Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/02/22
Area Forecast Discussion
National Weather Service Quad Cities IA IL
655 PM CDT Fri Apr 1 2022
...00Z AVIATION UPDATE...
Issued at 252 PM CDT Fri Apr 1 2022
Surface high pressure is in place along the Mississippi River this
afternoon while on water vapor tonight`s shortwave is evident moving
into central South Dakota and Nebraska. Diurnally driven cumulus has
developed across the area with temperatures generally in the lower
to mid 40s. Dewpoints ranged from mid 20s to lower 30s across the
.SHORT TERM...(This Evening through Saturday)
ISSUED AT 252 PM CDT Fri Apr 1 2022
1. A fast moving storm system will bring accumulating snow to part
of the area late tonight into Saturday morning.
2. A Winter Weather Advisory has been issues for Iowa Counties along
and north of Highway 30 plus Jo Davies County in Illinois. 2 to 4
inches of snow is possible in the advisory area with a slushy 1 to 2
inches of snow on area roadways.
The main forecast concern is precipitation type and timing. There
are slight differences between the models in the timing and
placement of this shortwave.
Models show the 500 mb ridge axis along the Mississippi River by 00
UTC this evening with a 500 MB trough spreading into central
Nebraska. The latest runs of the ECWMF and GFS continue to be about
50 to 100 miles east of the NAM and Canadian. The best accumulations
will be prior to sunrise. This is leading to slight timing
differences between the models. The ECWMF and GFS continue to time
the best lift across eastern Iowa in the 9 to 12 UTC timeframe while
the NAM and Canadian are about 3 hours hours slower. Additionally,
the HRRR and NAMNest show a secondary area of intense precipitation
across the I-80 corridor. Low temperatures across all but the
Highway 20 corridor will be in the mid 30s where lows will be in the
lower 30s. As the atmosphere saturates from the top down,
precipitation falling into the layer will result in the lower part
of the column dropping below freezing and precipitation changing
over to all snow, mainly along and north of Highway 30. This will
lead to accumulations of 2 to 4 inches. Rates overnight may approach
1 inch per hour during the peak. Expecting a mix to redevelop after
sunrise as the atmosphere slowly warms to do insolation. South of
Interstate 80, precipitation is expect to fall as all rain.
Precipitation will come to an end from west to east Saturday
As the cold front sweeps across the area Saturday expect northwest
winds of 10 to 25 MPH to develop behind the front and continue
through the rest of the day. High temperatures on Saturday will
range from the lower 40s in northwest Illinois to the mid 50s in far
.LONG TERM...(Saturday Night through Friday)
ISSUED AT 252 PM CDT Fri Apr 1 2022
1. Active pattern through the long term with series of clippers.
2. All precip looks to be rain.
Active flow regime expected through next week. Parade of clippers
will bring chances for precip and wind throughout. The first
clipper is expected to move in for Sunday. Into next week, a clipper
midweek is expected to move through the area as an closed upper
level low takes over for the rest of the work week, leading to
precipitation through that period.
Sunday, precipitation will encounter dry low levels. Rain will be
slow to overspread the area until the main wave approaches the area.
While there are chances for rain on Sunday afternoon, the bulk of
the precip should fall after 00z Monday and into the overnight.
Current rainfall forecast of a tenth to half an inch of rain is
expected. This will also help with our ongoing drought across the
Later in the week, a more complex momentum field is found across the
area as a wave followed by closed low is expected to affect the
region. This will likely lead to extended periods of cloud cover.
Rain looks likely with the front on Wednesday then again later
Thursday with the wrap around. Thermal fields suggest all rain with
this event midweek. That said, some mixing in of snow during the
night time is possible. Afternoon temps will melt any snow that
does fall at night. Depending on the guidance, this system could
also bring us half an inch to 1.5 inches of needed rain as well.
