Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/20/21
Area Forecast Discussion
National Weather Service Gaylord MI
1024 PM EST Sun Dec 19 2021
.UPDATE...
Issued at 1002 PM EST Sun Dec 19 2021
Two concerns will be the onset to the gusty winds, and the onset
of the precipitation. Have adjusted the winds as the gusts have
been on the low side. The gradient in the return flow will tighten
up eventually, but so far it hasn`t. So have lowered the winds in
N Lower for a time before they begin to increase a little later.
CAMs are on the side of the going forecast with light precipitation
getting going overnight. If anything, the ARW and Fv3 are too
agressive, starting the precipitation in C/E Upper almost now
(radar shows that it hasn`t (KMQT and KAPX). The RAP13 and HRRR
look closer with after 09z/Mon. We`ll see, the going forecast is
after 06z/Mon and lasting into Monday morning. Will keep that
timing and continue to watch.
&&
.NEAR TERM...(Through Tonight)
Issued at 258 PM EST Sun Dec 19 2021
...Mostly Cloudy and Brisk...
High Impact Weather Potential...Low.
Surface high pressure will slide off to our east through this
evening. Attention will then turn to a short wave racing out of
the northern Rockies toward the western Great Lakes. The surface
reflection of this wave will pass by to our north on Monday. As
the pressure gradient tightens up tonight south southwest winds
will increase making it feel rather brisk even though temperatures
hold nearly steady or even rise a bit overnight. There could be a
few snow showers across eastern upper late tonight. Can`t totally
rule out a touch of drizzle or freezing drizzle but will not
include that in the forecast as the probability of occurrence
appears rather low. No sensible weather is expected across
northern lower tonight...just thickening cloud cover. Lows this
evening in the mid 20s to around 30.
&&
.SHORT TERM...(Monday through Wednesday)
Issued at 258 PM EST Sun Dec 19 2021
High Impact Weather Potential: Accumulating snow Tuesday into
Tuesday night...
Pattern Synopsis/Forecast:
High pressure prevails over much of the Great Lakes this
morning...as subsidence takes hold of the region, thanks to the
upper level jet departing eastward, placing us firmly in the left
entrance region of the jet...with some 500mb ridging sliding into
the area...though a few light snow showers/flurries linger across
parts of the area. Upstream...already looking at increasing moisture
aloft ahead of the next shortwave in the flow...with a couple
niblets of energy tracking through Alberta and Saskatchewan this
morning, north of a 100+kt jet straddling the International Border.
This is resulting in a 1001mb surface low over southeastern
Saskatchewan...with a longitudinally-oriented warm front extending
south into the Plains...with a cold front following the thermal
gradient aloft, more or less along the International Border out
west...stretching back to a second, weaker surface low in
southwestern Alberta. Flow further upstream is a bit split...as a
cutoff low sits off the West Coast...with a jet max digging into the
back of it this morning...resulting in some Pacific-based moisture
entering the picture for the northwestern US.
Going forward into Monday...that system across the Canadian prairies
will be approaching the Great Lakes...scraping through Northern
Michigan through the day, with the surface low remaining to our
north...as a niblet of energy treks through the southern half of the
CONUS. As we get into Tuesday...a more noteworthy shortwave dives
into the region...bringing the next (and better) shot of synoptic
precipitation to Northern Michigan as the surface low tracks across
the area this time. Lake effect should follow as well, given some
cooling aloft behind the system Tuesday night into Wednesday.
Upstream...looks as though the cutoff low does not remain cut off
for long...as deterministic guidance seems a little more coherent
today in it becoming absorbed by the flow...as the upper level jet
departs eastward into the CONUS...and a second niblet of energy
rides over anomalous ridging in the central Pacific to dive into the
backside of this strong troughing.
Primary Forecast Concerns: Gusty winds and snow
Monday...accumulating snow Tuesday with lake effect potential to
follow into Wednesday...
Looks as though gales may linger a few hours into the short term on
northern Lake Michigan...but should diminish with time as the better
wind fields depart the region with the system. Meanwhile, the other
impact for Monday will be that clipper system moving through the
region. Will look for some low-level convergence coincident with
some boundary layer moisture across Northern Lower in the
morning...though instability doesn`t appear terribly impressive with
this...and it may be signals of some west/southwest flow lake
enhancement off northern Lake Michigan across the Tip of the Mitt.
Better forcing and instability will be to our west, closer to the SW-
NE oriented cold front itself...which will sag south through the
region through the day. Would therefore look for better chances of
precip, mainly across Eastern Upper initially (as well as the Tip of
the Mitt)...perhaps spreading south with time. Across northern Lower
ahead of the front...signals don`t look terribly impressive for
precipitation...as both forcing and moisture seem to wane through
the day...additionally noting some mid-level drying per guidance-
derived soundings. Though this could indicate a lack of cloud ice
for a shallow (very shallow) saturated layer in the low levels, will
look for flurries rather than drizzle, given low-level thermal
profiles that appear more mixed/unstable. Behind the front in the
afternoon into early overnight...as some cooler air aloft moves into
the region, and flow switching over to more west to northwest with
time...would look for some potential lake effect, particularly
across the Eastern UP...though it doesn`t look overly impressive at
this time...with inversion heights running around 5kft or so at
highest, with some saturation in the DGZ. Lake effect will slowly
shut off through the night as high pressure and subsidence take hold
of the region.
Quick on the heels of the first system will be the second system for
Tuesday into Tuesday night. Warm advection will commence as early as
Tuesday morning...as surface high pressure and ridging aloft shoot
on through...allowing for southerly flow ahead of the next system.
This system will track a little further south than Monday`s
system...potentially dragging itself right on through Northern
Michigan. The plus side, from an impact standpoint, is that this
should keep winds relatively minimized, which is good. The downside
would be better forcing and moisture, leading to better potential
for precipitation. Departing jet from Monday`s system...and incoming
jet associated with Tuesday`s system...may lead to a bit of jet
coupling, increasing potential for upward motion on the downstream
side of the approaching shortwave aloft...which would otherwise
typically be favored for surface cyclogenesis. This upward motion
should advect into the area towards midday/afternoon
Tuesday...collocated with some deeper moisture in advance of the
trough, allowing for top-down saturation through the day. (May have
to watch for some seeder-feeder action early in the day as well.)
Best/deepest moisture attm looks to remain particularly across
Eastern Upper and into northern parts of Northern Lower...perhaps
toward M-72-ish or so...though most areas should see at least a
little bit. Will not be entirely surprised if we end up with some
higher SLRs/better snowfall rates at times Tuesday...as there are
some signals, per model soundings, for a deep saturated layer in the
DGZ in some areas, along with some better upward motion...so that
will be something to additionally keep an eye on going forward.
Signals for some intense low-level convergence right along the N-S
oriented front early Tuesday evening (noted in yesterday afternoon`s
AFD) remain in today`s guidance...suggesting the potential for a
band of locally intense snowfall right along the cold front. If
timing changes in the next few runs...this could become an issue for
the evening commute Tuesday (and anyone out doing their last minute
Christmas shopping that evening).
