Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/27/20
Area Forecast Discussion
National Weather Service Amarillo TX
637 PM CDT Mon Oct 26 2020
.MESOSCALE UPDATE...
...Winter Storm Conditions Returning Overnight...
* Synoptic Overview: The upper level low that has been long
advertised has developed in central Arizona and is beginning to
be cutoff from the main longwave trof pattern. Latest satellite
is showing a vorticity maxima that is gaining spin with a strong
jet supporting this feature diving in on the backside. A pair of
shortwave trofs are rounding the base of the longwave trof
access, with one already moving across the New Mexico mountains
as of this writing. This feature is timed out to arrive 27/03Z
in the western combined Panhandles, with the reinforcing feature
behind expected around 27/18Z to 28/00Z tomorrow afternoon. Both
of these features will be accompanies by sufficient mid and
upper level moisture to help resaturate these levels of the
atmosphere upon their respective arrivals.
* Mesoscale: The region remains encased within a modified arctic
airmass with northeasterly near surface flow and southwesterly
flow about 3km off the deck. The latest 27/00Z sounding suggests
that the warm nose over Amarillo has eroded sufficiently enough
to only be about 0.5-0.6 degrees Celsius. However, this erosion
of the warm nose will be shortlived with expected theta-e
advection expected to begin in earnest ahead of an approaching
disturbance tonight. The atmospheric column is expected to
saturate from the surface to H5 with the next shortwave, with
upright elevated instability once again noted of approximately
50 to 150 J/kg (not as much as yesterday). The upper level
diffluence preceding the approaching shortwave disturbance is a
telltale signal that this will help evacuate more mass in
available portions of the column to promote strong dendritic
growth and help keep hydrometeors suspended. Precipitation types
will favor snow in the northwestern and western portions of the
combined Panhandles as there is no expectation that the warm
nose will be deep enough to melt any dendrites, though sleet
because of recirculating hydrometeors could occur. Meanwhile,
theta-e advection, a re-introduction of a warm nose around H7,
and elevated instability may mean that thunderstorms could form
with sleet being possible once more. As the day progresses on
Tuesday, theta-e advection and warming aloft may even introduce
freezing rain once more.
* Threats: A brief reprieve from heavier wintry precipitation is
ongoing, though an approaching disturbance will certainly change
that around 10 PM to midnight this evening. Convective banding
is anticipated, with a slight chance of thunderstorms once more,
which will bring a sudden increase in precipitation intensity.
Snow and sleet will favor the western and northwestern combined
Panhandles, while sleet, freezing rain and snow grains will
favor the central and southeastern Panhandles.
* Timing & Location: Winter storm conditions are expected to
return for the entire Texas and Oklahoma Panhandles in the
presence of convective banding areawide starting around 10 PM to
midnight tonight and continuing through the entire day on
Tuesday.
* Summary: The short break in winter weather precipitation is
expected to end late tonight as another disturbance approaches
the region. Snow and sleet, favoring the west and northwest, is
expected and could be heavy at times in heavier banding features
or in the presence of thunderstorms. Wintry mixed precipitation
across the central and southeastern combined Panhandles, with
sleet and freezing rain, are possible becoming moderate to heavy
at times in banding features or in the presence of
thunderstorms.
Bieda
&&
.AVIATION...00Z TAFs...LIFR to MVFR conditions are prevailing at
terminals this afternoon with conditions expected to deteriorate
areawide AFT 27/06Z as the next disturbance enters the region.
Snow, which could at times be moderate or heavy, is anticipated
at KDHT and KGUY. KAMA will also experience snow, though wintry
mix is in play with freezing rain mixing in midday Tuesday. Wintry
precipitation will continue well after the TAF period is over.
The other item of concern during this TAF period is that there
could be thunderstorms, which would bring short, enhanced bursts
of heavy wintry precipitation. We are entering the worst
anticipated winter weather conditions of this winter storm event.
Bieda
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 21 16 28 25 37 / 60 90 70 90 80
Beaver OK 25 17 35 25 38 / 70 80 50 70 90
Boise City OK 19 13 33 23 38 / 70 70 40 80 90
Borger TX 25 18 31 28 40 / 70 90 60 90 80
Boys Ranch TX 23 17 30 25 38 / 70 90 70 90 70
Canyon TX 22 16 28 24 37 / 60 90 70 90 70
Clarendon TX 25 20 30 28 38 / 70 90 80 90 80
Dalhart TX 21 15 30 24 37 / 70 90 60 90 80
Guymon OK 21 14 33 24 38 / 70 80 50 80 90
Hereford TX 23 17 27 25 38 / 60 90 70 90 70
Lipscomb TX 24 18 32 25 38 / 80 80 70 80 90
Pampa TX 24 16 28 26 38 / 70 90 70 90 80
Shamrock TX 26 21 31 28 39 / 70 90 80 90 80
Wellington TX 29 22 32 28 40 / 70 90 80 90 80
&&
.PREV DISCUSSION... /Issued 317 PM CDT Mon Oct 26 2020/
SHORT TERM...Today through Tomorrow...
