Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/20/22
Area Forecast Discussion
National Weather Service La Crosse WI
648 PM CDT Thu May 19 2022
.DISCUSSION...(This evening through Thursday)
Issued at 254 PM CDT Thu May 19 2022
- Severe weather expected this afternoon and evening
- Frost/Freeze Headlines Maybe Needed Sunday Night
Late This Afternoon and Evening...
Continuing to monitor the northward progression of a warm front
which extends from Albert Lea, MN to Platteville, WI. Temperatures
south of this warm front range from the mid-80s to lower 90s. Dew
points have dropped into the 50s in the wake of this mornings
convection. Further to the southwest, the dew points range from
the mid-60s to lower 70s. There is still some questions how much
moisture recovery there will be in the warm sector. The latest
HRRR has a good handle on the current dew points and it shows that
the dew points will recover into the lower 60s. Until that
moisture gets back into the area, there may be a lull in
convection in this area. Soundings show an inverted V in this
area, so there will be a threat of damaging winds and large hail
once the convection returns to this area between 5 PM and 7 PM.
Meanwhile, along the warm front, VWP is showing backing winds at
KLSE and this lengthening the 0-3 km hodograph. The RAP and HRRR
indicate helicities increasing into the 300 to 400. The 0-1 km
computed CAPES will likely climb into the 800 to 1200 J/kg range.
The highest values look to be from the Iowa/Minnesota boarder
north into southeast Minnesota and maybe the counties bordering
the Mississippi in Wisconsin. This tornado threat looks to be from
4 PM to 7 PM.
As the cold front approaches and the moves into the narrow ribbon
of return moisture, there will a line of storms developing along
the cold front. These storms will be capable of producing large
hail and damaging winds. There is still some uncertainty on how
far south the storms will develop into the warm sector.
Sunday through Thursday...
Precipitation chances continue into Sunday morning as an upper level
trough moves over the area. As the trough lifts out of the area,
precipitation could linger over our northern counties into early
Sunday afternoon. High temperatures will remain in the upper 50s/low
60s during the day, and with clouds moving out overnight, low
temperatures could drop down to the low/mid 30s for some.
Frost/freeze headlines may be needed Monday morning.
Although the end of the weekend into Monday appears to be dry,
increasing chances for precipitation returns through the week. While
ensemble solutions show increasing agreement on upper level
troughing moving across the area midweek, there are differences in
the progression of the trough. With this disagreement, differences
in the timing and coverage of precipitation across the area remains.
Temperatures will return to the low/mid 60s for the start of the
week. However, EPS solutions suggest an upward trend in
temperatures into the weekend, with ensemble means above model
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 647 PM CDT Thu May 19 2022
A line of showers and storms over KRST will slowly sag into KLSE
between 20.01Z and 20.02z. Ceilings will range between 5 and 10K
feet. A few of the thunderstorms may become severe. Damaging winds
and hail are the main concerns. Visibilities at times may become
IFR/MVFR this evening in some places, but confidence was not high
enough to include them in the TAFs at this time.
The thunderstorms will gradually come to an end between
20.05z and 20.07z. While the thunderstorms will be ending
scattered showers will continue for much of the remainder of the
Area Forecast Discussion
National Weather Service Columbia SC
808 PM EDT Thu May 19 2022
Warming trend continues through the end of the week with
temperatures well above average. Isolated thunderstorms mainly
across the northern Midlands this afternoon and evening, with
isolated severe weather possible. Better rain chances return
this weekend as a frontal boundary moves into the region.
.NEAR TERM /THROUGH TONIGHT/...
Showers and storms have stayed well away from our cwa this
evening, and expecting a dry period overnight. Latest hrrr shows
no activity through the night, with the nearest showers
remaining closer to the NC/VA border. Skies will remain mostly
clear with only some thin cirrus moving through. Winds not
expected to go calm, but should drop off to around 5 knots. With
the winds, do not expect fog. Expect overnight lows in the
upper 60s to around 70 degrees.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Rising heights and dry air intrusion Friday with PWATs dropping
to around 1.1 to 1.2 inches. Temperatures likely a degree or
two warmer across the area with the exception of the CSRA where
a bit of high clouds will push in during the afternoon but
otherwise expect mostly sunny skies. Highs once again in the mid
to upper 90s. Moisture begins to return Friday night as the
ridge axis shifts offshore and deep southerly flow returns to
the forecast area. Temperatures overnight remain mild with lows
around 70 as clouds increase in coverage.
A shortwave will push through a weakness in the ridge Saturday
with showers and storms possible especially in the afternoon,
with highest chances in the CSRA. While forcing from the
shortwave will make coverage highest in the CSRA, diurnal storms
will still be possible elsewhere as we head into a more summer-
like pattern. Weak shear expected limiting the severe threat
although some dry air may enhance downdrafts. With increased
cloudiness as well as higher chances for precipitation,
temperatures will be lower although with at least some weak
ridging in place, still expect temperatures above average in the
low to mid 90s. Another mild night Saturday night with lows in
the upper 60s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A warm, moist pattern is expected to persist through the long
term period with additional forcing provided by an approaching
cold front into early next week. Ensembles indicate PWATs will
remain above the 90th percentile, with most members remaining
above 1.5 inches through the extended period. This will continue
to support an unsettled pattern, further enhanced by the
approaching front which will likely stall near the area.
