Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/05/25
previous forecast discussed below.
235 PM Update...
Current high pressure over the area, with some high clouds
moving in overhead from an approaching system. Conditions remain
dry through tonight, with high temperatures in the low to upper
50s across Central NY and NE PA.
High pressure erodes as a disturbance moving north and east
across the Great Lakes overnight tonight will bring widespread
rainfall across the area Saturday morning. Heavy, intense
rainfall is expected at times as a strengthening low level jet
originating from the western Gulf will draw plenty of moisture
northward and PWATs will be rising to around 1.20-1.40 inches
Saturday. Additionally, wind gusts around 30-35 mph are
expected Saturday morning through afternoon for the Finger Lakes
region and the hills area south of Syracuse.
As this first feature continues to move off to
the northeast, rain showers may become more scattered in nature
during the afternoon or toward Saturday evening before the next
plume of moisture arrives. There is some uncertainty with where
the axis of heaviest rainfall sets up on Saturday but there
looks to be a general 0.25"-0.75" of rain through Saturday
evening with localized amounts of around 1.00 inch possible.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
220 PM update...
Main concerns in the short term are focused on the lingering
rain showers and relatively cool conditions on Sunday, followed
by the potential for a quick hit of up to 2 inches of snow in
central NY Sun night and early Monday morning...and a few light
rain/snow showers into Mon afternoon.
Large area of low pressure over northern Quebec will rotate
eastward Sunday night into Monday as a trailing cold front
draped over the Northeast back into the TN Valley slowly drags
itself to the east. This boundary will be the dividing line
between the warm/moist air to the south and the cool/dry air to
the north. A ribbon of 2-3 standard deviation PWs will ride
north/newd along and south of this boundary and provide the
moisture needed for widespread rain showers. This boundary is
expected to sag slowly to the south on Sunday as the cooler air
inches closer from the north. As this occurs, the higher
probabilities for precip move south as well.
Temperatures are expected to only climb into the mid 40s in NY
and into the lower to mid 50s in ne PA on Sunday.
The challenge with this forecast arrives in the form of a weak
embedded short wave and the potential for accumulating snow late
Sunday evening into early Monday morning. This short wave is
being resolved on some of the model guidance (NAM and GFS) but
is not on the CMC and the ECMWF, so attempting to discern if it
will occur is presenting a bit of a challenge. If this wave does
form and track on the cool side of the front, then there is the
potential for 1-2 (possibly up to 3) inches of snow from
Steuben County over to the northern Catskills and southern
Adirondacks...with the higher amounts in the elevated terrain
locations. Conditions remain dry to the north if this wave
doesn`t occur and areas south of I-88 will see the rain change
over to snow and only light accums. The current forecast
incorporates some of this snow potential in the form of a narrow
band of about 1-2 inches and a half inch or less to the north
and south.
Temperatures in the 30s Monday morning will only rise into the
mid to upper 40s close to 50 by the afternoon. The next wave
starts to push in from the northwest Monday afternoon. A few
scattered rain showers (and rain/snow showers in the higher
terrain) will occur Mon afternoon but with limited impacts
expected.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
220 PM update...
A rather dramatic pattern shift will occur Monday night and
Tuesday as a sharp, cold Canadian short wave drops south and
southeast from the Great Lakes into the Northeast. Northwest
winds will increase Monday night and temperatures will fall
rapidly Mon night from the mid 40s and into the mid to upper
20s Tue morning. As this occurs, forcing along the front and on
the southern edge of the upper low will trigger widespread snow
showers. The introduction of some lake induced instability and
steepening lapse rates could allow for the generation of snow
squalls with gusty winds as well.
The pattern behind this wave appears to be setting up for some
lake effect snow showers into Tue and Tue night. However, even
with 850mb temperatures around -13 deg C and a steady flow from
the northwest, the high sun angle during the day Tuesday should
keep the snow from accumulating too much downwind/southeast of
Lake Ontario.
The 850mb ridge axis starts to push in from the west Tuesday
night, which will start to bring the LES to an end. Some
clearing may occur early Wed morning which could trigger rapid
raditional cooling and bring temperatures down into the upper
teens and lower 20s.
