Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/23/19
Area Forecast Discussion
National Weather Service Bismarck ND
946 PM CDT Tue Oct 22 2019
.UPDATE...
Issued at 930 PM CDT Tue Oct 22 2019
Update to the previous discussion about western North Dakota
snow tonight: While there is an impressive burst of forcing
displayed via recent RAP guidance (strong frontogenesis from 925mb
through 600mb under divergence aloft and omega within the
dendritic growth zone on forecast soundings), these forcings are
short lived and are maximized within a very thin band stretching from
southern McKenzie, through Stark, and into Sioux
county...occurring in just a few hours between the 05Z-12Z time
frame. Additionally surface temperatures within that potential
zone are still currently quite warm with Dickinson and Watford
City currently at 41 degrees. Thus the confidence that a band of
heavy snow can persist and accumulate long enough to reach Winter
Weather Advisory criteria (3-5 inches within 12 hours) is low.
That said, there is a decent chance some spots within this area
will see will see at least 3 inches overnight, it`s just that the
spatial extent of this potential is very uncertain still.
Obviously this will need continuous monitoring as short- term
trends develop.
The last update was to remove mention of thunder in the far
southwest. Thunderstorms associated with the surface low have
passed just to the south of Bowman county and additional
thunderstorms are not expected.
UPDATE Issued at 714 PM CDT Tue Oct 22 2019
This evening, a potent midlevel circulation was evident on water
vapor imagery centered over central Montana. Modest warm air
advection within the warm conveyor belt region was responsible for
light rain in our far southwest counties this evening. Further
west, a line of showers and scattered thunderstorms stretched over
eastern Montana along the cold front associated with the
aforementioned low. Steep low level lapse rates in southern
Montana were responsible for efficient momentum transfer and 40-60
mph wind gusts. While RAP guidance keeps the steeper low level
lapse rates (and thus a more favorable strong wind gust
environment) in South Dakota and Wyoming, there is still a
possibility for strong wind gusts accompanying
showers/thunderstorms in the southwest counties in the next couple
hours with current storm motions at around 50 mph.
In the overnight hours, the midlevel low is forecast to move over
a tightening baroclinic zone stretching from around McKenzie
county through Sioux county. A quick burst of snow along this line
of frontogenesis overnight should be enough to produce around 1
to 2 inches of accumulation overnight. Recent RAP runs have been a
little more aggressive with QPF along a very narrow portion of
this band, which may signal locally higher amounts may be possible
where the greatest forcing of this band sets up. While no major
changes were made to the forecast now, this will need to be
watched as high-resolution guidance continues to flow in.
&&
.SHORT TERM...
Clear skies prevail across much of western North Dakota this
afternoon with clouds gradually building in from the southwest late
this afternoon. A rather fast moving H5 shortwave will traverse the
western portions of the CWA tonight, with showers, mixed rain/snow
and even a chance of an isolated thunderstorm. The best chances for
measurable precipitation will occur mainly along and southwest of a
line from Grenora to Linton. Upper limits of precipitation
accumulation will generally be in the 0.25 to 0.50 inch range. Where
we see a transition to snow, accumulations of up to 2 inches are
possible, with the highest accumulations forecast generally along a
corridor that runs from Watford City to Elgin. Although not
widespread, areas where we see stronger convective activity could
see higher snowfall totals up to 3 inches. The Bismarck area is
expected to remain on the eastern side of the system, with lighter
snowfall totals of less than one inch.
Heading into Wednesday morning, light snow will change back over to
rain and persist into the early afternoon. Look for high
temperatures in the 30s to lower 40s. Low temperatures will fall
into the middle to upper 20s Wednesday night into Thursday morning.
.LONG TERM...
We will see a bit of a reprieve in precipitation On Thursday and
Friday before our next system moves into the region. Westerly flow
will allow high temperatures to climb into the 40s for Thursday and
into the 50s to near 60 degrees on Friday. A strong H5 low will move
across southern Alberta and into Manitoba Heading into Saturday
morning. This will facilitate another shortwave passage with an
associated cold front that will dive southeastward out of Canada. We
will likely reach our high temperatures early Saturday, with middle
40s along the International Border to upper 50s in south-central
North Dakota along the South Dakota border. Precipitation is
possible with the frontal passage; however, with rather dry
antecedent conditions and overall lack of available moisture, our
precipitation amounts will be quite low.
