Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/27/23
Area Forecast Discussion
National Weather Service Cleveland OH
938 PM EDT Wed Apr 26 2023
.SYNOPSIS...
High pressure builds into the region tonight before departing to
the northeast on Thursday. Low pressure develops over the lower
Mississippi Valley on Thursday, lifting northeast to the Ohio
Valley Friday before meandering across the Great Lakes Saturday
and Sunday. A trough of low pressure lingers across the Great
Lakes early next week.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
Diurnal cloud cover has dissipated this evening, leading to
clear skies across the region. Temperatures will continue to
drop over the next several hours into the low 30s and perhaps
upper 20s in some spots across far NE OH and inland NW PA.
Satellite imagery does reveal some high cloud cover moving east
into the southern portion of the area which could limit
radiational cooling.
Previous Discussion...
High pressure and upper-level ridging build in tonight. A still
cool atmosphere, along with favorable radiational cooling
conditions tonight will allow for temperatures to drop in the
30-35 degree range tonight into early tomorrow morning. This
will allow for widespread frost across the area, for which frost
advisory and freeze warnings are in effect for.
Temperatures on Thursday recover as high pressure departs to the
northeast, with warm air advection on the backside of the
departing high will bring temperatures back up into the low to
mid 60s. Lakeshore communities may stay a bit cooler due to the
development of a lakebreeze.
By Thursday night, the next low pressure system approaches from
the lower Mississippi Valley, with rain overspreading the area
from south to north. Most model guidance has rain encompassing
most of the area by very late Thursday night into early Friday
morning, though one outlier is the 18Z HRRR (which has
precipitation slow to overspread the area).
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Low pressure over the southern Ohio Valley continues to move
northeastward toward the lower Great Lakes to begin the short term
forecast period. Widespread rain showers are expected across the
entire area on Friday with a chance for isolated thunderstorms by
Friday afternoon given our placement in the warm sector and some
instability developing over the southern portion of the forecast
area. There may be a brief dry period across western zones overnight
Friday into Saturday morning as a dry slot looks to develop between
systems late this week.
Another round of mainly showers is expected on Saturday as a
deepening upper level trough and surface low pressure move eastward
from the Upper Midwest toward the lower Great Lakes region. This low
will swing a cold front across the area Sunday into Monday, more on
that in the long term portion of this discussion. Models are hinting
at a few hundred Joules of CAPE mainly across western areas of the
forecast region on Saturday afternoon. As such, have slight chance
to chance thunder along and west of the I-71 corridor for Saturday
afternoon.
Overall QPF amounts in the short term forecast period range between
0.50-0.75 inches with additional rainfall expected in the long term
portion of the forecast. Will need to monitor our usual river flood
suspects this weekend given the anticipated rainfall. High
temperatures will generally be in the low to mid 60s each day with
lows in the mid to upper 40s each night.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The long term will be characterized by a period of cooler and wet
weather. We`re stuck in a pattern of deep upper level troughing, a
stagnant upper level low, and multiple embedded shortwaves that move
across our forecast area every day/day and a half. We may finally
catch a break by Wednesday as high pressure builds into the forecast
area from the south and extends a ridge northward, though there
remains potential for lingering showers across NE OH/NW PA through
Wednesday evening.
The second low pressure mentioned in the short term portion of the
discussion will swing a cold front across the forecast area Sunday
night into Monday morning. This will cool temperatures down for the
majority of the long term period. Highs on Sunday will be near 60
degrees but will fall into the low 50s by Monday and Tuesday. As
ridging builds into the area by Wednesday, highs look to return near
60 degrees. Low temperatures each night of the long term period will
fall into the mid 30s to low 40s.
&&
.AVIATION /00Z Thursday THROUGH Monday/...
VFR across the TAF sites this evening with VFR to persist
through the TAF period. Winds will become light and variable
tonight, increasing out of the southeast, 5 to 10 knots, by
tomorrow afternoon. The exception will be at TOL/CLE/ERI where a
lake breeze will develop, resulting in northeast winds around 10
knots.
Outlook...Non-VFR is possible in rain Friday through Sunday.
Non-VFR may persist during the day Monday in rain showers.
&&
.MARINE...
Light and variable winds should persist over Lake Erie through
Thursday evening. Winds by Thursday night become northeasterly at 10-
15 knots. Low pressure will lift northeastward across the lake on
Friday night. Winds turn more southerly with the potential for
downsloping and winds in excess of 20 knots across nearshore waters
of the eastern basin of the lake Friday night. Behind the low, winds
take on a southerly to southwesterly direction and remain at 10-15
knots.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Freeze Warning from 2 AM to 8 AM EDT Thursday for OHZ003-006-
008>011-013-014-018>023-031>033-038.
Frost Advisory from 2 AM to 8 AM EDT Thursday for OHZ007-012-
017-027>030-036-037-047-089.
PA...Freeze Warning from 2 AM to 8 AM EDT Thursday for PAZ002-003.
Frost Advisory from 2 AM to 8 AM EDT Thursday for PAZ001.
MARINE...None.
&&
$$
SYNOPSIS...Saunders
NEAR TERM...Kahn/Saunders
SHORT TERM...Iverson
LONG TERM...Iverson
AVIATION...Kahn
MARINE...Iverson
Area Forecast Discussion
National Weather Service Corpus Christi TX
1038 PM CDT Wed Apr 26 2023
...New UPDATE...
.UPDATE...
Issued at 1036 PM CDT Wed Apr 26 2023
Cold front is draped across a line from approximately Marble Falls
to the Devil`s Sinkhole Natural Area. The front is moving a little
slower than anticipated. Have been leaning with HRRR with analysis
as it has the best representation of the activity currently
occurring around the Austin area. Based off of the 00Z run, activity
ahead and along of the front is forecast to arrive between 10-12Z.
We do remain in a marginal risk for severe weather, and the 00Z
sounding does reflect an unstable environment ahead of the
front...limiting factor is that the mid-levels are pretty dry (RH
values around 25%).
Current thoughts are that as this line of storm moves south
overnight, it`s going to hit pockets of sufficient moisture
convergence and instability and appear as a broken line of showers
and storms. While some storms could occur ahead of the main line,
shear vectors are generally parallel to the boundary, so the mode of
storms should remain primarily linear. The severe threat will likely
be isolated as it enters the northern tier counties, with mesoscale
boundaries playing a big role in where stronger to severe storms
will occur within this line. As discussed in the previous AFD, main
hazards continue to be the threat of damaging hail (>1") and
damaging winds (>60mph).
Since the front appears to be moving slower than initially expected,
this will give time for locations closer to the coast to undergo
some destabilization ahead of its arrival. SPC has the southern
Coastal Bend in a slight risk (level 2 of 5) and the Coastal
Plains/Victoria Crossroads in a marginal risk (level 1 of 5) for
Thursday morning.
Activity should push offshore around the early afternoon hours.
&&
.SHORT TERM...
(Tonight through Thursday night)
Issued at 131 PM CDT Wed Apr 26 2023
Key Messages:
- Strong to severe thunderstorms possible late tonight through
Saturday morning.
Cloud cover will increase tonight ahead of an approaching cold
front. Based on model guidance, it appears the front will arrive
sometime around 09Z, then move swiftly through South Texas,
pushing offshore between 18Z and 21Z. Ample moisture, convergence
along the frontal boundary, and moderate to high instability will
lead to the potential for strong to severe thunderstorms. With
CAPE values over 2400 J/kg and steep lapse rates, large hail is
likely going to be the greatest threat, especially along the coast
and over the Victoria Crossroads. DCAPE values are expected to be
near 1200 J/kg, so strong winds will be expected across the
entire area. The Storm Prediction Center (SPC) has included our
northern areas in a Marginal Risk of Severe weather with a Slight
Risk of Severe Weather expected across the southeastern Coastal
Plains Saturday--mainly Saturday morning.
Behind the front, high pressure will build in with slightly cooler
and much drier air filtering in. Cloud cover will slowly recede
as the front passes, leaving us with a mostly clear night.
&&
.LONG TERM...
(Friday through next Tuesday)
Issued at 131 PM CDT Wed Apr 26 2023
Key Messages:
- Cold front will bring scattered to numerous showers and
thunderstorms Friday night through Saturday.
- Marginal to slight risk for severe thunderstorms Friday night.
Another in a series of disturbances is progged to move across S TX
Friday night/Saturday, bringing a cold front through the area late
Friday night into Saturday morning. There remains some uncertainty
with timing of the front and corresponding precip as models continue
to flip flop. Latest runs of the ECMWF, GFS, Canadian are in
somewhat better agreement with the front across the coastal waters
by 12Z Saturday morning.
