Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/26/19
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
835 PM CDT Sun Aug 25 2019
.DISCUSSION...Once again this evening, convection fired into
fairly robust clusters of strong to severe storms, with the most
intense causing wind damage in western Willacy County where radar
was estimating 70+ mph winds as the microburst surged through. That
was the second act of a tornadic mini-supercell in western Kenedy
County with eerie similarities to June 24th, the "sequel" to the
2018 Great Flood. That`s where the similarities ended,
fortunately, as plume and push of very dry mid level air won the
battle...and will set the stage for continued heat (and a likely
new August monthly heat record for much of the RGV) for much of
the upcoming week, along with largely rain-free weather.
That rain-free trend begins overnight...based on the "worked over"
atmosphere this evening and the filtering of the deeper dry air
later tonight. Given these trends, have reduced precipition
gradually this evening, and cut off completely by 10 PM - with the
main leftovers "debris" stratiform rain in the Lower Valley
through the western Gulf.
No changes for Monday...but as previously mentioned the heat will
surge in low level south to even southwesterly (off the deck) flow
with thicknesses well above average. Plenty of surface RH as well
so advisories are looking more likely...and would not surprise if
readings edge over 115 for several hours and require warnings
particularly across the RGV if mixing of drier air higher up can`t
erode the surface dewpoints enough. Stay tuned.
No further changes...digital forecasts have been published and
text products to follow shortly.
Update - 52/BSG
&&
.AVIATION...Apologies for the late discussion on the 00Z forecast
but elected to combine overall discussion into one based on
gridded forecast changes as well as tracking/following up with the
strong/severe thunderstorms for a few hours earlier. After
adding convection into the TAFs through 8 PM, overnight will see
anvil cirrus for several hours which should become scattered after
midnight. Surface winds were disrupted by the convection but will
come back to a less than 10 knot average overnight. Could see
patchy MVFR conditions but expect only very short periods of
ceiling if at all.
As the aforementioned atmospheric dry air spreads south on Monday,
forecast shifts to a wind-cast as atmospheric RH values drop
noticeably. This should keep clouds to few-scattered MVFR cumulus
all day. South to southeast winds will pick up quickly by mid to
late morning and a pretty gusty afternoon is likely with sustained
winds edging to 20 knots or so as thermal trough enhances the
pressure gradient.
52/BSG
&&
.PREV DISCUSSION... /issued 322 PM CDT Sun Aug 25 2019/
SHORT TERM (Now through Monday Night): Another round of showers and
thunderstorms is underway, as a weak mid-level trough persists
across the Western Gulf and the diurnal seabreeze develops just
inland. Radar imagery indicates numerous convection across Brooks
and Kenedy counties, as well as the lower RGV. High-resolution
convective models are in pretty good agreement with this convection
expanding and moving gradually west-southwestward across Deep South
Texas through the evening. The HRRR in particular has been fairly
consistent, showing a few stronger cells possible. Though a
marginally-severe storm cannot be ruled out, heavy rain will be the
main threat this evening. 12Z KBRO sounding from this morning
measured record-level moisture, with precipitable water values of
2.41 inches. This will undoubtedly lead to locally heavy downpours
with torrential rainfall rates. Most of the region is under drought
conditions, however, any rainfall rates exceeding 1 to 2 inches per
hour would cause some flooding issued in low-lying and urban areas.
Tonight into Monday, the mid-level trough will pivot northeastward
away from the region. Drier air will then filter back in, keeping
rain chances low the rest of the period. The heat will continue with
mid-level heights around 591 to 592dam along with surface dew points
in the mid to upper 70s across the RGV. This will lead to heat
indices exceeding 110 for much of the area and up to 115 across the
inland coastal counties and lower RGV. Therefore, another Heat
Advisory will be likely tomorrow.
LONG TERM (Tuesday through Sunday): Latest NWP guidance remains
rather consistent with previous forecast through the long-term,
with perhaps some changes in sight by later next weekend. On
Tuesday, 500-mb high center will lie roughly near ELP, with ridge
axis extending into the western Gulf of Mexico. The center of this
subtropical high is progged to drift gradually westward through
Friday, before drifting northward next weekend. This will maintain
rather hot and humid conditions through Thursday, with only very
slight (silent) rain chances. Should note that the ECMWF still
holds the ridging somewhat stronger vs. the GFS during this
period. Will continue to lean in the ECM`s direction, per
continuity with previous forecast.
