Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/25/21
Area Forecast Discussion
National Weather Service La Crosse WI
1000 PM CDT Wed Mar 24 2021
.SHORT TERM...(This evening through Thursday)
Issued at 204 PM CDT Wed Mar 24 2021
Forecast concerns through the short term will be the rain ending,
brisk northwest winds, and if we`ll see much in the way of
breaks/fog potential before the next upstream storm system heads
Water vapor satellite imagery highlights the closed 500mb low
pressure system over the Upper Mississippi Valley with another
closed low over Arizona/New Mexico. A weak shortwave was noted
over the Dakotas along with a stronger open wave from the Pacific
Northwest into British Columbia. The WSR-88D radar mosaic has a
the deformation band precipitation is wrapping around the closed
low and covers a large part of eastern Minnesota. Closer to the
low and across parts of western Wisconsin, we have been seeing
patches of steady rain, on and off light rain and drizzle. Through
12Z, most local rainfall reporters received at least .25 to .50
of and inch, with several locations reporting .5 to 1 inch of
rainfall. Some of the higher amounts were 1.2 inches at Guttenberg
Dam 10 in Clayton Co. and 1.57 inches at Necedah in Juneau Co.
At Midday, surface low pressure was centered near Eau Claire with
a tight pressure gradient on the west side of the low pressure
system. Visible satellite imagery shows a large mass of clouds
associated with this system. The RAP is fairly optimistic in
losing the clouds over the southwest part of the forecast area
later this evening with drier air advecting in from the west. Some
mid-level moisture is expected to be drawn northeast ahead of the
shortwave tracking in from the Dakotas. With the wind decoupling
by morning, could see some patchy fog develop. Right now the NAM
is the only one that is aggressive with it while the RAP/HRRR/LAMP
data are not. Many highs occurred in the morning in the mid 40s
to lower 50s. As the storm system continues to pull away, we`ll
see temperatures fall through 40s into 30s. Lows tonight should be
in the upper 20s to mid 30s.
Moisture transport increases Thursday morning aloft, however the
deep moisture (10 deg C or greater) and 850mb jet focus is more
across Missouri into Illinois during the day. The 700mb warm
advection does spread north into the forecast area with some
steeper lapse rates as some stronger energy with part of the open
wave moves into the region. The mid level frontogenesis is more
focused from Missouri into Illinois. Through Thursday afternoon,
the forecast area will be on the northwest edge of the
precipitation. There may be some virga or sprinkles farther north,
but for now will include chance of precipitation in the 15 to 30
percent range for the southern quarter of the forecast area. Highs
Thursday should top out in the mid 40s to lower 50s with
northeast winds 5 to 15 mph with some stronger gusts.
.LONG TERM...(Thursday night through Wednesday)
Issued at 204 PM CDT Wed Mar 24 2021
Over the upcoming days, the chances for additional precipitation
look to be centered on the weekend and then possibly early next
week, although there look to be some model differences with this
After the system that moves past the region Thursday afternoon
and night, there looks to be a brief period of some upper level
ridging over the area into Friday. However, this ridging quickly
breaks down with a long wave trough moving across the western
conus and toward the Midwest. A short wave trough embedded in the
long wave trough looks to advance northeast across the Friday
night and Saturday morning followed by another short wave trough
coming in from the northwest for Saturday night. The first short
wave trough for Friday night looks to take a track that will go
right across the local area and produce a round of moderate to
possibly strong pv advection in the 500-300 mb layer. In the low
levels, a weak area of low pressure is expected to move across
Iowa into southern Wisconsin. In the warm air advection ahead of
the surface low, good isentropic up glide should develop with this
expected to be on the order of 2 to 4 ubar/s on the 290K surface.
There also looks to be some moisture transport on the surface
into the area, but this does not look to be all that strong. A
weak to moderate band of mid-level frontogenesis should set up on
the northwest side of the surface low to help form a deformation
zone of precipitation. Temperatures look to be warm enough for
this to fall as mainly rain, although there could be some light
snow at the beginning across central Wisconsin late Friday night.
The system for early next week looks to be a bit more muddled. A
nearly cut off upper level low over the Desert Southwest this
weekend will get kicked northeast ahead of a stronger system
coming in off the northern Pacific. The differences in the models
start to show up in how far north this system will come along with
its strength. The 24.00Z ECMWF shows a farther north and stronger
system than either the 24.12Z GFS or GEM. This spread is also
apparent in the 24.00Z EPS with some members showing the system
taking a farther south track with the area staying dry while some
do show some light precipitation spreading over the region. The
incoming system that acted as the kicker then looks to turn
northeast with the upper level low moving across Canada with a
trailing positive tilt long wave trough coming into the area
Tuesday/Tuesday night. With the uncertainty of this system will
have some low precipitation chances going from Monday night into
.AVIATION...(For the 06z TAFS through 06z Thursday night)
Issued at 1000 PM CDT Wed Mar 24 2021
Cigs: MVFR cigs through the evening, with improvement expected
overnight as the responsible area of low pressure pulls off to the
northeast. Looking to sit under a bkn deck of VFR cigs then for Thu
with better chances for clearing later Thu night into Fri.
