Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/24/22

Area Forecast Discussion

National Weather Service Bismarck ND

 930 PM CDT Mon May 23 2022

.UPDATE...
Issued at 926 PM CDT Mon May 23 2022

Other than a lone weak thunderstorm in Bowman County, lightning is
no longer being observed across western and central North Dakota.
Scattered rain showers continue in an arc from near Hettinger to
Devils Lake to Valley City, but these too are showing a weakening
trend.

Several models are simulating fog developing over parts of western
and north central North Dakota early Tuesday morning. The one area
with the most overlap of fog among guidance is from around Stanely
to Tioga, which is a climatologically favorable area for fog
formation. Current dewpoints there are lower than forecast low
temperatures, but some weak surface moisture advection is forecast
to occur through the night. Therefore, enough confidence is
present to add a mention of patchy fog to the forecast. Other
changes for this update were mainly to blend current conditions
and trends into the forecast.

UPDATE Issued at 653 PM CDT Mon May 23 2022

As of 645 PM CDT, the strongest convection has refocused along a
line from near Hettinger to south of Rugby, with radar and
satellite suggesting outflow from earlier convection has at least
in part driven this reorientation. The northern extent of this
line is entering a slightly more sheared environment, but still
likely insufficient for sustained updrafts. Furthermore, boundary
layer stability should be on the increase due to increasing
anvils, evaporative cooling, and waning solar insolation, which
should act to further reduce the already low potential for strong
to marginally severe storms. Ongoing convection is forecast to
slowly migrate eastward through the evening and gradually
dissipate by midnight.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 233 PM CDT Mon May 23 2022

Scattered showers and a few strong to potentially severe thunderstorms
are the focus of the short term period.

This afternoon, a weak upper shortwave trough was approaching the
forecast area, with an attendant surface low in northeast Montana.
There were multiple different areas of showers and a few isolated
thunderstorms -- a broad area in the north central, moving
northeast; a line on the southern and eastern side of the low
extending from north of Billings, MT through northwest North
Dakota, moving east- southeast; and a second line from northwest
South Dakota into south central North Dakota, moving north. A cu
field has been developing across western North Dakota.

SPC introduced a Marginal Risk for severe thunderstorms this
afternoon and evening in a southwest-northeast oriented swath from
the Glen Ullin to Hettinger area through the northeast corner of
North Dakota. The main threat will be marginally severe hail,
with steep lapse rates and cold temperatures aloft. There are a
few caveats that could limit how strong storms can get. Weak bulk
shear (less than 30 knots) and MUCAPE less than 1000 J/kg will
limit the magnitude of maximum hail size, and where values become
close to those thresholds, they do not overlap in location.
Although there is modest southerly flow in the southern and
eastern parts of the forecast area, upstream observations in South
Dakota show dew points are only in the lower to mid 40s at best,
so not much additional moisture advection is expected.
Additionally, the lack of strong surface forcing will lead to a
much more multicell/cluster storm mode, especially with a few
different areas of storms already ongoing. The area that likely
has the highest chance of strong to possibly severe storms is the
convection moving in from South Dakota, which is on the leading
edge of a swath of low- level warm air advection.

The latest HRRR and RAP runs are supportive of convection
developing in a southwest- northeast line about where the Marginal
Risk is outlined, and would likely be an expansion of the ongoing
line currently edging into south central North Dakota. If a few
discrete cells can be sustained in this area, those would have
the highest risk for marginally severe hail the size of a quarter.
Overall timing for any severe thunderstorms is in the 5 to 9 PM
CDT timeframe, with scattered showers and non- severe
thunderstorms persisting until around midnight.

Once showers taper off tonight, skies will clear out, with lows in
the mid 30s to mid 40s. Upper level split flow will begin to
develop on Tuesday, with a trough digging into the Southern Plains
and weaker flow over the Northern Plains. Tuesday will be a
quieter day, with partly cloudy skies and highs in the 60s.

.LONG TERM...(Tuesday night through Monday)
Issued at 233 PM CDT Mon May 23 2022

Warming temperatures ahead of a potentially active holiday weekend
is the focus of the extended forecast.

The split flow pattern is expected to continue midweek across the
central CONUS, with a closed low in the Southern Plains and a
weak trough propagating through the Northern Plains. Blended
guidance continues to carry low-grade PoPs on Wednesday (although
they have diminished some since the previous update) as this wave
brings in a push of warm air advection and the subsequent chance
for showers and a few non- severe thunderstorms.

Ridging that is building upstream of this trough will move into the
central part of the CONUS for the end of the work week, producing
a warming trend and widespread highs in the 70s, with some 80s
possible in the southwest on Friday.

