Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/01/19
Area Forecast Discussion
National Weather Service Bismarck ND
1036 PM CDT Fri May 31 2019
.UPDATE...
Issued at 1031 PM CDT Fri May 31 2019
Just a quick update for temperatures. Overnight low temperatures
look reasonable as forecast lows are on the lower side of any
guidance, which seems reasonable given dewpoints in the mid and
upper 30s. But we adjusted the temperature curve as areas with
smoke have cooled quicker than other areas.
Some of the latest guidance regarding smoke is pointing more
toward southwest ND for greatest smoke concentrations, but all of
western and central ND will be affected.
UPDATE Issued at 915 PM CDT Fri May 31 2019
No significant changes from the previous forecast. Updated latest
sensible weather elements and blended to late evening values.
Updated sky cover based on latest satellite imagery.
Based on latest short range models it appears it could be a pretty
smoky day across western and central ND. Low level smoke
increases, especially northwest Saturday afternoon/evening. This
may lead to some visibilities down into the 3-5 mile range
Saturday afternoon/evening. Vertically integrated smoke shows the
entire column may be smoky. We had a couple days like this last
year where even though there were no or very few clouds, the sky
appeared cloudy due to the amount of smoke in the air. As
mentioned in the afternoon discussion, this may also affect
overnight lows tonight and daytime highs Saturday. A quiet weather
day Saturday, but with multiple forecast issues due to the smoke.
UPDATE Issued at 602 PM CDT Fri May 31 2019
Cold front has pushed through the forecast area. Convection across
western into northeast South Dakota is expected to remain south of
the state. Gusty north to northeast winds behind the cold front
area expected to diminish early this evening. It will remain quiet
through the night with hazy/smoky skies continuing.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 221 PM CDT Fri May 31 2019
Main challenge will be the affects of dense smoke aloft now over
northwest and north central ND, with the HRRR transferring this
southeast during the evening. Another more dense area is forecast
by the HRRR to shift into northwest ND this evening, and then
translate into central ND late tonight through Saturday.
Interesting we are seeing reflectivities per Minot Radar at 15kft
to 20kft as a tremendous amount of smoke particles are acting as
condensation nuclei with the moisture aloft per water vapor
imagery loop, to produce a substantial amount of high clouds.
These clouds are only forming in the area of smoke which extends
into northern Montana and then across western Saskatchewan and
Alberta. Outside of the smoke, we are literally cloud free.
Gridded model data is not able to pick this up, thus most of the
temperature and sky grids have been hand edited over forecast
builder at least through this evening. It is entirely possible
that tonight and Saturday we may observe a mostly overcast sky due
to the smoke aloft which will affect low temperatures tonight and
high temperatures Saturday.
Latest surface map and observations indicate the cold front is
just south of the border with cold air advection ensuing behind
the front via north-northeasterly winds. The CAM`s still show some
potential of a stray shower/thunderstorms grazing Dickey County,
but for the most part, the showers and thunderstorms will remain
south of the border, along and ahead of the cold front.
As mentioned above, visible imagery loop and HRRR Vertically
Integrated Smoke both show a swath of smoke aloft across northern
North Dakota, with even more upstream in western Saskatchewan and
through most of Alberta. With northwest flow aloft tonight,
Saturday, and into early Sunday, the trajectory of this smoke
aloft is right into northwest and into most of central North
Dakota. Not seeing much in the way of surface visibilities being
affected at this time, but think smoke aloft will have an effect
on high temperatures Saturday as full sunshine will likely be
limited due to the smoke. At this time, not sure how much cooling
will occur. For now, will go with lows tonight from 39F to 44F and
Highs Saturday in the low to mid 70s. Be prepared for upper 50s
to mid 60s if smoke is dense enough aloft.
.LONG TERM...(Saturday night through Friday)
Issued at 221 PM CDT Fri May 31 2019
Warm air advection returns Sunday with a chance of showers and
thunderstorms Sunday night west, otherwise, expect dry conditions.
Highs Sunday will range from 75F to 85F.
Monday through Friday...a zonal flow for most of this period,
then becoming more southwesterly Friday and into the upcoming
weekend as the GFS and EC show a deeper low/trough digging into
the intermountain west. Periodic shortwaves will lead to some
chances of showers/thunderstorms each day, but not seeing much in
the way for severe weather at this time. With a deeper moisture
fetch Friday and into the weekend along with stronger fronts,
perhaps better prospects for some severe thunderstorms might favor
this time period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1031 PM CDT Fri May 31 2019
Main forecast issue for the 00Z TAF forecast will be potential
visibility restrictions due to smoke. North to northeast winds
will diminish early this evening, then light and variable late
evening through mid morning Saturday, then west to northwest
Saturday afternoon, possibly up to around 12 knots at KJMS but
generally under 10 knots elsewhere.
