Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/15/21
AREA FORECAST DISCUSSION
National Weather Service Albany NY
954 PM EST Sun Feb 14 2021
Weak high pressure will result in dry conditions most of tonight.
A disturbance will bring a period of light snow, mainly Monday
morning into the afternoon. Then a stronger storm system
approaching from the mid Atlantic region will bring widespread
wintry precipitation Monday night into Tuesday, including snow,
sleet and freezing rain. The best chance for mixed precipitation
will be from around the Capital District south and east, with
heavy snow to the north and west.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 930 PM EST...Weak and broad southwest flow regime and
weak impulse seen within the several layered H2O vapor channels are
bringing in a transport of moisture into the northeast
corridor. 00Z sounding from here seems most of the moisture
have been in the mid and upper levels. However, METARs depict
low level moisture was also advecting into the region. This too
is well depicted in the HRRR/RAP/00Z-NAM3km which is a little
cause for concern overnight. Potential for a little seeder-
feeder with some light precipitation evolving overnight. There
are some weak returns seen across PA and central NY so we did
introduce some wintery mix toward sunrise across southern zones.
Low temperatures will range from the upper single digits in the
Adirondacks to lower-middle 20s in the mid Hudson Valley and
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
Winter Storm Warning in effect for the The southern
Adirondacks, Lake George Region, and western Mohawk Valley 7 PM
Monday to 4 PM Tuesday...
Winter Storm Watch in effect for the rest of the region south
and east of the Adirondacks and western Mohawk Valley from late
Monday afternoon through Tuesday afternoon...
A weak disturbance in southwest flow regime aloft will quickly
move in, with light snow developing from west to east by mid to
late Monday morning. Forcing is from weak isentropic lift
associated with an inverted surface trough approaching from the
south/west. This first part of the storm will more of a nuisance
snowfall, ending late Monday afternoon. Accumulations expected
to be mainly in the half inch to one inch range, with slightly
less than an inch south and east of Albany. High temperatures
will still be below freezing and mainly in the 20s. We are still
anticipating a brief break in the snow from late Monday
afternoon into early evening, as the first disturbance moves
east of the region and the stronger storm starts to approach
from the south. Latest hi-res guidance such as the HRRR and
NAMNest support this trend.
Precipitation coverage and intensity will increase
substantially by late Monday evening to around midnight, in
response to intensifying low level southerly winds and
strengthening isentropic lift on the 290K surface. The cyclone,
with origins along the Gulf coast, will have abundant moisture
to work with, evidenced by forecast 850 mb moisture flux
anomalies of +2 to +4 STDEV (from 12Z GEFS) southeast of Albany.
This will result in moderate to heavy precipitation, with the
highest impact period overnight Monday into Tuesday morning. The
cyclone is forecast to track from the southern Appalachians
Monday evening to near NYC by Tuesday morning.
The main forecast challenge will be determining snow vs.
sleet/ice amounts across mainly the central part of the area,
including the Capital District and southern VT. To the north and
west there is fairly high confidence in heavy snowfall, with
primarily a mix of sleet and freezing rain south/east of Albany.
In the middle is where there is low confidence in how much snow
will fall before changing to sleet and possible freezing rain
as the warm nose aloft tracks northward. 12Z model guidance has
trended slightly farther north with the storm track and slightly
warmer with the warm nose aloft. Details still difficult to pin
down due to snow/ice amounts being very sensitive to slight
changes in the storm track.
So, our best forecast at this time is for heavy snow 6-12
inches across the western/southern Adirondacks, Lake George
Region and western Mohawk Valley. Some sleet may briefly mix in,
but overall should not affect snow totals. This is where we had
high enough confidence to upgrade to a Winter Storm Warning. We
continued the Winter Storm Watch for areas south/east of the
Warning area due to lower confidence in snowfall totals vs.
sleet/ice. At this time we are forecasting 4-8 inches for the
central part of the area (more north/less south), including
sleet which could occur for several hours as the warm nose aloft
reaches above 0C but with a fairly deep sub-freezing layer
beneath it cooling to around -4C or -5C. We expanded the Watch
to include the mid Hudson Valley, central and southern Taconics,
southern Berkshires, and Litchfield Hills due to increased flat
ice amounts (1/4" to 1/3"), along with 1-2 inches snow/sleet.
Overall, the forecast will likely need additional adjustments
with even subtle changes in the storm track.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Another potential high impact winter weather event Thursday into
We say goodbye to our first event with residual upslope and lake
effect snows Tuesday night. While additional accumulations will be
light, the concern will be dropping temperatures as H850
temperatures return back below zero celsius where any standing water
or untreated surfaces from earlier will become frozen. A brisk
northwest breeze to be expected as well due to tight pressure
gradient across the entire region. Lows should range from near zero
across the Dacks to mid-teens south of Albany.
