Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/03/19
Area Forecast Discussion
National Weather Service State College PA
1049 PM EDT Wed Oct 2 2019
A cold front will drift south through the area tonight. The
front will briefly lift back to the north Thursday. A stronger
cold front will usher in a stark change of airmass for the end
of the week. Temperatures will moderate slowly through the
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The cold front has settled into far southern PA and is very
close to the Mason-Dixon line as of 10PM. The front will
likely not make it much south of the border before beginning to
lift back north as a warm front Thursday.
The HRRR continues to show areas of rain sliding ESE across the
CWA overnight so I continued with the high POPs though the QPF
will not be terribly heavy.
Min temps will vary from the mid-upper 40s across the northern
mountains to the low-mid 60s across the southern tier.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
The frontal boundary will meander back to the north into central
PA for a 5-10 hour period Thursday as a wave of low pressure
slides east across central PA.
MU Capes will increase to between 1000-1500 j/kg across portions
of our western mtns zones - west of Interstate 99 Thursday
afternoon, while cool air damming and periods of light to
moderate stratiform rain keep capes minimal to non-existent
throughout the Susq Valley and points east.
Near and just to the NE of the wavy/quasi-stnry front will be
some hefty, low-level (0-1 km) storm relative helicity of
250-350 m2/s2. Although SPC paints just a MRGL risk of severe
TSRA due to the aforementioned CAPE limitation, the strong llvl
shear along the boundary will lead to a rare mention of a few
weak tornadoes with this lower end category of overall SVR
Max temps Thursday will exhibit a near 25 deg spread from NE to
SW across our CWA, with mid 50s across the high terrain of
Sullivan County to near 80F in valleys of southern Somerset
county. High temps in the 60s will be prevalent throughout the
majority of the forecast area Thursday.
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Northerly flow will continue to drag cooler air into the area
Thursday night into Friday. A few lingering showers are possible
across northern PA into early Friday. Otherwise, building high
pressure over the Great Lakes will bring improving conditions.
A chilly Friday night is in store, as the sky clears and winds
diminish. Patchy frost is likely across northern PA, and is
possible in some of the normally chillier spots farther south.
After a chilly start, Saturday will be a seasonably cool day
with a good deal of sunshine.
Flow will turn southerly Saturday night into Sunday, as high
pressure slides off the New England coast and another frontal
boundary approaches. Scattered showers are expected to develop
as the day progresses on Sunday.
The frontal boundary will slow down as it crosses the area on
Monday, and it may be accompanied by a period of steady
rainfall. Behind the front, another shot of below-normal
temperatures is expected for the middle of next week.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
As a cold front sags southward across southern PA tonight into
Thursday, IFR conditions will develop and periods of rain will
occur for much of the region and most of the time (esp across
the NE half of PA) later tonight and Thursday, with some low-
moderate convective instability leading to scattered TSRA form
the Western Mtns to the Ohio border.
Thu...Rain/low cigs possible, especially northern Pa.
Fri...Gusty NW winds. AM low cigs possible N Mtns.
Sat...Patchy AM fog possible.
Sun...Rain/low cigs possible NW half.
Mon...Morning showers SE half of PA, then slowly improving
conditions with areas of MVFR to IFR lingering over the Western
Mtns through the afternoon.
Harrisburg set a record with a high temperature of 93 degrees.
The old record was 87 set in 1927.
NEAR TERM...La Corte/Lambert
Area Forecast Discussion
National Weather Service Duluth MN
1008 PM CDT Wed Oct 2 2019
Issued at 1004 PM CDT Wed Oct 2 2019
Cancelled gale warning as obs have come down and model guidance
does not indicate any strengthening of the winds overnight. An
isolated thunderstorm or two are being observed on satellite
imagery under 100 J/kg of MUCAPE.
Decreased the dew points and temperatures across the Arrowhead as
obs are coming in colder than the forecast. This resulted in a
little more snow. After careful thought, decided not to issue any
winter weather headlines as impacts from this should be low -
mainly because road temperatures are in the mid 40`s and it will
take quite a bit of snow to overcome that to make for difficult
travel. Will cover threat with an SPS.
