Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/29/22
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
911 PM CDT Wed Sep 28 2022
Issued at 903 PM CDT Wed Sep 28 2022
The forecast for the overnight hours is in good shape and no big
changes needed at this time. Will continue to see breezy/gusty
southerly winds through the night, which will keep low temps up
into the upper 40s to mid 50s for most areas. An area of mid-level
clouds will move east across the CWA overnight as a weak/dry
shortwave moves through. There are some weak radar returns to the
west under the mid-level clouds, but nothing reaching the ground.
HRRR suggests maybe a couple sprinkles or a light shower or two
drifting across the northern CWA overnight, but with rather dry
low levels in place. Will leave forecast dry for the time being.
UPDATE Issued at 630 PM CDT Wed Sep 28 2022
Aviation discussion updated below for the 00Z TAFs.
.SHORT TERM...(This Evening through Thursday Night)
Issued at 224 PM CDT Wed Sep 28 2022
Quiet weather expected for the short term with the main concern
being gusty winds on Thursday across the eastern/northeastern CWA
with ongoing dry conditons. The lowest RH values looks to be across
our central CWA ranging from 21%-35%, with the drier conditions
across central/south-central SD. There could be some fire concerns
with the gustier winds for Thursday, even though we are expecting
our minimal RH values to be a little higher.
Models are in good agreement with an overall ridging pattern aloft
with an embedded shortwave that will push across the Upper Midwest
and Northern Plains overnight through Thursday, just bringing a few
scattered clouds...followed by a shortwave ridge behind. A cutoff
low will push onshore off the Pacific overnight and push east with
the center of the low over ID/MT by early Friday morning and pretty
much staying stationary. NBM surface winds continues out of the
south/southeast through early Friday with 850mb winds mainly out of
the south/southwest overnight. This will keep our overnight lows
warmer than last night so frost/freeze will not be an issue. Warmer
air shifts further east Thursday as RAP 850mb temps across our
western CWA will range from ~21-23 degrees Celsius with 925mb temps
up to ~31 degrees Celsius! This is above average for this time of
year. With diurnal heating, this will allow our high temps to reach
well in the upper 70s through the mid/upper 80s, with some areas of
our sw CWA nearing 90! I added in one part NBM 90 to our high temps
for Thursday to show for this. Our eastern CWA, highs will range in
the mid/upper 70s.
Behind the high, steeper pressure gradients continue to dominate the
area. 850mb winds from GFS/ECMWF indicate up to 35-40 kts across the
central/eastern CWA by 00Z Thursday and this continues into the
overnight hours. The higher winds a this level push over the eastern
CWA for Thursday so I blended in some NBM 90 due the gustier winds
at the surface we will continue to experience. Gusts would reach up
to around 35kts, mainly over the Coteau.
.LONG TERM...(Friday through Wednesday)
Issued at 224 PM CDT Wed Sep 28 2022
By 12Z Friday we`ll be looking at the 500mb ridge over the Northern
Plains shifting east in response to the large and slow moving low
nearing from ID/MT. The exact timing and strength of the low is in
question, with at least the operational 12Z run of the GFS being more
progressive than most options. It becomes more of an open wave
Sunday night as it moves through the Dakotas Monday. Given the
variability in forecast models, the low could linger over SD as late
as Wednesday. This gives us lower confidence in the pops and wind
forecast for Sunday night through at least Tuesday night. At the
surface, low pressure over southwestern SD at 12Z Friday will nearly
stay in place as it weakens and elongates through western NE/KS and
far eastern CO. While central SD has at least a slight chance of
showers Friday night on, central SD mainly just gets clouds. An
inverted V sounding Sunday afternoon could equate to strong winds
and dry conditions. The surface low may finally get into eastern
SD/western MN Monday night into early Tuesday. Drier air looks to
return Tuesday and Wednesday. Temperature wise, we should see slowly
moderating highs back to near average conditions by Tuesday and
Wednesday of next week.
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 630 PM CDT Wed Sep 28 2022
VFR conditions are forecast through the TAF period. Breezy/gusty
southerly surface winds will persist through the period as well.
LLWS will become a concern overnight into early Thursday morning
and have inserted mention of this into the TAFs.
