Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/28/20
Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CDT Mon Apr 27 2020
.UPDATE...
Issued at 957 PM CDT Mon Apr 27 2020
Scattered rain showers continue across portions of southwest and
south central North Dakota this evening. Linton and Fort Yates
NDAWN stations have both reported a few hundreths of
precipitation, and the Linton ASOS also reported moderate rain for
a bit, so increased POPs in the south central in line with the
better area of radar reflectivity associated with the reported
rain. Kept POPs to the west lower since haven`t seen any reports
of rain. Went ahead and took out the chance for isolated
thunderstorms for the night since it`s been a few hours since
we`ve seen any lightning close to the forecast area. Otherwise
only minor changes to the forecast with this update.
UPDATE Issued at 655 PM CDT Mon Apr 27 2020
Rain was reported at both the Hettinger ASOS and Hettinger NW
NDAWN station from 22 to 23Z, so have some confidence that
precipitation shown on radar is making it to the ground in at
least far south central North Dakota. Our 00Z RAOB shows very dry
air up to about 10K feet, but we did see rain on windshields here
at the office, so guessing there will still be some very light
rain falling in places before the atmosphere becomes more
saturated leading to more persistent rain showers. Updated POPs
with the latest high- res guidance, but no major changes with
timing or location. There was some lightning in northwest South
Dakota, so kept chance of isolated thunderstorms in for this
evening.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 217 PM CDT Mon Apr 27 2020
A strong frontal passage will bring gusty northwest winds and
possibly critical fire weather conditions to much of western North
Dakota on Tuesday. Winds gusting up to 50 mph and minimum relative
humidity values in the low 20s are expected in the southwest
portion of the state.
This afternoon, weak surface pressure falls were ongoing over
western South Dakota and southwest North Dakota as a surface low
deepened in response to a shortwave detected on water vapor
imagery over northern Idaho and western Montana. As this shortwave
continues to propagate through quasi-zonal this evening,
increasing low level convergence should develop precipitation in
far southwest North Dakota and move east through the night. Mid-
level lapse rates in the 7-7.5 C/km range were advecting into our
southwest. Atop a well-mixed and moisture deficient boundary
layer instability values will be on the low end, but possibly
enough for updrafts to form with lightning potential this evening.
In the case that a more rigorous thunderstorm is able to develop,
the inverted-V profile in forecast soundings may contribute enough
acceleration of descending air parcels to produce some gusty
winds.
Upstream of the aforementioned shortwave, another mid-level
shortwave was detected over the Pacific Northwest. This wave is
expected to drop southeast and intensify under the influence of
the left exit region of a 120 kt jet nosing in from the northwest.
As western North Dakota is placed under the brunt of the post-
frontal northwest flow regime, surface winds are expected to
increase through the morning as efficient momentum transfer
becomes more prevalent in an increasingly mixed boundary layer
profile. Wind gusts should be greatest and approaching 50 mph in
the southwest portions of the state. Additionally with another
passage of dry air relative humidity will be low once again.
Blending in RAP dew point guidance, which has performed well in
high mix- out expected days, relative humidities down to 20
percent were added to the forecast. However high-resolution
ensemble guidance (HREF) shows a healthy potential for even lower
dew points and relative humidities. So while a Fire Weather Watch
was issued to cover this potential, the coverage and magnitude of
critical fire weather conditions certainly has the potential to
increase.
Scattered showers and possibly thunderstorms should develop as the
mid-level low becomes more closed and wrap-around moisture with
ongoing lapse rate advection develops instability during the day.
12Z NAM and 18Z RAP guidance advertises 500-1000 J/kg of MLCAPE
which seems reasonable. Weak mid-level flow producing low shear
values should prevent any severe thunderstorm concern. Between
precipitation and the post-frontal air mass, high temperatures
will be relatively cooler with temperatures in the 60s expected.
.LONG TERM...(Tuesday night through Monday)
Issued at 217 PM CDT Mon Apr 27 2020
A warming trend is expected for the middle of the week with highs
on Thursday of around 80 possible in the western portion of the
state. Chances for precipitation return late in the week through
the weekend.
A seasonably strong ridge is forecast to build over the
Intermountain West by Wednesday morning. Stiff mid-level height
rises and subsidence are expected with a surface high forecast to
drift over the Dakotas through the day Wednesday. We should expect
generally light winds with mostly clear skies and highs in the 60s
and 70s. The upper level ridge axis will center over the Northern
Plains on Thursday with warm air advection at 850mb and southerly
surface flow expected to boost highs to what should be the warmest
of the forecast period. Widespread 70s with areas of the west
reaching around 80 are forecast.
