Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/06/25
Area Forecast Discussion
National Weather Service Binghamton NY
948 PM EDT Sat Apr 5 2025
.SYNOPSIS...
Multiple waves of low pressure along a slow moving frontal
system will lead to periods of rain through the weekend.
Cooling trend expected Sunday and Monday with a chance for light
snow Sunday night into Monday morning. Cold conditions will
persist through midweek with a chance of snow showers again on
Tuesday.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Some small changes to pops and temperatures with the evening
updates. The HRRR does have a touch of a rain/snow mix toward
sunrise Monday from the Finger Lakes to the NY Thruway corridor.
No accumulation would occur but will continue to monitor model
trends.
220 PM Update...
Warm front is pushing northward across the region this afternoon
and and evening. Scattered showers will continue this
afternoon east of the I81 corridor. Cold front pushes into the
region later tonight and crosses the area through Sunday
morning, with a wave low pressure riding north along a slow-
moving frontal boundary. This will bring a return to widespread
moderate to heavy rain showers overnight. Also, some embedded
thunderstorms can`t be ruled out as well overnight, especially
across NE PA. Current RAP and NAM both show a few hundred Joules
of MUCAPE with 50-70 knots of shear as strong low level jet
punches into NE PA.
Brief high pressure builds in behind the cold front on Sunday,
but conditions will be much colder, with highs only in the upper
30s to low 40s. A weak wave of low pressure will develop develop
along the stalled front, that will be south of our region
tomorrow, and rides up the front Sunday night into Monday
morning. Thermal profiles show some potential for mostly snow
across the Twin Tiers and into Central NY and a wintry mix
possible down into the Poconos Region. At this time, still quite
a bit of uncertainty, but there is potential for a quick 1 to 2
inches of snow across the Twin Tiers and into the Catskills, and
there will be some potential for a light glaze of ice in the
higher elevations of the Poconos. This will all be highly
dependent on how far south that cold front makes it tomorrow.
Some guidance, like the Euro, have the front much further south,
which would limit precipitation into NY and bring some light
snow into portions of NE PA.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
245 PM Update...
Definitely more of a winter feel through mid week with snow and
temps below freezing expected.
A shortwave will continue to trek to the NE Monday morning, with
lingering snow showers remaining into mid morning, switching to
rain and exiting the area by mid-afternoon. There is agreement
in guidance that a strong cold front will push into the region
sometime Monday evening. With some potential breaks in the
clouds providing sunshine and warming the surface temps into the
mid to upper 40s in the afternoon and the cold air mass moving
in, low level lapse rates become fairly steep through 700 mb. As
the cold front moves through, strong forcing from the front and
associated low pressure center just north of Lake Ontario will
allow for snow squalls to potentially develop. Timing is still
uncertain, but there is a small chance (<30%) that the squalls
could impact the evening commute for western regions of the CWA.
Currently, the most likely timing is after 8pm for most of the
region. 850 mb temperatures quickly fall to -14C to -16C by
Tuesday morning with lake effect snow likely in the Finger Lakes
and CNY, extending into the Twin Tiers and possibly Catskills.
Snow may start off in some banding structures through the early
morning, but sunshine will impart instability which will bring
cellular showers by mid-morning. Showers should dissipate by the
evening as winds shift and temps warm as a ridge builds in from
the SW.
It will feel more like February than April Monday through
Tuesday night. Lows Monday night fall into the low to mid 20s,
with afternoon highs only topping out in the upper 20s to mid
30s for most. With the ridge building in Tuesday night, winds
will be lighter and skies clearer, allowing temps to fall into
the low to mid 20s for everyone.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
315 PM update...
The weather pattern should remain active through the end of the
week as several shortwaves look to impact our region.
High pressure remains overhead Wednesday, but the cold airmass
will linger, as highs only reach the upper 30s to mid 40s. The
next weather maker will be in the from of a longwave trough
pattern that will dig into the central US Wed night/Thursday AM.
Guidance is in pretty good agreement that a shortwave moves
into the Central US, developing a surface low in the Great
Lakes region on Thursday, moving over NY sometime between
Thursday and Friday morning. The big question is how does the
pattern evolve as a 2nd, stronger shortwave moves digs into the
eastern US behind this first shortwave. There is some agreement
that a coastal low could develop for the weekend, but the
positioning and track of the low is uncertain as it will depend
on if the shortwave is more amplified and digs into the SE with
rain Sunday, or more compact and quicker to form a closed low
over the Mid- Atlantic with rain on Saturday.
Temps currently look to be a little above average with highs in
the low to mid 50s and lows in the mid to upper 30s.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
After a lull in rain shower activity, the next round of
scattered showers will move through overnight. Isolated
thunderstorms will also be possible in northeastern PA but
confidence was too low to include thunderstorms at AVP. Ceilings
will go from MVFR/Fuel Alt to IFR/LIFR fairly quickly.
Visibilities will be reduced as well and could briefly drop
lower than forecasted if any heavier showers pass over a
terminal. By around 12z, ceilings begin to improve as the rain
moves out and all terminals are expected to be VFR by 16-18z
Sunday.
Winds will be somewhat variable tonight before settling out of
the north-northwest early Sunday morning. Some gusts of 15 to
20 kts will also be possible during the daytime hours on Sunday
at all terminals. While there was not much guidance showing
low-level wind shear (LLWS), it was kept in at AVP from the
previous update. LLWS is not expected to be a concern after
03-04z.
Outlook...
Sunday Night through Tuesday...Scattered rain and snow showers
may bring occasional restrictions.
Wednesday...Mainly VFR with high pressure overhead.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DK/MPK
NEAR TERM...DK/MPK/MWG
SHORT TERM...JTC
LONG TERM...JTC
AVIATION...BTL
Area Forecast Discussion
National Weather Service Columbia SC
921 PM EDT Sat Apr 5 2025
.SYNOPSIS...