Quiet weather conditions the rest of the day Wed as high
pressure builds in before the pattern shifts to the southwest on
Thursday and temperatures begin a climb back to near normal.
Highs on Wed in the 40s will be replaced by temperatures in the
mid 50s on Thu.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected until at least 12z. Showers will
move in overnight but restrictions will be delayed a couple
hours after the showers start. Ceilings will be fairly quick to
fall into MVFR and Fuel Alt. Then IFR will be possible at most
terminals by midday, with SYR and RME just hanging onto Fuel
Alt restrictions. Visibilities will also be reduced with
guidance going as low as 2SM. That seems a bit low for only
light showers expected, but if a heavier shower were to develop
and pass over a terminal, then visibilities may end up lower
than forecasted for a brief moment.
Winds will become light and variable this evening. However,
early Saturday morning, winds begin to pick up and become gusty
with peak gusts as high as 25 mph in the afternoon hours. Winds
will start out easterly to southeasterly but become more
southerly by the end of the TAF period. Low-level wind shear
(LLWS) is expected at all terminals, though it will be
borderline at times. Still, southeasterly winds of 40 to 50 kts
are expected around 2000 ft AGL between 12 and 18z at most
sites. It will linger slightly longer at SYR and RME.
Outlook...
Saturday Night through Sunday...Periods of rain likely with
associated restrictions.
Monday 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...KL
NEAR TERM...KL/MWG
SHORT TERM...BJT
LONG TERM...BJT
AVIATION...BTL
Area Forecast Discussion
National Weather Service Grand Rapids MI
1040 PM EDT Fri Apr 4 2025
.KEY MESSAGES...
- Rain tonight into early Saturday
- Cold pattern next week; snow showers Monday
- Temps rebounding late next week but showers return
&&
.UPDATE...
Issued at 1040 PM EDT Fri Apr 4 2025
Lowered POPs for the next few hours based on radar trends. HRRR
and other CAMs show rain blossoming in an area of f-gen moving
across Lower Michigan overnight while the heavier convective
rains stay south of the forecast area,
&&
.DISCUSSION...
Issued at 337 PM EDT Fri Apr 4 2025
- Rain tonight into early Saturday
Frontal zone lifts back north through the Ohio Valley region
tonight but stays south of MI. Series of lows moving along the
front and upper jet entrance region lift brings widespread rain
back into the area with the possibility of one or more enhanced
FGEN bands. Spread still remains in QPF solutions for this reason
but the most likely scenario is for around one quarter to one half
inch of rain south and east of GRR. There are still a few
ensemble solutions suggesting an inch or more of QPF near I-94
which could lead to some nuisance flooding but since the front
and main thunder risk stays to our south the probability of those
higher amounts seems relatively low. Most of the rain pulls away
by Noon Saturday but a few showers may linger into mid afternoon
around JXN.
- Cold pattern next week; snow showers Monday
Big pattern change on the horizon as deep, moist southwest flow
is replaced by northerly flow from almost the North Pole. Recent
rainy pattern accordingly transitions to much below temperatures
and even some snow. Coldest air will be overhead on Monday and
Tuesday when deep longwave trough digs into the GrtLks Rgn and
minus 15C H8 air swoops down. The arrival of the "Arctic" front
on Monday triggers a band of robust snow showers which may even
be followed by a period of NNW flow lake effect Monday night. Some
accumulations of an inch or two are possible, with current
guidance favoring areas northeast of GR where the best synoptic
lift along the front is progged.
- Temps rebounding late next week but showers return
Aforementioned deep upper trough lifts out midweek and
temperatures moderate to closer to normal vales by the end of the
week. However additional/renewed troughing aloft is shown and that
brings the threat of rain showers back to the region.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 700 PM EDT Fri Apr 4 2025
Conditions will gradually transition from primarily VFR to MVFR
and eventually IFR and patchy LIFR by early Saturday morning due
to deteriorating cigs overnight with rain showers. The threat for
isolated thunderstorms at our southern terminals is too low to
warrant inclusion in any of those terminal forecasts tonight.