Short term models point to increasing smoke over western and
central North Dakota on Saturday. Although skies will be mostly
clear, did keep a scattered layer around 7k feet Saturday, for
possible cu, but mainly smoke. Radar reflectivities picking up on
the smoke this afternoon and scattered layer indicated at Watford
City ASOS this afternoon. This west to east smoke layer drops
south overnight and models have it slowly dissipating. Smoke will
then increase again Saturday from the west. Near surface smoke
increases quite a bit over western ND Saturday afternoon, and may
linger into the evening. This is a little too far out to include a
reduction in visibility due to smoke in the TAF at this time, but
certainly something to monitor.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...KS
LONG TERM...KS
AVIATION...TWH
Area Forecast Discussion
National Weather Service Goodland KS
629 PM MDT Fri May 31 2019
.SHORT TERM...(Today through Saturday night)
Issued at 112 PM MDT Fri May 31 2019
Today-Tonight: A weak upper level low situated invof the Black
Hills will progress E-ESE through southern SD (this aft/eve) to
the SD/NE/IA border (tonight) as an upper level ridge amplifies
over the southern/central Rockies and High Plains. Synoptic
subsidence, a baggy low-level height/mslp pattern, weak low-level
flow (per KGLD velocity data and 18Z SPC mesoanalysis), and
marginal diurnal destabilization (250-500 J/kg mlcape) suggest
that in-situ convection is unlikely this aft/eve -- though isold
activity developing over the CO Foothills/Palmer Divide may
propogate downstream into Yuma/Dundy/Cheyenne counties (via weak
westerly steering flow) in the 21-03Z time-frame -- which is in
line with HRRR and NAM Nest simulated reflectivity forecasts.
Regardless, convection is anticipated to rapidly weaken/dissipate
with loss of insolation AOA sunset. Dry conditions will prevail
overnight.
Sat-Sat night: Modest WNW-NW flow aloft will prevail in this
period, on the E-NE periphery of an upper level ridge situated
over central/southern portions of the Rockies/High Plains. Low-
level southerly return flow on the eastern periphery of a broad
surface trough in the lee of the Rockies -- and the western
periphery of an H85 ridge along the central Gulf Coast -- will
advect low-level moisture northward from the western GOMEX into
the High Plains late Sat-Sat night. With upstream convection
anticipated in TX, the northern extent/quality of moisture return
into southeast CO and southwest KS remains uncertain, particularly
in such a weak low-level height/mslp pattern. At this time, expect
that scattered diurnal convection over the CO Foothills/Palmer
Divide will propogate downstream into western Kansas via WNW flow
aloft during the late afternoon and evening -- perhaps aided by
weak low-level upslope flow along/north of I-70 after ~00Z.
Although deep-layer shear will be sufficient for supercells,
marginal instability and weak synoptic forcing are likely to
temper the potential for severe weather -- particularly with
eastward extent into western KS where loss of insolation/
increasing CINH will further hinder convection.
.LONG TERM...(Sunday through Friday)
Issued at 208 PM MDT Fri May 31 2019
The extended forecast starts off with an upper low over California and
Nevada, a weak upper ridge over the Central High Plains, and
southwest flow aloft over the Four Corners region. Through the
day, the upper ridge will build over the region and temperatures
are expected to rise into the mid to upper 70s. A few showers and
thunderstorms will be possible as a shortwave trough moves through
the region. Monday will bring another chance for some moisture as
another shortwave trough moves through the area. Confidence in
coverage is not great at this time.
The upper low will gradually diminish into an open wave through Tuesday.
The trough will progress eastward, south of the Four Corners
region on Wednesday. The trough will continue through the Plains,
through southern Kansas and northern Oklahoma. Showers and
thunderstorms will be possible as this system moves through the
region on Wednesday and Thursday.
After a brief cooldown into the mid-70s to low 80s on Wednesday
and Thursday, temperatures will return to the low to mid-80s on
Friday as an amplified ridge sets up over the eastern CONUS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 628 PM MDT Fri May 31 2019
Throughout the remainder of the TAF period, VFR Conditions are
expected to prevail throughout the remainder of the TAF period.
There is a chance for some showers and storms to develop and
impact the terminals tomorrow afternoon, but confidence was too
low at this time to include.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...VINCENT
LONG TERM...AW
AVIATION...EV
Area Forecast Discussion
National Weather Service Grand Rapids MI
1054 PM EDT Fri May 31 2019
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 1054 PM EDT Fri May 31 2019
-Severe threat diminishing with outflow boundary running out ahead
of the storms
-Severe weather possible throughout the day Saturday as multiple
bands of storms move through the area
-Cold front makes way into the area Sunday bringing substantially
cooler and dry air
&&
.UPDATE...
Issued at 1054 PM EDT Fri May 31 2019
The general thinking as that the ongoing convection will gradually
weaken as it continues to drop southward tonight. All of the
convection allowing models show a similar diminishing trend. That
said, the RAP model does show MUCAPE increasing tonight to around
1500 j/kg. No good reason this should occur however and the
NAMnest shows a decreasing MUCAPE trend. Bottom line, we cannot
rule out an isolated shower or storm possible through the night.
In terms of any further severe threat it looks fairly minimal as
88D data shows the outflow boundary propagating away from the
convection which should aid in the diminishing trend over time.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 318 PM EDT Fri May 31 2019
The primary focus is on chances for strong to severe thunderstorms
tonight and Saturday. Overall, the threat for any severe weather
is quite low tonight, but there is at least a small risk for gusty
winds and hail mainly near U.S. 10 after 8pm. The threat for
thunderstorms looks to be more of an issue for Saturday,
unfortunately, and a few strong to locally severe thunderstorms
are possible near and south of I-96.
