Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/30/22
Area Forecast Discussion...Updated
National Weather Service Billings MT
921 PM MDT Fri Apr 29 2022
Tweaked the PoPs and skies based on the the current radar and
satellite trends. Recent runs of the HRRR have been hinting
towards some fog potential late tonight given the near surface
moisture from the recent rain. Added some patchy fog to the
Tonight through Sunday night...
Satellite imagery showing a deep upper low moving across southern
Wyoming and shifting into the central plains. Strong upper
divergence, combined with surface convergence along an inverted
trough over central and eastern Montana, was creating widespread
areas of rain and showers across southern Montana and northern
Wyoming. There has even been a few thunderstorms sliding across
far southeast Montana. The precipitation has been mainly rain
across the lower elevations, with snow above 5500 feet. The system
will slide east tonight and rain will gradually taper off from
west to east. Some wet snow is possible tonight as the system
winds down, but not entirely likely, as 850mb temperatures
generally stay above zero. Will keep the Winter Weather Advisory
in place for the Bighorns, as snow will continue this evening
before gradually tapering off overnight. Will cancel the Winter
Storm Warning for the Crazies.
Clouds will decrease from west to east tonight. Will have to
watch for potential for fog over western and central zones, should
clouds clear out quick enough. Will not mention fog for this
forecast package as hi res models were not pointing in that
direction, and not sure if clouds will clear out quick enough to
allow fog to form tonight. Evening or midnight shifts may have to
add this based on how things set up this evening.
Saturday will be dry as an upper ridge slides in. An upper low
then moves out of Oregon and shifts toward Utah Saturday night
into Sunday. This will spread ascent across western and central
zones for a chance of precipitation. The system then weakens and
moves into Colorado Sunday afternoon and night. The focus for
precipitation chances with this system will be mainly over the
southern zones. TWH
Monday through Friday...
Progressive pattern looks to continue through the extended
forecast period, but looking fairly warm through the period.
Upper level ridging will bring drier weather Monday, with highs
climbing into the 50s and 60s across the region. Drier weather
will be short-lived, as the next upper trough approaches Monday
Mountain snow and foothill rain showers are expected by midnight
Monday night. This system looks to move across the region Tuesday
and linger across much of the region into Wednesday afternoon.
Slow progress of the system should allow for temps across central
and eastern zones to climb into mid 50s and lower 60s before
precip set in. Meanwhile, westernmost zones will struggle to
reach 50 degrees. Uncertainty continues with regard to expected
precipitation amount. Central zones look to have a bit better
chance for precip, with a greater than a 50 percent chance of at
least 0.1 inches, while there is less than a 50 percent chance of
0.1 inches over southeast MT. Expect precip to arrive as all rain
for locations below 6000ft, with mountains getting more snow.
Will continue to watch as this system unfolds, for any changes.
Another period of drier weather accompanies short wave ridging
Thursday into Friday morning. Temps will climb into the upper 50s
and upper 60s across the region.
Another deep trough is progged to lift over the region Friday
evening/night, spreading another round of precip across the
region. Late timing of the front should allow for temps generally
in the 60s to around 70. This may add enough additional energy to
support afternoon/evening thunderstorms with the frontal passage.
Expect improving conditions overnight. Expect MVFR to IFR
conditions in SE MT to continue, with VFR conditions elsewhere.
There could be some patchy fog producing localized MVFR to IFR
conditions after 06Z, but confidence of impacts at any terminals
is low. Mountain obscurations, especially in the Bighorns and
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
BIL 033/058 040/054 038/060 039/054 040/056 039/064 041/068
40/U 13/R 30/B 25/R 42/R 11/B 12/R
LVM 029/057 037/048 034/060 037/050 036/056 037/064 040/062
20/B 37/R 31/B 47/R 42/R 00/U 13/R
HDN 035/059 037/057 037/061 037/058 039/058 037/065 040/069
90/B 02/R 31/B 15/R 43/R 11/B 12/R
MLS 040/057 034/057 038/057 038/058 039/058 038/062 041/065
82/R 00/E 20/B 02/R 32/R 11/B 01/B
4BQ 040/055 034/055 038/053 037/058 040/055 038/058 040/063
92/R 00/E 21/B 02/R 43/R 11/B 01/B
BHK 036/055 030/055 033/056 033/056 037/054 037/058 038/061
41/N 00/E 00/B 01/N 22/R 11/B 01/N
SHR 034/056 033/054 035/057 035/058 037/054 036/058 037/065
80/B 03/R 52/R 15/T 65/R 21/B 12/R
MT...Winter Weather Advisory in effect until 6 AM MDT Saturday FOR
WY...Winter Weather Advisory in effect until 6 AM MDT Saturday FOR
Area Forecast Discussion
National Weather Service Des Moines IA
659 PM CDT Fri Apr 29 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Friday/
Issued at 352 PM CDT Fri Apr 29 2022
-Potential for severe storms and locally heavy rainfall tonight as
strong low pressure moves up through eastern Nebraska
-Cool and breezy into the weekend; Scattered showers on Saturday
into Saturday evening.
-Active pattern to persist into next week
Morning/early afternoon rainfall has mostly ended with a few showers
lingering in the north. Otherwise, low cloudiness remains extensive
across much of the state with the theta-e push beginning to increase
in the south this afternoon. Showers and embedded storms are
expected to increase in coverage by late afternoon into the early
evening as the moisture pushes northward across the state. There is
little severe threat from this early activity other than some
locally heavy rainfall. The main show is beginning to initiate in
southern Nebraska and this continues to develop and strengthen in
the instability axis over the next several hours. Thinking is the
the convection takes on a linear form as it moves into Iowa with
damaging winds and a few QLCS type tornadoes possible as it remains
within the low level instability axis. The convection is expected
to weaken as it approaches the I35 corridor as it outruns the
instability axis. However, of interest is the most recent CAMS
runs, in particular the HRRR which is showing much less intensity
than previous runs. This is mostly due to lower instability into
the state of Iowa and subsequent weakening of the line as it crosses
the Missouri River. This will need to be watched to see if
subsequent guidance continues this trend. Overall, the best threat
for severe remains late this evening/early Saturday morning in
southwest Iowa with weakening convection as it moves north and east.