With little change in guidance, both temps and PoP`s were left
largely alone for this package. Still looks like a Heat Advisory
may be required on Tuesday, with heat indices reaching into the
110-114 degree range across much of the CWA. Thereafter, slowly
receding heights and gradually backing/weakening winds (south of a
front stalled out over east/northeast Texas) should take a little
edge off of the heat, with temps closer to climo norms by around
Friday.
For Friday, and perhaps more so into next weekend, another
weakness aloft develops with the high center well off to the
northwest. This should allow column RH to deepen, with a slight
chance of sea-breeze showers and storms on Friday, increasing to a
chance for next Saturday and Sunday. 12Z run of ECM appears to
have come into better agreement with GFS on this, after taking a
quick look. Speaking of the ECM (and looking way ahead), last
night`s 00Z run wanted to bring a frontal boundary, with plenty of
moisture, through the area around Labor Day (02 Sep). 12Z run
brings a tropical circulation of some sort into the western Gulf
from the east around this time. So confidence isn`t especially
high beyond Saturday. Have trended PoP`s up to around 30% in this
timeframe for now, though.
MARINE (Now through Monday Night): The pressure gradient has
tightened a bit today as pressure decreases across the TX Panhandle,
leading to stronger southeast winds along the Bay today. Small craft
will need to exercise caution the rest of the afternoon and into
tonight as winds remain elevated. Moderate winds are expected again
on Monday along with low to moderate seas across the Gulf waters,
though thunderstorm chances will quickly diminish through Monday and
Monday night.
Tuesday through Saturday: Still anticipating moderate-to-fresh
south-to-southeasterly breezes and generally moderate seas around
4 feet on Tuesday, courtesy of an enhanced pressure gradient.
Small Craft Exercise Caution wording will likely be needed Tuesday
daytime on the Laguna Madre and perhaps on the nearshore Gulf
waters as well. The pressure gradient will then become weaker
through the rest of the period, as a front stalls across north
Texas, resulting in light to modest southeasterly winds and
favorable seas. At times, rain showers and isolated thunderstorms
will be possible starting Wednesday, generally offshore, then
expanding to all of the coastal waters beginning Thursday. There
could be locally higher winds and seas in any storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 81 96 82 95 / 20 10 10 10
BROWNSVILLE 81 100 82 97 / 30 10 10 10
HARLINGEN 81 100 81 100 / 20 10 10 10
MCALLEN 82 103 82 102 / 40 10 0 10
RIO GRANDE CITY 81 104 81 103 / 30 0 0 10
SOUTH PADRE ISLAND 82 91 83 90 / 20 10 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
52/99
Area Forecast Discussion
National Weather Service Quad Cities IA IL
905 PM CDT Sun Aug 25 2019
.UPDATE...
Issued at 905 PM CDT Sun Aug 25 2019
Area radars show widespread showers expanding in coverage over
most of the forecast area in response to elevated moisture return
and warm advection, combined with strong upper forcing ahead of
a shortwave. At 8 pm, this shortwave was moving through south
central IA and central MO with a well defined swirl on radar over
northern MO and a weaker, possible MCV moving into southeast IA.
The bulk of lightning has been associated with the main vort max
over MO, but there have been some isolated flashes over southeast
IA due to the strong upper level lift and associated enhanced mid
level lapse rates.
Have updated the forecast to increase rain chances and coverage
this evening and overnight over the forecast area and kept
isolated thunderstorms mainly along the highway 34 corridor. The
best lift will shift to east of the MS River after midnight into
Monday morning and have increased pops over that area to likely
and categorical. Rainfall rates support widespread quarter to half
inch rainfall in this area. Models are coming into decent
agreement with the current weak surface low, currently setting up
near Kansas City, migrating northeast through southeast Iowa into
west central IL by mid morning. This would place northeast MO and
southeast IA in the prime spot for low level moisture pooling and
fog, as indicated by the SREF and recent HRRR runs. Have thus
added a mention late night early morning fog into the mix for
these areas.