Conditions will gradually improve from LIFR to IFR then MVFR
through the day Saturday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
UPDATE...Ostuno
DISCUSSION...Meade
AVIATION...Laurens
Area Forecast Discussion
National Weather Service Louisville KY
1053 PM EDT Fri Apr 4 2025
.KEY MESSAGES...
* Ongoing historic and possibly catastrophic flooding event will
continue through the weekend. Heed any flood warnings issued as
this will be a life threatening flood event across much of
Kentucky and southern Indiana.
* A few strong/severe storms possible this afternoon across southern
Kentucky.
* Another round of strong/severe thunderstorms expected overnight
and into the day on Saturday. Severity of storms on Saturday is
highly dependent on storm evolution overnight.
* Drier conditions expected for early next week.
&&
.UPDATE...
Issued at 1052 PM EDT Fri Apr 4 2025
The 00z runs of both the 3km NAM and HRRR seem to have come to a
better agreement on when this line of potentially strong to severe
storms start to work into our area. Timing seems to be working into
our far northwest and western CWA sometime between 6-8z. The
northern section looks to potentially be more of a bowing, strong
wind concern where as potentially as you go further south and west
you start to have a slightly higher chance for a spin-up tornadoes.
The other question is how much do these storms diminish as they work
eastward into south central IN and central KY. While the Nam3km wants
to drop off the threat of severe fairly quickly, the HRRR keeps
strong storms into the pre-dawn hours.
Will need to monitor a bowing segment of severe storms coming out of
southern IL and into far western KY and the southeastern most tip of
Indiana. This features is currently riding along the sfc boundary
and could bring severe storms into our area by 6 to 8z. Made changes
to the forecast grids to update PoP timing.
Issued at 834 PM EDT Fri Apr 4 2025
With the loss of daytime heating, SBCAPE has dropped over central
and southern KY this evening. While there are a few isolated showers
and thunderstorms seen on radar, there is no threat of severe.
We have allowed some of the Areal Flood Warnings to expire while we
see a lull in the rain activity for a couple of hours here this
evening. We still remain in both an Enhanced risk for severe weather
mainly west of the I-65 corridor and a Slight risk to the east for
the possibility of a line of severe storms arriving late, after
midnight into the early morning hours of Saturday. Sfc boundary to
our south will start to lift northward and allowing for temperatures
to warm, especially for Louisville where temperatures have been in
the 50s for most of the day. The one thing we are going to watch is
just how much does the line of storms that develops to our west
diminish as it works towards southern IN/central KY.
Issued at 606 PM EDT Fri Apr 4 2025
Severe Thunderstorm Watch is in effect for most of central and south
central Kentucky until (10pm EDT/9pm CDT). Scattered Cu over the
southern half of KY into TN this afternoon allowed for temperatures
to warm into the 80s this afternoon and help to destabilize the
atmosphere. There is a tight, north to south oriented SBCAPE
gradient over central KY with values as high as 2000-2500 J/kg over
the KY/TN border and up into parts of the Bluegrass and Lake
Cumberland region. Main threat so far with any storms that have form
have been large hail, but also gusty damaging winds are also a
possibility. Generally, the tornado threat appears to be low.
As of 6pm EDT, local radars was showing a few cluster of isolated
strong storms stretching from from Larue southward into Barren and
Allen counties. The main threat with these cells has been sub-severe
hail and the thought is these storms will stay marginally severe but
with an eastward push into high SBCAPE values, a few isolated severe
warnings are still possible. Most of this activity should be
diurnally driven and the start to diminish with the setting sun.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 255 PM EDT Fri Apr 4 2025
Surface warm frontal boundary continues to lift northward across the
region this afternoon. The front is approaching the I-64 corridor
presently. To the south of the front, skies have clear out a bit
with partly to mostly sunny conditions noted. North of the front,
extensive low-level cloud cover remains. This results in an
impressive thermal gradient across the state. Temps up in the
Covington area are in the lower 50s with lower 80s along the KY/TN
border region.
