Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/05/25
Area Forecast Discussion
National Weather Service Burlington VT
1033 PM EDT Sun May 4 2025
.SYNOPSIS...
Cool and unsettled weather continues through early this upcoming
week across the North Country, with additional showers likely and
temperatures slightly below normal. The highest probability of
precipitation and heaviest rainfall amounts tonight into Monday will
be across Rutland and Windsor counties, localized amounts greater
than 1 inch are possible. Very little rainfall is expected near the
International Border. Temperatures only cool into the mid 40s to mid
50s tonight and highs in the mid 50s to mid 60s on Monday.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1033 PM EDT Sunday...Forecast remains in good shape. Went
ahead to tighten the northern extent of higher PoPs given radar
trends, with the shield of rain not getting quite as far north
at it appeared poised a few hours ago and since retreating.
Temperatures amidst light winds and thin high clouds in much of
our region are settling slightly cooler than forecast in many
locations but no substantial differences are anticipated moving
through the night.
Previous Discussion...
Fcst challenge is pops and amount of qpf over the next 12 to 24
hours as a closed cyclonic circulation remains parked over the
Ohio Valley. These deep closed 7h/5h circulations always present
challenges with regards to pop timing and precip amounts and
the potential for flooding needs to be monitored closely over
the next couple of days.
RAP UA and GOES-19 water vapor shows a closed and vertically stacked
system over the Ohio Valley with deep rich moist conveyor belt acrs
the eastern seaboard into central PA. The combination of strong ulvl
divergence in the hght fields and rrq of 250mb jet is helping with
deep synoptic scale ascent and associated cooling cloud tops over
central/eastern PA/NJ attm. Meanwhile, strong high pres and
associated deep dry layer with pw values <0.30" is trying to push
south toward our northern cwa. Guidance consensus supports mean 850
to 500mb RH proggs <30% near the International Border by 00z this
evening, while pw values are surging northward over southern VT with
a sharpening moisture gradient. In addition, to deep layer moisture
advection, areas of enhanced mid lvl frontogenesis and mid lvl
deformation is lingering acrs Rutland/Windsor counties tonight. This
synoptic scale ascent wl interact with a lingering stationary
boundary over southern New England to produce periods of rain
overnight into Monday. Rainfall amounts will be between 0.50 and
1.0" with localized higher amounts possible on the favorable
southeast upslope areas of eastern Rutland/western Windsor counties.
HREF prob of qpf >1.0" is near 100% along and south of Route 4,
while prob of 2.0" or greater is south of our cwa. A strong/tight
north to south qpf/pop gradient is anticipated with very little near
the Border. I have pops near 100% south and <10% north tonight into
Monday.
By midday Monday deeper moisture is lifting back northward acrs our
central cwa, along with another axis of favorable 700mb
frontogenesis. Expecting rain shower activity to expand northward
midday Monday, especially as 925mb to 850mb southeast jet of 35 to
45 knot strengthens and helps to enhance better llvl moisture
convergence. Some downslope shadowing is likely along the western
slopes, along with localized gusts 20 to 30 knots, especially toward
00z Tues. Given the lack of instability tonight and Monday, feel
rainfall rates should limit any potential flooding, but we always
have to watch these deep and slow moving closed systems. Highs on
Monday wl once again be influenced by clouds with warmest values
north and coolest south, where clouds/precip are the most likely.
Generally highs in the mid 50s to mid/upper 60s acrs our fa.
Additional moisture and lift rotate from south to north acrs our cwa
on Monday night with more showers likely. Greatest concentration and
highest pops wl be in favorable southeast upslope areas, as 925mb
southeast jet strengthens to 40 to 45 knots overnight. Lows very
similar to previous couple of nights, mainly 50s.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 326 PM EDT Sunday...Our friend the upper-level low will finally
begin to move to the northeast as blocking in the Atlantic breaks
down Tuesday. The low- level jet will continue Tuesday morning across
the mountain peaks, with gusts nearing 45 knots. Due to the
inversion, mixing towards the valleys should be limited, but
locations immediately west of the Greens and Adirondacks above 2000
ft could see continued gusty winds Tuesday morning, before calming
into Tuesday afternoon. The axis of moisture along the warm conveyor
belt will begin to surge northward with more widespread
precipitation likely across south-central Vermont during the day
Tuesday. In the areas under the moisture axis, QPF amounts between a
quarter to half an inch of rain is possible between Tuesday and
Wednesday. NBM 24-hr probabilities of 0.5 inches in southern Vermont
Tuesday into Wednesday are between 30- 50%, with higher amounts in
southern/eastern New England. Depending on the exact track of the
low, higher precipitation could slide north/west into our region, as
CAMs are suggesting. We will continue to monitor trends as the
system draws closer. As the center of the low tracks into the St.
