Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/30/23
Area Forecast Discussion
National Weather Service Columbia SC
741 PM EDT Sat Apr 29 2023
.SYNOPSIS...
A strong low pressure system deepens as it moves towards the
area from the Gulf Coast region tonight into Sunday, bringing
periods of rainfall to the area. Dry conditions and cooler than
normal temperatures expected early next week as troughing
dominates the weather over the eastern CONUS.
&&
.NEAR TERM /THROUGH TONIGHT/...
Strong upper shortwave currently moving through the Lower
Mississippi Valley, ahead of which some upper energy currently
approaching our region in a SW flow aloft, leading to moisture
increase and a batch of showers and some thunderstorms currently
approaching our FA from the SW. This activity will move NE into
the W FA this evening, and across the remainder of the FA later
tonight. A surface low is progged to develop over the N GOMEX
and track NE into our FA late tonight, leading to some
additional precipitation affecting our FA late tonight into
early Sunday. Limited instability but significant shear leads to
some severe weather concerns. The southern half of our FA is
outlooked in a MRGL risk of severe weather per latest SPC Day 1
outlook.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
Sunday: Activity associated with the aforementioned cold front
should be ongoing as day breaks. The limited severe threat
shifts to the northern half of the forecast area, particularly
the northeastern portions for the mid morning hours as the cold
front progresses northeastward. A third round of precipitation
associated with the passage of the upper low is expected for
midday into the afternoon. Activity with the upper low passage
could also produce some stronger storms, with damaging wind and
large hail being the main threats. Like with the earlier morning
activity, confidence is low in any severe weather occurring.
Behind the outgoing system, gusty west to southwest winds are
expected to develop. Winds are anticipated to gust to 25 to 30
mph at times from mid morning into the evening, which has
prompted a Lake Wind Advisory.
Sunday night: Cold advection will spread over the region Sunday
night in the wake of the departing upper trough. High pressure will
build in from the west as another expansive closed upper low
establishes itself over the eastern Great Lakes and Ohio Valley
region. Much drier air will move into the region with PWATs falling
below a half inch. Winds should remain breezy through the evening
with a bit of a pressure gradient and deep mixing with strong low
level westerly winds. Despite clearing skies the mixed boundary
layer with winds staying up should limit radiational cooling
but cold advection looks to support lows in the upper 40s to
lower 50s.
Monday through Tuesday night: Sensible weather should be relatively
benign this period with a continued dry and stable air mass in
place. Ensemble guidance continues to show a persistent upper closed
low over the eastern part of the country with PWATs remaining below
a half inch, so no precipitation is expected.
Winds will be the main concern both Monday and Tuesday during the
day as 850mb winds will be from the west around 35-40 knots and with
deep mixing expected each day, breezy conditions are expected.
Surface winds should be 15 to 20 mph with gusts as high as 35 mph
both days and a lake wind advisory may be needed. Depending on total
rainfall through the weekend, there could be some fire weather
concerns developing by Tuesday due to significant dry air and breezy
conditions if fuel moisture lowers enough.
Below normal temperatures expected this period with highs ranging
from the upper 60s to mid 70s and lows in the 40s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Ensemble and deterministic guidance in reasonable agreement with
the overall pattern. A shortwave will round the base of the
lingering upper low over the eastern part of the country pushing a
dry reinforcing front through the region late Tuesday night and
Wednesday morning. The upper low will then shift eastward off the
New England coast as flat upper ridging occurs over the Plains
states allowing some shortwave energy to move into the region in
northwesterly flow aloft by Friday into Saturday, bringing an
increase in chances of rain. Dry weather is expected Wednesday and
Thursday with cooler than normal temperatures on Wednesday and
moderating temperatures back closer to normal on Thursday with
continued warming on Friday. No significant weather expected at
this time.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR into this evening before IFR becomes likely overnight.
Regional radars showing area of rainfall just south of the CSRA
terminals of ags/dnl at issuance time. This is right in line
with the latest hrrr and near term models for the most part.
Guidance consistent with bringing rainfall northward and near
cae/cub/ogb by 01z, with the rain then overspreading all taf
locations through 06-07z. Some rumbles of thunder possible along
with the rain, so mentioned cb when the heavier more persistent
rainfall moves into the area. After 07z, there may be a break
overnight in the rainfall, with another batch then moving in
closer to 12z. Drier air not expected to really move until early
Sunday afternoon.
Until then, plenty of cloud cover will remain. Conditions start
off vfr, then do drop down to mvfr after 07z when the first
batch of rain moves out. A continued lowering to ifr will be
possible towards 12z with the next round of rainfall. A return
to vfr conditions should occur by 19z at all locations as drier
air moves in and winds increase mixing.
In addition to the rain and clouds, can not completely rule out
low-level wind shear towards daybreak. Due to low confidence
though, will not include at this time. As the activity begins
to wind down on Sunday, west to southwest winds gusting to 20
to 25 kts become likely.
EXTENDED AVIATION OUTLOOK...Sunday night, dry air begins to
limit chances for restrictions lasting through the end of the
forecast period with the exception of early morning fog at OGB
and AGS.
&&
.HYDROLOGY...