Temperatures will fall dramatically following the front, with highs
in the upper 20s to lower 30s Sunday through Tuesday. Lows during
this time will be in the teens and 20s. The 850 mb temps for the
Sunday through Tuesday period will range from -10C to -14C, focused
especially on Sunday morning. A secondary push of cold air follows
the first, with 850 mb temps as cold as -16C per the current
guidance.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 714 PM CDT Tue Oct 22 2019
MVFR, transitioning to IFR, cigs possible for KDIK beginning at
05Z with rain transitioning to snow. Reduced visibilities will
accompany the transition to snow overnight as well. Light snow
possible at KISN and KBIS at 05Z-12Z, though less likely.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AE
SHORT TERM...TLynch-FGF
LONG TERM....TLynch-FGF
AVIATION...AE
Area Forecast Discussion
National Weather Service Quad Cities IA IL
1042 PM CDT Tue Oct 22 2019
...HYDROLOGY UPDATE...
.SYNOPSIS...
Issued at 230 PM CDT Tue Oct 22 2019
Dreary, windy and cool: those are the words I would use to describe
how much of this day has felt so far. Thankfully, much nicer
weather was not too far away! As of 2 PM, temperatures across the
region ranged from 44 in Dubuque, to 57 in Macomb and Keokuk.
Clouds were breaking and sunshine was out in full force across
central and southeast Iowa. Unfortunately, it was still windy as
we remain under the last bits of control of a strong, 988 hPa
surface low pressure centered just east of the arrowhead of
Minnesota. High pressure was not too far to the southwest, and it
will just be enough to influence the first portion of the short
term period.
&&
.SHORT TERM...(This Evening through Wednesday Night)
ISSUED AT 230 PM CDT Tue Oct 22 2019
Key Messages...
1) Windy conditions subsiding this evening and tonight.
2) Slight chance of rain showers north of I-80 Wednesday morning
and afternoon.
Winds should continue to subside as we head through the evening, as
the low pressure loses its grip and the high pressure briefly takes
over. Surface ridging evident on latest mesoanalysis will build over
the area and will keep our weather dry & quiet through tonight. CAA
will continue and we should see our temperatures drop to values
cooler than previous nights. Currently advertise overnight lows
ranging from the low 30s along/north of Highway 20, to mid/upper 30s
south.
Clouds will begin to build back over the area early Wednesday, and
will limit afternoon highs to the low 50s along the Highway 20
corridor, to the the low 60s south of Highway 34. These clouds are
associated with a clipper that will pass across the area Wednesday
evening. Overall, guidance is not too impressive with this system,
and is quite variable on placement of precip as well. The NAMnest
and ARW support rain showers across the entire area, while the HRRR
and NMM show more of a banded nature to the precipitation, with a
focus more along and north of the Highway 20 corridor. I`m more
inclined to follow the later, as global guidance advertises the best
forcing and CVA with the shortwave aloft more into northeast Iowa
and southwest Wisconsin. However, I will mention slight POPs down to
the I-80 corridor as some of the guidance is supporting potential
for drizzle due to extra lift from isentropic upglide around 925-850
hPa. Any precip that falls will be negligible at best, with the
highest amounts expected to only be a few hundreths.
High pressure will quickly, and briefly, build back across the area
Wednesday night. Another system will begin to take shape over
eastern Oklahoma, southwest Missouri and northwest Arkansas, and
will be more of an influence in the long term period.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 230 PM CDT Tue Oct 22 2019
Key Messages...
1) Chance of rain showers over our far southeast CWA Thursday.
2) Generally dry and quiet through the weekend, slight chance of
rain Sunday.
3) Temperatures trending colder for next week.
System developing over the lower Mississippi Valley Wednesday night
will graze our southern CWA Thursday afternoon and evening. This
seems to be more hinted by the American models, while the CMC and
ECMWF are less aggressive on any system impact to our area.
Overall, quiet and dry conditions are primarily expected for the
area Thursday through Saturday as broad high pressure moves
overhead. Temperatures will return to near normal as southerly
return flow helps afternoon highs jump into the 50s/near 60.