Area Forecast Discussion
National Weather Service Cleveland OH
940 PM EDT Wed Sep 28 2022
High pressure will build into the region late tonight and
Thursday, gradually moving eastward through the weekend. The
remnants of Ian will move into the Appalachians by Sunday and
Monday followed by high pressure returning to the area.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
9:30 PM Update...
Lake-effect rain showers and clouds will stick around for the
next few hours with clouds lingering overnight. No major
changes needed with this forecast package. Made minor tweaks to
PoPs and temperatures to reflect hi-res guidance and current
6:30 PM Update...
Lake-effect rain showers continue to spread across those along
and east of I-77 this evening. Winds across the lake remain
northerly to northwesterly with this update which is causing the
orientation of these lake-effect showers. The expectation is
that the showers will finally dissipate late this evening as
high pressure builds southeastward. Low level RH values decrease
this evening, cutting off moisture necessary for the lingering
showers. Winds over the lake will also shift and become
northeasterly as high pressure builds. Lows tonight will drop
into the mid 40s, with higher values near the lakeshore closer
to 50 degrees.
Lake-effect showers continued for yet another day today, and
current radar shows widespread coverage in a NNW fetch across
Lakes Huron and Erie. A strong 1032 mb surface high over the
Upper Midwest is trying to build in, but deep mid/upper
troughing remains anchored over the eastern Great Lakes causing
moist cyclonic flow to hold on across our region. This continued
cyclonic flow, lake to 850 mb Delta T`s of 17 to 18 C given 850
mb temps around 2 C, sufficient equilibrium levels of 7 to 8
thousand feet, and good moisture remaining from the surface
through 700 mb with minimal shear has allowed these showers to
persist. Daytime heating has also resulted in instability type
showers popping up over much of northern Ohio and western PA
this afternoon. As the evening wears on, conditions will finally
start to improve as the high builds farther SE, resulting in a
lowering inversion and decreasing boundary layer moisture. The
drier air and lowering inversion combined with the short 360
degree fetch will finally dissipate most of the lake- effect
showers. However, the boundary layer flow becoming more NE
tonight in response to the surface high sliding into lower
Michigan will lengthen the fetch a bit, and RAP BUFKIT soundings
are slow to scour out the moisture below 800 mb, so feel that
isolated showers or a weak band or two will persist from the
Islands through areas near and west of the central highlands.
Increasing shear besides the shallower moisture and lower
inversion will keep this activity light, but extended slight
chance PoPs in these areas through the night. It could even fall
as drizzle given the dry air above 800 mb. The lake-effect
clouds tonight will keep lows from really tanking, so generally
expect low/mid 40s across inland areas and upper 40s to low 50s
within 15 miles of the lakeshore.
For Thursday, the mid/upper trough will lift out with quasi-zonal
flow taking over across the northern tier of the U.S. ahead of an
upper low meandering across the Intermountain West. This combined
with the surface high becoming centered over southern Ontario and
Ohio will finally end any remaining lake-effect Thursday morning and
allow for mostly sunny skies for the afternoon. Several HREF members
still hold onto a few sprinkles downwind of the lake in north
central Ohio, but given the described pattern, kept the forecast dry
Thursday morning with any PoPs gone after 12Z. Highs Thursday will
moderate into the upper 50s/low 60s, but still about 10 degrees
below normal for late September. Clear skies and light winds
Thursday night will lead to optimal radiational cooling, so lows
should easily fall into the upper 30s across inland areas, except
low/mid 40s within 15-20 miles of the lake. Interior NW PA has the
best potential for frost with mid 30s likely, but it is possible in
sheltered valleys of NE Ohio and near the central highlands too.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The short term forecast period should be relatively quiet with high
pressure across the region. The deep trough the plagued the area
over the weekend and early this week will be long gone and some
modified upper ridge will allow for temperatures to return toward
normal. The remnant low of Hurricane Ian should be well southeast
and generally not expecting any precipitation at this time.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
For Sunday into Monday, the main long term forecast concern is the
remnants of Hurricane Ian and where this low may go. While prior
forecast runs suggest this low entering the Ohio Valley, recent
guidance suggests that strong Canadian high pressure will build from
the north and try to block this system from entering the region.
Therefore, have just some slight chance PoPs for now but this may be
overdone at this point. High pressure appears to fully build in by
Monday and will allow for dry weather for the first couple days of
next week. Temperatures will remain slightly below normal for the
period with the cooler high pressure building into the region.
