Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/03/21
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1053 PM EDT Tue Nov 2 2021
.SYNOPSIS...
A few lake effect snow showers will be possible tonight,
especially in our western Adirondack zones. Otherwise expect
chilly overnight temperatures with most areas experiencing the
first widespread freeze of the season by sunrise. Otherwise,
generally dry, tranquil weather is expected through this
weekend. Temperatures should remain seasonably cool through the
weekend as well.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 10:30pm, a secondary shortwave currently tracking towards
Lake Erie has allowed low and mid-levels winds downstream of it to
shift from the west to the northwest. As a result, radar
imagery hint that the current band extending downwind of Lake
Ontario will start to veer southward over the coming hours. The
HRRR is picking up on this well and was used to adjust the POPs
in the previous forecast. The HRRR continues to suggest that the
disorganized snow showers entering into the chimney of northern
Herkimer County will dissipate over by 03 - 05 UTC allowing a small
window of dry time before the new and potentially more organized
band becomes directed into central Herkimer/Hamilton County. It
is this band where more appreciable snow accumulation up to an
inch could occur through early Wednesday morning. This is on
track with the previous forecast so minimal changes were made to
the current forecast.
Previous discussion...Westerly flow has induced a favorable
fetch over Lake Ontario with westerly flow advecting a chilly
air mass over the relatively warm lake waters. With the delta-t
between the incoming air mass and waters exceeding the 13C
threshold, radar imagery continues to show a disorganized lake
band entering into the chimney of Herkimer and northern Hamilton
County. Temperatures in this region remain in the low to mid
30s with dew points around freezing. Therefore, p-type here is
likely wet snow. However, since the band is so disorganized and
temperatures marginal, any accumulations will likely be limited
to a coating to a few tenths. Elsewhere, skies have turned
mostly clear and winds have become light resulting in
radiational cooling with temperatures already in the upper 30s
to mid 40s. With dew points near or a few degrees below
freezing, these temperatures will continue to drop into the 30s
through the night and we should observe the first widespread
freeze of the season by sunrise. Interestingly, neither Albany
nor Poughkeepsie have recorded 32 degrees or lower so far this
season and a freeze tomorrow morning would tie for 11 latest
first freeze at Albany and 3rd latest for Poughkeepsie. With
this update, we just adjusted morning temperatures a bit to show
most reaching into the upper 20s to near 32 and also adjusted
POPs to account for the lake effect band veering southward
towards central Herkimer County towards 06 UTC as winds aloft
back to northwest.
Previous discussion..With a nose of high pressure building into
our southern zones from the west, low-level flow trajectories
will also become slightly more westerly (versus northwesterly
flow during the day today), so the lake effect precip is
expected to drop back south overnight tonight towards the Mohawk
Valley. After midnight tonight, the main upper-level trough,
which is currently located back near Michigan and Wisconsin, is
expected to move become more neutrally tilted as it moves
towards our region. Additional forcing for vertical motion
associated with this disturbance may lead to some enhancement of
the lake effect shower activity later tonight. Temperatures
over the Adirondacks tonight should fall below freezing, which
will allow for some minor accumulations where snow showers fall.
However, with marginal surface temperatures, not expecting much
in the way of accumulation for the Mohawk Valley. As far as the
rest of the region goes, lows should be around or slightly
above freezing in the valleys with below freezing temperatures
in the higher terrain.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Wednesday morning, the upper trough continues to track eastward
through our area. While moisture looks fairly limited away from
the lake effect areas, cannot rule out a few upslope rain/snow
showers during the morning over the higher terrain of the
southern Greens and/or Catskills. As far as lake effect precip
goes, showers will continue through the early morning with
continued CAA over the lakes. However, high pressure continues
to build into the region during the afternoon, which will cause
low-level winds to weaken. Therefore, lake effect precipitation
will become less organized in nature with decreasing coverage
through the afternoon. Height rises aloft and anticyclonic
vorticity advection behind the departing upper trough will lead
to large scale subsidence tomorrow afternoon. However, with
decent mixing to around 750 mb tomorrow, expecting skies to
become partly cloudy in the afternoon with some cu/stratocu
resulting from daytime heating. Highs will be cooler than today,
with 30s in the high terrain to upper 40s for valley areas.
