Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/19/19
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
935 PM EST Mon Nov 18 2019
A couple of weak low pressure areas will move across the local
area through Tuesday night. High pressure gradually builds in
from the west for Wednesday and Thursday. A cold front crosses
the region late Friday into Saturday.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 935 PM EST Monday...
Latest weather analysis reveals a rather compact, quick moving
shortwave pivoting sw to ne up into the northern Mid-Atlantic.
Regional radar mosaic showing light rain similarly lifting up
north of the I-64 late this evening, with only some lighter
showers/patchy drizzle along and east of I-95. Partial clearing
behind this line was short-lived, with low stratus redeveloping
as the rain moved out of the SW piedmont zones. Given light
flow and plenty of llvl moisture, would expect fog currently
<1sm just e of LYH and nudging into our western tier of counties
to expand in area overnight across the piedmont. Several
successive runs of LAMP guidance...as well HRRR and the HRRR
time-lagged showing VIS <1SM west of RIC overnight. Have issued
an SPS for now for a small tier of SW counties along and west
of I-85...and may need a Dense Fog Advisory eventually tonight
inland if current trends hold. Otherwise, rain will taper off
overnight, with clearing likely delayed until Tuesday morning.
Partly to mostly cloudy with areas of fog (especially inland).
Lows in the 30s...around 40/low 40s along the coast.
As of 300 PM EST Monday...
Low clouds remain stubborn over much of the local area this
afternoon. There has been a bit of partial clearing into parts
of central VA ahead of a S/W approaching from the central mtns/wrn
NC. Will have a rather large area of SHRAS move (SW-NE) across
the FA this evening...PoPs 50-80%. Highest PoPs shift NE toward
the coast while decreasing in coverage overnight. Otw...mostly
cloudy w/ light winds. Patchy FG cannot be ruled out as well.
Lows in the l-m30s I 95 corridor and W to the l40s near the
coast in SE VA-NE NC.
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
As of 300 PM EST Monday...
A break in wx systems is expected Tue. Models suggest significant
clearing may be troublesome but will expect at least breaks in
the clouds w/ PoPs mainly blo 10%. Highs in the m-u50s.
Final piece of the upper level trough to cross the region Tue
evening-night. Blend of the guidance shows at least SLGT CHC
PoPs (SHRAS) over the FA along w/ lingering cloudiness. Lows
from the u30s W to the m40s at the coast in SE VA-NE NC.
Finally by Wed...NW flow aloft and sfc hi pres building in from
the W/SW will allow for a mostly sunny day (partly sunny NE).
May be be a tad breezy...esp at the coast/on the ern shore.
Highs Wed again in the m-u50s. Mainly clear Wed night with lows
30-35F well inland to the u30s-l40s at the coast. Dry/seasonable
wx continues Thu as sfc hi pres settles to near the NC/SC
coasts. Highs 55-60F.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 310 PM EST Monday...
The extended portion of the forecast turns more unsettled...esp
late Fri into early Sun. ECMWF/GFS coming more in line wrt a
cold front crossing the region w/ possible SHRAS (late Fri/Fri
night)...then lo pres/its associated cold front...quickly
returning by late Sat (w/ additional RA chcs) and exiting early
Sun. Drying out by late in the weekend and for Mon. Lows Thu
night ranging through the 40s. Highs Fri in the l-m60s N and
m-u60s S. Lows Fri night in the l-m30s N and W to around 40F at
the coast in SE VA-NE NC. Highs Sat 50-55F. Lows Sat night in
the l-m30s W to the l40s far SE. High Sun from the l50s N to the
u50s far SE. Highs Mon ranging through the 50s.
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
As of 730 PM EST Monday...
IFR-MVFR CIGS (some LCL LIFR just to the west of the local
area) across area terminals to begin the 00z TAF period.
Showers in association with quick moving upper disturbance are
pivoting through the area this evening and will exit from SW to
NE by around midnight, possibly lingering past 06z at KSBY. CIGS
briefly bump back to MVFR/VFR in rain, then drop back down into
LIFR/IFR range as precipitation clears out. Expect LIFR/IFR
CIGS across area terminals overnight, with areas of fog. Some
LIFR VSBY possible late tonight into the overnight especially
west of RIC.
Starting out w/ IFR/low-end MVFR conditions Tue then BKN VFR
CIGS expected by afternoon. The final piece of the upper level
trough will cross the region Tue night w/ another round of
MVFR CIGS and ISOLD SHRAS possible. VFR conditions will then
prevail after early Wed morning and last into the late week
As of 345 PM EST Monday...
N-NW winds have fallen to 10-15 kt this aftn as low pressure
well offshore of the Northeast US coast continues to pull away from
the region (w/ not much of a pressure gradient across much of the
central/ern CONUS. As a result, SCAs are now only in effect for the
ocean/Lower Ches Bay for waves/seas (due to swell from the departing
system). The SCAs for the ocean continue through 23z/6 PM Tuesday.
The SCA for the Lower Ches Bay zone (ANZ632) has been extended until
00z/7 PM this evening, while the SCA for the mouth of the Ches Bay
runs until 06z/1 AM Tuesday. Winds turn to the W and diminish to 5-
10 kt tonight as the aforementioned low continues to pull away from
the region. Winds generally remain out of west at 5-12 kt
(sustained) through late Tue evening. Low pressure develops well
offshore of the Mid-Atlantic coast Tue evening before deepening and
tracking to the NNE during the Tue night-Wed timeframe. Winds turn
to the NW Tue night and increase to 15-20 kt on the bay/ocean due to
an increasing pressure gradient on the back side of the deepening
coastal low (w/ high pressure centered from the srn Great Lakes to
the Deep South). Wind gusts are expected to be around SCA criteria
on the bay/ocean from late Tue night-Wed before slowly diminishing
by early Thu AM as high pressure becomes centered over VA/NC.
