Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/21
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
710 PM CST Sat Nov 13 2021
.UPDATE...
Issued at 654 PM CST Sat Nov 13 2021
Find an updated aviation discussion at the bottom of this AFD.
Considering that the observed history of High Wind Warning-level
winds had been in-line with or exceeding RAP forecast half km
winds (due to stout pressure rises and CAA on the backside of the
clipper), and the latest RAP forecast continued marching this
level of wind across the rest of the forecast area through the
evening despite the sunset, we opted to upgrade all of the Wind
Advisory to High Wind Warning through 05z. Precipitation-wise,
most returns are near the low center, just clipping our far
northeastern CWA. Have adjusted PoPs accordingly. Patchy blowing
snow is most possible this evening across portions of the Prairie
Coteau, though morning rain/freezing rain may have helped to
crust-over the snow layer.
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 340 PM CST Sat Nov 13 2021
Precipitation has ended, and roadways are either drying out or have
just turned wet as temperatures have quickly risen above freezing at
most locations. The stronger winds have also assisted in drying out
area roadways over portions of central SD.
The concern now shifts to strong northwest winds behind the exiting
clipper low. As of 2130Z, winds have shifted out of the northwest
from around Eureka through Chamberlain. The strongest wind we`ve had
reported so far is 74 mph at the Grand River RAWS fire weather
station in Corson County. Have gone ahead and expanded our wind
headlines through the entire forecast area. Was initially concerned
that our eastern counties would only get to Wind Advisory levels for
an hour or two, but given the strong winds already being realized
over the central Dakotas, it seems reasonable to err on the side of
caution. May need to elevate our current headline another level over
the Sisseton Hills, but will wait to see if this is necessary.
Continue to put high end-or near high end CAM and other solutions
into our ongoing forecast for winds. 850mb winds across the cwa top
out between 40 and 70kts, lightest over our northern MN county.
Otherwise, temperatures will fall back into the 20s over the
northeastern third of SD and western MN, resulting in some re-
freezing of water on roadways which could cause some concern
especially on untreated roadways. Patchy blowing snow will remain
possible tonight across the Sisseton Hills. Temperatures will range
from around 30 degrees over west central MN to near 50 degrees over
our far southwestern counties Sunday afternoon as a quick surface
ridge sinks into eastern SD/western MN. Another round of light
precipitation will be possible Sunday night over north central to
eastern South Dakota, and west central Minnesota on warm air
advection. While precipitation will mainly stay in the form of rain
or snow, a light wintry mix will be possible mainly west of the
James River. Precipitation amounts still look very light at this
time.
.LONG TERM...(Monday through Saturday)
Issued at 340 PM CST Sat Nov 13 2021
At current time, the entire extended period looks to be dry. The
week starts off with upper level ridging and WAA at the surface both
Monday and Tuesday, which will result in above normal temperatures.
NBM looked reasonable for Monday, but did go with the NBM 75th
percentile for Tuesday as the NBM came in a bit too cool. A front
moves through on Wednesday, with cool high pressure settling in
during the middle part of the work week. As the high pushes off to
the east Thursday night, with see a fairly strong pressure gradient
develop, with breezy to windy conditions. The strong winds look to
be short lived through as an elongated low pressure system tracks
across the area on Friday. High pressure drops in behind the exiting
front and will be the dominant feature on Saturday.
High temperatures will range from around 40 in west central
Minnesota, to the upper 60s across south central South Dakota on
Monday, with highs in the mid 50s to the mid 60s on Tuesday. The
cooler air then moves in with highs in the 30s Wednesday, in the mid
30s to the mid 40s Thursday, and in the upper 30s to mid 40s Friday
and Saturday. Overnight lows will be in the mid 30s to mid 40s
Monday night, in the 20s Tuesday night, in the mid to upper teens
Wednesday night, and in the 20s Thursday night and Friday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 654 PM CST Sat Nov 13 2021
Terminals KABR,KATY,KPIR,KMBG
A strong surface low pressure area will bring very strong/high
northwest winds to the airports through tonight. Along with the
winds will come IFR/MVFR ceilings mainly at KABR/KATY and at ATY
perhaps even a little bit of light snow through late this evening.
PIR and MBG will have mainly low VFR/MVFR ceilings through late
tonight before skies clear Sunday morning.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning until 11 PM CST /10 PM MST/ this evening for
SDZ003>011-015>023-033>037-045-048-051.
MN...High Wind Warning until 11 PM CST this evening for MNZ039-046.
&&
$$
UPDATE...Lueck
SHORT TERM...KF
LONG TERM...Parkin
AVIATION...Dorn
Area Forecast Discussion
National Weather Service Burlington VT
1020 PM EST Sat Nov 13 2021
.SYNOPSIS...
Areal coverage of rain and snow continues to decrease across the
North Country tonight. Overnight there could be some slippery
travel as temperatures fall to near or slightly below freezing,
especially on any snow covered or untreated roads. Drivers are
encouraged to use caution. Additional precipitation chances are
expected throughout the upcoming week with seasonable
temperatures.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1020 PM EST Saturday...Made some minor adjustments to
account for current scenario. Continued highest probabilities
for precipitation over north central and northeast Vermont
through midnight, but precipitation amounts will be light as
dynamic forcing moves away from the area. Flow is also unblocked
to limit any additional enhanced precipitation. Eventually
there will be some lake effect showers moving into northern New
York as flow becomes a bit more southwest. Only other item of
note for tonight is lingering moisture or snow on roads could
result in some slick spots.
Previous Discussion...
A dynamically impressive system is well into the process of
developing as strong storms cross the Mid-Atlantic and
increasing low-level convergence and FGEN near the location of a
new, developing surface low is underway in southern New
England. Impressive upper divergence noted in the RAP analysis,
with high SEPV and omega values beginning to maximize now and
through the next 3-6 hours.
