Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/11/17
Area Forecast Discussion
National Weather Service Dodge City KS
604 PM CDT Tue Oct 10 2017
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Wednesday)
Issued at 207 PM CDT Tue Oct 10 2017
Early afternoon water vapor loop and RAP analysis showed center of
compact upper low over far northeastern KS, which continued to pull
away from the Central Plains. Weak shortwave ridging was moving
across Colorado in its wake. The surface high behind the departing
system was quite weak, with only a 1026mb ridge, more or less,
extending from southeastern SD into southwestern KS. Winds will drop
off quite a bit at sundown, and we expect a prolonged period of wind
speeds of 6 knots or less. Clear sky, light winds, and dewpoints
around 30F will allow temperatures to fall through the 30s after
midnight. There is still a little bit of uncertainty regarding how
large of an area will see 32 degrees or colder temperature for a
low, but there is a typical diurnal fall of 25 degrees from today`s
highs in this good radiational cooling environment would certainly
support a number of counties in west central Kansas reaching 32F for
a low. As a result of this thinking, will be hoisting a Freeze
Warning for areas generally north of the Arkansas River, and a Frost
Advisory south of this (excluding far south central KS). Thanks to
WFO GLD, GID, AMA, PUB, ICT for coordinating the frost/freeze
hazard.
This will be the last cold morning for awhile, as we will be
entering a warmer pattern with the upper level flow pattern becoming
southwesterly Wednesday. This will foster development of the leeside
trough and south-southwest winds will be on the increase as a
result, particularly far southwest and west central KS in the
afternoon where MSLP gradient will be stronger. This area will also
be the first to see downslope momentum, leading to afternoon
temperatures topping out in the lower 70s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 207 PM CDT Tue Oct 10 2017
Not much change in the overall thinking from previous forecast, as
we continue to anticipate a nice warming trend back into the 80s
Thursday and Friday. The next front Friday, though, looks a touch
faster than what it looked like yesterday, so the 80s will likely
only be realized closer to the Oklahoma border. Areas of far west
central KS may struggle to escape the 60s. This will likely be a dry
front Friday/Friday Night, with much of the initial thunderstorm
activity found farther northeast across far northeast KS/northwest
MO. That said, the GFS is definitely a more vigorous solution with
the QPF field, and as a result, SuperBlend POPs are higher (30-40
percent 06-12z Saturday). The front will likely stall out across
southern/central KS with increasing low level moisture pulling
northward toward it. The ECMWF, GFS, Canadian models all show a
similar signal of slightly positively tilted upper trough from the
western Dakotas into Colorado, which is generally not very favorable
for precipitation in western Kansas in mid-Fall.
Very strong cold frontogenesis usually results, and all three models
show this happening late in the day Saturday. Saturday looks like a
much better chance for more organized strong/severe thunderstorms,
potentially affecting our southeastern counties (south central
Kansas). SuperBlend POPs of 40-50 percent are in the grids for areas
east of Larned to Greensburg to Coldwater, although my gut tells me
the best activity will probably be east into WFO ICT forecast area
deeper into south central and eastern KS. Temperatures Sunday look
quite cool as intense low level cold advection will drive south
lower single digit Celsius temperatures at 850mb, supporting Sunday
highs in the upper 50s to lower 60s most locations. Look for the
Sunday highs to be a bit lower in future updates if these latest
global model trends continue regarding magnitude of cold air behind
this trough.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 603 PM CDT Tue Oct 10 2017
A trough of low pressure at the surface will begin to develop
across eastern Colorado overnight as a surface high moves across
eastern Kansas. The light north/northeasterly winds will shift to
the south by early Wednesday morning. These southerly winds will
increase through the day and are expected to be in the 15 to 20
knot range by 18z Wednesday. Model soundings indicating VFR
conditions over the next 24 hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 33 70 49 83 / 0 0 0 0
GCK 32 71 47 84 / 0 0 0 0
EHA 35 74 51 85 / 0 0 0 0
LBL 35 73 50 86 / 0 0 0 0
HYS 33 67 46 80 / 0 0 0 0
P28 36 69 49 81 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 1 AM CDT /midnight MDT/ to 9 AM CDT /8 AM
MDT/ Wednesday for KSZ030-031-043>046-061>064.