Abnormally warm conditions continue this weekend. Temperatures
will continue to be near record values on Sunday. A weak cold
front will sink into the Carolinas/Georgia late Sunday. A
secondary more significant front will move slowly through the
forecast area early next week. Expect widespread showers and a
few thunderstorms late Sunday and Monday. Much cooler
temperatures expected behind the front next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Message(s):
- Unseasonably mild overnight lows continue.
Strong high pressure from the surface to aloft off the southeast
coast will continue to dominate the weather tonight. This
feature will begin to moved slowly eastward through Sunday.
Models indicate a low level jet will setup across the area as a
40 kt low level jet helps to keep the boundary layer mixed
overnight. Expect surface winds from 6 to 12 mph after midnight
through sunrise. As a result, the chances for fog are low but
there may be enough low level moisture for some low clouds. With
dewpoints in the lower/middle 60s and PW values around 1+
inches some sct/bkn low clouds could form. HRRR indicating best
chance for any low cloud formation would be along/east of I-95
corridor. Expect temperatures to only fall into the middle 60s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Key Message(s):
- Showers and thunderstorms likely late Sunday through Monday
- Periods of heavy rain and a few strong storms possible.
The surface and upper ridge near the area will begin to break down
and move southeast late this weekend. In response, the upper low out
west will be lifting northeast into the Plains. This will drive
a slow moving cold front toward the area into Monday. The
models appear to be slowing down the eastward progression of the
front. The bulk of any showers Sunday afternoon appear to be
focused to the west of the area, so lowered the pops especially
in the east. Expect breezy conditions especially in the
afternoon. A few gusts to near 30 mph possible. A Lake Wind
Advisory may be needed but appears marginal at this time. The
showers and a few thunderstorms will move moving across the area
late Sunday night through Monday. The instability appears weak
overnight but deep layer shear strong. Think the highest
probability of a few severe storms will be Monday morning as a
tongue of higher instability lifts northeast along the frontal
boundary aided by a 50kt low level jet- streak. the highest
threat in the east Midlands near I-95. Upper level divergence
will be maximized during this period. So went with categorical
pops. Locally heavy rain possible given deep south- westerly
flow along the front and precipitable water around 160% of
normal, so potential for training through the day as the front
moves ever so slowly toward the coastal Plain. Overall, average
qpf expected in the 1-2 inch range with isolated higher amounts.
Temperatures above normal Sunday with highs in the upper 80s to
near 90 in warm advection pattern ahead of front. Low
temperatures above normal Sunday night in the low to mid 60s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Key Message(s):
- Cooler weather likely for much of next week.
Little change to the long term forecast. After a cold front
exits east of the region, much drier weather is expected through
mid-week. Temperatures will be closer to normal with high
temperature generally in the 60s for Tue and Wed and 70s for Thu
and Fri. Lows through the long term will mainly be in the 40s
except on Wednesday morning when temps may drop into the mid
30s, although not optimal radiational cooling given ridge axis
to the northwest and a relatively tight pressure gradient,
noticed low-level jet around 20 kts. Global ensembles favor
troughing developing over the Midwest near the end of next week
with mean PWAT values rising to 0.75 to 1 inch. This pattern
typically supports at least a slight chance of rain at the end
of the long term.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected through the TAF period although
there is some potential for MVFR predawn stratus at OGB.
Satellite imagery showing diurnal cumulus clouds have dissipated
with only some passing higher cirrus clouds. Surface analysis
shows a very slowly moving cold front extending from central KY
southwestward into northern LA where there has been continued
convection in the vicinity of the boundary. Strong southerly
flow will continue overnight across the area with winds around
7 to 10 knots which should prevent any fog concerns. However,
some guidance is suggesting stratus may develop along the
Coastal Plain and into the far eastern Midlands possibly
impacting OGB, so will include a tempo group for MVFR stratus
09z-13z. As the frontal boundary approaches on Sunday the
pressure gradient will strengthen and expect gusty southerly
winds 12 to 17 knots with gusts to 25 knots after 15z with
increasing high clouds through the day.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
1057 PM EDT Sat Apr 5 2025
.SYNOPSIS...
* Several frontal boundaries moving SE across the Commonwealth
bring periods of rain and a chance of a few thunderstorms
across Southern PA overnight.
* Unsettled pattern continues into early next week, with periods
of rain showers, snow potentially mixing in across northern
Pennsylvania.
* High pressure expected to bring drier conditions on Wednesday
before showers return on Thursday and into the end of the
week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A triple point near KBFD at 01Z with a narrow wedge of warm air
south along RT 219 and west through the KBTP and KPIT areas.
Shallow cool air damming was noted across the eastern 2/3rds of
the state with lower cigs.
Positive llvl theta-E advection from the SW will overrun the
quasi-stnry frontal boundary located near the I-99 corridor an
into Scent PA. This will be where the most frequent and heaviest
SHRA and Sctd/elevated TSRA will be found. Latest SPC analysis
shows very little sfc-mixed layer instability along the Mason-
Dixon Line, so any storms that do survive over cool airmass with
sfc temps in the mid 50s and Tds in the low 50s will be brief
heavy rain and maybe some pea sized hail at worst.
Sfc cold front extending from near KBFD to KPIT will push
gradually SE across the CWA overnight with rain becoming focused
over the SE half of the CWA after 07Z Sunday. An additional
widespread 0.25 to 0.50 of an inch is likely overnight near and
to the South of a KAVP to KIPT and KFIG line, with lighter
amounts further NW where some wet snowflakes will likely mix in
with the post frontal showers toward daybreak.
Min temps will range from Near 32F across the Far NW to the
low-mid 50s across the Lower Susq Valley.
Previous Disc...
