Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/14/18
Area Forecast Discussion
National Weather Service Bismarck ND
1034 PM CDT Fri Jul 13 2018
.UPDATE...
Issued at 1025 PM CDT Fri Jul 13 2018
No changes this update cycle.
For the thunderstorm chances Saturday afternoon, mesoscale hi
resolution models forecast development from north of Minot to
Bowman after 4 pm CDT, and push it east.
UPDATE Issued at 705 PM CDT Fri Jul 13 2018
The isolated thunderstorm that formed on the Montana border south
of beach has now dissipated in southeast Golden Valley County.
With heating waning will expect no other development and will also
forecast cu field to start dissipating next two hours.
&&
.SHORT TERM...(This afternoon through Saturday)
Issued at 219 PM CDT Fri Jul 13 2018
Highlight in the short term period continues to be the Marginal
Risk for severe thunderstorms for all but the northwest and James
River Valley.
For the near term, now through sunset, latest visible imagery
shows a cumulus field growing across western and central ND.
Soundings still suggest that further growth toward convective
showers should be limited due to a shallow and narrow subsidence
inversion within the 10kft to 14kft layer. Will continue to
monitor, but at this time despite adequate CAPE and associated
strong low level lapse rates, the bulk of the cumulus should
flatten out as parcels push into the inversion aloft as mentioned
above. Per HRRR model, a couple of showers are possible, but due
to sparse development, trying to pinpoint where any shower will
initiate along with the areal coverage is too difficult at this
writing. Will leave the forecast dry at this time. The cumulus
will dissipate by sunset as surface heating ends.
Dry tonight with a clear sky and lows in the mid 60s. Expect a
sunny start on Saturday, followed by the development of showers
and thunderstorms along and ahead a potent cold front beginning in
the mid afternoon (north central), then developing farther south
by evening. This cold front is linked to a Canadian upper level
shortwave trough which remains just north of the border, but
enough large scale ascent droops into north central ND for what
appears will be the initial location for thunderstorm development
by mid to late afternoon. Farther south, strong surface heating
along and ahead of the strong cold front with temperatures rising
into the upper 80s to mid 90s will allow for weakening/erosion of
the CIN layer per BUFKIT soundings.
There continues to be a narrow but consistent and pronounced
corridor of moderate instability (Mixed Layer CAPE in the
1500-2500 J/Kg range) and deep layer shear (0-6km Bulk Shear)
ranging between 25kt and 40kt, mostly focused over north central
North Dakota Saturday afternoon, which would include places like
Sherwood, Minot, and Bottineau. As mentioned in the midnight
discussion, deep layer shear vectors are initially perpendicular
to the surface cold front indicating discrete storm mode. As the
front continues to propagate south and east in the late
afternoon/evening, the shear vectors become more parallel to the
boundary with perhaps more of a linear/multicellular storm mode.
ML CAPE weakens to less than 1000 J/Kg from 03z-06z, and we should
see a diminish in the overall severe weather threat during this
timeframe. Isolated large hail and strong wind gusts remain the
main threats. Due to the isolated nature/marginal risk, have opted
not to mention severe wording in the grids, but will continue to
highlight it in the Hazardous Weather outlook.
.LONG TERM...(Saturday night through Thursday)
Issued at 219 PM CDT Fri Jul 13 2018
Strong cold front will continues to propagate through central
North Dakota with showers and thunderstorms eventually ending by
12z Sunday as the back edge of the precipitation shifts south of
the border. Gusty northwest winds right behind the frontal passage
can be expected at least for a couple hours as boundary layer
winds are advertised between 25kt and 30kt.
Dry upper level northwest flow void of any shortwaves will take
control through Monday, thus expecting dry weather. Much cooler
and less humid Sunday with highs in the 70s, then upper 70s to
lower 80s Monday.