Seas have slowly diminished today, and are now 7-11 ft offshore with
waves in the Ches Bay in the 2-4 ft range (up to 5 ft at the mouth).
Seas likely remain above 5 ft through late Tuesday (thus the SCA
remains in effect through Tue evening). In addition, waves near the
mouth of the bay will most likely remain above 4 ft through late
tonight. Extended the High Surf Advisory until 10 PM this evening,
as seas are still ~8 ft nearshore in most places S of the VA-MD
As of 345 PM EST Monday...
Widespread minor flooding is occurring/has occurred across the area
with the current high tide cycle. Tidal anomalies are around 2
ft across the Lower Ches Bay/tidal rivers. Anomalies have risen
this aftn from Lewisetta to the bayside of the Lower MD Ern
Shore due to a relatively strong flood tide (slightly higher
than the 12z CBOFS forecast). As a result, widespread minor
tidal flooding is expected to continue through this evening
across the upper Ches Bay. Water levels at Bishop`s Head will
likely crest just above moderate flood thresholds (~3.8 ft).
No additional tidal flooding is expected across the Lower Ches
Bay/ocean after the current high tide cycle (with the exception of
minor flooding at Bayford during tonight/Tuesday`s high tide cycle).
Therefore, all Coastal Flood Advisories for areas S of Windmill
Point will be allowed to expire after the current high tide
cycle (00z this evening). Anomalies are forecast to remain
relatively steady across the upper Ches Bay from tonight-Tue.
Therefore, the threat for mainly minor coastal flooding will
continue through Tue from the tidal Potomac/VA Nrn Neck to the
bayside of Lower MD Ern Shore. For now, will extend the Coastal
Flood Advisories through tonight for the bayside of the Lower MD
Ern Shore/VA Nrn Neck, and will let the midnight shift assess
coastal flood potential for the high tide Tue. Will likely need
to extend the advisory through Tue evening for the bayside of
the Lower MD Ern Shore (at least). Could see water levels
approach moderate flood thresholds at Bishop`s Head during the
high tide on Tue (like what is happening this evening), given
that it is the higher of the two astronomical tides.
Increasing NW winds Tue night-Wed should allow tidal anomalies to
finally fall across the upper Ches Bay, ending the threat for
coastal flooding after Tue evening.
MD...Coastal Flood Advisory until noon EST Tuesday for MDZ021>023.
NC...High Surf Advisory until 10 PM EST this evening for NCZ102.
VA...High Surf Advisory until 10 PM EST this evening for VAZ098>100.
Coastal Flood Advisory until 10 AM EST Tuesday for VAZ075-077-
MARINE...Small Craft Advisory until 1 AM EST Tuesday for ANZ634.
Small Craft Advisory until 6 PM EST Tuesday for ANZ650-652-654-
Area Forecast Discussion
National Weather Service Burlington VT
832 PM EST Mon Nov 18 2019
Patchy drizzle or freezing drizzle this evening, then a mix of
freezing rain and sleet moving into western Vermont and northern
New York during the evening and overnight hours. This mix of
precipitation will change over to snow prior to sunrise on
Tuesday and will gradually taper off during the afternoon hours
on Tuesday. Quieter weather is expected on Wednesday and
Thursday but another storm system will move into the region on
Friday. This system will likely bring a mix of rain and snow to
the North Country.
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 832 PM EST Monday...The forecast remains largely on track
in advertising a light mixed precipitation event to unfold
tonight through Tuesday morning. As such, only nominal changes
were made as of mid-evening, most notably by adjusting overall
QPF downward by about 25% per latest blends, operational NAM/GFS
and WPC output. Latest data suggests a persistent warm nose of
1-4C remains atop our region near 850 mb and this is confirmed
by recent observational data from Mt Mansfield and Whiteface Mtn
as well as ACARS data out of CYUL. The devil is in the details
of course, with most recent GFS and HRRR ouput holding on the
warm nose through the overnight hours with less light snow and
more -fzra/pl while the NAM cools this layer to around freezing
suggesting more of a transition to light snow later tonight.
Latest trends would suggest the former (i.e. more mix and less
snow except on the western fringes of the pcpn shield across nrn
NY) but given accumulations of both snow and ice are on the
light side there`s no need to make such noise-level changes at
this point. Bottom line, mixed pcpn and light icing is still
expected overnight into Tuesday morning making for a potentially
slick morning commute. Have a great evening.
Winter Weather Advisory continues for Rutland, Orange, and
Windsor Counties in Vermont and will take effect at 6 PM for the
rest of Vermont and much of Northern New York. The forecast
remains on track with minor tweaks. The first is the expectation
for more a drizzle or freezing drizzle at the onset favoring
areas east of the Greens where easterly 850mb flow will advect
low to mid-level moisture from a coastal system passing east of
the benchmark. As flow turns more northerly and more moisture
expands over the rest of the advisory area later this evening,
we should see additional drizzle/freezing drizzle reports. A
second system crosses the region during the pre-dawn areas of
Tuesday with an additional bout of a wintry mix and briefly
moderate wet snow.
Light radar returns are starting to sneak up the Champlain and
Connecticut Valleys. Given the drizzle will be low to the ground,
anticipate this will make it hard for the radar to sample east of
the Greens. Temperatures warmed a bit further than expected reaching
the mid to upper 30s. They have since leveled off and should begin
to fall once cold air advection begins to take effect in the next
hour or so. As temperatures cool tonight, the concern will be
intermittent freezing drizzle leaving a glaze across untreated
surfaces as temperatures fall into the mid 20s to lower 30s. The
bulk of the precipitation occurs during the pre-dawn hours on
Tuesday as a compact shortwave rounds the base of an upper trough
positioned along the Great Lakes. The North Country will be
positioned in the left exit region of a jet streak along this
compact embedded trough with a narrow area of strong ascent.