Ahead of the cold front, a pool of deeper moisture with PWATs up to
1.8 inches will combine with an unstable airmass, increasing
diffluence aloft, and very strong low level convergence to produce
showers and thunderstorms with some storms potentially becoming
strong to severe. Hail and wind would be the primary threats. Can
not rule out localized flooding, however, the front is expected to
push through S TX fairly quickly keeping rainfall amounts
The Storms Prediction Center has the eastern portions of S TX in a
marginal risk and the western portions in a slight risk for Friday,
mainly Friday night. The severe risk could shift east by early
Saturday morning. The main fly in the ointment will be the cap and
increasing CIN values Friday night that could inhibit convective
development, but the cap is progged to erode per forecast soundings.
Drier and cooler conditions are expected Saturday as high pressure
builds across S TX. Latest model runs also show stronger northerly
winds Saturday, which, combined with a drier airmass, may lead to
elevated fire weather conditions Saturday afternoon.
The environment begins to modify Sunday with onshore flow returning
Sunday afternoon or evening. This will lead to a gradual warming
trend and increasing humidity through the first half of next week,
but rain chances remain out of the forecast due to dry mid/upper
levels and strong cap.
&&
.AVIATION...
(00Z TAFS)
Issued at 639 PM CDT Wed Apr 26 2023
Not much change from 18Z forecast. VFR/MVFR CIGs will continue
across south TX, with IFR conditions developing around 10Z around
the arrival of the cold front. Showers and thunderstorms, a few
strong to severe, are expected during the early morning hours
Thursday, with conditions improving to VFR for all sites Thursday
afternoon. VCT terminal may be a couple hours slower to improve
compared to the other sites.
&&
.MARINE...
Issued at 131 PM CDT Wed Apr 26 2023
Weak onshore flow will shift to the northeast behind a cold front
early Thursday morning. Scattered showers and thunderstorms are
expected late Friday night into Thursday as the cold front moves
across the waters. Strong to severe storms are possible with gusty
winds and large hail. A weak to moderate onshore flow will
persist Friday and Friday night. An approaching upper level
disturbance and corresponding cold front will contribute to
scattered showers and thunderstorms Friday night through Saturday.
Moderate to strong offshore flow is expected Saturday after
frontal passage. Cooler and drier conditions are expected Saturday
night and Sunday. A weak to moderate onshore flow will return by
early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 70 83 66 84 / 30 40 0 0
Victoria 68 81 59 84 / 30 50 0 0
Laredo 70 85 67 94 / 30 40 0 0
Alice 69 84 64 89 / 30 40 10 0
Rockport 71 81 69 81 / 30 40 0 0
Cotulla 68 88 65 95 / 40 30 0 0
Kingsville 70 84 65 87 / 30 40 0 0
Navy Corpus 72 80 70 80 / 30 30 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...LS
LONG TERM....TE
AVIATION...HA
Area Forecast Discussion
National Weather Service Cheyenne WY
529 PM MDT Wed Apr 26 2023
.SHORT TERM...(This evening through Thursday Night)
Issued at 319 PM MDT Wed Apr 26 2023
Latest GOES WV imagery shows a shortwave moving across SD with
increased moisture extending to the southwest towards our area.
This has led to marginal instability across the area today with
widely scattered light rain showers. These showers will continue
throughout the remainder of the afternoon. Tonight, 700mb flow
across Carbon Co will increase to near 35 kt behind the shortwave
axis. This will lead to gusty winds near the Arlington/Elk
Mountain areas along I- 80. In-house guidance continues to suggest
elevated winds gusting near 50 mph after midnight, but will
continue to monitor obs trends overnight.
Looking ahead to tomorrow, the main forecast concern arrives in the
afternoon and evening as a 125kt upper level jet and associated cold
front dive south across WY. Ahead of the front, latest RAP guidance
shows 700-500mb lapse rates increasing over 8 C/km with 200-400 J/kg
of MLCAPE. Forecast soundings show fairly dry low-levels with sfc
dewpoints around 30F and LCLs above the freezing level. This will
lead to showers, possibly a few thunderstorms with gusty winds in
the vicinity. Additional forcing will arrive with the frontal
passage mid-to-late Thursday afternoon, but so too will be the
arrival of colder air.
West of the Laramie Range, arrival of heavier precipitation rates
will quickly transition ptype over to snow from Rawlins to Laramie.
Latest hi-res guidance brings the front and associated precipitation
into the I-80 corridor around 5-6 PM MDT Thursday. Heaviest
accumulations are expected in the mountains with 1-2 inches for
areas near Laramie and Rawlins. SREF plumes do show a few members in
the 3-5 inches range for Laramie as strong frontal forcing and
initially northwest winds could support locally higher snowfall
totals on the east side of town into the South Laramie Range.
Decided to issue Winter Weather Advisory for the Snowy Range and
North Snowy Range Foothills including the Arlington and Elk Mountain
areas along I-80. Northerly winds will support additional upslope
flow and lingering snow showers through the night that could make
travel hazardous at times. Additionally, strong winds with the
frontal passage could further reduce visibility in blowing snow.
Farther east along the I-25 corridor into the NE Panhandle, higher
uncertainty exists with the timing of snowfall transition. Areas
along the Cheyenne and Pine Ridges will see an earlier transition
Thursday evening with accumulation up to an inch. Rain/snow mix will
continue to spread eastward into the NE Panhandle overnight as
colder air continues to move into the CWA. Strong northerly winds
behind the front gusting up to 55 mph are also possible. As quickly
as this system arrived, heaviest snowfall should end by daybreak
Friday morning with lingering snow showers continuing through the
rest of the morning.
.LONG TERM...(Friday through Tuesday)
Issued at 330 AM MDT Wed Apr 26 2023
No major changes with this forecast package. An upper-level ridge
over the Pacific Northwest slowly slides towards the area as the
late week system moves out of the region. Pleasant and mostly dry
weather expected for the long term.
Behind the late week system a 250 mb ridge begins to move in from
the Pacific Northwest as an upper-level low develops Friday evening
over southern Ontario. This upper-level low strengthens and sandwiches
the 250 mb ridge between it and another low off the coast of the
Pacific Northwest. A similar evolution is expected at both 500 mb
and 700 mb, with the ECMWF and GFS being in good agreement about
the development and eastward progression. The 250 mb ridge axis over
eastern Oregon, eastern Washington, and points south slowly progresses
easterly Friday afternoon through Monday. By Monday afternoon the
ridge axis will finally have traversed across Idaho and will be
positioned from central Montana southward through western Wyoming
with two well-developed lows on either side of the ridge. Quiet
weather is expected across the CWA as the upper-level ridge slowly
moves eastward. Temperatures are expected to be in the mid-60s to
low-70s across the CWA with minimal precipitation chances.
Warm temperatures and pleasant weather continues through Wednesday
afternoon when precipitation chances increase. By this time, the
upper-level ridge axis will be just east of the CWA oriented
northwest to southeast across eastern Montana, the western South
Dakota, and western Nebraska. The ECMWF starts to break down the
Omega Block by the end of the long term period while the GFS keeps
the Omega Block in the upper-levels around a few days longer. Trends
will need to monitored to determine exactly when this blocking
pattern begins to breakdown and more progressive flow begins again.
Meanwhile, enjoy the warm temperatures and pleasant weather expected
during the long term.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 522 PM MDT Wed Apr 26 2023
Wyoming TAFS...Rather benign northwest flow aloft will prevail
tonight with scattered to broken clouds from 6000 to 10000 feet
AGL. A strong cold front will move north to south across the
terminals on Thursday producing isolated to scattered showers and
ceilings around 8000 feet AGL. Sufficient pressure gradients will
produce wind gusts to 35 knots after 13Z Thursday.
Nebraska TAFS...Relatively benign northwest flow aloft will
prevail tonight with scattered clouds from 5000 to 10000 feet AGL.
A strong cold front will move north to south across the terminals
on Thursday producing scattered to numerous showers reducing
visibilities near 4 miles along with ceilings from 5000 to 6000
feet AGL. Decent pressure gradients will produce wind gusts to
35 knots Thursday afternoon after the cold frontal passage.
&&
.FIRE WEATHER...
Issued at 319 PM MDT Wed Apr 26 2023
Precipitation associated with a low pressure system over the
southern Rockies will taper off this morning. Skies will become
partly cloudy this afternoon with milder temperatures. A potent
fast-moving low pressure system and cold front will dive south
through the region Thursday afternoon and evening, producing
numerous rain and snow showers as well as some thunderstorms.
