Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/16/22
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1028 PM EDT Tue Mar 15 2022
A cold front will move southward overnight with the
light rain and mountain snow ending and some patchy fog developing.
Mainly dry and mild conditions are expected late tonight through
Wednesday night. A storm system tracking towards the mid Atlantic
coast on Thursday may brush parts of our area with some rain
showers. Temperatures will remain above normal through the rest of
the work week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
UPDATE as of 1028 PM EDT...A weak disturbance moving along a
cold front is moving across southern New England bringing spotty
light rain and snow across the forecast area as a cold front
moves southward. The boundary is still north of the mid Hudson
Valley, southeast Catskills and NW CT and the I-84 corridor.
Some light wet snow has fallen across the southern Adirondacks,
where temps have fallen to 32F in the NYS Mesonet. Spotty light
rain has fallen across southern VT and the I-90 corridor south
and east with a few hundredths to a tenth of an inch. Based on
the observations and 3-km HRRR and NAM, the pcpn should diminish
between midnight and 2 am from west to east. Any snow
accumulations will be a coating to less than an inch in the
mountains. Cold advection will occur in the wake of the front
causing temps to fall into the 30s to lower/mid 40s.
Patchy fog may develop mainly in valleys or sheltered locations
with residual low level moisture in place and little wind
overnight in these areas. Expect low stratus clouds to persist
in the early morning hours, especially over the higher terrain.
Lows tonight will range from the upper 20s to lower 30s in the
mountains to mid and upper 30s in the valleys.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
On Wednesday, a surface anticyclone will become established off
the New England coast with a mild southerly flow developing
across our area. Heights will be rising aloft, resulting in mild
temperatures and no precipitation. Low stratus clouds and/or
fog in the morning should dissipate by afternoon, with mostly
sunny skies expected. Temperatures should warm into the 50s for
most of the area, with highs averaging around 10 degrees above
normal for mid March.
Continued dry and mild weather in store for Wednesday night,
with a persistent/light southerly flow across the region with
high pressure centered well east of New England. There could be
some low stratus clouds and/or patchy fog developing, especially
across the southern half of the area closer to the marine
Thursday should be mainly dry for at least the northwest half
of the area. We will have to monitor a cyclone tracking
northeastward from the eastern Carolinas off the mid Atlantic
coast during the day. Most sources of model guidance keep this
cyclone far enough away for only glancing effects in our area. A
few rain showers cannot be ruled out along the northwest
periphery of this system, so will mention of chance PoPs from
around the Saratoga and Capital Region south and east. Any
shower activity looks to be light and mainly scattered. This
system should at least spread a canopy of cloud cover that will
affect most of the region. The clouds should keep temperatures
down somewhat, but it will still be mild by mid-March
standards(highs mainly in the 50s).
As the cyclone continues to track northeast (south of Cape Cod)
Thursday night, a few showers may linger into the evening for
areas mainly from Albany south/east. Otherwise, dry conditions
are expected for the rest of the night as a ridge of high
pressure builds in from the west. Mild temperatures will
persist, with lows mainly in the upper 30s to lower 40s.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A complex low pressure system will bring some wet and unsettled
weather into eastern NY and western New England late Fri night
and for the upcoming weekend. Drier weather will return next
week with a high amplitude ridge building in over the Northeast.
Fri-Fri Night...A mid and upper level ridge weakens over the
Northeast on Friday, and the mid/upper flow becomes
southwesterly aloft ahead of a low pressure system moving into
the Midwest early Fri night. In the warm advection, ahead of the
low expect temps to rise above normal in the lower to mid 60s
with some upper 60s in the mid Hudson Valley, and 50s over the
higher terrain. Mid and high clouds will be increasing but the
daytime period should be dry. The cyclone moves toward the lower
Great Lakes Region with the warm front bringing some showers
from southwest to northeast across the forecast area. Some wet
bulb cooling may change the pcpn over to some wet snow over the
southern Adirondacks. Any accumulation is expected to be light.