Frost Advisory from 1 AM to 9 AM CDT Wednesday for KSZ065-066-
074>080-084>088.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Green Bay WI
1023 PM CDT Tue Oct 10 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 233 PM CDT Tue Oct 10 2017
The latest RAP analysis and satellite/radar imagery show low
pressure spinning over the central Mississippi Valley, and a
Canadian high pressure from the northern Great Lakes to the west-
central Great Plains. Rain showers from the surface low are
lifting northward over eastern Iowa and western Illinois, but are
running into dry air emanating out of the high to the north. Mid-
level clouds are beginning to move into central WI early this
afternoon, and this increasing cloud trend will continue for the
rest of the day. As the low pressure moves northeast, precip
chances and trends are the main forecast concerns.
Tonight...The low pressure system will track across central
Illinois and Indiana. Central and northeast Wisconsin will be on
the northern periphery of the system, with a continued feed of low
level dry airmass from the northeast. This may hold off precip for
a while, but should see enough push of moisture for precip chances
to ramp up over central to east-central WI early to mid-evening.
Have increased pops based on more bullish model solutions. Areas
south of Wisconsin Rapids to Kewaunee will stand the highest
chance of rainfall. The precip will likely pull out of central WI
late tonight. Farther north, will see an increase of mid-level
clouds during the evening, but dry air is too entrenched for
precip. Low temps will range from the low 30s north to near 50
south.
Wednesday...Any lingering shower activity is expected to exit
east-central WI early in the morning. Then high pressure will
reassert itself for the rest of the day. Will likely see more
clouds linger over central than northern parts of the state. Highs
ranging from near 60 in the north to mid 60s south.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 233 PM CDT Tue Oct 10 2017
The main forecast concern will be precipitation trends, and
the potential for heavy rain and thunderstorms, over the weekend.
Expect a period of quiet weather from Wednesday night through
Thursday night. Precipitation will return Friday into Friday
night, as light to moderate post-frontal rain develops in the
wake of a cold frontal passage.
Models are coming into better agreement with the timing and track
of a surface low that lifts northeast along the lingering frontal
boundary over the weekend. Both the GFS and ECMWF track the low
through southeast WI Saturday night, before taking it into the
eastern Great Lakes Sunday evening. This system will have fairly
potent dynamics, plus PWATs around 1.5 inches and some elevated
instability over our southeast counties. Current indications are
that rain will overspread the area during the late afternoon and
evening on Saturday, becoming heavy at times over parts of central
and east central WI Saturday night before gradually tapering off
Sunday afternoon or evening. Have added a slight chance of
thunderstorms to the southeast portion of the CWA Saturday night.
Quiet weather returns for the early part of the work week.
Temperatures will warm to above normal late in the work week,
return to near normal over the weekend, then moderate a bit
again toward the end of the forecast period.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1021 PM CDT Tue Oct 10 2017
VFR conditions should prevail through Wednesday afternoon despite
rain across portions of central and east-central Wisconsin into
Wednesday morning. The rain is still expected to stay south of a
KAUW to KSUE line. The rain will gradually shift to the southeast
and end overnight or early Wednesday morning as low pressure
moves away from the area. Gusty east/northeast winds can be
expected across east-central Wisconsin for the overnight hours,
and across the entire area on Wednesday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......Eckberg
Area Forecast Discussion
National Weather Service Jacksonville FL
920 PM EDT Tue Oct 10 2017
.UPDATE...