Strong and gusty west to northwest winds will accompany the
frontal passage. Moderate to locally heavy snow accumulations are
expected above 8500 feet. Colder temperatures Friday will moderate
to above normal this weekend.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory from 5 PM Thursday to 6 AM MDT Friday
for WYZ110-114.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...AM
AVIATION...RUBIN
FIRE WEATHER...MJ
Area Forecast Discussion
National Weather Service Peachtree City GA
832 PM EDT Wed Apr 26 2023
...New 00Z Aviation Discussion...
.SHORT TERM...
(This evening through Thursday)
Issued at 332 PM EDT Wed Apr 26 2023
Scattered showers are ongoing this afternoon across north Georgia as
vestiges of a weak upper wave pushing eastward into the Carolinas.
These north Georgia showers will continue to diminish over the next
couple of hours. Farther south, SBCAPE values have reached over 1000
J/kg across Middle Georgia, so the potential for an isolated shower
or thunderstorm remains in place through the early evening. Coverage
is expected to remain isolated, and any convection will diminish
through the evening.
While showers initially are expected to taper this evening, another
weak upper wave will assist in some degree of increase in showers
across far north Georgia early Thursday morning. The coverage,
especially how far south these showers extend, is uncertain with
most hi-res guidance keeping this activity largely north of metro
ATL, though the HRRR presents more widespread showers as far south
as metro ATL. At this point, kept the highest PoPs through tomorrow
AM across far north Georgia, tapered to isolated coverage down to
the I-20 corridor.
Regardless, the primary forecast focus will be on the more potent
system that will affect the area tomorrow afternoon into tomorrow
night. A stronger shortwave will push from the Southern Plains
toward the mid-Mississippi Valley during the day tomorrow with a weak
attendant surface low forming across the ArkLaMiss region and
lifting northeast into tomorrow night. While this traditionally
would support an increased threat for widespread thunderstorms
locally, there do remain some uncertainties regarding the degree of
strong/severe potential.
The chief complicating factor will be the degree to which coastal
convection limits moisture return and convective development across
our CWA. An embedded southern shortwave in the Lower Mississippi
Valley looks to initiate widespread convection which will be ongoing
across the Gulf Coast region of Louisiana/Mississippi tomorrow
morning. This activity then pushes eastward as an MCS through the
afternoon. This would likely serve to shunt the higher severe risk
farther south of most of our CWA, and the current Day 2 SPC
Convective Outlook supports this notion as the Slight Risk is
limited to our far southern tier. Even so, more widespread showers
and thunderstorms are likely to develop along the outflow from this
activity tomorrow afternoon and push eastward across our area, so
PoPs increase markedly through the afternoon into the evening with
the threat for locally heavy rainfall and at least isolated severe
remaining a possibility.
RW
&&
.LONG TERM...
(Friday morning through next Tuesday)
Issued at 332 PM EDT Wed Apr 26 2023
Main forecast concerns in the long term period are will there be any
strong/severe convection and when will the rain end (answer: Sunday).
Active southern stream of westerlies to persist across the region
through at least Sunday before large/deep upper vortex pushes south
over the Great Lakes and finally picks up lagging, positively-tilted
wave in the southern branch over TX. A dry/cool pattern with below-
normal temps follows with very slowly progressing long-wave trough
over the eastern CONUS thru next Wednesday.
Filling in some of the important details, as the first main wave on
ejects out of southern stream over SE states Thursday night, SW flow
still in place on Friday often favors the development of dense fog
as long as low level moisture does not get swept out. On Saturday
and Sunday, some indication in model guidance that another MCS may
develop to our south over the northern Gulf which would inhibit the
development of strong/severe storms. If MCS does not develop in that
area, environment should be favorable for severe storms both
Saturday, even though coverage of convection will not be fairly low.
Sunday may be more active, but this time track of upper wave and sfc
low and thus favorable severe storm environment SE of those
features, will be south of our area. Also seeing wide variation of
timing of final wave kicking out within global model ensemble
members. Some push it on early Sunday while others delaying until
Monday. Will continue to watch these periods closely.
While uncertainty on strong/severe storm likelihood and timing is
high, above average certainty that high rainfall rates will be low
enough to preclude flooding or flash flooding. If track of storms
moves back further north, this could change. SNELSON
&&
.AVIATION...
(00Z TAFS)
Issued at 810 PM EDT Wed Apr 26 2023
Challenging TAF forecast given tremendous differences in timing
and even presence of TSRA at ATL sites within models for Thursday.
Metro sites are currently low MVFR and expected to go IFR by 06Z
through early morning. Should rise again to low MVFR tomorrow, but
won`t rule out staying IFR for a longer period. Some SHRA expected
during afternoon, then line of storms may be far enough north to
move through ATL sites by 20-22Z. Uncertainty around where these
will be though, and possible that they are further south and
impacts at TAF sites are minimal. Winds will be E to SE, 6-12 kts
through period.
//ATL Confidence...00Z Update...
Medium confidence timing of TSRA, medium-high all others.
Lusk
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 51 72 60 78 / 20 60 70 60
Atlanta 54 72 61 79 / 20 80 70 50
Blairsville 47 63 54 73 / 30 60 70 60
Cartersville 51 71 58 78 / 20 80 70 50
Columbus 58 80 63 82 / 20 80 70 50
Gainesville 51 67 59 76 / 20 70 70 60
Macon 57 79 62 81 / 20 80 70 60
Rome 51 70 58 79 / 30 80 70 40
Peachtree City 53 75 59 80 / 20 80 70 50
Vidalia 60 82 64 81 / 20 60 60 70
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...RW
LONG TERM....SNELSON
AVIATION...Lusk
Area Forecast Discussion
National Weather Service Goodland KS
613 PM MDT Wed Apr 26 2023
.UPDATE...
Issued at 613 PM MDT Wed Apr 26 2023
Based on the latest HRRR/NAM12 guidance, have begun to trend in
patchy/areas of fog from 06z Thursday through about 14z.
Expecting surface ridge to transition across the cwa overnight.
Looking for skies to clear, and with winds light/variable and
where rain has fallen, expecting fog. The focus is for the
following counties: in Colorado, mainly eastern portions of
Cheyenne. In Kansas, Sherman, Thomas, Wallace, Logan, southern
Gove, Greeley and Wichita. With skies expected to clear and light
winds, some areas receiving fog could see temps at or just below
freezing. Some localized freezing fog is possible that could
impact some elevated surfaces. But this is highly dependent on
skies clearing allowing for temps to drop. Will be monitoring and
update as needed.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 220 PM MDT Wed Apr 26 2023
Through Tonight: An upper level low, presently centered invof
Clayton, NM, will progress eastward across the TX Panhandle (this
aft/eve) into central OK (tonight). Ongoing rain and low overcast
(south of I-70 in northwest KS at 18Z) will continue to recede
southward this afternoon, ending in Greeley/Wichita counties
around or shortly before sunset this evening (~00Z) -- with an
overall clearing trend this evening and tonight. Decreasing cloud
cover, light winds, and moisture from recent rainfall may foster
the development of dense fog across portions of the area
overnight.. mainly along/south of I-70 (where more rainfall was
observed) in the 08-14Z time frame.
Synoptic Overview (Thu-Fri night): Shortwave energy presently
moving ashore British Columbia is progged to track SE-SSE into
Montana (tonight) then due S toward the 4-Corners (Thu-Thu
night).. on the eastern periphery of an amplifying upper level
ridge on the Pacific Coast. An associated cyclone will develop in
the lee of the southern Rockies /eastern NM, TX Panhandle/ on
Thu.. progressing SSE into central/southern TX Thu night and Fri.
Thu-Thu evening: Modest (~1025-1028 mb) high pressure --
emanating from widespread precipitation /evaporative cooling/ in
the lee of the northern Rockies (Thu) and reinforced by subsidence
/height rises/ in the wake of shortwave energy progressing
southward from the northern Rockies to the 4-Corners -- will surge
southward through the Tri-State area Thu eve/night.. the leading
edge of which will manifest as a northerly wind shift /effective
cold frontal passage/. High resolution guidance such as the HRRR
and NAM NEST suggest that scattered convection will accompany and
follow the frontal passage Thu evening (00-06Z Fri) -- presumably
forced by low-level convergence, a fleeting period of SFC-H85
frontogenesis, and synoptic ascent (to some extent) in the form of
a left /thermally indirect/ jet exit and broad cyclonic shear
vorticity -- in a thermodynamic environment characterized by
marginal surface-based instability (~250-500 J/kg MLCAPE in
advance of the front) and modest elevated instability (~500-1000
J/kg MUCAPE behind the front) and a kinematic environment
characterized by 30-45 knots of effective deep layer shear -- i.e.
an environment somewhat supportive of convective organization
(multicellular/transient supercellular). Furthermore, simulated
reflectivity and echo top forecasts via the HRRR indicate a
potential for modestly deep updrafts (20-30 KFT) along/north of
I-70 Thu evening. With the above in mind, an isolated severe storm
capable of producing an instance of severe wind (surface-based
convection invof the front in northeast CO prior to sunset).. or
marginally severe hail (elevated convection behind the front
between 01-06Z).. cannot be ruled out.. though confidence is low
with regard to whether or not convection of sufficient
depth/organization will materialize. Regardless, numerous post-
frontal /elevated/ showers (and a few storms) appear likely Thu
eve into Thu night.