Periods of rain will be widespread towards daybreak. Lows will
be in the mid 30s to lower 40s north of the Mohawk Valley and
Capital Region with mainly lower to mid/upper 40s south and
Sat-Sat Night...The parent cyclone moves slowly over the
central and northern Great Lakes Region based on the 12Z
GFS/ECMWF/Ensembles. A secondary low may form near southern and
eastern New England. It is possible a dry slot moves in during
the afternoon. Overall, strong moisture advection ahead of an
occluded boundary will continue periods of rain at least into
the afternoon. PoPs were kept in the likely and categorical
range. In the damp conditions, max temps will only be in the 40s
to lower 50s over the mtns, and lower to mid 50s in the
valleys. The occluded front will move across the region, and the
mid and upper level trough will linger. A mixture of rain and
snow showers is possible with the better chance of snow showers
over the southern Adirondacks, the southern Greens and possibly
into the western Mohawk Valley, and the northern Catskills. Some
light wet snow accumulations of a coating to an inch or two are
possible. Lows will be in the upper 20s to mid 30s over the
mtns, and mid 30s to lower 40s in the valley.
Sun-Sun Night...The medium range guidance and ensembles
continue to show cyclonic flow persisting aloft with the mid and
upper level trough lingering over the upstate and New England.
The cyclonic vorticty advection tied to the diurnal heating will
trigger isolated to scattered showers north of the mid Hudson
Valley and NW CT with some snow showers mixing in over the
southern Adirondacks. Highs will be in the mid 40s to lower 50s
in the valleys, and mid 30s to mid 40s over the hills and
mountains. The upper level trough gradually moves down stream
Sunday night. Some lingering snow showers and flurries will
continue over the southern Dacks and southern Greens. Colder air
infiltrates the region with lows in the mid 20s to lower 30s
over the higher terrain and lower to mid 30s in the valleys.
Monday-Tuesday...A trend to drier weather is expected on Monday
with the trough axis down stream and mid and upper level
ridging building in. Temps look seasonable for late March with
40s and 50s for highs. Some radiational cooling is possible
Monday night with the sfc high building in with mostly clear
skies and light winds, as lows will be in the 20s to mid 30s.
Mid and upper level heights increase with ridging over the East
Coast for Tuesday. Max temps will run above normal with 40s to
lower 50s over the higher terrain and lower to mid/upper 50s in
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A cold front will continue settling southward this evening, as
a weak wave of low pressure tracks along the front. Weak high
pressure will then build across the TAF sites during Wednesday.
Light rain will gradually overspread the TAF sites this evening,
and should last through around 06Z/Wed. The rain should be
light, so expect mainly VFR conditions initially, however a
period of MVFR Cigs/Vsbys will be possible between roughly
03Z-06Z/Wed as the lower levels of the atmosphere moisten. There
could be a bit of wet snow mixing in briefly at KGFL.
After the precipitation ends, lingering low level moisture will
allow for patchy fog and low stratus to be in place after
06Z/Mon. It`s unclear exactly how low visibility or ceilings
will be, but for now, will go with IFR Vsbys and MVFR
Cigs around 1-2 kft. There could be periods of LIFR/VLIFR
conditions between 08Z-12Z/Wed, but it`s unclear at this time
and may depend on just how much rainfall occurs.
Low clouds and possible fog may linger as late as 13Z-15Z/Wed,
before clearing develops and VFR conditions return. VFR
conditions are then expected for Wednesday afternoon, with just
some occasional high clouds, and a few cumulus clouds between
4000-6000 FT AGL.
Winds will become north to northeast at 4-8 KT this evening
(although will initially be from the southwest at KPOU until
around 01Z/Wed), becoming light/variable after midnight through
Wednesday morning. Winds will then become south to southwest at
4-8 KT by Wednesday afternoon.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Chance of SHRA.
Thursday Night: Low Operational Impact. Slight Chance of SHRA.
Friday: No Operational Impact. NO SIG WX.
Friday Night: High Operational Impact. Likely SHRA...RA.
Saturday: High Operational Impact. Definite SHRA...RA.
Saturday Night: Moderate Operational Impact. Chance of SHRA.
Sunday: Low Operational Impact. Breezy. Slight Chance of SHRA.
An upper level disturbance along a southward moving front will
continue to bring rain and mountain snow showers into this
evening. Mainly dry and mild conditions are expected late
tonight through Wednesday night. A storm system tracking towards
the mid Atlantic coast on Thursday may brush parts of our area
with some rain showers. Temperatures will remain above normal
through the rest of the work week.
Relative humidity values in increase to around 100 percent
tonight, dropping to minimum values of between 45 and 55 percent
on Wednesday. RH will increase to around 85 to 100 percent
Winds tonight will become northwest around 5 mph, shifting to
the southwest around 5 mph on Wednesday. Winds on Wednesday
night will be southerly around 5 to 10 mph.
No hydrologic issues are anticipated through at least the
Temperatures will continue to moderate this week, with well
above normal readings expected by Thursday into Friday.