In terms of hydrologic concerns, the bulk of rainfall this
morning remained mostly beneficial. The area of main concern as
rainfall begins later this evening will be across portions of
Elk County, where 24-hour rainfall reports (see PNSCTP) were
maximized in/around Saint Marys. One-hour FFG values remain
lowest (0.75-1") across Elk, Cameron, and Potter counties with
localized minima (below 0.50") in slight urbanized areas where
multiple bands of rainfall occurred this morning. Localized
nuisance flooding will be possible across these areas tonight,
especially if locally heavy rainfall and/or training showers
and/or storms occur.
Southeasterly near sfc flow will provide some window for fog
potential across portions of the Lower Susquehanna Valley
overnight based on RAP model soundings that outline saturated
lower-levels. Fog potential also remains a good bet across
portions of the Laurel Highlands, with upslope winds and
saturation in the lower levels highlighting the potential for
locally dense fog across higher elevations of Somerset, Cambria,
Bedford, and Blair counties into the early morning hours of
Sunday. Fog formation could lead to hazardous travel, thus it
will be important for motorists planning to travel overnight to
monitor forecast trends and be prepared for drastically changing
conditions across central Pennsylvania`s roadways.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Unsettled pattern continues into the short-term period, with
periods of showers in the wake of the cold frontal passage
overnight. Chances of precipitation remain throughout the day
and evening hours on Sunday as a jet streak remains north of the
area. Chances shift further south across the area later in the
day; however, as drier air begins to work its way in from the
northwest. Dry conditions begin eeking there way into the
forecast area (NW to SE) by morning hours of Monday morning.
Temperatures in the wake of the cold frontal passage will trend
much milder than recent, with MaxTs ~5-15F below seasonal
averages for the beginning of April. These colder temperatures
will allow for some potential for wet snow flakes to begin
mixing in across the northern tier (most notably at higher
elevations) with minimal accumulations expected ahead of Monday
morning. There is some uncertainty with regards to snowfall
accumulation in the short-term; however, and the highest point
accumulations less than 0.5" cannot be ruled out Sunday night
through Sunday morning.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Drier air working into Central PA on Monday behind departing
low pressure will bring an end to any lingering rain or snow
showers, though skies will remain mostly cloudy. All guidance
shows a shortwave tracking north of Pennsylvania Monday night,
bringing a cold front through the area. Some snow showers will
be possible along the front, though with the best moisture and
forcing passing north of the New York border, the best chance of
any light snow will be over the northwest mountains.
Much colder air works in behind the cold front, with ensemble
mean 850 temps of -8 to -12 C supporting high temperatures on
Tuesday in the 30s and 40s. This should also be cold enough to
allow for at least a few lake effect and upslope snow showers
through early Tuesday afternoon before subsidence increases as
high pressure builds in. Snowfall amounts will generally be less
than an inch. Gusty winds during the day on Tuesday will make
it feel very chilly with apparent temperatures in the teens and
low 20s across the northern and western mountains.
High pressure will keep dry and cool conditions in place
through Wednesday, but temperatures will begin to moderate
towards the end of the week. With temperatures expected to be
below freezing Monday, Tuesday, and Wednesday nights for most of
the area, make sure to take any necessary precautions to protect
any sensitive vegetation that may be growing already. Most
guidance shows another system moving in for Thursday/Friday but
there is still a lot of uncertainty in the timing and precip
amounts.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Late evening update.
Isolated storms have formed near the warm front late this
evening. Added tempo to MDT and LNS for Thunder for several
hours. Showers mainly out of the northern part of PA.
More information below.
00Z TAFS sent.
Next area of showers moving into the western sections of
central PA. Warmer temperatures across the west, has resulted
in isolated storms south of the PA border, and now forming just
east of PIT.
Anyway, expect conditions to lower overnight, as the
area of showers becomes more widespread.
Expect conditions to improve during the second part of
Sunday, as the cold front sags southward, and very dry
air works into the area.
Earlier discussion below.
After 00Z Sun, higher confidence in more widespread rainfall
across the area, generally NW-to-SE with MVFR-to-IFR ceilings
the most likely. Recent RAP model guidance does outline some
elevated instability across SE PA (MDT/LNS) that could lead to
some TSRA mentions; however, confidence remains well too low
(~10-20%) to include mentions in the TAF between 00-05Z Sun.
LLWS will remain a concern in the near-term with 925mb LLJ
stationed across NW PA.
In/around 06Z, model guidance does begin to indicate SE`ly flow
across SE PA, which remains favorable for fog and low ceiling
formation across the Lower Susquehanna airfields (MDT/LNS,
lesser IPT). A combination of HREF probs < 1/4SM and RAP model
soundings do raise concerns for MDT/LNS to dip towards LIFR
after 07Z with higher confidence at LNS (~70%) compared to MDT
(~50-60%) in lower ceiling formation. These concerns will also
remain valid across the Laurel Highland airfields (BFD/JST);
however, lower confidence on timing further west.
After 15Z Sunday, gradual improvement is expected west-to-east
with high confidence. The main uncertainty with respect to
prevailing MVFR-to-VFR will be timing with model guidance
outlining slightly varying times. This TAF package has stuck
fairly close to GLAMP guidance, which remains the most plausible
scenario based on current observations/forecast trends.
Outlook...
Mon-Tue...Restrictions likely NW Mtns. Snow showers possible.
Wed...No sig wx/VFR conditions expected.
Thu...Rain enters W, overspreads E. Restrictions possible.
&&
.HYDROLOGY...
Rainfall this morning remained largely beneficial, with
portions of the western Pennsylvania receiving between
0.75-1.25" of rainfall. Lower 1-hr FFG values are present across
Elk, Cameron, and Potter counties where multiple rounds of
showers occurred Saturday morning, and these will be areas that
will be most susceptible to flooding later this evening into
Sunday morning as the heaviest showers (and potentially a
thunderstorm) move across central Pennsylvania.