A swath of rain is lifting northwards as a negatively tilted upper
trough advects mid level moisture into our area. As the upper vort
max approaches, we should also see the deepening surface low shift
into New Hampshire about 5 PM. At times, precipitation will be
moderate to locally heavy in the eastern Adirondacks through
Vermont. We could see intervals of rain-snow mix as atmospheric
conditions cool. Falling snow levels are expected as the evening
progresses, with intervals of heavy, wet snow likely. It looks like
it could be one of those instances where the surface temperatures
are about 34 to 37, but with snow falling so quickly, we see some
accumulations anyway. Much of Vermont is likely to experience
between 0.33" and 0.67" of an inch of liquid. Across the valley
floors, little snow accumulation is expected. Across the
Adirondacks, amounts will mainly be between 0.1" and 1.0" of snow,
with 2-4" above 2000 foot elevation, and 4-6" at summits. For
Vermont, while most of the valleys will likely not see too much
snow, portions of central Vermont (near the surface low) and into
the Northeast Kingdom should see a few tenths to an inch. Over the
Northeast Kingdom, amounts should range between 1-4". Across higher
elevations of the Greens, anticipate 2-6", generally above 2000 feet
in elevation. Activity will wind down after 8 PM as the low tracks
east towards Maine with a transition to scattered lake effect
showers.
Intervals of heavy snow in the Adirondacks, mountain passes, and
eastern Vermont will cause sharp reductions in visibility.
Overnight, temperatures are expected to fall near to below freezing
across much of the forecast area. Any left over liquid that pools in
common problem spots could freeze over, resulting in black ice
formation. Slick roads will be likely, especially along mountain
passes and portions of the Northeast Kingdom. Drivers are urged to
use caution as we undergo our first more widespread snow event of
the year.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 348 PM EST Saturday...Temperatures will warm above freezing
Sunday morning as precipitation comes to an end. A few cold hollows
may remain near freezing until 9 to 10 AM. After this, the threat
for an areas of ice should diminish. Upper level shortwave will move
east of the region by Sunday afternoon as shortwave ridging very
briefly builds in aloft. Froude numbers show flow remaining
unblocked thru 18z so a few lingering showers are possible across
the high terrain, especially the northern peaks of the Green
Mountains as westerly flow remains in place. A dusting to a few
tenths of snow is possible for places like Jay Peak and locations
above 1500-2000ft in the NEK.
Our next trough is quickly on the heels of this one with scattered
rain/snow showers moving into the southern St Lawrence Valley Sunday
PM as flow backs to the SW. Areal coverage will increase after 00z
as the North Country is positioned favorably within the exit region
of a 140 kt upper level jet. Precipitation will begin as rain for
the valleys and snow for the higher terrain but will transition to
mostly snow for all locations outside the Champlain and St Lawrence
Valleys (a mix rain/snow is likely for the broader valleys) towards
06z. Expect snow accumulations to be light, with less than an inch
accumulation likely outside the highest terrain. Continued rain/snow
showers will persist through Tuesday as several shortwave impulses
pass overhead.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 348 PM EST Saturday...The pattern remains quite active through
the long term period as another long wave trough approaches the area
for the end of the week. A warm front will nose into our northern
zones Wednesday as an impulses rounds the periphery of high pressure
to our south. A period of freezing rain/mixed precip may be possible
as cold air remains in place for the northern St Lawrence Valley and
NEK of Vermont. This warm front will lift north Wednesday night
before the surface cold front approaches from the west Thursday
night. At this time, precipitation should be mainly rain for the
valleys with high elevation snow likely. Looking beyond the extend
period, the pattern remains active with several chances for
precipitation moving through.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...Generally looking at improving conditions
across the region this evening with a couple more hours of
MVFR/IFR RASN at KMPV/KRUT/KEFK through about 01-03Z. After 03Z
all sites will be VFR with periods of MVFR ceilings at
KSLK/KRUT/KEFK through the night. Winds will be westerly
overnight at 10kts or less, shifting to the WSW after 12Z.
Outlook...
Sunday Night: MVFR/IFR conditions possible. Likely SHRA, Chance
SHSN.
Monday: Mainly MVFR, with local IFR possible. Chance SHRA, Chance
SHSN.
Monday Night: MVFR/IFR conditions possible. Chance SHSN, Chance
SHRA.
Tuesday: Mainly VFR, with local MVFR possible. NO SIG WX.
Tuesday Night: VFR. Chance SHSN.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance SHSN.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Thursday: MVFR/IFR conditions possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Haynes
NEAR TERM...Evenson/Haynes
SHORT TERM...LaRocca
LONG TERM...LaRocca
AVIATION...Lahiff
Area Forecast Discussion
National Weather Service Dodge City KS
441 PM CST Sat Nov 13 2021
...Updated Aviation...
.SHORT TERM...(This evening through Sunday)
Issued at 358 PM CST Sat Nov 13 2021
The late afternoon water vapor loop and RAP analysis revealed a
perturbed northwest flow pattern across the western two-thirds of
the CONUS. A compact, yet fairly impressive jet streak within this
northwest flow pattern will continue to move out across the Northern
Plains and Upper Midwest region through the night tonight, and this
will push the next cold front down across Kansas. The front
overnight will be quick-moving with a small region of intense
pressure rises/isallobaric wind, and as such, there will be an hour
or two of fairly strong surface wind from the north overnight. We
tried to reflect this in the hourly wind grids, using quite a bit of
weight from NBM 90th percentile grids and the latest HRRR runs which
show some 20+ knot sustained surface and even higher gusts possible.