Generally storms will continue to be diurnally driven with
limited chances for severe weather. Blended guidance continues
to support temperatures near average in the long term, trending
away from cooler conditions of previous runs and the current
forecast reflects that.
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR conditions likely through the 24 hour TAF period.
Convection over the Appalachians and along the sea breeze has
struggled to develop so showers and thunderstorms should not impact
the TAF sites this evening. Relatively dry air and a 30kt LLJ should
prevent widespread fog or stratus overnight. The HRRR keeps a
stratus deck south of the forecast area where moisture is deeper,
adding confidence to a VFR forecast. Upper ridging and limited
atmospheric moisture will prevent moist convection on Friday leading
to a dry forecast. Winds will pick up around or shortly after 15Z
out of the SW around 10 kts with gusts up to 20 kts.
EXTENDED AVIATION OUTLOOK...This weekend: showers and thunderstorms,
mainly in the afternoon and fog and/or stratus possible each
morning. This pattern persists into early next week.
Area Forecast Discussion
National Weather Service State College PA
1118 PM EDT Thu May 19 2022
Fair and mild conditions will prevail tonight with areas of fog
forming after midnight. Hot and humid weather arrives for
Friday afternoon and will continue through much of the upcoming
weekend. This will feature the hottest weather since last summer
to central PA with record challenging/breaking temperatures
Friday into the weekend.
A cluster of showers and thunderstorms could dampen the
morning and midday hours Friday, mainly across the southern half
of Pennsylvania, as they moves east from the Ohio River Valley.
Otherwise, isolated afternoon and evening thunderstorms are
possible Friday and Saturday. Showers and thunderstorms are most
likely on Sunday as a strong cold front moves across the
Commonwealth. Conditions dry out to start next week with
noticeably cooler temperatures and much lower humidity.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A few clusters of thunderstorms continue across the Ohio Valley
this evening. The initial MCS, currently over southern Ohio,
should arrive in our CWA between 8z-11z. It will most likely
weaken to just showers or low clouds given that it will travel
down a steep gradient in CAPE. Therefore we aren`t expecting
thunderstorms before daybreak, but showers are possible in the
Comfortable conditions prevailing this evening thanks to
advection of lower dewpoints all the way into the Lower Susq
River Valley. Evening temps are ranging through the 70s with
dewpoints ranging through the 40s to near 50F south with a light
breeze. Lows will generally be in the 50s. Patchy fog is
possible after midnight under mainly clear skies with decreasing
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
11 PM Update...
Additional MCSs (or their remnants) upstream are progged to
arrive at our CWA between 14-16z. The last few runs of the HRRR
show an intensifying MCS near I-99 by noon and pushing into
eastern PA through the late afternoon hours. As the MCS enters
the Lower Susq around 18z, the HRRR shows it tapping 2000-2500
J/kg MLCAPE, 35-40 kt 0-3 km SWrly shear, and 40-45 kts 0-6 km
WSW shear, parameters which suggest severe wind potential with
the MCS at least over our southeastern zones and maybe extending
northward through the Susq valley. SPC will consider upgrading
the MRGL to a SLGT for Fri on the overnight update, but they do
point out uncertainty with timing and CI.
Although a large majority of the severe potential appears to be
with linear convection between 14-20z, we can`t rule out
isolated severe discrete cells developing behind the MCS through
the early evening hours. CAPE will likely rebound to 2000+ J/kg
over western zones as temps warm into the 80s. Low level wind
shear and veering will remain strong as warm air advection
commences behind the warm front. CI will depend on the presence
of triggers (perhaps intersecting cold pools and/or terrain?),
but there is a conditional risk for isolated severe weather
after 20z if any deep convection does develop.
High temps now look like they`ll be impacted by clouds and
convective cold pools, with consensus of NAM, NAM12, HRRR
indicating significantly cooler maxes than we have out. Even NBM
has lowered from previous solutions, and we believe maxes will
be 3-5 degrees lower than previously forecast as a result. Have
knocked down Friday afternoon highs as a result with this
evening (Thu) update.
Went with the mid range of QPF solutions at this point and
painted 2-3 tenths across the Central and Southern part of the
CWA. Should the MCS follow in line with several of the Hi res
members, rainfall amounts could be locally 0.5-1.0 from a few
TSRA tracking over the same location.
*Surge of summerlike heat and humidity will bring the hottest
weather since last summer to central PA with record
challenging/breaking temperatures Saturday
*Be mindful of heat stress impacts given limited exposure and
acclimation this early in the year. Stay hydrated!
Broad southwest flow will contribute to a surge of summerlike
heat & humidity to close out the week as an anomalous upper
ridge builds over the Eastern U.S.