Locally heavy rainfall also remains possible although the
progressive nature of the convection should keep overall values in
Additional shower activity is expected into Saturday with better
threat across the north. Winds remains strong from the southwest
for much of the day and may approach Wind Advisory in the west by
afternoon, so this needs to be monitored. The threat for
precipitation wanes on Saturday night as the upper low begins to
depart to the northeast although winds remain brisk. Clouds begin
to depart by later on Sunday with the approach of the surface ridge
late in the day, but temperatures remain below normal. The next
shortwave passes into the Plains on Monday and moves through the
Midwest by Tuesday morning. Increasing warm advection and theta-e
advection is expected by Monday afternoon as the system approaches.
Strong isentropic lift by late in the day with rain overspreading
the state. The bulk of instability remains south of Iowa although
a few isolated storms seem likely in the south. A midweek break is
expected with low amplitude ridging before another shortwave arrives
by Thursday. This low appears to meander a bit longer with a brief
rex block developing before the low slides to the southeast. Rain
once again is expected an may linger a while before ending.
Temperatures during the week remain below normal with the extensive
cloudiness and/or a primary east to northeast surface flow.
.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 659 PM CDT Fri Apr 29 2022
Primary aviation concerns will be MVFR ceiling restrictions
through much of the period along with impacts of showers and
storms on both ceilings and visibilities. As a line of showers
and storms arrives this evening into the hours after midnight,
TEMPO lines were used for timing and lowered restrictions. After
the line, generally have VCSH with lowered confidence in thunder
at a given terminal. As low pressure moves over western Iowa on
Saturday, scattered showers and a few storms will spiral around
the low for prolonged period of VCSH. Through the period as well,
winds will be gusty and upwards of 25 to 30 knots.
Area Forecast Discussion
National Weather Service Grand Forks ND
1015 PM CDT Fri Apr 29 2022
Issued at 1009 PM CDT Fri Apr 29 2022
Sfc map at 02z shows well defined inverted trough slowly moving
west extending from low in northeast Nebraska north to west of
I-29 in South Dakota to in west of Wahpeton and Detroit Lakes then
to west of Fosston. East winds to the east of the trough and
north-northeast west of it. Majority of the rain is west of this
trough and HRRR and NAM indicate that this trough slowly moving
west thru 12z Saturday into reaching Crookston-Fargo-Gwinner. So
for the overnight majority of the rain west of this. And more
scattered east of this. This trough gets washed out Saturday as
moisture band from south moves in Saturday morning. Rainfall
totals via NDAWN showing widespread 1 to 1.50 inch amounts today
from Michigan ND to Valley City to Forman/Oakes. Also pocket of
near 1 inch Eldred, Crookston to TRF area. Based on what is to
come it would appear a widespread 2-3 inch range is likely for
many areas, except far east. From looking at past model qpf this
would be on the high side of what was shown.
UPDATE Issued at 707 PM CDT Fri Apr 29 2022
Area of rain moving north through the area early this evening.
Overall trends are for northeastern SD into southeastern ND to see
a diminishing trend as streadiest rains are from Bismarck area
into NE ND with another area lifting north from Ada to Thief River
Falls. Rainfall the past 12 hours has been highest in the James
Rive valley, mostly from earlier today with convection, but a
widespread 0.50 to 1 inch in the mid RRV to Devils Lake basin to
Valley City. Will see continued rain overnight, but will see if
drier area in NE SD advances more north or stays in that area.
Also will see how new convection thru the night in Nebraska
affects moisture feed into our region.
.SHORT TERM...(This evening through Saturday night)
Issued at 329 PM CDT Fri Apr 29 2022
Main concern through Saturday night will be the threat for
overland and exacerbated riverine flooding from an expected long
duration moderate rainfall event. Impacts expected from overland
and riverine flooding mainly are tied to additional road closures,
flooding of unprotected low lying structures, and some impacts to area
Widespread rainfall is a result of a slow moving upper trough and
assoc sfc low will move through the Central Plains into mid-
Mississippi Valley through the weekend. Widespread rainfall is
already revealing itself with an inverted trof setting itself up
within the eastern Dakotas. This feature is expected to focus
steadiest rainfall, with still some uncertainty of where it will
reside the longest. Morning hi-res guidance indicates a high
likelihood (90%) of at least 1 inch amounts through Sunday.
Incorporating the latest CAMS, the NBM has shown this increase in
forecast amounts, now revealing around 50% chance of seeing 2-3
inches within all of eastern North Dakota into the Minnesota Red
River Valley. Again the higher amounts will be dependent on the
inverted trof`s placement, but it looks like this feature will
reside within the CWA for an extended period of time.
Rainfall rates are generally expected to remain in the 0.2 - 0.4
inch per hour, which decreases the potential to see sudden onset
of flash flooding. However these rates over a 12 hour period over
any one location brings the potential to see overland flooding
redevelop across the region, especially with saturated soils
already in place. It is worth noting that efficient rainfall
processes are expected through higher freezing levels, weak
instability, and continued forcing for ascent.
Rainfall will begin to diminish in coverage and intensity on
This will also impact currently high river water levels. More
details on riverine and overland flooding details are within the
Hydro section of this AFD.
.LONG TERM...(Sunday through Friday)
Issued at 329 PM CDT Fri Apr 29 2022
Below average temps persist during most of the extended period,
with scant chances for any rainfall that might be deemed
High pressure will move in Sun night into Mon in the wake of the
weekend rain maker. Below average temps will still be the rule for
Mon and Tue, but it will be dry. Beyond then, another event is
possible during the middle of next week. Latest guidance indicates a
more likely southern track for this midweek system. There are very
low probs for even up to 0.25 inch QPF over our extreme south. Upper
high building over northern plains should have a lot to do with
suppressing upper low as it ejects from Central Rockies and takes
the more southern route.
For temps, still well below normal until the very end of the end of
the extended forecast period. 850 mb temps in the near 0C area will
gradually improve with time. The good news is that ECMWF and GEFS
ensemble probs indicate a sure bet of greater than 50 degree
max temps from Wed and beyond.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 707 PM CDT Fri Apr 29 2022
For most of the region IFR conditions expected either in ceilings
or visibilities through the pd. There will be times of MVFR
cigs/vsbys more so SE ND into MN.