Precipitation associated with a front moving southward across
the area through tonight will only bring light QPF to the area.
Otherwise mainly dry weather will occur through Friday, with
just some scattered light showers on Thursday. The warmer
temperatures will result in snowmelt across the higher terrain
where there is still 1 to 5 inches of liquid equivalent in the
snowpack. The snowmelt should follow diurnal trends, as
nighttime temperatures will drop into mainly the 20s/30s in
higher terrain areas. River rises are expected, but should not
be enough to cause flooding. MMEFS forecasts indicate no river
points exceeding minor flood stage through the next 7 days.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
Area Forecast Discussion
National Weather Service Boston/Norton MA
1013 PM EDT Tue Mar 15 2022
Round of brief showers this evening, especially along and north
of the Mass Pike. Drier weather expected Wednesday. Above
normal temperatures continue on Thursday with some showers
likely sometime later in the day into the evening. Even warmer
on Friday and with plenty of sunshine many locations away from
the immediate coast/localized sea breeze potential will probably
see high temps of 70+. Cooler temps arrive this weekend along
with some rain for Saturday. Mainly dry weather with more
seasonable temperatures are expected early next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
No major changes to the forecast this evening. Latest runs of
the HRRR ensemble and National Blend or models appeared to have
a good handle on the timing of the showers across southern New
England. Made some tweaks to rainfall chances and timing
overnight. Still expecting the majority of showers to be
offshore early Wednesday morning.
A fast moving shortwave crosses the region this evening. The
bulk of the forcing/dynamics will be across the northern half of
our region. Therefore, most of the showers will impact northern
MA but a few brief showers may find their way further south.
Even in northern MA though this activity will be short-lived
and exit the region near or shortly after midnight. Low temps
overnight will be in the 30s to near 40. We may have to watch
for a bit of patchy fog toward daybreak, where there is some
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
High pressure once again builds in on Wednesday bringing
subsidence, clearing skies, and dry weather. Additionally,
anomalously warm temperatures continue to surge north, and with
mixing to near 900 mb on Wednesday we`ll once again see highs in
the upper 50s and some low 60s. Initially more west/downslope
winds may help the CT River valley overperform compared to
elsewhere. The ridge of high pressure lingers overnight keeping
things dry, though clouds will be on the increase. Lows will
once again be in the upper 30s.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
* A period of wet weather likely late Thu into Thu evening with
relatively mild temperatures persisting
* Dry & unseasonably mild on Fri with highs of 70+ likely in many
locations away from the immediate coast/localized sea breezes
* Cooler afternoon temperatures this weekend with rain on Saturday
* More seasonable temps early next week with mainly dry weather
Thursday and Friday...
The Ensembles continue to be in very good agreement in the overall
pattern. Deep closed low in the vicinity of Alaska will team up with
the lack of upper level blocking in the North Atlantic. This
translates to a +EPO/+NAO, which supports zonal flow and will keep
the cold air locked up well to our north. The result will be
unseasonably mild temps Thu and well above normal temperatures on
High temperatures on Thu will be in the middle 50s to the lower 60s,
despite the likelihood of some showers especially across eastern
MA/RI later in the day and into the evening. The mildest of those
readings may end up in our northern zones; given the greater risk of
steadier rain will be near and especially southeast of the I-95
corridor. There still remains considerable disagreement with the
track of a shortwave and associated surface low on Thu. The NAM/RGEM
have a track closer to the coast and indicate a steady rainfall late
Thu into Thu evening. Meanwhile...the global models indicate a track
further southeast with just a brief period of light showers. Still a
significant spread amongst the GEFS/EPS members on the track.
Appears that the model guidance may be struggling as a result of
limited baroclinicity considering the time of year. Still need a bit
more time to sort this out, but it does appear that at least some
light showers are in store for much of the region later Thu into Thu
Friday will be the mildest day of the week with well above normal
temperatures. Guidance has 850T of +6C along with westerly flow and
expected sunshine. MOS guidance is likely too cool given a well
mixed atmosphere in pre-greenup, at least away from portions of the
immediate coastal/localized sea breeze potential. Therefore, many
locations should see high temps of 70+ away from parts of the
Low pressure will be approaching the region from the southwest late
Friday night into Saturday. Pretty good agreement in the guidance
that we will see rain on Saturday. Given high pressure in the
Canadian Maritimes, easterly flow may keep highs in the 40s to lower
50s and on the chillier side of those readings if the low cuts
underneath us. There probably will be some improvement by Sunday,
but lingering upper trough and shortwave energy may keep a lot of
clouds and even a few lingering showers across our region. High
temps probably in the 40s to middle 50s depending on how things
transpire, but leaning towards the cooler readings.