High temps Friday still progged to recover into the upper 70s
and 80s for most, but the real heat comes on Saturday with some
record challenging maxTs Saturday afternoon.
Very muggy conditions in store for Friday night with lows
holding in the 60s or +15-25F above normal. These low
temperatures are likely to daily record maxi- mins (record warm
low temperatures) across most of the area. See the Climate
section for context on possible record warmth.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
An amplified upper ridge of high pressure will situation itself
over the US East Coast late this week into the weekend,
funneling Gulf moisture and enhanced warmth into the Keystone
State. Dewpoints surge into the mid 60s with max Ts reaching
well through the 80s and lower 90s. GEFS highlights greatest
areas to see temps above 90 on Saturday in the far SE, south
central PA, and middle susq valleys. Record daily high
temperatures will be approached at all climate sites in our area
(see climate section of the AFD). Early arrival of unseasonable
heat will be impactful despite Heat Advisory criteria not being
reached. Sunny skies will start Saturday off (wear your
sunscreen!), but afternoon cumulus may develop off the higher
terrain and move east. Something to watch is interactions with
the Erie lake breeze for stronger convection to fire and move SE
into our NW counties. Instability will be high with the hot and
steamy surface conditions, and deep layer shear will be
sufficient enough to support organized storms. Outside of NW PA,
there will be little forcing for storm development, though an
isolated t-storm cannot be ruled out for Saturday afternoon.
Saturday night will be warm once again as 850 temps remain in
the 15-20C range. Record daily min Ts will likely be broken
For Sunday, an approaching cold front out of the Ohio River
Valley will increase storm chances for Sunday afternoon.
Temperatures will still be hot ahead of the front - upper 80s to
low 90s - and dew points still juicy in the mid 60s. Storms
Sunday afternoon could be strong to severe with favorable
instability, but marginal shear. the greatest severe risk is
highlighted in SPC D4 outlook which has a 15% threat area across
our northern counties where the shear will be most suitable for
The cold front will cross our area through Sunday evening and
overnight, ushering in a more comfortable airmass. Monday and
Tuesday will be drier and cooler with high temps in the 70s both
days. Chances of rain showers will be non-zero in the southeast
those days with onshore flow developing from a surface high off
to our northeast. Isolated showers, clouds, and cooler weather
lasts through most of Wednesday, then models begin to diverge on
the progression of a low pressure system moving out of the
Midwest and over the Great Lakes region. Depending on how the
low evolves, we may see more showers and storms Wednesday night
through Friday, but a lot of uncertainty exists. If it remains
unsettled and stormy, temperatures will also stay cooler and in
the 70s from abundant cloud cover.
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Winds diminish quickly this evening and much of the night will
be fair and VFR. Some marginal 30 kt LLWS is possible around
daybreak as SW flow strengthens to near 40 kts at 2kft and winds
remain 10 kts or less near the ground. There is still a chance
for patchy fog, but coverage will likely be limited by mid and
high clouds resulting in inefficient radiative cooling. Some
remaining wind will also disrupt fog formation.
Areas of MVFR to IFR cigs and vsby will develop early Fri
morning across mainly the southern and western airfields as a
cluster of showers and TSRA moves east from the Ohio Valley. A
few storms may be severe, particularly across the southeast. By
late Fri afternoon, most places will improve to VFR outside of
Low level wind shear will increase Fri night in a warm air
advection regime as SW flow increases to 40-50 kts at 2kft AGL.
Sat...Primarily VFR, although an isolated late-day TSRA is
Sun...Numerous SHRA/TSRA with cold frontal passage.
Mon...Lingering SHRA across the southeast.
Tue...Scattered SHRA mainly across the south
Near-record warmth is possible Friday night through Sunday
morning across Central Pennsylvania. Several locations are also
likely to have their first 90F day so far this year. NBM
probabilities of temperatures greater than 90F on Saturday are
>75% for almost all of Pennsylvania. Although nowhere near the
earliest first occurrence of 90F, it would be a week or two
ahead of average for most of the area.
Daily record highs for Friday 5/20 and Saturday 5/21:
MDT 94/1996 | 95/1941
IPT 96/1996 | 95/1941
AOO 92/1996 | 89/1977
BFD 86/2021 | 86/2021
STC 91/1996 | 91/1941
Daily record warm lows (maxi-mins) for Saturday 5/21 and Sunday
MDT 68/2004 | 69/1911
IPT 65/1911 | 66/1959,1911
AOO 68/1975 | 66/2018
BFD 63/1959 | 62/2013,1984
STC 72/1996 | 69/2013
Area Forecast Discussion
National Weather Service Dodge City KS
527 PM CDT Thu May 19 2022
...updated aviation section...
.SHORT TERM...(This evening through Friday)
Issued at 318 PM CDT Thu May 19 2022
Strong southerly winds will continue this evening into the early
part of the overnight period with an increase in high level
cloudiness. After midnight, a strong cold front will sweep through
western Kansas and envelop the entire CWA by sunrise tomorrow.
