Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/24/19
Area Forecast Discussion
National Weather Service Cleveland OH
925 PM EDT Thu May 23 2019
.SYNOPSIS...
A cold front will drop south across the area this evening. High
pressure from the northern Plains will build east across the
region on Friday. A warm front will lift north on Saturday then
sink south again on Sunday keeping the weather across the region
warm but unsettled through the weekend.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
The sky cleared out nicely with sunset and cold front is just
about through the forecast area at this time. Temperatures
dipped into the 60s across the north but remain in the 70s in
the south. Cooler temperatures will follow through the night.
Since thunderstorm threat moved south and east of the area,
removed chance for precipitation overnight. Otherwise, no other
major changes.
Previous Discussion...
Mixed layer CAPES running 500-1000J/kg across the area with the
most unstable air just to our southwest. High resolution
forecasts show this instability growing northeast into the
southern and southeastern counties and then shifting southeast
as the front moves through. Also watching the area of cu
development which so far has been capped but shows the most
unstable air. The HRRR continues its trend of not really
developing convection in the area through the evening. Don`t
completely trust it however so for the late afternoon and early
evening will continue with chance pops there. Dry elsewhere.
Overnight and Friday high pressure builds in. Friday night
models show the front returning as a warm front, driven north by
low pressure moving into the western lakes. Models show
increasing mid level rh across the area in the isentropic lift
of moist southwest flow. Will have chance pops showers
developing/drifting into the area from the north, mainly after
midnight. Highs friday from the upper 60s north to mid 70s
south.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
We will have a very Spring like day on Saturday and most of the
weekend with a deep southwesterly flow both at the surface and alot
up to 500 mb. A mid level shortwave will move across the upper Great
Lakes region and an embedded impulse will be move through the west-
southwest flow at 500 mb Saturday afternoon. Moderate instablilty
along with plenty of low level moisture and deep shear through the
mid levels will support at least the potential for some severe
weather. Given the uniform shear wind profile, linear form of storm
development with strong damaging wind gusts and large hail will be
the main hazards expected. The Storm Prediction Center has the
entire area in a Day 3 slight risk outlook which looks reasonable at
this time. It appears the greatest threat time for active weather
will be late Saturday afternoon through mid evening. Storms will
lose their punch later Saturday evening and Saturday night.
A frontal boundary will sag southward into Ohio late on Sunday.
South of the boundary will destabilized with a warm and humid
airmass. Additional strong to maybe some severe storms could be
possible again south of the boundary Sunday afternoon given the
westerly shear and instability. The front clears through the area
Sunday night with slightly cooler and drier air late Sunday night
into Monday.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
The frontal boundary drifts back northward as a warm front Monday
night with a risk for scattered showers and isolated storms if we
get a little low level trying to nose in across western Ohio. Mid
level heights rise on Tuesday with warm southwest winds. Warmer and
humid air moves back in with highs in the middle 80s and the threat
for some scattered convection in the late afternoon and evening. A
stout looking mid level shortwave will move through the Midwest and
Great Lakes Region sometime Wednesday or mid week. Timing on this
feature will make a difference if we have a severe weather threat or
not for Wednesday or Wednesday evening. At this time, we will
mention at least the threat for more stormy weather mid week and
warm and breezy weather. An upper level trough will try to start
building across the Great Lake Region by the end of the week with
slightly cooler weather.
&&
.AVIATION /00Z Friday THROUGH Tuesday/...
A cold front continues to push east across the area at this time
and will move east of the area overnight. A couple thunderstorms
developed south of Youngstown but they will continue to move
east away from the area. Cumulus cloud field appears to be
diminishing as more stable air from Lake Erie moves south over
the region. This should keep threat for showers or thunderstorms
at a minimum. Once front moves through the area, VFR will
prevail through the rest of the forecast period. Winds will
diminish as well with the passage of the cold front.
OUTLOOK...Non-VFR possible in thunderstorms Saturday and Sunday.
&&
.MARINE...