RAP 500mb heights show the low pressure system centered over
southeast Utah with a disturbance across western New Mexico. Water
vapor imagery shows dry air aloft, but as this disturbance moves
across the forecast area tonight it will bring with it another wave
of mid-level moisture. The low pressure system will drop down across
Arizona tonight and move east into southwest New Mexico by Tuesday
night.
Current observations across the Texas and Oklahoma Panhandles show
light snow and/or mist (freezing drizzle) with cloud decks below
2000 feet. Soundings show the shallow moisture below 700mb, with a
dry column above. A 700mb warm nose of about 2 degrees Celsius is
present mainly in the eastern Panhandles, but the observed 18z
sounding for Amarillo also shows this. The precipitation type
through this morning at Amarillo Airport has been primarily light
snow and mist, with no further accumulations.
Cooler air will filter south into the air as the system moves south,
which will cool the 700mb layer as well. Soundings show full
saturation beginning after midnight across the forecast area as the
disturbance pushes across. With ample lifting and cooling, the
chance for widespread snow/sleet returns across most of the
Panhandles. The temperatures will play a key role in whether
precipitation types are primarily snow versus sleet. Temperatures
warm into the eastern half of the Panhandles into the morning hours
Tuesday due to warm air advection both at the surface and aloft. The
chance for snow remains in the northwest as temperatures remain
cooler in this area, while the remainder of the Panhandles
changeover. The central and southeast Panhandles will likely change
over to sleet and freezing rain respectively.
Similar to today, the dry air aloft will filter in over the area and
leave the Panhandles with another lull in precipitation with some
light wintry precipitation due to lingering low-level moisture,
along with subtle amounts of lift around 850mb. The northwest will
likely keep their chance of light snow, but the central and
southeast will see more of a light freezing rain/freezing drizzle
with little to no accumulations.
Rutt
LONG TERM...Tuesday night through Monday.
The upper level low pressure system is forecast to move into far
west Texas around El Paso by 12Z Wednesday. Then model tracks
diverge, which will make all the difference in the world as to
precipitation type, amounts, and the magnitude of any dry
slotting that might occur. If the southern track of the 12Z GFS
verifies, our area will be in the cold air longer and would have
less dry slotting and more of the wraparound precipitation too.
This would result in higher QPF totals and more winter
precipitation. If the northern progged track of the 12Z ECMWF and
12Z NAM verify, our forecast area would encounter more of the dry
slot portion of the storm, which would result in less winter
precipitation on Wednesday compared to the GFS. Given these
uncertainties which are critical to the forecast, have opted to
lean with the model consensus blend for this package, which
features a compromise track and precipitation amounts Tuesday
night through Wednesday night. Expect the lower elevations off the
caprock to have more in the way of freezing rain and sleet, while
the higher elevations of the western zones on the Caprock should
have more in the way of sleet and snow. The central zones will
likely be a mix of sleet, snow, and freezing rain. Highest overall
snowfall accumulations are forecast to occur in the far western
zones. Some elevated instability is progged Tuesday night, which
could result in isold thunderstorms similar to what occurred late
Sunday night and early this morning. Utilized NBM pops and
temperatures Tuesday night through Wednesday night.
The upper level low pressure system should be east of the area
Thursday, with improving conditions anticipated. A return to dry
weather and moderating temperatures is foreseen Friday through
Monday.
02
&&
.AMA Watches/Warnings/Advisories...
TX...Winter Weather Advisory until 7 PM CDT this evening for the
following zones: Armstrong...Carson...Collingsworth...
Dallam...Deaf Smith...Donley...Gray...Hansford...Hartley...
Hemphill...Hutchinson...Lipscomb...Moore...Ochiltree...
Oldham...Palo Duro Canyon...Potter...Randall...Roberts...
Sherman...Wheeler.
Winter Storm Warning until 7 PM CDT Wednesday for the following
zones: Armstrong...Carson...Collingsworth...Dallam...Deaf
Smith...Donley...Gray...Hansford...Hartley...Hemphill...
Hutchinson...Lipscomb...Moore...Ochiltree...Oldham...Palo
Duro Canyon...Potter...Randall...Roberts...Sherman...
Wheeler.