Based on the 12z CAM guidance, we are largely unimpressed with our
chances for thunderstorms in general tonight, with the main threat
being confined to the U.S. 10 corridor and lakeshore areas north
of M-20. Any storms that do form in northeast Wisconsin and
northern Lake Michigan may tend to migrate toward the better sfc
based instability over east central Wisconsin. But a few storms
may manage to impact particularly the western stretches of the
U.S. 10 corridor and locations immediately SW of there. Since
these storms may be rooted above the stable marine layer they can
potentially survive the trip over the lake. Nevertheless we do not
expect this to be a significant event tonight.
Saturday looks to be more of an issue with thunderstorm coverage
and perhaps intensity as well. SPC HREF guidance is indicating
1000-1500 J/kg south of I-96 while raw ECMWF and GEM guidance is
suggesting 1500-2500 J/kg possible. Somewhat complicating matters
is the threat for morning convection in the 12z-15z timeframe that
could delay destabilization. Even so, the cold front is not poised
to move through until the evening, so there is still time to
destabilize. Bulk shear magnitudes will be borderline or even
suboptimal for a severe event, suggesting multicellular storm mode
and sufficient precipitation loading/downdrafts will be needed to
produce severe wind gusts. CAPE in the hail growth region looks
good so there is a risk for some large hail.
PWAT values in the 1.2"-1.4" range, while not off the charts, are
high enough to warrant a threat for some localized heavy rain in
areas that get repeated rounds of storms. HREF 24hr localized
probability matched mean precip amounts suggest there may be small
pockets of 1"-2" of rain especially south of I-96. Localized
ponding of water on roads may occur with these rain amounts.
After FROPA Saturday evening, our temperatures will tumble quite a
bit. We`re looking at highs struggling to get into the low to mid 60s
Sunday and Monday. In fact, interior central Lower MI may deal
with a late-season frost Monday morning with temperatures dipping
into the mid 30s potentially. The next risk for rain holds off
until Tuesday night and Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 821 PM EDT Fri May 31 2019
Three main aviation concerns the next 24 hours are, showers this
evening (which may contain gusty winds), fog overnight and
thunderstorms on Saturday.
The showers would impact the TAF sites between 03z and 06z as they
drift south through the area. There is the possibility of some
gusty winds to in excess of 30 knots if they directly impact a TAF
site. Given low confidence have VCSH wording in, but did not
include the gusty winds. Low chance for a few storms tonight as
well, but left this out of the TAFs.
Fog is possible again late tonight as winds will be light and
skies try to clear in the wake of the line of showers/storms. MVFR
fog would be a good bet, with IFR possible.
A couple of rounds of thunderstorms look possible on Saturday. The
first one appears to be from mid morning through mid afternoon
with another one possible towards evening. Included VCTS wording
in the TAFs from midday through mid afternoon.
&&
.MARINE...
Issued at 318 PM EDT Fri May 31 2019
Aside from thunderstorm hazards to mariners Saturday, we`ll be
watching for enhanced wind and wave action for Sunday that should
hold below SCA. High pressure moving in along with NW flow could
boost waves especially near and south of Muskegon during the day
Sunday.
&&
.HYDROLOGY...
Issued at 318 PM EDT Fri May 31 2019
The rivers near Vicksburg and Maple Rapids remain above bankfull,
with only low lying areas near the river under any water. No
significant river flooding is expected over the next several days.
There are several rounds of thunderstorms likely to affect our area
over the next day or two. These are expected to move through fairly
quickly, but if multiple thunderstorms happen to track over the same
areas repeatedly, bigger rainfall totals and local ponding of water
on roads is possible. Always slow down and drive carefully during
heavy rain, especially at night.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Duke
SYNOPSIS...Duke
DISCUSSION...Hoving
AVIATION...Duke
HYDROLOGY...AMD
MARINE...Hoving
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
928 PM CDT Fri May 31 2019
.UPDATE...
921 PM CDT
Main changes this evening were to delay shower/thunderstorm
chances tonight, thinking if any development were to move across
the CWA it would be closer to early Saturday morning. Still some
possibility for upstream development to the northwest and north
slide east southeast into the instability gradient later tonight
into Saturday morning. If this were to occur, then scattered
showers/thunderstorms would be possible over northern IL during
that time. If this doesn`t occur, still some possibility for
isolated development over eastern later tonight to work its way
into northern IL Saturday morning. So, did delay pops until after
midnight across the area, but still thinking chance wording is
worthy late tonight into Saturday morning. Will need to continue
to monitor for any possible development into Saturday, as this
will likely play a factor for later thunderstorm development on
Saturday. Although some uncertainty tonight into Saturday remains,
the threat for severe storms Saturday afternoon across the area
remains.
Rodriguez
&&
.SHORT TERM...
257 PM CDT
Through Saturday night...
