Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/26/19

Area Forecast Discussion

National Weather Service La Crosse WI

 1103 PM CDT Thu Jul 25 2019

.SHORT TERM...(This evening through Friday)
Issued at 235 PM CDT Thu Jul 25 2019

Shortwave trough heading toward the area continues to produce rain
shower activity as it heads eastward. Have increased rain chances
west of the Mississippi river for this afternoon and early
evening and will continue to trend based on radar. Enough lift
generated to produce 10kft ceilings and light rain or sprinkles.
Currently there are no lightning strikes nor appreciable MUCAPE
over the area. Just a smidge of instability to get enough vertical
motion for SHRA production. Would expect this area to diminish
before reaching WI - but it has overachieved so far today.

Thunderstorms further NW in the SPC Slight risk over MN/ND will
try to work southeast toward the area overnight. It will likely
fail to arrive but the low-levels have a nice moisture tongue
headed into the western forecast area coincident with theta-e
convergence per RAP guidance. This isentropically rising low-level
jet could initiate higher-based TSRA/SHRA in the sunrise hours,
I-90 and north. Thus, rain chances have been refined for Friday
morning. Severe threat looks minimal with 250-500 J/Kg of MUCAPE.

The strong longwave trough now located north of Montana will
continue east and drive a cold front into MN Friday. Wind shear
will increase in the afternoon to support supercells along the
front - all to the northwest. Instability may limit coverage of
storms, and it will be most intense to the northwest. Areas north
and west of La Crosse may see this activity in the evening, with
higher chances in north-central WI. This will need to be
monitored, as it could pose an isolated severe storm threat Friday
evening /wind, hail/. Confidence in the coverage and timing is
limiting an upgrade in severe weather messaging /and SPC from
upgrading to a slight risk/. Further north, closer to the
attendant forcing, has the best potential.

.LONG TERM...(Friday night through Thursday)
Issued at 235 PM CDT Thu Jul 25 2019

Cold frontal boundary from Friday hangs up across the area for
Saturday, and the results in the model guidance are mixed on IF
this boundary generates storms, but it seems to be trending. The
boundary in the NAM /which goes bonkers with storms/ has ~2500
J/Kg of MLCAPE that could be uncapped and need only a bump with
weak frontal convergence. This is mainly WI and have increased
rain chances Sat aft/eve. Isolated pulse severe storms cannot be
ruled out.

Sunday brings more dynamics to the region and consensus on
increasing storm trends with a moderately strong shortwave trough.
Moisture transport into a developing warm front shifting
northward looks to provide elevated instability. This warm front
could be active in the afternoon for areas north and west of La
Crosse, with storms shifting southeast Sunday night. A bit too
early to discern severe weather threats but definitely on our
radar to monitor :)

Monday through Thursday...

Looking out into next week, the upper level ridge is expected to
remain over the Rockies putting the Upper Midwest into a weak
northwest flow pattern. There are some differences between the
25.00Z ECMWF and 25.12Z GFS on how amplified this pattern will be
which will impact the potential track of a short wave trough topping
the ridge. The ECMWF shows a less amplified flow than the GFS and
brings this short wave trough across the region. The GFS with a more
amplified pattern dives the short wave trough well to the southwest
of the region. Both models are showing convective development ahead
of this short wave trough over the High Plains Monday night that
looks to upscale into a MCS. With the differences aloft, the ECMWF
brings this MCS into and across the southwest sections of the area
Tuesday night/Wednesday while the GFS drops this through the
Missouri River Valley. For now, to reconcile these differences, will
have some rain chances across the southwest half to three-quarters of
the area late Tuesday night into Wednesday morning.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1058 PM CDT Thu Jul 25 2019

A short wave trough will produce showers mainly south of
Interstate 90 overnight. Due to this, did not include them in the
TAFS. While the precipitation will not impact them, there will be
a broken mid and high deck of clouds.

On Friday, another shortwave trough will move through northern
Minnesota and northern Wisconsin. This will bring another round
of mid and high clouds. These clouds will mainly impact the KLSE
TAF. Any showers and storms will be mainly north of Interstate 94
this afternoon and evening.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...Baumgardt
LONG TERM...04
AVIATION...Boyne




Area Forecast Discussion

National Weather Service Detroit/Pontiac MI

 651 PM EDT Thu Jul 25 2019


.AVIATION...

