Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/02/22
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
558 PM CST Tue Feb 1 2022
.Discussion...
Issued at 327 PM CST TUE FEB 1 2022
Key Messages:
- Winter storm still expected to impact the area tonight through
Thursday.
This winter storm really looks like it can be broken down into two
distinct events that blend together. The first event really gets
going this evening through late Wednesday morning or early Wednesday
afternoon. The second, Wednesday evening into Thursday afternoon.
It`s this second round that is leading to a lot uncertainty with the
storm total snowfall due to a tight gradient on the northern side of
the precipitation area from no snow to heavy snow. When the gradient
is this tight, literally a county to county and half wide, any minor
movement in the system really affects snow amounts in that gradient
area.
For the first event, a well pronounced coupled jet structure
develops over the region. This induces strong upward motions and
strong isentropic ascent that is most notable on the 290K surface
but also noted at 285K and 295K before weakening higher up at
300K. In the lower levels, strong frontogenesis develops enhancing
the overall vertical motions. This area of frontogenesis really
shows up well in the 800MB to 750MB layer develops over the
northern half of the forecast area before sliding south through
the evening and overnight hours, eventually moving into southern
MO by tomorrow morning, helping wind down, but not completely end,
the first round of snowfall before the second round begins. The
strong forcing with the coupled jet, deep isentropic ascent, and
the strong frontogenesis will lead to sizable accumulations and
potentially most of the snowfall for the KC metro between the two
events.
Within this first round of precipitation, there will be a short window
of mixed precipitation, especially further south, as there remains
an elevated warm nose initially. This is mostly eroded by cold
advection aloft but may be aided by the increase in upward vertical
motions cooling the column as well. Regardless, there may be some
sleet and freezing rain, mainly across our southern zones as the area
transitions from rain to snow.
For the second round of precipitation, the main upper shortwave
trough will begin to move across the middle of the country. At the
surface, a strong high pressure area will be moving southward. There
is very dry air associated with this high pressure area that will be
advecting into the northern half to three quarters of the forecast
area. This dry air may be too much to overcome for the lift
associated with the wave and as a result, the northern extent of the
snow area may be farther south. There remains considerable
uncertainty though regarding this. Most 12Z guidance seemed to
indicate more of a southward trend in this second precip area as the
dry air looked to dominate over the forcing. But some of the latest
18Z guidance casts some doubts about that. The 18Z HRRR and the NAM
3km both bring snow back into the area late Wednesday afternoon and
evening. That said, it still is more likely that the heavier snow
with this second round will be across the southern fourth of the
forecast area, mainly south of I-70.
Bitterly cold air will settle into the region, particularly Friday
morning when lows fall to around 0F. From then on there will be a
warming trend into next week as temperatures may climb back closer
to normal for this time of year. That could be modified downward due
to lingering snow cover. Otherwise, the extended portion of the
forecast looks quiet for now.
&&
.Aviation...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 558 PM CST TUE FEB 1 2022
Precipitation is beginning to fall at most of the terminals. Rain
is expected to transition over to snow over the next couple of
hours. Snow is expected to overtake the region overnight and
continue through Wednesday. Periods of heavy snowfall may
temporarily reduce CIGs and VIS to IFR. Timing of IFR conditions
remains sporadic and uncertain. It is anticipated that dips to IFR
will correlate with the heaviest rates of snowfall which are
expected tomorrow morning. Northerly winds around 12-18 kts
prevail with gusts of 25-30 kts possible throughout the entire
forecast period.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Winter Storm Warning from 9 PM this evening to 6 PM CST Thursday
for KSZ057-060-103>105.
Winter Weather Advisory from 9 PM this evening to 6 PM CST
Thursday for KSZ025.
Winter Weather Advisory from 9 PM this evening to noon CST
Wednesday for KSZ102.
MO...Winter Storm Warning from 9 PM this evening to 6 PM CST Thursday
for MOZ017-021>025-028>033-037>040-043>046-053-054.
