Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/18/23
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
923 PM EDT Sun Sep 17 2023
.SYNOPSIS...
A trough slowly moves east this afternoon into Monday, pushing a
cold front through the area and resulting in widespread showers
through tonight. Showers end by Monday afternoon with high pressure
building in. High pressure dominates the weather through late week
before a coastal low pushes moisture into the area Friday into
Saturday.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 920 PM EDT Sunday...
Early evening upper analysis reveals a potent mid-level trough
digging SE across the TN River Valley. The trough continues to
move E overnight, before ejecting northeast over the Mid-
Atlantic and northeast through Monday. At the surface, a few
weak areas of low pressure were noted across the mid-Atlantic
coast into the southeast early this evening. To the north, an
elongated area of weak low pressure was noted over SE PA, with
a cold front just NW of the local area. To the south, deepening
surface low pressure was noted over the Pee Dee/coastal plain
region of NE SC, and will slowly slip NE along the NC coast
overnight. This low has also served to cut off some of the
moisture for most of our area this evening, which has kept most
of the showers across the piedmont thus far.
Expecting 40-60 kt jetlet to provide ample forcing for ascent
to allow for more widespread storms to develop over the next few
hours. Given weak storm motions, also expect storms to congeal
into a narrow line and lift E-NE across eastern VA just east of
the I-95 corridor toward the peninsula and eventually the
eastern shore late tonight. Meanwhile, the warm front briefly
lifts across areas along the Albemarle Sound overnight, before
the training cold front pushes to the coast. Some modest
elevated instability will likely lift up across this area, but
the best kinematics/deep layer shear remain to our SE and
offshore. Thus, while a few rumbles of thunder cannot be ruled
out over coastal NE NC, not expecting much in the way of strong
to severe storms over our area, but will continue to monitor.
As PWATs increase to 1.5-2.0" ahead of the front tonight, some
pockets of briefly heavy rainfall are possible. QPF generally
remains 0.5-1.0" with locally higher totals expected in a line
extending from Mecklenburg NE through Westmoreland (including
Richmond and the Tri-Cities). Given dry antecedent conditions,
do not anticipate any significant issues from flooding. However,
cannot rule out isolated instances mainly in urban/poor
drainage areas. Finally, do expect some pockets of fog late
tonight over far western sections, as rain ends late tonight
west of I-95 before drier air arrives. The US-15 corridor from
Louisa to Farmville is favored by past few HRRR runs for fog
development, and will continue to reflect this potential in the
digital database.
Overnight lows in the upper 50s W to upper 60s E near the coast
with most areas in the lower 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
As of 345 PM EDT Sunday...
The cold front pushes through E portions of the FA Mon morning with
high pressure building in from the W. As such, showers over the
Eastern Shore Mon morning taper off by the early afternoon with
clear skies expected by the afternoon. Highs Mon in the upper 70s to
around 80F expected given sunny skies and downsloping winds allowing
for dew points to mix out into the mid 50s. High pressure centers
over the area Tues into Wed with mostly sunny skies and highs in the
upper 70s to lower 80s (Wed will be the hotter day with most areas
in the lower 80s). Lows in the low-mid 50s inland Mon night, mid 50s
inland and lower 60s along the coast Tues night, and mid-upper 50s
inland and low-mid 60s along the coast Wed night.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 345 PM EDT Sunday...
High pressure moves into New England by Thurs and remains centered
there through the weekend. This will result in dry weather
continuing through late week. Meanwhile, a coastal low is expected
to develop off the SE coast by Fri. Models diverge quite a bit with
where it will go from there, but the general trend is for the low to
move NE just off the coast through the weekend, enhancing the
pressure gradient between it and the high to the north. This would
result in unsettled weather with shower chances beginning Fri
afternoon and continuing through Sun night, a CAD situation inland
with much cooler temps in the Piedmont versus along the coast, and
breezy NE winds along the coast with winds 15-20 mph with gusts 25-
30 mph.
