now in the location
and amount of snow, with the heaviest amounts coming on Wednesday
south of a line from Holland to Lansing.
Mesoscale banding in area of stronger f-gen is expected across
the southeast half of the forecast area Tuesday night and
Wednesday.
We issued a watch, though we expect snow amounts and expected
impacts should be more in line with an advisory than a warning.
Travel could be difficult as temperatures drop on Wednesday and
untreated roads become snow covered and icy.
- Lake effect snow showers on Thursday into the weekend
We expect a lull Wednesday night as the low pulls away along with
the f-gen forcing and is replaced by shortwave ridging. This is
followed by another trough with cyclonic flow and inversion
heights that would allow lake effect snow showers to form and move
inland in west northwest flow for Thursday into Saturday with some
accumulations possible.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 649 PM EST Mon Feb 24 2020
The low clouds are struggling to fight the dry air in place over
SW Lower Michigan at 23z this evening. My spin is the
precipitation will struggle to impact the TAF sites tonight and
while I did actually bring MVFR cigs/vis into most of our TAF (NOT
MKG OR GRR) I am really questioning it.
The MVFR cigs have only made it to the Michigan/Indiana and
Michigan Ohio board at 23z and most of the radar echoes near I-94
are not making it to the ground. The 22z run of the HRRR shows JXN
getting around about a tenth of an inch of precipitation tonight.
with less than .05" at LAN,AZO and BTL. At LAN the cig goes down
to 2500 ft for 4 hours between 05z and 09z then goes back up to
5000 ft and stays there through 16z. The cigs below 3000 ft on the
HRRR only show up, even at JXN, from 04z till 10z, then back to
VFR. It may well turn out mostly VFR cigs through most of
Wednesday at most of our TAF sites. I would think the lowest
conditions will be a JXN between 04z and 10z as the precipitation
from the shearing out system impacts that area.
&&
.MARINE...
Issued at 258 PM EST Mon Feb 24 2020
Winds and waves will increase on Tuesday and north gales are
possible by Wednesday afternoon.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Storm Watch from Tuesday afternoon through Wednesday
evening for MIZ043>046-050>052-056>059-064>067-071>074.
LM...None.
&&
$$
UPDATE...WDM
SYNOPSIS...Ostuno
DISCUSSION...Ostuno
AVIATION...WDM
MARINE...Ostuno
Area Forecast Discussion
National Weather Service Huntsville AL
803 PM CST Mon Feb 24 2020
.NEAR TERM...(Tonight)
Issued at 803 PM CST Mon Feb 24 2020
The 00Z 300 mb analysis shows a 130-140kt jet streak diverging over
the middle TN valley this evening. A narrow dry slot has poked
through northern MS into middle TN and KY, while the larger mass of
rain has shifted into south AL/GA/Carolinas. Showers have been more
scattered in between over north AL and southern middle TN this
evening. Low clouds and patchy drizzle are also occurring. At the
surface, low pressure over southeast MO was slightly occluded now,
with a warm front draped southeast through central AL into south GA.
A narrow warm sector has poked into southwest TN ahead of the cold
front that is now just east of the MS River. A few showers continue
along the cold front, but the OHX and BMX soundings show little to no
CAPE to work with. In fact, the BMX sounding showed a warm layer
between 8-7h which should negate thunderstorm potential further. The
HRRR suggests a continued reduction in coverage of showers as this
line progresses east overnight. Have removed thunderstorms from the
forecast, but maintained the showers albeit with decreasing PoPs
going east later tonight. All rain should exit most areas before
09-10Z with a few lingering showers in the far east just before
sunrise.