Forecast rainfall through the rest of the weekend generally
ranges between 0.50-1.25", with locally higher amounts possible
across the Laurel Highlands and southern portions of the Lower
Susquehanna Valley. No river flooding is forecast at this time.
The Conewango Creek at Russell is forecast to approach action
stage/7ft level Monday morning. The West Branch Susquehanna at
Williamsport may get close to the 10ft action stage by Monday,
topping out just above 9ft.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/NPB
NEAR TERM...Lambert/NPB
SHORT TERM...Lambert/NPB
LONG TERM...Bauco
AVIATION...Martin/NPB
HYDROLOGY...NPB
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
943 PM EDT Sat Apr 5 2025
.KEY MESSAGES...
- Multiple rounds of showers with heavy rain and a few
thunderstorms will affect eastern Kentucky through Sunday.
- A much colder air mass arrives behind a cold frontal passage
Sunday and lingers until mid-week.
- Frost and/or freezing temperatures are forecast for most places
Monday night and Tuesday night.
&&
.UPDATE...
Issued at 935 PM EDT SAT APR 5 2025
Weakening convection and associated outflow boundary and gust
front continues to move east across eastern KY as instability
decreases as we move further past sunset. With this in mind,
Tornado Watch 126 has been cancelled within the JKL CWA. Showers
or stratiform rain will spread east with some embedded thunder
possible. The showers and stratiform rain should continue into the
night, but the heaviest rainfall rates should remain south and
southwest of eastern KY through the night.
&&
.SHORT TERM...(Late this afternoon through Sunday night)
Issued at 315 PM EDT SAT APR 5 2025
A south-southwest to north-northeast oriented differential
heating boundary is serving as a quasi-frontal boundary across the
center of the forecast area as of early this afternoon. Most of
the shower activity today has been along and north/west of this
boundary. CAMS indicate isolated to widely scattered shower and
thunderstorm activity continuing near and north/west of this
boundary, with a marginal threat for strong gusty winds and large
hail as well as a minimal tornado threat if any storm can become
anchored to the differential heating boundary/front.
Upstream convective activity ongoing this afternoon over the
Mid-South region will move rapidly east and northeastward through
the Tennessee River Valley and southern Kentucky this afternoon
and early evening, reaching eastern and southeastern Kentucky by
late evening or early in the overnight and bringing a renewed
chance for strong to severe storms and heavy rain. WPC with its
afternoon issuance has maintained the Excessive Rainfall Outlook
from this morning, with a Moderate Risk in western and
northwestern parts of the forecast area and a Slight Risk for much
of the rest of the forecast area. Additionally, the SPC has kept
much of the western half of the forecast area in a Slight Risk,
with damaging winds and large hail the primary threats, but an
isolated tornado or two cannot be ruled out. The more recent HRRR
runs depict the QLCS over the Mid-South region currently moving
rapidly east and impacting southern parts of the forecast area
later this evening into the overnight.
Widespread shower and thunderstorm activity is expected through
much of the day Sunday, but with the risks for severe weather and
excessive rainfall diminishing through the day as the slow-moving
cold front crosses the area.
A much cooler air mass moves into the region behind the cold front
Sunday, but clouds and some showers will hang on through much of
Sunday night as the upper trough will still remain just upstream
of the forecast area.
.LONG TERM...(Monday through Saturday)
Issued at 315 PM EDT SAT APR 5 2025
The upper low to the north finally crosses the area Monday and
pushes another cold front across the area late in the day or
Monday night, with cold rain showers or possibly snow showers in
the far eastern upslope areas possible where an increase in low-
level moisture should occur. Clouds gradually diminish late
Monday night into Tuesday morning from northwest to southeast.
Mid level height rises and sfc high pressure are expected to
dominate for Tuesday into Wednesday. The main concern as this
high builds and ushers in colder and drier air is the threat for
widespread frost and below freezing temperatures for both Monday
night to early Tuesday, and again Tuesday night to early on
Wednesday as the growing season begins across eastern KY. This
high slips east of the area to begin the second half of the week
with an upper level trough/upper low developing and extending from
the Great Lakes into the Southeast. This combined with multiple
disturbances and a sfc low tracking north of the area will bring
a return of unsettled weather from late Wednesday night or early
Thursday through Friday.
Overall, temperatures will be below normal for Monday to
Wednesday, with temperatures peaking about 15 to 20 degrees below
normal behind the secondary front for Tuesday. Highs are
generally expected to be near normal for Wednesday through the
end of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 935 PM EDT SAT APR 5 2025
An area of showers and stratiform rain will continue to spread
east across eastern KY late this evening and into the overnight,
with rounds of showers expected through the end of the period. The
leading edge activity will bring some reductions down into the
MVFR range, though prevail reductions down to MVFR or lower should
gradually spread into eastern KY from northwest to southeast
between 02Z and 10Z with IFR more likely near and north of the Mtn
Pkwy corridor before 12Z. A gradual trend to mainly IFR should
occur from northwest to southeast between 12Z and 21Z. Winds will
generally be more northerly through 06Z north of the Mtn Pkwy to
begin the period at 10KT or less and variable to the south as a
boundary begins to gradually sag south. Winds should gradually
become north to northeast through 12Z as far south as JKL and SJS
and to the remainder of the TAF sites through the end of the
period with speeds generally less than 10KT or less.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 8 AM EDT Sunday for KYZ044-050>052-058>060-068-
069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...CMC
LONG TERM...CMC/JP
AVIATION...JP
Area Forecast Discussion
National Weather Service Pittsburgh PA
809 PM EDT Sat Apr 5 2025
.SYNOPSIS...
