Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/01/25
Area Forecast Discussion
National Weather Service Bismarck ND
946 PM CDT Wed Apr 30 2025
.KEY MESSAGES...
- On Thursday, there is a 40 to 80 percent chance of showers
across the state with the best chances over the central. A few
thunderstorms are also possible.
- Above-normal temperatures and dry conditions are forecast to
return this weekend. Widespread highs in the 80s are possible
on Sunday, along with some breezy conditions.
- Low to medium precipitation chances return late Sunday night
through Tuesday. A few thunderstorms are possible on Monday.
&&
.UPDATE...
Issued at 944 PM CDT Wed Apr 30 2025
Rain has just about exited the area tonight. Some little pop-up
showers developed over Dickey County, with a few flashes of
lightning, though they fell apart pretty quickly. No changes
were needed with this update.
UPDATE
Issued at 631 PM CDT Wed Apr 30 2025
Light precipitation continues to move across the southeast,
waning off towards sunset. Not much in terms of total
precipitation is falling out of this anymore. Otherwise, apart
from overcast skies, some fair weather cumulus has formed across
the northwest. Cloud cover should dissipate briefly overnight,
before the next wave approaches early tomorrow morning. No major
changes were needed for this forecast update.
&&
.DISCUSSION...
Issued at 131 PM CDT Wed Apr 30 2025
Western and central North Dakota is currently under the
influence of low amplitude southwest flow aloft as a shortwave
trough continues to propagate through the region. Plenty of
cloud cover continues to stream across western and central North
Dakota as the wave moves through and a band of light rain also
continues to slowly move across the state from west to east
behind a cold front. We should start to see a little bit of
clearing from west to east later this afternoon and into the
evening, but the main core of the trough will approach
overnight, increasing cloud cover once again. Overnight lows
will range from the upper 30s to the mid 40s.
The trough axis moves through Thursday morning, leaving western
and central North Dakota under cyclonic flow aloft through the
rest of the day. This pattern will lead to widely
scattered/numerous showers (40 to 80 percent chance) and a few
hit or miss thunderstorms with the best chances over the
central. Instability and shear should be fairly weak with RAP
soundings suggesting up to around 500 j/kg of MUCAPE and deep
layer shear only maxing out in the 20 to 30 knot range. Thus, a
report or two of small hail is not out of the question, but the
strong to severe threat appears low. Precipitation amounts this
afternoon through Thursday should generally be light. NBM
probabilities for amounts greater than or equal to a tenth of an
inch range from around 40 to 80 percent across the southern
half of the state (and up into portions of the Devils Lake
Basin). But increasing that threshold to a quarter inch or
greater and the probabilities only max out around 20 percent.
The one exception could be the far southern James River Valley
where some modestly higher totals are possible, or under any
heavier showers/storms that develop on Thursday. Highs may be
just a bit cooler than today on Thursday, ranging from the mid
50s to the mid 60s.
An expansive west coast ridge will start to nudge closer on
Friday as we transition back into highly amplified northwest
flow aloft. This ridge will slowly move across the northern
Plains through the weekend, promoting dry conditions and warming
temperatures. Highs on Friday will range from the lower 60s
(maybe some upper 50s) southeast, to the upper 60s northwest.
Highs will mainly be in the 70s on Saturday with an outside shot
at a few lower 80s across the far west and then Sunday should
see widespread highs in the upper 70s to the mid 80s as the
ridge axis moves across the region.
After the ridge axis passes through, we transition back into
southwest flow aloft later in the day on Sunday and into the
nighttime hours as a split flow regime develops. While most of
the forcing will either stay north of the International border
or south of the South Dakota border, we should still see low to
medium precipitation chances return late Sunday night through
Tuesday with the best chances along and behind a cold front that
will move through on Monday. Monday will also see the return of
thunderstorm chances as GFS soundings suggest MUCAPE up to
around 500 J/kg and deep layer shear up to around 40 knots.
Thus, a stronger storm or two may not be out of the question
depending on how the forecast evolves. CSU Machine Learning
guidance is also suggesting a low chance for severe
thunderstorms on Monday so it will be a period to monitor
closely. As of now, precipitation amounts appear to be on the
lighter side next week with NBM probabilities of a tenth of an
inch or more maxing out in the 30 to 50 percent range.
Increasing the threshold to a half inch and the probabilities
only max out at 20 percent. Highs will be cooler west on Monday
behind the cold front, ranging from the mid to upper 60s
northwest, to the upper 70s southeast. Highs on Tuesday will
then range from the mid 60s to lower 70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 631 PM CDT Wed Apr 30 2025
VFR conditions are present across the area, with a thick layer
of high clouds covering much of the state. Some scattered mid-
level cumulus have also formed across the northwest. Generally
light north-northwesterlies, with some slightly breezier winds
in the northwest, will decrease to light and variable overnight,
becoming 15 to 20 mph out of the northwest towards the end of
the TAF period. Clouds will dissipate overnight, before more
overcast conditions return towards the end of the TAF period,
along with chances for rain showers and possibly some
thunderstorms. Conditions should remain VFR at this time.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Besson
DISCUSSION...ZH
AVIATION...Besson
Area Forecast Discussion
National Weather Service Fort Worth TX
711 PM CDT Wed Apr 30 2025
...New Short Term, Aviation...
.KEY MESSAGES...
- Strong to severe thunderstorms are ongoing across Central Texas
with damaging winds, large hail, flash flooding, and a few
tornadoes all likely hazards through tonight.
- There is low potential for storms in western Central Texas
Thursday afternoon and evening, some of which could become
strong to severe.
- An additional flooding and severe threat will arrive Thursday
night into Friday with another complex of thunderstorms.
- Nice weather arrives in time for the weekend, followed by more
storm chances early to mid next week.
&&
.SHORT TERM... /NEW/
/This Evening Through Thursday Night/
Our clusters of thunderstorms will continue to develop and move
south/southeast tonight along and ahead of a slow-moving surface
boundary. With said boundary being through a majority of the
region, our western counties will remain quite tranquil through
the tonight. Latest RAP analysis shows up to 2000 J/kg of MLCAPE
ahead of the boundary, which coupled with 7 degC/km lapse rates
and ~50 KT of deep layer shear (per SPC mesoanalysis), will
promote a continued severe threat confined to areas in Central
Texas that are south of I-20 and east of I-35 the rest of this
evening. Large hail and damaging winds will remain the main
threats. A couple tornadoes remain in the realm of possibility as
efficient ingestion of 0-1km streamwise vorticity will remain
present along and south of the boundary. This tornado threat will
be enhanced with any more discrete cell that forms, so remaining
weather aware tonight will need to be a priority. Periods of heavy
rain will also persist, which will continue the flood threat
through the evening hours. Most, if not all, activity will come to
an end around 1 AM as the upper level shortwave trough moves E-NE
across the Panhandles through Oklahoma overnight. A surge in low-
level stratus will move across portions of the region overnight
into Thursday morning, with some light mist/patchy fog possible
near daybreak. Lowered visibilities may impact the morning
commute, so make sure to drive carefully tomorrow morning!
Thursday will be a much quieter day compared to today, with skies
scattering out and afternoon highs peaking mainly in the 80s. CAM
guidance continues to highlight western Central Texas as an area
of diurnal storm development over the afternoon hours near where
the dryline bulges a bit further east into the Big Country, with
forecast soundings showing around 4000-5000 J/kg of mixed layer
instability in this area. Storm mode would promote more discrete
cells as the 0-6 km shear vector is orthogonal with the dryline.