Highs in the upper 70s to lower 80s Thurs, upper 70s Fri, upper 60s
W to upper 70s along the coast Sat, and lower 70s W to lower 80s
along the coast Sun. Lows in the upper 50s inland to mid 60s along
the coast Thurs night, upper 50s W to upper 60s E Fri night,
and upper 50s to around 60F W to upper 60s E Sat and Sun nights.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 835 PM EDT Sunday...
Mainly VFR conditions to begin the 00z TAF period. Still
expecting rapidly deteriorating conditions in the next few
hours, as a cold front pushes across the region. Conditions
lower to MVFR through 04-06z this evening and eventually IFR
late tonight (mainly after 05-08z), with short-lived LIFR
conditions possible between 07-10z. IFR VIS will also be
possible, due both to rain and also with fog at RIC behind the
front toward morning. Showers should taper off from W to E late
tonight into Mon morning, potentially lingering over the Eastern
Shore until late Mon morning to early Mon afternoon. A return
to VFR conditions is expected by Mon afternoon as clouds clear.
Outlook: Conditions improve from W to E Mon aftn and evening.
High pressure and dry conditions return early next week.
&&
.MARINE...
As of 345 PM EDT Sunday...
Afternoon analysis shows surface high pressure now well offshore
with a series of surface lows/fronts to the NW. Aloft, a trough
continues to dig southward over the Ohio Valley with a strong ridge
over the SW CONUS. Winds today have generally been S at 10-15 kt
with a few gusts to 20 kt. Waves in the Ches Bay are 1-2 ft with
seas around 3 ft.
Guidance shows winds hovering right on the cusp of Small Craft
thresholds in the Ches Bay late this afternoon through late evening.
Hi-res models (HRRR and RAP especially) show a period of marginal
SCA conditions in the bay this evening but will hold off on any
headlines with little support from local wind probabilities (20-40%
chance of sustained winds 18+ kt). Models also continue to differ
regarding the placement and strength of secondary low formation
near/off the NC coast tonight. The NAM is the strongest/farther
north solution and continues to show 4-6mb of deepening in ~6 hours
prior to sunrise with the remaining models either weaker or farther
SE with the low. That said, a brief period of SCA conditions near
and south of the VA/NC border is possible Monday morning before a
cold front moves through the region. Winds become NNW ~15 kt behind
the boundary with some potential for brief SCA conditions over our
northern Ches Bay zones with favorable funneling of NW winds. Benign
conditions return late Monday night and continue through mid week as
high pressure settles over the region. A period of increasing NE
winds sets up between a coastal trough off the SC/GA coast and
strong high pressure over New England, resulting in likely SCA
conditions late week into the weekend. Seas will generally be 2-4 ft
this week but increase quickly from Thursday onward as NE winds
increase.
There is a moderate rip current risk at all area beaches on
Monday.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...RMM
NEAR TERM...MAM/RMM
SHORT TERM...RMM
LONG TERM...RMM
AVIATION...MAM/RMM
MARINE...RHR
Area Forecast Discussion
National Weather Service La Crosse WI
1100 PM CDT Sun Sep 17 2023
.DISCUSSION...(This evening through Sunday)
Issued at 328 PM CDT Sun Sep 17 2023
Key Messages:
- Medium confidence of light precipitation across parts of
northeast Iowa and southwest Wisconsin late Monday night
(30-50% chance).
- Above-normal temperatures by mid-week with high temperature
in the upper 70s to low 80s Wednesday-Friday.
PATCHY FROST IN CENTRAL WISCONSIN TONIGHT:
With high pressure overhead, calm and clear conditions will help
maximize radiational cooling tonight. This will result in
temperatures cooling into the 40s across most of the region and into
the 30s in the sandy soil areas of Central Wisconsin. If low
temperatures do indeed reach the mid 30s, patchy frost is likely.