.SHORT TERM...(This evening through Thursday night)
Issued at 312 PM CDT Wed Oct 2 2019
Precipitation chances will continue to increase CWA wide this
evening as an inverted trough slides in from the Northern Plains.
The main concern is potential for accumulating snowfall along the
International Border tonight.
Initially, high pressure is building over southern Manitoba and
western Ontario while a somewhat stationary front is draped from the
Central Plains into the Central Great Lakes. A trough will lift from
the Intermountain West into the Northern Plains by this evening.
Models have been a bit slow in the development of the inverted
trough over the region, which is already evident per SPC
Mesoanalysis and with precipitation already spreading in. Accounted
for this by utilizing the latest HRRR and NMM guidance which are
more in line with reality. Highs today will top out in the mid 40s
along the North Shore of western Lake Superior, to the low 50s in
southern portions of northwest Wisconsin.
Precipitation is likely CWA wide overnight. Confidence at this point
in time is quite high CWA wide for QPF amounts with roughly 0.50 to
0.75 inches expected which is backed up by the latest SREF and GEFS
plumes. The uncertainty lies in the precipitation types mainly
across the International Border area and the Minnesota Iron Range.
The latest (09Z) SREF guidance shows a large spread especially at
INL with values ranging from 0 to 5 inches and no real clustering
around a solution. Locations further south and east across the Iron
Range show a range of 0 to 5.5 inches. There is bifurcation of
clustering around lower (0-2 inches) and higher amounts (3-5
inches). The lower solution is contingent on surface temperatures
remaining in the mid 30s while the higher solution is more likely
with colder surface temperatures. Expect surface temperatures to
remain mild as surface dew points should remain in the mid 30s,
which should keep temperatures in the mid 30s across most areas
overnight. Will need to keep a close eye on things because if drier
air works its way in then surface temperatures could cool into the
lower 30s and result in higher snowfall totals across the North.
Lows tonight range from the mid 30s across the north to the mid 40s
in southern portions of northwest Wisconsin.
The inverted trough will lift into Ontario and the central Great
Lakes on Thursday while high pressure builds into the Northern
Plains. Any rain/snow mix will come to an end early Thursday morning
and become all rain. Precipitation will end from southwest to
northeast across the majority of the CWA during the morning. Flow
aloft will shift to a northerly direction and bring lake effect rain
shower chances to much of the South Shore through the rest of the
day. Highs will generally be in the 40s across the region.
.LONG TERM...(Friday through Wednesday)
Issued at 312 PM CDT Wed Oct 2 2019
High pressure should lead to clearing skies Thursday night and it
will get cold. The exception will be along a portion of the South
Shore, mainly across northern Iron County. Northerly winds across
the relatively warmer water of Lake Superior should produce some
lake effect rain and snow showers over northern Iron County. We
do not expect much accumulation at this time as delta-T values are
not supportive and surface temperatures will remain above freezing.
Elsewhere, clouds should diminish overnight and we expect lows
from 25 to 30 over much of far northern Minnesota to the lower to
mid thirties elsewhere. A widespread frost should occur with a
freeze in spots as well. The only caveat is that clouds can be
stubborn to erode at times in the fall so if they hold on longer,
temperatures won`t get as cold.
The next chance for showers will arrive Friday night and continue
into Saturday as a longwave upper trough moves into the Northern
Plains then over Minnesota Saturday. There remains some
differences between the GFS and ECMWF with the strength of a
shortwave in the base of the trough, the ECMWF is stronger and a
bit slower. It also develops the surface low over Minnesota. There
will be a chance for showers and a few thunderstorms Friday night
into Saturday with chances diminishing but not ending Saturday
night. We included a mention of thunder despite limited
instability as forcing is quite strong. The upper trough will
remain over or near the Northland into Sunday and a chance for
showers will continue Saturday night into Sunday, especially over
northern Minnesota. Temperatures Friday through the weekend will
remain a few degrees below normal.
Most areas will be dry Monday into Wednesday as an area of high
pressure moves through the region. There will also be a slight
warming trend and by Wednesday, highs are expected in the upper
fifties to lower sixties.
