Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/03/24
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
710 PM CDT Wed Oct 2 2024
.KEY MESSAGES...
- Cooler air returns Thursday, then will see a warm up Friday with
temperatures 5-10 degrees warmer than normal
- Fire weather concerns return on Friday and Saturday due to warm,
dry and windy conditions. Saturday`s wind gusts have the
potential to reach 40 to 50 mph.
- Dry conditions are expected to continue through the start of
next week.
&&
.UPDATE...
Issued at 706 PM CDT Wed Oct 2 2024
With diminishing winds and rising relative humidity values, have
allowed the Red Flag Warning to expire. No other changes made to
the forecast at this time.
&&
.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 130 PM CDT Wed Oct 2 2024
At the present time (115 pm), a cold front is progressing southeast
through east central SD and will depart the CWA shortly. Behind the
front, northwest winds are gusting to 25-35 mph, with the strongest
winds thus far in north central SD. With the above normal
temperatures and dry air in place, RH values are in the upper teens
over central SD and the low to mid 20s over the rest of the area.
Thus, the existing Red Flag Warning is looking to be in good shape
(may be a few areas in east central SD that will be iffy on the 3hr
period of winds) and will let that continue into the early evening.
Looking to the west, there is an ongoing fire near the ND/SD border
north of McLaughlin that is producing a smoke plume to the
Glenham/Selby area and a much stronger fire in northern WY that is
producing a large amount of smoke that is heading this way. That
matches up with the HRRR smoke output, so have added some adjustment
to the cloud cover for tonight into Thursday to indicate at least
some influence on areas that don`t have existing cloud cover.
For the forecast period, a west to east jetstream is in place along
the US/Canadian border at this time (80kt jet streak along
MT/ND/MN/Canada border), but will see some buckling of the jet
tonight. This is due to southward moving shortwave energy from
northern Canada and a deepening trough in the northern Pacific,
which will amplify the trough over the Northern Plains on Thursday.
Associated with the shortwave energy, there is a pocket of 700-600mb
moisture along a west-east boundary at that level over SD late
tonight into Thursday, with winds turning southerly at 700mb over
southern SD and aiding increased warm air advection. So the support
is there for both clouds and potentially some precipitation
development. The limitation looks to be the dry air below 700mb,
which will likely evaporate the precipitation before reaching the
surface. That expectation can be seen in the CAMs, which all have a
band of increased Comp Reflectivity values from north of the Black
Hills and stretching through northeastern SD, but no accumulated
precipitation from it. Thus, will keep PoPs below mentionable and
highlight the increased cloud cover from it. Back to the surface
features for Thursday, a high will follow the previously mentioned
ridge to the ND/SD border near Lake Oahe by Thursday afternoon. This
will bring a brief break from the stronger winds we`ve been seeing
recently, before stronger winds return again on Friday.
There is some concern for frost/freeze conditions on Thursday night
into Friday morning. The surface high will be centered over
northeast SD on Thursday evening, leading to calm winds. With the
abundant dry air and dewpoints in the lower 30s, should be a good
radiational cooling night for the James River Valley and eastward
and expect a quick fall to temperatures. The biggest question will
be if the high shifting east into central MN overnight will be
enough to have the return flow offset the falling temperatures. With
the pressure gradient not really tightening up until the morning
hours (primarily in central SD), do think we`ll get some areas with
lows in the low-mid 30s over the James River Valley and eastward.
Thus, have added a frost mention to locations that are coldest.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 130 PM CDT Wed Oct 2 2024
Upper level ridge will move eastward on Friday, but will allow for a
plume of warm, dry air aloft to move into the area Friday evening
into Saturday morning. 850mb temperatures will reach upwards of 20
degrees Celsius, which is greater than the 99th percentile for this
time of year. Temperatures Friday and Saturday will be in the 70s,
which is 15-20 degrees above normal for this time of year. Low
temperatures Friday night will also be significantly above normal,
only dropping into the mid-50s.