Westerly winds increased this afternoon over the lake and Small
Craft Advisories were issued for 20 to 25 knots winds and gusts up
to 35 knots. Winds will shift to more northwesterly late this
evening and over night with a decrease to 10 to 15 knots. Weak high
pressure will move over the lake Friday morning with light and
variable winds. Southeasterly winds will return Friday night into
Saturday morning with a warm front moving across the lake. Winds
will shift and increase Saturday afternoon up to 20 or 25 knots.
Small Craft Advisories may be needed again on Saturday. A cold front
will drift southward across the lake on Sunday and shift the wind to
northwesterly. High pressure will give a break in the weather for
the lake on Monday with lighter winds and waves. Strong low pressure
will move across the upper Great Lakes region on Tuesday and
Wednesday with gusty winds for Lake Erie. South-southwesterly winds
may approach 20 to 25 knots again and Small Craft Advisory
conditions may be needed again Tuesday into Wednesday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 5 AM EDT Friday for LEZ142>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/Lombardy
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Lombardy
MARINE...Griffin
Area Forecast Discussion
National Weather Service Dodge City KS
1107 PM CDT Thu May 23 2019
...Updated Aviation...
.SHORT TERM...(This evening through Friday)
Issued at 302 PM CDT Thu May 23 2019
Plentiful moisture, frontal boundary and upper level disturbance
will lead to widespread thunderstorms, some severe, through the
midnight hour. Surface based storms, which may be tornadic, will
be confined to the warm front zone over south central Kansas, with
elevated hailers to the north and west. On Friday the effective
frontal boundary will be undergoing frontolysis, but there should
still be enough convergence for surface based storms in south
central Kansas; and some of these will likely be severe with
large hail and damaging winds. These storms may be south and east
of Barber county depending on the exact location of the front.
South central Kansas will have to be watched for additional
flooding given the heavy rains expected.
.LONG TERM...(Friday night through Thursday)
Issued at 302 PM CDT Thu May 23 2019
The pattern will remain active through at least Monday as another
shortwave trough slowly approaches. There will be chances for
severe storms somewhere across the plains each day. Mesoscale
boundaries will likely play an increasing role in storm mode as
often happens as we get deeper into the warm season.
A break in the wet weather can be expected from late Tuesday into
early Thursday in the wake of the upper level disturbance. This
system will push a cold front through western Kansas with drier
air.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1107 PM CDT Thu May 23 2019
Scattered convection will continue for a few more hours, with
locally heavy rain and reduced cig/vis. HRRR model shows
convection ending and/or exiting eastward out of SW KS by 12z Fri,
with dry conditions returning to the airports. Outside of
convection, winds will trend light NW overnight, before becoming
light and variable around sunrise Friday. After 18z Fri, modestly
gusty south/southeast winds will resume at all airports, averaging
10-20 kts. VFR will prevail daylight Friday, with afternoon
convection favoring areas south and east of DDC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 54 76 61 81 / 80 10 30 40
GCK 47 78 58 82 / 60 10 20 40
EHA 46 78 53 81 / 30 10 10 50
LBL 50 77 56 80 / 60 20 20 40
HYS 54 79 61 82 / 80 10 30 20
P28 63 75 65 82 / 70 50 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 AM CDT Friday for KSZ066-079>081-
088>090.
&&
$$
SHORT TERM...Finch
LONG TERM...Finch
AVIATION...Turner
Area Forecast Discussion
National Weather Service Hastings NE
631 PM CDT Thu May 23 2019
.SHORT TERM...(This evening through Friday)
Issued at 345 PM CDT Thu May 23 2019
Aloft: 12Z RAOB data/WV imagery and RAP dynamic tropopause
analyses cont to show the persistent Wrn trof/Ern ridge pattern
that has been locked-in for the last wk. This was maintaining SW
flow over the NEB/KS that will remain so thru tomorrow. A low was
over UT with a shrtwv trof mvg NE thru CO/NM. Spaghetti plots of
the last 2 runs of mdls are tightly clustered on this low heading
NE acrs WY into MT by 12Z/Fri...and then acrs ND into Srn MB
tomorrow. The shrtwv trof will head NNE acrs Wrn NEB into the
Dakota`s tonight.