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 636 PM CDT Wed Oct 2 2019
MVFR becoming more IFR as a system moves across the Northland
tonight and departs on Thursday. Snow will mix with rain near
KINL and there`s a low chance that there could be decent
accumulations - if more snow occurs vsbys will be lower there.
Gusty winds will occur through the evening near KDLH.
Issued at 1002 PM CDT Wed Oct 2 2019
Lake Superior was between high pressure over Manitoba and Ontario
and low pressure well off to the south this afternoon. As a
result, stronger east to northeast winds have developed. An area
of low pressure will move through the region tonight and the
stronger east/northeast winds will continue tonight. As the low
moves away from the region on Thursday, the wind will decrease and
back to northerly. It will take the waves a bit longer to subside
on Thursday and we will likely need to extend the Small Craft
Advisory from Chequamegon Bay to Saxon Harbor into Thursday
evening. We also will likely need a Small Craft Advisory for the
rest of the North Shore tonight into Thursday. High pressure will
bring in a period of lighter winds Thursday night into Friday.
.PRELIMINARY POINT TEMPS/POPS...
DLH 40 47 36 51 / 100 90 0 0
INL 34 44 30 53 / 100 90 0 0
BRD 40 47 36 54 / 100 40 0 0
HYR 43 48 35 54 / 100 60 10 0
ASX 43 48 37 56 / 100 90 10 0
LS...Small Craft Advisory until 4 PM CDT Thursday for LSZ121-140>147.
Small Craft Advisory until 10 PM CDT Thursday for LSZ148.
Area Forecast Discussion
National Weather Service Hastings NE
954 PM CDT Wed Oct 2 2019
...Short Term Update...
Issued at 953 PM CDT Wed Oct 2 2019
Regarding the overnight hours/Frost Advisory situation:
THE BOTTOM LINE:
Have added Greeley County to our going Frost Advisory (valid 3-9
AM Thursday), which now means we have 5 of our far northern /west-
central Nebraska counties included.
As outlined well by preceding day-shifter below, tonight`s frost
potential is not a "slam dunk", but is instead somewhat
marginal/uncertain in nature. That being said, we do not want to
"miss" the first first possible frost of the fall, so we are
erring on the side of caution, if anything.
Essentially, have maintained a mention of "patchy frost" and
issued/maintained the Advisory for all counties where widespread
lows as cold as 35-37 degrees are expected. Possible mitigating
factors that could work against frost formation include:
lingering pesky/at least scattered low clouds, and northerly
breezes that are not truly calm (perhaps remaining up in the 4-8
Whether or not any frost actually forms early Thurs AM in our
northern/western zones, one thing we are confident in is that we
will NOT see sub-freezing temps of 32-or-colder, so this is NOT a
true freeze situation.
.SHORT TERM...(This evening through Thursday)
Issued at 150 PM CDT Wed Oct 2 2019
Aloft: RAP tropopause analyses and aircraft wind data cont to
show a moderately-amplified longwave pattern. An anomalous 594 dm
subtropical high was over the Ern USA....centered over the TN Vly.
A trof remained over the W...with a low over MT/WY. This low will
move E along the US-Can border tonight and then begin to weaken N
of the GtLks tomorrow. In its wake...heights will rise over the
Plns with a low-amplitude shrtwv ridge developing. Meanwhile...the
next trof will move onshore in the W.
Surface: A strong quasi-stationary front extended from the Srn
GtLks acrs KS into CO...with a couple weak lows migrated E along
it. Strong high pres was over ON. One of these lows will become
dominant over IL/IN tonight...forcing the front into the Srn Plns.
Anticyclogenesis will occur over the Cntrl/Nrn Plns with 1028 mb
developing. The axis of this high will drift acrs NEB/KS tomorrow.
Rest of this afternoon: Mostly cldy. Cld bases are lifting and
will cont to do so from W-E. Patchy drzl was roughly confined to
the E 1/2 of the CWA as of 1845Z. That drzl will come to and end
as cld bases rise. Some breaks in the OVC should develop W of Hwy
Tonight: Gradual clearing and cold. This will be the coldest
night of the fall thus far. Patchy fog and possibly some patchy
frost from LXN-ODX. There could be some stratus that lingers from
GRI N and E...even past midnight.