Guidance remains consistent in driving a shortwave trough over the
ridging pattern Thursday night through Friday, bringing chances for
showers and thunderstorms. With the high pressure pattern locked in
to our south it is reasonable to say at this point best chances for
precipitation should be in the northern portions of the state, with
more uncertainty further south. 12Z GFS/ECMWF do hint at some
instability developing ahead of the frontal passage expected on
Friday, with potential for stronger thunderstorms dependent on
still an uncertain wave timing and amplitude.
Deterministic and CIPS ensemble guidance displays mean troughing in
place over the Hudson Bay region with northwest cyclonic flow over
the Northern Plains through the weekend. A relative cool-down with
periodic chances for precipitation will accompany this pattern.
Though details are currently fuzzy, guidance is consistent in
bringing a stronger low through the region early next week with
increased chances for precipitation in the NBM.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 655 PM CDT Mon Apr 27 2020
Scattered showers are expected to continue across parts of
southern North Dakota through 12Z, with isolated thunderstorms
possible. VCSH included in KBIS/KJMS but overall confidence in
timing and location is low. More showers are possible on Tuesday
as a cold front moves through the area, with the best chance of
showers at KMOT/KJMS Tuesday afternoon. Winds will shift to be
northwesterly behind the front, with the strongest winds expected
in southwest North Dakota, gusting as high as 40 knots.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Tuesday afternoon through Tuesday
evening for NDZ017-018-031>033-040-041-043-044.
Wind Advisory from 9 AM to 8 PM MDT Tuesday for NDZ031>033-040-
041-043-044.
&&
$$
UPDATE...MJ
SHORT TERM...AE
LONG TERM...AE
AVIATION...MJ
Area Forecast Discussion
National Weather Service Caribou ME
1040 PM EDT Mon Apr 27 2020
.SYNOPSIS...
Low pressure will slowly track well south of the Gulf of Maine
overnight. High pressure build southward from Quebec tonight
later Tuesday into Wednesday. Another low will approach the area
from the west Thursday and cross the region later Friday.
&&
.NEAR TERM /THROUGH TUESDAY/...
1040 PM Update...Pops were adjusted to match the latest radar
trend showing some light precip backing into Maine from New
Brunswick. The trend was to adjust the higher pops toward the
coast. The latest RAP showed precip trends weakening and
shifting s overnight w/the convergence weakening. Hrly temps
were adjusted for current conditions. Given the clouds, only
modest adjustments were made to the overnight temps.
Previous Discussion...
Steady northeast winds will continue through the night with
generally cloudy skies. As the blocking high sets up over the
area, the very dry air in northern zones will spread south
tomorrow. Temperatures will be warmer without any precipitation
and less cloudiness. A deep mixed layer is expected tomorrow
which will ensure lower dew points than guidance and stronger
winds.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Sfc low wl be well south of Labrador by the start of the period. Sfc
ridge axis wl be building twd the CWA fm Canada with axis bisecting
the area by 12z Wed. Skies wl be clearing late and winds near calm
may allow for radn`l cooling, especially over the northwest zones
with mins dipping into the mid-20s.
By Wed morning winds wl veer around to the south ahead of system mvg
thru the Great Lks. This system is currently slamming into the
British Columbia coast this afternoon. It wl head east thru the srn
Prairie Provinces drg the day tomorrow before diving twd the MS Rvr
Vly Wed afternoon. H5 ridge pumps up significantly ahd of this
deepening low with 500 heights rising to 565+ leading to maxes u50s
to nr 60 acrs a fair chunk of the region. Skies wl begin to cloud up
as the system approaches on Wed night.
By Thur morning all areas wl see cldy skies with pcpn mvg into the
far wrn zones by daybreak. May see a rain/snow mix acrs the
northwest as temps dip to nr 30F but quickly rebounding and going
over to rain by mid-morning.
Due to the extensive cloud cover and rain over the entire region
high temperatures on Thu will be slightly blo normal with m/u 40s
over the North Woods and around 50F over the remainder of the area.