WX/vsby: Some hints in a few of the meso models that patchy fog
and/or low cigs could develop overnight, moreso for KRST. This is a
trend that is starting to increase a bit (compared to some prev
model runs). For the moment, with stay the course with no fog/low
stratus - but will keep a close eye on things.
Winds: west/northwest and decreasing tonight. Staying fairly light
Thu and swinging more to the northeast.
Area Forecast Discussion
National Weather Service Binghamton NY
1041 PM EDT Wed Mar 24 2021
Rain will taper off this evening, followed by a warm and dry
day Thursday. A low pressure system will bring more rain
Thursday night into Friday. This back-and- forth weather pattern
will continue this weekend; dry Saturday and more rain Sunday.
.NEAR TERM /THROUGH THURSDAY/...
1030 PM Update...
Made some minor adjustments to cloud cover based on latest
METSAT and observations. Also, there may still be some light
rain across Catskills over the next hour or two, but removed any
other mention of rain after midnight.
445 PM Update...
Forecast remains mostly on-track and just made some minor
adjustment to rain chances and cloud cover through this evening,
based on latest observations and RADAR. Rainfall is moving out
slightly faster than was previously forecast, so have adjusted
accordingly. The rain moves out this evening, but low level
moisture holds on across the Catskills and Poconos, with mostly
cloudy conditions and fog through the night.
Mosaic radar imagery shows a widespread batch of rain from central
and southeast PA/eastern VA/DE/NJ north into central and eastern NY.
This rain was associated with a low-level warm advection wave. The
thermal structure of this wave showed that it was warm core. It will
continue to move off to the northeast this afternoon and evening. In
its wake the flow at 925 mb will remain moist and fairly mild with
925 mb dewpoints in the upper 40s. Below 925 mb down to the surface
there was a moist southeasterly flow which was advecting
temperatures in the upper 40s and lower 50s. With nightfall and
some boundary layer cooling coupled with upslope flow we see a
lot of low clouds and fog over the higher elevations especially
Poconos/Catskills and other higher terrain areas in northeast PA
and central NY. So we will continue to mention patchy to areas
of fog in these areas tonight. For POPs we have switched to
using the latest HRRR in the very near term hourly POPs as it
has the best handle on the evolution of the precipitation
shield. Later in the ESTF period, we switch back to using a
blend of mesoscale model guidance for our hourly POPs. The
precipitation will end in the Finger Lakes by 20z, and the rest
of central NY/northeast PA by 00z or so. Then there just will be
low clouds with some fog over the higher terrain tonight.
For Thursday, the low-level flow turns more southwest and with
subsidence, upper level ridging aloft and insolation the low
clouds will break up leading to a very warm day for late March.
We expect a lot of sunshine by afternoon. Some daily record
highs could be challenged with maximum temperatures in the low
to mid 70s.
Then Thursday night, another storm system will be rapidly
approaching from the lower and mid Mississippi valley. This feature
will begin to spread cirrus across our area Thursday afternoon with
a rapid cloud cover increase as a strong upper level jet moves into
the Ohio Valley by 06z Friday. The upper level jet will induce
a strong low- level southwest jet around 850 mb which noses up
to NY and PA by 06z as well. This will lead to rapid developing
isentropic ascent or warm air advection. Additionally, it will
tap into the Gulf of Mexico and have a strong moisture feed.
Thus clouds will increase between 22z Thursday and 04z Friday
with precipitation breaking out as well. By 12z Friday QPF is
looking like around .50" with more expected Friday. The system
is moving quickly so for now not expecting any hydro issues
Friday. Showalter Indices actually go below 0C late Thursday
night and with strong warm advection and a sheared flow, I have
added a slight chance for thunder into the grids.
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A storm system pulling out of our region and into Northern
Maine will drag brisk winds across portions of Upstate NY and
Northeast PA Friday. Showers will taper off Friday afternoon,
with a thunderstorm possible early in the day across our
northeastern counties where the atmosphere will remain unstable.
As cooler, drier air moves across the lakes, winds will gust
between 25 and 30 mph across most of NY and PA, with gusts of 35
mph or higher along the lake plain and over high terrain areas
of the Twin Tiers.
Saturday will be quiet but still milder than normal. Temperatures
will reach the 50s.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
An active pattern will begin Saturday night when a low pressure
system tracks out of the Great Lakes. A few rain showers could
reach the western portion of our forecast area before sunrise.
Showers will become likely during the day on Sunday as moisture
overspreads the region.
Much cooler air behind the storm will pull a mix of rain and
snow showers into NY/PA Sunday night.
Drier conditions will prevail Monday with a chance of lake
effect rain or snow showers over the far north.
Quiet weather and above normal temperatures will return for
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
An area of lower level stratus clouds remains locked over much
of the area this evening. Our area will see a persistent south-
southeast flow which will upslope into the hills along and east
of I-81, with more downsloping and eventual drying across the
northern Finger Lakes and Syracuse area. The steady rain has
exited the area at this time, but pockets of fog and drizzle are
expected overnight; again mainly across the Poconos and Catskills.
As for restrictions; SYR is expected to be mainly VFR overnight,
but could see occasional MVFR CIGS for the next few hours. RME
will remain MVFR to occasionally fuel alternate through about 09z
early Thursday morning, then lifting to VFR. ITH is forecast to
remain MVFR Fuel alternate due to CIG restrictions through the
entire overnight period, finally scattering out and lifting
to VFR between about 12-14z Thursday morning. With the south-
southeast flow in place, feel at this time, that IFR restrictions
are unlikely here. ELM is also at MVFR Fuel alternate CIG
currently, and is also expected to remain so through the
overnight. Guidance was a little more insistent that ELM could
briefly see IFR or Alt Minimum CIGS for a few hours this
evening, so included a tempo group in the TAF for that, between
25/02-06z. BGM will continue to see IFR CIGS overnight, and is
expected to see LIFR/ Alt minimum CIGS develop after about
25/05z, continuing until 25/12-14z. At AVP, it`s currently MVFR
fuel alternate and is expected to deteriorate to IFR after about
04z, then Alt Minimums possible after about 25/08z...along with
some IFR vsby restrictions in fog here.
For all TAF sites, expect pretty quick improvement back to VFR
between about 25/13-16z, with VFR conditions then expected
areawide Thursday afternoon.
Some marginal LLWS still present at SYR through about 25/06z
late this evening. Otherwise, expect south-southeast winds less
than 10 kts overnight, becoming south-southwest 6-12 kts on
Thursday Night through Friday...Rain showers, restrictions, and
possible low level wind shear from passing low pressure system;
embedded thunderstorms possible.
Friday night through Saturday evening...Mainly VFR.
Late Saturday night through Sunday...Another system with rain
and restrictions. Some snow could briefly mix in Sunday night.
Record highs for March 25th
Syracuse 78F in 1988; forecast high is 77F
Binghamton 72 in 1988; forecast high is 71F
Scranton/Wilkes-Barre 76 in 1910 and 1913; forecast high is 75F
Area Forecast Discussion
National Weather Service Cleveland OH
916 PM EDT Wed Mar 24 2021
Low pressure will develop over northeast Texas this evening,
tracking across the mid-Mississippi Valle tomorrow and to near
Lake Erie by Friday morning. High pressure will build in behind
the departing low pressure on Saturday before another low
moves eastward across the Great Lakes region.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
915 pm update...
No changes to the overnight forecast were made with this evening
Very warm conditions with partly sunny skies are currently
observed across the area with surface temperatures generally in
the low 70s and dew points in the upper 40s to near 50, which is
a fairly pleasant day for most. RAP mesoanalysis has about 250
J/kg of MLCAPE though this is expected to increase to just over
500 J/kg with about 40 to 50 knots of vertical wind shears.
Minimal MLCIN is observed in analysis data with some convective
development possible over Lake Erie, far northeast Ohio, and
northwest Pennsylvania later this evening. Isolated severe
weather is possible given the wind profile, but it`s a long shot
because of limited, skinny instability and a steadily drying
Decreasing cloud cover associated with a drying airmass is
expected tonight due to brief upper-level ridging. Gusty winds
from earlier this afternoon should diminish and become light and
variable as well tonight.
A potent shortwave trough located over central Texas Thursday
morning will become negatively tilted as it lifts northeast
towards the Great Lakes region on Thursday and Thursday night,
located near Indiana by Friday 06Z. At the surface, the low
associated with this upper- level trough will work its way
northeast towards the Great Lakes region during this same time
period, rapidly deepening to near 990mb by 06Z Friday. Rain
showers with some embedded thunderstorms will overspread the
region Thursday evening, becoming more numerous Thursday night.
A very strong wind field will be present with this system,
producing very strong winds Thursday night, especially with the
downward momentum behind the cold front, which will be working
its way eastward across the forecast area between 06-12Z Friday.