RAIN CHANCES RETURN MONDAY NIGHT:
As high pressure pushes off to the east Monday night, a shortwave
trough is progged to slide over the southern half of the forecast
area bringing the next chance for precipitation to the region. Model
soundings exhibit little to no CAPE with the timing of the wave
targeting the overnight hours, but a rumble of thunder or two cannot
be ruled out. GEFS and EPS members are in good agreement that light
rain < 0.25" is likely given very few members of the EPS or GEFS
producing more than 0.2 or 0.3". Some of the CAMS such as the ARW,
RAP, and HRRR bring most of the coverage south of the area across
central and southeast Iowa so there is still room for forecast
refinements.
WARMER BY MID-WEEK:
An upper-level ridge builds over the Upper Mississippi Valley
bringing above-normal temperatures in the upper 70s to low 80s
Wednesday through Friday. There are key differences in the
deterministic models by next weekend highlighting the lower
predictability beyond Friday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1111 PM CDT Sun Sep 17 2023
Similar to previous forecasts, concern for valley fog at KLSE
remains primary concern. Dewpoint depressions at 04Z are only a
few degrees, suggesting saturation possible with clear skies
allowing surface cooling to continue. Ongoing difficulty is off
deck winds. If fog does develop, confidence for dense, widespread
is low. Radar wind profilers upstream through northern Wisconsin
show 20 kt north-northeast winds at 850 mb and 15 kts at 925mb.
Northerly wind expected to continue, albeit limited cold air
advection, potentially abating surface wind gusts. Very limited
for any impacts at KRST Monday morning.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...KAA
AVIATION...JAR
Area Forecast Discussion
National Weather Service Quad Cities IA IL
634 PM CDT Sun Sep 17 2023
...00Z AVIATION UPDATE...
.SHORT TERM...(This evening through Monday)
Issued at 100 PM CDT Sun Sep 17 2023
Key messages:
1. Cooler tonight with some fog possible.
2. Quiet day expected on Monday.
Discussion:
Low pressure over Lake Michigan was leading to showers across
Illinois. Low level clouds associated with this low moved into
the area this morning. They have since begun to break up leading
to sct to bkn deck of clouds. It is possible that some weak
showers could form later this afternoon due to steep llvl lapse
rates. Have decided to leave from forecast as confidence in
occurrence is low.
Tonight, a good setup for radiative cooling with clear skies and
the high pressure directly overhead. Guidance has fog developing
along and east of the Mississippi River. Some guidance has
widespread dense fog. Think this will be possible, as such have
added it to the HWO. Do not have the confidence to go with a DFA
at this time. Later shifts may need to do this.
Tomorrow looks a quiet and nice day for the area.
.LONG TERM...(Monday night through Sunday)
Issued at 100 PM CDT Sun Sep 17 2023
Key messages:
1. Pattern change to start the period with chances for rain Tuesday.
2. Additional chances for rain/storms with warmer temperatures
expected through the rest of the long term period.
Discussion:
To start the period, a ridge will be in place across the upper
Mississippi River valley while a weak shortwave moves south of the
base of the ridge and into our area. In response to this wave, WAA
occurs and a decent (40-50kt) LLJ moves into western Iowa around 06z
Tuesday. This jet and WAA is forecast to slowly move east through
the overnight. Bringing with it, a chance for rain and storms. In
the wake of this wave, the ridge amplifies. Waves through the flow
underneath the ridge may lead to showers and storms through the
week. Late in the week, a closed low over FL forms. Late in the
period, another closed low forms west of the area and moves towards
us. The forecast for the middle part of the week into the weekend
is rather uncertain. Guidance always struggles with closed lows with
complex flow. All deterministic models have warmer air through the
week and a closed low for next weekend. The location and timing of
this low is different leading to a low confidence forecast.
As far as storms/showers go later in the week, there isn`t a strong
signal for severe convection based on the Colorado State machine-
learning severe probabilities. NBM probabilities of rainfall give
pretty low values for rainfall over a tenth of an inch for each day,
so while we will have some periodic chances for rain, it doesn`t
appear likely for a decent rainfall at this time.