Tomorrow night looks to be one of if not the coldest nights for
the region since last spring. A 1028 mb surface high is expected
to be centered over or near the region by 12z Thursday. With
this high overhead, expecting temperatures to drop off quickly
after sunset due to a combination of light to calm winds and
mainly clear skies. Many areas that have not yet had a freeze
this fall will likely experience their first freeze tomorrow
night, as even most valley locations will drop below freezing
with many areas dropping well into the 20s, even outside of the
higher terrain.
Thursday starts off chilly with daytime highs only rebounding
into the 30s and 40s again. We will be under the influence of
surface high pressure, so mainly tranquil conditions are
expected. An upper-level trough looks to approach our area, with
a southern stream disturbance sliding out to sea well south of
our area. The upper-level trough could spread some clouds into
the region and may lead to a few showers downwind of the Great
Lakes, but relatively wake low- level winds should prevent
these showers from reaching all but the very far western
portions of our CWA. Otherwise, it will be too dry for any
precip for our area. Thursday night will be another night with
very favorable conditions for radiational cooling as high
pressure and light winds will continue to dominate our weather.
There is a bit of uncertainty as to if there will be any
lingering cloud cover that could prevent temperatures from
dropping off quickly, but if skies do indeed clear then
temperatures could once again drop below freezing for most of
the region.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The theme during the extended forecast period will continue to be
dry and tranquil as a large surface high area remains the dominant
weather feature over the area, and for that matter a vast majority
of the country. Higher heights/flat ridging will build in from the
west during this time period. That said, expect for a day-to-day
bump in temperatures late this week and into the second week of
November.
Temperatures overall will average out near normal levels for the
balance of the period with increases each day. High temperatures on
Friday are forecast to be near 50F. By Thursday of next week, high
temperatures are forecast to be in the mid 50s. As for low
temperatures, Friday night/Saturday morning lows are forecast to be
in the mid to upper 20s. By Tuesday night/Wednesday morning,
overnight lows will be in the upper 30s to lower 40s along the river
valleys (mid 30s higher elevations).
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thu...Skies will clear at the TAF sites through
mid-evening, with several hours of mostly clear conditions
expected through the remainder of the evening into the overnight
hours. Some lake effect clouds may drift across GFL/ALB/PSF late
tonight but it is uncertain whether these clouds will reach as
far east as the Hudson Valley. Even if they reach the Hudson
Valley cloud bases will be above 3000 feet. If skies remain
clear through the night some fog will be possible at GFL, so
there is quite a bit of uncertainty about the sky and vsby forecast
at GFL from 06z through 12z. Sct- bkn cloud cover can be
expected through the day Wednesday with VFR conditions and cigs
from 4 to 6 kft.
Winds will be west-southwest at less than 10 kts tonight, then
westerly increasing to 5 to 15 kts during the day Wednesday.
Outlook...
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
We should remain free of significant precipitation for the next
several days, except for some lake effect precipitation over
portions of the western Adirondacks. RH values have fallen into
the 30-40% range this afternoon for most of the area where no
lake effect precip has fallen, but RH values should rebound to
80-90% tonight. Tomorrow, RH values will fall to 50-60% and will
recover to over 90% tomorrow night.
&&
.HYDROLOGY...
Hydro issues are not expected during the next seven days with
mainly dry conditions expected at this time.
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...Main/Speciale
NEAR TERM...Main/Speciale
SHORT TERM...Main
LONG TERM...Evbuoma
AVIATION...MSE/Rathbun
FIRE WEATHER...Main/Thompson
HYDROLOGY...Main/Thompson
Area Forecast Discussion
National Weather Service Birmingham AL
806 PM CDT Tue Nov 2 2021
.UPDATE...
For 00Z Aviation.
&&
.SHORT TERM...
/Updated at 958 AM CDT Tue Nov 02 2021/
Morning fog has long since dissipated across central Alabama, with
mostly clear conditions prevailing in their wake in most areas.