Broad ridging/warmer air returns Tuesday and Wednesday ahead of
our next shortwave slated for Wednesday night, which skirts mainly
the northern counties. For Thursday into Saturday, should see a
return toward west and southwest flow aloft for a better chance of
showers and thunderstorms. Highs will be in the 80s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1025 PM CDT Fri Jul 13 2018
A cold front will be entering northwest North Dakota Saturday
afternoon with thunderstorms developing along and ahead of it. As
of this update issuance it looks like the front will be east of
KISN before storms fire, after 142100Z. The most likely TAF sites
to get a TSRA before 150000Z will be KMOT to KDIK, followed by
KBIS after 150000Z. For the 00Z TAFs no TSRA was added. For the
06Z TAFs it will likely be added at KMOT, KDIK and KBIS, and
possibly to KJMS very late in the TAF valid period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...KS
LONG TERM...KS
AVIATION...JPM
Area Forecast Discussion
National Weather Service Denver/Boulder CO
826 PM MDT Fri Jul 13 2018
.UPDATE...
Issued at 816 PM MDT Fri Jul 13 2018
Airmass is stabilizing in the mountains with only one storm left
down in southeast Park county. This should be done by 10 pm with
brief rain, gusty winds and lightning. Much of northern Colorado
under the dominating ridge to our west so mostly clear skies for
the rest of tonight. The exception would be out over far eastern
Colorado where there will be some return low level moisture under
a east to southeast low level flow. High resolution models showing
this low level moisture generally from a Limon to Sterling line
and points east. Will increase cloud cover in those and areas and
add patchy fog to the forecast. No other changes need for tonight.
Any thunderstorms on Saturday look to be confined to the
mountains and Palmer Divide.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 310 PM MDT Fri Jul 13 2018
Storms have formed over the Continental Divide and will continue
to do so through the early evening. These storms will struggle to
move off the mountains and onto the urban corridor due to slow
storm motion and low shear. The HRRR is continuing to show the
strongest storms developing along I-80 in SE Wyoming and pushing
south to Larimer and Weld counties. These storms will be capable
of producing wind gusts up to 40 mph especially near the CO/WY
border.
Showers and storms will dissipate by late evening with the loss of
daytime heating. Low temperatures will be very close to normal
tonight with light winds.
Conditions are setting up for a hot and mainly dry day tomorrow.
An upper level ridge will position itself directly over Colorado
with 700mb temperatures warming to around 17 degrees near Denver.
With mostly sunny skies expected due to the lack of ascent, highs
will reach the low to mid 90s across the urban corridor and
eastern plains. Have added POPs along and slightly south of the
Palmer Divide due to better convergence in that area. The HREF
shows storms developing there with some of the stronger storms
producing gusty outflow winds. Otherwise, a few storms could
develop along the Continental Divide but these will be brief and
isolated in nature.
.LONG TERM...(Saturday night through Friday)
Issued at 310 PM MDT Fri Jul 13 2018
...Cooler and more storms Sunday through Tuesday before warm and
dry conditions return for later in the week...
Isolated storms will be diminishing over the high terrain and
Palmer Divide Saturday evening. Can`t rule out a few showers over
the high terrain overnight as an approaching upper trough over
the northern Rockies creates weak upward QG. A deepening surface
low over the eastern plains overnight will keep low temperatures
warm and some gusty winds in the foothills.
A cold front will push down over the forecast area Sunday morning
for max temperatures 5 to 10 degrees cooler than Saturdays
readings. Upslope flow and moisture advecting in from the west
will increase PW by 0.3-0.5 inches across the area. Look for
scattered to numerous showers and thunderstorms across the area
with lightning, brief heavy rain, gusty winds and small hail being
the main threats.
Upslope flow will remain in place Monday with shear increasing
across the area. This will continue the increase in storm
coverage and bring a chance of strong to severe strength storms.
Temperatures will be similar to even a couple degrees cooler east
of the Divide.