Tuesday night, the better forcing for ascent looks to be across
western and central IA. Synoptic models have the rain and showers
in that area. However, the CAMs have convection further east. This
looks tied to the RAP which has the LLJ further south and east.
Until the synoptic models move the forcing, I think the location for
the storms is better forecast by the synoptic models, but the mode
by the CAMs. As such, imagine the CAM solutions where the synoptic
models have the forcing. The activity should form across western
and central IA. Some of this activity could make its way into the
western CWA near daybreak. MUCAPE looks low, but with the convergence
on the nose of the jet, could see some thunder with the showers.
CAMs are depicting some cellular returns as well. At this time it
looks like most areas will see some rain, and some places may see up
to half an inch of rain in stronger cells.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 630 PM CDT Sun Sep 17 2023
Radiational fog is expected to develop after 07z, mainly impacting
the terminals near the Mississippi River and especially further
eastward through Illinois and southern Wisconsin within a surface
ridge axis. Have hit the fog the hardest at KMLI and KBRL where
better low level moisture resides aided by recent rainfall.
For now have gone with IFR visibilities at both sites, but there is
a chance for LIFR/VLIFR. Have gone with MVFR for now at KDBQ, which
didn`t see as much rain, but there is a chance for lower conditions.
Left out fog at KCID, which saw minimal rainfall and currently have
the greatest temperature/dew point spreads. Kept fog mention until
14-15z, as it`s getting to be that time of year now with the later
sunrises we`re seeing fog hang around longer. Mid morning conditions
should return to VFR with cumulus few-Sct035-045 by afternoon.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHORT TERM...Gibbs
LONG TERM...Gibbs/Schultz
AVIATION...McClure
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
647 PM CDT Sun Sep 17 2023
...Aviation Update...
.DISCUSSION...(This evening through Sunday)
Issued at 241 PM CDT Sun Sep 17 2023
Key Messages:
* Just a little bit of haze from Canadian wildfires this
afternoon. Should improve this evening and move out entirely on
Monday.
* A few thunderstorms Monday evening. Coverage will be spotty,
but a couple strong storms are possible.
* Only low chances for thunderstorms Tues/Wed. Majority stays
dry.
* Better chances for rain/storms arrive Thursday night through
weekend.
Details:
A little bit of haze is apparent on satellite imagery and surface
observations over the eastern Half of Nebraska. HRRR and RAP
smoke models are not initializing the magnitude of the smoke
concentration very well, but the areal extent is reasonable. This
would indicate improving conditions due to the continued southerly
winds this evening into Monday.
Monday will be a bit breezier ahead of an approaching shortwave
and surface trough of low pressure. Many locations will approach
90 degrees for afternoon highs. This shortwave will then give us a
chance for thunderstorms through the evening hours. Coverage of
storms looks spotty, at best, and most spots will miss out. That
said, we cannot rule out a few storms on the stronger side, but
lack of shear should preclude any organized severe threat.
Tuesday and Wednesday will feature spotty chances for rain and
thunderstorms, but coverage may be even more limited than on
Monday. Better chances for rain and thunderstorms arrive Thursday
night and last into the weekend as a deeper upper low moves across
the central/northern Plains. That said, there is still some
disagreement amongst global deterministic models and ensembles,
with the Euro/EPS being more optimistic with QPF and coverage than
the GFS/GEFS.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday)
Issued at 645 PM CDT Sun Sep 17 2023
Tonight: VFR expected, though GRI could still have some minor VSBY
reductions from smoke continue overnight. Certainly, appears the
worst is shifting N and E. Winds will be SE-S 6-10kt. Can`t
completely rule out some marginal low level wind shear at EAR
after midnight, but will continue to monitor and include in next
TAF, if needed. Confidence: High.