A shortwave will move into the area on Saturday and move a cold
front across South Dakota Saturday afternoon. This front does not
bring any significant chances for rainfall, and the main impacts
will be temperatures dropping and a wind shift. Ahead of the front
in the warm air advection regime, southwest winds will be out of the
southwest at 20-25 knots. After frontal passage however, winds veer
to the northwest and will increase to 30 knots sustained and gusting
40-50 knots. Euro ensemble guidance gives a greater than 50% chance
of winds gusting above 45mph (wind advisory criteria) on Saturday
afternoon across most of the forecast area, with the best chances
across north central South Dakota. The NBM is even more aggressive,
painting a broad 90-100% chance of that threshold being met over the
entire forecast area. Dry conditions (PWATs below normal at 0.5
inches or lower) both ahead of and behind the front coupled with the
winds give concern for fire weather for both Friday and Saturday,
although Saturday looks to be much more impactful.
The shortwave will move out of the area Sunday as another ridge
builds over the western United States. Cluster analysis shows a high
level of confidence in this ridge persisting through the rest of the
forecast period, meaning another dry week with above normal
temperatures is in store for South Dakota. Should this forecast pan
out, it will mark approximately two weeks of no rainfall across most
of the area, with some areas approaching three weeks. At present,
70% of South Dakota is at a level D0 (abnormally dry) or higher,
while 35% of the state is at a level D1 (Moderate drought) or higher
according to the National Drought Mitigation Center. With dry
conditions persisting, the state is likely to see these numbers
increase and the categories increase. Fire weather will remain a
concern next week, particularly in west and central South Dakota
where relative humidities will be the lowest. Winds will not be
nearly as strong next week as on Friday and Saturday however, and so
fire weather impacts may be lower.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 624 PM CDT Wed Oct 2 2024
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail across the area tonight and through
the day Thursday. Elevated smoke will be over the region this
evening, with no vsby reductions expected.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Parkin
SHORT TERM...SRF
LONG TERM...BC
AVIATION...Parkin
Area Forecast Discussion
National Weather Service State College PA
1046 PM EDT Wed Oct 2 2024
.SYNOPSIS...
* AM fog will cover much of the area into the morning
* Rain showers return Sunday night into Monday followed by
cooler temperatures/frost risk Tuesday and Wednesday
* After a cloudy and wet end to September/start to October, a
much drier weather pattern is expected for the next 7 days
&&
.NEAR TERM /UNTIL 10 AM THURSDAY MORNING/...
The drizzle keeps on giving. Even after sliding eastward this
evening, the residual mstr has helped make it super-easy for fog
to form now. The fog kicked in very quickly, showing up in the
north- central counties barely after 00Z/8 PM. It is filling in
the valleys quickly and is spreading out to more than the
"normal" valley fog we see many mornings. Posted a dense fog
advy for most of the area thru 10AM. Have chosen to leave out
the eastern and far NWrn zones for the time being. The clouds
and drizzle are not a certainty to leave the places east of the
Susq R, and the NW did have a couple of hours to dry (into
lower 40 dewpoints) before sunset. However, I can easily see
many of those zones filling in and perhaps needing a advy later
tonight. The mid shift will be able to monitor trends in
clearing and fog expansion.
&&
.SHORT TERM /10 AM THURSDAY MORNING THROUGH SATURDAY/...
Locally dense fog in the morning will give way to returning
sunshine across the western 1/2 to 3/4 of the CWA on Thursday.
However, it appears low clouds will be hard to erode in the
southeast and could linger for most of the day -- which could
result in lower max temps. On balance, highs trend 5-10F warmer
than today into the mid 60s to lower 70s.
Low clouds are forecast to expand across much of south central
PA Thursday night into Friday morning. Expect a combination of
low stratus and valley fog to kick of the first Friday of
October. It`s conceivable that low clouds remain over the
southeast zones on Friday given lingering frontal zone, no
influx of dry air or west wind kicker: another downside risk to
max temps for Day 3. Some guidance even suggest an isolated
shower cannot be ruled out along the aforementioned frontal
boundary through Friday afternoon. The boundary finally pushes
to the east Friday night which should finally allow for clearing
over the eastern zones. Expect valley fog to develop into
Saturday morning.