Models coming into better agreement for mid and later next week,
but still some differences. GFS is deeper with a shortwave trough
pushing across the area Tuesday, but GEM and EC still showing
hints of a weak disturbance. Some hints from all models of a lee
trough building in from the south, but easterly flow over the
from the Great Plains high pressure will keep high amounts of
moisture available for the Colorado eastern plains yet again. Will
have higher PoPs for this area.
The Southwestern US upper high will then strengthen and move east
Wednesday to be over southwestern Colorado by Friday. This will
bring warmer and drier conditions for the second half of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 816 PM MDT Fri Jul 13 2018
VFR with mainly clear skies tonight. Easterly surface winds will
shift southeast between 03z-04z before turning more southerly
later tonight. Dry day again expected on Saturday.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Entrekin
SHORT TERM...Danielson
LONG TERM...Kriederman
AVIATION...Entrekin
Area Forecast Discussion
National Weather Service Lincoln IL
910 PM CDT Fri Jul 13 2018
.UPDATE...
Issued at 908 PM CDT Fri Jul 13 2018
The southern end of a line of storms is pushing through our NW
counties this evening. It looks poised to progress to the E-NE at
20 mph the rest of the evening, with locally heavy rainfall and
wind gusts to 40 mph possible. MUCAPEs of 2500-3000 J/kg are
available, with weak Bulk Shear of 15kt. Increasing CINH should
help to diminish the strength of the storms as the evening
progresses. Have increased the PoPs to Likely/Categorical ahead of
the line, with chance PoPs south to Peoria/Morton and east to El
Paso later this evening.
The cold front associated with this system will make slow but
steady progress toward NW Illinois through tomorrow, with storm
chances remaining confined to the NW half of our forecast area.
Increased cloud cover and persistent southerly winds ahead of the
front will keep moisture levels high, with warm/muggy overnight
conditions. Muggy air will set up heat indices tomorrow reaching
near 105 in portions of central IL. A heat advisory may be needed.
Forecast updates were mainly related to weather/PoPs/Sky. The
remainder of the forecast looked on track. Updated forecast info
is already available.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 249 PM CDT Fri Jul 13 2018
A weak cold front to the northwest is slowly edging towards the
Mississippi River Valley this afternoon. Some ongoing convection
along the boundary and its associated outflow reinforcing the
surface reflection. Some convection has broken out ahead of the
front as well, concurrent with an upper wave moving into the
region this afternoon. This convection is moving along with the
southwesterly flow ahead of the front, and may only clip the far
NW with showers/TS in the early evening. The chances for showers
and thunderstorms through the overnight will start to spread as
the boundary slowly drifts, hung up in parallel flow. Losing
sunlight, the diurnal component added into the showers and
thunderstorms ahead of the boundary may well suppress some of the
development in the overnight, keeping much of the activity to the
NW with the front. Only catch would be if any of the storms this
afternoon develop a strong cold pool/outflow that might provide a
mesoscale boundary. That same concern perpetuates the threat for
precip through Saturday. The HRRR initiates storms early in the
day, the NAMNest remains largely dry through Saturday, re-firing
in the afternoon hours along some discontinuity in a variable and
light wind field at the surface. Between the small upper waves,
the front, and the outflows...the forecast for tomorrow afternoon
is problematic. The best chances will be for the afternoon
stretched across the midsection of the state, but will likely see
some gaps in coverage overall. Temps tomorrow will vary
considerably with the cloud coverage and storm development. Areas
to the west will see the higher temps and dewpoints, with moisture
advecting into the region from the precip. Heat indices will
climb to near advisory criteria, but stay just shy of 105F in most
areas.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 249 PM CDT Fri Jul 13 2018
Beyond Sat/Sat night, the boundary stalls over the region, now
predominantly just to the NW. Models are all pulling weak waves
across the region aloft, keeping pops in the forecast for the
remainder of the weekend and through Monday. The frontal passage
Monday afternoon/overnight will be the best chances for a more
widespread rainfall, with the PW quite dependent on how loaded
with moisture the soundings will get through the weekends
convective activity. Once the front moves through the region, the
temps cool into the mid 80s into the middle of the week. Thursday,
the next system deepens enough aloft to pull some cooler into the
mid levels from the northeast, potentially setting up some decent
lapse rates for showers and thunderstorms for Thursday
night/Friday...and offer a different temp profile for Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 648 PM CDT Fri Jul 13 2018
A cold front will continue a slow advancement toward NW Illinois
tonight. The front will eventually stall across the northern
portion of central IL. Despite limited convergence along that
front, scattered showers and storms will gradually advance to the
south from late tonight through tomorrow afternoon. The start of
storms tonight looks to reach near PIA after midnight tonight,
while the other TAF sites remain dry through sunrise. Storm
chances will eventually expand to all but CMI during the day
tomorrow. Have only included VCTS to acknowledge storm potential
periods tomorrow. VFR conditions will prevail for a majority of
the next 24 hours, with brief periods of MVFR or even IFR is any
storm moves over a terminal site.