As the system departs Tuesday night...will look for flow to veer to
northwesterly...and with sufficiently cold air aloft (-8C or colder
at 925mb, for instance)...will look for some decent lake effect
potential into Wednesday. Currently...signals indicate potential for
some better NW flow convergence bands setting up in the usual areas
late Tuesday night into Wednesday morning...so will have to watch
this as well...as inversion heights initially appear to be up closer
to 10kft or greater Tuesday evening. Lake effect should linger into
at least the early part of Wednesday. Will already be watching some
mid-level moisture return to the area by later Wednesday...ahead of
the next little niblet of energy moving into the region.
.LONG TERM...(Wednesday night through Sunday)
Issued at 258 PM EST Sun Dec 19 2021
High Impact Weather Potential: Moderate...watching potential system
for Christmas weekend...
Pattern Synopsis/Forecast:
Next niblet of energy for Wednesday night into Thursday doesn`t look
overly impressive attm...as it lacks amplitude and forcing (at least
across our area), even compared to Monday`s system. Attention will
quickly turn to whatever happens for late week into the weekend,
which will be much more impactful.
Guidance is still struggling to some extent with the handling of
what remains of that cutoff low off the West Coast...as it attempts
to absorb into the flow later this week. Even so...there are signals
for the flow to become more amplified for Christmas Eve and
Christmas Day...as that broad area of troughing moves eastward into
the western US...allowing for ridging to build over the eastern
CONUS/Great Lakes ahead of the next system. Though guidance
currently seems to be trending a little more coherent in the upper
level pattern for the end of the week...there is still a lot of
uncertainty in the thermal patterns aloft, as well as the
position/timing of the resultant surface system. Details should
become clearer in coming days...but will ultimately look for things
to become active, windy, and potentially messy for yet another of
the busiest travel periods of the year. Naturally.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 702 PM EST Sun Dec 19 2021
The next front to move into the Upper Great Lakes is just getting
into N Minnesota, with clouds streaming out in front of it into N
Lower and E Upper. Looking upstream the VFR category CIGs will
begin to drop into the MVFR category through the night, but will
be expecting occasional breaks in the clouds to interrupt a
constant cloud deck. Otherwise, the winds will increase tonight as
the system approaches the region.
&&
.MARINE...
Issued at 258 PM EST Sun Dec 19 2021
The forecast will remain as is with increasingly gusty south
southwest winds tonight leading to a short period of gales across
Lake Michigan and the Staits. Small craft advisories elsewhere.
Winds subside a bit Monday into Monday night as they swing around
to northwest with widespread small craft advisory conditions.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 4 PM EST Monday for LHZ346>349.
GALE WARNING until 11 AM EST Monday for LHZ345.
LM...GALE WARNING until 11 AM EST Monday for LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY until 4 PM EST Monday for LSZ321-322.
&&
$$
UPDATE...JL
NEAR TERM...AS
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...JL
MARINE...AS
Area Forecast Discussion
National Weather Service Binghamton NY
925 PM EST Sun Dec 19 2021
.SYNOPSIS...
Scattered flurries southeast of Lake Ontario and the Finger
Lakes, become just some lingering lake clouds tonight. Clearing
occurs elsewhere tonight, allowing temperatures to plummet into
mainly teens. Weak disturbances may cause light precipitation
Tuesday morning and again Wednesday for the New York Thruway
counties, during an otherwise fairly quiet weather pattern.
&&
.NEAR TERM /THROUGH MONDAY/...
915 PM Update...
The flurries did last longer than expected but they appear to be
quickly diminishing. The RAP showed support for these flurries
diminishing within the next couple of hours. So a slight chance
was continued over parts of the Finger Lakes and Southern Tier
Regions until 04z (11pm). Then dry conditions are expected for
the rest of the night. Some minor tweaks were also made to
hourly temps, winds, and sky cover based on the latest
observations.
515 PM Update...
There continues to be some lingering flurries across the lower
Finger Lakes Region and extend down into the Twin Tiers. It is
beginning to diminish on the eastern extent but there are still
a few bands that continue. PoPs were increased for the area
where flurries are falling and decreased to the north for the
next hour. There is some uncertainty on how long it will last
but a blend of the CMC Regional and previous forecast was used
to have the southern extent retreat northward over the next few
hours. PoPs were also capped at slight chance as coverage will
become more limited. Otherwise, the rest of the forecast was
doing well so only minor adjustments were made to the other
forecast elements for the next few hours.
210 PM Update...
It will be a fairly quiet and chilly near term period, with
lingering lake effect flurries giving way to high pressure
tonight, then another weak wave approaches late Monday night.
While very light lake effect streamers are still showing on
radar aligned north-northwest to south-southeast especially
downwind of the Finger Lakes, they are drying up some more both
from a subsidence inversion lowering past 850mb, and widening
dewpoint depressions down below. The cloud deck is still there
even though it is becoming very shallow, but actual snow at this
point will generally just be scattered flurries with very
little if any accumulation. This is pretty much evolving as
expected. Calendar day highs already occurred at midnight and
daytime readings are mainly 20s-lower 30s under cold air
advection.
Lake effect clouds will linger into tonight immediately downwind
of eastern Lake Ontario and the Finger Lakes, and then as winds
go variable shallow moisture may remain trapped under the
subsidence inversion of building high pressure. Outside of
that, however, scattering and clearing will occur. Good
radiational cooling will allow most locations to plummet into
the teens for lows, and indeed some single digits will probably
be found in northern Oneida County where a light coating of snow
will further encourage the drop.
High pressure will hang on for a good chunk of Monday, with
mostly sunny sky south and some high thin clouds filtering the
sun in the north. The little bit of cloud cover will be
associated with warm air advection as high pressure departs, and
a weak system approaches. Despite the cold dawn, temperatures
will manage 30s for most locations, though lower elevations
could touch 40 degrees.
The approaching system will end up only skimming the area. Low
pressure will track from Central Ontario into Quebec, with a
trailing shallow cold front dipping into our region late Monday
night. Some snow showers could result roughly along and north of
the New York Thruway towards dawn, though it will first have to
overcome low level dry air. Lows Monday night will be in the
mid 20s to lower 30s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
255 PM Update...
A shortwave trough and associated weak cold front will be moving
through the area early Tuesday. A few flurries or light snow
showers may graze areas near and north of the Thruway as the
front passes by, followed by a light band of lake effect snow
that will stay mainly across northern Oneida and far northern
Onondaga Counties. However, low larger scale moisture
availability and directional wind shear will limit snowfall
amounts to an inch or less.
Partly to mostly sunny skies will prevail across most of the
remainder of the area most of the day Tuesday, with temperatures
near to slightly below normal. Clouds will begin to increase
from the west Tuesday night ahead of another system passing
through southern Ontario and Quebec. This system will bring
another mostly dry cold front through the area with lake effect
on the backside. The lake effect snow will mainly favor far
northern Oneida County through Wednesday afternoon, though the
focus will try to shift south Wednesday night. Again, lack of
moisture will be a limiting factor, though low level flow will
be better aligned and perhaps strong enough at 850 mb to try and
push snow well inland, but again amounts will be very light.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
255 PM Update...
High pressure will build across the east coast Thursday into
Friday, with little to no chances for precip, and temperatures
near seasonal levels to slightly above normal. Friday night
(Christmas Eve), an area of low pressure associated with two
shortwave troughs will move from the Upper Plains states into
the western Great Lakes. A developing warm front will lift
across the region ahead of the first shortwave trough, with
precip extending as far east as western NY/PA by midnight.