OK...Winter Weather Advisory until 7 PM CDT this evening for the
following zones: Beaver...Cimarron...Texas.
Winter Storm Warning until 7 PM CDT Wednesday for the following
zones: Beaver...Cimarron...Texas.
&&
$$
98/7
Area Forecast Discussion
National Weather Service Lincoln IL
813 PM CDT Mon Oct 26 2020
.SYNOPSIS...
Issued at 339 PM CDT Mon Oct 26 2020
Periods of light precipitation will continue across central and
southeast Illinois overnight, with some snow and sleet possibly
mixed in as well from I-55 westward. Little or no accumulation is
expected. Another round of heavier rain is expected Wednesday
night into Thursday night. Dry weather will return to the region
Friday through Sunday. Cool temperatures will prevail through the
week.
&&
.UPDATE...
Issued at 812 PM CDT Mon Oct 26 2020
Steadier rain has been shifting south of I-70 this evening, with
patchy rain/snow mixes north to about I-72. Currently watching an
area of precipitation moving northeast through Missouri. While
radar mosaics show it closing in on the northeast corner of the
state, surface obs confirm much of the precip reaching the ground
is actually closer to the western border. HRRR model has been
backing off the last couple runs on exactly how much of this holds
together when it gets here after midnight. Just sent some updates
to the PoP trends for this, concentrating most of the 30+ percent
values south of I-72/Danville. Did also expand the early Tuesday
morning PoP`s a bit to include 25-30 percent west to around I-55.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 339 PM CDT Mon Oct 26 2020
Southwesterly flow aloft with several embedded shortwave
disturbances will continue into Tuesday morning for the central IL
area as a deep western U.S. trough continues. The trough cuts off
over the southwest U.S. Tuesday finally allowing the stronger
flow aloft to migrate northward, bringing an end to precipitation
in central IL. Temperatures will be cold enough that some mix of
snow can be expected from around I-55 westward, possibly as far
east as I-57 briefly. Expect lows tonight ranging from 28 in
Galesburg to 41 in Lawrenceville. Highs Tuesday should range from
42 in Galesburg to Lawrenceville.
&&
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 339 PM CDT Mon Oct 26 2020
Models depict the southwestern U.S. cut-off low moving over
Oklahoma by late Wednesday, bringing enough lift into southeast IL
for a slight chance of rain for Wednesday afternoon, and likely
over all of central and southeast IL by Thursday morning. As this
system advects moisture into the area associated with Tropical
Storm Zeta, precipitable water values could reach the neighborhood
of 1.5 inches. Rainfall could be heavy, and a few inches of
rainfall are possible, especially south of I-72/Danville. Dry
weather should prevail for a few days after this system pulls
eastward by Friday and high pressure dominates the region for at
least a few days. Cool weather with highs in the 50s should
prevail Wednesday through Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 617 PM CDT Mon Oct 26 2020
Much of the current precipitation is along and south of the KSPI-
KCMI corridor and will be diminishing in this area over the next
couple hours, but another surge of rain/snow may move into these
areas again after 06Z. Ceilings are starting to become more
variable, with IFR levels in eastern Illinois and a trend to
around 8,000 feet occurring west of KPIA. In general, will keep
the ceilings on the lower side, mainly MVFR, though will include a
TEMPO period of VFR conditions at KPIA this evening. More
wholesale improvements will hold off until later on Tuesday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...37
SHORT TERM...37
LONG TERM...37
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Midland/Odessa TX
604 PM CDT Mon Oct 26 2020
.DISCUSSION...
See 00Z Aviation discussion below.
&&
.AVIATION...
Forecast soundings and current observations suggest IFR conditions
will prevail for much of the next 24 hours. Hi-res models bring a
shortwave thru the area overnight, then a break Tue
morning/afternoon before the main round hits with the arrival of
the upper trough after the end of the forecast period. Latest HRRR
brings FZRA thru KMAF/KCNM overnight, w/lighter amounts KHOB.
Models are not capturing the extent of the warm nose on KMAF 18Z
RAOB, so FZRA should be the main precip type, at least in the
short term.
&&
.PREV DISCUSSION... /issued 442 PM CDT Mon Oct 26 2020/
DISCUSSION...
..Major Winter Storm Beginning to Impact the Area with Accumulating
Ice and Snow...
We are in for a dangerous winter storm over the next 48 hours for
much of west Texas and southeast New Mexico. Temperatures have
struggled to reach freezing this afternoon from I-20 north and
forecast models continue to be too warm. Most locations have seen
fog and drizzle this afternoon with the heavier precipitation
shifting east. There have been reports of accumulating ice on trees
and elevated surfaces across the northern Permian Basin into Lea
County.