Surface: The prvs cool front that mvd thru here was stationary
from MO-OK-NM. High pres was over SD. Wk low pres will form along
the front and move NE acrs NEB/KS tonight...forcing the front to
move back N as a warm front. A stronger low will form over WY and
move into the Dakota`s. A cool front will be associated with this
low...but it will remain over SD tomorrow...leaving the CWA in
the warm sector.
Today: persistent WAA has been occurring atop the cool air mass
in place...basically along the 850 mb front in Wrn/Cntrl KS. This
has resulted in persistent shwrs and a few tstms here and there.
The low-lvl jet will incrs to 45-50 kt tonight resulting in the
plume of rich 850 mb dwpts of +15C to advect N into the CWA...
along with strong WAA/convergence. This will support cont`d tstm
formation.
There is uncertainty on the Nrn extent on the Nrn extent of the
instability/CAPE sufficient to support svr hail. We already had 1"
hail reported near Lovewell Reservoir. So it appears we hv what
we need.
Svr tstm watch 220 is in effect for 5 of our 6 KS counties until
03Z. Hail will be the primary threat.
Tonight: Cldy with periods of shwrs/tstms. Can`t rule out some
svr hailers mainly over our KS counties. There are considerable
diff`s among the CAMs as to how tstms over KS might unfold...but
all of them hv multiple tstms and/or periods of tstms mvg NE acrs
KS. The Nrn extent of this activity could result in hvy rain amts.
Will maintain Flash Flood Watch for Jewell/Mitchell/Osborne
counties.
The 18Z NAM nest suggests enough tstms could initiate over KS to
form a sqln.
Rain/tstms will end from W-E after midnight.
Fri: Any lingering low clds at dawn will quickly exit. Sunny and
much warmer. Highs around 80F.
.LONG TERM...(Friday night through Thursday)
Issued at 345 PM CDT Thu May 23 2019
Pattern: The last 2 runs of global mdls are in good agreement
with the EC and GFS ensemble means that the persistent Wrn
trof/Ern ridge will cont thru Tue. Wed-Thu considerable spread
dvlps as the mdls suggest some chgs...with less of a Wrn trof
...more of a NE USA trof which would suppress the SE USA
subtropical high. The EC runs and the 00Z ens mean form a cut-off
low over CA with SW flow cont over NEB/KS. Due to the
uncertainty...fcst confidence decreases after Tue.
Aloft: Heights in SW flow will rise a bit over NEB/KS Sat-Sun and
become anticyclonic in response to a deep low dropping down the W
coast and into the Wrn trof. SW flow will cont thru Tue. The low
will round the base of the trof thru the Desert SW Mon-Mon night.
The mdl consensus is that it weakens into a trof as it crosses
NEB/KS Tue night. Present indications are that low heights will
cont into Wed in the wake of the trof.
Surface: The low over the Dakota`s Fri eve will mv into ON Fri
night...allowing the cool front to sink into NEB/KS. This front
will become quasi-stationary acrs KS Sat-Sun...but as pres begins
falling in the lee of the Rckys...this front should lift N as a
warm front late Sun. This front will become stationary from SW-NE
Mon as one or more lows mv NE along the front. This front should
finally mv E of the CWA by Tue with wk high pres building over the
Cntrl Plns Wed.
Temps: Near to slightly abv normal Sat-Mon. Then cooler than
normal Tue-Wed.
Rain: Can`t rule out a few shwrs/tstms each day thru Tue...but
the best chance will currently appears to be Sun night. Too much
convective uncertainty and too many tstm chances to get into the
details this far in advance. Please follow SPC outlook for more.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday)
Issued at 624 PM CDT Thu May 23 2019
Showers and thunderstorms will continue to move through the
terminals for the next few hours. Ceilings will be IFR and even
LIFR as some of the precipitation moves through the area. Later
tonight the clouds will start to clear out.
&&
.HYDROLOGY...