For the remainder of the afternoon, main forecast concern will be
convective redevelopment across southern/central Kentucky. Satellite
imagery shows agitated Cu across the southern part of the state with
area radars showing some scattered showers popping up. The vast
majority of those showers are in the I-65 corridor between E-town
and Bowling Green coincident with a tongue of higher moisture.
Recent CAM runs suggest that continued convective development is
possible. HRRR runs remain rather aggressive here showing scattered
strong convection developing across southern Kentucky. The model
proximity soundings do show a kinematic and thermodynamic profile
supporting supercell structures. However, there are a few negative
factors showing up here. First, model soundings do show layer of
warmer air aloft above 700 mb. Secondly, a strong forcing/lifting
mechanism isn`t readily available here. Simply differential heating
may be the only driving force behind convection. The best forcing
still resides well to our west back toward the synoptic cold front
and stronger low-level jet axis across LA/AR/MS/MO. The 3K NAM was
much less aggressive with convective development this afternoon in
southern KY, mainly because it too had a much stronger warm layer
above 700 mb.
Overall, we plan on keeping scattered showers and thunderstorms in
the forecast for this afternoon and into early this evening. There
is a risk of severe weather with any storm that can obtain a strong
updraft and get going to take advantage of the environment. Should
that occur, large hail and an isolated tornado risk would be on the
table. The best chances of severe weather would generally favor
those areas south of the WK/BG Parkways and perhaps west of I-65.
For tonight and Saturday, we expect a line of storms to develop well
to our west along an approaching cold front. This activity should
spread eastward into our region late tonight and early Saturday
morning posing a risk of damaging winds and isolated spin up
tornadoes within the line. The majority of the CAMs do show this
line weakening with time, though most of the CAMs do push the line
through the region with an extensive trailing stratiform
precipitation shield remaining over area for the remainder of the
night.
The convective evolution of tonight`s convection will strongly drive
the threat of severe convection for Saturday. Many of the CAM`s
keep the stratiform precipitation shield going across much of
region, with some secondary convective redevelopment across our
southeast sections Saturday afternoon. On the other hand, CAMs like
the 3KNAM suggest that the overnight convective line with fizzle
prior to getting to the I-65 corridor. This essentially leaves much
of our area convectively untouched and more primed for stronger
convection Saturday afternoon. Overall, I would consider Saturday`s
severe potential to be conditional at best. The current slight risk
area from SPC is justified for now, given the spread. However, the
severe threat could be modulated up or down in later forecast as we
see how convection behaves overnight. Highs on Saturday will be
mild with upper 60s and lower 70s expected.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 407 PM EDT Fri Apr 4 2025
Surface cold front enters western Kentucky through the evening hours
on Saturday, into early Sunday morning. Primary H5 trough axis
remains situated over the southern Plains maintaining mid-level
southwesterly flow. Deterministic guidance continues to depict
several short-waves and vort maxima that traverse across the Ohio
and Tennessee River Valleys. This will be enough to maintain rain
shower activity in the vicinity of this cold front into Sunday
morning and any remnant MCS or QLCS in western Kentucky. Saturday
night into Sunday Morning, another 1.0 to 1.5 inches of rainfall is
expected across much of the area, as this is where 12z HREF mean QPF
values are set. Local probability matched-mean (LPMM) values
indicate pockets just above 2.0 inches are possible with stronger
storms if they are able to develop. This will continue to present
hydrologic issues already set in motion by the preceding rainfall
over the past 3+ days. As for any severe threat Saturday Night into
Sunday, it will be a question of how much instability is left ahead
of the cold front. Most of the CAMs show the warm-sector very worked
over, with 12z HREF mean MUCAPAE under 300 J/kg across much of the
region. Therefore, a few stronger isolated thunderstorms are
possible, but appears that any kind of severe threat stays in
western Kentucky where better lift and instability will be present
as this system tracks eastward. By Sunday morning, the boundary
layer remains very stable, but additional weak lift maintains general
rain showers. Sunday afternoon, primary H5 trough axis lifts toward
the western Ohio Valley pushing the surface cold front into far
eastern Kentucky. Weak post-frontal lift may continue to generate
light showers, and this gradually pushes eastward through the rest
of the afternoon. By the evening, primary H5 height falls are
finally in eastern Kentucky, and weak H5 height rises start which
will finally dry out conditions across the area.