Precip will expand eastward as the front lifts north, aided by a
strengthening jet streak to our southwest. Some initial cooler
and drier air may limit the development of precip initially, and
while it may start out with a mix of rain and snow, it looks
likely to change over to mostly rain as the warm front lifts
north Saturday (Christmas day). Much will depend on the start
time of precip Friday night, and the northward progression of
the warm front Saturday. A small number of ensemble members keep
the front further south, held in place as a coastal low develops
off NJ, but these are heavily in the minority. For example, out
of 30 GFS Ensemble members, only 4 members suggest snowfall of
greater than 2 inches at BGM, and 7 members at SYR (a more
climatologically more likely spot for a warm front to stall
out)...and this is just based on a crude snowfall estimation
scheme that doesn`t properly take into account mixing
potential. Bottom line is the holidays look unsettled. It looks
more wet than white, especially the further south you go, but
given this is still deep in the extended range, things can still
change. Confidence in precipitation is moderate, confidence in
precip type is still low.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Lake effect clouds holding on across central NY and even into ne
PA this evening. 850mb ridge axis will move across the area
before 06Z which will shift the wind direction to the west/sw
and become light as well, with drier air moving in. The cloud
cover should lift and mix out between 00-05Z with ITH and BGM
likely being the last to go VFR. Weather conditions remain quiet
through the next 24 hours with VFR flight conditions persisting
as well. Winds will shift to the south and gust 10 to 15 kt by
Monday afternoon with some high clouds thickening up later in
the day.
Outlook...
Monday night through Friday...Mainly VFR; though weak
disturbances late Monday night-early Tuesday and again on
Wednesday, could cause brief light precipitation and minor
restrictions primarily for KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MDP
NEAR TERM...BTL/MDP
SHORT TERM...MPH
LONG TERM...MPH
AVIATION...BJT/MDP
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
539 PM CST Sun Dec 19 2021
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Latest surface observations and KBRO doppler radar
show MVFR ceilings with light-moderate rain prevailing across
Deep South Texas. The 22z run of the HRRR has intermittent light-
moderate rainfall continuing through the night and into Monday
morning as a upper-level disturbance moves into western Texas this
evening, coupled with coastal troughing occurring at the surface.
MVFR ceilings and visibilities should hold strong, but periods of
IFR visibilities are possible with heavier rainfall. Ceilings are
expected to improve through Monday morning, with VFR prevailing
anticipated in the afternoon.
&&
.PREV DISCUSSION... /issued 250 PM CST Sun Dec 19 2021/
SHORT TERM (Tonight through Monday Night): Damp and chilly Sunday
afternoon in progress with the rain shield having filled in nicely
over the last several hours. Inherited temp and PoP forecasts were
spot on, as temps have ever so slightly dipped further during the
daytime, with values in the upper 40s to near 50F across all of Deep
South Texas and the RGV as of this writing. Stiff NW winds of 10-
20mph are yielding apparent (wind-chill) temps in the mid-40s.
A mid/upper-level low, current seen spinning in water-vapor imagery
moving into the Mexican state of Chihuahua, will continue eastward,
reaching West Texas this evening with the trough axis progged to
move overhead ~15Z tomorrow (Monday). This low, combined with the
cool dome of air left behind by yesterday evening`s frontal passage,
will be the main driver of our weather for the next 24 hours. The
approach of the upper low is expected to induce a sharpening of the
coastal trough tonight, tightening the pressure gradient and leading
to another bump in northerly wind speeds overnight, particularly
offshore and near the coast. (Eventually the surface low closes off
as it ejects away from us tomorrow morning.) The approach of the
upper low also increases dynamic forcing for lift, with the 12Z NAM
run showing a hint of a right-entrance region of a jet-streak
overhead this evening, leading to some pretty decent omega values
aloft. This should lead to some steadier periods of rain and/or
showers overnight, with a rumble or two of thunder from elevated
convection not out of the question. Highest QPF is expected prior
to midnight, with event totals nearing 1" for the mid/Lower RGV by
early Monday morning. Overnight low temperatures (again, little
change was made) still forecast to be in the low-mid 40s, with wind-
chill values bottoming out in the 35-40F range.
Precip chances should end pretty quickly Monday morning, from west-
to-east, as the aforementioned trough axis aloft passes. Should see
some clearing by mid-afternoon, as column mean RH values drop to 30-
35%. Nudged temps up a couple of degrees due to expectation of at
least some sunshine, which puts most of the lower Valley in the
lower 60s, with mid-60s more common in the Rio Grande Plains. Monday
night looks pretty favorable for radiational cooling, though winds
aren`t expected to become dead calm...still light from the N/NW.
Because of this, leaned a bit into the lower temp guidance (NBM 50th
percentiles, which skews a bit lower, vs. NBM deterministic). So
temps could fall to the mid-30s across the Brooks/Kenedy County
Ranches while remaining in the low-mid 40s along the I-2 corridor
from Brownsville to McAllen.
As mentioned in the previous update AFD, went ahead and issued a
Coastal Flood Statement, valid from 3 PM to 11 PM. While
astronomical tides are low, observed values at both Port Isabel and
Brazos Santiago gauges have been running about 1.0 foot above
predicted. P-ETSS guidance suggesting water levels could approach
1.4-1.5 ft. MHHW around high tide at 7:22 PM, but with little shore-
normal component to the wave energy, am hesitant to issue an
Advisory.
LONG TERM (Tuesday through Sunday): The winter solstice
officially begins Tuesday at 9:59 AM CST. However, old man winter
is ignoring that memo and is instead going to be cranking up the
heat through the holiday weekend. Cooler than normal conditions
are expected Tuesday afternoon as a surface low impacting Florida
and a weak high in northeastern Texas keeps us in a light
northeasterly flow at the surface. As both of these move east, our
wind veers out of the east Wednesday to southeast by Thursday. As
a result, temperatures make the climb to near 80 Wednesday and
lower to middle 80s across Deep South Texas by Thursday afternoon
and are expected to stick around through the holiday weekend.
Overnight temperatures warm from the lower to middle 40s Tuesday
night to the 60s Christmas night.
What about rain chances? Pretty much zero through the period
thanks to an H5 ridge overhead in some capacity. However, surface
moisture will slowly be increasing Christmas Day and Sunday,
which may allow the possibility for a line of streamer showers to
develop Saturday night into Sunday. Models don`t handle such
events well, but with a surface ridge over the Bahamas and
increasing moisture, it`s at least worth a mention and something
to keep an eye on.
MARINE (Now through Monday Night): Small Craft Advisory
conditions still verifying at Buoy 42020, as well as the mid-lower
portions of the Laguna Madre, so have left the current SCA
configuration alone. As the coastal trough sharpens this evening,
model guidance has been consistent in showing another bump in
northerly wind speeds, especially on the Laguna and 0-20nm Gulf
waters, this evening. Current SCA on the bay is scheduled to
expire at 6pm CST, but may need to be extended or perhaps re-
issued later this evening. SCA for the Gulf waters is out through
6 AM CST tomorrow, but will likely need to be extended, at least
for the outer waters beyond 20nm, as seas are forecast to remain
agitated through much of the day. Winds and seas relax to more
moderate conditions Monday night as the surface low moves away
toward the east.