Isolated to scattered showers and a thunderstorm or two continue
this evening over the western zones moving very slowly east over GA
and moving west over inland northeast FL. The convection is forecast
to dissipate later tonight with loss of heating and weakening low
level convergence. The HRRR suggests some overnight activity still
over inland SE GA but think coverage would be less than 15%. There
is some model agreement that a few showers will be possible near the
southeast GA coast by sunrise so will continue with a mention of an
isolated shower there. Otherwise...light winds and mostly clear
conditions should be supportive of patchy fog toward the early
morning hours. Lows will again be above normal in the lower 70s.
&&
.AVIATION...VFR through late tonight. A good chance of stratus and
some light fog potential overnight...mainly JAX, GNV, and VQQ.
Mainly dry conditions will exist for terminals on Wednesday...
with sct to numerous showers and storms northwest of aerodromes
over southeast GA.
&&
.MARINE...Current forecast looks on track with southeast winds
near 10-15 kt and seas of about 2-4 ft nearshore and 3-5 ft
offshore. Winds may drop off a few knots by early morning. No
major changes expected.
Rip Currents: Moderate risk of rip currents continues due to east
to southeast swells near 2-3 ft and southeast winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 73 88 72 88 / 30 60 10 20
SSI 75 86 75 85 / 20 20 0 0
JAX 73 88 71 86 / 10 10 0 0
SGJ 73 85 72 85 / 0 0 0 0
GNV 71 89 68 89 / 0 10 0 0
OCF 70 90 68 89 / 10 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 8 AM EDT Wednesday for Clay-Coastal
Duval-Flagler-Inland Duval-Putnam-St. Johns.
GA...None.
AM...None.
&&
$$
Shashy/Nelson/Corless
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1055 PM EDT Tue Oct 10 2017
.UPDATE...
Issued at 1050 PM EDT TUE OCT 10 2017
Hourly grids have been freshened up based on recent observations
and trends. This was to account for shower activity in the
vicinityof I-75 and to time in precipitation chances later
tonight as the cold front moves into and across the area. Fog has
developed in a few locations, but the approaching cold front and
anticipated cloud cover should limit the coverage.
UPDATE Issued at 755 PM EDT TUE OCT 10 2017
A band of showers with some embedded thunderstorms continues to
push north and northeast across the area as a warm front lifts
north across the region. Meanwhile, a surface low pressure system
and associated mid level wave is passing by to the northwest of
the area. Additional convection was moving across western KY in
the vicinity of the trailing cold front. This convection should
weaken with the loss of daytime heating, but with the cold front
and shortwave trough axis yet to cross the area, additional
showers and perhaps a thunderstorm cannot be ruled out overnight
after the initial band of showers lifts north and east of the
area. The most recent HRRR has some additional development over
parts of Central and Eastern KY later this evening. Outside of
any convection, the airmass remains moist and fog and low stratus
or stratocu will be possible, especially as the front nears late
tonight.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 411 PM EDT TUE OCT 10 2017
A center of surface low pressure is currently making its way
across eastern Missouri, and will continue to lift northeastward
into Illinois this evening and overnight as the associated surface
fronts begin to occlude. Eastern Kentucky will find itself in the
warm sector, ahead of the cold front this evening and overnight,
with rain overspreading the region. Chances of thunderstorms are
expected through at least the evening. Best instability will be
lost during the overnight as surface temperatures cool, and allow
for a near surface inversion, preventing lift. The front itself
will also be weakening, also reducing the amount of instability to
play with. That being said, can`t rule out a rogue storm or two,
but confidence not high enough to include thunder in forecast for
the overnight at this time.
The cold front is expected to push through eastern Kentucky during
the first half of the day tomorrow. There is some question as to
whether or not thunder will occur during the day as temperatures
warm, however based on latest NAM12 soundings it looks like
instability will be shallow and limited to about a 3 to 5 hour
window in the afternoon just before the front passes through and
cooler/drier flow cuts off best lift potential. Given the
uncertainty and short window, chose to leave out of forecast at
this time. Rain will quickly taper off throughout the afternoon
behind the front as drier air filters into the region.