LLJ of 35-45 kts wl begin to kick in during the afternoon.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Strong H8 jet rmns over the region Thu night into Fri. PW values wl
be increasing thru the early part of the extndd pd with mid-level
moisture mvg straight in fm the Atlantic. Area wl be in the RRQ of
upr-lvl jet streak with dynamics likely leading to locally heavy
rainfall. Cannot rule out possible thunder as well, which will lead
to heavier rainfall amnts. Latest EC is giving widespread 1-1.25
inches amount Friday and Friday night. Expect lingering showers thru
Sat night with another quick s/wv zipping acrs the FA thru the end
of the pd.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: LLWS will affect all sites tonight. Gusty northeast
winds will slowly diminish overnight. All sites will be VFR
except coastal sites such as BHB and Machias will feature MVFR
cigs with tempo IFR vis in snow showers tonight. All sites will
be VFR Tuesday.
SHORT TERM:
Tue night-Thu morning...VFR. Light NE winds Tue night becoming
SE Thu morning.
Thu...Becoming MVFR all sites during the afternoon. S 5-10kts
gusting to 15-20kts.
Thu night-Sat...IFR all sites in rain, locally heavy. SE 10-15kts
Fri becoming N Sat morning. Possible LLWS Thu night and Fri.
&&
.MARINE...
NEAR TERM: Gale conditions will end late tonight and a Small
Craft Advisory will be needed in its place into midday Tuesday.
The long period southerly swell will slowly diminish tonight.
SHORT TERM: Below SCA conditions into Thursday morning before
winds begin to increase out of the SE ahead of next system
moving in from the west. Seas increase above 5ft in serly swell.
SCA conditions through Fri morning. Gales possible during the
day on the outer waters but gusts are marginal at this point.
Seas remain elevated thru Sat afternoon with SCA likely
continuing into Sat.
&&
.FIRE WEATHER...
Continued dry conditions in northern zones with low relative
humidity and gusty northeast winds raise fire weather concerns
for Tuesday. Expect a deep mixed layer which led to reduction of
dew points below guidance and increased wind gusts. Temperatures
will be a bit warmer into the lower 50s. A wetting rain that
occurred today into tonight towards the coast mitigates concern
for that area.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Gale Warning until 6 AM EDT Tuesday for ANZ050>052.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Duluth MN
646 PM CDT Mon Apr 27 2020
.UPDATE...
Issued at 536 PM CDT Mon Apr 27 2020
Issued a Marine Dense Fog Advisory along the North Shore and down
into the Twin Ports area based on Satellite and web camera
imagery. The HRRR keeps the low visibilities around till Tuesday
morning.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 309 PM CDT Mon Apr 27 2020
Isolated showers percolated over northern St. Louis County this
afternoon ahead of a weak cool front. As one of the more vigorous
showers (35-40 dBZ returns) passed over Orr, the AWOS reported a
trace of rain. Cumulus were found over northern parts of the
county and much of Koochiching County. Cumulus were smaller and
more isolated elsewhere across the Northland. Think a few
sprinkles will continue to percolate over northern Minnesota this
afternoon ahead of the front. Otherwise, dry conditions are
expected overnight. Areas of fog are possible overnight due to the
combination of relatively light winds and clear skies, with
morning rainfall.
An area of low pressure will move eastward out of South Dakota
and across northern Iowa and southern Minnesota Tuesday into
central and southern Wisconsin by Tuesday evening. A secondary low
may take shape over the Canadian Prairies tonight and move into
northwest Minnesota on Tuesday. Between these two systems, much of
the Northland will see at least a chance of showers. The best
potential for rainfall is from the Brainerd Lakes area east into
northwest Wisconsin. Rainfall amounts of one- to three- quarters
of an inch are possible in those areas with lower totals farther
north. With the passing area of low pressure on Tuesday, look for
northeast winds over western Lake Superior. The onshore flow will
keep temperatures cool along the shore and inland into the I-35
corridor. Precipitation chances will shift eastward as the
southern low departs the area early Wednesday. Highs on Tuesday
will reach the low and middle 40s near the Lake Superior shore to
the middle 60s in Koochiching County.
.LONG TERM...(Wednesday through Monday)
Issued at 309 PM CDT Mon Apr 27 2020
Relatively quiet for much of the long term with a chance of
showers or thunderstorms Friday afternoon through Saturday
morning.
A few lingering showers will depart Wednesday morning as a
surface low over southern Wisconsin departs to the east. Cold air
advection and cyclonic flow aloft may touch off a few isolated
sprinkles Wednesday afternoon. High pressure settles over the
region Wednesday night through Friday morning with quiet
conditions expected. Temperatures will trend warmer for Thursday
with highs in the 60s to low 70s except near the Lake Superior
shore and portions of northwest Wisconsin where temps will be
limited to the 50s. Onshore winds will be less of an issue for
Friday and temperatures should be in the upper 50s to low 60s for
most areas, except low to upper 50s along the North Shore.