.AVIATION /00Z Thursday THROUGH Monday/...
Mainly VFR with areas of upper end MVFR ceilings this evening. MVFR
ceilings mainly occurring at KCLE with brief periods at KYNG/KCAK
due to lake-effect showers. Conditions will improve around 02-04Z
this evening as rain showers dissipate as drier air enters the
region. High pressure and a drier air mass will lead to
widespread VFR conditions through the remainder of the TAF
period at all terminals.
Winds have begun to shift and become north-northeasterly remaining
near or below 12 knots. Winds will remain generally northerly
through the end of the TAF period, at 10 knots or less.
Outlook...Non-VFR possible in isolated showers Sunday and Monday.
The trough across the region will finally get the boot as high
pressure builds southeast across the Great Lakes region for Thursday
into Friday. Conditions are already improving this afternoon and
waves will finally fall below 4 ft this evening, ending the SCA and
Beach Hazards for this event. Northwest flow will continue over the
lake through this evening eventually coming around to the northeast
for Thursday on the south side of high pressure. East to northeast
flow will be favored into Friday as high pressure departs to the
east. Do not expect winds to be all that strong with the surface
high through Friday and suspect no marine headlines for Thursday or
Friday. For Saturday and Sunday, the remnant low of Hurricane Ian
reaches the southern Appalachians while strong Canadian high
pressure builds from the north. This will set up a favorable
pressure gradient for the lake and winds to 20 knots can be expected
for portions of the weekend. This flow will be northeast and with
the long fetch of the lake, suspect a Small Craft Advisory will be
needed for the western half of the lake. At this point, it appears
that the high pressure to the north will win out and light easterly
flow should take over the lake for early next week.
OH...Beach Hazards Statement until 4 AM EDT Thursday for OHZ010>012.
MARINE...Small Craft Advisory until 4 AM EDT Thursday for LEZ145>147.
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
737 PM EDT Wed Sep 28 2022
Upper level trough keeps abundant clouds tonight. High pressure
slides southeast over our area, bringing dry weather Thursday
thru the end of the week. Unsettled weather this weekend with Ian.
.NEAR TERM /THROUGH THURSDAY/...
As of 732 PM Wednesday...
Abundant low to mid level clouds and a few light rain showers will
continue to advect from the Great Lakes into our area this evening.
It is uncertain whether these clouds will dissipate overnight, as
the upper level trough axis crosses the area, and the high pressure
continues to bring CAA under northerly flow. Winds aloft will stay
about 15 to 20 knots overnight. These clouds and winds will likely
suppress dense fog formation, and favor low stratus instead. Some of
the most protected river valleys may still observe fog during the
predawn hours. Another indication that low stratus would develop is
the presence of the thermal through at H850 over the northeast
mountains. The RAP model shows this thermal through spreading
southwest, perhaps developing a low stratus deck across most of WV
Therefore, will increase cloud cover overnight targeting more low
stratus than dense fog.
As of 235 PM Wednesday...
A few showers will develop north of I-64 this afternoon and
evening as an upper low swings east overhead. At the same time,
a surface ridge builds underneath from the northwest. A large
area of low to mid level moisture the Ohio Valley to the
Appalachian mountains will continue to advect from the northwest
along a cooler air mass. This brings a challenge to the forecast
overnight for low clouds and patchy fog. Patchy fog will be
limited as low clouds continue to overspread from the north.
Quiet cool conditions are expected on Thursday as cool northerly
flow ensues behind the exiting low.
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 150 PM Wednesday...
Dry conditions to prevail across the area Thursday night through
much of Friday. Cloud cover will be on the increase however, as
remnants of Ian move into the southeast U.S., and eventually
closer to our area.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 1225 PM Wednesday...
Moisture from remnants of Ian will be affecting the area in the
first part of the long term period, with rains starting late
Friday night/early Saturday morning. This has the potential to
be a prolonged period of rainfall across the area, depending on
when exactly the models kick the system off to our east. General
consensus is for Ian to move into SE coast by late Thursday
night, before gradually rotating WNW towards the Appalachian
region, where it has the potential to linger into early next
week, as an additional upper low drops south into the Ohio
Valley region by late Sunday absorbing remnants of low over
Strengthening southeast flow Saturday into Sunday will result in
decent QPF along the higher terrain, along with gusty winds.