By daybreak, the strongest north winds will have abated, leaving the
rest of Sunday quite pleasant with very light wind as the surface
high will be centered across the Western Plains. The airmass behind
this storm system will not be all that cold with substantial
downslope modification. Abundant sunshine will help temperatures
reach 60F by late afternoon despite the very weak surface winds
which will limit deeper mixing. Given how progressive the overall
hemispheric pattern is right, the aforementioned surface high will
move quickly off to the east Sunday evening as a new leeside trough
forms across the Northern High Plains. Winds will become
southwesterly Sunday Night, which will prevent temperatures from
dropping much below the mid to upper 30s most locations. Off the
surface Sunday Night/early Monday morning, winds will be westerly,
aiding in a marked warm-up due to downslope off the Rockies. 12Z
Monday morning, temperatures at 850mb will be 14-17C, which will be
quite the rebound from 24hr prior 850mb temperatures of 4-8C.
.LONG TERM...(Sunday night through Saturday)
Issued at 358 PM CST Sat Nov 13 2021
As mentioned at the very end of the Short Term section, Monday
morning will start off very mild just off the surface due to classic
westerly downslope conditions. The classic west-northwesterly
downslope in the 850-700mb layer will yield 850mb temperatures well
into the upper teens degC and this will translate to mid to upper
70s at the surface just about everywhere across our forecast area of
west central, southwest, and south central Kansas.
It gets even better on Tuesday as the mid tropospheric flow
increases in strength across the Rockies, thus enhancing the
downslope across the High Plains. During the day Tuesday, we should
see 850mb temperatures in the 18-20C territory with a broad leeside
trough at the surface extending out across much of western Kansas.
This should keep the strongest MSLP gradient east of our forecast
area, so strongest south/southwest winds will be out across Oklahoma
and the southeastern half of Kansas. Official, we will be calling
for 74F for a high at DDC, 76F at GCK, and 81F at EHA. For what it
is worth, the latest NBM90th percentile grids show a high of 81F at
DDC on Tuesday and 86F at EHA! The record high for DDC on Tuesday is
87F, so it appears that record is quite safe.
The other shoe will drop Tuesday Night/Wednesday. The next
significant wave in the pattern will move quickly across the north-
central CONUS and will have quite a bit colder air behind it. Since
the storm system will remain an open trough and be centered north of
our area, precipitation chances will remain next to zero. We will
get the north wind, though, like we usually do with strong cold
advection in the low levels beginning late Tuesday Night and
continuing much of the day Wednesday with 850mb temperatures
crashing down to around 0C if not even a bit below zero degC by late
afternoon Wednesday. This will most likely result in daytime
temperatures not getting above mid to upper 40s. As mentioned
earlier, given how progressive the overall hemispheric pattern will
most likely be even mid-late next week, the cold airmass will be
fleeting as the airmass will recover quite quickly by the end of
next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 441 PM CST Sat Nov 13 2021
VFR will continue through this TAF cycle with varying amounts of
cirrus. A light west wind will prevail this evening. A strong but
dry cold front will race through the airports around 06z Sun, with
a 1-2 hour period of strong north winds. Nocturnal timing of the
frontal passage will reduce mixing, still gusts near 30 kts are
expected at all airports 06-08z Sun. North winds will weaken
rapidly through sunrise, and trend light and variable by 15z Sun
as a 1027 mb surface high settles over SW KS. After 21z Sun,
return flow and modest SW winds will return, with gusts near
20 kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 36 60 38 75 / 0 0 0 0
GCK 34 60 35 76 / 0 0 0 0
EHA 34 63 38 79 / 0 0 0 0
LBL 34 61 35 77 / 0 0 0 0
HYS 37 59 38 74 / 0 0 0 0
P28 40 61 37 73 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Turner
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
511 PM CST Sat Nov 13 2021
.AVIATION...
Some high cirrus remains across portions of south-central Texas
early this evening. Light S (I-35) to SE (DRT) winds tonight may
briefly decouple towards sunrise, and a strengthening low level jet
could lead to low level wind shear concerns between 09-14Z. Current
thinking is that wind speeds at 2k feet will remain just below
thresholds, with AUS and SAT most likely to deal with this as
stronger winds aloft will set up just to the north of these
terminals. Surface flow becomes southwesterly Sunday afternoon and
strengthens to 8-12 knots under mostly clear skies as VFR conditions
will remain in place through the period.
&&
.PREV DISCUSSION... /ISSUED 153 PM CST Sat Nov 13 2021/
SHORT TERM (Tonight through Sunday Night)...
Chamber of Commerce weather this afternoon across South Central
Texas, with just some thin cirrus in some areas, dry air, and
comfortable temperatures ongoing. A weak southerly flow will
continue to establish itself along and west of I-35 through the late
afternoon. A 30-40KT southwesterly low level jet is forecast to
develop tonight. Surface winds don`t fully de-couple, so this should
allow for warmer low temperatures tonight compared to last night,
but still cool.
Mixing of the higher momentum aloft downward to the surface will
take place late Sunday morning, resulting in a period of breezy
southwest winds developing through the Hill Country and I-35
corridor midday before weakening mid to late afternoon as a weak
cold front approaches from the north. Global models, and the
majority of the high resolution models, including now the 12Z HRRR
and 3KM NAM, stall the front weak front near or north of the SJT/EWX
CWA border Sunday evening and then wash it out. High temperatures
warmer on Sunday, forecast into the upper 70s to low 80s.
Dew points begin to slowly rise Sunday and Sunday night. Combined
with weaker winds Sunday night there could be some fog developing
near and east of the I-35 and I-37 corridor early Monday morning.
Some guidance suggests the possibility of dense fog across the
Coastal Plains.
LONG TERM (Monday through Saturday)...