During this time, wind gusts of up to 50 knots will be
possible, for which we have a High Wind Watch in effect for.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A complicated and highly-variable high wind event will be ongoing
across the area at the beginning of the short term period. Great
uncertainty remains on the evolution of a convectively-induced,
compact surface low pressure system which should be located in the
vicinity of southern Lake Huron early Friday morning. Have opted to
keep the high wind watch in place across the entire area at this
time and will re-evaluate any potential warning/advisory changes
Sometime during the early morning hours on Friday, we should switch
from a warm to cold air advection regime, allowing spurts of
enhanced wind just above the surface (i.e. 50 to 60 knots at 925 mb)
to mix down to the surface. This would result in widespread 55 to 60
mph gusts with isolated pockets of 65 to 70 mph located within
convection. not High winds should persist only for an hour or two as
the enhanced pocket of wind quickly sweeps east across the region
through the morning. Any higher wind gusts will quickly diminish
through the morning, concluding across Northwest Pennsylvania by the
Brief surface high pressure and upper ridging will settle in across
the region Saturday morning and afternoon, making for quite a
pleasant weather day with highs in the mid to upper 60s. Not
anticipating much in the way of a lake breeze with the pressure
gradient increasing from the west through the day, though the best
chance would appear to be along the northeast lakeshore into NE OH
and NW PA. By Saturday night, an upper trough and surface low
pressure system will move east across the Great Lakes, increasing
precipitation chances Saturday night into Sunday morning. Some
elevated instability may also allow for a few rumbles of thunder as
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Precipitation will continue to decrease in coverage across the
region Sunday morning as low pressure continues east into Quebec.
This will set the stage for upper ridging and surface high pressure
to settle in once again across the area, allowing for fair and quiet
weather to persist through at least Monday with high temperatures
in the 50s under mostly sunny skies. Fair and quiet weather
may persist into Tuesday with warmer temperatures into the 60s,
although some uncertainty lies on embedded shortwave trough
evolution within the large scale ridge, as well as the evolution
of the next large-scale trough across the Central CONUS. There is
better agreement in model blends of increasing precipitation chances
.AVIATION /00Z Thursday THROUGH Monday/...
Generally VFR is expected through this TAF period with active
and impactful weather for aviation just beyond this 24 hour TAF
period. Scattered to few clouds around 7K will decrease this
evening after sunset. Gusty winds from this afternoon will also
slowly relax after sunset this evening. Southerly winds around
5 to 10 will continue tonight into Thursday. A low pressure
system will start to approach the area late Thursday which will
shift the winds from the southeast or east late in the day
across western Ohio. ERI will have a light lake breeze for a
couple hours this evening before shifting back from the south.
High and mid level clouds will increase late in the TAF period
as the next storm system approaches the region.
Outlook...Non-VFR possible Thursday evening through Friday with
periods of rain showers and some thunderstorms. Winds will be
elevated on Friday and widespread gusts in excess of 35 knots
are expected. Isolates gusts to 50 knots are possible.
Mainly south to southwesterly winds, 10 to 15 knots, will prevail
across the lake through tonight before becoming easterly ahead of a
warm front. Easterly winds will become near 20 knots by Thursday
evening, increasing to near 30 knots and shifting more southerly as
a warm front moves north across the lake. Southerly winds will
quickly shift towards the southwest, then west, increasing to 35
knot Gales late Thursday night into Friday morning. Widespread
wind gusts of near 50 knots will be possible across the lake Friday
morning through the early afternoon. Given the prolonged and
enhanced westerly flow, we will also likely need a low water
advisory for the western basin of the lake.
Westerly winds will quickly decrease to 10 knots or less by late
Friday afternoon into Friday evening. Light flow across the lake is
expected through Saturday. Southwest to west flow increases once
again Sunday morning towards 20 to 25 knots. West to northwest flow,
20 to 25 knots, will persist through much of Sunday. A Small Craft
Advisory will likely be needed. Light northwest flow will return
across the lake by Sunday night into Monday.
OH...High Wind Watch from late Thursday night through Friday
morning for OHZ010>014-020>023-030>033-038-089.
High Wind Watch from late Thursday night through Friday
morning for OHZ003-006>009-017>019-027>029-036-037-047.
PA...High Wind Watch from Friday morning through Friday afternoon
MARINE...Gale Watch from late Thursday night through Friday morning for
Gale Watch from Friday morning through Friday afternoon for
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1141 PM EDT Wed Mar 24 2021
There is ample moisture underneath a deepening post frontal
inversion to support some degree of low end VFR and/or MVFR based
stratus. These clouds are already approaching MBS. Based on the
progression of low level cold air, these clouds will slowly work
southeast across the remainder of the terminals overnight. Diurnal
mixing on Thursday should then erode these low clouds late morning
or early afternoon.
For DTW...The edge of the low level cold air and stratus is forecast
to approach metro by 12Z. There is some uncertainty as to how well
these clouds will hold together at metro, especially given that the
cloud layer may be more shallow in this region and thus easily mixed
out during the course of the morning Thurs.
.DTW THRESHOLD PROBABILITIES...
* Low in ceilings below 5000 feet overnight and Thursday morning.
High Thursday night.
Issued at 415 PM EDT Wed Mar 24 2021
Showers expanded into Lower MI from textured cumulus that moved in
from Indiana during early afternoon. These clouds and showers
represent increased surface dewpoint in the moisture axis and low
pressure warm sector over the region. The low level moisture and
afternoon surface heating has surface based CAPE above 500 J/kg but
still less than 1000 J/kg in hourly mesoanalysis. More telling is
MLCAPE struggling to exceed 250 J/kg but still forecast to rise
above 500 J/kg in RAP solutions. So far, this has been adequate for
a couple thunderstorms in the Tri Cities area and suggests
continuation of efforts to monitor convective intensity capable of
facilitating strong wind gusts already in the background wind field,
especially if scattered cells can congeal into linear structures
along the cold front. The wide range of hi-res model guidance paints
the picture of uncertainty on convective character with the forecast
leaning toward a tendency for struggling organization and
longevity due to overall limited instability up against the strong
wind profile. The chance for higher end sub-severe wind gusts near
50 mph will be monitored as surface observations indicate gusts in
the mid to upper 30 mph range within the gradient flow which are
expected to peak around 40 mph even outside of convection until
closer to sunset. The front then remains on schedule to sweep
activity eastward followed by surface wind decoupling during early
Low pressure exiting Lake Superior into Canada leaves behind dry
weather and pleasant temperatures in the Great Lakes tonight. Low
temperatures settle only in the 40s once again with the help of
clouds moving in from the Midwest post front to cover any patches of
open sky left over from this evening.
The weak cold front tonight stalls south of the Ohio border by
morning while laying a path for the next low pressure system
Thursday night into Friday. Presentation of the parent upper level
circulation is strong in satellite imagery this afternoon even as it
opens up while being displaced by the incoming Pacific NW jet surge.
This surge of height falls maintains the long wave trough out west
and is now moving into better upper air coverage and potential for
additional refinement in track and intensity of the lead system. The
12Z guidance package does exhibit improved consistency across the
individual deterministic runs, both regional and available hi-res at
the time range, especially the NAM which has fallen much more in
line on track and intensity compared to yesterday. These model
trends add some confidence to a track of the surface low center
roughly from Toledo to Port Huron which feeds into expectations for
QPF and wind. Moisture streaming in from the Gulf coast ensures a
more than adequate supply for model QPF projections in the range of
1 to 2 inches for the 24 hour period from 18Z Thursday to 18Z
Friday. Stripes of locally heavy rainfall occur near the surface low
track where surface based or slightly elevated convection is
maximized, and in the trowal/deformation zone associated with the
upper level trough however without enough separation to spare
concern for any portion of SE MI before the system exits Friday
morning. Assuming the track of the surface low holds, then the best
potential for headline worthy wind gusts also occurs as the system
exits Friday morning. Model soundings indicate easterly flow ahead
of the system dominated by low level stability followed by a very
dynamic NW wind shift Friday morning. This along with the
contributions of low level cold advection defines the time window
for wind gusts in the 40 to 50 mph range, especially closer to the
The low pressure system is on schedule to exit the region Friday
afternoon followed by weak low pressure to start the weekend. Dry
weather and cooler temperatures settle in but highs are still
projected to reach the 50s Saturday afternoon before the next system
moves in by Saturday night. This is more of a northern stream
directed short wave that carries the surface low and bulk of
moisture to our north. Light rain moves out by Sunday followed by
another leg down on temperatures to finish the weekend.
Moderate southwest flow continues into the evening with peak gusts
likely occuring around this forecast issuance. Rain chances will
come to an end by early tonight as the surface low moves across the
upper Great Lakes into northern Ontario. Small craft advisories
continue through the late evening before winds and waves subside as
the low pushes further away from the region. A brief period of quiet
marine weather follows daytime Thursday before the next, stronger
low pressure system tracks into the central and southern Great
Lakes. The low and accompanying rain reaches the southern lakes
Thursday evening before overspreading the rest of the region
Thursday night. An isolated thunderstorm can`t be ruled Friday
night, best chances being over the southern half of Lake Huron south
to Lake Erie. There is some uncertainty in the exact track of this
deep low but looks likely the low center will track over an area
somewhere between the southern portions of Lake Huron to western
Lake Erie. As such, this area has the most uncertainty with winds as
any deviation in track will cause significant changes in wind
speed/direction. Gusts to low-end gales still look possible over the
majority of Lake Huron as strong northerly flow develops behind the
low Friday morning. Air temperatures behind the system do appear
cool enough for a neutral to slightly unstable thermal profile over
the Lake Huron allowing for stronger winds aloft to mix down to the
surface. Gale Watches remain up for daytime Friday.
Scattered to numerous showers and isolated thunderstorms exit
eastward this evening after producing average rainfall less than
0.25 inch. Dry weather overnight and Thursday morning is followed by
a more substantial rain event Thursday night and Friday as a strong
low pressure system moves through Lower Michigan. Scattered
thunderstorms may occur within the broader area of showers Thursday
night. Rainfall totals during this time are expected to reach 1 to
1.5 inches across the area. The rain occurs during a roughly 12 to
18 hour period which limits flooding concerns to prone urban and low
lying areas before the pattern exits Friday morning.
Lake Huron...Gale Warning from 4 AM to 4 PM EDT Friday for LHZ362-363-421-422-
Lake St Clair...Gale Watch from late Thursday night through Friday afternoon for
Michigan waters of Lake Erie...Gale Watch from late Thursday night through Friday afternoon for
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
948 PM CDT Wed Mar 24 2021
Issued at 947 PM CDT Wed Mar 24 2021
Latest surface analysis was showing a front extending from the
Great Lakes southwestward through southern Illinois and southeast
Missouri. Regional radars were showing an area of showers and
thunderstorms across eastern Oklahoma with additional scattered
showers over Kansas into southeastern Nebraska. The area over
eastern Oklahoma was being forced by strong low level moisture
convergence which the RAP has moving northeast into Missouri
overnight. Latest runs of the CAMS are still showing two rounds
of precipitation moving across the CWA over the next 24 hours. One
will be late tonight and early tomorrow with the highest PoPs
over southeast Missouri and southern Illinois and a second on
Thursday afternoon and evening that will be widespread. Latest
runs of the GFS/NAM are keeping the surface low over southeast
Missouri, so there will continue to be some risk for a few severe
thunderstorms over the southern CWA during the afternoon and early
.SHORT TERM... (Through Late Thursday Night)
Issued at 324 PM CDT Wed Mar 24 2021
Stratus and stratocumulus over the northwestern half of the forecast
area this afternoon should continue to gradually retreat northward
through the evening as mixing and entrainment of drier air erodes
its southern extent. The southern extent of this stratus has marked
the approximate location of a stalled southwest to northeast
oriented baroclinic zone. Otherwise, dry conditions should prevail
into the first half of the night. Tonight`s low temps will fall
generally into the 40Fs with light winds and increasing clouds
Late tonight into early Thursday morning, a low-amplitude upper-
level shortwave trough will traverse the region, strengthening mid
to low-level isentropic lift and WAA. These process will aid in
development an early day MCS propagating northeastward immediate
south of the baroclinic zone. Current CAMS indicate the stratiform
region of the MCS could spread into southeastern and east-central MO
and southwestern IL with potentially an isolated thunderstorm.
Following the MCS, rain showers could are expected at times
throughout the day as isentropic lift and WAA continue. During the
second half of Thursday, a more potent upper-level shortwave trough
is progged to lift northeastward across the Midwest as it takes on
an increasingly negative tilt. Strong DCVA associated with the
trough and the left exit region of an upper-level jet streak will
drive another, more widespread round of rain arriving Thursday
afternoon and continuing into the first half of the night. A few
thunderstorms will also be possible with MUCAPE of 250 to 750 J/kg
across southeastern and east-central MO and southwestern IL. Recent
model guidance trends have been to keep the track of the surface low
associated with shortwave trough to the southeast of the forecast
area. This track will favor the warm sector and surface-based
instability, as well as greatest severe threat to the southeast.
Currently the best chance of severe thunderstorms exists to the
south and east of I-44 in MO and I-70 in IL. Despite most
thunderstorms remaining elevated, >60 kt of 0-6 km wind shear and
clockwise low-level curving hodographs will allow them to
potentially become severe. The greatest threat will be large hail
and isolated damaging winds, but a tornado cannot be ruled. Total
QPF through Thursday night will generally range from 0.5 to 1.5"
across the forecast area, with locally higher amounts possible.
These amounts should keep flash flooding concerns low. As with the
severe weather threat, the flash flooding threat will be highest to
the southeast of the forecast area where more widespread
thunderstorms are anticipated.
Rain and thunderstorms should begin to exit the region to the
northeast during the first half of Thursday night. As this occurs,
the surface low will quickly deepen, leading to strengthening
pressure gradient and pronounced pressure rises in its wake. These
conditions will lead to concerns of strong winds late Thursday
evening into night with gusts up to 35 kt possible.
.LONG TERM... (Friday through Next Wednesday)
Issued at 324 PM CDT Wed Mar 24 2021
Following exit of Thursday`s upper-level trough, broad and gradual
upper-level ridging is forecast to dominate the Midwest on Friday,
bringing a return to dry conditions across the region. Low-level
flow will also turn to the south as a low-level ridge axis shifts
east of the area, allowing temps on Friday to warm to above average
with increasing WAA.
On Saturday, a longwave upper-level trough is expected to traverse
the northern-half of the central U.S. This evolution will resulting
in formation of a weak surface low in the Central Plains that will
track into the Midwest along with its attendant cold front during
early Saturday morning into Saturday night. These features could
provide the next opportunity for rain across the region. However,
weak lift inherent from the diffuse nature of the cold front and
DCVA associated with the trough combined with only modest Gulf of
Mexico moisture return will likely limit rain shower coverage and
rainfall amounts. This notion is supported by a number of GEFS and
EPS members even keeping the forecast area completely dry. Despite
modest available moisture, steep mid-level lapse rates could yield
instability sufficient for a few thunderstorms as well. A severe
thunderstorm cannot be discounted with strong vertical wind shear
expected to be in place. Saturday may also be the warmest day of the
extend period with pre-frontal WAA boosting 850-hPa temps to as high
as 12C, translating to high temps 10 to 15F above average.
Global model guidance are in general agreement that upper-level
riding will briefly dominate the area Sunday before disparities grow
with potential ejection of an upper-level cutoff low from the Desert
Southwest into the Central Plains ahead of an upper-level trough
reaching the western U.S. Although some rain could be possible with
passage of the cutoff low across the Midwest, the majority of GEFS
and EPS members portray the best chances for precip during the
middle of next week will be tied to arrival of the trough. After
near average temps Sunday, temps will also moderate to above average
ahead of the trough by the middle of next week.
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 601 PM CDT Wed Mar 24 2021
Dry and VFR conditions are expected this evening before scattered
showers moves into central and east central Missouri overnight and
southwest Illinois overnight into Thursday morning. A more
widespread round of showers and scattered thunderstorms will move
into the terminals on Thursday afternoon. Visibilities and
ceilings will drop to low MVFR/possible IFR at times on Thursday
SPECIFICS FOR KSTL:
Dry weather is expected through at least 11Z before scattered
showers and possible thunderstorms move into the terminals early
Thursday. Do not have enough confidence in this threat to have any
more than VCSH at this time. A more widespread round of showers
and thunderstorms will occur on Thursday afternoon and evening, so
have gone with showers starting at 18Z with IFR visibilities
during the late afternoon into the evening. These showers will
likely move out during the evening hours.
Area Forecast Discussion
National Weather Service Melbourne FL
915 PM EDT Wed Mar 24 2021
Light SSE-S flow continues along the western flank of a large high
pressure ridge centered over the western Atlantic. A large swath of
leftover convective debris currently streaming over the northern 2/3
CWA is thinning out, and will continue to do so overnight, leaving
mostly clear skies areawide. Given the prevailing light BLYR flow is
from the south, expect any overnight fog to be more patchy/shallow
in nature. While the latest HRRR run shows fairly widespread/dense
fog, it busted pretty hard showing the same thing taking place last
night. Mild overnight low in the L60s expected for all but the
Treasure Coast (M-U60s).
.AVIATION...VFR. Late night fog should be patchy and quite shallow,
thus opted to run with TEMPO MIFG in that area, probably no worse
.MARINE...Latest local buoy obs show moderate NE swells continuing
to subside, now down to 3-4ft. This should continue overnight with
light SE to SSE flow freshening just a bit to around 10-12kt.
.PREV DISCUSSION... /issued 402 PM EDT Wed Mar 24 2021/
Thursday...High pressure conditions will extend from the surface to
the upper levels of the atmosphere as a high pressure builds near
the local area. No rainfall in the forecast and temperatures will
really climb, reaching the lower 90s west of I-95, with locations
near the coast capping to the mid 80s. High records were included
below under the Climate section. Winds will be from the south in the
morning, with a southeast shift in the afternoon due to a sea breeze
Late week-weekend... Surface high pressure will continue to build
over the western Atlantic. A mid and upper level ridge with a center
over the Bahamas will stretch into Florida and the western Atlantic
waters through the weekend. The location of the high will keep the
region in southerly flow with a loose gradient. The strong high will
keep conditions dry but hot and muggy. High temperatures will reach
the mid-to-upper 80s across the coast and into the lower 90s across
inland locations with dew-points in the mid-to-upper 60s. Record
heat is possible through the weekend - mostly over inland locations.
Lows will only drop down into the mid 60s to around 70 degrees.
Next week... The ridge over the southeast will flatten slightly as a
trough moves through the mid and deep south. This will bring
northerly flow and slightly cooler temperatures to the Space Coast
to start off the workweek. However, the area should remain mostly
dry with chances of rain at this time not high enough to introduce
into the long term forecast this far out. Temperatures will drop
into the upper 70s to low 80s across the coast for highs with mid
80s expected for highs across areas further inland. Lows will mostly
remain in the 60s through the overnight hours.
VFR conditions through tonight. Fog is forecast to develop late
tonight into Thu morning, which could reduce visibilities. A few
Tempos were added, for KDAB to KMCO to reflect this but it could
be needed southward if fog develops closer to the coast.
Otherwise, light winds through Thu morning, increasing to 10-15 kt
from the south.
Tonight-Thu...A ridge will approach the local waters tonight and
Thu, which will lead to more favorable conditions over the
Atlantic waters through the end of the week. Swell component will
slowly subside with seas of 3-4 ft on Thursday lowering to around
3 ft Friday through Saturday and 2-3 ft Sunday through Monday.
Winds will generally be out of the south-southeast with an
afternoon wind increase over the Intracoastal and open marine
Extended...High pressure will remain over the area through the
start of next week. However, an upper-level trough will track
through the mid and deep south which will cause the ridge over the
far southeastern CONUS and Bahamas to relax. Winds will switch on
Tuesday from the east-northeast at 10-15 kt with gusts to around
23kts causing seas to build up to 5-7 feet in the Volusia and
northern Brevard counties offshore waters
Southerly flow around high pressure centered over the Atlantic
will keep a warming trend in place through the end of the week
for east central Florida. No mentionable rainfall chances are
expected at least through the first part of next week. Dispersion
is improving on Thursday but minimum RH will be dropping to near
35 percent across the interior. A Fire Weather Watch was issued
for Thursday afternoon for the interior counties as conditions
will reach the borderline of our local thresholds. ERC values
are above 27 and should be increasing in the next few days.
The 20 feet winds will be just below criteria.
List of high records for Thursday, Mar 25 and Friday, Mar 26 across
east central Florida and the year they last occurred.
Site Thu Fri
Daytona Beach 88(1954) 89(1944)
Leesburg 88(1975) 87(2020)
Sanford 91(1949) 90(2002)
Orlando 95(1929) 94(1929)
Melbourne 92(1975) 90(1975)
Vero Beach 91(2020) 88(2015)
Fort Pierce 91(2020) 91(1935)
River levels on the St. Johns around Astor are forecast to remain
near Action Stage of 2.0 feet through the next few days, before
levels gradually decrease from the late weekend into next week.
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 86 64 88 / 0 0 0 0
MCO 63 91 67 92 / 0 0 0 0
MLB 65 86 68 87 / 0 0 0 0
VRB 64 87 68 87 / 0 0 0 0
LEE 63 91 65 92 / 0 0 0 0
SFB 64 90 65 91 / 0 0 0 0
ORL 66 91 67 92 / 0 0 0 0
FPR 64 87 66 88 / 0 0 0 0
FL...Fire Weather Watch from Thursday afternoon through Thursday
evening for Northern Lake-Okeechobee-Orange-Osceola-
Area Forecast Discussion
National Weather Service San Angelo TX
628 PM CDT Wed Mar 24 2021
(This evening through Thursday)
Issued at 249 PM CDT Wed Mar 24 2021
Early this afternoon, a stationary front was located west to east
along a Big Spring, San Angelo to Brady line. A dryline was also
situated across our southwestern counties and was just east of Ozona
as of 2 PM. The airmass south of the front and east of the dryline
was beginning to destabilize over our southeast counties, with
surface based CAPES 1000-1500 J/kg noted between Sonora, Junction
and San Saba per latest SPC mesoanalysis. Visible satellite imagery
shows enhanced cumulus developing over this area the past couple of
hours. Latest HRRR is showing some convective development around
21Z, while some of the other models were less aggressive. If storms
manage to develop, large hail and damaging winds will be a concern,
given the moderately unstable airmass and deep layer shear between
50 and 60 knots.
More widespread showers and thunderstorms are expected to develop
later this evening, as lift increases with an approaching upper
trough to our west. Additional strong to severe storms will be
possible from late evening into the overnight hours, with the severe
threat confined to far southeast counties. The main threat again
will be large hail and damaging winds. A cold front will move south
across the area overnight, with precipitation ending across eastern
counties late. Dry and pleasant weather is expected on Thursday,
with highs in the upper 60s and lower 70s.
(Thursday night through next Wednesday)
Issued at 249 PM CDT Wed Mar 24 2021
Gusty south to southwest return Friday as lee trough in West
Texas strengthens. It will be warmer with highs in the lower 80s.
A cold front will be moving through Saturday afternoon.
Temperatures will still be seasonably warm with upper 70s in the
Big Country and with lower 80s south.
Low level moisture will begin flowing over cooler air at the
surface Saturday night...as an upper trough approaches from the
West. Can`t rule out isolated showers Saturday night, but the
best potential for showers and thunderstorms will be Sunday into
Monday night. Showers taper off Monday afternoon...as the upper
trough/low moves east of the region. It`s a little early to
determine severe potential but southern sections along I-10 to
Mason and Saba are only marginally unstable in the GFS model with
MUCAPES of around 500 J/KG Sunday and Sunday night. This could
still change, however, as moisture is one of the more difficult
things for the models to predict.
Issued at 623 PM CDT Wed Mar 24 2021
Isolated convection continues to develop early this evening, but
nothing very close to a terminal location. More widespread
convection is still expected to develop farther north and west and
much closer to terminal locations later this evening and into the
early morning hours. Shortlived MVFR conditions possible with
these storms. This will push east of the area and leave drier
conditions by sunrise Thursday morning. Otherwise, decreasing
cloud cover for Thursday with west to northwest winds at around 10
.PRELIMINARY POINT TEMPS/POPS...
Abilene 43 68 48 80 / 40 5 0 0
San Angelo 43 71 47 82 / 40 0 0 0
Junction 45 74 46 84 / 60 0 0 0
Brownwood 45 70 46 81 / 60 5 0 0
Sweetwater 42 68 49 79 / 20 0 0 0
Ozona 44 71 48 81 / 30 0 0 0