Cold! Lows will be svrl degs below normal which we haven`t seen
much of since Sep 1.
Frost: Decided to keep the Advisory as posted from the 4 AM
shift... but am not excited about frost potential and confidence
in verifying is not high. Despite temps dropping into the 30s...
widespread stratus has lingered thru much of the day...and
probably will linger into the evening in some locations. Unless
there is decent decrease in dwpts/dry air advection...clearing in
the presence of lingering low-lvl mstr is more likely to result in
fog formation. The latent heat release would keep temps up just
enough to preclude frost.
The issue is the character of the fog. Predicting how widespread
and thick fog might be is very difficult in most situations. Given
that the fog could be patchy or confined to some areas and not
others...that might allow for a little frost to occur where fog
One other negative factor is the winds will remain 4-7 kt as
So...decided to keep the Frost Advisory but change/decrease the
fcst wording from areas to patchy. It won`t hurt to cover
sensitive vegetation W-NW of the Tri-Cities...just in case.
Thu: Any patchy fog in the AM will rapidly dissipate. Should be
sunny or mostly sunny. GFS and NAM RH cross sections suggests
there could be a some patches of altocu moving in from the SW. A
very nice day with low dwpts and light winds.
There is a quite a diff between GFS and NAM MOS for high temps.
GFS has 62F at GRI while the NAM has 53F since it hangs onto low
clds longer. Did not go as warm as the GFS but certainly favored
the warmer side of the guidance envelope.
.LONG TERM...(Thursday night through Wednesday)
Issued at 150 PM CDT Wed Oct 2 2019
Aloft: The longwave pattern that has dominated the CONUS over the
last 30 days will finally break down. The Wrn trof is fcst to
retrograde into the E Pac for a time...allowing a ridge to build
over the Wrn USA with a trof in the E. There are diff`s in the
5-10 day time frame between the EC and the GFS/CMC ensemble means.
The EC hangs onto the Wrn ridge a bit longer...whereas the
GFS/CMC means bring the trof back into Wrn Can and the NW USA.
As far as the shorter wavelengths...the shrtwv ridge will depart
NEB/KS as the deep trof moving into the W tomorrow conts E. This
trof will cross NEB/KS Sat followed by a weaker trof Sun. Once
this trof exits to the E...the flow will shift to WNW or NW Mon-
Tue as the ridge builds. Sig mdls spread dvlps over the E Pac and
Wrn USA Tue.
Surface: Fri high pres will strengthen as it heads into the
GtLks. Meanwhile...a cool front associated with the Wrn trof will
be progressing E. A low is fcst to form over WY Fri night and move
E along the SD-NEB border. This should force the cool front
(currently over KS) to lift back N as a warm front...but the cool
front moving thru the Wrn USA will quickly follow and cross the
CWA Sat AM. High pres will strengthen to about 1034 mb over the
Wrn USA and slip SE onto the Plns Mon. This high will then head
into the Ern USA Tue with modified return flow here.
Temps: remaining cooler than normal...espcly during the daytime
hrs. Some days will be much cooler than normal.
Rain: Fri into Fri night is the next chance for shwrs/tstms. A
few shwrs could linger into Sat AM. Then dry. Instability will be
minimal with the Fri system. So no strong or svr tstms are
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 725 PM CDT Wed Oct 2 2019
MVFR ceiling to prevail at least these first few hours, but rather
high confidence in VFR through the majority of the period, along
with precipitation-free conditions. There is the slightest chance
of brief MVFR visibility in light fog especially a few hours
either side of sunrise, but have only "hinted" at this with a "6SM
BR" mention. Winds will not be much of an issue, with sustained
speeds under 10KT the vast majority of the time, as direction
prevails northerly through most of the period before turning more
easterly late Thursday afternoon. Read on for more details
regarding ceiling trends...