Overall, sharp FGEN/deformation remains south of the region before
lifting northeast and weakening as it grazes our eastern areas. It
remains a challenging forecast though, with a handful of models
placing the strongest forcing over our region instead. Anticipate a
sharp QPF gradient with this shortwave. One of the potential
predicaments with missing this strong forcing is the lack of any
dynamical cooling it would yield. The 12Z GFS and a few HRRR runs
have come in with little to no transition to snow as the warm nose
remains in place. In general, the forecast still reflects a glaze to
a tenth of an inch of ice accumulation, and wet snow adding a
dusting to 1" over much of the North Country, and then 1-3
inches in the Northeast Kingdom.
Precipitation comes to an end Tuesday afternoon/evening. There is
not much of a change in air mass overnight, and there will be some
high-level clouds keeping temperatures in the 20s overnight. Yet
another upper trough begins to lift northward overnight. Without
much moisture, anticipate mainly upslope showers along northwestern
slopes to begin developing into Wednesday.
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 332 PM EST Monday...Wednesday will be mostly cloudy with
some light snow showers around the area. An upper-level low will
lift over coastal New England during this time frame, enhancing
synoptic-scale ascent and marginally increasing low-level
instability. With limited moisture however, accumulations will
be limited to a dusting if anything for lower elevations, and up
to a couple tenths of an inch for higher elevations of northern
Vermont. High temperatures will again be in the 30s, lows in
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 332 PM EST Monday...A low pressure system will track
northeastward through Quebec Friday, dragging a series of fronts
through the North Country as it progresses northeastward.
Friday morning, the system`s warm front will move through,
supporting some spotty morning shower activity. The system`s
cold front won`t move through until sometime late Friday
afternoon through early Friday night. At this point, nothing
looking too concerning about the system impact-wise, looks to
for the most part just a be run-of-the-mill system typical of
fall in New England. Early indications looking like an inch or
less of precipitation, but this will be dependent on low track
and other factors that could change. Still too early to nail
down precipitation type, but at this point thinking it`ll start
as rain (highs Friday currently forecast in the 40s) and then
transition to some snow on the back side of the system. Will see
some post-frontal clearing Saturday with some gusty winds
developing and cooler temperatures. From Sunday onward, models
differ quite significantly in the evolution of the next low
pressure system to move out of the southeastern US.
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...Deterioration to mainly MVFR/IFR over
the next 24 hours as upper low pressure and light mixed
precipitation moves through the region. Winds light and less
than 10 kts through the period. Precipitation type quite
tricky, with patchy -ra/-fzdz from 00-04Z transitioning to a
general -fzra/pl mix, then light snow/pl in the 04-12Z time
frame. Light mixed precipitation lifts out of the area in the
14-18Z time frame. Only exception will be KMSS where pcpn will
be patchy/intermittent at best so only VCSH there.
Given higher confidence of at least some patchy -fzdz/-fzra
later tonight into tomorrow morning, runway treatment and de-
icing operations will be likely where applicable.
Tuesday Night: MVFR/IFR conditions possible. NO SIG WX.
Wednesday: Mainly MVFR, with local IFR possible. Slight chance
Wednesday Night: MVFR/IFR conditions possible. Slight chance
Thursday: Mainly VFR, with local MVFR possible. NO SIG WX.
Thursday Night: VFR. Definite SHRA, Likely SHSN.
Friday: Mainly MVFR, with areas IFR possible. Likely SHRA, Likely
Friday Night: Mainly MVFR, with local VFR possible. Chance SHRA,
Slight chance SHSN.
Saturday: Mainly VFR, with local MVFR possible. Slight chance
VT...Winter Weather Advisory until 1 PM EST Tuesday for VTZ001>012-
NY...Winter Weather Advisory until 1 PM EST Tuesday for NYZ027-028-
Area Forecast Discussion
National Weather Service Duluth MN
541 PM CST Mon Nov 18 2019
Issued at 540 PM CST Mon Nov 18 2019
Updated for the 00Z Aviation discussion.
.SHORT TERM...(This evening through Tuesday night)
Issued at 323 PM CST Mon Nov 18 2019
A 500-mb short wave trough with 850-mb warm air advection will
slide east from the Dakotas into Minnesota tonight. At the
surface, a warm front will move through the region from west to
east. Precipitation is expected to develop tonight into Tuesday
morning as this system moves through. There are some slight
differences in timing, but generally the models are consistent
with bringing in precipitation to our western county warning area
around or just after 6 pm tonight, reaching the Twin Ports and
Iron Range after midnight. The best forcing for this system in
terms of upper level cyclonic vorticity advection and
frontogenesis appear to be in central and southern Minnesota, so
higher PoPs are generally to the south and west. Precipitation
type will be an issue especially from Pine County to the Brainerd
Lakes area and going north towards the International Border. Here,
surface temperatures will likely hover around or just above
freezing. Model soundings from the RAP and HRRR suggest a
rain/snow mix becoming rain and perhaps ending as drizzle as drier
air moves in aloft and ice crystal growth diminishes. Further
north from the Twin Ports to the Iron Range and the Arrowhead,
most of the precipitation should fall as snow with surface
temperatures around freezing and temperatures aloft sufficiently
colder. With the highest QPF expected further southwest where more
rain may mix in, however, not expecting any snowfall totals much
higher than an inch to perhaps an inch and a half across the
region. Patchy freezing drizzle will be possible tonight as well,
but expecting ice accumulations to be minimal. With warm air
advection and mixed precipitation going on, would not be surprised
to see some patchy fog tonight as well.