Wednesday into Wednesday, a period of tranquil weather (calm before
the storm) as 1030+mb surface high slides across the area. Lake
effect clouds should diminish with at least partly cloudy to most
clear skies Wednesday, then increase clouds Wednesday night. Highs
Wednesday mainly into the 20s with overnight lows into the single
digits and teens (likely earlier in the evening before clouds
Deep moisture transport advances northward ahead of digging upstream
trough and associated surface wave across the Gulf Coast States. As
the departing surface high tracks into northern New England, the
main question remains the eventual surface low track and
precipitation types. The operational GFS appears the warmest with
the GFSv16 not too far behind. This would suggest a snow to sleet
and freezing event for most of the region. The GGEM/ECMWF are on
the colder side of the guidance envelope which would confine the
wintry mixture to the southeast of Albany. For now, per
coordination from surrounding offices and ensemble approach, we will
blend these aforementioned guidances at this time with a moderate to
potentially heavy wintry mixture for the region Thursday into
Friday. It is possible we will get above freezing Friday for a
period of time for many locations.
Friday night into Saturday, residual impacts from departing storm as
main upper trough remains upstream and forecast to move across the
region into Saturday. This will keep the threat for snow showers
and potential for lake effect snow developing somewhere over western
areas. Highs into the 20s with lows into the teens. Looking ahead
into the second half of the weekend, the weather appears to calm
down a bit before yet a potentially another system approaches.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR conditions at this time, however, this should lower to MVFR
through late this evening and continue overnight with moisture
transport advection into the region. Did bring in a VCSH toward
sunrise along with some mist.
On Monday, an area of precipitation, mainly snow, is expected to
overspread the TAF sites between roughly 14Z-17Z/Mon. MVFR
flight conditions to IFR (especially for Vsbys) once the snow
begins. Some sleet may be mixed with the snow at KPOU.
Light/variable winds are expected tonight through Monday
morning, trending into the north to northeast at 4-8 KT by
Monday Night: High Operational Impact. Definite SN...FZRA...SLEET.
Tuesday: High Operational Impact. Definite SN...FZRA...SLEET.
Tuesday Night: Low Operational Impact. Slight Chance of SHSN.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: High Operational Impact. Definite SN.
Thursday Night: High Operational Impact. Definite SN...SLEET.
Friday: High Operational Impact. Numerous SHRA...SHSN...SLEET.
No hydrological issues are expected through the next several days.
Temperatures are expected to remain at least slightly below normal
and mainly below freezing, allowing ice to expand and thicken on
area waterways. Widespread snowfall and/or mixed precipitation is
expected Monday into Tuesday which will generally add to the
snowpack. Chances for a wintry mix, including sleet and freezing
rain are possible for much of the area but especially from I-90 in
NY and southern Vermont to points SE.
Another potentially significant storm may affect the region Thursday
into Friday, with another round of snow and/or a wintry mix.
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
CT...Winter Storm Watch from Monday afternoon through Tuesday
afternoon for CTZ001-013.
NY...Winter Storm Watch from Monday afternoon through Tuesday
afternoon for NYZ039>041-047>054-058>061-063>066-083-084.
Winter Storm Warning from 7 PM Monday to 4 PM EST Tuesday for
MA...Winter Storm Watch from Monday afternoon through Tuesday
afternoon for MAZ001-025.
VT...Winter Storm Watch from Monday afternoon through Tuesday
afternoon for VTZ013>015.
Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
538 PM MST Sun Feb 14 2021
.AVIATION...00Z TAF CYCLE
An ongoing winter storm will continue to contribute to aviation
concerns through the morning. MVFR conditions will continue, with
occasional drops into IFR/LIFR ceilings if snow showers move over
terminals, though actvitity tapers off starting now through 6Z.
In addition, east and southeast winds at 10G20KTS at KDMN and KLRU
will result in blowing snow reducing visibilities to the
LIFR/VLIFR categories on occasion through 06Z. Ceilings will
remain in MVFR categories through morning.
.PREV DISCUSSION...222 PM MST Sun Feb 14 2021...
It`s been a cold, blustery, and snowy Valentines Day across the
Borderland. Snow showers will linger through the evening hours
before gradually tapering off. Low temperatures tonight will be
dangerously cold, but will feel even colder as winds create below
zero degree wind chills, with -10 to -20 degree wind chills in
the Sacramento Mountains. Temperatures will struggle to warm much
on Monday, but at least there will be a lull in the precipitation.
Our next pair of weather makers will move in for Tuesday and
Wednesday with another round of mountain snow, though lowlands
should see mostly rain. Highs will seem warm to us Tuesday and
Wednesday, but will be in the lower 50s. The Borderland will
finally dry out and warm back up for the very end of the week.
.SHORT TERM...Tonight and Monday...
Winter weather conditions continue through the afternoon and
evening hours. The cold front moved earlier than expected this
morning, which brought more snow in the lowlands than what was
previously forecasted. Snow amounts amounts in the lowlands have
ranged from 1 to 5 inches, while the Sacramento Mountains have had
accumulations up to 6 inches through the morning hours.
The front is currently up to the Continental Divide, while the
trough axis is around west TX, per water vapor satellite imagery.
The RAP shows differential vort advection along the Rio Grande
Valley along with strong frontogenetic forcing. Thus, we are
expecting more snow showers to develop in this area. West of the
divide temperatures remain above freezing, but periods of rain and
snow showers are possible into the evening hours as the front pushes
again farther west as we lose diurnal heating. The HRRR shows
another vort max around the Gila Region this evening which will
bring another few inches of snow (2-4 inches).
Now that we have this arctic airmass across the Borderland
temperatures are going to be really cold overnight and tomorrow.
