Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/26/19
Area Forecast Discussion
National Weather Service Cleveland OH
1011 PM EDT Sat May 25 2019
.SYNOPSIS...
A cold front will slowly sag south across the area late
tonight, pushing just south of the area Sunday afternoon. The
front will remain between the southern Great Lakes and Ohio
valley through Monday before lifting north through the area
Monday night into Tuesday, remaining north of the area through
midweek. An unsettled weather pattern will remain over the
region much of next week.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Little change with this mid evening update. Will have quiet
conditions through the early morning hours. Will be watching
convection upstream reach western OH by morning. Expecting some
showers/thunderstorms to work across the area in the morning
and early afternoon with a second round confined more to the
southern counties possible for late afternoon/evening. Previous
discussion follows.
The unofficial start to Summer has brought record heat and
severe storms this holiday weekend. Afternoon temperatures
managed to reach the upper 80s and lower 90s. We were able to
mix out very well with some slightly drier dewpoints working
down to the surface. CAPE values have reached between 2000-3000
J/KG, downdraft CAPE values have reached up to 1500 J/KG, Bulk
shear values are about 45 to 50 knots. There is also a MCV
moving out of Indiana into Ohio this afternoon which all points
to an active afternoon with a broken line of severe convection
developing and moving eastward. Storm motions will be fast given
the mid level flow. The main threats for these storms will be
damaging wind gusts of 70 mph and large hail up to ping pong
size possible. The latest runs of the HRRR and 4KM NAM Nest
have finally came into some decent agreement with the timing and
placement of the storm potential through the early evening.
Most of the severe storms should be out of our local CWA by 8 pm
this evening.
A cool front will sag southward into the area by Sunday morning.
Another ripple of energy and disturbance will move along in the
westerlies early Sunday morning and may interact with the front.
Guidance does show additional storms, some strong, may be
impacting western Ohio by 9 am Sunday and moving into central
Ohio by late morning and midday. Some of these storms may become
severe and there is a marginal to slight risk for severe weather
across portions of central Ohio. Damaging winds and hail will be
again the main threat. Temperatures will be cooler north of the
southward front. The front will move through the entire area by
Sunday evening with slight drier and cooler weather moving in
temporarily.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Frontal boundary will dip south of the area on Monday allowing for
slightly cooler temperatures especially near the lakeshore with
northerly flow. The frontal boundary will return north Monday
increasing the chances for showers and thunderstorms mainly in the
evening. Rain chances come down to only a slight chance for Tuesday
due to residual moisture over the area, however dynamics will be
insufficient for much coverage.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Conditions become more favorable for convection on Wednesday as a
shortwave trough advances into the Great Lakes region from the
plains. This feature has a slow eastward progression and will
support a SW flow and moisture stream from the gulf with dew points
in the mid 60s and highs in the 80s. The best upper level dynamics
are displaced to the northwest, however there will be some enhanced
divergence aloft. The trough will weaken and Thursday and swing east
of the area Friday with cooler and drier conditions expected late
week.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
This round of showers/thunderstorms have passed the terminals as
of 00Z/Sunday. VFR conditions in their wake for the remainder of
the evening. A cold front will be sinking southward early Sunday
morning. Early day showers/thunderstorms will be possible, with
the best coverage/second round during the peak heating of the
day across southern terminals. CAK/MFD/FDY will include VCTS for
those chances. MVFR ceilings possible as we initially generate
cumulus later Sunday morning. Non-VFR within any convection that
develops too. Winds will be southwest tonight, but veer to the
north across the far northern terminals after about 18Z and
through 00Z Monday far south.
OUTLOOK...Non-VFR possible for periods of time through Thursday,
primarily centered around rounds of convection.
&&
.MARINE...
Several pieces of low pressure will impact the region today through
Tuesday night with a frontal boundary lifting north and south of the
lake multiple days. Southwest winds of 10-20 knots on the lake this
afternoon will lead to choppy conditions and 2 to 4 foot waves on
the east end for a few hours this evening. Otherwise a weak cold
front will settle south of the lake early Sunday morning with high.
pressure building in behind and bringing generally light wind
conditions for Sunday. Easterly winds develop on Monday ahead of a
warm front that will lift north across the lake Monday night. This
will lead to a brief period of elevated water levels across the
western basin of the lake. However speeds may not be high enough to
cause anything more than minor flooding issues with the extremely
high water levels. Southwest winds increase Tuesday into Wednesday
and a Small Craft Advisory may be needed for portions of Lake Erie
on Wednesday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Griffin/Oudeman
NEAR TERM...Griffin
SHORT TERM...Jamison
LONG TERM...Jamison
AVIATION...Oudeman
MARINE...KEC
Area Forecast Discussion
National Weather Service Des Moines IA
609 PM CDT Sat May 25 2019
.DISCUSSION.../Tonight through Saturday/
Issued at 328 PM CDT Sat May 25 2019
Vigorous holiday weekend into the middle part of next week.
Generally west turning southwest flow aloft during this time with
several shortwaves tracking across the region before the large
upper level system moves through by Tuesday night into
Wednesday. Utilized a blend of the HREF, HRRR, and RAP tonight
into Sunday and then a mix of the GFS/ECMWF.
Tonight through Sunday...instability continues to build over
southern Iowa as the boundary drapes across central Iowa from west
to east. Dewpoints are in the middle to upper 60s south of the
boundary with good moisture transport into southern Iowa and
precipitable water values range from 1.0 to 1.5 inches. The pwats
are well within the 90th percentile for climatology on May 25th.
Corfidi vectors are fairly close in line with the storm movement
and thus training storms are possible tonight into early Sunday
morning. Soil moisture content is high and rainfall rates tonight
should be intense at times and so confident to keep the Flash
Flood Watch in effect tonight into early Sunday morning. Much of
the precip looks to confined to the southeast by 10-12z Sunday and
out of the forecast area by 13-14z. The severe threat tonight
remains limited due to the lack of significant low-level shear and
helicity present. Main concern is with the isolated elevated hail
potential with the decent mid-level lapse rates and LCL heights
around 750-1000m AGL. Plus, the severe threat looks limited to
sunshine and should decrease past 01z tonight.
Sunday night into Monday...Surface high pressure takes over for
the rest of the day Sunday and into much of the evening Sunday
before a warm front associated with a surface low pressure over
the High Plains to enter the state by around 06z Monday. Shortwave
energy pushes into western Iowa during this time and continues to
press east-northeast into about 12-15z Monday morning. Yet
another round of moderate to heavy rain potential along with the
isolated severe storms threat from 06z to 15z Monday, but the set
up looks to be central to northern portions of the forecast area.
Steady moisture transport into northern Iowa and with the best
moisture convergence and highest precipitable water in this
location, the heavy rain potential is a concern for flash flooding
as well as river flooding.
The warm front remains draped across the state Memorial Day into
early Tuesday with the GFS slightly further north than the ECMWF
in the placement. Still, there should be a break in the
convection from the morning storms moving east before
redevelopment late in the afternoon. This should allow for plenty
of time for destabilization to occur south of the front, engulfing
at least two-thirds of the forecast area. Uncertainty remains how
far north the boundary stalls and thus the location of greatest
severe threat. The latest models have trended slightly further
south and suspect the severe threat will do as well. Surface based
CAPE increases to 2500-3500 J/kg and deep layer shear ranges from
35 to 50 knots from east to west. The low level shear is
sufficient for rotating updrafts and the 0-1km helicity along the
warm front tops out at around 200 m2/s2 by 00z Tuesday. Certainly
Monday afternoon and evening appear to be the best threat for
widespread severe storms over central Iowa and something to
continue to monitor for any holiday festivities.