Temperatures will still make it into the mid to upper 70s, topping
around 80 in the east which will experience the most prefrontal
warming.
.LONG TERM...(Thursday through Tuesday)
Issued at 325 PM EDT TUE OCT 10 2017
The models are in fairly good agreement aloft through at least the
first part of the weekend before differences build between the GFS
and ECMWF. They all depict a resurgence to the southeast ridging
from Thursday through Saturday before a well defined trough coming
out of the Rockies starts to shave the northern extent of the higher
heights. This trough, stronger and a tad slower in the ECMWF than
the GFS, lifts into the Central Plains and Upper Midwest this
weekend. The passage of this feature will help to drive lower
heights into the Ohio Valley to start the next work week. Locally,
it looks like the mid level trough axis will pass through Kentucky
on Monday with the ECMWF sweeping its core energy by to the north
later that night. Moderating heights will follow as the pattern
settles for a bit. Given the decent agreement with the models, even
the differences late in the period are not too concerning, will look
to make only minor timing adjustments to the starting blend.
Sensible weather will feature dry and seasonably warm weather
through the weekend as high pressure holds over the area. However,
flow coming around its backside will serve to support higher
dewpoints and a buildup in moisture as we head toward the start of
next week. A cold front will ease into the state late Sunday with
showers and a few thunderstorms possible. This boundary will then
slowly press southeast during the night and into Monday morning with
a change in air mass to follow. High pressure then builds into the
state with cooler, but still seasonable, conditions through at least
Tuesday.
Made some typical terrain based adjustments to the grids most nights
during the extended, aside from Sunday, with the front. As for PoPs,
lowered some of the small chances well ahead of the front and
lingering in its wake.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 828 PM EDT TUE OCT 10 2017
In the vicinity of a warm front, a band of showers with a stray
thunderstorm continues to lift north and east across the area.
These have been reducing visibilities into the MVFR range at times
as they pass with CIGS generally MVFR or higher. The chances for
showers will linger overnight in advance of the front with some
MVFR fog possible in spots. Low level moisture should increase
overnight and linger into Wednesday as the front nears and moves
across the region. CIGS should lower into the MVFR if not the IFR
range for western locations between 6Z and 12Z as the cold front
nears with some MVFR eventually possible further east at SJS for
a few hours as the front passes. Gradual improvement back toward
VFR will occur from then until end of the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JP
Area Forecast Discussion
National Weather Service Midland/Odessa TX
633 PM CDT Tue Oct 10 2017
.DISCUSSION...
See 00Z aviation discussion below.
&&
.AVIATION...
VFR conditions and light north to northeast winds becoming
southeasterly overnight into early Wednesday.
&&
.PREV DISCUSSION... /issued 245 PM CDT Tue Oct 10 2017/
DISCUSSION...
WV imagery shows the upper trough over ern KS, and its associated
cold front has reached the Gulf Coast, leaving West Texas and
Southeast New Mexico in a dry slot as post-frontal northerly sfc
flow continues. As sfc high pressure moves east overnight, sfc flow
will veer around to SE, and begin returning Gulf moisture back into
the area.
West Texas and Southeast New Mexico will remain under SW flow aloft
thru the weekend as the upper ridge centered over the lwr east coast
develops westward. As it does, increasing thicknesses are still on
tap for a nice warmup to abv-normal temperatures by Thursday
afternoon.