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
ISSUED AT 645 PM CDT Fri Apr 1 2022
VFR conditions will be seen through 06z-09z. Thereafter, conditions
will lower into MVFR with some IFR as a low pressure system
passes, accompanied by rain/snow primarily until 18z. Rain is
expected at BRL mostly for a few hour period. Rain is initially
expected at MLI, but then is likely to mix with or possibly even
change to a brief period of snow before ending. CID/DBQ will see
rain/snow initially changing to snow for several hours before
ending with some accumulation possible on elevated surfaces, and
will also be most favored for IFR conditions -- with even a low
chance of a brief period of LIFR at DBQ in heavier snow but too
low confidence to include. Low clouds in the wrap-around will
persist for much if not all of Saturday PM, with some clearing/
VFR developing late in the period at BRL and possibly CID/MLI.
S/SE winds generally around 10 kts or less will turn N/NW and gusty
at 10-20+ kts in the wake of the departing low.
IA...Winter Weather Advisory from 3 AM to 10 AM CDT Saturday for
IL...Winter Weather Advisory from 3 AM to 10 AM CDT Saturday for Jo
Area Forecast Discussion
National Weather Service Grand Forks ND
1030 PM CDT Fri Apr 1 2022
Issued at 941 PM CDT Fri Apr 1 2022
Showers are slowly making their way out of the area. FAR reported
rain at the last observation, so some is hitting the ground.
Temperatures are in the 30s and 40s currently across the area;
look for lows in the upper 20s and low 30s tonight.
UPDATE Issued at 633 PM CDT Fri Apr 1 2022
Showers are moving across the area this evening, no impacts are
expected. Mainly producing virga, however, some spots have seen
light rain. A clap or two of thunder cannot be ruled out, but no
lightning has occurred in the CWA as of writing this.
Tonight, winds should begin to shift to the west/northwest.
Forecast is on track.
.SHORT TERM...(This evening through Saturday night)
Issued at 301 PM CDT Fri Apr 1 2022
Precipitation chances and type tonight as well as temperatures
tomorrow will be the main challenges for the period.
Broad upper trough continues to rotate through the Plains States.
One embedded vorticity max has been rotating through central SD
and bringing some light precip to eastern portions of that state,
although so far everything as been staying south of our border.
Another, weaker vort max is entering western ND, and there has
been a fair amount of cumulus development to our west with daytime
heating. CAMs continue to show some showers pushing in across our
southeastern ND counties this evening, and doesn`t seem out of the
question with a few of the cu to our west starting to show some
returns on radar. Will continue to keep some chances for precip
mainly going south of the Hwy 2 corridor this evening. The NAM
and HRRR have some MU CAPE values around 250 J/kg in a narrow band
along the surface trough axis this evening as it enters
southeastern ND. Given current MU CAPE analysis from SPC, there is
already some weak instability out west and a clap or two of
thunder is not out of the question. Put in an isolated thunder
mention for a bit this evening, but should lose instability as we
go into the night and dropping temps could even bring a bit of
snow mixing in. Any amounts and impacts will be minimal.
Tomorrow should be fairly quiet and a bit cooler with weak high
pressure over the Plains and brief upper ridging between systems.
Highs should be mostly in the 40s, with some low 50s possible in
the west and upper 30s where there is snow cover in west central
MN. The next shortwave trough begins to approach Saturday night,
bringing increasing clouds and southeasterly winds.
.LONG TERM...(Sunday through Friday)
Issued at 301 PM CDT Fri Apr 1 2022
Main challenge for this forecast period is the potential for
precipitation on Sunday and again for Tuesday.
A vigorous upper level trof and attendant surface system will track
across the northern Plains on Sunday. General consensus is the best
chances for precipitation will be along the South Dakota border.
By Monday, the trof departs and the upper ridge amplifies. Return
surface flow and increased thicknesses will allow temperatures to
climb, with low 50s expected for Monday.
By Tuesday into Wednesday, the jet digs into the central Plains and
another wave looks to cross the Dakotas. An inverted surface trof
will cross the area and abundant moisture is available for
measurable precipitation. Expect rain initially ahead of and along
the trof, with cooler air and moisture wrapping behind the system
where some measurable snow is possible as the low slows with a
negative tilt trof aloft.