A compact shortwave trough will move across the Canadian Prairies
and into northwest Ontario Friday and Saturday. A cold front will
accompany the low and will set the stage for showers and
thunderstorms over northern Minnesota Friday afternoon through
Saturday morning. Temperatures will be similar on Saturday with
highs in the 60s for most areas, except 50s along the North Shore
and possibly a few 70s in the St. Croix River Valley. A few
degrees cooler on Sunday as another cold front sags south across
the Northland. There may be a few showers associated with that
front. Highs will be in the upper 50s north to middle and upper
60s south.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 645 PM CDT Mon Apr 27 2020
VFR conditions to start the forecast off. Fog can be observed over
Lake Superior and the light winds out of the east are gradually
bringing it inland. Along the eastern portions of the Arrowhead a
saturated surface combined with light mixing winds will stir up fog
conditions overnight and into the morning hours. Look for DLH/HIB to
have visibility reductions to IFR and possibly LIFR. Fog is expected
to stick around into the later morning hours when the sun begins to
disperse the low cloud, visibilities will then rise to MVFR.
Tomorrow a low pressure system makes its way across the Midwest with
its northern precipitation field clipping central MN and NW WI.
Light rain showers are forecasted for BRD/HYR with ceilings dropping
to MVFR in the afternoon for HYR.
&&
.MARINE...
Issued at 536 PM CDT Mon Apr 27 2020
A northeast wind continues to impact Lake Superior. Dense fog
clouds can be seen on satellite beginning to migrate along the
North Shore and down into the Twin Ports area. A dense fog
advisory has been issued until Tuesday 10am. Winds will begin to
pick up Tuesday afternoon with sustained winds between 10-20kts
and gusts upwards of 25kts. With this increase in winds a Small
Craft Advisory may be needed for portions of the southwest arm of
Lake Superior.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 37 47 36 55 / 10 50 30 20
INL 36 62 37 61 / 0 20 20 0
BRD 43 55 40 62 / 10 80 40 10
HYR 40 57 38 55 / 10 90 80 30
ASX 36 48 36 50 / 10 70 50 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Dense Fog Advisory until 10 AM CDT Tuesday for LSZ140>145.
&&
$$
UPDATE...Britt
SHORT TERM...Huyck
LONG TERM...Huyck
AVIATION...Britt
MARINE...Britt
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
650 PM CDT Mon Apr 27 2020
.SHORT TERM...(This evening through Tuesday)
Issued at 328 PM CDT Mon Apr 27 2020
Forecast concerns in the near term revolve around precipitation
chances and fire weather concerns on Tuesday.
Tonight, a shortwave and associated cold front will approach the
area from the northwest. This may allow a few showers and perhaps
a weak thunderstorm or two to develop after midnight tonight
through daybreak on Tuesday. That said, most spots will only see
sprinkles, at best. Even the HRRR (which is usually on the higher
end of QPF) only has a trace through Tuesday morning.
As the front passes through the area on Tuesday, we will see
gusty northwest winds develop behind it. Sustained winds will
average around 25 MPH with gusts to around 40 MPH during the
afternoon. For more information on the fire danger, see the fire
weather section below.
Models have now latched on to the idea that we will have some
lapse-rate driven showers and possibly an isolated thunderstorm or
two Tuesday afternoon and early evening. Severe weather is not
expected, but additional mixing from any showers may provide
localized enhancement to the already strong northwest winds. This
activity should end by late evening, allowing skies to clear and
temperatures to fall into the 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 328 PM CDT Mon Apr 27 2020
The bulk of the long-term forecast is relatively quiet. Wednesday
will bring another day of fire weather concerns, albeit with
lighter winds than on Tuesday.
With high pressure overhead, Wednesday night will be the coldest
night of the forecast period. Lows are expected to drop into the
upper 30s to low 40s.
Winds will then switch around to the south for Thursday and
Friday as upper level ridging amplifies over the western half of
the CONUS. By Friday, high temperature should push into the mid
80s to low 90s across the area. For now, its not looking like
we`ll get to record-breaking territory, but it is a very warm
start to May nonetheless.