This will shift winds to the north with an increase in speed. Wind
speeds will be the highest shortly after fropa with a slight
decrease as the day progresses. None the less, strong northerly
winds will be felt throughout the day. Dry air will filter in
behind this front with mostly clear skies expected through
tomorrow. As for temperatures, lows tonight are expected to range
from the mid 40s across west central Kansas to low 60s across
south central Kansas. Highs tomorrow look to range from around 70
degrees across west central Kansas to upper 70s along the KS/OK
.LONG TERM...(Friday night through Thursday)
Issued at 318 PM CDT Thu May 19 2022
Cold air advection continues Friday night through Saturday with an
increase in cloudiness. A chance of precipitation will be possible
across west central Kansas and along the I-70 corridor with a few
sprinkles anticipated elsewhere. Northerly winds continue through
Saturday night then shift to the south Sunday as the area of high
pressure shifts eastward. Cloudiness will also decrease in
coverage Sunday. The next system starts to affect western Kansas
Monday and continues into the mid part of next week as a shortwave
digs into the Central Rockies and spins into an upper level low by
Tuesday night. Ensemble models then diverge on the track of this
system with the operational GFS sliding this feature to the south
of the area with the operational ECMWF having this feature
trekking to the north. Nevertheless, the probability of
precipitation look increase during the first part of next week. As
for temperatures, below normal highs are expected Saturday with
mostly places only reaching into the 50s with around 60 degrees
along the KS/OK border. Highs then moderate into the 60s Sunday
and Monday with 70s returning by mid week.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 525 PM CDT Thu May 19 2022
A Nebraska cold front will move southward over the heart of the area
by Midnight, and then into Oklahoma by 12z Saturday. An increase
in cloud cover overnight will be limited to high and mid levels,
with very high ceilings that won`t impact terminals. One caveat is
near the HYS terminal where HREF low Layer Cloud mean image has
around a 25 percent chance of lower stratus behind the front
towards the 10 to 14z timeframe - still quite low. HRRR visibility
fields show unlimited vsby area-wide Tonight.
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 76 43 57 / 0 0 10 0
GCK 51 73 41 55 / 0 0 10 10
EHA 51 76 41 58 / 0 0 0 10
LBL 54 76 43 59 / 0 0 0 0
HYS 52 73 43 54 / 10 0 20 10
P28 61 80 51 61 / 0 10 20 0
Red Flag Warning until 9 PM CDT /8 PM MDT/ this evening for
Area Forecast Discussion
National Weather Service Des Moines IA
625 PM CDT Thu May 19 2022
Issued at 613 PM CDT Thu May 19 2022
The scenario of the warm front surging into Minnesota and placing
the better wind shear environment closer to Interstate 90 has played
out thus far. Therefore, our northern counties have not seen much in
the way of discrete activity. This has been occurring in southeast
Minnesota and southwest Wisconsin. A few elevated supercells also
occurred north of the warm front closer to the MSP metro.
As of 2230z, there were few updrafts going up along Hwy. 18 in far
northern Iowa. Day cloud phase satellite imagery did show slightly
deeper cumulus clouds developing, and some weaker reflectivity
values were showing up the KDMX and KMPX radars. For now, expect
initiation to happen in far northern Iowa, but the storms will need
to move northeast closer to the warm front to realize the 0-500m SRH
above 100 m^2/s^2. Upper-air soundings launched by the TORUS Field
Campaign have indicated strong boundary layer mixing on the warm
side of the warm front, with dewpoint depressions over 30F. At the
start, convection likely had a hard time going because of dry air
entrainment. Now with several failed attempts, there probably has
been in an increase in mid-level moisture that allowed subsequent
convection to become deeper. However, the cloud bases remained high
with LCLs over 1500m, and over 2000m in some places, and therefore
not realizing any low-level helicity. The WoFS members have
drastically backed off the UH tracks south of Interstate 90,
matching the trends we were seeing in radar. A few thunderstorms are
expected across northern Iowa. The tornado threat has greatly
diminished. With the strong mixing, theta-e deficits from the
surface to the top of boundary layer have increased. If a
thunderstorm becomes mature, a strong cold pool could lead to
damaging winds, and mid-level lapse rates may still support a hail
threat. However, storms in northern Iowa likely will not become
mature until they cross into Minnesota.