The exception to this is a narrow band of cloud cover stretching
from near Anniston to Birmingham to Tuscaloosa along a weak
boundary. For the remainder of the day, high pressure will
continue to shift to the east allowing a slightly elevated frontal
boundary to push south through the Tennessee Valley and into
central Alabama later today. Winds will veer to a more northerly
direction in wake of this boundary and locations along and north
of the I-20/59 corridor may struggle to make it above the 60
degree mark as cold air advection will begin to take shape,
limiting heating. Additionally, some cloud cover will start to
filter back into these areas, especially during the afternoon.
Locations to the southeast of this feature across portions of east
and southeast Alabama will remain mostly clear and climb into the
low to mid 70s. The forecast largely remains on track, so only
minor tweaks made to the sky grids based on current obs/trends.
AMP.24/HUN
Previous short-term discussion:
/Updated at 357 AM CDT Tue Nov 02 2021/
Today, Tonight, and Tomorrow.
Broad upper-level troughing is situated across much of the eastern
CONUS this morning with a low amplitude shortwave moving across the
Ohio Valley toward the Mid-Atlantic. This perturbation is producing
enhanced cloud cover and scattered light rain across portions of KY
and TN. Most light rain is stretched generally along an axis of 850
mb frontogenesis observed on recent RAP mesoanalysis. Farther south
across Central Alabama lies a cool/stable airmass, calm wind, and
clear skies - for most. This has fostered development of fog,
particularly along rivers and valleys, and many areas south of the
Alabama River per satellite imagery. We may add HWO mentioning for
reduced visibility through 9 AM this morning, at which time
insolation and mixing will improve the fog situation. Nonetheless,
northerly flow will continue throughout today, though an increasing
presence of mid to upper-level cloud cover will continue in from the
north and west as the tail-end of the aforementioned perturbation
approaches and advances quickly eastward. There could be a few
passing sprinkles this morning as well, mainly in the far northwest.
A ~10% PoP was put in these areas, but no measurable rainfall is
expected.
A zone of confluent, westerly mid-level flow will situate to our
north across the TN and OH Valleys tonight and tomorrow morning,
with the associated surface high spread over much of the central and
eastern CONUS. Thereafter, another transient perturbation is progged
to move from the Central and Southern Plains toward the the TN
Valley, and eventually Southeast. This will provide enough lift along
the lingering 925-850 front to foster scattered light rain and
sprinkles despite ongoing northerly surface winds and PWs <1.0". I
have 20-30% PoPs in areas along and north of I-20 as a result.
Rainfall amounts will be light, but northerly surface winds and
cloudy skies will make for a dreary November day for most. Highs in
the upper 40s to upper 50s are expected in these areas, with warmer
temperatures farther southeast. Some places, such as Eufaula, could
make a run for 70 degrees.
40/Sizemore
.LONG TERM...
/Updated at 302 PM CDT Tue Nov 02 2021/
Only minor updates needed to the long term forecast. Any rain
Wednesday night into Thursday will be very light. There is deep
layer moisture present but lift is weak/sporadic, and
precipitation may be more drizzly in nature if anything.
There is uncertainty for Friday regarding a potential surface low
moving northeastward across the Florida peninsula and whether the
edge of its rain shield will clip our southeast counties. With a
lack of model consistency stuck close to the previous forecast
with just a slight chance of rain in the far southeast. At this
time potential for any widespread frost over the weekend looks low
as dew points/low temperatures have trended upward, but will have
to monitor for any localized potential.
32/Davis
Previous long-term discussion:
/Updated at 357 AM CDT Tue Nov 02 2021/
Thursday through Monday.
Forecast models whiffed on the handling of the system which will
affect the region Wednesday night through Thursday night. The
southernmost shortwave embedded within the large-scale trough is
now expected to have less interaction and phasing with the
northern shortwave. This flatter solution will yield much weaker
isentropic lift, with the possibility that many locations in the
forecast area may not receive measurable rainfall. The chance for
measurable rainfall has been lowered to 40 percent northwest of
I-85, with even lower chances farther south. Temperatures on
Thursday should remain on the cool side under an area of mid-level
cloudiness.
As the weakened trough axis moves through on Friday, decreasing
lift should be insufficient for rain to continue. Behind this
system, surface high pressure and northwesterly mid-level flow
will provide a period of cool and dry conditions lasting through
at least Monday.