Monday: VFR conditions and a bit brzy. Expect Srly winds 12-15kt,
with gusts around 20kt, from midday through the aftn. Confidence:
High.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Mangels
AVIATION...Thies
Area Forecast Discussion
National Weather Service Goodland KS
430 PM MDT Sun Sep 17 2023
.SHORT TERM...(This evening through Tuesday)
Issued at 110 PM MDT Sun Sep 17 2023
Ridging across the the Rockies is present on latest RAP analysis
under clear skies. A surface trough is slowly nosing into the
area from the NW, overall flow with the trough is rather weak so
not anticipating any breezy or gusty winds through the afternoon.
The pressure gradient with the trough does tighten some overnight
bringing the potential for some 15-20 knot sustained winds over
the northeastern portion of the CWA. I have also lowered
temperatures some overnight tonight along with some lower dew
points based on some of the better performing dew point guidance
from last night. Some radiational cooling concerns are possible
mainly west of Highway 25 as the upper level clouds from the
Rockies doesn`t appear to be as prevalent as seen on the 12Z run
of the HREF.
Monday, the surface trough moves east of the area as the ridging
breaks down. Will be watching for a plume of moisture advection
resulting in a developing dryline across the area. A weak
shortwave along with some upper level moisture moves across the
area leading to the potential for some showers and thunderstorms
to develop along the dryline during the afternoon hours. Overall
convective parameters look relatively the same regarding
CAPE,shear and lapse rates as what I was seeing yesterday so can`t
completely rule out a low end severe storm. For pops went with a
blend of the previous forecast, NAMNEST and WRF-NSSL as those have
been the most consistent with the convection potential, which I
feel is important as soundings show low 90 temperatures as the
convection temperature which should help overcome any potential
capping issues that may be in place. Recent runs of guidance show
a few hours on near critical to spotty critical fire weather
conditions developing across Yuma county Monday afternoon.
Overall flow is overall impressive but assuming full mixing can
occur there can be some occurrence of 25-30 mph wind gusts along
with RH values in the mid teens.
Tuesday, the trend to a more active pattern begins to take shape. A
dry line will be present although not as sharp as Monday`s will be
present so will be watching for additional showers and storms over
the east. The main change from yesterday is a bit stronger of wave
moving across the Rockies which is anticipated to bring
additional rain chances to the western portions of the area.
Guidance is all over the place on the coverage of showers and
storms so am opting to leave silent pops for the majority of the
area with the exception being Graham and portions of Gove where
the relative better potential for severe weather looks to occur.
.LONG TERM...(Wednesday through Sunday)
Issued at 204 PM MDT Sun Sep 17 2023
Main focus for this part of the forecast continues to be how the
closed low over the Pacific Northwest will develop, which will
impact the weather toward the end of the week.
Zonal flow over the Central Plains will transition to southwest flow
as the closed low deepens over the Pacific northwest. This will
cause temperatures to cool slightly through the week. Ahead of the
closed low there may be low chances for rainfall over the eastern
and northern part of the forecast area as weak upper level short
wave troughs move through.
Looking at the GEFS and ECMWF members, confidence is on the low side
regarding rainfall prior to the closed low moving through at the end
of the work week. The GEFS has even fewer members placing rainfall
over the forecast area than what was seen yesterday. The ECMWF has
very few members as well showing rain potential for the forecast
area.
Toward Friday models have slowed down the eastward progression of
the closed low, having it deepen further west than what was shown
yesterday. The closed low is also shifted to the south. Unless the
closed low becomes an open wave, am still thinking the movement to
the east is too fast.
When the trough moves east it will have a dry line accompany it. The
dry line will form over the forecast area; more likely the eastern
third. The setup continues to be favorable for severe weather.
However, am still skeptical there will be severe weather in the
forecast area unless the closed low/trough ends up being over or
southwest of the forecast area. Otherwise we will more than likely
be west of the dry line and have critical fire weather conditions.
Looking at the blowing dust parameters, there certainly could be
blowing dust. However if this does occur it will likely be near
bare fields/ground.
Behind the trough a cold front will sweep through the forecast area.