.SHORT TERM...(Tuesday through Wednesday)
Issued at 310 PM CST Mon Feb 24 2020
Rain will come to an end early Tuesday morning, but expect low clouds
to remain through the morning, before some breaks develop later in
the day. With deep SW flow quickly developing ahead of the next
upper-low developing across KS/OK, do not expect much in the way of
air mass modification. Expect temperatures to surge into the lower
60s by the afternoon -- the last time our highs will be above normal
for the next 6-7 days. As the aforementioned upper-low shifts into
the Ohio Valley, a stronger, arctic front will dive through the
Tennessee Valley Tuesday night into Wednesday. Deep layer moisture
will be a little more limited ahead of this system, so expect shower
activity to be more scattered in nature and QPF a bit lighter. Colder
and drier will filter in by Wednesday afternoon, cutting off
precipitation by late in the day.
.LONG TERM...(Wednesday night through Sunday)
Issued at 310 PM CST Mon Feb 24 2020
Good arctic air being advected into the area around the backside of
the strong surface low over the eastern Great Lakes region on
Thursday afternoon will keep temperatures in the upper 30s to lower
40s, despite sunshine. Some 925 mb temperature progs suggest highs
could be a bit lower only reaching the 30s across the area. Expect
cloud cover to move into the area Thursday evening. Models keep dry
air in place near the surface late Thursday night into Friday morning
in much of the boundary layer. Also, models keep the area on the far
on the edge of the forcing swinging east from Missouri into eastern
Kentucky/Tennessee. These factors have led me to leave any
precipitation out of the forecast with this system. If this forcing
does move further south than currently forecast, then some
precipitation (partially in the form of flurries or light snow) may
need to be added to the forecast late Thursday night into Friday
morning. However enough cloud cover should keep temperatures from
tanking, keeping them in the upper 20s to lower 30s overnight.
Think we will see a break in the cloud cover during the day on
Friday. This and a bit warmer start to the morning should help
temperatures climb a bit higher. Right now, highs around 40 degrees
in higher elevations and lower to mid 40s elsewhere look reasonable.
Models are trending more towards a second stronger shortwave moving
southeast from Missouri into central Tennessee and northern Alabama
Friday evening into Saturday morning. Though snowfall amounts and
accumulations vary from model to model at this time, it is looking
like we could see a period of light to moderate snowfall shortly
after midnight on Friday into early Saturday morning. Actual air
temperatures (and possibly ground temperatures) will help to keep
accumulations very light. The exception to this may be in the higher
elevations above 1000 feet. There, these factor may not limit
accumulation as much given a weak temperature lapse rate just above
the surface. For now, though only including a trace to one quarter of
an inch of snowfall accumulation by early Saturday morning. For now
only included a 20 to 30 percent chance of this precipitation.
However, this may need to be raised if current trends hold in future
guidance. A few models do suggest that between one half of a inch to
one inch is plausible in our higher elevations, but this is too
uncertain at this time to include. Late Thursday night through Friday
morning will need to be monitored closely for possible increases in
snowfall.
Forecast sounding and RH fields suggest a clearing late Saturday
morning. This should allow temperatures to rebound well above
freezing into the 40 to 50 degree range in most areas later in the
afternoon. Saturday looks to be one more cold night, with northwest
flow aloft continuing and lows reaching the mid to upper 20s.
The good news is that by Sunday, the pattern changes as the large
area of low pressure previously hung up over the northeastern CONUS
finally moves east and well away from the northeastern seaboard.
Zonal flow aloft quickly builds into the area behind it on Sunday.