Rounds of showers and thunderstorms will continue into Sunday
with the approach and passage of a slow-moving cold front. Heavy
rainfall totals remain possible, and a severe storm or two is
possible this afternoon and evening. Much colder air arrives
behind the front for early next week, with a bit of wintry
precipitation expected.
&&
.NEAR TERM /THROUGH SUNDAY/...
KEY MESSAGES:
- Flood Watch remains in effect for much of the region; heavy
rain threat continues into Sunday.
- Marginal risk of severe storms this afternoon/evening.
- Cold front arrives later tonight and slowly crosses through
Sunday, bringing much cooler air.
-------------------------------------------------------------------
Evening Update...
No major changes needed to the forecast this evening as it
generally remains on track. The severe threat has ended, with
focus shifting to rainfall tonight as the cold front pushes
through the area. Up to an additional inch to inch and a half is
possible, which may trigger minor flooding (especially in areas
that have already seen heavy rain the past few days) and/or
exacerbate ongoing flooding. See the previous discussion below
for more details.
Previous Discussion...
The lingering boundary has pushed north as a warm front, and
has largely cleared the CWA, save for perhaps the far
northeastern corner (DUJ still showing a SE wind). This has
placed most of the region in the warm sector, with only
scattered showers at present. Some breaks in the clouds have
developed as well, and along with dewpoints increasing to around
60, this has allowed for some modest surface-based CAPE of 500
J/kg or less to develop, highest south of I-70.
As a shortwave trough rotates across the northern Great Lakes, the
western portion of the wavy boundary approaches and enters the
region tonight as a cold front. With time ahead of the front, the
500 J/kg line may creep northwestward to near PIT by 21Z according
to RAP mesoanalysis. Combined with sufficient levels of effective
shear, the SPC marginal risk of severe thunderstorms during the late
afternoon/evening appears justified. Poor lapse rates and the lack
of dry air aloft may temper the hail threat, but damaging wind gusts
and perhaps a tornado cannot be ruled out.
We also will continue with a heavy rain threat overnight into early
Sunday. Increasing convergence along the boundary will ramp up low-
level frontogenesis along it. Precipitable water values approaching
1.5 inches will pool just ahead, above the top end of climatology.
Saturated lower levels and decent warm cloud depths also point to
efficient rainfall production. NBM Probabilities of an inch or
more of rainfall through 8 PM Sunday are 40-60% generally south
of US- 422. However, locally higher totals are certainly
possible in any convective banding that sets up - 2 inches or
more doesn`t seem to be out of the question. Thus, the Flood
Watch will continue, and in fact may have to be extended past 8
AM Sunday if the heavy rain threat lingers past then.
Rain coverage peaks overnight and then slowly fades from north to
south on Sunday as the cold front slowly settles through the region.
Cold advection commences overnight, dropping temperatures into the
30s generally north and west of Pittsburgh by 12Z Sunday.
Temperatures will not rise much on Sunday, reaching/remaining in the
40s in most cases. Temperature profiles suggests snow and/or
sleet may mix in with rain north of I-80 Sunday morning, and
perhaps as far south as Pittsburgh by evening. No snow
accumulation is foreseen.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
KEY MESSAGES:
- Widespread precipitation ends by Monday morning with the
departure of the front.
- Below-normal temperatures continue with late day/Monday night
rain and snow showers.
-------------------------------------------------------------------
A low pressure wave along the front, which will lie in or near
the ridges by 00Z Monday, may reinvigorate precipitation
coverage Sunday evening, mainly east of Pittsburgh. The front
finally gets a good kick east by later Sunday night/early Monday
morning as troughing deepens over the Ohio Valley, bringing
widespread precipitation to an end. The snow/sleet possibilities
expand to most of the region Sunday night into Monday morning.
Any accumulation will likely be limited to less than an inch,
generally north of US-422 and on the higher ridges, as the warm
and wet ground is a hindrance.
Precipitation coverage may briefly drop off for part of Monday,
however another cold front dropping southeast from the Great
Lakes may bring scattered showers to the region later Monday
afternoon and night. Precipitation would start as rain with
daytime temperatures mainly in the upper 40s/lower 50s, but a
mix with and change to snow is likely Monday night, with a minor
accumulation of less than an inch possible during the nighttime
hours. Widespread low temperatures in the 20s are forecast,
representing well-below normal values.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
KEY MESSAGES:
- Cold air mass peaks on Tuesday.
- Dry weather briefly returns midweek before additional
precipitation chances by late week.
-------------------------------------------------------------------
850mb temperatures reach their minimum values of -11C to -13C on
Tuesday as the 500mb trough axis reaches the Atlantic Seaboard. By
this point, most snow showers should be confined to areas north of
Pittsburgh, and these will end during the day as low-level ridging
arrives. High temperatures some 15 to 20 degrees below normal can
be expected. Dry weather continues through Wednesday as the surface
high crosses, with a brief bout of quasi-zonal mid-level flow
pointing to some temperature moderation back to around 10 degrees
below normal Wednesday.
By Thursday, it appears likely that the upper trough will be
reinforced by a potent shortwave dropping across the Upper Midwest.
Ensembles differ on the exact details, but rain chances do ramp up
for Thursday and Friday as an associated surface low and maturing
frontal system may cross the Upper Ohio Valley. How quickly the
500mb trough axis crosses the region is in question, as some model
solution close off an upper low in the base of the trough, slowing
system progression. That could keep some threat of precipitation in
the forecast into Saturday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
A cold front advances southeastward overnight, with heavier
rain (and associated lower cigs/vis) overspreading the area
behind it. Widespread IFR to LIFR conditions are expected until
improvement gradually occurs Sunday morning and afternoon behind
the frontal passage and as the rain moves out of the area.
Additional showers, potentially including a wintry mix of rain,
snow and ice pellets, is expected late Sunday into Sunday night.