Tuesday through Saturday...
Yet more rain and severe thunderstorm threat with the low pressure
system and associated cold front/dryline on Tuesday into Tuesday
night. The GFS and ECMWF are in fair agreement with the track of
the surface low but the GFS is slower in bringing it eastward.
Thus, timing of the low is critical to any severe weather threat
on Tuesday. The rest of the work week looks less active with the
GFS suggesting a weak shortwave to impact the region by Friday.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 609 PM CDT Sat May 25 2019
VFR conditions for northern TAF sites through the period. concerning
KDSM and KOTM (especially KOTM)isolated to sct TSRA will produce
local MVFR conditions which will impact KOTM the most. Heavy rain,
large hail and strong wind possible with storms.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Sunday morning for IAZ074-075-081>086-
092>097.
&&
$$
DISCUSSION...Podrazik
AVIATION...FAB
Area Forecast Discussion
National Weather Service Quad Cities IA IL
837 PM CDT Sat May 25 2019
...HYDROLOGY UPDATE...
.SYNOPSIS...
Issued at 234 PM CDT Sat May 25 2019
What was a dreary start to the day with plenty of overcast and
scattered rain showers has turned into a mix of clouds and sunshine
as of 2 PM. The MCV that was responsible for this has moved
further east, and was producing showers and thunderstorms across
the northern Ohio River Valley as of this writing. Temperatures
across our neck of the woods currently range from 75 in Sterling,
to 83 in Vinton. Dewpoints were in the lower to upper 60s, making
it quite humid as well. The warm front that moved across the area
yesterday evening stretched from southeast Nebraska to northern
Wisconsin, allowing the warm, humid air mass from the Gulf of
Mexico to continue building into the area.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 234 PM CDT Sat May 25 2019
Main concerns of the short term period are our chances for showers
and thunderstorms this evening through Sunday morning.
Latest model analysis shows the warm front will remain north of the
area this evening, keeping us locked in the unstable, warm and
humid air mass. Several CAMS such as the NAMnest and HRRR
continue to show scattered showers and thunderstorms developing
across the area around 5-7 PM, similar to how things evolved
yesterday. There is a potential for some thunderstorms to become
severe, and the latest SPC update has expanded the marginal risk
north to the Highway 20 corridor. The primary threats
thunderstorms this evening will be large hail and damaging winds
with plentiful moisture, steep mid level lapse rates (giving us
plentiful CAPE of 2000-3000 J/kg) and the presence of deep
vertical shear to work with. Can`t rule out an isolated tornado,
but the threat is lower today given the warm front is further
north, along with the lack of lower-level shear and helicity.
Later this evening, attention turns to how developing convection
over eastern Kansas and northwest Missouri evolves as it moves north
and east. Models continue to remain in agreement of keeping this
convection and the main axis of heavy rainfall around the Highway 34
corridor southward where best moisture advection is focused.
Therefore, not planning any changes to the timing or position of
the current Flash Flood Watch with this afternoon`s forecast
package. With very high PWATs still in place, showers and storms
will have no trouble producing locally heavy rainfall amounts of 1
to 2 inches. As mentioned in the previous discussion, it won`t
take much to generate water problems given the saturated soils and
recent rounds of heavy rainfall (Latest CPC analysis shows the
entire area with a soil moisture ranking profile in the 99th
percentile).
For Sunday, ongoing rain and thunderstorms will diminish and exit
the area by morning as advection decreases and the LLJ shuts off. By
late morning and early afternoon, expecting sun to begin breaking
out from a leftover overcast deck, especially north of I-80, as weak
subsidence builds across the Great Lakes. This should make for a
mild, yet humid day across the area. Currently have forecast
afternoon highs ranging from the middle 70s to near 80, with
dewpoints climbing into the lower to middle 60s.
.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 234 PM CDT Sat May 25 2019
Unfortunately, the threat of showers and thunderstorms will continue
to remain each day through at least mid next week. This also
includes a threat for severe weather.
Sunday night and Monday...
Attention turns to how convection that is progged to develop over
northern Kansas and central Nebraska evolves Sunday night.
Weak area of low pressure is expected to develop over western
Nebraska early in the period, which will help transport rich
theta-e air across the Midwest Sunday night towards the warm
front, which will be draped across northern Iowa and southern
Wisconsin. Any activity from this convection will reach our neck
of the woods late Sunday night into early Monday. Latest guidance
shows the highest QPF of around 1 to 2 inches is expected to
track along the warm front, which looks to stay north of the
Highway 20 corridor. This will add to uncertainties in how river
forecasts will evolve into late next week, especially along the
Mississippi River.
The Storm Prediction Center has our area outlined in a slight risk
for severe thunderstorms Monday afternoon and evening, which will be
heavily dependent on how showers and thunderstorms evolve and
persist during the morning. However, will need to watch how a
shortwave trough evolves as it progresses across the area Monday
afternoon and evening, which looks to be the primary driver for
convection. If clouds are able to break and build additional
instability, showers and storms could develop in the warm sector,
which should be fully established across the area. Damaging winds
and large hail are the primary threats with storms at this time.
In addition, the threat of heavy rainfall with any thunderstorm remains.
Tuesday & Tuesday night...
Models vary with respect to the warm front position to begin this
period. Latest GFS and ECMWF allow the warm front to sag a little
south towards the I-80 corridor by 12z Tuesday, while the CMC and
NAM keep the front further north into Minnesota and Wisconsin. For
now will go with a blended approach, which would keep chances of
morning precipitation with the front around the Highway 20
corridor northward. Areas that don`t see rain showers during the
morning will be locked under mostly cloudy skies with plenty of
moisture advection occurring overhead.
Severe weather looks to be a concern once again Tuesday afternoon
and evening ahead of a developing cold front approaching the area
from the west. Of concern is agreement in the latest guidance of
a 50-60 kt mid-level jet ejecting over the region, which would
give us high low and mid level wind shear to work with. When
combined with CAPE progged between 2000-3000 J/kg, storms that
develop along and ahead of the front would be capable of producing
all modes of severe weather. This period will continue to be
monitored, so stay tuned for the latest information.
Wednesday on...
Main cold front is progged to move through the area Wednesday
morning, which should give us a brief reprieve of wet weather and a
disconnect from Gulf moisture through the end of the work week. The
GFS and CMC remain a little aggressive with the last runs in
bringing a weak shortwave across the area Friday, while the ECMWF
remains completely dry.
Guidance shows active weather returning by Saturday, but confidence
on this materializing this far out is low. Look for changes to this
period with the next forecast package.
As we head into late May and early June, current trends snow near
to below normal temperatures with above normal precipitation
across the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 622 PM CDT Sat May 25 2019
Showers and storms will increase in coverage across the area
tonight accompanied by periods of MVFR to IFR conditions, as
a cool front sags through the region. A few severe storms are
possible this evening with large hail and damaging winds, which
could impact BRL and possibly MLI. The precipitation will
dimnish Sunday morning with a return to VFR conditions.