Tuesday through Friday: Calmer, more favorable, marine
conditions are expected Tuesday through Wednesday night. However,
the pressure gradient tightens in response to a developing area
of low pressure over the Upper Midwest Thursday into Christmas
Eve. This will cause elevated winds and builds seas to SCEC
conditions, with borderline SCA possible, Thursday night into
Christmas Eve.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 56 45 61 42 / 80 90 50 0
BROWNSVILLE 52 47 63 44 / 70 90 30 0
HARLINGEN 52 45 61 41 / 70 90 20 0
MCALLEN 52 45 63 44 / 70 90 10 0
RIO GRANDE CITY 51 44 65 40 / 70 80 0 0
SOUTH PADRE ISLAND 60 50 61 52 / 80 90 50 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Monday afternoon for TXZ256-257-
351.
GM...Small Craft Advisory until 6 AM CST Monday for GMZ130-132-135.
Small Craft Advisory until 9 AM CST Monday for GMZ150-155-170-
175.
&&
$$
This product is also available on the web at:
https://weather.gov/rgv
Aviation...67-Mejia
Area Forecast Discussion
National Weather Service Wilmington NC
1002 PM EST Sun Dec 19 2021
.SYNOPSIS...
A cold front will continue pushing offshore through this
evening, bringing drier and much cooler conditions through Mon
as high pressure rebuilds across the area. Coastal low pressure
system will renew rain chances across the area late Mon Night
thru early Wed. Drier and more seasonable weather later Wed into
Thu will be followed by a warming trend as we move into and
through the Christmas Holiday weekend.
&&
.UPDATE...
Marine...Upped the seas by 1 to as much as 3 ft for mainly the
period extending from this evening thru daytime Mon morning.
This based on latest nearshore and just offshore buoy trends, 2
examples...41013 having reached 10 ft and 41108 hovering at 5
to 6 ft. Held onto the few 35 kt wind gusts thru the evening hrs
with around 30 kt gusts thereafter.
Land...Based on latest CAA and the tightened sfc pg trends after
the CFP and what the latest HRRR and 18Z model runs
showed. Have indicated the main bulk of the clouds pushing off
the coast during the pre-dawn Mon hrs followed by thin-opaque
cirrus and possibly daytime stratocu, mainly due to the
strength of the NVA after the passage of the positively tilted
mid-level trof prior to daybreak Mon. Latest KLTX radar echoes
not quite reaching the ground or if so not registering across
local sfc obs attm. Removed pcpn from over land areas but kept
isolated/low chance threat across the local waters thru the
evening. Min temps tonight to occur at or up to 1.5 hrs after
daybreak Mon, the time when CAA peaks the layer between sfc and
925mb.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
A cold front will move east of the area tonight, taking the
rain with it and clearing the skies. After a mainly sunny day
Monday, clouds will increase Monday night with a small chance of
rain late over southern areas as another system approaches from
the Gulf Coast States. Mins tonight will fall to the low to mid
30s with highs Monday in the upper 40s to lower 50s. Mins
Monday night will fall to the mid to upper 30s.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Still expecting a dreary day Tuesday with increasing clouds and
a chilly rain developing...as a robust mid level short wave
tracks east along the northern Gulf Coast states and its
associated surface low emerging just off the SE Coast by
evening. Expect rain chances to increase from south to north
through the day as this occurs, with the highest chances over
our SC counties and also near the coast through Tuesday night.
Still some differences in the 12z model suite with this, but the
discrepancies aren`t quite as bad as previous runs so feel
better advertising a period of 60-80 POPs area wide. Ensemble
support for the highest QPF continues to be near the coast where
we are now showing over an inch storm total, with lower amounts
especially inland of an Olanta to Elizabethtown line. Did
undercut most of the guidance with max temps a bit with this
pattern, showing a range of upper 40s far inland to low/mid 50s
near the coast that will be influenced by ocean SSTs in the
upper 50s. NE trending N/NNW winds will be breezy at times esp.
near the coast, but with the low now expected to be a bit
further offshore, do not expect wind advisory criteria to be
met. Some lingering light rain near the coast esp. Wednesday
morning should clear out through the afternoon as much drier
mean layer RH air moves in. Highs mid-upper 50s for Wednesday.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Weak sfc high pressure will build into the area Thursday, with
large scale mid/upper ridging also moving overhead by Christmas
Eve Friday. This sets the stage for dry weather, with low to
mid 50s for highs Thursday warming into low to mid 60s Friday as
the sfc high begins to move offshore bringing a return of SW
winds. Will likely see a couple decent radiational cooling
nights with this pattern so may need to bring temps down
slightly for Thu-Sat mornings. At this point looks like we`ll
see some upper 20s in cool spots Wed/Thu night with low-mid 30s
elsewhere (upper 30s immediate coast). Showing a dry/warm
Christmas weekend with sfc high pres to our south and upper flow
trending zonal. Some signs in the guidance for a weak front
Sunday but with limited moisture, so kept POPs out for now. The
big news will be the warmth for the weekend though with mid-
upper 60s for most an even potential for low 70s on Christmas
Day.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Post FROPA MVFR ceilings, with patchy drizzle possible, should
last until late this evening or up to a few hours after
midnight at best especially across the coastal terminals. Vast
improvements to ceilings late in the pre-dawn Mon hrs with
mainly thin to opaque cirrus affecting the terminals for the
remainder of the 24 hr period. Gusty NNE-NE winds to dominate
this evening (20-25 kt gusts) as CAA and a tightened sfc pg
combine. Could be a brief reprieve to the gustiness during the
pre-dawn Mon hrs but expect NNE-NE winds to continue, just not
as gusty as Sun evening. Looking at generally 14 to 19 gusts
during daylight Mon, hiest at the coastal terminals.
Extended Outlook...VFR Mon evening. Coastal low pressure system
to affect the region late Mon night thru early Wed with possible
MVFR/IFR conditions. VFR to follow late Wed thru Fri.
&&
.MARINE...
Through Monday night: Expect N winds of 25 to 30 KT late this
afternoon to gradually diminish to 15 to 20 KT by late Monday
and continue Monday night. Seas of 3 to 4 FT will build to 4 to
6 FT tonight and continue into Monday with 7 footers possible at
20 NM. Seas will subside to 3 to 5 FT for Monday night.
Tuesday through Friday: Deteriorating marine conditions again
for Tuesday and Tuesday night as low pressure begins to
approach the area from the south. Seeing some better agreement
in the models that the low will remain just offshore of the
marine area, but potentially have multiple centers which may
allow for more than one period of surging NE trending N then NNW
winds late Tue through Wed. Potential for SCA conditions both
Tue and Wed. Local wind probability guidance shows best chances
for seeing frequent 25kt+ gusts will be Wednesday. A period of
4-7ft seas also expected Tue night through Wed, dominated by
short period waves from the NE. Improving conditions for Thu/Fri
as high pressure influences the area.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 7 PM EST Monday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...31
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...DCH
MARINE...MCW/31
Area Forecast Discussion
National Weather Service Lincoln IL
735 PM CST Sun Dec 19 2021
.SYNOPSIS...
Issued at 145 PM CST Sun Dec 19 2021
Quiet weather will prevail across the region this week. Seasonable
temperatures in the upper 30s and lower 40s are anticipated for
the next few days...followed by a big warming trend that will see
readings climbing well into the 50s by Christmas Eve.
&&
.UPDATE...