Based on satellite trends, stubborn MVFR stratus is going to be at
least slightly slower to scatter out than previously advertised
(especially at KEAR). Am still a bit concerned that we may be too
optimistic with timing, but have aimed for a 04Z return to VFR at
both terminals (medium-confidence). Even after scattering of the
low cloud deck does occur, cannot rule out at least brief/fleeting
return of MVFR through the late-night hours. Overall though,
especially the latter half of the period for Thursday daytime
carries fairly high confidence in VFR under mostly clear skies.
NE...Frost Advisory from 3 AM to 9 AM CDT Thursday for NEZ039-040-046-
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
953 PM EDT Wed Oct 2 2019
Mainly dry weather is expected tonight as high pressure recedes
to the south, though a few showers may affect far northern
locations close to a developing cold front. There will be a
chance of showers and thunderstorms on Thursday when the cold
front is forecast to travel across the region. Much cooler
temperatures and dry weather conditions will be observed Friday
as high pressure moves back in behind the front.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Scattered showers -- generally light -- have been maintaining
their presence in the vicinity of a surface boundary this
evening. This boundary is located near the northern ILN CWA
boundary, characterized by a 10-15 degree change in temperatures
across just the latitudinal width of a few counties. Aside from
the showers, areas near and north of the boundary have also
been getting into some thicker cloud cover -- even low stratus
across parts of northern Ohio. Monitoring the trends for temps
and clouds has forced some slight adjustments to temperature and
sky grids through the overnight hours, generally in favor of
slightly cooler and cloudier conditions in the vicinity of the
boundary. PoPs were also adjusted slightly, but still with the
idea (supported by recent HRRR runs) that coverage should
diminish after the 04Z-06Z time frame. As it is, much of the ILN
forecast area should remain dry, and within an area of warm and
moist air to the south of the front.
Previous discussion >
Upper air charts show gradually decreasing geopotential heights,
though still far above normal for early October. Surface
analysis depicts high pressure moving slowly south, while a
cold front lies across Northern Ohio.
Hot temperatures persist this afternoon, with CVG DAY and CMH
having observed new record highs in the lower to mid 90s.
Models show the cold front containing ripples of short wave
energy sagging into our northern counties, necessitating a
chance of showers and a slight chance of thunderstorms tonight.
Though the models signal for precip cannot be ignored, dry air
evident on GOES water vapor channel 9 along with the rather
weak forcing south of the front suggest keeping pops lower than
model blends, with only a low chance of showers and
thunderstorms in counties north of DAY and CMH. The rest of the
area should stay free from precip through tonight, being farther
from the front and its moisture convergence and forcing.
Once breezes die down this evening, extremely hot temps will
fall off quickly, and radiational cooling and a lengthening
night should allow readings in the mid 60s by 6 am, a couple
degrees cooler than model blends.
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
While the cold front remains near our northern counties Thursday
morning, a surface low will develop and move through Northern
Ohio. Hot temperatures will persist early, especially in
southern and central locations, where readings should reach 90
again by early afternoon, with records possibly broken again at
CMH and CVG.
For Thursday afternoon, an abrupt change can be expected as the
surface low drags a cold front across the region, bringing an
end to the hot spell. Along with rapidly falling temperatures
by evening, there will also be a chance of showers and
thunderstorms, limited by rather weak forcing and instability
under a westerly flow aloft. Adjusted synoptic wind gusts up
from model blend since it appears we will see gusts close to 30
knots with frontal passage.
Any showers that develop should end Thursday night, while sky
cover lingers under an inversion around 3000 ft, especially in
northern counties. Lows in the low 50s will be over 10 degrees
cooler than in the last several nights.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
A cooler, more seasonal weather pattern will dominate the long term
period as the eastern half of the country is under the influence of
Canadian high pressure behind large scale frontal systems pushing
On Friday, northerly winds behind the departing cold front will
likely produce a period of mostly cloudy conditions north of
Interstate 70, hinted at by model 925mb and 850mb RH fields along
with very chilly 850mb temperatures pushing south over relatively
warm Lake Huron/Erie waters. Surface high pressure will build in
through the day on Friday, with decreasing winds and drying low
levels providing improving conditions into Friday evening. By
Saturday, dry conditions and additional sunshine will start a bit of
a warm up lasting into Sunday as the next frontal system approaches
from the northwest. Temperatures will a few degrees above normal on
Saturday and Sunday.