Wind direction will be S-SE tonight, then variable as the front
arrives and stalls out. In general, southerly winds look to be the
primary direction, with wind speeds mainly below 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Jacksonville FL
848 PM EDT Fri Jul 13 2018
.UPDATE...Scattered showers and isolated t-storms continue
with converging boundaries early this evening...likely to
continue a few more hours before diminishing as suggested by
HRRR and hi-res NAM. Current low temperature forecast looks
fine.
&&
.AVIATION...VFR conditions expected next 24 hours. Included
VCTS tomorrow at TAF sites tomorrow afternoon.
&&
.MARINE...No significant changes planned in next CWF issuance.
A back door front will wash out across the waters this weekend
producing scattered showers and storms. Light and variable winds
becoming onshore in the afternoon. A western Atlantic ridge will
build south of the waters next week producing an increase in south
southwest winds...however winds and seas expected to remain just
under cautionary levels.
Rip Currents: A lingering long period swell has prompted a high risk
along the Ne Fl beaches through early this evening. Otherwise a
moderate risk expected through Saturday.
Coastal Flooding: Perigee spring tides (closest new moon of the
calendar year) will continue through the weekend, resulting in
elevated high tide cycles. Forecast water levels suggest tides will
remain near or just under action stage and no coastal flood
statements expected at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 76 91 73 90 / 30 70 40 50
SSI 79 88 77 88 / 30 50 40 50
JAX 75 92 74 91 / 10 50 40 50
SGJ 76 90 74 88 / 10 40 40 50
GNV 74 92 74 91 / 30 50 40 60
OCF 74 93 73 90 / 20 40 20 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Wolf/Hess/Corless
Area Forecast Discussion
National Weather Service North Platte NE
619 PM CDT Fri Jul 13 2018
.SHORT TERM...(This evening through Saturday)
Issued at 220 PM CDT Fri Jul 13 2018
Weak 1018mb high pressure will remain overhead tonight and the
models suggest patchy fog by morning. The limiter on the fog
might subsidence with backed winds aloft; none of the models show
widespread fog.
The RAP model shows a slug of dry air at the 750-700mb level and
this should support good radiational cooling. The forecast
follows the model consensus which indicates a few hours of spotty
low visibility developing throughout wrn and ncntl Nebraska.
There is still a few hours of isolated shower chances this
evening; mostly forced by the heating cycle and affecting areas
east of highway 83. No rain is expected Saturday.
The temperature forecast is a blend of guidance plus bias
correction for lows tonight mostly in the 60s and highs in the
80s to near 90 Saturday.
.LONG TERM...(Saturday night through Friday)
Issued at 220 PM CDT Fri Jul 13 2018
Increased chances for showers and thunderstorms Sunday-Monday.