Behind the front northerly winds may be breezy. The breezy winds
may last through Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 430 PM MDT Sun Sep 17 2023
For KGLD, VFR conditions through the forecast period. Winds,
south around 10-15kts through 12z Monday, then veering southwest
5-10kts, then northwest by 17z.
For KMCK, VFR conditions through the forecast period. Winds,
southeast around 10kts, then shifting southwest around 10-15kts by
05z Monday. LLWS 05z-12z Monday 210@40kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...Trigg
LONG TERM...JTL
AVIATION...JN
Area Forecast Discussion
National Weather Service Green Bay WI
1046 PM CDT Sun Sep 17 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 224 PM CDT Sun Sep 17 2023
The latest RAP analysis and satellite/radar imagery show high
pressure centered over the northern Mississippi Valley. North
winds ahead of the high augmented by moisture fluxes off Lake
Superior have contributed to widespread convective clouds
developing today. The clouds have kept temps cool and only in the
50s over north-central WI this afternoon. As the high settles over
the area, dense ground fog and frost potential are the main
forecast concerns.
Synopsis: High pressure will become centered across the region
tonight and shift to the central Great Lakes on Monday.
Sky & Weather: High pressure will promote good radiational
conditions tonight. Most uncertainty revolves around cloud cover.
But as the low level ridge axis shifts to eastern Wisconsin by 7
am Monday, wind trajectories become light southerly and think
there will be sufficient time for clearing skies and rapidly
falling temps. Will remain aggressive with lowering temps with mid
30s possible over north-central WI by morning. Patchy to areas of
frost and also dense ground fog appear possible overnight into
early Monday morning.
Once the ground fog burns off in the morning, scattered fair
weather clouds are expected to develop with the heat of the day
but no precip is expected.
Temperatures: Chilly temps are forecast tonight with lows ranging
from the mid 30s to upper 40s across the region.
On Monday, warmer highs in the middle 60s to low 70s are forecast.
Impacts: After coordinating with surrounding offices, will issue
an SPS which will cover the fog and frost potential. Anyone with
cold sensitive plants are urged to cover or bring the plants
inside over north-central Wisconsin tonight. Locally dense ground
fog will also restrict visibilities for the Monday morning
commute.
.LONG TERM...Monday Night Through Sunday
Issued at 224 PM CDT Sun Sep 17 2023
High pressure will shift slowly east of the region Monday night
into Tuesday night, with developing south flow resulting in a
gradual warmup into the midweek period. Above normal temperatures
are anticipated for the mid to late part of the week.
Precipitation chances are tough to decipher at this time, so will
not make any significant changes to the model blended forecast.
Warm air advection and a short-wave trough may bring a small
chance of showers to our southwest/south counties late Monday
night into Tuesday, and a warm front could keep a small chance
across C/EC WI into Tuesday night. A building upper level ridge
will commence mid-week, but a warm frontal passage could keep a
small chance of precipitation in the forecast Wednesday into
Wednesday evening. Suspect there will be a dry period for the
end of the work week, as the warm front shifts north and upper
level ridging persists. For next weekend, models all show a
significant surface/upper low developing over the Plains, but
the location varies considerably north to south. Precipitation
chances will hinge on how quickly this system shifts east, and
the strength of low-level dry E-NE flow out of an eastern
Canadian high pressure system.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1046 PM CDT Sun Sep 17 2023
MVFR and low-end VFR clouds continue to erode late this evening
over far northern/eastern WI. Low clouds and areas of dense fog
will develop over central and northern WI after midnight into
Monday morning. Highest chances on the SREF/HREF are at RHI so
will continue with VLIFR conditions there. Confidence is lower at
AUW/CWA, but LIFR/VLIFR are possible. Lower chances for any
impactful fog at GRB/ATW/MTW, but a period of lower VSBYs are
possible overnight.