There is some indication starting in the models of lower QPF
occurring in downslope favored regions of the lowlands during
this time period, and suspect this trend will continue to be
fine tuned in future runs. However, as the low begins to weaken
particularly on Sunday, and with upper low dropping south into
the area, will see a greater westward expansion of
precipitation, and overall lighter winds.
Low should finally kick out sometime early/middle of next week,
but timing on this remains uncertain.
At this time, mountains/southwest VA look to receive the highest
qpf amounts, with greater amounts east of our CWA. Period will
continue to need to be monitored for potential hydro impacts,
mainly due to the duration of rainfall, but impacts remain
uncertain at this point.
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 736 PM Wednesday...
Satellite imagery shows how a low to mid level cloud deck
erodes as they move over WV this evening. However, clouds are
expected to develop again tonight, as moisture advection
continues from the Great Lakes, and an upper level trough
continues to provide some forcing into our area overnight
tonight. H850 winds will be 15 to 20 knots overnight. These
clouds and winds will likely suppress dense fog formation if
they materialize. Otherwise, dense fog will be possible along
the most protected river valleys.
Therefore, coded VFR/IFR ceilings under low stratus at EKN, CKB,
BKW, and CRW developing by 08Z tonight. These low clouds will likely
last few hours after sunrise before mixing out by mid morning,
leading to widespread VFR conditions prevailing on Thursday.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY...
FORECAST CONFIDENCE: Low.
ALTERNATE SCENARIOS: Timing and location of low status or fog
may vary from forecast. IFR cloud deck timing and location may
vary from forecast.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
EDT 1HRLY 17 18 19 20 21 22 23 00 01 02 03 04
CRW CONSISTENCY H H H H H H H H H H H L
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H M M M M H M M H H H
PKB CONSISTENCY M H H H H H H H H H M M
CKB CONSISTENCY H H H H M H H H H M M M
AFTER 00Z FRIDAY...
IFR conditions possible in fog Friday morning.
Area Forecast Discussion
National Weather Service Tucson AZ
117 PM MST Wed Sep 28 2022
.SYNOPSIS...Scattered afternoon and evening showers and
thunderstorms are expected across parts of southern Arizona
through Friday. These are expected primarily from Tucson south and
west and over the White Mountains. Temperatures slide back a few
degrees by the end of the week.
.DISCUSSION...Thunderstorms and showers have developed in the
early afternoon for the Catalina Foothills and areas near HWY 79
in Pinal County. 19Z Mesoanalysis depicts better CAPE in Tucson to
the northwest than areas south and west of Tucson. Plus, there is
decent upper level divergence to help drive thunderstorm
development. The latest 18Z HRRR run seems to fair better over the
course of the morning as it captured the storm development in
Pinal County, but failed to pick out the Tucson storms. Not all
bad, the region just needs a little more daytime heating to
create better energy for storm development, especially west and
south of Tucson. As storms develop, they can last into the early
evening and bring locally heavy rainfall and strong gusty winds.
Tomorrow and through the weekend, a trough over the Pacific
Northwest will continue into the intermountain region to bring
about a change in weather. What a great way to end the monsoon
season for Southeast Arizona. The trough will start to bring
temperatures back down to near seasonal normals through the
weekend. The PWATs will continue to drop each day, however the
International Border and the White Mountains can expect to see
daily chances for thunderstorms through the weekend.
.AVIATION...Valid through 30/00z.
Isolated/scattered SHRA/-TSRA expected for the rest of the
afternoon through 29/04Z, mainly Tucson west and south.
SHRA/-TSRA returns after 29/20Z south and west of Tucson. SCT
clouds around 7-12k ft agl with BKN/OVC 20k ft AGL through the
rest of the period. SFC winds E-SE at 8-13 kts through the
afternoon with the occasional strong gusts from any TSRA. Aviation
discussion not updated for TAF amendments.
.FIRE WEATHER...Scattered afternoon and evening showers and
thunderstorms are expected through Friday, generally from the Tucson
south and west and over the Mogollon Rim country. The main threat
from the storms besides lightning will be strong and gusty
outflow winds. There will still be some SE/E morning and afternoon
breezes, but winds lighten by Thursday.
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