The ridge begins to break down as a weak perturbation moves in on
Friday. As it does so, the GFS tries to generate some light
showers in the area. That being said, better chances for rain and
thunderstorms won`t arrive until Saturday or Sunday as a more
substantial trough breaks down the ridge. Temperatures will trend
cooler and closer to climatological normals through the weekend
and into early next week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 629 PM CDT Mon Apr 27 2020
VFR conditions are expected through the period although the period
will not be uneventful with very gusty winds anticipated during
the daytime hours Tuesday along with a small chance of
thunderstorms late tonight and again during the afternoon hours
Tuesday.
While light and variable winds and VFR CIGS are the norm
across the local area this evening...expect a cold front to bring
additional cloud cover and a shift in winds to the local area
overnight. Thunderstorm chances are expected to remain mainly
north of both terminals overnight...but did include a VCTS at both
sites aft 28/08Z just in case. After daybreak...expect winds to
really ramp up out of the northwest...with gusts to 35KTS+
expected during the afternoon hours. In addition...a second
disturbance will also bring back a small chance for thunderstorms
late in the day Tuesday...and included an additional mention of a
VCTS at both sites to account for this.
&&
.FIRE WEATHER...
Issued at 328 PM CDT Mon Apr 27 2020
Although we are starting to see a green-up across the area, there
is still an abundance of dead grasses from the very wet 2019
season. These fuels will still support a wildfire threat given
sufficiently strong winds or low RH. This threat is exacerbated by
how dry we have been recently. Satellite-derived greenness data shows
that our green-up is lagging a bit slower than normal, and
observations across the area supported this...especially west of
Highway 281.
On Tuesday, the strong northwest winds will make any fires that
develop very difficult to control. Therefore a RFW was issued for
Highway 281 westward. Relative humidity may not be low enough to
reach the 20 percent criteria across northern portions of the
area, but it will still be dangerous fire conditions, nonetheless.
Winds may also become erratic if any thunderstorms develop in the
afternoon.
Another round of fire weather concerns are possible on Wednesday.
Winds will start to taper off in the afternoon, but humidity will
likely be lower...possibly around 15 percent in southwestern
portions of the area.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Red Flag Warning from noon to 8 PM CDT Tuesday for NEZ039-040-
046-047-060>062-072>075-082>085.
KS...Red Flag Warning from noon to 8 PM CDT Tuesday for KSZ005-006-
017-018.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Rossi
FIRE WEATHER...Mangels
Area Forecast Discussion
National Weather Service Grand Rapids MI
1018 PM EDT Mon Apr 27 2020
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 324 PM EDT Mon Apr 27 2020
- 7-day Forecast Overview
- Tonight`s Rain
- Mid Week Rain...possibly heavy...Tuesday night - Thursday
- Few showers on Saturday
&&
.UPDATE...
Issued at 1018 PM EDT Mon Apr 27 2020
Have added areas of fog to the forecast later tonight as latest
RAP fcst soundings indicate considerable low level moisture
developing after the current light rain and mid clouds move out.
The fog may become dense, but confidence too low at this time to
go with a Dense Fog Advisory. Since the moisture will be shallow,
expect any fog that develops to mix out rapidly early Tuesday.
With enough sun, highs could easily top 70 but that will depend
on extent of mid and high cloudiness.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 324 PM EDT Mon Apr 27 2020
-- 7-day Forecast Overview --
We are looking at a fairly active pattern over the course of the
next 7 days. A zonal flow in place to start the forecast tonight,
quickly becomes amplified into mid week as a shortwave currently in
the Pacific Northwest dives through the Northern Plains. By
Wednesday the upper low is closed off and moving through the Great
Lakes. Widespread rain that may become locally heavy is the main
story in the forecast.
The flow becomes zonal again over the weekend. Temperatures through
the period will be fairly seasonable. Normals are highs around 60
and lows around 40 and we will not be far off from those numbers.
The exception will be on Thursday when we will be solidly colder
than normal with clouds, rain and a north flow. Highs may end up
being around 50 or 10-15 degrees below normals.
-- Tonight`s Rain --
The rain has already spread into West Central Lower Michigan as of
300pm. We are still thinking this rainfall will be on the order of
0.10 to 0.30 inches with a few higher streaks possible. The rain is
associated with a quick moving shortwave in the northwest upper flow.
The rain should come to an end overnight, probably around 300am.
-- Mid Week Rain...possibly heavy...Tuesday night - Thursday --
The main show this week is the low pressure system that moves right
through the forecast area. See hydro discussion below for the
details, but a widespread soaking rain appears to be in the offing.