Regional water vapor loops depict three shortwaves drifting
around the region, one (which initiated yesterday`s and last
night`s convection) peeling away to our south and east, one
drifting into South Dakota, and another shearing out across
Kansas/Nebraska as it enters strong confluent flow at the base of
an amplified shortwave ridge. Mid-level height rises today and a
lack of any appreciable surface forcing mechanisms will keep
things dry and mostly sunny (save for lingering smoke from
wildfires in Alberta overhead). Can`t rule out some storms
attempting to fire across parts of Iowa a bit later this afternoon
within a region of subtly-enhanced surface convergence. This
activity should dwindle quickly this evening as it tracks eastward
into increasing convective inhibition. We`ll continue to paint
some "silent" PoPs across our far west and some additional cloud
cover from any cirrus blow-off, but not expecting any impactful
weather through the mid-evening hours (and really through the
night).
Latest satellite loops show cumulus bubbling across northern
Wisconsin and central Minnesota along a southward-diving cold
front. Should see a gradual uptick in convection here through the
afternoon hours as this activity attempts to build southward. The
environment immediately ahead of this developing activity is
becoming modestly unstable with gradually weakening convective
inhibition. Latest runs of the HRRR have trended towards quickly
weakening any convection that attempt to materialize near this
frontal zone this evening. Do wonder if this is a tad optimistic,
although certainly don`t currently expect any robust convection
to survive the journey into Illinois. This is due to the
combination of veered (and weak) low-level flow and deep layer
shear vectors becoming more westerly this evening and overnight,
coupled with a lingering pocket of drier air in the 850-700 mb
layer/increasing inhibition. This would favor any potential
complex quickly exhausting an outflow and quickly weakening as it
approaches our region tonight. With this in mind, will continue to
depict a north-to-south tapering of (low) PoPs late this evening
and overnight with the highest chances near the WI/IL state line.
Overall think this activity will be mostly devoid of lightning
should it reach our region, but will indicate some lower thunder
coverage given the lingering steep 850-500 mb lapse rates in place
overhead.
The forecast for Saturday is fairly uncertain as several mesoscale
boundaries may be dancing around the region from any remnant
morning convection and these will likely play a role in modulating
the location of the main severe corridor and subsequent potential
for an isolated tornado threat.
The current thinking is that mainly elevated showers and some
embedded storms will be possible through the mid-morning and
early-afternoon hours as more defined isentropic upglide--
maximized along the 305 K theta surface--gets going. As this broad
ascent begins to intercept a plume of steeper mid-level lapse
rates and increased moisture content, would assume at least some
uptick in convective coverage from about 9 AM - 12 PM or so.
However, most hi-res guidance remains uninclined to produce much
in the way of precipitation during this period. Should elevated
convection get going, the steep lapse rate environment would
foster some propensity for updraft acceleration and allow for some
small hail potential. The overall severe threat through the
morning hours will be greatly tempered by a lack of more
appreciable mid-level flow with 500 mb winds generally under 25
kts.
Deep layer shear will begin to increase quickly during the early
afternoon hours as a shortwave--currently entering southwestern
South Dakota--pinwheels into the region. The environment ahead of
this feature and associated cold front will be characterized by
steep mid-level lapse rates (assuming a lack of widespread
convection during the morning), and moderate instability with
MLCAPE values building diurnally into the 1500-2500 J/kg range.
This environment will support the potential for organized severe
convection developing through the mid-afternoon hours. The initial
threat with any discrete activity will probably be from large hail
(ping pong ball to perhaps golf ball sized given the steep lapse
rates overhead), with a gradual transition to several broken
lines/clusters that would begin to deliver a greater severe wind
potential as activity tracks east of I-39. From a synoptic
standpoint the tornado threat is low in this set up with a lack of
more appreciable hodograph curvature. However, we will need to
closely monitor for the existence of any remnant outflows which
could locally enlarge low-level hodograph curvature during the
afternoon and into the evening hours. As it stands now, the main
time for a severe threat seems to be during the 2-8 PM window.
Activity should pretty quickly push south and east of the region
as this sharp shortwave will remain quite progressive. Locally
heavy rainfall will certainly be a concern, although the quick-
moving nature of this system should preclude a greater concern for
widespread flash flooding. Wouldn`t be surprised if there were
some isolated instances of flash flooding on Saturday (our soils
obviously simply cannot handle a great deal of water in a short
amount of time) with the latest HREF Probability Matched Mean QPF
product highlighting areas east and north of a Rockford to
Kankakee line for a potential for localized 1.5-2.5 inch amounts
before all is said and done.
Carlaw
&&
.LONG TERM...
306 PM CDT
Sunday through Friday...
The long term forecast period will be notable for a rare period of
dry weather, but it will be followed by another period of unsettled
weather.
Following the frontal passage that will bring Saturday`s activity,
there should be a period of dry weather from early Sunday morning
into Tuesday afternoon as a large area of sfc high pressure and
broad upper ridging build across the region. Given this synoptic
longwave pattern, confidence is relatively high that much of this
period will be dry. Still can`t completely rule out some isolated
light showers/sprinkles late Sunday night as a weak shortwave drops
across the region in fast northwest flow aloft. However, given a dry
sfc airmass moving across the area associated with the large area of
high pressure building in behind the front, do not expect that any
pcpn that might reach the ground should not be wetting or measurable
and have kept PoPs below mentionable. Temperatures should start out
the period a bit below normal for Sunday and Monday with highs
ranging from the upper 50s to lower 60s along the lake front to the
low 70s well inland. By Tuesday, the sfc high will settle through
the Ohio Valley to the sern Atlantic coast while another cold front
pushes into the Central Plains. This will set up a return flow of
warmer, more humid air in swly low-level flow. So, following a
period of almost 3 days with no measurable rainfall, conditions
should become more active again from Tuesday night through Friday
and possibly, into next weekend.
For the remainder of the long term forecast period, temperatures
will trend back to more seasonable levels, with highs, generally, in
the upper 70s to low 80s. The warmer air should reach up to the
lakefront through Wednesday as surface winds will be predominantly
southwesterly and strong enough to prevent lake breeze formation.
The long range guidance continues to suggest that another extended
period of unsettled weather could begin by as early as late Tuesday
night into Wednesday as scattered showers and thunderstorms develop
in advance of the next approaching sfc cold front, with moderate
warm advection/isentropic lift coincident with a series of
shortwaves ejecting newd out of the South High Plains ahead of a
deep upper low digging into the Desert Southwest. The global
models remain in relatively good agreement on pushing the cold front
across the area early Wednesday. Not only will this signal the
beginning of the next period of active weather, winds will also
shift to more northeasterly, bringing cooler conditions back to the
lakefront. The longer range guidance continues to indicate that the
frontal boundary could stall out somewhere just south of the CWA. A
stalled front to the south along with a continued series of
shortwaves lifting out of the South High Plains, should bring
periods of showers and thunderstorms through late next week and
possibly into next weekend.
&&
.AVIATION...
For the 00Z TAFs...
VFR conditions with west winds are expected through daybreak
Saturday at all sites. Rather isolated -SHRA will be possible late
tonight as convection currently over northern WI decays while
shifting south. If this convection were to continue farther south
than expected, -SHRA coverage would be more. Additionally, outflow
from this convection would likely shift far enough south to allow
for a few hours of N/NE winds prior to 12Z before SW/W winds resume
Friday morning.
Confidence on the forecast beyond late Friday morning decreases as
it will depend on the continued SW extent and possible lake-
enhancement of the aforementioned outflow boundary. Gusty SW/W winds
developing through the morning away from the outflow should suppress
any considerable SW expansion during the morning hours. But there is
a chance that the lake-enhanced outflow boundary will still reach
ORD/MDW by 16-18Z Friday. Given this low of confidence, have left
the mention of it out of the TAF at this point. For the afternoon
hours, two scenarios appear nearly equally possible:
1) The outflow passes through the Chicago metro, shifts winds NE,
and initiates TS W and S of the terminals during the early to mid-
afternoon, with some convection directly affecting the terminals for
a period.
2) The outflow remains E of the terminals, winds gust to possibly
over 20 kts from the WSW, strong TS develops just west or over the
terminals by 20z.
As noted before, each scenario remains plausible. Which one occurs
will likely remain unclear until upstream convective trends are
more evident later tonight.
Kluber
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
739 PM EDT Fri May 31 2019
.SHORT TERM...(This evening through Saturday)
Issued at 426 PM EDT FRI MAY 31 2019
WV imagery and RAP analysis indicated wnw mid/upper level flow
through the northern Great Lakes on the periphery of a mid level
trough from northern Manitoba through northern Quebec. At the
surface, weak low pressure was located over west central Upper
Michigan. A cold front boosted by the lake breeze from Lake Superior
was also sagging south through western Upper Michigan while deep
mixing to the south of the front has pushed temps into the mid 80s.
Even with dewpoints only in the low to mid 50s from n cntrl Wi into
south central Upper Michigan, MLCAPE values had climbed into the 500-
1000 J/Kg range.
Scattered shra/tsra have developed in north central WI into IMT/MNM
in the area of strongest low level convergence near the MLCAPE
gradient. Mainly unidirectional 0-6km bulk shear to around 45 knots
will support some isold strong to possibly svr storms. With DCAPE
values to around 1k J/Kg both marginally svr hail and damaging gusts
will be possible into this evening for locations south of US-2.
Late this evening and overnight, as the front moves farther south,
any lingering shra/tsra may still brush the far south near MNM.
Otherwise, dry conditions are expected with temps dropping to around
40 north and the mid 40s south.
Saturday, models suggest that the combination of of a northern
stream shortwave moving out of srn Saskatchewan and a shrtwv over
wrn SD will bring another area pcpn through cntrl WI that could brush
the far south with additional rainfall amounts of around a tenth of
an inch. Otherwise, weak nrly flow and lake breezes will keep temps
in the 50s near Lake Superior with 60s farther inland under partly
to mostly cloudy skies.
.LONG TERM...(Saturday night through Friday)
Issued at 423 PM EDT FRI MAY 31 2019
Shortwave rotating through Saturday night looks to help trigger off
some shower activity, primarily in the south-central where moisture
availability is a smidge better. As it traverses across, some
showers could be sparked in the eastern U.P. as well but all of
these chances look rather low overall. Surface high pressure then
moves in on Sunday, allowing for benign weather to prevail.
Overnight Sunday into Monday, could see some additional shower
chances across the southwest into the south-central U.P., courtesy
of a jet streak moving overhead and leaving the area within the
right entrance region. This activity will be riding along the
periphery of an upper-level ridge, with what looks to be a bit more
moisture available to work with as compared to earlier in the
weekend. Upper Michigan should remain on the periphery of the ridge
as it keeps its hold over the SE U.S., leaving the door open for
more widespread showers and thunderstorms Tuesday into Tuesday
night. Following this disturbance, could see surface high pressure
moving in again, but with model solutions rather divergent from this
timeframe onward, low confidence in this. Tis the season for more
sporadic shower/thunderstorm activity, better resolved in the nearer-
term.
Although there will be some waffling of temperatures throughout this
forecast period, overall, near normal highs/lows are anticipated.
Sunday looks to be the coolest day of next week, with a general
warming trend from Monday onward. Currently, frost doesn`t appear to
be a big concern.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 739 PM EDT FRI MAY 31 2019
With low-levels remaining relatively dry, VFR conditions will
prevail thru this fcst period at KIWD/KCMX/KSAW. Winds will be under
10kt tonight and Sat.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 426 PM EDT FRI MAY 31 2019
A cold front dropping through Lake Superior will bring a period of
northwest winds into the 20-25 knot range Sunday over eastern Lake
Superior. Otherwise, winds will remain at or below 20 knots into mid
week next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...lg
AVIATION...Rolfson
MARINE...JLB
Area Forecast Discussion
National Weather Service San Francisco Bay Area
855 PM PDT Fri May 31 2019
.SYNOPSIS...Isolated afternoon showers and thunderstorms will be
possible over the southern Diablo Range through Sunday as an upper
level low persists over central and southern California.
Otherwise, look for areas of night and morning low clouds through
the weekend, with temperatures near seasonal averages. A warming
trend is then forecast on Monday and Tuesday of next week as a
ridge of high pressure builds over California. This brief warmup
will likely be followed by cooling during the second half of next
week.
&&
.DISCUSSION...As of 8:55 PM PDT Friday...An upper low centered
over central California triggered scattered showers and thunderstorms
over the Sierra Nevada and southern Diablo Range this afternoon.
In our area, most of the afternoon convection developed over
southern San Benito County and far southeast Monterey County.
Several afternoon lightning strikes were detected in these areas
and as much as 0.21" of rain fell. One brief shower also
developed over extreme eastern Santa Clara County. Radar shows
that lingering showers in these remote rural sectors of our
forecast area are quickly dissipating as surface heating ends.
The upper low is forecast to drift very slowly south into
southern California through the weekend. The 00Z NAM indicates
that moisture and instability associated with the low will
continue to result in isolated afternoon and evening thunderstorms
through the weekend in the same general areas where convection
occurred today. The latest HRRR also points to the possibility of
isolated showers or thunderstorms across the northern edge of the
North Bay tomorrow afternoon.
The bulk of our forecast area, including all major population
centers, are not expected to be impacted by afternoon and evening
convection this weekend, and are forecast to remain dry except
perhaps for patchy night and morning drizzle from the marine layer.
Temperatures are expected to remain near seasonal averages
through the weekend. The marine layer, currently at a depth of
about 1500 feet at Fort Ord, will likely persist near its current
depth.
A warming trend is forecast to get underway on Monday as the
upper low drops into far southern California and as an upper ridge
over the eastern Pacific begins to nose across northern
California. Most models indicate shower/thunderstorm chances will
end across our area by Monday. Warming will continue into Tuesday
as the ridge becomes established over California. Inland areas
will see the most robust warming on Monday and Tuesday, while
coastal areas experience limited warming due to persistent onshore
flow. Some of the warmest inland valleys are forecast to warm
into the lower 90s by Tuesday. The warming trend will likely come
to an end by Wednesday when the upper ridge axis is forecast to
move to our east and onshore flow begins to increase. Cooling is
then expected on Thursday and Friday as an upper trough moves
through the Pacific Northwest and northern California.
Precipitation with the trough is expected to remain well to our
north. In the longer range, both the GFS and ECMWF indicate
renewed ridging in time for a warm up over the weekend of June 8
and 9.
&&
.AVIATION...as of 4:38 PM PDT Friday...for 00Z Saturday TAFs. VFR
conditions are forecast to prevail at the San Francisco Bay Area
terminals this late afternoon and evening before transitioning to
MVFR/IFR ceilings overnight. Visible satellite already shows the
marine stratus along the immediate Pacific pushing through the
Golden Gate. Additionally, the stratus is just beginning to impact
Monterey Bay Area terminals with SCT to BKN observations. The
onshore gradients aren`t as strong this afternoon compared to 24
hours ago, so don`t think the return will be as early for the SF
Bay Area terminals. The onshore winds will subside after sunset.
Vicinity of KSFO...VFR conditions for the remainder of the
afternoon and evening, then MVFR/IFR ceilings return overnight.
Breezy west winds this evening around 20 kt will subside after
sunset and become light as the night progresses.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Ceilings are starting to return to both
MRY and SNS, thus MVFR/IFR conditions are forecast this evening
and overnight. Onshore winds around 10-15 kt will subside after
sunset.
&&
.MARINE...As of 8:26 PM PDT Friday...Light to locally moderate
northwest winds will prevail overnight and into the weekend as
high pressure remains over the eastern Pacific. The strongest
winds are forecast to be generally north of Pigeon Point. Winds
will then become south to southwesterly along the immediate coast
on Sunday afternoon. Waters with locally breezy and gusty winds
will likely experience steep fresh swell. A smaller long period
southerly swell will be more evident in south-facing sheltered
bays.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: Rowe
MARINE: Rowe
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Area Forecast Discussion
National Weather Service Riverton WY
250 PM MDT Fri May 31 2019
.SHORT TERM...Tonight through Monday
We currently have a scattering of showers and thunderstorms going on
across portions of western and central Wyoming. They did fire a bit
earlier than I thought earlier though. Coverage is greater than
yesterday given the extra kick of a weak shortwave that is moving
southward through the area out of Montana. So far, most of the
storms are behaving themselves. With the weak steering flow though
they are slow movers and could but down a brief heavy amount of
rain. We haven`t had any problems with this yet but it will have to
be monitored. Given the extra kick from the shortwave, we have
lingered some thunderstorms into the overnight hours. However,
coverage is expected to decrease after around 9 pm with the loss of
daytime heating.
We should see somewhat of a decrease in coverage on Saturday as some
ridging builds northward across the area and increases heights
across the area. There will still be a some around, but at this
point they look to more diurnally driven so we confined them to the
afternoon and evening hours. I can`t rule something out a bit
earlier, but this would be the exception rather than the rule. All
areas will have at least isolated showers or storms in the area
through. Many areas will remain dry though. Temperatures will also
continue a slow upward trend with many of the lower elevations
climbing into the 70s once again. Any storms that do form will
likely again be slow movers due to the continued weak steering flow.
Temperatures will continue to warm Sunday as well. With heights
continuing to build across the area, this looks to be the minimum in
storm coverage of the three days. All the models have trended a but
drier on Sunday so we made more areas largely dry. The best chance
of any storms would again be near the mountains and adjacent
foothills and with light steering flow will likely not move anywhere
quickly.
There is a bit more uncertainty for Monday. A trough will begin to
approach the area from the west. There are some differences in
timing however. For now, we have shown an increase in coverage of
showers and storms across western and northern Wyoming. Temperatures
will also continue to rise with some areas east of the Divide
possibly cracking the 80 degree mark for the first time this year.
.LONG TERM...Monday night through Friday
Afternoon showers and thunderstorms Monday look to continue into the
evening hours as a weak shortwave trough moves eastward across the
MT/WY border from 00z-12z Tuesday. With high pressure to the
southeast over the south central Plains and a larger trough over the
Desert Southwest, warm moist air should be brought up from the south
into the area. The pattern is similar on Tuesday except that more
zonal flow across the northern states will continue with a weak
boundary moving southward east of the divide. More showers and
thunderstorms are expected Tuesday afternoon and evening, mostly
over NW WY and along the boundary through central WY. The large
scale pattern looks to start shifting Wednesday into Friday as a
large-scale trough moves into the Pacific Northwest with high
pressure more over Arizona and New Mexico. Wednesday is expected to
have more showers and thunderstorms across the northern part of the
state as temperatures climb a few more degrees to the mid 70s to low
80s. Thursday should see stronger mid-level southwest flow move into
the western part of the state. At this time, it appears a weak
shortwave trough may enhance convective activity across NW WY
Thursday afternoon and evening, though it is certainly too far out
to nail that down. The large-scale trough moves eastward on Friday,
and with a decent lee-side surface low developing in NE WY Friday
afternoon, southwest flow will become stronger across much of the
forecast area. GFS is more progressive with the trough and
resulting front compared to the ECMWF, which digs it more into the
Intermountain West and delays the front by about 24 hours. This
overall pattern is much more typical of June weather across the
forecast area, so will have to monitor more closely in the short-
term for stronger storms and heavier showers.
&&
.AVIATION...00Z Issuance
Scattered showers and thunderstorms will continue from 21z/Fri to
about 03z/Sat, with residual showers possible until after 06z/Sat.
NAM runs today though have indicated possible broader area of
showers from KBPI eastward to KCPR from 03z to 09z/Sat. HRRR is
now corroborating area of showers moving from west-central into
central WY after midnight. General VFR conditions expected during
the forecast period, though MVFR likely under and around showers
and thunderstorms. Some storms have produced gusty outflow up to
30 kts, and this can be expected through 03z/Sat as well. Partly
cloudy skies to remain overnight. Scattered showers and
thunderstorms are expected again on Saturday with development
starting between 18z to 21z/Sat primarily over the higher terrain
in southerly mid-level flow. Convective activity should increase
over western WY between 21z/Sat and 03z/Sun before tapering off.
&&
.FIRE WEATHER...
A weak weather system will bring isolated to scattered showers and
thunderstorms to the area into the overnight hours, although
coverage will decrease after sunset. Isolated to widely scattered
mainly afternoon and evening showers and thunderstorms are also
possible into the weekend, although with less coverage. Gusty winds
in Johnson County should decrease this evening. Light to moderate
winds are expected this weekend except near showers and
thunderstorms. Relative humidity should remain above critical
levels. Mixing and smoke dispersal will be generally fair to good on
Saturday.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Hattings
LONG TERM...McDonald
AVIATION...McDonald
FIRE WEATHER...Hattings
Area Forecast Discussion
National Weather Service Blacksburg VA
1101 PM EDT Fri May 31 2019
.SYNOPSIS...