Don`t let the current lull in precipitation fool you, because it
will get much worse tonight! The upper low to our west will continue
to dig into N. Mexico overnight. Southwest flow ahead of this system
will stream upper level moisture across our area while Gulf
moisture overrides the cold airmass at the surface. A disturbance
will increase lift across the region tonight and cause a
widespread round of heavy precipitation. Temperatures will fall
below freezing quickly this evening and drop into the 20`s by
morning over much of our area. The main precip type will be
freezing rain across the Permian Basin with sleet mixing in
further west. We will likely even see thunder which will only lead
to higher amounts of icing where it occurs. In general, we are
expecting 0.25" to 0.5" of ice accumulation on elevated surfaces
like trees and power lines from Midland/Odessa to Snyder. Roads
will accumulate less ice due to the warm temperatures we saw over
the last week, but still expect major issues and delays by Tuesday
morning. Sleet will mix in with the freezing rain from
Midland/Odessa west and is likely to still cause major travel
issues. Lighter amounts will be seen along the I-10 corridor
tonight, but cold temperatures there will also cause slick
conditions. Have opted to issue an Ice Storm Warning for the
northeast Permian Basin due to the higher ice accumulations and
keep the rest of the warnings and advisories as is. The Hard
Freeze Warning for much of the area for our first freeze of the
season will also continue.
We should see another lull in activity Tuesday afternoon as the
upper low digs further into Mexico. Most locations will not get
above freezing so hazardous travel conditions will continue through
the day Tuesday. The upper low then lifts northeast over the area
Tuesday night into Wednesday with yet another round of
precipitation. Heavy freezing rain and sleet will occur across the
Permian Basin and only add to the likely ongoing issues with travel,
power outages, and tree damage. Further west across SE NM and the
higher terrain of W TX, sleet and snow will be the primary precip
types. Snow totals could reach over half a foot in portions of Eddy
and Lea counties by Wednesday morning. Sleet could change over the
snow even across the western Permian Basin, but amounts would be
much less. Temperatures will warm above freezing on Wednesday
afternoon allowing for much of the ice and snow to melt.
Many cold records will be broken during this event. It is likely we
will see record cold lows today, Tuesday, and Wednesday. We will
also set record cold high temperatures today and Tuesday. The
earliest snow to occur in Midland was a Trace on October 28th 1980.
We will see if that can be beat with this winter storm!
Temperatures return to the 60`s and 70`s later this week just in
time for some Halloween trick or treating.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 28 31 31 50 / 90 80 90 20
Carlsbad 25 31 29 45 / 60 80 70 10
Dryden 37 45 35 65 / 70 50 60 0
Fort Stockton 28 33 30 55 / 70 60 60 0
Guadalupe Pass 18 28 24 39 / 50 80 50 0
Hobbs 23 29 27 43 / 70 80 80 10
Marfa 28 34 23 55 / 30 40 30 0
Midland Intl Airport 28 32 30 51 / 90 80 90 10
Odessa 27 32 28 51 / 90 80 80 10
Wink 29 35 29 53 / 70 70 70 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...Hard Freeze Warning until 9 AM MDT Tuesday for Central Lea
County-Eddy County Plains-Guadalupe Mountains of Eddy
County-Northern Lea County-Southern Lea County.
Winter Storm Warning until 6 AM MDT Wednesday for Central Lea
County-Eddy County Plains-Guadalupe Mountains of Eddy
County-Northern Lea County-Southern Lea County.
TX...Hard Freeze Warning until 10 AM CDT /9 AM MDT/ Tuesday for
Andrews-Borden-Central Brewster County-Chinati Mountains-
Crane-Davis Mountains-Davis Mountains Foothills-Dawson-
Eastern Culberson County-Ector-Gaines-Glasscock-Guadalupe
Mountains Above 7000 Feet-Guadalupe and Delaware Mountains-
Howard-Loving-Marfa Plateau-Martin-Midland-Mitchell-Pecos-
Reagan-Reeves County Plains-Scurry-Upton-Van Horn and
Highway 54 Corridor-Ward-Winkler.
Winter Weather Advisory until 7 AM CDT Wednesday for Crane-Davis
Mountains-Davis Mountains Foothills-Eastern Culberson
County-Loving-Pecos-Reagan-Reeves County Plains-Upton-Van
Horn and Highway 54 Corridor-Ward-Winkler.
Winter Storm Warning until 7 AM CDT /6 AM MDT/ Wednesday for
Andrews-Dawson-Ector-Gaines-Glasscock-Guadalupe Mountains
Above 7000 Feet-Guadalupe and Delaware Mountains-Martin-
Midland.