Presently the risk for hazardous weather/severe storms hail or
damaging winds appears low Sunday and Sunday night given the
environment. Current thinking is isolated to scattered coverage
with the greatest threat towards the eastern Panhandle and
southwest for moderate rain, locally heavy possible, and
thunderstorms. The large scale pattern early Saturday night will
be characterized by an upper-level trough across the Northern
Rockies and northern High Plains with an upper-level closed low in
northern Saskatchewan. Over the next 24 hrs the upper-level
closed low will move southeastward across northern Manitoba with
the associated trough moving across the Northern Plains. Meanwhile,
a cold front extending from a surface low in northern Manitoba
across central ND into northern WY Saturday night will move to the
far northeast NEB Panhandle Sunday morning. The front is expected
to advance across the Sandhills Sunday as an embedded disturbance
also moves across SD and northern NEB. Environment is characterized
by weak mid-level lapse rates (5-6.5 C/km); limited to marginal
instability with tall, skinny, CAPEs evident from soundings; and
ample moisture. Moisture is decent with precipitable water values
1.25-1.6, about 150% of normal and greater, deep moisture in the
column, and dew points largely in the mid to upper 60s. Thus up
to moderate rainfall is expected, perhaps locally heavy at times.
Precipitation chances continue into Monday. However, there is a
little more uncertain given overall lift and forcing, and the
influence of surface high pressure moving in. Start to see a
cooling trend begin across northern NEB Sunday that spreads
across the remainder of the local forecast area Monday. Highs
about 4-8 degrees below seasonable normals Monday, upper 70s to
lower 80s.
Modest northwest flow in place over western NEB in the large
scale pattern Monday night with a disturbance moving from the
Northern/Central Rockies early Tuesday across western NEB
Wednesday. This will promote largely unsettled conditions through
Wednesday. However, guidance does show differences in the Tuesday-
Wednesday time period with respect to amplitude and phase with
this feature and its overall evolution. Nonetheless anticipate
chances during the Tuesday-Wednesday time frame that peak Tuesday
evening-early Wednesday at this time based on timing of the large
scale forcing and environment, especially across southwest NEB
and central Sandhills-north central NEB. Highs this time frame
then continue to be below to near seasonable normals, coolest
temperatures on Tuesday.
500 hPa height rises spread across NEB Thursday as a ridge builds
and shifts from the southwest CONUS to the Four Corners Wednesday-
Thursday. This ridge extends across the Central High Plains into
the Northern Plains by Thursday. This will promote warming
temperatures and a general drying trend Thursday-Friday. Highs
are forecast to generally approach then meet the lower 90s in the
eastern Panhandle and portions of western NEB Thursday and Friday,
respectively.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 619 PM CDT Fri Jul 13 2018
VFR is expected throughout western and north central Nebraska
until 09z tonight. Thereafter, the models show MVFR/IFR/local
LIFR in patchy fog forming and affecting mostly southwest and
central Nebraska. At KLBF, a tempo for 4sm br included from 11z
until 13z. Model indicate differing locations for fog development,
so confidence on coverage and visibility from fog is below
average.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...ET
AVIATION...Roberg
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
734 PM CDT Fri Jul 13 2018
.MESOSCALE DISCUSSION...
734 PM CDT
A weakening bow echo is pushing into Northwest IL and Southern
WI. RAP analysis shows an axis of 3500+ J/kg of sfc CAPE with the
bow and 900 J/kg of downdraft CAPE. Shear is negligible;
therefore, much more concerned about damaging winds and downbursts
than hail. MRMS estimates are showing rainfall rates of 1+" per
hour, but storms are moving at 40+ MPH so I`m not concerned about
flash flooding yet. If storms start to significantly train,
localized flooding could occur.
Additional storms are forming around Davenport, IA, and those
should reach the western forecast area in a couple of hours. Main
threats will be heavy rain, frequent lightning, and strong winds
through the evening.
JEE
&&
.SHORT TERM...