&&
.SYNOPSIS...
Issued at 246 PM CDT Sun Aug 25 2019
18Z surface data has high pressure from New England back into the
eastern Great Lakes. Dew points were in the the 50s from the Ohio
Valley into the Great Lakes with 60s across the central and northern
Plains. Dew points in the 70s were in the southern Plains into the
deep South.
&&
.SHORT TERM...(This Evening through Monday)
ISSUED AT 246 PM CDT Sun Aug 25 2019
Return flow aloft combined with weak forcing will allow sprinkles
and showers to persist through sunset.
Tonight forcing will slowly increase as an upper level disturbance
from the Missouri storm complex slowly moves northeast. This
additional forcing combined with moisture flowing into the area
should allow isolated to scattered showers to continue overnight
with the better coverage generally east of the Mississippi. Rainfall
amounts however will be less than one tenth inch.
Monday has the potential to be interesting.
Lingering showers are expected through the morning hours with the
better coverage east of the Mississippi.
Monday afternoon the next cold front will move into the area during
peak heating. Moisture and forcing will be plentiful so
thunderstorms are expected to develop along and ahead of the front.
The severe potential is acknowledged given the forcing and favorable
winds aloft. However if cloud cover persists through the day, which
is possible, then it may greatly reduce the overall severe
potential.
.LONG TERM...(Monday Night through Sunday)
ISSUED AT 246 PM CDT Sun Aug 25 2019
Monday night through Thursday, Showers and Thunderstorms will end
overnight Monday with pleasant weather on tap for much of the
upcoming week. The upper level flow over the central U.S. will shift
to the northwest in response to a deep upper level closed low
developing north of the Great Lakes and an upper level ridge
building over the inter-mountain west. Skies will be mainly sunny
through the period as cool surface high presssure builds into the
the midwest, ushering in below normal temperatures. Highs will be in
the mid to upper 70s. Normal highs are in the mid 80s. Overnight
lows will be very cool ranging in the low to mid 50s.
Friday, The next shortwave and associated cold front will approach
the Mississippi Valley. The front may produce showers or
thunderstorms but moisture wiil be limited with this system. There
is uncertainty with the timing of the frontal passage but this will
become clearer as we get closer to the event. Behind the front,
skies will clear and a reinforcing shot of cool high pressure will
build into the mid west. High temperatures will once again be
pleasant with highs in the mid 70s and overnight lows in the 50s.
Labor Day Weekend, Skies should be dry as high pressure settles in
over the area. High temperature will be in the mid to upper 70s with
overnight lows in the mid 50s. Below normal temperatures, along with
a northerly breeze, will make for a fall-like Labor Day weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 629 PM CDT Sun Aug 25 2019
Scattered showers associated with an upper level system will
affect all terminals this evening with prevailing VFR conditions.
Conditions are then expected to deteriorate overnight as an
advancing warm front brings widespread IFR ceilings and
visibilities into MVFR range or possibly lower. There will be a
potential for at least isolated showers through the night. Monday,
the low clouds may linger through much of the day and the
forecast has a low confidence trend improving ceilings from IFR in
the morning to MVFR in the afternoon. Another round of more
widespread showers and thunderstorms is expected to reach the area
by late afternoon, but more likely evening. These are advertised
at all sites with prob30 groups at the end of the forecast period.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Sheets
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Kuhl
AVIATION...Sheets
Area Forecast Discussion
National Weather Service Green Bay WI
633 PM CDT Sun Aug 25 2019
Updated aviation portion for 00Z TAF issuance
.SYNOPSIS...
Issued at 234 PM CDT Sun Aug 25 2019
Scattered showers and thunderstorms at times through Monday
night, blustery and mild on Tuesday, then windy and much cooler
Wednesday.
Slow progression of the large scale pattern is expected for the
next few days as an upper trough pushing into the area from the
west undergoes strong amplification. The trough will slow mid-
week as it closes off into an upper low over western Ontario. The
bulk of the energy within the trough will lift toward northeast
Canada late in the week, leaving weakening cyclonic upper flow
across the area.
The main precipitation event will occur with the frontal system
crossing the area early in the period with only a few rounds of
scattered light showers are expected thereafter. The result will
probably be near to slightly below normal amounts for most
locations. Despite day-to-day temperature variations due to the
passage of individual weather systems, readings will probably end
up near of slightly below normal for the period as a whole.