Issued at 329 PM CDT Fri Apr 29 2022
River and overland flooding continues across much of the
basin due to recent snowmelt and heavy rainfall. River forecasts
incorporate forecast precipitation through 7 AM Saturday. This
weekend`s rainfall will cause prolonged high water levels,
with potentially additional rises in water levels. River forecasts
will continue to vary as more forecast and observed precipitation
is incorporated into the river forecast.
Red River mainstem...
Moderate to major flooding is ongoing or anticipated at Grand Forks
and areas downstream. East Grand Forks has crested, and Oslo is
cresting within major flood stage. Downstream at Drayton and
Pembina, major flooding is still forecast starting early next week,
with Pembina`s crest still beyond the seven day forecast window.
Precipitation over this weekend and potentially next week
continues to lower confidence in crest timing and values at
Drayton and Pembina, with crests potentially becoming higher and
later than currently forecast.
Little to minor river flooding is currently ongoing at Fargo and
points upstream. Future precipitation will prolong high water levels
and potentially cause additional rises in water levels.
Most tributaries farther away from the mainstem Red River within
northwest Minnesota have already crested, but remain high in water
levels as the flood wave exits towards Red River. Points closer to
the Red River are seeing crests or prolonged high water as local
basin flood waves move through and/or backwater from the mainstem
Red River prolongs high water. Minnesota tributaries within the
southern Valley are seeing little to minor flooding, with the more
significant flooding staying within the central and northern
Future precipitation will prolong high water levels and
potentially cause additional rises in water levels.
North Dakota tributaries...
Similar to Minnesota tributaries, many tributaries farther away from
the mainstem Red River within eastern North Dakota have already
crested, but remain high in water levels as the flood wave exits
towards the Red River. Points closer to the Red River are seeing
crests or prolonged high water as local basin flood waves move
through and/or backwater from the mainstem Red River prolongs high
water. Notable tributaries that are seeing prolonged moderate to
major flooding include the Pembina and Sheyenne rivers.
The Sheyenne River will see slow rises into next week as water
release operations continue at Baldhill Dam upstream of Valley City.
All forecast points along the Sheyenne are expected to reach into at
least moderate flood stage. Currently, points at Valley City and
West Fargo are forecast to reach major flooding next week. Crests
are expected to occur beyond the current seven day river forecast
window downstream of Valley City.
Future precipitation will prolong high water levels and potentially
cause additional rises in water levels.
Widespread overland flooding as a result of last week`s rainfall has
begun to diminish as water moves into nearby tributaries/rivers
as well as infiltrate into the ground. However, overland flooding
still remains impactful mainly within the northern half of the
Valley from around Grand Forks County to the international border.
Future precipitation reintroduces the chance for additional
overland flooding, especially within eastern ND and within the
Upcoming weather and impact to river levels...
Between Friday and Sunday, confidence is high that the majority of
the area will see at least 1 inch of widespread rainfall. Chances
for 2-3 inches have increased to 50% for eastern North Dakota and
the Red River Valley. The additional rainfall will prolong
flooding or delay crests, as well as reintroduce risk for overland
flooding. Expect adjustments to river forecasts as forecasted and
observed precipitation is incorporated into the models.
ND...Flood Watch through Sunday morning for NDZ006>008-014>016-024-
MN...Flood Watch through Sunday morning for MNZ001>009-013>017-
Area Forecast Discussion
National Weather Service Goodland KS
858 PM MDT Fri Apr 29 2022
Issued at 838 PM MDT Fri Apr 29 2022
Updated forecast for the batch of showers and gusty winds
currently moving through the central part of the forecast area.
Expectation is we could see come scattered showers with an
isolated thunderstorms or two mainly north of Interstate 70 as the
area of showers moves off to the east and a few more showers
develop and move along the Nebraska and Kansas border region
UPDATE Issued at 609 PM MDT Fri Apr 29 2022
Based on radar trends, have opted to cancel the Tornado Watch
early. Most of the active convection has moved east out of the
forecast area, prompting cancellation.
.SHORT TERM...(This evening through Sunday)
Issued at 216 PM MDT Fri Apr 29 2022
At the beginning of the short term period, the latest RAP analysis
shows the CWA having a southwesterly to southerly flow aloft with an
negatively trough just off to the west. Current surface obs and
radar imagery shows northern Yuma county starting to see some
precipitation developing as the late morning storm in that area has
departed towards Imperial, NE. Going into the evening hours, models
show the base of the trough moving over the CWA with upper air lows
developing in western NE. At the surface, the western KS surface low
looks to move eastward into central KS by the evening before moving
northeast into NE overnight. The Red Flag Warning remains in effect
for Cheyenne (CO), Greeley and Wichita as breezy winds and relative
humidity values down to around 15 percent are expected this
afternoon. Will continue to monitor this. As for the severe
thunderstorm threat this afternoon and evening, currently seeing two
areas of interest. The first area looks to be the northeastern
portions of the CWA (Red Willow, Decatur, Norton, Graham, Sheridan)
with HRRR and RAP models showing a possible supercell developing
around 21-22Z. SPC Mesoanalysis shows some CAPE values above 2000
J/kg around this time for the area as well as some other parameters
making the environment favorable for strong winds, large hail, and a
possible isolated tornado: DCAPE over 1000 J/kg, 700-500mb LR above
8 degrees Celsius per km, SFC-1 km SRH around 60 m^2/s^2 and SHIP
and STP values above 1. After collaboration with the SPC and
surrounding offices, a tornado watch was put into effect until 02Z
for these counties. The other area of interest looks to be the CO
counties where storms have started to developed in the BOU CWA which
will move eastward into the CWA. At the moment, possible threats
look to be mostly strong wind gusts with some hail as CAPE values
are around 1000 J/kg. While precipitation chances started, the
latest HRRR model shows these storms making their way eastward and
stay along the I-70 corridor and ending their threat around 02Z.