Clear and nearly calm conditions will persist overnight with high
pressure centered over the region. Light southerly flow will emerge
with some scattered flat cumulus developing during the late morning
and early afternoon on Friday. Lake breeze boundaries with a little
bit of enhanced cloud may make further inroads for the Detroit area
terminals during the late afternoon, as the broad pressure gradient
will provide less resistance to inland propagation.

.DTW THRESHOLD PROBABILITIES...

* Low confidence in ceilings around 5kft with lake breeze boundary
  Friday 20-23z.

&&

.PREV DISCUSSION...
Issued at 344 PM EDT Thu Jul 25 2019

DISCUSSION...

Deep column ridging is in place directly over Southeast Michigan
with anticyclonic flow trajectories from the surface through 20 kft
agl. Plan view progs throughout the vertical show a coherent
circulation with a stacked center near the Thumb by this evening.
Splendid summertime weather for all of Southeast Michigan with
surface dewpoints in the middle to upper 50s. There is some slight
model signal that suggests an isolated shower could be possible
within the enhanced lake convergence zones particularly for the
corridor from Detroit northward through Port Huron. RAP and HRRR
soundings show some potential for a parcel to squeeze by the
inversion at 12.5 kft agl. Given nil synoptic support for ascent and
lack of cumulus field this afternoon over the area will forgo any
change/introduction of PoPs to the eastern forecast area.

Center of midlevel high pressure will push east of Southeast
Michigan for Friday. The area will remain under dry southeast flow
throughout the day, therefore, not expecting any significant
difference in weather conditions. It is interesting to note that
some drier midlevel air will lift into the state during the late
afternoon and evening which will help in maintaining stability in
the 10.0 to 15.0 kft agl layer. Dewpoints should creep up a couple
of degrees for all areas as some shallow Lake origin moisture will
be advected into the area, as well some some slight moderation of
airmass with temperatures. High Friday are expected to be in the
middle 80s.

Warming of both surface temperatures and dewpoints will occur on
Saturday as southwesterly return flow finally washes back across
Southeast Michigan. However, midlevel moisture will be lacking with
only a narrowing plume of 800-600mb theta e folding down across the
area during the late afternoon hours. The uncertain aspect of the
forecast really comes down to what precipitation chances and timing
be on Saturday. Currently, it appears not that favorable as strong
capping is forecasted at roughly 800mb. High temperatures are
expected to reach the upper 80s to around 90 degrees.

Low-level jet oriented southwest to northeast across the Midwest
into the Great Lakes to strengthen Sunday into Monday which will
allow a push of even warmer air to enter SE MI, marked by h850
temperatures increasing to an average of 18-19C (from 16C on 18Z
Sat). This will allow daytime highs to peak in the mid to upper 80s
for most locations across SE MI and potentially the lower 90s across
the urban Metro region. Operational GFS and MOS output less
aggressive regarding the chances to hit upper 80s/lower 90s, but
GEFS ensemble mean suggests otherwise. A series of weak upper-level
waves are expected to ripple across the region throughout Sunday
which will bring the slight chance to see pop-up showers and storms.

Low pressure across the northern Plains will travel northeast over
Lake Superior on Monday which will drag a cold front Michigan
sometime between Monday morning and evening. Given the current
projected timing of the front and strengthening LLJ ahead of the
boundary, temperatures will have another chance to peak in the mid
to upper-80s (especially over the urban Metro area). Plenty of room
for adjustment regarding timing of the front so additional tweaks
may be needed for temperature highs on Monday. Otherwise, the best
chance to see rain showers and thunderstorms will be tied to the
cold front Monday afternoon and evening. Increase in low level winds
with diurnal mixing could also make for breezy conditions Monday
morning and afternoon with potential gusts between 20 - 30 mph.

Behind the cold front a sprawling high pressure system will fill in
from the Plains, eventually settling over the Great Lakes region.
This will bring an extended period of dry weather Tuesday into late
next week. The front will also act to return temperatures to
normal/slightly below normal values with highs in the low to mid-80s
(cooler in the Thumb).

MARINE...

High pressure remains in control over the marine conditions through
the end of the week with dry weather and light winds bringing
favorable marine conditions through Friday. There will be an
increase in southwest winds with gusts of 15 to 20 knots on Saturday,
especially across Saginaw Bay and central Lake Huron, late Friday
night into Saturday as pressure gradient tightens ahead of a weak
cold front sagging south across the northern Great Lakes. This front
will also bring a chance of showers with a few thunderstorms mostly
across northern and central Lake Huron on Saturday. This front will
stall across southern Lake Huron and sag slightly further south into
Lower Michigan by Sunday. Another uptick in southwest winds as a low
pressure system moves over Lake Superior.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....Mann
DISCUSSION...CB
MARINE.......AA


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.