Next chance of rain may be Saturday night and Sunday as guidance
shows a shortwave quickly ejecting out of the lower Rockies into
the Mississippi River Valley. The CMC and ECMWF advertise impacts
to our area and have remained fairly consistent. Meanwhile, the
12z GFS advertises no system with high pressure firmly in place
and the system much further east (towards the Mid Atlantic
states). For now, will maintain slight chance to chance of POPs
across the area. If precipitation were to fall, temperatures would
favor rain as the type. Another system may impact the area Monday
night and Tuesday, but this is only being driven by the ECMWF
thus far, so expect further adjustments.
Behind this system, a strong, deep trough is progged by all long
range guidance to build south from Alberta and Saskatchewan into the
Rockies. This will move east and usher cold temperatures
(agreement of 850 hPa temperatures around -10 C Wednesday morning)
into the eastern Great Plains and Midwest by mid to late next
week, just in time for Halloween (ghost costume in a comforter
perhaps?). While this is a bit far out, some raw guidance is
hinting at afternoon highs on some days in the upper 30s to low
40s for the period, with blended guidance not too far behind.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 619 PM CDT Tue Oct 22 2019
Gusty west winds will diminish to around 10 kts early this
evening at all sites with clear skies and VFR conditions through
the rest of the night. A fast moving low pressure system will
return cloud cover Wednesday and bring a round of light showers or
sprinkles. These are most likely to impact the CID and DBQ
terminals, where PROB30 groups were used. With limited moisture,
cloud bases are expected to remain high enough to keep conditions
VFR through the day.
&&
.HYDROLOGY...
Issued at 1041 PM CDT Tue Oct 22 2019
This evening`s forecast no longer has the Dubuque Railroad Bridge
gage exceeding flood stage within the next week. This is now in
line with previous day`s forecasts keeping the river below flood
stage. With only light rainfall expected over the next several
days upstream, this forecast is likely to change little and thus
the flood watch has been cancelled.
Otherwise, forecasts remain on track with most sites on the
Mississippi continuing to slowly fall, then becoming steady or
resuming a rising trend toward the end of the month as flow from
recent heavy rainfall in WI and MN makes its way downstream. On
the Rock River, Joslin is still forecast to drop below flood stage
Saturday.
&&
.CLIMATE...
ISSUED AT 230 PM CDT Tue Oct 22 2019
Long range guidance shows a strong upper level trough building south
from Canada into the Great Plains and Midwest by mid next week. This
trough will usher in cold air across the area that is atypical of
what is normally seen for late October/early November. The Climate
Prediction Center maintains a high probability (60-70%) of below
normal temperatures for the period (Oct 29 - Nov 4).
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Speck
SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Sheets
HYDROLOGY...Sheets
CLIMATE...Speck
Area Forecast Discussion
National Weather Service Green Bay WI
1035 PM CDT Tue Oct 22 2019
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 254 PM CDT Tue Oct 22 2019
The latest RAP analysis and satellite/radar imagery show a strong
area of low pressure lifting north of Lake Superior early this
afternoon. Deep moisture within cyclonic flow continues to wrap
around the low, and provide periods of showers and drizzle. Winds
have been gusting up to about 35 mph at times, highest over
northeast WI and might increase slightly around mid-afternoon, but
should remain below wind advisory criteria of 45 mph. Looking
upstream, widespread low overcast extends west into Minnesota and
south into east-central Illinois. Forecast concerns revolve around
strong wind potential and light precip trends.
Tonight...Low pressure will continue to lift northeast over
northern Ontario. Deep cyclonic flow will continue, however, with
thermal troughing and a strengthening inversion supporting low
overcast to persist through much of the night. It`s possible
central WI and the downsloping areas of northeast WI could see
some holes in the clouds develop late. Forecast soundings remain
support of areas of light rain and drizzle persisting into the
evening as saturation folds over the top of the inversion. But as
the low moves away, should see light precip chances diminish and
lift north through the night. After peaking late this afternoon,
should see winds gradually diminish through the night as well.
Temps wont fall much due to cloud cover and the breezy conditions,
with lows falling into the middle 30s to near 40 by the Lake.