Issued at 735 PM CST Sun Dec 19 2021
Some low clouds tried edging west from the Indiana border at
sunset, but since then, the cloud deck has significantly eroded to
our east. Thus, overnight sky conditions will generally be
influenced by some thin cirrus streaming by. Winds are expected to
become more steady out of the south later this evening, increasing
to around 10 mph along and north of I-74. This should help keep
temperatures fairly steady overnight in the mid to upper 20s. Main
forecast updates were to decrease the cloud cover over the
eastern CWA, along with some minor temperature adjustments to
reflect the latest trends.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 145 PM CST Sun Dec 19 2021
A sprawling ridge of high pressure currently extending from
Quebec southwestward to Texas will gradually shift eastward
tonight. Despite partly to mostly clear skies, increasing
southerly return flow on the back side of the departing high will
prevent overnight low temperatures from dropping quite as low as
they did last night...with readings mostly bottoming out in the
middle 20s. Once the high moves further away, southwesterly winds
gusting 15-25mph will push high temperatures into the lower to
middle 40s on Monday.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 145 PM CST Sun Dec 19 2021
Zonal flow across the CONUS will allow a series of fast-moving
systems to skirt along the US/Canadian border this week. Given
this particular storm track, any precip associated with the waves
will remain well north of Illinois. The first system will pass to
the north on Monday...pushing a dissipating cold front southward
into the KILX CWA Monday evening. Meanwhile a second wave and its
associated weak front will quickly arrive by Tuesday evening.
Given the far northerly track of the waves and the overall lack of
deep-layer moisture, am expecting little sensible weather other
than a shift in the wind. End result will be dry weather with
seasonable temperatures in the upper 30s and lower 40s Monday
through Wednesday.
After that, a significant short-wave trough is progged to dig into
the western CONUS...resulting in downstream ridging over the
Midwest/Great Lakes. Thanks to rising upper heights and a return
to southerly flow, temperatures will climb well above normal for
this time of year by the end of the week. In fact, highs will
likely soar into the upper 50s to around 60s degrees by Christmas
Eve. While a slight cooling trend is expected by next weekend,
continued zonal flow will ensure any cold/winter air masses
remain locked well to the north across Canada through the
remainder of the extended and beyond.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 513 PM CST Sun Dec 19 2021
Cloud deck just below 3,000 feet is along the Illinois/Indiana
border early this evening. Some associated clouds have tried to
form as far west as KCMI, but seem to be fading recently. An
expanding circle of clear skies near KIND would suggest not a lot
of additional westward expansion, with latest HRRR runs backing
off on the prospects. For now, will only mention SCT clouds at
KCMI and monitor later trends. Otherwise, VFR conditions are
expected across central Illinois through the forecast period.
Southwest winds expected to pick up some on Monday, with gusts
potentially near 20 knots from KPIA-KCMI.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...Barnes
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Northern Indiana
530 PM EST Sun Dec 19 2021
.SYNOPSIS...
Issued at 1247 PM EST Sun Dec 19 2021
Expect a mix of clouds and sun through Thursday under dry
conditions. Temperatures will be around normal, with highs in the
30s and low 40s. The next chances for rain will be Friday into
Saturday, with temperatures climbing into the 50s.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 243 PM EST Sun Dec 19 2021
Building midlevel ridge and associated strong subsidence inversion
has maintained stubborn stratus deck today. Latest hi-res forecast
soundings suggest the trend will continue through tonight and
perhaps into Monday as moisture-laden inversion lowers and holds
firm. Recent satellite trends certainly support this idea with
minimal breaks upstream and there is little to support full
scattering through this evening. Confidence does decrease by
late tonight into Monday though as ridge axis passes and SW flow
ramps back up. 925mb winds veer and increase substantially by 12Z
and GFS and NAM soundings/RH fields suggest (maybe) enough
warm/dry air advection to clear stratus. However, RAP and HRRR are
less optimistic. Trended the forecast much cloudier but still
some room for adjustments in either direction. Also limited
diurnal ranges given last night`s bust on min temps due to
lingering clouds. Expect temps to generally remain in the
30s/upper 20s through tomorrow. No precip.
&&
.LONG TERM...(Monday Night through Sunday)
Issued at 243 PM EST Sun Dec 19 2021
Much of the week will remain dry and quiet with split upper level
flow leaving our area void of sufficient moisture/forcing to support
precip. That may potentially change by late in the week as a
stronger trough ejects out of the western CONUS. Models still
struggling with the details here but latest trends suggest light
precip (if any) and warm enough for just rain.
A dry cold front does pass Tue night and this will lead to slightly
cooler conditions for Wed but temps steadily moderate through the
end of the week. Current NWP suite suggests we may even make another
run at 60F heading into Christmas Eve/Day depending on exact track
and timing of next surface low.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 530 PM EST Sun Dec 19 2021
Threshold VFR cigs early will lower into MVFR cigs overnight as warm
advection strengthens nwwd of dirty ridge axis. Expect this will
persist through much of Monday given intensity of low level thermal
inversion and weak boundary layer moisture advection.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory from 10 PM this evening to 4 PM EST Monday
for LMZ043-046.
&&
$$
SYNOPSIS...MCD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...T
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Area Forecast Discussion
National Weather Service North Platte NE
550 PM CST Sun Dec 19 2021
.SHORT TERM...(This evening through Monday night)
Issued at 327 PM CST Sun Dec 19 2021
An arctic cold front moving through MT this afternoon will push
through wrn and ncntl Nebraska tonight. The arctic air will lift
north of the region Monday night.
The RAP and SREF models suggest a period of stratus associated with
the cold air advection. This stratus moves in tonight and lasts
until 18z Monday according to the RAP model and the short term model
blend. The slower SREF is hanging the stratus across wrn Nebraska
until about 03z Monday night. A low level jet Monday night will lift
the cool air and stratus north of the area according to the SREF
while the RAP and model blend suggest it will mix out Monday
afternoon.
The forecast leans on the short term model blend for sky cover and
temperatures which mixes out most of the stratus Monday afternoon.
The model blend keeps temperatures a degree or two warmer than the
guidance blend in some areas tonight through Monday night. The
strong temperature advections, cold tonight and warm Monday night,
suggest leaning toward warmer temperature forecasts. The forecast
highs in the 20s and 30s Monday is pretty close to the guidance
blend.
.LONG TERM...(Tuesday through Sunday)
Issued at 327 PM CST Sun Dec 19 2021
Although it is still several days away, interest has perked up
regarding the prospect of a 981-983 mb sfc low developing across
SD Friday. The GFS and ECM are very close but with timing
differences- the ECM is faster. The upper level 700mb low tracks
through ND and both ensembles track the sfc low through SD so
confidence is low to moderate for some sort of wind event across
wrn Nebraska- perhaps west northwest winds 30 to 35 gusting over
50 mph as suggested by both models and the statistical guidance.
The models show a srn stream subtropical disturbance, currently
several hundred miles southwest of Baja Mexico, being drawn into the
nrn stream. This appears to energize the 300mb jet to 130-150 kts
and rapidly deepen the sfc low.
The wind forecast uses the 90th percentile of the NBM which is about
10 mph too slow. This weather event is not definite, so for this
forecast the 90th percentile is appropriate.