Ice Storm Warning until 7 AM CDT Wednesday for Borden-Howard-
Mitchell-Scurry.
High Wind Warning until 9 PM MDT Tuesday for Guadalupe and
Delaware Mountains.
&&
$$
44/87/44
Area Forecast Discussion
National Weather Service San Francisco Bay Area
507 PM PDT Mon Oct 26 2020
.SYNOPSIS...A strong and critically dry offshore wind event will
persist over the greater San Francisco Bay Area through Monday
evening while winds will be much weaker to the south. Critical fire
weather conditions will persist in the North Bay Mountains, East Bay
Hills and the Diablo Range into Tuesday where gusty winds will
persist. Elsewhere, winds will diminish for most areas by tonight,
yet dry conditions will persist through midweek. High pressure will
bring sunny and mild to warm days through Friday, but nights will be
cool with low temperatures dropping into the mid and upper 30s for
the interior valleys with 40s elsewhere.
&&
.DISCUSSION...as of 02:36 PM PDT Monday...the SFO-WMC pressure
gradient has relaxed substantially over the last few hours, with
it hovering around 9 mb this afternoon (a far cry from its
overnight value of 16.1 mb). As a result, have observed decreasing
wind intensities all across the interior valleys and coastal
regions this afternoon. Nonetheless, the air mass overhead remains
remarkably dry, with widespread RH values in the single digits
being observed all the way down to the coast. To put that into
perspective, the morning launch of the KOAK sounding measured PWAT
value of 0.14 inches: the daily mean for this date is 0.69
inches.
The culmination of this dry air mass and the breezy surface/near-
surface winds led to an extension of the Red Flag Warning for the
coastal regions and lower valleys until 5PM PDT today. Winds are
expected to pick up again in the North Bay Mountains and East Bay
Hills again overnight tonight and into tomorrow morning and that Red
Flag Warning will remain valid through tomorrow at 5PM PDT.
Thankfully, the local WRF and HRRR are not suggesting winds that
were nearly as strong in the higher-terrain locations as what was
observed last night. While we can definitely expect another round of
strong gusts in the 50-60 mph in some of our +2000 ft stations, the
SFO-WMC gradient will continue to relax as the axis of the upper-
level trough that introduced the cold, dry frontal passage yesterday
will continue to move away from our CWA. Winds closer to sea-
level/at sea-level will experience much calmer winds during this
period. In terms of temperatures, can expect colder min temperatures
in the interior valleys of the North and East Bay, along with
valleys in the Central Coast. The dry, clear air mass will help to
increase the amount of radiation lost to space overnight, while cold
air from the higher-terrain locations sinks down to the valley
floors. As such, min temps in the 35-37 F range are likely to be
observed in those locations. It should be noted, however, that this
air mass is much drier than average. Such an air mass will easily
lose much of its radiational gains during the day. As such, may need
to bring min temps down a by a couple of degrees, especially for the
interior valleys.
Max temperatures for tomorrow will be slightly warmer by a couple of
degrees F that what has been observed today as the axis of the
trough that introduced our current cold, dry air mass exits the West
Coast. As it does so, the axis of the upper-level ridge off the
coast will begin to move over California through midweek. The air
mass will attempt to warm over the interior by a couple of
degrees, but nighttime radiational losses due to the dry air mass
will result in chilly nights in the 40s to low 50s F across much
of the CWA during that timespan. Nonetheless mid-range guidance
does prog the ridge to weaken and make way for another trough that
will initially develop off the coast and then gradually make its
way over California. The good news here is that this trough will
greatly aid in deepening the marine layer during the second half
of the week, helping to gradually restore humidity values across
much of the dried out lower-elevations of the CWA (e.g. return of
low stratus and fog).
It should be noted that one GEFS member does suggest a faint precip
signature Friday night into Saturday morning as the axis of the
trough inches closer to the CWA, no other members on the GEFS or
ECMWF are currently suggesting that there will be enough moisture
in the air mass for this setup to transpire. So for now, can say
that significant signs of any precip are in sight through Election
Day. Long-range GEFS and ECMWF ENS are progging a rather zonal
mid-level flow all across the CONUS through much of next week. On
the plus side, not seeing any substantial offshore signatures in
the extended at this time.
&&
.AVIATION...as of 5:05 PM PDT Monday...Offshore flow has brought a
very dry airmass to the area. VFR conditions through Tuesday.
Northeast winds have decreased significantly today but are expected
to increase aloft after 06Z. Hi-res models show 925 mb winds in
the 30-35 kt range from 03Z through 16Z in the North Bay and the
northern SFO Bay Area while there is less likelihood of stronger
winds mixing down to the surface. Therefore, expect some LLWS
across the Bay Area and northward during this time.