Will be monitoring this situation should conditions change. For
tonight, overnight lows look to range between the middle 30s and
For Saturday, models show the upper air low moving northwest into
western NE in the morning and then farther north near the IA/MN/SD
border in the evening with a ridge moving over the Rockies giving
the CWA a northwesterly flow aloft by the evening. At the surface, a
High Wind Warning is in effect starting 06Z lasting through 21Z as
forecast soundings for a good portion of the area possible winds
particularly between 09-15Z with 50+ kt wind gusts especially if
there is good mixing. Precipitation chances look to be well off to
the east for Saturday as they leave with the low pressure system.
Daytime high temperatures look to be in the lower to upper 60s
following the cold front passage from the previous day with
overnight lows in lower to upper 30s.
On Sunday, forecast guidance shows the ridge moving over the CWA
during the day with a trailing trough in the west that starts to
turn the CWA`s upper air flow southwesterly overnight. During the
late afternoon into the evening, models also show a shortwave
disturbance making its way through the flow from west to east. At
the surface, a warmer airmass moves in during the day and there also
looks to be some good amount of moisture brought in from the south-
southeast in the 850mb layer by the evening hours. Models are
showing a pretty good chance for moisture during the evening and
going into the overnight hours. Current QPF values look to range
almost up to 0.5 inches in some locations. Will continue to monitor
this situation but while thunderstorms are possible, chances for
these storms to become severe look to be low at this time based on
forecast parameters. Daytime highs for Sunday range between the
lower and middle 70s followed by overnight lows in the middle 30s to
.LONG TERM...(Monday through Friday)
Issued at 1250 PM MDT Fri Apr 29 2022
Monday...a strong compact upper low pressure area embedded within a
larger upper trough axis moves into the forecast area during the
day, out of the area quickly shortly after sunset with weak upper
ridging overnight ahead of another low pressure system in southwest
Idaho. There is favorable moisture in the 850-500mb layer with cold
500mb temperatures as low as -18C. This all supports chance to
categorical pops across the area during the day, quickly decreasing
early in the evening with dry conditions before or just after
midnight. Surface winds will become breezy to windy as the low moves
through during the day, decreasing quickly after sunset. High
temperatures will be rather chilly with upper 40s to lower
70s...coldest in Yuma county, warmest in Greeley/Wichita counties.
Low temperatures drop into the middle 20s to lower 30s.
Tuesday...a 553dam low pressure center is forecast to be over Salt
Lake City by the end of the day moving a tad east overnight.
Moisture in the 850-500mb layer recovers during the night as well as
the boundary layer. Dry conditions are expected during the day with
a chance for rain showers during the night. There could also be some
fog given the saturated boundary layer. Winds gradually become
breezy to windy from the southeast from late morning through the
afternoon, slowly decreasing overnight from an east to east-
southeast direction. High temperatures are expected to range from
the lower to middle 60s which may be a bit optimistic give the
GFS/GEM/ECMWF 850mb temperatures. Low temperatures are forecast to
be in the middle 30s to lower 40s.
Wednesday...the broad upper low center mentioned above makes its way
into the forecast area overnight. There looks to be a considerable
amount of cloud cover and with plenty of moisture and lift high
chance to likely pops look reasonable for showers and thunderstorms.
With 850mb temperatures in the 4C to 9C range and the cloud
cover/precipitation high temperatures will only be in the lower 50s
to lower 60s. Low temperatures will be near normal in the middle 30s
to middle 40s.
Thursday...Wednesdays upper trough moves through during the day then
out of the area during the night with some short wave ridging moving
toward the Continental Divide. We`ll continue to have a chance for
showers and thunderstorms, mainly during the day. High temperatures
reach the upper 50s to middle 60s with low temperatures in the
middle 30s to lower 40s.
Friday...the current forecast is calling for high temperatures in
the middle 60s to around 70 with generally dry conditions and some
breezy southerly winds.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 853 PM MDT Fri Apr 29 2022
VFR conditions are expected with winds gusting to 50kts as an area
of scattered thunderstorms moves across the GLD TAF site through
04Z with some MVFR possible as visibility decreases with moderate
rain showers. After 05Z, showers should move out of the area and
winds will increase through the night and into the day tomorrow
with sustained northwest winds around 30kts and gusts approaching
50kts after 12Z.
MCK will have VFR conditions with scattered thunderstorms moving
through the area between 08-11Z. Winds will increase through the
night and into tomorrow with sustained northwest winds of 30-35kt
and gusts to 50kts after 16Z.
KS...High Wind Warning from midnight MDT /1 AM CDT/ tonight to 3 PM
MDT /4 PM CDT/ Saturday for KSZ001>004-013>016-027>029.
CO...High Wind Warning from midnight tonight to 3 PM MDT Saturday for
NE...High Wind Warning from midnight MDT /1 AM CDT/ tonight to 3 PM
MDT /4 PM CDT/ Saturday for NEZ079>081.
Area Forecast Discussion
National Weather Service Grand Rapids MI
730 PM EDT Fri Apr 29 2022
.DISCUSSION...(This evening through next Friday)
Issued at 345 PM EDT Fri Apr 29 2022
-- High Fire Danger --
Dissipation of thicker mid level cloud deck earlier has allowed
for warmer temps and lower humidities this afternoon, with most
sites now seeing RH values of 15-25 percent. High fire danger will
be present through early evening and southeast winds gusting up
to 25 mph could cause any fires to spread quickly. RHs recovering
with sunset as temps fall, with winds slackening off a bit as
well and becoming less gusty.
Minimum RH values on Saturday probably won`t be quite as low as
today with more cloudiness expected, but the winds will be even
stronger with gusts over 30 mph. A high fire danger will likely
develop again by afternoon and remain in place until showers
become more widespread on Saturday evening. Fire danger rating
for conifer fuels is currently in the very high category.
-- Showers Most Numerous Saturday Evening --
The first few bands of showers that head into the region from the
southwest later tonight and Saturday morning (associated with a
lead shortwave coming from the Plains system) may struggle to
reach the ground given how dry the low levels currently are, but
any any heavier showers aloft could wet the ground.
The best opportunity for rain still looks to be on Saturday
evening (00Z to 06Z) and we have continued with categorical pops
during this time. Thunder threat may exist as the low level jet
ramps up and a few hundred joules of cape arrive, but the best
instability stays south of Michigan.