With that amount of instability, deep layer shear ~35-40 KT, and
lapse rates ~7 degC/km, any storm that is able to develop and
grow could easily become severe with large hail and damaging winds
the main threats. The tornado threat would be low as low-level
shear and SRH are rather lackluster, however it will remain non-
zero as analogs do list tornadoes that have previously occurred
with similar forecast soundings. The caveat to this scenario is
the lack of a more focused source of ascent which may inhibit
coverage and development.
The better opportunity for showers and storms will be late
Thursday night into Friday morning as a cold front advances south
into North Texas. By the time the front sags across the Red River,
storms that have already developed along the front will grow
upscale into more of a linear storm mode as the 0-6 km shear
vector becomes more parallel to the boundary. Strong to severe
storms will be possible with this activity across portions of
North Texas, with the main threat damaging winds accompanied by
more isolated large hail. This activity is talked about in more
detail in the long term discussion below.
Prater
&&
.LONG TERM... /Issued 143 PM CDT Wed Apr 30 2025/
Update:
No major changes have been made to the long term forecast. Another
complex of storms is increasingly likely Thursday night into
Friday that will shift southward from North Texas into Central
Texas. There would be a threat for large hail with this activity
as well as a potential for damaging winds if the complex can
become well organized. Due to the flooding from today and a small
break in between activity, a flood threat will exist with these
storms as well but exact locations where this threat will
materialize more is still uncertain.
Gordon
Previous Discussion:
/Thursday Night Onward/
As the midweek shortwave exits to the Ohio Valley, another
shortwave will dive southeast through the Plains at the start of
the period. Thunderstorms are expected to develop across the
Central and Southern Plains, bringing another round of convection
to North Texas Thursday night into Friday. Convection will be
focused along a stronger cold front, which will be driven
completely through the CWA Friday evening. A damaging wind threat
will likely accompany these storms as they push south through the
region. The passage of the front and development of a ridge aloft
will then provide a couple of nice weather days this weekend.
Saturday through Monday will feature mostly sunny days and clear
cool nights with lows in the 50s and 60s, and highs mainly in the
70s. A slow-moving upper low will then bring more storm chances as
it emerges from the Rockies into the Plains during the early to
middle part of next week.
30
&&
.AVIATION... /NEW/
/00Z TAFs/
Storms are only impacting ACT at this time, and will continue to
do so through ~01Z before finally moving east. IFR-MVFR cigs
across D10 will gradually lift over the next couple of hours back
to VFR. This improvement will only be temporary as another deck of
MVFR-IFR stratus will overspread D10 after midnight, accompanied
by light and variable winds. Prevailing IFR cigs remains a bit
more uncertain at this time, and have included them in a TEMPO
with lowered visibilities and patchy BR between 11-15Z,
potentially impacting the morning push. MOS guidance has begun to
highlight potential LIFR cigs and vis in D10 between 09-15Z, but
these probabilities are low enough (but slightly increasing with
each iteration of guidance) to keep out of the TAF. We will watch
overnight to see if flight categories need to be lowered further.
Winds will settle out of the south overnight, and will remain in
south flow through the rest of the period.
Prater
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation may be requested across parts of Central Texas
through this evening. Even if activation is not locally
requested, any reports of hazardous weather to the National
Weather Service are appreciated.
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 61 86 64 78 59 / 40 5 20 70 60
Waco 64 87 66 80 61 / 70 20 20 80 70
Paris 62 82 62 74 56 / 60 5 20 70 50
Denton 56 84 60 76 53 / 20 0 30 80 50
McKinney 60 83 62 76 56 / 50 5 30 80 50
Dallas 63 86 65 78 60 / 50 5 20 70 60
Terrell 63 83 64 78 58 / 80 5 20 70 60
Corsicana 65 86 67 81 61 / 90 5 10 80 70
Temple 66 90 66 83 61 / 70 20 20 80 70
Mineral Wells 55 88 61 77 55 / 5 0 20 70 50
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday morning for TXZ095-106-107-121>123-
135-146.
Tornado Watch until 8 PM CDT this evening for TXZ135-146>148-
158>162-174-175.
&&
$$
Area Forecast Discussion
National Weather Service Grand Rapids MI
736 PM EDT Wed Apr 30 2025
.KEY MESSAGES...
- Showers and Chance of Storms Tonight into Friday
- A Little Cooler This Weekend, A Little Warmer Again Next Week,
Some Chances for Showers
&&
.DISCUSSION...
Issued at 342 PM EDT Wed Apr 30 2025
- Showers and Chance of Storms Tonight into Friday
Potential impactful weather Thursday includes a slight chance of
lightning strikes within both a batch of rain that will move through
during the morning, and scattered showers developing in the
afternoon. There is also a chance of southwest winds gusting to 40
mph during the afternoon.
A low pressure system will track through Lower Michigan on Thursday.
Ahead of the surge of warm air into southern Michigan Thursday
morning, a period of moderate to heavy rain is highly likely in
western and central Michigan, especially near and north of Holland,
Grand Rapids, and Alma. This is where rain totals greater than 0.50
inch are most favored, and over 1 inch is possible the closer to get
to Ludington per the HREF mean. To the southeast, morning rain could
be more intermittent, but also showers will redevelop later in the
afternoon, providing more hit-or-miss higher totals but generally
0.25 to 0.50 inch is favored.
The thunderstorm threat is marginal, first with elevated instability
within the morning batch of rain, then with afternoon surface-based
instability within the warm sector to the south and east of Grand
Rapids. CAPE values among various short-term models are rather
meager, and instability is focused the lower troposphere which
wouldn`t favor robust updrafts extending to layers colder than -10
Celsius. This will keep the lightning and hail threat subdued. Wind
fields in the warm sector in southern Michigan Thursday afternoon
will be increasing and low-level mixing should make things breezy
even without any help from showers/storm cells. The exact strength
of winds will depend on how much the low deepens is it tracks
through (the 12Z HRRR being in outlier in how intense the low is).
Maintained a chance of showers through Friday as additional
shortwave troughs within the larger-scale trough that`s digging into
the Midwest may touch something off, though models differ quite a
bit.
- A Little Cooler This Weekend, A Little Warmer Again Next Week,
Some Chances for Showers
Large-scale upper-level troughing over the region will keep high
temperatures in the 50s and 60s during the weekend. Some frost or
near-freezing temperatures could occur in Central Michigan Saturday
morning and Sunday morning. Global models have been pointing toward
a pair of upper-level lows over the CONUS becoming cut off from the
northern stream early next week. The eastern cutoff low should be
just south or southeast of Michigan, but in close enough vicinity
that it could touch off occasional showers between Sunday and
Tuesday per the ENS and CMC. The GEFS is drier with the low farther
southeast.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 736 PM EDT Wed Apr 30 2025
VFR conditions are expected for the next few hours with light east
to southeast winds. Conditions deteriorate to MVFR late Wednesday
night, with a decent chance for IFR by Thursday morning. Showers
will be light initially, with increasing coverage and intensity
after 10z. After 10z, visbys under 3SM are possible (3-5SM or
lower likely) for GRR and MKG with the other terminals favored to
drop into the 3-5SM range. Cannot rule out an isolated
thunderstorm Thursday morning but confidence in where and when is
too low for PROB30s. Showers become more scattered into the
afternoon, where instability once again makes isolated
thunderstorms possible. Closer to the surface low track,
conditions should remain IFR at MKG and GRR through the end of the
TAF period. For all other terminals a period of improvement to
MVFR is expected. Winds also increase south and east of GRR
Thursday afternoon with gusts to 25 knots, locally higher possible in
an afternoon shower/storm.