Lawrence Valley by Tuesday afternoon, underneath the low,
instability will increase with SBCAPE mean values between 200-400
J/kg. Some scattered convection is possible Tuesday afternoon in
portions of St. Lawrence County, but should quickly dissipate
overnight Tuesday as clouds and mid-level warming increase,
decreasing the instability.
By Wednesday, light shower activity continues under south-
southeasterly flow. Like Tuesday afternoon, underneath the low,
marginal instability could build by the afternoon, with widespread
slight chances for thunderstorms. Temperatures will be heavily
dependent on any cloud cover that develops with any showers. With
any breaks and sunshine, 925hPa temperatures are around 10-12 C,
meaning 60s to 70s for highs both days are expected. Tuesdays low
will be relatively mild with values in the 50s across the valleys
and upper 40s for the higher terrain.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 326 PM EDT Sunday...The main upper low finally begins to move
out of the region Wednesday night as the overarching trough swings
to the east. However, as the low exits, a surface cold front will
push into the area with lingering rain chances again. Temperatures
Wednesday night will be seasonably chilly in the 40s. Following the
front, temperatures quickly rebound back into the upper 60s for the
weekend with lows in the 40s. New guidance suggests a lower chance
of any frost/freeze potential Friday and Saturday morning from
previous guidance. Just as we think the precipitation might finally
be clear, another upper low looks poised to develop Thursday into
Friday across the Mid-Atlantic. Models are in disagreement on the
track and timing of this system. One solution shows a more
progressive low moving into the Gulf of Maine by Saturday with
little precipitation chances for the weekend, outside of portions of
the Northeast Kingdom. Another solution indicates a slower moving
system that retrogrades back into our region Saturday into Sunday,
making for yet another wet weekend. NBM probabilities of
precipitation still show near 20% overall, however, the trend has
been towards increased chances of rain for sun lovers. If you were
hoping for a completely dry weekend, it still is in play, but
chances are quickly diminishing.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Through 00Z Tuesday...Largely a persistent forecast in the next
6 to 12 hours with a stagnant pattern. However, just enough of a
low level easterly flow has developed just above the ground to
scour out the low ceilings at RUT. In contrast, this easterly
wind will also lead to ceilings lowering at other sites with
MVFR conditions favored at MPV, and perhaps even PBG by late in
the day, as moisture increases amongst widely scattered
showers. This rain will overspread portions of the region,
generally south and west of BTV, after 12Z moving in from the
south. Precipitation should be light in intensity and move
towards the north-northwest in a somewhat uncommon direction.
A substantial increase in the easterly flow aloft should
result in turbulence and shear near RUT overnight into Monday.
Surface winds there should increase substantially during the day
with 12 to 18 knot sustained winds expected out of the
southeast. Elsewhere, lighter southeast winds are expected,
except northeasterly winds at MSS which should trend gusty
especially between 06 and 18Z, then easterly and lighter.
Outlook...
Monday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Tuesday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Tuesday Night: Mainly MVFR, with local IFR possible. Chance SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA,
Slight chance TSRA.
Wednesday Night: Mainly MVFR, with areas IFR possible. Chance
SHRA.
Thursday: Mainly MVFR, with local IFR possible. Chance SHRA.
Thursday Night: Mainly MVFR, with local IFR possible. Slight
chance SHRA.
Friday: Mainly MVFR, with areas VFR possible. Slight chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Kutikoff/Taber
SHORT TERM...Danzig
LONG TERM...Danzig
AVIATION...Kutikoff/Taber
Area Forecast Discussion
National Weather Service Charleston SC
1007 PM EDT Sun May 4 2025
.SYNOPSIS...
A cold front will linger nearby before shifting offshore on
Monday. Thereafter, high pressure will build in again from the
west. A cold front and an upper level low will approach the
region from the west Thursday. The unsettled weather pattern
will then persist into next weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Late this evening, a slow moving cold front and a sea breeze
continued to drift over the forecast area. Isolated showers and
thunderstorm have triggered along the boundaries this evening.
Recent runs of the HRRR indicates that convection may develop
near the SC coast through late tonight. The forecast will
continue to indicate SCHC to CHC PoPs through late tonight.
Skies begin to clear during the early morning hours, with a low
chance (<10%) of some light fog forming across areas of the
Lowcountry that receive rainfall this afternoon evening.
Temperatures are expected to be noticeably cooler than the last
few nights with low to mid 50s inland and mid to upper 50s along
the coast.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Monday: With closed upper-lvl low situated over the Bluegrass
region and a secondary upper-lvl low located near the California
coastline, this omega blocking pattern will continue dominate
the CONUS. At the surface, the cold front will be offshore by
daybreak, though post-frontal CAA will be very limited beyond
some milder dew points. Ample sunshine through the day with high
near to a few degrees above normal. Continued dry conditions
under strengthening mid level ridge continues overnight, with
cooler temperatures into the mid 50s inland and low to mid 60s
along the coast.