East to northeast winds at the surface persist through the night
advecting this cold air. The farther east you are the colder the
temperatures will be. Morning lows will be 10 to 35 degrees below
normal. Otero and Hudspeth county will have temperatures in the
single digits. The Sacramento Mountains will have temps below 0F. We
will also have some breezy conditions. So, wind chill will be very
dangerous across portions east of the Rio Grande. Wind chills below
0F will be possible across El Paso, Hudspeth, and Southern Otero
counties, even portions of the Tularosa Basin. We have a wind chill
advisory in effect for these areas from this evening through
tomorrow morning. The Sacs will see wind chills below -18F, thus we
have a wind chill warning through noon tomorrow.
Temperatures will try to go back to above freezing by tomorrow
afternoon as the winds switch back to the west. This action should
push the arctic air back east into the plains. Skies will remain
mostly cloudy which will make it quite hard for temperatures to warm
up significantly. So, GEFS plumes show temperatures going back to
above freezing around El Paso in the late afternoon, but once the
sun sets we will go back again to below freezing. However,
temperatures tomorrow night should not be as cold as tonight.
.LONG TERM...Tuesday through Monday...
The brief lull in active weather will come to an end on Tuesday
as a shortwave trough digs down into the Four Corners region and
then into the Borderland. Expect precipitation to begin in the
Gila region and Sacramento Mountains Tuesday morning. Snow levels
there will be around 4000- 5000 feet initially when the precip
moves in, so all elevations in the mountains will see snow, but
throughout the afternoon snow levels will rise to around 6000-6500
feet. Precip will spread into the lowlands through the day, but
with snow levels mostly staying around 5500-6500 feet, the precip
will fall as rain. Additionally, winds will become quite strong
with this system. Most models indicate that westerly wind speeds
will be just below Advisory criteria through the late evening
We`ll get a brief lull in the activity Tuesday night into Wednesday
morning, but a secondary trough looks to develop behind the first
one and push down into our area during the day on Wednesday. Also, a
backdoor cold front will try to slide closer from the east. The
front`s reach looks to only reach to the Rio Grande valley at the
most, but the front will provide additional lifting for the moisture
pushing in with the trough. The second round of precip looks to be
brief with a time frame of Wednesday afternoon through the early
overnight hours. With this timing and cooler air being ushered in
with the weather system, snow levels will likely hover around 4000-
5000 feet through this event. In other words, the mountains will see
all snow Wednesday afternoon through Thursday morning. Parts of the
lowlands may see a rain/snow mix late in the evening Wednesday
before the moisture exits the area Thursday morning. All in all,
the Sacramento Mountains may see another 4 to 6 inches through
Thursday with 2 to 4 inches in the Gila. Temperatures Tuesday
will "warm" up into the lower to mid 50s as zonal flow takes over
ahead of the next weather system. Highs will fall into the upper
40s to lower 50s for the lowlands on Wednesday as slightly cooler
air pushes in with the deepening trough in the Plains. The
mountains will likely stay below freezing all day Wednesday.
The Borderland looks to finally dry out on Thursday. Temperatures
may actually remain in the lower 50s for another day as easterly
flow at the surface persists behind the push of that backdoor cold
front. Clouds will gradually clear throughout the day leading up to
a much nicer end of the week. Our flow will become more westerly
through the day on Friday warming temperatures into the lower 60s,
right around where we should be for this time of year. Pure
zonal/westerly flow over the weekend will push highs to around 70
degrees. This will be nice time to sit back and thaw out from the
frigid and snowy conditions the Borderland is seeing today.
Winter storm continues to move through this afternoon with snow for
all locations and windy conditions. Expecting most of the snow to
exit the area overnight tonight, though a few lingering snow showers
will be possible in the Sacramento Mountains Monday morning. Gusty
winds will also subside throughout the late evening hours.
Temperatures tonight will be dangerously cold in the single digits
to teens most everywhere. Wind chill values will drop to -10 to -20
in the Sacramento Mountains down into Hudspeth County, with low
single digits along the Rio Grande Valley, making it dangerous to
spend time outdoors. Monday will be partly cloudy and cold with
highs struggling to reach freezing east of the Rio Grande. Our short
break in active weather will come to an end by Tuesday morning as
another weather system moves in. Snow will start in the mountains
Tuesday morning with rain spreading into the lowlands through the
afternoon. Some of the lowlands may have a rain/snow mix briefly
Tuesday morning and again Wednesday morning as another round of
precip pushes through. Don`t expect snow accumulations in the
lowlands, though the Gila region may see another 2 to 4 inches of
snow and 4 to 6 inches in the Sacramento Mountains. High
temperatures will "warm" into the lower 50s Tuesday and Wednesday,
though staying below freezing in the mountains.
We look to finally dry out for the second half of the week with
temperatures quickly jumping back up to well above normal. Min RHs
will remain above 30-40 percent through Tuesday, then 25-35 percent
on Wednesday, and falling to 18 to 24 percent for the second half
of the week. Vent rates will be poor to fair Monday, very good to
excellent Tuesday and Wednesday, and becoming poor once again for
.PRELIMINARY POINT TEMPS/POPS...