&&
.MARINE...
Issued at 342 PM EDT Wed Apr 30 2025
There is potential that a Small Craft Advisory will be needed during
the day Thursday. The hazard would be winds occasionally gusting
over 22 knots, and a small but not zero chance of winds temporarily
gusting over 30 knots. A low pressure system is expected to track
over Lake Michigan Thursday morning into early afternoon. Models
differ slightly in the exact track and the intensity of the low,
which has repercussions on the wind forecast. Generally, winds early
Thursday morning will be from the east and may have some gusts
around 20 knots. Later in the morning to early afternoon, winds may
shift southwest, most likely in areas south of Muskegon. If the low
is fairly strong, there could be a period of hazardous wind gusts
during these southwest winds. Winds will then shift west-northwest
later in the afternoon.
Additionally, a few lightning strikes are possible within a batch of
rain that will move through Thursday morning.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...CAS
AVIATION...Thomas
MARINE...CAS
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
720 PM CDT Wed Apr 30 2025
.KEY MESSAGES...
- There is a level 2 of 5 (slight risk) late this afternoon and
this evening covering mainly southeast Illinois. Large hail,
damaging winds, and a tornado or two are possible.
- Showers and storms through tonight may generate heavy rain,
leading to localized ponding of water in typical flood prone
areas. There is a level 1 of 4 (marginal) risk for excessive
rainfall.
- Tomorrow, there is a level 1 of 5 (marginal) risk for severe
weather southeast of a Springfield to Bloomington line. Wind
and hail are the main risks.
&&
.UPDATE...
Issued at 720 PM CDT Wed Apr 30 2025
Forecast concern over the next couple hours is isolated supercells
near the I-70 corridor, where a Tornado Watch is in effect until
10 PM. Forcing is on the weak side, resulting in sparse coverage,
however the thermodynamic environment shows around 50 kt
effective deep layer shear on the northern edge of a 1000 J/kg
MLCAPE gradient. The storms we are watching are north of the warm
front, which was analyzed near I-64, and with favorably backed
winds, simulated hodographs over SE IL show good curvature in the
low levels. Thus tornadoes and hail will be a concern with the
strongest cells until instability diminishes later this evening.
Aside from the severe risk, a general uptick in coverage of
showers/storms is expected this evening and overnight over much of
the CWA ahead of a weak wave of low pressure. Locally heavy rain
will be the main feature of these storms, with latest CAMs showing
pockets of 1-2"+ rainfall overnight.
25
&&
.DISCUSSION...
Main concern in the near term will be the potential for a few
severe thunderstorms with the main concern southeast of a
Taylorville to Paris line tonight. Latest satellite imagery is
showing significant clearing in the wake of this morning`s MCS
with stable wave clouds along the warm front and cloud streets
to the south. The RAP is showing this warm front moving north
into the southeast Illinois counties with MLCAPES increasing
into the 1000-2000 J/kg range with deep layer shear of 40-50
knots supporting a few organized multicells and supercells late
this afternoon into this evening. Large hail, damaging winds,
and a tornado or two will be possible with the strongest storms,
particularly along the warm front where there will be the best
low level curvature. Locally heavy rainfall is also possible
given PWATS near 1.75" and the potential for training.
The showers and thunderstorms will then lift north overnight
with the warm front before a upper trough will move across the
area along with an attendant cold on Friday. Have gone with
likely/ categorical PoPs along the front. There remains some
potential for a few severe thunderstorms over the eastern half
of the CWA on Thursday afternoon into early evening, with large
hail and damaging winds being the main threat. The chance for
showers and thunderstorms will diminish overnight on Thursday
night as this first trough moves off to the east.
There will be additional chances for showers Friday through
Sunday as the LREF is showing a trough moving across the area
into Sunday with 20 to 40% of the ensemble members producing
rain during this period. After a brief cool down over the
weekend, the NBM is showing temperatures warming back up
next week.
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 602 PM CDT Wed Apr 30 2025
MVFR ceilings, with patches of VFR were common across central IL
early this evening. This will continue for the next several hours,
while scattered showers and a few storms increase from the south,
associated with an approaching warm front. IFR ceilings are
forecast to slowly spread west to east across central IL
overnight, persisting into late morning then lifting and
scattering out during the afternoon. Scattered showers and a few
storms are possible on Thursday but expected coverage is too low
to include at this range. East winds tonight will veer south with
the warm frontal passage late, then continue to veer west by Thu
afternoon. 20-25 kt gusts will be common for much of the daylight
hours, particularly near/east of I-55.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
912 PM EDT Wed Apr 30 2025
.KEY MESSAGES...
- Scattered strong to severe storms in SW and South Central
Indiana til 11pm
- Primary threats this evening include damaging winds, hail, and
isolated tornadoes
- Additional showers and storms late tonight into tomorrow
afternoon, a few of which could be strong
&&
.FORECAST UPDATE...
Issued at 910 PM EDT Wed Apr 30 2025
Surface analysis this evening shows a warm front over far southern
Central Indiana, slowly pushing north. The ongoing convection was
found along and near this boundary. Easterly surface flow was found
to the north, across the majority of Central Indiana. Conditions
will remain favorable for isolated severe thunderstorms with hail
and isolated tornadoes remaining possible through the end of the
tornado watch. A second area of convection was found approaching
the mid-Mississippi valley and southeast MO.
HRRR suggests then warm front will continue to surge northward
overnight, pushing the isolated convection along with it. As we lose
heating and instability, severe threat across Indiana should
diminish, but isolated non-severe thunderstorms will still remain
possible. Given the limited coverage, more locations will not see
precipitation than locations that will. Thus will lower pops as
confidence for high likely or categorical pops appears too high.
Late overnight, towards daybreak, the leftover precipitation from
the Mississippi convection should arrive in central Indiana. Thus
after a few dry hours overnight, pops will need to return for the
morning rush hours.
Given our southerly flow and cloud cover overnight, temperatures
should not fall too much and lows mainly in the low to mid 60s will
be expected.
&&
.MESOSCALE UPDATE...
Issued at 650 PM EDT Wed Apr 30 2025
SEVERE CONVECTION ALONG SLOWLY NORTHWARD RETREATING WARM FRONT WILL
CONTINUE TO ENCOUNTER A REGION OF MODERATE LOW LEVEL SHEAR (0-1 KM
SRH 100-150 M2/S2) WITH MODERATE INSTABILITY (CAPE 1500-2000 J/KG)
ADDITIONAL CONVECTION ROOTED IN HCR LINES ON SATELLITE OVER FAR SW
INDIANA WILL INCREASE IN INTENSITY ENCOUNTERING THE GREATER LIFT
OVER THE WARM FRONTAL BOUNDARY THROUGH 00Z.