Issued at 345 PM CDT Thu May 23 2019
Precip amts hv been hvy acrs N-cntrl KS over the last 7 days...
with 2-4". More hvy rain is psbl tonight. Flash Flood Watch will
cont as posted. The S Fork of the Solomon Rvr is running high...
at or abv action stage. It will not take much to result in Flash
Flooding or minor river flooding.
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...Flash Flood Watch through Friday morning for KSZ007-018-019.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...Flash Flood Watch through Friday morning for KSZ007-018-019.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...JCB
Area Forecast Discussion
National Weather Service Goodland KS
605 PM MDT Thu May 23 2019
.MESOSCALE DISCUSSION...
Issued at 548 PM MDT Thu May 23 2019
As was indicated earlier, storm intensity has increased from
earlier as elevated CAPE has also increased. This should last for
another hour or two before the storm intensity begins to weaken as
the next round of storms begin to develop.
Water vapor imagery continues to show a corridor of moisture in
the same location as earlier in the day, lowering confidence that
storms will spread over the forecast area from the west. What may
be more likely is storm activity increases east of the CO border,
forming more of a line that spreads east.
Effective shear will be even stronger this evening, which gives
concern that the hail threat will be even greater for the next
couple of hours before declining.
&&
.UPDATE...
Issued at 439 PM MDT Thu May 23 2019
So far hail reports have been on the low side of the severe
spectrum. As the afternoon progresses, effective shear will remain
the same however the elevated CAPE will increase. Therefore have
expanded the severe thunderstorm watch north to the Nebraska line.
Latest radar imagery is showing the next round of storm activity
already moving over Southern Colorado. This storm activity will
move into the forecast area around 6 PM MT. Storms should be in a
broken, if not solid, line as they move into the forecast area.
Storms will then spread east, exiting the Norton/Graham counties
around midnight. Once the storms form more of a squall line the
threat for the larger hail should diminish (golf ball size).
Confidence of flooding occurring is not quite high enough at this
time to issue a watch. Storms will continue to be moving quickly
through the evening. In addition there is a vary narrow swath of
rainfall amounts close to 1.5", while 6 hour flash flood guidance
is 2.2-2.4".
&&
.SHORT TERM...(This evening through Friday)
Issued at 1255 PM MDT Thu May 23 2019
18Z Water Vapor Imagery, RAP analysis indicated large closed low
circulation centered near the four corners region, with 1.5 pvu
fields indicating several smaller amplitude troughs moving through
the flow around it. At the surface, frontal zone was well to the
south of the area and generally ran parallel to the KS and OK
state line and then southwest through the Texas panhandle. Main
short term forecast concerns will center around thunderstorms and
precipitation amounts through tonight, followed by fog and near
freezing conditions tonight.
Thunderstorms have continued to redevelop in broad area of
isentropic ascent/WAA to the north of frontal zone. With
persistent moist flow over the front, storms continue to redevelop
and should continue to do so through the evening. Expect periods
of precipitation to continue through the evening hours, before
short wave trough moves over area, shifting winds to the west
aloft and ending any forced ascent around 06Z. Elevated
instability as per MUCAPES around 2000 J/KG are expected across
southeastern zones through the evening will help drive stronger
storms in this area. While storms not rooted in surface, elevated
shear profiles around 40 kts and aforementioned instability will
support a few severe hail storms south of a Weskan to Norton line
tonight. With saturated ground and several rounds of storms, am a
little concerned about flooding. However storms have been moving
fast enough to limit accumulations to under 0.2 of an inch each
round. While there is a high likelihood standing water may become
an issue tonight, quick storm motions should limit the flash
flooding threat and do not anticipate a watch at this point.
Persistent, near saturated easterly flow will maintain a low cloud
deck that should gradually lower into fog before midnight. As
system clears out storms, think there will be a 3 or 4 hour window
where a few pockets of dense fog may occur, before surface winds
shift to the west and airmass dries. With potential for
thunderstorms for a good part of this period, confidence too low
to issue any kind of fog highlight at this point in time.
As skies clear out around sunrise, expect to see temperatures dip
into eastern Colorado to around 34 bringing at least a small
threat for frost to form. Think there are a lot of things that
will have to be timed just right for this to become a widespread
problem, but this should be monitored.