Monday and Tuesday, weak H5 ridge builds into the western Ohio River
with primary subsidence occurring over the Great Lakes Region where
surface anticyclone develops. This will promote northerly flow and
CAA, pushing afternoon high temperatures into the 50s across most of
the area, and early morning lows into the lower 30s, and possible
upper 20s in some locations. Main H5 ridge axis starts to push
through the region on Wednesday which will send temperatures back up
in the upper 50s and lower 60s across most of Central Kentucky. Next
H5 trough moves begins to enter the Great Lakes and western Ohio
River Valley early Thursday Morning. Strongest H5 height falls start
Thursday mid-morning, providing lift to develop rain showers.
Ensemble guidance including GEFS favoring 50-60 percent
probabilities for rainfall at least 0.10 QPF especially east of
Interstate 65 on Thursday.
&&
.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 701 PM EDT Fri Apr 4 2025
A very busy forecast during this aviation time period as we will
start out with isolated showers and thunderstorms between 00-04Z
across central Kentucky and southern Indiana and as a result we
will have TEMPOs for all terminals during this time period as
the environment could develop thunderstorms at any time. Later
tonight a large squall line of storms will enter from the west
and prog eastward during the night. TEMPOs will be 4 hours for
this line of storms which are highlighted for each of the
terminals. These storms could contain brief gusty winds 20-30
kts and heavy rainfall which could reduce surface visibilities
to 1-3 SM. The strongest thunderstorms should wind down by 12Z
however we will continue to have a steady stream of moisture all
the way through 06Z Sunday and likely beyond. Expect TSRA and
SHRA for all terminals during this time. Cloud ceilings
initially will be IFR for SDF and HNB and fluctuating between
VFR and MVFR for RGA, LEX, and BWG. After 06Z we should have
widespread MVFR to IFR flight categories for all terminals
through 06Z Sunday. Categories will likely be IFR when we have
falling rain and closer to MVFR if we can get some pockets of
little to no rain. HNB, BWG, and SDF will have the higher
confidence of all day rain and LEX and RGA could see during the
day on Saturday of some breaks in the rain.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Flood Watch through Sunday morning for KYZ023>043-045>049-
053>057-061>067-070>078-081-082.
IN...Flood Watch through Sunday morning for INZ076>079-083-084-
089>092.
&&
$$
UPDATE...BTN
SHORT TERM...MJ
LONG TERM...00
AVIATION...00
Area Forecast Discussion
National Weather Service Morristown TN
842 PM EDT Fri Apr 4 2025
...New UPDATE...
.UPDATE...
Issued at 833 PM EDT Fri Apr 4 2025
No significant changes have been made for the forecast for
tonight. Isolated showers are possible in NE Tennessee and SW
Virginia for a couple more hours. Otherwise, tonight will be dry.
With at least some clouds expected and possibly increasing
overnight with continued WWA, lows tonight will be mild in the
60s in the Tennessee Valley.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 324 PM EDT Fri Apr 4 2025
Key Messages:
1. Anomalously warm conditions continue with potential record
breaking daily high minimum and daily high maximum temperatures.
2. A low potential for some showers and storms across the northern
Cumberland Plateau tomorrow, however, most will remain dry.
Discussion:
A deep upper trough atop the Desert Southwest and the Bermuda High
to our southeast continues to promote strong warm and moist air
advection. This is reinforced by temperatures approaching daily
record high maximum temperatures within the last hour or so. The
strong diurnal heating has also lead to widespread cu field
developing across the forecast area in which orographic forcing has
helped promote a few isolated showers across higher terrain of the
Cumberland Plateau and southwest Virginia. Latest SPC mesoanalysis
depicts MLCAPE between 1000-2000 J/kg, however, a lack of synoptic
forcing and a weak elevated inversion around 650mb has prevented
instability from being all that effective this afternoon. While the
occasional isolated shower and perhaps tstorm will exist across
higher terrain into the evening, the overall impacts will be
minimal. If a cell manages to tap into the instability some small
hail and localized gusty winds may occur.