A MODEST INCREASE IN LOW LEVEL FLOW/DEEP MOIST CONVERGENCE INTO THE
EVENING HOURS SHOULD SUPPORT A CONTINUED THREAT FOR SEVERE
CONVECTION THROUGH AT LEAST 02Z WITH Attendant THREAT FOR
ISOLATED TORNADOES WITHIN WW 200. ALTHOUGH CONVECTION WILL LIKELY
PERSIST AFTER 02Z...INCREASING LOW LEVEL CONVECTIVE INHIBITION
WILL AID IN A WEAKENING OF THE TORNADO Threat. HOWEVER AN
ISOLATED SEVERE HAIL/WIND GUST THREAT MAY REACH THE IND METRO AREA
BETWEEN 02-04Z.
&&
.SHORT TERM (This evening through Thursday)...
Issued at 303 PM EDT Wed Apr 30 2025
This evening...
Focus this evening and tonight will be on portions of Southwest
and South Central Indiana as scattered thunderstorms develop
along a warm frontal boundary slowly pushing north through the
state. Hi-res CAMs have been consistent over the past 24 hours in
showing the potential for scattered strong to severe storms in
this region right along the aforementioned boundary. IND ACARs
soundings this afternoon show an environment north of the boundary
characterized by drier and stable low levels, not conducive for
sustained severe weather development. South of the boundary, SDF
ACARs sounding shows a very different airmass characterized by
steeper low level lapse rates, mid to upper 60s dew points,
sufficient CAPE, backed SE low level winds, and sufficient
effective bulk shear and helicity to support discrete supercells
and severe weather. Therefore, main focus area will be along and
south of the warm frontal feature, particularly in Knox, Daviess,
and Martin counties...and to a lesser extent surrounding counties
depending on how far north this boundary moves. Timing looks to be
5pm - 10pm for the best chance for any severe storms, with the
potential for a marginal severe threat to extend up to the I-70
corridor 9pm to 2am as the front moves northward...however
confidence in the extent of the severity northward is lower, but
still high enough threat to mention here and monitor. An
increasing low level jet and warm frontal push could be enough to
allow for severe storms to persist northward, so keeping a close
eye on where the frontal boundary sets up. Storms that outpace the
warm front likely would weaken fast in a more stable environment.
Late tonight into tomorrow...
Toward the latter half of the overnight hours and into the early
morning, short term guidance shows isolated to scattered showers
and storms still around within the broad warm sector ahead of a
cold front to the west. Lower confidence in the coverage of
showers or storms 06z onward into the morning; however an
increasing low level jet, unidirectional SW shear through the
column and a skinny CAPE profile may lead to a heavy rain threat
with convection moving over the same areas. Marginal risk for
severe weather exists during this timeframe; however with waning
instability, thinking the main threat will be heavy rain and
lightning.
The main area of low pressure pushes northeast through Illinois and
Michigan during this time frame and tomorrow with a cold front
hanging back until the evening hours, leaving Indiana within the
broad warm sector nearly all day Thursday. Depending on how
widespread morning convection is and how long it persists, there
could be a secondary round of convection during the mid afternoon
to evening hours tomorrow. If the atmosphere is able to recover,
forecast soundings show an environment conducive for discrete and
multicell storms capable of producing damaging winds and hail
before the cold front pushes through. The coverage and severity of
this round will likely depend on how much recovery takes place
after morning convection; therefore confidence is only marginal at
the moment, but will rise tonight as we see how overnight and
early morning convection evolves.
During this time, expect above average lows with temperatures holding
steady in the 60s to near 70 overnight and then back into the 70s
tomorrow depending on how much sun is realized and how long the
dry break is.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 303 PM EDT Wed Apr 30 2025
Key Messages:
- Showers and thunderstorms possible Friday afternoon and evening
Friday:
The upper wave will finally reach the Ohio Valley by Friday,
along with a trailing pressure trough. This upper wave will be
rather amplified in the upper levels leading to strong upper level
dynamics. However, the low level kinematics will be lacking
without any strong negative height tendency over the region. With
that said, strong cooling aloft should lead to steep lapse rates
over central Indiana Friday afternoon. The resulting environment
should be isolated to scattered showers and thunderstorms. If
these storms are able to reach the strong dynamics aloft, greater
ventilation could lead to clusters and modest organization, with a
non-zero damaging wind and hail threat. Any severe weather that
does occur should be very isolated.
Without strong forcing in the buoyant sector, overall rain amounts
should be spotty, but generally less than a half an inch, with
most locations receiving less than a tenth. Temperatures will be
curbed some in the afternoon with the greatest warm air east of
central Indiana by Friday. The current expectation is for highs in
the low 70s.
Saturday through Monday:
The upper trough is generally expected to depart to the east this
weekend. With that said, there is some uncertainty on how quickly
the vorticity lobe will be able to exit, with the parent jet
stream well north into Canada. There is currently a bimodal
distribution in the evolution of the upper level pattern with half
the LREF showcasing a cut-off upper low remaining over the Ohio
Valley, and the other half pushing the trough into the Mid-
Atlantic and strong upper level ridging in its wake. If the cut-
off low comes to fruition, temperatures will remain mild with
highs in the upper 50s to 60s and scattered light rain chances and
mostly cloudy skies. On the other hand, if upper ridging
develops, resulting subsidence should allow for mostly clear
skies, highs in the mid to upper 70s and an extended dry period.
Next Tuesday Onward:
Regardless of this weekend`s weather, long range trends are pointing
towards warming than normal conditions for a majority of next
week. As the warm dome of air develops, amplifying waves upstream
could develop leading to a potentially active pattern late next
week/weekend. Confidence on conditions beyond next Thursday is low
though, as of this forecast issuance.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 642 PM EDT Wed Apr 30 2025
Impacts:
- Mainly VFR Conditions, however brief MVFR/IFR conditions possible
in TSRA this evening.
Discussion:
A warm front lifting north across Central Indiana will result in ISO-
SCT TSRA this evening across the TAF sites. Easterly winds ahead of
the front at 00Z will shift to southerly in the wake of the front by
the overnight hours. HRRR suggest convective development across
southern Indiana this evening before lifting northward by late this
evening. This will result in TSRA/SHRA passing across the TAF sites
producing brief MVFR conditions with passage. At this time precip
should end by 04Z, leading to a return to VFR at the Taf sites.
Rain chances will persist on Thursday as the TAF sites remain in the
warm sector and upper forcing is expected to continue to pass within
the quick southwest flow aloft.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Puma
MESOSCALE...CROSBIE/PUMA
SHORT TERM...CM
LONG TERM...CM
AVIATION...Puma
Area Forecast Discussion
National Weather Service Lake Charles LA
902 PM CDT Wed Apr 30 2025
...New UPDATE...
.KEY MESSAGES...
- A Marginal to Slight risk of severe weather risk is in place for
tonight and Thursday morning.
- The next chance of showers and thunderstorms expected Thursday
through Saturday as a cool front approaches and moves across
the area.
- Above normal temperatures will continue through Friday,
returning to near normal for the weekend.
&&
.UPDATE...
Issued at 857 PM CDT Wed Apr 30 2025
Question for the tonight period is the MCS over northeast Texas
and how it will affect the forecast area. There is still some
differences as to how the thunderstorm cluster will hold together
and timing of it all. Right there is enough support it seems that
the cluster will reach the forecast area between 1 am and 2 am
then slowly move southward as weakening to the I-10 corridor
before dawn. Some impressive rainfall rates seen with this
feature, so potential for heavy rainfall as it reaches and moves
into the forecast area. Made some minor adjustments to the
forecast pops based on latest radar and short term guidance.
Rua
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 221 PM CDT Wed Apr 30 2025
Weak ridging is located aloft and at the surface, which will keep
our weather calm for the first part of the day. A trough is
located in west Texas that will bring the first round of active
weather. Overnight, severe weather will be possible with a
conditional threat of damaging winds and large hail. CAMs have
started to become more aggressive with this line but still shows
a wide range of solutions for this system. The HRRR remains the
most aggressive showing a bowing QCLS moving across the region
while the NAM/RAP showing weaker scattered convection.
The kinematics of this event show a mixed bag with large CAPE
values of 2000 J/kg along with DCAPE above 600. Shear will be the
lacking ingredient with effective bulk shear only around 10 knots.
With a lack of shear, getting organized convection to form or
stay organized will be difficult for the storms in our area. One
thing to watch for will be the possible development of an MCV as
the low treks north of us. Which would increase the shear values
across central Louisiana.
By Friday, another upper disturbance will move across the
country. This will drive a cold front south to the area. An
increase in lift and the already in place warm and humid
conditions will allow for an increase in convection. A marginal to
slight risk of severe weather is anticipated away from the coast.
There is also a marginal risk of excessive rain Friday. Over the
weekend this front will stall across the coast, keeping us cloudy
and wet until the start of the work week.
During this time, temperatures will be several degrees above
normal with high humidity.
&&
.LONG TERM...
(Saturday through next Tuesday)
Issued at 221 PM CDT Wed Apr 30 2025
A stationary boundary will keep rain chances high on Sunday and
Sunday night. At the start of the work week a weak cold front will
move across the region, kicking out the front and lowering our
rain chances. With the front will come cooler and drier
temperatures. For the rest of next week we can expect typical
conditions with highs in the mid 80s with lows in the mid 60s.
&&
.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Wed Apr 30 2025
The main question in the aviation forecast is the potential for a
thunderstorm cluster to move down from northeast Texas and
northwest Louisiana into the forecast area. Best indication from
guidance is that cluster will hang together enough to affect the
KAEX terminal between 01/06-07z. It is less certain that the other
terminals will be affected between 01/09-13z.
Otherwise, expect MVFR conditions from low clouds with ceilings
between 1500 and 2500 feet by 01/06z through 01/15z.
Rua
&&
.MARINE...
Issued at 221 PM CDT Wed Apr 30 2025
Surface obs and ASCAT analysis shows winds above 20 knots in our
coastal waters and in the lakes and bays. This increase in wind
is due to an approaching low pressure system in Texas.
Waves will be between 2 and 4 feet.
The next chance of showers and thunderstorms expected Friday and
Saturday as a cool front approaches and moves across the coastal
waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 67 85 65 86 / 40 60 10 60
LCH 72 84 70 84 / 30 30 0 30
LFT 72 85 69 86 / 20 40 10 40
BPT 72 86 70 86 / 40 30 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until 1 AM CDT Thursday for GMZ430-432-435-
436-450-452-455-470-472-475.
&&
$$
SHORT TERM...14
LONG TERM....14
AVIATION...07
Area Forecast Discussion
National Weather Service New Orleans LA
932 PM CDT Wed Apr 30 2025
...New UPDATE...
.UPDATE...
Issued at 930 PM CDT Wed Apr 30 2025
The early evening portion of the forecast is going according to
plan, with some remaining uncertainty as to the progression of the
thunderstorms currently over extreme northern Louisiana and east
Texas. The portion over extreme northern Louisiana is tracking
eastward north of Interstate 20 with some apparent weakening. The
storms over east Texas have been slower to progress eastward with
cell movement around 20 mph.
The 00z LIX sounding was rather dry in the layer between 900 mb
and 500 mb (and precipitable water overall at 1.2 inches), with
very limited shear (0-6km of 16 knots). The LCH sounding at the
same time was a little more moist (1.48 inches), more shear (0-6km
of 37 knots), but also had a bit of a cap around 700 mb. Most
Convection Allowing Models (CAMs), but not all, are supportive of
at least scattered storms reaching the northwest corner of the CWA
prior to sunrise, potentially as early as 3 or 4 AM CDT, although
they may be in a weakened state compared to what has occurred to
the west this afternoon.
Will introduce 20-30 percent PoPs for the late night hours across
portions of the area, as well as during the several hours after
sunrise. Will continue to monitor the progression of the storms to
the west and will not rule out an additional update prior to
midnight.
&&
.SHORT TERM...
(This evening through Thursday night)
Issued at 328 PM CDT Wed Apr 30 2025
Upper level analysis shows a shortwave trough moving east through
New Mexico, another one over ID/MT, and ridge axis from the Gulf of
America to the Eastern Seaboard. That ridge, which has kept the
local area POPs limited at temps above normal, is already becoming
suppressed southward as the troughs approach from the NW. That
slight decrease in subsidence in the northwestward side of the ridge
and the CWA explains current isolated showers northwest of Baton
Rouge. Global models continue to show the 2 shortwaves merging into
one broader trough as they push into the Mississippi River Valley
tomorrow. A surface ridge centered east of the local area will keep
elevated southerly flow in place. It`s not a deep source of moisture
but enough to bring PW`s into the 1.2-1.5" range.12z CAMs show a MCS
moving across northern LA towards the CWA Thursday morning. The
consensus is that convection will be in a decaying state but varying
in timing of if that happens before or after it reaches the local
area. Model soundings across SELA and SWMS support weakening with
any decent instability very elevated. So what happens to the
residual MCS boundary in the afternoon? That`ll probably be the
bigger forecast challenge as CAMs are split on aftn convection.
Probably lean towards at least a few thunderstorms developing
with low-end severe hail/winds possible.
&&
.LONG TERM...
(Friday through Tuesday night)
Issued at 328 PM CDT Wed Apr 30 2025
On Friday, a developing frontal boundary associated with the main
trough axis along the MS Valley will be slowly sagging south through
LA and MS. Should see a bump in PWs along and ahead of the front,
which includes the CWA, as southerly flow persists. Models show most
of the higher rain chances and heavier rain to still be over central
LA/MS compared to solutions from 24 hours ago. Now Saturday appears
to be the one with the potential for heavier rainfall as a stalled
or slow moving frontal boundary draped over the area. The main upper
trough then shifts east into the Western Atlantic later in the
weekend and brings back some normal temps to the region.
&&
.AVIATION...
(00Z TAFS)
Issued at 613 PM CDT Wed Apr 30 2025
All forecast terminals VFR at forecast issuance, except KGPT,
which was reporting BKN025. Expect those ceilings to scatter out
over the next few hours.
Aside from the threat of MVFR ceilings later in the overnight
period, there remains a concern for potential TSRA, both during
the late night hours overnight, and during Thursday afternoon.
Current area of storms in the KSHV area back into Texas is
becoming outflow dominant, but there are several convection
allowing mesoscale models (including the recent HRRR runs) indicating
potential for those storms to reach at least our northwest
terminals (KMCB, KBTR, KHDC) prior to sunrise Thursday before
weakening or dissipating. Will use PROB30 for now, but future
amendments or the 06z package may need to either beef up
probabilities or remove them entirely. The eventual resolution to
those storms will determine how much of a threat there is for
convective redevelopment Thursday afternoon. If the cirrus blowoff
is too thick, it may retard heating enough to prevent
redevelopment, or mesoscale processes could provide a focus to
only impact a few terminals. Will also use PROB30 for Thursday
afternoon for now.
&&
.MARINE...