87/Grantham
&&
.AVIATION...
00Z TAF Discussion.
A VFR forecast is expected for the next 24 hours with surface
ridging. Clouds will slowly increase aloft tonight into Wednesday
as a broad upper trough swings into E Conus with cigs starting out
as cirrus and lowering to mid level through forecast. Although
there will be a small chance for -RA all all sites but MGM/TOI
through the period, chances are too low to mention at this time.
Otherwise, surface winds will be N/NE 4-8kts through the forecast.
Note: AMD NOT SKED is appended at KBHM due to ASOS power loss until
further notice.
08
&&
.FIRE WEATHER...
Rain-free conditions continue tonight, with a small chance of
light rain across the north on Wednesday. Chances of very light
rain or drizzle continue Wednesday night into Thursday. RH values
remain above 50 percent Wednesday through Friday afternoons
except Wednesday afternoon in the far south.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 41 56 44 55 42 / 0 30 40 30 10
Anniston 44 60 47 57 45 / 0 20 40 30 10
Birmingham 44 56 46 57 46 / 0 20 40 20 10
Tuscaloosa 46 57 45 58 47 / 0 20 30 20 0
Calera 46 59 47 58 47 / 0 20 40 20 10
Auburn 46 65 49 60 47 / 0 0 20 20 10
Montgomery 47 67 50 64 49 / 0 10 20 20 10
Troy 48 69 51 66 49 / 0 0 10 10 20
&&
.BMX WATCHES/WARNINGS/ADVISORIES/...
None.
&&
$$
Area Forecast Discussion
National Weather Service Wichita KS
836 PM CDT Tue Nov 2 2021
...Evening Forecast Update...
.UPDATE...
Issued at 835 PM CDT Tue Nov 2 2021
As of 01z/8pm, water vapor imagery shows an upper level wave cutting
through the Central High Plains, with an associated shield of
stratiform precip extending from western KS into northern OK.
Temperatures have mostly held in the mid to upper 30s over the past
several hours. However, recent obs have shown a subtle drop of a
degree or two over the past couple of hours, mainly from Russell
south through Medicine Lodge. In that area, temps have fallen to
around 34/35. Given the pool of colder air aloft, forecast soundings
suggest this subtle SFC cooling may be just enough for a rain/snow
mix for a few hours as the precip winds down from NW to SE. RAP
forecast soundings actually hint at enough cooling for a brief
change to all snow in the above-mentioned area. Given the lack of
stronger low-level CAA/drying, the RAP`s solution is probably
overdone, but does appear to be handling the SFC temps better than
some other short-term model guidance. Based on all of the above, I
updated the forecast through this evening to reflect a rain/snow mix
where temps have the best chance of falling to near 34 degrees
(south of I-70 and west of I-135). No impacts from wintry weather
are expected.
Martin
&&
.SHORT TERM...(This evening through Friday night)
Issued at 259 PM CDT Tue Nov 2 2021
Water vapor imagery shows an upper impulse approaching the
Southern High Plains with a broad upper trough encompassing the
Great Lakes into the Ohio Valley. At the surface, high pressure
extends across the Upper and Mid Mississippi Valley.
Area of light rain has been increasing across southwest and
southern KS over the last few hours as mid level theta-e advection
and isentropic lift increases ahead of the approaching shortwave.
Not much is expected to change early this evening with light rain
remaining in place with a gradual southeast shift to rainfall as
the overnight hours progress. Toward sunrise, only far southern
KS is still expected to see precip as the upper energy sinks into
the Southern Plains and Ozark region. Rainfall amounts are
generally expected to be around a quarter inch or less.
By Wed afternoon, northwest flow aloft will be in place across the
Plains with the better precip chances pushed well southeast of the
forecast area. Should still see plenty of cloud cover Wed which
keep temps in check again as they top out in the 40s. Not much is
expected to change for Thu with northwest flow remaining in place
and the surface high shifting slowly east as some lee troughing
develops. This will allow for temps to moderate some Thu with
highs getting back into the 50s with increased sunshine.