&&
.HYDROLOGY...
Issued at 832 PM CDT Sat May 25 2019
No significant changes noted in the forecasts this evening. During
this active pattern through early next week it is important
to remember that river forecasts do not include rainfall beyond
24 hours. Therefore, any changes in the distribution or amounts
of rainfall will lead to significant changes in the forecasts.
Previous discussion Issued at 1117 AM CDT Sat May 25 2019
Rainfall from Friday and Friday night ended up being well less
than had been forecast. Heavy rain had been expected from
northeast Missouri through north central Illinois, but that area
was largely missed Friday night, which has led to lowered
forecasts for most forecast points with this morning`s forecasts.
Some tributary rivers did have forecasts drop enough to allow the
cancellation of the warnings.
On the Mississippi River, the most noticeable changes were to the
Rock Island LD15 gage and downstream due to the much lesser inputs
from the Rock River. Later expected precipitation (mainly from
Monday and Tuesday) will likely cause the forecasts to rise higher
than the current forecast levels, but the degree of the rises will
be dependent on what areas will receive the rains and those rains
will likely not be included in the forecasts until Monday and
Tuesday`s forecasts.
Locations that have the highest chance for seeing widespread
rainfall today will be far southern Iowa into west central
Illinois and southward, while more scattered activity is expected
to the north through Sunday morning. Showers and storms are still
possible on Sunday as well, but not looking for widespread heavy
rains locally, so much of the area is likely to see almost 2 days
without soaking rains. Sunday night into Monday is the next chance
for widespread heavy rains, but the current track of the complex
of storms is expected to be centered into northern Iowa,
Minnesota, and Wisconsin. So it will have an impact on rivers, but
maybe not as big of an issue for flash flooding. Then Tuesday and
Tuesday night the entire area has a threat for heavy rain.
Overall, the miss of last night`s rain is significant in the
forecasts as it should lead to a lower chance to reach the high
levels that have been advertised this past few days. That being
said, with chance for rain every day still through Tuesday night,
a lot can change in the forecasts as crest level expectations are
still highly dependent on the forecast rains over the next 5 days.
We urge people with interests in the rivers to stay in tune with
the latest information.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flash Flood Watch until 7 AM CDT Sunday for Des Moines-Henry IA-
Jefferson-Keokuk-Lee-Louisa-Muscatine-Scott-Van Buren-
Washington.
IL...Flash Flood Watch until 7 AM CDT Sunday for Bureau-Hancock-
Henderson-Henry IL-McDonough-Mercer-Putnam-Rock Island-
Warren.
MO...Flash Flood Watch until 7 AM CDT Sunday for Clark-Scotland.
&&
$$
SYNOPSIS...Speck
SHORT TERM...Speck
LONG TERM...Speck
AVIATION...McClure
HYDROLOGY...Brooks/McClure
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
638 PM CDT Sat May 25 2019
.Discussion...
Issued at 308 PM CDT SAT MAY 25 2019
Our active weather pattern will continue this afternoon into the
overnight hours, but some uncertainty does exist within both the
possible periods of weather. For this afternoon the main concern
will be possible strong to severe storms over northern Missouri in
an area of surface convergence ahead of a quasi-stationary boundary.
There is currently a capping inversion around 6kft which has created
a solid stratocumulus deck over the area and my actually help
inhibit additional heating and chances to break this cap. CAMs
continue to indicate that there will be just enough lift in the mid
levels and warming on the surface to help stretch this layer and
help break this cap around 4-5pm. We are still leaning towards this
occurring as surface temperatures have gotten into the upper 70s and
dewpoints are now just below 70 which was needed for this to occur.
If the cap does break this afternoon we will have around 2500-3000
J/kg of MLCAPE and 50kts of effective bulk shear. Soundings indicate
that supercells are possible and large hail (up to golf balls) and
damaging winds will be the main threat. The DCAPE values will be
near 1200 J/kg so this does indicate strong downbursts are possible
with these storms. This activity will be mainly limited to HWY 36
and north with only some isolated showers and storms possible south
of that due to no real forcing mechanism to focus on.
The next threat for the area appears to be a possible QLCS that is expected
to form out over TX/OK/KS and slowly propagate up into our area
around midnight. There are many factors that could change the storm
mode and severity of this line as it pushes through, but the HRRR
does tend to have favorable low level shear to keep this system
balanced and possibly a wind threat with potential mesovorticies
along any surges. While the severe weather threat is there with this
line the main impacts may actually be flooding as a quick 1-2" is
possible with this system. Our flash flood guidance has recovered
some this afternoon but most of the area in the flash flood watch
has less than 2" for 1 and 3 hour periods. The western side of the
KC Metro and down along I-35 corridor and north central Missouri
have the lowest guidance and would be the main area of concern
overnight. Models are also hinting at a strong LLJ forming early in
the morning that may help initiate new convection or at least
provide enough isentropic accent to form showers and storms over
eastern KS and western Missouri around sunrise and into the late
morning. This would not be favorable for the area and would be a
possible flood setup so this will need to be watched as a
possibility as the evolution of the possible QLCS is observed this
evening.
A shortwave will exit the Rockies Sunday night causing a low
pressure to form with a warm front extending into NW Missouri on
Sunday afternoon. This could redevelop some showers and storms, with
some being strong to severe, Sunday evening into the overnight
hours. This low pressure system will track to the north Monday
setting up the stage for severe weather Tuesday. The timing of the
cold front pushing through on Tuesday afternoon is what makes this
setup worth watching. We will be in the warm sector all day with no
real morning MCS threats to kill our heating chances. A strong upper
and mid level jet over eastern KS will provide plenty of shear with
instability present. The details will reveal themselves as we get
closer to the event.
Finally! A few dry days look possible Wednesday afternoon through
Friday late morning giving us at least a small window to dry out.
Unfortunately this window will not last long as troughing and
another wet pattern sets up going into next weekend and early next
week.
&&
.Aviation...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 638 PM CDT SAT MAY 25 2019
Isolated thunderstorm development is possible over the Kansas
City Metro TAF sites with scattered thunderstorms and MVFR
conditions developing over northern Missouri which will be more
of an impact for KSTJ through 06Z. After 06Z, expect a north/south
line of thunderstorms in eastern Kansas to move east into western
Missouri and impact all TAF sites with MVFR conditions and
possible IFR conditions in heavier precipitation. Expect MVFR
ceilings by 10Z improving to VFR by 15Z and winds will
predominately southerly 6-10kts, outside of convection.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Flash Flood Watch through Sunday morning for KSZ025-057-060-
102>105.
MO...Flash Flood Watch through Sunday morning for MOZ001>008-011>017-
020>024-028>031-037-038-043-044-053.
&&
$$
Discussion...Barham
Aviation...32/Otto
Area Forecast Discussion
National Weather Service Hastings NE
704 PM CDT Sat May 25 2019
.SHORT TERM...(This evening through Sunday)
Issued at 418 PM CDT Sat May 25 2019
A weak disturbance is moving across the Central Plains this
evening and tonight. A couple rounds of thunderstorms are
possible. The first round has begun in extreme southeast Colorado
and southwest Kansas. This activity is expected to grow and evolve
cluster of storms that moves through north central Kansas and
portions of south central and southeast Nebraska.