Next big chance of rain looks to be as soon as Friday night, when
60F sfc dewpoints will be backed up as far west as KCNM. The GFS is
persistent in bringing a shortwave up out of Mexico and into SE NM,
w/the RR quadrant of the 250mb jet over nrn NM to assist. Other
long-range models are not so enthusiastic, so POPs remain on the low
side. This activity is forecast to carry over into Saturday, w/the
vort axis shifting into West Texas. Finally, long-range models bring
a cold front into the CWA beginning 12Z Sunday, which will bring
another round of convection, and knock temps back down to- or below-
normal into the rest of the extended.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 45 75 58 84 / 0 0 0 0
Carlsbad 45 76 54 85 / 0 0 0 0
Dryden 55 75 61 82 / 0 0 0 0
Fort Stockton 51 79 59 86 / 0 0 0 0
Guadalupe Pass 46 73 57 80 / 0 0 0 0
Hobbs 41 73 52 82 / 0 0 0 0
Marfa 44 78 53 81 / 0 0 0 0
Midland Intl Airport 47 75 59 84 / 0 0 0 0
Odessa 47 75 58 83 / 0 0 0 0
Wink 47 76 57 85 / 0 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
99/99/10
Area Forecast Discussion
National Weather Service Medford OR
836 PM PDT Tue Oct 10 2017
.SHORT TERM...A period of cool and shower weather is expected
across the area through Friday. A cold front is moving inland
this evening and has brought showers to the coast and Umpqua
Valley. Showers are expected to spread inland tonight with a
chance for showers across many areas from the Southern Oregon
Cascades west. Some light showers are also expected to spread into
areas east of the Cascades. For northern California, expect
little if any showers.
An upper trough moves inland on Wednesday and will bring a cool,
moist airmass to the area with additional showers over southern
Oregon. Another front is expected to move into the area on
Thursday followed by an upper level shortwave that moves around
the upper trough and into the area Friday. This will bring a
continued cool and showery pattern to the region. Daytime high
temperatures are expected to be around 8 to 15 degrees lower than
normal through Friday. Snow levels are expected to be around 4000
to 5000 feet in the Southern Oregon Cascades Wednesday through
Thursday and may be locally lower at times. The lower snow levels
combined with showers will result in some light snow accumulations
at the higher passes in the Cascades. Gusty west winds are
expected in the afternoons and evenings through Friday, especially
for areas from the Cascades east.
A drier and warmer pattern sets up Saturday and Sunday as an upper
ridge moves into the region from the west. A thermal trough will
develop along the coast and is expected to bring periods of gusty
northeast winds to the ridges, especially from the Cascades west,
on the weekend.
&&
.AVIATION...A cold front is moving inland,
bringing northwest winds, cloud cover, and scattered precipitation.
MVFR to VFR cigs will continue throughout the TAF period. Expect
terrain obscuration of the Coastal Range and Cascades. Inland areas
are seeing lowered vis due to smoke, mainly from the Abney fire near
the Applegate Valley. Smoke impacts should diminish this evening as
northwest flow dominates. Can`t completely rule out a shower or two
at any of the TAF terminals... though this front will be relatively
dry. Also of note, freezing levels will drop significantly
tonight...to 4500-5500 feet MSL over most of the area by tomorrow
morning. So, higher elevations could see snow... and any precip that
reaches the East Side could fall as snow. -MSC
&&
.MARINE...A cold front is moving onshore this evening. A cold and
showery air mass moves into place tonight and Wednesday with
periods of gusty north winds. Steep northwest swell over the
waters will build tonight through Wednesday, peaking Wednesday
evening. Winds and seas will diminish slightly Thursday into
Friday. Another weak front will move across the waters on
Thursday then inland Friday. A thermal trough will develop Friday
night along the coast and deepen over the weekend. This will
result in strong north winds and choppy steep to very steep, wind
driven seas developing over the waters, especially for areas from
Cape Blanco southward.