Otherwise, there are just minor changes in the weather forecast
Tuesday and beyond. A weak Pacific cold front moves through wrn and
ncntl Nebraska Tuesday and temperatures for this forecast were
marked down to 40s to around 50. Temps at the h850mb level are 0C-5C
so a very modest cool down is predicted.
A marked rebound to 10C-12C at h850mb occurs Wednesday and Thursday.
Highs in the 50s to lower 60s are in place these days. The deep low
pressure system Friday will draw cooler air into wrn and ncntl
Nebraska Saturday and Sunday but the magnitude of the cool down is
uncertain. The GFS will drop an arctic front into Nebraska while the
ECM holds the front across SD and waits for additional upper air
support to arrive Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 547 PM CST Sun Dec 19 2021
VFR conditions will continue over the next 24 hours for KLBF and
KVTN. However, ceiling heights will begin to lower tomorrow
morning across the area, possibly reaching MVFR conditions in the
northern Panhandle and western Sandhills. Winds will shift
overnight to the west this evening, then to the north later in the
night. Winds should generally be 10 knots or less.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Meltzer
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
945 PM CST Sun Dec 19 2021
.UPDATE...
Clear skies prevailed across the Midsouth during the early to
midevening, with scattered to broken cirrus approaching north MS.
With light/calm winds, temperatures had cooled to the lower and
mid 30s at 9 PM / 03Z.
Only minor concern overnight is the potential for freezing fog,
particularly over northeast AR and the MO bootheel. This area
received the most rainfall the past few days, will be directly under
the surface pressure ridge center overnight, and will farthest
removed from the aforementioned high clouds to the south. As of
midevening, only Corning`s visibility had dropped, to 6 miles.
00Z HREF depicts little chance of visibility reduction sufficient
to cause ice crystal formation on bridges through sunrise, an
outlook shared by the last several HRRR runs. Nonetheless, latest
forecast update retains a mention for brief freezing fog over
northeast AR, the MO bootheel, and a couple spots in west TN.
PWB
&&
.PREV DISCUSSION... /issued 545 PM CST Sun Dec 19 2021/
UPDATE...
Updated 00z Aviation Discussion.
PREV DISCUSSION... /issued 336 PM CST Sun Dec 19 2021/
DISCUSSION...
The sun has begun to break out across much of the forecast area in
the past hour or so. Temperatures have remained rather chilly this
afternoon, due to overcast skies and moderate CAA throughout much
of the day. Temperatures currently range from the low to 40s with
wind chills in the mid 30s.
Temperatures will fall quickly after sunset under mostly clear
skies. With quite a bit of residual low level moisture in place,
light freezing fog will be possible. The best chance of freezing
fog looks to be over northeast Arkansas and the Missouri Bootheel
after midnight. The current HWO handles this well.
Cool and dry conditions will persist across much of the Mid-South
through midweek as Canadian high pressure remains in place. The
exception will be a quick-moving upper low across the Southern
Plains Monday into Tuesday. This will enhance lift across north
Mississippi and could squeeze out a few light showers. Kept a
slight chance of rain in Monday night into Tuesday.
A warming trend will begin Thursday and persist through the
Holiday weekend. Expect highs to climb into the mid to upper 60s
each day. Models are in reasonable agreement on a slow-moving cold
front dropping into the Mid-South Christmas weekend. Rain chances
could return by the end of the Holiday weekend. A broad trough
looks to setup over the western CONUS to begin the following week.
This may translate to an unsettled pattern to end the year.
AC3
&&
.AVIATION...
/00z TAFs/
Clouds have finally scattered out this evening. Winds remain
northerly at 7 to 10 kts but should become light in the next few
hours. VFR conditions will persist bit patchy fog or freezing fog
is possible near the river. Otherwise, conditions are perfect for
flying!
SWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Melbourne FL
1051 PM EST Sun Dec 19 2021
.UPDATE...
Current radar imagery shows most of the precipitation has exited
east-central Florida for now. Only a couple of isolated showers
remain over the far offshore Treasure Coast waters as an area of
weak low pressure has stalled just off the northeastern Florida
and Georgia coasts with the associated weak frontal boundary
stretching over the local Atlantic waters and into southern
Florida. Moisture will continue to pivot on the back side of low
pressure through the period ahead of a strong cold front that will
approach the region by Tuesday. While much of the area should
remain dry overnight, increased moisture and lift over the region
will keep isolated-to-scattered showers in the forecast through
the morning hours. The best chance for rain will remain over the
local Atlantic waters with diminishing chances towards the coast
and mostly dry inland through at least mid morning. Isolated
embedded lightning strikes will remain possible mainly over the
Gulf Stream. Low temperatures are on track to drop down into the
low 60s to near 70s degrees overnight.
&&
.PREV DISCUSSION... /issued 256 PM EST Sun Dec 19 2021/
Current-Tonight...Since this morning, the weak cold front that was
anticipated to sweep through the local area this afternoon has
slowed to a crawl, still analyzed west of Tallahassee as of 4pm.
Even so, the forecast this afternoon should remain largely
unchanged, with only real difference in possible timing and coverage
of additional shower activity through the early evening. Over the
last few hours, radar has quieted down with only isolated sprinkles
over the far interior; however, things are starting to pick back up
with a training line developing over Palm Beach County. Latest HRRR
runs indicate the front reaching Lake County prior to sunset, with a
pocket of showers and isolated storms shifting alongside the
boundary, exiting towards the Brevard County coast prior to
midnight. Behind the front, west winds will veer northwesterly and
then northerly just prior to daybreak. Lows will continue with the
well above normal trend in the low to mid 60s. Warm temps and high
dewpoints could enhance the potential for fog, but so far, all signs
look to keep reduced visibility south of Lake Okeechobee for the
predawn hours, however another round of low stratus will be possible
overnight.
Monday...By tomorrow, the front is expected to stall over south FL
with a robust system exiting TX which will bring unsettled weather
on Tuesday. A closed 500mb low treks across TX to the LA Gulf coast
early in the day tomorrow, with a closed surface low trailing along
the end of the frontal boundary, dragging across the Gulf of Mexico
through the afternoon. Moisture will remain high along the stalled
boundary already over FL, then increase further with the approach of
this Gulf system to the west central FL coast (Tampa Bay). As a
result, rain chances Monday will steadily increase through the day
most likely favoring the Atlantic waters and coastal locations at 40-
50%; 20-30% for interior locations. While most activity will remain
as passing showers, a few cells could produce occasional lightning
strikes, especially over the waters and immediate coastline east of
I-95 through the afternoon. The main limiting factor will be
excessive cloud cover which will keep highs about 5 degrees cooler
in the low to mid 70s to near 80s for the Treasure Coast.
Mon Night-Tue night (previous modified)...An area of low pressure
over the eastern Gulf of Mexico on Mon night will be pushing to
the northeast and reach the west coast of FL by Tue morning and
cross the peninsula during the day. Ahead of the low, a warm front
will also be lifting across the FL on Mon night. Aloft, a mid
level low over eastern TX on Mon night will move east along the
northeast Gulf Coast then across northern FL Tue-Tue night, with a
short wave trough axis extending southward through the peninsula.
Strong jet forcing ahead of the low will induce surface
cyclogenesis over the central GOMEX Mon, which then slides E or
ENE across central or NOFL between Tue afternoon-Tue night.