Vicinity of KSFO...VFR through the period. North to northeast
winds to 10 kt. Stronger winds aloft may cause LLWS overnight.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR. Northwest winds 5-10 kt decreasing
after 04Z. East to southeast valley winds after midnight could get
as strong as 10-15 kt through mid morning.
&&
.FIRE WEATHER...as of 11:18 AM PDT Monday...Morning update as the
Red Flag Warning for lower elevations and Santa Cruz Mountains
has been extended through this afternoon. Strong and gusty
offshore winds prevail over much of the San Francisco Bay Area
this morning with the strongest winds in the higher elevations.
Additionally, relative humidity values have fallen into the single
digits and teens across much of the region and will likely remain
critically low through Tuesday. Wind will diminish in the lower
elevations around midday on Monday while another burst of stronger
winds are likely in the higher elevations of the interior North
and East Bay Monday night into Tuesday. High pressure keeps things
dry all week with warm days and cool nights. The marine layer
won`t return until late in the week.
&&
.MARINE...as of 04:51 PM PDT Monday...Winds will continue to
diminish this afternoon and evening over the San Francisco Bays
and along the immediate coastline. Generally light north to
northwest winds will prevail through mid-week aside from some
locally breezy conditions over the northern outer waters. Mixed
seas will continue with a moderate northwest swell and a longer
period southerly swell.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...Red Flag Warning...CAZ006-505-506-508>510-512-513-529
Red Flag Warning...CAZ507-511
&&
$$
PUBLIC FORECAST: Diaz
AVIATION: W Pi
MARINE: AS
FIRE WEATHER: MM
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Area Forecast Discussion
National Weather Service Nashville TN
805 PM CDT Mon Oct 26 2020
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Surface obs this evening show stationary front remains entrenched
along the east side of the Cumberland Plateau, with temperatures
in the 50s across our area but 60s and even 70s in east Tennessee.
Persistent low cloud deck also remains in place over the region
per obs and satellite imagery. Radar shows a well-defined
secondary cold front approaching from the west, and this boundary
currently stretches from just east of Paducah KY to northwest of
Memphis. Front should enter our northwest counties overnight
before stalling, and bring potential for some light rain in that
area per HRRR and CONSShort models. Rest of the cwa should remain
mostly rain free overnight, but fog and drizzle are likely once
again areawide especially after midnight as dewpoint depressions
lower. Have adjusted temperatures based on latest obs and NBM
guidance, and tweaked precip chances just slightly in the
northwest. Enjoy the seasonally spooky weather!
&&
.AVIATION...
00Z TAF DISCUSSION.
MVFR cigs continue for BNA/MQY/CKV with IFR cigs at CSV. Expect
this thick, low cloud deck to remain through the overnight hours.
Hazy/misty conditions will persist at CKV. Periods of MVFR vis
possible in the early morning hours at all terminals with CSV
potentially seeing IFR to LIFR vis.
We should finally begin to see VFR cigs across the area tomorrow
afternoon beginning around 18Z with CSV and elsewhere around
21Z. Winds will remain light and predominantly from the north
through the TAF period.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Shamburger
AVIATION........Adcock
Area Forecast Discussion
National Weather Service Blacksburg VA
945 PM EDT Mon Oct 26 2020
.SYNOPSIS...
A weak cold frontal boundary works into the region tonight before
stalling just to our east later this week. The stalled front will
allow what`s left of now Hurricane Zeta and an incoming of area of
low pressure to push heavy rain into the area during the Wednesday
through Friday timeframe. High pressure returns by Friday afternoon
and carries us into the Halloween weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 945 PM EDT Monday...
Low clouds and areas of dense fog have started to take over back to
our east over the Piedmont and down across the North Carolina
foothills. For that reason opted into a Dense Fog Advisory for these
locations with observations on the ground as well as a healthy plume
of fog billowing up nicely on the GOES-16 Nighttime Microphysics
product. The HRRR and NAMnest have nailed this scenario pretty well
this evening and continue to show a drop in visibility with shallow
moisture overhead through early Tuesday morning. Further west
confidence drops a bit for fog but remains relatively higher on low
clouds. Fog will be a bit more patchy in these areas with the usual
locations across the New and Greenbrier Valley dropping off between
6-12z. Fog will be slow to burn off come Tuesday morning with most
locations seeing visibility improve around 9 to 10am.
Sunshine will be slow to break through thereafter as our cool high
pressure wedge erodes and eventually retreats from the area. With
that said expect another afternoon partly cloudy to mostly sunny
skies with highs in the upper 60s to low 70s out west and low to mid
70s out east.