On Friday, expect dry conditions, westerly winds and temperatures
rebounding to near 80 at many locations behind todays system.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MDT Thu May 23 2019
Overview: An active pattern characterized by a persistent upper
level ridge over the Deep South/Southeast and troughing aloft over
the Intermountain West/Rockies will prevail through early next
week. Long range guidance suggests that the ridge over the eastern
CONUS will relent /break down/ mid-week as an upper level low
digs southeast from the Northwest Territories/Nunavut to the Upper
Great Lakes and OH Valley.
Sat-Tue: A series of shortwaves will round the base of the trough
over the Intermountain West and eject northeast across the High
Plains in this period. Meanwhile -- southerly flow on the western
periphery of the ridge over the Southeast/Deep South will maintain
rich low-level moisture advection from the western GOMEX into
portions of the Southern/Central Plains. In such a pattern, expect
above normal chances for convection and episodic severe weather.
Although the greatest potential for convection will likely be
during the aft/eve hours (climatology) -- convection will remain
possible during the overnight and early morning hours.
Wed-Thu: At this time, long range guidance indicates that
confluent flow aloft will prevail over the Rockies/High Plains by
mid-week -- suggesting at or below normal chances for
precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 548 PM MDT Thu May 23 2019
VFR to IFR conditions forecast for the TAFs. Main concern will be
timing the ceiling category changes during the first 6 hours of
the TAF. At this point, looks like KGLD will raise to VFR after
the second round of storms move east of the site. However KMCK
will fall to IFR then raise back to MVFR behind the second round
of storms. What is concerning is that there is not a clear
distinction of whether the ceiling will increase to MVFR for KMCK
or remain at IFR. Due to a lack of confidence as far as which way
to go, decided to remain with the consensus for the TAF.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
MESOSCALE...JTL
UPDATE...JTL
SHORT TERM...JRM
LONG TERM...VINCENT
AVIATION...JTL
Area Forecast Discussion
National Weather Service San Francisco Bay Area
908 PM PDT Thu May 23 2019
.SYNOPSIS...Mainly dry conditions are forecast through Saturday,
along with continued cooler than normal temperatures.
Unseasonably cool and unsettled conditions are forecast to develop
later in the weekend as a system drops in from the north, with
scattered showers and isolated thunderstorms possible on Sunday.
Dry weather should return by Memorial Day, but temperatures will
remain cool into early next week.
&&
.DISCUSSION...As of 9:05 PM PDT Thursday...An upper low is
centered over the Great Basin this evening while a vort lobe
rotates around the west side of the low and across Eastern
California. This vorticity lobe has been triggering isolated
shower activity over mainly the eastern edge of our forecast area
since mid afternoon. Showers recently developed over far eastern
Contra Costa County and are moving south into eastern Alameda
County. There have been reports of lightning and thunder, but
based on lightning detection networks, it appears that
thunderstorms are farther to the east over San Joaquin County.
Based on latest HRRR and the 00Z NAM, all shower activity should
end by late evening.
The upper low is forecast to move quickly off the the northeast
tonight and Friday. Thus, Friday is expected to be a dry day
under partly cloudy skies. Temperatures will remain cooler than
average.
A couple of weather systems lurking well to our north are forecast
to drop south late in the week and through the weekend. The first,
currently over British Columbia, is expected to move into
northeastern California by Friday night. Models keep precipitation
with this system to our north and east. A second, stronger,
system, currently located near the south coast of Alaska, is
forecast to follow closely behind the first. The models agree
that a cold upper low will dig south along or near the California
coast late Saturday night and Sunday, and perhaps directly over
the SF Bay Area on Sunday. This unseasonably cool and robust
system will likely generate scattered showers across our area on
Sunday and Sunday evening (showers could start as early as
Saturday night). In addition, there may be sufficient instability
for isolated thunderstorms on Sunday. Models indicate the best
potential for thunderstorms on Sunday will be across the southern
half of our forecast area, primarily from the South Bay southward.