Monday may start out with some patchy dense fog over the I-35
corridor and points east, as moisture return on the back of
southeasterly surface flow will aid in the development of decreased
visibilities. The afternoon looks stellar with highs in the upper 70s
over the Hill Country and the lower to middle 80s generally south and
west of I-10. The warm and dry trend looks to continue through
Wednesday as flow aloft remains westerly/northwesterly. On Wednesday,
height falls will start to spread over the Plains states as a large
trough carves out over the central CONUS. This will send a strong
cold front in our direction, with a chance for a few showers coming
through over the eastern half of the area on Thursday morning. Once
the front moves through, temperatures should be much cooler, with
highs in the 60s for most on Thursday. Beyond that, models diverge on
the next cold front expected to arrive next weekend. For now, will
hold off on mentioning PoPs greater than a slight chance.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 49 78 53 80 60 / 0 0 0 0 0
Austin Bergstrom Intl Airport 43 78 50 80 58 / 0 0 0 0 0
New Braunfels Muni Airport 46 78 53 81 58 / 0 0 0 0 0
Burnet Muni Airport 47 77 52 79 58 / 0 0 0 0 0
Del Rio Intl Airport 52 81 54 83 57 / 0 0 0 0 0
Georgetown Muni Airport 46 77 51 79 58 / 0 0 0 0 0
Hondo Muni Airport 46 80 51 81 56 / 0 0 0 0 0
San Marcos Muni Airport 46 78 51 80 57 / 0 0 0 0 0
La Grange - Fayette Regional 46 78 54 81 60 / 0 0 0 0 0
San Antonio Intl Airport 49 78 55 80 59 / 0 0 0 0 0
Stinson Muni Airport 48 81 56 82 60 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...KCW
Long-Term...Hampshire
Area Forecast Discussion
National Weather Service Grand Forks ND
934 PM CST Sat Nov 13 2021
.UPDATE...
Issued at 935 PM CST Sat Nov 13 2021
Extended the High Wind Warning across far southern Richland ND,
southern Wilkin MN, and Grant MN Counties until 11pm. High wind
corridor is still exiting the far southern portions of the RRV.
Else, visibilities have improved markedly across eastern ND and
along the RRV corridor in the wake of the departing Alberta
Clipper. Light snow and low clouds linger across northwest and
west central MN, but should continue to see improving visibilities
as the storm pushes out of the area through the late evening and
overnight hours.
UPDATE Issued at 744 PM CST Sat Nov 13 2021
Sent a quick forecast update to accompany a High Wind Warning for
far southeastern ND and portions of west-central MN. That high
speed wind corridor continues to track just south and west of a
surface low pressure system /Alberta Clipper/ which is just over
northwestern Otter Tail County attm, and Pelican Rapids MN rapids
and expected to continue its rapid southeasterly track out of the
FA over the next few hours. Lingering low clouds and areas of very
light snow will persist mainly over northwest MN throughout the
late evening hours.
&&
.SHORT TERM...(This afternoon through Sunday night)
Issued at 328 PM CST Sat Nov 13 2021
Short term impacts include winter travel impacts due to accumulating
snowfall through this evening across eastern ND and northwest MN.
Strong winds develop late this afternoon into the early evening
where less snow is expected and after main areas of snow have ended
in far southeast ND.
Mid level circulation associated with closed off short wave
trough/clipper is moving into northeast ND, and will be the focal
point for organizing mesoscale snow bands that is move northeast to
southeast over our CWA through the evening hours. Steep mid level
lapse rates/MUCAPE 100 J/KG near this center. RAP analysis currently
only shows transient pockets of frontogenesis, however radar is
showing the convective nature of the precip (cellular and banded). As
this pivots it may slow down and when this occurs bands may result
may support higher totals (6" or greater where bands linger). 12Z
HREF highlighted the potential for 1"/hr rates (30-40%) through our
central CWA late afternoon into the early evening matching these
ideas. Actual probs for 6" though are still lower (less than 5% in
WPC and NBM snow probs). This is likely due to the mesoscale
dominant/localized nature of the higher totals and progressive
nature of the parent mid level low. CAMs still highlight this
potential though with HREF showing max values around 6" possible.
Timing from HREF/NBM favors snow ending west to east this evening,
with only a few showers lingering in our far east towards the early
morning period. A Winter Weather Advisory remains in effect in all
but our far southwest where the track is less favorable.
Regarding precipitation type: There is a mid level dry pocket that
may be resulting in light freezing drizzle in the southern RRV, but
the window for this is over the next few hours. Max Tw aloft does
have a warm nose into our far south, but this low level moisture
isn`t as great and shouldn`t play a role in precip type where
organized returns will be tracking. So, a very light glaze can`t be
ruled out near the I-94 corridor, but impacts may be limited.
On the back side of this a strong LLJ is result in strong winds
across western ND and as the upper low swings east strong pressure
rises may support gusts around 45 mph in our far southwest and the
last few runs of the HRRR reflect this potential. Luckily this is
offset from where the more organized snow is expected to track, but
some overlap can`t be ruled out and localized blowing snow impacts
may develop. For now a Wind Advisory has been issued through 9 PM
for those locations.
.LONG TERM...(Monday through Saturday)
Issued at 328 PM CST Sat Nov 13 2021
The long term period starts off with northwest flow aloft and an
upper wave and associated clipper system moving across the area
Sunday night and out of the area Monday morning. South winds ahead
of the system will keep Sunday night lows in the teens and twenties,
with Monday highs in the mid to upper 40s. This will set up the
potential for some sort of wintry mix across the area Monday and
Tuesday, however QPF values are currently unimpressive. Given the
dry air aloft, freezing drizzle or snow is the most likely scenario.
By late Monday night, a short wave ridge moves across the northern
tier ahead of the next system progged for Tuesday night into
Wednesday. This system features a closed low moving across southern
Canada, with long wave troughing moving into the northern plains
Wednesday morning. Moisture fields are nearly average in terms of
climatological percentiles on both NAEFS and GEFS, however U-
component winds are around the 95th to 99th percentile for strong,
NW winds. The strong upper level flow combined with modest cold air
advection will bring a windy Wednesday with gusts potentially
nearing the 40 mph mark. Thus, at least minor impacts from windy
conditions and fresh snow are possible Wednesday morning, especially
along the international border. The cold push will bring single
digit lows to portions of northeastern ND Thursday morning.