Issued at 328 PM CDT Wed Apr 30 2025
Surface ridge will be centered northeast of the local marine waters
will transition to more due east of here as it gets shoved
southward across the western Atlantic from the next approaching
system. That`ll both keep winds in our marine zones elevated and
onshore. Should see a gradual directional shift from southeast to
due south simply with the position change of the ridge. Recent obs
show speeds right at that Exercise Caution threshold, so will
have the headline out for tonight. Weaker winds appear more likely
over the weekend as approaching cold front fizzles out.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 67 86 66 84 / 30 70 20 60
BTR 70 88 68 87 / 20 50 0 50
ASD 70 86 68 86 / 10 40 20 50
MSY 73 87 72 86 / 0 40 10 50
GPT 72 83 69 83 / 10 50 20 50
PQL 68 84 67 84 / 10 50 30 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...ME
LONG TERM....ME
AVIATION/UPDATE...RW
MARINE...ME
Area Forecast Discussion
National Weather Service Omaha/Valley NE
Issued by National Weather Service Hastings NE
643 PM CDT Wed Apr 30 2025
.KEY MESSAGES...
- There will be additional rounds of mainly light rainfall
moving through the area this evening/tonight. Can not rule out
a few weak embedded thunderstorms, but shouldn`t be anything
severe. Primary focus for precipitation will continue to be the
Lincoln to Omaha corridor, to along the Missouri River and
eventually into western Iowa.
- Rain showers and a few weak thunderstorms could linger along
the eastward progressing trough axis Thursday morning with a
few additional heat of the day/instability
showers/thunderstorms Thursday afternoon, but less widespread
than today.
- Highs mainly in the 60s through Friday and then 70s this
weekend into next week.
- The weekend appears dry. Precipitation chances then return
late Monday through Wednesday with much uncertainty
surrounding how the next significant upper low will track out
of the western U.S.
&&
.DISCUSSION...
Issued at 235 PM CDT Wed Apr 30 2025
This Evening Through Tonight...
As of 3 PM, a second round of light rain showers was tracking
northeast out of northern Kansas and was just getting into the
Lincoln area. Showers and even a few isolated weak thunderstorms
will continue to develop across this same area and gradually
work back into the Omaha metro area as we head through the
evening hours. Most areas will see less than 0.25 inches of
additional rainfall this evening/tonight, but a few of the
higher amounts could be around 0.50 inches of additional
rainfall. That is on top of the rainfall we`ve already seen
through early this afternoon, which ranged from around 0.50 -
1.00 inch southwest of Lincoln. Rainfall amounts in the Omaha
area through 3 PM have generally been much lighter and less
than 0.25 inches.
The main area of rain should shift east with time, closer to the
Missouri River by late evening and as we close in on midnight,
with most of the rain over western Iowa during the late night
hours. Not everyone will get wet, our northwestern zones may see
very little if any rainfall through tonight. Thunderstorms
currently developing over Cherry County Nebraska at 3 PM will
track east, but should weaken and generally fall apart as they
approach our forecast area late this evening. Severe weather is
not anticipated across any of our area through tonight.
Fog...
Can not rule out some patchy fog late tonight and through
a few hours after sunrise as the surface winds go light within
the trough axis or during lulls in the rainfall just ahead of
the trough axis. The SREF and different HRRR runs indicate at
least a slight signal for fog.
Thursday and Friday (Continued Rain Chances)...
We may continue to see some lingering showers/weak thunderstorms
Thursday morning until the trough passes through the area.
Favored areas Thursday morning will be eastern zones (western
Iowa). Also watch out for patchy morning fog as was mentioned
earlier. There is then a slight chance that with some afternoon
diurnal heating we could see a few convective showers or weak
thunderstorms from late Thursday afternoon through early
evening. This possible scenario is well visualized by the 18Z
HRRR. This would likely be rather isolated, but NBM POPs are not
well reflecting this and are too low. We may need to increase
POPs further.
The next upper level wave will push through Thursday night into
Friday, especially Friday morning bringing additional scattered
showers. Our NBM POPs (30%) may again be too low on this and we
may possibly need to increase these rain chances. Temperatures
will remain cool Thursday and Friday with the scattered clouds
and rain chances keeping highs generally in the 60s.
Saturday and Sunday (Dry and Warmer)...
We will have one upper trough tracking from the Mississippi
River to the Ohio Valley, with another significant trough
digging into the western U.S. this weekend. Right between these
two system you have our forecast area that will be under a big
upper level ridge bringing dry weather with warmer highs back
into the 70s.
Monday - Wednesday...
The western trough will become a big cut off upper level low
over the 4 Corners region of the desert southwest. Forecast
models and ensembles vary on how exactly this system will
actually eject out into the plains regarding both timing and
strength. Monday will likely still be dry, but then Tuesday and
Wednesday are more uncertain. This appears to be a great high
plains rain maker, but then the upper low will likely weaken
some as it finally makes it east towards our area with rain
chances across the eastern half of Nebraska into western Iowa
much more uncertain. This will be a system to keep an eye on as
we get closer. There is also more spread in the model
temperatures during this time, warmer 70s if the clouds and the
rain hold off, cooler 60s if the clouds and rain can eventually
push east into our area.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 640 PM CDT Wed Apr 30 2025
Off/on rain showers remain in the OMA/LNK areas through this
evening and tonight. This activity will initially remain
southeast of OFK, but the line of showers/storms over north-
central Nebraska will eventually reach the OFK area (weakening
as it arrives).
Ceilings are somewhat uncertain. VFR to MVFR ceilings currently
are expected to fall (possibly to IFR) overnight before
improving after a cold front moves through Thursday morning.
Spotty fog is also possible Thursday morning, but confidence in
coverage/location was too low to include in this TAF issuance.
Northwest winds pick up on Thursday in the post-frontal airmass.
Gusts up to 25kts are likely, especially at OFK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Wesely
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Norman OK
710 PM CDT Wed Apr 30 2025
...New UPDATE...
.KEY MESSAGES...
Issued at 710 PM CDT Wed Apr 30 2025
-Scattered storms tonight. Flood watch continues for portions of
southwestern Oklahoma and western north Texas where even a little
additional rainfall over saturated grounds could cause flooding
issues.
-More widespread thunderstorms expected late Thursday night and
Friday morning with locally heavy rainfall. Additional
significant flash flooding possible. Severe thunderstorms will
also be possible.
&&
.UPDATE...
Issued at 710 PM CDT Wed Apr 30 2025
Made some significant adjustments to the POP forecast for this
evening based on current convective trends. Highest POPs will be
in the southwest with the current storms moving in from west
Texas. The expected trend is for these storms to diminish this
evening, but will watch trends and make adjustments if necessary.
&&
.NEAR TERM...
(Rest of today and tonight)
Issued at 249 PM CDT Wed Apr 30 2025
The ongoing severe and flooding risks will persist through tonight
with highest risk across parts of southwest Oklahoma and western
north Texas. HRRR runs consistent with the current storm activity
across our southeast CWA continuing to slowly exit eastward out of
our area along with the surface boundary/cold front as the afternoon
progresses. However, the upper shortwave trough axis digging across
the southern Texas Panhandle may initiate a final round of strong to
severe convection on the Southern High Plains by early evening which
could track into our southwestern CWA before weakening as it moves
into less unstable air. A few of these storms across southwest
Oklahoma and western north Texas could produce large hail and
damaging wind gusts this evening before weakening. Although not
producing any large QPF with these fast moving storms, could see
some brief localized heavy rain added to some already flooded areas
in parts southwest Oklahoma and adjacent northern Texas. Mid-level
forcing west of the troughs axis may bring some additional elevated
storms down from the Central High Plains across parts of our
northern CWA so will keep storm POPs widespread this evening across
our entire CWA although the severe risk will be much lower across
our north with any rainfall accumulations falling into less
saturated areas. Rain POPs will be ending from west to east early
Thursday morning.