Differences show up in the op- model solutions with respect to
timing, track and especially strength of the GOMEX low. Of note,
the ECM and GFS are now coming to a better agreement on speed and
location of the low. This places the entire peninsula in its warm
sector, with stronger low level winds/greater instability leading
to a more robust severe TS threat over ECFL.
Regardless, cloud cover and rain chances rise significantly on Mon
night into Tue, owing to increasing deep layer forcing, including
upglide along the northward advancing surface warm front late
Mon- early Tue. Chance POPs are likely- categorical for all but
the far south Mon night, then categorical areawide Tue with the
approach and passage of the attendant surface front, with
scattered showers lingering into the evening, before the rain
shifts rapidly offshore. As the low lifts to the northeast on Tue
evening/night, east central FL could find itself on a drier spot
being the firsts to see a decrease in shower coverage.
Lows on Mon night will only drop to the 60s. Clouds and showers
will keep the max temps on Tue below 80, with maxs of mid 70s
across the northern counties. Then for Tue night, temps will be
cooler, dropping back to lower 50s north and mid-upper 50s south.
Wednesday-Saturday (previous modified)...Short wave trough along
the SE seaboard Wed morning will eject rapidly NE over the
Atlantic with a broad trough left in its wake, shifting offshore
Wed night. A broad mid level ridge will build eastward across the
GOMEX and FL through the remainder of the week. This will lead to
an extended period of dry weather into the weekend. Temps will be
on the cooler side on Wed only reaching the mid 60s/lower 70s with
lows that night dropping to the mid 40s/lower 50s. From Thu on,
temps will warm up through the weekend reaching the 70s on Fri and
upper 70s by Sun.
&&
.AVIATION...
A very slow return to VFR took most of the morning and early
afternoon for several terminals, as stubborn stratus retained MVFR
cigs until nearly 18Z. Most clouds have since cleared, with a few
low and mid level clouds remaining this afternoon. A weak cold front
is currently positioned just west of KTLH and is expected to cross
the local area later this evening and overnight then stalling across
south FL tomorrow. Isolated shower will stream across the area until
sunset, so mention of VCSH will suffice. Behind the front, west
winds will veer northwest and then north by daybreak, increasing to
near 12 knots. An approaching system across the Gulf will raise rain
chances tomorrow afternoon, most favorable for coastal terminals.
&&
.MARINE...
Tonight-Monday...West winds up to 10 knots this afternoon will veer
northwest then north overnight, increasing to 15 to 20 knots north
of the Cape as a cold front passes over the local waters overnight.
With the wind surge, seas will rapidly build from 3-4 ft currently
up to 6-8 ft by mid morning Monday, spreading south along all
offshore zones. Showers and thunderstorms will be possible overnight
as the front passes, with higher coverage tomorrow ahead of a
stronger low pressure advancing eastward across the Gulf of Mexico.
Small craft in the offshore Volusia waters should exercise caution
tonight as increasing winds and seas will arrive prior to sunrise,
with a Small Craft Advisory effective for all offshore zones by mid
morning.
Mon Night-Wed night...As a low pressure approaches the local
Atlantic waters on Mon night, northeast winds on Mon night will
remain in the 15-20 kt range with seas 5-8 ft in the offshore
waters. These should start to subside through the night and Tue
morning. Marine conditions will remain hazardous as the pressure
gradient remains tight with winds increasing again on Tue night
followed by building seas as well.
Thu-Fri...
By Thu, the low pressure will be over the western Atlantic with a
high pressure building over the eastern coast of the US. Through
the end of the week, seas will slowly subside with winds
decreasing as well from 15 kt on Thu from the north to less than
10 kt on Fri.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 82 64 74 63 / 40 30 50 80
MCO 84 66 77 66 / 40 10 30 80
MLB 83 66 79 65 / 40 30 40 80
VRB 85 67 81 67 / 40 30 40 80
LEE 83 65 75 64 / 40 10 30 80
SFB 84 65 76 65 / 40 20 40 80
ORL 84 65 77 65 / 40 10 40 80
FPR 83 66 80 65 / 40 30 40 80
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 10 AM Monday to 7 AM EST Tuesday for
Flagler Beach to Volusia-Brevard County Line 20-60 nm-
Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.
&&
$$
Fehling/Kelly
Area Forecast Discussion
National Weather Service Marquette MI
659 PM EST Sun Dec 19 2021
.SHORT TERM...(This evening through Monday)
Issued at 349 PM EST SUN DEC 19 2021
RAP analysis shows a sfc high pressure system stretching from Texas
to James Bay this afternoon with a shrtwv and associated low
pressure system shifting east over Lake Winnipeg. Mid- to upper-
level clouds are streaming in from the west under zonal flow as a
50kt LLJ shifts east through the Upper Midwest. Starting to see a
few gust reach the sfc here and there, but WAA is increasing
stability some. As the day goes on into this evening, gusts should
become more frequent, especially along any southerly downslope
favored locations and the higher terrain, with low to mid 20mph
range everywhere and around 30mph for the favored locations.
Tonight, LLJ will shift overhead as sfc low pressure passes to the
north of Lake Superior. Gusts will continue through the overnight
hours before starting to weaken through the morning and afternoon on
Monday. Despite the WAA and isentropic ascent early tonight,
moisture is too limited to include PoP mentions across the majority
of the UP. There is a small chance of some lake-enhancement across
the far east under SW flow; however, DGZ saturation is limited at
best, so could end up seeing a little bit of fzdz instead. For now
have both -shsn and isolated fzdz in the fcst...accumulations are
expected to be minimal if any. The Keweenaw has a chance to see some
pcpn as well tonight as the wave passes to the north and cold front
approaches. Again, dry low level air will be another limiting
factor, so -shsn/fzdz would remain on the lighter side. With
overcast skies and CAA/breezy conditions, lows tonight will be
mostly advectively driven, falling to around 20 west half and mid
20s east.
By tomorrow morning, cooler air will continue to move in from the
west as inversions raise slightly. Prior to some LES starting across
the Keweenaw and NW wind snow belts, there could be some light fzdz.
By midday, 850mb temps fall to around -16C, but inversion heights
will remain shallow to around 4kft across the west and 5kft across
the east. We should still see some light LES in the NW wind snow
belts, but accums will suffer with lower inversion heights. With
increasing CAA, high temperatures will be early and then will fall
into the low teens through the day, potentially single digits west
by dinner time.
.LONG TERM...(Monday night through Sunday)
Issued at 142 PM EST SUN DEC 19 2021
Upper air pattern will consist of a 500 mb low off the west coast
and a broad and flat trough across the northern U.S. 00z Tue. A
shortwave moves into the upper Great Lakes later on Tue. Deeper
moisture and dynamics move in on Tue and move out Tue night.
Did not make many changes to the going forecast except lingered some
pops in for lake effect snow showers Tue night into Wed.
In the extended, the GFS and ECMWF show a 500 mb trough on the west
coast 12z Thu with a shortwave in the upper Great Lakes region.
Troughing moves into the Rockies 12z Fri with a shortwave affecting
the upper Great Lakes 12z Sat. Troughing moves onto the west coast
12z Sun. Active and fast pattern will continue with weak systems
passing through the area for this forecast period. Temperatures will
be above normal for this forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 655 PM EST SUN DEC 19 2021
VFR conditions will persist through this evening at all terminals.