&&
.SHORT TERM...Tonight and Monday
Issued at 234 PM CDT Sun Aug 25 2019
The latest RAP analysis and satellite/radar imagery show a
sprawling high pressure system departing over the northeast conus
early this afternoon. Onshore southeast flow around this massive
high and daytime heating has produced another day of widespread
fair weather clouds across the region. Meanwhile, southerly flow
aloft ahead of shortwave energy moving over southeast Minnesota
and an MCV over eastern Kansas is pushing higher moisture into
southwest Wisconsin. A narrow band of showers is accompanying the
leading edge of the more moist air, and its possible that some of
these showers will reach into central Wisconsin late this
afternoon or early evening. Will add a slight chance. As shortwave
energy moves into the region, followed by an approaching cold
front late on Monday, forecast concerns revolve around timing
precip chances and whether a severe threat will develop.
Tonight...Weak moisture convergence on the leading edge of the
more moist air will lead to a chance of light showers or sprinkles
over central to north-central WI this evening. Not sure how far
east to carry slight chances of precip, as the moisture
convergence generally weakens through the night. After a brief
lull in the precip chances, the higher resolution guidance
indicates that showers will expand over northern Illinois into
southeast Wisconsin overnight, which will then approach east-
central WI by early Monday morning. No firm consensus on this
scenario, but given the showers over Illinois this afternoon,
think this is a reasonable scenario. Lows will be warmer and
mostly range from the low 50s near the U.P. border to the low 60s
over the southern Fox Valley.
Monday...Details remain murky in general. Many of the higher
resolution models indicate the MCV over eastern Kansas will lift
northeast across eastern Wisconsin during the day. If this occurs,
marginal severe weather chances would become even lower.
Otherwise, much of central and northern Wisconsin stand a decent
bet of remaining dry during the morning. With 400 to 600 j/kg of
cape moving in from the west during the afternoon ahead of a cold
front, chances for thunderstorms will gradually increase across
central and north-central WI. Deep layer shear will also be
increasing into the 30-35 kt for thunderstorms to work with if any
can develop. But with the cloud cover and potential for rain with
the MCV, it is possible that thunderstorms will hold off into the
evening with the approaching front. Temps will be similar to
todays readings, though could be cooler over eastern WI if rain
moves in during the morning.
.LONG TERM...Monday Night Through Sunday
Issued at 234 PM CDT Sun Aug 25 2019
The primary change in the guidance since yesterday has been to
pull back significantly on the precipitation amounts during the
next 36 hours. Timing has slowed a little as well.
The decrease in QPF seems to primarily be related to the speed
with which the primary forcing with the frontal system pushes
through the area, and the fact it is now arriving well after dark.
PWATs are still forecast to rise to AOA 1.5" for a time, so brief
heavy rain is possible with the stronger convection. Although
storm motion may be nearly parallel to the front, the front is
expected to remain progressive. The main hydro issue will probably
be ponding of water if the heavy rain occurs in urban areas.
Gusty winds will be possible with the storms, with the potential
for severe being limited at best.
The default forecast initialization grids based on a broad-based
blend of guidance products seemed reasonable for temperatures. In
addition to QPF adjustments toward the latest guidance, also
adjusted PoPs up some as the upper trough settles into the area
mid-week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 633 PM CDT Sun Aug 25 2019
A storm system remains on track to impact the region from late
tonight into Monday, but details remain murky. It appears that the
system will impact the area in pieces. The first piece may pass
over the Fox Valley and Lakeshore areas in the morning, with rain
and isolated storms, and mvfr cigs/vsbys. More showers and storms
then look possible across much of the area from late afternoon
into Monday night. At this point have placed in PROB30 groups for
the morning across the east then TEMPO groups later in the
afternoon when IFR conditions are possible with heavier showers.
Across the west the best chance looks to be later in the morning
and into the afternoon hours as the main system approaches.