There is good model agreement in some weak shortwave energy
tracking out of the Northern Rockies and into the Northern Plains
for Fri. This will increase Lee troughing across the area along
with warm advection. So for Fri we are looking for highs to
finally get back closer to seasonal normals with breezy south
winds.
.LONG TERM...(Saturday through Tuesday)
Issued at 259 PM CDT Tue Nov 2 2021
ECMWF and GFS agree on upper ridging overspreading the area on
Sat with a broad area of southwest flow aloft building-in for Sun.
This will setup dry conditions over the weekend with temps close
to or a few degrees above seasonal normals. Will maintain a dry
forecast through Tue as the better upper dynamics remain well
north of the forecast area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 654 PM CDT Tue Nov 2 2021
* MVFR/IFR conditions likely through at least WED AM
* RA/SN mix possible this evening (central/south-central KS)
The upper level wave responsible for the ongoing area of light to
moderate precipitation will continue to slowly move ESE through
tonight, eventually shifting east into the Ozarks by Wednesday
afternoon. Until that time, areas of mostly -RA will continue to
impact portions of central/southern KS. Temperatures aloft are
supportive of wintry precip, but surface temperatures are much
less supportive. For the most part, this should keep the threat
of wintry precip low. However, through about 06z/WED, surface
temps may cool enough for a RA/SN mix across parts of central and
south-central KS. No snow accumulation is expected. The precip
will gradually end from west to east late tonight/early WED AM,
but low CIGs and BR/DZ may linger for several more hours. CIGs
may begin to rise during the day Wednesday, with some slow
clearing possible by late in the day. However, in these types of
setups, low clouds tend to be slower to clear, and I opted to go
more pessimistic with clearing/rising CIGs. It`s possible MVFR/IFR
CIGs will linger into Wednesday evening.
Martin
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 38 45 35 53 / 80 10 0 0
Hutchinson 37 44 34 53 / 60 10 0 0
Newton 38 45 35 53 / 50 10 0 0
ElDorado 39 46 35 52 / 60 10 0 0
Winfield-KWLD 39 46 36 53 / 90 20 0 0
Russell 36 44 32 58 / 30 0 0 0
Great Bend 34 44 32 56 / 60 10 0 0
Salina 39 46 34 56 / 20 10 0 0
McPherson 38 45 34 53 / 40 10 0 0
Coffeyville 41 48 34 54 / 80 30 0 0
Chanute 39 47 33 53 / 40 20 0 0
Iola 38 47 33 53 / 30 10 0 0
Parsons-KPPF 39 47 33 53 / 60 20 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RM
SHORT TERM...RBL
LONG TERM...RBL
AVIATION...RM
Area Forecast Discussion
National Weather Service Lincoln IL
743 PM CDT Tue Nov 2 2021
.SYNOPSIS...
Issued at 734 PM CDT Tue Nov 2 2021
Chilly fall weather is expected across central Illinois for the
next several days before a big warming trend takes place over the
upcoming weekend.
&&
.UPDATE...
Issued at 743 PM CDT Tue Nov 2 2021
A short-wave trough evident on 0030z/730pm water vapor imagery
over the Oklahoma/Texas panhandles continues to spread clouds and
showers into the Ozarks this evening. The northern edge of the
cloud cover is streaming across south-central Illinois...mainly
along and south of a St. Louis, Missouri to Vincennes, Indiana
line. Based on satellite trends and RAP/NAM RH progs, think a high
overcast will persist south of I-70 overnight, while skies will
become clear further north across the remainder of the KILX CWA.
Given clear skies, a dry boundary layer, and winds becoming nearly
calm...excellent radiational cooling will allow lows to bottom out
in the middle to upper 20s across much of the area...with readings
near 30 degrees across the far south where high clouds will be
most prevalent. Aside from a few tweaks to hourly temps, current
forecast is on track and requires no major updates at this time.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 158 PM CDT Tue Nov 2 2021
Diurnal cumulus began forming around midday, with the RAP model
eroding it from the west through late afternoon. After that, most
of the forecast area should be clear overnight, through there is
some question as to the arrival of some cirrus south of I-70.