Runoff from recent widespread heavy rain, with totals around 3
to 5 inches, Wednesday through Thursday night, across the
Upstate and Piedmont of SC, and the Foothills and Western
Piedmont of NC, will continue to flow downstream and provide
river flooding at several forecast points along the Enoree,
Saluda, and Congaree Rivers. Details available on our website.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Lake Wind Advisory from 8 AM to 8 PM EDT Sunday for GAZ040-
063>065-077.
SC...Lake Wind Advisory from 8 AM to 8 PM EDT Sunday for SCZ016-018-
020>022-025>031-035-037-038-041-115-116-135>137.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
926 PM EDT Sat Apr 29 2023
.Forecast Update...
Issued at 926 PM EDT Sat Apr 29 2023
- Chance for showers overnight.
- Cool
Surface analysis late this evening shows deep low pressure over the
UP of Michigan. From this low, a cold front extended southeast
across MI and then southwest across Northern Indiana to Central IA.
An area of showers and clouds was found in the wake of the front
over IL and NE MO. Cyclonic flow remained across Central Indiana.
GOES16 shows waves of clouds, some of which have showers,
pinwheeling around the nearby upper low. Cool westerly surface flow
was in place across Central Indiana, with temperatures in the 50s.
Stronger NW flow with a tighter pressure gradient was found in the
wake of the cold front over IA and WI.
Tonight the upper low is expected to sag southward across MI,
keeping cyclonic flow in pace across central Indiana. This flow will
aid the progression of the cold front across Central Indiana, as it
will pass across the forecast area during the overnight. Rain
showers and cloud cover associated with the cold front, as seen over
western IL, are expected to pass across the forecast area in the
wake of the cold front. HRRR is on board with this, showing showers
moving across the area. Forecast soundings and time heights also are
on board, showing lower level saturation as these features pass.
Thus will aim for some chance pops for light precipitation as the
cold front passes. Precipitation amounts should be light, with the
best coverage in place across the northern half of the forecast
area. Given the temps in the wake of the cold front, lows in the
lower to middle 40s will be on the mark.
&&
.Short Term...(This evening through Sunday)
Issued at 248 PM EDT Sat Apr 29 2023
As of this afternoon, a large trough is diving down out of Canada
and is expected to be the primary factor determining our weather for
the next few days. At the surface, southwesterly flow ahead of this
feature has allowed temperatures to warm up to near 70. That will be
short-lived, unfortunately, as a cold front associated with the
trough advances southward.
Showers and thunderstorms are possible today, primarily focused near
and along the front. Very steep low-level lapse rates and sufficient
moisture should allow enough instability for a few thunderstorms
capable of briefly gusty winds. Severe thunderstorms are not
expected, though a few gusts to 45mph are certainly possible. Any
lingering shower or storm should come to an end as the front exits
into Ohio.
Behind the front, winds become northwesterly and cold air advection
takes hold. Temperatures within the core of the upper-level low are
expected to be rather chilly, roughly between 0C and -5C for the
next few days. As such, expect cooler than normal weather through
tomorrow. Lows tonight should dip into the low 40s and rebound into
the low to mid 50s tomorrow before rapid stratocumulus development.
A vort max rotating around the trough should swing through tonight,
bringing a secondary round of showers. Instability is very limited,
so not expecting thunder with this. Thunder chances return after
sunrise, however, as diurnal heating generates modest amounts of
CAPE given the very cold air mass aloft. Thermal profiles suggest
that graupel or small hail may be possible within some of the
stronger showers or storms. Additionally, steepening lapse rates
should allow efficient downward momentum transfer tomorrow, leading
to wind gusts reaching 25 to 30kts at times.
&&
.Long Term...(Sunday night through Saturday)
Issued at 248 PM EDT Sat Apr 29 2023
The beginning of the long term will be heavily influenced by a
nearly cutoff upper level low, of which will remain within the
perifery of Indiana through Tuesday. Synoptically, an Omega Block
pattern will set up over the CONUS, reinforcing ridging over the
Mountain-West. This will elongate and stetch upper level troughing
east of the Mississippi River leading to below seasonal temperatures
for much of this area.
Central Indiana will origonally be within a martime polar-like air
mass as moisture wraps around the stagnant low. This should lead to
cool, semi-wet conditions. Forcing will be marginal, but sporatic
light showers within low cloud cover are likely Monday and Tuesday.
Prolonged cloud cover will limit diuranl temperature swings, keeping
surface temperatures between the upper 30s and mid 50s, witfh a
few SW locations in the upper 50s.
By Tuesday night, slight progression of the ridge will allow for a
drier airmass to advect over the region. This should allow for skies
to clear sometime Tuesday night, leading to more effeceint diurnal
cooling and colder temperatures Tuesday night into Wednesday f
morning. Freezing temperatures Wednesday morning will be possible.
Winds will be fairly strong within a fairly steep pressure
gradientf over the area, although a suppressed PBL should limit
gusts slightly.
The second half of the week should slightly warmer as the ridge
begins to influence the Great Lakes Region. Temperatures will still
be slightly below seasonal within NW flow, but the mostly dry air
mass will create near dry adiabatic PBLs within high downwelling SR
of early May. Isolated showers are possible Friday into Saturday
associated with a weak low level disturbance. Expect highs in the
mid to upper 60s with overnight lows closer to the dew point in the
upper 30s and low 40s Wednesday through Saturday.