Rainfall totals with this weekend`s system will depend on the
exact track of the system. The 00Z NAM shows the upper low center
tracking just offshore, and thus gives the system move over-water
trajectory compared to the 12Z ECMWF. Thus, the NAM generates more
than twice the precipitation compared to the ECMWF. The 18Z GFS
QPF is similar to the wetter NAM. If the ECMWF were to verify,
precipitation totals would mostly be below a quarter inch, but the
00Z NAM shows precipitation totals close to an inch in some
sections of Monterey and San Benito Counties. All models agree
that the heavier rainfall totals with the Sunday system will be
over our the southern portion of our area - mainly Monterey and
San Benito Counties.
The Sunday system is forecast to be unseasonably cold, with the
NAM forecasting snow levels to drop as low as 4000 feet. The
National Blend of Models (NBM) is more conservative with snow
levels, maintaining levels above 5000 feet on Sunday. Once again,
much will depend on the exact track of the upper low. If the low`s
cold core tracks over or very close to our area, we could see snow
accumulation on the higher peaks in the Santa Lucia Mountains of
Monterey County on Sunday. And it`s not out of the question that
snow could fall as low as the highest peaks in the Bay Area (e.g.,
Mount Hamilton). Temperatures on Sunday are forecast to be as
much as 20 degrees below normal.
The upper low is forecast to move well off to the southeast of
our area by Monday. Thus, dry weather is expected to return by
Memorial Day. Temperatures will warm slightly on Monday, but still
remain well below normal.
Although temperatures are forecast to climb close to normal by the
middle of next week, there doesn`t appear much evidence from the
longer range models of any significant warming trend. In fact,
some longer range model solutions show an upper low retrograding
from the Great Basin over California and bringing more shower
chances later next week.
&&
.AVIATION...as of 4:44 PM PDT Thursday...Low clouds have stayed
in along the coast south of San Francisco including the MRY Bay
Area terminals. Some afternoon cumulus was forming in the SFO Bay
Area with convection limited to the higher terrain of the East Bay
and the Santa Lucias. Less winds tonight will allow low clouds to
spread into SFO and OAK and the North Bay valleys tonight but
well after the airport evening rush.
Vicinity of KSFO...Becoming MVFR after 09Z. West to southwest
winds 12-14 kt through 04Z.
SFO Bridge Approach...Similar to KSFO. Possibly less clouds late
tonight compare to KSFO and KOAK.
Monterey Bay Terminals...Clearing not expected this afternoon. MVFR
cigs lowering to IFR after 05Z.
&&
.MARINE...As of 8:39 PM PDT Thursday...Gusty winds gradually
decrease late tonight and early Friday as low pressure over the
Nevada moves east. Gusty northwest winds will redevelop over the
coastal waters Friday night through the weekend as another low
moves inland over the Pacific Northwest into the Great Basin. A
large northwest swell will subside but remain moderate through the
end of the week and into the weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM
SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm until 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Rough Bar Advisory for SF Bar until 3 AM
SCA...SF Bay from 9 PM until 3 AM
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: W Pi
MARINE: W Pi
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...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Friday Evening)
Issued at 324 PM CDT Thu May 23 2019
This afternoon, the mid level trough was observed across northern
Utah with a notable perturbation on water vapor lifting across
western Kansas. Coverage of showers and thunderstorms is beginning
to expand across western Kansas at the current hour with the
anticipation of these cells organizing into line segments as the
atmosphere becomes increasingly unstable further eastward into south
central and portions of north central Kansas. In addition to our
focus out west, we are also monitoring a warm front positioned from
the Kansas and Oklahoma border through southeast KS to south central
MO. While models are vary some on the northward progression this
afternoon, most short term guidance lift the front in the Ottawa,
Dickinson, and Morris county area by 6 PM this evening. The latest
runs of the HRRR and RAP are indicating the potential for some
initial cell development ahead of the western Kansas convection
within the warm sector south of the front or in vicinity during the
late afternoon and early evening. These supercells may be more
discrete and given the low level effective helicity increasing to
near 200 m2/s2 at this time, the threat for a few tornadoes is
possible in addition to large hail and damaging wind gusts. These
cells are expected to lift north and east during the early evening,
merging with the line of convection entering north central Kansas
after 9 PM.