Winter Weather Advisory from 9 PM this evening to 6 PM CST
Thursday for MOZ008-013>016-020.
Winter Weather Advisory from 9 PM this evening to noon CST
Wednesday for MOZ004>007-011-012.
&&
$$
Discussion...CDB
Aviation...Pesel
Area Forecast Discussion
National Weather Service Wichita KS
808 PM CST Tue Feb 1 2022
...Winter Mesoscale Update...
.MESOSCALE DISCUSSION...
Issued at 802 PM CST Tue Feb 1 2022
As of 02z/8pm, the left exit region of the upper jet is moving into
the Southern Plains, providing a more diffluent flow aloft across
Kansas/Oklahoma. The increasing large-scale forcing is becoming more
evident on radar imagery, showing an expanding field of precip
across central/eastern KS. Additionally, low-level WAA is increasing
(per recent RAP analyses and radar imagery) across southern KS, with
continued CAA to the north, leading to a tightening baroclinic zone
and increasing low-mid level frontogenesis across the area. The
increasing large-scale, and mesoscale, lift plus the incoming plume
of subtropical moisture is aiding in a deepening layer of moisture,
and this process should continue in earnest through the night. RAP
soundings reveal steep lapse rates above the baroclinic zone and
this appears to be contributing to the more showery/convective look
to the precip on radar. However, with time, the layer above the
frontal zone is forecast to stabilize, favoring a more solid, and
steadier, band of stratiform precip developing from NW to SE through
the night. It`s in this band of precip that we should see some light
to moderate snowfall rates (0.25"-0.75"/hr) develop, with
accumulating snow becoming increasingly likely. Where
frontogenesis is strongest/most persistent, there could be a brief
period where snowfall rates approach 1"/hr. However, the
transient nature of the mesoscale lift should keep the threat of
those higher rates low.
Where precip is the heaviest at this hour, wet-bulb processes have
led to a quick drop in temps down into the low 30s. In fact, parts
of south-central KS are colder than north-central KS due to this
process. Given the quicker fall in SFC temps, the ptype has
transitioned over to freezing rain/sleet/snow a little quicker
than expected, and the forecast has been adjusted to reflect this
trend. Road temps are also falling, but lag about 3 degrees behind
the air temps. Based on this trend, it will probably take temps
falling into the upper 20s before road impacts begin to increase
more, which should occur between 9pm-12am across central/south-
central KS, and after midnight across SE KS. Despite the earlier
onset of wintry precip across south-central KS, we don`t currently
anticipate a significant change in ice or snow accums as a lot of
this early wintry precip will get lost to melting. Current
headlines will still start as is, even with the sooner change to
frozen/freezing precip, because the impact period will still hold
off until later this evening.
Martin
&&
.SHORT TERM...(This evening through Friday night)
Issued at 423 PM CST Tue Feb 1 2022
Highlights:
1) Rain/drizzle this evening transitioning to wintry mix then all
snow
2) Moderate snowfall tonight through Wednesday
3) Dropping temperatures
4) Dangerous wind chills Thursday and Friday mornings
Changes: Decreased temperatures Wednesday-Friday
Challenges:
1) Exact timing of transition to all snow
2) End time of snowfall
Headlines:
Winter Storm Warning from 9PM tonight to 6AM (SC)/12PM (SE) Thursday
Winter Weather Advisory from 9PM tonight to 6AM Thursday (NC)
A low pressure system is situated over the Plains. Moisture
advection continues to push north. There is a bit of lift to bring
drizzle and just recently reports of mixed precipitation. As the
system moves further east, this will increase the coverage through
the evening and overnight. A wintry mix is still anticipated this
evening into tonight; southeast Kansas will have the longest
duration of a wintry mix from roughly midnight into Wednesday
morning. The wintry mix could include freezing rain and sleet as
well as snow of course; potential ice accumulation around a tenth of
an inch is forecast in southeast Kansas. There is still some
question on the exact timing of the arrival of cold air or
respective cloud ice to transition the precip type; in southeast
Kansas, questionable changeover timing to all snow could in turn
impact any ice or even snow accumulation initially.