As the upper low moves through Ontario and into northern Quebec
Thursday, ridging over the norther US and Canadian Rockies amplifies
and should bring quieter weather for the end of the week into early
next weekend. By Friday, afternoon highs rebound into the 30s to
near 40 across the south and remain in the 30s next Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 935 PM CST Sat Nov 13 2021
The center of an Alberta Clipper has pushed into central MN this
hour and will continue to track away from the forecast area
through the late evening hours. Expect widespread MVFR and patchy
IFR CIGS and VSBYS along the RRV corridor and eastward across
northwest and west central MN in wraparound clouds and snow bands
through 06z. After 06Z, expect improving visibility with areas of
MVFR CIGS continuing past 12z.
Over eastern ND, expect moderate northwesterly blayer winds and
areas of MVFR CIGS and VSBYS in very light snow. After 06z,
expect light northwesterly winds and patchy MVFR cigs.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...High Wind Warning until 11 PM CST this evening for NDZ053.
MN...Winter Weather Advisory until midnight CST tonight for MNZ005-
006-008-009-013>017-022>024-027-028-030>032.
High Wind Warning until 11 PM CST this evening for MNZ029-040.
$$
UPDATE...Gust
SHORT TERM...DJR
LONG TERM...Speicher
AVIATION...Gust
Area Forecast Discussion
National Weather Service Indianapolis IN
906 PM EST Sat Nov 13 2021
.Forecast Update...
Issued at 905 PM EST Sat Nov 13 2021
Surface analysis this evening shows deep low pressure in place over
western MN...with a frontal boundary ahead of the low stretching
across WI...and IA to MO. High pressure was in place over KY. GOES16
shows a extensive cloud shield in place over Indiana and IL...ahead
of the approaching cold front. GOES16 also clearly showing the
approaching Low with a classic cyclonic swirl. Radar shows SN over
NW IL and SW WI pushing SE.
Models overnight show the low to the north quickly diving SE within
the quick NW flow in place aloft. Warm air advection forcing is
expected to arrive overnight as HRRR suggests scattered SN
development after 09Z. Forecast soundings also trend toward
saturation overnight. Ptype should be snow as the entire column
appears to be below freezing. Thus have continued to include
increasing pops at most locations overnight as the best forcing
arrives. Road surfaces remain warm. Any minimal accumulations should
be contained to elevated and grassy surfaces. Given the expected
precip and cloud cover trended lows to the lower 30s.
&&
.Short Term...(This evening through Sunday night)
Issued at 158 PM EST Sat Nov 13 2021
An active weather pattern will be in place through the short term
period with rain, snow, and strong winds. Synoptically, a broad
upper level trough is exiting the area with a second stronger
trough moving into the area from the northwest. A surface low
associated with this trough is currently situated over North
Dakota and is expected to arrive in Indiana Sunday afternoon. A
few rounds of rain/snow will move through late tonight and again
during the daytime hours tomorrow. The first wave is associated
with a wave out ahead of the main low and jet streak and will move
through between 08Z and 12Z across the central and southern
counties. This wave of precipitation is expected to be a mix of
rain and snow. Model soundings show temperatures well below -5C
through much of the lower column with only a very shallow area
above freezing at the surface. Thus expect that snow will be the
predominant precip type with this initial band but with the
ground temperatures in the 35-40F range, much of this will melt by
sunrise or shortly after. Amounts with this initial band may be
upwards of a half inch to an inch but the total snow depth at any
time will be less.
During the daytime hours the main area of forcing is expected to
arrive across the area with increasing winds as the surface pressure
gradient rapidly climbs. Another broken line of rain/snow is then
expected during the morning to early afternoon hours as the surface
cold front arrives. This line may be more convective in nature with
the CAA causing fairly steep mid level lapse rates and creating a
non-zero CAPE environment. Confidence in the precipitation type for
this second round is fairly low at this time with the warmer surface
temperatures likely limiting the snow potential. Tds will be near
to below freezing so in periods of heavier precipitation there may
be a quick shift to snow which could allow for brief accumulations
of up to a half inch. Better chances for snow and accumulations
will be across the northern counties where surface temps will be
colder. As earlier mentioned, afternoon wind gusts will approach 45
mph at times with 850mb winds around 40kts and fairly efficient
mixing expected with the strong low level lapse rates.
After the frontal passage, strong northwesterly flow and CAA will
lead to periods of lake effect snow that may impact the far
northeastern counties but based on the expected near surface flow,
the better chances for any precipitation will be north of the
forecast area.
Temperatures tonight are expected to drop to near freezing before
gradually climbing tomorrow morning into the upper 30s. Temps
will then drop after the frontal passage with lows in the upper
20s tomorrow night.
Overall, expect that this will be the first accumulating snow for
much of the area with overnight snow tonight across the southern
counties and additional accumulations across the northern counties
tomorrow morning and early afternoon. The warm ground temperatures
will limit the snow depth at any time. The snow tomorrow could
overperform in spots with the convective nature of the snow. Total
snow will be less than an inch across the area.
&&
.Long Term...(Monday through Saturday)
Issued at 158 PM EST Sat Nov 13 2021
The return of warm air aloft will bring some forcing to central
Indiana on Monday. Isentropic lift along with some frontogenetical
forcing will occur across the area, but moisture will be mainly
confined in the mid and high levels of the atmosphere. Thus feel
that mentionable PoPs are not warranted, and will only include a
chance of sprinkles/flurries across parts of the area.
Dry and warmer conditions will rule Monday night into Tuesday as
upper flow becomes zonal across the area.
An upper trough will move into the area Wednesday into Thursday, and
this will bring a surface front through on Wednesday. These will
combine with adequate moisture to bring some rain to the area. The
latest GFS is slower than the other models, but for now will stick
with consensus and go with the highest PoPs on Wednesday afternoon
and evening.