Consensus model solution has arriving shortwave energy late in the
weekend into Monday morning developing a shallow trough in the
eastern United States. This supports development of a wave along
the approaching frontal system along with likely precipitation,
especially in the southeast CWA closer to the wave. Models start to
diverge here, with the Euro and Canadian showing a slower, stronger
wave impacting our southeast counties well into Monday, while the
more progressive GFS clears the CWA by Monday morning. Took a
conservative approach, lingering showers a bit into Monday.
Cooler, drier air pushes back into the region behind the front late
Monday into Tuesday, with the center of the high centered just to
the north by Wednesday. This sends temperatures back to near or
possibly just below normal values early next week.
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Generally VFR conditions are expected through the TAF period,
though there are a few items to discuss. Showers this evening
should generally remain north of the TAF sites, with just a
slight chance that a few could affect KCMH/KLCK. While thick VFR
clouds are expected at KDAY/KCMH/KLCK tonight, some MVFR and
even IFR clouds are located not too far to the north. Though not
the most likely scenario, it is possible that some lower
ceilings could impact Columbus during the 04Z-10Z time frame.
Otherwise, some valley fog is expected at KLUK, but VFR
conditions should prevail elsewhere.
Tomorrow, winds will increase into the 10-15 knot range, with
gusts as high as 20-25 knots out of the west. Precipitation is
appearing fairly unlikely for the TAF sites, with a chance in
the afternoon at Columbus that currently appears too low to
include in the forecast. Ceilings will gradually lower through
the day, and although VFR conditions are expected through the
end of the forecast period, lower ceilings appear likely heading
into Friday morning.
OUTLOOK...MVFR ceilings are possible on Friday, mainly in the
Anomalously strong mid level ridge will persist over the area
today, leading to high temperature records at Dayton,
Cincinnati, and Columbus. Near-record highs are also possible
Thursday at Cincinnati and Columbus.
CVG 89...year 1910 & 1919
DAY 93...year 1900
CMH 89...year 1898 & 1953
ALL TIME OCT
CVG 95...year 2019 (set October 1, 2019)
DAY 94...year 2019 (set October 1 and October 2, 2019)
CMH 94...year 2019 (set October 1 and October 2, 2019)
Area Forecast Discussion
National Weather Service Northern Indiana
938 PM EDT Wed Oct 2 2019
Issued at 930 PM EDT Wed Oct 2 2019
Scattered light rain showers can be expected through the remainder
of the evening, but heavier showers along with a few isolated
thunderstorms are expected to overspread northern Indiana,
southern Lower Michigan, and far northwest Ohio overnight. Some
locally heavy rainfall is possible, especially for locations
along the Route 6 corridor extending northward across southern
Lower Michigan. Tonight`s lows are expected to stay in the mid 50s
north to mid 60s south. Dry but cooler conditions are expected
Friday into Saturday, with highs in the upper 50s and 60s.