.
&&
.Aviation...(00Z TAF Issuance)
Issued at 701 PM EDT Sat Apr 29 2023
Impacts:
* Waves of showers with isolated thunderstorms tonight and again
Sunday afternoon.
* Mainly VFR conditions tonight with MVFR conditions Sunday.
* Gusty winds around 25kts on Sunday.
Discussion:
Radar shows and area of convective showers pushing to the southeast
of the Taf sites. These showers are expected to end/exit within the
first few hours of the TAF period due to the loss of daytime heating
and propagation.
Broad cyclonic flow will remain across the TAF sites through this
TAF period due to the deep upper low found over WI. This feature is
expected to remain across the Great Lakes through the TAF period,
allowing waves of upper support to pinwheel across the TAF sites
within the next 24-36 hours. Models suggest a wave pushing through
overnight. Precipitation over IA at the moment is associated with
this wave. We have included a period of VCSH overnight with low VFR
cigs as this passes. In the wake of this system MVFR Cigs are
expected to arrive on Sunday, with another wave suggested to pass on
Sunday afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Puma
Short Term...Eckhoff
Long Term...Updike
Aviation...Puma
Area Forecast Discussion
National Weather Service North Platte NE
1047 PM CDT Sat Apr 29 2023
...Aviation Update...
.SYNOPSIS...
Issued at 236 PM CDT Sat Apr 29 2023
Key Messages:
Key Messages in short term:
*Critical fire weather concerns continue this afternoon and tomorrow
*Gusty winds remainder of this afternoon and north central NE Sunday
Key Messages in the long term:
*Above normal temperatures Wed. and Thu.
*Elevated to near critical fire weather concerns through mid-week
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 236 PM CDT Sat Apr 29 2023
Did do some minor tweaks to the rest of the afternoon
forecast. Adjusted temperatures a few degrees warmer and
increased winds slightly across the south where felt there could
be some better mixing through early evening that would mix down
some stronger gust.
For Sunday, did trend winds toward the 90 percentile to blend
more closely with the RAP and NAM models, mainly across southwest
into north central Nebraska, where there was a slight increase.
Don`t expect to see the amount of mixing or the strong winds
aloft, as seen today, however it will still remain fairly breezy
across north central Nebraska back into portions of southwest
Nebraska, with the potential for gust of 35 mph or greater.
The cooler air mass behind the front will keep temperatures
cooler on Sunday with highs in the mid 50s to low 60s, which is
below normal. Despite the cooler temperatures Sunday there is
still the potential for near-critical to critical fire weather
concerns, see fire weather discussion below for additional
information.
.LONG TERM...(Monday through Saturday)
Issued at 236 PM CDT Sat Apr 29 2023
The High Plains will continue to see a upper level
northwest flow as they are wedged in between a strong upper level
low to the east across the Great Lakes Region and a ridge to the
west across the Rockies into the Canadian Prairie for the
beginning of the week. As the upper level low across the Great
Lakes continues to move eastward, the ridge to the west begins to
expand east into the High Plains region, with temperatures
reaching the 70s by Tue. and 80s by Wed. Temperatures will remain
above normal for Thursday as well with highs in the mid to upper
70s. The airmass on Tuesday and Wednesday and even into Thursday
will be fairly dry and thus will present some elevated to near-
critical fire weather concerns for those days, will need to
continue to monitor.
A weak disturbance may move through Wed. night into Thu. bringing
the potential for some light showers. However, although there
will be some return flow of moisture with the system, would not
expect any wetting rains, but could see some spotty light rain
showers, at this time confidence is low to see much coverage in
precip. There will be another potential for precip towards the end
of the period as the upper level low spinning across the west
coast earlier in the week finally moves ashore and into the
central CONUS, again though, confidence is low at this time in the
way of precip coverage for the area, but spotty showers may be
possible.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1046 PM CDT Sat Apr 29 2023
VFR conditions will continue to prevail the rest of tonight and
through the day Sunday. Winds will go down some tonight but then
pick up again from the north to northwest Sunday. Gusts Sunday
afternoon will again be in the 25-35 kt range.
&&
.FIRE WEATHER...
Issued at 236 PM CDT Sat Apr 29 2023
The combination of strong winds, warm temperatures and low humidity
will result in the near-critical to critical fire weather concerns
to continue through the remainder of this afternoon into the
early evening. For the overnight hours, the recovery will be poor
across western and southwest Nebraska where overnight humidity
values will range from 55% to 65% percent. This will then result
in setting up another day of critical fire weather concerns with
the combination of poor overnight recovery, low min RH and gusty
winds for Sunday afternoon and early evening. Critical fire
weather concerns will generally be across fire weather zone 219,
with near-critical concerns across fire weather zones 210 and 209.
A Red Flag warning has been issued for Sunday, for fire weather
zone 219, as confidence is greatest for this zone to meet RFW
criteria. Winds in this area will be around 20 mph or more out of
the north northwest, with gust up to 30 mph, in combination of low
RH values as low as 14 percent.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 1 PM to 8 PM CDT Sunday for NEZ219.