230 PM CDT
Through tonight...
Robust thunderstorm development has begun in the warm sector ahead
of a more organized upper level shortwave in western Iowa.
Additional forcing along the front extends northeastward into SE
Minnesota and western Wisconsin, with some diurnal heating storms
in SW Iowa out ahead of the main line. With a moist boundary
layer and decent sunshine, the environment ahead of this upper
wave and front will enable further destabilization and promote
renewed/continued thunderstorm development farther east toward the
Mississippi River this afternoon. Wind shear is not super strong,
but a bit better speed max will spread into SW Wisconsin this
evening.
Meso models are in good agreement in bringing this activity into
the I-39 corridor and Rockford area in the mid evening time frame.
With the boundary layer not likely completely decoupled at this
point and with arrival of a bit stronger speed shear, a few
stronger storms with a concern for gusty winds does exist. Those
with outdoor events this evening should keep an eye to the sky and
radar as these storms approach this evening, as lightning itself
is decent likelihood regardless of the severe concerns. Heavy rain
is a concern, as these storms are not moving all that fast,
although storm training chances are initially somewhat low.
Questions will then center on the eastern extent of this activity
as it moves into a slightly less favorable environment across
northeast Illinois. The concern though is potential MCS
development that may allow storms to move a bit farther
eastward/southeastward, the main storm motion is more
easterly/slightly northeasterly. Confidence is much lower that
these storms will maintain themselves to the Chicago lakefront,
but some showers will likely get out ahead of the main storm area
late this evening, more so after the 10-11 pm time frame or later
before weakening.
Overnight redevelopment is possible as instability aloft will not
decrease over the area overnight. Therefore with the upper forcing
sliding through and a frontal boundary in place, additional storm
development could occur, but confidence on coverage is low.
KMD
&&
.LONG TERM...
300 PM CDT
Saturday through Friday...
A humid weekend, much like those of June, will unfold for this
second full one of July. The moist atmosphere will bring
thunderstorm chances, more likely on Saturday than Sunday in terms
of at least coverage at this point.
Some of Saturday`s thunderstorm potential, coverage, and timing
will depend on how storms play out tonight. A generally moist and
unstable air mass should in place, with an outflow-modulated
surface trough draped across the area. This will probably be
somewhat broad but still a source of general low-level confluence,
along with any residual outflows. While there could certainly be
some morning storms, an uptick in coverage is likely during the
peak heating of the afternoon along the boundary, where mixed
layer CAPEs look to peak in excess of 2000 J/kg. Convection-
allowing guidance shows quite a spread in convective footprints,
but generally show scattered to numerous storms developing in
this broad trough corridor and evolving east-southeast around the
periphery of the upper level ridge. Confidence on coverage is not
the greatest, but felt that "scattered thunderstorms" was the best
verbiage to use in the forecast for Saturday and for mainly I-80
south Saturday evening.
Much like the storms of this summer, the risk of localized heavy
rainfall with PWATs near two inches and wet downbursts with 35+
mph gusts should be the primary concerns, as deep layer shear is
more marginal though not non-existent (around 30 kt). Isolated
multi-cell merging could bring a locally higher wind threat.
Dew points south of and up to the boundary should be into the mid
70s given current upstream conditions. Temperatures are a little
more uncertain especially north with some cloud cover, but in the
southern CWA, 90 should be more easily attainable Saturday
afternoon. Together this brings forecast heat index readings up
to 100 to 105 south of I-80. A lake breeze is anticipated, which
will likely keep areas near the lake only around 80.
The humid conditions continue into Sunday, though less of a
focus is expected for convection. Certainly the chance for
scattered storms, mainly south and west. Highs look to be in the
upper 80s to lower 90s depending on cloud cover, with again some
lakeside cooling.
The cold front to end this air mass is expected to drop through
the region on Monday, though some spread on timing. This will
bring thunderstorm chances as well. Prior to the frontal passage,
warm and very humid conditions are expected. Could again see highs
reach into the lower 90s.
Temperatures will drop back to seasonal readings for mid-July
during midweek.
MTF
&&
.AVIATION...
For the 00Z TAFs...
A line of thunderstorms moving into northwest IL will impact RFD
early this evening. Some storms have produced downbursts with
strong winds, and the strongest storms may produce strong winds
and hail. Heavy rain is also expected with the storms.
Additional showers and storms will shift southeast across the
region this evening. The storms should be weakening as they
approach the eastern terminals, but since storms are stronger than
expected now, I put a short tempo of -TSRA in the DPA and ORD
TAFs. I think the line will dissipate to showers by the time it
reaches MDW, and should dissipate before reaching GYY.
Confidence is still low in how storms will develop Saturday. Due
to the lack of confidence, I did not adjust TSRA timing in the
TAFs. Periods of thunderstorms are expected Saturday afternoon,
but exact timing and location will depend on what happens tonight
and where the boundary stalls.
The storms will also impact how far inland the lake breeze will
get. As such, I did not adjust the lake breeze timing.
JEE
&&
.MARINE...
310 PM CDT
A weak surface trough will creep its way southward down the lake
tonight. Thunderstorms and some outflows will likely be shifting
across northern to central parts of the lake this evening, and
into the south late this evening into overnight. More scattered
storms are likely across the south on Saturday, but the trough
will gradually weaken, so winds should be more light and variable
on Saturday apart from any storms. A cold front will shift
southward across the lake on Monday, turning winds northerly with
15 to 25 kt gusts possible Monday night into early Tuesday.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Pueblo CO
324 PM MDT Fri Jul 13 2018
.SHORT TERM...(This evening through Saturday)
Issued at 247 PM MDT Fri Jul 13 2018
Currently...water vapor satellite imagery continues to show dry air
moving south across the region as high pressure aloft spins over
Utah. Radar and satellite imagery indicate convection has remained
confined to the San Juan Range, and areas to near Raton New Mexico.
Temperatures have warmed nicely with highs in the upper 80s to mid
90s across the region.
Tonight...high pressure will continue to sit across Utah. Models in
good agreement with showers and thunderstorms generally remaining
south of the La Garita Range, southeast to the southern Sangre de
Cristo Mountains. This activity will progress south and west
through the evening hours, clearing the area around midnight. As
for the Plains, there may be an isolated thunderstorms late this
afternoon and evening, but coverage looks to be minimal at this
time. The primary threats from thunderstorms will be lightning,
gusty outflow winds and locally heavy rainfall. It should be noted
that earlier runs of the HRRR wanted to bring an area of
thunderstorms south off the Palmer Divide into Pueblo County this
evening, but the latest runs have very little if any thunderstorm
activity covering this area, especially with the dry air in place.
Overnight lows will fall into the mid 50s to lower 60s for the
Eastern Plains.
Saturday...the upper high will shift back eastward into western
Colorado through the afternoon. Residual moisture and modest
instability will lead to scattered shower and thunderstorm
development by late morning across the mountains. Lack of steering
winds aloft will lead to slow storm movements. If one of these slow
moving thunderstorms moves over a burn scar, flash flooding will be
possible. In addition, gusty outflow winds and lightning will be
threats as well. More isolated shower and thunderstorm activity is
expected over the Plains. Temperatures will once again be warm with
highs in the upper 80s to mid 90s across the Plains. Mozley
.LONG TERM...(Saturday night through Friday)
Issued at 247 PM MDT Fri Jul 13 2018
...Cooler Sunday/Monday with increased thunderstorm chances...