Tuesday: This omega blocking pattern will begin to finally
break down as the closed upper-lvl low begins to move slightly
further away. Mid level ridge axis moves overhead during the
day, with dry conditions persisting into the night despite the
onset of very modest height falls aloft. Very weak gradient will
ensure that the sea breeze is the dominate surface feature, with
temps reaching the mid to upper 80s ahead of the sea breeze
front. Modest WAA ensues later in the day with low Tuesday night
returning to near-normal.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A decaying omega block will be over the Ohio River Valley on
Wednesday with two closed upper level lows located across the United
States. The first closed low will be located over New England, with
the second closed low located just east of the Four Corners region.
Global ensemble guidance is actually in fairly good agreement with
the progression of these two closed lows Wednesday through Friday.
All three of the GEFS/ GEPS/ and EPS show the closed low that was
east of the Four Corners region moving east towards the Southern
Mississippi River Valley with a strong upper level shortwave over
New England. Taking a look at the WPC Cluster Analysis though, does
reveal some important differences and highlights the inherent
uncertainty when dealing with closed lows that are broken off from
the main longwave pattern. In particular, most of the ensemble
differences appear to be with the first closed low and how it ejects
northeast towards New England. How the low ejects (or gets absorbed
back into the main longwave pattern), appears to be where the
uncertainty originates from (further supported by the WPC Ensemble
Sensitivity Analysis -- WESA webpage). About 60% of the guidance is
showing a slower exit of the first wave, with about the other 40% of
guidance showing a quicker exit of the first wave. What does this
mean locally?
Scenario 1 (slower exit of the closed upper level lows): At this
point, the slower exit of the first and then second closed low is
slightly favored. This does make synoptic sense, since the second
closed low actually tends to develop a weak rex block at it moves
across the central United States. The slower solution would make for
a slightly delayed onset of showers and thunderstorms, but for a
threat of heavier rainfall for Thursday through Saturday (multiple
rounds of showers and thunderstorms). A cold front would then stall
across the region late Saturday with a closed low located southwest
of the region. This would provide more than sufficient upper level
lift to the region.
Scenario 2 (faster exit of the first and second closed low): This
solution is not as favored, but would still bring several rounds of
showers and thunderstorms to the region. The second closed low would
eject back into the longwave pattern by Saturday and Sunday though.
This means showers and thunderstorms would start Wednesday, but come
to an end quicker/ over the weekend. This solution is also slightly
more of an amplified wave pattern which would push the front through
the region. Box and whisker plots of this cluster, clearly shows
this with low temperatures a good 5 to 10 degrees cooler Sunday
compared to scenario 1.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Prior to the 0Z TAFs, KCLX and sfc observations showed a slowing
sea breeze generally over the I-95 corridor. Isolated to
scattered showers and thunderstorms should develop along the
boundary through much of this evening. It appears the KCHS will
see the greatest chance for convection, highlighted with a
mention of VCSH until 2Z. By late tonight, a weak cold front
should drift across the terminals, resulting in light winds
to shift from the SW. Southwest winds should strengthen by early
Monday afternoon, with gusts around 20 kts at KCHS and KJZI.
Extended Aviation Outlook:
Wednesday through Friday: Multiple rounds of showers and
thunderstorms are expected through the period as an upper level
low approaches from the west. Simultaneously, a cold front will
potentially stall near the area late Friday into Saturday.
Periods of MVFR/ IFR conditions are possible at all terminals.
&&
.MARINE...
tonight: Southwest flow is expected to mostly be in the 10-15
knot range today, with gusts up to around 20 knots possible. The
front will shift through the waters after midnight which will
turn winds northwesterly, though with speeds generally no more
than 10 knots. Seas are expected to average 3-4 feet today, then
2-3 feet overnight. Thunderstorms will likely move through
portions of the waters through the day and overnight. These
storms will be capable of producing strong wind gusts and
frequent lightning.
Monday - Tuesday: High pressure ridging in from the west behind
the departing cold front will keep a weak gradient and
relatively favorable marine conditions in place both days with
slightly gusty conditions only nearshore as the afternoon sea
breeze develops.
Wednesday - Thursday: Seas will generally be 2 to 4 ft with winds
out of the south at 10 kt. A slight backing in the winds can be
expected Wednesday as a sea breeze potentially develops. Multiple
rounds of showers and thunderstorms are likely (60 - 80%) through
the period.
Friday: An upper level low will approach from the west and north
with the pressure gradient tightening over the marine zones. Out
ahead of a cold front, winds will back from the northeast and
increase 10 to 15 kt. Gusts up to 20 kt with seas building 3 to 4 ft
possible. As winds increase out of the northeast, a 9 to 10s period
will be introduced. As of current, no small craft advisories are
forecast. Multiple rounds (80%) of showers and thunderstorms are
expected though.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...CEB
LONG TERM...BSH
AVIATION...NED
MARINE...BSH/CEB
Area Forecast Discussion
National Weather Service State College PA
1056 PM EDT Sun May 4 2025
.SYNOPSIS...