Wednesday...Though low pressure will continue to move farther away
from the region, the low overcast will be slow to lift north, and
may hang around northern WI through the afternoon. Meanwhile, any
clearing that occurs over central and east-central WI looks to be
short-lived as a shortwave trough will quickly move across the
northern Mississippi Valley and into the western Great Lakes in
the afternoon. It will bring a low chance of light rain into
parts of central and east-central WI, mainly in the late afternoon
hours. Highs ranging from the low 40s in the north to near 50 in
the east.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 254 PM CDT Tue Oct 22 2019
Cool and dry weather is expected Wednesday through
Saturday as northwest upper flow prevails across the Great Lakes.
Temperatures should range from 5 to 10 degrees below normal.
The medium range models have differences as far as Saturday night
and Sunday go. The GFS moves an upper trough across the Lower Ohio
Valley keeping Wisconsin dry, while the ECMWF and GEM have a
negatively tilted upper system lifting northeast across Illinois
which would bring a chilly rain to the area. The jet energy for
that system is still off the Pacific Coast so we do not have a lot
of confidence in any of the model forecasts yet.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1028 PM CDT Tue Oct 22 2019
The strong low pressure system will continue to lift northeast
away from the region through the TAF period. However, moist
cyclonic flow will continue, resulting periods of light rain and
drizzle across mainly north central WI into Wednesday morning.
The rain may briefly mix with snow at times. CIGs and VSBYs will
mainly be MVFR, but may briefly fall to IFR in north central WI
overnight. MVFR conditions should prevail on Wednesday, except in
eastern WI, where improvement to VFR is anticipated by late
morning.
Another system will pass by to our south Wednesday afternoon and
evening, and may bring some light showers to parts of central WI
and the Fox Valley.
&&
.MARINE...
Issued at 254 PM CDT Tue Oct 22 2019
After a lull this morning, southwest winds are
projected to increase again but remain under gale force late this
afternoon into this evening. If winds proceed as planned, think
the gale warning will likely get downgraded to a small craft
advisory on the Bay and possibly on the Lake too. Winds and waves
that are hazardous to small craft will then likely continue until
Wednesday afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......Kieckbusch
MARINE.........MPC
Area Forecast Discussion
National Weather Service Marquette MI
742 PM EDT Tue Oct 22 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 555 PM EDT TUE OCT 22 2019
WV imagery and RAP analysis indicated a deep trough over the central
CONUS with the mid/upper level low over Lake Superior. Weak
shortwaves along with abundant moisture continued rotate around the
low supporting area of sct showers that were moving through western
Lake Superior and western Upper Michigan. At the surface, a 987 mb
trough extended from nw of Thunder Bay Ontario to central Lake
Superior. The tighter pres gradient farther to the south supported
gales and high waves from Lake Michigan into portions of Delta and
Schoolcraft counties.
Tonight, expect sct/nmrs showers through this evening especially
over the west. As colder air moves in with 850 mb temps dropping to
near -5C with deep moisture over the area, westerly flow lake
effect/enhanced rain showers will also affect western portions of
Upper Michigan. Wet-bulb zero heights will drop off enough to allow
some snow to mix with the rain over the higher terrain.
Winds off of Lake Michigan will slowly diminish this evening
allowing waves to subside enough to alleviate any remaining
lakeshore flooding.
Wednesday, as the mid level and sfc low lift northeast toward James
Bay and weeken, expect the pcpn coverage and amouns to diminish.
However, the deeper moisture will remain across the area along with
cyclonic westerly low level winds. This will keep lake
effect/enhanced pcpn going for mainly northwest portions of Upper
Michigan. Highs will range from the lower 40s west to near 50 over
the south and east. Wet-bulb zero heights will continue to support a
mix of snow for the west with some minor accumulations on grassy
areas possible.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 403 PM EDT TUE OCT 22 2019
Long term period starts off with the persistent upper level low
thats been impacting our region since the wind/lakeshore flooding
event Monday. Beginning Wednesday night, the low will be over the
southern fringes of Hudson Bay and an associated shortwave will be
pulled over Lake Superior bringing the chance for some lake effect
rain/snow showers to the NW/W lake effect belts. Dry air will settle
in behind it and high pressure eventually settling in on Friday.