Early Next Week...
Appears lingering upper trough and high pressure slowly building in
from Quebec will result in more seasonable temperatures by early
next week along with mainly dry weather.
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
VFR conditions deteriorate to MVFR-IFR late this evening into
the overnight hours, mainly across northern and eastern sections
of the region. A brief round of showers this evening is also
expected, mainly across northern MA, but a few will find their
way south. Patches of fog are also possible late. Light NW
Wednesday...High confidence. MVFR-IFR conditions in northern and
eastern sections of the region will gradually improve to mainly
VFR by late morning/early afternoon. Light S winds with sea
breezes along the coast.
Wednesday night...High confidence. VFR. Light southerly winds.
KBOS TAF...High Confidence in TAF.
KBDL TAF...High Confidence in TAF.
Outlook /Thursday through Sunday/...
Thursday: Mainly MVFR, with areas VFR possible. Breezy. Chance
Thursday Night: MVFR/IFR conditions possible. Breezy. Chance
Friday: VFR. Breezy.
Friday Night: Mainly MVFR, with local IFR possible. RA likely.
Saturday: Mainly MVFR, with areas IFR possible. Windy with
local gusts up to 30 kt. RA.
Saturday Night: Mainly MVFR, with local IFR possible. Breezy.
Sunday: Mainly VFR, with areas MVFR possible. Breezy.
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
A weak low pressure and front will cross the waters tonight,
followed by high pressure Wednesday. Relatively light winds and
seas expected most of this time through Wednesday night.
Outlook /Thursday through Sunday/...
Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Rain likely.
Friday: Winds less than 25 kt. Seas up to 5 ft.
Friday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of
Saturday: Moderate risk for Small Craft Advisory winds with
local gusts up to 30 kt. Areas of rough seas. Chance of rain.
Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Rough seas up to 8 ft. Chance of rain.
Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 8 ft.
Area Forecast Discussion
National Weather Service Charleston SC
1041 PM EDT Tue Mar 15 2022
An area of low pressure will track through the region through
Wednesday night. Another cold front will slip through the
region later Friday into Saturday, with high pressure returning
early next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
The back edge of the rains associated with a mid level impulse
and the greatest surface mixing ratios will pull offshore by
12-1 AM, leaving us with NVA for a few hours. Guidance provides
mixed signals on the evolution of the next batch of convection
associated with the approach of a closed low aloft, it`s
counterpart at the surface, both of which shift east along the
northern Gulf Coast region, and a warm front to the south.
However, with increasing isentropic ascent and better forcing
from these aforementioned features, we anticipate a climb in
convective coverage after about 3 am. Activity looks to be
highest near and west of I-95, which aligns with the HRRR and
NAMNest which have performed the best the past several hours.
The places look to have the best overlap of upper difluence
with a 80-90 kt 250 mb jet, upward omega and a 30-40 kt jet at
925 mb. There is some negative Showalter values arriving over
parts of Georgia before daybreak, so we did show mention of a
slight chance of t-storms. No major changes to temps.
An impressive southern stream closed low across the lower
Mississippi Valley will trek east through the night, resulting
in a slow downward trend to heights aloft. An associated surface
low initially near New Orleans will head toward the Florida
Panhandle and into southern Alabama overnight, while a warm
front extends east-southeast, linking up with a developing low
off the northeast Florida coast. That secondary low occurs in
response to a short wave embedded within the southwest flow
aloft. Moisture will continue to deepen out of the Gulf and the
Atlantic, as PWat reaches near 1.5 inches. That along with
difluence aloft and isentropic ascent increasing on various
surfaces will lead to showery weather across the area. Models
differ regarding where the highest chances will be found, but
based on recent trends we do have our greatest coverage in
Georgia early on, with PoP as much as 70-90% in some locations.
We suspect additional revisions through the night. There does
remain the potential for some elevated t-storms late across
Georgia, with Showalter Indices below zero. And that has been
maintained from the previous forecast. It`ll be a mild night
with temps far above climo given extensive thick cloud cover and
an east and southeast synoptic flow. In fact many places might
not even be able to drop below 60F.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
High Impact Weather Potential...watching for stronger storm
possibilities on Wednesday.