The best period of lift is from roughly 10PM tonight through mid
morning Wednesday. Coincidentally this timeframe aligns with the
transition to all snow as the cold air moves in. There could be some
banding with the snowfall due to frontogenesis meaning that locally
higher amounts are possible. A wet surface from any rain will
initially make it harder for the snow to stick. However, this time
period does coincide with the best lift as mentioned which means
moderate snowfall is possible. A second round of moderate snowfall
is expected primarily southeast of the Kansas Turnpike Wednesday
evening/night to add onto their totals. Light snow is expected
throughout the day on Wednesday, so there will not necessarily be an
elongated break between the rounds. The overall lift for this system
is not necessarily overly impressive across the area with the better
lift to the east and south. In this case, it will essentially be an
extended period of snow (tonight-Thursday) with a deep dendritic
snow growth zone to help bring amounts of roughly three to nine
inches. This forecast does align with the previous one in terms of
timing and amounts.
Winds are another factor that will create a problematic scenario
with sustained speeds around 20 mph with gusts to 30 mph. Therefore
this will blow the lighter/fluffy snow given the thermal profile.
Coincidentally visibility reductions would occur. Another factor is
blowing and drifting snow; this is expected especially on east/west
running roadways given the northeast to northerly winds.
As mentioned cold air will move in to further drop temperatures.
Highs on Wednesday and Thursday are only forecast to reach the upper
teens to lower 20s. There was a decrease with this forecast issuance
closer to the 25th percentile of the NBM given clouds and snow
cover. Overnight temperatures will drop down to the single digits
Thursday morning and Friday morning. A 1040mb high pressure
system will push cold air down from the north which will come over
the fresh snow resulting in a cold start to Friday with low
temperatures around 0 degrees. Even though light winds are
expected, wind chills are forecast to range from 5 to 15 below
zero both on Thursday and Friday. If you head out, make sure to
bundle up and don`t forget about your pets. A wind chill headline
may be needed for Friday morning, but Thursday morning`s wind
chills have been mentioned in the current headlines to keep
things simple.
.LONG TERM...(Saturday through Tuesday)
Issued at 423 PM CST Tue Feb 1 2022
Highlights:
1) Gradual warm up but hinges on snow cover
2) Dry
A gradual warm up is expected for the end of the week into the
weekend, but this does hinge on the snowpack which could keep
temperatures lower. Given the snowpack, there have been slight
modifications to the temperatures. The forecast continues to have
afternoon highs back above the freezing mark (32 degrees) on
Saturday. Models are showing a couple of short waves coming across
through the weekend, but they appear to be dry in nature.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 613 PM CST Tue Feb 1 2022
* Winter storm underway. Widespread aviation impacts through THU
As of 23z/5pm, precipitation is beginning to expand in coverage and
intensity across the area. Below is a breakdown of the expectations
across the area this evening/overnight.
NORTH-CENTRAL KS (KRSL/KSLN/KGBD) - Precipitation will mostly fall
as SN, but may begin as a brief period of PLSN. CIGs will be slower
to fall in this area, and, for now, are expected to hold at VFR for
most of the night. Total snow of 2-5" expected.
SOUTH-CENTRAL KS (KHUT/KICT) - Precipitation will start as RA and
PL, then transition to SN between 03-06z. SN will then be the
predominant precip type through the remainder of the night. The risk
of FZRA looks minimal, and will be short-lived if it occurs at all.
The main risk for a brief period of FZRA will be at KICT. FZRA is
not expected at KHUT. CIGs should hold steady in the MVFR range
through the night, but could dip close to IFR as the steadier SN
develops. Total snow of 4-7" expected.
SOUTHEAST KS (KCNU) - Precipitation will be mostly RA, moderate at
times, for most of the evening. By 06z, the precipitation will begin
to transition to a FZRAPL mix as surface temps fall below freezing.
By Wednesday morning, the precipitation will transition to mostly
SN. The lowest CIGs and VIS will occur as the SN begins, with mostly
MVFR conditions prior to that. IFR conditions will be possible late
tonight through Wednesday, but I kept the TAFs more conservative for
now as low-level dry air advecting into the area may tend to keep
CIGs from falling too much. Total ice accumulation of a light glaze
to around 0.10". Total snow of 4-8" expected.
EXTENDED PLANNING OUTLOOK: Wintry precipitation (mostly SN) will
continue to impact aviation through Thursday, with the greatest
impact expected across southeast Kansas.
Martin
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 18 20 7 18 / 90 100 80 10
Hutchinson 15 19 5 18 / 90 100 70 10
Newton 16 17 5 17 / 90 100 70 10
ElDorado 18 18 7 17 / 100 100 80 10
Winfield-KWLD 20 22 8 17 / 90 90 80 20
Russell 13 18 3 21 / 90 90 40 0
Great Bend 13 18 3 19 / 90 100 70 10
Salina 15 19 5 22 / 90 90 30 0
McPherson 15 17 4 18 / 90 90 50 10
Coffeyville 22 24 11 21 / 80 90 90 20
Chanute 19 21 10 20 / 90 100 90 10
Iola 19 20 10 19 / 90 100 90 10
Parsons-KPPF 21 22 10 20 / 90 90 90 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon CST Thursday for KSZ053-070>072-
095-096-099-100.
Winter Storm Warning until 6 AM CST Thursday for KSZ050>052-
067>069-082-083-091>094-098.
Winter Weather Advisory until 6 AM CST Thursday for KSZ032-033-
047>049.
&&
$$
MESOSCALE...RM
SHORT TERM...VJP
LONG TERM...VJP
AVIATION...RM
Area Forecast Discussion
National Weather Service Indianapolis IN
944 PM EST Tue Feb 1 2022
.Forecast Update...
Issued at 944 PM EST Tue Feb 1 2022
Made some minor tweaks to PoPs, otherwise, radar was showing bulk of
the rain was lifting northeast across the Wabash Valley. Still,
expect the rain to spread southeast through the night. Temperatures
were on track and still in the middle 40s over northern sections and
upper 40s and lower 50s elsewhere. The HRRR BUFKIT LAF sounding
supports a changeover to sleet or perhaps freezing rain after 4 AM
for northwestern sections and then a quick transition to all snow.
The transition zone should then get as far south as a Kokomo to
Crawfordsville line by 7 AM. Areas north of this line could see
upwards of an inch or slightly more of snow overnight along with
light icing. This will cause some travel difficulties for the
morning commute. Timing is handled well in web site and social media
graphics.
&&
.Short Term...(This evening through Friday)
Issued at 258 PM EST Tue Feb 1 2022
Highlights:
-- High confidence in a significant, high-impact winter storm
especially for areas near and north of Indianapolis, but not
excluding other portions of the area.
-- Uncertainties remain with amounts and timing of precipitation
type transition.
-- Precipitation type transition order: Rain, freezing rain,
sleet, and eventually snow. Quicker transition period north, and
slower transition south.
-- Greater snowfall accumulations in northern and portions of
central Indiana, and greater ice and sleet accumulations across
southern Indiana.
-- Snow amounts and water content could cause snow load issues,
with property damage possible (i.e., trees, power lines, and
some roofs).
-- Dangerous cold possible Saturday morning including possible
sub-zero temperatures.
Messaging Recommendations:
-- Focus should be on significant impacts to daily life including
difficult to nearly impossible travel, and not necessarily on
specific amounts of snow and ice as some uncertainty remains.
-- Magnitudes of impacts for portions of the area could rival or
exceed some of our noteworthy past events including 1-2 February
2011, 14 February 2007, and 23 December 2004.
-- For further historical perspective, in Indianapolis, 10 inches
or more of snow in a two day period is a top 25 event. 11.5" or
more is a top 10 event. 16.1" is the record two day snow amount.
Meteorological Analysis and Uncertainties:
Potential scenarios have narrowed as model spread has decreased at
this stage. There are a few areas of uncertainties for portions
of the forecast that we will highlight below, but in general this
is a fairly high-confidence forecast, albeit with inherent
uncertainties related to precipitation type transitions.
On the synoptic scale, water vapor channel imagery shows a well-
defined shortwave trough moving from Lake Superior northeastward
into Ontario with an increasingly active southern stream into the
Southwest part of the country. Advected Layer Precipitable Water
shows an anomalous surge of deep moisture up through the Mississippi
Valley with strengthening warm advection attached to aforementioned
Ontario shortwave trough. Radar echoes are already noted in eastern
Illinois into west-central Indiana and these will continue to expand
as warm/moist advection regime increases.
We will enter a prolonged period of anomalous moisture and ascent
tonight, although there were be two distinct periods of stronger
ascent and deeper saturation. (1) during the day Wednesday, followed
by a lull in the heavier precipitation rates across the south, and
(2) early Thursday morning through at least mid-afternoon with the
second shortwave trough. In between, ascent and moisture will
still be present for precipitation but veering/weakening flow with
departing wave in Canada will favor generally light anafrontal
precipitation, except across northwest near the southwest-
northeast midlevel baroclinic zone. This is where frontogenesis is
quite strong and rates may be quite intense (2+ inches/hour) with
mesoscale banding. Also, as heavier precipitation rates depart,
trailing light-moderate deformation band could bring additional
light snow with higher snow-liquid ratios Thursday evening/night,
particularly across southern portions of the area.
This event differs from a more classic mid-latitude system in that a
dry conveyor belt isn`t at play to end precipitation quickly, and an
intense/anomalous closed midlevel low with well-defined deformation
to its north. Instead, while there will be some periods of strong
ascent, duration is the key factor with this event. Several hours of
at least moderate to occasionally strong omega within the dendritic
growth zone is indicated in NWP starting early Wednesday and
continuing through late Thursday.
The trend has been for quicker cold air arrival than earlier model
runs, and we have adjusted timing of precipitation transition
accordingly. This gives us enough confidence to upgrade the Winter
Storm Watch to a Winter Storm Warning for our entire area (including
our southern Indiana counties). By around midnight Wednesday night
our entire area should be below freezing, and it is possible if
trends continue we may need to speed the arrival of sub-freezing
temperatures further.
Uncertainty in forecast details increase slightly into Thursday
given run-to-run model differences with timing/amplitude of the
second wave, now organizing near California. GEFS ensemble
spaghetti plots of 500-mb contours is clustered enough that we`re
confident in another period of deeper ascent/moisture that could
be fairly significant on Thursday.
For all locations, the progression of precipitation type will be
rain, to a brief period of freezing rain, to sleet to snow. This
transition will occur quicker in the north than the south as warm
nose is a little more pronounced in the south. Models show there may
even be a slight nudge of 850-mb 0C line (good proxy for warm nose
on the plan view) northward which could at least stall precipitation
transition. As of right now, although a transient period of freezing
rain may occur, it does appear that as this happens the cold layer
will become sufficiently deep for a transition to sleet. In fact,
sleet may be heavy enough and last long enough accumulate across the
southern portion of the area. One half inch or more of sleet
accumulation seems increasingly likely across portions of southern
Indiana.
Implications further north where broad warm nose cools to below
freezing will be for snow-liquid ratio to be sub-climatology
yielding heavy wet snow, with possible heavy riming. Thus, our
concern for snow loading. Across the northern portion of our area,
SLR should be closer to climatology and with 25+ mph winds, some
blowing and drifting of snow is possible.
With a colder trend and some potential for a southward shift in QPF,
we still feel confident in significant snowfall amounts of near or
above 12" in some portions of the area. What we lose in QPF, we`ll
gain in increased SLR if the trend continues. This justifies
fairly high snow amounts even down into the I-70 corridor, hence
the upward trend in the forecast.
A final note to our broadcast meteorologists. We always
appreciate your critical role in communicating the impacts and
threats during these higher impact events. Thanks for your
partnership and please never hesitate to reach out to us if we can
assist in any way.
&&
.Long Term...(Friday night through Tuesday)
Issued at 258 PM EST Tue Feb 1 2022
We will cover the post-event weather into the weekend and early next
week only briefly. The main impact appears to be the potential for
dangerously cold temperatures over snow pack, particularly Saturday
morning when a period of light/calm winds and excellent radiational
cooling exists. Sub-zero and locally 10 below or less may occur.
There is a weak signal for light precipitation sometime early next
week in some medium range deterministic and ensemble guidance, but
confidence is low and no mention at this time. Later forecast will
clarify this potential.
&&
.Aviation...(00Z TAF Issuance)
Issued at 617 PM EST Tue Feb 1 2022
IMPACTS:
-Rain will spread NW to SE and start up around issuance time
at KLAF and 04z-06z Wednesday KHUF and KIND and finally
after 09z at KBMG.
-MVFR and worse flying conditions by around 03z at KLAF and
by 11z at the other terminals.
-Winds will shift from 160-180 degrees to 360-020 degrees
after 06z after KLAF and KHUF and not until after 22z at KIND.
Wind speeds will be mostly less than 10 knots through 12z and
then increasing in speed and become gusty first at KLAF after
12z.
DISCUSSION:
An inverted low pressure system will draw copious amounts of
moisture across the terminals tonight and Wednesday which
will allow for solid precipitation starting tonight at KLAF
and spreading southeast. As the precip spreads southeast,
it will transition over to perhaps freezing rain and sleet
from KLAF southeastward before snow becomes predominate.
This will also bring deteriorating flying conditions to the
terminals.
Winds from the south will back to the north Wednesday except
perhaps at KBMG. Wind speeds will be generally less than 10
knots but increase after 12z Wednesday with with gusts to
20 plus knots except at KBMG.
Marginal non-convective low level wind shear is possible at
times late tonight and mainly at KBMG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 7 PM Wednesday to 1 AM EST Friday for
INZ053>057-060>065-067>072.
Winter Storm Warning from 7 AM Wednesday to 1 AM EST Friday for
INZ030-035>049-051-052.
Winter Storm Warning from 1 AM Wednesday to 1 AM EST Friday for
INZ021-028-029-031.
&&
$$
Update...MK
Short Term...BRB/White
Long Term...BRB
Aviation...MK
Area Forecast Discussion
National Weather Service Melbourne FL
941 PM EST Tue Feb 1 2022
.DISCUSSION...
Although most of east central FL has been under partly to mostly
cloudy skies late this afternoon and evening, no shower activity
has been detected by our local Doppler radars. The low level
clouds that could produce some minimal rainfall overnight, are
moving from east to west and reaching the coastal counties. The
HRRR continues to show light showers reaching the coast through
the night but these were kept in the forecast for the offshore
waters only. Winds will be light from the east. Temperatures after
increasing to the lower-mid 70s today, will drop the mid 50s for
urban interior and coastal counties and to the upper 40s for rural
interior.
&&
.AVIATION...
VFR conditions through the night and into Wed. Light winds tonight
will increase to 10-15 kt with brief gusts up to 20 kt by mid-
morning from the east then veer from the southeast in the
afternoon.
&&
.MARINE...
As the pressure gradient starts to strengthen tonight, winds will
increase to around 18 kt late tonight from the east then veer
from the southwest through the day. Therefore, operators of small
craft should exercise caution across all the waters except
nearshore Volusia. Seas 3-4 ft tonight, building to 4-5 ft
offshore on Wednesday.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Negron/Watson