The strong low level southerly jet coupled with >2000 J/KG of MUCAPE
suggest the strongest updrafts within the line may produce damaging
wind gusts and large hail. Storm mergers should deter the tornado
threat later in the evening, however cannot be completely ruled out.
Latest several runs of the RAP, HRRR, and HREF are hinting at
minimal forward progression overnight with the heaviest
concentration of rainfall remaining over north central Kansas. These
areas may be subject to the highest rainfall amounts with forecast
totals from 2 to 3 inches through Friday morning. Locally higher
amounts up to 5 inches are possible. Further south and east towards
much of northeast and east central areas, storms are expected to
gradually weaken in these areas, therefore 1 to 2 inches is the more
likely scenario. Based on the 2 to 3 inches stretching towards far
northeast areas, have decided to expand the Flood Watch to include
areas near the Nebraska border, Jackson, and Pottawatomie counties
for tonight.
Overall trends have the convection clearing north and east Friday
morning with a break in precip expected during the afternoon. As the
warm front reaches the Nebraska border tomorrow, much of the area
warms to the lower 80s with dewpoints potentially reaching 70
degrees by late afternoon. As the upper trough shifts towards the
North Dakota area by late afternoon, a mid level jet max lifts over
the plains with focus for development along a southwest to northeast
oriented boundary. Given the high instability and strong bulk shear
values up to 50 kts, severe storms are likely with all modes
possible, especially heavy rainfall through the overnight hours. For
tomorrow afternoon and evening, the focus area for heaviest rainfall
appears to bisect the CWA, from Dickinson county through Marshall
county, along with areas south and east.
.LONG TERM...(Saturday through Thursday)
Issued at 324 PM CDT Thu May 23 2019
Focus in the extended remains in the heavy rainfall and severe storm
potential from Saturday through Tuesday. Mean southwesterly flow
aloft coupled with several perturbations ejecting into the central
plains enhances the flooding potential, especially given that some
areas have received in upwards of 10 inches of rain since the
beginning of the month.
On Saturday, a boundary is progged to be positioned somewhere over
the state with indications for development along the boundary in the
afternoon, becoming more widespread in coverage in the evening
hours. Models are still differing on position of the boundary and
therefore where the heaviest rainfall axis occurs is still in
question. Confidence however remains moderate that portions of
central Kansas will see the best chance for scattered severe storms
and the heaviest rainfall. Surface based convection is more probable
given the lack of inhibition and expansive instability. Effective
bulk shear is not as high, but still supportive of supercells with
all hazards being possible. As storms congeal overnight, a line of
storms is likely as they progress across over most of the CWA late
Saturday night.
A similar scenario occurs Sunday night with the best pops currently
over north central Kansas. Activity spreads eastward over much of
northeast Kansas Memorial Day afternoon and evening as the main cold
front arrives. As the cold front surges through Tuesday morning,
there is finally a break in precip with a cooler and drier airmass
in place on Tuesday. Thereafter, upper ridge tries to build over the
Pacific Northwest with another closed low turning across the
southwest. Models differ on the strength of the upper ridge and
whether the closed low has an impact on the central plains after
Wednesday. Kept low chances throughout the week given the GFS is
still showing scattered storms in the area. Temps during the
extended are near normal in the mid and upper 70s for highs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 637 PM CDT Thu May 23 2019
MVFR cigs are expected until the frontal boundary moves to the
north of the terminals and winds shift to the south which will
occur in the 09Z-13Z time period. Scattered tsra is also expected
at MHK after 02Z and at TOP and FOE around 06Z. LLWS still
expected with southeast surface winds and them winds from the
southwest near 1500 ft increasing to 40 kts through 12Z. Scattered
showers and tsra are expected through 18Z. Additional development
possible near the end of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Friday morning for
KSZ008>012-020>024-034>037.
&&
$$
SHORT TERM...Prieto
LONG TERM...Prieto
AVIATION...53