Our current Flood Watch has been reduced to just 8 counties in
southwest Oklahoma and two in Texas through this evening where
additional rainfall may accumulate.
&&
.SHORT TERM...
(Thursday through Friday night)
Issued at 249 PM CDT Wed Apr 30 2025
Most of Thursday should be dry between our next upper system coming
through late in the evening into Friday morning.
For Thursday, models in agreement with consistent runs lifting the
previous days cold front across eastern Texas as a returning warm
front into our southern CWA. Although can`t completely rule out
advection fog developing Thursday morning with the increasing
surface moisture, the southeasterly surface winds will be fairly
weak keeping confidence too low to be in the forecast. Although not
full sun in the afternoon, the increasing surface moisture will
result in moderate destabilization by late afternoon up to 2000 J/kg
of SB Cape with increasing deep-layer shear toward the evening with
the next system moving in. Strong inversion capping should suppress
any late afternoon convection. However convection may start
initiating during the evening on the Oklahoma & northern Texas
Panhandles as the upper wave digs through with these storms moving
into northwestern Oklahoma by late evening and expanding further
south and east across our area overnight into early Friday. Although
much of these storms will start out elevated but could strengthen
when becoming more surface based when encountering the returning
warm front. This will result in a severe risk near and south of the
I-40 corridor on Thursday night/early Friday where the surface front
is expected to be, with large hail and damaging winds as the two
primary severe hazards.
Storms may be restricted to southern Oklahoma and western north
Texas by Friday afternoon and linger into the evening hours before
exiting overnight. However, the severe risk in the afternoon and
beyond will be much lower as instability weakens. Although parts of
our southern CWA that flooded out will see a lull through most of
Thursday, an additional couple of inches of rainfall by Friday
morning in that saturated ground could pose an additional localized
flooding risk. River flooding from the previous rainfall will also
persist across our southern CWA during the the short term period. It
will also feel unseasonably colder on Friday night with high surface
pressure building across the U.S. Northern Plains under this cooler
trough with lows in the 40s.
&&
.LONG TERM...
(Saturday through Tuesday)
Issued at 1213 AM CDT Wed Apr 30 2025
Low amplitude ridging aloft will briefly influence our weather into
the weekend before another western U.S. storm system deepens during
the Sunday/Monday timeframe with some signals of unsettled weather
for the southern Plains again by the first half of next work week.
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT Wed Apr 30 2025
Scattered showers and thunderstorms moving in from west Texas may
affect areas around KSPS and KLAW later this evening, and
potentially develop north around KCSM and KWWR as well. There are
some areas of MVFR and IFR ceilings across the eastern half of
Oklahoma, and these ceilings are expected to expand across more of
the area overnight. Some reduced visibilities will also be
possible early Thursday morning, especially at the central and
southeastern Oklahoma TAF sites.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 55 78 57 67 / 20 0 60 70
Hobart OK 51 79 55 69 / 30 0 60 60
Wichita Falls TX 54 82 57 71 / 30 0 40 80
Gage OK 46 76 50 70 / 30 10 70 40
Ponca City OK 55 77 54 71 / 20 10 50 40
Durant OK 60 83 61 73 / 20 0 40 80
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch until 1 AM CDT Thursday for OKZ034>038-044.
TX...Flood Watch until 1 AM CDT Thursday for TXZ085-086.
&&
$$
NEAR TERM...68
SHORT TERM...68
LONG TERM....24
AVIATION...26
Area Forecast Discussion
National Weather Service Pendleton OR
418 PM PDT Wed Apr 30 2025
.UPDATED AVIATION DISCUSSION...
.AVIATION...00Z TAFs...VFR conditions for all sites with light
winds and mainly clear skies. Feaster/97
&&
.PREV DISCUSSION... /issued 336 PM PDT Wed Apr 30 2025/
.SHORT TERM...Today through Friday night...
Key Messages:
1. Warming temperatures through Friday.
2. Dry conditions extend through Thursday.
3. Widespread rain and isolated thunderstorms Friday.
Current radar and visible satellite imagery showing dry conditions
as a few ribbons of high level cirrus clouds pass over the area
from the north. This is in response to the upper level ridge and
surface high pressure that continues to build in from the west-
southwest. As this ridge builds through Thursday, north flow aloft
will become more from the west and southwest through Thursday
afternoon and evening. Present high pressure coupled with more of
a southerly flow aloft component will promote high temperatures
warming about 10 degrees from today, as Thursday`s high
temperatures will reach into the upper 70s to low 80s across the
Lower Columbia Basin, Blue Mountain foothills, and Central Oregon.
High temperatures continue to climb another 5 degrees on Friday,
with values into the low to mid-80s - which is about 20 degrees
above normal for this time of year.
Present surface high pressure and upper level support will keep
skies clear and conditions dry through the remainder of the
workweek as afternoon humidities drop into the teens and 20s
across lower elevations of the Columbia Basin, Central Oregon,
John Day Basin, and Wallowa County. Conditions look to be their
driest over the John Day Basin, Hanford area, and Central Oregon
Thursday with humidities hovering in the low to mid-teens.
Overnight humidities will also be dipping into the moderate
category (50% or less) over the John Day Basin, Simcoe Highlands,
and northern Blue Mountains. Humidities look to improve Friday
afternoon/evening as an incoming system begins to impact the area
from the southwest. This will still lead to afternoon humidities
in the mid-to upper teens over portions of Central Oregon and the
John Day Basin, but excellent (71% or greater) overnight
recoveries will return Friday night into Saturday.
The approaching negatively-tilted upper level trough near the
coast and erode the present ridge to promote enhanced instability
across the area. The southerly flow aloft will also lead to an
uptick in moisture to allow for the development of isolated
thunderstorms after 1 PM. RAP and NAM guidance suggests CAPE
values between 200-300J/kg with lapse rates of 8-9C/km. Storm
development looks to focus across Deschutes, Crook, Jefferson, and
Wheeler Counties, with activity peaking between 4 PM to 9 PM. The
main concerns will reside with lightning, gusty winds, and
periods of heavy rainfall in and around storm cells. Rain amounts
on Friday should stay west of Hermiston and John Day, with
0.05-0.15" of rainfall expected across Central Oregon and
0.01-0.10" across north-central Oregon, Southern Blue Mountains,
and the Yakima/Kittitas Valleys. 75
.LONG TERM...Saturday through Wednesday...The main weather
concerns will revolve around an upper trough and cold front
crossing the area Saturday through Sunday bringing a chance of
rain and breezy to windy conditions with much cooler temperatures.
Saturday night a closed low develops in the base of the trough
and moves into central to southern California Sunday and then into
northern Arizona by Monday morning. Circulation around the low
will keep light rain showers into the eastern mountains Saturday
night and early Sunday and then a ridge will build in from the
eastern Pacific for dry and steadily warming conditions through
next Wednesday.