&&
.PREV DISCUSSION... /Issued 257 PM PDT Tue Oct 10 2017/
DISCUSSION...The cold front is moving into Coos County this
afternoon. Southwest winds ahead of this front are gusting up to
25 mph in Lakeview and Alturas. The short term models raises the
winds in the Klamath Basin and the Shasta Valley around 5 PM to
around 15 mph. So far not much precipitation is falling with the
front and we do not expect much until after the front has moved
through. Onshore flow behind the front and upslope flow into the
Cascades and Siskiyous will lead to a better chance of showers
tonight, mainly from the Cascades west and Siskiyous north. Only
isolated showers are expected in the Happy Camp area, northern
Klamath County and the Warner Valley in eastern Lake County. The
HRRR short term model suggests moderate showers into the
Kalmiopsis Wilderness and the Illinois Valley around daybreak.
With cold air aloft at 500hPa, we could also see isolated
lightning strikes in the coastal waters north of Cape Blanco and
inland into western Douglas County during the day but at this
point we do not expect more lightning strikes elsewhere in our
forecast area. Snow levels on Wednesday will be around 4500 ft in
the Cascades and closer to 5000 feet in the Siskiyous and 5500
feet in the Warners. Around an inch of snow is possible at Crater
Lake on Wednesday with precipitation tapering off Wednesday night.
On Thursday, a broad trough remains over the forecast area with a
sharp short wave trough bringing another round of showers Thursday
afternoon and Thursday night. While the snow level on Thursday
night will be higher, at 5300-5700 feet, there will also be more
precipitation with this trough and Crater Lake could receive 6 to
8 inches of more snow and 2 to 3 inches of snow over Highway 140
pass over the Cascades. Little to no impact is expected at the
Sexton Pass and Siskiyou Pass on I-5 at this time as the snow
level will be above those pass elevations. The higher elevation of
Highway 97 in northern Klamath County around Chemult could see
around an inch of snow Wednesday night with Quartz Mountain Pass
on Highway 140 in eastern Klamath and western Lake County seeing
around half an inch.
The trough lifts east of the area on Friday with a drying trend
into the weekend, albeit under a cool NW flow aloft. There could
be a fire weather Friday through the weekend from offshore flow
and thermal trough along the coast with low humidity.
The next chance of significant rain will be Tuesday or Tuesday
night. Confidence is moderate and approaches high that we could
see wetting rain across SW Oregon with showers east of the
Cascades/ /FB
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...Small Craft Advisory for hazardous seas until 5 AM PDT Thursday
for PZZ350-356-370-376.
$$
CC
Area Forecast Discussion
National Weather Service Marquette MI
623 PM EDT Tue Oct 10 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 401 PM EDT TUE OCT 10 2017
WV imagery and RAP analysis indicated mainly zonal nrn stream
mid/upper level flow through srn Canada and a vigorous shortwave
trough over ne KS in the srn stream. At the surface, a ridge
extended from MN through Lake Superior and portions of nrn
Ontario atop a low from se MO into srn IL. Considerable mid/high
clouds were spreading through rn WI and Upper Michigan while the
pcpn remained well to the south the with nrn edge into far se MN
and sw WI.
Tonight, Confluent mid/upper level flow and the strong sfc high, dry
nrly flow and associated subsidence over the area will keep pcpn
from the MO shrtwv to the south of the cwa, per short range models
and radar trends. Otherwise, favorable radiational cooling
conditions under high pressure with light winds across may be
limited by some lingering high clouds, especially over the south.
Nevertheless, expect temps near the lower end of model guidance with
min temps ranging from the upper 20s western interior to upper 30s
and lower 40s at many Great Lakes shoreline locations.
Wednesday, another day with the sfc ridge dominating and mostly
sunny skies will bring moderating temps with max readings slightly
above normal. Mixing to only around 900 mb (6C) with the strong
prevailing subsidence will still push temps to around 60.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 408 PM EDT TUE OCT 10 2017
The main weather impacts in the extended will be rain potential
Friday into Friday night and again Saturday night into Sunday. The
weekend system may also produce some gusty winds, depending on the
exact strength of the system.