By Friday, the low departs and temperatures rebound as more pleasant
weather settles across the area.
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1030 PM CDT Fri Apr 1 2022
Showers have cleared all the TAF sites, for the most part.
Possibility for a sprinkle in Bemidji as we approach 06z. Clouds
will yo-yo in height across the area tonight and Saturday, but
should remain in VFR to MVFR levels. Clouds will mostly affect TAF
sites in Minnesota, but could also seep into the Red River
Valley. Winds will shift to northerly over the course of the day,
then another wind shift to easterly will come in the evening on
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
919 PM CDT Fri Apr 1 2022
Issued at 915 PM CDT Fri Apr 1 2022
No significant changes are needed to the forecast this evening. A
surface low will develop east across northern Illinois through the
day tomorrow, delivering a brief period of rain and some snow to
the region. Large scale forcing is forecast to be quite impressive
with this system, and mid-level lapse rates along its northern
flanks will additionally steepen appreciably. The 00Z HRRR has
shifted a bit farther north with the progged surface low track,
and is now better-aligned with the multi-model consensus which
shifts the low essentially right along or just south of I-80. Given
the lack of a colder antecedent airmass, snow accumulations (on
pavement) will likely be muted, even in the face of what could be
brief heavier rates as intense DCVA pinwheels overhead through
midday and early-afternoon. Any slushy snow accumulations will
require these heavier/convective type rates, and with the
northward shift in the HRRR, guidance is in pretty good agreement
that this zone will exist mainly north and west of a roughly Amboy
to St Charles to Waukegan line. In fact, the latest RAP-derived
Bourgouin melting energies suggest that outside of a little mix as
precipitation initially develops, locales farther south of I-88
will likely remain mainly rain.
The going forecast handles the expected evolution of things well.
Perfect-progging model output snow depth (likely a much better
proxy for actual snow accumulations in this case) suggest up to
2 inches of snow back towards parts of Ogle, Winnebago, Boone, and
northern DeKalb counties. Given expected window of higher rates,
could see a little slush accumulate on secondary/elevated
surfaces, but continue to suspect travel impacts will be limited
(and more problematic may be the reduced visibilities in any
heavier rates). Much of the snow that does manage to accumulate on
grassy surfaces will probably be melted by late tomorrow evening.
Issued at 321 PM CDT Fri Apr 1 2022
Through Saturday night...
The main forecast concern during the period continues to center
around the threat for a period of wet snow across portions of far
northern IL (primarily along and north of I-88 and west of the
Fox Valley) on Saturday morning. While temperatures are expected
to be hovering at or above freezing, some accumulations are
possible with this activity (especially on grassy and elevated
surfaces), due to the increased chances for heavier rates of snow
in the morning. While this is the case, uncertainty continues to
be higher than normal with overall snow accumulations and overall
travel impacts beyond reduced visibilities.
Our main weather marker for Saturday is an upper level short wave
impulse currently noted in the water vapor imagery digging
southeastward across eastern Montana. This impulse is forecast to
dig southeastward and phase with a larger scale trough over Iowa
and northern IL Sunday morning. The net result of this being the
development of a compact surface low that will move eastward
across the area during the day. The disturbance will undoubtedly
produce precipitation across a vast majority of the area though
most of the day. In most areas, the boundary layer will remain
just warm enough for this precipitation to fall as a cold rain.
However, there is concern that precipitation rates could become
high enough to result in stronger column cooling and a shift over
to a period of heavy wet snow Sunday morning, primarily over far
northern IL. This concern for heavier precipitation rates revolves
around the fact that forecast guidance is fairly consistent in
developing a mesoscale band of 850-700 mb frontogenesis beneath
the entrance region of an upper level jet streak right across far
northern IL during the morning. The combined effects of this with
the larger scale forcing for ascent would thus support a narrow
band of enhanced forced mesoscale ascent, and hence an area of
heavier precipitation rates potentially falling as heavy wet
Guidance continues to differ a bit on the favored location for
this mesoscale area of frontogenesis, with some continuing to
favor areas north of I-88 in and around the Rockford, IL region.
