Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/14/19
Area Forecast Discussion
National Weather Service La Crosse WI
1053 PM CDT Sat Jul 13 2019
.SHORT TERM...(This evening through Sunday)
Issued at 243 PM CDT Sat Jul 13 2019
Have left a slight chance of TSRA in nern IA and swrn WI where a
low-level moisture convergent boundary should be in place between
northerly flow and southwesterly flow east of the ridge axis. This
confluence is what assisted this morning`s TSRA as MUCAPE of ~2k
J/Kg was in place. This moisture convergence gradually lifts
northeastward overnight per RAP forecasts, thus low chances for
TSRA follow. Only wild card may be the convectively-induced
shortwave trough on ND/SD border at 17Z which will drop toward the
area. After midnight, this may be able to interact with the
boundary and mild MUCAPE to provide a bit more development than
currently forecast. Will follow trends seen in the observational
and model data to try and improve forecast overnight as needed.
.LONG TERM...(Sunday night through Saturday)
Issued at 243 PM CDT Sat Jul 13 2019
Focus through the upcoming week will be on heat/humidity and storm
chances.
Broad mid-level ridging will occupy the central US on Sunday. A more
dominant low-level southerly flow will develop along with some warm
advection in advance of a shortwave trough topping the ridge from
the Dakotas. Forcing through the day looks low, but can`t completely
rule out convection with any remnant MCVs that could provide a
local source of lift given available instability. Highs will reach
the mid 80s to low 90s.
Thunderstorm chances may increase late Sun/Sun night with the
approach of the shortwave. Model guidance varies somewhat on
evolution/timing, but convection associated with the wave may
spread out of the Dakotas/Minnesota Sunday afternoon approaching
the local area Sunday evening or night. Track of the wave and
general consensus of the high res models favors northern WI with
the highest storm chances, although will have to be wary of any
southward shift towards the higher instability/weakness in the
stronger cap to the south or shifts in the shortwave track, which
could result in more of the area being affected (towards I-90).
Heavy rain would be a primary threat with this activity given the
instability and deep moisture combo and potential for a modest LLJ
to refire convection along the outflow and nose of the LLJ
overnight. Deep layer shear will be a bit stronger (30-35 kts from
0-6 km) closer to the shortwave across northern WI, which may
allow for a severe threat, primarily wind, if an organized
convective system develops to the west. Will have to watch trends
carefully into tomorrow as the evolution becomes clearer, in terms
of timing and location.
On Monday, 925 mb temps of 26 to 29C and SW surface flow ahead
ahead of a front working east from the Dakotas may allow temps to
reach 90 for much of the area. That said, clouds/convection may
serve to keep temps lower, especially farther north.
Not much change is expected through the remainder of the week. Temps
will remain above average with NAEFS 850 mb anomalies of +1 to +2
sticking around into the weekend. Overall expect highs ranging from
the mid 80s to low 90s and lows in the mid 60s to low 70s
throughout this period based on consensus. However, the 13.12Z
indicates 925 mb temps near or above 30C late in the week, which
would support highs in the mid/upper 90s+ for parts of the area,
while the GFS brings a stronger trough into the area with cooler
temps during this time. If the warmer solutions verify, heat
headlines would be needed. Chances for convection will continue
off and on through mid-week, possibly impacting day to day temps.
As the stronger westerlies dip a little farther south heading into
mid- week, wind shear will tend to increase, which could support
more organized storms, although it`s far too early to have
confidence in convective/severe chances.