Wednesday night through Thursday night: High pressure will remain in
control of the weather through this time period as it shifts slowly
to the east. At the same time, a vertically stacked low pressure
system over Manitoba is expected to shift very slowly into northern
Ontario. The low pressure system will have very little impact on the
U.P. weather through this time period, with skies remaining partly
cloudy and mainly dry conditions expected. Highs and lows will run
above normal for this time period.
Friday into Friday night: The aforementioned low pressure system
will trek across Northern Ontario into Hudson Bay during this time
period. As this happens, an associated cold front will slide across
the U.P. Friday afternoon into Friday night. Along and ahead of the
cold front, moisture and forcing will increase across the area. This
will allow widespread rain showers to develop across much of the
U.P., again, the best time frame for this will be during the
afternoon into the evening hours. At this point, it looks like
instability will be minimized, so thunder potential will not be
mentioned in the forecast. Otherwise, due to the faster movement of
the front, not really expecting too much more than a quarter inch or
so of rainfall through Friday night. Temperatures are expected to be
above normal Friday before slowly dropping below normal Friday night.
Saturday and Sunday: Models are in closer agreement with the weekend
low pressure system expected to move through the area; however,
there are still some minor differences in intensity. Both models
still have the low moving just southeast of the U.P. Saturday night
into Sunday, bringing widespread rainfall to much of the U.P. The
more concentrated area of rain looks to be over the southeast half
at this point. The upper level low is shown to be more open by both
the GFS and EC, keeping the surface low much weaker than the
previous EC model run had been showing. This would lend support for
less gusty winds that may have been expected otherwise. The system
will need to be watched; however, as the models have be flip-
flopping on the solutions over the last few days.
Rest of the extended: Another trough may pass through the area
Monday, bringing yet another potential for rains showers; however,
due to poor model timing, will stick with a consensus of the models
for this time period. This would provide near normal temperatures
along with mainly dry conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 623 PM EDT TUE OCT 10 2017
VFR conditions will continue through the forecast period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 401 PM EDT TUE OCT 10 2017
With high pressure over the area winds will remain below 20 knots
through Wednesday. Southerly winds will increase to 25 knots ahead
of a trough moving into the region on Thursday but will drop off to
20 knots or less by Friday. There is lingering uncertainty with the
timing/location and strength of a low pressure system moving
northeast into the Western Great Lakes by Sunday. Nrly winds to 30
knots will be possible but could increase to gales if a stronger
system develops as some recent model runs have shown.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...07
MARINE...JLB
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
937 PM EDT Tue Oct 10 2017
.DISCUSSION...
Most shower activity has ended across the area, and the 00Z OHX
sounding shows some midlevel dry air that will be coming our way.
The update will adjust PoPs downward overnight. However, there is
a line of convection in West TN ahead of the cold front that is
projected to reach our area around 10-12Z. Latest HRRR runs also
show some redevelopement of showers in the Valley, so low to
slight chances will be maintained overnight. Adjustments to temps
and dewpoints will also be made to better match obs.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
DGS
Area Forecast Discussion
National Weather Service Nashville TN
939 PM CDT Tue Oct 10 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Narrow band of showers and tstms is pushing toward our western
areas with the man frontal boundary providing the forcing. Hrrr
indicating the activity will weaken but latest trends showing
that the convection is maintaining its current coverage and
intensity. Will opt to increase pops some across our southwest.
Models still lean toward a decrease in forcing over the next few
hours. Otw, temps still look to be on track as values drop off in
the upper 50s behind the front. Update out shortly.
&&
.AVIATION...
00Z TAF DISCUSSION.
Sfc low over central IL will lift northward overnight. As this
happens, the rainfall across the area will diminish prior to 06z.
The cloudiness, however, will hang on through the night and into
the 12z-18z timeframe as well. Some late night light fog will
occur along with mvfr cigs. Partial clearing will commence,
generally after 18z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......21
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Wednesday)
Issued at 245 PM CDT Tue Oct 10 2017
19Z water vapor imagery shows an upper low over northeast KS
lifting to the northeast. Another upper low was moving onshore
over the Pacific Northwest. At the surface, high pressure
stretched from the southern high plains to the upper Midwest.