However, other hi-res models suggest areas a hair farther south,
closer to the I-80 and I-88 corridors. This adds uncertainty to
exact placement of this possible area of snow, which may only be
a county or so wide (~30 miles wide). Wherever this band of snow
sets up the potential is there for a few inches (1 to 3 inches) of
wet snow, but this may be mainly confined to grassy areas and
elevated surfaces due to the most of the snow falling after
daybreak. The early April sun angle will certainty make it
difficult for much in the way of accumulation on paved surfaces,
so actual travel impacts may only be limited to reduced
visibilities, which could drop below a mile in the heavier snow.
The potential for accumulating snow will generally begin to wane
late in the morning and the afternoon as surface temperatures
warm. Some rain will continue into the afternoon before it ends
later in the afternoon following the eastward exit of the storm
system. We have opted to hold off on issuing a winter weather
advisory for the Rockford area given the possibility of limited
travel impacts with this snow, but this will need to be monitored.
Issued at 310 PM CDT Fri Apr 1 2022
Sunday through Friday...
An active weather pattern will continue through next week, with
high confidence in another round of precipitation (mainly or
entirely rain) later Sunday into early Monday, and then
additional chances in the mid to late week. Temperatures will
average out near to a bit below normal through Wednesday, and
then trend to solidly below normal to close out the work week.
This will occur as a slow moving deep upper low meanders eastward,
which may unfortunately bring the threat for the "S" word at times.
Sunday will start out partly cloudy but trend to mostly cloudy in
the afternoon upon the approach of our next system. High temps are
forecast in the mid to upper 50s south of I-80 and lower to mid
50s north, except only 40s as is typical this time of year near
the lake due to early lake breeze passage. A similar evolution to
Saturday, but probably shifted farther north, is forecast Sunday
night as a potent, compact short-wave and associated surface low
Some spotty light showers may break out near I-39 in the mid to
late afternoon out ahead of the stratiform rain with some banded
component Sunday evening night. Most of the guidance features a
low track near or north of far northern Illinois, with exception
of most recent Canadian global. Confidence is higher in rain as
p-type, with moderate rates at times, though still can`t rule out
farther south low pressure track and wet snow mixing in with
northward extent. Could be some spotty showers lingering beyond
sunrise Monday, but otherwise drying out. Monday`s forecast high
temps are similar to Sunday, though warmer near the lake until
mid-late afternoon lake cooling.
Confidence is increasing in Tuesday being mostly dry, but we`re
still holding onto some lower PoPs due to influence of recent GFS
suites featuring a stronger and farther north southern stream
wave. Suspect that the weaker and farther south scenario with dry
easterly flow locally is more likely to win out, entailing 50s for
most except 40s along and several miles inland of the Illinois
lakeshore. A potent already closed off mid-level short-wave will
eject from the Canadian Prairies to the northern Plains on Tuesday
night. Meanwhile, a strong short-wave farther south (and strong
upper jet) with associated surface low extending up to the mid MS
Valley, will phase with the northern Plains short-wave into
A band of rain showers will break out and rapidly shift eastward
through Wednesday morning, with a brief warm sector bringing
seasonable temps, followed by cold frontal passage. At this time,
moisture return looks to be too little too late for noteworthy
thunderstorm coverage and official mention in the grids, as
steeper lapse rates look to arrive behind the cold front. Can`t
rule out some isolated embedded thunderstorms in the warm
advection regime Wednesday morning. Later Wednesday and onward,
our weather will be influenced by the large upper low gyre that
will form from phasing short-waves on Wednesday. While there is
inherent uncertainty at this range, ensemble guidance remains in
good agreement in crawling the upper low east-southeast through
Thursday night and then east-northeastward Friday into next
weekend (beyond current day 7). The pattern will be pseudo-blocky
due to strong positive height anomalies surrounding the closed low
and result in slow forward propagation of the upper low.