The best chance for wintry precipitation will be north of
Pittsburgh.
Winds shift to northwesterly and then northerly behind the cold
front but remain generally light, around 5 to 10 knots.
Outlook...
While the heavy rain threat ends on Sunday, a large-scale
weather pattern shift brings cooler weather and periodic
rain/snow chances (and associated restrictions) to the local
area through mid-week.
&&
.HYDROLOGY...
Heavy rainfall potential continues through Sunday. An
additional 0.75 to 1.50 inches is expected through Sunday
evening, with heavier rain tapering off behind a cold front.
Localized higher amounts with thunderstorms can`t be ruled out-
totals above 2 inches could be seen in localized cases. The
Flood Watch currently continues through 8 AM Sunday, and may
need to be extended depending on where the heavy rainfall threat
is likely to linger.
Precipitable water is expected to remain elevated through
Sunday, with some periodic jet enhanced ascent. Even after the
heavy rain potential ends, river levels will likely remain
elevated for a few days. Several River Flood Warnings are
already in effect for expectations of minor flooding, and many
other river forecast points will reach action stage.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch through Sunday morning for PAZ013-014-020>022-029-
031-073>078.
OH...Flood Watch through Sunday morning for OHZ039>041-048>050-
057>059-068-069.
WV...Flood Watch through Sunday morning for WVZ001>004-012-021-509-
510.
&&
$$
SYNOPSIS...CL
NEAR TERM...Cermak/CL
SHORT TERM...CL
LONG TERM...CL
AVIATION...Cermak/Hefferan
HYDROLOGY...CL
Area Forecast Discussion
National Weather Service Raleigh NC
936 PM EDT Sat Apr 5 2025
.SYNOPSIS...
Bermuda high pressure will extend westward across the Southeastern
states through Sunday. A slow-moving cold front will move through
the region late Sunday night and Monday. Canadian high pressure will
bring significantly colder air into the region during the early to
middle part of next week.
&&
.NEAR TERM /TONIGHT/...
As of 935 PM Saturday...
A sub-tropical high will continue to weaken and drift ewd across the
swrn N. Atlantic tonight, downstream of an extensive band of
convection and convectively-enhanced mid-level vorticity stretching
from the nrn Middle Atlantic swwd through the lwr OH, TN, and lwr MS
Valleys. Satellite loops indicate the associated swly flow between
the two will result in fair skies, with periods of mainly thin
cirrus and cirrostratus over cntl NC. Like this past morning,
however, areas of stratus will be possible around and especially
after daybreak, especially over the Sandhills and srn and cntl
Coastal Plain where surface dewpoints this evening are in the mid
60s F, versus upr 50s over the Piedmont. It will otherwise be
continued unseasonably warm, with an occasionally gusty swly breeze
and with temperatures in the mid-upr 60s and about 25F above average.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 235 PM Saturday...
* Marginal Risk of both severe storms and excessive rainfall late
Sun into Mon, with better chance on the heavy rain threat
* Anomalously warm again and gusty Sun, turning much cooler by early
Tue
A rather dynamic system is set to impact the Carolinas late Sun
through early Tue. A shortwave trough over the Southern Plains is
forecast in the guidance to track ENE into the TN valley Mon and
eventually dissipate as a sheared axis by early Tue. A very warm,
moist, and strong southwesterly flow will be in place with ridging
off the coast and troughing to our west and northwest, setting up
the potential for several rounds of showers and some embedded storms
starting late afternoon Sun through late Mon night. At the surface,
a cold front over the southern Mid-Atlantic, lower OH valley to TN
valley Sun will slowly collapse south and east, moving through
central NC Mon night as a surface low tracks up along the SE US and
Carolinas. A continental Polar airmass arrives in late in the period
early Tue with a secondary cold front.
It will be another very warm and breezy day to end our weekend with
mid to upper 80s and a few locales reaching 90 along/east of US-1.
Southwest winds will gust at times to 30-35 mph. We may be just shy
of record highs. Lows Sun night will be in the upper 50s far north
to upper 60s in the far south. Temperatures will be closer to
average Mon as precipitation chances and clouds take over - highs
upper 60s NW to upper 70s SE.
As for precipitation chances, showers are likely to develop late Sun
afternoon/evening across the far west/northwest Piedmont and
gradually work south and east to areas along/east of US-1 Sun night
into Mon morning. The HRRR and partly the ARW HREF members bring
showers across the NW Piedmont as early as Sun morning with decaying
eastward moving convection in TN. If this develops, highs could be
lower in the Triad with a weak outflow boundary moving east. But the
bulk of any precipitation should hold off until later in the day
where instability will be greater.
The highest precipitation chances area-wide will be late overnight
Sun night through Mon night. With precipitable water values above
the daily max between 1.5-1.8 inches, dynamic forcing with central
NC in the right-entrance region of an upper jet, as well as
instability, periods of heavy rain will be possible Mon aftn/eve.
The LREF total QPF through the event ranges from 1.3 to 1.8 inches,
with high end totals of 2.25 to 2.5 inches within embedded
convection. Will have to see what tomorrow`s HREF QPF shows, but the
marginal risk of flash flooding is warranted.
The severe threat is across our far NW Sun and far SE Mon.
Confidence on severe potential is somewhat limited due to expected
clouds, precipitation, and weak low-level lapse rates, but the shear
is certainly favorable for isolated damaging winds in the outlook
regions.
Precipitation should come to an end at or before midnight Mon night
as the system pulls out. Lows will be much cooler compared to the
many several warm nights, with upper 30s NW to upper 40s SE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 230 PM Saturday...
* Frost/freeze conditions likely on Tuesday night.
* Unsettled weather returns Thursday through Saturday with another
cold frontal passage, however exact details remain unclear.