Watching the higher-resolution models, the HRRR/NAMNest/NAM and
RAP all show this evolution from western Kansas northeast into
north central Kansas and further northeast into Northeast Kansas
and southeast Nebraska. The models hint at a couple of rounds with
the initial wave moving through this evening and a secondary
round during the overnight hours. How far this activity may spread
northward is the question. Feel the best chance for thunderstorms
will be along and south of I-80...especially south for areas south
of the Nebraska/Kansas state line. With the abundant MUCAPE and
MLCAPE of over 2000 J/KG and 40-50 kts shear, severe storms are
possible...mainly for areas along and south of the NE/KS Border.
These storms could produce large hail up to golf ball size and
damaging winds to 60.
A Flash Flood Watch continues from 7pm tonight to 7am Sunday for
north central Kansas. The ground is saturated and any additional
rain...even another inch or so could cause some flooding and rises
in rivers.
.LONG TERM...(Sunday night through Saturday)
Issued at 418 PM CDT Sat May 25 2019
The active period continues through Tuesday as the upper trough
sits off to the west and multiple disturbances round the base of
the trough until it moves through early in the work week. The next
disturbance moves ejects northward out of the trough Sunday
afternoon. The weak boundary that is draped across the region is
expected to lift northward tonight and early Sunday putting the
whole region in the warm sector. Thunderstorms are expected to
develop in the western High Plains in Kansas Sunday afternoon and
spread northward. Most of the area is in the SPC Day 2 Enhanced
and think that is fairly good with abundant instability and shear.
Low level helicity also increases over northwest Kansas and into
north central Kansas and parts of southwest and south central
Nebraska. With this, a tornado or two is not out of the question.
This activity is expected to lift northward across the heart of
the forecast area during the overnight hours bringing the best
potential for additional rainfall to much of the forecast area.
May see another flood watch for this time period Sunday.
The main disturbance will rotate around the base of the trough
and begin to eject to the northeast for Monday. This disturbance
and upper wave will tighten up the frontal boundary and will bring
another potential for severe thunderstorms as the surface low
moves across the area. The better chances will be along and north
of I-80, but cannot rule it out across the whole area with ample
shear and instability.
Highs through the Holiday weekend will be in the 70s to low 80s.
The upper low will finally move east enough to push the surface
front into eastern Nebraska and Kansas sometime on Tuesday. The
trend has been for this to slow, so the current severe risk which
is just east of the area, could move westward if the front slows.
Something to watch for Tuesday.
Wednesday and Thursday look quieter with the Plains under
northwest flow for a brief period. Temperatures will cool back
down slightly, but most importantly there is a lull in
precipitation.
By the end of the work week, southwesterly flow will return and
another disturbance will cause the chance for showers and
thunderstorms to return for the end of the week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 642 PM CDT Sat May 25 2019
Ceilings will be the toughest to forecast as the two terminals
will be on the northwestern fringe of convection that could move
through this evening and into the overnight. Confidence is quite
low, and could potentially vary quite a bit from hour to hour. The
overall trend into Sunday should be for MVFR ceilings, however.
There is a better chance for storms on Sunday evening, just past
00Z, moving in from the west.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...Flash Flood Watch through Sunday morning for KSZ005>007-017>019.
&&
$$
SHORT TERM...Billings Wright
LONG TERM...Billings Wright
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Goodland KS
935 PM MDT Sat May 25 2019
.UPDATE...
Issued at 932 PM MDT Sat May 25 2019
Strong/severe storms have moved out of the area. A few areas may
see a shower or isolated thunderstorm overnight.
UPDATE Issued at 758 PM MDT Sat May 25 2019
With all major strong/severe convection having shifted east of
the CWA...have cancelled the Severe Thunderstorm Watch. Locales
could still see a shower or an isolated thunderstorm over the next
couple hours.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 245 PM MDT Sat May 25 2019
Tonight-Sunday night...general idea is for convection to approach
the far southern portions of the forecast area by 22z-23z with
models either increasing coverage to the northeast which would flirt
with our east through southeast zones or straight north (RAP model)
through early to mid evening. Convection may redevelop and intensify
after midnight generally east of a Joes to Goodland and Russell
Springs line (experimental HRRR most aggressive with more subtle
qpf output from other models) lifting northeast and exiting the
area while weakening by sunrise Sunday morning. Widespread stratus
expected with some fog possible within a few hours of sunrise.
For Sunday through Sunday night strong to severe thunderstorms are
possible across the far southern forecast area as early as 18z
before lifting north and increasing in coverage and intensity during
the afternoon. The entire forecast area is under an enhanced risk of
severe weather per SPC day 2 outlook. Convection should come to an
end around midnight before a strong mid level dry slot moves in from
the southwest putting an end to precipitation chances.
Low temperatures tonight range from the upper 40s to low 50s in far
eastern Colorado to the mid/upper 50s in Norton and Graham counties.
High temperatures Sunday should range from the mid and upper 70s
east of the CO/KS border where low clouds may linger for much of the
day to the low 80s along and west of the CO/KS border. Low
temperatures Sunday night range from the mid 40s to around 50 in the
west, near 60 in the east.
Monday...its possible for a few strong to severe thunderstorms to
develop in the mid to late afternoon hours along and east of a line
from near Trenton to Colby and Oakley near a NAM model dryline. The
GFS model continues to have this feature well east of the forecast
area. For now will keep forecast dry per coordination with
surrounding offices. Southerly winds increase in the afternoon with
gusts in the 30 to 40 mph range expected. High temperatures in the
mid 70s to mid 80s. It appears the most likely scenario at this time
is for some showers and thunderstorms to move into the far north and
northwest portions of the area after midnight as an upper level low
pressure area moves toward the area from west central Colorado. Low
temperatures range from the low to mid 40s west, mid 50s east.
Tuesday...general idea is for the upper low to continue moving
northeast into central Nebraska during the day with some wraparound
rain showers during the day across the northwest 1/2 of the area.
Afternoon temperatures will be much cooler with readings ranging
from the upper 50s to mid 60s in far eastern Colorado to the mid 70s
in Norton and Graham counties. Some wrap around rain showers
possible north of the interstate Tuesday evening. Low temperatures
in the upper 30s to low 40s west, upper 40s east.
.LONG TERM...(Wednesday through Saturday)
Issued at 245 PM MDT Sat May 25 2019
Wednesday...dry weather currently expected. High temperatures in the
60s to around 70. Low temperatures in the 40s.
Thursday...precipitation chances return to the forecast as some
moisture associated with a weather disturbance moves across the area
from the west-southwest. High temperatures in the 70s. Lows range
from the mid/upper 40s west to mid 50s east.
Friday...some weak disturbances move across the area from the
west/southwest supporting spotty chances for thunderstorms. High
temperatures in the mid 70s to low 80s. Low temperatures in the mid
40s to around 50 west, mid 50s east.
Saturday...little change from Friday with a chance of afternoon
thunderstorms. High temperatures in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 515 PM MDT Sat May 25 2019
Both terminals will be on the north side of a frontal boundary
for much of the forecast period. This front will transition over
the region after 12z Sunday...increasing the chances for
precipitation.