GEFS ensemble members favor a shallower and more progressive trough,
while Canadian members produce a slower and deeper trough, and EC is
somewhere in between. Regardless, CIPS and other extended guidance
is leaning towards a more active pattern for the holiday weekend
and into next week to round out the month of May. There are still
a lot of details to be worked out in regards to specific timing
and the threat ceiling regarding showers and storms this weekend,
but confidence is increasing for widespread chances for
precipitation and cooling temperatures through the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 926 PM CDT Mon May 23 2022

The chance for thunderstorms at KBIS and KJMS appears to have
ended. Some light rain is still possible through 04Z, but radar
imagery suggests a dissipating trend. VFR conditions and light
southerly winds are expected through the forecast period.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Hollan
SHORT TERM...Jones
LONG TERM...Jones
AVIATION...Hollan



Area Forecast Discussion

National Weather Service Grand Forks ND

 1017 PM CDT Mon May 23 2022

.UPDATE...
Issued at 1017 PM CDT Mon May 23 2022

Mid level shortwave over western ND remains in place with forcing
along the elevated baroclinic zone ahead of this features where
SW-NE flow is in place over our CWA. More organized clusters are
over the RRV with just enough elevated instability (500 J/KG or
less) supporting embedded thunderstorms mainly along the leading
edge. As low levels have decoupled and this activity has become
more elevated (and instability weakened) the severe threat has
ended. However there have been occasional gusts around 40 mph with
this activity and where thunderstorms have track frequent
lightning. Main activity is still expected to transition across
our eastern CWA through the night while the weaker isolated-
scattered activity further west slowly weakens as the parent wave
stalls and looses its organization due to more dominant upstream
shortwave ridging. I made some adjustments to reflect near term
trends, but the big picture remains on track for the rest of the
night.

UPDATE Issued at 702 PM CDT Mon May 23 2022

Limited MLCAPE (500 J/KG or less) is still supporting some
embedded thunderstorms within the disorganized clusters of
showers moving into our east. Freezing levels remain very low, so
it won`t take a particularly tall core to produce hail, but still
we are not seeing any updrafts maintain cores much higher than
20kft AGL (heights would need to be closer to 25kft AGL for near
severe hail). DCAPE is much lower as well, though soundings do
align with "inverted V" profiles, so gusts can`t be ruled out.
Effective shear is near 30kt over the Devils Lake Basin, but
overall is very weak in nature. There is a maximum in surface
vorticity along the weak convergence zone, but 0-3km CAPE is
offset to the west and the result is non supercell tor parameter
is not favorable in our area despite the higher vorticity values.
As daytime heating continues to wane RAP shows instability
quickly dropping off. There may be enough elevated instability due
to steep mid level lapse rates to still support clusters of
showers/weaker thunderstorms, but any severe threat would be over
after sunset.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 240 PM CDT Mon May 23 2022

Ahead of a large scale trough aloft, a shortwave embedded within the
upper level flow pattern will impact the northern Plains late this
afternoon into the evening hours. At the surface, southerly winds
continue to advect warm air into the region with afternoon high
temperatures topping out in the low to mid 60s. Moisture at the
surface through the midlevel is generally lacking, however, with
surface dewpoints likely to only reach the low 40s, even with
strong southerly advective flow. This is resulting in inverted V
type forecast soundings across the region, that will likely
contribute to some gusty wind potential. Despite this, some weak
instability on the order of a few hundred J/kg will likely be able
to be realized this afternoon. This is corroborated by latest RAP
mesoanalysis showing a bulge of 250-500 J/kg of MUCAPE working
into south central North Dakota. With the approaching upper
shortwave and an 850 hPa jet aloft, 0-3 km shear in the 20-30 kt
range and 0-6 km shear in the 30 kt range should help to support
some organized thunderstorm development this afternoon into the
evening. Despite the weak instability, the surface boundary should
be able to force convection with relative ease this afternoon.
Once this occurs, look for rapid upscale growth along the boundary
as storms transition eastward. The primary axis for this activity
to develop will be from the Devils Lake basin into northeastern
North Dakota and then eventually northwestern Minnesota. Main
hazards with stronger thunderstorms that do develop will be hail
up to the size of quarters and wind gusts up to 60 mph. While
thunderstorm development is the likely solution, there is the
possibility (~10% chance), still, that the boundary is weak enough
and strong convection does not occur.