Severe weather threat is quite low given the presence of a strong
low level inversion and the primary threat in the SPC MRGL risk
area would be for isolated large hail from elevated storms.
Deterministic and ensemble guidance trend has been for a decrease
in total rainfall amounts, now ranging from around 0.25 near Clare
to about 0.75 inch along I-94. Passage of the frontal boundary
late Saturday night ushers in dry conditions for Sunday with a
cooling trend expected from west to east.
-- Wet System Likely Monday Night and Tuesday--
Confidence is high that another round of rain and possible tstms
will impact the area Monday night and Tuesday, with rainfall
amounts likely higher than the system Saturday night. Ensemble QPF
trends for this system have trended up over the last few runs, but
the track of the sfc low is still in question. A farther north and
west sfc low track could mean an elevated severe weather risk for
Tuesday along with warmer temps, whereas a more srn track would
lead to chilly temps and more of a stratiform rainfall. Rivers
are currently running high, so hydro could become a concern next
week depending on how much rain falls.
Fcst confidence trails off considerably for the middle to end of
next week but latest solutions are suggesting a return to surface
ridging and dry air during this time frame.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 721 PM EDT Fri Apr 29 2022
Most terminals will be trending toward MVFR Saturday morning as
low level moisture tries to increase and the cloud deck lowers.
Winds will be problematic, with fairly breezy conditions from the
SE gusting 25-30 knots inland and 35 kts at MKG. Initially, given
the dry antecedent conditions Saturday morning, it is
questionable whether any precipitation will make it to the ground
until sufficient RH arrives after 18z. Any showers in this TAF
period are unlikely to substantially reduce visibility. Feel the
18z HRRR has a good handle on the likely evolution of showers
throughout the day, with heavier activity arriving just beyond
this TAF period. Could see a risk for IFR in the 00z-12z Sunday
window as lower clouds as well as TSRA potential arrives.
Issued at 345 PM EDT Fri Apr 29 2022
Have upgraded the Small Craft Advisory to a Gale Warning north of
South Haven as latest guidance is showing strong potential for
gusts over 34 kts at the coast on Saturday. Warmer sfc temps and
deeper mixing that develop in the strong offshore/east-southeast
flow should allow for some of the gustiness created over the land
to extend a bit out into the marine environment. Winds become
southwest on Sunday with frontal passage but winds/waves then
are expected to be just below advisory criteria at this time.
LM...Gale Warning from 8 AM Saturday to 2 AM EDT Sunday for
Small Craft Advisory from 8 AM Saturday to 2 AM EDT Sunday for
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
645 PM CDT Fri Apr 29 2022
.SHORT TERM... (Through Late Saturday Night)
Issued at 255 PM CDT Fri Apr 29 2022
Showers and thunderstorms persist late this afternoon from
central IL southwestward into central MO. This activity is
occurring in association with a vort max moving into west-central
IL, with a southwesterly LLJ and associate moisture convergence
along with weak elevated instability supporting the trailing
activity in central MO. The expected trend through the remainder
of the afternoon is for this activity to exhibit an overall
weakening trend as it lifts east-northeastward. Elsewhere across
eastern MO it is possible to see spot showers and perhaps a storm.
A well-defined warm front currently stretches from south-central
Nebraska across eastern KS and across southern MO and southern
IL. The ongoing showers and storms have effectively retarded
aggressive northward movement, however the front is expected to
gradually retreat northward tonight as a low pressure system
across the central Plains moves northeastward and the trailing
cold front advances into western MO. The lifting warm front could
initiate a few storms as it moves northeast tonight, and it`s also
possible we could see a few elevated storm as well to it`s north
primarily across northeast MO and west central IL. However our
greatest threat of storms will be overnight, as storms originating
in the eastern Plains this evening move eastward through western
MO and into our area. Overall I think this activity will be in a
weakening state, but it may an isolated strong to severe threat
for a few hours as it moves into the western CWA, namely wind and
The activity should progress east through the early morning hours on
Saturday, exiting the CWA by 15z or so. The severe weather threat on
Saturday remains conditional, largely based on cloud breaks and
heating in the wake of the early morning storms. These mesoscale
factors will ultimately dictate the probability and coverage of
additional storms. The 12z HREF guidance suite has shifted back a
bit to the west compared to the 00Z HREF. Present thinking is
that the the combination of low level moisture advection and
modest heating should result in a corridor of MLCAPE on the order
of 1000-1500+ J/KG across far eastern MO and western IL during
the afternoon. The consensus of the CAMS and RAP would suggest
convective initiation from central IL across far east-central MO
towards St. Louis during the early afternoon, with storms
maturing as they move east into southwest and south central IL.
Storm coverage should be scattered with potential for a more continuous
line by mid-afternoon over the eastern CWA. Little has changed
with respect to thinking on storm mode and severe threats. Deep
layer shear and instability are in a favorable parameter space for
organized severe storms, and shear vector orientation to the
front/forcing suggest potential for supercells before upscale
growth may ensue further east. Large hail and damaging winds still
appear to be the primary threat. There remains a low threat of a
few tornadoes, however low level wind profiles still appear to be
a bit veered and the resulting hodographs do not support a large
.LONG TERM... (Sunday through Next Friday)
Issued at 255 PM CDT Fri Apr 29 2022
Sunday still looks tranquil in the wake of the Saturday/Saturday
night system with the cold front well to the east and the upper trof
exiting to the east-northeast. Gusty westerly winds, drier
conditions and seasonable temperatures will be in order.
The latest deterministic and ensemble guidance continues to show an
active weather pattern next week with a series of migratory short
wave trofs impacting the region. There is rather good agreement on
the first of these short waves and the attendant lifting warm front
and advancing cold front impacting the region Monday into early
Tuesday. We will have to watch this system and how much the warm
sector opens up ahead of the cold front on Monday night, and the
accompanying instability and threat of robust storms.
Otherwise the models and ensembles continue to diverge with the
second more significant upper trof and accompanying frontal
system later in the week. Present thinking is that we should see
another round of showers and possibly thunderstorms in the
Thursday time frame and possibly into Friday depending on the
timing of the system.