Attention then turns to the dry line and cold front west of the area
south of the main surface cyclone. Day cloud phase satellite has
shown some cumulus developing over west-central Iowa in the past
hour. Ahead of the cold front, is an airmass with dewpoints in the
60s, and MLCAPE values around 2000 J/kg. There still appears to be
some weak capping, but not strong enough to hold back the
convergence along the cold front. Earlier runs of the HRRR had
little to no activity along the front. Since the 21z HRRR run, there
is more activity which has been lining up with our thinking based on
observational trends, and matches what other CAMs had at their 12z
morning runs. WoFS members do not have much along the line, but
today the WoFS seemed to need CI before it could catch onto the
trends with the warm front. Therefore, will expect WoFS to provide
better guidance after 00z, once more activity develops ahead of the
cold front. The 0-6km bulk shear vector will be in excess of 40 kts,
but mostly parallel to the cold front. The HRRR does not yet depict
a textbook QLCS, rather the HRRR tries for discrete convection, and
then develops more of an MCS. Current environmental parameters would
suggest a QLCS mode is more favorable, somewhat similar the 12z NSSL-
WRF solution from this morning. Straight line winds with a strong
cold pool will be the main threat with storms/QLCS along the cold
front. Initially, a few updrafts may produce hail, but this will
likely be short lived. 0-3km bulk shear values will around 30-35 kts
ahead of the boundary, but also oriented parallel. With this, still
am not expecting a mesovortex generation threat. However, if a rear-
inflow jet develops and orients a part of a line perpendicular to
it, there may be some spin-ups. But, this does not seem highly
probable. There is a shower along Hwy. 30, this could be the
indication of initiation and that the cap is no longer a problem
along the cold front. Some storms may become efficient rainfall
producers, but should be progressive enough to not pose a major
flash flood concern. Over the next hour, expect to see a few returns
on radar from west-central Iowa to north-central Iowa. After 00z
seems to be more favorable for storms to increase in coverage area.
Check for subsequent MCDs from SPC this evening regarding convection
along the cold front. The need for a Severe Thunderstorm Watch north
of Interstate 80 may not be out of the question.
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Thursday/
Issued at 235 PM CDT Thu May 19 2022
--Breezy and warm this afternoon.
--Still watching potential for severe storms tonight.
--Chilly and Rainy Saturday.
--Frost Possible Sunday morning, otherwise clearing, cool, dry.
--Multiple precipitation chances into mid-week with cooler
TODAY THROUGH TONIGHT:
A strong upper-level cyclone is moving from Montana into Minnesota
today with a surface low that developed downstream and was located
over southern South Dakota early this morning. An associated
surface warm front was draped across northern/northeast Nebraska
and northern Iowa ahead of the low which is expected to continue
to push eastward into this evening hugging the Iowa/Minnesota
border before moving a bit more northeast into southern Minnesota
later tonight. This front was the spark of morning convection that
caused scattered showers and thunderstorms across northern Iowa
and initially produced pea size hail in Palo Alto county around
8am with a few cells that perked up along the Iowa/Minnesota
border closer to 11am becoming a bit more robust with elevated
storms that posed a large hail threat.
Along/near the front and east of the surface low is the expected
area for storms to fire this afternoon though a few caveats remain.
For starters, a persistent MCS across Missouri and Kansas this
morning did disrupt some of the moisture flow coming in from the
south despite mid-level flow from the south/southwest ushering in
warm, moist air into the state. By midday, temperatures across much
of southern into central Iowa were already in the 80s with dew
points in the 50s and 60s. Moisture return is a significant factor
in the severe potential tonight, especially the tornado potential,
which will need some of the more moist dew points in the 60s to
reach the area of best lift near/along the warm front in northern
The morning storms did complicate the afternoon/evening forecast as
the warm front appears to not be lifting north as quickly but if it
does continue to push further northward, the severe threat,
especially the tornado threat, may remain north of the IA/MN border
as this boundary is definitely the area with the best potential for
discrete supercells to form. Effective shear near the front is still
around 35-40 knots, despite the better shear being behind the
boundary. Storms that fire along the front will be capable of all
severe threats - large 2"+ hail, damaging wind gusts and tornadoes.
The window for tornadoes is pretty small, from roughly initial
formation around 3-4pm or so and then continuing to maybe 6 or 7pm.
Storms are expected to grow upscale and become more linear as the
develop back to the southwest. This may end up being the better show
for storms in our area, though definitely don`t want to discount the
storm threat this afternoon in parts of northern Iowa with strong
instability - upwards of 3000-4000 J/kg of CAPE in a band right
through parts of western into central Iowa. To summarize, the
tornado and large threat are the initial threats, trending to
more of a wind threat as storms continue. One last note, the
hodographs are very favorable if a discrete storm can persist. See
the mesoanalyst discussion for further details in current storm
Behind the cold front passage, much cooler air
arrives as mid-level flow turns northerly to northwesterly into
Friday. Temperatures Friday morning will be in the 50s across the
northwest half with some 60s still remaining in the southeast half
of the state as the cold front continues to progress through the
state. The boundary stalls out to the south and east - across
southern Missouri extending northeastward into Illinois - with a
upper level positively tilted trough progressing eastward across the
Mountain West through the day Friday. Some clearing is expected,
especially later in the day Friday, with temperatures only climbing
into the 60s to low 70s. The progressing trough will interact with
the stalled boundary Saturday into Saturday night resulting in
cloudy conditions with rain showers continuing off and on much of
the day Saturday. H850 temperatures do drop to below freezing in
northern Iowa on Saturday morning with continuing mid-level
northerly flow helping to reinforce the colder air, but surface
temperatures in the 50s will not force us to discuss any other
precipitation types. Minimal instability with dew points in the 30s
and 40s will generally keep us as all rain with current PWATs of 0.5-
1" not suggesting any significant QPF either. Regardless, it will
certainly be chilly and wet Saturday for most.