Low clouds and fog look to return on the heels of a warm front late
Tuesday night into Wednesday morning. The front will be limited with
just a few isolated showers off to the north of the I-64 stretch
back into the SHenandoah Valley. Elsewhere expected partly to mostly
cloudy skies with highs once again the low to mid 70s. Cooler
conditions are expected to the north where the isolated showers
form. Once the front passes to the north it looks to stall out
providing a set of railroad tracks for an area of low pressure
moving in from the west and the eventual moisture of what is now
Hurricane Zeta to move in.
As of 616 PM EDT Monday...
For the most part our cool air wedge from earlier this
afternoon has eroded with some disorganized bands of clouds back
toward our north and west leftover. As a result a fairly nice
evening on tap with many locations west of I-81 and I-77 in the
upper 60s and low 70s. Cooler conditions though remain out east
due to a slower erosion process of the wedge from earlier today
keeping temps steady in the low to mid 60s.
Meanwhile a weak cold front will continue to approach from the Ohio
River Valley spreading additional clouds into the Allegheny
Highlands and Greenbrier Valley tonight. The front will provide weak
forcing but limited moisture for any shower formation. The best bet
for a shower/sprinkle at this point looks to remain across West
Virginia with a 10-15 percent chance of clipping western Greenbrier
County. Elsewhere the trend is for low clouds and areas of fog to
settle back in. This is especially true out east over the Piedmont
and to our north toward the Shenandoah Valley. Locally dense fog is
possible especially with limited dry air advection behind the front.
Once again it may take several hours for the fog to clear out with
most locations not seeing the sunshine until late Tuesday morning or
mid Tuesday afternoon.
Overnight lows will sit close to 50 degrees. Highs by Tuesday
rebound back above average into the upper 60s and low 70s out west
with low to mid 70s out over the Piedmont.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 215 PM EDT Monday...
Moisture axis sets up Tuesday across the southern Ohio Valley,
bringing slight chance pop for areas north of the I-64 corridor.
From there, focus will shift to both Zeta, who will be making
landfall along the LA coast Wednesday night, as well as a cut
off low that forms off of a deep digging trough in the
southern Rockies. Moisture streaming in from return flow ahead
of Zeta`s arrival means that POPs will start to increase quickly
Wednesday night into Thursday. Likewise, Zeta itself is
expected to quickly pick up speed after making landfall, as it
will get picked up by the strong upper level winds associated
with the high amplitude trough passing through the area.
Overall, severe threat looks marginal, besides flooding threats:
that said, an isolated tornado can not be ruled out for the day
Thursday as the environment will be highly sheared. Water wise,
rainfall could be very heavy and persistent thanks to the
tropical moisture enhancing the front that will be moving
through the region. With less evapotransporation to use up
rainfall, we could see some better responses from rivers than of
recent tropical events. Forecast confidence is still not air
tight, as small shifts in hurricane track, trough progression,
as well as cut of low speed can all have big impacts on the
forecast, so plan on additional changes to come.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 215 PM EDT Monday...
Rainfall will be lasting after Zeta`s passage with the cut off
low now projected to follow behind, meaning more rainfall into
Friday. Cold, drier weather arrives in the long term with a
strong cold front pushing through the area Friday night.
Current forecast brings freezing temperatures into the west for
Friday night. Strong, NW winds should slack overnight as high
pressure builds in.
Saturday will remain dry, clear, and cool with an upper level
ridge passing over the region, meaning high pressure will be
in place. As we head into Sunday, another front is expected to
pass through the area. I`ve gone ahead an introduced slight
chance POPs for the afternoon and evening, as some moisture will
be available in the area to help get turned into some fuel for
showers mainly along the west, as well as down into the southern
Piedmont. This second front keeps things cool all the way into
the start of next work week.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
As of 755 PM EDT Monday...
Mainly VFR cigs and vsbys at most of the TAF sites this evening.
Low clouds and fog though look to return overnight into Tuesday
morning. This is already evident on satellite this evening with
MVFR ceilings sliding in from the west thanks to an incoming
cold front form West Virginia. MVFR-IFR ceilings have also been
noted at BLF, LYH, and TNB as well as most of the TAF sites
across central West Virginia. Overall confidence remains high
for IFR- LIFR ceilings and vsbys at most of the TAF sites
through Tuesday morning. The exception to this would be ROA with
low to moderate confidence on LIFR fog through the TAF period.