* Monday and Tuesday will feature multiple additional bands of
moderate to heavy rainfall from showers and thunderstorms.
* Becoming drier late in the week with a trend toward below
normal temperatures.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 0200z Monday, satellite and radar trends showed deep
convection focused across the western 1/3 of PA, in the vicinity
of an occluded front. With the loss of daytime heating and
farther away from the sfc boundary, any pop up convection across
central PA overnight will likely be non-severe (isolated rain
showers for the most part). Low clouds and patchy fog/drizzle
will develop from north to south across much of the area.
Another mild night is in store with lows around +15F compared to
normal.
The deep/vertically stacked low in the Ohio Valley will
continue to influence our weather pattern to start off the work
week. A few stronger storms are possible over any portion of the
CWA Monday afternoon thanks to the combination of marginal
instability, sufficient shear, steepening mid-level lapse rates,
and increasing divergence aloft. Convective mode will likely
be scattered discrete cells during the afternoon, growing
upscale into clusters and lines by the evening. Given the flow
around the large upper low, expect storm motions of SE to NW
with right- propagating storms moving due north. SPC maintains a
MRGL risk for stronger updrafts containing 1 inch hail and
locally damaging wind gusts. Although not outlooked for
tornadoes, a brief, weak tornado can not be ruled out given the
low LCLs and sufficient veering of the wind profile at low
levels.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Convection may be slow to wane Monday night, with both the NAM
and HRRR showing potential for narrow swaths of 1-2" of
rain falling from mature convective lines and clusters in just
the 12 hour period from 00z-12z Tue.
While rainfall will generally be beneficial and bring some
relief to drought conditions particularly in the southeast part
of the forecast area, we will need to closely monitor for
potential areas where repeated rounds of heavy rainfall could
result in localized flooding of urban and poor drainage areas.
WPC has maintained a marginal excessive rain risk for Monday -
Monday night.
Active weather will likely continue into Tuesday as the core of
the upper low moves into western PA. This will push the highest
instability and greatest chance for severe weather east into
the Lower Susquehanna Valley.
The threat for severe weather appears to decrease Wednesday as
the slow moving upper low gradually fills in and the center
moves east of the area, with precip likely coming to an end by Wed
evening.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
By the latter half of the week, the upper low will be replaced
by a fairly potent upper trough as high pressure builds in at
the surface. Much lower PWATs (0.25 - 0.75") will usher in a
stretch of cooler and less-rainy conditions for the weekend.
Cool temps aloft will keep a chance for diurnal showers in the
forecast each afternoon, but ensemble mean rainfall for the
period is less than a quarter inch across the whole area.
High pressure amidst a cooler airmass will support a risk for
frost Friday and Saturday morning, especially west of I-99 and
north of I-80. The growing season is currently active for only
the counties along/east of I-99 and along/south of I-80, but as
we approach the median date of the first freeze for much of the
Laurel Highlands and northwest mountains (May 11th),
Frost/Freeze products may be needed there later this week.
After the brief cool snap Thursday night through Friday night,
ensembles favor a return to near normal temperatures with highs
in the 60s to 70s and lows in the 40s to 50s.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Low stratus is building across north central PA this evening
and is expected to continue expanding southward overnight, along
with the development of patchy fog. Isolated heavy downpours
will also remain possible. Winds will maintain an easterly
component at or below 10 knots through the night.
Another round of showers and thunderstorms will develop during
the day Monday with some storms capable of producing large hail
and gusty winds. Convection will likely reach peak coverage
during the early evening hours.
Outlook...
Tue...Frequent rain showers; some locally heavy with prolonged
sub-VFR conditions. Chance of TSRA/CB.
Wed-Fri...Showers become more scattered with higher chances in
the afternoon/evening hours. Restrictions possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/Banghoff
NEAR TERM...Colbert
SHORT TERM...Lambert/Banghoff/Colbert
LONG TERM...Banghoff
AVIATION...Guseman/Colbert
Area Forecast Discussion
National Weather Service Gray ME
1100 PM EDT Sun May 4 2025
.SYNOPSIS...
A stationary front lingers nearby through the overnight,
bringing more rounds of showers through tomorrow. With a cut off
low pressure remaining in the Ohio Valley, unsettled conditions
continue into early this week with continued chances of rain
and showers.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
11 PM...Going forecast is in good shape at this hour and have
mainly refined PoPs based on latest radar trends. Band of rain
stretching west to east across the southern half of the forecast
area will slowly shift south through the rest of tonight.