The center of high pressure/sfc ridge axis arrives on Saturday
and should provide the first nice day with sunshine and pleasant
conditions for ALL of central PA. Max temps top out in the
65-75F range with comfortable humidity.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Fair and seasonable weather appears likely this weekend, as
surface high pressure builds across the state. We`ll continue to
slightly undercut NBM min temps Saturday night, when conditions
favor efficient radiational cooling directly under the surface
high. This will also be favorable for morning fog across typical
fog prone areas across the Commonwealth through the weekend.
Increasing clouds ahead of the next chance of showers are
expected Sunday night as a cold front approaches central
Pennsylvania. Recent guidance indicated a slightly slower
progression so have trimmed PoPs Sunday night and focused the
bulk of rainfall in the overnight period into Monday with
highest chances across northern PA where shortwave interactions
outline the best chances of showers. Instability will be limited
to Sunday night/early Monday morning across the western
highlands so have retained SChc of t-storms in this period with
mentions of storms taken out east of the Allegheny Front.
Lingering showers across N PA will continue throughout the day
on Monday, generally limited to the northern tier. Guidance does
outline high pressure beginning to build into the area late
Monday and into the mid-week allowing for drier conditions to
prevail. The area will remain under the influence of high
pressure Tuesday night into Wednesday morning, where a declining
trend in cloud cover in subsequent guidance runs, cooler
temperatures, and light winds start to bring the first concerns
of frost into the forecast across the northern tier. At this
time, there still remains some uncertainty given some
variability in cloud cover/temperature runs throughout recent
model guidance.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
For tonight, a brief (~1-2 hr) period of VFR conditions will be
possible across airfields with the exception being MDT/LNS.
Clouds are quickly clearing behind the front, but some low
clouds seem to be stubbornly holding on in the Lower Susquehanna
valley. Fog formation is expected to impact airfields
(especially north- central PA), outlined in RAP model soundings
and GLAMP guidance. At this time, have outlined LIFR at all
airfields outside of BFD (SKC/drier air behind the front and
more time to dry out) and MDT/LNS (drier air in the lower levels
might keep concerns at bay) through 12-14Z Thursday.
Around 12-14Z Thursday, fog will begin to mix out, giving way
for VFR conditions with light winds with high (~80%) confidence
with the main concern being some residual fog at UNV/JST in the
14-15Z timeframe. Afterwards VFR will become predominant across
all airfields for Thursday.
Outlook...
Fri-Sat...Drier weather, with primarily VFR conds expected
outside of patchy morning valley fog.
Sun...VFR, no sig wx.
Sun PM-Mon...SHRA moves in west-to-east, some TSRA possible.
&&
.CLIMATE...
Total precipitation for the month of September was 1.11 inches
at Williamsport (-3.65" below average) which ranks as the 11th
driest on record.
The average temperature for the month of September was 63.1
degrees at Bradford (+4.2F above average) which ranks as the
warmest September on record.
Harrisburg (MDT) reported its 9th straight day of measurable
rainfall on Tuesday, dating back to Monday September 23rd. This
ties the record for longest such stretch tying the record set
from April 7-15, 1893 and matched May 15-23, 1893 and July
28-August 5, 1971. If MDT reports at least 0.01" of rain on
Wednesday October 2nd, it will set the record for most
consecutive days with measurable rainfall.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM EDT Thursday for PAZ006-010>012-
017>019-024>028-033>037-041-045-046-049-050-056-063.
&&
$$
SYNOPSIS...Dangelo/Steinbugl/Banghoff
NEAR TERM...Dangelo/Steinbugl/Banghoff
SHORT TERM...Steinbugl/Banghoff
LONG TERM...NPB/Bowen
AVIATION...NPB/Bowen
CLIMATE...Steinbugl/Banghoff
Area Forecast Discussion
National Weather Service Des Moines IA
1047 PM CDT Wed Oct 2 2024
...Updated for the 06z Aviation Discussion...
.KEY MESSAGES...
-Very High to Extreme fire weather conditions forecast for this
afternoon to early evening across the north-northwest, with a Red
Flag Warning in effect until 7 pm this evening.
-Very low precipitation chances (<10%) associated with a weak, upper
level wave across the far east and southeast Thursday evening into
early Friday. Friday will see pleasant conditions.
-Warm weather returns for Saturday with highs in the mid 80s to
low 90s, with precipitation chances (>15-20%) possible across
the far northeast as a frontal boundary moves through.
&&
.DISCUSSION...
Issued at 248 PM CDT Wed Oct 2 2024
Short Term:
GOES-16 satellite imagery shows relatively clear skies this
afternoon as a surface high continues to move southeastward away
from Iowa. A tightening pressure gradient was also observed across
northern Iowa just ahead of a boundary draped across southeast South
Dakota. Winds have been quite gusty across the north, with KEST
gusting up to 41 MPH. These gusty winds in combination with the low
relative humidities, warmer temperatures and dry fuels has lead to
very high to extreme fire danger across portions of northwest and
northern Iowa. Soundings also show a well mixed layer developing
late this afternoon, which may be able to tap into 925mb winds. RAP
model output shows the 925mb wind field around 30 kts across the far
north, with values lowering towards southern Iowa. Thus an upgrade
from the previous Fire Weather Watch to a Red Flag Warning occurred
this morning that is in effect until 7pm, which was coordinated with
neighboring offices. Please refer to the Fire Weather section of
this discussion for more details. With ample warm air advection and
mixing, highs today will reach the mid 80s west to upper 70s across
the east. Winds will begin to subside at sundown as peak mixing
begins to decrease. A weak boundary moves through late tonight into
early Thursday with flow becoming northerly. By late Thursday into
Friday, a weak upper level wave moves across Iowa. QG forcing will
overspread the area, but the best moisture transport appears farther
east away from our CWA. This leads to very minimal chances for rain
across our far east, but appears unlikely at this time, as BUFKIT
soundings show a rather deep dry layer aloft.
Long Term:
Friday will see high pressure settling in again across the area,
leading to pleasant conditions with high temperatures in the mid to
upper 70s. A thermal ridge will begin to move toward our area by
later Friday into Saturday, resulting in a rather drastic warmup for
Saturday. Latest NBM guidance continues to show highs for Friday
above the 75th percentile in the mid 80s to low 90s, most likely
driven by the GFS output overmixing resulting in hot temperatures.
Cloud cover is forecast to be minimal, thus mixing may be more
enhanced and increase temperatures. By Saturday evening, a frontal
boundary will move through the state, with QG forcing overspreading
the area associated with an upper level trough. A ribbon of moisture
is evident and with forcing entering the area, we may see PoPs
return. Soundings are consistent in another dry layer aloft that may
hinder precip chances, however, with the NBM focusing the best
probabilities northeast of our forecast area. Another thermal ridge
will form across the western CONUS next week and will gradually move
eastward toward the forecast area. CPC 6-10 day and 8-14 day
outlooks highlight this by showing above normal temperatures for the
area, with below normal precipitation also forecast.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1047 PM CDT Wed Oct 2 2024
VFR conditions are forecast through the current TAF period. Model
guidance suggests the potential for a few showers and storms late in
the period, mainly east of I-35 and after 00z Friday.
Confidence in spatial coverage is very low at this time due to
an abundance of dry air, but trends will need to be closely
monitored.
&&
.FIRE WEATHER...
Issued at 248 PM CDT Wed Oct 2 2024
Weather conditions have generally played out as expected so far
this afternoon in terms of RH values and winds, though over the
past few hours have seen higher wind gusts across the
north/northwest with gusts upwards of 35-40mph, given the
overperformance of mixing that has occurred. With these winds a
bit further east across the remaining northern tiers of
counties, have expanded the RFW as a result over the respected
area, which will continue until 7pm. Still seeing dry and breezy
conditions allowing for elevated fire weather concerns into
central Iowa, while further south winds have been well below
criteria despite similar dry conditions. Conditions are expected
to improve later this evening as the pressure gradient relaxes
and mixing ceases, along with increasing RH values.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Bury/Castillo
AVIATION...Martin
FIRE WEATHER...Bury
Area Forecast Discussion...CORRECTED
National Weather Service Memphis TN
952 PM CDT Wed Oct 2 2024
...New UPDATE...
Issued at 948 PM CDT Wed Oct 2 2024
Clear skies and generally calm winds prevail across the Midsouth
at 9 PM. Temps had cooled into the 50s in most locations, a few
degrees above current dewpoints. Patchy fog will remain possible
toward morning, near the TN River. 12Z HREF and latest HRRR also
suggest possible fog development over the delta of east central AR
and northwest MS toward sunrise. Current forecast has these scenarios
covered well.
PWB
&&
.SYNOPSIS...
Issued at 206 PM CDT Wed Oct 2 2024
A largely benign weather pattern will continue across the Mid-
South over the foreseeable future. Temperatures will begin to
warm slightly into the 80s beginning on Thursday and continue
through Sunday. Temperatures will cool back down by next week,
generally spanning the 70s through midweek.
&&
.DISCUSSION...
(This evening through next Tuesday)
Issued at 206 PM CDT Wed Oct 2 2024
A beautiful day continues across the Mid-South, with a clear sky
and temperatures warming into the upper 70s to near 80. Surface
high pressure will continue to drift eastward overnight, with calm
conditions expected. Dew point depressions will remain at or
below a few degrees overnight, plus with calm winds and clear
skies some patchy fog could develop. Best chance would likely be
for areas generally in the eastern half of the CWA and/or near
bodies of water. Any fog that does develop overnight will quickly
mix out after sunrise in the morning.
Weak, upper-level trough will begin to develop Thursday to the
west, allowing for southwesterly flow aloft to return to the area
briefly. This will bring some additional WAA back to the region
and cause temperatures to rise above normal, into the mid 80s, by
Friday through the weekend. A weak shortwave will pass to our
south/southeast on Friday, that could bring some additional
cloudiness and maybe a shower or two across northeast MS.
Otherwise, dry conditions are expected to prevail through the
weekend. Weak cold front will pass through the area on Monday,
allowing temperatures to drop back down to near to below normal.
As things stand, rain chances remain very low and this will likely
be a dry frontal passage. High temperatures into next week will
generally span the 70s, with overnight lows in the 50s.
&&
.AVIATION...
(00Z TAFS)
Issued at 602 PM CDT Wed Oct 2 2024
VFR conditions will continue for the entire forecast period. Winds
will be light from the northeast tonight becoming more from the
southeast on Thursday.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...CMA
AVIATION...ARS
Area Forecast Discussion
National Weather Service Marquette MI
730 PM EDT Wed Oct 2 2024
.KEY MESSAGES...
- Enhanced fire weather conditions today with gusty winds and a
very dry airmass.
- Southerly wind gusts to 20-30mph common, with a 50% chance for
stronger gusts to near 40mph especially in the western UP.
- Abnormally dry and moderate drought conditions have been
expanding across Upper MI. Over the next 2 weeks, there are
no signs of a transition to a more typical fall pattern that
would bring frequent precipitation. Drought likely to expand
and deepen over the next 2 weeks with fire weather a concern
on windier days.
- Only potential of rainfall over the next 7 days occurs Saturday
night and Sunday. Widespread, significant rainfall not
expected.
- Frost potential for Thursday night and Friday night.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 205 PM EDT Wed Oct 2 2024
GOES-16 water vapor imagery shows some high clouds over an otherwise
dry low level airmass ahead of a cold front over north-central MN
per RAP Analysis. With nearly a 10mb pressure gradient across the
entire UP, gusty SW winds have been observed across the UP and Lake
Superior, with the highest gusts so far at 16Z being a 46 mph gust
at Granite Island near Marquette and gusts of around 43 mph on Isle
Royale. Additionally, clearing skies especially across the south-
central UP have contributed to efficient mixing and falling RHs,
with the Iron Mountain ASOS showing RH values of 28 percent at 17Z.
Gusty winds and dry air both are combining for enhanced fire weather
conditions today, so obey all burn bans! The dry air at the surface
is also contributing to any prefrontal precipitation evaporating
before making it to the surface, with MRMS precip estimates showing
0 precipitation over the UP since 07Z despite a number of radar
returns on the KMQT radar. Expect these conditions to persist
through the evening hours, with highs around the 70 degree mark.
Tonight, as the cold front passes through the UP, overnight boundary
layer stabilization should help keep post-frontal winds somewhat
limited. Clear skies will allow temperatures to fall close to the
dew point tonight , but the coldest spots are only expected to be in
the upper 30s, so patchy frost is not forecast for tonight.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 353 PM EDT Wed Oct 2 2024
While a more active pattern is expected over the extended period,
expect these next several days to be fairly dry, save for Saturday
night into possibly Monday, when a Clipper low brings some rainfall
to the area this weekend, which could be quickly followed by light
lake-effect rainfall early next week. Otherwise, expect temperatures
to still average above normal for early October, with highs
generally in the 60s and lows in the 30s and 40s.
Expect mostly sunny skies to start out Thursday, before mid-level
cloud cover develops overhead across the central and east during the
latter half of the day as upper-level diffluence from the right-
entrance region of the 130 kt jet streak overhead creates some
atmospheric uplift. However, with high pressure over the Central
Plains cutting us off from Gulf moisture, expect the area to remain
dry Thursday, with cloud bases struggling to get below 4 kft due to
the lack of precipitable water. That being said, there is a 10 to
20% chance that we could see some rain drops/sprinkles over the
south central and east Thursday afternoon and evening provided there
is enough moisture to get through the 4 kft dry layer. In addition,
given the dry conditions at the sfc, we may see min RHs get down to
or below 30% for a few hours during the afternoon in the south
central. However, given that temperatures Thursday are only expected
to get into the 60s and winds are expected to be fairly light (10
mph or less), no or only limited fire weather concerns are expected
over the south central. While not under fire weather concerns, the
Keweenaw does look to be the exception in regards to windiness
Thursday, with westerly winds gusting up to 30 mph at times by the
afternoon given the fetch over Lake Superior and local topographical
effects.
Moving into Thursday night, expect skies to clear out and for winds
to become somewhat calm. This is an ideal setup for frost to form
over the interior west; lows are projected to get down into the
lower to mid 30s, and with radiational cooling ongoing throughout
the overnight hours, we could see some areas in the interior west
become blanketed with frost. Therefore, if you live in the interior
west, you will want to protect your vulnerable plants. Elsewhere,
expect the lows to get down into the upper 30s to lower 40s.
Expect a near repeat for Friday and Friday night as the high
pressure center moves through the Upper Great Lakes. However, winds
may be even weaker on Friday as the center of the low approaches
from the west-southwest. Otherwise, additional frost is expected
Friday night, with the frost potential expanding into the interior
central and east too.
As we head into Saturday, WAA ahead of a cold front associated with
a shortwave moving through the Canadian Prairies brings high
temperatures back into the mid 60s to lower 70s, with cloud cover
increasing from the west late in the day. While a mid-level high
stretching from the Southern Plains to Southeastern U.S. will still
keep us cut-off from Gulf moisture this weekend, given the
strengthening of the low with time and the lift associated with the
cold front, we could see some rain showers along the frontal
boundary Saturday night into Sunday morning. While we may hear a few
rumbles of thunder and shearing is high along the front, given the
lack of CAPE, no thunderstorms are expected. However, with the
forcing along the front being fairly vigorous, there may be enough
uplift to create some glaciation in the upper levels and thus
lightening. Therefore, I`ve capped thunder chances at slight (15-24%
chance) Saturday night and Sunday morning along the front. Overall,
while this rainfall will be enough to wet the ground, due to the
lack of precipitable water available via the lack of Gulf moisture,
rainfall amounts are expected to be generally less than half an inch
(5 to 30% chance according to the latest LREF run), with the most
rainfall falling in the east. In addition to the rain showers,
expect gusty southerly winds Saturday and northwesterly winds Sunday
and Monday. Behind the cold front, we could also see some light lake-
effect/upslope rain showers over the northwest wind belts Sunday
into Monday, as the 850 mb temperatures fall to near 0 C and lake
temperatures are currently near 14 C; these days are also going to
be our coolest, with highs only reaching the mid 50s to maybe the
lower 60s. However, as ridging builds in from the Plains early next
week, expect the lake-effect rainfall to progressively end from west
to east early next week. High pressure ridging and dry weather
returns by the middle of next week and looks to hold on until next
weekend as an omega block progressively develops and moves through
the central CONUS.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 729 PM EDT Wed Oct 2 2024
VFR conditions to prevail for the duration of TAF period. Main
threat continues to be strong winds initially out of the southwest,
then shifting to the west-northwest by early tonight with cold front
passage. Winds could gust up to 30 kt along with a LLWS threat
at SAW after Thu 03Z.
&&
.MARINE...
Issued at 353 PM EDT Wed Oct 2 2024
Southerly gales to 35 kts over the eastern lake this afternoon
weakens to northwest winds of 20 to 25 kts late tonight as a cold
front passes through Lake Superior. A weak shot of CAA Thursday
brings westerly winds of 20 to 30 kts back over the western and
central lake in the afternoon before dying back down to 20 kts or
less late as ridging moves back over the Upper Great Lakes. However,
the ridging is fairly transient, with troughing moving in from the
west bringing west to southwest winds of 20 to 25 kts back across
the western half of the lake Friday afternoon. Winds increase again
Saturday as a low pressure moving through the Canadian Prairies
brings a cold front through the Northern Plains. As this cold front
approaches, winds from the south will build to gales of 35 to
possibly even 40 kts by early Saturday evening. Once the cold front
moves through Saturday night, expect the gales of 35 to 40 kts to
come from the west and northwest; a few rumbles of thunder are
possible along the frontal boundary (around 20% chance of thunder).
These gales could continue until late Sunday night/early Monday
morning. Strong northwesterly winds of 20 to 30 kts with a few gale
force gusts up to 35 kts possible over the east half are expected to
continue until late Monday, when ridging pushing in from the west
progressively slows the winds down to 20 kts or less late Monday
night/early Tuesday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
Gale Warning until 2 AM EDT Thursday for LMZ248-250.
&&
$$
SHORT TERM...GS
LONG TERM...TAP
AVIATION...GS/TDUD
MARINE...TAP
Area Forecast Discussion
National Weather Service Raleigh NC
920 PM EDT Wed Oct 2 2024
.SYNOPSIS...
A weak backdoor front will drop southward through central North
Carolina tonight, followed by high pressure nosing in from the north
Thursday through Friday. A cold front will move west to east through
the area late Saturday, with weak high pressure returning Sunday. A
much stronger cold front will sweep through the region late Monday,
bringing in a cooler and drier air mass that will persist through
the middle of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 920 PM Wednesday...
With the evening update, the radar has gone quiet locally, and model
guidance does not show any isolated showers developing through the
rest of the night. Therefore, have gone ahead and removed the slight
chance of showers from the forecast. Also tweaked hourly temperature
and dewpoint grids - think that some northeastern areas might manage
to dip into the upper 50s. Previous discussion follows.
As of 140 PM Wednesday...
Daytime mixing of the drier air to surface will lead to partial
scattering of the widespread stratus cloud layer into a stratocu
layer by the afternoon. The filtered afternoon sunshine should allow
daytime highs to rebound 2-5 degrees, ranging from mid 70s north to
lower 80 south.
A weak lobe/channel of vorticity currently diving ESE across the
region is producing some spotty shower activity across the Piedmont.
These showers should dissipate with loss of heating and nocturnal
cooling/increasing BL Cin.
Surface pressure rises associated with a weak parent high building
east into the mid-Atlantic states will help to propel a weak cold
front/surface trough into the area during the afternoon and evening.
Spotty light rain/drizzle could linger into the evening and
overnight hours, again mainly across the northern Piedmont, in a
weak H9 easterly upslope regime where low-level saturation is
deepest. Otherwise, stratus and patchy/areas fog is expected again
tonight/Thursday morning. Lows 60-65, with some upper 50s possible
in the rural/outlying areas across the northern Piedmont.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 204 PM Wednesday...
High pressure at the surface will extend into our region from off
the New England coast. This will bring an east to northeast flow.
Aloft, ridging over the far SE US will slowly move offshore. In its
wake, a disturbance in the northern Gulf will track into AL/GA by
early Fri.
The airmass will be similar to that of Wed, supporting highs
slightly above normal in the upper 70s to low 80s. Morning low
stratus over the northern and northwest Piedmont should mix out to
partly cloudy skies. Models and some high-resolution CAMs, most
notably the HRRR and NAM-NEST, show some very isolated showers
developing in the aftn to early eve over the far NW Piedmont and
into the Foothills. Model soundings show some weak instability
beneath a subsidence inversion. This weak instability and upslope
flow could favor these widely isolated to spotty showers over the
Triad. Otherwise, we are dry for the day.
Overnight, low stratus looks to develop once again, mainly across
the far NW Piedmont into the Foothills of NC. Upslope flow in the
925-850 mb layer could support some isolated rain or drizzle over
the Triad and into the NC mountains. Lows will remain above average
but cooler than the past few nights. Expect lows in the low 60s in
the west under more low stratus, to the upper 50s to near 60 in the
east with more clearing.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 250 PM Wednesday...
Mid and upper level ridging will shift offshore Friday followed by a
shortwave trough moving across the OH valley and off the new England
coast late Saturday. Between these features a plume of upper level
moisture will move across the region resulting in mostly cloudy
skies Friday and Friday night. Ridging across the eastern US takes
over late Saturday and Sunday before another wave of upper level
moisture move across the region Monday and Tuesday.
At the surface, high pressure will influence the region with
generally dry weather. A few isolated light showers in the
afternoon/evening Friday are possible with some mid level moisture
and some upslope flow along the mountains. The activity could stay
to the NW but wouldn`t be surprised if some showers move across the
NW Piedmont region. As the trough moves across the TN and OH valley
Saturday a surface boundary will shift to the southeast across NC
late Saturday early Sunday. Ensemble guidance is showing the front
to be dry as it moves across the region, with most of the moisture
to the south. After that, another high pressure building across the
Central Plains will shift across the MS valley bringing a stronger
dry cold front across the region. Again this is expected to be dry
as the front moves across NC bringing a taste of fall to the region.
Temperatures will be above average Friday through Monday with highs
generally in the mid 70s to low 80s. After the front moves through
sometime Monday, expect refreshing fall like temps with highs in the
low to mid 70s Tuesday and upper 60s to low 70s Wednesday. Lows
Tuesday and Wednesday will be in the upper 40s to low 50s.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 740 PM Wednesday...
Confidence is high that adverse aviation conditions will develop
after 06z tonight across all of central NC, as the combination of
moist low levels, very light to calm surface wind, and lack of
higher clouds to facilitate low cloud development, along with patchy
MVFR fog. MVFR cigs are expected to form after 06z before dropping
to mostly IFR after 08z, with the highest confidence at INT/GSO/RDU.
These low cigs should last until at least mid morning, but cigs are
likely to improve very slowly at INT/GSO, not reaching MVFR until
around 15z and not reaching VFR until after 19z. Cigs at RDU/RWI/FAY
should improve to MVFR then VFR by 14z and 17z, respectively. Apart
from a potential isolated shower near INT/GSO after 18z Thu,
conditions will remain mostly dry. Surface winds will remain light,
under 8 kts, from the NE or E.
Looking beyond 00z Fri, another round of late-night sub-VFR
cigs/vsbys is possible at INT/GSO 08z-13z early Fri morning, but
otherwise, VFR conditions should hold over central and east areas
through early next week, with mostly low rain chances. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Green/CBL
SHORT TERM...Kren
LONG TERM...CA
AVIATION...Hartfield