Highs should rebound back into the lower to mid 50s. As a result much
warmer and more moist air will be advected back into the region, as
a front builds up it strength over the Midwestern CONUS. This could
bring rainfall back to the area early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 451 PM CST Mon Feb 24 2020
A large area of showers has shifted east of the KHSV area leaving a
temporary break thru the next 1-2 hours. IFR ceilings below 010agl
will persist with scattered SHRA redeveloping after 00Z. At times,
vsbys will drop to ~2SM with ceilings below 005agl (LIFR) this
evening. There remains a slight chance of a thunderstorm, but have
left out of the TAFS due to low probability. A cold front will shift
winds to the southwest after 05-06Z. This may temporarily allow
ceilings to scatter at KMSL from 07-12Z before IFR ceilings return by
15Z. At KHSV, will remain pessimistic with ceilings of 010-015agl
(MVFR) remaining MVFR after 07Z. At this time, fog is not expected
unless more widespread clearing can take place.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...17
SHORT TERM...AMP.24
LONG TERM...KTW
AVIATION...17
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Marquette MI
642 PM EST Mon Feb 24 2020
.SHORT TERM...(This evening through Tuesday)
Issued at 356 PM EST MON FEB 24 2020
Water vapor imagery and RAP analysis show a trof over central N
America with 2 branches of flow evident. The southern branch
features one shortwave over southern MO with a second dropping se
across the Rockies. To the n, a shortwave is moving into far
northern Ontario. Btwn these features, it`s been a quiet day across
the fcst area with much more sun than expected, except over the e
where bkn to ovc stratocu has developed with a definite spring-time
look (more sun closer to Lake Superior where it`s slightly more
stable from the marine layer and more cloud cover inland where there
is more instability from daytime heating). These clouds over the e
are also downstream from a low-level moisture band evident by cloud
cover streaking sse across northern Ontario to central Lake
Superior. With the sun, temps have risen into the lwr 40s
today across a good portion of the fcst area.
Diurnal heating and resulting increased mixed layer today has helped
to mix out at least some of the upstream moisture to the n of Lake
Superior, and this has some implications for the potential of any
-fzdz/flurries tonight under low-level winds veering from nw to ne.
Fcst soundings still indicate increasing low-level moisture tonight
due to added moisture from Lake Superior as 850mb temps ease down to
-8 to -10C during the night and due to nocturnal cooling of the
boundary layer. There is a fair amount of variation among the models
on whether temps in the moist layer will be low enough to support
ice nucleation (typically -10C is used as threshold). So, ptype
could be -shsn or -fzdz if pcpn develops. Since air mass is not cold
enough to support lake effect pcpn, pcpn would likely only be
upslope generated. For now, plan is to push back timing of any
potential pcpn to late tonight when low-level moisture will be
better. Will also confine pcpn mention to areas that have a more
direct upslope wind component over the far w and in Marquette/Baraga
Counties. Will also continue to mention ptype as -shsn/-fzdz though
given the mixing that has occurred today, not sure there will be
sufficient low-level saturation to yield -fzdz. Expect min temps
tonight in the 20s, but areas that have less clouds thru the night
will slip into the teens.
Slight cooling continues on Tue, but 850mb temps only fall roughly
another 1C. Will maintain mainly schc pops in the same areas as late
tonight. The slight cooling should tend to favor ptype becoming
mainly -shsn with time, if any pcpn does occur. Otherwise, expect
more cloud cover on Tue under the added moisture off the lake. Any
locations downwind of the lake that start the day with some sunshine
should see rapid stratocu expansion during the morning. Exception to
the cloud cover will be over the eastern fcst area as shorter fetch
under nne wind may cut down on low-level moisture off the lake to
diminish stratocu coverage. Will be cooler on Tue with highs in the
upper 20s to mid 30s, warmest south central.
.LONG TERM...(Tuesday night through Monday)
Issued at 334 PM EST MON FEB 24 2020
Previously it`s been said that the models are struggling with the
track and strength of the upcoming cross-country storm system. But
that`s not really fair to the rest of the models that aren`t the GFS;
the GFS has by far struggled to grasp the evolution more than any
other major modeling center`s output. Finally today it has settled
into the guidance envelope with the rest of the guidance in tracking
the main low well south of the area - so far so that even Milwaukee
is on the northern fringe of system snow now. The result for us up
here in the U.P. is no system snow is expected at all anywhere; any
snow we do see this week will be entirely lake-effect. It also
reduces the chance for significant NE flow upslope/lake enhanced
snow, instead shifting focus to the more traditional NW flow LES
belts, since we`ll be farther removed from the cyclonic flow around
the main low. The exception to that trend still looks like Tuesday
night into early Wednesday when there could still be a period of Ne
flow LES. The GFS is deeper with moisture and would support a couple
to maybe several inches - but again given its performance lately
have decided to stick with the NAM which depicts weaker lift in the
low levels and thus results in a little less snow. Still, some
scattered snow showers amounting to an inch or two is certainly
possible in this time frame.
