Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/24
Area Forecast Discussion
National Weather Service La Crosse WI
558 PM CST Wed Nov 13 2024
.KEY MESSAGES...
- Scattered showers continue to develop, but generally weaken
as they move northeast. Rainfall amounts through tonight have
decreased with most locations less than 0.10" (HREF
probabilities for 0.10" now 0 to 50%).
- Dry conditions and warmer temperatures (10 to 15F above
normal) with highs in the mid to upper 50s for the end of the
week.
- Weather pattern turns more active for next week as rain
chances (50 to 70%) return late Monday. Some potential for
accumulating snow as the storm exits east for the middle part
of next week, along with much colder air.
&&
.DISCUSSION...
Issued at 157 PM CST Wed Nov 13 2024
Overview:
A mid-tropospheric trough of low pressure was located over the
Plains with a north to south area of surface low pressure located in
the same area. The KARX VAD wind profiler shows the low level flow
through 3kft was generally from the southeast with veering winds
aloft; gradually working to moisten top down. As a result of the
storm system being so far west and the dry air in place, with the
weakening of the system as it moves east, the rainfall area has
become narrower with time and slow to move east.
Temperatures were in the 40s to around 50 at 19Z.
Scattered showers continue to develop, but generally weaken as they
move northeast. Rainfall amounts through tonight have decreased
with most locations less than 0.10" (HREF probabilities for 0.10"
now 0 to 50%):
Moisture transport vectors weaken over our local area and increase
over the Tennessee River Valley toward Illinois. As a result, the
CAMs weaken the rain band through 03Z over Minnesota with the new
area of rain developing over parts of eastern Iowa, Illinois, and
southern Wisconsin. The bulk of the rainfall is forecast to be less
than 0.10". HREF probabilities for 0.25" or more quite low; 0 to
10%. Rainfall continues to push east tonight for most of our local
area by 12Z. The closed low over parts of the Missouri River Valley
is progged to slowly track toward the Mid-Mississippi River Valley
through Thursday morning. Ridging builds in quickly builds in for
Thursday. Above normal highs are forecast for Thursday in the 40s to
lower 50s with a mix of clouds and sunshine.
Thursday - Sunday: Above Normal Temperatures, Rain Chances?
Shortwave ridging enters the area helping to keep conditions mostly
dry through the weekend. High temperatures will be 10 to 15 degrees
above normal, which equates to highs in the mid to upper 50s.
Heading into Saturday night into Sunday morning, a shortwave trough
moves north of the region. This will bring a low chance (20 to 40%)
of rain, primarily in Wisconsin. The caveat to this rain chance is
that the GEFS members are mostly dry while the EPS has about half
its members showing precipitation occurring. Compared to the
previous forecast there is a trend of fewer EPS members showing
precipitation. If this precipitation occurs, only a couple hundreths
of rain would fall.
Monday - Wednesday: Rain, Potential for Snow?
Deterministic and ensemble guidance continues to show a shortwave
trough moving out of the desert southwest and impacting the Upper
Midwest. This trough is then forecasted to merge with the apparent
longwave trough. At the moment both deterministic runs of the GFS
and ECMWF show this merger happening over the Upper Midwest early
next week. This would prolong the effects of the storm system.
Differences in exact path of the low coming out of the southwest and
strength of it continue to exist. Regardless, the majority of
ensemble members, about 90% of EPS and GEFS members show
precipitation occurring. Ensemble clusters show a good percentage,
about 85% of all ensemble members, of this trough influencing the
area through the middle of next week. As this system moves through,
rain will be precipitation type, however as the storm exits, cold
air will wrap around and snow will be possible! Current ensemble
guidance shows around a 40 to 60% chance of measurable snow on
Wednesday. Given the complex synoptic setup, there are plenty of
things that need to be worked out, so continue to monitor as we get
closer to next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 558 PM CST Wed Nov 13 2024
Sporadic showers can be noted on radar across portions of the
region this evening as a weather disturbance passes south of
the area. Currently, bkn to ovc VFR cigs can be noted across
much of the region with MVFR/IFR cigs across northern IA and
southern-central MN. As we continue through the evening and into
the overnight hours, intermittent showers will give way to
increasing low-level saturation and falling cigs. As a result,
expecting cigs to fall to MVFR and eventually IFR levels at
KRST. With some weak lift in this layer shown in recent RAP
soundings would not be able to rule out some light drizzle which
may reduce vsbys some as well. Low cigs will continue through
the morning hours until some weak mixing allows cigs to improve
marginally at KRST to MVFR. There is some potential that cigs
could drop to LIFR (20-40% chance) at KRST overnight. However,
given the lower confidence of this in guidance opted to hold off
on any mention at this time. Winds will start the TAF period
from the east and will shift to the northwest during the
overnight hours.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Cecava/Zapotocny
AVIATION...Naylor
Area Forecast Discussion
National Weather Service Cleveland OH
1023 PM EST Wed Nov 13 2024
.SYNOPSIS...
A low pressure system tracks through tonight into Thursday. High
pressure returns late Friday into the early part of the weekend.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
9:30 PM Update...
Timing of rain showers remains on track. Dry air continues to
win out so far, with virga over NW Ohio, so still think rain
will hold off until 05 or 06Z. Otherwise, SE winds are
increasing as the gradient tightens. The latest NAM and RAP
continue to project a 40-50 knot low-level jet moving through
with the warm front overnight, so expect downslope areas of the
NE Ohio lakeshore and NW PA to see the strongest winds. All of
these areas will gust over 40 mph, but lakeshore areas of NW PA
will see gusts to 50 mph, so the Wind Advisory remains in
effect overnight.
6:30 PM Update...
The forecast remains on track for this evening with no changes.
Rain is expanding to the west and southwest across Indiana and
southwest Ohio as warm/moist advection and isentropic ascent
increase ahead of the warm front. Dry low-levels will cause this
to initially fall as virga across our area, so think timing is
still reasonable of the rain reaching the I-75 corridor between
05 and 06Z then gradually spreading east overnight. The
observations will be monitored over the next couple of hours in
case rain reaches the surface earlier than expected.
Original Discussion...
Upper level trough digs into the Ohio Valley with surface low
pressure tracking into the southern Great Lakes region tonight into
Thursday. Currently in the midst of an increasing pressure gradient
with high pressure retreating into eastern Quebec/Labrador.
Southeast winds will be on the increase as a result this evening and
especially into tonight. Downsloping areas will be affected most,
mainly Cleveland and east closest to the lakeshore. In the northern
part of Erie County PA, where downsloping is greatest, a Wind
Advisory has been pushed mainly for the overnight period into early
Thursday. Back to the west, showers push into the western zones
generally after 06Z, although some brief light showers could appear
ahead of time, but the main batch of rain will be an overnight
feature. General thunder just south of the CWA, and will continue to
leave it out of the forecast at this time. Not a particularly
oversaturating rain by any means, and looking at half to three
quarters of an inch for the western half of the CWA, and slightly
less for the eastern half as the low pressure system slowly weakens
moving through the CWA. It will degrade into an inverted surface
trough, but keep the chances for showers going into Thursday night.
Back to the winds for tonight into the first half of Thursday,
expecting gusts 25-35mph for the bulk of the CWA, 30-40mph Cleveland
lakeshore and east to the PA border, and 40-50mph gusts for northern
Erie County in PA. Winds gradually ease late Thursday into Thursday
night, and will be in the process of shifting around to the north
northwest after 06Z Friday as the surface trough finally makes its
way out of the CWA. Temperatures mid 40s east to lower 50s west for
Thursday but no cold air with this system with a Pacific source
region.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Troughing will persist over the Lower Great Lakes through Friday and
although 850mb temps won`t cool enough for lake effect rain showers,
there may be just enough lake induced instability for some light and
scattered lake-enhanced rain showers. At the very least, cold air
advection over the lake will result in widespread clouds downwind
from Lake Erie Friday. Any showers will completely taper off Friday
night as an upper ridge and surface high build in from the west.
This ridge will settled over the region through the remainder of the
Short Term Period and expect dry weather with clearing skies through
Saturday night.
Despite the cold air advection Friday, high temperatures will still
be in the low to mid 50s with lows in the upper 30s to lower 40s.
Expect similar temperatures for Saturday and Saturday night,
although portions of interior NE OH and NW PA will likely dip into
the lower 30s Saturday night.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Southerly flow will develop as the upper ridge axis and a surface
warm front cross the local area early Sunday and expect clouds to
increase throughout the day as an upper trough tracks east across
the Upper Great Lakes. Deterministic guidance continues to struggle
with lift/moisture across the area, but scattered showers are
possible as a weak cold front crosses the CWA Sunday night. A brief
lull is anticipated Monday morning and into the afternoon before a
more potent system approaches from the west late Monday into
Tuesday. Still quite a bit to iron out with the track, timing, and
intensity of this system, so have broadbrushed chance to likely PoPs
since most locations will likely see at least some rain on Tuesday.
Additional showers may continue through Wednesday but still far too
much model spread to get specific on precipitation chances.
Above normal temperatures are anticipated Sunday through Tuesday
with temperatures beginning to cool starting on Wednesday.
Wednesday`s highs will depend on the synoptic setup which, as stated
above, still remains murky.
&&
.AVIATION /00Z Thursday THROUGH Monday/...
VFR will continue at all terminals through early tonight, but
rain is expected to move in from west to east starting around
06Z at KTOL and KFDY then reaching KYNG and KERI by 12-14Z. VFR
will continue at the onset of rain for the first 1 to 3 hours
due to the gusty winds and downslope component, especially in NE
Ohio and NW PA, but MVFR to IFR conditions will eventually
develop. This will take the longest at KERI due to the
strongest downsloping. IFR and occasional LIFR will dominate
Thursday afternoon and evening, but the rain will become more
scattered as the steadiest precip moves east of the region,
leaving scattered showers and drizzle/mist across the region.
So, the overall message is rain moving in late tonight and
Thursday morning, but flight conditions will deteriorate slowly,
with the worst conditions Thursday afternoon and evening.
In terms of wind impacts, SE winds will increase this evening
and tonight, with sustained winds of 15-20 knots and gusts to
25-35 knots developing overnight. Downsloping will bring the
strongest winds to KERI where gusts could exceed 40 knots late
tonight and Thursday morning. Some low-level wind shear is
possible late tonight given a 40-50 knot low-level jet over NE
Ohio and NW PA, but left it out of the TAFs since gusts will be
mixing to the surface. SE winds will subside to 10-20 knots
Thursday afternoon.
Outlook...Non-VFR expected in periods of low ceilings through
Friday. Non-VFR possible in showers Sunday night and Monday.
&&
.MARINE...
Southeast winds of 10-15 knots late this afternoon will increase
tonight and Thursday morning to 15-25 knots which will require the
issuance of a Small Craft advisory. As low pressure approaches the
lake tonight and Thursday, the pressure gradient will increase and
produce downslope winds off the higher terrain inland of the city
Erie, PA. Winds over the lake could reach 30-34 knots over the PA
waters from 09Z-15Z before diminishing in the late afternoon.
Low pressure will track southeast off the Carolina coast on Friday
and strengthen. Winds become northwesterly behind the low but
generally remain 15 knots or less and decrease on Saturday as high
pressure builds over the lake. The high pressure will move to the
southeast states on Sunday as a weak front crosses the lake Sunday
night.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...Wind Advisory until 10 AM EST Thursday for PAZ001.
MARINE...Small Craft Advisory until 5 PM EST Thursday for LEZ142>149.
&&
$$
SYNOPSIS...26
NEAR TERM...Garuckas/26
SHORT TERM...Maines
LONG TERM...Maines
AVIATION...Garuckas
MARINE...Maines
Area Forecast Discussion
National Weather Service Goodland KS
335 PM MST Wed Nov 13 2024
.KEY MESSAGES...
- Above normal temperatures continue through the start of the
weekend; exception being over any snowpack.
- Breezy to gusty winds return favoring the east Friday.
- Active pattern looks to return early next week with rain
chances on Monday and increasing confidence for below normal
temperatures starting the middle of next week.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 100 PM MST Wed Nov 13 2024
A stout 850mb jet is currently across the area which is leading,
along with a departing surface low, to the breezy conditions across
the area. Through the afternoon the winds will slowly decrease west
to east as the jet weakens and moves further off to the east. The
most noticeable decrease in winds will be across the western
portions of the county warning area. Skies will be mainly clear
as developing mid level ridging will lead to subsidence across
the area. Into tonight, am seeing some signs of stratus or maybe
even some localized valley fog across Cheyenne county Colorado
especially southern portions of the county. Temperatures across
Colorado will very interesting to see how they pan out tonight.
Winds are forecast to be from the WSW around 230 degrees which
is in the typical "furnace" wind range which typically helps
keep the area warm. Guidance is suggesting that lows in the low
to mid 20s or even lower will happen which is very interesting
to me. A theory as to this is due to large fetch of the cooler
still snowpacked environment that cooling will be stronger as
the winds will continuously be blowing across that. There also
still could be a cold bias in the models that is leading to the
cooler temperatures and appears that they have been cooler than
forecasted as well since one of our COOP observers in Kit
Carson, Colorado reported a low in the upper teens this morning.
I did nudge temperatures down in the snowpack and just outside
of it while warming the remainder of the area a few degrees.
Thursday, mid level ridging will remain across the area for the
day as southwesterly winds remain around 10 mph sustained. A
gradual shift to the east looks to occur through the afternoon
as we begin seeing some weak moisture advection occurring. Highs
for the day look to be warmer as the southwest wind will be in
place with highs in the low to mid 60s with the exception being
the continued snow pack across Colorado with highs in the low to
mid 40s near Flagler to the low to mid 50s near Burlington.
There does also appear to be a signal for some fog development
along and north of a Sharon Springs to Russell Springs corridor
and on up towards Dundy and Hitchcock county. The signal is from
the continued weak moisture advection along with light winds.
Other visibility models such as the CONSHORT and HRRR also do
support this as well. Am holding off however on introducing
into the forecast to assure no change in the location of the fog
occurs since it is still 36-40 hours out and fog forecasting
can be rather fickle in a conditional setup. If the fog occurs
at this time it looks like it will be from roughly the 06Z- 15Z
Friday timeframe, may also need to keep an eye on freezing fog
potential as well as temperatures are currently forecasted below
freezing.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 100 PM MST Wed Nov 13 2024
Ridging will remain across the area as a trough begins to develop
across the the west. An 850mb jet will again develop mainly across
eastern portions of the county warning area where breezy winds
gusting 35-40 mph are again forecasted favoring the east and south
using the 90th percentile NBM (National Blend of Models) to better
show the stronger winds. Further to the west, assuming the jet
doesn`t trend westerly will gusts from the south around 20-maybe 25
mph. Did increase the temperatures across the area as well due to
the favored southwesterly winds.
Troughing looks to continue through the weekend and into the start
of the new work week. A weak and dry cold front is forecast to move
across the area Saturday night with highs falling into the 50s for
Sunday and Monday. Monday will need to watch for increasing rainfall
chances currently favoring eastern portions of the area with
moderate to potential heavy rainfall occurring as PWATS of 1-1.25
inches move into the area. Any hydrologic issues at this time looks
to be minimal to none as corfidi downshear vectors are around 80-90
knots according the 12Z run of the GFS. Not seeing any concern for
severe weather at this time either due to the lack of CAPE and mid
level lapse rates being around 4-5 C/km. A more modest cold front
looks to move through the area as the trough moving through turns
into a low as this occurs and through Tuesday and Wednesday winds
look to become gusty to even strong at times. Will also need to
watch for the potential for wraparound precipitation with this
front as well as snow would be favored. At this time not seeing
any favored signals for a winter storm but the 11/13 00Z run of
the EFI (Extreme Forecast Index) does show a shift of tails
across eastern Colorado on Tuesday but the number of members is
very small as it is currently a low confidence impactful
potential event. So will need to watch for any potential trends
as there is currently a small (less than 5%) chance of impactful
snow. Virtually all ensemble members of the GEFS and ECMWF all
do favor colder air moving into the area. The AO (Arctic
Oscillation) is also forecasted to become more negative which
does favor colder air moving into the Plains. Wind chills during
this time (at least Wednesday morning) may also approach zero
or maybe even below zero due to continued breezy northerly
winds. So will need to continue to monitor as well for perhaps
some of the coldest air of the season so far.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 335 PM MST Wed Nov 13 2024
KGLD...VFR conditions will continue through the period. A
northwest wind up to 10kts at taf issuance will back to the west
at similar speeds around 03z then southwest around 12z,
continuing through 18z. After 19z, winds become light and
variable.
KMCK...VFR conditions will continue through the period. A
northwest wind up to 10kts at taf issuance will back to the west
at speeds around 6kts by 05z, continuing through 15z. After 16z,
winds become light and variable.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Trigg
LONG TERM...Trigg
AVIATION...99
Area Forecast Discussion
National Weather Service Wilmington NC
731 PM EST Wed Nov 13 2024
.SYNOPSIS...
A cold front will bring widespread showers Thursday into Thursday
night. Low pressure will develop near the Outer Banks and strengthen
as it moves offshore Friday. Dry weather with seasonable temperatures
will develop Friday into Sunday as high pressure builds in from the
west. The high move offshore Monday with a warming trend expected
through the middle of next week.
&&
.UPDATE...
Veering low level winds have brought some scattered Atlantic
stratocumulus clouds up the the coast. Cirrus aloft is also
increasing, however at a slower rate than previous forecasts had
shown. This has necessitated a downward adjustment to forecast
lows tonight, especially across SE North Carolina away from the
beaches where mid 40s could become fairly widespread. Latest
HREF and HRRR are slower with their arrival of precipitation
Thursday, so adjustments have been made there as well to delay
the onset of PoPs by a few hours. Forcing still looks impressive
later in the day and high PoPs are certainly warranted then.
&&
.NEAR TERM /THROUGH THURSDAY/...
Latest surface analysis shows high pressure in Quebec that extends
all the way down the U.S. eastern seaboard. Meanwhile, a 1007 mb
surface low associated with the next frontal system is
situated near the Kansas/Missouri border, just south of
Nebraska. GOES-16 visible feeds with the fronts overlaid show a
nice triple point in this region.
The positioning of the high and the low has set up northeasterly
gradient winds across northeast SC and southeast NC, with a few
gusts near 20 mph recorded earlier this afternoon. Locally, skies
have remained clear over land, with a nice sprawling of altocu and
stratocu offshore.
Tonight, moisture increases aloft, and upper clouds start to stream
in from the west ahead of the front. Lows dip down into the mid-to-
upper 40s inland, lower 50s at the coast.
Frontal system should be pushing through the Ohio River Valley
Thursday morning, before reaching the local forecast area by
Thursday evening. Rain chances tick up quickly from west to east
throughout the day. Expecting about half an inch to an inch of
rainfall, which doesn`t really help the abnormally dry soils. Not
much instability to speak of, but there`s better forcing with this
system than we`ve seen in recent memory, which may bring a couple
rumbles of thunder at the coast. High temperatures will see a
gradient, ranging from the upper 50s to near 60 in the far interior
portions of the SC Pee Dee region, to the upper 60s to near 70 at
the coast.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Rainfall will be on the decrease Thursday evening with
some residual pops early. Beyond this conditions will be blustery
and mostly cloudy (especially early on) with perhaps some light rain
and or drizzle through Friday. Saturday should see mostly sunny
skies as PW`s drop dramatically. Highs will be in the lower to
middle 60s (warmer Saturday) with lows in the middle to upper 40s
Friday and lower 40s Saturday under more favorable although not ideal
radiational cooling conditions.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Outside of a natural low confidence event late in the
period (the middle of next week) the extended remains void of pops.
Temperatures in the wake of the system discussed in the short term
period are near climatology so a deliberate warm up (air mass then
advection) is noted.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
There is a high probability of VFR conditions now through at
least 12z, perhaps lasting another 4-6 hours longer near the
coast on Thursday. Upper level moisture will increase from the
west tonight and surface moisture will eventually follow from
the south on Thursday ahead of an approaching cold front. This
will lead to deteriorating ceilings and visibilities in rain.
There is a high probability of MVFR conditions developing by
afternoon with a moderate potential for IFR ceilings inland by
late in the day.
Extended Outlook...There is a moderate to high potential for
MVFR to IFR ceilings continuing through at least part of Thursday
night. Dry air arriving from the northwest should lead to VFR
Friday through Monday.
&&
.MARINE...
Through Thursday...
Small Craft Advisory continues until 4 AM EST Thursday morning,
with a combination of 6 ft seas out 20 nm offshore, and 25 kt
gusts. From there, gradient winds loosen and gradually veer
easterly and southeasterly throughout the day Thursday at 15
kts. Seas come down slightly to 3-4 ft at the coast, 4-5 20 nm
offshore.
Thursday Night through Monday...
The chances for a headline (SCA) have improved the past
day or so with the forecast for Friday and even somewhat into
Saturday. This due to a decent northwest flow in the wake of a
front. Cold air advection isn`t that impressive so the event should
be somewhat marginal in nature. For late in the weekend into early
next week the flow will weaken considerably and eventually acquire a
more return flow orientation. Significant seas will be highest early
with the headline threat (4-7 feet) followed by 2-4 feet in time.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory from 4 AM to 8 AM EST Thursday for
NCZ106-108-110.
Coastal Flood Advisory from 5 AM to 10 AM EST Thursday for
NCZ107.
SC...Coastal Flood Advisory from 4 AM to 9 AM EST Thursday for
SCZ054-056.
MARINE...Small Craft Advisory until 4 AM EST Thursday for AMZ250-252-
254-256.
&&
$$
SYNOPSIS...ILM
UPDATE...TRA
NEAR TERM...IGB
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...TRA
MARINE...SHK/IGB
Area Forecast Discussion
National Weather Service Northern Indiana
636 PM EST Wed Nov 13 2024
.KEY MESSAGES...
- Rain arrives from south to north this evening, tapering to
showers and drizzle Thursday afternoon.
- Drying out Friday thought the start of the weekend.
- Remaining mild to start next week.
&&
.DISCUSSION...
Issued at 155 PM EST Wed Nov 13 2024
Upper-level low is wrapping up over extreme western Iowa as of this
midday writing, per water vapor imagery. The surface low is lagging
behind slightly, but moisture advection is strong in the warm sector
as moisture flux buckles poleward atop a Southeast US ridge. Rain is
underway across southern Illinois lifting northeast. The
overall POP forecast remains on track. CAMs suggest a quick-ramp
up in rainfall which is plausible given a strengthening low-
level jet as we near 00z. Otherwise, in the mean time, dew
points in the 30s will need to be overcome. 12z RAP soundings
appear suspiciously fast at eroding a 30C dry slot, while HRRR
and NAM are favorably slower. Nonetheless, welcome rain is
arriving overnight and lingering into Thursday.
Forward progress of the now-stacked upper and surface lows slows
Thursday likely resulting in lingering showers or drizzle for most
of the day. The exception will be toward Lafayette where some dry
air intrusion is noted and lake enhanced rain is limited. A
subtle lake response (rain showers) is possible into Thursday
night but the cold air advection appears generally brief before
boundary- parallel flow resumes.
Drying out Friday with continued slightly above-normal warmth as
ridging resumes aloft. The ridge axis moves overhead Saturday with a
deep trough approaching the Four Corners. A baroclinic zone could be
the focus for showers Sunday night into Monday, but guidance is very
inconsistent with this. I stayed close to the existing forecast.
The Four Corners trough threatens to bring notably colder air
to the Midwest by late next week. This type of bowling-low low
(cut-off low) tends to be modeled poorly, so details locally are
sparse over one week away. The in-house blend is already
perhaps too fast with precipitation chances.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 632 PM EST Wed Nov 13 2024
Existing TAFs were generally good shape such that minor tweaks
were made in line with the current radar and satellite trends.
Rain is arriving from south to north ahead of a warm front
associated with a low over Missouri. This low will occlude
through time and move overhead Thursday resulting in a prolonged
period of showers/drizzle and IFR to even LIFR ceilings.
Confidence is high for the start of rain, but somewhat murky for
the end time given lingering drizzle. Guidance depicts subtle
ceiling improvements are possible late in the TAF period, but
guidance tends to improve ceilings too quickly in these
patterns.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Brown
AVIATION...Brown
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1047 PM EST Wed Nov 13 2024
.KEY MESSAGES...
- An approaching cold front will bring widespread wetting rains
to eastern Kentucky from tonight into Thursday evening.
- Temperatures will be near normal through Saturday, before
trending to near 10 degrees above normal for the first half of
next week.
- Rain chances return Monday night into Tuesday.
&&
.UPDATE...
Issued at 1047 PM EST WED NOV 13 2024
Updated forecast includes the mention of thunder through the
overnight for most locations. Also increased and expanded PoPs
across the forecast area through the overnight.
UPDATE Issued at 832 PM EST WED NOV 13 2024
Initial round of showers will continue to move quickly northeast
through eastern Kentucky this evening. Then, as low-level and
mid-level winds increase from the southwest overnight, widespread
rain with embedded heavier showers (and possible
lightning/thunder) should fill in over the area as warm moist
advection increases.
Minor tweaks were made to PoPs and QPF to reflect the latest
observed and model trends. The most recent temperature, wind, and
moisture readings were used for the initialization to the
forecast.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 355 PM EST WED NOV 13 2024
Late this afternoon, an upper level ridge was centered in the
vicinity of southern FL with the axis of this ridge extending into
the eastern Great Lakes to Quebec. Meanwhile an upper level trough
extended from west of Hudson Bay to the upper MS Valley to the
Arklatex vicinity with another ridge extending from Mexico north
to the Four Corner to eastern MT and into Canada while another
trough was nearing the west coast of the Conus. At the surface, a
ridge of high pressure extended from eastern Quebec to the mid
Atlantic states to GA and FL while an area of low pressure was
centered in the vicinity of Kansas City. A warm front extended
east from the low into western KY to the Cumberland Plateau of TN
to eastern TN and was nearing the southwest portion of the CWA. A
cold front meanwhile extended from the low into eastern and
southern TX with a ridge of high pressure behind it extending from
portions of the Great Basin to western and central TX. Locally,
clouds have been increasing ahead of the approaching trough and a
lead shortwave that is working into and across the Lower OH
Valley and TN Valley regions. Convection is also occurring west
and southwest of the area with showers associated with this
feature and the warm front lifting north toward central and
eastern KY. The dry airmass lingering from the departing ridging
with PW currently ranging from about 0.25 in eastern Pike County
to near 0.7 inches near Lake Cumberland and southeasterly flow
with a downslope component off of higher terrain northeast TN and
SW VA has allowed some valley locations to climb to around 70
degrees or roughly 10 degrees above normal for mid November.
Tonight and Thursday, the lead shortwave trough will work
northeast and across the area this evening while the main trough
axis/upper level low lingers to the west of eastern tonight. This
upper level low should reach the central IL vicinity near dawn on
Thursday. A plume of rather deep moisture will advect into the
region ahead of this upper level trough and the associated sfc
system. This sfc low should near Chicago around dawn on Thursday
with the warm front having lifted north of the area overnight and
the trailing cold front extending across western KY to middle TN
to the mouth of the MS vicinity at that point. PW is progged per
the 12Z HREF to climb to the 0.6 inch far eastern CWA to 1.4
inches near Lake Cumberland by midnight tonight and then peak in
the 1.1 to 1.3 inch range for the remainder of the area overnight.
Rather robust omega is expected within this moist layer ahead of
the 500 mb trough as some PVA combines with with some jet dynamics.
The deeper moisture will already have begun to shift east of
central KY by dawn on Thursday. The upper level low is progged to
track across the Lower to Middle OH Valley on Thursday with the
axis of this associated trough working east of eastern KY by
Thursday evening. PW is progged to drop to 0.6 yo 0.75 by the
afternoon and evening. However, the colder air working in from the
west will lead to an increase in mid level lapse rates to near or
possibly in excess of 7C/km from west to east late Thursday
morning into the afternoon. This combined with daytime heating per
recent RAP runs should support MLCAPE of around 100 to 300 J/kg
and MUCAPE a bit hither than that. This scenario will support
showers and isolated thunder as the sfc low passes north of the
area into OH while the cold front moves into eastern KY from
midday into the afternoon.
Thursday night, the upper low is expected to track to the southeastern
VA/northeastern NC area with rising 500 mb heights late following
the pass of a shortwave during the evening HREF to first half of
the night. The low level flow will have an upslope component with
lingering low level moisture during Thursday night resulting in
upslope/instability showers.
A wetting rain is expected across the area with most locations
likely to receive a good soaking. By 7 PM EST on Thursday the 12Z
HREF probability of at least 0.5 inches of rain is 70 to near 100
percent across the entire area. The lowest probabilities are
downwind of Black Mountain and Pine Mountain in rain shadowed
areas of northeastern Harlan County over into Letcher and southern
Perry counties. Probabilities to at least an inch by that point
per the 12Z HREF are in the 30 percent to 100 percent rang with
the lowest probabilities in the same rain shadowed areas mentioned
above with the highest probabilities near Lake Cumberland,
northeastern Pike County and areas generally north of the Mtn
Parkway.
.LONG TERM...(Friday through Wednesday)
Issued at 402 PM EST Wed Nov 13 2024
Confidence remains high in the long term forecast period through
this weekend, with the forecast guidance suite in remarkably good
agreement through Sunday night. On Friday, some residual rain
showers remain in the forecast, especially in areas along the US-23
corridor. These eastern counties will be closer to the better upper
level support, but rain chances will gradually decrease as the
parent trough departs. Northwesterly flow throughout the column
behind this feature will advect cooler and drier air into Eastern
Kentucky by Friday evening. As a result, expect cloud coverage to
slowly taper off overnight into Saturday morning. Before then, this
daytime cloud coverage and the aforementioned CAA will work together
to relegate afternoon highs on Friday to the mid 50s, with overnight
lows in the lower half of the 40s. Patchy to areal fog is possible
on Friday night and Saturday morning. Antecedent wet grounds will
aid in fog formation, and the greatest coverage will be in our river
valleys and in our southwestern counties, where the clouds will
clear first.
Most available forecast model guidance resolves an upper level ridge
building back into the Ohio River Valley this weekend, and its
associated surface high pressure system will slide through the area
at the same time. As these features move in, veering surface winds,
rising heights, and subsidence will moderate temperatures and clear
the skies. Saturday will be the sunniest day in the long term
forecast period, and strong diurnal mixing will yield our classic
ridge-valley temperature splits by Saturday night. Expect afternoon
highs near 60 degrees and overnight lows near 40 on the ridgetops.
Valleys, particularly the sheltered and seasonally shaded ones, will
cool into the mid 30s on Saturday night. Valley fog, especially in
the Cumberland basin, appears possible once again, although
increasing cloud coverage to the north and to the west could limit
coverage. Sunday will be cloudier, but warmer than Saturday as
moisture and warm air stream into the atmospheric column. Sunday`s
afternoon highs are expected to be in the mid 60s, with lows in the
mid 40s.
Confidence is beginning to increase that Monday`s forecast will
remain drier and warmer. Models still resolve a northern stream
upper level disturbance in the greater Ohio River Valley region
early next week, but now collectively position this feature north
of the river itself. As a result, the best ingredients for
precipitation will likely remain displaced from our forecast area
on Monday, although the clouds associated with this feature remain
in the forecast. This is supported by the warm and moist air
advection that models resolve out ahead of a second, southern
stream disturbance in the southern Plains. This second feature
will eject into the Midwest by mid-week in the form of a
negatively-tilted trough. While questions linger regarding the
magnitude of moisture return and the efficacy of warm air
advection out ahead of this system, it will need to be monitored
closely for convective thunderstorm potential given the dynamics
at play aloft.
Thunder has been left out of the forecast grids for
now, but likely PoPs (up to 65%) re-enter the forecast on
Tuesday. Afternoon highs could warm back up into the 70s early
next week, although ensemble member spread is markedly higher for
the end of the forecast than it is for the beginning. Therefore,
interested parties are encouraged to stay tuned to future forecast
updates as the latest model guidance comes in.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 729 PM EST WED NOV 13 2024
VFR conditions will deteriorate to MVFR and IFR conditions
through the overnight as widespread showers develop and move west
to east across eastern Kentucky. Partial cloud breaks will develop
by late morning, which will allow for additional showers and
perhaps a few thunderstorms to develop late Thursday morning into
early afternoon. Some thunder may also occur within showers
overnight and perhaps with some development near the cold front
Thursday morning. Confidence in areal extent and timing is not
high enough to include in TAFs at this point. Winds will average
from the southeast at 5 to 10 KT through about 06Z, before
trending to the south or event southwest near KSME to end the
period. LLWS can also be expected this evening until cold frontal
passage.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CMC
SHORT TERM...JP
LONG TERM...MARCUS
AVIATION...CMC
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
541 PM CST Wed Nov 13 2024
.KEY MESSAGES...
- Showers will impact the area through this evening, with isolated
thunderstorms possible west of the Mississippi River. From late
evening through the overnight hours there will be a chance of
drizzle.
- It will remain seasonably cool on Thursday with near normal
temperatures, and then a slow warm-up with above normal
temperatures will proceed Friday into early next week.
- After tonight`s rain it will be dry until Sunday with rain
chances greatest Monday and Monday Night.
&&
.SHORT TERM... (Through Friday)
Issued at 219 PM CST Wed Nov 13 2024
Rain/showers occurring across far SE MO into southern IL are being
driven by a series of weak vort maxes within southwest flow aloft
and a deep S-SW fetch of moisture transport around the periphery
of the low-level ridge and attendant with the remnants of TC
Rafael. Forecasts of IWVT show the axis of this moisture and lift
shunting to the east into the OH Valley through the remainder of
the afternoon and into the early evening in association with the
eastward movement of the Plains upper trof. Lift attendant with
the Plains upper trof and low-level convergence are currently
supporting a band of showers and isolated thunderstorms in central
MO. While there is not much instability, MUCAPE of 100-250 J/KG
has been supporting isolated thunderstorms across western MO so
far today. This rain band will move east across the CWA during the
remainder of the afternoon and into the early evening as the
forcing shifts eastward with the advancing upper trof and
attendant cold front. A low threat of thunder will continue into
early evening, after which most of the guidance has MUCAPE
diminishing markedly. In the wake of the main band of rain/showers
this evening and the departure of the deeper moisture, low-level
moisture remains. This moisture combined with some very weak
ascent supports the potential for drizzle tonight, and also into
Thursday morning across parts of IL. Present indications are the
post-frontal stratus will be widespread and locked in across the
region on Thursday. This will lead to seasonably cool temperatures
on Thursday, especially in the morning when the surface winds
remain a bit gusty. There are questions when the stratus may
actually clear and whether it could become trapped within the low-
level/surface ridge on Thursday night. The RAP and NAM low-level
RH progs maintain 90+% across much of eastern MO/western IL well
into Friday. I have trended the forecast "cloudier" on Friday, and
if the RAP/NAM are correct, the stratus could persist into
Saturday with highs both Friday and Saturday cooler than presently
forecast.
Glass
&&
.LONG TERM... (Friday Night through Next Wednesday)
Issued at 219 PM CST Wed Nov 13 2024
An upper ridge across the upper MS Valley on Friday will shift
eastward on Saturday bringing mid-upper southwest flow to the
region while an upper low/trof deepens in the vicinity of
the desert SW/northern Mexico. This will bring the start of
moderating temperatures to the area that will continue into early
next week.
The deterministic model guidance and ensembles have a strong
signal of a more active pattern by early next week as the
aforementioned SW upper low/trof moves through the southern
Rockies and ejects northeastward through the Plains and MS Valley.
There is increasing spread in solutions in the LREF cluster
analysis with regards to the position/timing of the ejecting trof.
The most probable window on impacts with this lifting trof,
associated cold front, and attendant rainfall currently appears to
be Monday into early Tuesday. The progressive nature of the trof
would limit rainfall totals and the LREF exceedance guidance
presently suggests areal average of 0.75-1.00 inches with around a
20% chance of 2+ inches locally. There is considerable
uncertainty in the forecast beyond Tuesday with large model
differences in the evolution of a deep closed low somewhere across
the central U.S.. The LREF cluster analysis shows positions of
this closed low/upper trof anywhere from the southern Rockies to
the northern Great Lakes on Wednesday.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 529 PM CST Wed Nov 13 2024
A low pressure system is currently traversing the region, and is
associated with the band of showers and isolated thunderstorms
impacting KUIN, KSUS, KSTL, and KCPS currently. Lightning within
this band has trended downward dramatically over the last hour, so
confidence remains low that thunderstorms will impact the local
terminals early this TAF period. In the wake of the showers, a
period of drizzle and reduced visibilities is expected at all
local terminals. Conditions will briefly improve as drier air
moves into the region. However, with temperatures cooling
overnight, the low-level moisture available will lead to a
lowering of ceilings again that will remain low through much of
the remainder of the period.
Elmore
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
618 PM CST Wed Nov 13 2024
.KEY MESSAGES...
- Light rain will decrease in coverage with eastward movement
this evening. Areas of patchy fog/mist linger into Thursday
morning.
- Drying out for the remainder of the work week. Temperatures warm
well into the 50s this weekend.
- Unsettled, very active upper-level pattern to bring the return
of precipitation chances across the Upper Midwest by the
middle of next week.
&&
.UPDATE...
Issued at 601 PM CST Wed Nov 13 2024
Light precip was continuing across the region, so did increase
pops a bit and used drizzle wording as the weather type. Winds
were light across the region as well. The precip should
dissipate this evening and overnight as subsidence from upper
level height rises moves across the region. This will set the
stage for light winds to continue, and this time of year that
means clouds will stick around as well given the low sun angle
of mid-November.
Looking ahead, confidence continues to grow in a large system
bringing widespread rain (possibly snow) across the region late
Monday into the middle of next week, but details on the storm
track timing and placement remain uncertain.
&&
.DISCUSSION...
Issued at 137 PM CST Wed Nov 13 2024
It`s been a tale of two different weather stories across the region
thus far today, with widespread rain across western Minnesota and
drier conditions across eastern Minnesota and western Wisconsin.
An initial band of rain developed on the nose of the nocturnal
low-level jet, in the exit region of a shortwave trough. Latest
KMPX radar imagery illustrates that the prolonged south to
north motion of rainfall has started to shift east, which is a
trend that will continue through this evening. Coverage and
intensity of rainfall will gradually wane with eastern extent,
given the departure of favorable moisture transport and
sufficient lift. However, forecast soundings indicate that low-
level moisture will linger across eastern Minnesota and western
Wisconsin. Essentially this means less in the way of steady
precipitation and more in the way of mist/patchy fog through
the evening.
Forecast soundings have trended in a pessimistic direction with
regards to sky cover tomorrow. It looks like low stratus and some
patchy fog will linger through at least mid-morning, with little
hope for breaks in the clouds. Thursday morning lows in the upper
30s are expected to only warm about 10 degrees or so into the upper
40s for highs tomorrow afternoon. Uncertainty exists with respect to
sky cover on Friday, as there are two scenarios currently in play:
Skies clear by early Friday morning, allowing for the development of
fog. Scenario two features a slower improvement to the skies, with
low stratus lingering into the daytime hours. This would limit the
potential for dense fog to develop. Latest RAP soundings have
trended in the direction of keeping the stratus around through mid-
morning Friday. Despite the challenges in the sky cover forecast, we
do have high confidence in dry weather for the end of the work week
and through the weekend.
Upper-level ridging will build across the Upper Midwest to open the
weekend, with mid-level flow/warm advection set to increase out of
the southwest. Southerly surface winds will increase by Saturday,
which will bring improvements to the sky cover and warmer
temperatures. We`ve opted to trend highs towards the NBM 90th
percentile (mid to upper 50s) given the favorable WAA regime.
Surface low pressure is progged to slide northeast out of the
Dakotas towards southern Canada Saturday into Sunday. A frontal
passage associated with the surface low is not expected to produce
much in the way of precipitation chances, however winds will kick
out of the west on Sunday. Slightly cooler, but still seasonal highs
in the upper 40s/low 50s will follow as a result.
Rain chances will return to the region early next week, as a vigorous
cutoff low pivots northeast through the central CONUS and rides
the southwesterly flow into the Upper Midwest. We currently
have medium to high confidence that widespread rain will accompany
this feature beginning Monday evening, which is reflected by
40-50% PoPs in the current forecast. Uncertainty increases
substantially beyond midday Tuesday, as there are currently a
multitude of solutions concerning the occlusion of the cutoff
and resultant phase with an upstream trough set to dig in over
the central CONUS Wednesday. Models typically struggle with the
phasing of large scale features at this distance, so it`s no
surprise that forecast guidance varies significantly from run to
run/model to model. This is amplified by the amount of moving
pieces in the upper air pattern spanning from the Pacific
Northwest to the tropics/SE CONUS next week. Where, when, and
how strong phasing of the upper air features and eventual
occlusion of the surface system will make a big difference in
the weather experienced locally. Fans of winter weather may be
quick to latch onto a solution that produces bullish snowfall
amounts across the region during the second half of next week.
It`s simply too soon to have confidence in any one outcome. For
now, get ready to enjoy a nice November weekend by MSP standards
and stay tuned for more information regarding active weather
next week. What seems more certain at this time is the arrival
of colder air by the end of next week. (It`s about time!)
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 601 PM CST Wed Nov 13 2024
Conditions expected to lower overnight to IFR/LIFR as low clouds
and fog become more widespread across the region. Areas of light
rain and drizzle will gradually fade from west to east, and
should dissipate by midnight. Winds will be light, but should
generally take on a northwest direction. On Thursday, the light
winds will allow the clouds to hang around most of the day, but
should have some gradually improvement to MVFR by Thursday
afternoon.
KMSP...Light rain and drizzle will continue for the next few
hours. Expect ceilings to lower overnight, with IFR conditions
into Thursday morning. Winds will be light, but should become
northwest by morning. Ceilings will gradually lift on Thursday,
but could be slower to improve than the current TAF indicates.
/OUTLOOK FOR KMSP/
FRI...VFR. Wind SE 5-10kts.
SAT...VFR. Wind SE 15G25-30kts.
SUN...VFR. Wind W 15G25kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...JRB
DISCUSSION...Strus
AVIATION...JRB
Area Forecast Discussion
National Weather Service Marquette MI
620 PM EST Wed Nov 13 2024
.KEY MESSAGES...
- Lingering light showers taper off late Thursday from a system
sliding to our south.
- Another period of quiet weather will follow Thursday`s system
until the next chance of light rain arrives Sunday.
- Plenty of model uncertainty regarding potential storm system
developing over the Great Lakes for mid-late next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 240 PM EST Wed Nov 13 2024
Water vapor imagery and RAP analysis show a shortwave trof over the
Plains. Within the trof, a well-defined wave is over eastern
KS/Nebraska. At the sfc, a trof extends from se Manitoba southward
to TX. The aforementioned shortwave is supporting a low pres
developing along the trof over far se Nebraska/far ne KS. Radar
mosaic show shra along and ahead of the trof. A second area of shra
is surging n across the Lwr Ohio Valley in response to strong 850-
700mb moisture transport on the leading edge of northward advancing
precipitable water of 1-1.5 inches. Closer to home, bkn-ovc lake
stratocu expanded across much of central Upper MI this morning under
s to se low-level winds off of Lake MI. That stratocu has scattered
out in most areas, but bkn clouds are still noted over s central
Upper MI. Much higher up, ci cloudiness is spreading into Upper MI
from the s and sw. Temps are currently in the mid and upper 40s F.
Where there has been more sun, resulting in deeper mixing, southerly
winds have been gusting to 25-30mph at times.
Shortwave over the Plains will shift e tonight with the associated
organizing low pres lifting toward ne Illinois. In response, the
aforementioned surge of moisture now into the Lwr Ohio Valley will
continue to surge n tonight, though the northern end will weaken in
comparison to farther sse. Nonetheless, it will support rain
spreading into roughly the eastern 2/3rds of Upper MI in the 06z-12z
timeframe. Rain intensity will be on the light side for the most
part. By 12z, rain amounts should range from 0.2-0.4 inches from
Menominee toward Escanaba with amounts decreasing sharply to the nw,
n and ne of there.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 229 PM EST Wed Nov 13 2024
Models indicate that the progressive pattern over the CONUS through
this weekend will become much more amplified next week as anomalous
5h ridging over western North America forces an amplified mid-upper
level trough into the Central CONUS by middle to late next week.
This pattern transition will bring about the potential for an
impactful storm system to develop somewhere over the Great Lakes for
middle to late next week. However, ensemble spread in member
solutions is kind of all over the place which is resulting is poor
forecast confidence on any particular model solution at this time.
Light rain showers continue mainly across the eastern UP Thursday
morning into the early afternoon, with a surface low tracking
through the Lower Midwest and the midlevel trough pivoting over the
Great Lakes extending weak forcing into the U.P. Greatest shower
coverage looks to be over the central and eastern U.P. where
ensemble probability fields indicate a 70-100% chance of 0.1 inch or
more of rainfall on Thursday. Isolated shower coverage over the west
will result in rain amounts of trace to no more than a couple of
hundredths. Expect max temps generally in the mid to upper 40s. Weak
cyclonic flow could result in some isolated rain showers lingering
into Thursday evening, mainly over the east half with min temps
expected in the 30s.
Models indicate ridging will amplify into the Great Lakes region
Friday into the early part of the weekend in response to a trough
amplifying over the western CONUS. This should support dry weather
Friday into Saturday along with a warming trend. Expect above normal
highs in the upper 40s to lower 50s both days with lows Friday night
ranging from the upper 20s to lower 30s over the interior to the
mid 30s near the Great Lakes shores.
Forecast attention then turns upstream to the development of a low
over the lee of the Colorado Rockies Friday night which models and
ensembles indicate will deepen and track northeast through the
Dakotas on Saturday and then into southern Manitoba and northern
Ontario Saturday night into Sunday. As this ~996mb sfc low tracks
east across northern Ontario it will push a cold front across Upper
Mi late Saturday night into Sunday. Breezy southwest winds ahead of
the front Saturday night into Sunday morning will become west and
gusty behind the front Sunday afternoon and evening. Despite a lack
of good cold advection behind the front (850 mb temps only drop to
around -2C) the strength of the low and tightening of the gradient
on its southern periphery will still lead to widespread gusty west
winds of 20-30 mph with wind gusts perhaps approaching advisory
criteria of 40-45 mph across the Keweenaw Peninsula (40% chance per
EPS guidance). Weak forcing and limited moisture along the front
with PWATs only around half an inch should limit rain shower
coverage late Sat night into Sunday to isolated to scattered at
best, greatest east half.
Ridging builds back in late Sun night into Monday with more dry
weather and above normal temps with lows Sunday night ranging from
the upper 20s to lower 30s over the interior to the mid 30s near the
Great Lakes shores and highs Monday generally in the upper 40s lower
50s.
As the pattern begins to amplify early next week over the CONUS a
shortwave/closed low over the CA Baja region will get ejected ne
through the Plains States on Monday. After Monday, models struggle
on how this initial closed low/shortwave energy will interact with
the broader mid-upper level trough digging into the central CONUS by
midweek. Once models sort these details out hopefully forecast
confidence will increase in the coming days on determining the
evolution of the developing storm system over the Midwest and Great
Lakes region and its subsequent impacts for the middle to latter
part of next week. For now at least, it looks like increasing
chances for rain for our area in the Tuesday-Wednesday time frame as
models suggest, at least initially, a more westward track with the
developing storm system through the Central Plains into the mid-
upper Mississippi Valley region. Ptype and pcpn coverage then
becomes more uncertain across the area later next week as models
continue to struggle with details on the storm`s evolution.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 620 PM EST Wed Nov 13 2024
Surface low will lift into the Great Lakes in this TAF period,
resulting in precip spreading into Upper Michigan this morning,
winds shifting to the northeast, and lowering ceilings. KSAW will
experience impacts first, likely falling to MVFR and then quickly to
IFR soon after later this morning as the rain and deeper moisture
moves into the region. KCMX should begin deteriorating a little
later, but still dip into MVFR this morning and then to IFR in the
afternoon. KIWD will likely be last to see MVFR ceilings develop,
likely by late in the period under northerly flow. Winds at all
sites should be light while they shift around to the northeast and
east.
&&
.MARINE...
Issued at 229 PM EST Wed Nov 13 2024
Ahead of the frontal system over the Plains, southerly winds remain
elevated this afternoon with gusts to around 20-30kts, highest east
half. Winds fall back below 20 kts later tonight and gradually back
more easterly. Winds will remain under 20 kt several days before
increasing to southerly winds up to 25 knots late Saturday into
early Sunday, and then to southwest-west winds to 30 kts behind a
cold front Sunday afternoon and evening. Ensemble probability
suggests a 30-50% of westerly gales over west half portions of the
lake Sunday afternoon and evening.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...LC
AVIATION...JTP
MARINE...LC
Area Forecast Discussion
National Weather Service Portland OR
220 PM PST Wed Nov 13 2024
.SYNOPSIS...Strong south winds continue to decrease in strength
through the afternoon, however conditions will remain quite breezy,
especially near the coast. Currently transitioning to convective
showers and thunderstorms through the evening. Remaining cool and
showery Thursday, albeit less windy. Trending colder and drier late
Friday into Saturday morning before conditions become wet again
Saturday night into Sunday. Trending drier again early next week as
offshore flow develops.
&&
.SHORT TERM...Now through Thursday Night...Active post-frontal
conditions throughout the region, with scattered showers and
thunderstorms, particularly at the coast. Winds at the coast have
decreased from this morning, with current maximum gusts around 40
mph. Inland, elevated southerly gusts up to 30 mph still remain
possible. Some tree damage and isolated power outages are
possible.
Any thunderstorm that does form Wednesday morning or afternoon will
have the potential to produce heavy downpours and brief erratic wind
gusts up to 45-55 mph. Cannot rule out a waterspout or two over the
coastal waters, which would have the potential to cause highly
localized wind damage if moving inland towards a coastal community.
Small hail is also possible with any thunderstorm that does develop.
Winds continue to decrease going into the evening, with showers and
storms decreasing during that time as well.
Given many storm drains are currently clogged up with leaves, hourly
rain rates around 0.2 in/hr or higher will be enough to cause some
issues in flood prone areas. Higher rain rates are tied to
thunderstorms passing directly overhead, so this should be fairly
limited due to the isolated nature of these showers. While rain rates
will be much lower than this most of the day, all it takes is one
quick downpour for impacts to occur. If you encounter a flooded road
when driving, be sure to turn around if possible as it is impossible
to tell exactly how deep the water may be. Hydroplaning will also be
a risk for motorists.
Thursday sees continued chances of storms, particularly at the coast,
but these will be much more isolated and weaker due to much weaker
CAPE values under 100 J/kg. Showers continue throughout Thursday, but
with lower accumulations. Probability of rain accumulation over 0.50"
between 4am Thu-4am Fri are only around 20% in the Willamette Valley.
Elevated areas (Coast Range, Cascade foothills) will see values
closer to 1" throughout that period.
/JLiu
.LONG TERM...Friday through next Wednesday...The long term forecast
is highlighted by a cool and wet weather pattern typical of
mid-November, however it will not be wet all day every day.
WPC`s cluster analysis for 500 mb heights and anomalies suggests
excellent agreement between the GEFS/EPS/CMC, showing an upper level
trough over the western CONUS on Friday shifting near the Desert
Southwest over the weekend. The grand ensemble mean shows northerly
flow will dominate western WA/OR Friday into Saturday, which will
support a brief period of drier weather late Friday through Friday
night with clearing skies. Given the calm winds expected during that
time, conditions will be favorable for radiational cooling and near
freezing to below freezing temperatures. The NBM continues to show a
60% chance for overnight lows of 32F or colder for most lowland
locations, aside from the immediate coast, Columbia River Gorge and
urban cores such as Portland, Vancouver and Salem where temps are
more likely to bottom out in the mid to upper 30s. Locations that do
see below freezing temps could see frost and a few slick spots
Saturday morning on surfaces that remain wet leading into Friday
night.
This cooler and drier pattern will quickly come to an end as the
flow becomes zonal on Sunday with increasing onshore flow. At the
same time, models continue to show a Pacific frontal system moving
inland, bringing more significant rain amounts late in the weekend.
That being said, expecting minimal impacts with this system as winds
do not look overly significant and ensemble guidance for QPF suggest
rain amounts will not be high enough for hydro concerns unless the
wettest ensemble members verify. It appears the NBM 90th percentile
would need to verify for some hydro concerns to materialize.
Weak ridging attempts to build in once again early next week but
looks short lived. Models and their ensembles are still showing a
transition to offshore flow Tuesday into Wednesday, albeit weaker
than previous model runs. Nevertheless, the forecast for the middle
part of next week is still trending towards cool conditions with
breezy east winds in the Columbia River Gorge and eastern Portland
metro. The forecast is trending drier during that time as well,
however precipitation cannot be ruled out completely yet. NBM PoPs
generally range between 15-35% Tuesday into Wednesday.-TK
&&
.AVIATION...A mix of VFR and MVFR across the area in post cold
frontal air mass. Thunderstorms have developed this afternoon over
the waters, and some have moved ashore. Radar earlier indicated a
few storms had rotation over the waters for possible waterspouts.
Conditions remain favorable for thunderstorms and possible
waterspouts through tonight. 12Z Wed HREF 4-hr thunderstorm
guidance shows a highest chances 60-80% at the coast from about
22Z Wed through 03Z Thu, then lower chances overnight. Thunderstorm
chances are about 20% for inland areas through tonight. Latest HRRR
shows some robust cells moving in over the valley roughly 00-03Z Thu
so may need to add a chance for TSRA at TAF sites. Overall, flight
conditions will continue to be a mix of VFR and MVFR with lower
conditions possible with stronger showers or thunderstorms.
Gusty south to southwest wind continue tonight with gusts 20-30
kt, strongest at the coast.
PDX APPROACHES...Showers and a mix of VFR and MVFR through
tonight, but MVFR should be rather brief as heavier showers pass
through. There is about a 20% chance for thunderstorms through
tonight. /mh
&&
.MARINE...Gusty south to southwest wind continue tonight in the
post cold frontal air mass. Showers with a chance of thunderstorms
and possibility of a waterspout continue through tonight. Wind
gusts should remain below gale force, but thunderstorms can
produce brief gales as they move through. Winds become westerly
late tonight as a trough moves across the waters. Winds ease
through the day Thursday as high pressure builds offshore.
A mid period westerly swell moves into the coastal waters at 14
to 17 feet around 13 seconds tonight. Once this swell passes the
wave state finally calms for the second half of Friday into
Saturday with significant wave heights dipping below 10 feet.
However we`ll need to watch another weather disturbance expected
to arrive late Sunday into Monday bringing another round of active
weather. /mh
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Hazardous Seas Warning until 7 PM PST Thursday for PZZ210-
251>253-271>273.
&&
$$
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Area Forecast Discussion
National Weather Service Tallahassee FL
1000 PM EST Wed Nov 13 2024
...New UPDATE, MARINE...
.UPDATE...
Issued at 952 PM EST Wed Nov 13 2024
The main changes to tonight`s forecast were tweaking rain chances
to account for a convection moving east from the MS Valley in
association with an approaching cold front. There is some
instability to work with to warrant the continued mention of
thunder. The latest hi-res guidance shows an arrival of this
convection at the FL Panhandle & SE AL by 12Z.
The environment is favorably sheared for organized storms, but
instability is the limiting factor. The best potential for robust
activity is around the Emerald Coast where CAPE is greatest. The
0Z HRRR shows a linear semi-organized storm mode trailing
southward offshore by around rise. It would not be surprising to
see rotating showers or thunderstorms accompanied by strong gusts.
Speaking of, St George Island has been frequently gusting in
excess of 30 mph this evening, so raised winds/gusts overnight
along coastal Franklin County.
&&
.NEAR TERM...
(Through Thursday)
Issued at 350 PM EST Wed Nov 13 2024
A cold front will approach the region on Thursday and bring rain to
much of our western zones of the forecast area with lower rain
chances across southern Georgia and the Big Bend. The front that
moved through the forecast area this morning is expected to become a
stationary/warm front later tonight as the first of two shortwaves
moves through. Clouds will be steadily increasing late tonight
across our western zones and light rain will likely develop as the
shortwave begins to interact with this feature. Additionally, a weak
area of low pressure associated with the remnants of Rafael will be
lifting north Thursday morning. The combination of the increasing
moisture and the initial shortwave should lead to widespread showers
across the Panhandle and southeast Alabama and possibly a chance for
a few thunderstorms.
The second of two shortwaves moves through later on Thursday
morning/afternoon and will eventually catch up to the first
shortwave later in the day. Additional showers will accompany the
front before things clear quickly from west to east beginning in the
early parts of Thursday afternoon. Overall, flooding/severe concerns
are quite low with this frontal passage, but a non-zero risk for
severe weather is possible across the region given weak shear in
place and some low increase in instability during the morning. Any
severe risk is likely to be confined to our Florida counties in the
better instability across the Florida Panhandle.
&&
.SHORT TERM...
(Thursday night through Friday night)
Issued at 350 PM EST Wed Nov 13 2024
A cold front will be in the process of pushing east through the
region Thursday night. Behind it is a fresh area of high pressure
with highs easing back into the lower to middle 70s and overnight
lows in the upper 40s to lower 50s. While that may seem cold, and it
is compared to what we`ve experienced the past couple of weeks, it`s
actually near normal for mid-November.
&&
.LONG TERM...
(Saturday through Tuesday)
Issued at 350 PM EST Wed Nov 13 2024
A continuation of near normal temperatures is in the offering this
weekend before moderating early next week. An H5 ridge develops
overhead Saturday and Sunday, keeping rain chances away from the
region. Meanwhile, a longwave trough moving into the western half of
the country will begin to cut-off across northern Mexico Saturday
into Sunday. This trough will lift out of the Desert Southwest and
head for the Great Lakes, bringing a cold front along with it. There
appears to be enough moisture return off the Gulf of Mexico to
introduce low, less than 20%, rain chances next Tuesday afternoon.
Looking at the tropics, Potential Tropical Cyclone #19 has formed in
the Caribbean Sea. It is forecast to near Honduras over the weekend
and slow to a crawl. From there, it is forecast to head for
Belize/Mexico. There is a high amount of uncertainty in the
eventual track of this system, which will initially be influenced
by ridging to the northeast, then by a trough digging into the
Central US by the middle of next week. It`s too early to determine
whether there will be any impacts to the Tri-State region, so
please continue to monitor this system.
&&
.AVIATION...
(00Z TAFS)
Issued at 645 PM EST Wed Nov 13 2024
Mostly VFR prevails for at least the first half of tonight until
a frontal band of convection moves in from the west. Latest
guidance shows an arrival at ECP/DHN as soon as 10Z with
accompanying MVFR conds. South to SE winds are fcst ahead/along
the front. There is enough of a signal to mention thunder via a
PROB30 group at ECP between 12-18Z. Convective impacts encroach on
ABY/TLH by about 17Z. Expect a sharp wind shift out of the west
to SW near 10 kts in the front`s wake despite improving flt conds.
&&
.MARINE...
Issued at 952 PM EST Wed Nov 13 2024
The West Tampa Buoy (42036) was reporting a sustained east wind
of 21 kts, seas around 4 ft, and a dominant period of 5 seconds.
The St George Island Bridge has also frequently been gusting in
excess of 25 kts this evening. A semi-organized line of convection
ahead of an approaching front enters the western waters during
the pre-dawn hrs and may pose a threat for strong winds, frequent
lightning, and waterspouts, especially off the Emerald Coast.
From CWF Synopsis...Small Craft Advisories remain in effect for
much of the northeastern Gulf of Mexico as strong high pressure
over the Northeast tightens the pressure gradient and brings an
increase to fresh and strong easterly breezes through Thursday
morning. A cold front will pass across the waters on Thursday and
Thursday night, preceded by southeast breezes followed by a surge
of fresh northerly breezes. Winds will clock around from northerly
to easterly over the weekend, as high pressure moves by to the
north. &&
.FIRE WEATHER...
Issued at 350 PM EST Wed Nov 13 2024
Cold front moves through the region Thursday bringing a good chance
of wetting rains to the Florida Panhandle and southeastern portions
of Alabama. Chances for wetting rains decrease as one goes further
east into southern GA and the Florida Big Bend. The moist conditions
should keep fire concerns low on Thursday. Drier conditions move in
for Friday and the weekend but fire concerns should remain on the
low side.
&&
.HYDROLOGY...
Issued at 350 PM EST Wed Nov 13 2024
A few showers and thunderstorms are expected tonight into Thursday.
Most model guidance has the bulk of the rain falling west of our
area in the Florida Panhandle. A cold front pushes through Thursday
and will lead to drier conditions this weekend into next week. There
are no flooding concerns over the next week.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 68 77 55 71 / 20 30 20 0
Panama City 70 80 54 72 / 60 50 10 0
Dothan 65 77 49 70 / 40 40 10 0
Albany 64 76 51 70 / 30 30 10 0
Valdosta 65 80 54 71 / 10 30 30 0
Cross City 66 82 58 74 / 0 30 30 0
Apalachicola 72 79 56 72 / 20 30 10 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Friday morning for FLZ108-112-114-
115.
GA...None.
AL...None.
GM...Small Craft Advisory until 10 AM EST /9 AM CST/ Thursday for
GMZ750-752-755-770-772-775.
&&
$$
UPDATE...Gonzalez
NEAR TERM...Dobbs
SHORT TERM...Reese
LONG TERM....Reese
AVIATION...Gonzalez
MARINE...Reese/Gonzalez
FIRE WEATHER...Dobbs
HYDROLOGY...Reese