We cannot rule out a rumble of thunder at times, especially Tuesday
evening, but this will be more of a rain event as opposed to
something that is highly convective. Both the GFS and the ECWMF
deterministic runs have a sub 1000mb low moving through the area
that will be interacting with PWATS that will be up towards 1.25
inches. The heaviest rain should come Tuesday night which is when an
850mb LLJ impinges on a warm front aloft over our area. These type
of events seem to be predisposed to overperform, so we shall see.
The upper low slowly spins through the area from Wednesday into
Thursday as showery upper low precipitation turns into wrap around
deformation zone precip. Suffice it to say we look wet from Tuesday
evening into Thursday.
-- Few showers on Saturday --
After Thursday conditions dry out considerably for the remainder of
the forecast through next Monday. The exception is on Saturday when
a moisture starved front pushes through the region. We are not
expecting anything too heavy with this front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 751 PM EDT Mon Apr 27 2020
Despite rain moving through the area this evening, VFR conditions
are prevailing with cig heights around 5000 ft. The pockets of
heavier rain are producing MVFR vsbys of 4-5 miles at times. All
of this rain moves out later this evening, then the concern
becomes the formation of low stratus clouds and fog overnight.
Will feature a period of IFR/LIFR cigs/vsbys late tonight into
early Tuesday, with the lowest conditions/vsbys expected west of
LAN and JXN. The stratus and fog will mix out rapidly on Tuesday
morning, leaving VFR weather.
Some showers and perhaps a tstm may develop south of I-96 after
21-22Z Tuesday, but have left that out for now since timing and
coverage of the next batch of rain is low confidence at this
time.
&&
.MARINE...
Issued at 324 PM EDT Mon Apr 27 2020
Conditions on the big lake look to be spring like, which is to say
fairly tame from Tonight through Tuesday night. Normally this time
of year winds and waves are lower due to the fact that the cold
water acts as a "bubble high" and does not allow winds to mix to the
lake surface. It takes a low pressure system, especially one tugging
down cold air from the north to kick up winds and waves.
One such system materializes mid week with a low tracking through
the Lower Great Lakes from west to east. On Wednesday into Wednesday
night northerly winds begin to fill in across Lake Michigan. The
latter half of the work weeks looks rough. Gale force winds look
likely in a north-northwest flow Wednesday night through at least
Thursday. I can see stronger north winds, if not gales, persisting
into Thursday night. Gale Watches may be needed for Wednesday night
and beyond.
Waves of 6 to 10 feet look likely, especially south of Grand Haven.
The worst of the erosion given the flow regime will be south of
Holland.
&&
.HYDROLOGY...
Issued at 324 pM EDT Mon Apr 27 2020
Several wet days are coming up for West Michigan. The good news is
that its been fairly dry lately, and our rivers are generally
starting things out with some space to give. In fact, many of our
rivers have slipped below the long-term average values in the last
week or so. Additionally, the trees and vegetation are starting to
leaf out and use more water this time of year, so that will help,
too. Nevertheless, the soils are not as dry as you might think, and
still cant hold as much as they could in some other years. This
will lead to increased runoff efficiency into the rivers for any
rain that falls over the next few days.
General expectations are for 1-2 inches of rain across the area
between this evening and Thursday afternoon, with a few areas higher
and a few areas lower. The rain will come in multiple waves, spaced
out by 12 hours or so, which will actually limit the rises on the
rivers. We are expecting most of our rivers to once again rise to
near bankfull, but unless our widespread rain totals trend higher
than the 2 inch mark, we should avoid significant flooding,
especially on the larger rivers.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Meade
SYNOPSIS...Duke
DISCUSSION...Duke
AVIATION...Meade
HYDROLOGY...AMD
MARINE...Duke
Area Forecast Discussion
National Weather Service North Platte NE
1057 PM CDT Mon Apr 27 2020
.SYNOPSIS...
Issued at 341 PM CDT Mon Apr 27 2020
H5 analysis this morning had a fairly benign pattern
across the CONUS. A shortwave trough was located over the Mid-
Atlantic with a second strong shortwave noted over northern
Minnesota. Another shortwave was located over southwestern Kansas.
Further west, a strong shortwave trough was off the coast of British
Columbia with weak embedded waves extended from southwestern Oregon
into northern Montana. At the surface, a weak surface trough
extended from east central Nebraska into south central Nebraska.
East of this feature, winds were southerly, while west of this
feature, winds were generally from the west or northwest, however,
some locations had some variable winds at under 10 MPH. Under clear
skies, 2 PM CDT temperatures ranged from 75 degrees at Gordon to
80 degrees at North Platte.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 341 PM CDT Mon Apr 27 2020
The main forecast challenges over the next 24 to 36 hours is fire
weather concerns and the small threat precipitation tonight and
again on Tuesday afternoon. For tonight: The shortwave, currently
over northern Montana, will approach the western Dakotas around
00z this evening. Increasing mid level warm air advection and
steep lapse rates, will lead to increasing chances for showers and
possibly a thunderstorm tonight. Forcing remains strongest north
of the forecast area with the best chances across the Dakotas.
Across northern Nebraska, decided to limit pops to slight chance
to low end chance tonight. This forecast was based on the QPF
forecast from the HRRR and GFS solns. The GFS and HRRR develop
very little precipitation in northern Nebraska tonight. The NAM12
and NAMnest solutions are more favorable, developing more pcpn
across northern Nebraska overnight. Feel more confident in the
GFS and HRRR solutions, based on their depiction of where the
current shortwave trough is upstream in Montana. Lows will be mild
tonight due to expected cloud cover with readings in the mid 40s
to the lower 50s. On Tuesday, a secondary, stronger shortwave,
currently off the coast of British Columbia, will dive southeast
from southern Saskatchewan into the eastern Dakotas Tuesday. This
system will have a lot of cold air aloft with very steep lapse
rates noted Tuesday afternoon. This will lead to an increased
threat for isolated showers, especially in the north and northeast
Tuesday afternoon. In addition to the threat of isolated showers,
strong NW winds will develop on the western and southwestern
periphery of the system Tuesday afternoon. Bufkit soundings this
morning, indicate high potential for mixing and inverted V type
soundings during the afternoon. In some cases, mixing occurs well
above 700MB and in some cases, it reaches above 600MB. Winds at
these levels is in the 40 to 50 KT range tomorrow afternoon. This
equates to gust potential of 40+MPH Tuesday afternoon. The strong
winds will lead to critical to near critical fire weather
conditions, which is highlighted below in the fire weather
section. Highs tomorrow will reach the upper 60s to lower 70s. The
latest GFS and NAM12 solns indicate a corridor of high H85 winds
from north central into south central and southeastern Nebraska
Tuesday evening with winds around 50 KTS noted. This will keep
wind speeds elevated through the evening hours.
.LONG TERM...(Wednesday through Monday)
Issued at 341 PM CDT Mon Apr 27 2020
Winds will shift around to the south from west to east Wednesday
afternoon. In the transition, winds will be fairly light across
western Nebraska. With minimum RH forecasted to be in the 15 to 20
percent range, the lighter winds will probably alleviate the need
for a red flag warning Wednesday. On Thursday, winds will
increase from the south as a surface trough of low pressure
deepens along the front ranges of Colorado and Wyoming. Minimum RH
falls off to 15 to 20 percent Thursday afternoon, and with winds
expected to be in the 15 to 25 MPH range Thursday afternoon, we
may end up needing some sort of fire headline if forecast trends
continue. Friday will be the warmest day of the period with
readings touching 90 in the far southwest. Fortunately, winds
will be light friday with a surface trough anchored across the
forecast area. The pattern aloft will begin to transition more to
west southwesterly aloft this weekend and remain in place through
Tuesday. This will make for a more active pattern across the area
with increased chances for precipitation and thunderstorms. The
latest GFS solution is indicating some meager moisture return to
the southwestern and western forecast area Sunday with H85 dew
points approaching 8-10C. A strong shortwave approaches the
central and northern plains Monday into Monday night. With the
degree of moisture return, and the strength of this shortwave in
the current model solution, this could be the first threat for
strong storms this season.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1053 PM CDT Mon Apr 27 2020
VFR conditions expected to persist through the forecast period. A
frontal boundary currently moving through the area will bring an
abrupt shift in winds to the west-northwest with gusts
approaching 25 knots. Sporadic gusts of 40 knots are possible but
confidence in occurrence at either terminal is too low to mention
at this time. Winds will increase quickly after sunrise on Tuesday
with gusts approaching 40 knots for north central Nebraska
including the VTN terminal. Elsewhere further south and west,
winds will be gusty but limited to around 30 knots or less. As
winds subside by late afternoon Tuesday, LLWS is expected to
develop and linger through the end of the forecast period.
&&
.FIRE WEATHER...