Precipitation is expected to subside by late evening into the
overnight hours. Following this shortwave, some transient ridging
aloft should yield some weak subsidence. As a result, cloud cover
looks to become less numerous moving into tomorrow morning and
temperatures are expected to warm back up into the mid to upper 60s
across the region. Given warming temperatures and southerly surface
winds, however, will likely see similar diurnal Cu trends in the
afternoon hours that could produce some minimal impact, spotty
showers. Otherwise, a generally quiet Tuesday is anticipated.

.LONG TERM...(Wednesday through Monday)
Issued at 240 PM CDT Mon May 23 2022

As far as impacts go, it looks like there will be two periods with
higher rainfall potential. One is Wednesday into Thursday, and the
other is the weekend into early next week.

The ECMWF Extreme Forecast Index (EFI) doesn`t appear to be
highlighting any specific parameter at this point. The ensemble
means are showing split flow Wednesday into Thursday, with the
southern stream looking more active. This looks to bring a good
chance for precipitation to southern and eastern Minnesota on
Wednesday, just east of the FA. There could be a weak northern
stream wave on Thursday, that could generate some afternoon or
evening showers. Although 500mb temperatures look cold, they are not
quite as low as they have been the past 3 days when there have been
afternoon/evening showers. High temperatures in the 60s on Wednesday
should transition more to some low 70s by Thursday.

A dampening 500mb ridge axis pushes eastward into the FA on Friday.
There seems to be pretty good agreement on the Day 4 (ending 00Z
Sat) WPC 500mb heights and anomalies with the ridge placement and
timing. This agreement starts to break down by Saturday, Sunday, and
Monday. Overall, the 500mb flow pattern looks to shift back to a
southwest/more active flow. Will have to keep an eye on later
forecasts, but Saturday itself may have the potential to be dry, if
the ridging is slower to move east. Otherwise, waves of
precipitation look to push up into the FA in the southwest flow
through the weekend into early next week. Correspondingly, highs in
the 70s remain likely Friday into Saturday, but they should drop a
little more by Sunday into Monday with the arrival of
precipitation.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 702 PM CDT Mon May 23 2022

VFR conditions should prevail thorugh the TAF period with CU
layers generally in the 7-10 KFT AGL range. Cluster of showers
(some potential for thunderstorms) will progress eastward through
the evening/overnight, with dry conditions favored behind this
system by morning. Southerly winds decrease below 12kt later this
evening increasing once again with daytime heating Tuesday
morning.


&&

.HYDROLOGY...
Issued at 240 PM CDT Mon May 23 2022

Many locations along the Red and Sheyenne rivers remain in at least
minor flooding, although all water levels are either steady or are
currently declining or expected to decline. Some moderate to major
flooding is still ongoing, mainly along the northern mainstem Red
River as well as the lower Sheyenne River.

While chances for precipitation are in the forecast, amounts are
expected to remain generally under a quarter of an inch before
Thursday. Light amounts of this caliber are not expected to cause
any additional, significant rises to rivers. With a lack of
substantial precipitation amounts, high water levels will continue
to recede through much of the week.

There is a chance for more widespread precipitation later next week
after Friday, including the chance for thunderstorms. Widespread
amounts of half an inch or more remain a possibility (20-40% chance
of occurrence) with this late week rainfall. It remains unclear how
this may impact rivers, but at this time we are not expecting
additional significant crests to rivers given the opportunity to
recede through the majority of the week.

River forecasts account for observed precipitation as well as
forecast precipitation between 7 am Monday 5/23 and 7 am Tuesday
5/24.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$

UPDATE...DJR
SHORT TERM...Rick
LONG TERM...Godon
AVIATION...DJR
HYDROLOGY...CJ



Area Forecast Discussion

National Weather Service Paducah KY

 935 PM CDT Mon May 23 2022

.UPDATE...
Issued at 935 PM CDT Mon May 23 2022

Cloud cover rather challenging this evening. After monitoring
observations and guidance, the HRRR and NAM appeart to have a
better handle on the progression of stratus moving slowly
northeast overnight and into Tuesday. The HRRR timing for the
onset of precipitation seems to be in line with the current
forecast package in place for tomorrow afternoon over southeast
Missouri.

UPDATE Issued at 704 PM CDT Mon May 23 2022

Added a few sprinkles of rain to the southern Pennyrile region of
west Kentucky for the next couple of hours as a very subtle
vorticity lobe is providing enough lift in a weak low-middle level
shortwave.

Also kept more aggressive cloud cover across the area overnight.
Will need to watch cloud trends over southern MO/Northern AR to
determine whether there will be sufficient opaque cloud cover
overnight. This may have some impact on temperatures by daybreak
on Tuesday.

&&

.SHORT TERM...(Tonight through Wednesday night)
Issued at 315 PM CDT Mon May 23 2022

High pressure over the Great Lakes region will continue its
eastward movement overnight, with return flow beginning late in
the night and continuing Tuesday. The upper air pattern features
a broad trof over the CONUS and an active southwest flow pattern
over our region. Radar and satellite show convection as close as
northern AR extending back west to OK. After coord with SGF, we
will carry slight chance PoPs into the Ozark Foothills just in
case the convection lasts a bit longer and moves farther east
than forecast.

Most of the day Tuesday will be dry. However by afternoon a weak
impulse will lift north across the TN Valley region. It should
trigger scattered convection that will move toward or just across
the KY/TN state line by the end of the day. Some of the convection
will extend west into SEMO as well.

The HiRes guidance hints at mid level support lifting north across
AR Tuesday night out ahead of the parent upper trof over the
Plains. This will result in a higher chance of showers and storms
with the highest chance over the west 1/2 of the area into SEMO.
Locally heavy rain may be a concern by Wednesday morning with any
repeat thunderstorm activity over SEMO.

On Wednesday, despite the meridional flow ahead of the upper low
over KS, decent instability is forecast to set up along and east
of the MS river. This could set the stage for strong to locally
severe storms as the overall speed shear increases along with the
greater instability present. Locally heavy rain will become a
concern as well over a larger portion of the CWFA, as waves of
low pressure develop along the slow moving boundary across our
region, resulting in repeat multiple rounds of showers and storms.
PWAT values for the entire event range from 1.5 to 1.8 inches
which is around 2 SD`s above the normal. The concern for heavy
rain leading to some flooding or flash flooding is increasing. We
stayed close to NBM for temperatures with very little difference
seen in the multiple data sets.

.LONG TERM...(Thursday through Monday)
Issued at 315 PM CDT Mon May 23 2022

On Thursday into Thursday night, models show a surface low and
associated cold front pushing on through the PAH forecast area.
Scattered showers and thunderstorms will continue through the day
Thursday into Thursday evening, then lingering showers will taper
off southwest to northeast Thursday evening and overnight. Depending
on the speed of the upper low and trof, we may see some lingering
showers into Friday across our far eastern counties.

Another cool down can be expected Thursday with the clouds and rain
and the passage of the cold front.  Highs Thursday will be in the
lower to middle 70s, with lows Thursday night in the middle to upper
50s.  Friday and Friday night will see similar highs and lows.

A surface high off to our east and weak upper level ridging over the
middle Mississippi and lower Ohio valleys will give us dry
conditions through the weekend and into Monday.  Winds will shift
back to the south by late Friday night, so highs on Saturday will
climb into the lower 80s, with lows Saturday night only dropping
into the lower to middle 60s. Highs by Monday will be back into the
upper 80s.

&&

.AVIATION...
Issued at 559 PM CDT Mon May 23 2022

Quite a challenge for the 00z Tuesday WFO PAH TAF issuance. A weak
zone of channeled vorticity in the inflection point of weak
ridging to the southeast and slightly curved and tighter cyclonic
flow from southwest to east central Missouri has been producing
low to middle level VFR ceilings (and MVFR ceilings near KSGF)
this afternoon. This is a little more progressive than the high-
resolution models had been depicting by 00z Tuesday.

Had to go a little more pessimistic with the cloud cover and
ceilings with this forecast issuance as the flow from the systems
in the southern/central Plains and the Gulf of Mexico combine
forces to develop a zone of warm advection from southwest to
northeast across the WFO PAH TAF sites in the 12z-18z time frame
on Tuesday.

With that in mind, had to increase the coverage of cloud cover
significantly overnight and adjust ceilings downward from VFR to
MVFR during the day on Tuesday as a lower stratus deck develops
and expands northward through the day on Tuesday.

There is still some uncertainty with the lowered ceilings during
the daytime hours on Tuesday. Will see what the upper air guidance
from the 00z soundings indicate with respect to the
timing/coverage of stratus tomorrow.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

UPDATE...Smith
AVIATION...Smith



Area Forecast Discussion

National Weather Service Blacksburg VA

 924 PM EDT Mon May 23 2022

.SYNOPSIS...
A stalled front to our south will be the focus for rain tonight into
Tuesday. Another low pressure system arrives by Thursday with
more showers and storms.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 900 PM EDT Monday...

   Flood Watch issued for excessive rain tonight.

A mid- and upper-level ridge will continue to spin off the
southeast coast through Tuesday. At the surface, high pressure
will move over the northeast corner of the US, then wedge south
into the Carolinas tonight into Tuesday. Low level and surface
flow will bring relatively cool dry air (dewpoints in the mid
50s) southward, while the mid- and upper-level flow pushes warm
moist air northward. With these two air masses intersecting over
the region, insentropic lift will keep overcast conditions and
rain in the area into Tuesday.

With the wedge in play, Tuesday`s daytime temperatures (in the
60s) will run around 10F-15F cooler than normal. Very little
diurnal change in temperatures are expected. Have lowered
minimum temperatures a few degrees based on current trends in
observations and the latest gridded LAV and RAP guidance.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 100 PM EDT...

Rain will be in the process of tapering off from west to east
on Tuesday night. Rain showers will likely remain into Wednesday
morning for areas east of the Blue Ridge. Cooler air arrives
Wednesday as the weak low pressure system pulls eastward and
high pressure begins to wedge south. A combination of both of
these features will enhance and lock in the cold air wedge for
our region, featuring a northeast breeze, considerable
cloudiness and drizzle.

Wedge remains in place through Thursday, but weakens/erodes as
high pressure begins to slide into the northern Atlantic and
deep southerly flow aloft begins to increase ahead of the next
strong system moving into the middle Mississippi River Valley.
Regardless, some showers and clouds are likely to remain
throughout Thursday. With the stable cooler air in place, not
expecting any thunderstorms throughout this period.

Temperatures on Wednesday will be the coolest for the entire
week with many locations struggling to reach the 70s. Slightly
warmer on Thursday as the wedge tries to erode. Overnight lows
remain in the low to mid 50s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 115 PM EDT Monday...

Much larger uncertainty arrives for this coming Memorial Day
weekend. Guidance is widely varied with the progression of the
system on Friday, with some guidance completely clearing the
area for a mostly clear weekend, while others keep rain and
clouds around for most of the weekend with a closed low
meandering through. This does not give much confidence in the
forecast for Friday and beyond. Will be keeping the weekend
mostly dry on this forecast update, considering the drier
outcome has been modeled a bit more consistent, but still way
too far from certain to make any definitive statement on what
will occur this weekend.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 900 PM EDT Monday...

Expecting widespread IFR to LIFR ceilings and MVFR visibility
due to rain and fog overnight. Rain will start to taper off in
the mountains west of BCB/ROA after 12Z/8AM but cigs/vsbys will
stay low and not lift to MVFR until after 18Z/2PM.

Winds overall will run northeast to east at 5-10kts. Some gusts
to 25kts possible at LYH/DAN but for short windows. Thunder
chances are limited and likely south of KDAN so no mention in
the TAFs.

Extended Aviation Discussion...

Stalled front to our south will maintain cloud cover across the
region through at least Thursday morning with daily chances for
showers. This will result in prolonged sub-VFR conditions.

On Friday the Mid Atlantic region and Carolinas will be back in
the warm sector with a lower probability of precipitation and a
much better chance of VFR flight conditions.

The models are in poor consensus for the weather pattern for
Saturday. For now the forecast is dry.

&&

.HYDROLOGY...

   Flood Watch issued for excessive rainfall.

Combination of good isentropic lift and upslope will produce 1
to 3 inches of rain across southwest Virginia, northwest North
Carolina and southeast West Virginia. Already 1.0 to 1.5 inches
of rain from the mountains of northwest North Carolina north
to Bluefield and east into the New River Valley and across the
southern Blue Ridge.

00Z soundings at RNK measured 1.42 inches or precipitable water
with 1.68 inches at GSO. These are well above the 90th
percentile of climatology and close to the maximum values for
this time of year. Models showed nearly 2.0 inch precipitable
water values being lifted into the central and southern
Appalachians thanks to a low level jet perpendicular to the
ridges focusing from the southern Blue Ridge in the evening,
gradually to the Blue Ridge north of Roanoke late tonight
through 12Z/8AM.

Some locations, especially in in the northwest North Carolina
mountains and foothills had localized heavy rain Saturday or
Sunday. This spots will be particularly susceptible to flash
flooding. Several rounds of moderate rain with local heavier
rates up to 2 inches per hour are possible.

Main stem rivers can handle all of the runoff. But
tributaries, small streams and creeks, poor drainage and urban
areas are more likely to experience flooding.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Flood Watch until 8 AM EDT Tuesday for VAZ009-012>017-022>024-
     032>035-045.
NC...Flood Watch until 8 AM EDT Tuesday for NCZ001>003-018-019.
WV...None.

&&

$$
SYNOPSIS...RCS
NEAR TERM...AMS/RCS
SHORT TERM...BMG
LONG TERM...BMG
AVIATION...AMS/RCS
HYDROLOGY...AMS