&&
$$
SYNOPSIS...Gomez
SHORT TERM...Gomez
LONG TERM...Gomez
AVIATION...Taylor
FIRE WEATHER...Gomez
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1005 PM EDT Sat Apr 29 2023
.SYNOPSIS...
High pressure will briefly build into the area today bringing
quieter conditions to the region before another strong and wet
storm system moves up the East Coast Sunday into Monday. Drier
and cooler weather is then expected through mid next week as
high pressure builds into the Eastern CONUS.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 8:15 PM Saturday...All is quiet across the FA with CAMs in
agreement for the first round of convection to start in our
southern counties and offshore waters between 3-6Z. The 00Z
sounding shows impressive values of CAPE, shear, and SRH. Near
the time of convective initiation, RAP analysis shows 500-1000
J/kg of MLCAPE, 45-50 kts of effective bulk shear, and SRH
values around 100 m2/s2. These conditions could be favorable for
supercells and/or organized convection with strong updrafts
through the early morning hours. The potential for isolated
tornadoes, damaging wind gusts, hail, and heavy rain are all on
the table.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
As of 10 PM Saturday...Only minor tweaks to lower the PoPs
behind the first round of showers and thunderstorms. As stated
in the previous discussion, this could allow instability to
rebuild for the second round of potentially severe storms tomorrow
afternoon.
Previous Discussion...As of 1630 Saturday...Vigorous shortwave
becomes negatively tilted while pivoting around broad cyclonic
flow over the eastern CONUS, driving rapid surface cyclogenesis
over the Carolinas and mid- Atlantic on Sunday posing multiple
hazards. Heavy rain and thunderstorms, particularly over the
Outer Banks, will be ongoing tomorrow morning as the surface low
lifts along the I-95 corridor. Widespread model consensus shows
showers and tstorms likely ongoing during the morning,
especially in the vicinity of the surface low as it lifts north.
It is during this period that severe potential will be
maximized as surface CAPEs surge north of 1000 J/kg, coupled
with effective shear of 40-60 kts thanks to stout 850mb and
500mb jets. This will also be the most favorable time for
potential tornado development with any discrete cells. SPC has
our area in a Slight Risk of severe thunderstorms with an
isolated tornado and damaging winds being the main threat. Have
lowered PoPs behind this initial wave of precip when some
clearing is possible, which would allow instability to rebuild
for the next round of convection in the afternoon and evening.
The next wave of convection, driven by the cold front behind the
low, is expected to cross the region from west to east during
mid- afternoon. Some instability will likely linger across the
region despite considerable atmospheric turnover with the
morning low, and a few strong thunderstorms are again possible.
By this time, low- level wind profiles will be more
unidirectional favoring damaging winds as the primary hazard but
there will be a nonzero threat for an isolated tornado or hail
should the stronger instability and cooler air aloft be
realized.
Outside of convection, a brief but potent surge of south to
southwesterly winds is expected, especially in the afternoon as
the low lifts north. Gusts pushing 40+ mph are probable across
portions of the Outer Banks. The surge, while brief, could lead
to some minor soundside flooding issues north of Cape Hatteras.
A coastal flood advisory has been issued for these areas. See
the TIDES/COASTAL FLOODING section for details.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 1645 Sat...The low that impacted the area SUnday occludes
and lingers over the Great Lakes for the first half of the work
week before high pressure eventually wrestles back control,
leaving eastern North Carolina cooler and drier for the
remainder of the period.
Monday through Friday...Primarily dry and cooler than average
conditions hold over eastern North Carolina through the rest of
the period as the surface low occludes over the Great Lakes and
meanders over the region through Wednesday. While the low stays
in place, healthy southwest to westerly winds are expected
during the afternoons with gusts up to 25 kt. The strongest
winds are likely on Tuesday ahead of a surface trough pivoting
around the low, with gusts to 25-30 kt possible over the coastal
plain. When coupled with much lower dew points in the upper 30s
to low 40s, RHs will fall well into the 30% range raising fire
weather concerns.
By Thursday, the surface low will have lifted out over the North
Atlantic allowing high pressure to take more dominant control,
quickly shifting offshore and aiding in moist southerly return
flow. By the end of the week, temperatures will have rebounded
to seasonal norms after days of being 5-10 degrees below
average. The next system to watch will be at the end of the week
as weak low pressure zips along a stalled front. Typical model
differences preclude mentionable PoPs in the forecast for this
cycle.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /through 00Z Monday/...
As of 8:15 PM Saturday...All TAF sites expected to remain at
VFR until showers and thunderstorms start to develop near 06Z
causing a drop to MVFR CIGs. During heavier rain, some
visibilities could briefly drop to MVFR/IFR. A second round of
rain and thunderstorms is expected tomorrow afternoon along with
gustier SW winds around 25 kts.
LONG TERM /Sunday through Wednesday/...
As of 400 AM Sat...Low pressure continues to lift across the
area tomorrow bringing multiple waves of showers and
thunderstorms and extended periods of sub-VFR conditions. A few
strong thunderstorms are possible particularly in the morning
and early afternoon. By late Monday, the low departs with VFR
conditions returning and remaining dominant for the rest of the
period.
&&
.MARINE...