630 PM Update...Surface obs show a stationary front draped west
to east just south of the NH/MA border with winds primarily out
of the NE across the forecast area. Farther north drier air is
attempting to push south of the Canadian Border. Current radar
shows an axis of light to moderate rain across much of New
Hampshire south of the Whites through the coastal plain of
Maine. Recent runs of the HRRR suggest the stationary front will
not move much tonight with rain likely continuing across
southern NH into far SW Maine while the northern edge of rain
across central Maine will push south overnight. Have mainly
refined PoPs to better align with observed trends and recent hi
res guidance.
Previously...
The next batch of showers and a few embedded thunderstorms
continues to develop and move in from the southwest this
afternoon. At the same time, a steadier area of light rain
continues to press southward from the Canadian border as high
pressure builds in from the north. Waves of moisture continue to
move along a stalled frontal boundary through the overnight
hours. Northern areas stand the best chance to dry out through
the evening and overnight as the high builds southward, as
central and southern areas continue to see more rounds of
showers.
Some heavier rainfall is likely across southern New Hampshire,
especially southwestern New Hampshire. Here, 1-2" of rain is
likely through the overnight with some locally higher amounts
possible. Amounts drop off quickly to the north from here, with
amounts down to around a tenth to a quarter inch through central
Maine and New Hampshire.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Showers continue for central New Hampshire and southern areas
tomorrow as waves of moisture continue to pivot in from the
upper level low. However, northern areas likely see more
sunshine and the warmest temperatures, with highs into the low
60s through northern locations and into central Maine. Southern
areas remain confined to the low to mid 50s with clouds,
showers, and a steady east wind.
Very little changes with the pattern by tomorrow night as the
high only slowly moves eastward into Atlantic Canada, allowing
more moisture to move in through the overnight hours. While it
isn`t raining at all times, waves of showers likely increase
again late into the overnight as they rotate in from the
southeast. Lows look pretty uniform across the forecast areas in
the mid to upper 40s as cloud cover spreads back northward.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
11 PM Update...No major changes within the latest NBM guidance
for the second half of this week. The overall theme will be for
shower chances to decrease each day as one upper low exits mid
week, while troughing will linger near the East Coast into the
weekend.
Previously...
Key Message: Unsettled weather continues for the foreseeable
future. Best bet for drier weather will not return until late in
the week.
Impacts: Depending on what areas get hit hardest by rain...if
repeats over the same areas there could be a gradually increase
in flood threat.
Forecast Details: Upper low over the OH Valley will drift east
and begin to fill by midweek. By Tue the moisture feed will
sweep across New England. This is probably out best chance for
steady rainfall and I have categorical PoP for much of the area.
After that we fall under the influence of the departing upper
low. The cool temps aloft will lend themselves towards diurnal
increase in shower activity. After the Wed period there is more
uncertainty in the forecast. Model guidance favors another upper
low developing and cutting off in the vicinity of the Northeast
for the late week into the weekend. These cut off lows are
notoriously hard to pin down...but it does warrant at least some
PoP thru the extended forecast.
As for temps...there does not appear to much space between all
the showery weather for sustained warmth. We may be able to
approach the 70s on the transition day between systems...but
otherwise look to remain largely in the 50s and 60s. Not cold by
any means...but not above normal during the day. Our best shot
at above normal temps will come overnight...where plenty of
clouds and precip will keep readings on the warmer side.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Short Term...IFR to MVFR ceilings prevail through tomorrow
morning at most terminals with showers, and some fog possible
overnight along the coast. Some VFR conditions are possible at
AUG, RKD, and HIE by late tomorrow morning, with MVFR to IFR
conditions elsewhere with showers. Ceilings then lower again
tomorrow night, with IFR likely returning to all terminals with
showers.
Long Term...Not much change in the forecast is expected thru the
end of the week. Confidence is higher thru midweek...where
conditions will be similar each day. IFR or lower conditions
will be possible at night...especially near the coast...with
some minor improvement to MVFR in areas during the day away from
the coast. Precip will be most likely on Tue. The latter half of
the week carries more uncertainty. It could be very similar to
current conditions...or we could get lucky and the upper low
cuts off farther away and allows for some improvement.
&&
.MARINE...
Short Term...High pressure remains north of the waters, as low
pressure remains off to the south. A freshening east wind
develops during the day tomorrow, with conditions remaining
below SCA levels through at least tomorrow night. Areas of dense
fog are likely to continue into tomorrow.
Long Term...Winds and seas generally expected to remain below
SCA thresholds thru the extended. Slow moving upper low may
bring an extended period of onshore flow and seas may build to
near 5 ft well outside the bays around midweek. Otherwise the
main hazard will be periods of showers with low visibility and
areas of fog.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM...Clair/Schroeter
SHORT TERM...Clair
LONG TERM...Legro/Schroeter
Area Forecast Discussion
National Weather Service Omaha/Valley NE
616 PM CDT Sun May 4 2025
.KEY MESSAGES...