Although thunderstorms will be possible at times, coverage is too
isolated to include in this set of TAFs.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from Monday morning through Tuesday
morning for WIZ022-040-050.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1013 PM EDT Sun Aug 25 2019
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 323 PM EDT Sun Aug 25 2019
- Showers and a few thunderstorms Monday
- 2 inches of rain possible in spots Tuesday morning
- A final shot of precipitation possible Wednesday and breezy
&&
.UPDATE...
Issued at 1014 PM EDT Sun Aug 25 2019
A quick look at some of the 00z data from satellite loops, the 21z
SPC SREF and the 00z RAP model tell me that our overall on-going
forecast is in good shape. It will rain over most of our CWA by
early to mid afternoon. The lead southern stream shortwave, being
forced northward by the income Pacific system, streams
precipitable water values to around 1.9 inches by mid afternoon
into our CWA. The moisture transport vectors from the 00z RAP
still suggest the rain will be over most of our central and
southern CWA by early afternoon. The near 700 mb condensation
pressure deficit falls to near zero mb by 2 pm at Grand Rapids.
The Specific Humidity rises from under 2 g/kg at 8 am to near 8
g/kg by 2 pm at Grand Rapids. The combination of the those two
features alone suggests rain.
The best instability remains over the western CWA and
the most unstable cape does not get over 500 j/kg north and east
of Grand Rapids through 8 pm Monday. Most of the day it stays
under 500 j/kg over the entire CWA. So it`s questionable if we
would have any thunderstorms till mid afternoon and then it would
be south and west of GRR. That matches the SPC SREF 3 hour
thunderstorm probability forecast too.
Bottom line is our forecast overall looks on track.
&&
.DISCUSSION...(This evening through next Sunday)
Issued at 323 PM EDT Sun Aug 25 2019
-- Showers and a few thunderstorms Monday --
Models remain consistent with timing showers and thunderstorms into
the area after sunrise Monday and spreading northeast during the
day. Thunderstorms shouldn`t be widespread but they are a concern.
Forecast reasoning: Instability doesn`t look overly impressive and
there is much dry air to overcome. Still, there is a potent upper
low over the southern Plains that will lift north and a strong upper
PV anomaly crossing Montana that will provide plenty of dynamic lift
and should induce a moisture laden southeasterly low level jet
during the day Monday. The low-level shear is a little troubling in
terms of quick spinups that have a non-zero chance of occurring with
the right type of outflow boundary interaction.
-- 2 inches of rain possible in spots Tuesday morning --
Chances are increasing for brief but intense rainfall Tuesday
morning with local amounts exceeding 2 inches in spots. This could
impact the morning commute and nuisance flooding will also be
possible. The best guess for location is currently from the Muskegon
area northeastward. However, given the localized nature of the
precipitation, we are far from certain exactly where this would
occur.
Forecast reasoning: Focus for rain will be associated with a cold
front and a narrow unseasonably moist plume of moisture ahead of the
front. Deterministic models show a sharp digging upper trough with
attendant strong mid-level frontogenesis resulting from compression
and rotation of the thermal gradient. Precipitation efficiency will
be boosted by high precipitable water values. Rain rates could be
impressive in spots, with 2 inches an hour or more not out of the
question. Fortunately durations at any given location should be
curtailed by the expected steady progression of the front.
-- A final shot of precipitation possible Wednesday and breezy --
We included a slight chance of rain showers mainly north of Muskegon
and near the lakeshore. Timing could be in the morning or in the
afternoon. Rainfall amounts should be light and wind should be quick
to diminish later in the day.
Forecast reasoning: A distinct upper potential vorticity lobe will
sweep east across Lower Michigan at the base of a sharp upper low.
Given the stacked nature of this system, 850 mb temperatures will be
cool, especially farther north, and marginally favorable for lake
enhanced rain. There is some minor disagreement among models
regarding timing of the lobe. What`s more certain is the upper low
exiting the area later in the day to be replaced by dry northwest
flow aloft and a loosening surface pressure gradient.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 724 PM EDT Sun Aug 25 2019
I expect sold VFR conditions through 09z at all TAF sites. After
09z the clouds from the system moving toward us from the south
start moving in. The way this system is moving in, area near and
west of US-131 will see the MVFR to IFR first. The TAF sites near
I-69 will be the last to see those conditions. Rainfall may be
locally heavy near the Lake Michigan shore from late morning into
and through the afternoon. Muskegon is most likely to have IFR or
even LIFR in rain and fog by mid afternoon. Most sites will be at
least MVFR with cigs by 21z. Solid IFR cigs are expected after
00z at all TAF sites.