After the cold front moves through the region on Tuesday morning,
cool, high pressure will build in. Highs on Tuesday should only
reach the mid to upper 50s, with some low 60s in the south. This is
10 to 15 degrees below normal. A reinforcing cold front will reach
the area very late Tuesday night dropping low temperatures further.
Temperatures are expected to dip into the upper 20s to mid 30s, as
seen by both the mean and 50th percentile of the European ensemble.
This will result in frost/freeze potential for all of central NC.
Wednesday and Thursday the region should still be under the
influence of the surface high, leaving the region dry and
temperatures slowly moderating, with highs reaching the upper 60s by
Thursday afternoon.
The next chance of rain returns Thursday night through Saturday as
an upper level trough and associated cold front approach the region
from the West. Models differ in the depth of the trough and timing,
creating high uncertainty in the forecast over this time period. The
GFS is showing a deeper and slower trough, with a cutoff low forming
south of the region on Saturday, bringing rain from Thursday night
through Saturday. The ECMWF shows a shallower trough with a cutoff
low forming to our north and rain over the region from Friday
morning to Saturday morning. Thus, there is at least a slight chance
of rain somewhere in the CWA from late Thursday night through the
rest of the extended period. According to the 50th percentile of the
GEFS and ECMWF ensembles, the best chance of rain comes Friday
afternoon through evening. High temperatures should be in the mid
60s to mid 70s each day, with lows in the mid 40s to low 50s
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 744 PM Saturday...
Lingering VFR stratocu continue to dissipate early this evening.
Expect few to scattered high clouds the next several hours, before a
thicker blanket of upstream high clouds fill in across central NC.
VFR conditions should largely prevail tonight, however some guidance
does indicate the potential for stratus along the coastal areas.
Can`t entirely rule out some of this stratus migrating near KFAY.
Overall though, confidence is much too low to include any mention of
sub-VFR ceilings at KFAY in this TAF package.
Expect periods of swly sfc gusts (15 to 20 kts) to continue
overnight before ramping up around 14Z with gusts peaking around 30
to 35 kts Sunday afternoon. A strong LLJ is still expected to
develop tonight, promoting periods of LLWS at KINT/KGSO and perhaps
at KRDU at times from ~06 to 13Z.
Steadier rain should largely hold off until after the 24hr TAF
period, however some recent guidance does trickle a few showers near
KINT/KGSO Sunday afternoon. Have added the mention of light rain at
these sites to account for this.
Outlook: A slow-moving cold front moving into the area from the west
will bring widespread rain and associated sub-VFR restrictions to
all of central NC Sunday night through Monday. Dry VFR conditions
will return Monday night into Tuesday. The next chance for sub-VFR
restrictions will arrive late Thursday into Friday with the arrival
of the next shortwave trough and frontal system into the Eastern US.
&&
.CLIMATE...
Record High Temperatures:
April 5:
KGSO: 87/1942
KRDU: 90/1942
KFAY: 91/1942
April 6:
KGSO: 89/2010
KRDU: 93/1967
KFAY: 91/2010
Record High Minimum Temperatures:
April 5:
KGSO: 60/2023
KRDU: 64/1910
KFAY: 64/2008
April 6:
KGSO: 65/2023
KRDU: 69/2023
KFAY: 69/2023
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...CBL
NEAR TERM...MWS
SHORT TERM...Kren
LONG TERM...Helock
AVIATION...Luchetti/CBL
CLIMATE...RAH
Area Forecast Discussion
National Weather Service Tallahassee FL
902 PM EDT Sat Apr 5 2025
...New UPDATE, MARINE...
.UPDATE...
Issued at 855 PM EDT Sat Apr 5 2025
The main changes to tonight`s forecast were tweaking overnight
lows, adding very low-end PoP for light showers to the western
portions of the area, and introducing patchy fog mainly along the
Flint River Valley. Otherwise, expect warm/muggy conditions with
mostly cloudy skies, and breeziness continuing near the coast.
&&
.NEAR TERM...
(Through Sunday)
Issued at 218 PM EDT Sat Apr 5 2025
Windy conditions are continuing this afternoon as the gradient
remains tight between high pressure to the east and the quasi-
stationary front parked along the Mississippi River. The front will
finally pushed eastward on Sunday as the upper trough kicks east.
However, the overall positive tilt of the trough axis will slow down
the progression.
By early Sunday afternoon across the Florida Panhandle and SE
Alabama, ahead of the front, the atmosphere will be modestly
unstable (MLCAPE of 800-1000j/kg) and modestly sheared (0-1km shear
~25kt and 0-6km shear ~30-35kt). However, convergence ahead of the
front will be limited, leading to uncertainty as to how much deep
convection can be maintained. Any storms that do form during the
afternoon will have the potential to be strong to severe, with
damaging winds, and perhaps a tornado or two, being the primary
threats. Additional storms will likely be supported right on the
frontal boundary as it makes it`s way into the forecast area by late
afternoon and early evening. SPC has maintained the Day 2 Slight
Risk for severe storms for the western CWA.
&&
.SHORT TERM...
(Sunday night through Monday night)
Issued at 218 PM EDT Sat Apr 5 2025
A cold front looks to continue moving across the region on overnight
Sunday into Monday. The mid-level perturbation that ejected out
ahead of the trough currently over the desert southwest, and the
primary forcing mechanism for showers and storms Sunday afternoon
and evening, quickly races off to the northeast. This will allow the
front to slow its forward motion until the trough over the desert SW
merges with a second trough over the northern Plains/Midwest. This
will lead to a moisture plume overhead, as southwest flow prevails,
with PWATs in the 1.75 - 2 inch range overnight Sunday into Monday
morning. Instability overnight will decrease slightly leading to
SBCAPE and MLCAPE between 500-1000 J/kg, which would be sufficient
for thunderstorms development. A LLJ around 35-45 knots with 0-1km
SRH greater than 150 m2/s2 points to favorable conditions for
organized thunderstorms along the line. The primary threat from
these thunderstorms would be strong gusty winds, but there is a low
end threat to possibly a couple tornadoes.