- Enjoyable weather continues this afternoon with comfortable temperatures
under mostly sunny skies. Winds may be breezy across the far
northwest. Similar conditions expected Monday.
- PoPs increase late Tuesday across the far south (15-20%) and become
widespread Wednesday (20-50%) before exiting Thursday. Only
expecting a few hundredths of an inch for rain. Severe weather
is not expected.
- Temperatures warm toward the end of the work week into the
weekend with little to no PoP threat.
&&
.DISCUSSION...
Issued at 230 PM CDT Sun May 4 2025
.SHORT TERM.../Today through Monday Night/
RAP objective analysis depicts the omega pattern nicely at 300 mb
this afternoon with two notable PV anomalies: one over southern
California and the second over the Kentucky/Tennessee area where the
closed lows are based. Much of the Northern and Central Plains
continue to be sandwiched in between these features with an upper
level high seen over the Dakotas/Minnesota. Closer to home, 19z RAP
sfc analysis shows the high just to our east, with the ridge axis
over central Iowa southwestward into Missouri and eastern Kansas.
The aforementioned sfc high is resulting in our pleasant
weather conditions for this afternoon, aside from some breezy
southeasterly winds in the far northwest where a tighter
pressure gradient and boundary layer mixing into stronger 850 mb
flow is observed. These factors will lead to 15-25 mph gusts
northwest of a line from Albion to Norfolk to Wayne. Otherwise,
expect high temperatures today to reach the low to mid 70s under
mostly sunny skies. Lows tonight will be in the mid 40s, warmer
than yesterday`s lows due to southerly 850 mb flow.
Monday will still see some influence of the sfc high across our
service area with mostly sunny skies expected and some breezy
southeasterly winds over our far northwest again. Highs will be in
the mid 70s areawide and may reach 80F over our far northwest. Lows
will be in the mid 40s with cloud cover steadily increasing late
Monday evening ahead of an approaching system.
.LONG TERM.../Tuesday through Saturday/
The 500 mb closed low and associated vorticity lobe over southern
California will finally eject and move northeastward toward the
Central Plains during the day Tuesday. Although weak, low to mid
level moisture return results in increasing cloud cover throughout
the day despite highs reaching the upper 70s to low 80s thanks to a
weak 850 mb thermal ridge. Synoptic scale Q-vectors indicate
convergence overspreading much of the forecast area by Wednesday,
although the best kinematic forcing appears to be closer toward the
Nebraska/Kansas border. NBM does show PoPs (15-20%) returning late
Tuesday evening, but the best low to mid level moisture transport
doesn`t arrive until Wednesday. BUFKIT soundings also confirm this
with the best deep layer saturation observed mainly along and south
of Interstate 80. This results in NBM bringing 20 to 50% PoP chances
by Wednesday afternoon, with highs a tad cooler than Tuesday.
Mid-level forcing lingers into Thursday as do PoPs with a 20-40%
chance along and south of Interstate 80. PoP chances end by Thursday
evening as the 500 mb low over eastern Kansas and western Missouri
dives southeastward. As far as rainfall/QPF amounts, only a few
hundredths of an inch are expected so will certainly not be a
drought buster. A few hundred J/kg of MUCAPE is seen during the
afternoon and evening hours Wednesday from model soundings, so
some thunder is certainly plausible, but not expecting to see
severe weather.
With the closed low diving southeastward, ridging again builds over
the western CONUS and moves eastward as we head into the weekend.
This will help keep us dry with NBM showing unmentionable PoPs at
this time. Temperatures will warm again starting Friday as the 1000-
500 mb thermal ridge tracks eastward into the Northern and Central
Plains, with highs in the mid 70s to near 80F. Saturday appears to
be the warmest day with widespread upper 70s and low 80s across the
OAX forecast area.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 614 PM CDT Sun May 4 2025
VFR conditions will prevail through the forecast period with
little to no cloudiness. Winds will remain from the east or
southeast at less than 12 kt.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Castillo/Mead
AVIATION...Mead
Area Forecast Discussion
National Weather Service Pueblo CO
615 PM MDT Sun May 4 2025
.KEY MESSAGES...
- Widespread showers and thunderstorms over the mountains
tonight, while more scattered activity spreads northward
across the plains.
- A wave of showers will move through the area Mon morning, then
a stronger wave with widespread showers/thunderstorms expected
in the afternoon with pockets of heavy rainfall possible.
- Periods of heavy rainfall possible through Wednesday across
southern Colorado along with cooler temperatures. Snow for
areas above 10k feet.