Area Forecast Discussion...UPDATED

National Weather Service North Platte NE

 909 PM CDT Thu Jul 25 2019

.SYNOPSIS...
Issued at 332 PM CDT Thu Jul 25 2019

H5 analysis from earlier this morning had high pressure
over northeastern New Mexico. North of the high, a closed low was
located over central Saskatchewan. A weak shortwave trough of low
pressure extended from northern Minnesota into portions of central
Nebraska. This feature has led to mid level cloudiness and showers
earlier today. This activity has since moved east of the area with
dry conditions noted across the forecast area. Skies were
generally clear across north central Nebraska, while a shroud of
mid to high level cloudiness extended from the southern Nebraska
Panhandle, east across the southern third of Nebraska. At the
surface, a weak frontal boundary was situated from west of
O`Neill, southwest to just southeast of Thedford, then west
southwest into northern Colorado-just south of the NE/CO border.
Temperatures as of 2 PM CDT, ranged from 81 at Broken Bow to 90 at
Valentine.

&&

.UPDATE...
Issued at 908 PM CDT Thu Jul 25 2019

A mature MCS is underway across sern Colo and swrn KS this evening
and this should stabilize swrn Nebraska. A forecast update is in
place which removes any rain chance across swrn Nebraska tonight.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 332 PM CDT Thu Jul 25 2019

Fairly quiet weather conditions are expected across western and
north central Nebraska over the next 12 to 18 hours. Low pressure
aloft over southern Canada will track east overnight. The frontal
boundary will remain stalled across the central Sandhills. With
little or no forcing aloft and good subsidence on the western axis
of the northern stream low and trough, dry conditions will be
expected for the bulk of the forecast area. Some isolated
convection will develop on the northern and nern periphery of the
upper level high over northeastern New Mexico. Some of this
activity may clip the far southwestern forecast area this evening
and have placed a slight chance pop in western Chase county
through mid evening. Across far northern Nebraska overnight, the
NAM12 and HRRR are indicating some convective development toward
12z Friday. After chatting with UNR, it was decided to insert some
low pops overnight across far northern Nebraska. For the first
half of Friday, the frontal boundary will lift north into northern
Nebraska, stalling there in the afternoon. Moisture will pool
along the frontal boundary with PWATS eclipsing 1.5 inches by 21z
Friday. At the same time, an upper level disturbance will approach
the forecast area from the northwest. With surface heating along
the front and steepening lapse rates, thunderstorm development is
possible INVOF the front late Friday afternoon into Friday
evening. Deep layer shear is on the order of around 30 KTS, which
could favor strong to low end severe storms. ATTM, the greatest
threat is over the Sandhills and into north central Nebraska and
have included some low end pops accordingly.

.LONG TERM...(Saturday through Thursday)
Issued at 332 PM CDT Thu Jul 25 2019

The upper level high across the sw CONUS will retreat west
Saturday. At the same time a decent shortwave trough of low
pressure will traverse southern Canada forcing a cold front into
the area Saturday night. Showers and thunderstorms will develop
along the front Saturday night as it passes through western and
north central Nebraska. After 90s on Saturday, readings will cool
back into the 80s for Sunday and Monday. The upper level high and
ridge will build east on Tuesday, with warmer temperatures
arriving mid week next week with readings back in the 90s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 618 PM CDT Thu Jul 25 2019

VFR conditions expected through Friday afternoon at the TAF sites.
Concerns in the near term will be two distinct low confidence
chances at rain and thunderstorms. Late tonight isolated to
scattered thunderstorms may develop off the Black Hills. Should
these occur, steering flow will push them into GRN and VTN area
overnight. Think greatest potential for these storms is north of
the area so will cover with a VCTS for now at VTN. Then, scattered
thunderstorms are possible along the surface boundary Friday
afternoon. Precise location of boundary is low for now, but
current thinking is placement will favor northern Sandhills and
thus highest probabilities of storm development in that local
area. Will again defer to later forecasts and cover idea with VCTS
at VTN for now.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...CDC
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Jurgensen




Area Forecast Discussion

National Weather Service Twin Cities/Chanhassen MN

 1019 PM CDT Thu Jul 25 2019

.UPDATE...
Issued at 1019 PM CDT Thu Jul 25 2019

Updated to include 06Z aviation discussion below.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 245 PM CDT Thu Jul 25 2019

