Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/17/21
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
629 PM CDT Fri Apr 16 2021
.UPDATE...
Issued at 624 PM CDT Fri Apr 16 2021
The forecast is on track this evening. No major changes are
planned.
&&
.SHORT TERM...(This Evening through Saturday Afternoon)
Issued at 229 PM CDT Fri Apr 16 2021
The forecast challenge is when/where some of the light returns on
the regional radar mosaic might produce "measurable" (0.01in or
more) precipitation between now and appx 09Z tonight.
Currently, skies are cloudy and there are pockets of light returns
on regional radars. Winds are generally light out of the north at 10
to 15 mph. Temperatures have been holding steady in the low to mid
40s across much of the CWA, so far today.
Models appear to be getting a better handle on the mid/upper level
longwave trof/shear axis working southeastward across Montana and
North Dakota, and as such have been generating pockets of light
precipitation working southward through the CWA from now right on
through the middle of tonight, before the subsidence/backside of the
upper trof axis works over the CWA. Made some minor adjustments to
the chnc/slt chnc pops to extend them further out in time during the
overnight hours before terminating them by Saturday morning. For
much of the day, the hourly updates from the RAP have continued to
support a clearing trend in the cloudcover later tonight into
Saturday, and the short-range digital aviation guidance showcased
this, as well. So, that is currently being carried for skycover in
the short term, a continuation of what has been being forecast for
late tonight/Saturday. The rest of the short term forecast is dry,
with a warming trend noted through Saturday night, while low level
WAA kicks in and draws a warmer airmass into the region.
.LONG TERM...(Saturday Evening through Friday)
Issued at 229 PM CDT Fri Apr 16 2021
The long term begins on Sunday with mild temperatures moving into
the region ahead of a strong cold front. 925 mb temps reach +9 to
+13C across the CWA at 18Z, which combined with westerly flow should
produce highs in the upper 50s, to the mid 60s. Temperatures will
fall quickly behind the passage of the cold front as 925 mb temps
drop 7 to 11C in about three hours. Low level frontogenesis, along
with upper level jet support should bring measurable pcpn to the
CWA. The pcpn may begin as rain before changing over to snow Sunday
night into Monday morning. Snowfall amounts of a dusting to an inch
could be possible, with the higher amounts occurring over the
terrain areas of the Prairie Coteau.
Below normal temperatures can be expected through the middle of next
week as 925 mb temps remain in the single digits on either side of
zero. A weak shortwave, along with steep lapse rates could cause
isolated to scattered showers on Tuesday. Low level temperatures
could be cold enough for a rain/snow mix.
A surface high pressure slides southeastward across the region on
Wednesday, bring dry, and slightly below normal temperatures. Warm
air advection develops behind the high pressure on Wednesday night
with highs rebounding to above normal on Thursday. Another cold
front may pass through the region Thursday night into Friday.
Differences amongst models leads to low forecaster confidence on
Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 624 PM CDT Fri Apr 16 2021
Terminals KABR,KATY,KPIR,KMBG
A mix of VFR and MVFR cigs will continue through the next 24
hours.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...Dorn
LONG TERM...SD
AVIATION...Wise
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
642 PM CDT Fri Apr 16 2021
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Daytime heating has helped mix out the low cld decks
this afternoon allowing for VFR conditions to prevail across the
RGV airports. As the cold front sags southwards towards the region
later tonight through Sat morning, the ceilings will lower down to
IFR levels with the ceilings struggling back to MVFR towards the
end of the 00Z TAF period. Strong and gusty northerly winds will
develop in the wake of the fropa during the latter half of the
forecast period. There will also be a window of opportunity for
isold to sct TSRA throughout Sat morning close to the best surface
convergence associated with the cold front. Will handle this
conv potential with PROB30 groups in the current TAF package.
AWW`s may be needed later tonight into Sat morning for the HRL/BRO
airports due to the anticipated conv activity.
&&
.PREV DISCUSSION... /issued 448 PM CDT Fri Apr 16 2021/
DISCUSSION...Updated for latest marine discussion below.
MARINE...Have posted the SCA for both the Bay and Gulf Waters in
anticipation of the increase in the winds and seas after the fropa
tomorrow morning.
PREV DISCUSSION... /issued 328 PM CDT Fri Apr 16 2021/
SHORT TERM (Now through Saturday Night): After about ten days of a
summer temperature and humidity preview, it all comes to an abrupt
halt for the weekend as a late season strong cold front (for mid
April) sweeps across the Valley late tonight into early Saturday,
with much below average temperatures continuing right through Sunday.
Bottom lines up front are two-fold: The season`s first substantial,
though local, significant thunderstorm activity, followed by feels
like temperatures that could be nearly 50 degrees colder at 3 PM
Saturday than 3 PM today (Friday).
First, thunderstorms. Convective Allowing Models (CAMs) have
localized the larger scale set-up arriving late tonight, which
features the combination of upper-level divergence and some positive
vorticity in west-southwest flow at the base of flat trough across
the southern Rockies, with low level upslope flow into the Sierra
Madre and low level convergence of northeast vs. southeast flow
along the leading edge of the front. This should induce rapid onset
convection just west of the river and Zapata County soon after
midnight, which will then press east and southeast into the upper
Valley and potentially into western Hidalgo County by or just after
daybreak. CAMs are in shifting camps, but the gist suggests
initial, potential supercellular events coalescing into a mini-MCS
as the episode moves down river. SPC has these areas straddling 12Z
for "marginal" threat, mainly hail, as the primary convection will
be elevated immediately behind the surface wind shift to
north/northeast. However, National Water Model data working off the
HRRR suggest potential for up to 5 inches of rain in a couple hours,
which could cause minor flash flooding given the hilly terrain of
western Starr/Zapata, despite the very dry soils. Past experience
suggests that rainfall *rate* is a larger factor when it comes to
minor flood potential. Given uncertainty and localized nature of
the threat, did not include in the gridded forecast, but mentioning
here for situational awareness.
After daybreak, the front will dominate and cooler air will begin
rolling in, stabilizing the low level and ending the severe and even
the overall thunderstorm threat for the more populated lower/mid
Valley region Saturday morning. Thereafter, it`s a nasty day
(unless you`re looking for the refreshing break to the soupy
heat/humidity), with brisk north/northwest wind and temperatures
falling into the upper 50s to lower 60s everywhere by early to mid
afternoon. Lesser rain and raising ceilings may bring temperatures
back toward the mid 60s across Zapata/Jim Hogg/Starr.
Overcast Saturday night with continued patchy light rain (west) and
a bit steadier (east) will combine with the last of the cold
advection to ease temperatures down into the low to mid 50s in all
areas by daybreak Sunday.
LONG TERM (Sunday through Friday): Cold-air damming behind
Saturday`s cold front will continue on Sunday, keeping
temperatures well below seasonal normal (about 15-20 degrees
below). Showers will be ending west-to-east through the day on
Sunday. However, model consensus shows weak coastal troughing
developing Sunday night, into Monday morning. This will keep
slight rain chances (10-20%) in the forecast late Sunday night
through the day on Monday and possibly into Tuesday, with best
chances occurring near the coast. Weak CAA will continue on
Tuesday, but more sunshine is expected during the afternoon than
previous days. This will allow temperatures to warm up into the
low-mid 80s, closer to seasonal average. Both 12z runs of the GFS
& ECMWF are in slightly better agreement that a weak and dry cold
front will move through the area late Tuesday night or early
Wednesday morning. The effects of this cold front will be almost
unnoticeable, other than slightly cooler temperatures on
Wednesday, as surface high pressure quickly shifts eastward over
the lower Mississippi Valley by Wednesday evening. In turn, winds
will become onshore and return out of the southeast by Wednesday
night. Weak perturbations in the west-northwest flow aloft, ahead
of an approaching shortwave trough from the northwest, may cause
isolated showers Wednesday night and Thursday morning. Lots of
uncertainty with regards to this approaching shortwave on
Thursday/Friday, with the GFS showing a more aggressive and
longer-lasting effects of the shortwave across Deep South Texas.
Isolated to scattered showers and thunderstorm are possible on
Friday if this scenario plays out. However, very low confidence
with the forecast beyond Thursday. More details to come in later
updates.
MARINE (Now through Saturday night): A quiet evening with modest
southeast winds becoming light east will end abruptly toward
daybreak with the front. 20+ knot winds will arrive just prior to
daybreak Saturday morning for all but the Cameron County
coastline...but soon after, 20-25 knot winds and gusty will cover
all waters and seas will crank up rapidly to 7 to 9 feet, with
plenty of rough waves on Laguna Madre. Could see a period of Gale
force gusts, but not enough to require a warning at this
time.Expect some thunder through mid to late morning along and
just behind the front, followed by gusty and nasty light rains
that will continue later Saturday through Saturday night...perhaps
ending across the waters near Baffin Bay late Saturday night.
Small Craft Advisories will be issued this evening to cover the
window right around daybreak Saturday, and these will continue
through Saturday night and beyond. Bottom line? Enjoy this evening
on the water...the remainder of the weekend is not favorable for
boating/fishing activities.
Sunday through Wednesday: Small Craft Advisories will likely be
ongoing Sunday morning, possibly continuing through the afternoon
hours. Gradual improvement of northerly winds and seas will occur
Sunday night into Monday morning. As high pressure settles in
across northern and northeastern Texas Sunday night, mostly
favorable marine conditions will persist Monday through Wednesday,
with light to moderate east-northeast winds and wave heights
generally 2 to 5 feet on the Gulf.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 68 73 58 67 / 30 60 60 60
BROWNSVILLE 70 73 57 66 / 20 60 60 60
HARLINGEN 68 73 55 65 / 30 70 60 50
MCALLEN 68 72 57 66 / 40 70 50 20
RIO GRANDE CITY 65 69 56 68 / 50 70 40 10
SOUTH PADRE ISLAND 69 73 64 66 / 20 60 60 70
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory from 6 AM Saturday to 1 AM CDT Sunday for
GMZ130-132-135.
Small Craft Advisory from 6 AM Saturday to 1 PM CDT Sunday for
GMZ150-155-170-175.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
Short Term/Aviation...60-Speece
Long Term...69-Farris
Upper Air...58-Reese
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1156 PM EDT Fri Apr 16 2021
.AVIATION...
The southeast Michigan airspace will reside within the western
fringe of a plume of higher moisture overnight. This will maintain
periodic or pockets of lower VFR stratus during this time. Should a
window of clearing emerge during the morning period, expect
extensive VFR stratocumulus to develop again during the early
afternoon hours. Winds remain modest through the period.
.DTW THRESHOLD PROBABILITIES...
* Low for ceiling at or below 5000 feet through Saturday morning.
Medium Saturday afternoon.
&&
.PREV DISCUSSION...
Issued at 355 PM EDT Fri Apr 16 2021
DISCUSSION...
1000-500mb geopotential height rises due to a combination of
differential cyclonic vorticity advection and modest mid to upper
level confluence has resulted in background forcing favorable for
subsidence and surface ridging over Southeast Michigan. The layer
suitable for saturation and cloud is shallow between 2.5 and 4.0 kft
agl which negates any potential for shower activity this afternoon.
Latest satellite trends show clear skies over the Saginaw Valley and
also over the far southwest cwa under downsloped trajectories ,
otherwise clouds holding very firm in the Thumb and much of Metro
Detroit. Confidence is not high regarding cloud trends but do
support a more pessimistic cloud trend this evening and tonight for
the eastern cwa.
Subtle mid to upper level shortwave ridging will work across
Southeast Michigan Saturday. Main forecast concern is on sky cover
as it will have a big impact on temperatures. Moist biased Nam is
showing clouds/overcast on Saturday which does have some support for
cloud within the RAP soundings. Projecting forecast highs for
Saturday is tricky with potential clouds and relatively cool air
mass in residence. Did lower readings a degree or two based on some
relatively cooler temperatures residing at the top of the mixed
layer. If clear skies are in place then grids will likely need to be
adjusted upward a few degrees.
Models show a strong trough and cold potential vorticity reservoir
advancing aggressively southward, arriving over the western Lake
Superior shoreline by 00Z Monday. Really looking at a persistence
setup for Sunday with Southeast Michigan wedged between split flow
and modest low-mid ridging. System relative progs support more in
the way of isentropic downglide with favorable dry easterly
trajectories. Expecting warmer temperatures Sunday afternoon based
on mixing heights of roughly 2000 ft deeper. Highs are expected to
reach 60 degrees in most areas.
Models are showing consistency in bringing a sharp cold front invof
Southeast Michigan with 850mb temperatures differing by as much as
12C across Lower Michigan by early Tuesday. EPS members and
Operational ECMWF are forecasting a strong shortwave tracking in
from Northern Canada and taking on a neutral tilt over the northern
Mississippi River Valley or western Great Lakes on Tuesday.
Maintained the inherited Likely PoPs for Tuesday night with a
prevailing precipitation type of snow.
MARINE...
Diffuse area of higher pressure will allow winds speeds to gradually
decrease through the evening and overnight hours. Small Craft
Advisories will continue for outer Saginaw Bay down into Port
Sanilac as northwesterly flow backs a little more to the west north-
west and allows elevated wave heights to persist despite the
decrease in wind speeds. Otherwise, Small Craft Advisories will be
allowed to expire tonight. A weak pressure gradient will hold
through the weekend and will bring ligher winds leading into Monday.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....MR
DISCUSSION...CB
MARINE.......HI
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Hanford CA
212 PM PDT Fri Apr 16 2021
.SYNOPSIS...A warming trend will continue across the area through
the weekend with temperatures expected to be well above normal on
Sunday and Monday. A cooling trend will take place during the
middle of next week. Lingering afternoon and evening showers will
continue over the Sierra Nevada through Saturday.
&&
.DISCUSSION...An upper level shortwave dropping southward behind
an upper level low pressure center over UT has provided enough
instability this afternoon for some cumulus build-ups and even a
few showers over the higher elevations of the Sierra Nevada. The
remainder of our area is mostly sunny with temperatures generally
running a few degrees higher than Thursday at this time.
HRRR and SREF indicating the ridge centered off the western CONUS
coast building further inland on Saturday which will result in
slightly warmer temperatures on Saturday. There will still be
enough instability for a few afternoon showers over the Sierra
Nevada, mainly south of Kings Canyon. The building ridge will
produce a period of breezy northeast to east winds along the
Sierra crest Saturday morning through Sunday morning. The other
impact the ridge will have is that is will bring warmer
temperatures to our area on Sunday and Monday with daytime highs
expected to be well above seasonal normals. Probabilistic guidance
continues to indicate a 27% chance of Fresno reaching the 90 DEG
F mark on Monday.
The medium range models and ensemble members are in agreement
with the ridge breaking down on Tuesday as a upper low pressure
system drops out of the Gulf of AK into the Pac NW. This low is
progged to drop southeast over the Sierra Nevada range on
Wednesday and bring cooler temperatures to the area along with a
chance of mountain showers over the Sierra Nevada and increased
winds across the Kern County Mountains and Deserts.
Ensemble means are showing the ridge rebuilding inland into CA
next Thursday and Friday and bring warmer temepratures and dry
conditions to our area by the end of next week.
&&
.AVIATION...Areas of MVFR and local mountain obscuring IFR are
possible in clouds and showers along the high Sierra Nevada after
until 03Z Sat and again after 19Z Sat. Otherwise, VFR conditions
are forecast to prevail across the central CA interior over the
next 24 hours.
&&
.AIR QUALITY ISSUES...None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
public/aviation/fire wx...DS
idss/pio...Andersen
weather.gov/hanford
Area Forecast Discussion
National Weather Service Huntsville AL
848 PM CDT Fri Apr 16 2021
.NEAR TERM...(Tonight)
Issued at 848 PM CDT Fri Apr 16 2021
Under scattered mid level clouds and a blanket of higher altitude
clouds, mid evening temperatures were mainly in the mid/upper 50s
with light winds. 00Z soundings indicated a substantial dry layer
between 850-700mb over the region. This dry layer was helping to
evaporate rainfall preceding a weak system nearing from the west.
Precipitation echoes via local and regional radar covered an area
roughly from the Mid South, across much of Mississippi, and extending
across central Alabama. The closest rain far as measurable amounts
were from central Mississippi and westward.
Output from the shorter term CAMs, along with 18Z NAM/GFS indicated
the bulk of the showers should remain south of the region, closer to
Gulf where deeper moisture was present. Precipitation further to the
north was showing a trend of fading as it progressed eastward. The
295K region from the RAP indicated only weak upglide, which further
suggests that rain, when it begins in the overnight, should remain
on the light side. With clouds and more moisture, low temperatures
should not be chilly as last night, but should cool into the upper
40s to lower 50s. The on-going forecast has this well in hand. No big
changes are planned for the overnight.
.SHORT TERM...(Saturday through Sunday)
Issued at 1258 PM CDT Fri Apr 16 2021
This second chance of rain will occur in the morning, mainly tied
with the upper shortwave. However, the models have been dampening the
amplitude of this wave, and this has limited the southerly low level
component of flow to our south. Thus, keeping the main
convergence/moisture zone well to our south, while the northern
precip will be more tied to weakening QG forcing aloft. In either
case, only light QPF is indicated, with a dry afternoon Saturday
expected. Lower clouds could thin some, and possibly scatter out
during the afternoon hours. Clearing will be more likely Saturday
night per RH time sections. So high temperatures Saturday will
depend on any sunshine filtering through, and may need to lower a bit
in subsequent forecasts. Likewise, cloud trends Saturday night will
dictate how cool it will get. Right now, went slightly below
suggested blends in the 40-45 degree range. Sunday should be a fine
weather day with highs in the upper 60s for most. The only caveat is
the shortwave dropping southeast into the lower OH/TN valley late in
the day into the evening. There is a bit more moisture and QPF
associated with this in middle TN that could skirt southern TN and
far north AL. For now, will keep rain out but advise next shift to
watch closely.
.LONG TERM...(Sunday night through Thursday)
Issued at 1258 PM CDT Fri Apr 16 2021
Monday should bring another mild day in the upper 60s to lower 70s
with shortwave ridging moving east. Tuesday may even be warmer just
ahead of the next cold front. The models also bring several weak
small shortwaves through the southwest flow at 5H across the Gulf
states northeast through the Southeast U.S. This could bring mid
level clouds and possibly light rain Tuesday. For now, would like
better model consistency on this and will leave out. The front
arrives either Tuesday night or Wednesday (still model timing
discrepancy here). The latest runs are showing a bit more precip
chance with or just behind the front. Will again wait for more
consistency as this was a bone dry front yesterday. One thing is a
near certainty. More unseasonably cool weather behind this next front
with highs in the upper 50s to lower 60s Wednesday. Lows in the
middle to upper 30s are expected Thursday morning, so will have to
watch for frost potential, especially in southern TN and our
northeast TN valleys.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 644 PM CDT Fri Apr 16 2021
VFR weather should continue into the late night, before a weak system
approaching from the southern plains brings a chance of light rain
Sat morning. Most of the shower activity should remain south of the
Tennessee Valley. General lower level VFR minimums should continue,
but MVFR CIG/VIS reductions are possible in the heavier rain. The
precipitation should end from NW-SE in the late morning and early
afternoon as the system shifts more to the east. Light winds tonight
should become NW, increasing into the 5-10kt range in the afternoon.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...RSB
SHORT TERM...17
LONG TERM...17
AVIATION...RSB
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Lincoln IL
755 PM CDT Fri Apr 16 2021
.SYNOPSIS...
Issued at 749 PM CDT Fri Apr 16 2021
Occasional showers will affect central and southeast Illinois
overnight into Saturday, though areas near and north of I-74 are
most likely to remain dry. Overnight temperatures will be milder
than recent nights, though the cloudy skies will keep the daytime
highs on Saturday cooler than on Friday.
&&
.UPDATE...
Issued at 755 PM CDT Fri Apr 16 2021
Latest radar mosaic showing the leading edge of the showers
approaching the Mississippi River. Evening sounding from our
office shows a fairly dry air mass except for a pinch of moisture
around 7,000 feet, where the current cloud base is located. NAM
guidance suggests a fairly rapid moistening of the air from the
top down as the rain approaches, though the GFS is a bit slower in
that regard. 18Z run of the NAM nest is doing the best job at this
point with its precipitation depiction, and projects more of an
west-east pivot of the rain shield overnight to favor areas north
of I-74 mainly remaining dry. Forecast has been updated to make
some minor adjustments with the timing and placement of the higher
PoP`s tonight and Saturday morning.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 251 PM CDT Fri Apr 16 2021
An upper low evident on 19z/2pm water vapor imagery along the
Nebraska/Kansas border will track E/SE and weaken over the next 24
hours. As this feature approaches, clouds will be on the increase
this evening...followed by a few showers overnight into Saturday.
Latest models have all slowed precip onset by about 3-6 hours,
which seems reasonable based on regional soundings showing ample
dry air below 500mb. Based on latest HRRR output, have gone mainly
dry this evening...with low chance PoPs arriving along/southwest
of a Macomb to Effingham toward midnight. Showers will spread
further northeast overnight: however, due to the dry boundary
layer and the weakening upper forcing, very little rain will make
it to the I-74 corridor or northward. Have therefore focused
likely to categorical PoPs across the S/SW KILX CWA...with just
slight chance across the N/NE. The showers will linger through
Saturday morning, then will decrease in areal coverage as the day
progresses. Storm total rainfall will remain quite light...amounting
to one tenth of an inch or less.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 251 PM CDT Fri Apr 16 2021
A second short-wave trough currently over eastern Montana will
track into the region on Sunday...triggering scattered showers.
Given the timing of the wave during peak heating and the fact
that NAM MUCAPE values reach 300-400J/kg, have opted to include
slight chance thunder across the southern half of the CWA Sunday
afternoon. Once this feature passes, a warm/dry day will be on
tap for Monday with highs climbing into the lower to middle 60s.
After that, a strong cold front will sweep through the
Midwest...introducing sharply colder conditions by mid-week. As
noted by the last couple of model runs, latest suite suggests
boundary will be an anafront...with light to moderate precip
developing on the cold side. Given good agreement between the GFS
and ECMWF, have increased PoPs along/northwest of I-55 late
Monday night...then across the board on Tuesday. With temps
dropping into the middle to upper 30s behind the front, may see a
rain/snow mix along/north of a Macomb to Bloomington line late
Monday night into early Tuesday morning. The remainder of Tuesday
will be blustery and colder with occasional rain showers. Highs
will remain in the 40s north of the I-70 corridor, with wind-
chills in the 30s at times. Once the front passes, skies will
clear and air temperatures will plunge into the lower 30s...and
potentially lower if winds diminish sufficiently...Tuesday night.
Will need to keep an eye on both Tuesday night and Wednesday night
for potential frost/freeze conditions. After that, temperatures
will moderate back into the lower 60s by Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 610 PM CDT Fri Apr 16 2021
In general, VFR conditions will prevail the next 24 hours. Main
question will be around KSPI, where light rain showers are
expected to begin after 06Z and linger into Saturday morning. Some
potential for ceilings to slip below 3,000 feet in this area after
12Z. Otherwise, most ceilings overnight into Saturday morning will
average closer to 5,000 feet.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Memphis TN
837 PM CDT Fri Apr 16 2021
.DISCUSSION...
Skies are mostly cloudy across the Mid-South this evening with
temperatures in the mid to upper 50s. A few light rain showers are
moving across the region at this time. Additional showers are
expected to move through the Mid-South during the overnight hours
but should not amount to much rain. Will update the forecast to
remove any evening wording.
ARS
&&
.PREV DISCUSSION... /issued 345 PM CDT Fri Apr 16 2021/
DISCUSSION...
A cool and cloudy day across the Mid-South at this hour. Skies are
overcast across the region with light rain showers just off to
our west. The upper level pattern is dominated by a nor`easter off
the coast of Maine, with a large trough over the Central Plains.
A weak shortwave is currently translating through the Lower
Mississippi Valley, as seen from GOES east lower water vapor
imagery.
The aforementioned wave is expected to lift through the region
over the next couple of hours, with mainly scattered showers
developing across the forecast area. The large trough, currently
over Nebraska, is expected to push through the region late tonight
into tomorrow afternoon. This will bring the highest chance of
rain to the region. Nonetheless, QPF totals will remain light with
under a quarter of an inch expected. Rain will lift out of the
area by Saturday late morning, as the main trough pushes east of
the region.
Saturday will be cool again with highs in the low to mid 60s with
partly sunny skies by the afternoon hours. Sunday will see a bit
more sunshine and temperatures will climb into the mid to upper
60s accordingly. Another northern stream shortwave will translate
through the region late Sunday night through early Monday
morning. This will bring a decent chance of rain to northern
portions of the Mid- South through this period. Added a slight
chance of thunder to the forecast, as mid and upper level lapse
rates will steepen.
Dry and cool weather will persist on Monday and much of Tuesday,
as surface high pressure builds in across the Mid-South. Upper
level zonal flow will shift southwesterly late Tuesday, ahead of
an approaching trough. This trough will help push a cold front
through the region Tuesday night into Wednesday morning. POPs
aren`t overly impressive at this time, but may increase as we get
closer in time to that forecast period. Behind the front, cold
Canadian high pressure will build into the region. Preliminary MOS
temperatures suggest lows in the mid to upper 30 for both
Wednesday and Thursday mornings. This would bring a chance of
frost to much of the region, especially across northeast Arkansas,
the Missouri Bootheel, and northern portions of west Tennessee.
Will hold off on adding to the HWO, as confidence isn`t terribly
high at this point.
The pattern looks to remain progressive in the extended with
moderating temperatures.
AC3
$$
.AVIATION...
00Z TAFs
Scattered to numerous high-based rain showers over AR will
gradually lift east this evening. NAM and RAP soundings, as well
as HRRR and SREF CIG prob charts suggest rain coverage and
intensity may be insufficient to lower ceilings below FL020 fuel
alternate thresholds. Confidence is limited for even sub-FL030
ceilings at MEM and MKL toward 12Z, given deepening frontal depth
at that time. For the 00Z TAFs, have avoided significant changes,
but reflected the latest, more optimistic guidance.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$