Next weekend, 12Z runs of the GFS/ECMWF indicate high pressure
building across the Upper Midwest but differ on the amplitude of
the mid level ridging and degree of warmth/storm chances over the
area. Thus, forecast confidence for next weekend is low.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1053 PM CDT Sat Jul 13 2019
The stationary front has remained south of the area this evening
and the convection that developed over South Dakota has
dissipated. The front should begin to move slowly back north
overnight as the low level ridging slides east through the Great
Lakes. The RAP is not showing any support for development along
the front as the low level moisture transport stays well off to
the west of the area. There had been some concern for convective
development Sunday afternoon over the Dakotas and Minnesota that
could have approached the airports Sunday evening. However, all
the models this evening have now backed away from this idea and
now show any convection remaining well northwest of the area. Will
have VFR forecasts for both airports with just some high level
clouds.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Baumgardt
LONG TERM...JM
AVIATION...04
Area Forecast Discussion
National Weather Service Des Moines IA
1057 PM CDT Sat Jul 13 2019
.DISCUSSION.../Tonight through Saturday/
Issued at 204 PM CDT Sat Jul 13 2019
Synoptic Overview:
Weak short-wave and associated surface boundary across the northern
Plains and Upper Midwest shifting east will return to mainly zonal,
with weak ridge over the High Plains later this afternoon. H5 flow
to remain benign for most of the weak, remaining zonal in nature
with a few days where weak ridging develops. A few embedded short
waves possible toward the middle end of the week. In the Gulf, TS
Barry has slowed down but is still working its way inland through
Louisiana, getting close to hurricane strength. With overall weak mid
to upper level flow, difficult to predict exactly how any remnant
tropical depression will track and how it will interact with any
surface high pressure over the mid-latitudes.
Today and Tonight:
Main feature of interest for this afternoon will be the boundary
across northern Iowa and southern Minnesota on the backside of the
passing short-wave trough. The struggles of the CAMs this month
continue today, with this morning`s convective complex along the low-
level jet persisting much later into the morning than guidance
otherwise favored prior. GFS/NAM have pinpointed a concentrated axis
SBCAPE between 3000 and 4000 J/kg on the south side of this
boundary with daytime insolation, and CAMs through 13z also try to
depict this. However, the lingering cloud cover from the late
morning convection across the north may hinder the significant
destabilization anticipated prior. With no substantial AVA or any
other feature promoting large scale subsidence, clearing may be
difficult this afternoon. Even if there is some clearing, minor
amounts of destabilization may now not be enough to beat out the
weak inhibition, and not to mention the relatively weak
convergence ahead of the boundary leaves questionable forcing
available for ascent. RAP and HRRR model soundings demonstrate
decent lapse rates around 8.5 K/km, but above 900 mb are not
nearly as impressive. As for the shear environment, 0-6 km bulk
shear looks to be only be around 20 knots, perhaps it could reach
25-30 knots in the northwest. Overall, convection will struggle to
become well organized across the north this afternoon and
evening, unless clearing occurs more rapidly than currently
anticipated. Any thunderstorms that do initiate along this
boundary will be rather pulsey. Perhaps a 60 MPH wind gust and few
hail stones can be squeezed out of one. HRRR and ESRL HRRR do not
have much development, while NSSL-WRF and NMM place isolated
thunderstorms north of Hwy. 20 later this evening. As mentioned
earlier though, CAMs have not been our most helpful tool in
convection forecasting as of late, thus will maintain low
confidence in the forecast. The bigger concern if convection does
develop will be decent rain efficiency of the storms. There will
be quite a bit of moisture sitting in front of the boundary,
characterized by PWATs ~1.75 inches. A localized storm could have
the ability produce up to an inch and a half of rain, presenting
an isolated flash flood threat. Again, this is conditional on
there being enough forcing for convection initiation to actually
occur this afternoon and evening. However, with low confidence at
this time, will hold off any flood watch across the north and
allow the evening shift to provide updates if needed. Another
story that begins today is an extended period of warm temperatures
and increasing heat indices. For today, northern Iowa will see
some high temperature relief with the lingering cloud cover, thus
have bumped down today`s high temperatures a few degrees north of
Hwy. 30. However, cloud cover has either been thin or skies clear
for areas along Interstate 80 and southward, thus have actually
bumped up temperatures a few degrees in this area closer to 90
degrees or just above, leaving a north-south temperature gradient
focused just north of Interstate 80 as a result of differential
heating between the clear sky area and the cloud covered area.