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 644 PM CDT Fri Apr 29 2022
Dry, VFR flight conditions through 06z Saturday, with next round
of showers and storms moving through between 08z and 13z Saturday
with MVFR flight conditions with onset of showers and storms.
Otherwise, another brief break in activity before main cold front
moves through Saturday afternoon. This batch of storms will form
right along boundary, especially over St. Louis metro area between
18z and 21z Saturday. Gusty southeast winds will persist through
tonight, before gradually veering to the south then southwest to
west as front moves through region.
Area Forecast Discussion
National Weather Service Melbourne FL
1035 PM EDT Fri Apr 29 2022
Tonight...It has been a quiet evening with earlier convection
focused to our south and west. However, breezy onshore flow combined
with sufficient moisture, should generate one or more bands of
showers over the Atlc that impinge on the Treasure coast. KMLB radar
shows one convergent band pushing onshore St Lucie county with only
light showers at this time. Additional showers over Palm Beach
county show a gradual drift northward. So have maintained scattered
showers over the Treasure coast counties overnight with the
expectation for redevelopment. The recent HRRR model runs have not
been bullish on shower chances overnight and, like this morning, the
increase in coverage may hold off until around sunrise.
Saturday (previous)... High pressure off the SE US coast will
continue to move eastward through the day. Flow will be zonal across
the area through the time frame. The very weak stalled frontal
boundary across South Florida will continue to stay anchored through
the day, dissipating before early evening. Locally, residual
moisture will remain in place across ECFL through the day, allowing
for higher rain chances to continue with scattered to numerous
showers and isolated lightning storms, especially across the
Treasure Coast in the morning and expanding to the interior in the
afternoon, then western FL peninsula late in the day. The potential
for training cells will occur within convective streamer bands.
These training cells can produce excessive rainfall and flooding
Mainly VFR. SHRA should redevelop VRB-SUA overnight and increase in
coverage Sat morning then shift inland and then the west coast
during the aftn. East winds will continue 10-20 knots.
Have pared back the Small Craft Advisory this eve based on buoy obs.
Will keep the southern waters and offshore Brevard Atlc waters in
the Small Craft Advisory where seas up to 7 FT will remain possible.
Have replaced the SCA with a Caution.
.PRELIMINARY POINT TEMPS/POPS...
DAB 68 81 67 83 / 10 30 20 40
MCO 68 85 67 87 / 10 60 20 50
MLB 68 80 68 82 / 20 60 30 50
VRB 68 81 66 82 / 30 70 40 50
LEE 66 84 66 87 / 10 60 10 50
SFB 66 84 66 86 / 10 50 20 50
ORL 68 85 69 87 / 10 60 20 50
FPR 67 81 66 82 / 40 70 40 60
AM...Small Craft Advisory until 8 AM EDT Saturday for Sebastian
Inlet to Jupiter Inlet out to 60 nm-Volusia-Brevard County
Line to Sebastian Inlet 20-60 nm.
Area Forecast Discussion
National Weather Service Paducah KY
1008 PM CDT Fri Apr 29 2022
Issued at 1008 PM CDT Fri Apr 29 2022
No significant adjustments to the overnight forecast. The remnant
MCV in southwest Indiana (left over from Friday morning`s
convection in northwest Missouri) should continue to slide off to
the east-southeast overnight. Through midnight, this may generate
some light showers over mainly Gibson and Pike Counties in
Otherwise, the WFO PAH forecast area will remain in the capped
warm sector overnight. The 01z Saturday HRRR model run suggests
decayed convection from the current severe storms over Kansas will
weaken significantly over southeast MO and southern Illinois
through Noon. There is a hint that some new convection will
develop on the differential heating boundaries between 2pm and 3pm
on southern Illinois with more vigorous activity develop along the
western edge of the WFO PAH forecast area (southeast MO, southwest
IL) between 3pm and 4 pm. This will need to be monitored for
severe potential on Saturday.
.SHORT TERM...(Tonight through Sunday night)
Issued at 330 PM CDT Fri Apr 29 2022
The primary forecast concern in the near term is the chance for
showers and thunderstorms, primarily Saturday afternoon and night,
along with the potential for strong to severe storms Saturday
afternoon and evening.
Low pressure over the central Plains is forecast to track
northeast into southern Minnesota by Saturday afternoon. A warm
front extending southeast from the low has bisected the forecast
area for much of the day, with more clouds and widely scattered
light showers north of the front and a little more sunshine and
warmer temperatures south of the boundary. While a few showers
cannot be ruled out along the I-64 corridor in southern Illinois
and southwest Indiana through mid evening, the focus for most of
the precipitation should shift to the north and west of the region
overnight. A persistent southerly breeze should keep temperatures
largely in the 60s as well.
On Saturday, remnant convection from overnight showers and storms
in Missouri may impact far western portions of southeast Missouri
and southern Illinois before it diminishes in the morning. At
least partial sunshine by afternoon should kick high temperatures
into the upper 70s and lower 80s, with dew points near 60,
yielding a moderately unstable atmosphere, with SBCAPE values of
1500-2000 J/kg forecast by mid to late afternoon. As the frontal
boundary approaches, isolated to scattered thunderstorms are
forecast to develop and/or move into southeast Missouri and
southwest Illinois by mid to late afternoon. While the coverage of
the activity is initially expected to be isolated to scattered,
deep layer shear on the order of 40 knots should be adequate for
As a result, SPC has much of the region in a slight risk for
severe thunderstorms Saturday afternoon and evening. While
damaging wind is the primary concern, and some large hail is
possible with the initial cores early on, an isolated tornado
cannot be ruled out. The area of most concern is across southeast
Missouri and southwest Illinois late in the afternoon, with a
gradual decrease in storm intensity expected as the storms congeal
into a line and shift east across southwest Indiana and western
Kentucky during the evening. However, a damaging wind threat could
continue well into the evening depending on storm organization
and how much instability remains.
By late Saturday night into Sunday, a return to dry conditions is
expected as weak high pressure builds in. However, any change in
temperature should be largely nonexistent with little in the way
of cold air advection in the wake of the Saturday night frontal
passage. Expect highs of 75 to 80 on Sunday, with lows largely in
the 50s both Saturday and Sunday nights.