El Paso 12 37 29 55 / 30 0 0 20
Sierra Blanca 5 31 24 53 / 30 0 0 20
Las Cruces 12 37 28 52 / 60 0 0 30
Alamogordo 8 30 21 48 / 50 20 0 60
Cloudcroft -3 17 15 28 / 60 30 10 70
Truth or Consequences 14 38 29 51 / 40 10 0 40
Silver City 18 35 30 41 / 80 0 0 70
Deming 14 42 29 52 / 60 0 0 40
Lordsburg 16 45 29 51 / 50 0 0 50
West El Paso Metro 12 38 31 55 / 30 0 0 30
Dell City 0 30 15 52 / 30 0 0 30
Fort Hancock 8 37 22 59 / 30 0 0 10
Loma Linda 6 28 25 48 / 30 0 0 30
Fabens 10 37 26 57 / 30 0 0 20
Santa Teresa 9 36 26 54 / 30 0 0 30
White Sands HQ 14 33 28 50 / 60 0 0 40
Jornada Range 9 34 24 50 / 60 0 0 30
Hatch 14 40 26 52 / 70 0 0 30
Columbus 16 44 32 56 / 40 0 0 30
Orogrande 8 32 22 50 / 50 0 0 40
Mayhill -5 30 20 40 / 50 10 0 60
Mescalero -3 24 16 37 / 60 30 20 70
Timberon -2 22 14 36 / 50 20 0 60
Winston 7 36 21 43 / 50 10 10 60
Hillsboro 11 41 25 48 / 80 0 0 40
Spaceport 11 35 24 50 / 50 0 0 40
Lake Roberts 14 36 24 40 / 90 0 0 70
Hurley 10 37 27 45 / 70 0 0 60
Cliff 20 42 29 47 / 80 0 0 70
Mule Creek 23 39 31 42 / 70 0 0 70
Faywood 15 37 29 45 / 70 0 0 50
Animas 16 49 32 54 / 30 0 0 40
Hachita 13 46 30 54 / 40 0 0 40
Antelope Wells 18 50 34 57 / 30 0 0 30
Cloverdale 22 45 34 50 / 20 0 0 40
NM...Winter Storm Warning until 11 PM MST this evening for NMZ402-403-
Wind Chill Advisory until noon MST Monday for NMZ413-417.
Wind Chill Warning until noon MST Monday for NMZ414>416.
Winter Weather Advisory until 11 PM MST this evening for NMZ401-
TX...Winter Storm Warning until 11 PM MST this evening for TXZ418>424.
Wind Chill Advisory until 9 AM MST Monday for TXZ418-419.
Wind Chill Advisory until noon MST Monday for TXZ420>424.
Area Forecast Discussion
National Weather Service Indianapolis IN
958 PM EST Sun Feb 14 2021
The NEAR TERM Section has been updated below.
Issued at 248 PM EST Sun Feb 14 2021
Snow will move in late this evening and into the overnight hours
with more significant snow arriving tomorrow and tomorrow night. A
brief break in precipitation for Wednesday before the next wintry
round arrives Wednesday night. Slightly warmer weather returns
.NEAR TERM /Overnight/...
Issued at 958 PM EST Sun Feb 14 2021
Surface analysis late this evening shows high pressure in place
over MN...providing the dry and cool arctic air on northerly winds
across Central Indiana. Aloft water vapor showed a large trough in
place over the southern plains...with a SW flow of warmer and
more moist air spreading northeast toward the Ohio Valley. Radar
shows te first wave of snow over southern Illinois...streaming
northeast. HRRR takes this area of snow and slwoly pushes it
across the forecast area overnight. Forecast soundungs show deep
saturation through the night. Thus the ongoing forecast appears
on track for precipitation onset after midnight with accumulations
through the night.
Given the increasing and thinkening clouds across the area have
trended temps to be steady or slowly rising.
.SHORT TERM /Tomorrow and Tomorrow night/...
Issued at 248 PM EST Sun Feb 14 2021
The upper level trough and associated surface low pressure system
that is currently bringing hazardous winter conditions to the
Southern Plains will be tracking to the northeast through the day
tomorrow with initial impacts of the system arriving by the
morning hours tomorrow. 12Z model guidance has come much closer in
line, although much different than where we stood yesterday. The
synoptic low looks to begin to close with much stronger surface
cyclogenesis along with a slightly more northerly track. This is
leading to the axis of heaviest snow to fall more over central
Indiana than southern Indiana and Kentucky.
Moisture transfer vectors at 700 and 850mb also are showing a
deeper intrusion of Gulf air further into the Ohio Valley which
has upped the QPF values from yesterday. This increase is due to
the much stronger low at 700mb and the fact that it looks to close
off late tonight. Snow ratios still look a bit too high based
mainly on the fact that although temperatures are favoring the
higher ratios, much of the snow production is happening at warmer
temperatures due to the warm nose aloft associated with the WAA
advection ahead of the low. The warm nose will gradually erode due
to evaporative cooling which will allow for those higher ratios
later in the night.
Snow will ramp up during the daytime hours with the heaviest snow
occurring between 4PM and 12AM tomorrow. Snow accumulations
during that time are likely to excess an inch an hours with
periods of 2+ inches per hour. In addition to all the snow, winds
will frequently gust in excess of 20 mph with occasional gusts of
30 mph. This will lead to blowing snow, especially with the low
water content of the snowfall. Snow will then begin to come to an
end by Tuesday morning with additional blowing snow possible
through the day.
The best lift is closer to -8C which doesn`t favor the 25:1 to as
high as 30:1 snow ratios that the kuchera method is throwing out.
That leads to the extreme snowfall graphics that have been posted
around social media last night and today. More reasonable ratios
will be around 16:1 in the SE to 20:1 in the NW with ratios
increasing through the night. All that leads to snowfall amounts
of 8-11 inches pretty much across the board for central Indiana,
although locally higher amounts are a given. With that in mind,
upgraded the Winter Weather Advisory into a Winter Storm Warning
for all sites across the forecast area.
.LONG TERM /Tuesday through Sunday/...
Issued at 248 PM EST Sun Feb 14 2021
Tuesday morning begins with surface low pressure centered near PA/NJ
and heading northeast from there, with high pressure over much of
Ontario stretching back through MN and into the eastern plains
states. A broad upper trough will be in place over much of the
central U.S. A lobe of upper energy over northwestern Canada will
start to strengthen and dip southward, increasing the strength of
the trough over the intermountain west and weak ridging moves
through central indiana Tuesday night into Wednesday as a downstream
result. The deepening upper trough then spends Wednesday through
Friday swinging out of the intermountain west and toward the eastern
U.S. and finally off the east coast on Saturday/Sunday.
As the strengthening trough moves eastward Wednesday/Wednesday
night, it induces cyclogenesis over the Gulf and and then pulls the
low northeast ahead of itself. A warm front firms up from
Mississippi through WV and the low then tracks along it Wednesday
night through Thursday night. A strong low level jet is produced
ahead of the low that will draw significant moisture and warm air
northward from the Gulf. Forcing from isentropic lift and some
frontogenesis will be the main players on Wednesday night, but
Thursday during the day significant upper forcing will arrive with
the low level jet continuing to provide forcing as well. This
system continues to show potential to produce significant
impactful winter weather across central Indiana. Still big
questions on how far north the warm nose will get, but this set of
model runs is a little further south with that than those
yesterday, which would trend this in more of a snow rather than
mixed precipitation/ice direction. Heavy snow looks possible with
this event and it merits monitoring.
Friday into the weekend high pressure slides through and could bring
a dry stretch to central Indiana.
Below zero wind chills are possible early Tuesday morning, and low
temperatures from near zero to the single digits, along with wind
chills below zero, are expected Wednesday morning. Snowpack could
decrease the temperatures to end the week and move into the weekend,
but right now with the pattern starting to move a bit could see
highs above freezing on Sunday.
.AVIATION /Discussion for the 150000Z Tafs/...
Issued at 644 PM EST Sun Feb 14 2021
IMPACTS: Flying conditions are expected to deteriorate to MVFR
this evening...with IFR conditions expected at times on Monday
DISCUSSION: Obs across the area indicate some holes within the
MVFR cigs...namely at IND...but this will only be a short reprieve.
Cold air in place at the surface along with a moist flow aloft
will make for cloud cover once again overnight. Upper support is
expected to arrive overnight as a short wave is ejected from the
deep upper trough in place over the southern plains states.
Forecast soundings show deep saturation arriving tonight and
persisting through the end of the TAF period...thus MVFR or worse
will be expected...with periods of IFR expected on Monday
afternoon and evening as the strongest forcing moves through the
CONFIDENCE: High confidence for deteriorating flying conditions
this taf period.
Winter Storm Warning until 7 AM EST Tuesday for INZ021-028>031-
Area Forecast Discussion
National Weather Service Key West FL
1053 PM EST Sun Feb 14 2021
Winter weather over the Southern Plains has captured all the
weather headlines right now. In contrast, the Florida Keys are on
the other side of the cold front over the Central Gulf, with the
00z KEY sounding showing deep S-SW flow aloft. This has pumped up
quite a warm and muggy air mass. Low temps tonight should bottom
out in the mid 70s, and dewpoints are in the more May-like 73-75F
range. A few moderate to heavy showers have developed in the
confluent southerly flow, mainly near the Tortugas and south of
the Middle Keys. The HRRR model shows expansion of shower coverage
for the Middle and Upper Keys during the next few hours, before
convection exits north late tonight.
Southerly flow aloft will continue on Monday. During the daytime,
this is typically favorable for dry weather downwind of Cuba.
Then by Monday evening, we will be watching the slug of moisture
that is currently rounding the subtropical ridge near the Cayman
Islands. Satellite-derived PW imagery shows PW values of 1.7"-1.9"
in this slug, and it will be lifting north with its deeper
moisture across the Keys late Monday and Monday night. It could
possibly bring near-record PW values for this time of year. With
such rich moisture, and a cold front trying to push into the
eastern Gulf, there should be quite a blossoming of showers and
perhaps thunderstorms on late Monday and Monday night.
Southeast to south winds prevail across the waters tonight. Satan
Shoal buoy only shows 1-foot seas, but Pulley Ridge (88 NW of
Fort Jefferson) is showing 4-foot seas from the southwest.
From synopsis...Through Monday, the waters will lie between high
pressure south of Bermuda and low pressure over the western and
central Gulf. A cold front will reach the southeast Gulf on
Tuesday but then retreat back toward the central Gulf on Tuesday
night, bringing a brief wind shift across mostly the western
waters. A potent low pressure system will develop over the western
Gulf of Mexico on Wednesday, racing to the northeast to east
Wednesday night and Thursday. Southeast breezes will freshen
Wednesday and Wednesday night in advance of the deepening surface
low in the Gulf of Mexico. A strong cold front will surge
southeast Friday with widespread fresh to strong breezes.
Radar currently shows a few heavy showers about 15-40 miles south
of MTH, moving to the north. These will pass in the vicinity of
MTH through 06z. After that, this activity will move off to the
north, leaving a rain-free TAF for the island terminals. SE-S
surface winds will prevail.
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Area Forecast Discussion
National Weather Service Memphis TN
1003 PM CST Sun Feb 14 2021
Not a whole lot of change to the forecast. Latest KNQA radar sweep
shows two areas of precipitation occurring at this hour. One
moving into eastern Arkansas, which is predominantly snow with
some sleet mixed in. The other area is lifting through west
Tennessee near the Tennessee River, which contains mostly sleet.
That sleet has created a host of problems for folks traveling I-22
and I-45 in and around Tupelo.
The current precipitation is progged to lift north of the area
just after midnight with a lull for about 2 to 3 hours. The next
area of moisture is currently located over the ArkLaTex, and will
pivot into the Mid-South overnight. This is going to the brunt of
the storm, with QPF values approaching nearly 3/4 of an inch
through tomorrow afternoon. With a 13 or 14 to 1 Snow-to-Liquid
ratios, snow totals will likely exceed 5 to 6 inches with some
areas seeing as much as 9 to 10 inches.
Models are very consistent with the all snow line setting up
nearly parallel to the I-40 corridor. This will result in the
highest snowfall totals occurring mainly along and north of I-40.
There is some concern, especially in Memphis, that sleet could be
the main p-type overnight. This could result in a few inches of
sleet. However, the trend has been mostly snow in Memphis despite
the elevated and small warm nose between 850 and 800mb. Further
south of I-40, a wintry mix looks likely overnight with a
transition to snow and sleet tomorrow morning. The main area to
watch will be along and east of the Natchez Trace, where freezing
rain and sleet could create some big impacts.
Nudged the snowfall totals up a little bit over southeastern
Arkansas and adjusted apparent temperatures to reflect current
trends. The forecast is in good shape with an exceptional winter
storm peaking early Monday morning into the afternoon hours.
.PREV DISCUSSION... /issued 322 PM CST Sun Feb 14 2021/
Wintry precipitation has already been moving into the Mid-South
today. Thus far precipitation has been in the form of snow and
sleet. With the cold temperatures in place, some minor
accumulations have already occurred in locations that have
received precipitation. Heavier bands will continue to move into
the area this evening. Looking at KNQA radar, one band will be
moving into Eastern Arkansas within the next hour or two. The
bands this evening will be associated with the lead shortwave
moving through the upper trough. Temperatures have not budged much
today with current temperatures ranging from the mid teens along
the Mississippi Delta to the upper 20s in Monroe County,
Mississippi. Don`t expect temperatures to drop much tonight as the
precipitation moves in.
A brief lull may occur during the overnight hours as the lead
shortwave lifts off to the northeast. However, the heaviest
precipitation will spread into the area by sunrise Monday
continuing through the day. With confidence growing that strong
frontogenesis will occur with high snow-to-liquid ratios, and a
saturated dendritic growth zone, snow totals have been bumped up
across Eastern Arkansas, the Missouri Bootheel, and Northwest
Tennessee including the Memphis Metro area. Amounts will range 6-9
inches in this area. Although, can`t totally rule out isolated
higher amounts. In addition, can`t rule out some sleet occurring
briefly on the southeastern edge of this corridor. Also with the
system deepening, wouldn`t be totally shocked to hear some claps
of thunder in this area, but at this time will not mention thunder
in the forecast. Blowing snow will also be a risk due to the
gusty northerly winds. This will reduce visibilities even further.
The HRRR was showing visibilities near zero at times in Eastern
Arkansas up into portions of West Tennessee due to the
combination of heavy and blowing snow.
South of this corridor, from Tallahatchie County northeastward to
near Hardin County Tennessee, sleet will likely be the biggest
impact. However, can`t rule out freezing rain occurring and a
change over to snow late Monday as the system moves out. A lot
will depend on how deep the warm layer just above the surface is
and how long it lasts before it disappears.
For areas southeast of Tupelo, freezing rain will be the main
threat with ice accumulations expected to be over a quarter of an
inch. Precipitation may change over to sleet and/or snow just
before the moves out.
Expect the storm to wind down Monday evening as
the precipitation will taper off from west to east.
Bitterly cold wind chill values will also be possible through the
storm and even after the storm through much of the week as
temperatures remain frigid due to the significant accumulations.
Another major winter storm will begin to impact the Mid-South late
Tuesday Night into Wednesday as a second potent upper level trof
approaches the region. Although, the heaviest precipitation will
occur Wednesday Night into Thursday as the upper trof moves into
the area. Right now, the track of the storm is almost identical
to the one that is occurring tonight into Monday. Significant
accumulations will be possible with this system as well. Stay
tuned to the latest forecasts as the storm gets closer in time.
Went below guidance for temperatures for Friday into next weekend
due to the expected accumulations from two systems.
Light snow continues across much of the area, though we are
beginning to see some pockets of more convective sleet lifting
north across north MS. Given the amount of arctic air in the
surface layer, we`re seeing more snow than we would normally
expect given the thermal profiles, resulting in slightly less
confidence in precipitation types this evening. We expect
predominantly snow at MEM/JBR/MKL, but some sleet will likely mix
in at times. Farther southeast at TUP, we`re expecting mainly
sleet with some freezing rain.
Lift will increase late tonight and Monday, gradually cooling the
warm layer aloft. This will allow precipitation to transition to
all snow, heavy at times, much of the day tomorrow. This may be
delayed a bit at TUP, but they should eventually transition as
well. Ceilings will deteriorate to 500-1000 ft AGL with low
visibility expected within the areas of snow. Improvement is
expected from southwest to northeast by tomorrow evening. North
winds will persist at 10-15 kts, occasionally gusting to around 20
AR...Winter Storm Warning until midnight CST Monday night for Clay-
MO...Winter Storm Warning until midnight CST Monday night for Dunklin-
MS...Winter Storm Warning until midnight CST Monday night for Alcorn-
TN...Winter Storm Warning until midnight CST Monday night for Benton
Area Forecast Discussion
National Weather Service Mobile AL
1002 PM CST Sun Feb 14 2021
.NEAR TERM /Now Through Monday night/...A multitude of weather
impacts are expected through the period stretching from wintry
weather over the northwestern portion to a possibility for some
severe storm development over the extreme southeast portion.
Within a large scale (5-Wave) upper trof pattern over much of the
CONUS, a vigorous embedded shortwave trof over the southern Plains
ejects off towards the Great Lakes during the period, with a
second vigorous shortwave system following closely behind. A
surface low has developed over the northwest Gulf in response to
the lead shortwave system, with a frontal boundary extending
roughly eastward to the northern Florida peninsula. The surface
low is expected to track into Georgia by Monday evening before
continuing further off to the north, while a massive dome of
arctic air currently in place over the Plains builds into the
A series of lesser shortwaves will move across the area as
the shortwave trof approaches, and in response isolated patches
of precipitation will develop late tonight along and west of a
line from Wiggins, MS to Butler, AL. As these shortwaves continue
along with the approach of the surface low, the coverage of
precipitation becomes widespread over interior southeast
Mississippi and interior southwest Alabama tapering to isolated
patches of precipitation well of the east. Widespread
precipitation follows for most of the area during the early
afternoon hours, then as the surface low moves off to the east the
precipitation comes to an end over the western portion of the
area in the afternoon, followed by the remainder of the area by
the late evening hours. Model soundings and surface temperatures
will support this precipitation falling as a mix of freezing rain
and rain over portions of interior southeast Mississippi and
interior southwest Alabama beginning as early as late tonight and
continuing through the early afternoon hours until the
precipitation comes to an end. A Winter Weather Advisory remains
in effect from 3 am tonight until 3 pm Monday for Wayne, Perry,
Greene, Stone counties Mississippi and for Choctaw, Washington and
Clarke counties Alabama. Ice accrual amounts of up to a tenth of
an inch are possible within the advisory area, and there is a
small change that higher ice accrual amounts could occur over
Choctaw and Wayne counties which could possibly reach Winter Storm
Warning criteria. This will be monitored. Over the remainder of
the forecast area, rain is expected.
Regarding the cold air building into the area noted in the first
paragraph, an interesting trend has been noted in the Nam, GFS,
Euro, and Canadian which have all trended towards a quicker
advancement of the colder air into the region on Monday, albeit to
varying degrees. The extended HRRR and RAP guidance also show
this trend. This trend is reflected in the latest guidance for the
trajectory of the surface low, which moves to just south of the
Alabama coast by noon Monday, with a warm front extending eastward
to just south of Apalachicola before zipping quickly off into
central Georgia Monday evening. This modest change in the
trajectory of the surface low by the area means that the warm
front will likely just be able to advance into a portion of the
western Florida panhandle Monday afternoon before the surface low
passes by. SBCAPE values of up to 400 J/kg will be present in the
wake of the front within a highly sheared environment. These
conditions will be supportive of potential severe storm
development Monday afternoon over the extreme southeast portion of
Wind chill values will drop to around 5 degrees over interior
southeast Mississippi and a portion of southwestern Alabama from
10 pm Monday until 9 am Tuesday, and a Wind Chill Advisory is now
in effect for this portion. In addition, the Hard Freeze Watch has
been upgraded to a Hard Freeze Warning for this same area and time
duration. Lows tonight range from the lower to mid 30s over the
northwestern portion of the area to the mid 40s over the eastern
portion. Highs on Monday range from a rather chilly mid to upper
30s over the northwestern portion of the area to the upper 50s to
around 60 mainly over portions of the western Florida panhandle.
Lows Monday night will be just plain cold and range from the mid
teens to lower 20s along and west of I-65 to the mid to upper 20s
further to the east. A moderate risk of rip currents continues
through the period. /29
AL...Hard Freeze Warning from 10 PM Monday to 9 AM CST Tuesday for
Winter Weather Advisory from 3 AM to 3 PM CST Monday for
Wind Chill Advisory from 10 PM Monday to 9 AM CST Tuesday for
MS...Hard Freeze Warning from 10 PM Monday to 9 AM CST Tuesday for
Winter Weather Advisory from 3 AM to 3 PM CST Monday for MSZ067-
Wind Chill Advisory from 10 PM Monday to 9 AM CST Tuesday for
GM...Small Craft Advisory from 8 AM to 6 PM CST Monday for GMZ631-632.
Small Craft Advisory from 8 AM Monday to 6 AM CST Tuesday for
This product is also available on the web at:
Area Forecast Discussion
National Weather Service Paducah KY
549 PM CST Sun Feb 14 2021
Issued at 549 PM CST Sun Feb 14 2021
The AVIATION section has been updated for the 00Z TAF issuance.
.SHORT TERM...(Tonight through Monday night)
Issued at 238 PM CST Sun Feb 14 2021
A major winter storm is taking aim on the area. The first round of
snow will be tonight in a zone of increasing low/mid trop
frontogenetical forcing positioned out ahead of the main upper trof,
that by 12z Monday should be over the central and southern Plains.
We may see an initial 1-3" of snow tonight (give or take). We have
incorporated the HREF closely with a consensus of deterministic
guidance for tonight and Monday (see below). We will be close to
Wind Chill Advisory conditions again tonight across portions of
southeast MO and southwest IL. We have addressed the bitter cold in
our current Winter Storm Warning that remains as is from 6 PM
Tonight through 6 AM Tuesday.
Monday, the main energy within the mid level trof comes up over top
of the region in the afternoon and evening. This will be the round
of greatest significance (snow rates, accumulations, impacts). The
overall trend seems a bit faster, so the lull is not expected to
last real long.
WPC banding probabilities increase notably with the main wave, with
some inference of instability and prominent snowfall rates. The HRRR
depicts this possibility as well. So for now we have storm total
accumulations 6 to 12". Given above average snow to liquid ratios
and this added concern, 12" may not be high enough should some of
these indicators pan out. But for now, we have headed the right
direction in our opinion.
The snow will taper off Monday evening and should be all but
completely over across southwest IN and the KY Pennyrile region
In terms of messaging, the bitter cold remains a real concern with
this system, as does the potential for blowing snow with NNE winds
10 to 15 mph gusts to 20 mph or even slightly higher. Stay tuned for
updates and adjustments to snow amounts (if needed).
.LONG TERM...(Tuesday through Sunday)
Issued at 238 PM CST Sun Feb 14 2021
The main focus later this week continues to be another potential
winter storm Wednesday into Thursday. This system is still four days
away, so many details remain to be ironed out. The 500 mb pattern
actually appears more complex than it did yesterday, mainly because
a northern stream 500 mb shortwave has entered the picture. This
northern stream shortwave will move down into the northern Plains
mid-week. There is some potential for this shortwave to shunt our
moist southern stream shortwave further south. This is reflected in
a majority of the model qpf fields, which show the heavy qpf
suppressed more to the south of the Ohio Valley than they did
yesterday. There is also less of a warm air intrusion, which results
in less mixing of wintry precip.
In a nutshell, the 12z models are still split into two camps. The
European solutions have trended even farther to the southeast,
taking the surface low northeast from the central Gulf Coast to
Georgia. The gfs ensemble mean is also further southeast, taking the
surface low across Alabama Thursday. The gfs consensus basically
places our region in the sweet spot for heavy snow, with heavy qpf
shown by the gfs ensemble mean over the Ohio Valley and se Missouri.
An elevated warm nose in the gfs guidance would result in mixing
with sleet or freezing rain se of the Ohio River.
Until the models resolve the influence of the northern stream
shortwave, the forecast will remain in flux. A forecast trend toward
drier and colder conditions is possible if the northern stream
becomes more dominant. The models at face value today do continue to
suggest the likelihood of a winter storm Wednesday into Thursday.
Otherwise, the main story on Tuesday into Wednesday will be the
continued bitterly cold wind chills.
Following the late week winter storm system, high pressure will pass
overhead on Friday. In the wake of the high, southwest winds are
expected to bring above freezing temps this weekend following the
extended winter blast. The ecmwf and gfs mos highs in the 50s at pah
Sunday look a little unrealistic given the snowcover, so the
forecast will be for highs in the 40s. Model ensemble means have
been in good agreement on a nearly zonal flow aloft this weekend.
Issued at 549 PM CST Sun Feb 14 2021
Snow will overspread the area through 06Z. MVFR ceilings and IFR
visibilities can be expected with the first round of snow tonight,
but a few periods of LIFR visibilities will be possible. With
gusty north winds sustained around 15kts through the period, there
will be some potential for blowing snow to keep visibilities at
MVFR or even IFR levels in the morning when we will be between
snow events. The second round of snow will spread northeast over
the TAF sites after 15Z and will continue for most of the
afternoon. The heaviest snows are expected over west Kentucky and
southwest Indiana where 1/4SM is a decent bet at some point in the
IL...Winter Storm Warning until 6 AM CST Tuesday for ILZ075>078-
MO...Winter Storm Warning until 6 AM CST Tuesday for MOZ076-086-087-
IN...Winter Storm Warning until 6 AM CST Tuesday for INZ081-082-
KY...Winter Storm Warning until 6 AM CST Tuesday for KYZ001>022.