The fog will burn off by around 15z Monday morning, then look for
VFR conditions the rest of the day, with some daytime cu expected
to develop as enough moisture around 5000 ft will remain in
place. Some patchy fog will be possible Monday night, especially
over far northeast WI, mainly after 06z.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......Bersch
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
839 PM EDT Sun Sep 17 2023
.Forecast Update...
Issued at 839 PM EDT Sun Sep 17 2023
Convection continues to wane with loss of diabatic surface heating
this evening. Lower tropospheric moisture is still present to a
significant enough degree for some stratocumulus to remain. It does
appear this will decrease sufficiently for portions of central
Indiana to experience enough radiative cooling for some fog to form
early Monday. This doesn`t appear to be a widespread/dense fog
scenario. Previous forecast looks good and only minor adjustments
are needed.
&&
.Short Term...(This evening through Monday)
Issued at 259 PM EDT Sun Sep 17 2023
- Isolated showers and clouds exiting Tonight
- Partly cloudy and Warmer on Monday
Surface analysis this morning shows a broad, disorganized area of
trough of low pressure stretching across Indiana, Ohio, and southern
Ontario. More organized high pressure was found over MN and the
northern plains. Aloft an area of low pressure was seen over NW
Indiana, showing the classic comma style cloud signature with clouds
stretching south across Indiana. Radar shows precipitation was
mainly focused limited to the comma head area, near Chicago but a
few showers were starting to rotate into NW Central Indiana. Water
Vapor shows the upper pattern showed strong ridging in place over
the Rockies with a deep trough in place over Ontario, the Great
Lakes IL and Indiana.
Tonight -
Models tonight show a change in the upper pattern. The trough over
the Great Lakes and Ohio valley is expected to depart tonight. This
will allow the strong ridging aloft over the Rockies to build east
into Indiana tonight. Strong subsidence is expected on the lee side
of the ridge across Indiana as the night progresses. Thus clouds and
the very isolated showers across the area are expected to dissipate
as they depart this evening and as heating and associated
instability is lost. Thus will likely need to include some pops
during the late afternoon hours and early evening hours. HRRR is on
board with this, showing precipitation across the forecast area by
03Z.
Overnight clearing will be expected as surface high pressure over
the plains builds across Indiana from the west. Fog is not expected
as a moderate surface pressure gradient is expected, allowing winds
to provide weak mixing. However, dew point depressions of less than
1-2F may allow for some stratus formation. Overnight lows should be
in the lower 50s.
Monday -
Pleasant weather is expected on Monday. With strong ridging in
place aloft west of Central Indiana, subsidence predominates across
our area. Mid levels show dry air through the day as forecast
soundings show a very dry column. Meanwhile at the surface, strong
high pressure is expected to push into Indiana. Forecast soundings
suggest some scattered CU will be possible, so partly cloudy to
mostly sunny will work fine. Expect highs in the upper 70s to near
80.
&&
.Long Term...(Monday night through Sunday)
Issued at 259 PM EDT Sun Sep 17 2023
* Pleasant and dry weather expected throughout most if not all of
the long term and potentially beyond.
Long term guidance continues to depict increasing influence of upper
level and particularly surface ridging throughout most of the long
term period. There are some hints that weak disturbances may impinge
upon the region late in the week into next weekend, but the
aforementioned ridging, a lack of any substantial moisture return,
and antecedent dry ground (drying more each day), even with today`s
spotty showers, will be a significant factor in suppressing
precipitation chances. Have removed some of the spotty slight
chances toward the end of the period.
As heights build and southerly low level flow returns, expect highs
to return to the upper 70s to low/mid 80s across the area each day
save for Tuesday, which will likely be in the mid 70s to low 80s.
Diurnal ranges of 20-25 degrees are likely, given the dry
conditions, and have made minor min temp adjustments, as well as
blending in some 10th percentile NBM dewpoints to better reflect
expected progression both in cooler overnights and afternoon mixing
impacting readings. While critical fire weather conditions do not
appear particularly likely, low RH values and dry ground will merit
some monitoring as we go through the week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 705 PM EDT Sun Sep 17 2023
Impacts:
* Low probability of fog early Monday
Discussion:
VFR conditions should prevail with the only exception being a low
chance of fog and associated visibility reductions. Cooler air mass
will not be substantially drier, and as cumulus field diminishes
later this evening and gradient relaxes, radiative conditions might
be enough for fog formation across portions of central Indiana.