Mixed precipitation will gradually taper off from southwest to
northeast on Tuesday with temperatures warming into the mid 30s
for most locations. Low level moisture will linger, however, which
will keep clouds around. Brief high pressure with upper level
ridging will provide a break from precipitation, but the next
short wave will start to approach the area from the west late
Tuesday night into Wednesday morning.
.LONG TERM...(Wednesday through Monday)
Issued at 323 PM CST Mon Nov 18 2019
A brief period of ridging Wednesday morning, then an upper level
trof moves into the Dakotas in the afternoon. Ahead of this trof,
a weak surface trof moves into Minnesota. A fairly sizable omega
field associated with this surface trof will generate some
precipitation. Warm air advection ahead of these features will
lead to mixed precipitation. Will keep the freezing
drizzle/drizzle mention that was inherited from the previous
shift. This scenario continues Wednesday night, but without the
warm air advection. A surface low will grow as it moves from
western Nebraska to central Iowa. The surface trof will remain
fairly stationary over the forecast area, but will see some cold
air advection on the backside. The liquid precipitation will
change over to snow in northeast Minnesota, but be mixed with some
light freezing drizzle. Not expecting any ice accumulation, but
some spots may have a light glaze.
On Thursday, the surface low moves into the central Great Lakes,
while a tight, fairly strong upper trof moves into northern
Minnesota. Will continue to see the mixed precipitation in the
morning, but diminishing from west to east as the day progresses.
There will be less freezing drizzle as there is more ice aloft,
which leads to a bit more snow. Snow amounts will be light
Wednesday through Thursday, but a general 1 to 2 inches is not
unreasonable. A period of light lake effect snow is possible
Thursday evening as a northwest flow over Lake Superior combines
with some weak cold air advection. Minimal accumulation Thursday
evening. The upper trof departs Thursday night. High pressure
builds in at the surface and turns the flow westerly ending the
lake effect. The high will be nearby Friday through Sunday.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 540 PM CST Mon Nov 18 2019
A low pressure system will push a warm front across the area
tonight and Tuesday. Currently we have a mixture of MVFR/IFR
ceilings and VFR visibilities, which should deteriorate over the
next 3 to 6 hours to predominantly IFR ceilings. A mixture of drizzle,
rain or snow should spread in to also drop visibilities to
MVFR/IFR for several hours, mostly between 03z and 16z depending
on location. The IFR ceilings are expected to linger through the
end of the TAF period, with VFR visibilities.
Issued at 323 PM CST Mon Nov 18 2019
An area of low pressure will move through the region tonight and
Tuesday which will bring a wintry mix of rain and snow to western
Lake Superior. Winds are expected to be relatively light during
this time, from the south at 5 to 10 knots this evening veering
southwest overnight and Tuesday and increasing to 5 to 15 knots.
Hazardous conditions are not anticipated during the next 48 hours.
Another low pressure system will move from the Southern Plains
Wednesday to northern Quebec by Friday morning. Wintry
precipitation is forecast for western Lake Superior and wind
speeds will increase. Small Craft Advisories may eventually be
needed and gale-force gusts are not out of the question Thursday
afternoon through Friday.
.PRELIMINARY POINT TEMPS/POPS...
DLH 29 36 29 36 / 60 30 10 50
INL 30 36 28 33 / 70 50 10 40
BRD 33 39 29 37 / 70 10 10 50
HYR 29 38 28 39 / 50 30 10 30
ASX 28 38 30 40 / 30 30 10 30
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
725 PM EST Mon Nov 18 2019
Very stagnant weather pattern over Southeast Michigan with surface
col in place down into portions of the Central Great Lakes with
little to no gradient locally. Largely clear skies over Southeast
Michigan now with IFR and LIFR conditions over western Lower
Michigan. Plan view of theta e is actually of no real use, with
cloud across the western state largely lined out to minimum in 850mb
temperatures. This axis of colder low-mid temperatures will slowly
leak eastward into Southeast Michigan tonight. No observed drizzle
or light rain showers nearby. There is uncertainty with the forecast
tonight although much of the uncertainty is a result of a very
questionable NAM moisture profile in the boundary layer. The most
likely scenario will be some lighter br/hz development with the clear
skies, then low stratus and marginally compromised visibility late
tonight. The RAP solutions suggests the only legit possibility is
some shallow ground fog by daybreak. Given the RAP solution and no
boundary warm advection/shear whatsoever, no drizzle, freezing
drizzle anticipated. High confidence in high MVFR/low VFR for
Tuesday across all the terminals.
DTW...No freezing precipitation expected.
DTW THRESHOLD PROBABILITIES...
* High for ceiling 5000 ft or less late tonight and Tuesday.
Issued at 304 PM EST Mon Nov 18 2019
A good deal of sunshine along/south of I-69 has pushed temperatures
to normal values (well into the 40s/near 50 degrees) this
afternoon, the warmest day in over a week.
Longwave upper level trough east of the Mississippi River Valley,
with trailing upper level energy/shearing out PV axis over the
Western Great Lakes/Western Ohio Valley gradually tracking through
the Central Great Lakes tonight through Tuesday night. Somewhat
moist low levels (especially with snow melt) and weak low level
convergence may be enough to generate a little drizzle/fog. There may
be enough breaks in the clouds around this evening for temps to make
a quick run to at/slightly below freezing, and with the lack of ice
nuclei/dry mid levels overnight will include a patchy light freezing
drizzle mention to go with the patchy light drizzle/fog. But
confidence is low there will be any appreciable precipitation (pops
<20). Low clouds expected to persist through the day tomorrow,
limiting diurnal response to around 10 degrees (around 40/lower 40s).
Upper level energy/low off the Baja California coast on Tuesday will
be booted off to the northeast as upper level trough digs south
along the West Coast.