Pattern Synopsis/Forecast: A fairly progressive flow pattern remains
in place across the CONUS today with a pronounced upper low moving
into the western Gulf Coast region. This system will bring our next
stretch of active weather to the region for midweek. Another Pacific
short-wave trough is advancing into the west coast and will undergo
some amplification across the central CONUS toward the end of the
week, before advancing up through the Great Lakes this weekend.
Larger scale flow will then become a bit more amplified across the
CONUS late in the weekend into next week as one more Pacific short-
wave trough works it`s way into the CONUS.
Details: Closed upper low will advance into the Gulf Coast states by
Wednesday morning before lifting up through northern Georgia and the
western Carolinas Wednesday afternoon and Wednesday night. At the
surface, low pressure is expected to develop along the central Gulf
Coast overnight into Wednesday, then slip up through the eastern
Carolinas through Wednesday night. Associated surface warm front
will be sliding northward through the area overnight through
Wednesday which will place at least a portion of the forecast into
the warm sector.
Still some mixed signals in guidance regarding the overall precip
evolution late tonight into Wednesday with the advancing warm front,
with some guidance suggesting a bit of a split...as one area of
precip moves up through the central/western Carolinas and second
piece along the main moisture channel getting shunted off to our S/E
(sort of seeing that pattern trying to emerge on regional radar
plot). Regardless, as we get later into the morning and particularly
the afternoon, increasing QG-forcing for ascent and upper level
height falls with the upper low will be spreading into the region
and likely to bring one or more additional rounds of showers and
thunderstorms, persisting into the evening. Categorical pops remain
justified through the day Wednesday, although the exact timing of
the more widespread precip remains problematic (as usual) and will
likely need adjustments.
Thunderstorm potential: Plume of elevated MUCAPE will be advecting
up into the region overnight and into the day Wednesday, and there
may be some ongoing, elevated thunderstorms in the region to start
the morning. But as we get later in morning and afternoon, heating
will likely generate some surface based MLCAPE, dependent upon the
track of the low and attending boundary and, of course cloud cover
and how much heating we can attain. Right now, the better
instability is likely to be across the GA counties where around 1K
J/Kg of MLCAPE is possible per HREF/GFS solutions.
Meanwhile, axis of stronger southwesterly unidirectional low-mid
level flow along the eastern side of the low will be spreading into
the region, resulting in 40 to 50 knots of 0-6Km bulk shear for the
afternoon. This continues to suggest at least some potential for
stronger storms and possibilities of a few severe storms if all
aligns. The entire forecast area remains outlined in a marginal risk
for severe storms in SPC`s Day2 outlook, which is reasonable at this
Later in the week: Low amplitude short-wave ridging, weak-ish
surface high pressure and drier air build through the SE states for
Thursday and going into Friday. There may be some fog around
Thursday morning, although we do not have that explicitly mentioned
in the forecast as of yet. But a return of FAIR weather is
anticipated for Thursday and into the day Friday, before some low
end shower potential creeps back into the forecast later in the day
Friday (see below).
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Pacific short-wave trough will dip into the central/southern plains
by early Friday before lifting into the Great Lakes heading into the
weekend. This will gin-up another storm system in the southern
Plains that also tracks into the Great Lakes, driving a boundary
through the SE states later Friday through Saturday. Primary forcing
with this system will slide by to our north. But enough low level
convergence with the boundary...upper level support and moisture
transport ahead of the front to maintain our higher end chance pops,
Friday afternoon into Saturday. Dry weather returns Sunday and the
first half of next week.
Warmest day this week is looking to be Friday, ahead of the
approaching cold front. Daytime temps dip back off for the weekend,
but still around of just above seasonable norms. Warming again next
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR a good chunk of the night. But then for later tonight and
early Wednesday we anticipate ceilings lowering as dew points
climb in advance of a warm front, and low pressure treks along
the northern Gulf coast and a secondary low forms off the
northeast Florida coast. MVFR seems most likely, but IFR can`t
be ruled out, especially at KSAV. Showers will become more
steady Wednesday as the surface low and associated warm front
draw closer, in tandem with forcing from a closed low
approaching from the west. Low end MVFR ceilings are forecast,
with a chance for IFR, at least at times through the day. At
least some surface based instability settles into the local
area, tempered though by the low cloud cover. Because of this we
chose not to go anything more than VCTS at KCHS, KJZI and KSAV
Wednesday, but refinements could be required as the event gets
closer, and tempo groups could be required for TSRA. This seems
most likely at KSAV from about 12-20Z at KSAV and a few hours
later at KCHS and KJZI.