For KGLD...VFR skies thru 06z Sunday...then MVFR ceilings/vcsh
thru 09z. From 09z-15z IFR ceilings around OVC004-008 with IFR
fog from 12z-15z. Conditions increase to MVFR from 15z-20z
Sunday...then from 20z onward...VFR with vcsh. Will keep as such
due to low confidence in timing so far into the forecast
period...but will trend to vcts/tsra with the next issuance/two.
For KMCK...VFR skies thru 06z Sunday...then MVFR ceilings from
06z-12z w/ vcsh. IFR skies around OVC005-009 from 12z-19z...then
a quick increase to MVFR with some patchy fog from 12z-15z.
Finally VFR from 22z Sunday onward. Will keep as such due to low
confidence in timing so far into the forecast period...but will
trend to vcts/tsra with the next issuance/two.
Winds...a general ESE direction for both taf sites around
5-15kts. Strongest winds will occur before 06z Sun...and after
20z-22z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...AW
SHORT TERM...99
LONG TERM...99
AVIATION...JN
Area Forecast Discussion
National Weather Service Indianapolis IN
1143 PM EDT Sat May 25 2019
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 336 PM EDT Sat May 25 2019
An active weather pattern will remain in place with chances for
showers and thunderstorms and above normal temperatures for much
of the next week.
&&
.NEAR TERM /Overnight/...
Issued at 942 PM EDT Sat May 25 2019
Surface analysis this evening shows high pressure in place across
the deep south with warm and humid SW flow streaming across
Indiana. A cluster of thunderstorms had developed over SE Iowa and
NE Missouri. Skies across Central Indiana were continuing to clear
as convection related to the heating of the day continued to
diminish.
850mb-300mb model thicknesses suggest propagation of the Iowa
thunderstorms to reach Central Indiana late overnight. HRRR is
also in agreement...pushing showers/storms across the northern
parts of the forecast area after 09Z...persisting until nearly
14-15Z. Time heights and forecast soundings suggest ample moisture
and lift...thus have trended pops higher overnight than the
previous forecast.
Also given the expected clouds and rain...trended overnight low at
or above the model blends.
&&
.SHORT TERM /Sunday through Monday Night/...
Issued at 336 PM EDT Sat May 25 2019
Forecast focus is on timing for rain and storms for the remainder
of the holiday weekend. Unfortunately models are still not in good
agreement on timing of QPF over the area, so medium confidence is
going to be the best this forecaster can offer. That said, for
those with outdoor plans contingent on dry weather, here it goes.
An upper wave moving through during the late overnight/early
morning hours will have rain ongoing across much of northern and
central Indiana as Sunday morning begins. Expect this first wave
to move off to the east and allow for a few dry hours, starting
late morning (9-11 am) and ending in the early afternoon (1-3
pm), depending on your location. In the hourly forecast, show
this in the form of PoPs of 20-30 percent during the "most likely
to be dry" hours.
The potential problems with this timing is where the front sets
up. Fairly confident on the timing of the upper waves (early
morning, then arriving early to mid afternoon), but not confident
on the exact location of the front. This could again serve as a
focusing mechanism for convection and increase severe potential,
and it could legitimately set up anywhere in Indiana depending on
what happens with the first wave of convection in the early
morning.
Sunday night the upper wave will move out and convection will end,
bu the front possibly moving north through the area during the
day on Monday could prompt some showers and storms for the
holiday. Those chances are lower at this time due to uncertainty
regarding the frontal position, but the upper forcing looks far
less impressive than Sunday afternoon.
All of these waves over the same general area raises the concern
for flooding, and will have to monitor this closely going forward.
At this time not expecting a widespread threat, so will forgo any
flood headlines.
High tempertures Sunday will be highly dependent on cloud cover
and the aforementioned precipitation that develops. Went toward
the middle of guidance in the lower to mid 80s, with high humidity
as well. Monday should be a few degrees warmer.
&&
.LONG TERM /Tuesday through Saturday/...
Issued at 336 PM EDT Sat May 25 2019
Temperatures will run slightly above normal through the long term,
and an active weather pattern with a trough over the western U.S.
spitting out shortwaves that will bring thunderstorm chances to
central Indiana Tuesday night through Thursday. The pattern will
become flatter and more progressive toward the end of the week.
&&
.AVIATION /Discussion for the 260600 Tafs/...
Issued at 1142 PM EDT Sat May 25 2019
Mainly VFR conditions will be expected this taf period in between
periods of showers and thunderstorms.
VFR conditions are expected to continue the next few hours. SHRA
and TSRA are expected in the area after 09Z-10Z. Brief MVFR to
IFR conditions will be possible with any thunderstorm.
Showers and Storms over Central Illinois are expected to propagate
to central Indiana after 09Z. Models then suggest this short wave
will depart the area near 12Z before another short wave arrives
after 15Z. Ample moisture and forcing appear present. Thus will
trend toward VFR conditions with prevailing SHRA/vcts after 20Z-
21Z. Again...any shower or storm that strikes a taf site may
result in brief IFR conditions.
Sundays short wave should depart by 22Z-24Z...and a return to VFR
will be expected within the wake of the any storms overnight.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...Puma
SHORT TERM...CP
LONG TERM....CP
AVIATION...JP
Area Forecast Discussion
National Weather Service North Platte NE
632 PM CDT Sat May 25 2019
.SHORT TERM...(This evening through Sunday night)
Issued at 334 PM CDT Sat May 25 2019
A few light rain showers and isolated thunderstorms remain possible
for tonight. Any thunderstorms that do develop are expected to
remain sub-severe, however, still capable of producing small hail
and gusty winds. Overnight lows are expected to fall into the upper
40s to mid 50s. Active weather is expected for Sunday with
thunderstorms possible through the day. Any thunderstorms during the
day are not expected to be severe at this time. Instability will
increase late in the day Sunday which will increase our severe
weather potential heading into Sunday night. Models are indicating
that a long-lived convective line of storms will move through during
the overnight hours Sunday into Monday morning. Large hail and
damaging winds will be the main focus through the night.
.LONG TERM...(Monday through Saturday)
Issued at 334 PM CDT Sat May 25 2019
We will see quite an active weather pattern from Monday through
Wednesday as a series of disturbances are expected to move through
the Central Plains. This will bring rain and isolated thunderstorm
chances across the area through Wednesday. Strong to severe
thunderstorms will be possible on Monday as a warm front across
central Nebraska will become a focus for thunderstorm development.
Heavy rain will also be a concern from Monday to Wednesday. Forecast
rainfall totals through Wednesday morning range from 1 to 2 inches
across northern Nebraska. Forecasted rain along with saturated soils
from previous heavy rainfall has increased our concern for flooding
across this area.
Dry and quiet weather will take over the region on Wednesday and
much of the day Thursday. There are a few isolated chanced of rain
and thunderstorms late in the day Thursday and Friday, however,
confidence remains low at this time. For temperatures, the week will
begin warm on Monday. Slightly cooler temperatures will move in on
Tuesday, with the coolest temperatures across the northwest
Sandhills. Wednesday will see highs in the 60s followed by 70s for
Thursday, Friday and into the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 632 PM CDT Sat May 25 2019
VFR conditions this evening transitioning to MVFR and eventually
to LIFR at KLBF by Sunday morning.