An upper level trough will shift east of the area tonight with
storms ending. This disturbance will move off the coast
Saturday. A cold front will sweep through the region Sunday with
another chance for storms, followed by a change in airmass to a
cooler one for early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1100 PM EDT Friday...
Made some adjustments in temperatures utilizing the latest
surface obs, their trends and blended in the NBM for tonight
into Saturday morning. Decreased pops for late tonight into
Saturday morning, shaping towards HRRR and Hiresw-arw-east.
Added some patchy fog.
As of 815 PM EDT Friday...
Severe Thunderstorm Watch 300 is now cleared in its entirety.
Severe threat has de-escalated to this point, though still a few
sub-severe thunderstorms moving across northern Pittsylvania and
Halifax and Charlotte Counties through 9 PM. A few
residual/rogue showers still possible in the mountains as the
upper low pivots through but thunderstorm threat west of the
Piedmont has ended. Refreshed the grids with the cancellation of
the Watch, re- shaping Wx grids and removing enhanced
wording/severe mention.
Previous valid discussion...
As of 330 PM EDT Friday...
The upper trough moves overhead by midnight with main batch of
storms heading east of our area during this time, so will see
pops lowering from west to east overnight. With residual
moisture and upper trough axis lingering, a few showers may
stick around even into the late night and early morning hours
Saturday. Fog in the mountain valleys may become a concern late
tonight if any clearing takes place.
Once the trough clears the area Saturday, we will be in between
upper level systems and lack any dynamic kicker for organized
showers/storms. That said, moist boundary layer and daytime
heating may lead to isolated popup showers Saturday afternoon,
favoring the mountains.
Temperatures through Saturday are expected to remain relatively
mild with lows in the U50s to L60s, and highs in the 70s to
lower 80s.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 300 PM EDT Friday...
Any convection Saturday afternoon will fade with lose of heating in
the evening. An area of weak high pressure will edge into the
mountains from the southwest while a lee trough resides over the
piedmont. On Sunday, a cold front will slide across the region and
may jump to the lee trough in the afternoon. Overnight surface
ridging and winds turning quickly to the west will provide some
stability, therefore not looking at a large scale severe threat over
the area. The 12Z GFS/ECM models fire convection over the coastal
piedmont of VA/NC late in the day as the front jumps to the lee
trough, but that is well to our east. On the other hand, NAM and
associated convective models track scattered strong storms across
the foothills and piedmont through the afternoon. Took a blend of
models and kept at least chance PoPs during the day Sunday.
On the back side of the front, models are also showing upslope rain
shower overnight Sunday. Upslope shower typically do not materialize
in the warm season, but will likely see low clouds and/or drizzle
develop. For now, will carry slight chance PoPs for western slopes
Sunday night.
Dry cold high pressure will move from the Ohio Valley Sunday night
and Monday to over the region Monday night. While this high sits
over the Ohio Valley, a tight pressure gradient will bring breezy
conditions to ridgetops Sunday night. As the inversion breaks
Monday, breezy and gusty winds are expected over the entire area.
Winds 15-20 MPH with higher gusts will be common, especially west of
the Blue Ridge. Winds will diminish as high pressure settles over
the region Monday night.
Temperatures will run slightly warmer than normal on Sunday with
readings in the 70s west and low to mid 80s east. On Monday,
temperatures will average below normal with highs across the
mountains in the upper 60s to lower 70s and upper 70s east of the
Blue Ridge. With decreasing winds Monday night, lows will range from
the upper 40s west to mid 50s east.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 300 PM EDT Friday...
Surface high pressure moves off the VA/NC coast on Tuesday.
Meanwhile, another upper level ridge builds over the Gulf. With the
placement of the upper level ridge, we will need to keep an eye over
the Ohio Valley as disturbance track along the ring of fire and
towards the region. At this time, Wednesday and Thursday afternoon
look active.
Temperatures will moderate warmer than normal through the end of the
workweek.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 730 PM EDT Friday...
Severe Thunderstorm Watch #300 remains in effect until 03Z/11PM
this evening for TAF sites east of the Blue Ridge..KDAN and KLYH
but even that will only be for a few more hours. Convective
trends show all of the severe activity east of the mountains
and even KLYH not likely to experience a storm at the terminal
but close enough for VCTS.
The short-wave trough and stronger winds aloft will shift east
of the terminals by later this evening and only a few widely
scattered showers remaining and mainly dissipating by midnight.
Patchy fog possible by morning where rain showers were heavier.
Partial clearing is expected Saturday with a return to VFR for
the afternoon. Another front will cross the forecast area Sunday
with the potential for another round of showers and
thunderstorms associated with the frontal passage.
Extended Aviation Discussion...
Passage of a surface front Sunday will introduce a cooler drier
airmass for Monday and Tuesday. Primary flight category VFR.
Unsettled conditions are expected to return for the second half
of the week with the return of moisture and moderating
temperatures.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...AL/KK
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...PC/PM