Cloud cover and low level cold air advection continued into the
afternoon and temps have remains in the lower and middle 40s.
For tonight and Wednesday, the weather should remain dry. As the
upper low continues to lift northeast, subsidence should increase.
Combined with dry air advecting in with the surface ridge, there
is little chance of precip tonight or Wednesday. So focus shifts
to temps. Conditions for radiational cooling look favorable across
north central KS where the ridge axis is forecast to move into,
with skies clearing out. However the RAP and NAM hang onto the low
clouds over eastern KS through much of he night. So where skies
are forecast to clear out, lows should drop into the lower 30s
while cloud cover over eastern KS keeps temps in the mid 30s to
near 40. Based on this forecast, have issued frost advisories and
freeze warnings for north central KS and parts of northeast KS.
This forecast is heavily dependent on the cloud cover forecast, so
the evening shift will need to watch how the clouds clear out and
make any adjustments to the headlines as needed. Surface ridging
is expected to remain over the area through the day Wednesday. So
there is not expected to be a great deal of mixing and surface
winds maintain a light easterly component. So highs Wednesday are
expected to remain on the cool side. Mostly sunny skies by the
afternoon should help temps warm into the lower and middle 60s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 245 PM CDT Tue Oct 10 2017
A gradual warming trend will set in for the latter part of the week
with the next major chance of showers and storms arriving on
Saturday.
Broad cyclonic flow will be in place over the western and central
CONUS at the start of the period, facilitating the return of warm
southerly winds. A northern stream wave will drag a cold front
southeastward across the Dakotas and Nebraska on Thursday. Lee
cyclogenesis will take place along the Front Range on Thursday
night and into early Friday with the cyclone gradually drifting
northeastward and reinforcing the decaying cold front. Highs on
Thursday will reach into the 70s across NE Kansas, but surge into
the low to mid 80s (upper 80s are possible) in areas ahead of the
boundary as ample WAA takes place. The upper level blocking
pattern breaks down late in the week with a sharp shortwave trough
ejecting ENE across the central plains.
The increase in kinematic support coupled with the strengthening Fg
forcing will fuel shower and thunderstorm development both late
Friday and again Saturday afternoon. The GFS/EC/GEM are in general
agreement with the position of the boundary and upper level
features, but there remain enough mesoscale differences to warrant
some degree of uncertainty. The CAPE-shear profiles ahead of this
boundary would be supportive of strong convective storms, but with
the mid to upper level steering flow parallel to the surface
boundary, it is likely that any storms will quickly grow upscale
into a linear line. GFS bufr soundings depict 0-1 km helicity values
of 200-300 m2/s2 with 0-3 km shear values of 30-40 kts. Thus, there
would exist a non-zero tornado threat should this scenario come to
fruition in addition to wind and hail. Heavy rainfall would be a
threat given PWATS of 1.5 to 2 inches and the possibility of
training cells, but the fast storm motions of 40 to 50 kts would
work somewhat against a flooding scenario.
This complex will quickly exit early Sunday with Canadian high
pressure and seasonal temperatures sliding southward to start next
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 615 PM CDT Tue Oct 10 2017
MVFR ceilings are expected to shift east of the area at MHK within
the hour, and at TOP/FOE near 05Z. There are some model solutions
which hold on to the clouds a bit longer so this possibility will
continue to be monitored. Once the low clouds clear, VFR is
expected to prevail with light winds throughout the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from midnight tonight to 10 AM CDT Wednesday for
KSZ010-022-035>037.
Freeze Warning from midnight tonight to 10 AM CDT Wednesday for
KSZ008-009-020-021-034.
&&
$$
SHORT TERM...Wolters
LONG TERM...Skow
AVIATION...Heller