The impressive cold pocket for April with 500 mb temps down to as
cold as -30C or so will result in waves of showers associated
with short-wave energy pivoting around the upper low gyre. These
patterns with low tropopause heights and inherently steeper low
and mid-level lapse rates can result in showers with graupel
during diurnal instability maximum, which could be the case on
Thursday. Northerly flow on the backside of the surface low
reflection later Thursday night and Friday could allow wet snow to
mix in if not a changeover, particularly Thursday night into early
Friday. Highs will only be in the upper 40s to around 50 on
Thursday and at best mid to upper 40s on Friday.
For the 00Z TAFs...
Winds will settle SSE under 10 knots tonight amid VFR conditions.
A compact low pressure will then move eastward across northern
Illinois through the day Saturday. Precipitation type will depend
heavily on the exact track of the low, with the expected track to
be very close to or over Chicago. With this track, precip type in
the Chicago metro will be primarily RA, with some SN mixing in for
the first couple hours before low-level thermo profiles slowly
warm. However, a farther south track by even less than 50 miles
will significantly increase the chance of SN becoming the dominant
precip type at ORD/MDW. In either case, the window of highest
precip rates will be late morning into early afternoon, with
periods of IFR visibility and a trend toward IFR ceilings
expected. Wind direction will also depend on the exact track of
the low, with confidence in direction low in the afternoon given
the potential for the low to track over the Chicago terminals. The
current forecast favors SE winds briefly becoming light NE or VRB
before quickly backing NW around 10 knots by early evening.
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Area Forecast Discussion
National Weather Service New York NY
1044 PM EDT Fri Apr 1 2022
Deepening low pressure continues to move northeast from the
Canadian Maritimes overnight as high pressure builds to the
west. The high then builds in for Saturday. An area of low
pressure approaches from the west on Sunday and moves offshore
Sunday night. Weak high pressure builds in on Monday and moves
offshore by Monday evening. A complex frontal system will
approach on Tuesday and bring unsettled weather to the area
through the end of next week.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Another upper vort max was moving through the area as the
associated upper trough moves offshore overnight. This was
producing broken to near overcast conditions, with strato cu
across much of the region. Updated temperatures and dew points
for current conditions, and with the extensive cloud cover
raised overnight lows, mainly inland, a couple of degrees.
Gusty winds will continue through the overnight with the
pressure gradient remaining fairly tight between the departing
low and building high. Winds will begin to weaken toward
morning. HRRR 10m gust potential depicts gusts starting to come
down after 06Z.
In addition, with the growing season starting today for NYC and
immediate surrounding areas, some patchy frost may be possible
by Saturday morning, with lows in the mid 30s. This is not
expected to be widespread, but could be realized across parts of
the area should winds subside earlier than currently forecast.
Lows tonight generally in the mid to upper 30s across
northeastern NJ, LI and NYC, and in the upper 20s to low 30s
across CT and lower Hudson Valley.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
Upper ridging builds in for Saturday and with subsidence aloft,
a generally quiet sensible weather day is expected. With dry
conditions and west/southwest flow, expect temperatures similar
to Friday, a few degrees cooler given the lower starting point.
Conditions remain dry Saturday night with increasing clouds as
a low pressure system and attendant shortwave trough approach
from the west. 12Z model guidance is showing a slightly stronger
system than in previous cycles, with the upper trough slowing
as it moves across the OH Valley into New England. Guidance is
fairly consistent with the surface low tracking across PA and
upstate NY Sunday morning and offshore by later Sunday
afternoon. Have increased PoPs and QPF as a result, with total
amounts around 0.15-0.20 inches during the day. Given the model
thermal profiles early Sunday, there is a low potential for some
snow to mix in at the onset of the precipitation across the far
interior Hudson Valley, but this is not expected to be
widespread or accumulating. Precipitation ends west to east by
Highs on Sunday will be in the upper 40s across the interior, and
low 50s elsewhere.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Upper level trough axis shifts east Sunday night as low
pressure moves offshore. Some rain showers could still be
lingering over eastern portions of CT, but after midnight the
area is expected to be dry. Skies clear from west to east, and
depending on wind, some locations will be able to take advantage
of radiational cooling and drop to their lowest temperatures of
the long term period. Interior locations in CT and the Lower
Hudson Valley will be the coldest, with lows in the lower 30s.