Sunday and Monday:
Push of WAA at H85 continues through the end the weekend and the
start of the next work week. This will modestly increase H5 heights
and with a small amount ridging in the pattern, keeping mid-level
and upper-level flow rather weak across Iowa. H85 temps will remain
above 20 C during this time, keeping surface temperatures in the
lower to mid 90s. Dewpoint temperatures will remain in the upper 60s
to lower 70s on Sunday and Monday, putting heat indices in the mid
90s. With weak flow and no apparent forcing available, expecting dry
conditions for Sunday and Monday.
Extended:
Overall flow will remain rather week through the next 7 days, and
will transition between zonal flow and slightly amplified ridge over
the Plains and Upper Midwest. Through Thursday morning there will
not be any aggressive forcing, thus will keep the forecast mostly
dry. The main story will be the heat, with afternoon high
temperatures in the lower to mid 90s, and heat index values hanging
around the mid 90s. Thursday evening into Friday early morning GFS
depicts short-wave with some forcing that could prompt precipitation
activity throughout the CWA, however the ECMWF keeps the forcing
with this short-wave further north, with just northern portions of
the CWA being clipped by precipitation. The other wild card factor
for the middle-end of this week will be the track that remnants of
TS Barry take. Prior to the 12z runs this morning, the NAM kept it
further west and impacting Iowa, while GFS and ECMWF kept it further
east and only increasing cloud cover but causing no precipitation
for Iowa. Today`s 12z NAM appears to be favoring a slightly further
east solution now, which would limit precipitation. At this point,
with the weak mid and upper-level flow, there is still uncertainty
as to how the remnants of Barry interact with the mid-latitude
synoptic setup. It could increase cloud cover across Iowa, which may
actually bring relief to the high heat index values on Thursday.
With the high uncertainty of these details, have not greatly
deviated away from blended guidance. As TS Barry is sampled by
inland observations, hopefully guidance will be able to converge a
solution to pinpoint cloud and precipitation impacts in the extended
forecast.
&&
.AVIATION.../For the 06Z TAFS through 06Z Sunday night/
Issued at 1056 PM CDT Sat Jul 13 2019
Earlier convection has diminished over northern Iowa. Little in
terms of forcing other than weak warm air advection over the
northwest. Hires and synoptic models indicate lack of forcing the
remainder of tonight and remainder of period as lift/warm air
advection shifts north into MN/WI. Winds light/var or light south
becoming more southwest aft 12-15z Sunday. VFR conditions to
continue other than minor patch of stratus northeast aft 15z
Sunday. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Krull
AVIATION...REV
Area Forecast Discussion
National Weather Service Quad Cities IA IL
635 PM CDT Sat Jul 13 2019
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 258 PM CDT Sat Jul 13 2019
Morning storms approached and eventually encroached into the far
northern CWA on the Iowa side, but after making contact with the
Highway 20 latitude, they encountered stronger capping, and have
died. In the wake of this dissipation, scattered cloud cover and
associated MCV are found over Iowa, leaving the mesoscale features
to determine the threat for any new storms.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 258 PM CDT Sat Jul 13 2019
Outside of a few sprinkles associated with the MCV, there is little
precipitation taking place over Iowa. Eventually, convergence along
the collapse of the meso high/outflow may allow for new cell
formation, but given the capping still in place, that activity
should be isolated in nature. For now, the general model placement
of this isolated activity would be north of I-80, but I don`t have
much confidence in this. It could be anywhere the convergence
briefly sets up late today. The HRRR and RAP continue to show
intense convection this afternoon and this evening, and for that the
SPC Marginal risk remains in place. However, it should be noted that
these models are too hot, with surface temperatures in the mid 90s
this afternoon. That`s generally 5 to 7 degrees too high, and thus,
I feel that development is overdone. As the evening wears on
tonight, any storms should become less and less likely.
Sunday, I have left a thin band of slight chance pops northeast, in
case any activity can build southwest from the main axis of storms
over the upper Great Lakes. Otherwise, a hot and humid day is again
forecast. With highs in the lower 90s widespread, and isolated mid
90s in urban heat areas (Moline), the heat index will approach the
upper 90s in the afternoon. This is short of heat advisory levels,
but will be plenty warm to advertise a continued threat Sunday.
ERVIN
.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 258 PM CDT Sat Jul 13 2019
THe main forecast concerns are temperatures as well as chances of
precipitation. Models are in good overall agreement with the
usual differences in the timing and placement of features.
A quasi zonal flow will be in place across the CONUS through the
remainder of the week. The jet stream will sink southward by midweek
as Barry moves northward and transitions to an extratropical
cyclone and is absorbed into the 500 MB flow as a series of
shortwaves moves across the northern tier.
Currently the forecast is dry through Tuesday morning as the remnants
of Barry move into central Illinois. The better lift will remain
over central Illinois This will bring the risk of showers and
thunderstorms to the far eastern edges of our CWA mainly along a
Princeton Illinois to Macomb Illinois line. At the same time, a
series of shortwaves will pass to our north across Minnesota and
Wisconsin Tuesday night through Wednesday night bringing the risk
of showers and thunderstorms.
A stronger shortwave will dig into the area after 00 UTC Thursday
bringing the best chance of showers and thunderstorms through 00
UTC Friday. In the wake of this system, models predict strong
ridging building across the Plains and pushing the jet stream into
southern Canada. Some timing and placement issues between the GFS
and ECMWF at this time as the GFS is farther east with the ridge
axis building into eastern Nebraska and kansas while the ECMWF has
the ridge farther to the west in eastern Colorado and western
Nebraska and Kansas but it leaves the jet stream in place just to
our north across Minnesota and Wisconsin. Both models have a very
strong 596 dm high in place across the Plains so oI would lean
more toward the GFS solution with that strong of a ridge in place.
In general, temperatures through the week will be in the lower to
mid 90s with the warmest days potential being Thursday through
Saturday. This will combine with dewpoints in the upper 60s to
lower 70s to produce heat indices in the upper 90s to around 100.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 631 PM CDT Sat Jul 13 2019
VFR conds through this taf cycle with isolated storms possible on
Sunday. This chance is mainly during the late morning and afternoon
hours but low enough to keep mention out of TAF forecasts. Light
and variable wind tonight then south less then 10 knots on Sunday.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...Cousins
AVIATION...Haase
Area Forecast Discussion
National Weather Service Grand Junction CO
539 PM MDT Sat Jul 13 2019
.SHORT TERM...(Tonight through Sunday night)
Issued at 338 PM MDT Sat Jul 13 2019
A southerly tap of moisture wrapping around the backside of high
pressure centered over northeast New Mexico/southeast Colorado has
aided in the development of scattered showers and thunderstorms
this afternoon. Precipitable water values, currently estimated
around 0.75 to 0.90 inches, will continue to steadily climb
before topping out between 0.90 and 1.20 inches late this evening.
Frequent lightning, gusty winds of 40 to 50 MPH, small hail, and
brief heavy rain will all be possible with the stronger storms
before activity begins to subside between sunset and midnight.
However, high res models, namely the HRRR and NAMNest, project
isolated showers will persist through sunrise Sunday. Tomorrow
will see the high drift southwest, cutting off the tap of moisture
from the south. Even so, residual moisture will allow for another
round of scattered convection to develop by mid to late morning
with activity favoring the southern and central Colorado mountains
through sunset. Elsewhere, expect partly sunny skies with
slightly cooler, albeit near seasonal, temperatures. A quiet night
is on tap for tomorrow night as drier air continues to filter
into the region from the southwest.
.LONG TERM...(Monday through Saturday)
Issued at 338 PM MDT Sat Jul 13 2019
A trough of low pressure situated along the west coast will slowly
drift inland early next week, gradually squashing high pressure
situated over the Desert Southwest. This will lead to persistent
southwest flow aloft across eastern Utah and western Colorado and
result in a drying and warming trend. While residual moisture will
fuel isolated convection over the higher terrain each afternoon
through midweek, storm coverage will decrease as the days
progress and as available moisture sharply dissipates. Tuesday and
Wednesday will see the gradient tighten overhead with humidities
approaching critical levels across the western tier of the
forecast area. These breezy, drier conditions will have to be
monitored for potential fire weather highlights over the coming
shifts. Flow aloft becomes zonal on Thursday before the
subtropical high quickly amplifies on Friday. Discrepancies
persist with the latest model run in the location of the high
pressure center Friday night and into Saturday as well as the
intensity of higher heights. The GFS favors a sharper, more
amplified ridge axis centered over the Central Plains while the
Euro`s ridge is drastically weaker, centered further east. The GFS
solution would allow for another tap of subtropical moisture to
be incorporated into the Four Corners while the Euro`s current
projection would inhibit the plume from drifting north. Much of
the projected highs intensity and placement hinges on the track of
a strengthening Pacific trough so forecast confidence remains low
for the end of the extended period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 537 PM MDT Sat Jul 13 2019
Scattered showers and thunderstorms will continue to impact
eastern Utah and western Colorado through 06Z this evening. Heavy
rain, frequent lightning, small hail and gusty outflow winds to 50
kts will be possible. Expect cigs to briefly reach ILS breakpoints
and possibly drop into the MVFR thresholds near the stronger
storms. The convection will dissipated after 06Z with VFR
conditions returning through midday Sunday. Another round of
convection will then develop Sunday afternoon.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...MMS
LONG TERM...MMS
AVIATION...JDC
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1002 PM CDT Sat Jul 13 2019
.UPDATE...
TS Barry`s convection still behaving as it was 24 hours ago; that
of the bulk of the northern Gulf thunderstorm activity developing
and maintaining itself along the southern periphery of the near
1000 mb surface low over southwestern Louisiana. Other than some
thin bands of mainly showers with an embedded storm or two around
Barry`s western edge, the area will not receive much more rain
from what will become the remnants of Barry by this time tomorrow.
Moderate to likely rain chances will reside along the coast and
points offshore through Monday to account for these trailing outer
bands. Most of the model solutions are still focusing the bulk of
the highest 24-48 hour QPF within the trailing southwesterly low
to mid level trough left in Barry`s wake as its remnant low
crosses the Mississippi River out of Arkansas. Partially clear
early Sunday conditions with sunrise interior mid 70 F minTs...
around 80 F along coast. Sunday will be warmer out west where
more sun and less rain will peak temperatures at around 94
F...near 90 F further east under more overcast and periods of
daytime precipitation. 31
&&
.PREV DISCUSSION... /ISSUED 627 PM CDT Sat Jul 13 2019/
AVIATION...
Conditions remain mainly VFR through the TAF period, although the
development of scattered storms tomorrow afternoon will need to
be watched closely. Currently seeing some SHRA/TSRA associated
with the outer edges of TS Barry move through the area. This
activity should last through around 03Z tonight. Winds remain out
of the N/NW overnight, dropping to 5 to 10 kt before shifting more
to the west and increasing to 10-15 kts tomorrow afternoon. Some
higher wind gusts are likely along the Gulf. We should again see
scattered SHRA/TSRA develop tomorrow beginning at around 16-18Z as Barry
continues its slow track northward, generally impacting the metro
and coastal areas. Cady
&&
PREV DISCUSSION... /ISSUED 303 PM CDT Sat Jul 13 2019/
DISCUSSION...
Barry has made landfall along Louisiana coast. It was briefly a
hurricane...now back to a strong tropical storm. Barry will likely
produce flooding rains mainly along and east of its track with
storm surge flooding also an issue. SE Texas will remain west of
the track with some wrap around showers and thunderstorms the
main impact but nothing that that significant. In the wake of
Barry possible a more stationary band of showers and thunderstorms
could set up mainly over southern half of area which could bring
higher rain amounts Sunday into Monday but details of this band in
terms of placement and intensity are still uncertain. WPC has
placed this zone in a marginal to slight risk of flash flooding
Sunday and Monday. Details below.
SHORT TERM [Tonight Through Monday Night]...
Good model agreement with Barry tracking slowly NW then N across
Louisiana over next 24 hours. Most of the significant impacts from
wind...surge...flooding rains and tornadoes should be along and
east of the track...really no significant direct impacts from
Barry for SE TX. Behind Barry models indicate an inflow band
extending from off the SE TX coast feeding NEWD then NWD into
Barry from the south. This inflow band in some models shifts
inland into coastal counties by Sunday afternoon and night and
hangs around through Monday. This band supported by low level
convergence between NW flow from departing Barry and a return to
onshore flow from the Gulf. An upper levels a trough to the west
provides diffluence aloft...perhaps aiding lift. Precipitable
water forecasts in the synoptic models showing values AOA 2 inches
at the coast so does appear to be some deeper moisture to tap
into.
The synoptic models produce quite abit of rain with this Sunday to
Monday band...but more so offshore...with perhaps 1 to 2 inches
along the coast...3 to 5 inches offshore...but certainly possible
some of those higher amounts could shift into land areas. Because
of this potential flash flood threat...although still highly
uncertain...WPC has placed southern portions of the forecast area
in a marginal to slight risk for flash flooding for Sunday into
Monday. For now something to monitor although even if it were to
play out not expecting nearly the rainfall they are receiving east
of the track...likely more localized flooding impacts if it were
to materialize...and no guarantee of that. Of the convective
allowing models...HiRes NMM WRF pretty bullish on developing this
band...TTU WRF...ARW WRF and 18z HRRR out to 30 hours not so much.
Again just something to watch for now.
Reilly
LONG TERM [Tuesday Through Saturday]...
Tuesday may be a transition day with band of showers and storms
still evident in GFS...but pattern evolves from troughiness at
surface and aloft to more neutral to ridging by late in the week.
As a result Wednesday and beyond look hot and mainly dry...but
will chance of typical summertime afternoon thunderstorm
development with less and less coverage through the week as upper
high and capping take hold. Still pretty unsettled at least
Tuesday. As we get drier we get hotter with highs mid to late week
well into the mid 90s...some upper 90s possible NW zones.
Reilly
AVIATION [18Z TAF Issuance]...
Diffuse rain bands with light showers spreading into the eastern
areas at 18z and should continue to push south and southwest.
Ceilings should be VFR with brief MVFR conditions possible if a
shower hits one of the airports through early evening. Expect some
patchy lower ceilings possible tonight across the western areas.
SHRA/TSRA chances increasing for Sunday morning along the BYY-GLS
corridor and will carry VCSH for rainbands over most sites after
13z...LBX/GLS more pessimistic and may need to add prevailing
there. Could see SW flow at LBX/GLS as well in the morning has
convergence area develops.
45
MARINE...
Northwesterly winds backing to the southwest tonight. Gusty
northwest flow now with gusts 20-25 knots so have adjusted the
flags with SCA now in Galveston Bay and the far coastal waters
including the nearshore waters near High Island. Building seas
tonight to 5-7 feet with more persistent southwesterly flow 20-25
knots. Expect scattered bands of showers and thunderstorms today.
Could see a persistent band of stronger storms Sunday across the
coastal waters.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 76 92 75 94 77 / 20 30 20 30 10
Houston (IAH) 80 93 78 94 79 / 40 50 40 50 20
Galveston (GLS) 80 90 82 89 82 / 70 70 60 50 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory until 8 AM CDT Sunday for the following
zones: Coastal waters from High Island to Freeport TX out
20 NM...Waters from Freeport to Matagorda Ship Channel TX
from 20 to 60 NM...Waters from High Island to Freeport TX
from 20 to 60 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION until 10 PM CDT this evening
for the following zones: Galveston Bay.
&&
$$
Discussion...31
Area Forecast Discussion
National Weather Service Lincoln IL
815 PM CDT Sat Jul 13 2019
.UPDATE...
Issued at 805 PM CDT Sat Jul 13 2019
An MCV is moving east across far northern Illinois while a
east/west oriented convergence axis associated with this wave has
settled south across the far northern tier of counties in the
central Illinois forecast area (Knox, Stark, Marshall). A few
showers did try to develop along this axis shortly before sunset
but have since dissipated. The likelihood of any additional
showers forming will further diminish with sunset leaving dry
conditions across the area through the remainder of tonight.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 301 PM CDT Sat Jul 13 2019
1930z/230pm surface analysis shows a nearly stationary frontal
boundary extending from central Michigan westward into northern
Iowa. While very little convection is currently ongoing along the
front, a well-defined Mesoscale Convective Vortex (MCV) noted on
visible satellite imagery over northeast Iowa will trigger
scattered thunderstorms across northern Illinois late this
afternoon into this evening. The airmass further south into the
warm sector remains quite capped as evidenced by a max layer warm
temp of 19C at around 780mb. Therefore think any storms that
develop will largely stay north of the KILX CWA. HRRR has
consistently kept the storms north, while only the 12z HRW NSSL
tries to bring them further south toward I-74. Have therefore
generally gone with a dry forecast this evening...with just 20
PoPs along/north of an Altona to Minonk line. Overnight lows
will drop into the upper 60s and lower 70s.
Central Illinois will remain sandwiched between the stalled front
to the N/NE and the remnants of Hurricane Barry to the south on
Sunday. Several CAMs suggest isolated convection near the front
and on the far northern fringes of Barry by afternoon. As a
result, have added 20 PoPs along/northeast of Lacon to Danville
line and south of I-70. Elsewhere around the area, mostly sunny
and hot conditions will prevail with highs in the lower 90s.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 301 PM CDT Sat Jul 13 2019
Clouds will be on the increase as Barry slowly approaches from
the south on Monday. While some models try to aggressively spread
precip northward into the area, think prevailing ridge of high
pressure and corresponding synoptic subsidence well ahead of Barry
will keep the precip largely at bay. Have therefore kept PoPs
confined to locations along/south of I-70...while the remainder of
the area stays dry.
12z Jul 16 models continue to be in good agreement with the track
of Barry...with the remnant low reaching southeast Missouri by
12z Tue, then dissipating as it shifts into the Ohio River Valley
on Wednesday. This particular track will keep the heaviest
rainfall focused from Arkansas northeastward across the western
halves of Tennessee and Kentucky...with rainfall amounts steadily
decreasing further northwest. Have brought chance PoPs as far
northwest as I-55 on Tuesday: however, it appears the most
significant rainfall will occur along/south of I-70 where the
latest projections suggest storm total QPF of one half to one
inch.
Once the low exits, all models are showing a strong upper ridge
building over the region by the end of next week. As a result,
temperatures are expected to rise into the lower to middle 90s by
next Thursday/Friday with heat index values exceeding 100 degrees.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 624 PM CDT Sat Jul 13 2019
High pressure over the region will continue to provide VFR
conditions and light winds. Winds will be light and variable, if
not calm at times, through the rest of today into Sunday morning,
then should become southerly Sunday afternoon as the ridge axis
shifts east.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Deubelbeiss
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Northern Indiana
725 PM EDT Sat Jul 13 2019
.SYNOPSIS...
Issued at 320 PM EDT Sat Jul 13 2019
Hot and humid conditions can be expected to continue through the
upcoming week. Afternoon high temperatures Sunday through
Wednesday will range from the mid 80s to low 90s, and will warm to
the low to mid 90s late in the work week. Heat indices in the 90s
can be expected for much of the upcoming week, and may exceed 100
by Friday. Otherwise, an isolated shower or thunderstorm is
possible tonight, with another slight chance of showers and
thunderstorms Sunday afternoon and evening south of Route 30.