Activity will wane with the end of diurnal heating. Expect a dry and
warm overnight where record high minimum temperatures may also be
broken. As southwesterly H85 flow amplifies to near 40kts overnight,
wind gusts in excess of 30mph will be possible across higher terrain
of the mountains. The anomalously warm conditions will continue into
Saturday as SPC sounding climatology suggests H5 heights will be
near the daily max per KBNA standards.
The aforementioned upper level troughing will be slowly shifting
eastwards with increasing divergence aloft. The front which has
retrograded north and west this afternoon will slowly nudge eastward
as well. CAMs are mostly trending dry but a few, namely the HRRR and
ARW, want to bring some scattered activity onto the northern
Cumberland Plateau well ahead of the front in the afternoon. In this
scenario isolated strong and gusty winds and small hail cannot be
ruled out given MLCAPE approaching 1000J/kg and effective bulk shear
near 50kts. Again, this is conditional on any showers or storms even
making it onto the plateau as confidence in that is low at this
time. Most locations will remain dry all of Saturday.
Daily Record High Maximum Temperatures
Date Chattanooga Knoxville Tri-Cities Oak Ridge
04-05 89(2023) 89(2023) 86(2023) 88(2023)
Daily Record High Minimum Temperatures
Date Chattanooga Knoxville Tri-Cities Oak Ridge
04-05 67(2023) 64(2023) 57(2023) 68(2023)
&&
.LONG TERM...
(Saturday night through next Friday)
Issued at 324 PM EDT Fri Apr 4 2025
Key Messages:
1. Widespread showers and thunderstorms affect the area Sunday,
especially in the morning, with potential for strong storms with
heavy rainfall.
2. Much colder temperatures Monday through Wednesday, with lows near
to below freezing across much of the area for Tuesday and Wednesday
mornings.
3. Another storm system for Thursday. There is a potential of severe
storms with the main concern being large hail and damaging winds.
Confidence is low on the development of this system since it is 6
days out.
Discussion:
For Saturday night and Sunday, the upper trough across the mid-
section of the nation finally lifts out as a long-wave upper trough
becomes established over the eastern half of the nation.
Strong jet dynamics will move across the Ohio and Tennessee valleys
enhancing the fronto-genetic forcing across the region by early
Sunday morning. Widespread showers and thunderstorms can be
expected. Overall, CAPE is only around 500 but plenty of effective
shear (50 knots) and 0-1km shear (25-30) knots. Most of the shear is
speed shear with mainly a southwest wind profile. Main severe storm
concern will be damaging winds.
Limiting factor for severe storms is timing of line of convection.
The latest HREF and deterministic GFS suggest a morning timing but
the NAM is more noon/afternoon. If storms are latter than a greater
potential of a tornado due to greater low-level instability.
Besides the severe storms, NAEFS shows abnormally high PWs and 850mb
moisture transport. Heavy rainfall is expected with this line of
storms with localized flooding possible.
For Sunday and Monday morning, the drier air advects into the region
with the upper trough passage during the day. Drier and much cooler
temperatures are anticipated.
For Tuesday night through Wednesday night, dry northwest flow and
much cooler airmass will move into the southern Appalachians.
Surface ridging building into the area will set the stage for
potential freeze/frost across much of the area.
For Thursday, a digging northern stream upper trough will move
across the Great Lakes into the Ohio and Tennessee valleys.
Impressive QG Forcing and cold air aloft with this trough axis.
Also, strong jet will pull north across the Ohio and Tennessee
valleys placing the area under the favored right entrance region.
This will enhance the fronto-genetic forcing with the associated
frontal boundary. Evolution of the instability with this system is
still uncertain but mid-level lapse rates will be above 7 degrees.
Steep lapse rates due to the cold air advection aloft and strong
dynamics could set the stage for vigorous convection development
in the afternoon/evening. Main concern will be damaging winds and
large hail. Confidence is low given this event is 6 days from now.
For Friday, drier and cooler air returns.
&&
.AVIATION...
(00Z TAFS)
Issued at 725 PM EDT Fri Apr 4 2025
VFR conditions will prevail with mostly scattered clouds through
tomorrow. Gusty southerly winds will subside shortly after sunset.
Tomorrow southerly winds will be gusty again starting in the late
morning hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 67 88 65 72 / 0 10 50 100
Knoxville McGhee Tyson Airport, TN 68 87 64 72 / 0 10 40 100
Oak Ridge, TN 67 86 62 70 / 10 10 60 100
Tri Cities Airport, TN 63 86 62 72 / 20 10 30 100
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...KRS
LONG TERM....DH
AVIATION...McD
Area Forecast Discussion
National Weather Service New York NY
1101 PM EDT Fri Apr 4 2025
.SYNOPSIS...
High pressure passes overhead tonight. A warm front approaches the
area on Saturday and may lift to the north Saturday night. A cold
front pushes through Sunday, followed by weak low pressure
tracking offshore on Monday into Monday night. A secondary cold
front pivots through late Monday night into early Tuesday. High
pressure builds for mid week before pushing offshore Thursday. A
frontal system may approach late on Friday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Made slight adjustments with POPs for rain late tonight into
early Saturday. Also increased some outlying area with their min
temperatures based on observed and forecast temperature trends.
Min temperatures only range from 41 to 48. A lot of low level
dry air so any echoes traversing the area before 2AM EDT are
expected to have rain not reach the ground. The boundary layer
expected to become more moist after 2AM EDT which when slight
chance to low chance POPs for rain appear in the western parts
of the forecast region.
Heights rise aloft slightly tonight as ridging builds into the area.
A very strong ~190kt anticyclonically curved upper level jet streak
will build well north of the area in southeastern Canada. At the
surface, the cold front that passed through this morning will stall
offshore. High pressure centered to our north will move through
and offshore tonight.
With a northwesterly flow, some drier air is filtering into the
area. Clouds continue to gradually thin and clear from north to
south. The clearing will not last too long as mid and upper level
clouds increase around midnight with a wave of low pressure
approaching from the south west. So even though winds will be light
tonight, the cloud cover will not allow for efficient radiational
cooling. The winds also turn easterly as the high shifts offshore,
which will start to bring in an increase in low level moisture.
Stuck with NBM for low temperatures which gave 40s everywhere.
With some lift ahead of the approaching wave and associated warm
front, some light rain will be possible, mainly for NYC north
and west after midnight.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The warm front continues its approach on Saturday and may lift
north of the area Saturday night. There is some uncertainty
across the latest guidance on whether it will lift completely
through or stall somewhere over the area. Regardless, with the
front at least nearby, wet conditions are expected. There is
also some disagreement across the CAMs on exact timing of rain.
The HRRR is the fastest, bringing widespread rain in after 8AM.
If this verifies, the current forecast may be a few hours too
slow. Much of the rain will be light to locally moderate.
However, Saturday night elevated instability increases and may
allow for some heavier showers and thunder. No severe weather is
expected. Have added in patchy fog Saturday night into early
Sunday morning with combination of light winds, moisture laden
boundary layer and some increase in dewpoints.
Highs will be cooler than the normals for early April on
Saturday. Highs may just break 50 across LI, NYC and northeast
NJ, but likely stay in the 40s up in the Lower Hudson Valley and
southern CT. Lows Saturday night will actually run a bit warmer
than normal, in the 40s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
The period begins with an amplified ridge in the west and a
developing eastern CONUS trough as the ridge in SW Atlantic migrates
east. A cold front slowly pushes in from the west and moves across
on Sunday. This will yield high end chance and lower end likely PoPs
for much of the CWA during the day Sunday. PoPs then increase
further Sunday night as some strung out PVA is progged just
downstream by NWP on a SW flow aloft. This should develop a wave or
waves of low pressure along the boundary late Sunday into Sunday
night / early Monday. Uncertainty remains slightly above average
with respect to how far to the south and east the cold front slows
down and possibly stalls late Sunday into early Monday. For now have
taken a middle of the road approach and followed consensus PoPs,
thus stuck very close to the NBM in this regard. Any low pressure
that develops gets east of the area later Monday into Monday night.
Thus, any likely PoPs move offshore Monday afternoon into Monday
evening. A secondary boundary, a cold / occluded type boundary
approaches into Tuesday morning. It won`t be until we get behind
this boundary that a large portion of the column dries out. Look for
strong cold air advection to follow with a W to NW flow as a cP air
mass out of Southern Canada builds. This will result in
temperatures not getting out of the 40s during the day Tuesday
with variable cloudiness with a cold pool aloft and likely
strat-cu cloud deck at times. 850 mb temps are progged to get
down to -10 to -12C with 1000- 500mb thickness in the lower 520s
by Wed AM. Wed AM wind chills are likely to get down into the
upper teens to lower 20s across a good portion of the area, with
actual air temperatures mainly around or below freezing. With
high pressure in control look for dry conditions for the mid
week. The high will begin to push offshore sometime on Thursday
with a return flow out of the south developing. Temperatures
begin to moderate on Thursday, with coastal areas remaining
rather chilly with a wind off the ocean during the afternoon
hours which will likely drop temperatures back into the 40s.
Towards Friday low pressure out of the Ohio Valley and its
attendant frontal system will start to draw closer. Any
precipitation though will likely hold off until either late in
the day or at night based on the latest NWP consensus.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
High pressure moves across and offshore tonight. A warm front
approaches from the south late tonight into Saturday. The front
slows down on its northward progress Saturday into Saturday
night.
VFR initially through much of tonight. Towards daybreak Saturday,
rain chances increase with MVFR becoming more probable. Rain in
this time period, late tonight into early Saturday morning,
will probably be more intermittent. Rain is expected to become more
steady Saturday by mid to late morning with MVFR becoming likely.
Conditions are expected to further deteriorate to IFR late afternoon
into evening Saturday as rain continues. LIFR will be possible
late afternoon into evening Saturday with potential furthering
lowering of stratus and some potential fog development.
Winds will be NW initially this evening and near 5-10 kts. Winds
further lower in speed late this evening and overnight while
becoming more NE. Winds become more easterly Saturday and
increase to near 10-15 kt. Gusts can be expected for all but
KSWF which will be near 20 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of MVFR and IFR could be 1-4 hours off from TAF.
Conditions could fluctuate between MVFR and IFR Saturday
afternoon.
Saturday evening, could have some fog development with LIFR
possible.
.OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
Saturday night: Potential fog especially across Long Island and
Southern CT. Otherwise, rain showers. A slight chance of
thunderstorms. IFR to locally LIFR. Easterly wind gusts 15- 20
kt along coast subsiding.
Sunday: Potential early fog across Long Island and Southeast CT.
Rain showers likely with MVFR to IFR possible.
Monday: Rain showers mainly early with MVFR possible. Otherwise
mainly VFR.
Tuesday: Possible early rain showers for most terminals, possible
early rain/snow showers for KSWF. MVFR to IFR possible early,
otherwise VFR. W-NW wind gusts near 20-25 kt.
Wednesday: VFR. NW wind gusts 15-20 kt during the day.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Sub SCA conditions expected tonight with high pressure passing
overhead. An easterly flow picks up on Saturday and conditions
may reach marginal SCA criteria on the ocean waters and portions
of some of the non-ocean marine zones. For now, no headline is
in effect. Winds lower again on Saturday night.
Mainly sub advisory conditions prevail on the coastal waters, with
perhaps the eastern ocean waters being an exception with seas around
5 ft at times Sunday through Monday night.
Behind a secondary cold front Tuesday look for small craft
conditions to develop on all the waters with a W to NW wind
increasing. A brief period of marginal gales is possible late in the
day Tuesday into the first half of Tuesday night. Sub advisory
conditions return by Wednesday.
&&
.HYDROLOGY...
There are no hydrologic concerns through next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JE/JT
NEAR TERM...JE/JM/JT
SHORT TERM...JT/JM
LONG TERM...JE
AVIATION...JM
MARINE...JE/JT
HYDROLOGY...JE/JT