Overall we still remain under the influence of the cool high
pressure wedge which will retreat come late Tuesday morning into the
afternoon. Besides the wedge we have an incoming cold front with
limited moisture and dry air advection that looks to cross the area
late tonight into Tuesday morning. As a result expect another
morning of fog and low clouds with a slow improvement to VFR cat
KROA, LYH and KDAN by 14-16z. Elsewhere MVFR conditions can be
expected before 17-19z as winds change to the west and southwest
direction Tuesday afternoon. Winds will remain light with VFR
areawide late Tuesday afternoon and evening. Unfortunately, another
round of low clouds and fog look possible for Wednesday morning.
Overall confidence remains high for poor flying conditions through
Tuesday morning into midday.
.Extended Aviation Discussion...
A weak warm front will pass overhead on Wednesday, which may bring
isolated MVFR showers for BLF and LWB, while VFR conditions should
persist elsewhere. Flying conditions will deteriorate late Wednesday
into Thursday as the remnants of Hurricane Zeta combined with a low
pressure system will bring widespread heavy rain and low ceilings to
the region. These conditions are likely to continue through Friday
as the storm system departs. High pressure should return on Saturday
to provide improved flying conditions.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Dense Fog Advisory until 10 AM EDT Tuesday for VAZ034-035-
043>047-058-059.
NC...Dense Fog Advisory until 10 AM EDT Tuesday for NCZ003>006-020.
WV...None.
&&
$$
SYNOPSIS...ET/PW
NEAR TERM...ET
SHORT TERM...RR
LONG TERM...RR
AVIATION...ET/PW
Area Forecast Discussion
National Weather Service Springfield MO
1020 PM CDT Mon Oct 26 2020
.UPDATE...
Issued at 1019 PM CDT Mon Oct 26 2020
No changes in the advisory planned - though we will continue to
monitor for the potential impact during the morning rush hour.
KSGF continues to highlight band of rain moving out of northeast
Oklahoma up the I-44 and Highway 60 corridors this evening
however advance of freezing line has slowed and verification calls
have only detected freezing over higher elevations with no
impacts on roadways. Recent radar trends also shows rainfall
becoming more patchy in nature.
Uptick in coverage and perhaps intensity expected late tonight
into early Tuesday. RAP does show a disconcerting signal for
0.10-0.20 QPF later tonight while HRR/ARW etc maintaining the
more southward axis of the QPF falling on areas where temperatures
are going to be above freezing. Confidence consequently precludes
changes at this time.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 306 PM CDT Mon Oct 26 2020
Widespread precipitation continues across the area this afternoon.
With an elevated warm nose, most precip should fall as liquid
through Tuesday, with surface temperatures being the deciding
factor on ptype in most areas. Surface 32F line is currently from
near Pittsburg, KS to Lamar, El Dorado Springs, Warsaw, and
Versailles in MO and making slow and steady progress south. The
freezing line is expected to hang up along the I-44 corridor
tonight, with temperatures in that area hovering right around 32.
Currently, ice accumulations of a trace to around a tenth of an
inch are forecast along and north of the I-44 corridor, with the
greatest confidence in those amounts being farther to the
northwest where the colder air resides. Right along the corridor,
having temperatures right at freezing in the forecast leads to
greater uncertainty and lesser impacts due to marginal
temperatures and relatively warm ground temperatures. Overall,
messaging is for limited impacts with accumulations mainly on
elevated surfaces.
Temperatures warm Tuesday into the mid 30s northwest to the mid
40s southeast. Another round of rain moves in from the south
during the day.
.LONG TERM...(Tuesday Night through Monday)
Issued at 306 PM CDT Mon Oct 26 2020
A deep upper low will move through the region Wednesday into
Thursday, bringing widespread rain and some thunderstorms
Wednesday afternoon into Thursday. Currently forecasting 1.75-2.75
inches of rain with this event. Highs will primarily be in the 50s
both days.
Rest of the forecast looks dry with highs in the 50s Friday, low
60s Saturday, around 60s Sunday, and the mid 60s Monday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1233 PM CDT Mon Oct 26 2020
Surface freezing line continues to ease eastward toward the I-44
plateau early this evening...bringing the potential for light
freezing drizzle/patchy light freezing rain to the KJLN and KSGF
regions through much of the night. Expectation that the KBBG
though will remain above freezing overnight.
Otherwise...anticipate LIFR/IFR conditions through much of the
TAF period before boundary layer begins to dry out Tuesday
afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Winter Weather Advisory until noon CDT Tuesday for MOZ055-056-
066-067-077-078-088-089.
KS...Winter Weather Advisory until noon CDT Tuesday for KSZ073-097-
101.
&&
$$
UPDATE...Runnels
SHORT TERM...Titus
LONG TERM...Titus
AVIATION...Runnels