Extended Aviation Outlook: High confidence for MVFR ceilings
impacting the terminal sites Wednesday night/early Thursday, along
with a risk for periodic IFR flight restrictions during that time.
Conditions trend back to VFR on Thursday and remain in place into
Friday, although late night/morning fog is possible early Friday
morning. Additional flight restrictions anticipated again Friday
night into Saturday with another cold front that will pass
through the region.
There has been a tightening of the gradient between the
Atlantic high and the upstream low across southern Mississippi
and southern Alabama. As a result we have bumped winds up a bit
from the previous forecast. Because of these higher speeds we
began the Small Craft Advisory on the AMZ374 waters a little
quicker than before; now starting it at 5 AM as some 6 footers
arrive by that time.
There does remain a chance for the Small Craft Advisory in
Charleston Harbor from about 15-21Z Wednesday. But it still
looks too marginal that I`d prefer to let the next shift take
another look when more guidance becomes available.
Tonight: High pressure centered north of Bermuda will give way
to a warm front from the south, while a very subtle inverted
trough persists over the shelf waters. This trough isn`t as
pronounced as many of these types are, so it is not expected to
keep winds NE over the shelf waters, instead it`ll just be
Easterly through the night. Speeds of 10 or 15 kt early on will
increase to 15 or 20 kt by daybreak Wednesday. With the
favorable onshore fetch, seas will reach 3-5 ft, highest on the
outer Georgia waters.
We did consider raising a Small Craft Advisory for Charleston
Harbor for Wednesday, but since it is so marginal, we choose to
hold off at this time.
Extended Marine Outlook: Low pressure system will impact the region
Wednesday and Wednesday night. Low end Small Craft Advisory
conditions are expected in the Charleston nearshore waters
Wednesday/Wednesday evening, and in the Savannah outer waters on
Wednesday. There will be a low risk of SCA conditions late in the
week into Saturday depending on the strength of another cold front
that will be moving through the region.
Rip Currents: Strong onshore winds, swell waves, and
astronomical influences will yield a Moderate Risk of rip
currents at Lowcountry/Coastal Empire beaches on Wednesday.
MARINE...Small Craft Advisory from 5 AM to 7 PM EDT Wednesday for
Small Craft Advisory from 7 AM Wednesday to 1 AM EDT Thursday
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
955 PM EDT Tue Mar 15 2022
A moist low pressure system crosses the Gulf states tonight
and Wednesday reaching the South Carolina coast Wednesday evening.
Widespread rain will cross the area then taper off and end Wednesday
night. Dry weather returns Thursday with a weak, yet moist, cold
front crossing the region late Friday into Saturday. High pressure
will provide dry weather from Sunday into the first part of the
.NEAR TERM /THROUGH WEDNESDAY/...
As of 945 PM EDT Tuesday: Forecast still on track. A few
modifications were made to the PoPs in an attempt to capture the
slow and steady encroachment of drizzle along the southwest tier
of the CWA.
A bowling ball of a closed, stacked low pressure system will
rotate through the deep south, pushing into GA late in the day
Wednesday. Moisture influx ahead of the system and favorable upper
level diffluence will support continued lowering and thickening of
clouds this evening followed by slow but steady increase in rain
chances later this evening into Wednesday. Peak of rainfall coverage
and rates will be Wednesday with a stout 30 to 40 mph low level jet,
divergence aloft and steepening upper level lapse rates thanks to
the approaching of the cold upper low possibly supporting rainfall
rates in excess of a half inch per hour. Fortunately the system
and associated heavier cells should generally maintain forward
momentum, limiting rainfall amounts and the threat for excessive
rainfall. As it stands, much of the area from the escarpment
and points east has a good shot at an inch plus of rainfall with
localized amounts of two plus inches. While a hybrid wedge will
likely limit surface based instability with the system Wednesday,
elevated instability rising up and over the wedge front across the
southern tier and impressive mid level lapse rates may support
a few stronger thunderstorms south of I-85 with large hail and
damaging wind the primary threats. Rainfall tonight will help to
lock in the expected hybrid wedge which when combined with the
widespread rain and cloud will make for a dreary Wednesday with
daytime highs topping off in the 50s to near 60.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 100 PM Tue: Upper low will continue to wobble northeast across
the CWA Wednesday night. Most of the CWA will remain under a shallow
sfc high and in-situ CAD, but temps should remain mild enough to
maintain an all-liquid forecast. Elevated convection appears
possible above the wedge inversion; TMB looks likely to be near our
southeastern border and any SBCAPE thus should be kept south of the
CWA. That said, NAMNest depicts small pockets thereof within our
border counties overnight. Regarding tornado threat, shear
parameters are not all that exciting although perhaps too strong for
comfort; hodographs are chaotic except in the lowest kilometer, and
it is hard to find a prog sounding where a parcel could be lifted
from below 1 km. Decent lapse rates above the inversion however will
combine with modest effective shear to pose some hail risk into
early Thursday. HRRR and HiRes-FV3 generate some short updraft
helicity swaths, seemingly from elevated parcels. SPC Day 2 brings
Marginal Risk into our far south with 5% hail prob; based on these
findings those probs could end up being brought a little further
north into the area if anything.
Flash flood threat early Thursday appears limited but nonzero. The
plume of moisture preceding the upper low may have exited the CWA
prior to the start of the period, but storm motion and Corfidi
vectors will shrink as the low moves overhead. As noted above
effective hodographs do not reveal much organization, but at least a
small possibility exists for training convection.
Most guidance agrees the upper low will be in an unfavorable position
to produce precip or convection in our CWA by mid-morning Thursday,
and CAM output backs that up. The ECMWF is a bit slower than the
consensus in carrying it out of the area, but overall we allow PoP to
diminish during the morning. Sfc/upper ridge should fill in from the
west in the wake of the low, keeping us dry and with above-normal
temps through Friday morning.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 145 PM Tue: A mature low pressure system will move thru the
mid-Mississippi Valley on Friday, while the warm conveyor belt of
that system crosses the southern Appalachian region. Deep saturation
should occur over the CWA, along with a wave of strong midlevel WAA,
and accordingly PoPs return. Given modest upper level lapse rates,
the setup may support another round of elevated convection Friday
into Friday night. A narrow warm sector may reach the CWA Friday
night between the WCB and cold front; a plume of small SBCAPE is
seen on the global deterministic models, concurrent with large deep
layer shear. Warm midlevels appear to be a limiting factor for the
viability of any sfc based parcels, but for now this appears to be a
period of interest. Cold front should clear out PoPs and sky cover
for Saturday. Winds do turn northwest along the southern
Appalachians, but GFS and Canadian GDPS depict too little low-level
moisture for continuing PoPs. ECMWF is the only available model
depicting NW flow precip later Saturday, but it continues to show it
into early Sunday. Temps should fall back to about climo Saturday
night, but still warm enough that if precip were falling at that
time in the NW flow areas, it would be more likely rain than snow.
Dry weather should last the remainder of the fcst period, with temps
above normal beneath a sfc high of southern Rockies origin.
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: All sites are presently VFR as a cirrus
shield encroaches on the region out of the southwest. Most areas
are CLR or only carrying FEW/SCT cirrus decks, but as these thicken
in the next few hours, a gradual transition to BKN/OVC is expected.
A midlevel (still VFR) cloud deck is expected to push in thereafter.
Deterioration should come as a slow burn, with sites generally
expected to transition to MVFR ceilings from west to east between
08Z and 12Z, except for KCLT, which may see a marked delay in the
arrival of lower clouds. Winds should remain light and variable
the next few hours, before gradually becoming more reliably NEly
between 03Z and 06Z. For now, have worked VCSH in starting near or
shortly before daybreak; CAMs are generally not handling the onset
of rainfall well as aforementioned NE winds result in a hybrid CAD
wedge developing overnight. After daybreak, most guidance depicts
MVFR visibility developing rather quickly with onset of -SHRA,
while lowered (IFR) ceilings only slowly spread eastward across
the Piedmont. The Upstate sites as well as KCLT continue to carry
PROB30s for -TSRA Wednesday evening - but it remains difficult to
pin down an exact timing for convection.
Outlook: Brief drying and a return to VFR conditions is expected
Thursday and Thursday night. Another moist frontal system and
associated restrictions arrives later on Friday.