The Extreme Forecast Index highlights winds Saturday through Monday
with values of 0.81 to 0.91. Saturday should be the windiest day
with highlights focused on the Kittitas Valley, Columbia Gorge and
southern Blue Mountain Foothills. There is a Shift of Tails as well
indicating some model ensemble members have more extreme wind speeds
than the majority of ensemble members. Sunday shows a continued
highlight over the Kittitas Valley with a weaker signal over the
Columbia Gorge. Precipitation is highlighted Saturday over central
Oregon with a value of 0.74 and that is where moderate rain is
expected. It also highlights temperatures Saturday focused over the
Columbia Basin and Blue Mountains into Wallowa County with a value
of 0.80. It also signals warm temperatures across the entire area
next Wednesday with a value of 0.72.
Saturday will see a trough centered just off the coast sending a
deep southerly flow over our area. It will send a cold front into
the area in the morning and this will bring anywhere form a tenth to
a quarter of an inch of rain into central Oregon and the southern
Blue Mountains southward and eastward. In the afternoon, the
precipitation will cut off in central Oregon and the eastern
mountains and Blue Mountain Foothills will see the brunt of the
precipitation with up to 15 hundredths of an inch. Winds will be the
bigger story as the cold front will bring winds of 15 to 25 mph over
most of the area with the Kittitas Valley and Columbia Gorge
reaching 20 to 30 mph. Could see a wind advisory being issued for
the Kittitas Valley, but it`s too soon to have enough confidence for
that. The front will also bring much colder air and Saturday will be
anywhere from 15 to 25 degrees cooler than Friday depending on the
location. Highs will be in the mid to upper 60s in the Columbia
Basin and in the mid 50s to lower 60s elsewhere.
Sunday will see a closed low develop and move inland much to the
south of us. After circulation around the low keeps some light
showers in the eastern mountains in the morning, the low shifting
east will drag the trough out of our area and a ridge building
offshore will begin to impact our area. Temperatures will warm 2 to
5 degrees to the mid 60s to lower 70s in the Columbia Basin and to
the mid 50s to lower 60s elsewhere. Winds will be breezy but much
lighter than Saturday with the Kittitas Valley, Columbia Gorge and
central Oregon having north to northwest winds of 15 to 25 mph.
Monday and Tuesday will be fairly quiet and the ridge will warm
temperatures around 10 degrees Monday to the 70s with 60s in the
mountains and then another 3 to 7 degrees Tuesday to the mid 70s to
lower 80s with upper 60s to mid 70s in the mountains. Winds will be
lighter with winds reaching 10 to 15 mph in the afternoon. Wednesday
will likely continue this trend though models begin to have
significant timing differences with the GFS being substantially
slower than the ECMWF and Canadian about the approach of the next
upper trough. Either solution doesn`t significantly change the
forecast until after next Wednesday, so have continued dry weather
with temperatures a degree or so warmer than Tuesday. Perry/83
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 79 48 84 / 0 0 0 0
ALW 46 77 51 83 / 0 0 0 0
PSC 41 81 46 87 / 0 0 0 0
YKM 44 79 48 84 / 0 0 0 0
HRI 41 81 47 86 / 0 0 0 0
ELN 42 77 47 81 / 0 0 0 0
RDM 34 81 41 81 / 0 0 0 10
LGD 37 74 43 79 / 0 0 0 0
GCD 38 77 44 81 / 0 0 0 0
DLS 45 82 51 79 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...75
LONG TERM....83
AVIATION...97
Area Forecast Discussion
National Weather Service Reno NV
149 PM PDT Wed Apr 30 2025
.KEY MESSAGES...
* Showers and thunderstorms are expected to continue today,
particularly south of US-50.
* Seasonably mild weather continues through Friday with high
temperatures 5-10 degrees above season averages.
* Increasing chances for a spring storm are in the forecast to
bring back colder weather, breezy winds, and more rain/snow
chances this weekend.
&&
.DISCUSSION...
Upon looking at the latest RAP upper air analysis, the CWA is
underneath a positively tilted upper trough with a ridge trailing it
just off the Pacific coast. The latest satellite and radar imagery
reports that southern half of the CWA especially in Mono and
Mineral Counties have showers and thunderstorms ongoing already
today. Forecast guidance shows the upper trough sliding to the
southeast and cutting off into a low over SoCal as the trailing
ridge moves over the PacNW tomorrow. This ridge is projected to
continue an eastward trek on Friday followed by a large trough
moving into the PacNW giving the CWA a southerly upper air flow by
the Friday night hours. As the trough progresses over the Western
CONUS on Saturday, a cutoff low forms over Central CA late in the
day that travels in a east-southeast direction and to the south
of the CWA on Sunday.
At the surface, models still show precipitation chances today to be
the best along and south of US-50 this afternoon and evening with
Mono County seeing the highest probability with a 60-70% chance.
Showers have around 30-40% chance to contain thunder today.
Potential hazards with thunderstorms occurring today include
gusty outflow winds up to around 45 mph, moderate to heavy
rainfall, and frequent lightning strikes. Models show precipitation
chances tapering off to the south and end completely around
midnight tonight. QPF values from the showers and thunderstorms
today range from a trace to around 0.4 inches around Crowley Lake.
Chances for showers and isolated thunderstorms around 15-25% are
seen once again on Thursday afternoon down in Mono County while
the rest of the region stays mostly dry.
The warming trend is expected to continue at least through
Friday. Portions of Western NV like those around Fallon see a
70-80% chance of high temperatures on Friday of 80 degrees or
greater. But Friday`s highs in the lower valleys warm to around 70
to 80 degrees while the Sierra Mountain communities will be in
the 60s. However, the weekend system will cause the temperatures
to get cooler. The Western NV valleys have daytime highs dropping
to the middle 50s to lower 60s on Saturday and then into the lower
to upper 50s on Sunday. Sierra Mountain communities may see highs
in the 40s and 50s on tap for this weekend with the expected
wintry system moving through.
Forecast guidance shows that precipitation chances becoming a bit
more widespread in coverage beginning Friday and going into the
weekend. Thunderstorm chances (15-30%) are seen once again along
and west of the CA/NV border during Friday afternoon and evening.
Snow levels do look to stay above 9 kft for Friday before they
decrease down to 6.5-7 kft by Saturday evening. The main story
for the weekend continues to be another round of mountain snow and
valley rain along with low pressure moving through the region.
When looking at the latest NBM probabilities for Saturday and
Sunday, there is now a 40-50% chance for 5+ inches of snow in
higher elevations of Mono County (which has come up a bit since
yesterday) though low confidence in snowfall totals continues. The
latest probabilistic Winter Storm Severity Index now displays a
10-30% chance of moderate impacts for the Eastern Sierra
Mountains around pass level, so will continue to monitor this as
well as roads and surfaces could become slick with snow. -078
&&
.AVIATION...
Thunderstorms will be the primary concern this afternoon and evening
for all regional terminals, but especially for KCXP, KMEV, KTVL, and
KMMH where there is 20-40% chance of a thunderstorm within 10 miles
of these terminals through 03Z. There`s greater uncertainty of
thunderstorm potential at KTRK and KRNO, although an isolated storm
is possible (10-20% chance) until around 23Z before drifting
southward away from each respective site. Strongest thunderstorms
will be capable of brief downpours/MVFR conditions, gusty and
erratic winds, small hail, and lightning. Otherwise, occasional rain
showers may yield MVFR conditions and mountain obscuration into the
early evening with breezy N/NE winds this afternoon.
-Salas
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$