Weak convection moving across the far northern Panhandle currently
which most CAMs including the HRRR have a decent handle on. This
driven by weak convergence and flow around the Black Hills and
higher terrain to the west. Low level moisture is lacking in this
area and wouldn`t expect continuation past sunset and not looking
like it will make it to KVTN. Lower cloud deck moves in overnight
in the south in association with a larger area of convection to
the south and northward moving warm front. Have introduced light
fog at KLBF Sunday morning based on short range model soundings
and larger scale pattern association. Better TSRA chances after
the end of the forecast period.
&&
.HYDROLOGY...
Issued at 334 PM CDT Sat May 25 2019
River levels have been relatively steady on Elkhorn river at
Atkinson and Ewing today. Near Atkinson, the river is above minor
flood stage with the latest reading at 8.22 ft. A Flood Warning
remains in effect for west central Holt county through 7 am Sunday
morning. Elsewhere, a Flood Warning also remains in effect in
northern Brown County where water continues to overtop Pine Canyon
Dam on the Plum Creek. This warning goes into mid morning Sunday.
A Flood Advisory continues until 10 am Sunday for the Keya Paha
River in northeast Keya Paha and west central Boyd County. River
levels upstream, notably Wewela on the Keya Paha, have started to
go down thus the threat is expected to lower. Lastly, A Flood
Advisory remains in effect through 145 pm Sunday from the Cedar
River in southwest Wheeler County.
Looking ahead, storms and significant rainfall totals are possible
Sunday night through the first half of the week. A Flood Watch is in
effect Sunday evening through Tuesday afternoon. The heaviest
widespread rain is expected to occur Sunday night, Monday night, and
Tuesday. A lull in activity is expected during the daytime Monday.
Overall, total rainfall amounts of 1 to 2 inches are forecast with
locally higher amounts possible across the north central. The
additional rainfall will increase the potential for flooding due
to already saturated soils, increased runoff, and high water
tables.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Sunday evening through Tuesday evening for
NEZ004>010-023>029-094.
&&
$$
SHORT TERM...Thorne
LONG TERM...Thorne
AVIATION...Stoppkotte
HYDROLOGY...Roberg
Area Forecast Discussion
National Weather Service Marquette MI
635 PM EDT Sat May 25 2019
.SHORT TERM...(This evening through Sunday)
Issued at 415 PM EDT SAT MAY 25 2019
Water vapor imagery and RAP analysis show a shortwave lifting ne
thru northern Ontario. At the sfc, trailing cold front extends
across far se Lake Superior and eastern Upper MI. Latest SPC
mesoanalysis shows mlcape edging up toward 300j/kg ahead of the
front in a narrow zone btwn the front, which is now surging s due to
lake breeze assistance, and the edge of the Lake Michigan modified
air mass under ssw winds. Deep layer shear is on the order of 60-
70kt. Vis satellite imagery shows vigorous looking cu vcnty of the
southward surging cold front/lake breeze, and a few short-lived
-shra are occasionally appearing. Remains to be seen if any tsra
will develop in the next couple of hrs, but there may be too much
shear for the limited instability to get any storms going. Given the
instability/shear, if any storms do develop, a svr storm is
possible until front clears the area in the next few hrs. Behind the
front, gusty w to nw winds have taken hold under deep mixing, aided
by caa and incoming 3-4mb/3hr pressure rises. Wind gusts of 25-35mph
are common with some gusts to 35-45mph over the Keweenaw. Deep
mixing has allowed dwpts to crash in a corridor from around KLNL
toward KSAW. With temps mid 70s to around 80F, RH has plummeted to
25-30pct. Stratocu that has developed off to the w in ne MN/nw WI
under approaching 850mb thermal trof has struggled to spread all the
way across the cold/stable marine layer over Lake Superior, a
typical scenario for this time of year.
A few shra, maybe a tsra, will develop over the eastern fcst area
for the next couple of hrs until front exits. Otherwise, expect some
of the stratocu to the w to spread into the area this evening before
fading away during the night. Winds will remain gusty until the loss
of solar insolation. With winds diminishing and skies trending
toward mostly clear, some of the traditional cold spots may dip blo
40F tonight. Otherwise, 40s will be the rule for low temps.
On Sun, shortwave swinging across far northern Ontario will push an
associated cold front s across Lake Superior and into Upper MI
though front gets somewhat difficult to locate in the aftn due to
lake breeze development. Limited instability (mlcape under 100j/kg)
and evidence of a warm nose/weak capping inversion should prevent
any -shra development. So, not expecting anything more than sct
flattening cu on Sun, perhaps bkn cu vcnty the lake breeze
boundaries during the mid and late aftn. Will still be warm away
from lake moderation with highs in the low to mid 70s.
.LONG TERM...(Sunday night through Saturday)
Issued at 326 PM EDT SAT MAY 25 2019
After the passage of a cold front during the day Sunday, weak
surface high pressure centered near the Ontario/Manitoba border
Sunday night will keep conditions relatively quiet. A very weak
shortwave and some minor convergence at low levels is possible and
with a moist air mass in place the possibility exists to squeeze out
a few showers, mainly over northwestern Lake Superior. Essentially
the only model producing any rain over the central and eastern CWA
at this point is the NMM, but I opted to add some slight chance
POPs.
As a mid-upper level low slowly translates east through the inter-
mountain west Monday, a shortwave will push out ahead of it across
the Great Lakes. The main area of forcing for ascent has shifted
south a tad over the last few model runs, with rain crossing the WI
border Monday afternoon. Should move out to the east late Monday
night. QPF will be highest over Menominee County where >0.5" are
possible, with generally a widespread 0.2-0.4", and less than 0.1"
over the far NW.
CMC is out to lunch Tuesday morning with widespread rain remaining
through the morning hours while the deterministic GFS and ECMWF are
dry. However, with several GEFS members predicting some additional
shower activity, the slight chance to low end chance pops loaded by
the blend were mostly left alone for the time being. Tuesday night,
there is more agreement in a dry period, but as the low over the
western CONUS opens up and increases in eastward propagation speed,
it is expected to bring additional chances for showers and possibly
a few thunderstorms on Wednesday into Wednesday night. Timing and
QPF amounts will remain uncertain for the time being as model
agreement leaves a little to be desired.
Surface high pressure is expected to build back into the area behind
Wednesday`s shortwave and should yield drier conditions later Wed
night through Friday with some seasonally cool air expected to
filter in.
Models then show a nw flow trough and associated cold front moving
through, with this feature slowing from previous model runs. It now
appears more likely on Saturday into Sunday, bringing another round
of showers across the area and a reinforcing shot of cooler air.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 635 PM EDT SAT MAY 25 2019
Drier air flowing into the area will allow VFR conditions to prevail
at KIWD/KCMX/KSAW thru this fcst period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 415 PM EDT SAT MAY 25 2019
On Lake Superior, gusty westerly winds of 15-25kt, with gusts to
around 30kt, following passage of cold front will diminish tonight.