There is a weak shortwave signal Friday, but given the amount of dry
air that will need to be overcome, don`t expect much in the way of
precipitation. Following this shortwave`s exit, southwesterly flow
and subsidence will set in Friday afternoon through Saturday. Toward
the later part of the period beginning Sunday there is a chance for
another low pressure moving across the region, but at the moment
models are diverging on any kind of consensus.
Wednesday night through early Thursday, a shortwave associated with
our outgoing upper level low will move through the region. CAA will
settle 850 temps ~-6 to -8 C. With Lake Superior temps hovering near
+7C (delta ~13C), it should be unstable enough for some lake effect
rain showers to develop in the northwest/west lake effect belts.
Nothing impressive is expected due to low inversion heights near 5k
feet and some low level dry air in place ahead of the shortwave, so
any development will likely be light and scattered in nature.
Wetbulb zero heights look low enough to keep precip as snow away
from the shorelines in Gogebic and Ontonagon into the central
interior, and even the Michigamme Highlands if precip makes it that
far inland. Accumulations look high enough to cause perhaps a
dusting but given surface temperatures staying above freezing, its
likely everything will melt during the day Thursday. Warmer temps in
the Keweenaw Peninsula will likely make precip a mix and out east
and primarily rain.
Friday morning looks chilly, with 850 temps of -6 to -8C over the
region, expect lows to hover near freezing with the typical interior
cold spots seeing 20s and maybe some upper teens. A 2nd shortwave
moving through Friday will need to overcome some low level dry air
before any precip reaches the surface. Lower inversion heights will
also make any development harder to sustain. Temperatures will be
cold enough aloft for a potential mix of rain/snow in the Copper
Country, but with southwesterly flow setting in during the day,
surface warming into the low 40s will be enough to melt any
accumulations.
Increasing subsidence with a building high pressure will create a
couple of nice dry days beginning Friday afternoon. Saturday, with
increased mixing up to ~2k feet, some gusty winds will be possible
during the afternoon hours. Temperatures will climb into the low
50s.
Models begin to diverge from here, with the GFS bringing a low up
from the central/southern Plains toward the lower Great lakes and
east coast beginning early Friday while the ECMWF and Canadian have
this progression beginning Saturday and keeping the system much more
west, bringing the Upper Great Lakes the potential for another shot
of rain. Until the models reach more of a consensus on the placement
and timing of this low, I`m going to keep POPs low. Saturday night
into Sunday, another low will move across middle-Canada toward James
Bay. Given the uncertainty in the placement of the earlier low, its
hard to say if the flow through the shortwave will be enough to
develop any lake effect showers. Similarly, keeping POPs low. Behind
the low, cold temperatures move in. Right now highs for the early
half of the week look only to climb into the 30s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 742 PM EDT TUE OCT 22 2019
Low-level moisture and an area of low pressure over Lake Superior
will continue to bring transient -SHRA throughout the UP and all TAF
sites. Overnight, -SHRASN will become more lake-induced rather than
from the low pressure, so expecting SAW to become dry, with a chance
at VFR. As pockets of showers move through, latest obs show the
chance for vsbys to fall into IFR briefly, so have included a tempo
at IWD and CMX to account for this. Until this low continues further
north late tomorrow, expect gusty conditions across all TAF sites.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 555 PM EDT TUE OCT 22 2019
The low pressure system that created storm-force gusts yesterday has
moved north of Lake Superior this afternoon as the gradient relaxes.
WNW winds are expected to continue through tomorrow evening, gusting
up to 30 knots with a few gale-force gusts throughout the next 24
hours or so. Expect this low to slowly moving north, reaching James
Bay by Thursday. During this time, winds are expected to slow relax
to 20 knots from the NW by Friday morning. High pressure moving
through the Central Plains later this week will switch winds more
from the SW for this upcoming weekend with winds gusting up to 25
knots on Saturday and Sunday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Lakeshore Flood Advisory until 8 PM EDT this evening for MIZ013.
Lakeshore Flood Warning until midnight EDT tonight for MIZ014.
Lake Superior...
None.
Lake Michigan...
Gale Warning until 8 PM EDT this evening for LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JP
AVIATION...JAW
MARINE...JAW