SUNDAY AND BEYOND:
High pressure builds in Saturday evening into
Sunday leading to clearing conditions which may drop temperatures
into the mid to upper 30s, especially across northern Iowa, but also
into the valley areas of western Iowa. This may ultimately require
some frost headlines on Sunday morning before temperatures rebound
into the upper 50s to 60s, though still below normal for this time
of May. The 60s temperatures look to hang around into at least mid
week with additional chances for precipitation on Monday into
Tuesday and Tuesday night into Wednesday with a passing shortwave
and low pressure system. Some spatial and timing differences remain
within the models with the Canadian/Euro faster than the GFS and
thus will continue to monitor trends over the coming days.
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 625 PM CDT Thu May 19 2022
A cold front will sweep across the area later this evening and
tonight, causing gusty SSW winds to veer around to NNW, then
gradually diminish on Friday morning. Thunderstorms are also
expected to develop along and accompany the front, affecting some
terminals roughly between 03Z and 09Z as they progress
east/northeastward. Expect MVFR or lower conditions as the storms
pass through, and it also appears prevailing MVFR ceilings will
follow the frontal passage and persist for a few hours before
gradually rising back to VFR. Amendments are probable tonight
based on short-term radar trends.
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1151 PM EDT Thu May 19 2022
Se Mi will lie between two MCS`s tonight. Remnants of the complex
over Wisconsin will mainly produce ample mid and high clouds across
Se Mi while the the better shower potential largely remains north
and west of Se Mi. The convection across the Ohio Valley is aiding
in the development of some low clouds across south central IL,
forecast to advect into Se Mi toward 11 or 12Z Fri morning under
increasing south flow. Model soundings show a deepening of the low
level inversion toward daybreak which should be efficient at ducting
the MVFR based clouds into Se Mi. Diurnal mixing will slowly lift
the cloud bases before eroding the strato cu field early Fri
afternoon. The deepening of the afternoon mixed layer combined with
the strong SSW low level wind fields will support frequent gusts
over 28 knots by mid/late Fri afternoon.
For DTW...Current model solutions continue to advect an expanding
MVFR stratus deck into metro around 11Z, with the latest RAP
suggesting ceilings below 2k feet. After 15Z diurnal mixing will
result in rapidly rising ceiling heights.
.DTW THRESHOLD PROBABILITIES...
* Moderate in ceilings below 5000 feet Friday morning.
* Low in thunderstorms Friday night.
Issued at 408 PM EDT Thu May 19 2022
Warming trend continues through the remaining daylight hours today
as H8 temps climb into the upper teens after a 10C start per 19.12Z
KDTX RAOB. Warm pre-frontal environment isn`t particularly well
defined yet with a gradual gradient in dewpoints from northern Lower
into the Ohio Valley. Perturbed height field on the back edge of a
shortwave trough affords sparse converge of a few additional
isolated showers near the I-94 corridor before sunset. Lack of
surface observational evidence suggested earlier reflectivity
returns were just virga, but did include a small area of Slight
Chance PoPs. Diverse cloud coverage depicted via GOES visible
imagery this afternoon with plenty of areas receiving full
insolation prior to diurnal cumulus generation paving the way for an
easy run into the mid-upper 70s for highs.
The warm front becomes better defined late this evening before
lifting northward shortly after midnight. Lower column winds back
southwesterly first with LLJ ramping up resulting in strong ThetaE
convergence which moves H8-H7 layer dewpoints sharply higher. Did
scale back PoPs during the late night hours given latest model
trends suggesting difficulty in advecting ample mid-level moisture
under persistent zonal flow which lingers downstream of the inbound
longwave trough. Given that elevated nature of convection, this
lends a lower confidence forecast. Once camp of solutions has a Vort
Max off an orphaned shortwave feature lifting cyclonically toward
Lake Erie and brushing the Metro regions resulting in some early
morning showers. Not fully on-board with this as it`s just the NAM
suite given a more westward displaced track.
Questions remain Friday afternoon wrt to breaking the cap which
currently appears inhibitive based on various forecast soundings.
Minimal NWP evidence exists to defend even isolated coverage of
surface-based parcels for most of the midday and afternoon hours
across the central and southern areas. Not much in the way of
dynamic ascent as the best CVA holds to the northwest. If any cap
erosion does occur, SBCAPE would be in the 1500-2500 J/kg range
posing a severe hail/wind threat. Applied numerous revisions to PoPs
to reflect the lower probability scenario, even within the presence
of decent elevated instability of H7-H5 lapse rates near 7.5 C/km
and 25-30 knots of effective shear. As for temperatures trending
into the mid-upper 80s and perhaps closer to 90F for areas closer to
the MI/OH border, that aspect of the forecast remains well in-tact.