Late tonight thru Sun morning, winds will be under 15kt. Another
cold front dropping s across Lake Superior on Sun will bring a brief
period of stronger winds, affecting mainly western Lake Superior
where ne wind gusts of 20-30kt will be possible for a few hrs
following passage of the front in the late aftn and early evening.
Winds will then be under 20kt Sun night, lightest over the e half of
Lake Superior. NE winds may increase some on Mon, gusts to 20-25kt,
mainly over western Lake Superior. Winds should then be under 20kt
thru the middle of the week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
Dense Fog Advisory until 8 PM EDT this evening for LMZ248-250.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KCW
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
942 PM EDT Sat May 25 2019
.AVIATION...
The forecast of isolated showers in SW VA has worked out well this
evening, but the slight chance PoP will need to be extended
southward and a few hours later as radar shows some showers
developing in NE TN. The HRRR and RAP did well to depict this
development. Only PoP/Wx/sky grids will be adjusted as temps are
on the right track.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
DGS
Area Forecast Discussion
National Weather Service Omaha/Valley NE
619 PM CDT Sat May 25 2019
.SHORT TERM...(Tonight through Tuesday)
Issued at 325 PM CDT Sat May 25 2019
The main concerns in the short term focus around thunderstorms
intensity/coverage/rain amounts. The active southwest flow
pattern in the mid levels will remain in place through Tuesday.
A closed low will drop southward along the west coast through
Sunday night, move out into northern CO by early Tuesday and then
across parts of western and central NE through Tuesday night.
Day 1 SPC outlook shows a marginal risk of severe storms in our
southern zones through tonight. This seems reasonable. Because the
soil is already very wet in parts of the area and we expect at
least some storms tonight, will keep the flash flood watch in
place. Surface dewpoints south of the front are in the 70s across
KS this afternoon. That humid air should move up into southeast NE
and southwest IA Sunday.
Kept main thunderstorm chances across the southern half of the
forecast area tonight. Precipitable Water (PW) this afternoon are
an inch or higher across our southern zones, and that should
increase through Sunday. Surface high pressure in place over the
eastern Dakotas/MN/parts of IA and NE will build to the east
tonight and pressure will start to fall over the high plains.
This will cause southerly flow to increase with low level
convergence along the boundary. 20Z mesoanalysis showed about
2000 J/kg of CAPE for the lowest 100 mb mixed layer. Recent HRRR
and ESRL HRRR models suggest storms will increase in coverage mid
to late evening, then decrease after midnight, with another
potential round of showers/storms from around sunrise into mid
morning Sunday.
Storm chances the rest of the day seem lower, with an increase
toward Sunday evening into Sunday night. Timing will be difficult
beyond that, but it does look most active in the evening and
overnight.
Additional flash flood watches may be needed the next few nights
but will do these on a day by day basis.
.LONG TERM...(Tuesday night through Saturday)
Issued at 325 PM CDT Sat May 25 2019
Pattern remains Tuesday night and Wednesday, but then we SHOULD
get a bit of a break as the flow turns more zonal for Wednesday
night through Thursday. Storm chances will return for at least
parts of the area Friday through Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 615 PM CDT Sat May 25 2019
VFR conditions will prevail at KOFK/KOMA thru the fcst pd. At
KLNK, sct TSRA will begin lifting out of KS into SE NE later this
evening. Expect a few TSRA to move through KLNK sometime around
midnight. Improvement to VFR shortly after.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flash Flood Watch through Sunday morning for NEZ088>093.
IA...Flash Flood Watch through Sunday morning for IAZ080-090-091.
&&
$$
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...DEE
Area Forecast Discussion
National Weather Service Pendleton OR
818 PM PDT Sat May 25 2019
.SHORT TERM...Tonight and Sunday...made some changes for the
overnight reducing the amount of showers over the Washington
Cascades and then increasing them on Sunday. This due to models
wrapping moisture over central Idaho across central Washington
overnight and then into the Cascades early Sunday. The upper level
low dropping down the coast tonight will be into California on
Sunday. This is responsible for the convective showers this evening
over the eastern portion of the forecast area and the steady rain in
central Oregon. Sunday will again be convectively unstable for most
of the forecast area except the east slopes of the Washington
Cascades where the steady light rain is expected. Increased the
chance of thunderstorms over northeast Oregon and southeast
Washington from slight chance to chance Sunday afternoon as
instability will be a little better in this area.
&&
.PREV DISCUSSION... /issued 300 PM PDT Sat May 25 2019/
SHORT TERM...Tonight through Tuesday...A closed low spinning off
the Washington coast will travel south and will be centered near
Brookings, OR by midnight. A broad circulation will be present over
the western half of the U.S. through Memorial Day associated with
the large low pressure system. The cyclonic flow aloft and
increasing instability will make for a somewhat challenging forecast
over the next few days to pinpoint where showers and thunderstorms
will develop. Just about anywhere in the forecast area has at least
a slight chance of showers and thunderstorms. For tonight, a weak
wave will bring showers and isolated thunderstorms across northeast
Oregon and southeast Washington. SBCAPEs are around 500 J/kg from
the latest SPC`s Mesoscale Analysis, and the HRRR tracks one cell
southeast to northwest over the Blues and into the Blue Mountain
Foothills this evening. Dewpoints in most areas are in the 30s to
lower 40s, so the possibility of anything more than isolated
thunderstorms is slim.
The low will be located over northern CA on Sunday, and multiple
waves rotating around the low will bring showers and isolated
thunderstorms to the forecast area. Once again, just about anywhere
has a slight chance of thunderstorms and this was included in the
forecast. Thunderstorms are not expected to be strong or severe but
could bring frequent lightning and heavy rain. On Memorial Day, the
low will approach the four-corner states. This broad circulation
with multiple embedded waves will bring a chance of showers and a
slight chance of thunderstorms to the forecast area. By Tuesday,
the low will be far east and out of range, but a northerly flow
aloft will be present with lingering moisture and instability for
isolated showers and thunderstorms, mainly over southeast Oregon.
No wind concerns are anticipated in the short term, but there will
be occasionally breezy NNW winds on Sunday and Monday. The higher
peaks of the Wallowas, Elkhorns, Strawberries, and Cascades--mainly
above 7000 feet---will also have periods of snow this holiday
weekend. Wister
LONG TERM...Tuesday night through Saturday. Extended models have
some slight differences in the overall pattern. In general it
appears the Pacific northwest will remain in a weak trough pattern.
The result will be partly cloudy skies with daytime instability
producing scattered showers and thunderstorms mainly over the
mountains. Best chances will be central and northeast Oregon. 850mb
temps warming and will give highs in the 70s to lower 80s. No
significant winds expected through the period. 94
AVIATION...00z tafs. Scattered showers and isolated thunderstorms
for PDT ALW and possibly PSC through evening then decreasing.
Showers or a stratiform rain for YKM DLS RDM BDN associated with the
upper low offshore. This will diminish overnight. Winds 5-15kt
except 10-25kt DLS. Scattered showers and storms again Sunday. 94
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 69 50 74 / 30 30 20 10
ALW 50 72 53 76 / 30 40 20 20
PSC 55 75 55 83 / 20 40 20 10
YKM 50 68 52 80 / 20 60 10 20
HRI 51 73 53 80 / 30 20 20 10
ELN 46 65 49 77 / 20 70 20 20
RDM 40 64 45 70 / 80 40 40 40
LGD 44 67 49 67 / 70 70 30 30
GCD 43 64 47 66 / 60 80 40 30
DLS 49 73 55 80 / 20 20 20 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
91/91/91
Area Forecast Discussion
National Weather Service Pueblo CO
852 PM MDT Sat May 25 2019
.UPDATE...