Fri-Fri night: Breezy to strong N winds are anticipated in the
wake of the effective cold frontal passage late Thu night through
Fri morning -- mainly in eastern CO and adjacent KS/NE border
areas. GFS forecast soundings suggest a shallow (~2500 ft AGL)
post-frontal mixed layer.. with 30-40 knot flow therein.. mainly
between 06-18Z Fri. Limiting factors (for strong wind) include:
poor diurnal timing w/regard to FROPA, relatively weak low-level
cold advection, and considerable cloud cover. With this in mind,
HWW criteria is not anticipated.
.LONG TERM...(Saturday through Wednesday)
Issued at 140 PM MDT Wed Apr 26 2023
As we start the weekend an upper level low is expected to move
over the Red River area and Central Texas while high pressure
aloft sits over the far Western CONUS. This will place the area
under north to northwest flow aloft. The low is expected to
continue southeast into the Gulf of Mexico as a broad upper low
sits over the Great Lakes on Sunday. On Monday we see an omega
pattern settle over the CONUS as another upper low moves over the
Pacific Northwest as the ridges crosses the Rockies. Through early
next week the ridge is expected to continue getting pushed east
and over the High Plains by Wednesday.
With the ridge being dominant over the area through the
extended, precipitation chances are not looking too good for the
area at this time. There is potential for diurnal showers/storms
during the afternoon to early evening hours Tuesday and Wednesday;
however, there isn`t expected to be much support for severe weather.
Temperatures throughout the long term seem to be pleasant with highs
in the mid 60s to lower 70s Saturday through Monday and increasing
to the lower 80s by Wednesday. Overnight lows are currently forecast
to be in the mid to upper 30s through Monday night. Overnight
temperatures look to also increase at the end of the period with
lows in the 40s to lower 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 541 PM MDT Wed Apr 26 2023
VFR conditions to start with at both terminals this evening with
clouds lifting/clearing. Light and variable winds will transition to
more of a southwesterly component at 10-15 knots overnight,
beginning around 05Z. At GLD, we`re monitoring potential for
development of some patchy fog overnight into the early morning
hours, between around 09-12Z resulting in reductions to visibility
down to MVFR conditions. Will update with next TAF issuance as
necessary. Otherwise, VFR conditions.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JN
SHORT TERM...Vincent
LONG TERM...KMK
AVIATION...JN/CC
Area Forecast Discussion
National Weather Service Green Bay WI
1001 PM CDT Wed Apr 26 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Thursday
Issued at 322 PM CDT Wed Apr 26 2023
Synopsis: The latest RAP analysis and satellite imagery show high
pressure centered across the region early this afternoon. This
surface high will shift east tonight as a potent shortwave pushes
a warm front across the northern Mississippi Valley tonight and
Wisconsin on Thursday.
Sky/Precip: Thermal troughing remains more pronounced over
eastern WI early this afternoon, and combined with steep low
level lapse rates, contributed to a scattered to broken
convective cloud field. These clouds will likely dissipate later
this afternoon or this evening as warmer low level air surges in
from the west.
Strong warm advection will occur tonight thanks to a 50+ kt low
level jet. This will lead to showers moving across the region,
generally after midnight and north and west of the Fox Valley.
Slowed the arrival down by an hour or two. Despite the presence
of decent forcing and steep mid- level lapse rates, there is
little to no instability on forecast soundings. Therefore, left
thunder out of the forecast.
The showers will diminish on Thursday morning as the low level
jet weakens and lifts off to the northeast. After a relative lull
that may lead to partial clearing over central to northeast WI,
models show showers redeveloping west of the region at first
before spreading into north-central WI late in the afternoon.
Temps: Warmer temps are expected over the next 24 hours thanks to
strengthening southerly winds. Readings will fall off little
tonight and then warm into the mid 50s to mid 60s on Thursday.
.LONG TERM...Thursday Night Through Wednesday
Issued at 322 PM CDT Wed Apr 26 2023
Minimal changes made to the forecast from the past couple
forecast cycles.
Temperatures will still be near normal on Friday ahead of the
approaching cold front, reaching the upper 50s to middle 60s
during the afternoon. A cold front will come through during the
late afternoon and evening Friday bringing the rain with it. Snow
showers are also possible across far northern WI (as will be the
case most days in the long term, especially at night).
The upper trough will develop into a closed low over the Great
Lakes this weekend, keeping cool, cyclonic flow across the state.
Increased PoPs Saturday and Sunday afternoon as diurnally driven
showers will be most likely during this time. Cooler air will
get wrapped into this which will keep temperatures below normal.
Precipitation will not be constant, but the chance will exist
everyday through at least Monday. Timing will depend on individual
shortwaves and diurnal effects, but overall expecting precip
through the period be to below normal. Snow or a rain/snow mix is
possible across the Northwoods, otherwise ptypes will be
predominately rain.
Models are in decent agreement this far out showing high pressure
building into the region on Tuesday into Wednesday, which would
lead to at least a day or two of dry weather with more sunshine.
Return flow on the back side of the high would give temps a boost
on Wednesday.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 956 PM CDT Wed Apr 26 2023
No significant change to the aviation forecast with the 06Z TAF
issuance. A mid-level shortwave combined with strengthening
isentropic lift near the nose of a LLJ will bring an area of
showers east across mainly the northern part of the area tonight
into tomorrow morning. Cloud bases are expected to remain high
enough to maintain VFR conditions. LLWS will spread SE across the
area late tonight into Thursday morning. Deepening mixing on
Thursday will result in gusty surface winds developing in the wake
of the precip band.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....MPC
LONG TERM......KLJ
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Indianapolis IN
937 PM EDT Wed Apr 26 2023
.Forecast Update...
Issued at 937 PM EDT Wed Apr 26 2023
- FROST ADVISORY mainly along and north of I-70
- Mostly Clear and Cold Overnight
Surface analysis late this evening shows a large area of high
pressure stretching from Quebec across the Great Lakes to IA and NE
MO. This large dry high pressure system was continuing to keep a
cool and dry NE flow across Central Indiana. An upper low was found
over the TX panhandle. This feature was spreading high clouds into
the middle Mississippi valley, while slowly spreading eastward into
the Ohio Valley. Strong convection was found over Central TX within
the warm sector of that deep low pressure system. Dew points across
Central Indiana were quite dry, in the upper 20s to near 30. GOES16
shows the invasion of some high clouds from the southwest.
Overnight, the surface high is expected to continue to nudge
eastward, but the cool and dry lower level flow is expected to
persist. Forecast soundings show a dry column through the night.
Thus with light winds and only some high clouds along with dry dew
points, good radiational cooling conditions will be in place. Some
locales should fall to the middle and lower 30s as suggested by the
RAP and HRRR. Thus have expanded the frost advisory to those points
a bit farther south. Otherwise, the ongoing forecast appears in good
shape.
&&
.Short Term...(This evening through Thursday)
Issued at 304 PM EDT Wed Apr 26 2023
Quiet, cool weather continues through much of the short term as a
surface high moves north of the area tonight. Winds will start out
from the NNE and become more easterly overnight as that high moves
eastward. Lows tonight will again be in the 30s and 40s. The coldest
temperatures will be to the north which will also see the most clear
skies tonight so have gone ahead with a frost advisory across the
far north.
The next system to impact the area will be a low pressure system
moving in from the Southern Plains and ArkLaTex regions. Ahead of
this system, cloud coverage will be increasing from the south with
clouds becoming more widespread by the end of the day tomorrow. The
latest CAMs have rain moving in from the south starting tomorrow
afternoon, which may reach as far north as the I-70 corridor by 8
PM and continue to push further north through the beginning of the
long term period. Highs tomorrow will be a little bit warmer,
reaching up to the mid 60s.
&&
.Long Term...(Thursday night through Wednesday)
Issued at 304 PM EDT Wed Apr 26 2023
* Below normal temperatures persist through the long term period.
* Multiple opportunities for showers through early next week.
The significant mid-April taste of late Spring or even early Summer
weather will unfortunately remain a distant memory for the long term
period, as a highly amplified and very slowly progressive pattern
persists throughout the latter portion of this week into next.
Synoptically speaking, broad upper level troughing over the central
and eastern CONUS will steadily consolidate and intensify into an
anomalously deep closed upper level low centered over the Great
Lakes and slowly pushing into the northeastern states through the
period. Another closed low will slowly move onshore on the West
Coast, with initially high-amplitude but steadily weakening upper
level ridging over the Intermountain West into the Rockies during
the period. Level of guidance agreement on these features is pretty
good overall, especially for such an amplified pattern.
At the surface, this large upper level low will result in showers
late in the week associated with a modest surface low moving into
the lower Ohio Valley and pivoting into the Great Lakes Thursday
evening into the early part of the weekend, with the strengthening
upper level low itself and perhaps one or more secondary frontal
boundaries associated with the aforementioned surface cyclone
pivoting into the region and producing more showers at times through
the weekend into early next week. The heaviest precipitation (around
a half inch) during the period appears likely to be Thursday night,
with much lighter amounts anticipated with the subsequent showers.
Only minor updates were needed to the near term forecast, mainly
lowering the cloud coverage slightly as it will be mostly sunny
today. Today will be mild with highs in the upper 50s to mid 60s
with light northeasterly winds.
Convective indices suggest an isolated mostly embedded thunder
threat at times, primarily Thursday night into the early portion of
the weekend, but no severe threat is expected, primarily due to
minimal instability.
Temperature-wise, below normal temperatures are expected to persist
through the long term period and beyond, much to the chagrin of
those, present company included, who enjoyed the recent warmup and
are anticipating pleasant late spring conditions. During this Update...
Issued atforecast period, the coolest temperatures (10F or more
below normal) are likely late in the weekend into early next week,
as 850mb temps drop below 0C. Frost/freeze concerns will have to
be monitored during this time frame, but this will depend heavily
on cloud cover and overnight wind conditions, which very well may
prevent these issues from materializing.
&&
.Aviation...(00Z TAF Issuance)
Issued at 626 PM EDT Wed Apr 26 2023
Impacts:
* VFR conditions prevailing through Thursday afternoon
* VFR conditions deteriorating to MVFR after 00Z Friday
Discussion:
VFR conditions will prevail across central Indiana through the
period. Surface high pressure over the Great Lakes will depart to
the east through Thursday afternoon. This will result in dry weather
with light winds through Thursday afternoon, ultimately, VFR.
High clouds will increase in coverage by the end of the period ahead
of a low pressure system creeps closer to the region. Forecast
soundings continue to trend toward a saturated column after 00Z as
low pressure arrives in the Ohio Valley and moves along the Ohio
River on Thursday Night. MVFR conditions will be expected at that
time.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 2 AM to 8 AM EDT Thursday for INZ021-028>031-
035>049-054>057.
&&
$$
Update...Puma
Short Term...KH
Long Term...Nield
Aviation...Puma
Area Forecast Discussion
National Weather Service North Platte NE
651 PM CDT Wed Apr 26 2023
...Aviation Update...
.SYNOPSIS...
Issued at 224 PM CDT Wed Apr 26 2023
Key Messages:
- After quiet and dry conditions today, a cold front will sweep
across the area on Thursday bringing a threat for showers and
thunderstorms in the evening. However, the severe threat remains low
at this time.
- North-northwest winds strengthen in the front`s wake on Friday,
with wind gusts of 40 to 50 miles per hour Friday afternoon.
- Blustery conditions persist Saturday with northwest winds
gusting to near 45 mph.
- Warming temperatures and dry conditions return this weekend into
next week.
Recent GOES-16 WV and RAP 500-analysis showed an upper-level low
situated across the Gulf of Alaska. Further southeast of this
feature, an upper-level low was centered across northeastern New
Mexico into the Texas Panhandle with a trough extending
southwestward across Arizona and northeastward across the Southern
Plains. A broad upper-level trough was evident across western
Quebec with a shortwave trough further northwest, tracking across
Saskatchewan into Manitoba. At the surface, low pressure was noted
across central Texas with an associated warm front tracking
northward across central and northern Texas and a cold front
tracking southeastward across the Upper Rio Grande into west and
south Texas. A surface trough of low pressure was apparent across
eastern Saskatchewan with a warm front extending south across much
of the High Plains into portions of the Panhandle and western
Nebraska. As of 2PM CT, temperatures ranged from 59 degrees at
Ogallala to 65 degrees in Valentine and Broken Bow.
&&
.SHORT TERM...(This evening through Friday)
Issued at 224 PM CDT Wed Apr 26 2023
Tonight...The aforementioned surface warm front will sweep across
the area into this evening with strengthening southwesterly low-
level flow behind it. Increased warm air advection (WAA) will
continue into tonight leading to mild low temperatures in the mid
30s to mid 40s across the area. Southwesterly winds become breezy
behind the frontal passage across portions of western and north
central Nebraska gusting up to 25 mph.
Thursday and Thursday Night...Strong WAA persists resulting in a
return to above normal temperatures on Thursday with highs in the
70s. A developing surface low will push southward out of Canada,
dragging a cold front along with it, reaching the area by Thursday
afternoon. Strong frontogenetical forcing will aid in the
development of scattered to widespread showers and thunderstorms to
western and north central Nebraska. Given the limited moisture, the
overall severe threat does appear low at this time. However, weak
instability (long, skinny SBCAPE ~300 J/kg) and steep lapse-rates
(approaching 9 C/km) develop across the area ahead of the cold
front. Recent forecast soundings show an inverted-v profile
suggesting that these showers and thunderstorms will be high-based.
The dry, deeply mixed boundary layer and modest DCAPE values
(~700 J/kg) will accelerate the downdraft which may result in
gusty downdraft winds any updrafts that can sustain themselves.
Forcing and instability weaken as the front continues to push
towards the southeast into the late evening on Thursday. The bulk
of any thunderstorm activity should diminish around 8 PM CT with
scattered to widespread rain showers continuing overnight into
early Friday afternoon. Total QPF amounts of 0.10" to 0.45" is
anticipated with this system though locally higher amounts are
possible within thunderstorms. Pressure rises and increased cold
air advection (CAA) will result in strengthening northwest winds
with gusts of 30 to 40 mph expected towards sunrise with even
stronger winds anticipated on Friday. Overnight lows will be near
or just below normal for the end of April in the low to mid 30s
across the Panhandle into the western Sandhills to the low 40s
across far north central Nebraska.
Friday...With Friday morning temperatures falling at or just below
freezing across the Panhandle into the northwestern Sandhills, a
brief period of rain/snow mix is possible in the early morning
hours. No snow accumulation is anticipated resulting in impacts
being minimal at best. Rain showers continue across portions of
western and north central Nebraska through early Friday afternoon.
North-northwesterly flow will strengthen on the backside of the
departing surface low resulting in strong winds on Friday.
Widespread gusts of 40 to 50 mph are expected during the day.
Daytime highs fall back into the 50s across the area which is 10
to 15 degrees below the climatological normal for the end of
April. Fortunately, warming temperatures return going into the
weekend and long time period.
.LONG TERM...(Friday night through Wednesday)
Issued at 224 PM CDT Wed Apr 26 2023
An upper-level low will deepen across Manitoba/Saskatchewan,
dropping south into the Great Lakes region on Saturday. An
associated surface low will drag a cold front along with it,
sweeping across western and north central Nebraska Saturday. This
system will result in continued gusty northwest winds on Saturday
and Sunday, though not quite on the same magnitude as of Friday.
Gusts of of 35 to near 45 mph will be common across western and
north central Nebraska on Saturday with some relief on Sunday,
though winds will remain gusty with gusts or 25 to 35 mph
expected. In terms of temperatures, highs will remain generally in
the 60s with only a few degree difference on Sunday in the wake
of the cold front. Surface high pressure will push southward across
the Plains behind the frontal passage on Sunday and continue
through the middle of next week.
Upper-level ridging will push eastward out of the Rockies into
the Plains on Tuesday bringing a return to southerly low-level
flow back into the region. This will aid in strong WAA
encompassing the area with high temperatures climbing into the
near or above the climatological normal for the start of May.
Limited surface moisture will also result in persistent dry
conditions through the middle of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 647 PM CDT Wed Apr 26 2023
VFR conditions are expected to prevail through Thursday across
all of western and north central Nebraska. Winds will become gusty
Thursday afternoon with the approach and passage of a cold front.
This front will also bring showers and thunderstorms to the area
Thursday afternoon into Thursday evening.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Taylor
Area Forecast Discussion...UPDATED
National Weather Service New Orleans LA
800 PM CDT Wed Apr 26 2023
...NEW UPDATE...
.UPDATE...
Issued at 750 PM CDT Wed Apr 26 2023
Some isolated convection has been developing across portions of
the region this evening with the best coverage just north of our
area along a weak frontal boundary from CenLA to SoMS.
Multicellular clusters have developed in that area where the best
low level lift resides along with a notable instability gradient.
Over our Gulf Waters well within the warm sector, a few isolated
supercells (as seen with the splitting nature) have developed, but
overall motion as been a subtle ENE propagation before the
individual updrafts weaken...at least with the more robust right
splitters.
The 00z sounding and WV imagery show a fairly dry column above
H7, so although a few showers have developed with some
decent/wider updrafts, the drier upper levels are limiting the
vertical growth of these updrafts...at least for now. The lack of
insolation overnight may limit convection a bit, but overall the
mesoscale and globals models are showing pretty much what we`ve
been messaging for the "main event" if you will tomorrow. Timing
of the best convection looks to begin early Thursday. Depending on
cold pool dynamics/strength, the convection may exit the region
at or just prior to noon. Still a bit of uncertainty with that and
a slower solution would no doubt add some hydro potential. Long
story short...no exciting changing in the ongoing forecast and
outside of a few showers, especially west of I55 this
evening...not much to write home about in the immediate near term.
(Frye)
&&
.SHORT TERM...
(This evening through Thursday night)
Issued at 227 PM CDT Wed Apr 26 2023
A warm front has lifted across much of the area today, bringing
better moisture and warmer temperatures across the area. This is
because the area is starting to feel the effect of the digging
shortwave over the Texas panhandle. Some key features are
becoming apparent this evening that could play a major role in
what happens tomorrow morning in terms of severe weather.
Starting with the model data, CAMs have been trending to a more
progressive solution and bringing in the main line of storms
during the mid-to-late morning. The HRRR has been the most
aggressive with this as it has consistently been the CAM with the
earliest arrival. This seems most plausible if the convection
forms into a stout QLCS and cold-pools through here. Models
typically are too slow with strong QLCS`s with a stout cold pool,
so a HRRR solution (a faster one in general) seems most likely.
This would place timing of the line of storms more in the early-
to-mid morning at diurnal minimum. Although it is at diurnal
minimum, instability will be more than sufficient with the
advection of an EML from the Mexican Plateau over us. This brings
stout lapse rates of 7.5-8 C/km and MLCAPE values of 1000-2000
j/kg to work with.
Shear also looks to be sufficient, as the previously mentioned
shortwave transitions from a positive-tilt to a negative-tilt
Thursday morning. That transition will back the winds at the
surface ahead of the storms and provide decent curvature to the
hodographs. From a QLCS standpoint, looking at the 0-3 km bulk
shear, most CAMs suggest values will be right at or just under the
30kt threshold needed for QLCS spin-ups. If we get values greater
than 30kt, the threat for QLCS tornadoes will increase.
Otherwise, the QLCS will mainly bring a damaging wind threat as
well as an isolated tornado threat.
Some key features to track this afternoon and evening are:
1. The outflow boundary pushing south of Dallas. Currently, the
boundary is mostly void of storms. It will be interesting to see
if storms can fire off of it and how they propagate south-
southeastward.
2. The rain and boundary in central Louisiana. Rain has been
present most of the day across central Louisiana and an outflow
boundary from that has made it near Ville Platte, LA. Because the
rain has been there for most of the day, it makes sense to expect
that area to be more stable. Same thing applies to areas north of
that boundary as it cooled the environment as it passed. This
could serve as a blocker to a QLCS moving through that area, and
perhaps breaking it up where that air is most stable. If this were
true, the solution gets messier. When previous model runs broke up
the QLCS, it progressed much slower in the absence of a strong
cold-pool. The line would likely miss portions of the area if it
broke up and eventually ignite cells when daytime heating occurs.
This would be a worse-case scenario as a slower line would have a
higher flash flood threat as well as severe when it takes
advantage of the daytime heating.
In short, currently leaning towards the more progressive solution
that brings a solid QLCS through here in the early-to-mid morning
tomorrow with mainly a wind threat, unless 0-3 km bulk shear
increases. If the line breaks up due to the stability over central
Louisiana, overall threats will increase and shift to late morning
and early afternoon.
Friday, the area will be between two systems and in zonal flow, so
expect a short break in active weather before the next system
comes on Saturday.
&&
.LONG TERM...
(Friday through Tuesday night)
Issued at 227 PM CDT Wed Apr 26 2023
Saturday into Sunday, a shortwave trough is expected to move
through the area, enhancing rain chances again. Easterly surface
winds will help to advect warm air and moisture into the area.
Some weak upper level divergence will help to enhance lifting and
buoyancy in the environment. Numerous showers and storms will be
likely Saturday into Sunday, especially during the afternoon
hours. Shear is fairly low at the moment, looking at the models,
so there could be a strong to severe storm (based on the
instability, moisture presence, etc.). But we are not expecting
anything widespread at the moment. Some localized flash flooding
will be possible Saturday inside of stronger thunderstorms. It is
still early though, so we will see how the system develops over
the next couple of days. There is still a lot of uncertainty in
the models.
Monday into Tuesday, ridging will build into the area. Northerly
surface winds will help to advect stable and cooler, drier air back
into the forecast. Looking at the models, Monday and Tuesday will be
pretty dry overall. Temperatures will be pretty close to normal.
&&
.AVIATION...
(00Z TAFS)
Issued at 626 PM CDT Wed Apr 26 2023
VFR conditions mostly through the early evening before flight
categories begin to drop ahead of the next weather system due into
the region by early Thursday. Convection is forecast to develop
from west to east and impact all terminals across the forecast
area. Brief drops to IFR or lower will be possible in the heavier
storms. Winds may also become variable in and around convection.
Otherwise, some gradual improvement is anticipated later in the
period. (Frye)
&&
.MARINE...
Issued at 227 PM CDT Wed Apr 26 2023
Winds have shifted more onshore today as we start to feel the
effects of a shortwave trough over the southern plains. This
shortwave will likely bring active weather to the waters Thursday
morning. Gradient winds could briefly reach advisory conditions
Thursday afternoon, but otherwise, most of the wind impact will be
with any storm that forms. Otherwise, another system is expected
on Saturday, which could bring higher winds to the waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 62 77 59 80 / 40 90 30 0
BTR 67 81 63 84 / 40 90 20 10
ASD 66 79 65 84 / 50 90 30 10
MSY 68 79 68 83 / 30 90 20 10
GPT 67 75 66 81 / 40 90 40 20
PQL 65 76 66 83 / 20 90 40 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
UPDATE...RDF
SHORT TERM...JZ
LONG TERM....MSW
AVIATION...RDF
MARINE...JZ
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
953 PM CDT Wed Apr 26 2023
...New UPDATE...
.UPDATE...
Issued at 953 PM CDT Wed Apr 26 2023
A few showers persist over northeast MS at midevening, associated
with weak shortwave traversing the Midsouth. Upstream, GOES water
imagery shows a closed upper low over the TX panhandle. Strong to
severe thunderstorms over central and east TX, along an east-west
oriented stationary front.
The late evening and overnight hours will hold limited rainfall
potential. By 12Z, however, shortwave ridging will have lifted
east, exposing the Midsouth to diffluent flow aloft, and strengthening
low level warm advection. Modest elevated instability above 850mb
will support thunder, mainly south of I-40 toward sunrise.
Increased thunderstorm chances will arrive Thursday afternoon.
Over north MS, 00Z HRRR model depicts mixed-layer CAPE exceeding
1000 J/kg, 40-45 knots of 0-6km bulk shear, and mid level lapse
rates near 7C/km. Cloud cover could limit coverage of surface-
based storms, especially after midevening Thursday.
PWB
&&
.SYNOPSIS...
Issued at 256 PM CDT Wed Apr 26 2023
Showers are moving across north Mississippi and light
echos are beginning to show in eastern Arkansas. Showers will continue
to become more widespread and thunderstorms are possible tonight.
Showers and thunderstorms will continue through the day tomorrow
before clearing out late Friday. A brief lull will occur before
showers takeover for the weekend.
&&
.DISCUSSION...
(This evening through next Tuesday)
Issued at 256 PM CDT Wed Apr 26 2023
Shower chances will continue to increase and encompass
the entire Mid-South over the next few days as we enter an unsettled
weather pattern. A warm front is lifting north causing rain chances
to increase as well as thunder chances. It is possible for this
warm front to stall, causing showers to essentially split the CWA
and provide showers to the north and to the south, but practically
avoiding the TN/MS state line, but low confidence in this
occurring.