Additionally, did nudge wind gusts up a few knots with the afternoon
period which looks very supportive of gusts in the 30-40 mph range
as boundary layer mixing taps into the enhanced LLJ at the base of
the inversion layer. More sustained storm activity arrives during
the evening and overnight hours as the cold front sags southeast
amidst pre-frontal moisture pooling and FGEN context.
The aforementioned cold front will stall and bisect Lower Michigan
along an angle resulting in a period of wet weather for most of this
weekend. The highest confidence for more cyclical rainfall occurs
near the Tri-Cities which lies closest to boundary, but chances are
favorable across most of Lower Michigan. Automated NBM PoPs of
categorical might be a bit overdone. Temperatures cool off some 10
degrees with the increased presence of clouds and precipitation
while the front remains hung-up. Reorganization of the synoptic wave
dislodges the stationary jetstreak, and allows the front to move
east with decrease coverage of showers Sunday morning into the
afternoon hours. Subsidence and high pressure fills in behind the
front Monday with dry and cool conditions persisting until Tuesday
as anticyclonic flow pumps in from Canada.
Winds remain southwesterly overnight before gusty southerly flow
develops as a low moves into the region during the daytime Friday.
Gusts will strengthen to around 25 knots for nearshore zones with
waves of up to 3-5 feet leading to the issuance of a Small Craft
Advisory for these areas for Friday. Stable conditions will keep
gusts a bit weaker over open waters. Showers are possible across the
area as soon as Friday morning with a cold front moving through the
region later in the day on Friday bringing showers and thunderstorms
to marine zones. Mariners should be prepared for gusty winds, hail,
and lightning within any thunderstorms. Beyond that, winds will
become northwesterly behind the front with chances for showers and
storms remaining for marine zones throughout much of the weekend.
A cold front will stall over Lower Michigan this weekend resulting
in a prolonged period of showers and thunderstorms. Some
showers/storms may produce heavy rainfall rates, especially Saturday
afternoon and evening.Areas of one half to one inch of additional
rainfall may occur Saturday and Saturday night. Minor flooding may
occur, especially with areas that see repeated storms in quick
succession. A quarter to a half inch of rain is possible north of M-
59 Friday evening and overnight.
Lake Huron...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LHZ421-422-
Lake St Clair...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LEZ444.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion...CORRECTED
National Weather Service Goodland KS
822 PM MDT Thu May 19 2022
Issued at 810 PM MDT Thu May 19 2022
Red Flag Warning has been allowed to expire on time as relative
humidity values have risen well above critical fire weather
criteria. Wind speeds have been nudged towards the HRRR as this
guidance has been nearly spot on with the timing and magnitude of
the wind gusts with the FROPA. Wind gusts up to 50 mph can be
expected for 1-2 hours behind the passage of the front. Snowfall
amounts were also cut back a bit to account for the 65+ degree
soil temperatures, as the anticipation is for any snowfall to
struggle to accumulate.
.SHORT TERM...(This evening through Saturday night)
Issued at 255 PM MDT Thu May 19 2022
Across the Tri State area this afternoon, skies are mainly mostly
cloudy to cloudy with temperatures currently ranging from the mid
80s into the mid 90s. Warmest areas are where sunshine is pushing
through the current cloud deck. Winds are southwest around 10-20 mph
with some localized higher gusts.
For the remainder of the afternoon, wx concerns focus on the Red
Flag conditions across the region with the downslope warm and dry
wind. Current cloud cover is not allowing for any detection of fires
and criteria for red flag is close to/being met in some locales.
Will be continuing to monitor for fires through the warning period,
as area drying still despite full sunshine over the area, and could
be worse if skies were totally cleared out.
As the high fire danger wanes this evening, the next wx concern(s)
will be the chances for rain...snow and cold temperatures for the
overnight periods on Friday and Saturday.
The latest GFS/NAM show and upper level shortwave in tandem with a
surface front working south from the north central Rockies. This
system will trigger some light rain/rain showers starting late in
the day Friday and continuing into Friday night and Saturday
morning. Colder air working south on northerly flow behind the front
combined with cooling of the column as it precipitates, will allow
for a rain to snow transition, mainly in Colorado where the coldest
air will be. Despite ground temps being amply warm, a couple inches
of snow is possible for western portions of our Colorado counties
tapering to a few tenths the closer to the KS/NE border you get.
Raised surfaces will be impacted, but most of the snow should melt
nicely when in contact with the warm ground. With clouds and
moisture present overnight Friday into Saturday, have held off on
Overall precip will taper from east to west Saturday/Saturday night
as linger moisture will bring light rain to the area. It might be
just cold enough in western Kit Carson/Cheyenne counties to have a
few flakes mix in with the rain before ending. Cloud cover for the
overnight period will be the deciding factor for this overnight
timeframe for any frost/freeze product and may need to be addressed
on later shifts.
For temps, a wide range for highs on Friday as colder air begins to
work into the CWA. Looking for 50s in the west-northwest up to the
lower 70s in the east-southeast. On Saturday, looking for mid and
upper 40s in Colorado and adjacent KS/NE counties, then increasing
eastward into the lower and mid 50s.