- Warming trend returns starting Thursday.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 205 PM MDT Sun May 4 2025
Upper low over srn California this afternoon, with diffluent sly flow
across Colorado. Shower and thunderstorm activity was increasing in
coverage/intensity over the mountains/interior valleys at mid-
afternoon, though storms have yet to make much progress past I-25
onto the plains is currently promoting a n-nw storm motion. For the
remainder of the afternoon and evening, best forcing for convection
will continue over the mountains/valleys, with rounds of showers and
thunderstorms moving northward through the period. Along I-25 and
across the plains, CAMs suggest at least scattered activity will
develop as air mass becomes moderately unstable, with least chance
for storms father east toward the KS border. After midnight, main
focus for precip appears to stay mainly south along the NM border,
though expect at least occasional showers to spill northward across
the area into Mon morning. Snow levels overnight will stay in the 9k-
10k foot range, with several inches of accumulation possible over
the higher peaks of the ern San Juans by sunrise.
On Monday, upper low trudges slowly eastward through AZ, as very
blocky upper level pattern continues. HRRR and NAM suggest an initial
wave of showers lifting northward through the area in the morning,
before more substantial energy ejects from the low in the afternoon,
leading to a period of widespread showers and thunderstorms.
Heaviest precip would appear to focused on the srn slopes of Pikes
Peak where orographic flow is most favorable, with some pockets of
heavy precip also possible over the nrn Sangres/Wets and Fremont
County. Given this is the first round of heavier rain and the fact
that precip will be moving northward fairly quickly (15-25 kts),
won`t be issuing any flood highlights at this point, as streams and
soil across the area will have the capacity to absorb a good deal of
rainfall. While SWODY1 has marginal risk nosing into Las Animas
County, suspect clouds and showers may limit instability and storm
strength through the day, keeping any severe threat low-end and
brief. Snow level will continue to hang out in the 9k-10kt foot
range, and with current QPF supporting significant accumulations
over many mountain peaks, will start a long-running Winter Storm
Warning for Pikes Peak and the higher portions of the Sangres/Wets
at 18z. Clouds/precip will keep max temps cool, with mainly 50s
lower elevations, 40s in the mountains.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 205 PM MDT Sun May 4 2025
Models are doubling down on a potent Spring storm system to affect
the region through Wednesday, bringing widespread heavy rainfall and
significant new snow to the mt peaks.
Monday night...Upper low tracks from the Four Corners into northern
NM Monday evening, with persistent rain and storms across the
eastern mts and plains through midnight. SPC kept the Marginal area
for severe storms up along the I-25 Corridor, and according to the
NAM best CAPE and shear will be in the 5 PM to 8 PM timeframe. Feel
that there may be stronger storms for a brief period, producing
rounds of heavy rainfall and perhaps sub-severe hail. Models as well
as WPC have really hit the QPF hard, and even with some moderation
on this end total storm QPF as well as potential snowfall has ramped
up. Decided to go ahead and issue a Winter Storm Warning for the
peaks of the eastern mts since the most significant snow looks like
it will accumulate from 10k feet up.
Tuesday...Another lobe of energy rotates around the low as it edges
north to the CO and NM state line. Tue still looks to be the wettest
day for the eastern mts and eastern plains, with significant new
snowfall for the mts adding up after a brief lull in the morning.
Precipitation chances have been increased to categorical across all
of the eastern plains, and SPC has placed the entirety of CO under
the General thunder area. Slow moving thunderstorms, if they
develop, will need to be monitored closely Tue for potential
flooding threat.
Wednesday...Upper low finally starts to push east, moving into KS by
early evening. Widespread showers and isolated thunderstorms will
persist through midday, then begin to diminish from west to east
through the night.
Total QPF amounts through this entire system comes in around 1.5 to
2.5 inches of liquid for much of the plains, but the eastern slopes
may see as much as 3 inches of liquid through this 4 day timeframe.
If any thunderstorms do develop and track slowly across an area,
rapid accumulation will become a concern, especially on Tue when the
ground will be more saturated from pcpn on previous days.
As for temps, plan on daytime high temps in the upper 40s to upper
50s due to the expected cloud cover and ongoing precipitation.
Overnight lows will dip into the upper 20s to around freezing for
the high valleys, and mid 30s to mid 40s for the plains. There is
the possibility of some frost pockets Tue night and again Wed
night across the plains.
Thursday through Saturday...Upper ridge builds in across the region
as the previous system exits to the east. Moisture trapped under the
ridge will help initiate a daily shot of afternoon and evening mt
convection. Temps will be on the rebound as well, warming into the
60s for most areas on Thu, then for Fri and Sat the 60s to near 70F
for the high valleys, and mid 60s to mid 70s for the plains.
Sunday...Upper ridge axis starts to slide east, with an increasing
southwest flow aloft expected. Moisture advection will be on the
upswing, with mountain convection likely with scattered activity
spilling across the I-25 Corridor. Temps will continue warming,
nearing 70F for the high valleys and nearing 80F across the
plains. Moore
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 607 PM MDT Sun May 4 2025
Upper low across the Desert SW will continue to spin waves
across the region through the taf period, with one wave moving
across southern Colorado attm. This will keep chances of showers
and thunderstorms at COS, PUB and ALS with brief MVFR conditions
possible through 06Z Mon. There could be a break in precipitation
chances through 12Z, though east to southeast upslope flow will
lower cigs to MVFR and IFR conditions through the overnight
hours at the terminals, with chances of showers and
thunderstorms increasing once again through the late morning
and afternoon, as another wave of energy lifts out across
southern Colorado.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM MDT Tuesday for COZ060-066-
068.