While some isolated thunderstorms are possible tonight, Thursday is
the better chance for thunder as a low pressure system moves across
the region. Instability is there, but shear and CAPE values are not
favorable for strong storm development. The associated cold front
with the aforementioned system allows below normal temperatures to
continue. Despite having showers and thunderstorms in the forecast
for a few days in a row; QPF values are 1-2" with most of the
rainfall occurring on Thursday.
Shower and thunder activity should diminish early Friday afternoon.
After the system moves through, a brief lull for the remainder of
the afternoon before showers return for the weekend. Long term
models are trending for a more dry weekend, due to a chance of
being in the warm sector of the aforementioned low pressure system.
We will continue to monitor the weekend, but it looks like any
thunder chances are limited.
DNM
&&
.AVIATION...
(00Z TAFS)
Issued at 642 PM CDT Wed Apr 26 2023
VFR conditions will prevail initially at TAF sites tonight.
However, a deterioration to MVFR/IFR conditions are expected
towards sunrise on Thursday. Rain showers are expected through the
night with any confidence in elevated thunderstorms remaining to
low to include in TAFs at this time. VCSH possible during the day
on Thursday with a possibility of VCTS late Thursday afternoon
into early Thursday evening. Light NE/E winds will increase
tonight to 7-10 kts and veer generally SE/S on Thursday.
CJC/GNC
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...DNM
AVIATION...GNC
Area Forecast Discussion
National Weather Service Raleigh NC
1000 PM EDT Wed Apr 26 2023
.SYNOPSIS...
A series of low amplitude, mid and upper-level disturbances will
result in periods of lift along and north of a frontal zone over the
Southeast through Thursday. That front, and an accompanying area of
low pressure, will then lift north across NC on Friday.
&&
.NEAR TERM /TONIGHT/...
As of 1000 PM Wednesday...
850-700 mb-centered theta-e advection and Fgen, poleward of a
surface through low-level frontal zone over the Southeast, will
continue to focus periods of mostly light, stratiform rain over
(particularly over the southeastern half) cntl NC tonight. That
regime will otherwise continue to favor 5-10 thousand ft ceilings
and associated cloudy or mostly so conditions, with near steady to
slowly falling temperatures in the 50s.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 210 PM Wednesday...
The upper level disturbance which will generate increased cloud
cover and a chance of rain tonight will be exiting eastern VA/NC
around daybreak Thursday. In its wake will be a period of short wave
ridging before the next storm system approaches. This system with
closed low over KS/OK at 12Z Thursday will lift northeast and open
up over the MO Valley on Thursday before rapidly lifting into the OH
Valley and mid-Atlantic on Thursday night. NWP guidance has trended
faster with the ejection of the upper low which now results in a
faster arrival of widespread showers from the west late Wednesday
evening and overnight.
Thursday morning will start off mostly cloudy with some lingering
light rain or sprinkles across the Coastal Plain that should diminish
by mid morning. A period of mostly cloudy skies and mainly dry
weather is expected for Thursday afternoon with chilly conditions.
With a northeast flow highs will range in the mid 60s to around 70.
Rain chances will increase from the west on Thursday evening with
rain chances rapidly increasing from the west overnight. NWP guidance
indicates an increase MUCAPE from the south during the predawn
hours, mainly across the southeast likely requiring the mention of a
slight chance of thunder toward daybreak. Lows on Thursday night
will range in the 50s. -Blaes
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 228 PM Wednesday...
Complicated upper (and surface) level setup will continue Friday
into the weekend, with an upper low over the Great Lakes and a
series of shortwave troughs rotating through the Southeast/Mid
Atlantic states. Friday will start with a shortwave trough over NC
and a somewhat Miller-B-like surface pattern with a low over the OH
Valley and a secondary coastal low to our southeast. Showers (and
isolated thunderstorms) should be ongoing at daybreak, but today`s
12Z guidance is indicating most of that precipitation moving out of
the area by early afternoon. This is a few hours earlier than
previous guidance was suggesting and it`ll be interesting to see if
the 12Z suite of ensembles agree with this faster solution. For the
time being I maintained 80-90 PoPs Friday morning and afternoon,
tapering off from southwest to northeast Friday evening. There is
low confidence in exactly how the severe weather potential will play
out during the day Friday. We will start with a few hundred J/KG of
MUCAPE in the morning, and with BL destabilization later in the day
we should be able to realize around 1000 J/KG of MLCAPE in the
afternoon. This will also be around the time we get some mid level
drying working in from the southwest and some weak shortwave ridging
aloft. I will maintain at least a mention of thunder during this
period as the showers are exiting the area. Tonight`s run of the 00Z
HREF and HRRR could certainly provide some additional insight.
Saturday is looking dry at this point as mid level ridging takes
hold over the area. Temps will be on the mild side with highs
generally reaching the upper 70s to lower 80s.
Meanwhile, another upstream shortwave will be approaching the area
from the southwest Saturday afternoon with increasing cloud cover
throughout the day. Moisture transport is maximized late Saturday
night into Sunday morning and most ensembles only indicate a 15-20
percent chance of rain Saturday evening. This will increase
dramatically Sunday morning at which point upper level divergence
will be maximized and showers should overspread the entire area by
daybreak Sunday. A cold front will move through the area late Sunday
night with dry weather and surface ridging returning on Monday. With
precip ongoing through the day and extensive cloud cover, highs
should be within a few degrees of normal (low to mid 70s).
Monday through Wednesday should be dry with west/northwesterly flow.
Highs in the upper 60s, lows in the 40s.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 746 PM Wednesday...
Areas of light rain continue this evening mostly across southern
portions of central NC. Other than some fleeting MVFR conditions at
KFAY the next few hours, mostly VFR conditions are expected at all
terminals through ~04Z. Beyond 04Z, a surge of lower-level moisture
and additional light rain will move in from the southwest dropping
all sites to MVFR by ~08Z. IFR ceilings will then be possible near
sunrise Thursday morning at all sites, but confidence is still
lacking a bit especially at KINT/KGSO/KRWI. Any lingering IFR
ceilings will lift to MVFR by mid-morning, and latest guidance
suggests all sites may hang on to MVFR ceilings through the end of
the 24 hr TAF period. The only exception would be KRWI where
ceilings may flirt with low-VFR ceilings (3500-4000 ft AGL) by 19Z
or so. Light winds at 5 to 10 kts are expected through the period
with mainly northeast to east winds through period.
Outlook: Another storm system will bring unsettled weather and sub-
VFR restrictions in periods of rain Thursday night into early
Friday. After a lull on Saturday, another storm system will spread
adverse aviation conditions across the area on Sunday and Sunday
night with improving conditions on Monday.
&&
.HYDROLOGY...
As of 1230 PM Wednesday...
A fairly significant rain event last weekend produced average
rainfall amounts of around a half inch to an inch and a half with
localized amounts in excess of two inches across the Triangle area,
the eastern Piedmont, Sandhills and Coastal Plain. Lighter amounts
of around a half inch or so fell across the western Piedmont. Over
the past few weeks the region from Laurinburg northeast across the
Sandhills and Triangle area to Lake Gaston has had significant rain
and soil moisture values range close to the 90th percentile of
normal.
Streams, creeks and rivers that experienced significant rises over
the weekend and early this week have largely fallen as the water
works its way through the river system. While streamflows as of this
morning are generally near normal, some waterways in the Neuse River
Basin, including the portions of the Triangle area, and the Tar
River Basin are above normal while in the Triad area they shade
slightly below normal.
Multiple precipitation events are forecast over the next several
days including a very light event through early Thursday morning.
This will be followed by another event for late Thursday into Friday
morning with amounts of a half inch to an inch and a half. After a
break on Saturday another event on Sunday will bring perhaps
another half inch to an inch of rain.
While the additional rainfall over the next five days raises some
concern, the risk of widespread or significant flooding appears
limited. The greatest threat will be in areas where rain rates and
runoff will be highest. At this time, the potential for higher rain
rates is from the U.S route 1 area east late Thursday and Friday and
again on Sunday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...Blaes
LONG TERM...Leins
AVIATION...Luchetti
HYDROLOGY...Blaes/Smith
Area Forecast Discussion
National Weather Service Shreveport LA
1028 PM CDT Wed Apr 26 2023
...New UPDATE...
.UPDATE...
Issued at 947 PM CDT Wed Apr 26 2023
Tornado Watch 170 remains in effect for areas south of I-20 over
much of East Texas and parts of North Louisiana through 1 AM Thu.
For now, the primary concern remains some very large hail with the
strongest convection along and south of a northward migrating warm
front across Deep East Texas. However, still cannot rule out a few
rotating storms capable of producing a tornado over the next few
hours across the Tornado Watch area. For this update, have trimmed
back areas where severe wording is included to better align with
the aforementioned watch area. Otherwise, an additional growing
concern is the threat of heavy rainfall and flash flooding as this
convection slowly advances eastward across many areas that already
observed 1-2 inches of rainfall earlier today. As a result, expect
the flooding threat to increase through the remainder of tonight
along and south of I-20 while areas farther north will see lesser
amounts of rainfall and therefore little if any flooding threat.
Beyond these changes, temperatures were also adjusted to reflect
the latest observed trends. The remainder of the forecast is on
track. Updated text products have been issued, and grids will be
available shortly.
/19/
&&
.UPDATE...
Issued at 713 PM CDT Wed Apr 26 2023
Tornado Watch 170 is now in effect through 1 AM CDT Thursday for
much of East/Deep East Texas and parts of North Louisiana south
of I-20. A warm front continues to lift slowly northward from
Sam Rayburn and lower Toledo Bend country, and these areas invof
of the warm front will be the focus of strong to severe convection
through the remainder of this evening and into the overnight hours
early Thursday morning.
/19/
&&
.SHORT TERM...
(This evening through Thursday Night)
Issued at 344 PM CDT Wed Apr 26 2023
As expected, the morning/early afternoon convection has
convectively reinforced the cool/stable air mass across much of E
TX/Cntrl LA this afternoon, although the air mass has begun to
modify some as the warm front has begun to lift N into portions of
Deep E and the Wrn sections of E TX. This is evident in the lower
to mid 60s isodrosotherms having recently advected back N into
these areas, as well as some scattering of the cu field noted on
the visible satellite imagery. However, time is running out on
the advancement of the warm sector N across E TX/N LA, as
elevated convection has become numerous and spread E into NE TX
along and N of I-20, which should help to again convective
reinforce the front from mixing much farther N during the evening.
An isolated severe threat currently exists across the I-20
corridor of E TX, as bulk shear near 50kts and 2-6km lapse rates
remain steep atop the warm front that is orientated farther S.
However, believe that the main focus for severe convection will
occur this evening through a portion of the overnight hours as
convection continues to deepen ahead of a sfc low between ABI and
COM, which will shift E along a W to E sfc bndry convectively
reinforced to near and just S of the I-20 corridor from the DFW
Metroplex into E TX/NW LA. This will occur once large scale ascent
increases along these sfc features ahead of the closed low over
the TX Panhandle, which will eject NE into Wrn OK during the
evening. The HRRR remains consistent with earlier runs (and in
better agreement than the other CAMs) with the convection entering
the Wrn sections of E TX by the early to mid evening hours, with
the moderate SBCapes expected to spread a bit farther N into E TX
by that time. Thus, the convection should begin to intensify as it
approaches Lower E TX, as it transitions potentially into a SE
propagating MCS across Deep E TX/WCntrl LA during the late evening
through a portion of the overnight hours.
Have trimmed back the severe wording to these areas tonight, but
also expanded on the heavy rain mention as consensus amongst the
short term progs suggest that widespread rainfall amounts of 2-3+
inches is possible across much of E TX/Srn AR into portions of N
LA. The storm intensities should gradually diminish overnight as
the instability wanes, and a potential convective cold pool shifts
ESE across the region in wake of the convection. The convection
remains progged to diminish after daybreak Thursday across Cntrl
LA, although the opening low will remain conducive for additional
isolated to scattered convection development during the day over
the region although this should diminish from W to E as drier air
begins to entrain ENE beneath the opening trough. Did taper back
max temps slightly Thursday afternoon given the extent of wrap-
around cloud cover which looks to linger through a better part of
the day, before drier air begins to mix ESE into the region late
in the day with the passage of a weak cold front. A return to
below normal temps is expected as the cigs scatter out Thursday
night, with cool conditions returning through the overnight
period.
15
&&
.LONG TERM...
(Thursday night through next Tuesday)
Issued at 344 PM CDT Wed Apr 26 2023
Friday morning will see the quiet conditions in the wake of
Thursday`s showers and storms continue for a brief window of time.
The break in the rainfall looks to be short-lived, however, as the
unsettled pattern which brings our mid-week storms will continue
late into the week. Upper level flow around a broad area of
troughing reaching from the Rockies in the west to the Appalachians
in the east will sweep Thursday`s trough away to the north and east,
with another shortwave quickly on the way, pushing south along the
Front Range and into north Texas, with a closed low potentially
cutting off by late Saturday. This feature will provide the forcing
necessary for another round of showers and possible storms to begin
as soon as Friday afternoon north and west, expanding areawide
overnight and remaining with the ArkLaTex through the day Saturday
before finally clearing out overnight into Sunday as the closed low
opens back into a shortwave and is absorbed by the larger area of
troughing still situated over the Great Lakes region early next
week.
Temperatures will be fairly variable through the long term period,
with a slight rebound into the upper 70s to low 80s Friday before
Saturday`s rainfall keeps highs in the upper 60s to low 70s. Sunday
will see a return to more seasonable temperatures in the mid to
upper 70s, with quieter, drier conditions and a slight warming trend
to follow into early next week.
/26/
&&
.AVIATION...
(00Z TAFS)
Issued at 713 PM CDT Wed Apr 26 2023
For the 27/00Z TAF period, cigs continue to vary widely as strong
to severe convection increases across our airspace this evening.
The trend will be for deteriorating flight conditions overnight as
showers and thunderstorms become more widespread, bringing MVFR/IFR
cigs and greatly reduced vsbys as well with associated heavy rain.
The strongest storms could also contain large hail, damaging winds
and even an isolated tornado cannot be ruled out ahead of a cold
front shifting into the region. Convection should begin to wind
down by 27/12Z as the cold front continues its eastward push, and
winds veer more W/NW with speeds around 10-15 kts and much higher
gusts likely invof of convection.
/19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 59 72 53 81 / 100 30 0 0
MLU 60 77 57 80 / 100 60 10 0
DEQ 54 67 48 78 / 90 50 0 10
TXK 56 70 51 79 / 100 30 0 10
ELD 56 73 53 78 / 100 50 10 0
TYR 60 71 52 81 / 100 20 0 10
GGG 59 72 52 81 / 100 20 0 10
LFK 64 74 53 84 / 100 30 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...19
LONG TERM....26
AVIATION...19
...Update to aviation forecast discussion...
.DISCUSSION...
Issued at 238 PM CDT Wed Apr 26 2023
Key Points:
- Light rain possible east-central Kansas tomorrow morning, and in
north-central Kansas on Friday.
- Temperatures stay near or slightly below average.
Currently this afternoon, the overall pattern is not too much
different than yesterday. Our upper low that was over the Rockies
yesterday has moved over the Texas Panhandle, with surface low
pressure still well to our south over west Texas. With high pressure
to our northeast, this is keeping easterly flow in place over our
area. With drier air to east compared to more moist air farther
southeast, this trajectory has remained unfavorable for
precipitation to move much northward from its location over southern
Kansas and Oklahoma. Probably no major complaints about that though,
as the drought has been much worse over this area. As the low moves
east overnight and Thursday morning, some light rain may briefly
move up into our area. The GFS and FV3 remain outliers with more
precipitation farther north, but given the drier air over our area,
the consensus solution is for just some light showers along and
southeast of I-35. Would expect any rain amounts to be below a
tenth of an inch.
After the first system departs on Thursday, a second upper trough
will approach on Friday, following a similar track southeast into
Texas as the first. This second trough will be influenced by a
deeper upper low diving into the Upper Midwest. So a bit more
moisture may be able to reach into northeast Kansas this time. Still
not expecting much in the way of precipitation, as the best height
falls and isentropic ascent will remain both northeast and southwest
of the area. Nevertheless, most guidance has at least some light
precipitation ahead of the upper trough axis, particularly across
north-central and central Kansas. Temperatures Thursday and Friday
will be influenced by cloud cover, but highs will generally be in
the 60s.
The upper low will deepen over the eastern CONUS over the weekend,
supporting cool and dry flow over the Central Plains. Subsidence
behind the deep trough will at least keep skies mostly clear. So
while this will keep nights on the cooler side through early next
week, daytime highs will be able to warm to near or just slightly
below average. A warming trend may then arrive by mid next week as
the upper low slowly slides off to the east.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 621 PM CDT Wed Apr 26 2023
VFR at terminals with satellite showing increasing cloud cover and
lowering bases overnight. Much of the rain is likely to remain
south of terminals through the forecast period, despite the fact
that the RAP model tries to bring scattered showers as far north
as TOP. Lowering stratus in the 030-050kft range is likely aft 18Z
with the indication from soundings of MVFR cigs at KMHK in the
afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Reese
AVIATION...22