SHORT TERM /through Tonight/...
As of 1645 Saturday...High pressure resides over the waters
through this evening before a strong area of low pressure
approaches the waters from the SW late tonight and produce
strong winds, building seas, and tstorms.
Light and variable winds, predominantly out of the SE currently
become SSEerly 10-15 kt through this evening with seas generally
subsiding through the evening, 5-6ft N of Ocracoke Inlet, 4-5 S.
SCAs in place for linger 6ft seas continue stepping down, Nern
waters 0Z, Central waters 6Z. As strong low pressure approaches
late tonight Serly winds over the Sern and Central waters will
increase to 15-25 kt with seas rebuilding to 5-7 ft 9-12Z
Sunday, kicking off an extensive period of hazardous marine
conditions, particularly for coastal waters. Strong low pressure
will continue to lift across the region tomorrow afternoon with
a surge of Serly to SWerly winds. Sustained winds of up to
30-35 kt are expected with gusts as high as 40 kts at times.
Within passing showers and thunderstorms, higher winds are
possible. This will rapidly build seas, up to 10-13 ft for
Raleigh Bay and outer Onslow Bay by sunset on Sunday. North of
Cape Hatteras, seas of 8-11 feet are anticipated particularly
beyond 10-15 nm.
Existing Gale Watches have been upgraded to Gale Warnings and
SCAs have been issued for all remaining inland waters.
LONG TERM /Sunday through Wednesday/...
As of 1645 Sat...Persistent SCA winds will continue at least
through Wednesday as the surface low lingers over the Great
Lakes keeping the pressure gradient tight over the waters.
Beyond tomorrow, the strongest winds are expected on Tuesday
ahead of an approaching coastal trough with southwesterly winds
gusting up to 30 kt. This will keep seas up to 6-8 feet
particularly south of Oregon Inlet, through Wednesday afternoon.
&&
.FIRE WEATHER...
As of 1700 Saturday...Behind strong low pressure system Monday
morning, cooler and drier high pressure will move into the area
through most of next week. While this occurs, a large and
occluded low pressure system will sit over SE Canada, and keep a
strong pressure gradient intact across the Carolinas through
Wednesday.
RH values will drop to at least 30%-35% each afternoon, while
winds remain strong at 15-20 mph with gusts 25-30 mph. The
strongest winds are expected Tuesday afternoon ahead of a
surface trough pivoting around the parent low. Deep mixing may
promote even stronger wind gusts at times.
&&
.TIDES/COASTAL FLOODING...
As of 1700 Saturday...A brief but potent surge of southerly to
southwesterly winds is expected late Sunday morning into the
afternoon as strong low pressure lifts across the coastal plain.
Gusts could reach as high as 40 mph particularly along the
Outer Banks. Despite the short duration of the winds, some minor
soundside flooding of 1 to 2 feet is possible with the most
vulnerable areas being the Outer Banks north of Cape Hatteras.
Coastal Flood Advisories have been issued for these areas.
In addition to flooding, dangerous surf conditions are likely to
develop on Sunday and linger into Monday. The most vulnerable
beaches will be Sern facing beaches, predominantly from Cape
Hatteras south, and could lead to overwash and dune erosion.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement through Sunday evening for NCZ195-196-
199-203>205.
Coastal Flood Advisory from 8 AM to 10 PM EDT Sunday for
NCZ195-196-199.
High Surf Advisory from 11 AM Sunday to 5 AM EDT Monday for
NCZ195-196-199-204-205.
Coastal Flood Advisory from 11 AM Sunday to 2 AM EDT Monday
for NCZ203-205.
MARINE...Small Craft Advisory from 11 AM Sunday to 7 AM EDT Monday for
AMZ131-230.
Gale Warning from 2 PM to 8 PM EDT Sunday for AMZ135.
Small Craft Advisory from 8 AM to 8 PM EDT Sunday for AMZ136-
137-231.
Small Craft Advisory from 9 AM Sunday to 10 AM EDT Monday for
AMZ150.
Small Craft Advisory until 2 AM EDT Sunday for AMZ152-154.
Gale Warning from 10 AM to 10 PM EDT Sunday for AMZ152-154.
Gale Warning from 10 AM to 9 PM EDT Sunday for AMZ156-158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...CEB/OJC
SHORT TERM...MS/CEB/OJC
LONG TERM...SGK/MS
AVIATION...CEB/OJC
MARINE...MS/CEB
FIRE WEATHER...MHX
TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1057 PM CDT Sat Apr 29 2023
.DISCUSSION...(This evening through Saturday)
Issued at 254 PM CDT Sat Apr 29 2023
KEY MESSAGES:
- Rain is expected to change over to snow overnight in western WI,
with minor accumulations on grassy and elevated surfaces possible.
- Strong northwest winds, with gusts to between 40 mph and 50 mph
will be possible Sunday west of the Mississippi River.
- Next week continues to look dry and mild, with highs in the 70s
possible west of the Mississippi River on Wednesday.
While stratiform cloud cover and light rain continue to plague
portions of western WI, clearing to the west has allowed a cumulus
field to develop in MN. Radar imagery shows scattered diurnal
showers present within this cumulus field that will move south-
southeast as the afternoon progresses. Only the central portion of
MN is shower-free where the stronger subsidence that was mentioned
in this morning`s discussion has been realized. Thus, expect
scattered showers into this evening basically everywhere aside from
central to southeastern MN. CAMs forecast these showers dying off
this evening with the loss of daytime heating.
Our pesky low pressure system will continue to spin over the Upper
Great Lakes through Sunday and, just when you think it couldn`t get
any more annoying, deepen. Another jetstreak will round the base of
the trough and the accompanying lift ahead of it will allow for mass
evacuation within the low. This will do 2 things:
1. Wrap-around precip to the west of the surface low (eastern MN and
WI) will restrengthen tonight and persist through most of Sunday.
While surface temperatures will be above freezing tonight (mid 30s),
very cool thermal profiles should allow for snow to mix in the
eventual rain. This is most likely as one heads farther east into
central WI where the coldest air will reside. Here, 1 to 2 to
perhaps up to 3 inches of snow may accumulate on elevated on grassy
surfaces by Sunday morning. Snowflakes will be less likely into
eastern MN but cannot rule out a flake or two as winter`s last gasp
occurs. Precip should change over to all rain and slowly trudge east
as Sunday`s temperatures warm into the mid to upper 40s.
2. Northwesterly winds will greatly increase due to the
strengthening pressure gradient. Sustained surface winds on Sunday
will be at least 20 knots across the entire region with strongest
winds in western MN (25-30 knots). With gusts at least another 10
knots on top of sustained values, a Wind Advisory may be needed for
portions of MN Sunday. One possible complication is that RAP
forecast soundings show maximum boundary layer lapse rates
(strongest daytime heating) don`t coincide with the timing of the
strongest LLJ. Thus, winds may not reach their full potential.
Chances for rain showers (mixing in with some snow) continue Monday
night in western WI as lows fall to the low to mid 30s area-wide.
Monday`s weather will be similar to Sunday`s, albeit with shower
chances slightly farther east, highs warmer in the upper 40s to mid
50s (warmest west), and winds slightly weaker. We should finally be
rid of the low pressure system by Tuesday with a warm up towards
more seasonable temperatures following. Guidance suggests Wednesday
will be the warmest day with highs exceeding 70 for most of MN. For
the rest of the period, highs should generally be in the upper 50s
to mid 60s and lows in the 40s.
As for precipitation, NBM PoPs are very low the remainder of the
period as a rex block pattern unfolds. Blocked ridging over the
central CONUS and Canada should keep any strong synoptic systems
from encroaching the Northern Plains. Thus, any precipitation will
likely have to come from small-scale features which tend model
predictability tends to degrade greatly with in respect to time.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1057 PM CDT Sat Apr 29 2023
Light snow will has developed over northeast WI and will build
southwestward overnight to EAU by 08Z, RNH by 09Z, and possibly MSP
by 11Z. Biggest impact will be to visibilities which could drop to
IFR levels. Strong northwest winds will develop late tonight and
early Sunday morning with gusts of 35-43 kts expected west of the
Mississippi River through the day.
KMSP...Another round of light precip as rain/snow should move in
between 11-14Z. Then, scattered showers likely continuing for the
rest of the day. Winds should increase markedly as the precip moves
in late tonight.
/OUTLOOK FOR KMSP/
MON...VFR. Chc MVFR cigs. Wind NW 15-20G30kts.
TUE...VFR. Wind NW 10-15G20kts.
WED...VFR. Wind SW 5-10kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...CTG
AVIATION...Borghoff
Area Forecast Discussion
National Weather Service Pocatello ID
133 PM MDT Sat Apr 29 2023
.SHORT TERM...Tonight through Sunday night. Upper ridge axis
sharpens and shifts overhead during the day Sunday. Southerly flow
develops during the day Sunday and continues into Monday. The GFS
and Hi-Res derivatives show mid level moisture streaming into the
central mountains and potentially the Magic Valley, with the HRRR
also showing a slight hint of convective development. At this
time, believe this is overdone with little support in the NAM and
other high-res model solutions and thus also the HREF, though
wouldn`t be surprised to see a sprinkle or two and locally gusty
winds. Temperatures and subsequent ongoing snow melt remain the
main concerns, with temperatures surging into the 70s and 80s
across many lower elevation areas and temperatures remaining above
freezing overnight especially in lower elevations. DMH
.LONG TERM...Monday through Saturday. Omega block in place for first
half of the week. Our weather will be mainly dominated by a ridge
which will produce temperatures roughly 15 degrees above normal.
This will likely accelerate snowmelt with worsening flooding
conditions likely. A low pressure area stationed near the central
California coast will push enough moisture into central and east
Idaho to fuel isolated showers and thunderstorms. This will remain
the case until late week when the ridge weakens and the low is able
to move further inland. Nearly all model solutions show this
occurring but differ significantly in how this will occur. So
confidence in cooler (closer to normal) temperatures with widespread
precipitation late week is high. However, confidence with regard to
timing, precipitation amounts and how that will factor into the
flooding situation is low.
13
&&
.AVIATION...VFR conditions likely today with mainly upslope/upvalley
winds today becoming downslope/downvalley tonight. A few models are
indicating an isolated dry shower or thunderstorm near KSUN this
afternoon. Will continue to monitor to see if this develops, but at
this point confidence is not strong enough to mention in TAF.
13
&&
.HYDROLOGY...Strong warming trend continues into next week.
Overnight lows will remain above freezing for most lower
elevations, even up to some mid slope areas, and daytime highs
will remain very warm. Runoff is expected to increase into creeks
and streams, and flooding of low-lying fields and flood-prone
areas is likely. Snowmelt forecasts from NOHRSC indicate around or
over an inch of snow-water melt through tonight, then another inch
on Sunday. Temperatures jump significantly Monday, and the
forecasted snow-water melt from NOHRSC jumps to 2" in some areas.
River forecasts continue to show a strong response. The Big Wood
at Hailey remains within or very near action stage and could reach
flood stage as early as Monday night. The Little Wood above High 5
Creek continues to flirt with flood stage every night with minor
flooding upstream, and is trending upwards. The Portneuf River
remains a significant concern, already into minor flood with a
very high probability of reaching moderate flood Sunday evening.
Latest projections give the Portneuf at Pocatello a roughly 60%
chance of exceeding MAJOR flood Stage. Additional concerns are
starting to reach the Portneuf further upstream at Topaz, which
may necessitate stretching the Flood Warning further upstream from
the current polygons. The Bear River at Border currently looks to
reach flood stage Monday. Existing FLOOD ADVISORY and FLOOD
WARNING products will remain in place currently, with potential
for further upgrades and additions depending on how the rivers
react overnight to today`s temperatures. Otherwise, the AREAL
FLOOD WATCH remains in place with one addition. Have added the
Stanley area to the FLOOD WATCH in anticipation of potential
concerns along Valley Creek and further upstream into the Stanley
Basin. If temperatures rise warmer than anticipated, flooding risk
may continue to escalate area-wide. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday afternoon for IDZ056>059-061>068-072-075.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
918 PM EDT Sat Apr 29 2023
.SYNOPSIS...
Low pressure over the lower Mississippi Valley region will track NE
across NC Sunday morning. The associated cold front will track east
across NC Sunday afternoon and evening, then offshore Sunday night.
High pressure will bring drier and much cooler conditions early to
mid week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 918 PM Saturday...
The latest data analysis indicated an arc of showers (thunderstorms
mostly offshore of the SC coast) associated with the old
MCV/convective complex to our south. The showers extended from Atlanta to
Charleston moving north-northeast. In addition, the cold front and
surface low pressure were located over the lower MS valley extending
into AL. Although the dew points have been coming up and the
boundary layer moisture increasing, central NC remained stable this
evening with a thickening of high cloudiness. It appears the HRRR is
doing a better job with the arc of showers to our south that is
expected to push northward across our region later tonight. The
stronger convection is expected to remain along the coast or in the
Gulf Stream just offshore. Low pressure is expected to translate to
central or SE GA late tonight, then track NE across SC/NC Sunday
morning into the early afternoon. It appears that HRRR and
operational models are honing in on a warm front to push into the
Coastal Plain later tonight and early Sunday as the first band of
showers moves north and brings a lull in activity here. Additional
convection is expected to form near and along the low pressure track
Sunday morning. Bottom line, this first band of showers/iso thunder
is not expected to have severe weather associated with it. We will
have to wait until the next round arrives mid to late morning for
the severe potential to increase. The warm frontal position will be
critical to the placement of severe storms Sunday. The Coastal Plain
and Coast appear to be most at risk, with the Piedmont possibly too
stable. We will simply bring the chance of showers in a bit quicker
with this update tonight. Otherwise, the forecast rational has not
changed. Lows in the upper 50s to mid 60s.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 250 PM Saturday...
...There is a Slight Risk for severe weather on Sunday across
eastern NC...
On the larger scale, a compact shortwave rounding the base of the
upper low over MN/WI, and its associated surface low will lift north
across the central NC on Sunday. Multiple rounds of storms are
possible late tonight through Sunday afternoon. The first will be
associated with a convective impulse lifting out of the Gulf Coast
states today, followed closely by the northward/inland push of the
warm front associated with the aforementioned surface low and then
then upper shortwave and trailing cold/effective front. With strong
deep layer shear and forcing for ascent, the limiting factor will be
destablization during the day on Sunday.
First, it appears the MCV will race north across the area tonight
and exit to he northeast well before 12z. It is possible that the
subsidence in the wake of the MCV and any associated convection
could help to initially limit storms in the 12-15Z time frame when
the warm front and more theta-e rich are poised to surge into the
coastal plain, and hodographs are most strongly curved. Given this,
confidence in the early morning severe threat is low, but this is
likely when any low-end tornado threat would be greatest.
Additional destablization from daytime heating is also questionable
through Sunday afternoon given widespread early cloud cover, only
minimal intrusion of dry air ahead of the shortwave, and muted
dewpoints in the upper 50s to lower 60s...except for areas east of I-
95 where dewpoints are progged to reach the upper 60s. Models
generally suggest 1000-1500 MLCAPE near and east of US 1. That
said, the surface low is forecast to strengthen to near 990mb over
central NC as the shortwave becomes negatively tilted. The most
vigorous pressure falls are forecast as the low lifts toward the
northern coastal plain, so if there is an area where elongating
hodographs and gradual destablization overlap with the best deep
layer lift, it may be northeast of the Triangle after 15Z. The
primary threat during the day will be damaging straight line winds
and large hail.
Convection should be departing the northeast CWA by 21Z, with the
trailing cold front forecast to swing through the area between 00Z
and 06Z Monday (Sunday evening). Cannot rule out some isolated
showers with the front, but deep layer lift won`t be as strong and
moisture will have moved off to the northeast as well. Modest
pressure rises in the wake of the departing low should maintain some
decent wind gusts of 20-25kt well on into the late evening and early
overnight period before finally dying off Monday morning. Lows in
the upper 40s and lower 50s.
Regarding flooding potential...a couple rounds of showers and storms
in the east, with another batch of precip in the western Piedmont
likely during the day as the upper wave crosses the area should
produce another 0.5" to 1.5" of rainfall, with some likely higher
amounts. The western Piedmont received over an inch of rain early
Friday, so those areas are a bit primed, but any risk of flooding
should be tied to multiple rounds over one location or training of
storms, so the flood threat is generally low.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 300 PM Saturday...
...Cool and Windy for the First Half of the Work Week...
Omega block over the CONUS will maintain an amplified upper low over
the Great lakes through mid-to-late week, resulting in below normal
temperatures and generally dry conditions under westerly flow. It`s
possible that a rippler or two rounding the base of the upper trough
could bring some periods of cloudiness and light showers or
sprinkles, especially around midweek as a reinforcing cold front is
forecast to push into the area, but areas east of the Appalachians
are forecast to remain mostly dry in the absence of better deep
moisture. The upper jet will be positioned overhead during this
period and should translate to gusty winds east day and perhaps some
fire weather concerns by Wed after a couple days of drying out.
Highs will be in the mid 60s to lower 70s Mon-Wed, warming Thu/Fri
with the a lot of uncertainty as to whether another system with
precip will reach the area Fri/Sat or not.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 704 PM Saturday...
VFR CIGS will lower as showers move into the southern part of NC
late this evening and through the region overnight. Expect IFR to
LIFR conditions later tonight through mid-morning Sunday with
showers/fog. Another round of showers and isolated thunderstorms is
expected Sunday morning through the early afternoon, then scattered
thunderstorms ahead of the cold front Sunday afternoon and early
evening.
Beyond 00Z Monday: A return to VFR conditions are expected Sunday
night. These conditions should late though much of the upcoming
work week.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett
NEAR TERM...Badgett
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...Badgett
Area Forecast Discussion
National Weather Service Salt Lake City UT
347 PM MDT Sat Apr 29 2023
.SYNOPSIS...High pressure will bring warming temperatures more
reminiscent of early summer through early next week. A cooler,
unsettled pattern is expected to develop Thursday, and continue
into next weekend.
&&
.DISCUSSION...An expansive mid level ridge encompasses much of the
western CONUS this afternoon, which is allowing for sunny skies
and a considerable warming trend. RAP 700mb analysis shows
temperature ranging from 6C across northern and eastern UT, to 8C
across the southwest. Mixing this warmer air mass to the surface
has allowed temps to reach the mid to upper 70s along the Wasatch
Front this afternoon, and around 90 in the St George area. This
ridge will shift east slightly on Sunday, allowing 700mb temps to
approach 10C across northern UT, and 11C across the south. This
will push max temps in to the low to mid 80s along the Wasatch
Front, while a more muted warming trend across southern UT pushes
max temps 2-4 degrees warmer. This warming will continue to fuel
snowmelt across the area, allowing rivers, creeks and streams to
continue running cold and swift. Flood watches remain in effect
for mainstem rivers forecast to approach or exceed flood stage
heading into early next week.
The mid level ridge axis will shift east of the forecast area
early next week, as an upper low currently spinning off the
Pacific coast begins to spread inland. Increasing southerly flow
ahead of this low will result in windy conditions Monday afternoon
across western UT, and mid level moisture coupled with weak large
scale lift will bring a small threat for high based convection
across northern UT Monday afternoon and evening. Otherwise the air
mass across the forecast area will remain very warm, with 10C
700mb temps maintaining 80 degree temps across the Wasatch Front,
and near 90 around the St George area.
The upstream upper low is forecast to slowly spread inland during
the latter half of the upcoming week, allowing a couple of
shortwaves to lift across the forecast area. The initial wave
ejects across the eastern Great Basin Thursday bringing cooler
temperatures and a band of precipitation along the associated
baroclinic zone. A second wave follows late Friday through
Saturday bringing a re-enforcing shot of cooler air along with
another chance of precipitation area-wide.
&&
.AVIATION...KSLC...Mostly clear conditions will last through much of
the evening with scattered high clouds overnight. Northwest winds
will transition to southeast around 03Z.
.REST OF UTAH AND SOUTHWEST WYOMING...Mostly clear conditions will
transition to scattered high cloud cover with light winds through
the overnight. Southwest winds gusting around 25 knots are likely
throughout southern Utah by around 18Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch through Friday morning for UTZ107.
WY...None.
&&
$$
Seaman/Wilson
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity