Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/18
Area Forecast Discussion
National Weather Service La Crosse WI
933 PM CDT Fri Oct 5 2018
.UPDATE...
Issued at 933 PM CDT Fri Oct 5 2018
Forecast evolving about as expected earlier, though the heaviest
rain axis appears it may end up a couple tiers of counties farther
south. Regional radars showing an elongated axis of showers and
storms running northeast from southwest Nebraska into northern
Iowa, in the vicinity of an elevated warm front and within a zone
of persistent and modestly strong low level moisture transport.
Per near term guidance and radar trends, doesn`t appear that axis
will move much overnight, with the attendant heavy rain risk
following a trajectory that may just clip our far southern
counties (Grant/Clayton), but in all likelihood will end up just
south of our local area.
In concert with surrounding offices, have trimmed the northern
fringes of the current Flash Flood Watch where the heavy rain
threat is over for tonight, but will leave Grant/Clayton as a
"buffer" and see where later radar trends take us. May ultimately
be able to cancel those counties too a bit later tonight. No
complaints from us as those areas just can`t take any more water
after recent flooding.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 345 PM CDT Fri Oct 5 2018
At 3 PM, south of the surface warm front across Missouri and
Kansas temperatures have warmed into the mid and upper 80s with
dew points near 70. 925 and 850 mb southerly winds ahead of a
short wave trough over the Central Plains is lifting this
instability aloft. This has resulted in elevated (850-700 mb)
showers and scattered thunderstorms developing across Iowa. The
RAP continues to show that the most unstable instability will
gradually build northward late this afternoon and evening. It
climbs to around 750 J/kg this evening and then much of the
instability settles south of the area during the overnight. The
strongest 850 mb moisture transport will be during the evening and
then it veers away from the area during the overnight. This is
likely the reason why many of the CAMs are showing that the
greatest coverage in showers and storms this evening and then
there is a shift south of the area during the overnight. The
latest HRRR seems to be picking up on this evolution the best.
One change from yesterday is that the highest precipitable water
values and warm cloud layer have shifted southeast of the area.
With this said, there is still precipitable water values around
1.5 inches and warm cloud layer depths around 3.5 km. This means
that if there is going to be any flash flooding tonight it will
likely have to occur from the rates. At this time, thinking the
highest chances of flash flooding in our area will be likely in
Clayton County in northeast Iowa and Grant County in southwest
Wisconsin. However, did not have a high enough confidence to
remove any counties from the Flash Flood Watch.
.LONG TERM...(Saturday night through Friday)
Issued at 345 PM CDT Fri Oct 5 2018
On Sunday night and Monday, a warm front across southern Iowa
will move northward into the region. As this occur, instability
and moisture will spread northward into the region. Precipitable
water values climb into the 1.5 to 1.75 inch range and warm cloud
depths are between 3.5 and 4 km. This will make any showers or
storms efficient rain producers. One of the main questions is how
far north will this front end up getting. Both the GFS and GEM
move this warm front north of the area by Monday evening.
Meanwhile, the ECMWF has its warm front stalling near Interstate
90 through Tuesday before lifting north of the area. This warm
front position will have an impact on where there may be potential
flooding. In addition, there is some concern that there may be
enough shear at times for maybe some isolated severe storms from
time to time.
On Wednesday, a cold front will move east through the region. The
timing of this front will greatly impact our severe weather
potential. At this time, the ECMWF is by far the slowest and most
dynamic with this system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 644 PM CDT Fri Oct 5 2018
Widespread lower stratus remains in place this evening, with
ceilings mainly MVFR but expected to gradually lower to IFR for
most areas as a weak cold front approaches. Could see a few
showers for LSE and maybe RST too ahead of that front through 06Z,
but nothing widespread expected. Winds ahead of the front will
remain light as well (under 5 knots for most spots), shifting
northwesterly and increasing to 10-15 knots later tonight into
Saturday. As that occurs, there should be a gradual lifting of
ceilings back to MVFR levels, and potentially even VFR, though
confidence in how much cloud cover will eventually erode after
18Z Saturday remains low.
&&
.HYDROLOGY...
Issued at 345 PM CDT Fri Oct 5 2018
There is going to be extended time period where flooding and flash
flooding will be of great concern.
The first time period of concern will be from tonight into
Saturday morning for Fayette and Clayton counties in northeast
Iowa and Crawford, Grant, and Richland counties in southwest
Wisconsin. These counties will likely see around 1 inch with
local totals up to 2 inches. With the soils already saturated,
this rain will quickly runoff into area rivers and streams which
are already running high. With the many of the CAMs shifting
south, thinking the highest concern in our area will be in Clayton
and Grant counties. Due to this concern, a Flash Flood Watch
remains in effect for the aforementioned counties.
The next time period of concern will be from Sunday night into
Wednesday. During this time period, a slow moving cold front will
be moving east through the region. With a series of low pressure
areas moving along this front, the showers and storms will train
repeatedly over the same areas. With precipitable water values
running between 1.5 and 2 inches and warm cloud layer depths of
3.5 to 4 km, the showers and storms will be rather efficient rain
producers. This could result in widespread flooding depending on
how this all plays out.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Flash Flood Watch through Saturday afternoon for WIZ061.
MN...None.
IA...Flash Flood Watch through Saturday afternoon for IAZ030.
&&
$$
UPDATE...Lawrence
SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Lawrence
HYDROLOGY...Boyne
Area Forecast Discussion
National Weather Service Burlington VT
1016 PM EDT Fri Oct 5 2018
.SYNOPSIS...
High pressure will bridge across and east of the area overnight
with clear to partly cloudy skies, cool temperatures and areas
of frost. A frontal system will push into the region by Saturday
afternoon into Saturday night with periods of showers,
especially across northern counties. Temperatures return to near
seasonable levels by Sunday, with a trend toward much warmer
values by next week as strong Atlantic high pressure builds
across the Mid Atlantic into the northeast.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 1016 PM EDT Friday...Not much change with the latest
update as cloud cover still is thoroughly entrenched across the
region. Model data continues to suggest this cloud cover will
continue until early Saturday morning before a brief thinning of
the clouds is expected. The temperature/frost forecast still
remains tricky but everything should remain on track as long as
the cloud cover continues. Newest HRRR and RAP are finally
picking up on the moisture which gives added confidence in the
warmer temperatures overnight from the last update.
Previous Discussion...Quiet weather continues tonight as
high pressure bridges across the region. A broad increase in
filtered high cloudiness is expected over time tonight as
southwesterly return flow begins aloft despite near calm winds
at the surface. Temperatures will run similar to last night,
bottoming out from the upper 20s to mid 30s in the northern
mountains, and from the mid 30s to around 40 in the broader
valleys and southern VT. As such, our current frost/freeze
headlines for tonight remain in place with this package. Of
note, the growing season has ended for the Adirondacks and the
Northeast Kingdom of Vermont so no additional frost/freeze
headlines will be issued for these areas for the remainder of
the year.
By Saturday models remain on board showing the surface high
moving eastward, allowing a pronounced warm front to surge
northeast into the area. The idea of increasing clouds and
showers still appears reasonable with highest chances across the
north where better isentropic lift and low to mid level
frontogenetical forcing exist. Despite this general agreement
there`s quite the discrepancy in regard to temperatures tomorrow
with this morning`s NAM showing the boundary getting hung up
along the western slopes of the Adirondacks, north of which
temperatures could stay quite cool. Meanwhile, the GFS is
considerably warmer and is less pronounced with the baroclinic
zone across the front. After perusal of data I`ve leaned toward
a blended solution comprising several bias- corrected solutions
which lean somewhat more heavily toward the NAM- based output.
This would support highs mainly from 60 to 65 south of the
front, and in the mid to upper 50s north of the front across the
SLV. If the raw NAM output were to verify areas along the St.
Lawrence River may only hold in the lower 50s tomorrow under a
raw northeasterly flow. Time will tell. In regard to the shower
threat it appears given frontal timing and juxtaposition of
better dynamical fields our northern/northwestern counties
should have the highest threat, becoming most focused from the
afternoon hours onward into early evening. Further south, points
from Ticonderoga through Montpelier and points southward to
likely stay dry for the majority of the day under thickening
clouds.
By tomorrow night, weak low pressure rides along the near
stationary boundary draped across our northern counties and/or
southern QE/ON. As this feature passes, the front will sag
southward back through the area, clearing southward toward dawn
on Sunday. Steadier showers and/or periods of light rain will be
most focused across the north during the evening and first half
of the night before settling gradually southward over time
after midnight. 12-18 hour blended QPF output supports basin
average totals ranging from 0.25 to 0.50 inches across the far
north, 0.15 to 0.25 across the Adirondacks into central VT, and
less than 0.15 across southern counties by 12Z Sunday. Low
temperatures close to national blended output - mainly upper 40s
lower 50s north and lower to mid 50s south.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 335 PM EDT Friday...Will have some lingering light rain
showers over the area Sunday as frontal boundary is slow to drop
South of our area. Model runs have consistently slowed down
this feature`s exit the past few runs. Showers should finally
end Sunday night as surface high ridges into the area out of
Canada. On Sunday the temperatures will be coolest North of the
boundary with upper 50s to around 60 while south of the boundary
temperatures will edge into the upper 60s and around 70. Skies
remain pretty cloudy Sunday night despite high pressure
beginning to ridge into the area, temperatures will mainly be in
the 40s to around 50.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 335 PM EDT Friday...Upper ridge will be centered off the
Delmarva coast on Monday and westerly upper level flow will
develop across our area. The surface high over Canada will begin
to shift eastward and our region will be relatively dry on
Monday. From Tuesday onward the weather pattern becomes more
active with a large scale low pressure system and the remnants
of a tropical system both keeping active weather across much of
the Eastern Conus. On Tuesday a weaker low pressure system
passes well North of our area, but brings a chance for some
showers. Our region should get into the warm sector on Wednesday
bringing more chances for some showers. Then on Thursday large
low pressure system approaches from the Great Lakes bringing
more precipitation. May have another ridge of high pressure
building into the North Country on Friday. Overall warm
temperatures and active weather is expected over the next week.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...VFR conditions and light winds will
continue through the evening and overnight hours before an MVFR
deck begins to work into the region from the southwest after
12Z Saturday. Ceilings will continue to lower throughout the day
on Saturday with IFR conditions possible by 00Z Sunday across
KMSS while the remainder of TAF sites will reside in the 1500 to
2000 ft range. Winds should generally be less than 10 knots
from the south but a few gusts in the 15 to 18 kt range will be
possible at KBTV and KRUT during the late morning and early
afternoon hours. Will need to watch KSLK as a nice low level jet
moves overhead tomorrow afternoon and if winds go slack, there
could be some low level wind shear of 35 knots at 2000 ft.
Outlook...
Saturday Night: Mainly IFR, with areas MVFR possible. Likely RA,
Chance SHRA.
Sunday: Mainly MVFR, with areas IFR possible. Chance SHRA.
Sunday Night: Mainly MVFR, with areas VFR possible. Chance SHRA.
Columbus Day: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.
Monday Night: Mainly MVFR, with local VFR possible. Chance SHRA.
Tuesday: Mainly MVFR, with local VFR possible. Chance SHRA.
Tuesday Night: Mainly MVFR, with areas VFR possible. Chance SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Frost Advisory until 8 AM EDT Saturday for VTZ002-005-009-010-
012-016>018.
Freeze Warning until 8 AM EDT Saturday for VTZ006-008.
NY...Frost Advisory until 8 AM EDT Saturday for NYZ028-035.
&&
$$
SYNOPSIS...JMG
NEAR TERM...Clay/JMG
SHORT TERM...Neiles
LONG TERM...Neiles
AVIATION...Clay
Area Forecast Discussion
National Weather Service Des Moines IA
904 PM CDT Fri Oct 5 2018
.UPDATE...
Issued at 903 PM CDT Fri Oct 5 2018
Updated FF.A to drop Bremer County. Models still focusing more
precipitation over the south...though may still brush US 20.
Southeast counties may see more of the rainfall tonight - but
antecedent conditions there should allow for more capacity. Will
continue to monitor. /rev
&&
.DISCUSSION.../Tonight through Friday/
Issued at 411 PM CDT Fri Oct 5 2018
Scattered showers with a few rumbles of thunder south of Highway 20
with scattered storms south of I-80 are moving northeastward at mid-
afternoon. GOES-16 shows plenty of clouds over the state with a few
holes in the clouds, but latest MUCAPE has generally 500 J/kg or
less over Iowa, but there is good deep layer shear. Could see some
small hail or gusty winds over the south before sunset this
evening. Tonight, things transition to heavy rainfall concerns as
good Q-vector convergence passes over much of the state. While
the surface boundary will stay south of the state, the 850mb
boundary will be over southern Iowa, which is denoted by the line
of broken convection back into northeast Kansas/southeast Nebraska
into west central Illinois. Precipitable water values will be
between 1.5 to 1.75 inches along and south of this boundary, which
is well above normal. 12z NAEFS percentiles for specific humidity
are at the maximum percentile and PW in the 99th percentile.
Flash flood guidance continues to indicate values of 1.5 to 2
inches in an hour with 2.5 to 3.5 inches in 6 hours to be of
concern. Consensus for models indicate a broad 1 to 2 inches south
of a Tama County to Adams County line. Certainly could see
isolated amounts greater than 2 inches and closer to 3 inches per
some models in the aforementioned area. 17z and 18z HRRR
runs are a bit concerning with 4 plus inches in our far
southeast; however, this is just one model amongst many. In
addition, 12z HREF Probability Matched Mean (PMM) and Localized
Probability Matched Mean (LPMM) show a thin corridor of 2 to 3
inches from Taylor County up towards Warren County and the 12z
NSSL convective allowing models (CAMs) such as the 12z WRF- NSSL
3km and and 0z FV3-NSSL have 2 to around 3 inches south of the
HREF heavier band. Overall, confidence is low in the placement of
this heavier band. For now, will extend a few counties on the
southwest side of the watch, though possible extension farther
south is possible, especially if near term trends and additional
CAMs start to trend towards the 17z/18z HRRR.
By 12z Saturday, most of the showers and storms will be over the
southeastern half of the state. This area will have the chance for
showers and storms as Q-vector convergence lingers throughout the
day with the best chances in the far south and southeast. Another
shortwave trough will bring a surge of higher precipitable water
values over 1.5 inches later Saturday night into Sunday morning
over the southeast half of the state. The surface boundary will
begin to lift northward toward the state on Sunday and move north
of the state by late Monday as the trough over the western US
amplifies. With Iowa in the warm sector by later Monday and with
good flow of moisture from the Gulf of Mexico between the high
pressure over the southeast US and trough over the western US, PWs
over the state will be a remarkable 1.5 to 1.75 inches for
October. From late Sunday into the middle part of next week is the
greatest concern for flash flooding with the high PW values,
skinny CAPE profile, and deep warm cloud depths around
3500m. This will also be the beginning of river flooding with
repeated opportunities for heavy rainfall as the general idea from
models show low pressure moving very slowly from the southern
Rockies into Minnesota. GFS would yield the "low" amount of
rainfall with 2 inches storm total as it moves quicker from now
through late Wednesday with the ECMWF still advertising widespread
4 to 6 inches across much of central Iowa. Rain should come to an
end by late Wednesday or Thursday morning depending on the model
solution. The GFS and CMC are about 6 to 12 hours faster than the
ECMWF so there will be some adjustments to the end of the rainfall
as we get into next week.
Thursday will bring a much needed dry day as high pressure crosses
the northern Plains. On the horizon for late next week or next
weekend will be a northern stream shortwave trough over the
western US that will be moving eastward on Friday. GFS is much
farther north with the ECMWF digging into southern California so
there are obvious differences as there typically are at this time
horizon. This difference will have implications on how the
remnants of Hurricane Sergio from the eastern Pacific are brought
up through the southwest US and into the central US. Regardless of
solution, GFS, CMC, and ECMWF do bring precipitation through the
state anywhere from late next week into later in the weekend.
Needless to say, any additional precipitation would not be needed
after the earlier week rains.
&&
.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 629 PM CDT Fri Oct 5 2018
Periods of convection along with IFR/MVFR conditions are the main
concerns. Current wave of thunderstorms exiting the forecast area
with more development mainly over southern Iowa which is likely to
affect KOTM. An area of showers and iso thunder along the US 20
corridor is expected to fill in by 04z...with coverage increase
at south sites KDSM/KOTM and to near KALO as well. Most of the
overnight activity will be tied to an increasing low level jet
impinging on the upper level boundary/sfc boundaries over our
area with activity shifting south by 12z. By 14z to 17z...a
decrease in convection over the southeast is expected with only
lingering -shra and continued MVFR cigs south sites with possible
VFR cigs returning to KMCW/KFOD. /rev
&&
.HYDROLOGY...
Issued at 355 PM CDT Fri Oct 5 2018
A river Flood Warning continues for minor flooding on the Iowa
River near Tama Hwy E49. Other river Flood Warnings which were in
effect earlier for other locations have been canceled because the
streams fell below flood stage.
Attention then turns to potential impacts from the multiple heavy
rainfall events expected into next week. If QPF materializes as
advertised, then renewed/additional flooding can be expected with
many locations in river Flood Warnings. Generally, minor to moderate
river flooding is expected in many locations with major flooding at
a few to several locations. General areal flooding may occur as well
with standing water in many places as has happened in some locations
during events over the past month. Little capacity exists to deal
with additional rainfall especially north of US Hwy 30 where streams
and rivers are running high and soils are near saturation.
Also, cannot rule out the flash flood threat from this potentially
heavy rainfall. If heavy enough rainfall falls over certain areas
then flash flooding may occur. River flooding and general areal
flooding look to be the primary threats however.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Saturday afternoon for IAZ038-039-049-
050-061-062-075.
&&
$$
UPDATE...REV
DISCUSSION...Ansorge
AVIATION...REV
HYDROLOGY...Zogg
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EDT Fri Oct 5 2018
.AVIATION...
IFR and LIFR ceiling continues to expand across Lower Michigan
during the night in advance of a warm front lifting northward from
northern Indiana and Ohio. The front is also supporting showers and
thunderstorms expanding west to east across the Great Lakes from low
pressure moving through the upper Midwest into the northern Great
Lakes. The rainfall modulates an increasing component of fog as a
visibility restriction through the DTW corridor up to about PTK,
closer to the front. Farther north, less fog but equally low stratus
is expected to persist until the front moves closer and as low
pressure arrives in northern Lower Michigan. The recent decrease in
lightning strikes detected in the leading convection supports
keeping a prevailing shower in the forecast with a VCTS until better
timing of upstream activity can be obtained. Improvement of
conditions to low end VFR seems reasonable as far north as PTK
during afternoon as the warm front gains traction after morning
rainfall and moves north. FNT likely holds in MVFR and MBS in IFR
until the cold front moves through around late afternoon. This cold
front is expected to be the focus for additional thunderstorms
mainly south of FNT during late afternoon into Saturday evening.
For DTW... LIFR settled in during late evening and persists through
the night as a warm front moves in from Ohio. Fog provides
visibility restriction in between showers and possibly a heavier
thunderstorm. The front moves north of the terminal mid to late
morning followed by improvement into MVFR ceiling and then low end
VFR before a chance of storms by late afternoon into Saturday
evening.
.DTW THRESHOLD PROBABILITIES...
* High for ceiling below 5000 ft through the morning.
* Low for thunderstorm timing during the night and afternoon.
Moderate for occurrence.
* Low for cigs/vsby to fall below 200 ft and/or 1/2SM during
the morning.
&&
.PREV DISCUSSION...
Issued at 1007 PM EDT Fri Oct 5 2018
UPDATE...
Coverage, location, and intensity trends continue to be monitored
for convection as it expands over Lower Michigan overnight through
Saturday morning. While refinements continue to be made, a general
northward trend in new development is probable while prospects for
severe weather remain minimal. Locally heavy rainfall remains the
primary hazard in this setup.
Large scale forcing is being driven mainly by the influence of
complex surface low pressure that is part of the upper level trough
over the Plains and the sharp entrance region of the upper jet over
the Midwest. The evolution of these primary low pressure features
supplies a strong low level jet to the central Great Lakes while
pulling the Ohio valley warm front northward into Lower Michigan.
Ongoing convection across the Chicago area is hybrid surface based
and low level jet driven. It is moving rapidly eastward near 45 kts
into a strongly veered low to mid level wind field and a stabilizing
boundary layer both of which should at least result in some weakening
before reaching SE Michigan. New development then occurs upstream a
little farther north as the nocturnal low level jet ramps up closer
to the primary surface low and this activity ends up a little farther
north in our area as well. The trend is also favored by low pressure
consolidating in central Upper Michigan and Northern Lower by
sunrise which shifts the surface to 850 mb frontal zone slightly
north and east. As it stands now, multiple rounds of showers and
storms are expected to move quickly with each affecting a slightly
different area of SE Michigan. This suggests holding off on any kind
of flooding headlines for now and deferring to more of a short fused
advisory possibly later in the night. Also, the RAP is one of the
more aggressive models on the northward position of the warm front
and it still maintains a stable layer in the warm sector up to about
925 mb. The profile becomes more neutral mid to late Saturday morning
but appears strong enough to prevent surface based storms and/or
damaging wind gusts during the night.
PREV DISCUSSION...
Issued at 345 PM EDT Fri Oct 5 2018
DISCUSSION...
Theta e surge north of a warm from draped across the Ohio Valley has
saturated the column (PWATs around 1.5 inches) resulting in scatter
light rain showers or drizzle. With no real additional forcing or
shortwave activity expected through about midnight, see no reason to
deviate far from this forecast with persistent moist isentropic
ascent. Little change in temperatures now through tonight as we keep
the easterly component to the wind field north of the surface warm
front with excessive cloud cover and periodic rain. Temps should
hold in the mid/upper 50s.
Potentially a bit more active after midnight, especially toward
Saturday morning, as a strong mid level PV anomaly releases out of
the deepening western conus trough and passes just north of the
Great Lakes. The associated surface low will pull the warm front
northward toward southern MI as it tracks into Iowa tonight on its
way through northern lower Saturday afternoon. The front will at
first struggle to lift northward, hanging up along or south of I94
tonight, but a strengthening low level jet around 45 knots will help
speed up the northward progress through the morning hours. The first
round of showers or thunderstorms may occur with this secondary
surge of theta e along the elevated warm front. PWATs will increase
to near 2 inches, with decent shear and some elevated instability
around 500 J/kg. May get some organization to storms but they would
look to remain elevated so some hail or gust winds would occur but
not looking for any widespread strong to severe storms overnight.
We will enter the warm sector on Saturday as the low lifts through
northern Lake Huron and a cold front stretches through western lower
back into the southern Plains. Temperatures will recover by about 20
degrees over today reaching into the mid 70s. The cold front will be
the next feature to focus on for Saturday afternoon. Instability
will attempt to build through the late morning but low stratus will
attempt to delay insolation to some extent. Advection behind the
warm front may usher enough instability to make it a non factor and
an afternoon frontal timing will aide in destabilization. Stout low
level jet will overlap with the right entrance region of the 140
knot upper level jet over the northern Great Lakes. This plus
frontal forcing, around 1000 J/kg of SCAPE and 30 knots of bulk
shear should be sufficient for storm development. Next question is
will it initiate over SE MI or hold off til it passes just south and
east? Most hires models indicate development around Flint then
working SE from there through the late afternoon. There remains a
marginal risk of severe storms Saturday afternoon.
Ridge across the SE states will then build up into the southern
Great Lakes forcing the front back north through lower MI Sunday.
The front draped across the state with weak waves ejecting out of
the longwave trough will keep chances of precipitation in the
forecast through the end of the weekend. May see a decent
temperature gradient across lower MI as the front lingers over the
area with 50s across Mid MI and low 70s along the Ohio Border.
Warmth returns to the region on Monday as the front is pushed
northward by the strengthening ridge over the eastern CONUS,
allowing warm southerly flow to set up locally. Highs around SE
Michigan will reach the upper 70s to lower 80s Monday through
Wednesday. The displacement of the front should keep better chances
for precipitation over northern Michigan through the middle of the
week, but isolated to scattered showers and storms will be possible
each afternoon in this summer-like air mass. The better chance for
widespread precip returns late Wednesday into Thursday afternoon as
troughing moves in from the west and drives a cold front through.
This front will usher in a more seasonable air mass for the
remainder of the week, with high pressure filling in and bringing
the return of quiet weather.
MARINE...
Moderate east to southeast flow will persist through early Saturday,
as the region remains between high pressure over Canada and low
pressure lifting into the western great lakes. Gusty conditions at
times, peaking near 25 knots over northern portions of lake Huron.
The persistent onshore flow will maintain elevated waves along outer
Saginaw Bay and portions of the Lake Huron nearshore waters,
especially from Port Austin to Port Sanilac. Winds briefly turn
southwesterly on Saturday as low pressure tracks northeast across the
central great lakes, and a warm front lifts north across the region.
This will result in a period of unsettled conditions, with scattered
to numerous showers and thunderstorms possible tonight into
Saturday. Northerly winds develop in the wake of this low Saturday
night, before becoming northeasterly on Sunday. Renewed onshore flow
will lead to another period of elevated waves for the latter half of
the weekend.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....BT
UPDATE.......BT
DISCUSSION...DRK/TF
MARINE.......MR
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Hastings NE
700 PM CDT Fri Oct 5 2018
.SHORT TERM...(This evening through Saturday)
Issued at 334 PM CDT Fri Oct 5 2018
Skies have remained mostly overcast today across the forecast
area, which has kept temperatures from climbing much higher than
the low 50s for all but the northernmost and southernmost parts of
the area. This evening, we will be impacted by a cold front as it
moves across the area. This front will be moving into
northwestern portions of the forecast area shortly. Winds will
become northerly behind this boundary, possibly gusting as high as
35 MPH. Winds won`t be nearly as strong as they were with our
previous cold front since our mixing heights are substantially
lower.
As this front intersects more unstable air to the south,
thunderstorms are expected to develop near and south of the KS/NE
border around 01-02Z. Despite the cloud-cover, the RAP shows up to
1000j/kg of elevated CAPE and around 50kts of deep-layer shear.
Because of this, we may see a few strong to severe storms. Given
the elevated nature of the storms, hail would be the main threat,
but an isolated severe wind gust is possible if we can mix down
strong winds behind the front.
Later tonight, the attention turns to the threat for frost over
northwestern portions of the area. The low temperature forecast
has trended downward just a bit, and we went ahead and issued a
frost advisory for the coldest areas. That said, there is some
uncertainty on how cold we actually get. We have gotten colder
than forecast several nights this week so I favored the cold side
of guidance, but steady winds and lingering cloud cover could keep
temps a bit warmer. The evening shift will have to keep a close
eye on the short-term trends.
Lingering chances for showers continue over southern portions of
the area on Saturday, although most of the area will remain dry
through the daytime hours. High temperatures are expected to be in
the mid 50s.
.LONG TERM...(Saturday night through Friday)
Issued at 334 PM CDT Fri Oct 5 2018
By Saturday evening and overnight, a deepening trough over the
western CONUS will allow for warm and moist air to push back
northward into the area. As it does so, we may see spotty showers
or drizzle develop through Saturday night into Sunday.
Coverage of rain ramps up substantially on Sunday and Monday as
the upper trough continues to deepen and eventually cut off over
the southwestern US. There may be enough instability for a few
thunderstorms, but locally heavy rain will be the main threat. Models
continue to indicate that the heaviest rainfall totals will occur
over eastern and southeastern Kansas, stretching up into
southeast Nebraska. This will put the main threat for flooding in
southeastern portions of the local forecast area.
The surface low finally ejects through the area on Tuesday,
allowing rain to gradually end from west to east. Models show
5-day rainfall totals of 3-5 inches over southeastern portions of
the area, with most of the area seeing at least an inch.
Mostly dry conditions are expected through Wednesday as surface
high pressure builds in from the north. Depending on clearing,
Wednesday night could be another potential for frost development
over western portions of the area. That said, there is too much
uncertainty to mention this in the grids at this point.
Thursday should remain dry as well, but the forecast becomes more
uncertain as we go into Friday. The GFS and the previous run of
the EC were in surprisingly good agreement on bringing the
remnants of a tropical system out of the Pacific and into the
area. That said, the latest EC is much weaker with this system and
we will likely continue to see differing model solutions over the
next several days. Nevertheless, this will be the next time
period to watch for precipitation.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 651 PM CDT Fri Oct 5 2018
North winds will increase this evening behind a cold front and
will be rather gusty throughout the overnight hours. We do expect
the ceilings and visibility to improve this evening behind the
front with increased mixing due to the gusty winds. The MVFR
ceilings at TAF issuance should give way to VFR conditions by 10
or 11 pm if not sooner.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Frost Advisory from 4 AM to 10 AM CDT Saturday for NEZ039-046-
060.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Grand Rapids MI
843 PM EDT Fri Oct 5 2018
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 330 PM EDT Fri Oct 5 2018
Occasional showers and thunderstorms will occur over the weekend
due to a stalled frontal boundary. The front will lift north of
the area on Monday and summerlike temperatures with only isolated
showers and storms are expected for the early to middle part of
next week. Cooler temperatures will arrive toward the end of
the week with the passage of a cold front, which will also bring
another round of showers and thunderstorms.
&&
.UPDATE...
Issued at 845 PM EDT Fri Oct 5 2018
As expected, showers and thunderstorms have developed along (north
of) the 850 mb (surface) warm front across eastern Iowa and
northern Illinois. However, the activity has developed earlier and
further south than previously advertised by the numerical model
guidance, currently tracking generally along the I-88 corridor.
Based on the SPC RAP mesoanalysis, the 850 mb warm front curves
upward into Lower Michigan suggesting that perhaps the upstream
convection may make a northward push; however, it seems the most
likely scenario is for the bulk of the activity to continue an
eastward progression favoring areas along and south of I-94.
With PWATs approaching 1.6 to 1.7" (nearing the 00Z OCT 6 record
high at DVN upstream of our area) within a strengthening low-
level jet beneath upper-level diffluence in the right entrance
region of the upper- level jet, locally heavy rainfall of 1-3" is
expected where storms train overnight. In fact, radar-estimated
rainfall rates are already approaching 1-2"/hr in the strongest
storms, leveraging confidence that indeed a heavy rain event is
setting up. Yet, it seems the axis of heaviest rainfall will be
along and south of I-94 (if not even further south), thus limiting
the potential impacts of ponding of roadways and low-lying areas
across our area.
It is also worth noting that a few cells overnight may be on the
stronger side with 0-6 km shear near 30 kts and MUCAPE
approaching 1000 J/kg. Small hail appears to be the main threat,
even though mid-level lapse rates are fairly poor. The threat of
stronger storms will be tied to the threat of heaviest rain
tonight (meaning this too may end up south of our area of
responsibility).
Otherwise, it`s downright crummy out there with widespread
"heavy" mist as told by locally 1-2 mile visibilities. Such
conditions are expected to remain in place through Saturday
morning.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 330 PM EDT Fri Oct 5 2018
Most places will see a half inch to an inch of new rain over the
weekend, although localized heavy amounts in excess of 2 or 3
inches are possible - particularly for areas near and south of
I-96. There is also a marginal risk of a few strong to severe
storms containing high winds and/or hail, mainly on Saturday
afternoon south and east of a line from AZO to LAN.
Guidance continues to offer varying solutions on convective
trends and rainfall amounts in the short term. Regardless of the
specifics, a synoptic pattern conducive to heavy rainfall will be
present over the weekend.
First, a narrow tropical connection/atmospheric river can be seen
in water vapor imagery extending from Chicago southwest across TX
and Mexico into the ern Pacific. PWATs within this corridor are
around two inches. Second, a 150 kt upr level jet streak/segment
will be positioned to our north much of the weekend, yielding
strong upper level divergence/lift due to right entrance region
dynamics. Finally, a low level jet of 30-50 kts will be
occasionally aimed at the frontal boundary across srn Lwr MI over
the weekend - probably strongest in the overnight and early
morning hours.
The current signal in the CAMS for tonight and Saturday is that
clusters of elevated storms containing locally heavy rain will
impact the area from about midnight tonight through mid morning
Saturday. Believe the svr wx threat is very low through 12Z Sat
since sfc based instability does not really reach I-94 until after
12Z. The thing to watch for severe weather looks to be a band of
storms which may form in the warm sector se of GRR in the
afternoon, peaking roughly 4 PM-8 PM. JXN area most susceptible
before the sfc front slips south again. The NamNest is most
aggressive in this regard.
Looks like we stay on the cold side of the sfc front from
Saturday night through Sunday night. However more clusters of
elevated storms with additional heavy rain remain possible during
this time. The heavy rain threat should finally end by Monday
afternoon as the warm front lifts off to the north. Then probably
quieter for a few days in the warm sector with just widely
scattered diurnal showers and storms. Current timing of the cold
front and the probable end to this pattern is around 12Z next
Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 638 PM EDT Fri Oct 5 2018
Crummy conditions will further deteriorate as the evening goes
on. A heavy mist has developed at GRR and will likely spread to
all TAF sites as the evening goes on leading to IFR to LIFR
conditions. Widespread showers and storms are expected overnight
leading to bonafide LIFR conditions. The heaviest storms are
expected to impact AZO/BTL/JXN where VLIFR conditions are
possible, especially between 06-12Z. Widespread mist and low cigs
(e.g. IFR to LIFR conditions) are expected to persist at all TAF
sites into the morning hours before improving somewhat during the
afternoon hours. Renewed convective development is possible near
JXN during the late afternoon hours.
&&
.MARINE...
Issued at 330 PM EDT Fri Oct 5 2018
Predominately offshore flow will prevail over the weekend, and
this should keep wave heights on the lower side. A brief period of
stronger north-nw flow is possible Saturday after a sfc low
passes by.
&&
.HYDROLOGY...
Issued at 330 PM EDT Fri Oct 5 2018
River levels are dropping on both large and small
streams in our area as several days have now elapsed since the
rounds of heavy rain earlier in the week. Water levels are still
elevated for this time of year, but have fallen below bankfull at
all locations. Unfortunately, we are about to enter a weather
pattern that will feature several rounds of heavy rain across our
area.
Frustratingly, the exact timing and placement of the heaviest rain
bands is still a bit uncertain, but by the time Sunday afternoon
rolls around almost all of West Michigan will have received an inch
of rain, with some locations likely approaching 2 inches or more.
The larger rivers (Muskegon, Grand, and Kalamazoo) will again begin
to rise substantially, but should be able to absorb this amount of
water without any significant flooding. The medium-sized
tributaries, especially those along the Grand River (Looking Glass,
Flat, and Thornapple) are less equipped to handle this amount of
water right now, and will likely see water levels approach bankfull
by early next week. Thankfully, at this point it does not look like
these streams will see significant flooding.
The other concern we have, heading into this renewed wet weather
pattern, is that soils are still nearly saturated. This means that
even areas that could normally take an inch or two of rain without
much issue may see increased standing water on roads, in fields, and
on small streams. In addition, urban areas that tend to have
drainage issues with heavy rain should remain vigilant this weekend
in case these heavy rain bands move repeatedly overhead.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Borchardt
SYNOPSIS...Meade
DISCUSSION...Meade
AVIATION...Borchardt
HYDROLOGY...AMD
MARINE...Meade
Area Forecast Discussion
National Weather Service Indianapolis IN
1144 PM EDT Fri Oct 5 2018
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 317 PM EDT Fri Oct 5 2018
A persistent frontal boundary will serve as the primary feature
influencing weather across the region over the next several days. As
the boundary oscillates back and forth across the area through the
middle of next week...periodic chances for thunderstorms will exist.
Summer levels of heat and humidity are expected through early next
week with temperatures dropping back to more normal levels late week
as the front finally kicks through the area.
&&
.NEAR TERM /Rest of This Afternoon and Tonight/...
Issued at 317 PM EDT Fri Oct 5 2018
Convection continues to impact areas from Muncie...to the Indy metro
southwest into the lower Wabash Valley this afternoon as an upper
level wave tracks through the area. The presence of the warm front
across the region is also assisting the storms along the I-70
corridor. The primary impact from the convection so far has been
locally torrential rainfall with some areas picking up 0.50 to 1
inch in less than a hour. 19Z temps ranged widely across the frontal
boundary...with 60s and 70s across area near and north of I-70 and
mid to upper 80s across southern counties.
The initial focus remains on the current convection which will shift
east over the next few hours. The warm front is contributing to the
convective coverage near and north of I-70 with activity more
scattered over the lower Wabash Valley where greater instability is
serving as the primary driver to development. Have not been
impressed with the handling of the convection this afternoon via
bulk of the hi-res guidance. Models have been consistently focusing
storms further north than where they currently are...likely a
byproduct of placing the warm front further north than it currently
is. Will focus higher pops over the southeast half of the forecast
area for the next few hours to capture current activity. The main
impact will continue to be heavy rainfall...aided by deep moisture
profiles and precip water values currently hovering near climo max
levels for early October in the 1.6 to 1.8 in range.
Another wave tracking along the front will move into the western
Great Lakes this evening and will aid in finally lifting the warm
front north of the region. The HRRR has consistently hinted at
renewed development over the northern Wabash Valley this evening in
the vicinity of the northward moving front. While this area is
starting to see sunshine and destabilization...am somewhat skeptical
of this idea with little in the way of forcing aloft likely to be
present. Will carry low pops through the evening in northern
counties...but cannot justify much higher at this point.
After this point...convective development along the front off to our
northwest will migrate back towards northwest counties during the
predawn hours and will carry low pops there. Further south...most of
the forecast area will remain dry after midnight through daybreak
under the influence of the upper ridge.
Temps...likely to see jumps in temperatures over the next few hours
as skies clear behind the current convection. A muggy...sultry
overnight is expected with lows in the upper 60s and lower 70s. An
overall model blend will work well.
&&
.SHORT TERM /Saturday through Monday/...
Issued at 317 PM EDT Fri Oct 5 2018
Forecast challenges will remain focused on rain and storm chances
along with temperatures as summer stubbornly hangs on through the
holiday weekend.
Upper level flow over the country will slowly and steadily amplify
through the weekend. A deep trough will carve out over the
intermountain west...prompting a flexing of the downstream ridge
over the eastern U S. An anomalously and unseasonably strong Bermuda
high will shift its center from the southeast states to the Mid
Atlantic region through the period. In between...a strong
southwesterly flow will pump deep moisture with a Gulf of Mexico and
Pacific origin into the Mississippi Valley and Great Lakes where it
will interact with the quasi-stationary frontal boundary and
generate multiple rounds of convection and heavy rainfall through
Monday. The position of the ridge center with respect to central
Indiana will keep primary impacts from the front largely confined to
the northwest half of the forecast area for much of the short term
while maintaining a summer airmass over much of the Ohio Valley.
While convective threats will exist periodically throughout the
holiday weekend...the greatest potential will exist at points when
the frontal boundary drifts south closer to or into northern parts
of the forecast area. That appears most likely through Saturday
evening as the model suite shows nice agreement in the boundary
drifting into north central Indiana late day Saturday. Will employ
highest pops through Saturday night with primary focus over the
northwest half of central Indiana in closest proximity to the
boundary. While a few strong storms with gusty winds will be
possible...the heavy rainfall will continue as the primary threat
from convection as the favorable southwest flow aloft...freezing
levels in excess of 13-14kft and precip water values persisting at a
climo max for early October all support potential for storms to dump
a ton of rain in short order in some spots.
By Sunday and Monday...heights aloft will rise as the ridge center
refocuses over the Mid Atlantic and the front is forced back to the
northwest. Model soundings show a developing cap with instability
aloft. With little forcing aloft present...this will trend towards
convection being much more isolated and driven primarily by the
moisture and any available instability courtesy of diurnal heating.
Will drop pops back substantially as a result from Sunday morning
on.
Temps...the weekend temperatures are likely to approach the Columbus
Day weekend 2007 temps with afternoon highs in the mid and upper
80s. Will not at all be shocked if a few locations can get to 90
either. Record highs may be just out of reach at Indy but we are
likely to get within a couple degrees each of the next three days.
Overnight lows will range from the mid 60s tho the lower 70s at
night. Leaning towards the high end of a model blend will work
well.
&&
.LONG TERM /Monday night through Friday/...
Issued at 255 PM EDT Fri Oct 5 2018
Ensembles in good agreement that a bubble of high pressure will be
moving east off the east coast and southwest as an upper system
lifts northeast from the desert southwest to the northern Plains and
then Great Lakes next week. At the surface, a strong cold front is
expected to slide southeast across the area during the middle and
late parts of next week. Southerly flow will bring in very warm and
moist and unstable air to central Indiana along and ahead of the
front. The best chance for thunderstorms looks to be Wednesday night
and Thursday with the front. Could also see pre-frontal convection
by Tuesday.
The possibility exists that a tropical storm may form over the Gulf
and get ingested into the southerly flow along and ahead of the
front. But even if that does not occur, potential is there for heavy
rain.
Well above normal temperatures will likely fall to normal to below
in the wake of the front. Good confidence in blend trends if not
with close precision.
&&
.AVIATION /Discussion for the 06/06Z TAF Issuance/...
Issued at 1138 PM EDT Fri Oct 5 2018
Periodic chances for showers and thunderstorms will continue
throughout the TAF period as a frontal boundary meanders over the
region. The best chances this morning will be at KLAF/KIND/KHUF
due to development along front to the northwest but KBMG should
stay dry. Conditions will generally be at VFR levels, but cannot
rule out any quick drops to MVFR category. Meanwhile, winds will
generally be southwesterly at 6 to 11 kts.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...Ryan
NEAR TERM...Ryan
SHORT TERM...Ryan
LONG TERM....MK
AVIATION...TDUD
Area Forecast Discussion
National Weather Service Memphis TN
843 PM CDT Fri Oct 5 2018
.DISCUSSION...
Skies are mostly clear across the forecast area this evening with
temperatures in the 70s. There were a few showers that developed
this afternoon mainly across portions of northeast Mississippi but
all that activity is gone. A quiet weather night is in store with
temperatures remaining well above normal. Current forecast looks
good with no update needed.
ARS
&&
.PREV DISCUSSION... /issued 321 PM CDT Fri Oct 5 2018/
At 3 PM CDT... A warm afternoon more akin to early September than
early October is ongoing around the Mid-South. High temperatures
in the low 90s have been realized at many locales, with dewpoint
temperatures in the upper 60s and even lower 70s. Radar trends
have been dry, though the HRRR still suggests some light showers
could be possible over north Mississippi throughout the remaining
afternoon hours.
A broad upper ridge will keep conditions warm and dry for much of
the next week. The ridge, currently centered over eastern GA and
western SC, will only gradually move through the end of the
weekend. This will keep conditions dry and warm across the local
area. Weekend high temperatures will be in the upper 80s, in
excess of 10 degrees warmer than normal.
The ridge will gradually shift east early next week, just as an
amplifying trough across the western CONUS moves into the Plains.
This break in the ridge`s grip on the region will allow for
increased rain chances. In addition, the flow aloft will become
more southwesterly as the surface flow becomes more southerly.
This will keep warm, moist air advecting into the region, keeping
conditions warm and humid.
By midweek models are in decent agreement of a front approaching
and moving through the region. This will bring the best
precipitation chances for the entire week. Also, a tropical system
with the potential to impact the Gulf coast could move north
midweek, but models currently keep its moisture east of the
region. Thus have currently gone with chance POPs for Wednesday
and into Thursday.
Models diverge on solutions behind the front for late next week,
with the ECMWF currently keeping conditions dry and the GFS
bringing more rain chances for late next week. Regardless,
temperatures should be a few degrees cooler by next weekend.
ZDM
&&
.AVIATION...00z TAFs
VFR conditions will prevail through the TAF cycle. Winds will be
from the South, light overnight, 5-10kt tomorrow.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Melbourne FL
922 PM EDT Fri Oct 5 2018
.UPDATE...
Tonight...The GOES Precipitable water product showed an area of
higher values over the south half of the area. The HRRR model shows
drier air advecting in from the east but the GFS only shows gradual
erosion of the moisture ribbon. A small batch of showers that was
offshore the Space/Treasure Coast has recently diminished, but this
was most likely due to weakening low level easterly winds. There
looks to be enough moisture convergence for Atlantic cloud lines to
produce isolated showers overnight, so will maintain a slight chance
for coastal showers, mainly from Cape Canaveral southward. The
weakened onshore flow will allow min temps to drop into the lower
70s, except for a few mid 70s along the Space/Treasure Coast.
&&
.AVIATION...
Mainly VFR through Sat. Isolated SHRA may affect coastal terminals
tonight/early Sat with brief MVFR CIGs/VSBYs then transition to the
interior terminals in the afternoon but coverage looks too low for
any TEMPO groups or even vicinity terminology for now.
&&
.MARINE...
Tonight-Saturday...A high pressure ridge along the eastern seaboard
will maintain an easterly wind flow. Speeds have dropped off to 10
knots or less across the northern/central waters as the southern
flank of the ridge was nosing in, but guidance is showing the
pressure gradient starting to slowly tighten Sat with winds picking
up to 10-15 knots by late afternoon. Long period swells propagating
into the waters from distant Tropical Storm Leslie will keep seas
elevated to 5-6 feet in the open Atlantic. Conditions will continue
to be hazardous near inlets during the outgoing tide. No changes to
the previous forecast except to include an exercise caution
statement in the southern waters.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Lascody/Volkmer
Area Forecast Discussion
National Weather Service Raleigh NC
927 PM EDT Fri Oct 5 2018
.SYNOPSIS...
A weak backdoor cold front will drift south into the area overnight
and will stall across our region through Saturday before
dissipating. Meanwhile, an area of strong high pressure aloft will
remain across the area through next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 927 PM Friday...
Although a southward propagating convective outflow boundary has
resulted in a pre-frontal NELY wind shift across much of the area,
the true cold front across southern VA has moved very little over
the past 6 hours, with sfc metar obs KIXA and KASJ just now showing
signs of low-level dry air working it`s way into the far NE coastal
plain counties. Convection associated with both the front near the
VA border and the outflow boundary that has made all the way down to
our southern tier counties(Hoke-Cumberland_Sampson), has all but
dissipated. Given the lack of upstream sfc pressure rises across the
Mid-Atlantic region(parent high center over SE Canada), not sure how
much farther south the front will progress, with a good chance of
the front stalling out along the Highway 64 corridor. Will keep an
isolated pop across the northern half of the forecast area, invof
the front. GOES-16 Night/Fog Channel(10.3-3.9um)shows an extensive
IFR to MVFR stratus deck across eastern Va spreading south into the
NC within the NELY flow. Hi-res HRRR suggests these overcast low
clouds will envelop all of central NC by 09 to 10z. Overnight lows
ranging from mid/upper 60s NE to lower/mid 70s south.
&&
.SHORT TERM /SATURDAY/...
As of 155 PM Friday...
Little change in the pattern on Saturday with the front stalled
invof the NC/SC border and the mid level ridge centered right over
NC. While the GFS appears fairly generous with QPF along and south
of the Hwy 24 corridor (again, along or just north of the front),
many of the CAMS are less robust with shower/tstm development given
the aforementioned ridge. So for now, will advertise PoPs ranging
from 15-30%, highest south and southwest zones, and lowest NE zones.
High temps will range from around 80 north (well north of the front)
to mid-upr 80s south (along, or perhaps even just south of the
front).
Any isolated showers that do form tomorrow will quickly fade
Saturday night, leaving the rest of the night partly cloudy with
some fog development possible again north of the boundary. Lows 65-
70.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 300 PM FRIDAY...
Warm conditions continue for the end of the weekend and into early
next week as the upper level ridge remains encamped over the area.
expect high temperatures in the mid to upper 80s across much of the
CWA with the exception of the Triad and VA border counties which
will come in a few degrees cooler, in the lower 80s. Some slightly
cooler air moves in for the mid week time frame, as the upper ridge
begins to break down. Through midweek, southeasterly surface flow
will bring some moisture to at least southern and western portions
of the forecast area and as a result will carry slight chance to low
end chance pops in this area with isolated to scattered showers and
thunderstorms possible but severe chances look very meager given the
lack of upper level support.
End of the forecast is really in flux at this point as models take
different takes on how to handle some tropical moisture and the
advancement of a cold front from the west. The upshot is however
that the end of the week looks to be much wetter than the front half
and will increase pops to high chance levels for the end of the week
with the possibility of some periods of heavy rain possible.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 155 PM Friday...
VFR conditions continue across all TAF sites as of 7pm Friday
evening. Deteriorating aviation conditions are likely overnight as
cool, moist, northeasterly flow becomes established behind the
cold front sinking south through central NC. This will allow for a
rather robust area of low-level stratus and intermittent VSBY drops
in the MVFR/IFR range, with some LIFR not out of the question. CIGS
will likely begin dropping just after midnight, settling to 400 to
600 feet by sunrise on Saturday. Conditions are expected to slowly
improve on Saturday morning, with at least MVFR CIGS likely to stick
around for much of the day. Some breaks will be possible by mid to
late afternoon, especially at KRDU/KRWI/KFAY, where a quick
shower/storm can`t be ruled out.
After 00z Sunday: IFR to MVFR conditions possible Sunday
morning. Generally VFR conditions expected for the rest of the
extended period as a ridge aloft remains overhead for several days.
A few afternoon showers or isolated thunderstorms could cause some
pockets of sub-VFR conditions as could some early morning low
fog/stratus.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Haines
NEAR TERM...CBL
SHORT TERM...np
LONG TERM...Ellis
AVIATION...JJM