The risk for thunderstorms Monday at our TAF sites seems rater low
but it is not zero. That is due to the instability not forecast
to be all the high. Also with all the clouds from the system the
afternoon heating will be a non issue, which will also limit the
risk of thunderstorms.
It will become breezy Monday and by afternoon winds at the
surface will be in the 15 to 25 knot range with some gusts to near
30 possible by mid to late afternoon.
&&
.MARINE...
Issued at 323 PM EDT Sun Aug 25 2019
We are increasingly concerned about wind and waves on Wednesday,
which will mark a full day of elevated wind and waves beginning
Tuesday. Showers and thunderstorms combined with cool waters may
limit beach activity Tuesday, but drier conditions and recovering
water temperatures with strong onshore winds Wednesday may be a
different story. As noted before, a small craft advisory will likely
beginning early Tuesday, but will let subsequent shifts hammer out
the details.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...WDM
SYNOPSIS...TJT
DISCUSSION...TJT
AVIATION...WDM
MARINE...TJT
Area Forecast Discussion
National Weather Service Memphis TN
715 PM CDT Sun Aug 25 2019
.UPDATE...
Updated to increase evening rain chances along and west of the
Mississippi River.
&&
.DISCUSSION...
Radar trends show area of convection lifting north across the
southwest Delta counties. This region is still well ahead of an
approaching shortwave crossing the Ozarks...and the associated
lift will keep activity going through midnight along and west of
the Mississippi River. Have updated rain chances accordingly. All
other parameters are currently on track.
JAB
&&
.PREV DISCUSSION... /issued 557 PM CDT Sun Aug 25 2019/
DISCUSSION... /issued 317 PM CDT Sun Aug 25 2019/
A fairly active radar will only likely become more active over
the next hour or two, then storms should begin to decrease in
coverage and intensity late this afternoon. Storms are moving a
bit faster than I expected to see earlier this morning, reducing
the threat of flooding across the area. Nevertheless with
Precipitable water values around 2 inches locally heavy rainfall
is possible and if multiple storms track across the same location
flooding is possible. 20-30 mph wind is also possible from
thunderstorms this afternoon. The threat of severe storms looks
minimal. Most high temperatures across the Midsouth should be in
the middle 80s, but much of the area should get some relief from
rain cooled air and or thunderstorms outflow, knocking
temperatures back down into the 70s.
A few showers may linger through the night with additional
redevelopment tomorrow as temperatures warm back into the middle
80s. It is very hard to predict coverage of storms this time of
year with the lack of any well defined surface boundaries, but at
this time it looks like coverage should be as significant as
today. Highs should be in the middle 80s once again.
Tuesday, a cold front is expected to approach from the North.
Numerous to widespread showers and thunderstorms are expected
ahead and along this feature. The threat of severe storms looks
minimal. It doesn`t look significantly cooler Wednesday through
the remainder of the work week, but a drier airmass will move into
the region. Some dew points may drop into the upper 50s, but most
of us will be in the 60s. Highs will remain in the middle to
upper 80s. However, those lower dew points along with North wind
will make conditions feel cooler. A few showers may linger
Wednesday in North Mississippi, but Thursday and Friday look dry
as surface high pressure settles over the area with weak Northwest
flow aloft.
For the weekend, guidance is in poor agreement. The ECMWF is
wetter featuring a deeper trough over the region with the GFS
maintaining weak Northwest flow. Will feature slight chance pops
for now with near normal temperatures.
30
&&
.AVIATION...
00Z TAF Set
Convection has developed across much of the CWA. The only TAF
site that might escape being impacted this evening is KMEM. HRRR
shows convection eventually shifting to areas of West Tennessee
near the Tennessee River and Northeast Mississippi tomorrow. Will
continue with vicinity wording at KMKL and KTUP for much of the
TAF period. MVFR CIGS will spread over the entire Mid-South by
05-06Z. CIGS will be gradually lift through the day. Winds will
become light and variable this evening. Winds tomorrow will be
from the SSE at 5-10 KTS.