Issued at 341 PM CDT Mon Apr 27 2020
Very strong northwesterly winds of 20 to 30 MPH with frequent
gusts to 45 MPH are expected Tuesday afternoon. These winds will
be in association with a strong shortwave trough of low pressure,
which will slide across the eastern Dakotas into Iowa. Minimum
relative humidity tomorrow afternoon will reach 20 to 30 percent
across the forecast area. Realize these RH`s are above the
threshold for RFW criteria, however, given the strong winds and
fuels which are ready to burn (per conservations with fire
partners this morning), feel it prudent to hoist a RFW for
tomorrow afternoon into the early evening hours for all of the
forecast area. Minimum RH will be low each afternoon for
Wednesday, Thursday and Friday. Winds will be strongest on
Thursday in areas where the RH is closest to RFW criteria, so
Thursday afternoon has the best potential for a RFW given the way
the forecast stands right now. One final note, RH recovery is only
50 to 65 percent for Wednesday morning and Friday morning.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon CDT /11 AM MDT/ to 8 PM CDT /7 PM
MDT/ Tuesday for NEZ204-206-208>210-219.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Jurgensen
FIRE WEATHER...Buttler
Area Forecast Discussion
National Weather Service Topeka KS
549 PM CDT Mon Apr 27 2020
...AVIATION UPDATE...
.SHORT TERM...(This evening through Tuesday)
Issued at 338 PM CDT Mon Apr 27 2020
Weak disturbance that brought a few showers and thunderstorms to the
area this morning has slid off to the southeast, leaving clear skies
across northeast Kansas this afternoon. With the clear skies and
large scale subsidence in place, temperatures have warmed into the
mid and upper 70s. Continued southerly winds into tonight and some
early morning clouds will keep overnight lows in the mid 50s.
Heading into tomorrow, intensifying ridging over the West Coast will
cause a shortwave trough initially over Montana to quickly dive
southeast into the Plains, eventually carving out a rather deep
trough over the central CONUS. This digging shortwave will push a
cold front southeast across the region, passing through northeast
Kansas in the late morning and afternoon. This timing, along with
increasing moisture out ahead of the front, will favor the potential
for thunderstorm development during the mid-afternoon, though there
is still some uncertainty. The bulk of this uncertainty lies in the
possibility of some morning clouds and weak thunderstorms ahead of
the front, which may delay the main round of afternoon convection
until after the front has moved south of the area. However the
majority of short-term models do have enough heating ahead of the
front to develop storms by 2-3pm. With steep lapse rates of 7-8 C/km
aloft and moderate shear of 35-40 kts, large hail would be possible
with any storms. Damaging winds would also be possible given some
drier air in the lower levels resulting in higher DCAPE values. Any
tornado threat would be non-zero but would be limited by veering
winds and quick linear growth along the front. Given the likely
frontal position by mid-afternoon, places along and south of I-35
will be most likely to see severe weather, with storms moving south
and east of the area by early evening.
.LONG TERM...(Tuesday night through Monday)
Issued at 338 PM CDT Mon Apr 27 2020
After the initial cold front, a secondary vorticity maximum will
drop into the area Tuesday night, driving a secondary cold front
southeast again. Moisture will be limited with this, but very
favorable dynamics and some weak elevated instability may be enough
for a second round of showers and a few rumbles of thunder. Guidance
seems to be just starting to pick this up, but have increased PoPs
anyways given the favorable dynamics.
Wednesday into the start of the weekend, a period of dry and
increasingly warm weather will take hold as the strong western US
ridge shifts eastwards over the Plains. Temperatures by Friday and
Saturday should reach the 80s for most of the forecast area. By the
second half of the weekend, more zonal flow will set up across the
Plains as moisture gradually increases. With an east/west oriented
frontal boundary developing somewhere nearby, and several weak
disturbances moving through the zonal upper flow, shower and
thunderstorm chances will be present late Saturday into Monday.
Exact details are uncertain this far out, dependent on the exact
position and timing of various disturbances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday)
Issued at 549 PM CDT Mon Apr 27 2020
Biggest question is whether stratus develops ahead of the front
Tuesday morning. The NAM and GFS have been consistent in
saturating the boundary layer and the RAP suggests moisture will
be to shallow. Given a southerly low level wind has already set up
and there isn`t any dry air upstream to advect in, am leaning
towards stratus developing. Although confidence is marginal
because of the RAP soundings. So will keep CIGS MVFR for now, but
there is some potential CIGS could be lower than 1000 feet. Models
continue to show the better probs for TSRA development along the
front after it has passed the terminals. So will only include a
VCTS in the forecast for some possible post frontal showers and
storms in the afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Reese
LONG TERM...Reese
AVIATION...Wolters