&&
.SHORT TERM...(This Evening through Sunday)
Issued at 320 PM EDT Sat Jul 13 2019
Convective chances through this evening, and then again on Sunday
will be the primary short term forecast concern.
Earlier day showers and thunderstorms across eastern Iowa have
diminished, and focus for late afternoon into tonight will be on
smaller scale short wave kicking out of eastern Iowa/northern
Illinois. Surface cool front from eastern Iowa into west central
Lower Michigan will continue to slowly sag southeast this evening as
Ontario/Quebec larger scale wave shifts east. Pooled moisture in the
vicinity of this front will likely be the focal point if any
isolated showers and storms are able to develop. Latest RAP near
term progs indicate narrow axis of 1500 J/kg MLCAPE corresponding
to this pooled moisture axis. Best shear is post frontal in nature
across the Great Lakes, so not expecting much in the way of storm
organization with any late afternoon/evening isolated activity.
Previous PoPs generally were preserved this cycle.
With eastward departure of south central Canada upper trough and
subtle mid/upper level height rises across the mid/upper MS Valley,
cold front will stall across the area on Sunday. Difficult to
isolate a distinct forcing mechanism with this stalled frontal
boundary on Sunday, but would suspect isolated-widely scattered
shower/storm coverage coincident with peak heating across
approximately southwest half of the forecast area Sunday
afternoon/early evening based on expected frontal placement.
Shear profiles become even less impressive on Sunday due to
aforementioned height rises, so not expecting much organization
although a few stronger cells could produce brief gusty winds and
brief heavy downpours.
Lingering effects of pooled moisture axis should allow for slightly
higher heat indices on Sunday, with some mid 90s heat indices
possible across far south/southwest.
&&
.LONG TERM...(Sunday Night through Saturday)
Issued at 320 PM EDT Sat Jul 13 2019
The main concern for the long term period will be building
heat/humidity, especially by the Thursday/Friday period. Confidence
is beginning to increase in the potential of 100+ heat indices by
the end of the work week. Convective chances are of somewhat lower
confidence and will be somewhat dependent on the evolution of the
remnants of tropical system Barry.
On Monday, a ridge riding short wave is expected to eject out of
the Northern Plains with downstream low level jet/theta-e
advection likely allow renewed convection to develop upstream.
Confidence in whether this will affect locations far enough south
as local area is still on the low side so will just maintain
slight chance PoPs.
Remnants of tropical system Barry will lift northeastward Tuesday-
Wednesday, although exact details regarding interaction with the
northern stream will need to be resolved to determine just how far
north mid/upper forcing will make it. It does appear at least
possible that departure of Monday short wave could provide enough
weakness in northern stream for this upper trough to make it as
far north as Ohio Valley region. In any event, it does appear
confidence is higher in at least diurnally driven enhanced chances
of showers and storms Tue-Thu period as weaker smaller scale
perturbations lift northward from the Lower MS Valley.
Medium range models differ significantly on another eastern Pacific
wave possibly impacting region for Friday, with operational GFS
remaining a stronger outlier in comparison to EC/GEFS means.
Building upper level ridge should occur some time in the Thu-Sat
period, with timing in this evolution depending on strength of
this next eastern Pacific wave. Concern continues to increase with
building heat again for the Thu-Sat period with heat indices 100+
looking more likely, especially by Fri-Sat.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 718 PM EDT Sat Jul 13 2019
Weak cold front was slowly sagging south across northern Indiana
and was between terminals. Satellite shows a well defined short
wave across southern WI quickly moving southeast while lake breeze
boundary off of Lake Michigan was pushing westward across NE IL
and SE WI. Latest hires guidance develops some convection near
intersection of surface boundaries and short wave. Already seeing
a couple cells develop over northern IL. Will loosely follow CAMs
but only to VCSH extent at this time as models have been overly
aggressive with convective development up to this point. May need
to add some thunder if further development does take place this
evening but uncertainty too high at this time.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Marsili
SHORT TERM...Marsili
LONG TERM...Marsili
AVIATION...Lashley
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