Good clustering of GFS ensembles with the low pressure track through
eastern Iowa Thursday morning and through Central Lake Michigan
in the afternoon, placing southeast Michigan on warm side as 850 MB
temps push to 6 C. With the widespread rain and dew pts pushing into
40s, whatever is left of the snow pack should be dissipated.
Locations close to the low track (Tri-Cities region) and where the
gradient relaxes enough, could potentially have a period of moist
advection fog coming over cold ground/left over snow cover.
Progressive cold pool/shortwave trough tracking through the Central
Great Lakes Thursday night/Friday morning, with 925 MB temps
bottoming out around -3 C (per 12z Euro) likely holding maxes in the
upper 30s to around 40 degrees on Friday.
Will then be watching the southern system coming out of Texas, as
the 00/12z Euro is sort of out on its on bringing the deformation
associated with this system this far north. Outgoing forecast will
follow majority of the solutions, low chance/mainly a miss to
southeast Michigan. 12z Canadian/ICON/GFS ensembles have greater
separation between the northern/southern streams (stronger northwest
confluent flow behind Friday`s trough), and thus track the system
harmlessly through southeast U.S.
Favorable marine conditions through the early week period as a weak
surface trough becomes established over the central Great Lakes.
Building high pressure then ensures quiet conditions continue
through Wednesday. Deepening low pressure will then lift along the
climatological track from the Mississippi Valley to the Straits on
Thursday. Moderate SSE to S wind will develop in advance of this
system early Thursday then veer to northwesterly behind the
associated cold front overnight Thursday. Northwesterly gusts to
near-gales are forecast for the bulk of Friday. While gale headlines
are not expected at this time, gusty winds and elevated waves will
eventually warrant small craft advisories for Friday.
Low pressure tracking through the western Great Lakes on Thursday
will bring widespread rain to southeast Michigan during the day,
with total rainfall amounts generally around half an inch. With the
snow pack continuing to dwindle/slowly released over the next
couple of days, no flooding is anticipated, but standing water in
low lying areas can be expected.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Green Bay WI
550 PM CST Mon Nov 18 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Tuesday
Issued at 241 PM CST Mon Nov 18 2019
The latest RAP analysis and satellite/radar imagery show a weak
surface ridge axis moving across the western half of Wisconsin
early this afternoon. Widespread low overcast remains in place
across the region and the clearing line over Minnesota has made
little progress eastward so far today. Visibilities in mist and
drizzle have gradually improved through midday, and road
conditions have improved as well. Looking to the west, weak
shortwave energy is moving to the southeast over the eastern
Dakotas with mainly light right and temps in the 40s and 50s. As
this shortwave tracks towards the region late tonight into
Tuesday, forecast concerns mainly revolve around potential and
timing of light wintry weather.
Tonight...Weak high pressure will shift east of the region, while
a warm front and shortwave energy approach from the west. With a
stout inversion, overcast skies have little potential of
clearing. Meanwhile, the shortwave and associated warm front have
slowed down somewhat, and will approach central WI in the 3 to 6
am time period. Guidance generally keeps the heaviest precip over
western WI, but it appears that light snow will clip western
Marathon, Wood, Portage, and Waushara counties where up to a half
inch of snow could fall by 6 am. Otherwise, clouds should limit
the nocturnal fall of temperatures, so trended heavily towards
last nights lows for lows tonight.
Tuesday...Shortwave energy will continue to slide southeast across
the region. Light snow will likely be diminishing in the morning
over parts of central WI, where there may be an additional tenth
or two of accumulations. Although most models have precip
weakening by late morning, forecast soundings remain relatively
saturated through the rest of the day from the Fox Valley to
north-central WI. So wonder if the area will see occasional
freezing drizzle/drizzle/flurries once the more widespread precip
ends in the morning. With little change to the low overcast,
temps shouldnt warm much, and stayed with highs in the middle to
.LONG TERM...Tuesday Night Through Monday
Issued at 241 PM CST Mon Nov 18 2019
Mostly cloudy skies and generally dry conditions are anticipated
as a weak ridge of high pressure moves through Tuesday night into
A strong low pressure system is expected to arrive Wednesday
night into Thursday, and the GFS/ECMWF are in decent agreement on
timing and a track through southeast/east central Wisconsin. Low-
level thermal profiles and thicknesses suggest rain across all but
the far northwest part of GRB CWA by early Thursday, where
pockets of snow or freezing rain may mix in. The rain/snow line is
expected to gradually shift southeast across north central WI
during the day, but the heavier precipitation should be tapering
off as this occurs. Could see 1 to 3 inches of accumulation in our
northwest counties before the system pulls out Thursday
afternoon. Farther southeast, a good slug of moisture, with PWATs
exceeding 1 inch, will lead to moderate rainfall late Wednesday
night into Thursday morning, with rainfall totals likely reaching
a half inch to an inch. With frost depths of 4+ inches over the
forecast area, runoff from the rain could cause minor flooding
As the low pressure system exits, there will be potential for a
brief period of light lake effect snow showers over north central
WI Thursday night.
The weekend looks quiet, with systems tracking north and south of
the forecast area. Looks like a generally dry weekend, with
temperatures near seasonal normals.
.AVIATION...for 00Z TAF Issuance
Issued at 550 PM CST Mon Nov 18 2019
The solid deck of IFR/MVFR CIGS will continue into Tuesday, with
VSBYs possibly falling from VFR to MVFR this evening. Fog should
not get much worse due to the thick stratus deck in place. CIGS
might lower slightly overnight into Tuesday as a weak weather
system pushes south/west of the area. Some light snow is possible
at KAUW/KCWA/KRHI, reducing VSBYs for a time, but little to no
accumulation is expected. Some flurries, sprinkles, or drizzle is
possible Tuesday afternoon across the entire area, but confidence
not high enough to include in the TAFs and not expecting any
impacts. Winds will remain very light through the TAF period.