Area Forecast Discussion
National Weather Service Shreveport LA
934 PM CDT Tue Mar 15 2022
Still seeing some returns on radar this evening across portions of
northern and northeast Louisiana, so will maintain the low end
PoPs for this area as we move into the overnight hours before they
end completely overnight. The inherited forecast appears to be on
track, so not many changes needed other than to account for
current trends, which was not far off from the forecast. Look for
patchy fog to develop overnight with lows in the lower to mid 40s
across the region. /33/
.PREV DISCUSSION... /issued 630 PM CDT Tue Mar 15 2022/
For the 16/00z TAFs...Still seeing a wide variety of flight
conditions late this afternoon across the region, however, VFR
conditions are starting to become more dominant. KMLU continues to
report IFR conditions with low cigs and -RA, KELD continues to
report MVFR conditions with lower cigs, while the remainder of our
sites are now reporting VFR conditions. The upper-level low
continues to move towards the east this afternoon, and radar
returns have been trending in the downward direction. Should see
some fog develop overnight across much of the region, which will
bring some LIFR flight conditions overnight and towards Wednesday
morning before scattering out by late Wednesday morning. /33/
PREV DISCUSSION... /issued 218 PM CDT Tue Mar 15 2022/
SHORT TERM.../Tonight through Wednesday Night/
Watervapor, Visible Satellite Imagery and radar mosaic continues
to show our upper level trough spinning across the heart of the
Four State Region and since the noon hour, we have seen an
increase in light rain coverage across portions of NE TX into NW
LA and SC AR. Given the location of the upper trough and the slow
eastward progression expected overnight, have held onto high
chance pops beginning at 00z across our eastern third with slight
chance pops as far west as the Piney Woods of NE TX with pops
ending across our far eastern zones by 06z. Cloud cover has been
pesky today, in and out across our far western and southern
fringes but feel like this cloud cover will hang in through much
of the evening elsewhere, albeit thinning across our northwest
half after midnight. It`s this thinning that is concerning because
that will likely lead to fog development late tonight. HRRR and
latest 3KM NAM output is pretty insistent that dense fog will
develop across our west and northwest half overnight. For the
forecast, have mentioned patchy fog everywhere tonight after
midnight and introduced patchy dense fog across our western half
which is just shy of what we would need for a dense fog advisory.
Will let the next shift take a crack at this possibility if they
think one is necessary. Assuming this forecast holds, we will keep
the dense fog in through much of the morning across at least our
western zones with improving conditions during the afternoon.
Other than these short term concerns over the next 24 hours, the
remainder of the forecast is pretty much a temperature one with
high on Wednesday warming in the lower to middle 70s assuming we
break the cloud cover on Wednesday with overnight lows Wednesday
Night falling into the middle 40s to lower 50s.
LONG TERM.../Thursday through Tuesday Night/
As we move into the end of the work week, the SPC has a marginal
risk for much of our area on their day 3 valid through Friday
morning. Our next cold front will be arriving with another vigorous
mid level trough during the overnight hours. Overall, this system is
looking fairly strong like the one last night, but just with limited
moisture return. So our QPF on the WPC day 3 is only anywhere from a
tenth to half inch. So this will help to keep us drying out so much
before the next arrival early next week. This will be good for
continued progress on the drought of late. The GFS and ECMWF are
very similar with an open wave centered over Oklahoma by sunset on
Thursday. The upper trough does sit back and tilt slightly negative
a tiny bit before ejecting out east of the MS River valley by early
on Friday. Most of the QPF is baked into the nighttime hours with
signal lighting up right around 00Z and ending by 12Z.
A large area of surface high pressure at 1025mb will sprawl in under
the departing upper low and make for notably cooler readings for
Friday afternoon and on into the weekend especially on the low end
with more seasonal upper 30s and lower 40s. Highs will be a little
closer to normal on Saturday and even back above for Sunday. The
southerly flow returns early next week as the surface high moves
east, with our morning lows jumping back through the 50s and into
the 60s toward the end of this long term. Our highs early next week
are looking to be well above normal and loaded with Gulf moisture
for another potent upper trough arriving Monday night. The GFS is a
little farther north on a closed low of 544dam with ECMWF not nearly
as deep, but much farther south over the TX panhandle by Monday
evening and both with the QPF starting to ramp up for us once again
during the overnight. Much will linger into Tuesday as the whole
system takes it`s time with a big ridge over the Atlantic seaboard.
More rain we will take, but timing could be bumpy late on Monday for
I-30 and then down our I-20 corridor during Tuesday.
PREV DISCUSSION... /issued 1153 AM CDT Tue Mar 15 2022/
.PRELIMINARY POINT TEMPS/POPS...
SHV 47 73 49 78 / 30 0 0 10
MLU 50 71 48 75 / 50 0 0 0
DEQ 41 74 45 76 / 20 0 0 10
TXK 47 72 50 76 / 20 0 0 10
ELD 46 73 47 76 / 50 0 0 0
TYR 46 74 50 76 / 20 0 0 20
GGG 46 74 49 77 / 20 0 0 10
LFK 47 75 49 78 / 10 0 0 20