Winter Storm Warning from noon Monday to 6 AM MDT Wednesday
for COZ073-075-080-082.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...MW
Area Forecast Discussion
National Weather Service Las Vegas NV
637 PM PDT Sun May 4 2025
.SYNOPSIS...Showers, thunderstorms, and much cooler than normal
temperatures will persist through Monday for much of the area as a
strong storm system continues to impact the area. Beyond Monday,
we will see a drying and warming trend through the next week,
with temperatures well above normal by the end of the week.
&&
.UPDATE...In general, the HRRR performed well today regarding the
location of convection, but the intensity was overdone, compared to
what came to fruition. Anomalous moisture in the region allowed for
rain rates across south-central Mohave and San Bernardino counties
to peak between 0.25 and 0.35 inches per 15 minutes at times.
Earlier in the afternoon, storm motion was quick enough that flash
flooding was not expected. However, as the afternoon progressed -
particularly across our southern zones that are closer to the center
of the low - storm movement halted to 5 mph or slower, which
resulted in flash flooding along State Route 62 in southeastern San
Bernardino as well as along local roads west of Barstow. Forecast
HRRR reflectivity continues to highlight Inyo County for late-
afternoon into early-evening convection. The RAP is highlighting a
region of increased instability in southern Inyo County and northern
San Bernardino County over the next couple of hours with between 500
and 1000 J/kg of CAPE and 25-30 kts of bulk shear across an area
that has between 0.70 and 0.80 inches of untapped PWAT. This will be
our area of focus over the next few hours, as overall activity wanes
(but does not completely dissolve) overnight. Expect a return of
scattered showers and isolated thunderstorms on Monday, with a focus
across Mohave, Clark, and San Bernardino counties. No changes made
to the forecast this evening.
.PREVIOUS DISCUSSION...449 PM PDT Sun May 4 2025/
.SHORT TERM...Today through Monday Night.
The strong storm system, currently centered just south of Lake
Havasu City, continues to bring convective activity to much of the
region. In areas where clearing is occurring, mainly Mohave County,
we are seeing storms form in an increasingly unstable environment,
with CAPE values in the 1000-1500 J/kg range through early evening.
Storms will diminish in coverage and intensity after sunset.
However, dynamic forcing will be enough to keep scattered shower
activity going through the night in many areas. Convective activity
increases again Monday around sunrise for Clark and Lincoln counties
as well as the Colorado River and Mohave County. Much cooler than
normal temperatures will be the norm for today and tomorrow as we
reside on the cool side of the trough. Temperatures will run 10-15
degrees below-normal through Monday.
.LONG TERM...Tuesday through Saturday.
A period of quieter weather begins Tuesday as the strong trough of
low pressure that brought us all of the active weather these past few
days moves off to the east. A few showers could linger on Tuesday in
Mohave County. Subsequently, a building ridge will slingshot our
temperatures from well below normal to well above normal by the end
of the week. Ensembles are in remarkable agreement on temperatures
in Las Vegas reaching the mid-upper 90s by Saturday with a 10%
chance of reaching 100. No significant winds or precipitation are
expected beyond Tuesday.
&&
.AVIATION...For Harry Reid...For the 00Z Forecast Package...The
threat of showers and thunderstorms has diminished in the short term
across the valley, with only a slight chance for the remainder of
the evening. The winds forecast has also been decreased for the
evening period, with speeds generally remaining less than 10 knots.
There is still a low chance of an outflow boundary from distant
storms moving into the valley through 06Z. Additional storms are
possible tomorrow, with the best chances between 18Z and 00Z. Away
from storms, winds are expected to remain below 10 knots. Skies will
be BKN to OVC through the TAF period with bases remaining 8kft to
10kft into tonight, falling to 5kft to 8kft tomorrow.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...The Las Vegas area TAF
will see conditions similar to those described for Harry Reid
through tomorrow. Elsewhere, showers and thunderstorms will remain
the primary concern Monday for all area terminals except KBIH and
KDAG. Winds at KBIH will be northerly with intermittent gustiness
through tomorrow. At KDAG, gusty winds will persist through tonight
before decreasing tomorrow. Showers and embedded thunderstorms will
redevelop in the Lower Colorado River Valley tomorrow afternoon
after 19Z. Most areas will see skies BKN to OVC through the TAF
period with bases remaining 8kft to 10kft into tonight, falling to
5kft to 8kft tomorrow.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Soulat
DISCUSSION...Berc
AVIATION...Planz
For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter