Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/31/19
Area Forecast Discussion
National Weather Service Gray ME
932 PM EST Wed Jan 30 2019
.SYNOPSIS...
An Arctic cold front will cross the region this evening bringing
snow squalls and very gusty winds. Behind this front...very cold
air will move into the region upon gusty west winds resulting in
dangerously low wind chills. This cold weather is expected to
continue for the remainder of the week before moderating
temperatures arrive this weekend along with a few snow showers.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
930 PM Update...Arctic front now nearing the coast. Robust snow
squalls continue along the boundary roughly from Cumberland
County ME northward to Kennebec County. Snow squall warnings are
in effect. In addition, light snow aided by a secondary SFC low
over the Gulf of ME is affecting the mid coast. Have updated the
PoPs and weather over the next few hours to reflect trends. The
activity will sweep offshore within the next couple of hours
followed by bitterly cold winds and clearing skies.
615 PM Update...Have updated the forecast for the next few
hours, mainly for minor changes in temperatures, winds and PoPs
to account for latest trends in observational data. Snow squall
activity will mainly be confined to southern NH over the next
hour or two. A few squalls may still be possible elsewhere along
arctic front also (with KMPV going 1/4 +SN recently). Will
therefore have to watch for echoes appearing as the move out of
VT. Otherwise, the meaty snow squalls have been confined to
southern New England for the most part.
Previously...
Arctic Front will bring Snow Squalls and Very Gusty Winds
this Evening...
High Impact Weather Potential: Snow squalls and strong winds this
evening followed by gusty winds and bitterly cold wind chills
overnight.
Pattern: Early afternoon water vapor imagery reveals impressive gyre
at H5 centered over the western Great Lakes with spokes of energy
rotating around it. The first cleared our area this morning and was
responsible for the snow overnight. The second is an embedded
shortwave collocated with a rapidly advancing arctic cold
front...now moving into western New England. Through the near and
short term forecast period...the low at H5 will continue to march
east...with an arctic airmass arriving and remaining overhead.
Forecast concerns center around the cold frontal passage and
associated wind/squalls this evening followed by wind chills and
mountain snow shower activity.
Through this evening: Arctic boundary and associated line of snow
squalls is now over eastern New York and rapidly moving east.
Band is well captured by today`s high resolution HRRR and
HREF...and expect it to arrive along the CT Valley right around
5pm...marching east and reaching the midcoast around 10pm.
Sounding profiles are very impressive along the front...with
mixed layer depths reaching over 10kft. Winds at 5kft reach
roughly 40kts and suggest an upper bound to llevel wind gusts as
the band moves through. Given the very short period of marginal
advisory-level winds at the surface...have opted to not issue a
wind advisory and rather watch conditions unfold and let the
evening shift follow up with snow squall warnings as
appropriate.
Tonight: Line of snow showers and squalls should clear our eastern
zones between 10 and 11 pm with a blustery and cold night ensuing as
T8s continue to fall to around -25C overnight /-2 to -3 sigma below
climatology/. Expect skies to clear and will favor a consensus
blend as MOS tends to struggle to temps quite cold enough in these
strong CAA regimes. This leads to very little change in inherited
values with lows in the single digits above zero along the
coast...with 0 to -10 over the foothills and mountains. Wind chill
headlines look good based on criteria with no changed needed this
afternoon in collaboration with Caribou.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
High Impact Weather Potential: Continued low wind chills.
Deep...cold cyclonic flow continues through the short term forecast
period...but with generally quiet conditions as the cold airmass is
necessarily dry. Primary feature of note is another vort lobe
rotating around the eastward-propagating H5 low which should bring an
uptick in forcing for ascent and thus some mountain snow shower
activity.
Thursday: Aforementioned vort lobe will spread increasing forcing
for ascent over the region in the afternoon...and therefore expect
some increase in clouds and snow shower activity where there is some
llevel upslope assistance. Elsewhere...expect a mostly sunny day.
T9s in the -18 to -20C range will keep temperatures from moving all
that far during the day...with consensus highs in the teens along
the coast and single digits along and north of the mountains.
Thursday night: Mountain snow shower activity should maximize in the
evening...but then wane overnight as we enter subsidence region
behind departing vortmax. Little in the way of llevel temperature
advection...along with continued mixed boundary layer conditions and
modest surface winds should yield another night of temperatures very
similar to the night previous...single digits along the coast and -5
to -10 in the foothills and mountains. Given these temperatures
and residual westerly winds fully expect that we/ll need
additional wind chill advisory headlines...although overnight
wind chills do not look to be quite as cold and the previous
night.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Ensemble and deterministic model solutions are in decent
agreement on the long wave pattern through late next week. The
persistent pattern of west coast ridge and eastern trough will
temporarily breakdown this weekend and early next week before
returning for the latter portion of the forecast period. The
upper trough temporarily lifts out this weekend and early next
week offering a respite from the bitter cold and a period of above
normal temperatures. However...the upper ridge quickly
reestablishes itself along the west coast of the CONUS with a
downstream trough across much of the remainder of the country. In
the dailies...a weak disturbance brushes by to our south on Friday
leaving us under ridging and cold dry air. High pressure builds
by to our south Friday night and Saturday. A cold front will sag
south into the area with clouds and a few snow showers Saturday
night and Sunday. This boundary will return north as a warm front
on Monday. Low pressure over the Great Lakes will pull a trailing
cold front across the region on Tuesday. Low pressure and its
associated frontal system approach from the Great Lakes on
Wednesday.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term...
Summary: An arctic cold front will move through the region this
evening followed by a prolonged period of dry west and
northwesterly flow.
Restrictions: VFR all sites except RKD/HIE which will be
improving over the next 1-2 hours. VFR will dominate the TAF
period outside of a 1-2 hour period this evening when a band of
snow showers/squalls and strong westerly wind gusts moves
through the terminals. Wind gusts over 30kts are possible with
the line of squalls.
Winds: Westerly winds are strengthening to 12G22kts at the
moment and will continue through this evening...with a period
of stronger winds /mentioned above/ as the front and associated
squalls moves through the terminals. Winds diminish to around
10kts behind this front from the west...but then strengthen
again to 10-15G20-25kts from the west during the day Thursday.
Thursday night...winds diminish to less than 10kts from the
west.
LLWS: No LLWS expected through Thursday night.
Long Term...
Sat - Sun...Sct MVFR in -shsn.
Mon...MVFR in -shsn/-shra with lcl IFR psb in cigs.
&&
.MARINE...
Short Term...
Gales out for all waters with freezing spray advisory beginning
overnight as temperatures cool behind departing Arctic front. As
the front passes in the 6-10pm timeframe...gusts over 40kts will be
possible as snow squalls move over the waters. Winds will gradually
diminish behind the front...but gales will continue in the outer
waters through the end of the short term forecast period.
Long Term...
Fri - Sat...SCA`s likely outside the bays.
Mon...SCA`s psb outside the bays.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Wind Chill Advisory until noon EST Thursday for MEZ007>009.
NH...Wind Chill Advisory until noon EST Thursday for NHZ001>009-011-
015.
MARINE...Freezing Spray Advisory until noon EST Friday for ANZ150>154.
Gale Warning until 4 AM EST Thursday for ANZ151-153.
Gale Warning until noon EST Friday for ANZ150-152-154.
&&
$$
NEAR TERM...Ekster
SHORT TERM...Arnott
LONG TERM...Schwibs
AVIATION...Arnott/Schwibs
MARINE...Arnott/Schwibs
Area Forecast Discussion
National Weather Service Huntsville AL
901 PM CST Wed Jan 30 2019
.NEAR TERM...(Tonight)
Issued at 901 PM CST Wed Jan 30 2019
Early this evening, surface high pressure originally from the Arctic,
building SE-ward across the Mid Mississippi Valley, was helping to
prolong our on-going cold snap. After earlier high temperatures into
the mid/upper 30s most spots, 8 PM readings have cooled into the
mid/upper 20s with light NW-N winds. Even lower dewpoint values,
ranging from the lower single digits over parts of NW Alabama and
southern Middle Tennessee, to the mid/upper teens across NE Alabama.
A few dewpoint values at and below zero Fahrenheit have been noted
over parts of NE Mississippi and middle Tennessee in the late
afternoon and early evening.
The above noted high should continue building to the SE, which should
result in light NW-N winds becoming NE-E overnight, and then SE on
Thursday. Before a SE component is realized on Thu, another very cold
night is expected across the valley. Low temperatures should chill
into the mid/upper teens. An area of scattered/broken mid-altitude
clouds extending from the western Ohio River Valley, southward along
the Mississippi could move over the region in the overnight. The
passage of those clouds could help raise low temperatures a couple of
degrees; by diminishing radiational cooling somewhat by slowing
long-wave radiation return back into space. Forecast soundings from
the RAP and NAM both indicate short-term higher relativity humidity
values in the 5000-13000 ft ASL, passing by in the night.
The forecast inhearted from the day crew is in good shape. No major
adjustments were needed.
.SHORT TERM...(Thursday through Friday)
Issued at 247 PM CST Wed Jan 30 2019
An abrupt airmass change will occur Thursday into Friday as the core
of cold air shifts east from the Great Lakes and OH valleys, with low
level flow turning southwesterly over much of the southern Plains
through the Gulf states. Temperatures at 850 mb will go from -7 to
-12C this evening to -3 to 0C by Thursday afternoon.Expected highs
should reach the m-u40s for most valleys, while the Plateau hits
the u30s.
While the region remains in WNW flow at 5h through Friday, a narrow
warm/moist conveyor belt will develop from TX through the OH valley
Thursday night into Friday morning. This seems to shift a bit further
north on Friday as low level ridging will be in place from the mid
Atlantic through GA and AL. The far northwest part of our CWA may be
clipped with light rain, although the ECMWF is coming in dry through
Friday afternoon. Will keep most of the area dry with highs in the
l-m50s as 8h temps warm into the 3-5C range. May keep a sliver of a
slight chance PoP in our far northwest portion AL and southern middle
TN.
.LONG TERM...(Friday night through Tuesday)
Issued at 247 PM CST Wed Jan 30 2019
The energy with the disturbance to our north dissipates amd moves
off the eastern seaboard Friday night. Upper level level ridging
builds over the area as well. At the same time, a stronger shortwave
trough axis moves east into central/eastern Texas. Strengthening
southwest flow near the surface occurs in response. This along with
lingering cloud cover should keep low temperatures a bit warmer, in
the mid 30s to lower 40s.
As this shortwave moves east on Saturday into Louisiana and Arkansas,
even stronger warm air advection and some moisture advection will
occur over the Tennessee Valley. At this time, NAM12 may be too
aggressive with the eastward progression of precipitation. Therefore,
held even isolated precipitation out of the forecast on Saturday.
With continued warm air advection (strongest west of I-65) ahead of
the shortwave, despite fairly widespread cloud cover, think highs
will reach the upper 50s to lower 60s on Saturday.
By Saturday evening, synoptic models differ on whether this
shortwave weakens significantly or not. However, most introduce
isolated rain showers to the forecast just south of the Tennessee
River, with higher chances of precipitation further south in central
Alabama (closer to the upper level disturbance). Most guidance keeps
the main forcing with this upper level energy over southern Mississippi
or Alabama as the disturbance moves east overnight Saturday. Thus,
only keeping only 20 to 30 percent rain chances over the area,
expecting the bulk of this forcing and moisture to remain south of
northern Alabama.
Models show additional ripples of weaker energy moving east through
Mississippi and into the area through the remainder of the weekend,
keeping isolated to scattered rainfall a possibility. Even stronger
southwesterly flow develops Sunday through Monday, as a stronger
storm system develops over the Midwest region and begins to push east
towards the Tennessee Valley area through Monday. This will continue
a significant warming trend with highs climbing into the mid to
upper 60s and lows into the upper 40s to lower 50s in many locations
by Monday. Rain chances will increase ahead of this approaching storm
system Sunday night and continue into Monday. Thunderstorms look
possible on Monday, ahead of the front trailing southeast through the
area, but left out of forecast for now.
The rest of next week looks warmer and wetter with some thunderstorms
possible Tuesday into Wednesday ahead of another stronger storm
system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 548 PM CST Wed Jan 30 2019
Cold surface high pressure situated over the Mid Mississippi Valley
will build to the ESE, moving across the Mid Atlantic region on Thu.
A light NNE flow rounding that high will affect the terminals
tonight. NE winds will veer to an easterly component around daybreak
Thu, then become SE in the afternoon into the 4-8kt range. VFR
weather will continue, with a few passing mid/high altitude clouds.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...RSB
SHORT TERM...17
LONG TERM...KTW
AVIATION...RSB
For more information please visit our website
at weather.gov/huntsville.
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
956 PM EST Wed Jan 30 2019
.UPDATE...
Issued at 956 PM EST WED JAN 30 2019
Some light returns have begun to show up in the Cumberland Basin
region on radar in the last hour or so. Recent runs of the HRRR as
well as other Hi-Res models have trended down even further with
snow amounts associated with this upper level disturbance into the
overnight. Therefore, it is possible that the southern portion of
the area will only see very light amounts as the disturbance
weakens over eastern Kentucky. Have thus adjusted PoPs to follow
these trends. Current temperatures are in the single digits in the
north and in the low teens in the south. A gradual decrease to
mostly single digits, with some below zero values in the north,
still remains on track through dawn. Other than adjusting sky and
PoPs, merely ingested latest observations to freshen up
temperatures, dew points, and winds. A new ZFP was sent. Updates
have also been sent to NDFD and to the web.
UPDATE Issued at 710 PM EST WED JAN 30 2019
Currently watching as an upper level disturbance brings some
light snow showers from Missouri and southern Illinois into
western Kentucky early this evening. Expecting this to move across
the Commonwealth this evening, bringing anywhere from a coating
to perhaps a half of an inch of snow in the southern portion of
our area. However, the most recent run of the HRRR has trended
downwards in snowfall amounts compared to previous runs. Have
updated the forecast to better account for this. Current
temperatures range from around 4 degrees in the north to upper
teens in the south. These temperatures will plummet overnight into
the single digits with areas in the north seeing below zero
values. A new ZFP was not needed at this time. Updates have been
sent.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 429 PM EST WED JAN 30 2019
Current conditions across the area feature high pressure
descending on the region as the Arctic airmass takes hold of the
area. With a decreasing gradient into tonight, winds will be on
the decrease. Thus will expect some light winds and while wind
chills will not quite as low, the clear skies in the north and
snow on the ground will allow temps tonight to plummet into the
single digits near zero and even some negative single digits for
low temps tonight. As for the Wind Chill Advisory, will let it go
this evening as the winds have subsided. Late tonight, another
weak trough rounds the base of the upper level trough as it tracks
across the southern edge of the high. This feature will bring
another shot of light snow to the southern portion of the CWA.
Models show some QPF with this feature and given the Arctic
airmass in place with ratios around 25 to 1, a few isolated areas
of an inch of snow in the south are certainly possible. Mainly
will be expecting a dusting to a half an inch. One factor is the
mentioned loosened gradient and thus less winds. This will mean
less blowing snow with this feature. Have decided to address the
cold and the snow expected in the south with an SPS.
Heading into the day tomorrow, the mentioned disturbance will exit
by mid morning. The coldest low temperatures of the season
tomorrow morning will warm into the 20s in the north and even into
the lower 30s in the south. Thus temps will head into tomorrow
night with some temps in the north below freezing. With this in
mind, ground temps will be quite cold with the next disturbance
moving into the area. Models bring another weak trough through the
area in the midst of the weakening long wave trough as WAA brings
some warmer air into the area. Thus, will expect some snow and or
rain and freezing rain transitioning to all rain later in the day
on Friday. With the cold ground in place, there may be a few
issues with freezing rain in the north and west part of the CWA.
This may pose an issue, so will keep this in the HWO.
.LONG TERM...(Friday through Wednesday)
Issued at 329 PM EST WED JAN 30 2019
The extended period begins with a surface high exiting eastern
Kentucky and a surface low pressure moving into the region Thursday
night into Friday. This low will bring a weak disturbance to the
area, resulting in light snow chances initially, then a period of
light freezing rain possible, followed by a changeover to rain by
the afternoon with minor accumulations possible. Road temperatures
will be below freezing initially, so liquid precipitation could
cause some brief slick conditions. The GFS and the European are
quicker to bring the precipitation in, while the NAM is a bit
slower. After that, high pressure moves back in to the area,
clearing out some clouds and allowing warm air to advect in,
bringing a moderation in temperatures.
Warm weather will be the story from Saturday night onward as a
upper level ridge amplifies over the eastern CONUS. This will
allow high temperatures to reach the 60s from Sunday onward, with
overnight lows generally in the 40s. Rain chances will return
Monday, but models are generally all over the place with
potential rain chances from Monday through Monday night. Better
chances for rain could come Tuesday or Tuesday night as a
shortwave trough pushes across the region. For now, will keep some
low end pops in the forecast from Monday into Tuesday, and go
higher with rain chances by Tuesday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 710 PM EST WED JAN 30 2019
Surface high pressure is building into the region, bringing cold,
Arctic air down into the upper Plains and Ohio Valley. At the
same time, an upper level disturbance is bringing some light snow
showers into Kentucky from Missouri and southern Illinois. This is
expected to move across the southern portion of our area, but
only bring light accumulations overnight. Have accounted for this
mainly for the SME and LOZ TAFs, but did include JKL. Areas in the
north will not be affected and confidence is low if areas in the
northeast near SJS would be affected. Other than some possible
lowering of VIS in the heavier snow showers, VFR conditions are
expected throughout the TAF period. Winds will generally be light,
westerly winds will shift to be more southwesterly by tomorrow
afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CGAL
SHORT TERM...SHALLENBERGER
LONG TERM...HC/KAS
AVIATION...CGAL
Area Forecast Discussion
National Weather Service Louisville KY
831 PM EST Wed Jan 30 2019
.Forecast Update...
Issued at 830 PM EST Wed Jan 30 2019
A band of light snow associated with weak mid-level forcing is
working into the western CWA this evening. It appears flurries can
be expected as far north as I-64, though the better chance for light
accumulation is a bit further south. Areas south of a line from
Brandenburg to Madison have the best chance at seeing a dusting up
to a half inch of snow. The primary moderate snow band over
southeastern Missouri has been weakening, and this is in line with
HRRR forecasts. There is some dry air to overcome, though dewpoints
are higher (closer to 0) in the southwestern CWA. Due to the cold
temperatures and high ratios, roads could quickly become partially
snow-covered and slick from any light snow tonight.
&&
.Short Term...(This evening through Thursday)
Issued at 305 PM EST Wed Jan 30 2019
...Light Snow Accumulations Tonight In Southern/Central Kentucky...
Arctic air has settled over the region today, resulting in very cold
temperatures and wind chills. Still seeing wind chills in the -10 to
-15 values across northern Kentucky and southern Indiana where the
wind chill advisory remains in effect. With winds expected to die
down some this evening, still looks like we should be able to drop
the wind chill advisory for central/northern Kentucky by 22z, and
southern Indiana by 00z.
Clouds will increase late this afternoon ahead of a weak wave that
is forecast to impact parts of central/southern Kentucky. This
system looks to be very moisture starved, but considering the cold
temperatures in place, snow-liquid ratios will be quite high and it
won`t take much to put snow accumulations on the ground. Using a
blend of short range model guidance, thinking snow will start
tonight after 02z-03z near the BWG metro area, and push eastward
through the remainder of the night. Leaned toward the higher end of
model snowfall guidance, which puts accumulations in the dusting to
half inch range along and south of a line from Owensboro, KY to
Berea, KY. After coordinating with surrounding offices, have decided
to highlight the snow/travel threats with an SPS. While no advisory
is in effect right now, there is still the potential to see lightly
snow covered roads that would result in slick travel conditions for
parts of southern/central Kentucky. Use caution if you plan to
travel late tonight or early tomorrow morning in these areas.
Temperatures overnight will be a bit tricky. We may see some
mid/high level clouds stream into southern Indiana during parts of
the night, but thinking most of the overnight hours will be clear.
This should allow temperatures to drop to below zero values for a
time, especially since we have a snowpack in place. Surface high
pressure nudging in from the northwest will also help winds to drop
off toward dawn. Farther south into central/southern Kentucky,
clouds should keep temperatures from falling too much overnight.
Still expecting a very cold night there, with lows in the single
digits.
Clouds will continue to stick around tomorrow, and eventually
overtake southern Indiana by late morning. While low level profiles
look to be dry, it`s possible we could see some flurries or very
light snow showers during the day Thursday. Temperatures will be
"warmer" tomorrow, but still below climatological normals as highs
range from 20s to low 30s across southern Indiana and central
Kentucky.
.Long Term...(Thursday night through Wednesday)
Issued at 255 PM EST Wed Jan 30 2019
...Transition from cold to very mild weather during period...
Thursday night and Friday...
Thu night will be the last night of the brief very cold weather
across our region, as low-level warm advection/isentropic lift kicks
in. However, in this advection regime, enough saturation aloft
should develop to support some light precip late Thu night and Fri
within NW flow aloft. The concern is what the low-level thermal
profile will look like when precip starts. At times, models can
erode surface cold air too quickly, although surface winds will
switch around to southerly Thu night. All models are showing
moderating temperatures to at or above freezing in low-levels by Fri
morning. Although low temps are expected in the 20s in most areas
Thu night/Fri morning, these values will occur Thu evening, with
temps then slowly rising overnight.
The timing of sufficient air mass saturation and light precip
production will dictate what precip types actually occur. At this
time, the predominant precip type should be or become light rain,
but there could well be a period of light freezing rain or sleet
before changeover to liquid late Thu night/Fri morning, so will keep
on eye on this. Precip during the day Fri will be mainly light rain
with afternoon highs rising to the lower-mid 40s at many locations.
Saturday and Sunday...
The beginning of a pattern change aloft occurs with a switch to W
then SW flow aloft. Milder low-level air and higher heights aloft
will push into the Ohio Valley. Sat and Sun should be dry with highs
Sat afternoon reaching the 50s, and easily in the upper 50s and
lower 60s Sun afternoon.
Monday thru Wednesday...
Mild weather will continue with above normal temps most of the time.
An active SW flow aloft will bring at least a couple periods of rain
showers as well. Models generally agree that the first system on Mon
will cause scattered to numerous showers for at least the first half
of the day, with isolated showers later in the day. High temps will
depend on the amount of clouds and precip, but 60s are expected.
This would be roughly 20 degrees above normal...a far far cry from
temps today.
Another weather system follows quickly on the heels of the Monday
system in the SW flow aloft. This will bring additional rain showers
to our area late Tue into early Wed. Modest instability could
accompany this system, so a few thunderstorms are possible as well.
The weather will continue mild Tue with slightly cooler air Wed.
&&
.Aviation...(00Z TAF Issuance)
Updated at 640 PM EST Wed Jan 30 2019
BKN mid-level cloud deck quickly streaming in from the WNW this
evening. A band of light to moderate snow falling from these clouds
is expected to move across central and southern KY between 02-07z.
Despite dry low level air and a sfc high in the region, a narrow
band of snow may result in IFR vsbys at BWG between 02-06z. Lighter
snow on the northern fringe of the precip could impact SDF with MVFR
vsbys. Due to the cold temperatures and high snow ratios, a quick
dusting is possible at SDF. BWG could see a half inch of
accumulation. Ceilings are forecast to stay VFR, but any moderate
snow at BWG would likely produce MVFR ceilings.
NW winds around 5-7 kts will gradually diminish and become light and
variable by daybreak. Winds will then turn southerly by late
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...EBW
Short Term...DM
Long Term...TWF
Aviation...EBW
Area Forecast Discussion
National Weather Service Morristown TN
855 PM EST Wed Jan 30 2019
.DISCUSSION...
Another bitterly cold night forecast with temperatures already in
the teens and 20s with most locations forecast to drop down into
the single digits and teens. Overnight lows are on the warmer side
of forecast guidance with winds still remaining up and a deck of
clouds moving in from the west preventing ideal radiational
cooling conditions.
The area of snow back to the west in association with a fast
moving mid-level trough is the other point of interest for the
update tonight. Radar imagery and surface observations indicate a
broad area of light snow across Missouri, southern Illinois and
western Kentucky. Most models indicate that this area of snow
should have dissipated by now but the HRRR seems to have the best
handle on the situation. The HRRR indicate that this area of light
snow will hold together into southwest Virginia and have increased
PoPs for the update. The system is rather progressive and the
chances for snow will only last from around 05-08z. The ground is
cold after the last couple of days and have mentioned a dusting up
to a couple of tenths of an inch of accumulation for southwest
Virginia.
Winds will continue to decrease overnight but wind chills will
still drop to 5 to 10 below zero across the higher elevations of
the east Tennessee mountains and the higher elevations of
southwest Virginia where a wind chill advisory continues through
10 AM Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 19 44 30 53 / 0 0 0 10
Knoxville McGhee Tyson Airport, TN 14 38 27 49 / 0 0 10 20
Oak Ridge, TN 14 39 28 47 / 10 0 10 20
Tri Cities Airport, TN 8 33 23 46 / 10 0 10 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...Wind Chill Advisory until 10 AM EST Thursday for Blount Smoky
Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast
Monroe-Unicoi.
VA...Wind Chill Advisory until 10 AM EST Thursday for Russell-
Washington-Wise.
&&
$$
MA
Area Forecast Discussion
National Weather Service Norman OK
811 PM CST Wed Jan 30 2019
.UPDATE...
Updated to lower forecast low temperatures for tonight.
&&
.DISCUSSION...
Temperatures have decreased quickly across the area this evening,
especially in northern Oklahoma. Mesonet sites are down to 17 at
Newkirk (Kay County) and 20 at May Ranch (northern Woods County).
Clear skies and relatively light winds should allow additional
cooling this evening and overnight. Winds across the northeastern
portion of the forecast area are from east or east-northeast with
some cold air advection continuing. Farther southwest, the winds
have come around to southeasterly/southerly which may prevent the
temperatures from falling as much. Have generally lowered the
forecast mins across the board this evening, but especially in the
north where temperatures will continue to fall more significantly.
A blend of HRRR and RAP temperatures seemed reasonable overnight.
&&
.PREV DISCUSSION... /issued 537 PM CST Wed Jan 30 2019/
DISCUSSION...
The 00Z aviation discussion follows....
AVIATION...
The southwest edge of the arctic airmass currently over Oklahoma
will shift east tonight and tomorrow, allowing a return to
southerly winds near the surface. Increasing low-level moisture
will bring increasing clouds to most of north Texas and Oklahoma
early Thursday. These clouds will likely linger through the day
along and east of I-35. It appears that conditions will only
deteriorate further after 00Z tomorrow evening into Friday.
CmS
PREV DISCUSSION... /issued 431 PM CST Wed Jan 30 2019/
DISCUSSION...
The main story for this discussion will be the gradual warmup over
the next few days, a series of shortwave troughs that bring
precipitation chances across the forecast areas, followed by another
surge of a cold airmass into the forecast area next week.
Currently, winds are currently shifting to the southeast and south
across most of the forecast area. Temperatures in North Central
Oklahoma appear to be increasing out of the 20s and may reach into
the lower 30s for high temperatures today, and the more rapid exit
of the cold air has bumped up the forecasted temperatures for the
remainder of the week. Along with the warmer temperatures, the
southerly winds are also advecting higher amounts of moisture into
the forecast area. This moisture coupled with the calm wind and
clear skies produce a chance of fog overnight Thursday night into
Friday morning. Similar chances for fog exist Saturday morning and
Sunday morning, however there is a higher uncertainty due to
possibly increased wind speeds those nights that would limit fog
development.
A series of shortwave troughs will bring slight chances of
showers and rain to the area. The first of the shortwaves will
move through Friday night into Saturday, with chances of rain
across the entire forecast area and higher chances across central
and southeastern Oklahoma. The next shortwave will move through
Sunday, with precipitation chances constrained to eastern parts of
the forecast area due to limitation to available moisture.
On Tuesday into Wednesday, a cyclone exiting Colorado into Kansas
will begin to intensify. This cyclogenesis will result in a cold
front that will move through Wednesday, which shift the winds to be
strong and out of the northwest and bring cold temperatures yet
again into the area. Currently, precipitation chances are kept
fairly low with the previously mentioned lack of available moisture
in the area, however this will be watched closely as this complex
moves closer.
Zwink
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 28 52 41 58 / 0 10 10 20
Hobart OK 29 58 37 61 / 0 0 10 10
Wichita Falls TX 35 60 45 64 / 0 0 10 10
Gage OK 23 56 27 57 / 0 0 0 10
Ponca City OK 17 49 36 54 / 0 10 10 20
Durant OK 33 50 44 59 / 0 10 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$