Upper level high pressure flattens slightly on Sunday, as vigorous
trough moves through srn Canada/nrn U.S. With mid level flow
becoming more wly Sun, moist plume drifts back across CO with an
uptick in convection expected over the nrn half of the region,
aided by approaching cold front and weak upper level lift from nrn
trough. Front then sinks south through the plains Sun night,
keeping a threat of storms going for areas along and north
Arkansas River into Mon morning. By Mon afternoon, frontal
boundary will sill be lurking somewhere over the eastern plains,
with NAM/ECMWF suggesting better storm chances slightly farther
south than GFS, which keeps the front north of the Arkansas River.
In either event, moisture remains in place with weak upper level
lift continuing, suggesting enhanced pops for many areas, along
with an increased threat of flash flooding/heavy rainfall with
slow moving storms.
Western U.S. upper ridge then begins to amplify from Tue into the
end of the week, with high pressure centered over srn CO by Fri.
Should see a fairly pronounced drying/warming trend as high builds
and low level moisture is shunted well south and west of the area,
though mid levels may remain moist enough for isolated weak storms
over the mountains each afternoon/evening. Max temps will begin a
slow climb from Tue onward, with readings near 100f returning to
the plains by Fri.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 247 PM MDT Fri Jul 13 2018
VFR conditions through the next 24 hours. Thunderstorms will likely
be possible at KALS through this evening. Reduced CIGS and VIS are
possible with any passing storms. There continues to be less
certainty over KCOS and KPUB, but isolated thunderstorms will.
remain possible through this evening. Another round of isolated
thunderstorms will be possible Saturday afternoon and evening.
Mozley
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MOZLEY
LONG TERM...PETERSEN
AVIATION...MOZLEY
Area Forecast Discussion
National Weather Service Tulsa OK
911 PM CDT Fri Jul 13 2018
.DISCUSSION...
The spotty late afternoon convection has gone away leaving
the forecast of the kansas complex as the problem. HRRR has
trended towards not much at all making it into northeast
Oklahoma and is similar to the rap. 1000-500mb thickness ridge
and the lack of any upper level flow along the ks/ok border
make the chances slim but can`t totally discount the nam/gfs/mav
and pcp is already to Wichita.
So will leave 20% in for northeast oklahoma after midnight.
No other changes with low pops left in tomorrow morning
in northern areas.
&&
.PREV DISCUSSION... /Issued 535 PM CDT Fri Jul 13 2018/
..UPDATE...
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Biggest aviation concern is the potential for thunderstorms to
affect mainly the NE OK terminals late tonight and into tomorrow
morning. Thunderstorms ongoing in parts of Kansas are expected to
make a run toward NE OK, although they are likely to be
diminishing in intensity. Will carry PROB30`s at BVO/TUL/RVS, with
potential for impacts at other terminals nonzero but below
mentionable levels. Overall, VFR conditions should prevail at all
terminals, except when any thunderstorms are present.
PREV DISCUSSION... /Issued 326 PM CDT Fri Jul 13 2018/
DISCUSSION...
We have failed to reach heat advisory criteria across the region
today. Temps have not climbed as high today compared to previous
days. Will make the final call on whether or not to pull the heat
advisory soon.
The latest hi res CAM data suggests storms that have developed
over KS along a weak upper trough may actually make a run at us
tonight. The HRRR has been trending more aggressive with a
southeastward push into our area by Saturday morning. PoPs were
inserted late tonight across NE OK, continuing into Saturday. More
storm development is possible across NE OK on Saturday afternoon
near aforementioned weak upper trough. Given the uncertainties
regarding convective potential and its possible impacts on
temperatures on Saturday, will hold off on any headlines at this
time. The current forecast does suggest borderline conditions, so
will let the next shift reevaluate.
Models maintain this weakness in the upper height field across the
north thru the weekend, and thus some PoPs were maintained during
this time. The first front will affect the region early next week
with continued convective potential, mainly across the north. A
stronger front toward the end of next week will likely shove the
humidity out of here and bring relatively cooler temps to close
out the week. The ridge will eventually rebuild over the Plains
over the weekend, so the heat will return.
Lacy
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...13
LONG TERM....13