Issued at 930 PM EDT Wed Oct 2 2019
Scattered light rain showers continue to overspread the region
this evening, but more vigorous convection has developed over past
few hours across portions of central/northern Missouri. These
storms have developed in response to amplified upper trough
progressing eastward across the Central/Northern Plains resulting
in stronger frontal response. An axis of slightly stronger
southwest flow is expected to lift northeast from Missouri across
the far southern Great Lakes. Stronger forcing with aforementioned
upper trough is expected to bypass the area to the northwest, but
a pocket of fairly deep moisture convergence/isentropic lift with
approaching low level jet and highly anomalous column moisture
(PWATs near 2 inches sampled with 00Z DVN RAOB) should allow band
of rain with perhaps few embedded thunderstorms to affect
approximately northern third of the area. Still some potential of
locally heavy rainfall given decent low/mid level moisture
convergence, excessive PWATs, and some low/mid level frontogenesis
forcing possibly coming into play. Setup appears favorable for
narrow swaths of heavier rainfall, but confidence in exactly where
these more favored areas will occur still on the low side so have
maintained area-average QPF amounts in the 0.25 to 0.5 inch
range across the northern half of the forecast area tapering to
lesser amounts south. Given recent heavy rainfall across northern
locations, some minor flooding/ponding will be possible
overnight, especially for areas receiving rainfall in excess of a
.SHORT TERM...(This Evening through Thursday)
Issued at 319 PM EDT Wed Oct 2 2019
A wind shift boundary was sinking south in IL during the afternoon
hours as northeast winds overtook west winds. At the same time,
subsidence and drying in the midlevels was observed out west in
RAP soundings. We`ll have to watch for some drizzle within this
this afternoon and evening especially as the low levels of the
atmosphere still appear very moist. Then the dryness this
afternoon is expected to be overtaken during the overnight by
moisture again as a second wave rides along the boundary north and
east towards the region. This second wave is paired with a decent
theta-e surge and available upper divergence as the low pressure
system passes overhead, however, am wondering if the
aforementioned dryness might affect how moist it can get
especially as models catch on to the aforementioned dry air so
kept QPF closer to model consensus.
Lingering rainfall especially east of IN-15 dissipates Thursday
morning as the front pushes east of the area by late afternoon.
With the tight pressure gradient across the area just behind the
front, gusty winds to 30 mph are possible. The previous warm/moist
airmass is replaced by appreciable cold/dry advection behind the
front as a deepening 1030 mb high moves into the northern Great
Lakes region. Thursday night, 850T drops down near 4 to 5C
allowing lows to drop into the 40s in many areas despite some
remnant low level moisture/cloudiness.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 319 PM EDT Wed Oct 2 2019
High pressure and upper ridging will help to allow for a sunny day
on Friday, but with 850Ts between 5 and 10C, highs will only be
able to rise toward the upper 50s to mid 60s. This is as much as
10 degrees below average for this time of year.
As the high pressure system pushes east for Saturday, another
moisture return is evident ahead of a cold front for Saturday
night. A strong low level jet over 40 kts produces some high
moisture advection, but a majority of the contribution will be
from the winds with a smaller moisture contribution this time. The
better forcing for the front translates to our north and minimal
upper level support passes overhead as the upper trough goes
negatively tilted to our northwest. This all contributes to a
lower precipitation potential for the region so will keep
consensus PoPs, but lesser QPF will be observed compared to what
we`ve seen recently.
Some upper level energy follows the frontal passage allowing for
more cloudiness and a delayed entrance of the approaching high
pressure system until the next work week. 850Ts drop towards the
low to mid single digits allowing for another fall-like cool
spell. Highs for the bulk of this long term period will struggle
to break out of the 60s for highs, which is near to slightly below
average for this time of year.
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 808 PM EDT Wed Oct 2 2019
Southward sagging frontal boundary will continue to be focal point
of some post-frontal IFR/LIFR cigs through the first half of this
forecast valid period. Wind shift to the north should occur at
KFWA over the next hour or two, along with an accompanying drop to
MVFR cigs to possibly below 2000 feet after 03Z. A pocket of some
light rain will affect KSBN in the 01Z to 04Z timeframe, but
heavier showers with perhaps isolated thunderstorms are expected
to develop later this evening across central Illinois and spread
east-northeast across northern Indiana overnight. Still some
uncertainty regarding southward extent of heavier rainfall, with
KFWA currently looking to be on southern edge of heavier rainfall.
In addition to vsby restrictions from rainfall, some fog is also
possible across the region given the slow moving frontal boundary
and abundant low level moisture. IFR/LIFR conditions will improve
late morning Thursday as primary upper trough lifts across the
Upper Midwest allowing front to more aggressively shift back
south. Windy conditions with west-northwest wind gusts of around
25 knots are expected Thursday afternoon with transition to cigs
above 2k feet and eventually VFR late.
LM...Small Craft Advisory until 11 PM EDT this evening for LMZ043-046.
Small Craft Advisory from noon Thursday to 8 AM EDT Friday for
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