KRM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
639 PM CDT Sun Aug 25 2019
.Updated for 00Z Aviation Discussion...
Issued at 624 PM CDT Sun Aug 25 2019
&&
.SHORT TERM...(This evening through Monday night)
Issued at 245 PM CDT Sun Aug 25 2019
Forecast concern is overall precipitation timing/amounts with
piecemeal trough through Monday evening.
Currently, we have leading short wave trough moving through
western MN generating fairly widespread light showers. Expect this
trend to continue into the evening as it lifts slowly northeast.
Will mention scattered wording for now.
This trough lingers over the northeast CWA into tonight and will
likely hold onto some low end PoP for lingering light showers.
Then timing of next main upper trough continues to slow it
eastward progression. Will bring in higher end PoPs over west
central MN mainly after 06z Mon and then move slowly east to
eastern MN around 12z. Hires solutions continue to bring at least
a line of scattered/broken showers/thunder ahead of the trough
into central MN. The latest iteration of the HRRR continue to back
off on any real higher end PoP overnight and waits really until
near 12z to develop activity to the west. Confidence is low on
that happening at the moment with the HREF and various
deterministic models still driving the activity into at least
central MN by Monday morning. Thunder threat remains rather low
with little instability noted over southern MN in the more
cloudy/showery regime. Will bring chance thunder out west later
tonight/mainly after 06z it appears.
The trough moves into eastern MN Monday morning and we should be
able to generate at least widespread showers over the central and
east much of the day. This will limit temperatures to the upper
60s to lower 70s for highs.
QPF remains similar in overall placement but models continue to
diverge on overall amounts. We came out with a pretty much
widespread 1 to 1.5 inch accumulation for the event across the
northern 2/3rd of the CWA. Still wouldn`t be surprised to see
some 2 inch totals where the upper trough/deformation remains
longest. Placement on this would be from around Willmar/St Cloud
to Little Falls area. Another secondary max could develop into
west central WI into Monday afternoon as the main trough moves in.
.LONG TERM...(Tuesday through Sunday)
Issued at 245 PM CDT Sun Aug 25 2019
Well-defined cold front will be situated over the Great Lakes to
the lower Mississippi River Valley by daybreak Tuesday morning
with the bulk of the precipitation off to the east. The surface
low over far east-central Manitoba province will continue to
slowly slide northeast across Hudson Bay Tue-Thu, with a trailing
weak surface trough expected to swing east over northern MN/WI Tue
into Wed. This will result in some scattered weak instability
showers underneath the cold pool Tuesday afternoon. Some of these
showers may produce up to around 0.10" QPF, particularly north of
I-94. The precip looks to end by Tuesday evening then dry
conditions are expected for Wednesday with precipitation remaining
north of the WFO MPX coverage area. In addition to the showers,
breezy conditions can be expected Tuesday into Wednesday with a
tight pressure gradient setting up over the area between the
departing potent low pressure system and incoming high pressure
from the west.
High pressure will then prevail across the north-central CONUS
from late Wednesday on through the weekend. A weak cold front will
drop through the region late Thursday into Friday, but this will
be a dry front, with dry conditions continuing through next
weekend. Temperatures will generally remain below normal, with
highs around 70 every day except Thursday which will have highs
hit the mid-to-upper 70s in advance of the dry cold front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 624 PM CDT Sun Aug 25 2019
Primarily VFR with dry conditions, but could see a few MVFR
ceilings and light sprinkles this evening and overnight. On Monday
an area of rain will spread across the region from the southwest,
and should have clouds lower as well. There is enough instability
to mention thunder in the tafs on Monday. Should see ceilings lift
from west to east during the evening.
KMSP...
Did push back the timing of MVFR clouds since the guidance seems
to be a little to quick based on the current trends. It also
appears like the best chance for thunder will be during the early
afternoon. Could see VFR conditions return Monday evening.
/OUTLOOK FOR KMSP/
TUE...VFR with afternoon MVFR/-SHRA possible. Wind W at 20G30 kt.
WED...VFR with MVFR possible. Wind NW at 15G25 kt.
THU...VFR. Wind WSW at 10G20 kt.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...DWE
LONG TERM...JPC
AVIATION...JRB