.LONG TERM...(Monday through Friday)
Issued at 330 PM CDT Fri Apr 29 2022
A warm front will quickly advance northward on Monday allowing for
700 mb moisture to advect in from the southwest. As a 500 mb
shortwave and sfc cold front begin to approach the PAH FA, a chance
of pcpn increases through the afternoon. Categorical PoPs hold off
until overnight when the heaviest rainfall will occur. During this
time, tstms will also be possible, especially across southeast MO
and far western KY where the greatest instability will be. Late
Tuesday afternoon, the front will eventually move across the area.
It will be breezy with wind gusts upwards of 30 mph, with a chance
of showers and tstms. Showers then linger through the night as
models suggest the frontal boundary will stall near the TN border.
With the front still nearby on Wednesday, lower shower chances
continue to remain possible.
Uncertainty in the forecast period increases during the Wednesday
night/Thursday time frame as models differ on how fast mid level
energy is ejected out of the southwest. The ECMWF wants to hold back
energy which would keep most of the aformentioned period dry.
However, the GFS is the most progressive of the deterministic models
and would support a much wetter outcome with the CMC being a
compromise of the two. While confidence remains low in the
faster/wetter outcome, would lean towards the highest probabilities
of pcpn holding off until late Thursday into Thursday night at this
time. Rain chances may linger into Friday.
High temps will remain on the warm side in the mid to upper 70s for
most of the week except for Wednesday where temps may be a few
Issued at 652 PM CDT Fri Apr 29 2022
For he WFO PAH 00z Saturday TAF issuance, the TAF sites are
becoming focused in the the warm sector, with KMVN and KEVV near
the cusp of the warm frontal zone at this time. Added a mention of
rain early in the period for KMVN with vicinity shower activity
during the evening at KEVV and KOWB.
There is some middle level cloud bases and virga near the southern
WFO PAH TAF sites, but left out for the moment given the sparse
With a westward tilted ridge overhead, anticipate mainly mid/high
level cloud bases overnight across the WFO PAH TAF sites. Given
the slight variance in timing of convection to the TAF sites
tomorrow afternoon, did introduce a transition from VFR to
MVFR/IFR ceilings with this issuance. This will likely change for
the 06z WFO PAH TAF issuance.
Area Forecast Discussion
National Weather Service Phoenix AZ
456 PM MST Fri Apr 29 2022
.UPDATE...Updated Aviation Discussion.
A progressive weather pattern will remain in place through next
week with weather disturbances passing north of the region. This
pattern will keep temperatures similar each day and above normal,
with mostly sunny skies. Breeziness is expected each afternoon
while windy conditions are likely Sunday and Tuesday, with each
passing disturbance. Seasonably dry conditions will continue and
no rain is expected through the next seven days.
Clear skies predominate across the Desert Southwest this
afternoon. Temperatures are running near normal and steadily
rising through the 80s while surface dewpoints are in the lower
30s. Official high temperature forecast for Phoenix is 90 degrees,
but there is roughly a 30 percent chance the high will fail to
reach the 90 degree mark. Meanwhile, 700 mb flow is generally out
of the northwest between a ridge off the California coast and a
trough in the southern Rockies. Latest HRRR indicates the
northwest flow will be favorable to steer lofted smoke from the
Crooks Fire into the Valley later today, though sensible impacts
at the surface should be negligible.
Little day to day change is anticipated beginning tomorrow as a
series of low pressure systems sweep by north of the region and
eastward through the intermountain West. Main impact across the
lower deserts will be a continuation of the daily afternoon
breeziness, punctuated by windy conditions Sunday and again
Tuesday ahead of two slightly anomalous short-wave troughs. Latest
operational GFS continues to trend stronger with these troughs
while the latest ECMWF ensemble suggests wind gusts could reach 30
mph in the Valley with each system. The troughs will not be
strong enough to result in significant cooling and the NBM
indicates a high probability above normal temperatures will
continue through at least next Friday. Tight inter-quartile ranges
are also indicated in the multi-model guidance until next weekend
when uncertainty in the pattern increases.
With the average first 100+ degree day being May 2nd, Phoenix is
looking at a later than normal first day. Three of the years since
2015 Phoenix had their first 100+ degree day after May 2nd,
including last year which reached 100F on May 5th.
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Mainly light winds will generally favor normal diurnal cycles
through the period. On Sat afternoon and early evening some isolated
gusts into the teens are expected. Otherwise skies will be clear
to mostly clear with only FEW high clouds moving across the region
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly light winds will favor normal diurnal patterns through the
period, although with periods of variability as well. Skies will
be clear to mostly clear with only FEW high clouds moving across
the region by Sat.
With a progressive weather pattern and troughs passing north of
the region, the environment will remain dry with off and on
breeziness. The breeziest days are expected Sunday and again
Tuesday, with the passing of the next couple of troughs. Wind
gusts these days could reasonably reach 25-35 mph. With above
normal temperatures in the 90s (low elevations) and Min RHs
between 5-15% each afternoon, elevated fire weather conditions
will remain a concern through the forecast and be heightened on
Sunday and Tuesday. Fire Danger Class from NIFC is already High
to Very High in the CWA and fuels are continuing to dry, with
rising ERCs. Overnight RH recoveries will fluctuate with
occasional surface moisture fluxes from the Gulf of California,
during the night hours, but will mostly be in the 20-40% range.
Still no rain in the forecast and skies will be mostly clear.
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AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
947 PM EDT Fri Apr 29 2022
A front will waver across southern and central NC through Saturday
night, then retreat north into VA on Sunday.
.NEAR TERM /TONIGHT/...
As of 945 PM Friday...
West to nw flow aloft will continue across cntl NC tonight,
downstream of a mean mid-level ridge extending from the Gulf of
Mexico nwd to near Hudson Bay. Within that flow, a 700 mb-centered
warm air advection regime from the mid MS Valley east across the lwr
OH Valley and wrn VA/NC will cause associated altocumulus ceilings
to continue to spread east across cntl NC tonight. Those ceilings
may be accompanied by virga, or patchy light rain/sprinkles after
At the surface, a front and associated convergence axis that
extended at 01Z across srn to nwrn NC, from CTZ to MEB then nwwd to
TRI, will remain quasi-stationary tonight. That front will continue
separate a modified, 1021 mb high pressure cell from offshore the
coast of the Carolinas from 1024 mb, cP high pressure from the Great
Lakes southeast and across the Mid Atlantic.
While the models mostly depict the aforementioned patchy and light
virga/sprinkles, recent runs of both the HRRR and 3km/NAMNest depict
the potential for embedded elevated convection/showers overnight
from 100-200 J/kg of MUCAPE and up to a tenth or two of an inch of
rain on the immediate cool side of the front from near the Triad
southeast across the Triangle and to near GSB and RWI. No such
MUCAPE was evident on either the 00Z-observed GSO or MHX soundings,
however; and regional radar trends do not yet depict a hint of any
such cellular development. As such and for now, we`ve simply
increased PoP into chance range roughly along and north of I-40 (on
the immediate cool side of the front) to account for the elevated
convective potential; and we`ll continue to monitor observational
trends relative to the hi-res forecasts.
Low temperatures will be mostly in the 50s and kept milder by the
aforementioned increase in mid-level moisture/ceilings. The
exception to 50s will be over the nrn Piedmont and nrn Coastal
Plain, where influence from the cP ridge over the Great Lakes will
be maximized and favor cooler, mid-upr 40s prior to the arrival of
the mid clouds.
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 210 PM Friday...
Weak Warm advection will continue above the surface on Saturday,
helping to support a slight chance of a shower across central NC but
mainly from Winston-Salem to the Triangle north and east. Forcing
for ascent is limited to the weak warm advection and there`s little
forecast instability, so any showers should be brief, spotty and
light. Guidance continues to be very inconsistent in the timing but
tends to favor a shift toward the northern Piedmont/coastal plain in
the afternoon, though stronger daytime heating in the sw CWA and
more robust cloud cover across the ne CWA could create a modest
different heating boundary to focus a few showers south of HWY 64.
Highs should range from the mid/upper 60s ne to around 80 sw.
Moisture tends to shift north of the area on Saturday night as the
upper ridge shifts overhead, allowing for better clearing but also
milder lows solidly in the 50s and the potential for some late fog
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 255 PM Friday...
Sun: The mid-level shortwave trough over the mid-Mississippi Valley
from Sat is forecast to track east-northeast into the upper Midwest
and Great Lakes Sun afternoon/night. A ridge axis will extend from
the lower Great Lakes into the Mid-Atlantic and southeast US early
Sun. As the trough to our northwest shifts east, it will send a
shortwave disturbance/trough axis across central/eastern NC in the
late afternoon and evening hours. At the surface, a warm front along
southern VA and northeast NC will lift north into central and
eastern VA by the afternoon evening, placing the region in the warm
sector with MLCAPE of 500-1000 J/kg over the eastern Piedmont and
1000-1500 J/kg in the northwest Piedmont. A surface cold front tied
to the trough is forecast to slide southeast into the lower Ohio
Valley by early Mon. While surface forcing is weak with the absence
of low-level boundaries, sufficient instability with the trough axis
should favor a good chance of showers/storms in late afternoon and
evening, especially over the northwest Piedmont where mid-level
lapse rates and shear are more favorable. Further east, a capping
inversion is noted in forecast soundings, limiting storm coverage as
the line of storms pushes east Sun night. Proximity soundings in the
northwest indicate nearly straight hodographs with about 30-35 kts
of deep-layer shear, along with some high DCAPE. This would support
some potential stronger storms capable of damaging winds or hail.
SPC has only general thunder at the moment but would not be
surprised if a marginal risk is introduced in the next update. Highs
will be above normal as the front lifts north in the upper 70s in the
north and middle 80s in the south.
Mon-Wed: The main story during this period will be increasing heat
and above normal temperatures. High pressure over the western
Atlantic will be in place, with the mid-level flow nearly zonal to
weak ridging. Low-level thicknesses will rise to what is typically
seen in late June to early July. Have went above MOS guidance as a
result with highs about 10-15 degrees above average in the mid to
upper 80s to some lower 90s in the Sandhills and southern Coastal
Plain. A sea-breeze may be the focus for a few isolated
thundershowers Mon afternoon but otherwise most areas will be dry. A
shortwave over the mid-Mississippi Valley Tue will lead to a chance
of showers/storms Tue aftn/night but should largely be confined to
the western and southern Piedmont. A better chance of showers/storms
will exist Wed night with a cold front and a shortwave trough diving
into the Mid-Atlantic.
Thu-Fri: The latest GFS has come in line with the ECMWF in bringing
the cold front from Wed through portions of central NC by early Thu.
Several ensemble solutions also indicate this so highs should trend
lower but still above average in the upper 70s to middle 80s.
Confidence is not great on the southward movement of the front so
the boundary could still be a focus for isolated storms in the south
and west. On Fri, model ensembles more or less show a developing
trough over the Mid-Mississippi Valley, with weak ridging over the
Mid-Atlantic and southeast US. However, there are timing differences
among the guidance on how fast this feature moves into NC. For now,
have only indicated chance PoPs with highs remaining above average.
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 842 PM Friday...
VFR conditions are likely across central NC for the next 24 hours.
Mainly mid level moisture will continue to spread across the area
tonight as a warm frontal zone retreats northward. Consequently, a
lowering of ceilings to ~6 to 8 kft are expected mainly at sites
north of the front (KINT/KGSO/KRDU/KRWI) through Saturday afternoon.
However, by early Saturday morning, increasing low-level southerly
flow may support enough low-level moisture to promote a short period
of MVFR ceilings at KRWI, especially if measurable rain falls, but
confidence in this is low. Otherwise, models continue to suggest
light, spotty rain within the vicinity of the warm front overnight
through tomorrow. Thus, decided to include the mention of vicinity
showers at KINT/KGSO/KRDU/KRWI given that these sites will likely
have the highest chance to see any precipitation. Regardless, little
if any aviation impacts are expected.
Outlook: A weakening cold front moving into the area from the west
will bring additional chances of sub-VFR condition in scattered
showers and thunderstorms Sunday afternoon and evening.
After possibly VFR conditions on Monday, mainly diurnal convective
rain chances are expected on Tuesday, especially across western NC.