Shortwave ridging approaches on Monday and flattens out as
heights rise over the area. At the surface, weak high pressure
briefly builds in, but the center passes to our south and west
and slips offshore. Dry conditions with highs right around
normal, low to mid 50s, can be expected.
For the rest of the week, a broad upper level trough will be
deepening over the central CONUS and slowly progressing
eastward. This is well agreed upon by guidance, with -2 to -3 SD
in 500mb heights from the Great Plains to the southeastern US
in all Ensembles. Where guidance does disagree is how a piece of
energy behaves in front of the aforementioned trough. The
European and Canadian deterministic models pass this disturbance
farther to our south along with surface low pressure. The GFS
deterministic wants to bring this feature a bit farther north.
Both situations will bring rain to our area. With moisture being
brought northward from the Gulf of Mexico, the GFS is showing a
PWAT value around 1.25 inches. This would allow for some
moderate or even heavy rain showers. This value is above the
90th moving average for OKX based on SPC`s Sounding Climatology
As the aforementioned broad upper level trough continues to shift
east, complex broad low pressure at the surface will result in
unsettled weather through the end of the week. There will be a
period on Thursday with a few hundred J/kg of MUCAPE across the
eastern half of the area ahead of a cold front. With some elevated
instability thunder can not be ruled out, but being this far out
confidence in timing is low and have left out of the forecast for
now. PWAT values look to be well above average on Thursday as well.
Temperatures during the long term will be close to normal and have
stuck closely to NBM.
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Deepening low pressure over the Canadian Maritimes will
gradually pull away to the NE, while high pressure builds in
from the west overnight into Saturday. The high moves offshore
VFR. A strato cu deck, 5K to 7K ft, has been moving into the
area as the west to northwest flow continues behind departing
low pressure, and will likely remain until toward morning.
W/NW winds 15 to 25kt, gusting 25 to 30kt diminish overnight
into Saturday morning with the gusts ending around midday. Winds
veer to W then SW during Saturday afternoon, 10kt or less. Late
day seabreezes develop. Timing of the diminishing winds and
gusts may be off +/- an hour or two.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
West to northwest winds and gusts will be diminishing through
the overnight into Saturday morning. Timing of the end of the
gusts may be off +/- an hour or two. Sea breeze at KJFK may be
earlier than 22Z.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
.Sunday...MVFR possible. Showers, possible brief mix with snow
across parts of interior in the morning. Showers taper off in
.Tuesday...Chance of MVFR with any isolated showers early in
.Tuesday Night-Wednesday...MVFR/IFR with showers likely.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
No changes to winds and seas at this time.
Tight pressure gradient across the waters will continue to
cause gusty northwest winds into early Saturday. SCA conditions
continue for all waters with wind gusts 25-30 kt into this
evening. Gale warnings remain in effect for the ocean tonight
and through early morning Saturday as winds are expected to gust
35-40 kt ahead of a secondary cold front expected to move
Winds should diminish by daybreak Saturday morning but wave
heights may remain elevated through midday to at least SCA
thresholds on the ocean. Otherwise, sub-SCA conditions are
expected on the non-ocean waters.
As low pressure departs Sunday night, wind gusts on the ocean waters
could briefly reach SCA criteria. Below SCA criteria then expected
through Tuesday night. Winds become easterly ahead of a complex
frontal system on Wednesday and seas begin to build. Seas likely
remain above 5 ft through the end of the forecast period. During
this same time, 25 kt gusts are possible on the ocean waters.
No hydrologic impacts are expected through the end of next week.
MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ331-332-
Gale Warning until 4 AM EDT Saturday for ANZ350-353-355.