A pronounced circulation (noted by regional satellite imagery) over
southwest Minnesota early this afternoon, was associated with
convection that occurred in South Dakota overnight. There remains
enough energy with this circulation to continue high chance
percentages in south central Minnesota through the late afternoon.
However, instability is weak, and lapse rates are not conducive for
anything more than an isolated storm. Farther to the northwest
across far eastern North Dakota/northwest Minnesota, the combination
of modest instability along the surface front, and upper level
energy from a storm system in south central Canada, has led to a
line of showers and thunderstorms to form this afternoon. This area
of convection will likely move east/southeast during the late
afternoon/early evening before becoming weak and disorganized as it
runs into weaker instability. There is enough surface convergence
along the front to continue chance percentages in west
central/central Minnesota this evening. Slowly the area of
convection will move southeast across southwest, and into east
central Minnesota toward early Friday morning. Severe weather will
be limited to areas of west central Minnesota before 9 pm.

Precipitation will likely weaken Friday morning before reforming
late Friday afternoon along the slowly moving frontal boundary. This
boundary will likely washout in southern Minnesota Friday evening
setting the stage for isolated storms on Saturday. Temperatures will
be dependent on how much sunshine develops once the precipitation
stops/weakens Friday morning and skies become sunnier. The best
chance of 90s will occur in west central Minnesota, with 70s/80s in
west central Wisconsin where the cloud cover will likely hold. Due
to the proximity of the weakening frontal boundary Friday night, I
can`t rule out isolated showers or storms. However, most of the
energy with the storm system moving across south central Canada
today, will have moved farther away to have little affect in our
region for large scale lift.

.LONG TERM...(Saturday through Thursday)
Issued at 245 PM CDT Thu Jul 25 2019

Forecast concern in the longer term remains convective potential
Saturday afternoon to the south, developing again later Saturday
night and continuing into Sunday Night. Trend is cooler early
next week with a warming trend late in the week.

Frontal boundary associated with Friday night convection is
forecast to exit to the southeast Saturday afternoon. This should
take the chance of thunder with it. Timing may still be an issue
with The GFS a bit slower and may continue at least a small threat
over the far southeast CWA in the afternoon. We continues the dry
trend for now.

This remains short lived however, as the deterministic models
drive another potent short wave trough over the upper ridge across
the CWA Saturday night into Sunday night. The GFS is a bit faster
and pretty much brings a rainy day for the region for Sunday.
This will likely affect overall instability and significant
thunder threat. If this system is slower, closer to the ECMWF, we
could see warmer temperatures, especially across the south with
some lower 90s a possibility Saturday afternoon.

Following the front, cooler and drier high pressure should
dominate the weather through Wednesday. We could see a threat of
showers/isolated thunder skirt mainly the southwest CWA Tuesday
night as a weaker short wave travels across that region, closer to
possible stationary boundary southwest of the state. The GFS is
drier with this system.

Both the GFS and ECMWF begin to build heights across the western
CONUS the second half of next week. The ECMWF is a bit warmer as
it builds in higher heights by Friday. The GFS continues to leave
the CWA in the transition zone with the stationary/warm front
remaining mainly west of the area with leaving us in weak
northwest flow and possible shower/thunder threat returning with
frontal passages.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1019 PM CDT Thu Jul 25 2019

Convection has had a tough time developing southward along the
instability axis to our west this evening, but there are some
indications that a few storms could develop over night (in the
HRRR and some other CAM solutions). However, don`t have enough
confidence in development, particularly with the expecation that
coverage would be limited even if storms develop, to include too
much mention in the TAFs at this point. However, updates could
certainly occur if/when the atmosphere shows its hand. Still look
to have another chance later in the day on Friday when the frontal
boundary moves through the area, but most of the guidance suggests
limited coverage with that activity as well.

KMSP...Main concerns continue to be with chance for SHRA/TSRA late
tonight and again late Friday afternoon. Will need to keep an eye
on it and update if needed, but otherwise didn`t see a need to be
too pessimistic at this point.

/OUTLOOK FOR KMSP/
Saturday...VFR. North to northwest wind 5 kt or less.
Saturday night...VFR. Variable wind less than 5 kt.
Sunday...MVFR possible with a chance of SHRA/TSRA. Southeast wind
5 to 15 kt becoming southwest.
Sunday night...MVFR possible with a chance of SHRA/TSRA. Southwest
wind 5 to 15 kt becoming northwest.
Monday...VFR. Northwest wind 10 to 15 kt.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

UPDATE...
SHORT TERM...JLT
LONG TERM...DWE
AVIATION...