Latest satellite imagery shows the northern edge around St. Louis
and tracking southeast, with several of the models keeping high-
level moisture confined to southern Illinois overnight. The
northern extent would have implications as to whether or not the
southeast CWA sees temperatures below freezing tonight. This would
be a close enough call that a Freeze Warning still seems warranted
there, and will issue one as far north as a Taylorville to Paris
line. From about I-72/Danville north, there was a widespread
freeze this morning, and in coordination with neighboring offices,
no further frost/freeze headlines will be done for that area this
season.
Temperature-wise on Wednesday, highs should be close to today,
with upper 40s prevailing.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 158 PM CDT Tue Nov 2 2021
Sprawling high pressure will continue to dominate our weather the
remainder of the week, only slowly pushing east. Some gradual
improvement in temperatures is expected late week as winds turn
southerly, and highs in the 60s should return on Sunday as upper
level ridging builds into the central U.S.
No precipitation is expected the next 7 days. A couple fast
moving shortwave should pass by Friday and Saturday, but will be
moisture starved due to a developing storm system in the northeast
Gulf.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 635 PM CDT Tue Nov 2 2021
VFR conditions will prevail through the entire 00z TAF period.
Diurnal Cu at around 6000ft will continue to dissipate over the
next couple of hours followed by mostly clear skies through the
night. NAM layer RH progs suggest a band of mid-level cloudiness
will skirt across north-central Illinois Wednesday afternoon,
potentially creating BKN-OVC conditions at around 15,000ft at both
KPIA and KBMI after 18/19z. Further south, only FEW-SCT diurnal Cu
at around 6000ft will develop. Winds will be NW at under 10kt
through Wednesday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight tonight to 9 AM CDT Wednesday for
ILZ052-054>057-061>063-066>068-071>073.
&&
$$
UPDATE...Barnes
SYNOPSIS...Barnes
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Barnes
Area Forecast Discussion
National Weather Service North Platte NE
615 PM CDT Tue Nov 2 2021
.SHORT TERM...(This evening through Wednesday night)
Issued at 326 PM CDT Tue Nov 2 2021
A bank of stratus stretching northwest to southeast across wrn and
scntl Nebraska should lift north into ncntl Nebraska tonight. This
is the result of a weak Pacific front moving into wrn Nebraska. The
front will progress slowly east Wednesday and be located over ern
Nebraska by Thursday morning.
It looks like the moisture ahead of the front will be deep enough
for patchy drizzle across ncntl Nebraska tonight. This is supported
by the NAMnest reflectivity product but only weakly suggested by the
NAM12, RAP and HRRR model reflectivity`s. Temperatures are very
marginal for freezing drizzle. In fact, the short term models keep
ncntl Nebraska above freezing tonight. Once the clouds move in, the
radiational cooling process will be halted and given the warm ground
with soil temperatures in the lower 40s according to the Nebraska
Climate Office, the cooling process could even reverse with warming
occurring.
The fog situation tonight favors wrn Nebraska for development where
a push of dry air will move in overhead. This dry h850mb air should
enhance the radiational cooling process at the sfc. Melting snow
will provide a moisture flux. Areas of fog are in place across much
of wrn Nebraska and the fog forecast leans on the short term model
blend visibility product.
The SREF and HREF both show clearing skies from west to east
Wednesday. By late afternoon, both models show the stratus across
ern and scntl Nebraska. The temperature forecast uses the short term
model blend plus bias correction for highs in the 40s to lower 50s.
This forecast is near the 50th percentile of the NBM which is
cooler than the guidance blend by a few degrees.
The models are in very good agreement continuing warm air advection
Wednesday night. By Thursday morning, temperatures at h850mb should
be around 7C. Upper 20s are in place for lows using the short term
model blend but the guidance blend suggests mid 20s across wrn
Nebraska and lower 30s across ncntl Nebraska. There is also the
potential for valley fog according to the HREF visibility product.
These forecast details might be best revisited with later
forecasts.
.LONG TERM...(Thursday through Tuesday)
Issued at 326 PM CDT Tue Nov 2 2021
Dry weather is predicted Thursday through Tuesday. Two sfc low
pressure systems will move ashore and track through central Canada
during the period Thursday through Sunday. The associated upper
level trofs will tap warm air across the Desert Southwest leading
to an extended warm spell across wrn and ncntl Nebraska. The
warming trend will lead to h850 temperatures in the upper teens by
Saturday and highs, theoretically, in the 70s, both Saturday and
Sunday. The official forecast is modest with highs in the 60s to
around 70. Look for a temperature mark up with later forecasts;
the GFS and ECM guidance suggest 70s. A check on high cloud
potential indicates a baroclinic leaf may developing across the
nrn Plains next weekend. If this is correct, then mostly clear
skies and nearly full sun would prevail across Nebraska.
High temperatures drop Monday and Tuesday. This is the result of the
second low pressure system dropping a cold front into Nebraska. Both
the ECM and GFS guidance suggest highs in the 50s and 60s these days
which is still above average for November. Both models then show a
significant storm system affecting the Great Plains later next week
but the predictability of the storm is too low. Check later
forecasts; it is not unusual for a strong storm system to follow a
period of mild weather.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 615 PM CDT Tue Nov 2 2021
Stratus, and potentially fog, are the primary aviation weather
concerns for western and north central Nebraska. MVFR ceilings
will likely lower to IFR overnight for southwest terminals
(including LBF), while patchy fog will affect most of the region.
Winds transition to southwesterly Wednesday morning, helping to
pull in drier air and lift the clouds through the day.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
AREA FORECAST DISCUSSION
National Weather Service Morristown TN
1056 PM EDT Tue Nov 2 2021
.UPDATE...
EVENING UPDATE.
&&
.DISCUSSION...
No significant changes for the evening update. Low clouds remain
in the TN valley and high clouds are beginning to move in from the
west elsewhere. Upped cloud cover overnight to align with
satellite trends and the 01z HRRR which seems to have a very good
handle on the lingering low level cloud cover. This could have
implications on overnight temperatures as clouds move in and
moderate low temps, especially in the freeze warning areas.
That being said, LNP up in Wise county VA is already reporting
freezing temps, and higher elevations elsewhere are probably
seeing similar values. As such, can`t see any reasons to adjust
current headlines and will leave them as-is. No other changes
necessary.
CD
&&
.AVIATION...
00Z TAF DISCUSSION.
Flight categories should remain VFR through the period. Low clouds
will likely hang on through much of the night at KTRI, and
possibly KTYS if they continue building west off the mountains.
Otherwise, another incoming disturbance will spread mid clouds
across all sites by daybreak or shortly thereafter, with some
ISOLD to SCT SHRA getting into the southern TN valley after 18z.
Confidence not high enough to include prevailing SHRA, so just
included VCSH for now.
CD
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 43 52 43 53 39 / 0 20 30 20 10
Knoxville McGhee Tyson Airport, TN 38 52 41 52 36 / 0 10 30 30 10
Oak Ridge, TN 38 52 39 53 35 / 0 10 30 20 10
Tri Cities Airport, TN 32 51 37 50 31 / 10 10 30 30 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Frost Advisory until 10 AM EDT /9 AM CDT/ Wednesday for Bledsoe-
Campbell-Claiborne-Grainger-Hamblen-Jefferson-Morgan-North
Sevier-Northwest Cocke-Northwest Greene-Scott-Union.
Freeze Warning until 10 AM EDT Wednesday for Blount Smoky
Mountains-Cocke Smoky Mountains-Hancock-Hawkins-Johnson-
Northwest Carter-Sevier Smoky Mountains-Southeast Carter-
Southeast Greene-Sullivan-Unicoi-Washington.
VA...Freeze Warning until 10 AM EDT Wednesday for Lee-Russell-Scott-
Washington-Wise.
&&
$$
Area Forecast Discussion
National Weather Service Tulsa OK
839 PM CDT Tue Nov 2 2021
...UPDATE...
.DISCUSSION...
A short wave will continue to push into the area tonight with lift
in the form of a healthy amount of isentropic ascent ahead of the
wave aiding in widespread shower activity across E OK and NW AR
currently ongoing. PWAT analysis shows a pocket of 1"+ south of
I-40 across E OK. This is relatively high for this time of year
and will coincidentally be a location to watch for our marginally
higher totals overnight. This is also a location where marginal
amounts of MUCAPE (possibly around 100J/kg) could move in allowing
for some isolated convective properties within the widespread
stratiform rain. The threat is incredibly low but a strike or two
of lightning across far SE OK can`t be ruled out. Rain rates will
generally be between one tenth and one quarter of an inch though
locations across SE OK could possibly see brief periods with rates
around one half inch per hour.
NW AR (namely the higher terrain - above 2000 feet - of eastern
Carroll and Madison) may be a location to watch for some brief
wintry weather in the morning. The latest RAP and hi-res guidance
is coming in a tad warmer at the 925mb level in an already
marginal setup for a few snowflakes with temperatures only
expected to dip into the upper 30s (some mid 30s are possible on
the peaks). Some personal weather stations within the higher
terrain are currently reading 39 at the time of writing. The dew
point will need to be watched as cloud cover and continued
precipitation through the night will likely keep the dew point
elevated and temperatures elevated. This will, in turn, keep
wetbulb effects in check. The vast majority of guidance suggests
the dew point falls right around sunrise which would be the time
the atmosphere could allow for a brief period of a few snowflakes
to show themselves. RAP soundings for late tonight/early tomorrow
morning show a deep saturated profile through the night with
temperatures straddling the 0C isotherm from about the 800mb level
to about the 900 to 925mb level before noticeably warmer
temperatures dominate toward the surface. With a pocket of warm
temperatures from the surface to 925mb, a long period of
temperatures right around 0C in the aforementioned layer with no
noticeable dip to -1 or -2 C (this will allow for snow initially
falling to warm as it descends to near freezing before melting as
it descends through 925mb to the surface), and a shallow dendritic
growth layer between 15.8kft and 18kft, wintry precipitation
looks unlikely thus will keep the light rain/snow wording out of
the forecast. With that said, we can`t rule out a few small wet
snowflakes being spotted across the highest peaks in Madison and
Carroll counties. Accumulations are not expected. Any
precipitation ongoing tomorrow morning will quickly diminish by
mid to late morning when the upper short wave quickly moves out of
the area.
As for forecast adjustments, everything appears to be largely on
track though PoPs and temperatures may be adjusted a little in
the short term. Look for the next forecast package update
scheduled by 945PM.
Snider
&&
.PREV DISCUSSION... /Issued 640 PM CDT Tue Nov 2 2021/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Widespread light to moderate rain will continue to overspread the
terminals this evening and gradually end from northwest to
southeast late tonight through Wed morning. Ceilings will lower
into prevailing IFR conditions overnight with only slow
improvement tomorrow. Drier air pushing into western AR may allow
these terminals to show the initial improvement though uncertainty
remains on both the timing and extent of any clearing.
PREV DISCUSSION... /Issued 256 PM CDT Tue Nov 2 2021/
DISCUSSION...
Widespread showers are expected overnight tonight as a shortwave
approaches the area. The showers will be ending fairly quickly
Wednesday as the shortwave passes, but low cloudiness will be slow
to clear.
Drier low level air will try to advect into the area from
northeast Wednesday night, with the far eastern part of our
forecast area being the most likely place to see any clearing.
Thus will issue a freeze watch for that area for late Wednesday
night and early Thursday. Cloudiness will finally erode sometime
in the Thursday through Friday time frame, and if skies do clear
enough, freeze headlines may be needed Thursday night into early
Friday as well in some places.
Dry weather with a warming trend will prevail Friday into early
next week, with temperatures rising back to above normal levels.
It is the time of year that afternoon high temperatures warm above
the National Blend of Models forecast on any sunny day, and have
followed this trend Friday into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 42 48 42 56 / 100 40 0 0
FSM 44 47 38 58 / 90 60 0 0
MLC 44 48 42 56 / 90 40 0 0
BVO 40 48 41 55 / 90 30 0 0
FYV 39 46 34 54 / 90 50 0 0
BYV 38 45 31 54 / 80 50 0 0
MKO 43 47 41 55 / 90 40 0 0
MIO 39 48 37 54 / 70 30 0 0
F10 43 48 42 56 / 90 30 0 0
HHW 45 48 42 56 / 90 60 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...Freeze Watch from late Wednesday night through Thursday morning
for ARZ002-011-020.
&&
$$
SHORT TERM...21