Area Forecast Discussion
National Weather Service Louisville KY
932 PM EST Mon Nov 18 2019
Issued at 932 PM EST Mon Nov 18 2019
A quiet, cool, cloudy night is in store. Went ahead and added in
some light rain during the pre-dawn hours west through south of
Bowling Green as the HRRR and NAM3km show patch of light rain
between Saint Louis and Paducah sliding southeastward into middle
.Short Term...(This evening through Wednesday)
Issued at 230 PM EST Mon Nov 18 2019
One upper wave is crossing into the I-75 corridor at this time. Our
next light rain producer is crossing into North Dakota this hour.
Vortmax associated with this system will be more elongated northwest
to southeast. There will be just a smidge more moisture for this
system to work with Tuesday morning as it moves into our region, so
we will call for a better chance for measurable rains. Confidence in
placement of the swath of rain is a little lower than expected with
this near-term of a system, as forecast rain swaths still range from
just west of our region to just northeast of it. The median solution
would peg a band in our area, so will call for 30-40 PoPs along an
axis from Madison, IN to Lexington, KY. Timing is a little later in
the morning than what we had today. Even if it were
earlier...colder...any precip likely would not cause impacts thanks
to warm road temperatures.
Once that system heads east of the region Tuesday night, we`ll get
high pressure over us at the surface for Wednesday morning along
with building heights aloft. This ridging will warm us up and allow
high temperatures to be normal for once in this month that has seen
many colder than normal days. The only other aspect to add for
Wednesday may be for fog potential in the morning. With high
pressure right over us and some light rains during the day, we could
see some river valley fog formation. Will introduce that with this
.Long Term...(Wednesday night through Monday)
Issued at 239 PM EST Mon Nov 18 2019
After dry weather Wednesday night, rain chances will increase
significantly for the latter part of the work week. Isentropic
upglide will increase Thursday through Friday as an upper trough
advances from the Rockies into the Great Plains and a 5H jet
develops from the southern Plains to the Great Lakes. A surface low
will proceed from the Midwest Thursday through the Great Lakes to
Quebec by Friday, pulling a trailing cold front through the Ohio
Valley Thursday night-Friday. Temperatures support rain as the
precipitation type, with less than an inch expected.
Friday night through the first half of the weekend another surface
low may develop further southwest along the boundary ahead of an
incoming upper trough axis, causing PoPs to linger in the forecast
through Saturday evening. This would mostly be light rain, but some
precipitation type issues may arise as temperatures bottom out
around the freezing mark Saturday morning in southern Indiana.
.Aviation...(00Z TAF Issuance)
Issued at 620 PM EST Mon Nov 18 2019
The wave that brought us clouds and sprinkles today will pull off to
the east this evening and take its low clouds along with it.
However, the next wave will slide in from the northwest and bring a
new batch of low clouds and light rain to the region Tuesday morning
and afternoon. SDF and LEX stand the best shot at seeing rain. A
surface boundary will shift light winds from south to west on
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
908 PM CST Mon Nov 18 2019
Issued at 838 PM CST Mon Nov 18 2019
Have made some changes to increase PoPs...mainly this evening
across much of central and northeast Missouri. The RAP is showing
850mb warm advection over central and eastern Missouri in excess
of 15C/hr in some spots which is likely what`s producing the
enhanced bands of rain we`re currently seeing on radar. There`ve
even been a few lightning flashes over western Missouri over the
past couple of hours. The RAP has a small area of 30-90 J/Kg
MUCAPE that clips our central Missouri counties over the next
couple of hours, but I think I`ll keep thunder out of the forecast
for now. The strong warm advection diminishes after midnight as
the low level circulation moves east of the Mississippi River and
the shortwave now digging into Missouri continues on its way
southeast into Kentucky and Tennessee.
.SHORT TERM... (Through Late Tuesday Night)
Issued at 315 PM CST Mon Nov 18 2019
Much of the period will be quiet in relative terms with little
concern for impactful weather. The initial issue will be
addressing the weak system sliding northwest to southeast through
the area this evening.
So far, the result has been an increase in mid to high clouds
with overcast skies through the region. Much of the day has only
resulted in isolated to scattered shower activity along a narrow
corridor of mid-level lift that stretched through central Missouri.
Showers may become a bit more numerous (not widespread) late this
evening and overnight as an area of better lift drift southeast
out of Iowa. Expect this to be a quick pass with light rain moving
along and east of the Mississippi River into Tuesday. All
precipitation should progress into Illinois and east of the CWA
Dry conditions are anticipated through the remainder of Tuesday as
ridging builds in from the west. Southerly winds will also give a
slight boost to temperatures, which will trend warmer from east to
west. Expect highs Tuesday to range from near 50 in interior
section of Illinois to the upper 50s over central and southeast
.LONG TERM... (Wednesday through Next Monday)
Issued at 315 PM CST Mon Nov 18 2019
The primary message in the long term relates to much milder
weather through the midweek stretch, along with a more active
pattern that sets up over the region.
An upper ridge begins to build east over strengthening surface
high pressure that will center over the Ohio Valley through
Wednesday. Southerly flow will couple with dry conditions to push
temperatures well into the 50s over much of the area with lower
60s being favored through central Missouri.
The next system will come into focus late Wednesday into Thursday.