High pressure will bring cooler and drier air for Thursday into most
of Friday. An approaching upper trough and cold front could bring
some precipitation Friday night and Saturday. Timing remains
uncertain that far out so have lower than usual confidence for PoPs
in these periods.
&&
.Aviation...(00Z TAF Issuance)
Issued at 556 PM EST Sat Nov 13 2021
IMPACTS:
- MVFR Cigs are expected for much of the TAF period,
- Brief periods of IFR ceilings are possible after 12Z.
- SCT RASN mix expected after 06Z before transitioning to RA after
13Z.
-Westerly winds gusting to 25kts at times through tomorrow.
Discussion: Cloudy skies with MVFR CIGS will continue for the rest
of the evening. An approaching short wave along with isentropic lift
will result in shower development overnight. HRRR shows sct
development across Central Indiana overnight and better overall
forcing after 12Z. Forecast soundings overnight show the column
below freezing until near 13Z. At that points temps within the lower
levels are suggested to be above freezing. Best forcing will exit
the area by 16Z-18Z...thus have ended precip mention at that point.
Cold air advection in the wake of the cold front will result in MVFR
stratocu Cigs for the rest of Sunday afternoon.
Wind will continue to be southwesterly at 12-15kts with gusts to
25kts at times. Gusts will briefly cease during the overnight hours
before ramping back up tomorrow.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Puma
Short Term...White
Long Term...50
Aviation...Puma
Area Forecast Discussion...UPDATED
National Weather Service Melbourne FL
959 PM EST Sat Nov 13 2021
.UPDATE...
Much welcomed drier air has advected into the region behind a weak
frontal system that moved through earlier today. Radar and Goes-16
satellite imagery depict the dry air over the area with water
vapor imagery showing even drier air upstream of east-central
Florida. High pressure building in behind the front can be thanked
for the dry air over much of the Deep South with the center of
high pressure currently located over Louisiana - building
poleward. With that said, the forecast is on track with a quiet
and dry night expected for the Space Coast. Temperatures will be
cooler behind the front, especially west-northwest of I-4 with
lows expected to drop into the upper 40s to low 50s. Elsewhere,
lows will drop into the mid 50s to low 60s.
&&
.PREV DISCUSSION... /issued 251 PM EST Sat Nov 13 2021/
Current-Evening...Showers ahead of cold front extend across the
Florida peninsula from Volusia to Sarasota counties. Currently no
lightning, and radar indicating tops are 12,000 feet or less, so no
strong convection going at the moment. The forecast for the frontal
passage the next few hours has become a battle of conflicting
elements. Dry air appears to be overrunning the convection with
dewpoints already in the mid to low-60s all the way to the Treasure
Coast, which will make storm development more difficult. However,
with fairly cold temperatures aloft, around -11C at 500 mb, a
thunderstorm can`t be ruled out. HRRR has been going back and forth
with the intensity of the line and how long it will hold together,
but generally depicts a few strong showers and a lightning storm or
two south of Highway 528 as the front moves across the southern
counties. Given the HRRR and the rain line holding together
reasonably, well have upped PoPs to 30% across most of the southern
counties and kept a slight chance of thunder between 23Z and 00Z.
Tonight-Sunday...(Modified Previous Discussion) Clearing skies and
no rain chances. West winds will veer north to northwest behind the
front, ushering in much cooler and drier air. Overnight lows will be
generally in the low to mid-50s, except mid-50s to around 60 further
south. High pressure broadly centered over the northern Gulf coast
will keep mostly clear and cool conditions in place Sunday with
highs remaining in the low to mid-70s across most of the the area.
Sunday Night-Tuesday...Cool high pressure traversing eastward over
the northern Gulf coast will keep high temperatures near to slightly
below normal through the beginning of the week. Highs in the low to
mid-70s on Monday, warming to the mid to upper 70s on Tuesday.
Northerly flow persisting behind the front through the day on Monday
will veer onshore into Tuesday. Winds around 10mph or so each
afternoon. Clear to mostly clear skies continuing, as very dry air
remains in place over the local area. PWATs through the period
generally 0.4-0.6", but are expected to increase slightly into
Tuesday to around 0.7-0.75" as flow becomes onshore. No
precipitation is expected.
Remainder of Week (modified previous)...The area flow pattern will
continue onshore through the end of the week, as high pressure
elongates over the wrn Atlc Basin north of the area. A notable
increase in moisture is advertised from the south during Wed
overnight and into Thu, as mentionable PoPs return to the area most
notably by Thu. The Treasure Coast and Lake Okeechobee should have
higher chcs of unfolding pcpn with the likelihood of rains and even
a storm or two, as a shortwave approaches from the central Gulf.
Temperatures warming slightly, reaching the upper 70s to low 80s
each afternoon, with lows warming from the upper 50s to upper 60s
from north to south on Thursday morning to the low to upper 60s by
Saturday morning.
&&
.AVIATION...
Increasing cloud cover through this afternoon/early evening as a
cold front works through central FL, but ceilings should remain
generally VFR outside of any precipitation. Ahead of this front,
short TEMPOs may be needed for brief reductions in visibility and
ceilings as a line of scattered showers moves quickly toward the
east through early this evening. Cloud cover will then quickly
decrease this evening and tonight from north to south as drier air
moves in behind the front with VFR conditions prevailing through the
end of the TAF period.
&&
.MARINE...
Rest of Today-Sunday...Showers possible through Volusia/Brevard
nearshore and offshore waters, and showers with a thunderstorm
possible across the Treasure Coast nearshore and offshore waters
this evening as a cold front passes over the waters. Westerly
winds 5-10 knots ahead of the front will veer northwesterly around
10 knots by Sunday. Seas 2-4 feet.
Sunday Night-Thursday...High pressure along the northern Gulf Coast
will travel eastward through early next week, stretching into the
western Atlantic by midweek. Locally, dry conditions continuing
through at least Tuesday, with isolated shower chances returning to
the waters off of the Treasure Coast on Wednesday. However, more
notable increase in PoPs is not expected to occur until Thursday.