Issued at 849 PM MDT Sat May 25 2019
Quick update to incorporate latest obs data as well as satellite
and radar trends. Added some patchy fog to portions of the eastern
plains overnight. Moore
&&
.SHORT TERM...(This evening through Sunday)
Issued at 316 PM MDT Sat May 25 2019
...Severe Weather expected across the eastern plains this
afternoon and again Sunday afternoon...
A severe thunderstorm watch is in effect until 9 PM for the far
southeast plains of Baca, Bent, and Prowers Counties. We`ve
already issued a few warnings and we expect a few more storms to
initiate along a convergence zone currently analyzed on GOES-16
(and surface mesonets) to be across the middle of Baca County
westward into eastern Las Animas County. South of the boundary
dewpoints are in the mid to upper 50s, which is a bit lower than
the high res models had been indicating for this afternoon. As a
result, surface-based CAPE will also be less than originally
expected, but we still expect 1500-2000 J/kg, enough for severe-
sized hail up to golf ball in size and potentially damaging
straight line winds to 60 mph. 0-6 km wind shear is still
excellent for supercells, and new storms should fire along the
boundary and more quickly northeast across Baca, Prowers, and SE
Bent Counties through 6-7 PM or so. Conditions across the rest of
our area are too dry for precipitation the rest of today and
tonight.
After the storms move into Kansas from extreme southeast Colorado,
we should be dry all night area-wide. We`ve been watching the
potential for patchy fog across Crowley and Kiowa Counties in the
moist upslope flow along the east side of the Palmer Divide
eastward into Kansas. The HRRR originally had it pushed west into
the COS metro area, but has recently backed off that solution.
Have included patchy fog into eastern El Paso, northern Crowley,
and Kiowa Counties after 3 AM. Convective outflow from storms in
Kansas would enhance the moist low-level flow, increasing fog
potential along the south and east side of the Palmer Divide, but
confidence in any fog making it to the I-25 corridor is low at
this time.
Sunday looks to be a repeat of this afternoon across our area,
including the potential for severe weather, albeit a little
further west and north than this afternoon. SPC has our far
eastern zones in an enhanced risk of severe weather Sunday
afternoon. As with today`s severe weather, the threat and impacts
depend mostly on how far north and west the low-level moisture can
get. For now the moisture looks to make it east of a line from
Kim to La Junta to Limon. The surface convergence zone behaves
much more like a traditional dryline Sunday afternoon, with good
southwest winds to the west along with warm/very dry air.
Dewpoints to the east of the dryline should reach the upper 50s. Convergence
along the dryline should initiate a few storms after 2 PM,
especially given the mid-80s temps at the surface that are
expected. Surface based CAPE values again support severe weather,
with 2500-3000 J/kg. 0-6 km shear also supports supercells as the
primary mode of convection, with 45-50 kts. Dryline-relative flow
and a good capping inversion at 700 mb means storms should be
fairly discrete as they move northeast off the dryline. Low-
level wind shear/SRH and a lack of a secondary boundary (other
than the dryline) means the threat of tornadoes is probably low.
The biggest impacts tomorrow will be large hail and damaging wind
gusts.
Aside from the severe threat, the mountains should see diurnal
convection Sunday afternoon into the evening with lightning and
gusty winds the main impacts. Some of the storms may survive the
trek east, but just an isolated chance across the Palmer Divide,
Raton Mesa, San Luis Valley, and the Wet Mountain Valley. High
temperatures will range from upper 70s to mid 80s across the
plains, to the low 70s in the San Luis Valley and upper Arkansas
basin, and upper 40s and 50s in the mountains.
.LONG TERM...(Sunday night through Saturday)
Issued at 316 PM MDT Sat May 25 2019
Storms that form Sunday afternoon should be moving east into
Kansas by late Sunday evening, and most areas should be dry
overnight into Monday. A potent late-season storm across
California will continue to move east throughout the day Monday,
and by midnight Tuesday the center of the storm should be across
the Utah/Colorado border. Ahead of the trough strong southwest
flow will continue over our area both aloft and at the surface,
resulting in another warm afternoon Monday, with convective
chances confined to the eastern San Juans and Sangre De Cristos.
Across the plains low-level moisture will be pushed well east into
Kansas so we do not expect any repeat of Saturday/Sunday`s severe
weather.
On Tuesday the trough moves across northern Colorado and into
Nebraska by Tuesday afternoon. Despite decent QG forcing throughout
the day, our area looks to be dry slotted, especially across the
plains. The trough does advect cooler air aloft, so despite the
dry low-levels, diurnal convection is possible across El Paso
County and across the mountains, with the primary impacts
lightning and gusty winds. Instability overall should be limited.
Late Tuesday into Wednesday as the trough moves further northeast
our area is under northwest flow. The ejecting surface low across
the central plains drags a cold front across eastern Colorado
late Tuesday, and it should clear our area early Wednesday. The
post frontal air is seasonably cool, and there is a fair amount of
cold advection at 700 mb throughout the day, resulting in below
normal highs for Wednesday. The COS metro area should struggle to
reach 60 degrees and the plains only in the mid to upper 60s. The
plains should remain dry behind the front, while once again with
good cooling aloft the mountains could see isolated showers during
the afternoon, with the best chances from the eastern San
Juans/La Garitas to the upper Arkansas Basin.
For Thursday and Friday yet another trough is positioned upstream
across the Great Basin, resulting in southwest flow aloft and a
continuation of afternoon thunderstorms across the mountains. 700
mb temps warm a bit on Thursday, then another warm another 4-6
degC on Friday, resulting a nice warming trend at the surface and
a return to more seasonable temperatures, even above normal by
Friday with mid 80s across the southeast plains. Enough low level
moisture should be in place across the plains for some of the
afternoon storms to survive the trek east out of the mountains and
off the Palmer Divide and Raton Mesa. Will keep low PoPs in place
to account for this each afternoon/evening. Instability remains
fairly limited so main impacts would be gusty winds and some
lightning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 316 PM MDT Sat May 25 2019
Quiet weather expected across the terminals through Sunday
evening, with VFR conditions expected and no precipitation. High
resolution models develop some fog along the east side of the
Palmer Divide, and early runs brought the fog into the COS metro
area, perhaps as far west as the airport. However, recent trends
have backed off so will remove the TEMPO group for fog. Evening
shifts will watch the trends, especially if convection to the east
can send a gustfront west up the slope of the Palmer Divide which
would increase the coverage and westward push of any fog that
develops. Otherwise expect drainage winds through mid morning and
no aviation impacts. By Sunday afternoon southeast to south winds
will once again increase at PUB and COS, gusting 20-25 kts. At
ALS expect similar afternoon winds as Saturday, with southwest
winds gusting 25 kts or so.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOORE
SHORT TERM...SCHLATTER
LONG TERM...SCHLATTER
AVIATION...SCHLATTER