Guidance remains is good agreement in placement of a surface low
tracking northeast through the plains and into the Upper
Mississippi Valley. Deep southerly flow will pump moisture
northward out of the gulf and send PWATs above one inch. A cold
front extending south of the system will be the primary source for
rain chances Wednesday night into Thursday morning, as the bulk of
lift remain north in relation to the closed upper low. So, while
categorical chances are in the forecast, any widespread, long
duration precipitation is likely to affect locations north of the
There is the potential that temperatures on Thursday will be even
milder than Wednesday. However, it will likely be reliant on the
timing of the late Wednesday/Thursday morning rainfall and
trailing cold front. Temperatures ahead of the front may climb
well into the 60s with ensemble member approach 70 degrees in many
instance. Current forecasts for low to mid-60s just east of
Columbia, running east along and south of I-70. Colder air will
begin to work in behind the front through the day, ultimately
sending temperatures down through the afternoon.
Guidance diverges greatly beyond Thursday. The general theme is
for colder air to return as the boundary stalls to the south. This
will become the focus for an additional system to track out of the
southwest later in the week. This could be key in introducing
moisture over a colder surface to bring wintry weather back into
the picture later Friday into Saturday. Confidence is very low,
though, given the spread in guidance and timing issue.
The remainder of the period looks drier beyond the weekend with
temperatures near to slightly above normal into early next week.
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 526 PM CST Mon Nov 18 2019
Low pressure over Iowa and Minnesota will slide south-southeast
tonight into the mid Mississippi Valley. Light rain and sprinkles
will accompany the low, along with lowering clouds. Although most
of the area is expected to remain VFR with this light
precipitation and the lowering cloud deck, it looks likely that
parts of northeast Missouri and west central Illinois will see
MVFR ceilings between 1500-2800 feet between 07Z-15Z. Some models
are even showing IFR ceilings in this area, though confidence is
not yet high enough to mention in the KUIN TAF. Expect wind to
increase from the northwest as the low continues moving east-
southeast on Tuesday with gusts up to around 20kts.
SPECIFICS FOR KSTL:
VFR flight conditions with occasional sprinkles are expected at
Lambert this evening. There may be more light rain or sprinkles
overnight, but little or no impact to flight conditions is
expected at this time. Wind is expected to increase to between
10-15kts Tuesday morning with gusts to around 20-25ks, diminishing
in the afternoon with continuing VFR flight conditions.
Area Forecast Discussion
National Weather Service Miami FL
654 PM EST Mon Nov 18 2019
VFR conditions will prevail throughout the forecast period. Light
and variable winds across all terminals overnight will increase
out of the west northwest to near 10 knots by late Tuesday
morning. These winds will then once again diminish on Tuesday
No changes needed to be made to the forecast as everything looks
on track. A reinforcing cold front will move through the region by
Tuesday morning. This front will not have enough moisture to work
with, so it will move through dry. High pressure will build into
the region behind the front during the rest of the day on Tuesday
allowing for the dry conditions to continue. High temperatures on
Tuesday will range from the mid 70s across the northwestern
interior to around 80 across the east coast metro areas.
.Prev Discussion... /issued Issued by National Weather Service Jacksonville FL/
Short Term (Through Tuesday night)...
Low clouds finally lifted out this afternoon as a storm system
along eastern seaboard continues to move Ne. Jet streak just
north of the area will continue to bring in occasional mid and
high clouds. A cold front will sweep through the area Tuesday
morning bringing in a period of cloudiness in the morning
followed by clearing in the afternoon. The front may produce
a few showers along the coast otherwise a mainly dry frontal
passage expected. A cool area of high pressure builds into the
area Tuesday night in the wake of the front bringing in cooler
and drier conditions.
Long Term (Wednesday through Monday)...
High pressure then builds across the area behind the boundary
late Wednesday and slides further into the Western Atlantic by the
end of the week. This will aid in veering winds out of the
northeast then east. The addition of an easterly component to the
flow will modify the airmass and induce a gradual warming trend
back above 80 during the day. With amplified ridging aloft, South
Florida should remain dry into the first half of the weekend.
Thereafter, global models depict cyclogenesis over the Central
CONUS quickly departing northeastward as a result of a progressive
and amplifying upper level trough. There is fairly good agreement
on the 12Z runs of the GFS and ECMWF on a frontal passage across
south Fl Sunday morning. Most of the deep moisture lifts north
of the area although the front may bring isolated to scattered
showers (best rain chances gulf coast) Sunday morning. Clearing
with cooler and drier conditions late Sunday into early next week.
SCA remains in effect through tonight. Large Ne swells
will produce combined seas of 7 to 10 feet into tonight. The
northeast swells will decrease on Tuesday with combined seas of 4
to 6 feet expected by Tuesday afternoon.
A High Surf Advisory remains in effect for possible breakers of 7
to 8 feet over the beaches of Palm Beach County, along with
a High Risk of Rip currents. Minor coastal flooding is possible
during high tide along Palm Beach...Broward...and Miami-Dade
counties into early Tuesday morning.
Prev Discussion... /issued Issued by National Weather Service
Jacksonville FL /
Prevailing VFR cigs have developed this afternoon with scattered
decks around 1500-3000 ft into this evening. Mainly VFR tonight but
model guidance from HRRR and NAM hinting of possible low clouds late
tonight through Tuesday morning that may be just above MVFR cigs.
For now, used mainly just scattered cigs 3500-4000 ft due to the
uncertainty. Winds will be west to northwest of around 10 kt,
becoming light and variable tonight and west to northwest again on
Tuesday aob 10 kt.
.Preliminary Point Temps/PoPs...
West Palm Beach 60 77 57 73 / 0 0 0 0
Fort Lauderdale 63 78 60 75 / 0 0 0 0
Miami 63 80 59 76 / 0 0 0 0
Naples 63 77 58 75 / 10 10 0 0
FL...High Rip Current Risk through Tuesday evening for FLZ168-172-173.
High Surf Advisory until 7 AM EST Tuesday for FLZ168.
Coastal Flood Advisory until 7 AM EST Tuesday for FLZ168.