Then comes the transition to NW flow LES Wed night through Friday.
This is when the GFS, EC, and other models remain in good agreement
about a secondary mid-level short wave merging into the upper level
low late Wednesday and shoving Arctic air southward over Lake
Superior. The combination of 850 mb temps in the -17 to -20 C range
and saturation to, at a minimum, 700 mb, should support plenty of
LES for the N to NW wind snow belts, with the heaviest snows
occurring late Wed night through Thurs night. The new version of the
NBM seems to struggle with lake-effect POPs compared to the previous
version, so needed to significantly increase POPs (to likely or in
some areas categorical) for this time frame. Now that this event is
getting a closer, we can talk a little bit about potential
accumulations. All in all this may end up just being a run of the
mill lake-effect event, except longer duration that some. Several
inches of fluffy snow is likely in the NW wind snow belts, but over
about a 48-hour period which will reduce the overall impact. Still,
along with some wind and with this fresh snow falling on top of the
now dense and smooth old snow, blowing snow will become a concern,
especially by Thursday.
This lake-effect snow could linger over the east as late as early
Saturday morning, but with diminishing intensity as drier air
filters in aloft ahead of ridging that will be building into the
Upper Great Lakes for the weekend. Speaking of that ridging, the
weekend still looks dry with temps warming back to near normal.
There are some indications that another storm system could be
brewing for early next week, but not going to cry wolf over that
this far out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 633 PM EST MON FEB 24 2020
This evening, expect lowering cigs with all terminals becoming
MVFR by early overnight, beginning first at KSAW, followed by
KCMX and KIWD. MVFR cigs are then likely to persist into Tue with
maybe some light lake effect snow showers or flurries developing.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 356 PM EST MON FEB 24 2020
Expect winds mostly blo 20kt across Lake Superior tonight. As low
pres slowly lifts across the Ohio Valley, Lower Great Lakes and into
Quebec Tue thru Thu, northerly winds will gradually increase,
reaching 20-30kt later Wed thru Thu and lingering into Fri. Over the
east half of Lake Superior, n to nw gales to 35kt are possible
Thu/Fri. Winds will then diminish from w to e in response to high
pres ridge arriving over the Upper Lakes on Sat.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...RJC
AVIATION...Voss
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Norman OK
404 PM CST Mon Feb 24 2020
...New SHORT TERM, LONG TERM...
.SHORT TERM...
(This evening through Tuesday)
Issued at 320 PM CST Mon Feb 24 2020
Cloud cover and patchy drizzle will continue to erode from west to
east as storm system departs. However, additional cloud cover and
precipitation influenced from incoming s/wv trough and associated
cold front will spread into the region from western Kansas and
southeast Colorado this evening and overnight. Steep lapse rates
with quite cold temperatures aloft should allow for efficient rain
shower production, but little in the way of elevated instability to
support charge separation and thunder prospects. All models have
become more aggressive with potential for rain this evening and
overnight, especially across western and northern portions of
Oklahoma. With the anomalously cold temperatures aloft, we will
mention a rain/snow mix across northwest Oklahoma for a short time
before precip ends late this evening. By daybreak/tomorrow morning,
precipitation should be moving out of north-central Oklahoma if
there is any left at all. As upper trough moves across Kansas
tomorrow, reinforcing surge of colder air will move into the region
Tuesday afternoon and evening. Precipitation Tuesday afternoon will
initially fall as rain across northern parts of Oklahoma, but
transition to snow Tuesday evening and spread southward. At this
time, it appears any snowfall amounts will be light.