Overnight lows will be below normal starting tonight with mainly 40s
to around 50F east of Highway 83. By Friday night, a wide range from
around 30F west, to the lower and mid 30s stretching into the
Highway 25 area, then the upper 30s to lower 40s in the east. Going
into Saturday night, upper 20s west to the mid and upper 30s east.
With the colder overnight lows and wind for Friday and Saturday
nights, wind chill readings are expected to drop into the 20s to
lower 30s Friday night with coldest readings Highway 27 and west.
For Saturday night, readings in the 20s east to Highway 83, then 30-
.LONG TERM...(Sunday through Thursday)
Issued at 225 PM MDT Thu May 19 2022
For Sunday through Tuesday...models in fairly good agreement that
upper trough will move little with a series of weak waves moving
through the main trough axis. This will translate to below normal
temperatures and occasional chances for precipitation.
Temperatures will warm enough so that snow will no longer be a
concern, but may be cool enough so that with little to no
instability convection will not be a concern either. So, will
have high temperatures in the 50s and 60s each day with lows in
the upper 30s (northeast Colorado) to the middle 40s (Hill City)
Wednesday and Thursday...upper trough begins to move out of the
area and a ridge builds in from the west. However, models still
not in very good agreement on timing of the trough moving out or
evolution of the upper pattern. GFS still insists that the trough
will hang around, with the operational run even cutting off a
closed low centered over Oklahoma by Thursday, meanwhile the ECMWF
shows a ridge axis over the central plains on Thursday. Confidence
in temperatures, weather and cloud cover remain very low for these
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 450 PM MDT Thu May 19 2022
The main story for 00Z TAF period will be the cold front advancing
towards the area resulting in an abrupt wind shift. The cold
front is currently located along I-80 in the Nebraska Panhandle
where gusts of 30-40 mph have been observed. A few hours of
stronger winds looks likely behind the front with gusts up to 35
knots looking most likely, isolated stronger gusts are possible.
Until then winds will remain from the WSW between 8-15 knots with
occasional gusts approaching 15-20 knots.
...Updated for 00Z Aviation Forecast Discussion...
Issued at 319 PM CDT Thu May 19 2022
Warm and windy across the area this afternoon with southerly to
southwesterly winds gusting 30-35 mph in many locations and
temperatures as of 3 PM generally in the upper 80s to lower 90s.
Features of note included a surface low spinning over SD with an
attendant warm front stretching eastward into southern MN and cold
front southwestward into western NE, along with a "punch" of dry
air just ahead of the cold front.
As the cold front advances into the area this evening, should see
at least some shower and storm development along it, though still
lots of uncertainty regarding the spatial extent and strength of
any storms that do develop, with the main "deciding factor" being
moisture availability. OAX 18Z observed sounding did show quite a
bit of dry air through 500 mb, though surface observations did
show dewpoints 5 to 10 degrees higher just east into western IA.
CAM solutions show a wide range of possibilities for the forecast
area this evening, from the HRRR which has consistently shown next
to nothing (maybe some spotty light showers) to the NAM Nest
which depicts a line of storms moving across most of the area, so
confidence isn`t particularly high on how things pan out.
Currently, thinking convergence along the boundary will be strong
enough for storms to develop in the area with decent enough shear,
mainly in the low levels, to yield some sort of storm
organization. With at least initially steep low level lapse rates
and linear storm structure, expect a damaging wind threat. Though
with storms likely forming in the evening, and the limited
moisture content leading to overall weaker storms, may be tough to
get any severe winds to the surface. So to summarize, thinking
we`ll see at least some storm development in the forecast area by
6-7 PM, with a line forming, pushing southeast, and possibly
producing sporadic wind damage, though again, confidence is on the
Behind the cold front, expect much cooler weather heading into
the weekend and early next week, with highs in the 60s most days.
Saturday looks to be the coolest, as highs look to struggle to get
out of the 50s. On top of that, some shortwave energy will likely
be sliding through the area and producing precip chances. So
expect a cool and possibly rainy Saturday (we`re just the
Those precip chances exit by Sunday as surface high pressure
takes over and gives us a dry day. However, the next precip
chances arrive for Monday into Tuesday as another shortwave trough
slides through the area. Models then diverge for the remainder of
the week with some guidance showing a larger scale trough digging
into the central CONUS and eventually cutting off (e.g. 19.12Z
GFS) and other guidance sweeping said trough quickly to the
eastern CONUS and building in upper level ridging (e.g. 19.12Z
ECMWF). The former solution would give us continued precip chances
and cooler weather while the latter would mean the area stays
largely dry and warms back up to near or above average
temperatures by Wednesday.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 610 PM CDT Thu May 19 2022
Some uncertainty on storm coverage this evening as frontal
boundary pushes through and winds shift to northwest then north.
Expect some gusts around 30 knots or more behind the front. As for
TSRA, generally have highest confidence in some storms affecting
KOMA but did not include a prevailing group, just used VCTS. Will
amend if storms develop and it seems like they will affect any of