AM...Small Craft Advisory until 7 AM EST Tuesday for AMZ650-651-670-
Area Forecast Discussion
National Weather Service Marquette MI
534 PM EST Mon Nov 18 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 358 PM EST MON NOV 18 2019
WV imagery and RAP analysis indicated a mid/upper level
troughing from northern Manitoba through the central Great Lakes to
a low over OH/WV. A weak shortwave was slowly into central Upper
Michigan but supported little more than patchy drizzle or light
rain. Another weak shrtwv over ne MN also was not strong enough to
bring any pcpn. At the surface, a weak trough lingered into eastern
Upper Michigan. Otherwise, a very weak pressure gradient prevailed
with light winds across the area.
Tonight into Tuesday, Expect continued light rain/drizzle chances
over the east as the shrtwv moves through the area. When temps drop
slightly some fzdz may also be possible as ice nuclei will be scarce
in the shallow moist layer. However, any icing chances will be
As the weakening shortwave trough axis from the Dakotas approaches
late, some light mixed precipitation is possible mainly over the far
western cwa, most likely in the form or light snow and patchy fzdz
that will linger into Tue morning. Some weak upslope southerly flow
into the far eastern cwa off of Lake Michigan could also support
With persistent clouds, temps are not expected to drop off very far
with min readings in the upper 20s to around 30, closer to the
higher end of guidance. Highs will rebound back into the upper 30s
Tuesday with continued light winds and cloudy skies.
.LONG TERM...(Tuesday night through Monday)
Issued at 300 PM EST MON NOV 18 2019
Well, if you were hoping for a widespread heavy snow event Thursday,
you`ll probably have to wait a while longer. The far western UP
should still get some accumulating snow with the incoming system,
but models have trended further west with the track of the low and a
tad warmer with temperatures, meaning the majority of the CWA is now
in line for mostly rain. More details to come...
Tuesday night, high-resolution models indicate the possibility of
some mixed precipitation over the west and along the Lake Superior
shore east of Marquette. Any precipitation would be very widely
scattered and light and end well before sunrise, and the best chance
for any QPF >= 0.01" would be where weak orographic support may help
in the higher terrain of the Porkies and the southern Keweenaw.
These will also be locations at higher risk of T<=32F, so could be a
couple spots with a very light glaze of ice overnight.
High pressure building into the Ohio Valley Wednesday will extend
ridging far enough north that the daytime will remain dry. Some
shortwave-induced precipitation will approach from the west late in
the day ahead of the main sfc low pushing NE through the Plains, and
some of this may impact western Upper Michigan through the evening
and early overnight but will mainly remain over the western lake.
While differences remain in the strength of the low center, there is
agreement in the track going from central IA 12Z Thur to near the
Soo 00Z Fri to SW Quebec 12Z Fri. Sfc low will deepen over this
time frame as mid-level troughing moves in from the NW. The initial
surge of precipitation will arrive sometime later overnight
Wednesday and continue to fill in Thursday morning. Colder air may
lag enough behind the system to prevent much in the way of lake
enhancement processes, but nonetheless anomalously high moisture
content has led to qpf forecasts of 0.5-1" and some isolated higher
amounts wouldn`t be out of the question. Current model consensus
gives moderately high confidence that most locations east of a line
from IMT to MQT will see primarily rain with better snow chances
along the western border of Upper Michigan. At 10:1 SLRs, GEFS mean
calls for 1-5 inches of snow west with better chances for the higher
end closer to the WI border. Official forecast at this time does not
account for this N/S gradient and currently calls for a widespread 3-
5+" in the higher terrain. Even there, however, there could be
additional changes in the forecast track that allow for further
refinement to snow totals if the more westward/warmer trends
Another wrench to throw into this forecast is that both the default
NBM solution as well as the 12Z NAM indicate the chance for a period
of freezing rain over portions of the west half. A relatively
significant warm nose is likely, but there are doubts about sfc
temperatures being cold enough to freeze up. Have opted to
significantly decrease and downplay this potential by increasing
temperatures 2 degrees across the board 00Z Thur to 00z Fri. This
had the added effect of cutting down on NBM snow totals which were
somewhat inflated by old, colder model data. Given the warmer temps
in the area the last several days, the risk of road surfaces
remaining significantly below freezing on Thursday is low.
As the low begins to exit and colder air works in behind it, most
locations even over the east should still see a brief changeover to
snow before the synoptic forcing exits. Then, some NW wind LES will
build for a time Thursday night into Friday morning, but this will
be short lived with 850 mb temperatures bottoming out over a short
period and then quickly increasing Friday into Saturday. The GFS
remains an outlier with holding onto the colder air into Friday
night but ensemble means suggest a quicker warm up so POPs are cut
off after 18Z Fri. LES accumulations are not currently expected to
be too significant but will monitor for the potential of
concentrated banding to set up, if only for a short time.
After colder temps on Friday, we`ll return to more seasonal, mild
highs in the 30s over the weekend. Should be mostly dry but slight
precip chances will return into Monday. The ECMWF has introduced a
shortwave digging out of Manitoba Monday that is not resolved in
other models. Better chances for a colder airmass to push back in
towards Tuesday that may allow for more LES, but that`s beyond the
scope of this forecast.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 533 PM EST MON NOV 18 2019
With abundant low level moisture over the region as a trough moves
through, expect mainly MVFR conditions to prevail through the period
at all terminals.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 358 PM EST MON NOV 18 2019
Winds will remain fairly light (less than 15 knots) through
Wednesday night as a trough hangs over the area followed by a brief
ridge. Models then indicate a low pressure system will develop
across the Central Plains and lift northeast toward Lake Huron
Thursday evening and then into Quebec on Friday. This will bring the
next chance at north to northwest winds approaching 30 knots, and
possibly exceeding 30 knots over the eastern lake by Thursday
evening. Winds will then quickly subside below 20 knots Friday