&&
.LONG TERM...
(Tuesday night through next Sunday)
Issued at 320 PM CST Mon Feb 24 2020
The focus for this period has been the developing upper level
trough over Montana and the potential for snow over north/central
Oklahoma with subfreezing temperatures at the surface Tuesday
night.
As of 21Z Monday, latest water vapor imagery and and RAP 500MB
heights show this trough oriented from eastern Montana - western
South Dakota - western Nebraska. The trough digs southeastward
over KS, bringing -30 deg C temperatures at 500mb and a reinforcing
cold front into Oklahoma Tuesday night. Models suggest strong lift
within the saturated dendritic growth zone associated with the
surge of arctic air and frontogenesis near the 850mb level
generating at least some wet snow from 00Z to 12Z Wednesday
across northern and central Oklahoma. Models are in good agreement
that these areas will see at least snow flurries to light snow
Tuesday night. The GFS is the fastest with the progression of the
upper low, with the NAM a bit slower, and the ECMWF the slowest.
The GFS has also trended farther south, more in agreement with the
ECMWF, and both of these models are more moist with the 12Z run
compared to its previous run. Whereas, the NAM has indicated
sufficient moisture over the past few runs. Therefore, confidence
is increasing that portions of north and central Oklahoma will see
light snow overnight Tuesday. Very Light accumulations of 0.1
inches over central Oklahoma to possibly 0.5 inches over north
Oklahoma are possible. Wednesday will be windy and cold with highs
in the 40s.
A nice warming trend is then expected beginning Thursday with
temperatures in the 60s by the weekend. Areas of southwest
Oklahoma and western north Texas are forecast to reach the low to
mid 70s on Sunday due to strong warm air advection and downslope
flow. Long term guidance suggests a chance for showers and
thunderstorms next Sunday.
Thompson
&&
.AVIATION...
(18Z TAFS)
Issued at 1114 AM CST Mon Feb 24 2020
Primarily MVFR conditions most terminals through 00Z with some
IFR conditions initially central and north-central Oklahoma. VFR
conditions expected primarily after 03Z. Upper trough will move
over region tonight and yield another band of MVFR cigs with
perhaps some light precipitation. Gusty northerly winds will
subside toward and after 00Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 38 50 28 42 / 10 10 30 10
Hobart OK 35 50 27 46 / 30 10 20 0
Wichita Falls TX 41 56 31 47 / 20 0 10 0
Gage OK 30 43 22 43 / 50 30 30 0
Ponca City OK 34 46 27 40 / 30 40 40 0
Durant OK 40 56 33 46 / 10 0 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...11
LONG TERM....01
AVIATION...11
Area Forecast Discussion
National Weather Service Pueblo CO
311 PM MST Mon Feb 24 2020
.SHORT TERM...(This evening through Tuesday)
Issued at 310 PM MST Mon Feb 24 2020
...Strong short wave will drop down across W KS tomorrow bringing
very cold wind chills tomorrow and possibly snow to the eastern
plains...
Currently...
Initial cold front has moved through the region. This system is
still producing areas of precip over the far eastern plains at 2
PM. More importantly, this system is producing strong winds across
all of the region along with some patchy blowing dust over parts of
the San Luis Valley (SLV). Temperatures were relatively mild, with
readings in the 40s to around 50s across most of the plains and SLV,
however readings were in the 30s and 40s across EL Paso county.
Mountains were quite cold with readings below zero at mtn top,
indicating the very cold air aloft.
The main concern during this forecast period is very cold wind
chills tonight and tomorrow. Another stronger cold front will move
down the plains later tonight as a strong shortwave drops southeast
across the NE panhandle and into far western KS. This scenario is
somewhat troubling as this is going to bring quite a bit of lift
over the eastern plains tomorrow along with cold air and the
increasing likelihood of snow. Since the winds are going to pick up
relatively early tomorrow morning wind chill values ranging between
plus 5 and negative 5 will be widespread tomorrow morning across the
plains, with values below zero in the valleys and mtns. Actual wind
values will likely be in the 20 mph range across El Paso county at
7:00 AM with winds of 10 to 20 mph elsewhere at the same time. These
winds combined with ambient temps in the teens will cause the very
cold wind chill values discussed above.
Additionally, the winds are only going to increase during the day
tomorrow, with sustained winds in the 25 to 35 mph range with gusts
to 50 mph likely. Ambient temps are only going to max out into the
lower 30s across most of the plains, so wind chills during the
afternoon are going to be in the teens and 20s.
As for snow, the models have been showing a troubling trend of
pushing the closed mid level low farther and farther west with each
model run (see the 18 UTC run of the 36 hour run of the HRRR for
existence). This will place the eastern plains in a more favorable
area of upward lift, and this will allow for some snow to develop
tomorrow. I have increased the pops over the plains to 30-60% most
areas, with the far eastern plains and northeast EL Paso county
seeing the higher amounts. This trend will have to be watched very
carefully by incoming shift, and winter weather highlights may be
needed. It is not out of the question that a period of intense
snowfall may occur over the plains tomorrow as the short wave moves
across during the midday time period. /Hodanish
.LONG TERM...(Tuesday night through Monday)
Issued at 310 PM MST Mon Feb 24 2020
Once we get through this next mid-level trough, late Tuesday night,
ridging takes over for much of the longterm period which is good for
the snow weary residents of southern Colorado. The pattern looks
rather boring though...
Tuesday night...Lingering mid-level troughing will swing through
providing enough lift to get some instability snow showers
continuing, across the eastern plains. Showers should quickly taper
off closer to midnight but leave very cold overnight lows in it`s
wake. Expecting low-teens across the plains, single digits along the
Front Range and southern I-25 corridor, near zero in th SLV and
negatives in the San Juans. With a little bit of wind, less than 10
MPH, it`ll feel at least 5-10 degrees colder.
Wednesday - Saturday...Expecting a dry pattern with moderating
temperatures, climbing back to seasonal averages by Thursday and
then several degrees above average heading into the weekend. There
could be a brief period of elevated fire weather conditions on
Thursday with a stronger north-northwest wind and warming daytime
temperatures. RH values are currently expected to drop into the
upper-teens across the plains Thursday afternoon. After this period,
the winds look to really decouple and turn more towards the south-
southwest.
Sunday...Mid-level ridging moves out and flattens some allowing
deeper west coast troughing to move back towards the Four Corners
region. We start to see an increase in rain/snow activity later on
Sunday, so unfortunately our string of milder and settled weather
looks to come to an end. There is still quite a bit of uncertainty
in the track of this next mid-level lobe/closed low pressure as it
moves across south of our region. This could be another warm system
with the better snows staying in the high country as the snow level
may be too high until we move into the overnight periods. Still lots
to chew on at this point.
Heav
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 310 PM MST Mon Feb 24 2020
Winds will be the issue during this fcst period. Strong winds will
continue this afternoon and early evening with dry conditions
anticipated at the 3 taf sites (KPUB, KALS and KCOS). Tonight the
winds will decrease but will begin to pick up relatively early
tomorrow morning and once again become strong from the north. It
should remain dry at KPUB and KALS tomorrow but there may be periods
of snow at KCOS, especially during the afternoon tomorrow.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM MST Tuesday for COZ058>060.
&&
$$
SHORT TERM...HODANISH
LONG TERM...HEAVENER
AVIATION...HODANISH
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
422 PM MST Mon Feb 24 2020
.UPDATE...
Issued at 314 PM MST Mon Feb 24 2020
Snowfall reports of 7 to 8 inches near Hulett, 2 inches in Colony,
and 4 inches in Belle Fourche have showed that the snow has
accumulated more quickly than originally expected. Current
snowfall forecast still looks on track, but that snow added to
what has already fallen will place a few more zones in warning
criteria. Considering this, decided to include the southern Meade
County plains in the warning as well, with that expected band of
upslope snow later tonight. Thinking the only other thing to watch
will be whether the Rapid City zone needs to be upgraded to a
warning, but will leave as an advisory for now.
&&
.DISCUSSION...(This Evening Through Monday)
Issued at 149 PM MST Mon Feb 24 2020
Upper wave continues to push into the northern plains,
with the surface low currently over southwestern SD. This
morning, a band of snow developed across northeastern WY, and
upslope snow began over the northern Hills. Currently, radar
depicts snow over far northeastern WY and much of western SD,
showing heaviest precip over the northern Hills and also around
the Hot Springs area. Northwest winds increased to 25 to 35 mph
behind the low, with some gusts around 40 mph. This has created
some blowing snow and reduced visibility.
Not much of a break in snowfall is expected for the area anymore.
The track of the low now keeps somewhat persistent snowfall over
western SD through Tuesday morning, although parts of northeastern
WY may have a brief reprieve. Latest Canadian/Euro/GFS ensembles are
consistent with 3 to 5 inches across the plains, with some places
potentially reaching 6 inches of snow. The most significant snow is
still expected across the northern Black Hills/foothills region,
where saturated profiles with high omega in the dendritic growth
zone, along with froude numbers, indicate upslope enhancement
continuing fairly steadily until Tuesday afternoon, when drier air
starts moving in.
As winds shift to the northeast tonight, the upslope enhancement
will shift over the northeastern Hills/foothills. Parts of the
southern Meade County plains closest to the Hills may receive
some higher amounts, but overall the advisory should be sufficient
for that zone. Snow for the Rapid City area will be tricky, as it
will depend greatly on where upslope enhancement occurs.
Ensembles continue to show only 2-3 inches of snow, as do the
HRRR and RAP. WPC`s QPF suggests 6-8 inches might be possible, and
a few hi-res models are higher yet. Froude number, along with
lack of inversion in the soundings, suggest that the upslope enhancement
may produce more snowfall over the central Black Hills, rather
than the Rapid City area. Have increased snow in the central Hills
and added that zone to the warning. With majority of models
showing advisory criteria, will leave the advisory as is for Rapid
City; however, later shifts may need to upgrade. If anywhere in
the Rapid City zone were to receive heavier snow, it would be the
northern part.
Winds will remain breezy overnight as stronger pressure rises move
through, although the potential for 50 mph gusts to mix down
decreases overnight into Tuesday as 850-750 mb winds decrease.
Blowing/drifting snow will be a bit of an issue overnight, but then
gradually improve on Tuesday.
Upper trough will shift eastward Wednesday, and a ridge will build
over the western CONUS. Mostly dry weather can be expected through
the end of the week, except for some light snow associated with a
couple week waves Wed/Thu. Highs will gradually warm from 20s on
Tuesday to 40s and 50s by Saturday. The next trough approaches the
region late in the weekend into early next week. At this time, it
appears that the main energy will stay to the south.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 421 PM MST Mon Feb 24 2020
Widespread IFR conditions expected tonight due to low
clouds/snow. Areas LIFR conditions will occur over and near the
Black Hills. Conditions will slowly improve from north to south
on Tuesday.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning until 2 PM MST Tuesday for SDZ024.
Winter Weather Advisory until 11 AM MST /noon CST/ Tuesday for
SDZ001-002-013-014-026-030>032-041>044-046-047-049.
Winter Storm Warning until 11 AM MST Tuesday for SDZ012-025-028-
072-073.
WY...Winter Storm Warning until 2 PM MST Tuesday for WYZ057.
Winter Weather Advisory until 11 AM MST Tuesday for WYZ054-055.
Winter Storm Warning until 11 AM MST Tuesday for WYZ056-071.
&&
$$
Update...Pojorlie
DISCUSSION...Pojorlie
AVIATION...10