As a low pressure system approaches and passes to the north of Lake
Superior tonight, a period of LLWS is possible at all terminals. As
an associated cold front crosses the UP behind the low, LLWS will
come to an end with gusty conditions prevailing through Monday
afternoon. Conditions will fall into MVFR behind the cold front,
with light snow chances at CMX and SAW.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 349 PM EST SUN DEC 19 2021
As a 50kt LLJ moves overhead tonight, expect SW gales to 40 knots
across the lake. Increasing stability with some WAA, should limit
the gusts to around 40 knots or so, but could see a few gusts sneak
into the low 40kt range. A cold front will then pass over the lake
late tonight, with NW gales of 35 to 40 knots across the central and
east. Could see some moderate freezing spray as well with the
stronger winds and colder temps. The wind falls below 20 knots on
Monday night and then northwest winds of 30 knots or so are expected
Tuesday night. The active pattern will continue through the rest of
the week into Christmas Weekend with a series of ridges and troughs
passing over the lake.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Lakeshore Flood Advisory until 7 AM EST Monday for MIZ013.
Lakeshore Flood Advisory from 10 PM this evening to 9 AM EST
Monday for MIZ014.
Lake Superior...
Gale Warning until 4 AM EST /3 AM CST/ Monday for LSZ162-266-267.
Gale Warning from 10 AM to 7 PM EST Monday for LSZ249>251-
265>267.
Gale Warning until 7 AM EST /6 AM CST/ Monday for LSZ240>244-263-
264.
Lake Michigan...
Gale Warning until 7 AM EST Monday for LMZ221-248-250.
&&
$$
SHORT TERM...JAW
LONG TERM...07
AVIATION...Voss
MARINE...JAW
Area Forecast Discussion
National Weather Service San Francisco Bay Area
402 PM PST Sun Dec 19 2021
.SYNOPSIS...Dry and cool today. Potential for patchy frost and
fog will return Monday morning. A wet weather pattern will
dominate the work week and through the holiday weekend. Expect
intermittent periods of moderate rain during that time frame as
several waves of precipitation move inland. Cool and unsettled
conditions, with rain at times, are then projected to continue
early next week.
&&
.DISCUSSION...as of 03:15 PM PST Sunday...Another cool and mild
afternoon with cloudy skies across the North and East Bays and
partly cloudy skies around portions of the Monterey Bay region. As
we approach the early morning hours of Monday, expect the
potential for fog and isolated areas of frost...may even see a bit
of freezing fog in cold mountain valleys.
As advertised in prior discussions, Monday will be the transition
day as we enter a wet pattern that will dominate the holiday week
and weekend starting Tuesday. Extended models suggest that the
potential for additional rain could continue into early next week
as well. The high resolution models (NAM 3km and HRRR 3km) along
with the ECMWF & GFS ensembles are hinting that we may see light
rain or drizzle as early as Monday afternoon or evening for the
coastal areas of the North Bay. However, no significant impacts
are expected beyond slick roads.
A low pressure storm will be centered over the Pacific Ocean
Monday into Tuesday near 40 N, 135 W (west of the OR/CA border). The
ensembles and deterministic models continue to suggest that
moderate rain will likely not arrive until Tuesday
morning/afternoon as it spreads east and southward across our CWA
for the rest of the day into Tuesday night. On Wednesday, that low
weakens and gets absorbed into a trough pattern extending from
Western Canada and southward over the Pacific Ocean offshore from
the US west coast. During the trough pattern, additional waves of
rain will move inland through Thursday. By Friday, that trough
pattern broadens as additional rain continues in our region,
however, models suggest that periods of moderate rain are more
likely Tues-Thurs while lighter rain is likely Friday into the
weekend. The caveat here is that this may change as the forecast
models update during the week.
One of the trends we`ve noticed is that as we add more days of
rain to our storm total, we`re not seeing much change in those
storm totals for the North Bay into the Bay Area. This suggests
that the intensity of this storm is backing off. Also, this could
mitigate major precipitation impacts since the same amount of rain
is now spread out over more days. But it`s still wise to be
prepared as details are still vague for the end of this week into
early next week. Impacts you should be prepared for are:
- hazardous roads due to slick conditions and increased holiday
traffic
- ponding of roadways and off-ramps
- minor flooding in low-lying areas and where there is poor
drainage
- stay alert for the potential of burn scar debris flows and/or
mudslides in case rain rates do become intense
- rises in creeks and streams, however, main stem rivers should
remain below flood levels
- if you plan to travel into higher terrain (ie Sierra Mountains)
then check road conditions and have chains/emergency supplies in
your vehicle
Total Rain Amounts have trended down a bit since the midnight
shift last night. Here is our latest update of rain total
estimates from Monday, Dec 20 through the morning of Sunday, Dec
26:
-Coastal peaks in the North Bay: 4 to 6"
-The Santa Cruz Mtns and Northern Monterey Bay: 3 to 5"
-The Santa Lucia Mtns and the Big Sur Coast: 3 to 6"
-Interior North Bay: 2 to 4"
-Around the SF Bay (including East & South Bay): 1 to 3"
-Southern/Eastern Monterey Bay and San Benito County 1 to 3"
-Salinas Valley 1.5 to 2.5"
A reminder that additional rainfall is likely after Sunday the
26th which would add to these totals, but confidence is low on how
much more.
&&
.AVIATION...as of 3:50 PM PDT Sunday...For the 00Z TAFs.
Cigs have mostly lifted to above 3,000 feet this afternoon, but
MVFR cigs sticking around in the North Bay and East Bay. Low
clouds could scatter out even more with the remaining daylight
hours, but MVFR cigs likely to make a return for all terminals
again tonight through early Monday morning. North Bay terminals
likely to have be IFR at times as well.
Expect less fog and/or low visibility overnight into Monday
compared to previous mornings as MVFR is likely. At this time,
precipitation chances are likely to remain beyond the current TAF
period but OVC skies through TAF period. South/SE winds between
8-12 kts possible and locally gustier expected Monday afternoon
through evening.
Vicinity of KSFO...VFR but teetering at MVFR through the daylight
hours. Light onshore winds for the remainder of the
afternoon/evening. Southerly winds expected tomorrow afternoon and
increasing to up to 12 kts. MVFR likely tonight with VFR Monday
afternoon as cigs should lift to above 3,000 feet.
KSFO Bridge Approach...Similar to KSFO.
Monterey Bay...Stratus trickling into MRY bringing MVFR cigs. Winds
out of the SW at MRY and NW in SNS around 8-10 kts but both
terminals will shift southeasterly tonight. MVFR conditions are
expected with increasing moisture across the region. SNS will have
breezy SE winds up to 15 kts possible into Monday morning. Cigs
will lift but OVC skies expected through TAF period.
&&
.MARINE...as of 02:51 PM PST Sunday...A low pressure system off of
the West Coast will strengthen during the week while remaining
nearly stationary until mid-week then will slowly advance toward
the coast late week. This system will bring increasing southerly
winds and rain to the coastal waters and bays beginning early
this week. A Gale Warning is in effect for the northern outer
waters Monday afternoon through late Monday night. Wet weather
will likely continue through Christmas along with showery,
unsettled, colder weather conditions during the holiday weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm from 3 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm from 3 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 9 PM
SCA...Pt Arena to Pt Reyes 0-10 nm
&&
$$
PUBLIC FORECAST: Bingaman
AVIATION: McCorkle
MARINE: RGass
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