Isolated showers that are still present as of this writing should
continue to diminish as diabatic surface heating wanes.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...BRB
Short Term...Puma
Long Term...Nield
Aviation...BRB
Area Forecast Discussion
National Weather Service Tucson AZ
143 PM MST Sun Sep 17 2023
.SYNOPSIS...Slightly above normal high temperatures will continue
through Monday then cool to near normal by mid week. While dry
weather will prevail, there will be a chance for showers and
thunderstorms east of Tucson and near the New Mexico line Monday.
&&
.DISCUSSION...Tucson is once again flirting with another 100
degree day with as of 1:30 pm MST, Tucson International Airport
has reached 99 degrees Fahrenheit. As for storms, currently there
are building cumulus over the higher elevations with a few
thunderstorms forming along the Mogollon Rim and along the
Arizona and New Mexico border. The area for favorable convection
is areas east of Tucson, due to the 3 thunderstorm ingredients of
moisture, instability and lift being prevalent. As mentioned in
the previous discussion, there is a quasi-dryline, basically
meaning that there is an area of dry and moist air, with dewpoints
in the mid 50s to low 60s areas east of Tucson and mid 30s to mid
40s Tucson westward. As for instability, the latest Rapid Refresh
Model (RAP) from SPC shows the best area for Mixed Level CAPE of
500-1000 J/kg highlighted in Graham, Greenlee, and eastern
portions of Cochise and Pinal counties. The RAP model also shows
the best area for lift is shown on the 300 mb height chart
highlights the same areas as previously mentioned for upper level
divergence that would help to sustain thunderstorm life by
allowing for any potential updrafts to keep up with the lifting
air by moving it out faster. All this to say, the best storm
chances are areas east of Tucson for this afternoon and evening.
Looking ahead, the upper level high will begin to shift and
reconsolidate to the south over Baja and northwestern Mexico
before moving slightly eastward allowing for a deepening trough
that is originating from the Pacific NW to move through the area
Thursday afternoon. This system will tighten the pressure gradient
and bring some afternoon breeziness as well as bringing some
cooler temperatures at the end of the work week and into the
weekend. The afternoon breeziness, drier weather, and low RHs will
heighten fire weather concerns for Thursday, more in the fire
weather discussion.
&&
.AVIATION...Valid through 19/00Z.
FEW-SCT clouds around 15k ft MSL KTUS eastward with ISOLD -SHRA/-TSRA
E of KSOW-KSAD-KDUG through sunset. SKC overnight with FEW-SCT
clouds around 15K ft MSL again Monday afternoon near the New
Mexico line and ISOLD -SHRA/-TSRA NE of KSAD. SFC winds SLY
10-12kts with gusts near 20 kts through sunset, then SWLY 10-15
kts with gusts 18- 23 kts Monday afternoon. Otherwise, SFC winds
terrain driven less than 10 kts. Aviation discussion not updated
for TAF amendments.
&&
.FIRE WEATHER...Dry weather will prevail through the period with
Min RH values mainly 10-15 percent from Tucson west, 15-20 percent
in eastern valleys and 20-30 percent over the higher elevations.
There will be just enough moisture for a few thunderstorms near the
NM line into early evening, near the Rim Monday afternoon and near
the NM line again Thursday. 20-foot winds each afternoon will
generally be SWLY with gustiness due to daytime heating. A weather
system passing to our north mid week will cause an uptick in winds
speeds. Right now Thursday is shaping up to be the breeziest with
gusts of 30 to 35 mph in some locations. This could cause critical
fire weather criteria to be reached for an hour or two.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Public...Tetrault
Aviation...Drozd
Fire Weather....Drozd
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