As the line slows down, persistent southerly flow at the surface
with southwest flow aloft and a slowing line could lead to training
storms. There`s uncertainty on how much the line slows down, but
this could result in a potential flash flooding threat, primarily
across the FL Panhandle, SE Alabama and extreme SW Georgia where the
moisture plume aloft is expected to drag along before being pushed
eastward by trough on Monday.
Expect overnight temps on Monday morning to be in the 60s with
daytime highs generally in the upper 60s to mid 70s.
&&
.LONG TERM...
(Tuesday through Friday)
Issued at 218 PM EDT Sat Apr 5 2025
Post-frontal, fairly benign conditions prevail into the extended
period. Northwest flow in the upper-levels, ridging in the mid-
levels and surface dew points in the 40s and 50s will lead to a
pleasant second half of the week. Expect mostly clear skies with
some scattered fair weather cumulus. A cold front looks to approach
the region this weekend, but without much moisture return, this
frontal feature looks to remain mostly dry. We could see breezy
conditions as the front moves across the region on Friday.
Daytime highs generally in the upper 60s to mid 70s on Monday
gradually warm up after the cold front moves on into the upper 70s
and low 80s by Friday. Overnight lows generally drop into the 40s
behind the cold front on Tuesday and Wednesday mornings. A rebound
with overnight lows in the mid 50s is expected by Friday morning.
&&
.AVIATION...
(00Z TAFS)
Issued at 606 PM EDT Sat Apr 5 2025
Gusty southerly winds abate around 00z with attention turning to
lower cigs. MVFR cigs continue at ECP and spread to much of the
terminals between roughly roughly 05z-09z. Based on the latest
guidance, confidence has increased in IFR from roughly 09z-14z
at much of the terminals, although it should be brief at ABY/DHN.
Brief restrictions in fog as well mainly in the ABY-TLH corridor.
The exception to the aforementioned restrictions will be at VLD,
with a brief period of MVFR around sunrise, with otherwise VFR.
Cigs will lift rapidly to VFR by 17-18z with the exception of
ECP where MVFR cigs prevail much of the day. Southerly winds
increase by late morning around 15-20 kts with gusts 25-30 kts.
&&
.MARINE...
Issued at 855 PM EDT Sat Apr 5 2025
A Small Craft Advisory is in effect for waters west of
Apalachicola until Sunday evening. Small craft operators should
exercise caution in Apalachee Bay late tonight. A blend of the
latest HRRR and NBM90 was used for winds to account for the latest
trends. The West Tampa Buoy (42036) was reporting a sustained SSE
wind near 15 kts, 4-ft seas, and a dominant period of 8 seconds
this evening.
CWF Synopsis:The tight pressure gradient between high pressure
over the Atlantic and a cold front over the central part of the
country will continue to yield fresh to occasionally strong south
to southeast breezes through Monday morning. Seas will continue to
remain elevated around 4 to 7 feet as well. Showers and
thunderstorms will become likely Sunday night and Monday as a cold
front passes through the waters. Behind the cold front, winds
turn more northerly Monday night then slacken Tuesday night into
Wednesday. Advisory conditions are expected to begin tonight ahead
of the front and persist until the front passes by NE Gulf on
Monday.
&&
.FIRE WEATHER...
Issued at 218 PM EDT Sat Apr 5 2025
Strong southerly flow will continue on Sunday ahead of an
approaching cold front, keeping mixing heights and dispersions
values elevated, especially across SW Georgia and the Florida Big
Bend. However, RH values will remain well above critical levels.
Rain will move in from the west late in the day and spread across
the region Sunday night into Monday. This will keep fire wx
concerns low. A much drier airmass will push into the region in
the wake of the front for Tuesday.
&&
.HYDROLOGY...
Issued at 218 PM EDT Sat Apr 5 2025
Locally heavy rainfall is possible with the cold front Sunday night
into Monday. This would be especially true if the front slows down
somewhere over our area, providing a focus for perhaps some brief
training of storms. The current forecast calls for rainfall totals
averaging around 1 to 2 inches, with the higher end totals over
southeast Alabama adjacent FL Panhandle and southwest Georgia.
The reasonable worst case rainfall (10% chance of exceedance) is
around 2.5 inches. While this rainfall wouldn`t cause any more than
nuisance flooding, there is still a Slight Risk of excessive
rainfall (level 2 of 4) for the 15% chance of exceeding flash flood
guidance over the Wiregrass. Flash flood guidance is this area is
around 2.5-3 inches in 1 hour, or more than 4 inches in 6 hours. A
flood risk would increase if the front slows down in our area,
causing an axis of heavier rainfall amounts to materialize.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 68 83 68 76 / 10 10 40 100
Panama City 70 80 65 72 / 10 30 80 100
Dothan 67 84 61 67 / 10 40 90 90
Albany 67 86 64 71 / 0 20 70 100
Valdosta 67 87 69 79 / 10 0 20 100
Cross City 64 85 67 82 / 10 0 0 80
Apalachicola 70 77 68 75 / 10 10 50 100
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Sunday evening for FLZ108-112-114-
115.
GA...None.
AL...None.
GM...High Rip Current Risk through Sunday evening for GMZ735.
Small Craft Advisory until 7 PM CDT Sunday for GMZ751-752-770-
772.
&&
$$
UPDATE...IG3
NEAR TERM...Camp
SHORT TERM...Oliver
LONG TERM....Oliver
AVIATION...LF
MARINE...Oliver/IG3
FIRE WEATHER...Camp
HYDROLOGY...Oliver