Northerly winds around 15kts Sunday night into Monday will veer
onshore and ease slightly Tuesday through late week. Winds generally
around 10-15kts through the rest of the week. Seas 3-5ft, with up to
6ft in the Gulf Stream Monday evening into the overnight hours.
&&
.HYDROLOGY...
The Saint Johns River at Astor will continue a very slow decline
in the river level, but the river is forecast to remain above Minor
flood stage through early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 77 52 70 49 / 30 10 0 10
MCO 81 55 73 51 / 30 10 0 10
MLB 81 57 74 52 / 30 10 0 10
VRB 81 60 76 55 / 30 10 0 10
LEE 77 51 70 49 / 30 10 0 10
SFB 79 53 72 49 / 30 10 0 10
ORL 79 56 71 51 / 30 10 0 10
FPR 82 59 75 52 / 30 10 0 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Fehling/Cristaldi/Negron
Area Forecast Discussion
National Weather Service Marquette MI
745 PM EST Sat Nov 13 2021
.SHORT TERM...(This evening through Sunday)
Issued at 256 PM EST SAT NOV 13 2021
Lake-effect snowfall is slowly dwindling across Upper MI this
afternoon as weak ridging moves into the area ahead of an
approaching shortwave. While the lake-effect snow is expected to
weaken in intensity and coverage, don`t think that it will go away
entirely this afternoon and early this evening. Therefore, keeping
slight pops in fcst for the northwest wind lake effect belts this
afternoon and early this evening. Some rain may sneak in at spots in
the south central, east, and near the lakeshores this afternoon and
evening, but otherwise only snowfall is expected. For snowfall
amounts, expecting only a couple of inches across the northwest wind
lake-effect belts at most this afternoon, as temps across most of
the area have already gotten above freezing today. Still, could see
some slushy roads late this afternoon and into this evening,
especially near the Lake Superior shoreline where the snowfall
should continue. As for high temps today, given the lake-effect
cloud cover, not much above the 30s is expected for today, save that
some observations in the south central near Lake MI have reported
temps at or above 40F earlier this afternoon.
The shortwave low in the Northern Plains this afternoon is expected
to reach WI later tonight. This shortwave low is expected to bring
at the very least light snowfall across the CWA. This low should
also reinvigorate the lake-effect `machine` again in the north wind
lake-effect belts tonight, starting in the west. Could see some
advisory level snowfall amounts across the far west late tonight
into early Sunday morning, especially in the higher elevations like
the Porkies, as the shortwave forcing is enhanced by Lake Superior.
As we get further east and later in the night, expect lake
enhancement to lessen; instead, we should start seeing more pure
lake-effect snow showers in the north wind lake-effect belts.
Therefore, we could see some slick roads by tomorrow morning across
the area, in particular in the far west and higher elevations.
Expect lake-effect snowfall to continue Sunday in the north wind
lake-effect belts, shifting to the northwest wind lake-effect belts
late in the afternoon. Some locally heavy snowfall looks to be
possible in the north central Sunday, as a dominant band looks to
possibly set up near the Michigamme Highlands and move east as
the shortwave progs to Lower MI. 3-6 inches of snow look possible
in Marquette to Alger Counties Sunday, with higher amounts
possible, particularly in the higher elevations and in any place
the dominant band decides to `park` over (if it does so).
Therefore, expect slick roads and reduced visibilities if
traveling tomorrow, especially if you travel through the dominant
band. As for high temps Sunday, should see the entire UP in the
30s; some spots, like the Michigamme Highlands, could possibly not
even get above freezing Sunday. Also, areas within snowbands
(especially the dominant band) may have trouble getting above
freezing.
.LONG TERM...(Sunday night through Saturday)
Issued at 319 PM EST SAT NOV 13 2021
A broad upper-level ridge/trough pattern across North America will
continue into the long-term period leading to fast flow and
significant pattern swings. It will be an active week next week with
lake effect snow, a warm up, a strong cold front, and more lake
effect snow to end the week.
But the first order of business will be another round of lake effect
snow that will be continuing from Sunday through Sunday night and
into Monday morning. 850 mb temps will remain around -8 C Sunday
night so there will continue to be sufficient lake-based instability
with sfc-850 delta T`s around 17 C. As a "Manitoba Mauler" dives
southeastward through the Upper Great Lakes, another more subtle mid-
level short wave embedded within the large scale trough overhead
will drop southeastward across the eastern half of Lake Superior
Sunday night. This wave will bring a reinforcing shot of deeper
moisture and briefly back the mid-level wind to almost due
northerly. This means lake effect snow showers in the N to NW wind
LES belts, with particular focus on a potential dominant band pre-
conditioned by Lake Nipigon. Models have shown the Lake Nipigon
signal for several days and continue to do so today. However, there
is still some question as to where that dominant band sets up. The
general consensus among the models is for it to move onshore into
western Alger County, although some CAMs show it drifting as far
west as Marquette, which, while not likely, is at least plausible
given the slight backing of the wind in the 800-600 mb layer. On the
other hand, this slight backing aloft may provide just enough shear
to prevent the band from becoming stationary for too long, and thus
keep amounts in check. However if we do end up with a stationary
dominant LES band pre-conditioned by Lake Nipigon, there could end
up being locally significant snow totals. Have relied on the wetter
guidance (the RDPS, RAP, and HRRR mostly) and used a fairly
conservative SLR of around 12:1, to get additional snow amounts
after 00z Monday of 1-3" in Marquette and 3-6" in Alger, less along
the immediate lakeshore east of Shot Point where onshore flow will
keep temps at or just above freezing and cause some surface melting.
On Monday the trough will pull away to the east and with height
rises occurring, the column will dry out and winds will veer around
to westerly, leading to diminishing lake effect snow bands drifting
east in a typical fashion. With temps rising into the mid 30s for
highs, snow will struggle to stick during the daylight hours,
meaning that additional accumulation after sunrise Monday will be
minimal.
A quick warm-up begins Tuesday as a strong short wave digs into the
Canadian Rockies and drives amplification of an upper-level ridge
that will be spreading east across the Upper Great Lakes. There may
be some light rain Tuesday afternoon and night as the warm front
pushes through, but models generally show most of the forcing
remaining north of the U.P. and ensembles show only a minimal precip
signal. Tuesday night the U.P. will be in the warm sector of a
strong cyclone occluding over the Canadian Prairies leading to a
mild and breezy night with a non-diurnal temp curve. That system`s
cold front will then sweep across the area on Wednesday and winter
returns behind it. GEFS and EPS members are tightly clustered in
bringing 850 mb temps right back down to around -10 C Thursday, with
the GEFS running about 2 C cooler than the EPS on average. It
remains to be seen how much Lake Superior`s surface waters will cool
with upwelling from stronger winds Wednesday and Thursday, but in
all likelihood these fresh shot of cold air will be cold enough to
generate another round of lake effect snow on Thursday, primarily in
the W and WNW wind snow belts. This cold air aloft along with cloud
cover for much of the area will keep temps in the low to mid 30s for
highs. Lake effect snow should diminish Friday as surface ridging
moves in.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 713 PM EST SAT NOV 13 2021
VFR conditions this evening will give way to MVFR to IFR
conditions late tonight as an advancing low pressure trough brings
snow showers back into the area. This trough will also
reinvigorate n-nw wind lake effect snow on Sunday as colder air
moves in behind it. Expect MVFR to occasional IFR conditions in
LES to continue through Sunday. &&
.MARINE..
Active pattern continues for the next several days. Northerly winds
iwll increse to 20-30 kts late tonight and continue through Sunday,
strongest east half. Lake effect rain/snow showers will redevlop
Sunday, especially over the east half of the lake. There may be a
few stronger bands with reduced visibilities, especially Sunday
night from roughly Stannard Rock down to Munising. Winds across the
lake will subside below 20 kts by early Monday morning.
The next system arrives Tuesday evening with a brief period of
southerly gales likely north-central and east and winds 25-30 kts
elsewhere. A cold front will sweep across the lake on Wednesday with
winds veering to west behind it. A prolonged period of stronger
winds is likely Wednesday afternoon through late Thursday, with
gales likely during this time period. Some 40 kt winds are possible
central and east. The long period of stiff westerly winds will lead
to waves building to 12-15 ft Wednesday night and Thursday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...TAP
LONG TERM...RJC
AVIATION...Voss
MARINE...RJC
Area Forecast Discussion
National Weather Service Sacramento CA
222 PM PST Sat Nov 13 2021
.SYNOPSIS...
Dry and mild weather this weekend with areas of night and morning
valley fog. Cooling trend next week with mainly dry conditions
except light showers possible over far northern California Monday
night, and potentially again Thursday & Friday.
&&
.DISCUSSION...
Upper level ridging has brought stagnant conditions with light
winds. This coupled with moist ground and radiational cooling has
brought fog and low clouds which have dominated much of the
Valley and Delta areas weather overnight and today. They have kept
cool temperatures in those areas, generally in the 50s so far.
The notable exception is the northern Sacramento Valley, where
sunny skies have brought warm temperatures, reaching 79 in Redding
at 1 pm. The fog was quite dense this morning, down to 1/16 mile
at Sacramento International Airport. A Dense Fog Advisory was in
effect until noon, when the fog lifted into low stratus. These low
clouds have gradually been eroding from north to south allowing
for increasing sun and some warming. Some clouds may linger into
this evening, though, perhaps along the I-99 south of Sacramento.
This could potentially inhibit the return of fog tonight there.
North winds could again limit fog over the northern Sacramento
Valley overnight, though since they are a bit weaker some patchy
fog could make it a little farther north. HREF and HRRR strongly
suggest patchy fog will develop this evening, then become dense
overnight, though exactly when is a bit uncertain. Motorists
should be prepared for periods of reduced visibility tonight into
Sunday morning.
The upper ridge axis shifts inland over NorCal Sunday with the fog
lingering through the morning fog in the Central Valley and Delta.
Additional warming of 2 to 5 degrees is possible with highs in the
upper 60s to lower 70s forecast in the lower elevations, with the
warmest areas again over the northern Sacramento Valley.
The ridge begins to flatten Monday as a weak upstream Pacific
frontal system approaches. This is projected to to move across
northern portions of the area Monday night, with best chance of
some precipitation over the mountains of Shasta County.
Baroclinic zone modeled to weaken as it moves inland and overall
QPF looks light and limited to mainly Shasta County, with a slight
chance of rain extending into northern Tehama County. Rainfall
amounts should be quite light, around a couple hundredths of an
inch.
Upper ridging rebuilds inland Tuesday with locally gusty north to
east wind. Low level Cold Air Advection will continue a slow
downward trend in high temperatures into midweek.
&&
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Weak ridging on Wednesday is followed by more zonal flow
Wednesday night into Thursday. Ensemble guidance is still quite
split for late week with over 30 percent of members indicating
ridging across the west coast during this time. Deterministic runs
have trended towards a shortwave system moving across the area
that would lead to precipitation for portions of interior NorCal.
Went mostly with the NBM for low end PoPs during this time given
the uncertainty. Stay tuned. Temperatures look to be near average
from mid to late week. &&
.AVIATION...
Stratus continues over the northern San Joaquin Valley this
afternoon, dissipating after 23Z. Widespread LIFR conditions are
expected again tomorrow after 04Z in the Central Valley as fog
redevelops. Elsewhere, VFR conditions will prevail next 24 hours.
Surface wind gusts under 10 kts. &&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$